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Srivastava S, Koh HY, Smith L, Poduri A. Cerebral Palsy Phenotypes in Genetic Epilepsies. Pediatr Neurol 2024; 157:79-86. [PMID: 38901369 DOI: 10.1016/j.pediatrneurol.2024.05.016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/02/2023] [Revised: 03/03/2024] [Accepted: 05/26/2024] [Indexed: 06/22/2024]
Abstract
BACKGROUND Although there are established connections between genetic epilepsies and neurodevelopmental disorders like intellectual disability, the presence of cerebral palsy (CP) in genetic epilepsies is undercharacterized. We performed a retrospective chart review evaluating the motor phenotype of patients with genetic epilepsies. METHODS Patients were ascertained through a research exome sequencing study to identify genetic causes of epilepsy. We analyzed data from the first 100 individuals with molecular diagnoses. We determined motor phenotype by reviewing medical records for muscle tone and motor function data. We characterized patients according to CP subtypes: spastic diplegic, spastic quadriplegic, spastic hemiplegic, dyskinetic, hypotonic-ataxic. RESULTS Of 100 individuals with genetic epilepsies, 14% had evidence of possible CP, including 5% characterized as hypotonic-ataxic CP, 5% spastic quadriplegic CP, 3% spastic diplegic CP, and 1% hemiplegic CP. Presence of CP did not correlate with seizure onset age (P = 0.63) or seizure control (P = 0.07). CP occurred in 11% (n = 3 of 27) with focal epilepsy, 9% (n = 5 of 54) with generalized epilepsy, and 32% (n = 6 of 19) with combined focal/generalized epilepsy (P = 0.06). CONCLUSIONS In this retrospective analysis of patients with genetic epilepsies, we identified a substantial portion with CP phenotypes, representing an under-recognized comorbidity. These findings underscore the many neurodevelopmental features associated with neurogenetic conditions, regardless of the feature for which they were ascertained for sequencing. Detailed motor phenotyping is needed to determine the prevalence of CP and its subtypes among genetic epilepsies. These motor phenotypes require clinical management and represent important targeted outcomes in trials for patients with genetic epilepsies.
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Affiliation(s)
- Siddharth Srivastava
- Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts; Department of Neurology, Rosamund Stone Zander Translational Neuroscience Center, Boston Children's Hospital, Boston, Massachusetts; Harvard Medical School, Boston Children's Hospital, Boston, Massachusetts; Cerebral Palsy and Spasticity Center, Boston Children's Hospital, Boston, Massachusetts
| | - Hyun Yong Koh
- Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts; Neurogenetics Program and Epilepsy Genetics Program, Boston Children's Hospital, Boston, Massachusetts
| | - Lacey Smith
- Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts; Neurogenetics Program and Epilepsy Genetics Program, Boston Children's Hospital, Boston, Massachusetts
| | - Annapurna Poduri
- Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts; Department of Neurology, Rosamund Stone Zander Translational Neuroscience Center, Boston Children's Hospital, Boston, Massachusetts; Harvard Medical School, Boston Children's Hospital, Boston, Massachusetts; Neurogenetics Program and Epilepsy Genetics Program, Boston Children's Hospital, Boston, Massachusetts.
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Mayer A, Derua R, Spahn E, Verbinnen I, Zhang Y, Wadzinski B, Swingle MR, Honkanen R, Janssens V, Xia H. The role of liprin-α1 phosphorylation in its liquid-liquid phase separation: regulation by PPP2R5D/PP2A holoenzyme. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.06.18.599485. [PMID: 38948786 PMCID: PMC11213027 DOI: 10.1101/2024.06.18.599485] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/02/2024]
Abstract
Liprin-α1 is a widely expressed scaffolding protein responsible for regulating cellular processes such as focal adhesion, cell motility, and synaptic transmission. Liprin-α1 interacts with many proteins including ELKS, GIT1, liprin-β, and LAR-family receptor tyrosine protein phosphatase. Through these protein-protein interactions, liprin-α1 assembles large higher-order molecular complexes; however, the regulation of this complex assembly/disassembly is unknown. Liquid-liquid phase separation (LLPS) is a process that concentrates proteins within cellular nano-domains to facilitate efficient spatiotemporal signaling in response to signaling cascades. While there is no report that liprin-α1 spontaneously undergoes LLPS, we found that GFP-liprin-α1 expressed in HEK293 cells occasionally forms droplet-like condensates. MS-based interactomics identified Protein Phosphatase 2A (PP2A)/B56δ (PPP2R5D) trimers as specific interaction partners of liprin-α1 through a canonical Short Linear Interaction Motif (SLiM) in its N-terminal dimerization domain. Mutation of this SLiM nearly abolished PP2A interaction, and resulted in significantly increased LLPS. GFP-liprin-α1 showed significantly increased droplet formation in HEK293 cells devoid of B56δ (PPP2R5D knockout), suggesting that PPP2R5D/PP2A holoenzyme inhibits liprin-α1 LLPS. Guided by reported liprin-α1 Ser/Thr phosphorylation sites, we found liprin-α1 phospho-mimetic mutant at serine 763 (S763E) is sufficient to drive its LLPS. Domain mapping studies of liprin-α1 indicated that the intrinsically disordered region, the N-terminal dimerization domain, and the SAM domains are all necessary for liprin-α1 LLPS. Finally, expression of p.E420K, a human PPP2R5D variant causing Houge-Janssens Syndrome type 1 (also known as Jordan's Syndrome), significantly compromised suppression of liprin-α1 LLPS. Our work identified B56δ-PP2A holoenzyme as an inhibitor of liprin-α1 LLPS via regulation at multiple phosphorylation sites.
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Mahale R, Arunachal G, Chadha D, Padmanabha H, M P, Pavagada M. Early-onset levodopa responsive parkinsonism in PPP2R5D mutation. Parkinsonism Relat Disord 2024; 123:106952. [PMID: 38582018 DOI: 10.1016/j.parkreldis.2024.106952] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/19/2024] [Revised: 03/28/2024] [Accepted: 03/29/2024] [Indexed: 04/08/2024]
Affiliation(s)
- Rohan Mahale
- Department of Neurology, National Institute of Mental Health and Neurosciences (NIMHANS), Bangalore, 560029, India.
| | - Gautham Arunachal
- Department of Human Genetics, National Institute of Mental Health and Neurosciences (NIMHANS), Bangalore, 560029, India
| | - Deepak Chadha
- Department of Neurology, National Institute of Mental Health and Neurosciences (NIMHANS), Bangalore, 560029, India
| | - Hansashree Padmanabha
- Department of Neurology, National Institute of Mental Health and Neurosciences (NIMHANS), Bangalore, 560029, India
| | - Pooja M
- Department of Neurology, National Institute of Mental Health and Neurosciences (NIMHANS), Bangalore, 560029, India
| | - Mathuranath Pavagada
- Department of Neurology, National Institute of Mental Health and Neurosciences (NIMHANS), Bangalore, 560029, India
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Zreibe K, Kanner CH, Uher D, Beard G, Patterson M, Harris M, Doerger J, Calamia S, Chung WK, Montes J. Characterizing ambulatory function in children with PPP2R5D-related neurodevelopmental disorder. Gait Posture 2024; 110:77-83. [PMID: 38547676 PMCID: PMC11056288 DOI: 10.1016/j.gaitpost.2024.03.012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/22/2023] [Revised: 01/29/2024] [Accepted: 03/22/2024] [Indexed: 04/14/2024]
Abstract
BACKGROUND Individuals with PPP2R5D-related neurodevelopmental disorder have an atypical gait pattern characterized by ataxia and incoordination. Structured, quantitative assessments are needed to further understand the impact of these impairments on function. RESEARCH QUESTION How do gait parameters and ambulatory function of individuals with PPP2R5D-related neurodevelopmental disorder compare to age and sex matched healthy norms? METHODS Twenty-six individuals with PPP2R5D pathogenic genetic variants participated in this observational, single visit study. Participants completed at least one of the following gait assessments: quantitative gait analysis at three different speeds (preferred pace walking (PPW), fast paced walking (FPW) and running, six-minute walk test (6MWT), 10-meter walk run (10MWR), and timed up and go (TUG). Descriptive statistics were used to summarize gait variables. Percent of predicted values were calculated using published norms. Paired t-tests and regression analyses were used to compare gait variables. RESULTS The median age of the participants was 8 years (range 4-27) and eighteen (69.2 %) were female. Individuals with PPP2R5D-related neurodevelopmental disorder walked slower and with a wider base of support than predicted for their age and sex. Stride velocity ranged from 48.9 % to 70.1 % and stride distance from 58.5 % to 81.9 % of predicted during PPW. Percent of predicted distance walked on the 6MWT ranged from 30.6 % to 71.1 % representing varied walking impairment. Increases in stride distance, not cadence, were associated with changes in stride velocity in FPW (R2 = 0.675, p =< 0.001) and running conditions (R2 = 0.918, p =< 0.001). SIGNIFICANCE We quantitatively assessed the abnormal gait in individuals with PPP2R5D-related neurodevelopmental disorder. These impairments may affect ability to adapt to environmental changes and participation in daily life. Rehabilitative interventions targeting gait speed and balance may improve function and safety for individuals with PPP2R5D-related neurodevelopmental disorder.
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Affiliation(s)
- Kyle Zreibe
- Department of Rehabilitation, UHealth-Jackson Holtz Children's Hospital, Miami, FL, USA; Department of Rehabilitation & Regenerative Medicine, Columbia University Irving Medical Center, New York, NY, USA.
| | - Cara H Kanner
- Department of Rehabilitation & Regenerative Medicine, Columbia University Irving Medical Center, New York, NY, USA
| | - David Uher
- Department of Biobehavioral Sciences, Teachers College, Columbia University, New York, NY, USA
| | - Gabriella Beard
- Department of Rehabilitation & Regenerative Medicine, Columbia University Irving Medical Center, New York, NY, USA
| | - Madison Patterson
- Department of Rehabilitation & Regenerative Medicine, Columbia University Irving Medical Center, New York, NY, USA
| | - Matthew Harris
- Department of Rehabilitation & Regenerative Medicine, Columbia University Irving Medical Center, New York, NY, USA
| | - Jerome Doerger
- Department of Pediatrics, Columbia University Irving Medical Center, New York, NY, USA
| | - Sean Calamia
- Department of Pediatrics, Columbia University Irving Medical Center, New York, NY, USA
| | - Wendy K Chung
- Department of Pediatrics, Boston Children's Hospital, Harvard Medical School, Boston, MA USA
| | - Jacqueline Montes
- Department of Rehabilitation & Regenerative Medicine, Columbia University Irving Medical Center, New York, NY, USA
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Sudnawa KK, Chung WK. SPARKing New Insight Into Autism Across the Lifespan. AMERICAN JOURNAL ON INTELLECTUAL AND DEVELOPMENTAL DISABILITIES 2024; 129:91-95. [PMID: 38411241 DOI: 10.1352/1944-7558-129.2.91] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/28/2024]
Abstract
Autism is heterogeneous at many levels, including clinical symptoms and etiology. A key strategy in studying heterogeneous conditions is having large enough sample sizes to stratify into smaller groups that are more homogeneous. SPARK and Simons Searchlight are large and growing research cohorts of individuals with autism in the United States and individuals with genetically defined neurodevelopmental conditions around the world, respectively. They both provide freely available phenotypic and genotypic data with the ability to re-contact participants through the research match program. Deep dives into each gene in Searchlight provide comprehensive natural history data to understand the differing clinical courses to inform proper clinical care, and work toward treatment for each condition. Moreover, pilots of genetically based newborn screening programs for neurogenetic disorders can provide opportunities for equitable and early diagnosis to try to improve outcomes with earlier interventions.
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Affiliation(s)
- Khemika K Sudnawa
- Khemika K. Sudnawa, Boston Children's Hospital, Harvard Medical School and Department of Pediatrics and Pramongkutklao Hospital and Pramongkutklao College of Medicine, Bangkok, Thailand
| | - Wendy K Chung
- Wendy K. Chung, Department of Pediatrics, Boston Children's Hospital, Harvard Medical School
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Kanner CH, Uher D, Zreibe K, Beard G, Patterson M, Harris M, Doerger J, Calamia S, Chung WK, Montes J. Validation of a modified version of the gross motor function measure in PPPR5D related neurodevelopmental disorder. Orphanet J Rare Dis 2024; 19:45. [PMID: 38326877 PMCID: PMC10848481 DOI: 10.1186/s13023-024-03067-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2023] [Accepted: 02/03/2024] [Indexed: 02/09/2024] Open
Abstract
BACKGROUND Protein phosphatase 2 regulatory subunit B' Delta (PPP2R5D)-related neurodevelopmental disorder is a rare genetic condition caused by pathogenic variants in the PPP2R5D gene. Clinical signs include hypotonia, gross motor delay, intellectual disability (ID), epilepsy, speech delays, and abnormal gait among other impairments. As this disorder was recognized within the last decade, there are only 103 people published diagnoses to date. A thorough understanding of the motor manifestations of this disorder has not yet been established. Knowledge of the natural history of PPP2R5D related neurodevelopmental disorder will lead to improved standard of care treatments as well as serve as a baseline foundation for future clinical trials. Appropriate outcome measures are necessary for use in clinical trials to uniformly measure function and monitor potential for change. The aim of this study was to validate the gross motor function measure (GMFM) in children and adults with PPP2R5D-related neurodevelopmental disorder in order to better characterize the disorder. RESULTS Thirty-eight individuals with PPP2R5D pathogenic variants, median age 8.0 years (range 1-27) were evaluated. Gross motor, upper limb and ambulatory function were assessed using the GMFM-66, six-minute walk test (6MWT), 10-meter walk run (10MWR), timed up and go (TUG), and revised upper limb module (RULM). The pediatric disability inventory computer adapted test (PEDI-CAT) captured caregiver reported assessment. Median GMFM-66 score was 60.6 (SD = 17.3, range 21.1-96.0). There were strong associations between the GMFM-66 and related mobility measures, 10MWR (rs = -0.733; p < 0.001), TUG (rs= -0.747; p = 0.003), 6MWT (r = 0.633; p = 0.006), RULM (r = 0.763; p < 0.001), PEDICAT-mobility (r = 0.855; p < 0.001), and daily activities (r = 0.822; p < 0.001) domains. CONCLUSIONS The GMFM is a valid measure for characterizing motor function in individuals with PPP2R5D related neurodevelopmental disorder. The GMFM-66 had strong associations with the RULM and timed function tests which characterized gross motor, upper limb and ambulatory function demonstrating concurrent validity. The GMFM-66 was also able to differentiate between functional levels in PPP2R5D related neurodevelopmental disorder demonstrating discriminant validity. Future studies should examine its sensitivity to change over time, ability to identify sub-phenotypes, and suitability as an outcome measure in future clinical trials in individuals with PPP2R5D variants.
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Affiliation(s)
- Cara H Kanner
- Department of Rehabilitation and Regenerative Medicine, Columbia University Irving Medical Center, 617 West 168th Street, New York, NY, 10032, USA.
| | - David Uher
- Department of Rehabilitation and Regenerative Medicine, Columbia University Irving Medical Center, 617 West 168th Street, New York, NY, 10032, USA
- Department of Biobehavioral Sciences, Teachers College, Columbia University, New York, NY, USA
| | - Kyle Zreibe
- Department of Rehabilitation, UHealth-Jackson Holtz Children's Hospital, Miami, FL, USA
| | - Gabriella Beard
- Department of Rehabilitation and Regenerative Medicine, Columbia University Irving Medical Center, 617 West 168th Street, New York, NY, 10032, USA
| | - Madison Patterson
- Department of Rehabilitation and Regenerative Medicine, Columbia University Irving Medical Center, 617 West 168th Street, New York, NY, 10032, USA
| | - Matthew Harris
- Department of Rehabilitation and Regenerative Medicine, Columbia University Irving Medical Center, 617 West 168th Street, New York, NY, 10032, USA
| | - Jerome Doerger
- Department of Pediatrics, Columbia University Irving Medical Center, New York, NY, USA
| | - Sean Calamia
- Department of Pediatrics, Columbia University Irving Medical Center, New York, NY, USA
| | - Wendy K Chung
- Department of Pediatrics, Boston Children's Hospital and Harvard Medical School, Boston, MA, USA
| | - Jacqueline Montes
- Department of Rehabilitation and Regenerative Medicine, Columbia University Irving Medical Center, 617 West 168th Street, New York, NY, 10032, USA
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Wu CG, Balakrishnan VK, Merrill RA, Parihar PS, Konovolov K, Chen YC, Xu Z, Wei H, Sundaresan R, Cui Q, Wadzinski BE, Swingle MR, Musiyenko A, Chung WK, Honkanen RE, Suzuki A, Huang X, Strack S, Xing Y. B56δ long-disordered arms form a dynamic PP2A regulation interface coupled with global allostery and Jordan's syndrome mutations. Proc Natl Acad Sci U S A 2024; 121:e2310727120. [PMID: 38150499 PMCID: PMC10769853 DOI: 10.1073/pnas.2310727120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2023] [Accepted: 11/27/2023] [Indexed: 12/29/2023] Open
Abstract
Intrinsically disordered regions (IDR) and short linear motifs (SLiMs) play pivotal roles in the intricate signaling networks governed by phosphatases and kinases. B56δ (encoded by PPP2R5D) is a regulatory subunit of protein phosphatase 2A (PP2A) with long IDRs that harbor a substrate-mimicking SLiM and multiple phosphorylation sites. De novo missense mutations in PPP2R5D cause intellectual disabilities (ID), macrocephaly, Parkinsonism, and a broad range of neurological symptoms. Our single-particle cryo-EM structures of the PP2A-B56δ holoenzyme reveal that the long, disordered arms at the B56δ termini fold against each other and the holoenzyme core. This architecture suppresses both the phosphatase active site and the substrate-binding protein groove, thereby stabilizing the enzyme in a closed latent form with dual autoinhibition. The resulting interface spans over 190 Å and harbors unfavorable contacts, activation phosphorylation sites, and nearly all residues with ID-associated mutations. Our studies suggest that this dynamic interface is coupled to an allosteric network responsive to phosphorylation and altered globally by mutations. Furthermore, we found that ID mutations increase the holoenzyme activity and perturb the phosphorylation rates, and the severe variants significantly increase the mitotic duration and error rates compared to the normal variant.
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Affiliation(s)
- Cheng-Guo Wu
- McArdle Laboratory for Cancer Research, Department of Oncology, University of Wisconsin at Madison, School of Medicine and Public Health, Madison, WI53705
- Biophysics Program, University of Wisconsin at Madison, Madison, WI53706
| | - Vijaya K. Balakrishnan
- McArdle Laboratory for Cancer Research, Department of Oncology, University of Wisconsin at Madison, School of Medicine and Public Health, Madison, WI53705
| | - Ronald A. Merrill
- Department of Neuroscience and Pharmacology, University of Iowa, Iowa City, IA52242
| | - Pankaj S. Parihar
- McArdle Laboratory for Cancer Research, Department of Oncology, University of Wisconsin at Madison, School of Medicine and Public Health, Madison, WI53705
| | - Kirill Konovolov
- Chemistry Department, University of Wisconsin at Madison, Madison, WI53706
| | - Yu-Chia Chen
- McArdle Laboratory for Cancer Research, Department of Oncology, University of Wisconsin at Madison, School of Medicine and Public Health, Madison, WI53705
- Molecular and Cellular Pharmacology Program, University of Wisconsin at Madison, Madison, WI53706
| | - Zhen Xu
- Protein and Crystallography Facility, University of Iowa, Iowa City, IA52242
| | - Hui Wei
- The Simons Electron Microscopy Center, New York Structural Biology Center, New York, NY10027
| | - Ramya Sundaresan
- McArdle Laboratory for Cancer Research, Department of Oncology, University of Wisconsin at Madison, School of Medicine and Public Health, Madison, WI53705
| | - Qiang Cui
- Department of Chemistry, Boston University, Boston, MA02215
| | | | - Mark R. Swingle
- Department of Biochemistry and Molecular Biology, University of South Alabama, Mobile, AL36688
| | - Alla Musiyenko
- Department of Biochemistry and Molecular Biology, University of South Alabama, Mobile, AL36688
| | - Wendy K. Chung
- Department of Pediatrics, Boston Children’s Hospital, Harvard Medical School, Boston, MA02215
| | - Richard E. Honkanen
- Department of Biochemistry and Molecular Biology, University of South Alabama, Mobile, AL36688
| | - Aussie Suzuki
- McArdle Laboratory for Cancer Research, Department of Oncology, University of Wisconsin at Madison, School of Medicine and Public Health, Madison, WI53705
- Biophysics Program, University of Wisconsin at Madison, Madison, WI53706
- Molecular and Cellular Pharmacology Program, University of Wisconsin at Madison, Madison, WI53706
| | - Xuhui Huang
- Biophysics Program, University of Wisconsin at Madison, Madison, WI53706
- Chemistry Department, University of Wisconsin at Madison, Madison, WI53706
| | - Stefan Strack
- Department of Neuroscience and Pharmacology, University of Iowa, Iowa City, IA52242
| | - Yongna Xing
- McArdle Laboratory for Cancer Research, Department of Oncology, University of Wisconsin at Madison, School of Medicine and Public Health, Madison, WI53705
- Biophysics Program, University of Wisconsin at Madison, Madison, WI53706
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Sedlackova L, Sterbova K, Vlckova M, Seeman P, Zarubova J, Marusic P, Krsek P, Krijtova H, Musilova A, Lassuthova P. Yield of exome sequencing in patients with developmental and epileptic encephalopathies and inconclusive targeted gene panel. Eur J Paediatr Neurol 2024; 48:17-29. [PMID: 38008000 DOI: 10.1016/j.ejpn.2023.10.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/15/2022] [Revised: 10/25/2023] [Accepted: 10/28/2023] [Indexed: 11/28/2023]
Abstract
OBJECTIVE Developmental and epileptic encephalopathies (DEEs) are a group of severe, early-onset epilepsies characterised by refractory seizures, developmental delay, or regression and generally poor prognosis. DEE are now known to have an identifiable molecular genetic basis and are usually examined using a gene panel. However, for many patients, the genetic cause has still not been identified. The aims of this study were to identify causal variants for DEE in patients for whom the previous examination with a gene panel did not determine their genetic diagnosis. It also aims for a detailed description and broadening of the phenotypic spectrum of several rare DEEs. METHODS In the last five years (2015-2020), 141 patients from all over the Czech Republic were referred to our department for genetic testing in association with their diagnosis of epilepsy. All patients underwent custom-designed gene panel testing prior to enrolment into the study, and their results were inconclusive. We opted for whole exome sequencing (WES) to identify the cause of their disorder. If a causal or potentially causal variant was identified, we performed a detailed clinical evaluation and phenotype-genotype correlation study to better describe the specific rare subtypes. RESULTS Explanatory causative variants were detected in 20 patients (14%), likely pathogenic variants that explain the epilepsy in 5 patients (3.5%) and likely pathogenic variants that do not fully explain the epilepsy in 11 patients (7.5%), and variants in candidate genes in 4 patients (3%). Variants were mostly de novo 29/40 (72.5%). SIGNIFICANCE WES enables us to identify the cause of the disease in additional patients, even after gene panel testing. It is very important to perform a WES in DEE patients as soon as possible, since it will spare the patients and their families many years of a diagnostic odyssey. In particular, patients with rare epilepsies might significantly benefit from this approach, and we propose using WES as a new standard in the diagnosis of DEE instead of targeted gene panel testing.
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Affiliation(s)
- Lucie Sedlackova
- Neurogenetic Laboratory, Department of Paediatric Neurology, Second Faculty of Medicine, Charles University and Motol University Hospital, Prague, Full Member of the ERN EpiCARE, Czech Republic.
| | - Katalin Sterbova
- Department of Paediatric Neurology, Second Faculty of Medicine, Motol Epilepsy Center, Charles University and Motol University Hospital, Prague, Full Member of the ERN EpiCARE, Czech Republic.
| | - Marketa Vlckova
- Department of Biology and Medical Genetics, Second Faculty of Medicine, Charles University and Motol University Hospital, Prague, Full Member of the ERN EpiCARE, Czech Republic.
| | - Pavel Seeman
- Neurogenetic Laboratory, Department of Paediatric Neurology, Second Faculty of Medicine, Charles University and Motol University Hospital, Prague, Full Member of the ERN EpiCARE, Czech Republic; Department of Medical Genetics, Masaryk Hospital, Ústí nad Labem, Czech Republic.
| | - Jana Zarubova
- Department of Neurology, Motol Epilepsy Center, Second Faculty of Medicine, Charles University and Motol University Hospital, Prague, Full Member of the ERN EpiCARE, Czech Republic.
| | - Petr Marusic
- Department of Neurology, Motol Epilepsy Center, Second Faculty of Medicine, Charles University and Motol University Hospital, Prague, Full Member of the ERN EpiCARE, Czech Republic.
| | - Pavel Krsek
- Department of Paediatric Neurology, Second Faculty of Medicine, Motol Epilepsy Center, Charles University and Motol University Hospital, Prague, Full Member of the ERN EpiCARE, Czech Republic.
| | - Hana Krijtova
- Department of Neurology, Motol Epilepsy Center, Second Faculty of Medicine, Charles University and Motol University Hospital, Prague, Full Member of the ERN EpiCARE, Czech Republic.
| | - Alena Musilova
- Neurogenetic Laboratory, Department of Paediatric Neurology, Second Faculty of Medicine, Charles University and Motol University Hospital, Prague, Full Member of the ERN EpiCARE, Czech Republic.
| | - Petra Lassuthova
- Neurogenetic Laboratory, Department of Paediatric Neurology, Second Faculty of Medicine, Charles University and Motol University Hospital, Prague, Full Member of the ERN EpiCARE, Czech Republic.
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Alhajaj G, Lacroix C, Trakadis Y, Garfinkle J, Srour M. An in-frame deletion affecting the critical acid loop of PPP2R5D is associated with a neonatal lethal form of PPP2R5D-related neurodevelopmental disorder. Am J Med Genet A 2023; 191:2416-2421. [PMID: 37248744 DOI: 10.1002/ajmg.a.63307] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2023] [Revised: 03/31/2023] [Accepted: 05/06/2023] [Indexed: 05/31/2023]
Abstract
Heterozygous pathogenic variants in PPP2R5D gene are associated with PPP2R5D-related neurodevelopmental disorder, a rare autosomal dominant condition, characterized by neurodevelopmental impairment in childhood, macrocephaly/megalencephaly, hypotonia, epilepsy, and dysmorphic features. Up-to-date, only approximately 100 cases have been published in the literature and the full phenotypic and genotypic spectrum have not yet been fully described. PPP2R5D gene encodes the B56δ subunit of the PP2A enzyme complex. We describe a neonatal form of PPP2R5D-related disorder with early infantile death, caused by a novel in-frame deletion causing loss of 8 amino acids and insertion of serine at position 201 (p.Phe194_Pro201delinsSer) of the B56δ subunit. This deletion is predicted to disrupt a critical acidic loop of amino acids important for binding other subunits of the PP2A enzyme complex, and harbors many of the residues previously reported to cause a mild-moderate form of this condition. This report describes a neonatal lethal presentation of the PPP2R5D-related neurodevelopmental disorder and provides additional evidence that disruption of the acidic loop is an important pathomechanism underlying PPP2R5D-related disorder.
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Affiliation(s)
- Ghadd Alhajaj
- Department of Pediatrics, Unaizah College of Medicine and Medical Sciences, Qassim University, Saudi Arabia
- Department of Pediatrics, Division of Pediatric Neurology, McGill University Health Center, Montreal, Quebec, Canada
| | - Caroline Lacroix
- Department of Diagnostic Radiology, McGill University Health Center, Montreal, Quebec, Canada
| | - Yannis Trakadis
- Department of Specialized Medicine, Division of Medical Genetics, McGill University Health Center, Montreal, Quebec, Canada
| | - Jarred Garfinkle
- Department of Pediatrics, Division of Neonatology, McGill University Health Center, Montreal, Quebec, Canada
- Research Institute of the McGill University Health Centre, Montreal, Quebec, Canada
| | - Myriam Srour
- Department of Pediatrics, Division of Pediatric Neurology, McGill University Health Center, Montreal, Quebec, Canada
- Research Institute of the McGill University Health Centre, Montreal, Quebec, Canada
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Qian Y, Jiang Y, Wang J, Li G, Wu B, Zhou Y, Xu X, Wang H. Novel Variants of PPP2R1A in Catalytic Subunit Binding Domain and Genotype-Phenotype Analysis in Neurodevelopmentally Delayed Patients. Genes (Basel) 2023; 14:1750. [PMID: 37761890 PMCID: PMC10531206 DOI: 10.3390/genes14091750] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2023] [Revised: 08/26/2023] [Accepted: 08/30/2023] [Indexed: 09/29/2023] Open
Abstract
Neurodevelopmental disorders (NDDs) are a group of high-incidence rare diseases with genetic heterogeneity. PPP2R1A, the regulatory subunit of protein phosphatase 2A, is a recently discovered gene associated with NDDs. Whole/clinical exome sequencing was performed in five patients with a family with NDDs. In vitro experiments were performed to evaluate the mutants' expression and interactions with the complex. The genotype-phenotype correlations of reported cases as well as our patients with PPP2R1A variants were reviewed. We reported five unrelated individuals with PPP2R1A variants, including two novel missense variants and one frameshift variant. The protein expression of the Arg498Leu variant was less than that of the wild-type protein, the frameshift variant Asn282Argfs*14 was not decreased but truncated, and these two variants impaired the interactions with endogenous PPP25RD and PPP2CA. Furthermore, we found that pathogenic variants clustered in HEAT repeats V, VI and VII, and patients with the Met180Val/Thr variants had macrocephaly, severe ID and hypotonia, but no epilepsy, whereas those with Arg258 amino acid changes had microcephaly, while a few had epilepsy or feeding problems. In this study, we reported five NDD patients with PPP2R1A gene variants and expanded PPP2R1A pathogenic variant spectrum. The genotype and phenotype association findings provide reminders regarding the prognostication and evidence for genetic counseling.
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Affiliation(s)
- Yanyan Qian
- Center for Molecular Medicine, Pediatrics Research Institute, Children’s Hospital of Fudan University, National Children’s Medical Center, 399 Wanyuan Road, Shanghai 201102, China; (Y.Q.); (Y.J.); (G.L.); (B.W.)
| | - Yinmo Jiang
- Center for Molecular Medicine, Pediatrics Research Institute, Children’s Hospital of Fudan University, National Children’s Medical Center, 399 Wanyuan Road, Shanghai 201102, China; (Y.Q.); (Y.J.); (G.L.); (B.W.)
| | - Ji Wang
- Neurology Department, Children’s Hospital of Fudan University, National Children’s Medical Center, 399 Wanyuan Road, Shanghai 201102, China; (J.W.); (Y.Z.)
| | - Gang Li
- Center for Molecular Medicine, Pediatrics Research Institute, Children’s Hospital of Fudan University, National Children’s Medical Center, 399 Wanyuan Road, Shanghai 201102, China; (Y.Q.); (Y.J.); (G.L.); (B.W.)
| | - Bingbing Wu
- Center for Molecular Medicine, Pediatrics Research Institute, Children’s Hospital of Fudan University, National Children’s Medical Center, 399 Wanyuan Road, Shanghai 201102, China; (Y.Q.); (Y.J.); (G.L.); (B.W.)
| | - Yuanfeng Zhou
- Neurology Department, Children’s Hospital of Fudan University, National Children’s Medical Center, 399 Wanyuan Road, Shanghai 201102, China; (J.W.); (Y.Z.)
| | - Xiu Xu
- Department of Child Health Care, Children’s Hospital of Fudan University, National Children’s Medical Center, 399 Wanyuan Road, Shanghai 201102, China
| | - Huijun Wang
- Center for Molecular Medicine, Pediatrics Research Institute, Children’s Hospital of Fudan University, National Children’s Medical Center, 399 Wanyuan Road, Shanghai 201102, China; (Y.Q.); (Y.J.); (G.L.); (B.W.)
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11
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Smolen KA, Papke CM, Swingle MR, Musiyenko A, Li C, Salter EA, Camp AD, Honkanen RE, Kettenbach AN. Quantitative proteomics and phosphoproteomics of PP2A-PPP2R5D variants reveal deregulation of RPS6 phosphorylation via converging signaling cascades. J Biol Chem 2023; 299:105154. [PMID: 37572851 PMCID: PMC10485637 DOI: 10.1016/j.jbc.2023.105154] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2023] [Revised: 07/28/2023] [Accepted: 07/29/2023] [Indexed: 08/14/2023] Open
Abstract
Genetic germline variants of PPP2R5D (encoding: phosphoprotein phosphatase 2 regulatory protein 5D) result in PPP2R5D-related disorder (Jordan's Syndrome), which is characterized by intellectual disability, hypotonia, seizures, macrocephaly, autism spectrum disorder, and delayed motor skill development. The disorder originates from de novo single nucleotide mutations, generating missense variants that act in a dominant manner. Pathogenic mutations altering 13 different amino acids have been identified, with the E198K variant accounting for ∼40% of reported cases. However, the generation of a heterozygous E198K variant cell line to study the molecular effects of the pathogenic mutation has been challenging. Here, we use CRISPR-PRIME genomic editing to introduce a transition (c.592G>A) in a single PPP2R5D allele in HEK293 cells, generating E198K-heterozygous lines to complement existing E420K variant lines. We generate global protein and phosphorylation profiles of WT, E198K, and E420K cell lines and find unique and shared changes between variants and WT cells in kinase- and phosphatase-controlled signaling cascades. We observed ribosomal protein S6 (RPS6) hyperphosphorylation as a shared signaling alteration, indicative of increased ribosomal protein S6-kinase activity. Treatment with rapamycin or an RPS6-kinase inhibitor (LY2584702) suppressed RPS6 phosphorylation in both, suggesting upstream activation of mTORC1/p70S6K. Intriguingly, our data suggests ERK-dependent activation of mTORC1 in both E198K and E420K variant cells, with additional AKT-mediated mTORC1 activation in the E420K variant. Thus, although upstream activation of mTORC1 differs between PPP2R5D-related disorder genotypes, inhibition of mTORC1 or RPS6 kinases warrants further investigation as potential therapeutic strategies for patients.
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Affiliation(s)
- Kali A Smolen
- Department of Biochemistry and Cell Biology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, USA
| | - Cinta M Papke
- Department of Biochemistry and Molecular Biology, University of South Alabama, Mobile, Alabama, USA
| | - Mark R Swingle
- Department of Biochemistry and Molecular Biology, University of South Alabama, Mobile, Alabama, USA
| | - Alla Musiyenko
- Department of Biochemistry and Molecular Biology, University of South Alabama, Mobile, Alabama, USA
| | - Chenchen Li
- Department of Biochemistry and Molecular Biology, University of South Alabama, Mobile, Alabama, USA
| | - E Alan Salter
- Department of Biochemistry and Molecular Biology, University of South Alabama, Mobile, Alabama, USA
| | - Ashley D Camp
- Department of Biochemistry and Molecular Biology, University of South Alabama, Mobile, Alabama, USA
| | - Richard E Honkanen
- Department of Biochemistry and Molecular Biology, University of South Alabama, Mobile, Alabama, USA.
| | - Arminja N Kettenbach
- Department of Biochemistry and Cell Biology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, USA; Norris Cotton Cancer Center, Geisel School of Medicine at Dartmouth, Lebanon, New Hampshire, USA.
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12
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Konovalov KA, Wu CG, Qiu Y, Balakrishnan VK, Parihar PS, O’Connor MS, Xing Y, Huang X. Disease mutations and phosphorylation alter the allosteric pathways involved in autoinhibition of protein phosphatase 2A. J Chem Phys 2023; 158:215101. [PMID: 37260014 PMCID: PMC10238128 DOI: 10.1063/5.0150272] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2023] [Accepted: 05/16/2023] [Indexed: 06/02/2023] Open
Abstract
Mutations in protein phosphatase 2A (PP2A) are connected to intellectual disability and cancer. It has been hypothesized that these mutations might disrupt the autoinhibition and phosphorylation-induced activation of PP2A. Since they are located far from both the active and substrate binding sites, it is unclear how they exert their effect. We performed allosteric pathway analysis based on molecular dynamics simulations and combined it with biochemical experiments to investigate the autoinhibition of PP2A. In the wild type (WT), the C-arm of the regulatory subunit B56δ obstructs the active and substrate binding sites exerting a dual autoinhibition effect. We find that the disease mutant, E198K, severely weakens the allosteric pathways that stabilize the C-arm in the WT. Instead, the strongest allosteric pathways in E198K take a different route that promotes exposure of the substrate binding site. To facilitate the allosteric pathway analysis, we introduce a path clustering algorithm for lumping pathways into channels. We reveal remarkable similarities between the allosteric channels of E198K and those in phosphorylation-activated WT, suggesting that the autoinhibition can be alleviated through a conserved mechanism. In contrast, we find that another disease mutant, E200K, which is in spatial proximity of E198, does not repartition the allosteric pathways leading to the substrate binding site; however, it may still induce exposure of the active site. This finding agrees with our biochemical data, allowing us to predict the activity of PP2A with the phosphorylated B56δ and provide insight into how disease mutations in spatial proximity alter the enzymatic activity in surprisingly different mechanisms.
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Affiliation(s)
- Kirill A. Konovalov
- Department of Chemistry, Theoretical Chemistry Institute, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
| | | | - Yunrui Qiu
- Department of Chemistry, Theoretical Chemistry Institute, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
| | - Vijaya Kumar Balakrishnan
- McArdle Laboratory for Cancer Research, Department of Oncology, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, Wisconsin 53705, USA
| | - Pankaj Singh Parihar
- McArdle Laboratory for Cancer Research, Department of Oncology, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, Wisconsin 53705, USA
| | - Michael S. O’Connor
- Biophysics Graduate Program, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
| | - Yongna Xing
- Authors to whom correspondence should be addressed: and
| | - Xuhui Huang
- Authors to whom correspondence should be addressed: and
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13
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Fevga C, Tesson C, Carreras Mascaro A, Courtin T, van Coller R, Sakka S, Ferraro F, Farhat N, Bardien S, Damak M, Carr J, Ferrien M, Boumeester V, Hundscheid J, Grillenzoni N, Kessissoglou IA, Kuipers DJS, Quadri M, Corvol JC, Mhiri C, Hassan BA, Breedveld GJ, Lesage S, Mandemakers W, Brice A, Bonifati V. PTPA variants and impaired PP2A activity in early-onset parkinsonism with intellectual disability. Brain 2023; 146:1496-1510. [PMID: 36073231 PMCID: PMC10115167 DOI: 10.1093/brain/awac326] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2022] [Revised: 06/24/2022] [Accepted: 08/22/2022] [Indexed: 11/13/2022] Open
Abstract
The protein phosphatase 2A complex (PP2A), the major Ser/Thr phosphatase in the brain, is involved in a number of signalling pathways and functions, including the regulation of crucial proteins for neurodegeneration, such as alpha-synuclein, tau and LRRK2. Here, we report the identification of variants in the PTPA/PPP2R4 gene, encoding a major PP2A activator, in two families with early-onset parkinsonism and intellectual disability. We carried out clinical studies and genetic analyses, including genome-wide linkage analysis, whole-exome sequencing, and Sanger sequencing of candidate variants. We next performed functional studies on the disease-associated variants in cultured cells and knock-down of ptpa in Drosophila melanogaster. We first identified a homozygous PTPA variant, c.893T>G (p.Met298Arg), in patients from a South African family with early-onset parkinsonism and intellectual disability. Screening of a large series of additional families yielded a second homozygous variant, c.512C>A (p.Ala171Asp), in a Libyan family with a similar phenotype. Both variants co-segregate with disease in the respective families. The affected subjects display juvenile-onset parkinsonism and intellectual disability. The motor symptoms were responsive to treatment with levodopa and deep brain stimulation of the subthalamic nucleus. In overexpression studies, both the PTPA p.Ala171Asp and p.Met298Arg variants were associated with decreased PTPA RNA stability and decreased PTPA protein levels; the p.Ala171Asp variant additionally displayed decreased PTPA protein stability. Crucially, expression of both variants was associated with decreased PP2A complex levels and impaired PP2A phosphatase activation. PTPA orthologue knock-down in Drosophila neurons induced a significant impairment of locomotion in the climbing test. This defect was age-dependent and fully reversed by L-DOPA treatment. We conclude that bi-allelic missense PTPA variants associated with impaired activation of the PP2A phosphatase cause autosomal recessive early-onset parkinsonism with intellectual disability. Our findings might also provide new insights for understanding the role of the PP2A complex in the pathogenesis of more common forms of neurodegeneration.
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Affiliation(s)
- Christina Fevga
- Department of Clinical Genetics, Erasmus University Medical Center Rotterdam, Erasmus MC, 3015 GD Rotterdam, The Netherlands
| | - Christelle Tesson
- Institut du Cerveau - Paris Brain Institute - ICM, Inserm, CNRS, Sorbonne Université, Paris, France
| | - Ana Carreras Mascaro
- Department of Clinical Genetics, Erasmus University Medical Center Rotterdam, Erasmus MC, 3015 GD Rotterdam, The Netherlands
| | - Thomas Courtin
- Institut du Cerveau - Paris Brain Institute - ICM, Inserm, CNRS, Sorbonne Université, Paris, France
- Assistance Publique Hôpitaux de Paris, Hôpital Pitié-Salpêtrière, Département de Génétique, DMU BioGeM, Paris, France
| | - Riaan van Coller
- Department of Neurology, Faculty of Health Sciences, University of Pretoria, Pretoria, South Africa
| | - Salma Sakka
- Research Unit in Neurogenetics, Clinical Investigation Center (CIC) at the CHU Habib Bourguiba, Sfax, Tunisia
| | - Federico Ferraro
- Department of Clinical Genetics, Erasmus University Medical Center Rotterdam, Erasmus MC, 3015 GD Rotterdam, The Netherlands
| | - Nouha Farhat
- Research Unit in Neurogenetics, Clinical Investigation Center (CIC) at the CHU Habib Bourguiba, Sfax, Tunisia
| | - Soraya Bardien
- Division of Molecular Biology and Human Genetics, Faculty of Medicine and Health Sciences, Stellenbosch University, Cape Town, South Africa
- South African Medical Research Council/Stellenbosch University Genomics of Brain Disorders Research Unit, Stellenbosch University, Cape Town, South Africa
| | - Mariem Damak
- Research Unit in Neurogenetics, Clinical Investigation Center (CIC) at the CHU Habib Bourguiba, Sfax, Tunisia
| | - Jonathan Carr
- Division of Neurology, Department of Medicine, Faculty of Medicine and Health Sciences, Stellenbosch University, Cape Town, South Africa
| | - Mélanie Ferrien
- Institut du Cerveau - Paris Brain Institute - ICM, Inserm, CNRS, Sorbonne Université, Paris, France
| | - Valerie Boumeester
- Department of Clinical Genetics, Erasmus University Medical Center Rotterdam, Erasmus MC, 3015 GD Rotterdam, The Netherlands
| | - Jasmijn Hundscheid
- Department of Clinical Genetics, Erasmus University Medical Center Rotterdam, Erasmus MC, 3015 GD Rotterdam, The Netherlands
| | - Nicola Grillenzoni
- Institut du Cerveau - Paris Brain Institute - ICM, Inserm, CNRS, Sorbonne Université, Paris, France
| | - Irini A Kessissoglou
- Institut du Cerveau - Paris Brain Institute - ICM, Inserm, CNRS, Sorbonne Université, Paris, France
| | - Demy J S Kuipers
- Department of Clinical Genetics, Erasmus University Medical Center Rotterdam, Erasmus MC, 3015 GD Rotterdam, The Netherlands
| | - Marialuisa Quadri
- Department of Clinical Genetics, Erasmus University Medical Center Rotterdam, Erasmus MC, 3015 GD Rotterdam, The Netherlands
| | - Jean-Christophe Corvol
- Institut du Cerveau - Paris Brain Institute - ICM, Inserm, CNRS, Sorbonne Université, Paris, France
- Assistance Publique Hôpitaux de Paris, Hôpital Pitié-Salpêtrière, Département de Neurologie, Centre d'Investigation Clinique Neurosciences, DMU Neuroscience, Paris, France
| | - Chokri Mhiri
- Research Unit in Neurogenetics, Clinical Investigation Center (CIC) at the CHU Habib Bourguiba, Sfax, Tunisia
| | - Bassem A Hassan
- Institut du Cerveau - Paris Brain Institute - ICM, Inserm, CNRS, Sorbonne Université, Paris, France
| | - Guido J Breedveld
- Department of Clinical Genetics, Erasmus University Medical Center Rotterdam, Erasmus MC, 3015 GD Rotterdam, The Netherlands
| | - Suzanne Lesage
- Institut du Cerveau - Paris Brain Institute - ICM, Inserm, CNRS, Sorbonne Université, Paris, France
| | - Wim Mandemakers
- Department of Clinical Genetics, Erasmus University Medical Center Rotterdam, Erasmus MC, 3015 GD Rotterdam, The Netherlands
| | - Alexis Brice
- Institut du Cerveau - Paris Brain Institute - ICM, Inserm, CNRS, Sorbonne Université, Paris, France
- Assistance Publique Hôpitaux de Paris, Hôpital Pitié-Salpêtrière, Département de Génétique, DMU BioGeM, Paris, France
| | - Vincenzo Bonifati
- Department of Clinical Genetics, Erasmus University Medical Center Rotterdam, Erasmus MC, 3015 GD Rotterdam, The Netherlands
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14
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Wu CG, Balakrishnan VK, Parihar PS, Konovolov K, Chen YC, Merrill RA, Wei H, Carragher B, Sundaresan R, Cui Q, Wadzinski BE, Swingle MR, Musiyenko A, Honkanen R, Chung WK, Suzuki A, Strack S, Huang X, Xing Y. Extended regulation interface coupled to the allosteric network and disease mutations in the PP2A-B56δ holoenzyme. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.03.09.530109. [PMID: 37066309 PMCID: PMC10103954 DOI: 10.1101/2023.03.09.530109] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 06/19/2023]
Abstract
An increasing number of mutations associated with devastating human diseases are diagnosed by whole-genome/exon sequencing. Recurrent de novo missense mutations have been discovered in B56δ (encoded by PPP2R5D), a regulatory subunit of protein phosphatase 2A (PP2A), that cause intellectual disabilities (ID), macrocephaly, Parkinsonism, and a broad range of neurological symptoms. Single-particle cryo-EM structures show that the PP2A-B56δ holoenzyme possesses closed latent and open active forms. In the closed form, the long, disordered arms of B56δ termini fold against each other and the holoenzyme core, establishing dual autoinhibition of the phosphatase active site and the substrate-binding protein groove. The resulting interface spans over 190 Å and harbors unfavorable contacts, activation phosphorylation sites, and nearly all residues with ID-associated mutations. Our studies suggest that this dynamic interface is close to an allosteric network responsive to activation phosphorylation and altered globally by mutations. Furthermore, we found that ID mutations perturb the activation phosphorylation rates, and the severe variants significantly increase the mitotic duration and error rates compared to the wild variant.
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Affiliation(s)
- Cheng-Guo Wu
- McArdle Laboratory for Cancer Research, Department of Oncology, University of Wisconsin at Madison, School of Medicine and Public Health, Madison, Wisconsin 53705, USA
- Biophysics program, University of Wisconsin at Madison, Wisconsin 53706, USA
| | - Vijaya K. Balakrishnan
- McArdle Laboratory for Cancer Research, Department of Oncology, University of Wisconsin at Madison, School of Medicine and Public Health, Madison, Wisconsin 53705, USA
| | - Pankaj S. Parihar
- McArdle Laboratory for Cancer Research, Department of Oncology, University of Wisconsin at Madison, School of Medicine and Public Health, Madison, Wisconsin 53705, USA
| | - Kirill Konovolov
- Chemistry Department, University of Wisconsin at Madison, Wisconsin 53706, USA
| | - Yu-Chia Chen
- McArdle Laboratory for Cancer Research, Department of Oncology, University of Wisconsin at Madison, School of Medicine and Public Health, Madison, Wisconsin 53705, USA
- Molecular and Cellular Pharmacology program, University of Wisconsin at Madison, Wisconsin 53706, USA
| | - Ronald A Merrill
- Department of Neuroscience and Pharmacology, University of Iowa, Iowa City, IA 52242, USA
| | - Hui Wei
- New York Structural biology Center, New York, NY 10027, USA
| | | | - Ramya Sundaresan
- McArdle Laboratory for Cancer Research, Department of Oncology, University of Wisconsin at Madison, School of Medicine and Public Health, Madison, Wisconsin 53705, USA
| | - Qiang Cui
- Department of Chemistry, Metcalf Center for Science & Engineering, Boston University, Boston, MA 02215, USA
| | - Brian E. Wadzinski
- Department of Pharmacology, Vanderbilt University, Nashville, TN 37232, USA
| | - Mark R. Swingle
- Department of Biochemistry and Molecular Biology, University of South Alabama, Mobile, AL 36688, USA
| | - Alla Musiyenko
- Department of Biochemistry and Molecular Biology, University of South Alabama, Mobile, AL 36688, USA
| | - Richard Honkanen
- Department of Biochemistry and Molecular Biology, University of South Alabama, Mobile, AL 36688, USA
| | - Wendy K. Chung
- Departments of Pediatrics and Medicine, Columbia University, New York, NY 10032, USA
| | - Aussie Suzuki
- McArdle Laboratory for Cancer Research, Department of Oncology, University of Wisconsin at Madison, School of Medicine and Public Health, Madison, Wisconsin 53705, USA
- Biophysics program, University of Wisconsin at Madison, Wisconsin 53706, USA
- Department of Neuroscience and Pharmacology, University of Iowa, Iowa City, IA 52242, USA
| | - Stefan Strack
- Department of Neuroscience and Pharmacology, University of Iowa, Iowa City, IA 52242, USA
| | - Xuhui Huang
- Biophysics program, University of Wisconsin at Madison, Wisconsin 53706, USA
- Chemistry Department, University of Wisconsin at Madison, Wisconsin 53706, USA
| | - Yongna Xing
- McArdle Laboratory for Cancer Research, Department of Oncology, University of Wisconsin at Madison, School of Medicine and Public Health, Madison, Wisconsin 53705, USA
- Biophysics program, University of Wisconsin at Madison, Wisconsin 53706, USA
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15
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KA S, CM P, Swingle MR, A M, C L, AD C, RE H, AN K. Quantitative proteomics and phosphoproteomics of PPP2R5D variants reveal deregulation of RPS6 phosphorylation through converging signaling cascades. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.03.27.534397. [PMID: 37034727 PMCID: PMC10081281 DOI: 10.1101/2023.03.27.534397] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 06/19/2023]
Abstract
Variants in the phosphoprotein phosphatase-2 regulatory protein-5D gene ( PPP2R5D ) cause the clinical phenotype of Jordan's Syndrome (PPP2R5D-related disorder), which includes intellectual disability, hypotonia, seizures, macrocephaly, autism spectrum disorder and delayed motor skill development. The disorder originates from de novo single nucleotide mutations, generating missense variants that act in a dominant manner. Pathogenic mutations altering 13 different amino acids have been identified, with the E198K variant accounting for ∼40% of reported cases. Here, we use CRISPR-PRIME genomic editing to introduce a transition (c.592G>A) in the PPP2R5D allele in a heterozygous manner in HEK293 cells, generating E198K-heterozygous lines to complement existing E420K variant lines. We generate global protein and phosphorylation profiles of wild-type, E198K, and E420K cell lines and find unique and shared changes between variants and wild-type cells in kinase- and phosphatase-controlled signaling cascades. As shared signaling alterations, we observed ribosomal protein S6 (RPS6) hyperphosphorylation, indicative of increased ribosomal protein S6-kinase activity. Rapamycin treatment suppressed RPS6 phosphorylation in both, suggesting activation of mTORC1. Intriguingly, our data suggest AKT-dependent (E420K) and -independent (E198K) activation of mTORC1. Thus, although upstream activation of mTORC1 differs between PPP2R5D-related disorder genotypes, treatment with rapamycin or a p70S6K inhibitor warrants further investigation as potential therapeutic strategies for patients.
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Affiliation(s)
- Smolen KA
- Department of Biochemistry and Cell Biology, Geisel School of Medicine at Dartmouth, Hanover, NH 03755, USA
| | - Papke CM
- Department of Biochemistry and Molecular Biology, University of South Alabama, Mobile, AL 36688, USA
| | - MR Swingle
- Department of Biochemistry and Molecular Biology, University of South Alabama, Mobile, AL 36688, USA
| | - Musiyenko A
- Department of Biochemistry and Molecular Biology, University of South Alabama, Mobile, AL 36688, USA
| | - Li C
- Department of Biochemistry and Molecular Biology, University of South Alabama, Mobile, AL 36688, USA
| | - Camp AD
- Department of Biochemistry and Molecular Biology, University of South Alabama, Mobile, AL 36688, USA
| | - Honkanen RE
- Department of Biochemistry and Molecular Biology, University of South Alabama, Mobile, AL 36688, USA
| | - Kettenbach AN
- Department of Biochemistry and Cell Biology, Geisel School of Medicine at Dartmouth, Hanover, NH 03755, USA
- Norris Cotton Cancer Center, Geisel School of Medicine at Dartmouth, Lebanon, NH 03756, USA
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16
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Schwab K, Coronel L, Riege K, Sacramento EK, Rahnis N, Häckes D, Cirri E, Groth M, Hoffmann S, Fischer M. Multi-omics analysis identifies RFX7 targets involved in tumor suppression and neuronal processes. Cell Death Discov 2023; 9:80. [PMID: 36864036 PMCID: PMC9981735 DOI: 10.1038/s41420-023-01378-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2023] [Revised: 02/19/2023] [Accepted: 02/22/2023] [Indexed: 03/04/2023] Open
Abstract
Recurrently mutated in lymphoid neoplasms, the transcription factor RFX7 is emerging as a tumor suppressor. Previous reports suggested that RFX7 may also have a role in neurological and metabolic disorders. We recently reported that RFX7 responds to p53 signaling and cellular stress. Furthermore, we found RFX7 target genes to be dysregulated in numerous cancer types also beyond the hematological system. However, our understanding of RFX7's target gene network and its role in health and disease remains limited. Here, we generated RFX7 knock-out cells and employed a multi-omics approach integrating transcriptome, cistrome, and proteome data to obtain a more comprehensive picture of RFX7 targets. We identify novel target genes linked to RFX7's tumor suppressor function and underscoring its potential role in neurological disorders. Importantly, our data reveal RFX7 as a mechanistic link that enables the activation of these genes in response to p53 signaling.
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Affiliation(s)
- Katjana Schwab
- grid.418245.e0000 0000 9999 5706Computational Biology Group, Leibniz Institute on Aging—Fritz Lipmann Institute (FLI), Beutenbergstraße 11, 07745 Jena, Germany
| | - Luis Coronel
- grid.418245.e0000 0000 9999 5706Computational Biology Group, Leibniz Institute on Aging—Fritz Lipmann Institute (FLI), Beutenbergstraße 11, 07745 Jena, Germany
| | - Konstantin Riege
- grid.418245.e0000 0000 9999 5706Computational Biology Group, Leibniz Institute on Aging—Fritz Lipmann Institute (FLI), Beutenbergstraße 11, 07745 Jena, Germany
| | - Erika K. Sacramento
- grid.418245.e0000 0000 9999 5706Core Facility for Proteomics, Leibniz Institute on Aging—Fritz Lipmann Institute (FLI), Beutenbergstraße 11, 07745 Jena, Germany
| | - Norman Rahnis
- grid.418245.e0000 0000 9999 5706Core Facility for Proteomics, Leibniz Institute on Aging—Fritz Lipmann Institute (FLI), Beutenbergstraße 11, 07745 Jena, Germany
| | - David Häckes
- grid.418245.e0000 0000 9999 5706Computational Biology Group, Leibniz Institute on Aging—Fritz Lipmann Institute (FLI), Beutenbergstraße 11, 07745 Jena, Germany
| | - Emilio Cirri
- grid.418245.e0000 0000 9999 5706Core Facility for Proteomics, Leibniz Institute on Aging—Fritz Lipmann Institute (FLI), Beutenbergstraße 11, 07745 Jena, Germany
| | - Marco Groth
- grid.418245.e0000 0000 9999 5706Core Facility for Next-Generation Sequencing, Leibniz Institute on Aging—Fritz Lipmann Institute (FLI), Beutenbergstraße 11, 07745 Jena, Germany
| | - Steve Hoffmann
- grid.418245.e0000 0000 9999 5706Computational Biology Group, Leibniz Institute on Aging—Fritz Lipmann Institute (FLI), Beutenbergstraße 11, 07745 Jena, Germany
| | - Martin Fischer
- Computational Biology Group, Leibniz Institute on Aging-Fritz Lipmann Institute (FLI), Beutenbergstraße 11, 07745, Jena, Germany.
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17
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Rihar N, Krgovic D, Kokalj-Vokač N, Stangler-Herodez S, Zorc M, Dovc P. Identification of potentially pathogenic variants for autism spectrum disorders using gene-burden analysis. PLoS One 2023; 18:e0273957. [PMID: 37167322 PMCID: PMC10174571 DOI: 10.1371/journal.pone.0273957] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2022] [Accepted: 04/19/2023] [Indexed: 05/13/2023] Open
Abstract
Gene- burden analyses have lately become a very successful way for the identification of genes carrying risk variants underlying the analysed disease. This approach is also suitable for complex disorders like autism spectrum disorder (ASD). The gene-burden analysis using Testing Rare Variants with Public Data (TRAPD) software was conducted on whole exome sequencing data of Slovenian patients with ASD to determine potentially novel disease risk variants in known ASD-associated genes as well as in others. To choose the right control group for testing, principal component analysis based on the 1000 Genomes and ASD cohort samples was conducted. The subsequent protein structure and ligand binding analysis usingI-TASSER package were performed to detect changes in protein structure and ligand binding to determine a potential pathogenic consequence of observed mutation. The obtained results demonstrate an association of two variants-p.Glu198Lys (PPP2R5D:c.592G>A) and p.Arg253Gln (PPP2R5D:c.758G>A) with the ASD. Substitution p.Glu198Lys (PPP2R5D:c.592G>A) is a variant, previously described as pathogenic in association with ASD combined with intellectual disability, whereas p.Arg253Gln (PPP2R5D:c.758G>A) has not been described as an ASD-associated pathogenic variant yet. The results indicate that the filtering process was suitable and could be used in the future for detection of novel pathogenic variants when analysing groups of ASD patients.
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Affiliation(s)
- Nika Rihar
- Biotechnical Faculty, Department of Animal Science, University of Ljubljana, Ljubljana, Slovenia
| | - Danijela Krgovic
- Laboratory of Medical Genetics, University Medical Centre Maribor, Maribor, Slovenia
- Maribor Medical Faculty, University of Maribor, Maribor, Slovenia
| | - Nadja Kokalj-Vokač
- Laboratory of Medical Genetics, University Medical Centre Maribor, Maribor, Slovenia
- Maribor Medical Faculty, University of Maribor, Maribor, Slovenia
| | - Spela Stangler-Herodez
- Laboratory of Medical Genetics, University Medical Centre Maribor, Maribor, Slovenia
- Maribor Medical Faculty, University of Maribor, Maribor, Slovenia
| | - Minja Zorc
- Biotechnical Faculty, Department of Animal Science, University of Ljubljana, Ljubljana, Slovenia
| | - Peter Dovc
- Biotechnical Faculty, Department of Animal Science, University of Ljubljana, Ljubljana, Slovenia
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18
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Verbinnen I, Procknow SS, Lenaerts L, Reynhout S, Mehregan A, Ulens C, Janssens V, King KA. Clinical and molecular characteristics of a novel rare de novo variant in PPP2CA in a patient with a developmental disorder, autism, and epilepsy. Front Cell Dev Biol 2022; 10:1059938. [DOI: 10.3389/fcell.2022.1059938] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2022] [Accepted: 11/08/2022] [Indexed: 12/03/2022] Open
Abstract
PP2A-related (neuro) developmental disorders are a family of genetic diseases caused by a heterozygous alteration in one of several genes encoding a subunit of type 2A protein phosphatases. Reported affected genes, so far, are PPP2R5D, encoding the PP2A regulatory B56δ subunit; PPP2R1A, encoding the scaffolding Aα subunit; and PPP2CA, encoding the catalytic Cα subunit—in that order of frequency. Patients with a pathogenic de novo mutation in one of these genes, in part, present with overlapping features, such as generalized hypotonia, intellectual and developmental delay, facial dysmorphologies, seizures, and autistic features, and, in part, with opposite features, e.g., smaller versus larger head sizes or normal versus absent corpus callosum. Molecular variant characterization has been consistent so far with loss-of-function or dominant-negative disease mechanisms for all three affected genes. Here, we present a case report of another PPP2CA-affected individual with a novel de novo missense variant, resulting in a one-amino acid substitution in the Cα subunit: p.Cys196Arg. Biochemical characterization of the variant revealed its pathogenicity, as it appeared severely catalytically impaired, showed mildly affected A subunit binding, and moderately decreased binding to B/B55, B”/PR72, and all B56 subunits, except B56γ1. Carboxy-terminal methylation appeared unaffected, as was binding to B”’/STRN3—all being consistent with a partial loss of function. Clinically, the girl presented with mild-to-moderate developmental delay, a full-scale IQ of 83, mild dysmorphic facial features, tonic–clonic seizures, and autistic behaviors. Brain MRI appeared normal. We conclude that this individual falls within the milder end of the clinical and molecular spectrum of previously reported PPP2CA cases.
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19
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A novel nonsense mutation in PPP2R5D is associated with neurodevelopmental disorders and shows incomplete penetrance in a Chinese pedigree. Clin Neurol Neurosurg 2022; 223:107524. [DOI: 10.1016/j.clineuro.2022.107524] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2022] [Revised: 11/11/2022] [Accepted: 11/11/2022] [Indexed: 11/15/2022]
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20
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Murtaza N, Cheng AA, Brown CO, Meka DP, Hong S, Uy JA, El-Hajjar J, Pipko N, Unda BK, Schwanke B, Xing S, Thiruvahindrapuram B, Engchuan W, Trost B, Deneault E, Calderon de Anda F, Doble BW, Ellis J, Anagnostou E, Bader GD, Scherer SW, Lu Y, Singh KK. Neuron-specific protein network mapping of autism risk genes identifies shared biological mechanisms and disease-relevant pathologies. Cell Rep 2022; 41:111678. [DOI: 10.1016/j.celrep.2022.111678] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2022] [Revised: 08/16/2022] [Accepted: 10/25/2022] [Indexed: 11/23/2022] Open
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21
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Vaneynde P, Verbinnen I, Janssens V. The role of serine/threonine phosphatases in human development: Evidence from congenital disorders. Front Cell Dev Biol 2022; 10:1030119. [PMID: 36313552 PMCID: PMC9608770 DOI: 10.3389/fcell.2022.1030119] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2022] [Accepted: 09/27/2022] [Indexed: 11/23/2022] Open
Abstract
Reversible protein phosphorylation is a fundamental regulation mechanism in eukaryotic cell and organismal physiology, and in human health and disease. Until recently, and unlike protein kinases, mutations in serine/threonine protein phosphatases (PSP) had not been commonly associated with disorders of human development. Here, we have summarized the current knowledge on congenital diseases caused by mutations, inherited or de novo, in one of 38 human PSP genes, encoding a monomeric phosphatase or a catalytic subunit of a multimeric phosphatase. In addition, we highlight similar pathogenic mutations in genes encoding a specific regulatory subunit of a multimeric PSP. Overall, we describe 19 affected genes, and find that most pathogenic variants are loss-of-function, with just a few examples of gain-of-function alterations. Moreover, despite their widespread tissue expression, the large majority of congenital PSP disorders are characterised by brain-specific abnormalities, suggesting a generalized, major role for PSPs in brain development and function. However, even if the pathogenic mechanisms are relatively well understood for a small number of PSP disorders, this knowledge is still incomplete for most of them, and the further identification of downstream targets and effectors of the affected PSPs is eagerly awaited through studies in appropriate in vitro and in vivo disease models. Such lacking studies could elucidate the exact mechanisms through which these diseases act, and possibly open up new therapeutic avenues.
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Affiliation(s)
- Pieter Vaneynde
- Laboratory of Protein Phosphorylation and Proteomics, Department of Cellular and Molecular Medicine, University of Leuven (KU Leuven), Leuven, Belgium
- Leuven Brain Institute (LBI), Leuven, Belgium
| | - Iris Verbinnen
- Laboratory of Protein Phosphorylation and Proteomics, Department of Cellular and Molecular Medicine, University of Leuven (KU Leuven), Leuven, Belgium
- Leuven Brain Institute (LBI), Leuven, Belgium
| | - Veerle Janssens
- Laboratory of Protein Phosphorylation and Proteomics, Department of Cellular and Molecular Medicine, University of Leuven (KU Leuven), Leuven, Belgium
- Leuven Brain Institute (LBI), Leuven, Belgium
- *Correspondence: Veerle Janssens,
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22
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Oyama N, Vaneynde P, Reynhout S, Pao EM, Timms A, Fan X, Foss K, Derua R, Janssens V, Chung W, Mirzaa GM. Clinical, neuroimaging and molecular characteristics of PPP2R5D-related neurodevelopmental disorders: an expanded series with functional characterisation and genotype-phenotype analysis. J Med Genet 2022; 60:511-522. [PMID: 36216457 DOI: 10.1136/jmg-2022-108713] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2022] [Accepted: 09/11/2022] [Indexed: 11/03/2022]
Abstract
BACKGROUND Variants in PPP2R5D, affecting the regulatory B56δ subunit of protein phosphatase 2A (PP2A), have been identified in individuals with neurodevelopmental abnormalities. However, the molecular and clinical spectra remain incompletely understood. METHODS Individuals with PPP2R5D variants were enrolled through Simons Variation in Individuals Project/Simons Searchlight. Data were collected from medical history interviews, medical record review, online validated instruments and neuroimaging review. Genetic variants were biochemically characterised. RESULTS We studied 76 individuals with PPP2R5D variants, including 68 with pathogenic de novo variants, four with a variant of uncertain significance (VUS) and four siblings with a novel dominantly inherited pathogenic variant. Among 13 pathogenic variants, eight were novel and two (p.Glu198Lys and p.Glu200Lys) were highly recurrent. Functional analysis revealed impaired PP2A A/C-subunit binding, decreased short linear interaction motif-dependent substrate binding or both-with the most severe phenotypes associated with variants that completely retained one of these binding characteristics and lost the other-further supporting a dominant-negative disease mechanism. p.Glu198Lys showed the highest C-binding defect and a more severe clinical phenotype. The inherited p.Glu197Gly variant had a mild substrate binding defect, and three of four VUS had no biochemical impact. Common clinical phenotypes were language, intellectual or learning disabilities (80.6%), hypotonia (75.0%), macrocephaly (66.7%), seizures (45.8%) and autism spectrum disorder (26.4%). The mean composite Vineland score was 59.8, and most participants were in the 'moderate to low' and 'low' adaptive levels in all domains. CONCLUSION Our study delineates the most common features of PPP2R5D-related neurodevelopmental disorders, expands the clinical and molecular spectrum and identifies genotype-phenotype correlations.
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Affiliation(s)
- Nora Oyama
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, Washington, USA
| | - Pieter Vaneynde
- Laboratory of Protein Phosphorylation and Proteomics, Department of Cellular and Molecular Medicine, University of Leuven (KU Leuven), Leuven, Belgium.,KU Leuven Brain Institute (LBI), Leuven, Belgium
| | - Sara Reynhout
- Laboratory of Protein Phosphorylation and Proteomics, Department of Cellular and Molecular Medicine, University of Leuven (KU Leuven), Leuven, Belgium.,KU Leuven Brain Institute (LBI), Leuven, Belgium
| | - Emily M Pao
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, Washington, USA
| | - Andrew Timms
- Center for Developmental Biology and Regenerative Medicine, Seattle Children's Research Institute, Seattle, Washington, USA
| | - Xiao Fan
- Department of Pediatrics, Columbia University, New York City, New York, USA
| | - Kimberly Foss
- Department of Genetics, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Rita Derua
- Laboratory of Protein Phosphorylation and Proteomics, Department of Cellular and Molecular Medicine, University of Leuven (KU Leuven), Leuven, Belgium.,SyBioMa, University of Leuven (KU Leuven), Leuven, Belgium
| | - Veerle Janssens
- Laboratory of Protein Phosphorylation and Proteomics, Department of Cellular and Molecular Medicine, University of Leuven (KU Leuven), Leuven, Belgium.,KU Leuven Brain Institute (LBI), Leuven, Belgium
| | - Wendy Chung
- Department of Pediatrics, Columbia University, New York City, New York, USA.,Department of Medicine, Columbia University, New York City, New York, USA
| | - Ghayda M Mirzaa
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, Washington, USA .,Department of Pediatrics, University of Washington, Seattle, Washington, USA
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23
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Madaan P, Kaur A, Saini L, Paria P, Vyas S, Sharma AR, Sahu JK. PPP2R5D-Related Neurodevelopmental Disorder or Developmental and Epileptic Encephalopathy?: A Novel Phenotypic Description and Review of Published Cases. Neuropediatrics 2022; 53:20-25. [PMID: 34448180 DOI: 10.1055/s-0041-1733984] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
BACKGROUND Protein phosphatase 2 regulatory subunit B' delta (PPP2R5D)-related neurodevelopmental disorder is caused by pathogenic variations in the PPP2R5D gene, product of which is involved in dephosphorylation. This is a rare disorder with description limited to case reports. Its phenotypic spectrum has expanded over the last decade. METHODS We report a child with a developmental and epileptic encephalopathy phenotype with a pathogenic PPP2R5D variant. This phenotype has not been previously reported. We also reviewed the previously published reports of patients with this disorder. RESULTS Including the index child, 28 cases (15 girls) were identified from nine relevant research items for analysis. All patients had developmental delay. History of seizures was observed in seven patients while macrocephaly was seen in nearly 80% of patients. Nonneurological manifestations were observed in 13 patients with the most common one being ophthalmological manifestations. The most common genetic variation was c.G592A (p.E198K). The common phenotypic associations of this variation were developmental delay, macrocephaly (11/15), and epilepsy (6/15). CONCLUSION PPP2R5D gene variations should be suspected in children with developmental delay, autistic features, macrocephaly with or without epilepsy in the absence of any clear etiology. Dysmorphic features might provide a diagnostic clue. DEE phenotype may also be the presenting feature and might be an underreported entity.
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Affiliation(s)
- Priyanka Madaan
- Pediatric Neurology Unit, Department of Pediatrics, Postgraduate Institute of Medical Education and Research (PGIMER), Chandigarh, India
| | - Amrit Kaur
- Department of Pediatrics, Postgraduate Institute of Medical Education and Research (PGIMER), Chandigarh, India
| | - Lokesh Saini
- Pediatric Neurology Unit, Department of Pediatrics, Postgraduate Institute of Medical Education and Research (PGIMER), Chandigarh, India.,Department of Pediatrics, All India Institute of Medical Sciences, Jodhpur, India
| | - Pradip Paria
- Pediatric Neurology Unit, Department of Pediatrics, Postgraduate Institute of Medical Education and Research (PGIMER), Chandigarh, India
| | - Sameer Vyas
- Department of Radiodiagnosis and Imaging (Section of Neuroimaging and Interventional Radiology), Postgraduate Institute of Medical Education and Research (PGIMER), Chandigarh, India
| | - Amit R Sharma
- Department of Neurology, Postgraduate Institute of Medical Education and Research (PGIMER), Chandigarh, India
| | - Jitendra K Sahu
- Pediatric Neurology Unit, Department of Pediatrics, Postgraduate Institute of Medical Education and Research (PGIMER), Chandigarh, India
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24
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Lombardo MV, Busuoli EM, Schreibman L, Stahmer AC, Pramparo T, Landi I, Mandelli V, Bertelsen N, Barnes CC, Gazestani V, Lopez L, Bacon EC, Courchesne E, Pierce K. Pre-treatment clinical and gene expression patterns predict developmental change in early intervention in autism. Mol Psychiatry 2021; 26:7641-7651. [PMID: 34341515 PMCID: PMC8872998 DOI: 10.1038/s41380-021-01239-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/08/2021] [Revised: 06/29/2021] [Accepted: 07/13/2021] [Indexed: 12/12/2022]
Abstract
Early detection and intervention are believed to be key to facilitating better outcomes in children with autism, yet the impact of age at treatment start on the outcome is poorly understood. While clinical traits such as language ability have been shown to predict treatment outcome, whether or not and how information at the genomic level can predict treatment outcome is unknown. Leveraging a cohort of toddlers with autism who all received the same standardized intervention at a very young age and provided a blood sample, here we find that very early treatment engagement (i.e., <24 months) leads to greater gains while controlling for time in treatment. Pre-treatment clinical behavioral measures predict 21% of the variance in the rate of skill growth during early intervention. Pre-treatment blood leukocyte gene expression patterns also predict the rate of skill growth, accounting for 13% of the variance in treatment slopes. Results indicated that 295 genes can be prioritized as driving this effect. These treatment-relevant genes highly interact at the protein level, are enriched for differentially histone acetylated genes in autism postmortem cortical tissue, and are normatively highly expressed in a variety of subcortical and cortical areas important for social communication and language development. This work suggests that pre-treatment biological and clinical behavioral characteristics are important for predicting developmental change in the context of early intervention and that individualized pre-treatment biology related to histone acetylation may be key.
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Affiliation(s)
- Michael V Lombardo
- Laboratory for Autism and Neurodevelopmental Disorders, Center for Neuroscience and Cognitive Systems @UniTn, Istituto Italiano di Tecnologia, Rovereto, Italy.
- Department of Psychiatry, Autism Research Centre, University of Cambridge, Cambridge, UK.
| | - Elena Maria Busuoli
- Laboratory for Autism and Neurodevelopmental Disorders, Center for Neuroscience and Cognitive Systems @UniTn, Istituto Italiano di Tecnologia, Rovereto, Italy
- Center for Mind/Brain Sciences, University of Trento, Rovereto, Italy
| | - Laura Schreibman
- Department of Psychology, University of California, San Diego, La Jolla, CA, USA
| | - Aubyn C Stahmer
- Department of Psychiatry and Behavioral Sciences, University of California, Davis, Sacramento, CA, USA
| | - Tiziano Pramparo
- Department of Neurosciences, Autism Center of Excellence, University of California, San Diego, La Jolla, CA, USA
| | - Isotta Landi
- Laboratory for Autism and Neurodevelopmental Disorders, Center for Neuroscience and Cognitive Systems @UniTn, Istituto Italiano di Tecnologia, Rovereto, Italy
| | - Veronica Mandelli
- Laboratory for Autism and Neurodevelopmental Disorders, Center for Neuroscience and Cognitive Systems @UniTn, Istituto Italiano di Tecnologia, Rovereto, Italy
- Center for Mind/Brain Sciences, University of Trento, Rovereto, Italy
| | - Natasha Bertelsen
- Laboratory for Autism and Neurodevelopmental Disorders, Center for Neuroscience and Cognitive Systems @UniTn, Istituto Italiano di Tecnologia, Rovereto, Italy
- Center for Mind/Brain Sciences, University of Trento, Rovereto, Italy
| | - Cynthia Carter Barnes
- Department of Neurosciences, Autism Center of Excellence, University of California, San Diego, La Jolla, CA, USA
| | - Vahid Gazestani
- Department of Neurosciences, Autism Center of Excellence, University of California, San Diego, La Jolla, CA, USA
| | - Linda Lopez
- Department of Neurosciences, Autism Center of Excellence, University of California, San Diego, La Jolla, CA, USA
| | - Elizabeth C Bacon
- Department of Neurosciences, Autism Center of Excellence, University of California, San Diego, La Jolla, CA, USA
| | - Eric Courchesne
- Department of Neurosciences, Autism Center of Excellence, University of California, San Diego, La Jolla, CA, USA
| | - Karen Pierce
- Department of Neurosciences, Autism Center of Excellence, University of California, San Diego, La Jolla, CA, USA.
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25
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Maines E, Franceschi R, Martinelli D, Soli F, Lepri FR, Piccoli G, Soffiati M. Hypoglycemia due to PI3K/AKT/mTOR signaling pathway defects: two novel cases and review of the literature. Hormones (Athens) 2021; 20:623-640. [PMID: 33876391 DOI: 10.1007/s42000-021-00287-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/26/2020] [Accepted: 03/25/2021] [Indexed: 12/30/2022]
Abstract
INTRODUCTION The PI3K/AKT/mTOR signaling pathway is important for the regulation of multiple biological processes, including cellular growth and glucose metabolism. Defects of the PI3K/AKT/mTOR signaling pathway are not usually considered among the genetic causes of recurrent hypoglycemia in childhood. However, accumulating evidence links hypoglycemia with defects of this pathway. CASE REPORTS AND REVIEW We describe here two cases of macrocephaly and hypoglycemia bearing genetic defects in genes involved in the PI3K/AKT/mTOR pathway. The first patient was diagnosed with a PTEN hamartoma tumour syndrome (PTHS) due to the de novo germline missense mutation c.[492 + 1G > A] of the PTEN gene. The second patient presented the autosomal dominant mental retardation-35 (MDR35) due to the heterozygous missense mutation c.592G > A in the PPP2R5D gene. A review of the literature on hypoglycemia and PI3K/AKT/mTOR signaling pathway defects, with a special focus on the metabolic characterization of hypoglycemia, is included. CONCLUSIONS PI3K/AKT/mTOR pathway defects should be included in the differential diagnosis of patients with hypoglycemia and macrocephaly. Clinical suspicion and molecular confirmation are important, not just for an accurate genetic counselling but also for defining the follow-up management, including cancer surveillance. The biochemical profile of hypoglycemia varies among patients. While most patients are characterized by low plasmatic insulin levels, hyperinsulinemia has also been observed. Large patient cohorts are needed to gain a comprehensive profile of the biochemical patterns of hypoglycemia in such defects and eventually guide targeted therapeutic interventions.
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Affiliation(s)
- Evelina Maines
- Division of Pediatrics, S. Chiara General Hospital, Largo Medaglie d'oro, 9, 38122, Trento, Italy.
| | - Roberto Franceschi
- Division of Pediatrics, S. Chiara General Hospital, Largo Medaglie d'oro, 9, 38122, Trento, Italy
| | - Diego Martinelli
- Division of Metabolism and Research Unit of Metabolic Biochemistry, Bambino Gesù Children's Hospital, IRCCS, Rome, Italy
| | - Fiorenza Soli
- Division of Medical Genetics, S. Chiara General Hospital, Trento, Italy
| | | | - Giovanni Piccoli
- CIBIO - Centre for Integrative Biology, Università Degli Studi Di Trento, Italy & Dulbecco Telethon Institute, Trento, Italy
| | - Massimo Soffiati
- Division of Pediatrics, S. Chiara General Hospital, Largo Medaglie d'oro, 9, 38122, Trento, Italy
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26
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Fazia T, Marzanati D, Carotenuto AL, Beecham A, Hadjixenofontos A, McCauley JL, Saddi V, Piras M, Bernardinelli L, Gentilini D. Homozygosity Haplotype and Whole-Exome Sequencing Analysis to Identify Potentially Functional Rare Variants Involved in Multiple Sclerosis among Sardinian Families. Curr Issues Mol Biol 2021; 43:1778-1793. [PMID: 34889895 PMCID: PMC8929092 DOI: 10.3390/cimb43030125] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2021] [Revised: 10/13/2021] [Accepted: 10/23/2021] [Indexed: 12/24/2022] Open
Abstract
Multiple Sclerosis (MS) is a complex multifactorial autoimmune disease, whose sex- and age-adjusted prevalence in Sardinia (Italy) is among the highest worldwide. To date, 233 loci were associated with MS and almost 20% of risk heritability is attributable to common genetic variants, but many low-frequency and rare variants remain to be discovered. Here, we aimed to contribute to the understanding of the genetic basis of MS by investigating potentially functional rare variants. To this end, we analyzed thirteen multiplex Sardinian families with Immunochip genotyping data. For five families, Whole Exome Sequencing (WES) data were also available. Firstly, we performed a non-parametric Homozygosity Haplotype analysis for identifying the Region from Common Ancestor (RCA). Then, on these potential disease-linked RCA, we searched for the presence of rare variants shared by the affected individuals by analyzing WES data. We found: (i) a variant (43181034 T > G) in the splicing region on exon 27 of CUL9; (ii) a variant (50245517 A > C) in the splicing region on exon 16 of ATP9A; (iii) a non-synonymous variant (43223539 A > C), on exon 9 of TTBK1; (iv) a non-synonymous variant (42976917 A > C) on exon 9 of PPP2R5D; and v) a variant (109859349-109859354) in 3'UTR of MYO16.
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Affiliation(s)
- Teresa Fazia
- Department of Brain and Behavioral Sciences, University of Pavia, 27100 Pavia, Italy; (D.M.); (A.L.C.); (L.B.); (D.G.)
- Correspondence:
| | - Daria Marzanati
- Department of Brain and Behavioral Sciences, University of Pavia, 27100 Pavia, Italy; (D.M.); (A.L.C.); (L.B.); (D.G.)
| | - Anna Laura Carotenuto
- Department of Brain and Behavioral Sciences, University of Pavia, 27100 Pavia, Italy; (D.M.); (A.L.C.); (L.B.); (D.G.)
| | - Ashley Beecham
- John P. Hussman Institute for Human Genomics, Miller School of Medicine, University of Miami, Miami, FL 33136, USA; (A.B.); (A.H.); (J.L.M.)
- Dr. John T. Macdonald Foundation Department of Human Genetics, Miller School of Medicine, Miami, FL 33136, USA
| | - Athena Hadjixenofontos
- John P. Hussman Institute for Human Genomics, Miller School of Medicine, University of Miami, Miami, FL 33136, USA; (A.B.); (A.H.); (J.L.M.)
- Dr. John T. Macdonald Foundation Department of Human Genetics, Miller School of Medicine, Miami, FL 33136, USA
| | - Jacob L. McCauley
- John P. Hussman Institute for Human Genomics, Miller School of Medicine, University of Miami, Miami, FL 33136, USA; (A.B.); (A.H.); (J.L.M.)
- Dr. John T. Macdonald Foundation Department of Human Genetics, Miller School of Medicine, Miami, FL 33136, USA
| | - Valeria Saddi
- Divisione di Neurologia, Presidio Ospedaliero S. Francesco, ASL Numero 3 Nuoro, 08100 Nuoro, Italy; (V.S.); (M.P.)
| | - Marialuisa Piras
- Divisione di Neurologia, Presidio Ospedaliero S. Francesco, ASL Numero 3 Nuoro, 08100 Nuoro, Italy; (V.S.); (M.P.)
| | - Luisa Bernardinelli
- Department of Brain and Behavioral Sciences, University of Pavia, 27100 Pavia, Italy; (D.M.); (A.L.C.); (L.B.); (D.G.)
| | - Davide Gentilini
- Department of Brain and Behavioral Sciences, University of Pavia, 27100 Pavia, Italy; (D.M.); (A.L.C.); (L.B.); (D.G.)
- Bioinformatics and Statistical Genomics Unit, Istituto Auxologico Italiano IRCCS, 20095 Cusano Milanino, Italy
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27
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Barski MS, Minnell JJ, Maertens GN. PP2A Phosphatase as an Emerging Viral Host Factor. Front Cell Infect Microbiol 2021; 11:725615. [PMID: 34422684 PMCID: PMC8371333 DOI: 10.3389/fcimb.2021.725615] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2021] [Accepted: 07/20/2021] [Indexed: 12/12/2022] Open
Abstract
Protein phosphatase 2A (PP2A) is one of the most ubiquitous cellular proteins and is responsible for the vast majority of Ser/Thr phosphatase activity in eukaryotes. PP2A is a heterotrimer, and its assembly, intracellular localization, enzymatic activity, and substrate specificity are subject to dynamic regulation. Each of its subunits can be targeted by viral proteins to hijack and modulate its activity and downstream signaling to the advantage of the virus. Binding to PP2A is known to be essential to the life cycle of many viruses and seems to play a particularly crucial role for oncogenic viruses, which utilize PP2A to transform infected cells through controlling the cell cycle and apoptosis. Here we summarise the latest developments in the field of PP2A viral targeting; in particular recent discoveries of PP2A hijacking through molecular mimicry of a B56-specific motif by several different viruses. We also discuss the potential as well as shortcomings for therapeutic intervention in the face of our current understanding of viral PP2A targeting.
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Affiliation(s)
| | | | - Goedele Noella Maertens
- Department of Infectious Disease, Section of Molecular Virology, St Mary’s Hospital, Imperial College London, London, United Kingdom
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28
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Protein Phosphatase 2A (PP2A) mutations in brain function, development, and neurologic disease. Biochem Soc Trans 2021; 49:1567-1588. [PMID: 34241636 DOI: 10.1042/bst20201313] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2021] [Revised: 06/09/2021] [Accepted: 06/11/2021] [Indexed: 12/15/2022]
Abstract
By removing Ser/Thr-specific phosphorylations in a multitude of protein substrates in diverse tissues, Protein Phosphatase type 2A (PP2A) enzymes play essential regulatory roles in cellular signalling and physiology, including in brain function and development. Here, we review current knowledge on PP2A gene mutations causally involved in neurodevelopmental disorders and intellectual disability, focusing on PPP2CA, PPP2R1A and PPP2R5D. We provide insights into the impact of these mutations on PP2A structure, substrate specificity and potential function in neurobiology and brain development.
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29
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Sandal P, Jong CJ, Merrill RA, Song J, Strack S. Protein phosphatase 2A - structure, function and role in neurodevelopmental disorders. J Cell Sci 2021; 134:270819. [PMID: 34228795 DOI: 10.1242/jcs.248187] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Neurodevelopmental disorders (NDDs), including intellectual disability (ID), autism and schizophrenia, have high socioeconomic impact, yet poorly understood etiologies. A recent surge of large-scale genome or exome sequencing studies has identified a multitude of mostly de novo mutations in subunits of the protein phosphatase 2A (PP2A) holoenzyme that are strongly associated with NDDs. PP2A is responsible for at least 50% of total Ser/Thr dephosphorylation in most cell types and is predominantly found as trimeric holoenzymes composed of catalytic (C), scaffolding (A) and variable regulatory (B) subunits. PP2A can exist in nearly 100 different subunit combinations in mammalian cells, dictating distinct localizations, substrates and regulatory mechanisms. PP2A is well established as a regulator of cell division, growth, and differentiation, and the roles of PP2A in cancer and various neurodegenerative disorders, such as Alzheimer's disease, have been reviewed in detail. This Review summarizes and discusses recent reports on NDDs associated with mutations of PP2A subunits and PP2A-associated proteins. We also discuss the potential impact of these mutations on the structure and function of the PP2A holoenzymes and the etiology of NDDs.
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Affiliation(s)
- Priyanka Sandal
- Department of Neuroscience and Pharmacology, and Iowa Neuroscience Institute, University of Iowa, Iowa City, Iowa 52242, USA
| | - Chian Ju Jong
- Department of Neuroscience and Pharmacology, and Iowa Neuroscience Institute, University of Iowa, Iowa City, Iowa 52242, USA
| | - Ronald A Merrill
- Department of Neuroscience and Pharmacology, and Iowa Neuroscience Institute, University of Iowa, Iowa City, Iowa 52242, USA
| | - Jianing Song
- Department of Neuroscience and Pharmacology, and Iowa Neuroscience Institute, University of Iowa, Iowa City, Iowa 52242, USA
| | - Stefan Strack
- Department of Neuroscience and Pharmacology, and Iowa Neuroscience Institute, University of Iowa, Iowa City, Iowa 52242, USA
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30
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Myöhänen TT, Mertens F, Norrbacka S, Cui H. Deletion or inhibition of prolyl oligopeptidase blocks lithium-induced phosphorylation of GSK3b and Akt by activation of protein phosphatase 2A. Basic Clin Pharmacol Toxicol 2021; 129:287-296. [PMID: 34196102 DOI: 10.1111/bcpt.13632] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2021] [Revised: 06/15/2021] [Accepted: 06/27/2021] [Indexed: 11/27/2022]
Abstract
Alterations in prolyl oligopeptidase (PREP) activity have been connected, for example, with bipolar and major depressive disorder, and several studies have reported that lack or inhibition of PREP blocks the effects of lithium on inositol 1,4,5-triphosphate (IP3 ) levels. However, the impact of PREP modulation on other intracellular targets of lithium, such as glycogen synthase kinase 3 beta (GSK3b) or protein kinase B (Akt), has not been studied. We recently found that PREP regulates protein phosphatase 2A (PP2A), and because GSK3b and Akt are PP2A substrates, we studied if PREP-related lithium insensitivity is dependent on PP2A. To assess this, HEK-293 and SH-SY5Y cells with PREP deletion or PREP inhibition (KYP-2047) were exposed to lithium, and thereafter, the phosphorylation levels of GSK3b and Akt were measured by Western blot. As expected, PREP deletion and inhibition blocked the lithium-induced phosphorylation on GSK3b and Akt in both cell lines. When lithium exposure was combined with okadaic acid, a PP2A inhibitor, KYP-2047 did not have effect on lithium-induced GSK3b and Akt phosphorylation. Therefore, we conclude that PREP deletion or inhibition blocks the intracellular effects of lithium on GSK3b and Akt via PP2A activation.
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Affiliation(s)
- Timo T Myöhänen
- Division of Pharmacology and Pharmacotherapy/Drug Research Program, University of Helsinki, Helsinki, Finland.,Integrative Physiology and Pharmacology Unit, Institute of Biomedicine, University of Turku, Turku, Finland.,School of Pharmacy, Faculty of Health Sciences, University of Eastern Finland, Kuopio, Finland
| | - Freke Mertens
- Division of Pharmacology and Pharmacotherapy/Drug Research Program, University of Helsinki, Helsinki, Finland
| | - Susanna Norrbacka
- Division of Pharmacology and Pharmacotherapy/Drug Research Program, University of Helsinki, Helsinki, Finland
| | - Hengjing Cui
- Division of Pharmacology and Pharmacotherapy/Drug Research Program, University of Helsinki, Helsinki, Finland.,Department of Pharmacy, Ruijin hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China
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31
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Yan L, Shen R, Cao Z, Han C, Zhang Y, Liu Y, Yang X, Xie M, Li H. A Novel Missense Variant in the Gene PPP2R5D Causes a Rare Neurodevelopmental Disorder with Increased Phenotype. BIOMED RESEARCH INTERNATIONAL 2021; 2021:6661860. [PMID: 33628804 PMCID: PMC7895568 DOI: 10.1155/2021/6661860] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/07/2020] [Revised: 01/01/2021] [Accepted: 02/01/2021] [Indexed: 12/27/2022]
Abstract
PPP2R5D-related neurodevelopmental disorder, which is mainly caused by de novo missense variants in the PPP2R5D gene, is a rare autosomal dominant genetic disorder with about 100 patients and a total of thirteen pathogenic variants known to exist globally so far. Here, we present a 24-month-old Chinese boy with developmental delay and other common clinical characteristics of PPP2R5D-related neurodevelopmental disorder including hypotonia, macrocephaly, intellectual disability, speech impairment, and behavioral abnormality. Trio-whole exome sequencing (WES) and Sanger sequencing were performed to identify the causal gene variant. The pathogenicity of the variant was evaluated using bioinformatics tools. We identified a novel pathogenic variant in the PPP2R5D gene (c.620G>T, p.Trp207Leu). The variant is located in the variant hotspot region of this gene and is predicted to cause PPP2R5D protein dysfunction due to an increase in local hydrophobicity and unstable three-dimensional structure. We report a novel pathogenic variant of PPP2R5D associated with PPP2R5D-related neurodevelopmental disorder from a Chinese family. Our findings expanded the phenotypic and mutational spectrum of PPP2R5D-related neurodevelopmental disorder.
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Affiliation(s)
- Lulu Yan
- The Central Laboratory of Birth Defects Prevention and Control, Ningbo Women and Children's Hospital, Ningbo, Zhejiang 315012, China
| | - Ru Shen
- Department of Laboratory Medicine of Kunming Children's Hospital, Key Laboratory of Child Critical Disease Research of Yunnan Province, Kunming, Yunnan 650034, China
| | - Zongfu Cao
- National Centre for Human Genetic Resource, National Research Institute for Family Planning, Beijing 100081, China
| | - Chunxiao Han
- The Central Laboratory of Birth Defects Prevention and Control, Ningbo Women and Children's Hospital, Ningbo, Zhejiang 315012, China
| | - Yuxin Zhang
- The Central Laboratory of Birth Defects Prevention and Control, Ningbo Women and Children's Hospital, Ningbo, Zhejiang 315012, China
| | - Yingwen Liu
- The Central Laboratory of Birth Defects Prevention and Control, Ningbo Women and Children's Hospital, Ningbo, Zhejiang 315012, China
| | - Xiangchun Yang
- The Central Laboratory of Birth Defects Prevention and Control, Ningbo Women and Children's Hospital, Ningbo, Zhejiang 315012, China
| | - Min Xie
- The Central Laboratory of Birth Defects Prevention and Control, Ningbo Women and Children's Hospital, Ningbo, Zhejiang 315012, China
| | - Haibo Li
- The Central Laboratory of Birth Defects Prevention and Control, Ningbo Women and Children's Hospital, Ningbo, Zhejiang 315012, China
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32
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Papke CM, Smolen KA, Swingle MR, Cressey L, Heng RA, Toporsian M, Deng L, Hagen J, Shen Y, Chung WK, Kettenbach AN, Honkanen RE. A disorder-related variant (E420K) of a PP2A-regulatory subunit (PPP2R5D) causes constitutively active AKT-mTOR signaling and uncoordinated cell growth. J Biol Chem 2021; 296:100313. [PMID: 33482199 PMCID: PMC7952134 DOI: 10.1016/j.jbc.2021.100313] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2020] [Revised: 01/13/2021] [Accepted: 01/15/2021] [Indexed: 02/08/2023] Open
Abstract
Functional genomic approaches have facilitated the discovery of rare genetic disorders and improved efforts to decipher their underlying etiology. PPP2R5D-related disorder is an early childhood onset condition characterized by intellectual disability, hypotonia, autism-spectrum disorder, macrocephaly, and dysmorphic features. The disorder is caused by de novo single nucleotide changes in PPP2R5D, which generate heterozygous dominant missense variants. PPP2R5D is known to encode a B'-type (B'56δ) regulatory subunit of a PP2A-serine/threonine phosphatase. To help elucidate the molecular mechanisms altered in PPP2R5D-related disorder, we used a CRISPR-single-base editor to generate HEK-293 cells in which a single transition (c.1258G>A) was introduced into one allele, precisely recapitulating a clinically relevant E420K variant. Unbiased quantitative proteomic and phosphoproteomic analyses of endogenously expressed proteins revealed heterozygous-dominant changes in kinase/phosphatase signaling. These data combined with orthogonal validation studies revealed a previously unrecognized interaction of PPP2R5D with AKT in human cells, leading to constitutively active AKT-mTOR signaling, increased cell size, and uncoordinated cellular growth in E420K-variant cells. Rapamycin reduced cell size and dose-dependently reduced RPS6 phosphorylation in E420K-variant cells, suggesting that inhibition of mTOR1 can suppress both the observed RPS6 hyperphosphorylation and increased cell size. Together, our findings provide a deeper understanding of PPP2R5D and insight into how the E420K-variant alters signaling networks influenced by PPP2R5D. Our comprehensive approach, which combines precise genome editing, isobaric tandem mass tag labeling of peptides generated from endogenously expressed proteins, and concurrent liquid chromatography-mass spectrometry (LC-MS3), also provides a roadmap that can be used to rapidly explore the etiologies of additional genetic disorders.
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Affiliation(s)
- Cinta M Papke
- Department of Biochemistry and Molecular Biology, University of South Alabama, Mobile, Alabama, USA
| | - Kali A Smolen
- Department of Biochemistry and Cell Biology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, USA; Norris Cotton Cancer Center, Geisel School of Medicine at Dartmouth, Lebanon, New Hampshire, USA
| | - Mark R Swingle
- Department of Biochemistry and Molecular Biology, University of South Alabama, Mobile, Alabama, USA
| | - Lauren Cressey
- Department of Biochemistry and Cell Biology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, USA; Norris Cotton Cancer Center, Geisel School of Medicine at Dartmouth, Lebanon, New Hampshire, USA
| | - Richard A Heng
- Department of Biochemistry and Molecular Biology, University of South Alabama, Mobile, Alabama, USA
| | - Mourad Toporsian
- Department of Biochemistry and Molecular Biology, University of South Alabama, Mobile, Alabama, USA
| | - Liyong Deng
- Department of Pediatrics, Columbia University Irving Medical Center, New York, New York, USA
| | - Jacob Hagen
- Department of Pediatrics, Columbia University Irving Medical Center, New York, New York, USA
| | - Yufeng Shen
- Department of Systems Biology, Columbia University Irving Medical Center, New York, New York, USA
| | - Wendy K Chung
- Department of Pediatrics, Columbia University Irving Medical Center, New York, New York, USA; Herbert Irving Comprehensive Cancer Center, Columbia University Medical Center, New York, New York, USA; Department of Medicine, Columbia University Medical Center, New York, New York, USA
| | - Arminja N Kettenbach
- Department of Biochemistry and Cell Biology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, USA; Norris Cotton Cancer Center, Geisel School of Medicine at Dartmouth, Lebanon, New Hampshire, USA.
| | - Richard E Honkanen
- Department of Biochemistry and Molecular Biology, University of South Alabama, Mobile, Alabama, USA.
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Ziats CA, Patterson WG, Friez M. Syndromic Autism Revisited: Review of the Literature and Lessons Learned. Pediatr Neurol 2021; 114:21-25. [PMID: 33189026 DOI: 10.1016/j.pediatrneurol.2020.06.011] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/11/2020] [Revised: 05/01/2020] [Accepted: 06/19/2020] [Indexed: 11/29/2022]
Abstract
Autism spectrum disorder is a neurodevelopmental disorder characterized by deficits in communication, stereotyped behaviors, restricted interests, and impaired social skills. The severity of the neurobehavioral phenotype is variable and historically has been distinguished based on the presence or absence of additional symptoms, termed syndromic and nonsyndromic or idiopathic autism, respectively. However, although the advancement in genetic molecular technologies has brought an increased understanding of the pathophysiology of autism, most of this success has been in the diagnosis of syndromic disease, whereas the etiology of nonsyndromic autism remains less understood. Here we review the common and rare genetic syndromes that feature autism, specifically highlighting deletion and duplication syndromes, chromosomal anomalies, and monogenic disorders. We show that the study of syndromic autism provides insight into the phenotypic and molecular heterogeneity of neurodevelopmental disease and suggests how study of these disorders can be helpful in understanding disease mechanisms implicated in nonsyndromic autism.
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Affiliation(s)
- Catherine A Ziats
- Greenwood Genetic Center, J.C. Self Research Institute, Greenwood, South Carolina.
| | - Wesley G Patterson
- Greenwood Genetic Center, J.C. Self Research Institute, Greenwood, South Carolina
| | - Michael Friez
- Greenwood Genetic Center, J.C. Self Research Institute, Greenwood, South Carolina
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Hetzelt KLML, Kerling F, Kraus C, Rauch C, Thiel CT, Winterholler M, Reis A, Zweier C. Early-onset parkinsonism in PPP2R5D-related neurodevelopmental disorder. Eur J Med Genet 2020; 64:104123. [PMID: 33338668 DOI: 10.1016/j.ejmg.2020.104123] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2020] [Revised: 11/16/2020] [Accepted: 12/11/2020] [Indexed: 11/29/2022]
Abstract
PPP2R5D-related neurodevelopmental disorder (NDD) is a rare autosomal-dominant disease with developmental delay and mild to severe intellectual disability. So far, fewer than 30 affected individuals with mostly recurrent, de novo missense variants in PPP2R5D were reported. Recently, parkinsonism with an onset between 20 and 40 years was reported in four adult individuals with the same p.(Glu200Lys) variant in PPP2R5D. By trio exome sequencing we now identified the variant p.(Glu198Lys) in a 29 year old woman presenting with typical clinical manifestations of PPP2R5D-related neurodevelopmental disorder and additionally with motor decline and levodopa responsive, early-onset parkinsonism from her mid-twenties on. Accordingly, a clear reduction of dopamine transporter in the striatum on both sides was revealed by brain scintigraphy. Our findings further expand the molecular and clinical spectrum of PPP2R5D-related NDD and confirm the association with parkinsonism in early adulthood. This has marked implications for prognosis of PPP2R5D-related NDDs and for the therapeutic management of motor decline and parkinson-like symptoms in affected individuals.
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Affiliation(s)
- Katalin L M L Hetzelt
- Institute of Human Genetics, Universitätsklinikum Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg FAU, Erlangen, Germany
| | - Frank Kerling
- Department of Neurology, Epilepsy and Movement Disorders Center, Sana-Krankenhaus Rummelsberg, Schwarzenbruck/Nuremberg, Germany
| | - Cornelia Kraus
- Institute of Human Genetics, Universitätsklinikum Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg FAU, Erlangen, Germany
| | - Christophe Rauch
- Department of Neurology, Epilepsy and Movement Disorders Center, Sana-Krankenhaus Rummelsberg, Schwarzenbruck/Nuremberg, Germany
| | - Christian T Thiel
- Institute of Human Genetics, Universitätsklinikum Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg FAU, Erlangen, Germany
| | - Martin Winterholler
- Department of Neurology, Epilepsy and Movement Disorders Center, Sana-Krankenhaus Rummelsberg, Schwarzenbruck/Nuremberg, Germany
| | - André Reis
- Institute of Human Genetics, Universitätsklinikum Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg FAU, Erlangen, Germany
| | - Christiane Zweier
- Institute of Human Genetics, Universitätsklinikum Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg FAU, Erlangen, Germany.
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35
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Lenaerts L, Reynhout S, Verbinnen I, Laumonnier F, Toutain A, Bonnet-Brilhault F, Hoorne Y, Joss S, Chassevent AK, Smith-Hicks C, Loeys B, Joset P, Steindl K, Rauch A, Mehta SG, Chung WK, Devriendt K, Holder SE, Jewett T, Baldwin LM, Wilson WG, Towner S, Srivastava S, Johnson HF, Daumer-Haas C, Baethmann M, Ruiz A, Gabau E, Jain V, Varghese V, Al-Beshri A, Fulton S, Wechsberg O, Orenstein N, Prescott K, Childs AM, Faivre L, Moutton S, Sullivan JA, Shashi V, Koudijs SM, Heijligers M, Kivuva E, McTague A, Male A, van Ierland Y, Plecko B, Maystadt I, Hamid R, Hannig VL, Houge G, Janssens V. The broad phenotypic spectrum of PPP2R1A-related neurodevelopmental disorders correlates with the degree of biochemical dysfunction. Genet Med 2020; 23:352-362. [PMID: 33106617 PMCID: PMC7862067 DOI: 10.1038/s41436-020-00981-2] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2020] [Revised: 09/15/2020] [Accepted: 09/17/2020] [Indexed: 12/31/2022] Open
Abstract
Purpose Neurodevelopmental disorders (NDD) caused by protein phosphatase 2A (PP2A) dysfunction have mainly been associated with de novo variants in PPP2R5D and PPP2CA, and more rarely in PPP2R1A. Here, we aimed to better understand the latter by characterizing 30 individuals with de novo and often recurrent variants in this PP2A scaffolding Aα subunit. Methods Most cases were identified through routine clinical diagnostics. Variants were biochemically characterized for phosphatase activity and interaction with other PP2A subunits. Results We describe 30 individuals with 16 different variants in PPP2R1A, 21 of whom had variants not previously reported. The severity of developmental delay ranged from mild learning problems to severe intellectual disability (ID) with or without epilepsy. Common features were language delay, hypotonia, and hypermobile joints. Macrocephaly was only seen in individuals without B55α subunit-binding deficit, and these patients had less severe ID and no seizures. Biochemically more disruptive variants with impaired B55α but increased striatin binding were associated with profound ID, epilepsy, corpus callosum hypoplasia, and sometimes microcephaly. Conclusion We significantly expand the phenotypic spectrum of PPP2R1A-related NDD, revealing a broader clinical presentation of the patients and that the functional consequences of the variants are more diverse than previously reported.
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Affiliation(s)
- Lisa Lenaerts
- Laboratory of Protein Phosphorylation & Proteomics, Department of Cellular & Molecular Medicine, University of Leuven (KU Leuven), Leuven, Belgium
| | - Sara Reynhout
- Laboratory of Protein Phosphorylation & Proteomics, Department of Cellular & Molecular Medicine, University of Leuven (KU Leuven), Leuven, Belgium.,KU Leuven Brain Institute (LBI), Leuven, Belgium
| | - Iris Verbinnen
- Laboratory of Protein Phosphorylation & Proteomics, Department of Cellular & Molecular Medicine, University of Leuven (KU Leuven), Leuven, Belgium
| | - Frédéric Laumonnier
- UMR1253, iBrain, University of Tours, INSERM, Tours, France.,Service de Génétique, Centre Hospitalier Régional Universitaire, Tours, France
| | - Annick Toutain
- UMR1253, iBrain, University of Tours, INSERM, Tours, France.,Service de Génétique, Centre Hospitalier Régional Universitaire, Tours, France
| | - Frédérique Bonnet-Brilhault
- UMR1253, iBrain, University of Tours, INSERM, Tours, France.,Excellence Center in Autism and Neurodevelopmental Disorders, Centre Hospitalier Régional Universitaire, Tours, France
| | - Yana Hoorne
- Laboratory of Protein Phosphorylation & Proteomics, Department of Cellular & Molecular Medicine, University of Leuven (KU Leuven), Leuven, Belgium
| | - Shelagh Joss
- West of Scotland Centre for Genomic Medicine, Queen Elizabeth University Hospital, Glasgow, UK
| | | | | | - Bart Loeys
- Center for Medical Genetics, University of Antwerp/Antwerp University Hospital, Antwerp, Belgium
| | - Pascal Joset
- Institute of Medical Genetics, University of Zurich, Schlieren, Zurich, Switzerland
| | - Katharina Steindl
- Institute of Medical Genetics, University of Zurich, Schlieren, Zurich, Switzerland
| | - Anita Rauch
- Institute of Medical Genetics, University of Zurich, Schlieren, Zurich, Switzerland
| | - Sarju G Mehta
- East Anglian Regional Medical Genetics Service, Addenbrookes Hospital, Cambridge, UK
| | - Wendy K Chung
- Columbia University Medical Center, New York, NY, USA
| | - Koenraad Devriendt
- Department of Human Genetics, University of Leuven (KU Leuven), Leuven, Belgium
| | - Susan E Holder
- North West Thames Regional Genetics Service, Harrow, London, UK
| | - Tamison Jewett
- Wake Forest School of Medicine, Wake Forest University, Winston-Salem, NC, USA
| | - Lauren M Baldwin
- Wake Forest School of Medicine, Wake Forest University, Winston-Salem, NC, USA
| | - William G Wilson
- Department of Pediatrics, University of Virginia, Charlottesville, VA, USA
| | - Shelley Towner
- Department of Pediatrics, University of Virginia, Charlottesville, VA, USA
| | | | - Hannah F Johnson
- Department of Neurology, Boston Children's Hospital, Boston, MA, USA
| | | | - Martina Baethmann
- Pediatric Neurology, Sozialpädiatrisches Zentrum, Klinikum Dritter Orden München, Munich, Germany
| | - Anna Ruiz
- Genetics Laboratory, UDIAT-Centre Diagnòstic, Parc Taulí Hospital Universitari, Institut d'Investigació i Innovació Parc Taulí I3PT, Universitat Autònoma de Barcelona, Sabadell, Spain
| | - Elisabeth Gabau
- Paediatric Unit, Parc Taulí Hospital Universitari, Institut d'Investigació i Innovació Parc taulí I3PT, Universitat Autònoma de Barcelona, Sabadell, Spain
| | - Vani Jain
- All Wales Medical Genomics Service, University Hospital of Wales, Cardiff, UK
| | - Vinod Varghese
- All Wales Medical Genomics Service, University Hospital of Wales, Cardiff, UK
| | - Ali Al-Beshri
- Internal Medicine & Medical Genetics, University of Alabama at Birmingham, Birmingham, AL, USA
| | | | - Oded Wechsberg
- Pediatric Genetics Unit, Schneider Children's Medical Center of Israel, Petach Tikva, Israel.,Maccabi Healthcare Services, Tel Aviv, Israel
| | - Naama Orenstein
- Pediatric Genetics Unit, Schneider Children's Medical Center of Israel, Petach Tikva, Israel.,Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Katrina Prescott
- Yorkshire Regional Genetics Department, Leeds Teaching Hospitals NHS Trust, Leeds, UK
| | - Anne-Marie Childs
- Department of Neurology, Leeds Teaching Hospitals NHS Trust, Leeds, UK
| | - Laurence Faivre
- Centre de référence Anomalies du Développement et Syndromes malformatifs, FHU TRANSLAD, UMR1231 GAD, CHU Dijon et Université de Bourgogne, Dijon, France
| | - Sébastien Moutton
- CPDPN, Pôle mère enfant, Maison de Santé Bordeaux Bagatelle, Talence, France
| | - Jennifer A Sullivan
- Department of Pediatrics, Division of Medical Genetics, Duke University Medical Center, Durham, NC, USA
| | - Vandana Shashi
- Department of Pediatrics, Division of Medical Genetics, Duke University Medical Center, Durham, NC, USA
| | | | - Malou Heijligers
- Department of Clinical Genetics, Maastricht UMC+, Maastricht, The Netherlands
| | - Emma Kivuva
- Royal Devon & Exeter NHS Foundation Trust, Exeter, UK
| | - Amy McTague
- Developmental Neurosciences, UCL Great Ormond Street Institute of Child Health, London, UK.,Department of Neurology, Great Ormond Street Hospital, London, UK
| | - Alison Male
- Developmental Neurosciences, UCL Great Ormond Street Institute of Child Health, London, UK.,Department of Neurology, Great Ormond Street Hospital, London, UK
| | | | - Barbara Plecko
- Division of General Pediatrics, Department of Pediatrics and Adolescent Medicine, Medical University of Graz, Graz, Austria
| | - Isabelle Maystadt
- Centre de Génétique Humaine, Institut de Pathologie et de Génétique, Gosselies, Belgium
| | - Rizwan Hamid
- Vanderbilt University Medical Center, Nashville, TN, USA
| | | | - Gunnar Houge
- Department of Medical Genetics, Haukeland University Hospital, Bergen, Norway.
| | - Veerle Janssens
- Laboratory of Protein Phosphorylation & Proteomics, Department of Cellular & Molecular Medicine, University of Leuven (KU Leuven), Leuven, Belgium. .,KU Leuven Brain Institute (LBI), Leuven, Belgium.
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36
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Christensen KR, Nairn AC. cAMP-regulated phosphoproteins DARPP-32, ARPP16/19, and RCS modulate striatal signal transduction through protein kinases and phosphatases. ADVANCES IN PHARMACOLOGY (SAN DIEGO, CALIF.) 2020; 90:39-65. [PMID: 33706938 DOI: 10.1016/bs.apha.2020.09.005] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Decades of research led by Paul Greengard identified protein phosphorylation as a ubiquitous and vital post-translational modification involved in many neuronal signaling pathways. In particular, his discovery that second messenger-regulated protein phosphorylation plays a central role in the propagation and transduction of signals in the nervous system has been essential in understanding the molecular mechanisms of neuronal communication. The establishment of dopamine (DA) as an essential neurotransmitter in the central nervous system, combined with observations that DA activates G-protein-coupled receptors to control the production of cyclic adenosine monophosphate (cAMP) in postsynaptic neurons, has provided fundamental insight into the regulation of neurotransmission. Notably, DA signaling in the striatum is involved in many neurological functions such as control of locomotion, reward, addiction, and learning, among others. This review focuses on the history, characterization, and function of cAMP-mediated regulation of serine/threonine protein phosphatases and their role in DA-mediated signaling in striatal neurons. Several small, heat- and acid-stable proteins, including DARPP-32, RCS, and ARPP-16/19, were discovered by the Greengard laboratory to be regulated by DA- and cAMP signaling, and found to undergo a complex but coordinated sequence of phosphorylation and dephosphorylation events. These studies have contributed significantly to the establishment of protein phosphorylation as a ubiquitous and vital process in signal propagation in neurons, paradigm shifting discoveries at the time. Understanding DA-mediated signaling in the context of signal propagation has led to numerous insights into human conditions and the development of treatments and therapies.
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Affiliation(s)
- Kyle R Christensen
- Department of Psychiatry, Yale University, School of Medicine, New Haven, CT, United States
| | - Angus C Nairn
- Department of Psychiatry, Yale University, School of Medicine, New Haven, CT, United States.
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37
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Kim CY, Wirth T, Hubsch C, Németh AH, Okur V, Anheim M, Drouot N, Tranchant C, Rudolf G, Chelly J, Tatton-Brown K, Blauwendraat C, Vonsattel JPG, Cortes E, Alcalay RN, Chung WK. Early-Onset Parkinsonism Is a Manifestation of the PPP2R5D p.E200K Mutation. Ann Neurol 2020; 88:1028-1033. [PMID: 32743835 DOI: 10.1002/ana.25863] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2020] [Revised: 07/29/2020] [Accepted: 07/30/2020] [Indexed: 12/21/2022]
Abstract
PPP2R5D-related neurodevelopmental disorder is characterized by a range of neurodevelopmental and behavioral manifestations. We report the association of early-onset parkinsonism with the PPP2R5D p.E200K mutation. Clinical characterization and exome sequencing were performed on three patients, with postmortem neuropathologic examination for one patient. All patients had mild developmental delay and developed levodopa-responsive parkinsonism between the ages of 25 and 40 years. The PPP2R5D c.598G>A (p.E200K) mutation was identified in all patients. Neuropathologic examination demonstrated uneven, focally severe neuronal loss and gliosis in the substantia nigra pars compacta, without Lewy bodies. Our findings suggest the PPP2R5D p.E200K mutation to be a possible new cause of early-onset parkinsonism. ANN NEUROL 2020;88:1028-1033.
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Affiliation(s)
- Christine Y Kim
- Department of Neurology, Yale School of Medicine, Yale University, New Haven, CT, USA.,Center for Neuroepidemiology and Clinical Neurological Research, Yale School of Medicine, Yale University, New Haven, CT, USA
| | - Thomas Wirth
- Unit of Functional Neurosurgery, National Hospital for Neurology and Neurosurgery, University College London Hospital, London, UK.,Service de Neurologie, Hôpitaux Universitaires de Strasbourg, Strasbourg, France.,Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), INSERM-U964/CNRS-UMR7104/Université de Strasbourg, Illkirch-Graffenstaden, France
| | - Cécile Hubsch
- Fondation Ophtalmologique A. de Rothschild, Paris, France
| | - Andrea H Németh
- Oxford University Hospitals NHS Trust and University of Oxford, Oxford, UK
| | - Volkan Okur
- Department of Pediatrics, College of Physicians and Surgeons, Columbia University, New York, NY, USA
| | - Mathieu Anheim
- Service de Neurologie, Hôpitaux Universitaires de Strasbourg, Strasbourg, France.,Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), INSERM-U964/CNRS-UMR7104/Université de Strasbourg, Illkirch-Graffenstaden, France.,Fédération de Médecine Translationnelle de Strasbourg, Strasbourg, France
| | - Nathalie Drouot
- Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), INSERM-U964/CNRS-UMR7104/Université de Strasbourg, Illkirch-Graffenstaden, France
| | - Christine Tranchant
- Service de Neurologie, Hôpitaux Universitaires de Strasbourg, Strasbourg, France.,Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), INSERM-U964/CNRS-UMR7104/Université de Strasbourg, Illkirch-Graffenstaden, France.,Fédération de Médecine Translationnelle de Strasbourg, Strasbourg, France
| | - Gabrielle Rudolf
- Service de Neurologie, Hôpitaux Universitaires de Strasbourg, Strasbourg, France.,Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), INSERM-U964/CNRS-UMR7104/Université de Strasbourg, Illkirch-Graffenstaden, France.,Fédération de Médecine Translationnelle de Strasbourg, Strasbourg, France
| | - Jamel Chelly
- Service de Neurologie, Hôpitaux Universitaires de Strasbourg, Strasbourg, France.,Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), INSERM-U964/CNRS-UMR7104/Université de Strasbourg, Illkirch-Graffenstaden, France.,Laboratoire de diagnostic génétique, Hôpitaux Universitaires de Strasbourg, Strasbourg, France
| | | | - Cornelis Blauwendraat
- Laboratory of Neurogenetics, National Institute on Aging, National Institutes of Health, Bethesda, MD, USA
| | - Jean Paul G Vonsattel
- Department of Pathology and Cell Biology, Columbia University Medical Center and the New York Presbyterian Hospital, New York, NY, USA
| | - Etty Cortes
- Department of Pathology, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Roy N Alcalay
- Department of Neurology, College of Physicians and Surgeons, Columbia University, New York, NY, USA.,Taub Institute for Research on Alzheimer's Disease and the Aging Brain, Columbia University, New York, NY, USA
| | - Wendy K Chung
- Department of Pediatrics, College of Physicians and Surgeons, Columbia University, New York, NY, USA.,Department of Medicine, College of Physicians and Surgeons, Columbia University, New York, NY, USA
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38
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Genç Ö, An JY, Fetter RD, Kulik Y, Zunino G, Sanders SJ, Davis GW. Homeostatic plasticity fails at the intersection of autism-gene mutations and a novel class of common genetic modifiers. eLife 2020; 9:55775. [PMID: 32609087 PMCID: PMC7394548 DOI: 10.7554/elife.55775] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2020] [Accepted: 06/07/2020] [Indexed: 01/08/2023] Open
Abstract
We identify a set of common phenotypic modifiers that interact with five independent autism gene orthologs (RIMS1, CHD8, CHD2, WDFY3, ASH1L) causing a common failure of presynaptic homeostatic plasticity (PHP) in Drosophila. Heterozygous null mutations in each autism gene are demonstrated to have normal baseline neurotransmission and PHP. However, PHP is sensitized and rendered prone to failure. A subsequent electrophysiology-based genetic screen identifies the first known heterozygous mutations that commonly genetically interact with multiple ASD gene orthologs, causing PHP to fail. Two phenotypic modifiers identified in the screen, PDPK1 and PPP2R5D, are characterized. Finally, transcriptomic, ultrastructural and electrophysiological analyses define one mechanism by which PHP fails; an unexpected, maladaptive up-regulation of CREG, a conserved, neuronally expressed, stress response gene and a novel repressor of PHP. Thus, we define a novel genetic landscape by which diverse, unrelated autism risk genes may converge to commonly affect the robustness of synaptic transmission.
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Affiliation(s)
- Özgür Genç
- Department of Biochemistry and Biophysics Kavli Institute for Fundamental Neuroscience University of California, San Francisco, San Francisco, United States
| | - Joon-Yong An
- Department of Psychiatry UCSF Weill Institute for Neurosciences University of California, San Francisco, San Francisco, United States.,School of Biosystem and Biomedical Science, College of Health Science, Korea University, Seoul, Republic of Korea
| | - Richard D Fetter
- Department of Biochemistry and Biophysics Kavli Institute for Fundamental Neuroscience University of California, San Francisco, San Francisco, United States
| | - Yelena Kulik
- Department of Biochemistry and Biophysics Kavli Institute for Fundamental Neuroscience University of California, San Francisco, San Francisco, United States
| | - Giulia Zunino
- Department of Biochemistry and Biophysics Kavli Institute for Fundamental Neuroscience University of California, San Francisco, San Francisco, United States
| | - Stephan J Sanders
- Department of Psychiatry UCSF Weill Institute for Neurosciences University of California, San Francisco, San Francisco, United States
| | - Graeme W Davis
- Department of Biochemistry and Biophysics Kavli Institute for Fundamental Neuroscience University of California, San Francisco, San Francisco, United States
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39
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Jong CJ, Merrill RA, Wilkerson EM, Herring LE, Graves LM, Strack S. Reduction of protein phosphatase 2A (PP2A) complexity reveals cellular functions and dephosphorylation motifs of the PP2A/B'δ holoenzyme. J Biol Chem 2020; 295:5654-5668. [PMID: 32156701 PMCID: PMC7186168 DOI: 10.1074/jbc.ra119.011270] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2019] [Revised: 02/21/2020] [Indexed: 12/17/2022] Open
Abstract
Protein phosphatase 2A (PP2A) is a large enzyme family responsible for most cellular Ser/Thr dephosphorylation events. PP2A substrate specificity, localization, and regulation by second messengers rely on more than a dozen regulatory subunits (including B/R2, B'/R5, and B″/R3), which form the PP2A heterotrimeric holoenzyme by associating with a dimer comprising scaffolding (A) and catalytic (C) subunits. Because of partial redundancy and high endogenous expression of PP2A holoenzymes, traditional approaches of overexpressing, knocking down, or knocking out PP2A regulatory subunits have yielded only limited insights into their biological roles and substrates. To this end, here we sought to reduce the complexity of cellular PP2A holoenzymes. We used tetracycline-inducible expression of pairs of scaffolding and regulatory subunits with complementary charge-reversal substitutions in their interaction interfaces. For each of the three regulatory subunit families, we engineered A/B charge-swap variants that could bind to one another, but not to endogenous A and B subunits. Because endogenous Aα was targeted by a co-induced shRNA, endogenous B subunits were rapidly degraded, resulting in expression of predominantly a single PP2A heterotrimer composed of the A/B charge-swap pair and the endogenous catalytic subunit. Using B'δ/PPP2R5D, we show that PP2A complexity reduction, but not PP2A overexpression, reveals a role of this holoenzyme in suppression of extracellular signal-regulated kinase signaling and protein kinase A substrate dephosphorylation. When combined with global phosphoproteomics, the PP2A/B'δ reduction approach identified consensus dephosphorylation motifs in its substrates and suggested that residues surrounding the phosphorylation site play roles in PP2A substrate specificity.
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Affiliation(s)
- Chian Ju Jong
- Department of Neuroscience and Pharmacology and Iowa Neuroscience Institute, University of Iowa, Iowa City, Iowa 52242
| | - Ronald A Merrill
- Department of Neuroscience and Pharmacology and Iowa Neuroscience Institute, University of Iowa, Iowa City, Iowa 52242
| | - Emily M Wilkerson
- Michael Hooker Proteomics Facility, University of North Carolina, Chapel Hill, North Carolina 27516
| | - Laura E Herring
- Michael Hooker Proteomics Facility, University of North Carolina, Chapel Hill, North Carolina 27516
| | - Lee M Graves
- Michael Hooker Proteomics Facility, University of North Carolina, Chapel Hill, North Carolina 27516
| | - Stefan Strack
- Department of Neuroscience and Pharmacology and Iowa Neuroscience Institute, University of Iowa, Iowa City, Iowa 52242.
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40
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Huang C, Liu T, Wang Q, Hou W, Zhou C, Song Z, Shi YS, Gao X, Chen G, Yin Z, Hu Y. Loss of PP2A Disrupts the Retention of Radial Glial Progenitors in the Telencephalic Niche to Impair the Generation for Late-Born Neurons During Cortical Development†. Cereb Cortex 2020; 30:4183-4196. [PMID: 32186707 DOI: 10.1093/cercor/bhaa042] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Telencephalic radial glial progenitors (RGPs) are retained in the ventricular zone (VZ), the niche for neural stem cells during cortical development. However, the underlying mechanism is not well understood. To study whether protein phosphatase 2A (PP2A) may regulate the above process, we generate Ppp2cα conditional knockout (cKO) mice, in which PP2A catalytic subunit α (PP2Acα) is inactivated in neural progenitor cells in the dorsal telencephalon. We show that RGPs are ectopically distributed in cortical areas outside of the VZ in Ppp2cα cKO embryos. Whereas deletion of PP2Acα does not affect the proliferation of RGPs, it significantly impairs the generation of late-born neurons. We find complete loss of apical adherens junctions (AJs) in the ventricular membrane in Ppp2cα cKO cortices. We observe abundant colocalization for N-cadherin and PP2Acα in control AJs. Moreover, in vitro analysis reveals direct interactions of N-cadherin to PP2Acα and to β-catenin. Overall, this study not only uncovers a novel function of PP2Acα in retaining RGPs into the VZ but also demonstrates the impact of PP2A-dependent retention of RGPs on the generation for late-born neurons.
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Affiliation(s)
- Chaoli Huang
- State Key Laboratory of Pharmaceutical Biotechnology, MOE Key Laboratory of Model Animal for Disease Study, Model Animal Research Center, Institute for Brain Sciences, Nanjing University, Nanjing 210061, China
| | - Tingting Liu
- State Key Laboratory of Pharmaceutical Biotechnology, MOE Key Laboratory of Model Animal for Disease Study, Model Animal Research Center, Institute for Brain Sciences, Nanjing University, Nanjing 210061, China
| | - Qihui Wang
- State Key Laboratory of Pharmaceutical Biotechnology, MOE Key Laboratory of Model Animal for Disease Study, Model Animal Research Center, Institute for Brain Sciences, Nanjing University, Nanjing 210061, China
| | - Weikang Hou
- State Key Laboratory of Pharmaceutical Biotechnology, MOE Key Laboratory of Model Animal for Disease Study, Model Animal Research Center, Institute for Brain Sciences, Nanjing University, Nanjing 210061, China
| | - Cuihua Zhou
- Department of Anesthesiology, The Second Affiliated Changzhou People's Hospital of Nanjing Medical University, Changzhou 213000, China
| | - Zeyuan Song
- Department of Anesthesiology, The Second Affiliated Changzhou People's Hospital of Nanjing Medical University, Changzhou 213000, China
| | - Yun Stone Shi
- State Key Laboratory of Pharmaceutical Biotechnology, MOE Key Laboratory of Model Animal for Disease Study, Model Animal Research Center, Institute for Brain Sciences, Nanjing University, Nanjing 210061, China
| | - Xiang Gao
- State Key Laboratory of Pharmaceutical Biotechnology, MOE Key Laboratory of Model Animal for Disease Study, Model Animal Research Center, Institute for Brain Sciences, Nanjing University, Nanjing 210061, China
| | - Guiquan Chen
- State Key Laboratory of Pharmaceutical Biotechnology, MOE Key Laboratory of Model Animal for Disease Study, Model Animal Research Center, Institute for Brain Sciences, Nanjing University, Nanjing 210061, China
| | - Zhenyu Yin
- Department of Geriatric, Nanjing Drum Tower Hospital, Nanjing University Medical School, Nanjing 210008, China
| | - Yimin Hu
- Department of Anesthesiology, The Second Affiliated Changzhou People's Hospital of Nanjing Medical University, Changzhou 213000, China
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41
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Kurtz-Nelson EC, Beighley JS, Hudac CM, Gerdts J, Wallace AS, Hoekzema K, Eichler EE, Bernier RA. Co-occurring medical conditions among individuals with ASD-associated disruptive mutations. CHILDRENS HEALTH CARE 2020; 49:361-384. [PMID: 33727758 DOI: 10.1080/02739615.2020.1741361] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Children with autism spectrum disorder (ASD) are at risk for co-occurring medical conditions, many of which have also been reported among individuals with mutations in ASD-associated genes. This study examined rates of co-occurring medical conditions across 301 individuals with disruptive mutations to 1 of 18 ASD-risk genes in comparison to rates of conditions in an idiopathic ASD sample. Rates of gastrointestinal problems, seizures, physical anomalies, and immune problems were generally elevated, with significant differences in rates observed between groups. Results may inform medical care of individuals with ASD-associated mutations and research into mechanisms of co-occurring medical conditions in ASD.
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Affiliation(s)
| | - Jennifer S Beighley
- Department of Psychiatry and Behavioral Sciences, University of Washington, Seattle, WA 98195, USA
| | - Caitlin M Hudac
- Center for Youth Development and Interventions, Department of Psychology, University of Alabama, Tuscaloosa, AL 35401
| | - Jennifer Gerdts
- Department of Psychiatry and Behavioral Sciences, University of Washington, Seattle, WA 98195, USA
| | - Arianne S Wallace
- Department of Psychiatry and Behavioral Sciences, University of Washington, Seattle, WA 98195, USA
| | - Kendra Hoekzema
- Department of Genome Sciences, University of Washington School of Medicine, Seattle, WA 98195, USA
| | - Evan E Eichler
- Department of Genome Sciences, University of Washington School of Medicine, Seattle, WA 98195, USA.,Howard Hughes Medical Institute, Seattle, WA 98195, USA
| | - Raphael A Bernier
- Department of Psychiatry and Behavioral Sciences, University of Washington, Seattle, WA 98195, USA
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42
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Biswas D, Cary W, Nolta JA. PPP2R5D-Related Intellectual Disability and Neurodevelopmental Delay: A Review of the Current Understanding of the Genetics and Biochemical Basis of the Disorder. Int J Mol Sci 2020; 21:ijms21041286. [PMID: 32074998 PMCID: PMC7072873 DOI: 10.3390/ijms21041286] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2019] [Revised: 02/03/2020] [Accepted: 02/10/2020] [Indexed: 12/14/2022] Open
Abstract
Protein Phosphatase 2 Regulatory Subunit B′ Delta (PPP2R5D)-related intellectual disability (ID) and neurodevelopmental delay results from germline de novo mutations in the PPP2R5D gene. This gene encodes the protein PPP2R5D (also known as the B56 delta subunit), which is an isoform of the subunit family B56 of the enzyme serine/threonine-protein phosphatase 2A (PP2A). Clinical signs include intellectual disability (ID); autism spectrum disorder (ASD); epilepsy; speech problems; behavioral challenges; and ophthalmologic, skeletal, endocrine, cardiac, and genital malformations. The association of defective PP2A activity in the brain with a wide range of severity of ID, along with its role in ASD, Alzheimer’s disease, and Parkinson’s-like symptoms, have recently generated the impetus for further research into mutations within this gene. PP2A, together with protein phosphatase 1 (PP1), accounts for more than 90% of all phospho-serine/threonine dephosphorylations in different tissues. The specificity for a wide variety of substrates is determined through nearly 100 different PP2A holoenzymes that are formed by at least 23 types of regulatory B subunits, and two isoforms each of the catalytic subunit C and the structural subunit A. In the mammalian brain, PP2A-mediated protein dephosphorylation plays an important role in learning and memory. The PPP2R5D subunit is highly expressed in the brain and the PPP2A–PPP2R5D holoenzyme plays an important role in maintaining neurons and regulating neuronal signaling. From 2015 to 2017, 25 individuals with PPP2R5D-related developmental disorder were diagnosed. Since then, Whole-Exome Sequencing (WES) has helped to identify more unrelated individuals clinically diagnosed with a neurodevelopmental disorder with pathological variants of PPP2R5D. In this review, we discuss the current understanding of the clinical and genetic aspects of the disorder in the context of the known functions of the PP2A–PPP2R5D holoenzyme in the brain, as well as the pathogenic mutations in PPP2R5D that lead to deficient PP2A–PPP2R5D dephosphorylation and their implications during development and in the etiology of autism, Parkinson’s disease, Alzheimer’s disease, and so forth. In the future, tools such as transgenic animals carrying pathogenic PPP2R5D mutations, and patient-derived induced pluripotent stem cell lines need to be developed in order to fully understand the effects of these mutations on different neural cell types.
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Affiliation(s)
- Dayita Biswas
- SPARK Program Scholar, Institute for Regenerative Cures, University of California, Sacramento, CA 95817, USA;
| | - Whitney Cary
- Stem Cell Program, UC Davis School of Medicine. The University of California, Sacramento, CA 95817, USA
- UC Davis Gene Therapy Program, University of California, Sacramento, CA 95817, USA
- Correspondence: (W.C.); (J.A.N.)
| | - Jan A. Nolta
- SPARK Program Scholar, Institute for Regenerative Cures, University of California, Sacramento, CA 95817, USA;
- Stem Cell Program, UC Davis School of Medicine. The University of California, Sacramento, CA 95817, USA
- UC Davis Gene Therapy Program, University of California, Sacramento, CA 95817, USA
- Correspondence: (W.C.); (J.A.N.)
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43
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Kumar P, Tathe P, Chaudhary N, Maddika S. PPM1G forms a PPP-type phosphatase holoenzyme with B56δ that maintains adherens junction integrity. EMBO Rep 2019; 20:e46965. [PMID: 31432583 PMCID: PMC6776900 DOI: 10.15252/embr.201846965] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2018] [Revised: 07/26/2019] [Accepted: 08/02/2019] [Indexed: 12/11/2022] Open
Abstract
Serine/threonine phosphatases achieve substrate diversity by forming distinct holoenzyme complexes in cells. Although the PPP family of serine/threonine phosphatase family members such as PP1 and PP2A are well known to assemble and function as holoenzymes, none of the PPM family members were so far shown to act as holoenzymes. Here, we provide evidence that PPM1G, a member of PPM family of serine/threonine phosphatases, forms a distinct holoenzyme complex with the PP2A regulatory subunit B56δ. B56δ promotes the re-localization of PPM1G to the cytoplasm where the phosphatase can access a discrete set of substrates. Further, we unveil α-catenin, a component of adherens junction, as a new substrate for the PPM1G-B56 phosphatase complex in the cytoplasm. B56δ-PPM1G dephosphorylates α-catenin at serine 641, which is necessary for the appropriate assembly of adherens junctions and the prevention of aberrant cell migration. Collectively, we reveal a new holoenzyme with PPM1G-B56δ as integral components, in which the regulatory subunit provides accessibility to distinct substrates for the phosphatase by defining its cellular localization.
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Affiliation(s)
- Parveen Kumar
- Laboratory of Cell Death & Cell SurvivalCentre for DNA Fingerprinting and Diagnostics (CDFD)Uppal, HyderabadIndia
- Graduate StudiesManipal Academy of Higher EducationManipalIndia
| | - Prajakta Tathe
- Laboratory of Cell Death & Cell SurvivalCentre for DNA Fingerprinting and Diagnostics (CDFD)Uppal, HyderabadIndia
- Graduate StudiesManipal Academy of Higher EducationManipalIndia
| | - Neelam Chaudhary
- Laboratory of Cell Death & Cell SurvivalCentre for DNA Fingerprinting and Diagnostics (CDFD)Uppal, HyderabadIndia
| | - Subbareddy Maddika
- Laboratory of Cell Death & Cell SurvivalCentre for DNA Fingerprinting and Diagnostics (CDFD)Uppal, HyderabadIndia
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44
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Pirozzi F, Nelson B, Mirzaa G. From microcephaly to megalencephaly: determinants of brain size. DIALOGUES IN CLINICAL NEUROSCIENCE 2019. [PMID: 30936767 PMCID: PMC6436952 DOI: 10.31887/dcns.2018.20.4/gmirzaa] [Citation(s) in RCA: 49] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/02/2022]
Abstract
Expansion of the human brain, and specifically the neocortex, is among the most remarkable evolutionary processes that correlates with cognitive, emotional, and social abilities. Cortical expansion is determined through a tightly orchestrated process of neural stem cell proliferation, migration, and ongoing organization, synaptogenesis, and apoptosis. Perturbations of each of these intricate steps can lead to abnormalities of brain size in humans, whether small (microcephaly) or large (megalencephaly). Abnormalities of brain growth can be clinically isolated or occur as part of complex syndromes associated with other neurodevelopmental problems (eg, epilepsy, autism, intellectual disability), brain malformations, and body growth abnormalities. Thorough review of the genetic literature reveals that human microcephaly and megalencephaly are caused by mutations of a rapidly growing number of genes linked within critical cellular pathways that impact early brain development, with important pathomechanistic links to cancer, body growth, and epilepsy. Given the rapid rate of causal gene identification for microcephaly and megalencephaly understanding the roles and interplay of these important signaling pathways is crucial to further unravel the mechanisms underlying brain growth disorders and, more fundamentally, normal brain growth and development in humans. In this review, we will (a) overview the definitions of microcephaly and megalencephaly, highlighting their classifications in clinical practice; (b) overview the most common genes and pathways underlying microcephaly and megalencephaly based on the fundamental cellular processes that are perturbed during cortical development; and (c) outline general clinical molecular diagnostic workflows for children and adults presenting with microcephaly and megalencephaly.
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Affiliation(s)
- Filomena Pirozzi
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, Washington, USA
| | - Branden Nelson
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, Washington, USA
| | - Ghayda Mirzaa
- Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, Washington, USA; Division of Genetic Medicine, Department of Pediatrics, University of Washington, Seattle, Washington, USA
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45
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Lecoquierre F, Duffourd Y, Vitobello A, Bruel AL, Urteaga B, Coubes C, Garret P, Nambot S, Chevarin M, Jouan T, Moutton S, Tran-Mau-Them F, Philippe C, Sorlin A, Faivre L, Thauvin-Robinet C. Variant recurrence in neurodevelopmental disorders: the use of publicly available genomic data identifies clinically relevant pathogenic missense variants. Genet Med 2019; 21:2504-2511. [DOI: 10.1038/s41436-019-0518-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2019] [Accepted: 04/12/2019] [Indexed: 12/19/2022] Open
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46
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Reynhout S, Jansen S, Haesen D, van Belle S, de Munnik SA, Bongers EM, Schieving JH, Marcelis C, Amiel J, Rio M, Mclaughlin H, Ladda R, Sell S, Kriek M, Peeters-Scholte CM, Terhal PA, van Gassen KL, Verbeek N, Henry S, Scott Schwoerer J, Malik S, Revencu N, Ferreira CR, Macnamara E, Braakman HM, Brimble E, Ruzhnikov MR, Wagner M, Harrer P, Wieczorek D, Kuechler A, Tziperman B, Barel O, de Vries BB, Gordon CT, Janssens V, Vissers LE. De Novo Mutations Affecting the Catalytic Cα Subunit of PP2A, PPP2CA, Cause Syndromic Intellectual Disability Resembling Other PP2A-Related Neurodevelopmental Disorders. Am J Hum Genet 2019; 104:139-156. [PMID: 30595372 DOI: 10.1016/j.ajhg.2018.12.002] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2018] [Accepted: 12/06/2018] [Indexed: 12/11/2022] Open
Abstract
Type 2A protein phosphatases (PP2As) are highly expressed in the brain and regulate neuronal signaling by catalyzing phospho-Ser/Thr dephosphorylations in diverse substrates. PP2A holoenzymes comprise catalytic C-, scaffolding A-, and regulatory B-type subunits, which determine substrate specificity and physiological function. Interestingly, de novo mutations in genes encoding A- and B-type subunits have recently been implicated in intellectual disability (ID) and developmental delay (DD). We now report 16 individuals with mild to profound ID and DD and a de novo mutation in PPP2CA, encoding the catalytic Cα subunit. Other frequently observed features were severe language delay (71%), hypotonia (69%), epilepsy (63%), and brain abnormalities such as ventriculomegaly and a small corpus callosum (67%). Behavioral problems, including autism spectrum disorders, were reported in 47% of individuals, and three individuals had a congenital heart defect. PPP2CA de novo mutations included a partial gene deletion, a frameshift, three nonsense mutations, a single amino acid duplication, a recurrent mutation, and eight non-recurrent missense mutations. Functional studies showed complete PP2A dysfunction in four individuals with seemingly milder ID, hinting at haploinsufficiency. Ten other individuals showed mutation-specific biochemical distortions, including poor expression, altered binding to the A subunit and specific B-type subunits, and impaired phosphatase activity and C-terminal methylation. Four were suspected to have a dominant-negative mechanism, which correlated with severe ID. Two missense variants affecting the same residue largely behaved as wild-type in our functional assays. Overall, we found that pathogenic PPP2CA variants impair PP2A-B56(δ) functionality, suggesting that PP2A-related neurodevelopmental disorders constitute functionally converging ID syndromes.
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Leslie SN, Nairn AC. cAMP regulation of protein phosphatases PP1 and PP2A in brain. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2018; 1866:64-73. [PMID: 30401536 DOI: 10.1016/j.bbamcr.2018.09.006] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 09/02/2018] [Accepted: 09/13/2018] [Indexed: 12/21/2022]
Abstract
Normal functioning of the brain is dependent upon a complex web of communication between numerous cell types. Within neuronal networks, the faithful transmission of information between neurons relies on an equally complex organization of inter- and intra-cellular signaling systems that act to modulate protein activity. In particular, post-translational modifications (PTMs) are responsible for regulating protein activity in response to neurochemical signaling. The key second messenger, cyclic adenosine 3',5'-monophosphate (cAMP), regulates one of the most ubiquitous and influential PTMs, phosphorylation. While cAMP is canonically viewed as regulating the addition of phosphate groups through its activation of cAMP-dependent protein kinases, it plays an equally critical role in regulating removal of phosphate through indirect control of protein phosphatase activity. This dichotomy of regulation by cAMP places it as one of the key regulators of protein activity in response to neuronal signal transduction throughout the brain. In this review we focus on the role of cAMP in regulation of the serine/threonine phosphatases protein phosphatase 1 (PP1) and protein phosphatase 2A (PP2A) and the relevance of control of PP1 and PP2A to regulation of brain function and behavior.
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Affiliation(s)
- Shannon N Leslie
- Interdepartmental Neuroscience Program, Yale University, New Haven, CT, United States of America
| | - Angus C Nairn
- Department of Psychiatry, Yale University, New Haven, CT, United States of America
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Huckins LM, Hatzikotoulas K, Southam L, Thornton LM, Steinberg J, Aguilera-McKay F, Treasure J, Schmidt U, Gunasinghe C, Romero A, Curtis C, Rhodes D, Moens J, Kalsi G, Dempster D, Leung R, Keohane A, Burghardt R, Ehrlich S, Hebebrand J, Hinney A, Ludolph A, Walton E, Deloukas P, Hofman A, Palotie A, Palta P, van Rooij FJA, Stirrups K, Adan R, Boni C, Cone R, Dedoussis G, van Furth E, Gonidakis F, Gorwood P, Hudson J, Kaprio J, Kas M, Keski-Rahonen A, Kiezebrink K, Knudsen GP, Slof-Op 't Landt MCT, Maj M, Monteleone AM, Monteleone P, Raevuori AH, Reichborn-Kjennerud T, Tozzi F, Tsitsika A, van Elburg A, Collier DA, Sullivan PF, Breen G, Bulik CM, Zeggini E. Investigation of common, low-frequency and rare genome-wide variation in anorexia nervosa. Mol Psychiatry 2018; 23:1169-1180. [PMID: 29155802 PMCID: PMC5828108 DOI: 10.1038/mp.2017.88] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/03/2016] [Revised: 02/16/2017] [Accepted: 02/17/2017] [Indexed: 12/12/2022]
Abstract
Anorexia nervosa (AN) is a complex neuropsychiatric disorder presenting with dangerously low body weight, and a deep and persistent fear of gaining weight. To date, only one genome-wide significant locus associated with AN has been identified. We performed an exome-chip based genome-wide association studies (GWAS) in 2158 cases from nine populations of European origin and 15 485 ancestrally matched controls. Unlike previous studies, this GWAS also probed association in low-frequency and rare variants. Sixteen independent variants were taken forward for in silico and de novo replication (11 common and 5 rare). No findings reached genome-wide significance. Two notable common variants were identified: rs10791286, an intronic variant in OPCML (P=9.89 × 10-6), and rs7700147, an intergenic variant (P=2.93 × 10-5). No low-frequency variant associations were identified at genome-wide significance, although the study was well-powered to detect low-frequency variants with large effect sizes, suggesting that there may be no AN loci in this genomic search space with large effect sizes.
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Affiliation(s)
- L M Huckins
- Department of Human Genetics, Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge, UK
- Division of Psychiatric Genomics, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - K Hatzikotoulas
- Department of Human Genetics, Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge, UK
| | - L Southam
- Department of Human Genetics, Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge, UK
| | - L M Thornton
- Department of Psychiatry and Nutrition, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - J Steinberg
- Department of Human Genetics, Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge, UK
| | - F Aguilera-McKay
- Department of Human Genetics, Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge, UK
| | - J Treasure
- Section of Eating Disorders, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK
| | - U Schmidt
- Section of Eating Disorders, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK
| | - C Gunasinghe
- Section of Eating Disorders, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK
- NIHR BRC SLaM BioResource for Mental Health, SGDP Centre & Centre for Neuroimaging Sciences, Section of Eating Disorders, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK
| | - A Romero
- Section of Eating Disorders, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK
- NIHR BRC SLaM BioResource for Mental Health, SGDP Centre & Centre for Neuroimaging Sciences, Section of Eating Disorders, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK
| | - C Curtis
- Section of Eating Disorders, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK
- NIHR BRC SLaM BioResource for Mental Health, SGDP Centre & Centre for Neuroimaging Sciences, Section of Eating Disorders, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK
| | - D Rhodes
- Section of Eating Disorders, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK
- NIHR BRC SLaM BioResource for Mental Health, SGDP Centre & Centre for Neuroimaging Sciences, Section of Eating Disorders, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK
| | - J Moens
- Section of Eating Disorders, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK
- NIHR BRC SLaM BioResource for Mental Health, SGDP Centre & Centre for Neuroimaging Sciences, Section of Eating Disorders, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK
| | - G Kalsi
- Section of Eating Disorders, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK
- NIHR BRC SLaM BioResource for Mental Health, SGDP Centre & Centre for Neuroimaging Sciences, Section of Eating Disorders, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK
| | - D Dempster
- Section of Eating Disorders, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK
- NIHR BRC SLaM BioResource for Mental Health, SGDP Centre & Centre for Neuroimaging Sciences, Section of Eating Disorders, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK
| | - R Leung
- Section of Eating Disorders, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK
- NIHR BRC SLaM BioResource for Mental Health, SGDP Centre & Centre for Neuroimaging Sciences, Section of Eating Disorders, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK
| | - A Keohane
- Section of Eating Disorders, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK
- NIHR BRC SLaM BioResource for Mental Health, SGDP Centre & Centre for Neuroimaging Sciences, Section of Eating Disorders, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK
| | - R Burghardt
- Klinik für Kinder- und Jugendpsychiatrie, Psychotherapie und Psychosomatik Klinikum Frankfurt, Frankfurt, Germany
| | - S Ehrlich
- Division of Psychological and Social Medicine and Developmental Neurosciences, Faculty of Medicine, TU Dresden, Dresden, Germany
- Eating Disorders Research and Treatment Center, Department of Child and Adolescent Psychiatry, Faculty of Medicine, TU Dresden, Dresden, Germany
| | - J Hebebrand
- Department of Child and Adolescent Psychiatry and Psychotherapy, University Hospital Essen, University of Duisburg-Essen, Essen, Germany
| | - A Hinney
- Department of Child and Adolescent Psychiatry and Psychotherapy, University Hospital Essen, University of Duisburg-Essen, Essen, Germany
| | - A Ludolph
- Helmholtz Zentrum München, Deutsches Forschungszentrum für Gesundheit und Umwelt, Neuherberg, Germany
| | - E Walton
- Division of Psychological & Social Medicine and Developmental Neurosciences, Technische Universität Dresden, Faculty of Medicine, University Hospital C.G. Carus, Dresden, Germany
- Department of Psychology, Georgia State University, Atlanta, GA, USA
| | - P Deloukas
- Department of Human Genetics, Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge, UK
| | - A Hofman
- Erasmus University Medical Center, Rotterdam, The Netherlands
| | - A Palotie
- Center for Human Genome Research at the Massachusetts General Hospital, Boston, MA, USA
- Department of Public Health & Institute for Molecular Medicine FIMM, University of Helsinki, Helsinki, Finland
| | - P Palta
- Department of Public Health & Institute for Molecular Medicine FIMM, University of Helsinki, Helsinki, Finland
| | - F J A van Rooij
- Erasmus University Medical Center, Rotterdam, The Netherlands
| | - K Stirrups
- Department of Human Genetics, Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge, UK
| | - R Adan
- Brain Center Rudolf Magnus, Department of Neuroscience and Pharmacology, University Medical Center Utrecht, Utrecht, The Netherlands
| | - C Boni
- INSERM U984, Centre of Psychiatry and Neuroscience, Paris, France
| | - R Cone
- Mary Sue Coleman Director, Life Sciences Institute, Professor of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI, USA
| | - G Dedoussis
- Department of Dietetics-Nutrition, Harokopio University, Athens, Greece
| | - E van Furth
- Rivierduinen Eating Disorders Ursula, Leiden, Zuid-Holland, The Netherlands
| | - F Gonidakis
- Eating Disorders Unit, 1st Department of Psychiatry, National and Kapodistrian University of Athens, Medical School, Athens, Greece
| | - P Gorwood
- INSERM U984, Centre of Psychiatry and Neuroscience, Paris, France
| | - J Hudson
- Department of Psychiatry, McLean Hospital/Harvard Medical School, Belmont, MA, USA
| | - J Kaprio
- Department of Public Health & Institute for Molecular Medicine FIMM, University of Helsinki, Helsinki, Finland
| | - M Kas
- Groningen Institute for Evolutionary Life Sciences, University of Groningen, Groningen, The Netherlands
| | - A Keski-Rahonen
- Department of Public Health, Clinicum, University of Helsinki, Helsinki, Finland
| | - K Kiezebrink
- Institute of Applied Health Sciences, University of Aberdeen, Aberdeen, UK
| | - G-P Knudsen
- Health Data and Digitalisation, Norwegian Institute of Public Health, Oslo, Norway
| | | | - M Maj
- Department of Psychiatry, University of Naples SUN, Naples, Italy
| | - A M Monteleone
- Department of Psychiatry, University of Naples SUN, Naples, Italy
| | - P Monteleone
- Department of Medicine and Surgery, Section of Neurosciences, University of Salerno, Salerno, Italy
| | - A H Raevuori
- Department of Public Health, Clinicum, University of Helsinki, Helsinki, Finland
| | - T Reichborn-Kjennerud
- Department of Genetics, Environment and Mental Health, Norwegian Institute of Public Health, Oslo, Norway
| | - F Tozzi
- eHealth Lab-Computer Science Department, University of Cyprus, Nicosia, Cyprus
| | - A Tsitsika
- Adolescent Health Unit (A.H.U.), 2nd Department of Pediatrics – Medical School, University of Athens "P. & A. Kyriakou" Children's Hospital, Athens, Greece
| | - A van Elburg
- Center for Eating Disorders Rintveld, University of Utrecht, Utrecht, The Netherlands
| | - D A Collier
- Eli Lilly and Company, Erl Wood Manor, Windlesham, UK
| | - P F Sullivan
- Departments of Genetics and Psychiatry, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Department of Medical Epidemiology and Biostatistics, Karolinksa Institutet, Stockholm, Sweden
| | - G Breen
- Social Genetic and Developmental Psychiatry, King's College London, London, UK
| | - C M Bulik
- Department of Psychiatry and Nutrition, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
- Department of Medical Epidemiology and Biostatistics, Karolinksa Institutet, Stockholm, Sweden
| | - E Zeggini
- Department of Human Genetics, Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge, UK
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Methylation-regulated decommissioning of multimeric PP2A complexes. Nat Commun 2017; 8:2272. [PMID: 29273778 PMCID: PMC5741625 DOI: 10.1038/s41467-017-02405-3] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2017] [Accepted: 11/28/2017] [Indexed: 11/09/2022] Open
Abstract
Dynamic assembly/disassembly of signaling complexes are crucial for cellular functions. Specialized latency and activation chaperones control the biogenesis of protein phosphatase 2A (PP2A) holoenzymes that contain a common scaffold and catalytic subunits and a variable regulatory subunit. Here we show that the butterfly-shaped TIPRL (TOR signaling pathway regulator) makes highly integrative multibranching contacts with the PP2A catalytic subunit, selective for the unmethylated tail and perturbing/inactivating the phosphatase active site. TIPRL also makes unusual wobble contacts with the scaffold subunit, allowing TIPRL, but not the overlapping regulatory subunits, to tolerate disease-associated PP2A mutations, resulting in reduced holoenzyme assembly and enhanced inactivation of mutant PP2A. Strikingly, TIPRL and the latency chaperone, α4, coordinate to disassemble active holoenzymes into latent PP2A, strictly controlled by methylation. Our study reveals a mechanism for methylation-responsive inactivation and holoenzyme disassembly, illustrating the complexity of regulation/signaling, dynamic complex disassembly, and disease mutations in cancer and intellectual disability.
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50
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Yeung KS, Tso WWY, Ip JJK, Mak CCY, Leung GKC, Tsang MHY, Ying D, Pei SLC, Lee SL, Yang W, Chung BHY. Identification of mutations in the PI3K-AKT-mTOR signalling pathway in patients with macrocephaly and developmental delay and/or autism. Mol Autism 2017; 8:66. [PMID: 29296277 PMCID: PMC5738835 DOI: 10.1186/s13229-017-0182-4] [Citation(s) in RCA: 69] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2017] [Accepted: 12/11/2017] [Indexed: 01/12/2023] Open
Abstract
Background Macrocephaly, which is defined as a head circumference greater than or equal to + 2 standard deviations, is a feature commonly observed in children with developmental delay and/or autism spectrum disorder. Although PTEN is a well-known gene identified in patients with this syndromic presentation, other genes in the PI3K-AKT-mTOR signalling pathway have also recently been suggested to have important roles. The aim of this study is to characterise the mutation spectrum of this group of patients. Methods We performed whole-exome sequencing of 21 patients with macrocephaly and developmental delay/autism spectrum disorder. Sources of genomic DNA included blood, buccal mucosa and saliva. Germline mutations were validated by Sanger sequencing, whereas somatic mutations were validated by droplet digital PCR. Results We identified ten pathogenic/likely pathogenic mutations in PTEN (n = 4), PIK3CA (n = 3), MTOR (n = 1) and PPP2R5D (n = 2) in ten patients. An additional PTEN mutation, which was classified as variant of unknown significance, was identified in a patient with a pathogenic PTEN mutation, making him harbour bi-allelic germline PTEN mutations. Two patients harboured somatic PIK3CA mutations, and the level of somatic mosaicism in blood DNA was low. Patients who tested positive for mutations in the PI3K-AKT-mTOR pathway had a lower developmental quotient than the rest of the cohort (DQ = 62.8 vs. 76.1, p = 0.021). Their dysmorphic features were non-specific, except for macrocephaly. Among the ten patients with identified mutations, brain magnetic resonance imaging was performed in nine, all of whom showed megalencephaly. Conclusion We identified mutations in the PI3K-AKT-mTOR signalling pathway in nearly half of our patients with macrocephaly and developmental delay/autism spectrum disorder. These patients have subtle dysmorphic features and mild developmental issues. Clinically, patients with germline mutations are difficult to distinguish from patients with somatic mutations, and therefore, sequencing of buccal or saliva DNA is important to identify somatic mosaicism. Given the high diagnostic yield and the management implications, we suggest implementing comprehensive genetic testing in the PI3K-AKT-mTOR pathway in the clinical evaluation of patients with macrocephaly and developmental delay and/or autism spectrum disorder. Electronic supplementary material The online version of this article (10.1186/s13229-017-0182-4) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Kit San Yeung
- Department of Paediatrics and Adolescent Medicine, The University of Hong Kong, Pok Fu Lam, Hong Kong, China
| | - Winnie Wan Yee Tso
- Department of Paediatrics and Adolescent Medicine, The University of Hong Kong, Pok Fu Lam, Hong Kong, China.,Department of Paediatrics and Adolescent Medicine, The Duchess of Kent Children's Hospital, Pok Fu Lam, Hong Kong, China
| | - Janice Jing Kun Ip
- Department of Radiology, Queen Mary Hospital, Room 103, New Clinical Building, 102 Pokfulam Road, Pok Fu Lam, Hong Kong, China
| | - Christopher Chun Yu Mak
- Department of Paediatrics and Adolescent Medicine, The University of Hong Kong, Pok Fu Lam, Hong Kong, China
| | - Gordon Ka Chun Leung
- Department of Paediatrics and Adolescent Medicine, The University of Hong Kong, Pok Fu Lam, Hong Kong, China
| | - Mandy Ho Yin Tsang
- Department of Paediatrics and Adolescent Medicine, The University of Hong Kong, Pok Fu Lam, Hong Kong, China
| | - Dingge Ying
- Department of Paediatrics and Adolescent Medicine, The University of Hong Kong, Pok Fu Lam, Hong Kong, China
| | - Steven Lim Cho Pei
- Department of Paediatrics and Adolescent Medicine, The University of Hong Kong, Pok Fu Lam, Hong Kong, China
| | - So Lun Lee
- Department of Paediatrics and Adolescent Medicine, The University of Hong Kong, Pok Fu Lam, Hong Kong, China.,Department of Paediatrics and Adolescent Medicine, The Duchess of Kent Children's Hospital, Pok Fu Lam, Hong Kong, China
| | - Wanling Yang
- Department of Paediatrics and Adolescent Medicine, The University of Hong Kong, Pok Fu Lam, Hong Kong, China
| | - Brian Hon-Yin Chung
- Department of Paediatrics and Adolescent Medicine, The University of Hong Kong, Pok Fu Lam, Hong Kong, China.,Department of Paediatrics and Adolescent Medicine, The Duchess of Kent Children's Hospital, Pok Fu Lam, Hong Kong, China.,Department of Radiology, Queen Mary Hospital, Room 103, New Clinical Building, 102 Pokfulam Road, Pok Fu Lam, Hong Kong, China
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