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Burnett SB, Culver AM, Simon TA, Rowson T, Frederick K, Palmer K, Murray SA, Davis SW, Patel RC. A frameshift mutation in the murine Prkra gene causes dystonia and exhibits abnormal cerebellar development and reduced eIF2α phosphorylation. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.06.04.597421. [PMID: 38895245 PMCID: PMC11185611 DOI: 10.1101/2024.06.04.597421] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/21/2024]
Abstract
Mutations in Prkra gene, which encodes PACT/RAX cause early onset primary dystonia DYT-PRKRA, a movement disorder that disrupts coordinated muscle movements. PACT/RAX activates protein kinase R (PKR, aka EIF2AK2) by a direct interaction in response to cellular stressors to mediate phosphorylation of the α subunit of the eukaryotic translation initiation factor 2 (eIF2α). Mice homozygous for a naturally arisen, recessively inherited frameshift mutation, Prkra lear-5J exhibit progressive dystonia. In the present study, we investigate the biochemical and developmental consequences of the Prkra lear-5J mutation. Our results indicate that the truncated PACT/RAX protein retains its ability to interact with PKR, however, it inhibits PKR activation. Furthermore, mice homozygous for the mutation have abnormalities in the cerebellar development as well as a severe lack of dendritic arborization of Purkinje neurons. Additionally, reduced eIF2α phosphorylation is noted in the cerebellums and Purkinje neurons of the homozygous Prkra lear-5J mice. These results indicate that PACT/RAX mediated regulation of PKR activity and eIF2α phosphorylation plays a role in cerebellar development and contributes to the dystonia phenotype resulting from this mutation.
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Affiliation(s)
| | | | | | | | | | - Kristina Palmer
- The Jackson Laboratory, 600 Main St., Bar Harbor, ME 04609, USA
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2
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Matar E, Bhatia K. Dystonia and Parkinson's disease: Do they have a shared biology? INTERNATIONAL REVIEW OF NEUROBIOLOGY 2023; 169:347-411. [PMID: 37482398 DOI: 10.1016/bs.irn.2023.05.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/25/2023]
Abstract
Parkinsonism and dystonia co-occur across many movement disorders and are most encountered in the setting of Parkinson's disease. Here we aim to explore the shared neurobiological underpinnings of dystonia and parkinsonism through the clinical lens of the conditions in which these movement disorders can be seen together. Foregrounding the discussion, we briefly review the circuits of the motor system and the neuroanatomical and neurophysiological aspects of motor control and highlight their relevance to the proposed pathophysiology of parkinsonism and dystonia. Insight into shared biology is then sought from dystonia occurring in PD and other forms of parkinsonism including those disorders in which both can be co-expressed simultaneously. We organize these within a biological schema along with important questions to be addressed in this space.
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Affiliation(s)
- Elie Matar
- UCL Queen Square Institute of Neurology Department of Clinical and Movement Neurosciences, Queen Square, London, United Kingdom; Central Clinical School, Faculty of Medicine and Health, University of Sydney, Sydney, Australia.
| | - Kailash Bhatia
- UCL Queen Square Institute of Neurology Department of Clinical and Movement Neurosciences, Queen Square, London, United Kingdom
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Frederick K, Patel RC. Luteolin protects DYT- PRKRA cells from apoptosis by suppressing PKR activation. Front Pharmacol 2023; 14:1118725. [PMID: 36874028 PMCID: PMC9974672 DOI: 10.3389/fphar.2023.1118725] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2022] [Accepted: 02/06/2023] [Indexed: 02/17/2023] Open
Abstract
DYT-PRKRA is a movement disorder caused by mutations in the PRKRA gene, which encodes for PACT, the protein activator of interferon-induced, double-stranded RNA (dsRNA)-activated protein kinase PKR. PACT brings about PKR's catalytic activation by a direct binding in response to stress signals and activated PKR phosphorylates the translation initiation factor eIF2α. Phosphorylation of eIF2α is the central regulatory event that is part of the integrated stress response (ISR), an evolutionarily conserved intracellular signaling network essential for adapting to environmental stresses to maintain healthy cells. A dysregulation of either the level or the duration of eIF2α phosphorylation in response to stress signals causes the normally pro-survival ISR to become pro-apoptotic. Our research has established that the PRKRA mutations reported to cause DYT-PRKRA lead to enhanced PACT-PKR interactions causing a dysregulation of ISR and an increased sensitivity to apoptosis. We have previously identified luteolin, a plant flavonoid, as an inhibitor of the PACT-PKR interaction using high-throughput screening of chemical libraries. Our results presented in this study indicate that luteolin is markedly effective in disrupting the pathological PACT-PKR interactions to protect DYT-PRKRA cells against apoptosis, thus suggesting a therapeutic option for using luteolin to treat DYT-PRKRA and possibly other diseases resulting from enhanced PACT-PKR interactions.
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Affiliation(s)
- Kenneth Frederick
- Department of Biological Sciences, University of South Carolina, Columbia, SC, United States
| | - Rekha C Patel
- Department of Biological Sciences, University of South Carolina, Columbia, SC, United States
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Vaughn LS, Frederick K, Burnett SB, Sharma N, Bragg DC, Camargos S, Cardoso F, Patel RC. DYT- PRKRA Mutation P222L Enhances PACT's Stimulatory Activity on Type I Interferon Induction. Biomolecules 2022; 12:713. [PMID: 35625640 PMCID: PMC9138762 DOI: 10.3390/biom12050713] [Citation(s) in RCA: 2] [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: 04/11/2022] [Revised: 05/10/2022] [Accepted: 05/13/2022] [Indexed: 12/10/2022] Open
Abstract
DYT-PRKRA (dystonia 16 or DYT-PRKRA) is caused by mutations in the PRKRA gene that encodes PACT, the protein activator of interferon (IFN)-induced double-stranded (ds) RNA-activated protein kinase (PKR). PACT participates in several cellular pathways, of which its role as a PKR activator protein during integrated stress response (ISR) is the best characterized. Previously, we have established that the DYT-PRKRA mutations cause enhanced activation of PKR during ISR to sensitize DYT-PRKRA cells to apoptosis. In this study, we evaluate if the most prevalent substitution mutation reported in DYT-PRKRA patients alters PACT's functional role in induction of type I IFNs via the retinoic acid-inducible gene I (RIG-I) signaling. Our results indicate that the P222L mutation augments PACT's ability to induce IFN β in response to dsRNA and the basal expression of IFN β and IFN-stimulated genes (ISGs) is higher in DYT-PRKRA patient cells compared to cells from the unaffected controls. Additionally, IFN β and ISGs are also induced at higher levels in DYT-PRKRA cells in response to dsRNA. These results offer a new avenue for investigations directed towards understanding the underlying molecular pathomechanisms in DYT-PRKRA.
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Affiliation(s)
- Lauren S. Vaughn
- Department of Biological Sciences, University of South Carolina, 700 Sumter Street, Columbia, SC 29208, USA; (L.S.V.); (K.F.); (S.B.B.)
| | - Kenneth Frederick
- Department of Biological Sciences, University of South Carolina, 700 Sumter Street, Columbia, SC 29208, USA; (L.S.V.); (K.F.); (S.B.B.)
| | - Samuel B. Burnett
- Department of Biological Sciences, University of South Carolina, 700 Sumter Street, Columbia, SC 29208, USA; (L.S.V.); (K.F.); (S.B.B.)
| | - Nutan Sharma
- Department of Neurology, Massachusetts General Hospital, Charlestown, MA 02129, USA; (N.S.); (D.C.B.)
| | - D. Cristopher Bragg
- Department of Neurology, Massachusetts General Hospital, Charlestown, MA 02129, USA; (N.S.); (D.C.B.)
| | - Sarah Camargos
- Department of Internal Medicine, Federal University of Minas Gerais, Belo Horizonte 31270-901, Brazil; (S.C.); (F.C.)
| | - Francisco Cardoso
- Department of Internal Medicine, Federal University of Minas Gerais, Belo Horizonte 31270-901, Brazil; (S.C.); (F.C.)
| | - Rekha C. Patel
- Department of Biological Sciences, University of South Carolina, 700 Sumter Street, Columbia, SC 29208, USA; (L.S.V.); (K.F.); (S.B.B.)
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Lange LM, Junker J, Loens S, Baumann H, Olschewski L, Schaake S, Madoev H, Petkovic S, Kuhnke N, Kasten M, Westenberger A, Domingo A, Marras C, König IR, Camargos S, Ozelius LJ, Klein C, Lohmann K. Genotype-Phenotype Relations for Isolated Dystonia Genes: MDSGene Systematic Review. Mov Disord 2021; 36:1086-1103. [PMID: 33502045 DOI: 10.1002/mds.28485] [Citation(s) in RCA: 69] [Impact Index Per Article: 23.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2020] [Revised: 11/24/2020] [Accepted: 12/07/2020] [Indexed: 12/14/2022] Open
Abstract
This comprehensive MDSGene review is devoted to 7 genes - TOR1A, THAP1, GNAL, ANO3, PRKRA, KMT2B, and HPCA - mutations in which may cause isolated dystonia. It followed MDSGene's standardized data extraction protocol and screened a total of ~1200 citations. Phenotypic and genotypic data on ~1200 patients with 254 different mutations were curated and analyzed. There were differences regarding age at onset, site of onset, and distribution of symptoms across mutation carriers in all 7 genes. Although carriers of TOR1A, THAP1, PRKRA, KMT2B, or HPCA mutations mostly showed childhood and adolescent onset, patients with GNAL and ANO3 mutations often developed first symptoms in adulthood. GNAL and KMT2B mutation carriers frequently have 1 predominant site of onset, that is, the neck (GNAL) or the lower limbs (KMT2B), whereas site of onset in DYT-TOR1A, DYT-THAP1, DYT-ANO3, DYT-PRKRA, and DYT-HPCA was broader. However, in most DYT-THAP1 and DYT-ANO3 patients, dystonia first manifested in the upper half of the body (upper limb, neck, and craniofacial/laryngeal), whereas onset in DYT-TOR1A, DYT-PRKRA and DYT-HPCA was frequently observed in an extremity, including both upper and lower ones. For ANO3, a segmental/multifocal distribution was typical, whereas TOR1A, PRKRA, KMT2B, and HPCA mutation carriers commonly developed generalized dystonia. THAP1 mutation carriers presented with focal, segmental/multifocal, or generalized dystonia in almost equal proportions. GNAL mutation carriers rarely showed generalization. This review provides a comprehensive overview of the current knowledge of hereditary isolated dystonia. The data are also available in an online database (http://www.mdsgene.org), which additionally offers descriptive summary statistics. © 2021 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.
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Affiliation(s)
- Lara M Lange
- Institute of Neurogenetics, University of Lübeck, Lübeck, Germany
| | - Johanna Junker
- Institute of Neurogenetics, University of Lübeck, Lübeck, Germany
- Department of Neurology, University of Lübeck, Lübeck, Germany
| | - Sebastian Loens
- Institute of Neurogenetics, University of Lübeck, Lübeck, Germany
- Department of Neurology, University of Lübeck, Lübeck, Germany
| | - Hauke Baumann
- Institute of Neurogenetics, University of Lübeck, Lübeck, Germany
| | - Luisa Olschewski
- Institute of Neurogenetics, University of Lübeck, Lübeck, Germany
| | - Susen Schaake
- Institute of Neurogenetics, University of Lübeck, Lübeck, Germany
| | - Harutyun Madoev
- Institute of Neurogenetics, University of Lübeck, Lübeck, Germany
| | - Sonja Petkovic
- Institute of Neurogenetics, University of Lübeck, Lübeck, Germany
| | - Neele Kuhnke
- Institute of Neurogenetics, University of Lübeck, Lübeck, Germany
| | - Meike Kasten
- Institute of Neurogenetics, University of Lübeck, Lübeck, Germany
- Department of Psychiatry and Psychotherapy, University of Lübeck, Lübeck, Germany
| | - Ana Westenberger
- Institute of Neurogenetics, University of Lübeck, Lübeck, Germany
| | - Aloysius Domingo
- Center for Genomic Medicine, Massachusetts General Hospital, Boston, Massachusetts, USA
| | - Connie Marras
- The Morton and Gloria Shulman Movement Disorders Centre and the Edmond J Safra Program in Parkinson's Disease, Toronto Western Hospital, University of Toronto, Toronto, Ontario, Canada
| | - Inke R König
- Institute of Medical Biometry and Statistics, University of Lübeck, Lübeck, Germany
| | - Sarah Camargos
- Movement Disorders Unit, Neurology Service, Internal Medicine Department, Hospital das Clínicas, The Federal University of Minas Gerais, Belo Horizonte, Brazil
| | - Laurie J Ozelius
- Department of Neurology, Harvard Medical School and Massachusetts General Hospital, Charlestown, Massachusetts, USA
| | - Christine Klein
- Institute of Neurogenetics, University of Lübeck, Lübeck, Germany
- Department of Neurology, University of Lübeck, Lübeck, Germany
| | - Katja Lohmann
- Institute of Neurogenetics, University of Lübeck, Lübeck, Germany
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Masnada S, Martinelli D, Correa-Vela M, Agolini E, Baide-Mairena H, Marcé-Grau A, Parazzini C, Veggiotti P, Perez-Duenas B, Tonduti D. PRKRA-Related Disorders: Bilateral Striatal Degeneration in Addition to DYT16 Spectrum. Mov Disord 2021; 36:1038-1040. [PMID: 33606314 DOI: 10.1002/mds.28492] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2020] [Revised: 12/01/2020] [Accepted: 12/21/2020] [Indexed: 12/17/2022] Open
Affiliation(s)
- Silvia Masnada
- Child Neurology Unit, COALA (Center for Diagnosis and Treatment of Leukodystrophies), V. Buzzi Children's Hospital, Milan, Italy
| | - Diego Martinelli
- Division of Metabolism, Bambino Gesù Children's Hospital, IRCCS, Rome, Italy
| | - Marta Correa-Vela
- Paediatric Neurology Research Group, Valld'Hebron Research Institute, Universitat Autònoma de Barcelona, Barcelona, Spain
| | - Emanuele Agolini
- Laboratory of Medical Genetics, Bambino Gesù Children's Hospital, IRCCS, Rome, Italy
| | - Heidy Baide-Mairena
- Paediatric Neurology Research Group, Valld'Hebron Research Institute, Universitat Autònoma de Barcelona, Barcelona, Spain
| | - Anna Marcé-Grau
- Paediatric Neurology Research Group, Valld'Hebron Research Institute, Universitat Autònoma de Barcelona, Barcelona, Spain
| | - Cecilia Parazzini
- Paediatric Radiology and Neuroradiology Department, COALA (Center for Diagnosis and Treatment of Leukodystrophies)-V. Buzzi Children's Hospital, Milan, Italy
| | - Pierangelo Veggiotti
- Child Neurology Unit, COALA (Center for Diagnosis and Treatment of Leukodystrophies), V. Buzzi Children's Hospital, Milan, Italy
- Department of Biomedical and Clinical Sciences, L. Sacco, University of Milan, Milan, Italy
| | - Belen Perez-Duenas
- Department of Child Neurology, Hospital Valld'Hebron-Institut de Recerca (VHIR), Barcelona, Spain
- CIBERER, Centro de Investigaciones Biomédicas en Red de Enfermedades Raras, Madrid, Spain
- Faculty of Medicine, Universitat Autònoma de Barcelona, UnitatDocentValld'Hebrón, Barcelona, Spain
| | - Davide Tonduti
- Child Neurology Unit, COALA (Center for Diagnosis and Treatment of Leukodystrophies), V. Buzzi Children's Hospital, Milan, Italy
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Weissbach A, Saranza G, Domingo A. Combined dystonias: clinical and genetic updates. J Neural Transm (Vienna) 2020; 128:417-429. [PMID: 33099685 DOI: 10.1007/s00702-020-02269-w] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2020] [Accepted: 10/09/2020] [Indexed: 12/28/2022]
Abstract
The genetic combined dystonias are a clinically and genetically heterogeneous group of neurologic disorders defined by the overlap of dystonia and other movement disorders such as parkinsonism or myoclonus. The number of genes associated with combined dystonia syndromes has been increasing due to the wider recognition of clinical features and broader use of genetic testing. Nevertheless, these diseases are still rare and represent only a small subgroup among all dystonias. Dopa-responsive dystonia (DYT/PARK-GCH1), rapid-onset dystonia-parkinsonism (DYT/PARK-ATP1A3), X-linked dystonia-parkinsonism (XDP, DYT/PARK-TAF1), and young-onset dystonia-parkinsonism (DYT/PARK-PRKRA) are monogenic combined dystonias accompanied by parkinsonian features. Meanwhile, MYC/DYT-SGCE and MYC/DYT-KCTD17 are characterized by dystonia in combination with myoclonus. In the past, common molecular pathways between these syndromes were the center of interest. Although the encoded proteins rather affect diverse cellular functions, recent neurophysiological evidence suggests similarities in the underlying mechanism in a subset. This review summarizes recent developments in the combined dystonias, focusing on clinico-genetic features and neurophysiologic findings. Disease-modifying therapies remain unavailable to date; an overview of symptomatic therapies for these disorders is also presented.
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Affiliation(s)
- Anne Weissbach
- Institute of Neurogenetics, University of Lübeck, Lübeck, Germany.,Institute of Systems Motor Science, University of Lübeck, Lübeck, Germany
| | - Gerard Saranza
- Edmond J. Safra Program in Parkinson's Disease and the Morton and Gloria Shulman Movement Disorders Clinic, Toronto Western Hospital, Toronto, ON, Canada
| | - Aloysius Domingo
- Center for Genomic Medicine, Massachusetts General Hospital, Boston, MA, USA. .,Collaborative Center for X-Linked Dystonia-Parkinsonism, Department of Neurology, Massachusetts General Hospital, Boston, MA, USA.
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8
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Dystonia 16 (DYT16) mutations in PACT cause dysregulated PKR activation and eIF2α signaling leading to a compromised stress response. Neurobiol Dis 2020; 146:105135. [PMID: 33049316 DOI: 10.1016/j.nbd.2020.105135] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2020] [Revised: 09/17/2020] [Accepted: 10/07/2020] [Indexed: 12/17/2022] Open
Abstract
Dystonia 16 (DYT16) is caused by mutations in PACT, the protein activator of interferon-induced double-stranded RNA-activated protein kinase (PKR). PKR regulates the integrated stress response (ISR) via phosphorylation of the translation initiation factor eIF2α. This post-translational modification attenuates general protein synthesis while concomitantly triggering enhanced translation of a few specific transcripts leading either to recovery and homeostasis or cellular apoptosis depending on the intensity and duration of stress signals. PKR plays a regulatory role in determining the cellular response to viral infections, oxidative stress, endoplasmic reticulum (ER) stress, and growth factor deprivation. In the absence of stress, both PACT and PKR are bound by their inhibitor transactivation RNA-binding protein (TRBP) thereby keeping PKR inactive. Under conditions of cellular stress these inhibitory interactions dissociate facilitating PACT-PACT interactions critical for PKR activation. While both PACT-TRBP and PKR-TRBP interactions are pro-survival, PACT-PACT and PACT-PKR interactions are pro-apoptotic. In this study we evaluate if five DYT16 substitution mutations alter PKR activation and ISR. Our results indicate that the mutant DYT16 proteins show stronger PACT-PACT interactions and enhanced PKR activation. In DYT16 patient derived lymphoblasts the enhanced PACT-PKR interactions and heightened PKR activation leads to a dysregulation of ISR and increased apoptosis. More importantly, this enhanced sensitivity to ER stress can be rescued by luteolin, which disrupts PACT-PKR interactions. Our results not only demonstrate the impact of DYT16 mutations on regulation of ISR and DYT16 etiology but indicate that therapeutic interventions could be possible after a further evaluation of such strategies.
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Burnett SB, Vaughn LS, Strom JM, Francois A, Patel RC. A truncated PACT protein resulting from a frameshift mutation reported in movement disorder DYT16 triggers caspase activation and apoptosis. J Cell Biochem 2019; 120:19004-19018. [PMID: 31246344 DOI: 10.1002/jcb.29223] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2018] [Accepted: 06/04/2019] [Indexed: 01/21/2023]
Abstract
Protein Activator (PACT) activates the interferon (IFN)-induced double-stranded (ds) RNA-activated protein kinase (PKR) in response to stress signals. Oxidative stress and endoplasmic reticulum (ER) stress causes PACT-mediated PKR activation, which leads to phosphorylation of translation initiation factor eIF2α, inhibition of protein synthesis, and apoptosis. A dominantly inherited form of early-onset dystonia 16 (DYT16) has been identified to arise due to a frameshift (FS) mutation in PACT. To examine the effect of the resulting truncated mutant PACT protein on the PKR pathway, we examined the biochemical properties of the mutant protein and its effect on mammalian cells. Our results indicate that the FS mutant protein loses its ability to bind dsRNA as well as its ability to interact with PKR while surprisingly retaining the ability to interact with PACT and PKR-inhibitory protein TRBP. The truncated FS mutant protein, when expressed as a fusion protein with a N-terminal fluorescent mCherry tag aggregates in mammalian cells to induce apoptosis via activation of caspases both in a PKR- and PACT-dependent as well as independent manner. Our results indicate that interaction of FS mutant protein with PKR inhibitor TRBP can dissociate PACT from the TRBP-PACT complex resulting in PKR activation and consequent apoptosis. These findings are relevant to diseases resulting from protein aggregation especially since the PKR activation is a characteristic of several neurodegenerative conditions.
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Affiliation(s)
- Samuel B Burnett
- Department of Biological Sciences University of South Carolina, University of South Carolina, Columbia, South Carolina
| | - Lauren S Vaughn
- Department of Biological Sciences University of South Carolina, University of South Carolina, Columbia, South Carolina
| | - Joelle M Strom
- Department of Biological Sciences University of South Carolina, University of South Carolina, Columbia, South Carolina
| | - Ashley Francois
- Department of Biological Sciences University of South Carolina, University of South Carolina, Columbia, South Carolina
| | - Rekha C Patel
- Department of Biological Sciences University of South Carolina, University of South Carolina, Columbia, South Carolina
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10
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Dos Santos CO, da Silva-Júnior FP, Puga RD, Barbosa ER, Azevedo Silva SMC, Borges V, Limongi JCP, Rocha MSG, Ferraz HB, de Carvalho Aguiar P. The prevalence of PRKRA mutations in idiopathic dystonia. Parkinsonism Relat Disord 2017; 48:93-96. [PMID: 29279192 DOI: 10.1016/j.parkreldis.2017.12.015] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/23/2017] [Revised: 12/01/2017] [Accepted: 12/12/2017] [Indexed: 12/21/2022]
Abstract
INTRODUCTION DYT-PRKRA (DYT16) is considered a rare cause of dystonia-parkinsonism. The significance of this gene as a cause of dystonia and its phenotypical characterization must be determined in larger cohorts. We aimed to investigate the role of PRKRA in patients with dystonia. METHODS We sequenced PRKRA in 153 unrelated Brazilian patients with idiopathic dystonia. The frequency of novel missense variants was investigated in healthy Brazilian controls and in public databases. Homozygosity in the PRKRA region was assessed through polymorphic markers. RESULTS PRKRA variants were identified in seven probands with isolated dystonia, including a novel c.C795A variant in compound heterozygosity with the previously described c.C665T variant. Heterozygosity in the gene region was observed in two probands who were homozygous for c.C665T, indicating that this mutation originated from independent events, suggesting a hotspot. CONCLUSION PRKRA is not an unusual cause of idiopathic dystonia. In this cohort, it was responsible for 4.5% of the total of cases (4.9% of the isolated dystonia cases). The most common phenotype was early-onset isolated focal dystonia followed by generalization, parkinsonism was not observed. This is first report of PRKRA causing adulthood-onset dystonia. Screenings of large cohorts are recommended to investigate the role of this gene in isolated dystonia, as well as in dystonia-parkinsonism cases worldwide.
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Affiliation(s)
| | | | | | - Egberto Reis Barbosa
- Department of Neurology, Faculdade de Medicina da Universidade de Sao Paulo, Sao Paulo, SP, Brazil
| | - Sonia Maria Cesar Azevedo Silva
- Hospital do Servidor Público Estadual, Sao Paulo, SP, Brazil; Department of Neurology and Neurosurgery, Universidade Federal de Sao Paulo, Sao Paulo, SP, Brazil
| | - Vanderci Borges
- Department of Neurology and Neurosurgery, Universidade Federal de Sao Paulo, Sao Paulo, SP, Brazil
| | | | | | - Henrique Ballalai Ferraz
- Department of Neurology and Neurosurgery, Universidade Federal de Sao Paulo, Sao Paulo, SP, Brazil
| | - Patricia de Carvalho Aguiar
- Hospital Israelita Albert Einstein, Sao Paulo, SP, Brazil; Department of Neurology and Neurosurgery, Universidade Federal de Sao Paulo, Sao Paulo, SP, Brazil.
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11
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Quadri M, Olgiati S, Sensi M, Gualandi F, Groppo E, Rispoli V, Graafland J, Breedveld GJ, Fabbrini G, Berardelli A, Bonifati V. PRKRA Mutation Causing Early-Onset Generalized Dystonia-Parkinsonism (DYT16) in an Italian Family. Mov Disord 2016; 31:765-7. [PMID: 26990861 DOI: 10.1002/mds.26583] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2015] [Revised: 01/20/2016] [Accepted: 01/22/2016] [Indexed: 01/08/2023] Open
Affiliation(s)
- Marialuisa Quadri
- Department of Clinical Genetics, Erasmus MC, Rotterdam, The Netherlands
| | - Simone Olgiati
- Department of Clinical Genetics, Erasmus MC, Rotterdam, The Netherlands
| | - Mariachiara Sensi
- Department of Neurology and Rehabilitation, University Hospital Arcispedale S. Anna, Ferrara, Italy
| | - Francesca Gualandi
- Department of Reproduction and Growth, UOL of Medical Genetics, University Hospital S. Anna, Ferrara, Italy
| | - Elisabetta Groppo
- Department of Biomedical and Specialistic Surgical Sciences, University Hospital Arcispedale S. Anna, Ferrara, Italy
| | - Vittorio Rispoli
- Department of Biomedical and Specialistic Surgical Sciences, University Hospital Arcispedale S. Anna, Ferrara, Italy
| | - Josja Graafland
- Department of Clinical Genetics, Erasmus MC, Rotterdam, The Netherlands
| | - Guido J Breedveld
- Department of Clinical Genetics, Erasmus MC, Rotterdam, The Netherlands
| | - Giovanni Fabbrini
- Department of Neurology and Psychiatry, Sapienza University of Rome and, IRCSS Neuromed, Pozzilli, Italy
| | - Alfredo Berardelli
- Department of Neurology and Psychiatry, Sapienza University of Rome and, IRCSS Neuromed, Pozzilli, Italy
| | - Vincenzo Bonifati
- Department of Clinical Genetics, Erasmus MC, Rotterdam, The Netherlands
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12
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Dickerman BK, White CL, Kessler PM, Sadler AJ, Williams BRG, Sen GC. The protein activator of protein kinase R, PACT/RAX, negatively regulates protein kinase R during mouse anterior pituitary development. FEBS J 2015; 282:4766-81. [PMID: 26414443 DOI: 10.1111/febs.13533] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2015] [Revised: 09/23/2015] [Accepted: 09/24/2015] [Indexed: 11/27/2022]
Abstract
The murine double-stranded RNA-binding protein termed protein kinase R (PKR)-associated protein X (RAX) and the human homolog, protein activator of PKR (PACT), were originally characterized as activators of PKR. Mice deficient in RAX show reproductive and developmental defects, including reduced body size, craniofacial defects and anterior pituitary hypoplasia. As these defects are not observed in PKR-deficient mice, the phenotype has been attributed to PKR-independent activities of RAX. Here we further investigated the involvement of PKR in the physiological function of RAX, by generating rax(-/-) mice deficient in PKR, or carrying a kinase-inactive mutant of PKR (K271R) or an unphosphorylatable mutant of the PKR substrate eukaryotic translation initiation factor 2 α subunit (eIF2α) (S51A). Ablating PKR expression rescued the developmental and reproductive deficiencies in rax(-/-) mice. Generating rax(-/-) mice with a kinase-inactive mutant of PKR resulted in similar rescue, confirming that the rax(-/-) defects are PKR dependent; specifically that the kinase activity of PKR was required for these defects. Moreover, generating rax(-/-) mice that were heterozygous for an unphosphorylatable mutant eIF2α provides partial rescue of the rax(-/-) defect, consistent with mutation of one copy of the Eif2s1 gene. These observations were further investigated in vitro by reducing RAX expression in anterior pituitary cells, resulting in increased PKR activity and induction of the PKR-regulated cyclin-dependent kinase inhibitor p21(WAF1/CIP1). These results demonstrate that PKR kinase activity is required for onset of the rax(-/-) phenotype, implying an unexpected function for RAX as a negative regulator of PKR in the context of postnatal anterior pituitary tissue, and identify a critical role for the regulation of PKR activity for normal development.
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Affiliation(s)
- Benjamin K Dickerman
- Department of Molecular Genetics, Lerner Research Institute, Cleveland Clinic, OH, USA.,Graduate Program in Molecular Virology, Case Western Reserve University, Cleveland, OH, USA
| | - Christine L White
- Department of Molecular Genetics, Lerner Research Institute, Cleveland Clinic, OH, USA
| | - Patricia M Kessler
- Department of Molecular Genetics, Lerner Research Institute, Cleveland Clinic, OH, USA
| | - Anthony J Sadler
- Centre for Cancer Research, Hudson Institute of Medical Research, Clayton, Victoria, Australia.,Department of Molecular and Translational Science, Monash University, Clayton, Victoria, Australia
| | - Bryan R G Williams
- Centre for Cancer Research, Hudson Institute of Medical Research, Clayton, Victoria, Australia.,Department of Molecular and Translational Science, Monash University, Clayton, Victoria, Australia
| | - Ganes C Sen
- Department of Molecular Genetics, Lerner Research Institute, Cleveland Clinic, OH, USA.,Graduate Program in Molecular Virology, Case Western Reserve University, Cleveland, OH, USA
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Vaughn LS, Bragg DC, Sharma N, Camargos S, Cardoso F, Patel RC. Altered activation of protein kinase PKR and enhanced apoptosis in dystonia cells carrying a mutation in PKR activator protein PACT. J Biol Chem 2015; 290:22543-57. [PMID: 26231208 DOI: 10.1074/jbc.m115.669408] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2015] [Indexed: 12/21/2022] Open
Abstract
PACT is a stress-modulated activator of the interferon-induced double-stranded RNA-activated protein kinase (PKR). Stress-induced phosphorylation of PACT is essential for PACT's association with PKR leading to PKR activation. PKR activation leads to phosphorylation of translation initiation factor eIF2α inhibition of protein synthesis and apoptosis. A recessively inherited form of early-onset dystonia DYT16 has been recently identified to arise due to a homozygous missense mutation P222L in PACT. To examine if the mutant P222L protein alters the stress-response pathway, we examined the ability of mutant P222L to interact with and activate PKR. Our results indicate that the substitution mutant P222L activates PKR more robustly and for longer duration albeit with slower kinetics in response to the endoplasmic reticulum stress. In addition, the affinity of PACT-PACT and PACT-PKR interactions is enhanced in dystonia patient lymphoblasts, thereby leading to intensified PKR activation and enhanced cellular death. P222L mutation also changes the affinity of PACT-TRBP interaction after cellular stress, thereby offering a mechanism for the delayed PKR activation in response to stress. Our results demonstrate the impact of a dystonia-causing substitution mutation on stress-induced cellular apoptosis.
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Affiliation(s)
- Lauren S Vaughn
- From the University of South Carolina, Department of Biological Sciences, Columbia, South Carolina 29208
| | - D Cristopher Bragg
- Massachusetts General Hospital, Department of Neurology, Charlestown, Massachusetts 02129, and
| | - Nutan Sharma
- Massachusetts General Hospital, Department of Neurology, Charlestown, Massachusetts 02129, and
| | - Sarah Camargos
- Federal University of Minas Gerais, Department of Internal Medicine, 31270-901 Belo Horizonte, MG, Brazil
| | - Francisco Cardoso
- Federal University of Minas Gerais, Department of Internal Medicine, 31270-901 Belo Horizonte, MG, Brazil
| | - Rekha C Patel
- From the University of South Carolina, Department of Biological Sciences, Columbia, South Carolina 29208,
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