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Pakdaman Y, Sanchez-Guixé M, Kleppe R, Erdal S, Bustad HJ, Bjørkhaug L, Haugarvoll K, Tzoulis C, Heimdal K, Knappskog PM, Johansson S, Aukrust I. In vitro characterization of six STUB1 variants in spinocerebellar ataxia 16 reveals altered structural properties for the encoded CHIP proteins. Biosci Rep 2017; 37:BSR20170251. [PMID: 28396517 PMCID: PMC5408658 DOI: 10.1042/bsr20170251] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2017] [Revised: 04/07/2017] [Accepted: 04/10/2017] [Indexed: 11/24/2022] Open
Abstract
Spinocerebellar ataxia, autosomal recessive 16 (SCAR16) is caused by biallelic mutations in the STIP1 homology and U-box containing protein 1 (STUB1) gene encoding the ubiquitin E3 ligase and dimeric co-chaperone C-terminus of Hsc70-interacting protein (CHIP). It has been proposed that the disease mechanism is related to CHIP's impaired E3 ubiquitin ligase properties and/or interaction with its chaperones. However, there is limited knowledge on how these mutations affect the stability, folding, and protein structure of CHIP itself. To gain further insight, six previously reported pathogenic STUB1 variants (E28K, N65S, K145Q, M211I, S236T, and T246M) were expressed as recombinant proteins and studied using limited proteolysis, size-exclusion chromatography (SEC), and circular dichroism (CD). Our results reveal that N65S shows increased CHIP dimerization, higher levels of α-helical content, and decreased degradation rate compared with wild-type (WT) CHIP. By contrast, T246M demonstrates a strong tendency for aggregation, a more flexible protein structure, decreased levels of α-helical structures, and increased degradation rate compared with WT CHIP. E28K, K145Q, M211I, and S236T also show defects on structural properties compared with WT CHIP, although less profound than what observed for N65S and T246M. In conclusion, our results illustrate that some STUB1 mutations known to cause recessive SCAR16 have a profound impact on the protein structure, stability, and ability of CHIP to dimerize in vitro. These results add to the growing understanding on the mechanisms behind the disorder.
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Affiliation(s)
- Yasaman Pakdaman
- Center for Medical Genetics and Molecular Medicine, Haukeland University Hospital, Bergen, Norway
- Department of Clinical Science, University of Bergen, Bergen, Norway
| | - Monica Sanchez-Guixé
- Center for Medical Genetics and Molecular Medicine, Haukeland University Hospital, Bergen, Norway
| | - Rune Kleppe
- K.G. Jebsen Centre for Neuropsychiatric Disorders, Department of Biomedicine, University of Bergen, Bergen, Norway
| | - Sigrid Erdal
- Center for Medical Genetics and Molecular Medicine, Haukeland University Hospital, Bergen, Norway
| | - Helene J Bustad
- Department of Biomedicine, University of Bergen, Bergen, Norway
| | - Lise Bjørkhaug
- Department of Biomedical Laboratory Sciences and Chemical Engineering, Western Norway University of Applied Sciences, Bergen, Norway
| | - Kristoffer Haugarvoll
- Department of Neurology, Haukeland University Hospital, Bergen, Norway
- Department of Clinical Medicine, University of Bergen, Bergen, Norway
| | - Charalampos Tzoulis
- Department of Neurology, Haukeland University Hospital, Bergen, Norway
- Department of Clinical Medicine, University of Bergen, Bergen, Norway
| | - Ketil Heimdal
- Department of Medical Genetics, Oslo University Hospital, Oslo, Norway
| | - Per M Knappskog
- Center for Medical Genetics and Molecular Medicine, Haukeland University Hospital, Bergen, Norway
- K.G. Jebsen Centre for Neuropsychiatric Disorders, Department of Clinical Science, University of Bergen, Bergen, Norway
| | - Stefan Johansson
- Center for Medical Genetics and Molecular Medicine, Haukeland University Hospital, Bergen, Norway
- K.G. Jebsen Centre for Neuropsychiatric Disorders, Department of Clinical Science, University of Bergen, Bergen, Norway
| | - Ingvild Aukrust
- Center for Medical Genetics and Molecular Medicine, Haukeland University Hospital, Bergen, Norway
- Department of Clinical Science, University of Bergen, Bergen, Norway
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Nath SR, Lieberman AP. The Ubiquitination, Disaggregation and Proteasomal Degradation Machineries in Polyglutamine Disease. Front Mol Neurosci 2017; 10:78. [PMID: 28381987 PMCID: PMC5360718 DOI: 10.3389/fnmol.2017.00078] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2017] [Accepted: 03/06/2017] [Indexed: 12/14/2022] Open
Abstract
Polyglutamine disorders are chronic, progressive neurodegenerative diseases caused by expansion of a glutamine tract in widely expressed genes. Despite excellent models of disease, a well-documented clinical history and progression, and established genetic causes, there are no FDA approved, disease modifying treatments for these disorders. Downstream of the mutant protein, several divergent pathways of toxicity have been identified over the last several decades, supporting the idea that targeting only one of these pathways of toxicity is unlikely to robustly alleviate disease progression. As a result, a vast body of research has focused on eliminating the mutant protein to broadly prevent downstream toxicity, either by silencing mutant protein expression or leveraging the endogenous protein quality control machinery. In the latter approach, a focus has been placed on four critical components of mutant protein degradation that are active in the nucleus, a key site of toxicity: disaggregation, ubiquitination, deubiquitination, and proteasomal activity. These machineries have unique functional components, but work together as a cellular defense system that can be successfully leveraged to alleviate disease phenotypes in several models of polyglutamine toxicity. This review will highlight recent advances in understanding both the potential and role of these components of the protein quality control machinery in polyglutamine disease pathophysiology.
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Affiliation(s)
- Samir R Nath
- Medical Scientist Training Program, University of Michigan Medical SchoolAnn Arbor, MI, USA; Cellular and Molecular Biology Graduate Program, University of Michigan Medical SchoolAnn Arbor, MI, USA; Department of Pathology, University of Michigan Medical SchoolAnn Arbor, MI, USA
| | - Andrew P Lieberman
- Department of Pathology, University of Michigan Medical School Ann Arbor, MI, USA
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53
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Synofzik M, Schüle R. Overcoming the divide between ataxias and spastic paraplegias: Shared phenotypes, genes, and pathways. Mov Disord 2017; 32:332-345. [PMID: 28195350 PMCID: PMC6287914 DOI: 10.1002/mds.26944] [Citation(s) in RCA: 124] [Impact Index Per Article: 17.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2016] [Revised: 01/07/2017] [Accepted: 01/15/2017] [Indexed: 12/11/2022] Open
Abstract
Autosomal-dominant spinocerebellar ataxias, autosomal-recessive spinocerebellar ataxias, and hereditary spastic paraplegias have traditionally been designated in separate clinicogenetic disease classifications. This classification system still largely frames clinical thinking and genetic workup in clinical practice. Yet, with the advent of next-generation sequencing, phenotypically unbiased studies have revealed the limitations of this classification system. Various genes (eg, SPG7, SYNE1, PNPLA6) traditionally rooted in either the ataxia or hereditary spastic paraplegia classification system have now been shown to cause ataxia on the one end of the disease continuum and hereditary spastic paraplegia on the other. Other genes such as GBA2 and KIF1C were almost simultaneously published as both a hereditary spastic paraplegia and an ataxia gene. The variability and fluidity of observed phenotypes along the ataxia-spasticity spectrum warrants a rethinking of the traditional classification system. We propose to replace this divisive diagnosis-driven ataxia and hereditary spastic paraplegia classification system by a descriptive, unbiased approach of modular phenotyping. This approach is also open to expansion of the phenotype beyond ataxia and spasticity, which often occur as part of broader multisystem neuronal dysfunction. The concept of a continuous ataxia-spasticity disease spectrum is further supported by ataxias and hereditary spastic paraplegias sharing not only overlapping phenotypes and underlying genes, but also common cellular pathways and disease mechanisms. This suggests a shared vulnerability of cerebellar and corticospinal neurons for common pathophysiological processes. It might be this mechanistic overlap that drives their clinical overlap. A mechanistically inspired classification system will help to pave the way for mechanism-based strategies for drug development. © 2017 International Parkinson and Movement Disorder Society.
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Affiliation(s)
- Matthis Synofzik
- Department of Neurodegeneration, Hertie Institute for Clinical Brain Research (HIH), University of Tübingen, Tübingen, Germany
- German Center for Neurodegenerative Diseases (DZNE), Tübingen, Germany
| | - Rebecca Schüle
- Department of Neurodegeneration, Hertie Institute for Clinical Brain Research (HIH), University of Tübingen, Tübingen, Germany
- German Center for Neurodegenerative Diseases (DZNE), Tübingen, Germany
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54
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Picker-Minh S, Hartenstein S, Proquitté H, Fröhler S, Raile V, Kraemer N, Apeshiotis S, Leipoldt M, Kalache KD, Morris-Rosendahl D, Boltshauser E, Chen W, Kaindl AM. Pontine Tegmental Cap Dysplasia in an Extremely Preterm Infant and Review of the Literature. J Child Neurol 2017; 32:334-340. [PMID: 28193110 DOI: 10.1177/0883073816680748] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Pontine tegmental cap dysplasia is a rare hindbrain malformation syndrome with a hypoplastic pons, a tissue protrusion into the fourth ventricle, and cranial nerve dysfunction. We here report clinical, imaging, and genetic findings of the first extremely low-birth-weight preterm infant with pontine tegmental cap dysplasia born at 25 weeks of gestation and provide an overview of 29 sporadic cases. A prenatally diagnosed hypoplastic and rostrally shifted cerebellum was indicative of a hindbrain defect and later identified as an early sign of pontine tegmental cap dysplasia in our patient. The neonate exhibited severe muscle hypotonia, persistent thermolability, and clinical signs of an involvement of facial, cochlear, and hypoglossal nerves. Furthermore, paroxysmal episodes of agonizing pain with facial tics, tonic and clonic muscle contractions, blepharospasm, and singultus are highlighted as new phenotypic features of pontine tegmental cap dysplasia. With our report, we present a severe case of pontine tegmental cap dysplasia and provide a brief overview of current knowledge on this rare disease.
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Affiliation(s)
- Sylvie Picker-Minh
- 1 Department of Pediatric Neurology, Charité-Universitätsmedizin Berlin, Berlin, Germany.,2 Institute of Cell Biology and Neurobiology, Charité-Universitätsmedizin Berlin, Berlin, Germany.,3 Sozialpädiatrisches Zentrum (SPZ), Center for Chronic Sick Children, Charité-Universitätsmedizin Berlin, Berlin, Germany.,4 Berlin Institute of Health (BIH), Berlin, Germany
| | | | - Hans Proquitté
- 5 Department of Neonatology, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Sebastian Fröhler
- 6 Berlin Institute for Medical Systems Biology, Max-Delbrück-Center for Molecular Medicine, Berlin, Germany
| | - Vera Raile
- 3 Sozialpädiatrisches Zentrum (SPZ), Center for Chronic Sick Children, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Nadine Kraemer
- 1 Department of Pediatric Neurology, Charité-Universitätsmedizin Berlin, Berlin, Germany.,2 Institute of Cell Biology and Neurobiology, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Sarah Apeshiotis
- 7 Institute of Human Genetics, Albert-Ludwigs University of Freiburg Medical Center, Freiburg, Germany
| | - Michael Leipoldt
- 7 Institute of Human Genetics, Albert-Ludwigs University of Freiburg Medical Center, Freiburg, Germany
| | - Karim D Kalache
- 8 Department of Gynecology and Perinatal Medicine, Charité-Universitätsmedizin Berlin, Germany
| | - Deborah Morris-Rosendahl
- 7 Institute of Human Genetics, Albert-Ludwigs University of Freiburg Medical Center, Freiburg, Germany.,9 Clinical Genetics and Genomics, Royal Brompton and Harefield NHS Foundation Trust, Royal Brompton Hospital, London, United Kingdom
| | - Eugen Boltshauser
- 10 Department of Pediatric Neurology, University Children's Hospital of Zürich, Zürich, Switzerland
| | - Wei Chen
- 6 Berlin Institute for Medical Systems Biology, Max-Delbrück-Center for Molecular Medicine, Berlin, Germany
| | - Angela M Kaindl
- 2 Institute of Cell Biology and Neurobiology, Charité-Universitätsmedizin Berlin, Berlin, Germany.,3 Sozialpädiatrisches Zentrum (SPZ), Center for Chronic Sick Children, Charité-Universitätsmedizin Berlin, Berlin, Germany.,4 Berlin Institute of Health (BIH), Berlin, Germany
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Beaudin M, Klein CJ, Rouleau GA, Dupré N. Systematic review of autosomal recessive ataxias and proposal for a classification. CEREBELLUM & ATAXIAS 2017; 4:3. [PMID: 28250961 PMCID: PMC5324265 DOI: 10.1186/s40673-017-0061-y] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/22/2016] [Accepted: 02/17/2017] [Indexed: 01/26/2023]
Abstract
Background The classification of autosomal recessive ataxias represents a significant challenge because of high genetic heterogeneity and complex phenotypes. We conducted a comprehensive systematic review of the literature to examine all recessive ataxias in order to propose a new classification and properly circumscribe this field as new technologies are emerging for comprehensive targeted gene testing. Methods We searched Pubmed and Embase to identify original articles on recessive forms of ataxia in humans for which a causative gene had been identified. Reference lists and public databases, including OMIM and GeneReviews, were also reviewed. We evaluated the clinical descriptions to determine if ataxia was a core feature of the phenotype and assessed the available evidence on the genotype-phenotype association. Included disorders were classified as primary recessive ataxias, as other complex movement or multisystem disorders with prominent ataxia, or as disorders that may occasionally present with ataxia. Results After removal of duplicates, 2354 references were reviewed and assessed for inclusion. A total of 130 articles were completely reviewed and included in this qualitative analysis. The proposed new list of autosomal recessive ataxias includes 45 gene-defined disorders for which ataxia is a core presenting feature. We propose a clinical algorithm based on the associated symptoms. Conclusion We present a new classification for autosomal recessive ataxias that brings awareness to their complex phenotypes while providing a unified categorization of this group of disorders. This review should assist in the development of a consensus nomenclature useful in both clinical and research applications. Electronic supplementary material The online version of this article (doi:10.1186/s40673-017-0061-y) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Marie Beaudin
- Faculty of Medicine, Université Laval, Quebec city, QC G1V 0A6 Canada
| | | | - Guy A Rouleau
- Department of Neurology and Neurosurgery, McGill University, Montreal, QC H3A 1A4 Canada
| | - Nicolas Dupré
- Faculty of Medicine, Université Laval, Quebec city, QC G1V 0A6 Canada.,Department of Neurological Sciences, CHU de Quebec - Université Laval, 1401 18th street, Québec City, QC G1J 1Z4 Canada
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Hayer SN, Deconinck T, Bender B, Smets K, Züchner S, Reich S, Schöls L, Schüle R, De Jonghe P, Baets J, Synofzik M. STUB1/CHIP mutations cause Gordon Holmes syndrome as part of a widespread multisystemic neurodegeneration: evidence from four novel mutations. Orphanet J Rare Dis 2017; 12:31. [PMID: 28193273 PMCID: PMC5307643 DOI: 10.1186/s13023-017-0580-x] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2016] [Accepted: 01/26/2017] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND CHIP, the protein encoded by STUB1, is a central component of cellular protein homeostasis and interacts with several key proteins involved in the pathogenesis of manifold neurodegenerative diseases. This gives rise to the hypothesis that mutations in STUB1 might cause a far more multisystemic neurodegenerative phenotype than the previously reported cerebellar ataxia syndrome. METHODS Whole exome sequencing data-sets from n = 87 index subjects of two ataxia cohorts were screened for individuals with STUB1 mutations. In-depth phenotyping by clinical evaluation and neuroimaging was performed in mutation carriers. RESULTS We identified four novel STUB1 mutations in three affected subjects from two index families (frequency 2/87 = 2.3%). All three subjects presented with a severe multisystemic phenotype including severe dementia, spastic tetraparesis, epilepsy, and autonomic dysfunction in addition to cerebellar ataxia, plus hypogonadism in one index patient. Diffusion tensor imaging revealed degeneration of manifold supra- and infratentorial tracts. CONCLUSIONS Our findings provide clinical and imaging support for the notion that CHIP is a crucial converging point of manifold neurodegenerative processes, corresponding with its universal biological function in neurodegeneration. Further, our data reveal the second STUB1 family with ataxia plus hypogonadism reported so far, demonstrating that Gordon Holmes syndrome is indeed a recurrent manifestation of STUB1. However, it does not present in isolation, but as part of a broad multisystemic neurodegenerative process. This supports the notion that STUB1 disease should be conceptualized not by historical or clinical syndromic names, but as a variable multisystemic disease defined by disturbed function of the underlying STUB1 gene, which translates into a multidimensional gradual spectrum of variably associated clinical signs and symptoms.
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Affiliation(s)
- Stefanie Nicole Hayer
- Department of Neurodegenerative Diseases, Hertie-Institute for Clinical Brain Research & Center of Neurology, University of Tuebingen, Hoppe-Seyler-Str. 3, 72076 Tuebingen, Germany
- German Center for Neurodegenerative Diseases (DZNE), University of Tuebingen, Tuebingen, Germany
| | - Tine Deconinck
- Neurogenetics Group, Department of Molecular Genetics, VIB, Antwerp, Belgium
- Laboratories of Neurogenetics and Ultrastructural Neuropathology, Institute Born-Bunge, University of Antwerp, Antwerp, Belgium
| | - Benjamin Bender
- Department of Diagnostic and Interventional Neuroradiology, University Hospital Tuebingen, Tuebingen, Germany
| | - Katrien Smets
- Neurogenetics Group, Department of Molecular Genetics, VIB, Antwerp, Belgium
- Laboratories of Neurogenetics and Ultrastructural Neuropathology, Institute Born-Bunge, University of Antwerp, Antwerp, Belgium
- Department of Neurology, Antwerp University Hospital, Antwerp, Belgium
| | - Stephan Züchner
- Dr. John T. Macdonald Foundation, Department of Human Genetics, Miami, USA
- John P. Hussman Institute for Human Genomics, University of Miami, Miller School of Medicine, Miami, USA
| | - Selina Reich
- Department of Neurodegenerative Diseases, Hertie-Institute for Clinical Brain Research & Center of Neurology, University of Tuebingen, Hoppe-Seyler-Str. 3, 72076 Tuebingen, Germany
- German Center for Neurodegenerative Diseases (DZNE), University of Tuebingen, Tuebingen, Germany
| | - Ludger Schöls
- Department of Neurodegenerative Diseases, Hertie-Institute for Clinical Brain Research & Center of Neurology, University of Tuebingen, Hoppe-Seyler-Str. 3, 72076 Tuebingen, Germany
- German Center for Neurodegenerative Diseases (DZNE), University of Tuebingen, Tuebingen, Germany
| | - Rebecca Schüle
- Department of Neurodegenerative Diseases, Hertie-Institute for Clinical Brain Research & Center of Neurology, University of Tuebingen, Hoppe-Seyler-Str. 3, 72076 Tuebingen, Germany
- German Center for Neurodegenerative Diseases (DZNE), University of Tuebingen, Tuebingen, Germany
| | - Peter De Jonghe
- Neurogenetics Group, Department of Molecular Genetics, VIB, Antwerp, Belgium
- Laboratories of Neurogenetics and Ultrastructural Neuropathology, Institute Born-Bunge, University of Antwerp, Antwerp, Belgium
- Department of Neurology, Antwerp University Hospital, Antwerp, Belgium
| | - Jonathan Baets
- Neurogenetics Group, Department of Molecular Genetics, VIB, Antwerp, Belgium
- Laboratories of Neurogenetics and Ultrastructural Neuropathology, Institute Born-Bunge, University of Antwerp, Antwerp, Belgium
- Department of Neurology, Antwerp University Hospital, Antwerp, Belgium
| | - Matthis Synofzik
- Department of Neurodegenerative Diseases, Hertie-Institute for Clinical Brain Research & Center of Neurology, University of Tuebingen, Hoppe-Seyler-Str. 3, 72076 Tuebingen, Germany
- German Center for Neurodegenerative Diseases (DZNE), University of Tuebingen, Tuebingen, Germany
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57
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Joshi V, Amanullah A, Upadhyay A, Mishra R, Kumar A, Mishra A. A Decade of Boon or Burden: What Has the CHIP Ever Done for Cellular Protein Quality Control Mechanism Implicated in Neurodegeneration and Aging? Front Mol Neurosci 2016; 9:93. [PMID: 27757073 PMCID: PMC5047891 DOI: 10.3389/fnmol.2016.00093] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2016] [Accepted: 09/20/2016] [Indexed: 01/13/2023] Open
Abstract
Cells regularly synthesize new proteins to replace old and abnormal proteins for normal cellular functions. Two significant protein quality control pathways inside the cellular milieu are ubiquitin proteasome system (UPS) and autophagy. Autophagy is known for bulk clearance of cytoplasmic aggregated proteins, whereas the specificity of protein degradation by UPS comes from E3 ubiquitin ligases. Few E3 ubiquitin ligases, like C-terminus of Hsc70-interacting protein (CHIP) not only take part in protein quality control pathways, but also plays a key regulatory role in other cellular processes like signaling, development, DNA damage repair, immunity and aging. CHIP targets misfolded proteins for their degradation through proteasome, as well as autophagy; simultaneously, with the help of chaperones, it also regulates folding attempts for misfolded proteins. The broad range of CHIP substrates and their associations with multiple pathologies make it a key molecule to work upon and focus for future therapeutic interventions. E3 ubiquitin ligase CHIP interacts and degrades many protein inclusions formed in neurodegenerative diseases. The presence of CHIP at various nodes of cellular protein-protein interaction network presents this molecule as a potential candidate for further research. In this review, we have explored a wide range of functionality of CHIP inside cells by a detailed presentation of its co-chaperone, E3 and E4 enzyme like functions, with central focus on its protein quality control roles in neurodegenerative diseases. We have also raised many unexplored but expected fundamental questions regarding CHIP functions, which generate hopes for its future applications in research, as well as drug discovery.
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Affiliation(s)
- Vibhuti Joshi
- Cellular and Molecular Neurobiology Unit, Indian Institute of Technology Jodhpur Rajasthan, India
| | - Ayeman Amanullah
- Cellular and Molecular Neurobiology Unit, Indian Institute of Technology Jodhpur Rajasthan, India
| | - Arun Upadhyay
- Cellular and Molecular Neurobiology Unit, Indian Institute of Technology Jodhpur Rajasthan, India
| | - Ribhav Mishra
- Cellular and Molecular Neurobiology Unit, Indian Institute of Technology Jodhpur Rajasthan, India
| | - Amit Kumar
- Centre for Biosciences and Biomedical Engineering, Indian Institute of Technology Indore Madhya Pradesh, India
| | - Amit Mishra
- Cellular and Molecular Neurobiology Unit, Indian Institute of Technology Jodhpur Rajasthan, India
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Del Prete D, Rice RC, Rajadhyaksha AM, D'Adamio L. Amyloid Precursor Protein (APP) May Act as a Substrate and a Recognition Unit for CRL4CRBN and Stub1 E3 Ligases Facilitating Ubiquitination of Proteins Involved in Presynaptic Functions and Neurodegeneration. J Biol Chem 2016; 291:17209-27. [PMID: 27325702 DOI: 10.1074/jbc.m116.733626] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2016] [Indexed: 12/23/2022] Open
Abstract
The amyloid precursor protein (APP), whose mutations cause Alzheimer disease, plays an important in vivo role and facilitates transmitter release. Because the APP cytosolic region (ACR) is essential for these functions, we have characterized its brain interactome. We found that the ACR interacts with proteins that regulate the ubiquitin-proteasome system, predominantly with the E3 ubiquitin-protein ligases Stub1, which binds the NH2 terminus of the ACR, and CRL4(CRBN), which is formed by Cul4a/b, Ddb1, and Crbn, and interacts with the COOH terminus of the ACR via Crbn. APP shares essential functions with APP-like protein-2 (APLP2) but not APP-like protein-1 (APLP1). Noteworthy, APLP2, but not APLP1, interacts with Stub1 and CRL4(CRBN), pointing to a functional pathway shared only by APP and APLP2. In vitro ubiquitination/ubiquitome analysis indicates that these E3 ligases are enzymatically active and ubiquitinate the ACR residues Lys(649/650/651/676/688) Deletion of Crbn reduces ubiquitination of Lys(676) suggesting that Lys(676) is physiologically ubiquitinated by CRL4(CRBN) The ACR facilitated in vitro ubiquitination of presynaptic proteins that regulate exocytosis, suggesting a mechanism by which APP tunes transmitter release. Other dementia-related proteins, namely Tau and apoE, interact with and are ubiquitinated via the ACR in vitro This, and the evidence that CRBN and CUL4B are linked to intellectual disability, prompts us to hypothesize a pathogenic mechanism, in which APP acts as a modulator of E3 ubiquitin-protein ligase(s), shared by distinct neuronal disorders. The well described accumulation of ubiquitinated protein inclusions in neurodegenerative diseases and the link between the ubiquitin-proteasome system and neurodegeneration make this concept plausible.
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Affiliation(s)
- Dolores Del Prete
- From the Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, New York 10461 and
| | - Richard C Rice
- the Division of Pediatric Neurology, Department of Pediatrics, and
| | - Anjali M Rajadhyaksha
- the Division of Pediatric Neurology, Department of Pediatrics, and Feil Family Brain and Mind Research Institute, Weill Cornell Autism Research Program, Weill Cornell Medical College, New York, New York 10065
| | - Luciano D'Adamio
- From the Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, New York 10461 and
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59
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Kawarai T, Tajima A, Kuroda Y, Saji N, Orlacchio A, Terasawa H, Shimizu H, Kita Y, Izumi Y, Mitsui T, Imoto I, Kaji R. A homozygous mutation of VWA3B causes cerebellar ataxia with intellectual disability. J Neurol Neurosurg Psychiatry 2016; 87:656-62. [PMID: 26157035 DOI: 10.1136/jnnp-2014-309828] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/30/2014] [Accepted: 06/15/2015] [Indexed: 12/17/2022]
Abstract
BACKGROUND Hereditary cerebellar ataxia constitutes a heterogeneous group of neurodegenerative disorders, occasionally accompanied by other neurological features. Genetic defects remain to be elucidated in approximately 40% of hereditary cerebellar ataxia cases in Japan. We attempted to identify the gene responsible for autosomal recessive cerebellar ataxia with intellectual disability. METHODS The present study involved three patients in a consanguineous Japanese family. Neurological examination and gene analyses were performed in all family members. We performed genome-wide linkage analysis including single nucleotide polymorphism arrays, copy-number variation analysis and whole exome sequencing. To clarify the functional alteration resulting from the identified mutation, we performed cell viability assay of cultured cells expressing mutant protein. RESULTS One homozygous region shared among the three patients on chromosomes 2p16.1-2q12.3 was identified. Using whole exome sequencing, six homozygous variants in genes in the region were detected. Only one variant, VWA3B c.A1865C, results in a change of a highly conserved amino acid (p.K622T) and was not present in control samples. VWA3B encodes a von Willebrand Factor A Domain-Containing Protein 3B with ubiquitous expression, including the cerebellum. The viability of cultured cells expressing the specific K622T mutation was proved to decrease through the activation of apoptotic pathway. CONCLUSIONS Mutated VWA3B was found to be likely associated with cerebellar degeneration with intellectual disability. Although a rare cause of cerebellar degeneration, these findings indicate a critical role for VWA3B in the apoptosis pathway in neuronal tissues.
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Affiliation(s)
- Toshitaka Kawarai
- Department of Clinical Neuroscience, Institute of Biomedical Sciences, Tokushima University Graduate School, Tokushima, Japan
| | - Atsushi Tajima
- Department of Human Genetics, Institute of Biomedical Sciences, Tokushima University Graduate School, Tokushima, Japan Department of Bioinformatics and Genomics, Graduate School of Medical Sciences, Kanazawa University, Kanazawa, Japan
| | - Yukiko Kuroda
- Department of Clinical Research, Tokushima National Hospital, National Hospital Organization, Tokushima, Japan
| | - Naoki Saji
- Department of Stroke Medicine, Kawasaki Medical School, Kurashiki, Okayama, Japan
| | - Antonio Orlacchio
- Laboratorio di Neurogenetica, CERC-IRCCS Santa Lucia, Rome, Italy Dipartimento di Medicina dei Sistemi, Università di Roma "Tor Vergata", Rome, Italy
| | - Hideo Terasawa
- Department of Neurology, Hyogo Brain and Heart Centre, Himeji City, Hyogo, Japan
| | - Hirotaka Shimizu
- Department of Neurology, Hyogo Brain and Heart Centre, Himeji City, Hyogo, Japan
| | - Yasushi Kita
- Department of Neurology, Hyogo Brain and Heart Centre, Himeji City, Hyogo, Japan
| | - Yuishin Izumi
- Department of Clinical Neuroscience, Institute of Biomedical Sciences, Tokushima University Graduate School, Tokushima, Japan
| | - Takao Mitsui
- Department of Clinical Research, Tokushima National Hospital, National Hospital Organization, Tokushima, Japan
| | - Issei Imoto
- Department of Human Genetics, Institute of Biomedical Sciences, Tokushima University Graduate School, Tokushima, Japan
| | - Ryuji Kaji
- Department of Clinical Neuroscience, Institute of Biomedical Sciences, Tokushima University Graduate School, Tokushima, Japan
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Clinical and Neuropathological Features of Spastic Ataxia in a Spanish Family with Novel Compound Heterozygous Mutations in STUB1. THE CEREBELLUM 2016; 14:378-81. [PMID: 25592071 DOI: 10.1007/s12311-014-0643-7] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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Schisler JC, Patterson C, Willis MS. SKELETAL MUSCLE MITOCHONDRIAL ALTERATIONS IN CARBOXYL TERMINUS OF HSC70 INTERACTING PROTEIN (CHIP) -/- MICE. AFRICAN JOURNAL OF CELLULAR PATHOLOGY 2016; 6:28-36. [PMID: 28593200 PMCID: PMC5459302] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
AIM Hereditary ataxias are characterized by a slowly progressive loss of gait, hand, speech, and eye coordination and cerebellar atrophy. A subset of these, including hypogonadism, are inherited as autosomal recessive traits involving coding mutations of genes involved in ubiquitination including RNF216, OTUD4, and STUB1. Cerebellar CHIPopathy (MIM 615768) is a form of autosomal recessive spinocerebellar ataxia (SCAR16) and when accompanied with hypogonadism, clinically resembles the Gordon Holmes Syndrome (GHS). A causal missense mutation in the gene that encodes the carboxy terminus of HSP-70 interacting protein (CHIP) protein was reported for the first time in 2014. CHIP-/- mice were found to phenocopy the motor deficiencies and some aspects of the hypogonadism observed in patients with STUB1 mutations. However, mechanisms responsible for these deficits are not known. METHODS In a survey of skeletal muscle by transmission electron microscopy. RESULTS CHIP-/- mice at 6 months of age were found to have morphological changes consistent with increased sarcoplasmic reticulum compartments in quadriceps muscle and gastrocnemius (toxic oligomers and tubular aggregates), but not in soleus. CONCLUSION Since CHIP has been implicated in ER stress in non-muscle cells, these findings illustrate potential parallel roles of CHIP in the muscle sarcoplasmic reticulum, a hypothesis that may be clinically relevant in a variety of common muscular and cardiac diseases.
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Affiliation(s)
- Jonathan C. Schisler
- McAllister Heart Institute, University of North Carolina, Chapel Hill, NC USA
- Department of Pharmacology, University of North Carolina, Chapel Hill, NC USA
| | - Cam Patterson
- McAllister Heart Institute, University of North Carolina, Chapel Hill, NC USA
- Presbyterian Hospital/Weill-Cornell Medical Center, New York, New York, USA
| | - Monte S. Willis
- McAllister Heart Institute, University of North Carolina, Chapel Hill, NC USA
- Department of Pharmacology, University of North Carolina, Chapel Hill, NC USA
- Department of Pathology & Laboratory Medicine, University of North Carolina, Chapel Hill, NC USA
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Duan R, Shi Y, Yu L, Zhang G, Li J, Lin Y, Guo J, Wang J, Shen L, Jiang H, Wang G, Tang B. UBA5 Mutations Cause a New Form of Autosomal Recessive Cerebellar Ataxia. PLoS One 2016; 11:e0149039. [PMID: 26872069 PMCID: PMC4752235 DOI: 10.1371/journal.pone.0149039] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2015] [Accepted: 01/26/2016] [Indexed: 12/19/2022] Open
Abstract
Autosomal recessive cerebellar ataxia (ARCA) comprises a large and heterogeneous group of neurodegenerative disorders. For many affected patients, the genetic cause remains undetermined. Through whole-exome sequencing, we identified compound heterozygous mutations in ubiquitin-like modifier activating enzyme 5 gene (UBA5) in two Chinese siblings presenting with ARCA. Moreover, copy number variations in UBA5 or ubiquitin-fold modifier 1 gene (UFM1) were documented with the phenotypes of global developmental delays and gait disturbances in the ClinVar database. UBA5 encodes UBA5, the ubiquitin-activating enzyme of UFM1. However, a crucial role for UBA5 in human neurological disease remains to be reported. Our molecular study of UBA5-R246X revealed a dramatically decreased half-life and loss of UFM1 activation due to the absence of the catalytic cysteine Cys250. UBA5-K310E maintained its interaction with UFM1, although with less stability, which may affect the ability of this UBA5 mutant to activate UFM1. Drosophila modeling revealed that UBA5 knockdown induced locomotive defects and a shortened lifespan accompanied by aberrant neuromuscular junctions (NMJs). Strikingly, we found that UFM1 and E2 cofactor knockdown induced markedly similar phenotypes. Wild-type UBA5, but not mutant UBA5, significantly restored neural lesions caused by the absence of UBA5. The finding of a UBA5 mutation in cerebellar ataxia suggests that impairment of the UFM1 pathway may contribute to the neurological phenotypes of ARCA.
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Affiliation(s)
- Ranhui Duan
- The State Key Laboratory of Medical Genetics, School of Life Sciences, Central South University, Changsha, Hunan province, China
- * E-mail: (RD); (BT)
| | - Yuting Shi
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, Hunan province, China
| | - Li Yu
- The State Key Laboratory of Medical Genetics, School of Life Sciences, Central South University, Changsha, Hunan province, China
| | - Gehan Zhang
- The State Key Laboratory of Medical Genetics, School of Life Sciences, Central South University, Changsha, Hunan province, China
| | - Jia Li
- The State Key Laboratory of Medical Genetics, School of Life Sciences, Central South University, Changsha, Hunan province, China
| | - Yunting Lin
- The State Key Laboratory of Medical Genetics, School of Life Sciences, Central South University, Changsha, Hunan province, China
| | - Jifeng Guo
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, Hunan province, China
- The State Key Laboratory of Medical Genetics, School of Life Sciences, Central South University, Changsha, Hunan province, China
- The Key Laboratory of Hunan Province in Neurodegenerative Disorders, Central South University, Changsha, Hunan province, China
| | - Junling Wang
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, Hunan province, China
- The State Key Laboratory of Medical Genetics, School of Life Sciences, Central South University, Changsha, Hunan province, China
- The Key Laboratory of Hunan Province in Neurodegenerative Disorders, Central South University, Changsha, Hunan province, China
| | - Lu Shen
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, Hunan province, China
- The State Key Laboratory of Medical Genetics, School of Life Sciences, Central South University, Changsha, Hunan province, China
- The Key Laboratory of Hunan Province in Neurodegenerative Disorders, Central South University, Changsha, Hunan province, China
| | - Hong Jiang
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, Hunan province, China
- The State Key Laboratory of Medical Genetics, School of Life Sciences, Central South University, Changsha, Hunan province, China
- The Key Laboratory of Hunan Province in Neurodegenerative Disorders, Central South University, Changsha, Hunan province, China
| | - Guanghui Wang
- Department of Pharmacology, College of Pharmaceutical Sciences, Soochow University, Suzhou, Jiangsu province, China
| | - Beisha Tang
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, Hunan province, China
- The State Key Laboratory of Medical Genetics, School of Life Sciences, Central South University, Changsha, Hunan province, China
- The Key Laboratory of Hunan Province in Neurodegenerative Disorders, Central South University, Changsha, Hunan province, China
- * E-mail: (RD); (BT)
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Abstract
Autophagy is a major degradation system which processes substrates through the steps of autophagosome formation, autophagosome-lysosome fusion, and substrate degradation. Aberrant autophagic flux is present in many pathological conditions including neurodegeneration and tumors. CHIP/STUB1, an E3 ligase, plays an important role in neurodegeneration. In this study, we identified the regulation of autophagic flux by CHIP (carboxy-terminus of Hsc70-interacting protein). Knockdown of CHIP induced autophagosome formation through increasing the PTEN protein level and decreasing the AKT/mTOR activity as well as decreasing phosphorylation of ULK1 on Ser757. However, degradation of the autophagic substrate p62 was disturbed by knockdown of CHIP, suggesting an abnormality of autophagic flux. Furthermore, knockdown of CHIP increased the susceptibility of cells to autophagic cell death induced by bafilomycin A1. Thus, our data suggest that CHIP plays roles in the regulation of autophagic flux.
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Coutelier M, Stevanin G, Brice A. Genetic landscape remodelling in spinocerebellar ataxias: the influence of next-generation sequencing. J Neurol 2015; 262:2382-95. [DOI: 10.1007/s00415-015-7725-4] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2015] [Revised: 03/25/2015] [Accepted: 03/26/2015] [Indexed: 12/23/2022]
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Day FR, Perry JRB, Ong KK. Genetic Regulation of Puberty Timing in Humans. Neuroendocrinology 2015; 102:247-255. [PMID: 25968239 PMCID: PMC6309186 DOI: 10.1159/000431023] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/23/2015] [Accepted: 04/28/2015] [Indexed: 12/11/2022]
Abstract
Understanding the regulation of puberty timing has relevance to developmental and human biology and to the pathogenesis of various diseases. Recent large-scale genome-wide association studies on puberty timing and adult height, body mass index (BMI) and central body shape provide evidence for shared biological mechanisms that regulate these traits. There is a substantial genetic overlap between age at menarche in women and BMI, with almost invariable directional consistency with the epidemiological associations between earlier menarche and higher BMI. By contrast, the genetic loci identified for age at menarche are largely distinct from those identified for central body shape, while alleles that confer earlier menarche can be associated with taller or shorter adult height. The findings of population-based studies on age at menarche show increasing relevance for other studies of rare monogenic disorders and enrich our understanding of the mechanisms that regulate the timing of puberty and reproductive function.
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Affiliation(s)
- Felix R Day
- MRC Epidemiology Unit, Institute of Metabolic Science, University of Cambridge, Cambridge Biomedical Campus, Cambridge, UK
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Ronnebaum SM, Patterson C, Schisler JC. Emerging evidence of coding mutations in the ubiquitin-proteasome system associated with cerebellar ataxias. Hum Genome Var 2014; 1:14018. [PMID: 27081508 PMCID: PMC4785523 DOI: 10.1038/hgv.2014.18] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2014] [Revised: 08/20/2014] [Accepted: 08/28/2014] [Indexed: 12/14/2022] Open
Abstract
Cerebellar ataxia (CA) is a disorder associated with impairments in balance, coordination, and gait caused by degeneration of the cerebellum. The mutations associated with CA affect functionally diverse genes; furthermore, the underlying genetic basis of a given CA is unknown in many patients. Exome sequencing has emerged as a cost-effective technology to discover novel genetic mutations, including autosomal recessive CA (ARCA). Five recent studies that describe how exome sequencing performed on a diverse pool of ARCA patients revealed 14 unique mutations in STUB1, a gene that encodes carboxy terminus of Hsp70-interacting protein (CHIP). CHIP mediates protein quality control through chaperone and ubiquitin ligase activities and is implicated in alleviating proteotoxicity in several neurodegenerative diseases. However, these recent studies linking STUB1 mutations to various forms of ataxia are the first indications that CHIP is directly involved in the progression of a human disease. Similar exome-sequencing studies have revealed novel mutations in ubiquitin-related proteins associated with CA and other neurological disorders. This review provides an overview of CA, describes the benefits and limitations of exome sequencing, outlines newly discovered STUB1 mutations, and theorizes on how CHIP and other ubiquitin-related proteins function to prevent neurological deterioration.
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Affiliation(s)
- Sarah M Ronnebaum
- McAllister Heart Institute, The University of North Carolina at Chapel Hill , Chapel Hill, NC, USA
| | - Cam Patterson
- Presbyterian Hospital/Weill-Cornell Medical Center , New York, NY, USA
| | - Jonathan C Schisler
- McAllister Heart Institute, The University of North Carolina at Chapel Hill, Chapel Hill, NC, USA; Department of Pharmacology, The University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
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Heimdal K, Sanchez-Guixé M, Aukrust I, Bollerslev J, Bruland O, Jablonski GE, Erichsen AK, Gude E, Koht JA, Erdal S, Fiskerstrand T, Haukanes BI, Boman H, Bjørkhaug L, Tallaksen CME, Knappskog PM, Johansson S. STUB1 mutations in autosomal recessive ataxias - evidence for mutation-specific clinical heterogeneity. Orphanet J Rare Dis 2014; 9:146. [PMID: 25258038 PMCID: PMC4181732 DOI: 10.1186/s13023-014-0146-0] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2014] [Accepted: 09/08/2014] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND A subset of hereditary cerebellar ataxias is inherited as autosomal recessive traits (ARCAs). Classification of recessive ataxias due to phenotypic differences in the cerebellum and cerebellar structures is constantly evolving due to new identified disease genes. Recently, reports have linked mutations in genes involved in ubiquitination (RNF216, OTUD4, STUB1) to ARCA with hypogonadism. METHODS AND RESULTS With a combination of homozygozity mapping and exome sequencing, we identified three mutations in STUB1 in two families with ARCA and cognitive impairment; a homozygous missense variant (c.194A > G, p.Asn65Ser) that segregated in three affected siblings, and a missense change (c.82G > A, p.Glu28Lys) which was inherited in trans with a nonsense mutation (c.430A > T, p.Lys144Ter) in another patient. STUB1 encodes CHIP (C-terminus of Heat shock protein 70 - Interacting Protein), a dual function protein with a role in ubiquitination as a co-chaperone with heat shock proteins, and as an E3 ligase. We show that the p.Asn65Ser substitution impairs CHIP's ability to ubiquitinate HSC70 in vitro, despite being able to self-ubiquitinate. These results are consistent with previous studies highlighting this as a critical residue for the interaction between CHIP and its co-chaperones. Furthermore, we show that the levels of CHIP are strongly reduced in vivo in patients' fibroblasts compared to controls. CONCLUSIONS These results suggest that STUB1 mutations might cause disease by impacting not only the E3 ligase function, but also its protein interaction properties and protein amount. Whether the clinical heterogeneity seen in STUB1 ARCA can be related to the location of the mutations remains to be understood, but interestingly, all siblings with the p.Asn65Ser substitution showed a marked appearance of accelerated aging not previously described in STUB1 related ARCA, none display hormonal aberrations/clinical hypogonadism while some affected family members had diabetes, alopecia, uveitis and ulcerative colitis, further refining the spectrum of STUB1 related disease.
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Sun ZF, Zhang YH, Guo JF, Sun QY, Mei JP, Zhou HL, Guan LP, Tian JY, Hu ZM, Li JD, Xia K, Yan XX, Tang BS. Genetic diagnosis of two dopa-responsive dystonia families by exome sequencing. PLoS One 2014; 9:e106388. [PMID: 25181484 PMCID: PMC4152247 DOI: 10.1371/journal.pone.0106388] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2013] [Accepted: 08/06/2014] [Indexed: 11/18/2022] Open
Abstract
Dopa-responsive dystonia, a rare disorder typically presenting in early childhood with lower limb dystonia and gait abnormality, responds well to levodopa. However, it is often misdiagnosed with the wide spectrum of phenotypes. By exome sequencing, we make a rapid genetic diagnosis for two atypical dopa-responsive dystonia pedigrees. One pedigree, presented with prominent parkinsonism, was misdiagnosed as Parkinson's disease until a known mutation in GCH1 (GTP cyclohydrolase 1) gene (NM_000161.2: c.631_632delAT, p.Met211ValfsX38) was found. The other pedigree was detected with a new compound heterozygous mutation in TH (tyrosine hydroxylase) gene [(NM_000360.3: c.911C>T, p.Ala304Val) and (NM_000360.3: c.1358G>A, p.Arg453His)], whose proband, a pregnant woman, required a rapid and less-biased genetic diagnosis. In conclusion, we demonstrated that exome sequencing could provide a precise and rapid genetic testing in the diagnosis of Mendelian diseases, especially for diseases with wide phenotypes.
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Affiliation(s)
- Zhan-fang Sun
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, China
| | - Yu-han Zhang
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, China
| | - Ji-feng Guo
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, China
- Key Laboratory of Hunan Province in Neurodegenerative Disorders, Central South University, Changsha, China
| | - Qi-ying Sun
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, China
| | | | | | | | - Jin-yong Tian
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, China
| | - Zheng-mao Hu
- State Key Laboratory of Medical Genetics, Central South University, Changsha, China
| | - Jia-da Li
- State Key Laboratory of Medical Genetics, Central South University, Changsha, China
| | - Kun Xia
- State Key Laboratory of Medical Genetics, Central South University, Changsha, China
| | - Xin-xiang Yan
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, China
- Key Laboratory of Hunan Province in Neurodegenerative Disorders, Central South University, Changsha, China
| | - Bei-sha Tang
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, China
- Key Laboratory of Hunan Province in Neurodegenerative Disorders, Central South University, Changsha, China
- State Key Laboratory of Medical Genetics, Central South University, Changsha, China
- * E-mail:
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Ronnebaum SM, Patterson C, Schisler JC. Minireview: hey U(PS): metabolic and proteolytic homeostasis linked via AMPK and the ubiquitin proteasome system. Mol Endocrinol 2014; 28:1602-15. [PMID: 25099013 DOI: 10.1210/me.2014-1180] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
One of the master regulators of both glucose and lipid cellular metabolism is 5'-AMP-activated protein kinase (AMPK). As a metabolic pivot that dynamically responds to shifts in nutrient availability and stress, AMPK dysregulation is implicated in the underlying molecular pathology of a variety of diseases, including cardiovascular diseases, diabetes, cancer, neurological diseases, and aging. Although the regulation of AMPK enzymatic activity by upstream kinases is an active area of research, less is known about regulation of AMPK protein stability and activity by components of the ubiquitin-proteasome system (UPS), the cellular machinery responsible for both the recognition and degradation of proteins. Furthermore, there is growing evidence that AMPK regulates overall proteasome activity and individual components of the UPS. This review serves to identify the current understanding of the interplay between AMPK and the UPS and to promote further exploration of the relationship between these regulators of energy use and amino acid availability within the cell.
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Affiliation(s)
- Sarah M Ronnebaum
- McAllister Heart Institute (S.M.R., J.C.S.) and Department of Pharmacology (J.C.S.), The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599; and Presbyterian Hospital/Weill-Cornell Medical Center (C.P.), New York, New York 10065
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MacGurn JA. Garbage on, garbage off: new insights into plasma membrane protein quality control. Curr Opin Cell Biol 2014; 29:92-8. [PMID: 24908345 DOI: 10.1016/j.ceb.2014.05.001] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2014] [Revised: 04/10/2014] [Accepted: 05/10/2014] [Indexed: 01/22/2023]
Abstract
Maintenance of cellular protein quality - by restoring misfolded proteins to their native state and by targeting terminally misfolded or damaged proteins for degradation - is a critical function of all cells. To ensure protein quality, cells have evolved various organelle-specific quality control mechanisms responsible for recognizing and responding to misfolded proteins at different subcellular locations of the cell. Recently, several publications have begun to elucidate mechanisms of quality control that operate at the plasma membrane (PM), recognizing misfolded PM proteins and targeting their endocytic trafficking and lysosomal degradation. Here, I discuss these recent developments in our understanding of PM quality control mechanisms and how they relate to global protein quality control strategies in the cell.
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Affiliation(s)
- Jason A MacGurn
- Department of Cell and Developmental Biology, Vanderbilt University Medical Center, Nashville, TN 37232-8240, USA.
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Synofzik M, Schüle R, Schulze M, Gburek-Augustat J, Schweizer R, Schirmacher A, Krägeloh-Mann I, Gonzalez M, Young P, Züchner S, Schöls L, Bauer P. Phenotype and frequency of STUB1 mutations: next-generation screenings in Caucasian ataxia and spastic paraplegia cohorts. Orphanet J Rare Dis 2014; 9:57. [PMID: 24742043 PMCID: PMC4021831 DOI: 10.1186/1750-1172-9-57] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2014] [Accepted: 04/11/2014] [Indexed: 02/02/2023] Open
Abstract
Background Mutations in the gene STUB1, encoding the protein CHIP (C-terminus of HSC70-interacting protein), have recently been suggested as a cause of recessive ataxia based on the findings in few Chinese families. Here we aimed to investigate the phenotypic and genotypic spectrum of STUB1 mutations, and to assess their frequency in different Caucasian disease cohorts. Methods 300 subjects with degenerative ataxia (n = 167) or spastic paraplegia (n = 133) were screened for STUB1 variants by whole-exome-sequencing (n = 204) or shotgun-fragment-library-sequencing (n = 96). To control for the specificity of STUB1 variants, we screened an additional 1707 exomes from 891 index families with other neurological diseases. Results We identified 3 ataxia patients (3/167 = 1.8%) with 4 novel missense mutations in STUB1, including 3 mutations in its tetratricopeptide-repeat domain. All patients showed evidence of pyramidal tract damage. Cognitive impairment was present only in one and hypogonadism in none of them. Ataxia did not start before age 48 years in one subject. No recessive STUB1 variants were identified in families with other neurological diseases, demonstrating that STUB1 variants are not simply rare polymorphisms ubiquitous in neurodegenerative disease. Conclusions STUB1-disease occurs also in Caucasian ataxia populations (1.8%). Our results expand the genotypic spectrum of STUB1-disease, showing that pathogenic mutations affect also the tetratricopeptide-repeat domain, thus providing clinical evidence for the functional importance of this domain. Moreover, they further delineate the phenotypic core features of STUB1-ataxia. Pyramidal tract damage is a common accompanying feature and can include lower limb spasticity, thus adding STUB1-ataxia to the differential diagnosis of “spastic ataxias”. However, STUB1 is rare in subjects with predominant spastic paraplegia (0/133). In contrast to previous reports, STUB1-ataxia can start even above age 40 years, and neither hypogonadism nor prominent cognitive impairment are obligatory features.
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Affiliation(s)
- Matthis Synofzik
- Department of Neurodegenerative Diseases, Hertie-Institute for Clinical Brain Research, University of Tübingen, Hoppe-Seyler-Str, 3, 72076 Tübingen, Germany.
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