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Faheem A, Masud R, Nasir R, Awan ZK, Nasir HA, Khan ZK, Fayyaz H, Raza SI. Exome sequencing revealed variants in SGCA and SIL1 genes underlying limb girdle muscular dystrophy and Marinesco-Sjögren syndrome patients. Mol Biol Rep 2024; 51:853. [PMID: 39060875 DOI: 10.1007/s11033-024-09746-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2024] [Accepted: 06/20/2024] [Indexed: 07/28/2024]
Abstract
BACKGROUND Inherited neuromuscular (NMD) and neurodegenerative diseases (NDD) belong to two distinct categories that disturb different components of the nervous system, leading to a variety of different symptoms and clinical manifestations. Both NMD and NDD are a heterogeneous group of genetic conditions. Genetic variations in the SGCA and SIL1 genes have been implicated in causing Limb Girdle Muscular Dystrophy (LGMD), a type of neuromuscular disorder, and Marinesco-Sjögren Syndrome (MSS) which is a neurodegenerative disorder. METHODS In the present study, we have investigated four patients presenting LGMD and five patients with MSS features. After collecting detailed clinical and family history, necessary laboratory investigations, including estimation of a skeletal muscle marker enzyme serum creatine kinase (CK), nerve conduction study (NCS), electromyography (EMG), echocardiography (Echo), Magnetic resonance imaging (MRI -brain), CT-brain and X-rays were performed. Whole exome followed by Sanger sequencing was employed to search for the disease-causing variants. RESULTS Physical examination in LGMD patients revealed poor muscle tone and facing difficulty in straightening up from the floor. Clinical history revealed frequent falls and strenuousness in climbing stairs. They started toe-walking in early childhood. Laboratory investigations confirmed elevated CK levels and abnormal NCS and EMG. The MSS patients showed abnormalities in gate and jerking movement, abnormal speech, and strabismus with cataract. MRI-brain showed cerebral atrophy in some MSS patients with elevated CK levels. Whole exome sequencing revealed a nonsense variant [c.C574T, p.(Arg192*)] in the SGCA gene and a frameshift [c.936dupG, p.(Leu313AlaFs*39)] in the SIL1 gene in LGMD and MSS patients, respectively. CONCLUSION Our study emphasizes the significance of integrating clinical and genetic analyses for precise diagnosis and tailored management strategies in inherited NMD and NDD disorders. To the best of our knowledge, this is the first study documenting SGCA and SIL1 recurrent variants in subcontinent populations with few rare clinical features. The recurrent mutations expanding the global understanding of the mutation's geographic and ethnic distribution and contributing valuable epidemiological data. The study will facilitate genetic counseling for families experiencing similar clinical features, both within Pakistani populations and in other regions.
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Affiliation(s)
- Ali Faheem
- Department of Biochemistry, Sanquan College of Xinxiang Medical University, Xinxiang, Henan, China
| | - Rizwan Masud
- Department of Physiology, Rai Medical College, Sargodha, Punjab, Pakistan
| | - Rabea Nasir
- Department of Physiology, M. Islam Medical College, Gujranwala, Pakistan
| | - Zeeshan Khalid Awan
- Department of Pathology, Rawal Institute of Health Sciences, Islamabad, Pakistan
| | - Hammad Ali Nasir
- Department of Paediatrics, Khalida Safdar Memorial Hospital, Rawalpindi, Pakistan
- Department of Biochemistry, Faculty of Biological Sciences, Quaid-i-Azam University, Islamabad, 45320, Pakistan
| | - Zara Khalid Khan
- Department of Biochemistry, Faculty of Biological Sciences, Quaid-i-Azam University, Islamabad, 45320, Pakistan
- Department of Biochemistry, Shaheed Zulfiqar Ali Bhutto Medical University,, Rawal Institute of Health Sciences, Islamabad, Pakistan
| | - Hajra Fayyaz
- Department of Biochemistry, Faculty of Biological Sciences, Quaid-i-Azam University, Islamabad, 45320, Pakistan
| | - Syed Irfan Raza
- Department of Biochemistry, Faculty of Biological Sciences, Quaid-i-Azam University, Islamabad, 45320, Pakistan.
- Department of Biochemistry, HBS Medical College, Islamabad, Pakistan.
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2
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Bayram N, Kaçar Bayram A, Daimagüler HS, Salimi Dafsari H, Bamborschke D, Uyanik G, Erdogan M, Özsaygılı C, Pangal E, Yuvaci İ, Doğanay S, Gümüş H, Per H, Jungbluth H, Çırak S. Genotype-phenotype correlations in ocular manifestations of Marinesco-Sjögren syndrome: Case report and literature review. Eur J Ophthalmol 2021; 32:NP92-NP97. [PMID: 34075802 DOI: 10.1177/11206721211021291] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
PURPOSE This study aims to present a family with two children with MSS who presented with different ophthalmic features. We also aim to review MSS patients' ocular manifestations to provide a basis for future clinical trials and improve MSS patients' ophthalmologic care. CASE DESCRIPTION Both patients presented with global developmental delay, microcephaly, cerebellar ataxia, and myopathy. The older sibling had developed bilateral cataracts at the age of six. Her 2 years younger sister interestingly showed bilateral hyperopic refractive error without cataracts yet. Mendeliome sequencing unraveled a novel homozygous frameshift mutation in the SIL1 gene (SIL1, NM_022464.5, c.1042dupG, p.E348Gfs*4), causing MSS. A systematic literature review revealed that cataracts appear in 96% of MSS cases with a mean onset at 3.2 years. Additional frequent ocular features were strabismus (51.6%) and nystagmus (45.2%). CONCLUSION SIL1-related MSS is associated with marked clinical variability. Cataracts can develop later than neuromuscular features and cognitive signs. Since cataract is a relatively late finding, patients may refer to ophthalmologists for other reasons such as refractive errors, strabismus, or nystagmus. Molecular genetic testing for SIL1 is essential to facilitate early diagnosis in patients with suspected MSS.
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Affiliation(s)
- Nurettin Bayram
- Department of Ophthalmology, University of Health Sciences, Kayseri City Training and Research Hospital, Kayseri, Turkey
| | - Ayşe Kaçar Bayram
- Department of Pediatric Neurology, University of Health Sciences, Kayseri City Training and Research Hospital, Kayseri, Turkey
| | - Hülya-Sevcan Daimagüler
- Department of Pediatrics, Faculty of Medicine and University Hospital Cologne, University of Cologne, Cologne, Germany.,Center for Molecular Medicine, Faculty of Medicine and University Hospital Cologne, University of Cologne, Cologne, Germany
| | - Hormos Salimi Dafsari
- Department of Pediatrics, Faculty of Medicine and University Hospital Cologne, University of Cologne, Cologne, Germany.,Center for Molecular Medicine, Faculty of Medicine and University Hospital Cologne, University of Cologne, Cologne, Germany
| | - Daniel Bamborschke
- Department of Pediatrics, Faculty of Medicine and University Hospital Cologne, University of Cologne, Cologne, Germany.,Center for Molecular Medicine, Faculty of Medicine and University Hospital Cologne, University of Cologne, Cologne, Germany
| | - Gökhan Uyanik
- Center for Medical Genetics, Hanusch Hospital, Vienna, Austria.,Medical Faculty, Sigmund Freud University, Vienna, Austria
| | - Murat Erdogan
- Department of Medical Genetics, University of Health Sciences, Kayseri Training and Research Hospital, Kayseri, Turkey
| | - Cemal Özsaygılı
- Department of Ophthalmology, University of Health Sciences, Kayseri City Training and Research Hospital, Kayseri, Turkey
| | - Emine Pangal
- Department of Ophthalmology, University of Health Sciences, Kayseri City Training and Research Hospital, Kayseri, Turkey
| | - İsa Yuvaci
- Department of Ophthalmology, University of Health Sciences, Kayseri City Training and Research Hospital, Kayseri, Turkey
| | - Selim Doğanay
- Erciyes University, School of Medicine, Department of Radiology, Division of Pediatric Radiology, Kayseri, Turkey
| | - Hakan Gümüş
- Department of Pediatrics, Erciyes University, School of Medicine, Division of Pediatric Neurology, Kayseri, Turkey
| | - Hüseyin Per
- Department of Pediatrics, Erciyes University, School of Medicine, Division of Pediatric Neurology, Kayseri, Turkey
| | - Heinz Jungbluth
- Department of Paediatric Neurology - Neuromuscular Service, Evelina Children's Hospital, Guy's & St Thomas' NHS Foundation Trust, London, UK.,Department of Basic and Clinical Neuroscience, IoPPN, London, UK.,Randall Division of Cell and Molecular Biophysics, Muscle Signaling Section, King's College London, London, UK
| | - Sebahattin Çırak
- Department of Pediatrics, Faculty of Medicine and University Hospital Cologne, University of Cologne, Cologne, Germany.,Center for Molecular Medicine, Faculty of Medicine and University Hospital Cologne, University of Cologne, Cologne, Germany
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3
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Ichhaporia VP, Hendershot LM. Role of the HSP70 Co-Chaperone SIL1 in Health and Disease. Int J Mol Sci 2021; 22:ijms22041564. [PMID: 33557244 PMCID: PMC7913895 DOI: 10.3390/ijms22041564] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2021] [Revised: 01/30/2021] [Accepted: 01/30/2021] [Indexed: 12/04/2022] Open
Abstract
Cell surface and secreted proteins provide essential functions for multicellular life. They enter the endoplasmic reticulum (ER) lumen co-translationally, where they mature and fold into their complex three-dimensional structures. The ER is populated with a host of molecular chaperones, associated co-factors, and enzymes that assist and stabilize folded states. Together, they ensure that nascent proteins mature properly or, if this process fails, target them for degradation. BiP, the ER HSP70 chaperone, interacts with unfolded client proteins in a nucleotide-dependent manner, which is tightly regulated by eight DnaJ-type proteins and two nucleotide exchange factors (NEFs), SIL1 and GRP170. Loss of SIL1′s function is the leading cause of Marinesco-Sjögren syndrome (MSS), an autosomal recessive, multisystem disorder. The development of animal models has provided insights into SIL1′s functions and MSS-associated pathologies. This review provides an in-depth update on the current understanding of the molecular mechanisms underlying SIL1′s NEF activity and its role in maintaining ER homeostasis and normal physiology. A precise understanding of the underlying molecular mechanisms associated with the loss of SIL1 may allow for the development of new pharmacological approaches to treat MSS.
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4
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Chiesa R, Sallese M. Review: Protein misfolding diseases – the rare case of Marinesco‐Sjögren syndrome. Neuropathol Appl Neurobiol 2020; 46:323-343. [DOI: 10.1111/nan.12588] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2019] [Accepted: 11/03/2019] [Indexed: 12/15/2022]
Affiliation(s)
- R. Chiesa
- Department of Neuroscience Istituto di Ricerche Farmacologiche Mario Negri IRCCS MilanItaly
| | - M. Sallese
- Department of Medical, Oral and Biotechnological Sciences University "G. d'Annunzio" Chieti Italy
- CeSI‐MeT Center for Research on Ageing and Translational Medicine University "G. d'Annunzio" Chieti Italy
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5
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Functional Role of SIL1 in Neurodevelopment and Learning. Neural Plast 2019; 2019:9653024. [PMID: 31531014 PMCID: PMC6720716 DOI: 10.1155/2019/9653024] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2019] [Revised: 06/02/2019] [Accepted: 07/01/2019] [Indexed: 11/17/2022] Open
Abstract
Background Sil1 is the causative gene of Marinesco-Sjӧgren Syndrome (MSS). The mutated Sil1 generates shortened SIL1 protein which will form aggregation and be degraded rapidly. Mental retardation is a major symptom of MSS which suggests a role of SIL1 in the development of the central nervous system, but how SIL1 functions remains unclear. Objectives The aim of this study is to explore the role of SIL1 in regulating cerebral development and its underlying molecular mechanism. Methods The basic expression pattern of SIL1 in tissues and cultured cortical neurons is measured by immunostaining and Western blot. The expression of SIL1 is reduced in vitro and in vivo through RNA interference delivered by a lentivirus. The expression of NMDA receptor subunits and the function of the Reelin signaling pathway are then examined by surface biotinylation and Western blot subsequently. Finally, the spatial learning of young mice was assessed by the Barnes maze task. Results SIL1 deficiency caused a diminished expression of both Reelin receptors and therefore impaired the Reelin signaling pathway. It then inhibited the developmental expression of GluN2A and impaired the spatial learning of 5-week-old mice. Conclusions These results suggested that SIL1 is required for the development of the central nervous system which is associated with its role in Reelin signaling.
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6
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Gatz C, Hathazi D, Münchberg U, Buchkremer S, Labisch T, Munro B, Horvath R, Töpf A, Weis J, Roos A. Identification of Cellular Pathogenicity Markers for SIL1 Mutations Linked to Marinesco-Sjögren Syndrome. Front Neurol 2019; 10:562. [PMID: 31258504 PMCID: PMC6587064 DOI: 10.3389/fneur.2019.00562] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2018] [Accepted: 05/10/2019] [Indexed: 12/13/2022] Open
Abstract
Background and objective: Recessive mutations in the SIL1 gene cause Marinesco-Sjögren syndrome (MSS), a rare neuropediatric disorder. MSS-patients typically present with congenital cataracts, intellectual disability, cerebellar ataxia and progressive vacuolar myopathy. However, atypical clinical presentations associated with SIL1 mutations have been described over the last years; compound heterozygosity of SIL1 missense mutations even resulted in a phenotype not fulfilling the clinical diagnostic criteria of MSS. Thus, a read-out system to evaluate reliably the pathogenicity of amino acid changes in SIL1 is needed. Here, we aim to provide suitable cellular biomarkers enabling the robust evaluation of pathogenicity of SIL1 mutations. Methods: Five SIL1 variants including one polymorphism (p.K132Q), three known pathogenic mutations (p.V231_I232del, p.G312R, and p.L457P) and one ambiguous missense variant (p.R92W) were studied along with the wild-type proteins in Hek293 in vitro models by cell biological assays, immunoprecipitation, immunoblotting, and immunofluorescence as well as electron microscopy. Moreover, the SIL1-interactomes were interrogated by tandem-affinity-purification and subsequent mass spectrometry. Results: Our combined studies confirmed the pathogenicity of p.V231_I232del, p.G312R, and p.L457P by showing instability of the proteins as well as tendency to form aggregates. This observation is in line with altered structure of the ER-Golgi system and vacuole formation upon expression of these pathogenic SIL1-mutants as well as the presence of oxidative or ER-stress. Reduced cellular fitness along with abnormal mitochondrial architecture could also be observed. Notably, both the polymorphic p.K132Q and the ambiguous p.R92W variants did not elicit such alterations. Study of the SIL1-interactome identified POC1A as a novel binding partner of wild-type SIL1; the interaction is disrupted upon the presence of pathogenic mutants but not influenced by the presence of benign variants. Disrupted SIL1-POC1A interaction is associated with centrosome disintegration. Conclusions: We developed a combination of cellular outcome measures to evaluate the pathogenicity of SIL1 variants in suitable in vitro models and demonstrated that the p. R92W missense variant is a polymorphism rather than a pathogenic mutation leading to MSS.
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Affiliation(s)
- Christian Gatz
- Institute of Neuropathology, RWTH Aachen University Hospital, Aachen, Germany
| | - Denisa Hathazi
- Leibniz-Institut für Analytische Wissenschaften-ISAS-e.V., Dortmund, Germany.,Department of Clinical Neuroscience, University of Cambridge, Cambridge, United Kingdom
| | - Ute Münchberg
- Leibniz-Institut für Analytische Wissenschaften-ISAS-e.V., Dortmund, Germany
| | - Stephan Buchkremer
- Institute of Neuropathology, RWTH Aachen University Hospital, Aachen, Germany
| | - Thomas Labisch
- Institute of Neuropathology, RWTH Aachen University Hospital, Aachen, Germany
| | - Ben Munro
- Department of Clinical Neuroscience, University of Cambridge, Cambridge, United Kingdom
| | - Rita Horvath
- Department of Clinical Neuroscience, University of Cambridge, Cambridge, United Kingdom
| | - Ana Töpf
- International Centre for Life, Institute of Genetic Medicine, Newcastle upon Tyne, United Kingdom
| | - Joachim Weis
- Institute of Neuropathology, RWTH Aachen University Hospital, Aachen, Germany
| | - Andreas Roos
- Institute of Neuropathology, RWTH Aachen University Hospital, Aachen, Germany.,Leibniz-Institut für Analytische Wissenschaften-ISAS-e.V., Dortmund, Germany.,Pediatric Neurology, Faculty of Medicine, University Childrens Hospital, University of Duisburg-Essen, Essen, Germany
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7
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Ichhaporia VP, Kim J, Kavdia K, Vogel P, Horner L, Frase S, Hendershot LM. SIL1, the endoplasmic-reticulum-localized BiP co-chaperone, plays a crucial role in maintaining skeletal muscle proteostasis and physiology. Dis Model Mech 2018; 11:dmm.033043. [PMID: 29666155 PMCID: PMC5992605 DOI: 10.1242/dmm.033043] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2017] [Accepted: 03/22/2018] [Indexed: 01/02/2023] Open
Abstract
Mutations in SIL1, a cofactor for the endoplasmic reticulum (ER)-localized Hsp70 chaperone, BiP, cause Marinesco-Sjögren syndrome (MSS), an autosomal recessive disorder. Using a mouse model, we characterized molecular aspects of the progressive myopathy associated with MSS. Proteomic profiling of quadriceps at the onset of myopathy revealed that SIL1 deficiency affected multiple pathways critical to muscle physiology. We observed an increase in ER chaperones prior to the onset of muscle weakness, which was complemented by upregulation of multiple components of cellular protein degradation pathways. These responses were inadequate to maintain normal expression of secretory pathway proteins, including insulin and IGF-1 receptors. There was a paradoxical enhancement of downstream PI3K-AKT-mTOR signaling and glucose uptake in SIL1-disrupted skeletal muscles, all of which were insufficient to maintain skeletal muscle mass. Together, these data reveal a disruption in ER homeostasis upon SIL1 loss, which is countered by multiple compensatory responses that are ultimately unsuccessful, leading to trans-organellar proteostasis collapse and myopathy. Editor's choice: This study provides molecular insights into the progressive myopathy and cellular compensatory responses attempted upon loss of SIL1, a component of the endoplasmic-reticulum-resident Hsp70 protein-folding machinery.
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Affiliation(s)
- Viraj P Ichhaporia
- Dept of Microbiology, Immunology, and Biochemistry, The University of Tennessee Health Science Center, Memphis, TN 38163, USA.,Dept of Tumor Cell Biology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - Jieun Kim
- Small Animal Imaging Center, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - Kanisha Kavdia
- Proteomics Facility, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - Peter Vogel
- Dept of Pathology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - Linda Horner
- Cell and Tissue Imaging Center, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - Sharon Frase
- Cell and Tissue Imaging Center, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - Linda M Hendershot
- Dept of Microbiology, Immunology, and Biochemistry, The University of Tennessee Health Science Center, Memphis, TN 38163, USA .,Dept of Tumor Cell Biology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
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8
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Boltshauser E, Weber KP. Laboratory investigations. HANDBOOK OF CLINICAL NEUROLOGY 2018; 154:287-298. [PMID: 29903445 DOI: 10.1016/b978-0-444-63956-1.00017-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
This chapter deals with chemical and hematologic investigations which are often considered in the diagnostic workup of subacute to chronic cerebellar ataxias. Relevant investigations in blood (serum, plasma), urine, and cerebrospinal fluid are discussed. Particular attention is paid to early diagnosis of treatable metabolic ataxias (such as abetalipoproteinemia, coenzyme Q10 deficiency, cerebrotendinous xanthomatosis, glucose transporter type 1 deficiency, Refsum disease, and vitamin E deficiency), but autoimmune ataxias, other vitamin deficiencies, and endocrine disorders should also be kept in mind. Adequate interpretation of test results has to consider age-specific reference values. The selection of investigations should mainly be driven by the overall clinical context, considering gender, history, age, and mode of presentation, cerebellar and other neurologic as well as extraneurologic findings.
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Affiliation(s)
- Eugen Boltshauser
- Department of Pediatric Neurology, University Children's Hospital, University of Zurich, Zurich, Switzerland; Departments of Neurology and Ophthalmology, University Hospital Zurich, University of Zurich, Switzerland.
| | - Konrad P Weber
- Department of Pediatric Neurology, University Children's Hospital, University of Zurich, Zurich, Switzerland; Departments of Neurology and Ophthalmology, University Hospital Zurich, University of Zurich, Switzerland
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9
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Abstract
The autosomal-recessive cerebellar ataxias comprise more than half of the known genetic forms of ataxia and represent an extensive group of clinically heterogeneous disorders that can occur at any age but whose onset is typically prior to adulthood. In addition to ataxia, patients often present with polyneuropathy and clinical symptoms outside the nervous system. The most common of these diseases is Friedreich ataxia, caused by mutation of the frataxin gene, but recent advances in genetic analysis have greatly broadened the ever-expanding number of causative genes to over 50. In this review, the clinical neurogenetics of the recessive cerebellar ataxias will be discussed, including updates on recently identified novel ataxia genes, advancements in unraveling disease-specific molecular pathogenesis leading to ataxia, potential treatments under development, technologic improvements in diagnostic testing such as clinical exome sequencing, and what the future holds for clinicians and geneticists.
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Affiliation(s)
- Brent L Fogel
- Program in Neurogenetics, Departments of Neurology and Human Genetics, David Geffen School of Medicine, University of California, Los Angeles, CA, United States.
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10
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Kollipara L, Buchkremer S, Coraspe JAG, Hathazi D, Senderek J, Weis J, Zahedi RP, Roos A. In-depth phenotyping of lymphoblastoid cells suggests selective cellular vulnerability in Marinesco-Sjögren syndrome. Oncotarget 2017; 8:68493-68516. [PMID: 28978133 PMCID: PMC5620273 DOI: 10.18632/oncotarget.19663] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2016] [Accepted: 05/28/2017] [Indexed: 12/18/2022] Open
Abstract
SIL1 is a ubiquitous protein of the Endoplasmic Reticulum (ER) acting as a co-chaperone for the ER-resident chaperone, BiP. Recessive mutations of the corresponding gene lead to vulnerability of skeletal muscle and central nervous system in man (Marinesco-Sjögren syndrome; MSS) and mouse. However, it is still unclear how loss of ubiquitous SIL1 leads to selective vulnerability of the nervous system and skeletal muscle whereas other cells and organs are protected from clinical manifestations. In this study we aimed to disentangle proteins participating in selective vulnerability of SIL1-deficient cells and tissues: morphological examination of MSS patient-derived lymphoblastoid cells revealed altered organelle structures (ER, nucleus and mitochondria) thus showing subclinical vulnerability. To correlate structural perturbations with biochemical changes and to identify proteins potentially preventing phenotypical manifestation, proteomic studies have been carried out. Results of proteomic profiling are in line with the morphological findings and show affection of nuclear, mitochondrial and cytoskeletal proteins as well as of such responsible for cellular viability. Moreover, expression patterns of proteins known to be involved in neuromuscular disorders or in development and function of the nervous system were altered. Paradigmatic findings were confirmed by immunohistochemistry of splenic lymphocytes and the cerebellum of SIL1-deficient mice. Ataxin-10, identified with increased abundance in our proteome profile, is necessary for the neuronal survival but also controls muscle fiber apoptosis, thus declaring this protein as a plausible candidate for selective tissue vulnerability. Our combined results provide first insights into the molecular causes of selective cell and tissue vulnerability defining the MSS phenotype.
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Affiliation(s)
- Laxmikanth Kollipara
- Leibniz-Institut für Analytische Wissenschaften-ISAS -e.V., 44227 Dortmund, Germany
| | - Stephan Buchkremer
- Institute of Neuropathology, University Hospital Aachen, RWTH Aachen, 5274 Aachen, Germany
| | | | - Denisa Hathazi
- Leibniz-Institut für Analytische Wissenschaften-ISAS -e.V., 44227 Dortmund, Germany
| | - Jan Senderek
- Friedrich-Baur-Institute, Medical Faculty, Ludwig-Maximilians-University, 80336 Munich, Germany
| | - Joachim Weis
- Institute of Neuropathology, University Hospital Aachen, RWTH Aachen, 5274 Aachen, Germany
| | - René P Zahedi
- Leibniz-Institut für Analytische Wissenschaften-ISAS -e.V., 44227 Dortmund, Germany
| | - Andreas Roos
- Leibniz-Institut für Analytische Wissenschaften-ISAS -e.V., 44227 Dortmund, Germany.,Institute of Neuropathology, University Hospital Aachen, RWTH Aachen, 5274 Aachen, Germany.,The John Walton Muscular Dystrophy Research Centre, MRC Centre for Neuromuscular Diseases, Newcastle University, Newcastle upon Tyne, NE1 3BZ, UK
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11
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Siegenthaler KD, Pareja KA, Wang J, Sevier CS. An unexpected role for the yeast nucleotide exchange factor Sil1 as a reductant acting on the molecular chaperone BiP. eLife 2017; 6. [PMID: 28257000 PMCID: PMC5358974 DOI: 10.7554/elife.24141] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2016] [Accepted: 03/02/2017] [Indexed: 12/18/2022] Open
Abstract
Unfavorable redox conditions in the endoplasmic reticulum (ER) can decrease the capacity for protein secretion, altering vital cell functions. While systems to manage reductive stress are well-established, how cells cope with an overly oxidizing ER remains largely undefined. In previous work (Wang et al., 2014), we demonstrated that the chaperone BiP is a sensor of overly oxidizing ER conditions. We showed that modification of a conserved BiP cysteine during stress beneficially alters BiP chaperone activity to cope with suboptimal folding conditions. How this cysteine is reduced to reestablish 'normal' BiP activity post-oxidative stress has remained unknown. Here we demonstrate that BiP's nucleotide exchange factor - Sil1 - can reverse BiP cysteine oxidation. This previously unexpected reductant capacity for yeast Sil1 has potential implications for the human ataxia Marinesco-Sjögren syndrome, where it is interesting to speculate that a disruption in ER redox-signaling (due to genetic defects in SIL1) may influence disease pathology.
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Affiliation(s)
| | - Kristeen A Pareja
- Department of Molecular Medicine, Cornell University, Ithaca, United States
| | - Jie Wang
- Department of Molecular Medicine, Cornell University, Ithaca, United States
| | - Carolyn S Sevier
- Department of Molecular Medicine, Cornell University, Ithaca, United States
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12
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Osborn DPS, Pond HL, Mazaheri N, Dejardin J, Munn CJ, Mushref K, Cauley ES, Moroni I, Pasanisi MB, Sellars EA, Hill RS, Partlow JN, Willaert RK, Bharj J, Malamiri RA, Galehdari H, Shariati G, Maroofian R, Mora M, Swan LE, Voit T, Conti FJ, Jamshidi Y, Manzini MC. Mutations in INPP5K Cause a Form of Congenital Muscular Dystrophy Overlapping Marinesco-Sjögren Syndrome and Dystroglycanopathy. Am J Hum Genet 2017; 100:537-545. [PMID: 28190459 PMCID: PMC5339112 DOI: 10.1016/j.ajhg.2017.01.019] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2016] [Accepted: 01/05/2017] [Indexed: 02/01/2023] Open
Abstract
Congenital muscular dystrophies display a wide phenotypic and genetic heterogeneity. The combination of clinical, biochemical, and molecular genetic findings must be considered to obtain the precise diagnosis and provide appropriate genetic counselling. Here we report five individuals from four families presenting with variable clinical features including muscular dystrophy with a reduction in dystroglycan glycosylation, short stature, intellectual disability, and cataracts, overlapping both the dystroglycanopathies and Marinesco-Sjögren syndrome. Whole-exome sequencing revealed homozygous missense and compound heterozygous mutations in INPP5K in the affected members of each family. INPP5K encodes the inositol polyphosphate-5-phosphatase K, also known as SKIP (skeletal muscle and kidney enriched inositol phosphatase), which is highly expressed in the brain and muscle. INPP5K localizes to both the endoplasmic reticulum and to actin ruffles in the cytoplasm. It has been shown to regulate myoblast differentiation and has also been implicated in protein processing through its interaction with the ER chaperone HSPA5/BiP. We show that morpholino-mediated inpp5k loss of function in the zebrafish results in shortened body axis, microphthalmia with disorganized lens, microcephaly, reduced touch-evoked motility, and highly disorganized myofibers. Altogether these data demonstrate that mutations in INPP5K cause a congenital muscular dystrophy syndrome with short stature, cataracts, and intellectual disability.
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Affiliation(s)
- Daniel P S Osborn
- Cardiovascular and Cell Sciences Institute, St George's University of London, Cranmer Terrace, London SW17 0RE, UK
| | - Heather L Pond
- Department of Pharmacology and Physiology, The George Washington University School of Medicine and Health Science, Washington, DC 20037, USA
| | - Neda Mazaheri
- Department of Genetics, Shahid Chamran University of Ahvaz, Ahvaz 6135783151, Iran; Narges Medical Genetics and Prenatal Diagnosis Laboratory, East Mihan Ave., Kianpars, Ahvaz 6155689467, Iran
| | - Jeremy Dejardin
- Cardiovascular and Cell Sciences Institute, St George's University of London, Cranmer Terrace, London SW17 0RE, UK
| | - Christopher J Munn
- Department of Cellular and Molecular Physiology, Institute of Translational Medicine, University of Liverpool, Liverpool L69 3BX, UK
| | - Khaloob Mushref
- Department of Pharmacology and Physiology, The George Washington University School of Medicine and Health Science, Washington, DC 20037, USA
| | - Edmund S Cauley
- Department of Pharmacology and Physiology, The George Washington University School of Medicine and Health Science, Washington, DC 20037, USA
| | - Isabella Moroni
- Pediatric Neurology Unit, Fondazione IRCCS Istituto Neurologico C. Besta, 20133 Milan, Italy
| | - Maria Barbara Pasanisi
- Pediatric Neurology Unit, Fondazione IRCCS Istituto Neurologico C. Besta, 20133 Milan, Italy; Division of Neuromuscular Diseases and Neuroimmunology, Fondazione IRCCS Istituto Neurologico C. Besta, 20126 Milan, Italy
| | - Elizabeth A Sellars
- Department of Pediatrics, Section of Genetics and Metabolism, University of Arkansas for Medical Sciences, Arkansas Children's Hospital, Little Rock, AR 72202, USA
| | - R Sean Hill
- Program in Genetics and Genomics, Boston Children's Hospital, Boston, MA 02115, USA; Howard Hughes Medical Institute, Boston Children's Hospital, Boston, MA 02115, USA
| | - Jennifer N Partlow
- Program in Genetics and Genomics, Boston Children's Hospital, Boston, MA 02115, USA; Howard Hughes Medical Institute, Boston Children's Hospital, Boston, MA 02115, USA
| | | | - Jaipreet Bharj
- Cardiovascular and Cell Sciences Institute, St George's University of London, Cranmer Terrace, London SW17 0RE, UK
| | - Reza Azizi Malamiri
- Department of Paediatric Neurology, Golestan Medical, Educational, and Research Center, Ahvaz Jundishapur University of Medical Sciences, Ahvaz 6163764648, Iran
| | - Hamid Galehdari
- Department of Genetics, Shahid Chamran University of Ahvaz, Ahvaz 6135783151, Iran; Narges Medical Genetics and Prenatal Diagnosis Laboratory, East Mihan Ave., Kianpars, Ahvaz 6155689467, Iran
| | - Gholamreza Shariati
- Narges Medical Genetics and Prenatal Diagnosis Laboratory, East Mihan Ave., Kianpars, Ahvaz 6155689467, Iran; Department of Medical Genetics, Faculty of Medicine, Ahvaz Jundishapur, University of Medical Sciences, Ahvaz 6135715794, Iran
| | - Reza Maroofian
- Cardiovascular and Cell Sciences Institute, St George's University of London, Cranmer Terrace, London SW17 0RE, UK; University of Exeter Medical School, RILD Wellcome Wolfson Centre, Royal Devon & Exeter NHS Foundation Trust, Exeter EX1 2LU, UK
| | - Marina Mora
- Division of Neuromuscular Diseases and Neuroimmunology, Fondazione IRCCS Istituto Neurologico C. Besta, 20126 Milan, Italy
| | - Laura E Swan
- Department of Cellular and Molecular Physiology, Institute of Translational Medicine, University of Liverpool, Liverpool L69 3BX, UK
| | - Thomas Voit
- NIHR GOSH Biomedical Research Centre, Great Ormond Street Institute of Child Health, University College London, London WC1N 1EH, UK
| | - Francesco J Conti
- NIHR GOSH Biomedical Research Centre, Great Ormond Street Institute of Child Health, University College London, London WC1N 1EH, UK
| | - Yalda Jamshidi
- Cardiovascular and Cell Sciences Institute, St George's University of London, Cranmer Terrace, London SW17 0RE, UK.
| | - M Chiara Manzini
- Department of Pharmacology and Physiology, The George Washington University School of Medicine and Health Science, Washington, DC 20037, USA.
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13
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Skopkova M, Hennig F, Shin BS, Turner CE, Stanikova D, Brennerova K, Stanik J, Fischer U, Henden L, Müller U, Steinberger D, Leshinsky-Silver E, Bottani A, Kurdiova T, Ukropec J, Nyitrayova O, Kolnikova M, Klimes I, Borck G, Bahlo M, Haas SA, Kim JR, Lotspeich-Cole LE, Gasperikova D, Dever TE, Kalscheuer VM. EIF2S3 Mutations Associated with Severe X-Linked Intellectual Disability Syndrome MEHMO. Hum Mutat 2017; 38:409-425. [PMID: 28055140 DOI: 10.1002/humu.23170] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2016] [Revised: 12/19/2016] [Accepted: 01/02/2017] [Indexed: 12/15/2022]
Abstract
Impairment of translation initiation and its regulation within the integrated stress response (ISR) and related unfolded-protein response has been identified as a cause of several multisystemic syndromes. Here, we link MEHMO syndrome, whose genetic etiology was unknown, to this group of disorders. MEHMO is a rare X-linked syndrome characterized by profound intellectual disability, epilepsy, hypogonadism and hypogenitalism, microcephaly, and obesity. We have identified a C-terminal frameshift mutation (Ile465Serfs) in the EIF2S3 gene in three families with MEHMO syndrome and a novel maternally inherited missense EIF2S3 variant (c.324T>A; p.Ser108Arg) in another male patient with less severe clinical symptoms. The EIF2S3 gene encodes the γ subunit of eukaryotic translation initiation factor 2 (eIF2), crucial for initiation of protein synthesis and regulation of the ISR. Studies in patient fibroblasts confirm increased ISR activation due to the Ile465Serfs mutation and functional assays in yeast demonstrate that the Ile465Serfs mutation impairs eIF2γ function to a greater extent than tested missense mutations, consistent with the more severe clinical phenotype of the Ile465Serfs male mutation carriers. Thus, we propose that more severe EIF2S3 mutations cause the full MEHMO phenotype, while less deleterious mutations cause a milder form of the syndrome with only a subset of the symptoms.
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Affiliation(s)
- Martina Skopkova
- DIABGENE & Laboratory of Diabetes and Metabolic Disorders, Institute of Experimental Endocrinology, Biomedical Research Center, Slovak Academy of Sciences, Bratislava, Slovakia
| | - Friederike Hennig
- Research Group Development and Disease, Max Planck Institute for Molecular Genetics, Berlin, Germany
| | - Byung-Sik Shin
- Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland, USA
| | - Clesson E Turner
- Department of Genetics, Walter Reed National Military Medical Center, Bethesda, Maryland, USA
| | - Daniela Stanikova
- DIABGENE & Laboratory of Diabetes and Metabolic Disorders, Institute of Experimental Endocrinology, Biomedical Research Center, Slovak Academy of Sciences, Bratislava, Slovakia.,First Department of Pediatrics, Medical Faculty of Comenius University, Bratislava, Slovakia
| | - Katarina Brennerova
- First Department of Pediatrics, Medical Faculty of Comenius University, Bratislava, Slovakia
| | - Juraj Stanik
- DIABGENE & Laboratory of Diabetes and Metabolic Disorders, Institute of Experimental Endocrinology, Biomedical Research Center, Slovak Academy of Sciences, Bratislava, Slovakia.,First Department of Pediatrics, Medical Faculty of Comenius University, Bratislava, Slovakia.,Center for Pediatric Research Leipzig, Hospital for Children & Adolescents, University of Leipzig, Germany
| | - Ute Fischer
- Research Group Development and Disease, Max Planck Institute for Molecular Genetics, Berlin, Germany
| | - Lyndal Henden
- Population Health and Immunity Division, The Walter and Eliza Hall Institute of Medical Research, Melbourne, VIC, Australia.,Department of Medical Biology, University of Melbourne, Melbourne, VIC, Australia
| | - Ulrich Müller
- Institut für Humangenetik, Justus-Liebig-Universität Giessen, Giessen, Germany
| | - Daniela Steinberger
- Institut für Humangenetik, Justus-Liebig-Universität Giessen, Giessen, Germany.,bio.logis Center for Human Genetics, Frankfurt a. M., Germany
| | - Esther Leshinsky-Silver
- Institute of Medical Genetics, Wolfson Medical Center, Holon, Israel.,Metabolic-Neurogenetic Clinic, Wolfson Medical Center, Holon, Israel.,Molecular Genetics Laboratory, Wolfson Medical Center, Holon, Israel
| | - Armand Bottani
- Service of Genetic Medicine, Geneva University Hospitals, Geneva, Switzerland
| | - Timea Kurdiova
- DIABGENE & Laboratory of Diabetes and Metabolic Disorders, Institute of Experimental Endocrinology, Biomedical Research Center, Slovak Academy of Sciences, Bratislava, Slovakia
| | - Jozef Ukropec
- DIABGENE & Laboratory of Diabetes and Metabolic Disorders, Institute of Experimental Endocrinology, Biomedical Research Center, Slovak Academy of Sciences, Bratislava, Slovakia
| | | | - Miriam Kolnikova
- Department of Pediatric Neurology, Medical Faculty of Comenius University, Bratislava, Slovakia
| | - Iwar Klimes
- DIABGENE & Laboratory of Diabetes and Metabolic Disorders, Institute of Experimental Endocrinology, Biomedical Research Center, Slovak Academy of Sciences, Bratislava, Slovakia
| | - Guntram Borck
- Institute of Human Genetics, University of Ulm, Ulm, Germany
| | - Melanie Bahlo
- Population Health and Immunity Division, The Walter and Eliza Hall Institute of Medical Research, Melbourne, VIC, Australia.,Department of Medical Biology, University of Melbourne, Melbourne, VIC, Australia
| | - Stefan A Haas
- Department of Computational Molecular Biology, Max Planck Institute for Molecular Genetics, Berlin, Germany
| | - Joo-Ran Kim
- Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland, USA
| | - Leda E Lotspeich-Cole
- Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland, USA
| | - Daniela Gasperikova
- DIABGENE & Laboratory of Diabetes and Metabolic Disorders, Institute of Experimental Endocrinology, Biomedical Research Center, Slovak Academy of Sciences, Bratislava, Slovakia
| | - Thomas E Dever
- Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland, USA
| | - Vera M Kalscheuer
- Research Group Development and Disease, Max Planck Institute for Molecular Genetics, Berlin, Germany
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14
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Nair P, Hamzeh AR, Mohamed M, Tawfiq N, Al-Ali MT, Bastaki F. Marinesco-Sjögren Syndrome in an Emirati Child with a Novel Mutation in SIL1 Affecting the 5' Untranslated Region. Med Princ Pract 2016; 25:580-582. [PMID: 27544240 PMCID: PMC5588509 DOI: 10.1159/000449225] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/08/2016] [Accepted: 08/18/2016] [Indexed: 01/11/2023] Open
Abstract
OBJECTIVE The aim of this study was to report clinical and molecular findings in an Emirati child with Marinesco-Sjögren syndrome born to consanguineous parents. CLINICAL PRESENTATION AND INTERVENTION The child presented with developmental delay, ataxia, bilateral cataracts, and dysmorphic craniofacial features, along with cerebellar atrophy. Sequencing of the SIL1 gene revealed a novel homozygous large indel mutation that was predicted to abrogate part of the 5' untranslated region (UTR) and the first 30 amino acids of the protein. CONCLUSION This was a case of mutation in SIL1 that affected the 5' UTR, translation initiation site and the endoplasmic reticulum-targeting signal sequence. Further studies will be needed on the functional delineation of the mutation.
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Affiliation(s)
- Pratibha Nair
- Centre for Arab Genomic Studies, Dubai Health Authority, Dubai, UAE
- *Pratibha Nair, Centre for Arab Genomic Studies, PO Box 22252, Dubai (UAE), E-Mail
| | | | - Madiha Mohamed
- Department of Pediatrics, Latifa Hospital, Dubai Health Authority, Dubai, UAE
| | - Nafisa Tawfiq
- Department of Pediatrics, Latifa Hospital, Dubai Health Authority, Dubai, UAE
| | | | - Fatma Bastaki
- Department of Pediatrics, Latifa Hospital, Dubai Health Authority, Dubai, UAE
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15
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Duncan EJ, Cheetham ME, Chapple JP, van der Spuy J. The role of HSP70 and its co-chaperones in protein misfolding, aggregation and disease. Subcell Biochem 2015; 78:243-73. [PMID: 25487025 DOI: 10.1007/978-3-319-11731-7_12] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Molecular chaperones and their associated co-chaperones are essential in health and disease as they are key facilitators of protein folding, quality control and function. In particular, the HSP70 molecular chaperone networks have been associated with neurodegenerative diseases caused by aberrant protein folding. The pathogenesis of these disorders usually includes the formation of deposits of misfolded, aggregated protein. HSP70 and its co-chaperones have been recognised as potent modulators of inclusion formation and cell survival in cellular and animal models of neurodegenerative disease. In has become evident that the HSP70 chaperone machine functions not only in folding, but also in proteasome mediated degradation of neurodegenerative disease proteins. Thus, there has been a great deal of interest in the potential manipulation of molecular chaperones as a therapeutic approach for many neurodegenerations. Furthermore, mutations in several HSP70 co-chaperones and putative co-chaperones have been identified as causing inherited neurodegenerative and cardiac disorders, directly linking the HSP70 chaperone system to human disease.
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Affiliation(s)
- Emma J Duncan
- Molecular Endocrinology Centre, William Harvey Research Institute, Barts and the London School of Medicine and Dentistry, Queen Mary University of London, Charter House Square, EC1M 6BQ, London, UK,
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16
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Cerami C, Tarantino P, Cupidi C, Annesi G, Lo Re V, Gagliardi M, Piccoli T, Quattrone A. Marinesco-Sjögren syndrome caused by a new SIL1 frameshift mutation. J Neurol Sci 2015; 354:112-3. [PMID: 25982182 DOI: 10.1016/j.jns.2015.04.026] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2015] [Revised: 04/17/2015] [Accepted: 04/18/2015] [Indexed: 11/29/2022]
Affiliation(s)
- Chiara Cerami
- Department of Experimental Biomedicine and Clinical Neurosciences (BioNeC), University of Palermo, Palermo, Italy.
| | - Patrizia Tarantino
- Institute of Molecular Bioimaging and Physiology, National Research Council, Section of Germaneto, Catanzaro, Italy
| | - Chiara Cupidi
- Department of Experimental Biomedicine and Clinical Neurosciences (BioNeC), University of Palermo, Palermo, Italy
| | - Grazia Annesi
- Institute of Molecular Bioimaging and Physiology, National Research Council, Section of Germaneto, Catanzaro, Italy
| | - Vincenzina Lo Re
- Department of Experimental Biomedicine and Clinical Neurosciences (BioNeC), University of Palermo, Palermo, Italy
| | - Monica Gagliardi
- Institute of Molecular Bioimaging and Physiology, National Research Council, Section of Germaneto, Catanzaro, Italy; Institute of Neurology, Department of Medical and Aurgi Sciences, University Magna Graecia, Catanzaro, Italy
| | - Tommaso Piccoli
- Department of Experimental Biomedicine and Clinical Neurosciences (BioNeC), University of Palermo, Palermo, Italy
| | - Aldo Quattrone
- Institute of Molecular Bioimaging and Physiology, National Research Council, Section of Germaneto, Catanzaro, Italy; Institute of Neurology, Department of Medical and Aurgi Sciences, University Magna Graecia, Catanzaro, Italy
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17
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Behnke J, Feige MJ, Hendershot LM. BiP and its nucleotide exchange factors Grp170 and Sil1: mechanisms of action and biological functions. J Mol Biol 2015; 427:1589-608. [PMID: 25698114 DOI: 10.1016/j.jmb.2015.02.011] [Citation(s) in RCA: 135] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2014] [Revised: 02/10/2015] [Accepted: 02/10/2015] [Indexed: 12/26/2022]
Abstract
BiP (immunoglobulin heavy-chain binding protein) is the endoplasmic reticulum (ER) orthologue of the Hsp70 family of molecular chaperones and is intricately involved in most functions of this organelle through its interactions with a variety of substrates and regulatory proteins. Like all Hsp70 family members, the ability of BiP to bind and release unfolded proteins is tightly regulated by a cycle of ATP binding, hydrolysis, and nucleotide exchange. As a characteristic of the Hsp70 family, multiple DnaJ-like co-factors can target substrates to BiP and stimulate its ATPase activity to stabilize the binding of BiP to substrates. However, only in the past decade have nucleotide exchange factors for BiP been identified, which has shed light not only on the mechanism of BiP-assisted folding in the ER but also on Hsp70 family members that reside throughout the cell. We will review the current understanding of the ATPase cycle of BiP in the unique environment of the ER and how it is regulated by the nucleotide exchange factors, Grp170 (glucose-regulated protein of 170kDa) and Sil1, both of which perform unanticipated roles in various biological functions and disease states.
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Affiliation(s)
- Julia Behnke
- Department of Tumor Cell Biology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - Matthias J Feige
- Department of Tumor Cell Biology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - Linda M Hendershot
- Department of Tumor Cell Biology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA.
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18
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Subramony S, Moscovich M, Ashizawa T. Genetics and Clinical Features of Inherited Ataxias. Mov Disord 2015. [DOI: 10.1016/b978-0-12-405195-9.00062-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
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19
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Ichhaporia VP, Sanford T, Howes J, Marion TN, Hendershot LM. Sil1, a nucleotide exchange factor for BiP, is not required for antibody assembly or secretion. Mol Biol Cell 2014; 26:420-9. [PMID: 25473114 PMCID: PMC4310734 DOI: 10.1091/mbc.e14-09-1392] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Sil1 is a nucleotide exchange factor for the ER chaperone BiP, and mutations in this gene lead to Marinesco–Sjögren syndrome, a multisystem disorder. Effects of loss of Sil1 on biosynthesis and secretion of antibodies, a well-characterized BiP client, are determined in a mouse model for this disease and patient-derived lymphoblastoid cell lines. Sil1 is a nucleotide exchange factor for the endoplasmic reticulum chaperone BiP, and mutations in this gene lead to Marinesco–Sjögren syndrome (MSS), a debilitating autosomal recessive disease characterized by multisystem defects. A mouse model for MSS was previously produced by disrupting Sil1 using gene-trap methodology. The resulting Sil1Gt mouse phenocopies several pathologies associated with MSS, although its ability to assemble and secrete antibodies, the best-characterized substrate of BiP, has not been investigated. In vivo antigen-specific immunizations and ex vivo LPS stimulation of splenic B cells revealed that the Sil1Gt mouse was indistinguishable from wild-type age-matched controls in terms of both the kinetics and magnitude of antigen-specific antibody responses. There was no significant accumulation of BiP-associated Ig assembly intermediates or evidence that another molecular chaperone system was used for antibody production in the LPS-stimulated splenic B cells from Sil1Gt mice. ER chaperones were expressed at the same level in Sil1WT and Sil1Gt mice, indicating that there was no evident compensation for the disruption of Sil1. Finally, these results were confirmed and extended in three human EBV-transformed lymphoblastoid cell lines from individuals with MSS, leading us to conclude that the BiP cofactor Sil1 is dispensable for antibody production.
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Affiliation(s)
- Viraj P Ichhaporia
- Department of Tumor Cell Biology, St. Jude Children's Research Hospital, Memphis, TN 38105; Department of Microbiology, Immunology, and Biochemistry, University of Tennessee Health Sciences Center, Memphis, TN 38163
| | - Tyler Sanford
- Department of Tumor Cell Biology, St. Jude Children's Research Hospital, Memphis, TN 38105; Department of Microbiology, Immunology, and Biochemistry, University of Tennessee Health Sciences Center, Memphis, TN 38163
| | - Jenny Howes
- Department of Tumor Cell Biology, St. Jude Children's Research Hospital, Memphis, TN 38105
| | - Tony N Marion
- Department of Microbiology, Immunology, and Biochemistry, University of Tennessee Health Sciences Center, Memphis, TN 38163
| | - Linda M Hendershot
- Department of Tumor Cell Biology, St. Jude Children's Research Hospital, Memphis, TN 38105;
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20
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Thomas AC, Williams H, Setó-Salvia N, Bacchelli C, Jenkins D, O'Sullivan M, Mengrelis K, Ishida M, Ocaka L, Chanudet E, James C, Lescai F, Anderson G, Morrogh D, Ryten M, Duncan AJ, Pai YJ, Saraiva JM, Ramos F, Farren B, Saunders D, Vernay B, Gissen P, Straatmaan-Iwanowska A, Baas F, Wood NW, Hersheson J, Houlden H, Hurst J, Scott R, Bitner-Glindzicz M, Moore GE, Sousa SB, Stanier P. Mutations in SNX14 cause a distinctive autosomal-recessive cerebellar ataxia and intellectual disability syndrome. Am J Hum Genet 2014; 95:611-21. [PMID: 25439728 DOI: 10.1016/j.ajhg.2014.10.007] [Citation(s) in RCA: 73] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2014] [Accepted: 10/13/2014] [Indexed: 12/30/2022] Open
Abstract
Intellectual disability and cerebellar atrophy occur together in a large number of genetic conditions and are frequently associated with microcephaly and/or epilepsy. Here we report the identification of causal mutations in Sorting Nexin 14 (SNX14) found in seven affected individuals from three unrelated consanguineous families who presented with recessively inherited moderate-severe intellectual disability, cerebellar ataxia, early-onset cerebellar atrophy, sensorineural hearing loss, and the distinctive association of progressively coarsening facial features, relative macrocephaly, and the absence of seizures. We used homozygosity mapping and whole-exome sequencing to identify a homozygous nonsense mutation and an in-frame multiexon deletion in two families. A homozygous splice site mutation was identified by Sanger sequencing of SNX14 in a third family, selected purely by phenotypic similarity. This discovery confirms that these characteristic features represent a distinct and recognizable syndrome. SNX14 encodes a cellular protein containing Phox (PX) and regulator of G protein signaling (RGS) domains. Weighted gene coexpression network analysis predicts that SNX14 is highly coexpressed with genes involved in cellular protein metabolism and vesicle-mediated transport. All three mutations either directly affected the PX domain or diminished SNX14 levels, implicating a loss of normal cellular function. This manifested as increased cytoplasmic vacuolation as observed in cultured fibroblasts. Our findings indicate an essential role for SNX14 in neural development and function, particularly in development and maturation of the cerebellum.
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Affiliation(s)
- Anna C Thomas
- Genetics and Genomic Medicine, UCL Institute of Child Health, London WC1N 1EH, UK
| | - Hywel Williams
- Genetics and Genomic Medicine, UCL Institute of Child Health, London WC1N 1EH, UK; Centre for Translational Omics-GOSgene, UCL Institute of Child Health, London WC1N 1EH, UK
| | - Núria Setó-Salvia
- Genetics and Genomic Medicine, UCL Institute of Child Health, London WC1N 1EH, UK
| | - Chiara Bacchelli
- Genetics and Genomic Medicine, UCL Institute of Child Health, London WC1N 1EH, UK; Centre for Translational Omics-GOSgene, UCL Institute of Child Health, London WC1N 1EH, UK
| | - Dagan Jenkins
- Genetics and Genomic Medicine, UCL Institute of Child Health, London WC1N 1EH, UK
| | - Mary O'Sullivan
- Genetics and Genomic Medicine, UCL Institute of Child Health, London WC1N 1EH, UK
| | | | - Miho Ishida
- Genetics and Genomic Medicine, UCL Institute of Child Health, London WC1N 1EH, UK
| | - Louise Ocaka
- Genetics and Genomic Medicine, UCL Institute of Child Health, London WC1N 1EH, UK; Centre for Translational Omics-GOSgene, UCL Institute of Child Health, London WC1N 1EH, UK
| | - Estelle Chanudet
- Genetics and Genomic Medicine, UCL Institute of Child Health, London WC1N 1EH, UK; Centre for Translational Omics-GOSgene, UCL Institute of Child Health, London WC1N 1EH, UK
| | - Chela James
- Genetics and Genomic Medicine, UCL Institute of Child Health, London WC1N 1EH, UK; Centre for Translational Omics-GOSgene, UCL Institute of Child Health, London WC1N 1EH, UK
| | - Francesco Lescai
- Genetics and Genomic Medicine, UCL Institute of Child Health, London WC1N 1EH, UK; Centre for Translational Omics-GOSgene, UCL Institute of Child Health, London WC1N 1EH, UK; Department of Biomedicine, Aarhus University, 8000 Aarhus, Denmark
| | - Glenn Anderson
- Histopathology Department, Great Ormond Street Hospital, London WC1N 3JH, UK
| | - Deborah Morrogh
- NE Thames Regional Genetics Laboratory Service, London WC1N 3BH, UK
| | - Mina Ryten
- UCL Institute of Neurology, London WC1N 3BG, UK; Department of Clinical Genetics, Guy's Hospital, London SE1 9RT, UK
| | - Andrew J Duncan
- Genetics and Genomic Medicine, UCL Institute of Child Health, London WC1N 1EH, UK
| | - Yun Jin Pai
- Developmental Biology and Cancer, UCL Institute of Child Health, London WC1N 1EH, UK
| | - Jorge M Saraiva
- Serviço de Genética Médica, Hospital Pediátrico, Centro Hospitalar e Universitário de Coimbra, 3000-602 Coimbra, Portugal; University Clinic of Pediatrics, Faculty of Medicine, University of Coimbra, 3000-602 Coimbra, Portugal
| | - Fabiana Ramos
- Serviço de Genética Médica, Hospital Pediátrico, Centro Hospitalar e Universitário de Coimbra, 3000-602 Coimbra, Portugal
| | - Bernadette Farren
- Clinical Genetics, Great Ormond Street Hospital, London WC1N 3JH, UK
| | - Dawn Saunders
- Radiology, Great Ormond Street Hospital, London WC1N 3JH, UK
| | - Bertrand Vernay
- Developmental Biology and Cancer, UCL Institute of Child Health, London WC1N 1EH, UK
| | - Paul Gissen
- Genetics and Genomic Medicine, UCL Institute of Child Health, London WC1N 1EH, UK
| | | | - Frank Baas
- Department of Genome Analysis, Academic Medical Center, University of Amsterdam, 1105AZ Amsterdam, the Netherlands
| | | | | | | | - Jane Hurst
- Clinical Genetics, Great Ormond Street Hospital, London WC1N 3JH, UK
| | - Richard Scott
- Clinical Genetics, Great Ormond Street Hospital, London WC1N 3JH, UK
| | - Maria Bitner-Glindzicz
- Genetics and Genomic Medicine, UCL Institute of Child Health, London WC1N 1EH, UK; Clinical Genetics, Great Ormond Street Hospital, London WC1N 3JH, UK
| | - Gudrun E Moore
- Genetics and Genomic Medicine, UCL Institute of Child Health, London WC1N 1EH, UK
| | - Sérgio B Sousa
- Genetics and Genomic Medicine, UCL Institute of Child Health, London WC1N 1EH, UK; Serviço de Genética Médica, Hospital Pediátrico, Centro Hospitalar e Universitário de Coimbra, 3000-602 Coimbra, Portugal.
| | - Philip Stanier
- Genetics and Genomic Medicine, UCL Institute of Child Health, London WC1N 1EH, UK.
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