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Kors S, Costello JL, Schrader M. VAP Proteins - From Organelle Tethers to Pathogenic Host Interactors and Their Role in Neuronal Disease. Front Cell Dev Biol 2022; 10:895856. [PMID: 35756994 PMCID: PMC9213790 DOI: 10.3389/fcell.2022.895856] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2022] [Accepted: 04/25/2022] [Indexed: 12/26/2022] Open
Abstract
Vesicle-associated membrane protein (VAMP)-associated proteins (VAPs) are ubiquitous ER-resident tail-anchored membrane proteins in eukaryotic cells. Their N-terminal major sperm protein (MSP) domain faces the cytosol and allows them to interact with a wide variety of cellular proteins. Therefore, VAP proteins are vital to many cellular processes, including organelle membrane tethering, lipid transfer, autophagy, ion homeostasis and viral defence. Here, we provide a timely overview of the increasing number of VAPA/B binding partners and discuss the role of VAPA/B in maintaining organelle-ER interactions and cooperation. Furthermore, we address how viruses and intracellular bacteria hijack VAPs and their binding partners to induce interactions between the host ER and pathogen-containing compartments and support pathogen replication. Finally, we focus on the role of VAP in human disease and discuss how mutated VAPB leads to the disruption of cellular homeostasis and causes amyotrophic lateral sclerosis.
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Affiliation(s)
- Suzan Kors
- *Correspondence: Suzan Kors, ; Michael Schrader,
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Kamemura K, Chen CA, Okumura M, Miura M, Chihara T. Amyotrophic lateral sclerosis-associated Vap33 is required for maintaining neuronal dendrite morphology and organelle distribution in Drosophila. Genes Cells 2021; 26:230-239. [PMID: 33548103 DOI: 10.1111/gtc.12835] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2020] [Revised: 01/23/2021] [Accepted: 02/03/2021] [Indexed: 12/19/2022]
Abstract
VAMP-associated protein (VAP) is an endoplasmic reticulum (ER) membrane protein that functions as a tethering protein at the membrane contact sites between the ER and various intracellular organelles. Mutations such as P56S in human VAPB cause neurodegenerative diseases such as amyotrophic lateral sclerosis (ALS). However, VAP functions in neurons are poorly understood. Here, we utilized Drosophila olfactory projection neurons with a mosaic analysis with a repressible cell marker (MARCM) to analyze the neuronal function of Vap33, a Drosophila ortholog of human VAPB. In vap33 null mutant clones, the dendrites of projection neurons exhibited defects in the maintenance of their morphology. The subcellular localization of the Golgi apparatus and mitochondria were also abnormal. These results indicate that Vap33 is required for neuronal morphology and organelle distribution. Additionally, to examine the impact of ALS-associated mutations in neurons, we overexpressed human VAPB-P56S in vap33 null mutant clones (mosaic rescue experiments) and found that, in aged flies, human VAPB-P56S expression caused mislocalization of Bruchpilot, a presynaptic protein. These results implied that synaptic protein localization and ER quality control may be affected by disease mutations. We provide insights into the physiological and pathological functions of VAP in neurons.
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Affiliation(s)
- Kosuke Kamemura
- Program of Biomedical Science and Basic Biology, Graduate School of Integrated Sciences for Life, Hiroshima University, Hiroshima, Japan
| | - Chun-An Chen
- Department of Genetics, Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo, Japan
| | - Misako Okumura
- Program of Biomedical Science and Basic Biology, Graduate School of Integrated Sciences for Life, Hiroshima University, Hiroshima, Japan
| | - Masayuki Miura
- Department of Genetics, Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo, Japan
| | - Takahiro Chihara
- Program of Biomedical Science and Basic Biology, Graduate School of Integrated Sciences for Life, Hiroshima University, Hiroshima, Japan
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3
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Kamemura K, Chihara T. Multiple functions of the ER-resident VAP and its extracellular role in neural development and disease. J Biochem 2019; 165:391-400. [PMID: 30726905 DOI: 10.1093/jb/mvz011] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2018] [Accepted: 02/05/2019] [Indexed: 12/14/2022] Open
Abstract
VAP (VAMP-associated protein) is a type II integral membrane protein of the endoplasmic reticulum (ER), and its N-terminal major sperm protein (MSP) domain faces the cytoplasmic side. VAP functions as a tethering molecule at the membrane contact sites between the ER and intracellular organelles and regulates a wide variety of cellular functions, including lipid transport, membrane trafficking, microtubule reorganization and unfolded protein response. VAP-point mutations in human vapb are strongly associated with amyotrophic lateral sclerosis. Importantly, the MSP domain of VAP is cleaved, secreted and interacts with the axon growth cone guidance receptors (Eph, Robo, Lar), suggesting that VAP could function as a circulating hormone similar to the Caenorhabditis elegans MSP protein. In this review, we discuss not only the intracellular functions of VAP but also the recently discovered extracellular functions and their implications for neurodegenerative disease.
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Affiliation(s)
- Kosuke Kamemura
- Department of Biological Science, Graduate School of Science, Hiroshima University, Hiroshima, Japan
| | - Takahiro Chihara
- Department of Biological Science, Graduate School of Science, Hiroshima University, Hiroshima, Japan
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Sun YM, Dong Y, Wang J, Lu JH, Chen Y, Wu JJ. A novel mutation of VAPB in one Chinese familial amyotrophic lateral sclerosis pedigree and its clinical characteristics. J Neurol 2017; 264:2387-2393. [PMID: 28993872 DOI: 10.1007/s00415-017-8628-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2017] [Revised: 09/20/2017] [Accepted: 09/21/2017] [Indexed: 12/13/2022]
Abstract
The mutation of vesicle-associated membrane protein-associated protein B (VAPB) was proved to cause family amyotrophic lateral sclerosis (FALS). Only two mutations of VAPB associated with ALS have been reported (p.Pro56Ser and p.Thr46Ile). Here we reported a Chinese Han FALS family caused by a novel VAPB point mutation. The clinical materials of one Chinese Han FALS family were collected. The genetic analysis was carried out by target sequencing and further verified by Sanger sequencing. One novel mutation of c.167C>A (p.Pro56His) on VAPB was found in the proband. The age at onset of the proband was 48 with the onset symptoms of weakness in the right arm, followed by progressive limb and trunk weakness with decreased deep-tendon reflexes, muscular cramps and fasciculation. But the disease duration was more than 15 years. He was under the tracheotomy for 1 year at last visit. Electromyography showed widespread acute and chronic neurogenic damages. His mother presented weakness in her limbs in 50 s and died 15 years later. One of his younger sisters diagnosed as ALS for 6 years also carried the same mutation. She presented the similar symptoms on 41. No dominant upper motor neuron sign was showed. The clinical features were similar to the patients carrying the known mutation of p.Pro56Ser. A novel mutation of VAPB was found in one Chinese Han FALS pedigree. The affected patients presented a much slower progression and the lesions were limited in lower motor neurons.
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Affiliation(s)
- Yi-Min Sun
- Department of Neurology, National Clinical Research Center for Aging and Medicine, Huashan Hospital, Fudan University, 12 Wulumuqi Zhong Road, Shanghai, 200040, China
| | - Yi Dong
- Department of Neurology, National Clinical Research Center for Aging and Medicine, Huashan Hospital, Fudan University, 12 Wulumuqi Zhong Road, Shanghai, 200040, China
| | - Jian Wang
- Department of Neurology, National Clinical Research Center for Aging and Medicine, Huashan Hospital, Fudan University, 12 Wulumuqi Zhong Road, Shanghai, 200040, China
| | - Jia-Hong Lu
- Department of Neurology, National Clinical Research Center for Aging and Medicine, Huashan Hospital, Fudan University, 12 Wulumuqi Zhong Road, Shanghai, 200040, China
| | - Yan Chen
- Department of Neurology, National Clinical Research Center for Aging and Medicine, Huashan Hospital, Fudan University, 12 Wulumuqi Zhong Road, Shanghai, 200040, China.
| | - Jian-Jun Wu
- Department of Neurology, National Clinical Research Center for Aging and Medicine, Huashan Hospital, Fudan University, 12 Wulumuqi Zhong Road, Shanghai, 200040, China.
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5
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Kun-Rodrigues C, Ganos C, Guerreiro R, Schneider SA, Schulte C, Lesage S, Darwent L, Holmans P, Singleton A, Bhatia K, Bras J. A systematic screening to identify de novo mutations causing sporadic early-onset Parkinson's disease. Hum Mol Genet 2015; 24:6711-20. [PMID: 26362251 PMCID: PMC4634375 DOI: 10.1093/hmg/ddv376] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2015] [Accepted: 09/08/2015] [Indexed: 12/13/2022] Open
Abstract
Despite the many advances in our understanding of the genetic basis of Mendelian forms of Parkinson's disease (PD), a large number of early-onset cases still remain to be explained. Many of these cases, present with a form of disease that is identical to that underlined by genetic causes, but do not have mutations in any of the currently known disease-causing genes. Here, we hypothesized that de novo mutations may account for a proportion of these early-onset, sporadic cases. We performed exome sequencing in full parent–child trios where the proband presents with typical PD to unequivocally identify de novo mutations. This approach allows us to test all genes in the genome in an unbiased manner. We have identified and confirmed 20 coding de novo mutations in 21 trios. We have used publicly available population genetic data to compare variant frequencies and our independent in-house dataset of exome sequencing in PD (with over 1200 cases) to identify additional variants in the same genes. Of the genes identified to carry de novo mutations, PTEN, VAPB and ASNA1 are supported by various sources of data to be involved in PD. We show that these genes are reported to be within a protein–protein interaction network with PD genes and that they contain additional rare, case-specific, mutations in our independent cohort of PD cases. Our results support the involvement of these three genes in PD and suggest that testing for de novo mutations in sporadic disease may aid in the identification of novel disease-causing genes.
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Affiliation(s)
- Celia Kun-Rodrigues
- Department of Molecular Neuroscience, UCL Institute of Neurology, London WC1N 3AR, UK
| | - Christos Ganos
- Department of Neurology, University Medical Center Hamburg-Eppendorf (UKE), Hamburg 20246, Germany, Sobell Department of Motor Neuroscience and Movement Disorders, UCL Institute of Neurology, University College London, London WC1N 3BG, UK
| | - Rita Guerreiro
- Department of Molecular Neuroscience, UCL Institute of Neurology, London WC1N 3AR, UK
| | - Susanne A Schneider
- Department of Neurology, University Hospital Schleswig Holstein, Campus Kiel 24105, Germany
| | - Claudia Schulte
- German Center for Neurodegenerative Diseases, Tübingen, Germany, Department of Neurodegenerative Diseases, Hertie Institute for Clinical Brain Research, University of Tübingen, Tübingen 72076, Germany
| | - Suzanne Lesage
- INSERM U M27, Pitié-Salpêtrière Hospital, Brain and Spinal Cord Institute (ICM), Paris 75013, France
| | - Lee Darwent
- Department of Molecular Neuroscience, UCL Institute of Neurology, London WC1N 3AR, UK
| | - Peter Holmans
- Medical Research Council Centre for Neuropsychiatric Genetics and Genomics, Institute of Psychological Medicine and Clinical Neurosciences, Cardiff University, Cardiff CF24 4HQ, UK and
| | - Andrew Singleton
- Laboratory of Neurogenetics, National Institutes on Aging, National Institutes of Health, Bethesda, MD 20892, USA
| | - Kailash Bhatia
- Sobell Department of Motor Neuroscience and Movement Disorders, UCL Institute of Neurology, University College London, London WC1N 3BG, UK
| | - Jose Bras
- Department of Molecular Neuroscience, UCL Institute of Neurology, London WC1N 3AR, UK,
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Abstract
Our understanding of amyotrophic lateral sclerosis (ALS), a fatal neurodegenerative disease, is expanding rapidly as its genetic causes are uncovered. The pace of new gene discovery over the last 5 years has accelerated, providing new insights into the pathogenesis of disease and highlighting biological pathways as targets for therapeutic development. This article reviews our current understanding of the heritability of ALS and provides an overview of each of the major ALS genes, highlighting their phenotypic characteristics and frequencies as a guide for clinicians evaluating patients with ALS.
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Affiliation(s)
- Matthew B Harms
- Neuromuscular Division, Department of Neurology, Hope Center for Neurological Disorders, Washington University School of Medicine, 660 South Euclid Avenue, St Louis, MO 63110, USA.
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Ingre C, Pinto S, Birve A, Press R, Danielsson O, de Carvalho M, Guđmundsson G, Andersen PM. No association between VAPB mutations and familial or sporadic ALS in Sweden, Portugal and Iceland. Amyotroph Lateral Scler Frontotemporal Degener 2013; 14:620-7. [PMID: 23971766 DOI: 10.3109/21678421.2013.822515] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Linkage analysis in Brazilian families with amyotrophic lateral sclerosis (ALS) revealed that a missense mutation p.Pro56Ser in a conserved gene VAMP-associated protein type B and C (VAPB) cosegregates with disease. Blood samples were studied from 973 Swedish, 126 Portuguese and 19 Icelandic ALS patients, and from 644 control subjects. We identified five VAPB mutations, two of which are novel, in 14 Swedish ALS patients and in nine control individuals from Sweden and Portugal. The 14 patients with VAPB mutations all carried a diagnosis of sporadic ALS. Mutations were also found in healthy adult relatives. The p.Asp130Glu VAPB mutation was also found in two patients from an Icelandic ALS family, but the mutation did not cosegregate with disease. All patients were instead found to be heterozygous for a p.Gly93Ser SOD1 mutation. There were no clinical differences between them, suggesting that the p.Asp130Glu VAPB mutation is unrelated to the disease process. In conclusion, the VAPB mutations were as frequent in control individuals as in patients. This observation, in combination with the finding of several healthy relatives carrying the VAPB mutations and no ancestors with ALS disease, suggests that it is unlikely that these VAPB mutations are pathogenic.
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Affiliation(s)
- Caroline Ingre
- Department of Pharmacology and Clinical Neuroscience, Umeå University , Umeå
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VAPB and C9orf72 mutations in 1 familial amyotrophic lateral sclerosis patient. Neurobiol Aging 2012; 33:2950.e1-4. [DOI: 10.1016/j.neurobiolaging.2012.07.004] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2012] [Accepted: 07/10/2012] [Indexed: 12/11/2022]
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Cozzolino M, Pesaresi MG, Gerbino V, Grosskreutz J, Carrì MT. Amyotrophic lateral sclerosis: new insights into underlying molecular mechanisms and opportunities for therapeutic intervention. Antioxid Redox Signal 2012; 17:1277-330. [PMID: 22413952 DOI: 10.1089/ars.2011.4328] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Recent years have witnessed a renewed interest in the pathogenic mechanisms of amyotrophic lateral sclerosis (ALS), a late-onset progressive degeneration of motor neurons. The discovery of new genes associated with the familial form of the disease, along with a deeper insight into pathways already described for this disease, has led scientists to reconsider previous postulates. While protein misfolding, mitochondrial dysfunction, oxidative damage, defective axonal transport, and excitotoxicity have not been dismissed, they need to be re-examined as contributors to the onset or progression of ALS in the light of the current knowledge that the mutations of proteins involved in RNA processing, apparently unrelated to the previous "old partners," are causative of the same phenotype. Thus, newly envisaged models and tools may offer unforeseen clues on the etiology of this disease and hopefully provide the key to treatment.
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Chen HJ, Anagnostou G, Chai A, Withers J, Morris A, Adhikaree J, Pennetta G, de Belleroche JS. Characterization of the properties of a novel mutation in VAPB in familial amyotrophic lateral sclerosis. J Biol Chem 2010; 285:40266-81. [PMID: 20940299 PMCID: PMC3001007 DOI: 10.1074/jbc.m110.161398] [Citation(s) in RCA: 128] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Following the mutation screening of genes known to cause amyotrophic lateral sclerosis (ALS) in index cases from 107 familial ALS (FALS) kindred, a point mutation was identified in vesicle-associated membrane protein-associated protein B (VAPB), or VAMP-associated protein B, causing an amino acid change from threonine to isoleucine at codon 46 (T46I) in one FALS case but not in 257 controls. This is an important finding because it is only the second mutation identified in this gene that causes ALS. In order to investigate the pathogenic effects of this mutation, we have used a motor neuron cell line and tissue-specific expression of the mutant protein in Drosophila. We provide substantial evidence for the pathogenic effects of this mutation in abolishing the effect of wild type VAPB in the unfolded protein response, promoting ubiquitin aggregate formation, and activating neuronal cell death. We also report that expression of the mutant protein in the Drosophila motor system induces aggregate deposition, endoplasmic reticulum disorganization, and chaperone up-regulation both in neurons and in muscles. Our integrated analysis of the pathogenic effect of the T46I mutation and the previously identified P56S mutation indicate extensive commonalities in the disease mechanism for these two mutations. In summary, we show that this newly identified mutation in human FALS has a pathogenic effect, supporting and reinforcing the role of VAPB as a causative gene of ALS.
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Affiliation(s)
- Han-Jou Chen
- Division of Experimental Medicine, Faculty of Medicine, Centre for Neuroscience, Hammersmith Hospital, Imperial College London, London W12 0NN, United Kingdom
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Suzuki H, Kanekura K, Levine TP, Kohno K, Olkkonen VM, Aiso S, Matsuoka M. ALS-linked P56S-VAPB, an aggregated loss-of-function mutant of VAPB, predisposes motor neurons to ER stress-related death by inducing aggregation of co-expressed wild-type VAPB. J Neurochem 2010. [DOI: 10.1111/j.0022-3042.2008.05857.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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Luquin N, Yu B, Trent RJ, Pamphlett R. DHPLC can be used to detect low-level mutations in amyotrophic lateral sclerosis. ACTA ACUST UNITED AC 2010; 11:76-82. [PMID: 20184515 DOI: 10.3109/17482960802572699] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Somatic mutations have been suggested as a cause of sporadic amyotrophic lateral sclerosis (SALS). These mutations can be difficult to detect since they may involve only a small percentage of cells within the tissue, so we devised a method to detect low mutation levels in brain DNA. Different proportions of a known SOD1 mutation were prepared to determine the sensitivity of DHPLC. The fraction containing the mutant signal was collected and re-amplified ('enriched') to increase sensitivity and to dideoxy sequence the mutation. The combined technique was used to screen all exons and the promoter of SOD1 in 23 SALS brains. DHPLC could detect a known SOD1 mutation in 5% of a sample of brain tissue. Using our enrichment technique doubled the height of the mutant sequencing signal, which allowed identification of an unknown mutation in 10% of brain tissue. No SOD1 mutations were found in the SALS brains using this technique. In conclusion, combining DHPLC and sequencing doubles the sensitivity of sequencing alone and can detect low levels of known and unknown mutations in brain DNA. No SALS SOD1 somatic mutations were detected, but DHPLC would be useful in looking for somatic mutations in other SALS candidate genes.
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Affiliation(s)
- Natasha Luquin
- Department of Molecular and Clinical Genetics, Royal Prince Alfred Hospital, Sydney, Australia
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Funke AD, Esser M, Krüttgen A, Weis J, Mitne-Neto M, Lazar M, Nishimura AL, Sperfeld AD, Trillenberg P, Senderek J, Krasnianski M, Zatz M, Zierz S, Deschauer M. The p.P56S mutation in the VAPB gene is not due to a single founder: the first European case. Clin Genet 2010; 77:302-3. [PMID: 20447143 PMCID: PMC2847198 DOI: 10.1111/j.1399-0004.2009.01319.x] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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Ticozzi N, Silani V, LeClerc AL, Keagle P, Gellera C, Ratti A, Taroni F, Kwiatkowski TJ, McKenna-Yasek DM, Sapp PC, Brown RH, Landers JE. Analysis of FUS gene mutation in familial amyotrophic lateral sclerosis within an Italian cohort. Neurology 2009; 73:1180-5. [PMID: 19741215 DOI: 10.1212/wnl.0b013e3181bbff05] [Citation(s) in RCA: 109] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
OBJECTIVE Mutations in the FUS gene on chromosome 16 have been recently discovered as a cause of familial amyotrophic lateral sclerosis (FALS). This study determined the frequency and identities of FUS gene mutations in a cohort of Italian patients with FALS. METHODS We screened all 15 coding exons of FUS for mutations in 94 Italian patients with FALS. RESULTS We identified 4 distinct missense mutations in 5 patients; 2 were novel. The mutations were not present in 376 healthy Italian controls and thus are likely to be pathogenic. CONCLUSIONS Our results demonstrate that FUS mutations cause approximately 4% of familial amyotrophic lateral sclerosis cases in the Italian population.
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Affiliation(s)
- N Ticozzi
- Department of Neurology, University of Massachusetts Medical School, Worcester, Massachusetts, USA
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15
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Suzuki H, Kanekura K, Levine TP, Kohno K, Olkkonen VM, Aiso S, Matsuoka M. ALS-linked P56S-VAPB, an aggregated loss-of-function mutant of VAPB, predisposes motor neurons to ER stress-related death by inducing aggregation of co-expressed wild-type VAPB. J Neurochem 2009; 108:973-985. [PMID: 19183264 DOI: 10.1111/j.1471-4159.2008.05857.x] [Citation(s) in RCA: 101] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
A point mutation (P56S) in the vapb gene encoding an endoplasmic reticulum (ER)-integrated membrane protein [vesicle-associated membrane protein-associated protein B (VAPB)] causes autosomal-dominant amyotrophic lateral sclerosis. In our earlier study, we showed that VAPB may be involved in the IRE1/XBP1 signaling of the unfolded protein response, an ER reaction to inhibit accumulation of unfolded/ misfolded proteins, while P56S-VAPB formed insoluble aggregates and lost the ability to mediate the pathway (lossof- function), and suggested that P56S-VAPB promoted the aggregation of co-expressed wild-type (wt)-VAPB. In this study, a yeast inositol-auxotrophy assay has confirmed that P56S-VAPB is functionally a null mutant in vivo. The interaction between P56S-VAPB and wt-VAPB takes place with a high affinity through the major sperm protein domain in addition to the interaction through the C-terminal transmembrane domain. Consequently, wt-VAPB is speculated to preferentially interact with co-expressed P56S-VAPB, leading to the recruitment of wt-VAPB into cytosolic aggregates and the attenuation of its normal function. We have also found that expression of P56S-VAPB increases the vulnerability of NSC34 motoneuronal cells to ER stress-induced death. These results lead us to hypothesize that the total loss of VAPB function in unfolded protein response, induced by one P56S mutant allele, may contribute to the development of P56SVAPB- induced amyotrophic lateral sclerosis.
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Affiliation(s)
- Hiroaki Suzuki
- Department of Cell Biology and Neuroscience, KEIO University School of Medicine, Tokyo, Japan
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16
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Génétique des maladies du motoneurone. Rev Neurol (Paris) 2008; 164:115-30. [DOI: 10.1016/j.neurol.2007.10.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2007] [Revised: 09/25/2007] [Accepted: 10/21/2007] [Indexed: 02/08/2023]
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17
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Schymick JC, Scholz SW, Fung HC, Britton A, Arepalli S, Gibbs JR, Lombardo F, Matarin M, Kasperaviciute D, Hernandez DG, Crews C, Bruijn L, Rothstein J, Mora G, Restagno G, Chiò A, Singleton A, Hardy J, Traynor BJ. Genome-wide genotyping in amyotrophic lateral sclerosis and neurologically normal controls: first stage analysis and public release of data. Lancet Neurol 2007; 6:322-8. [PMID: 17362836 DOI: 10.1016/s1474-4422(07)70037-6] [Citation(s) in RCA: 176] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
BACKGROUND The cause of sporadic ALS is currently unknown. Despite evidence for a role for genetics, no common genetic variants have been unequivocally linked to sporadic ALS. We sought to identify genetic variants associated with an increased or decreased risk for developing ALS in a cohort of American sporadic cases. METHODS We undertook a genome-wide association study using publicly available samples from 276 patients with sporadic ALS and 271 neurologically normal controls. 555 352 unique SNPs were assayed in each sample using the Illumina Infinium II HumanHap550 SNP chip. FINDINGS More than 300 million genotypes were produced in 547 participants. These raw genotype data are freely available on the internet and represent the first publicly accessible SNP data for ALS cases. 34 SNPs with a p value less than 0.0001 (two degrees of freedom) were found, although none of these reached significance after Bonferroni correction. INTERPRETATION We generated publicly available genotype data for sporadic ALS patients and controls. No single locus was definitively associated with increased risk of developing disease, although potentially associated candidate SNPs were identified.
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Affiliation(s)
- Jennifer C Schymick
- Laboratory of Neurogenetics, National Institute on Aging, National Institute of Mental Health, National Institutes of Health, Bethesda, MD, USA
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