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Yıldırım M, Yarenci GB, Genç MB, Uçar Çİ, Bayav S, Tekin MN, Bektaş Ö, Teber S. VAMP1-Related Congenital Myasthenic Syndrome: A Case Report and Literature Review. Neuropediatrics 2024; 55:200-204. [PMID: 38531369 DOI: 10.1055/s-0044-1782675] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 03/28/2024]
Abstract
Congenital myasthenic syndrome-25 (CMS-25) is an autosomal recessive neuromuscular disorder caused by a homozygous mutation in VAMP1 gene. To date, only eight types of allelic variants in VAMP1 gene have been reported in 12 cases of CMS-25. Here, we report on an 8-year-old boy with motor developmental delay, axial hypotonia, myopathic face, muscle weakness, strabismus, ptosis, pectus carinatum, kyphoscoliosis, joint contractures, joint laxity, seizures, and recurrent nephrolithiasis. He also had feeding difficulties and recurrent aspiration pneumonia. Brain magnetic resonance imaging at 20 months of age showed left focal cerebellar hypoplasia. Genetic analysis revealed a homozygous missense variant of c.202C > T (p.Arg68Ter) in the VAMP1 gene. Treatment with oral pyridostigmine was started, which resulted in mild improvement in muscle strength. Salbutamol syrup was added a few months later, but no significant improvement was observed. This case report presents novel findings such as focal cerebellar hypoplasia and nephrolithiasis in VAMP1-related CMS-25. Consequently, this case report extends the clinical spectrum. Further studies are needed to expand the genotype-phenotype correlations in VAMP1-related CMS-25.
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Affiliation(s)
- Miraç Yıldırım
- Department of Pediatric Neurology, Ankara University Faculty of Medicine, Ankara, Turkey
| | | | | | - Çiğdem İlter Uçar
- Department of Pediatric Neurology, Ankara University Faculty of Medicine, Ankara, Turkey
| | - Secahattin Bayav
- Department of Pediatric Pulmonology, Ankara University Faculty of Medicine, Ankara, Turkey
| | - Merve Nur Tekin
- Department of Pediatric Pulmonology, Ankara University Faculty of Medicine, Ankara, Turkey
| | - Ömer Bektaş
- Department of Pediatric Neurology, Ankara University Faculty of Medicine, Ankara, Turkey
| | - Serap Teber
- Department of Pediatric Neurology, Ankara University Faculty of Medicine, Ankara, Turkey
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Cotrina-Vinagre FJ, Rodríguez-García ME, Del Pozo-Filíu L, Hernández-Laín A, Arteche-López A, Morte B, Sevilla M, Pérez-Jurado LA, Quijada-Fraile P, Camacho A, Martínez-Azorín F. Expanding the genetic and phenotypic spectrum of congenital myasthenic syndrome: new homozygous VAMP1 splicing variants in 2 novel individuals. J Hum Genet 2024; 69:187-196. [PMID: 38355957 DOI: 10.1038/s10038-024-01228-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2023] [Revised: 02/05/2024] [Accepted: 02/05/2024] [Indexed: 02/16/2024]
Abstract
We report the cases of two Spanish pediatric patients with hypotonia, muscle weakness and feeding difficulties at birth. Whole-exome sequencing (WES) uncovered two new homozygous VAMP1 (Vesicle Associated Membrane Protein 1) splicing variants, NM_014231.5:c.129+5 G > A in the boy patient (P1) and c.341-24_341-16delinsAGAAAA in the girl patient (P2). This gene encodes the vesicle-associated membrane protein 1 (VAMP1) that is a component of a protein complex involved in the fusion of synaptic vesicles with the presynaptic membrane. VAMP1 has a highly variable C-terminus generated by alternative splicing that gives rise to three main isoforms (A, B and D), being VAMP1A the only isoform expressed in the nervous system. In order to assess the pathogenicity of these variants, expression experiments of RNA for VAMP1 were carried out. The c.129+5 G > A and c.341-24_341-16delinsAGAAAA variants induced aberrant splicing events resulting in the deletion of exon 2 (r.5_131del; p.Ser2TrpfsTer7) in the three isoforms in the first case, and the retention of the last 14 nucleotides of the 3' of intron 4 (r.340_341ins341-14_341-1; p.Ile114AsnfsTer77) in the VAMP1A isoform in the second case. Pathogenic VAMP1 variants have been associated with autosomal dominant spastic ataxia 1 (SPAX1) and with autosomal recessive presynaptic congenital myasthenic syndrome (CMS). Our patients share the clinical manifestations of CMS patients with two important differences: they do not show the typical electrophysiological pattern that suggests pathology of pre-synaptic neuromuscular junction, and their muscular biopsies present hypertrophic fibers type 1. In conclusion, our data expand both genetic and phenotypic spectrum associated with VAMP1 variants.
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Affiliation(s)
- Francisco Javier Cotrina-Vinagre
- Grupo de Enfermedades Raras, Mitocondriales y Neuromusculares (ERMN). Instituto de Investigación Hospital 12 de Octubre (i+12), Madrid, Spain
| | - María Elena Rodríguez-García
- Grupo de Enfermedades Raras, Mitocondriales y Neuromusculares (ERMN). Instituto de Investigación Hospital 12 de Octubre (i+12), Madrid, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER)-ISCIII, Madrid, Spain
| | - Lucía Del Pozo-Filíu
- Grupo de Enfermedades Raras, Mitocondriales y Neuromusculares (ERMN). Instituto de Investigación Hospital 12 de Octubre (i+12), Madrid, Spain
| | - Aurelio Hernández-Laín
- Servicio de Anatomía Patológica (Neuropatología), Hospital Universitario 12 de Octubre, Madrid, Spain
| | - Ana Arteche-López
- Servicio de Genética, Hospital Universitario 12 de Octubre, E-28041, Madrid, Spain
| | - Beatriz Morte
- Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER)-ISCIII, Madrid, Spain
- Instituto de Investigaciones Biomedicas Alberto Sols (CSIC-UAM), Madrid, Spain
| | - Marta Sevilla
- Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER)-ISCIII, Madrid, Spain
- Department of Medicine and Life Sciences, Universitat Pompeu Fabra, Barcelona, Spain
- Genetics Service, Hospital del Mar, Barcelona, Spain
| | - Luis Alberto Pérez-Jurado
- Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER)-ISCIII, Madrid, Spain
- Department of Medicine and Life Sciences, Universitat Pompeu Fabra, Barcelona, Spain
- Genetics Service, Hospital del Mar, Barcelona, Spain
| | - Pilar Quijada-Fraile
- Unidad Pediátrica de Enfermedades Raras, Enfermedades Mitocondriales y Metabólicas Hereditarias, Hospital 12 de Octubre, Madrid, Spain
| | - Ana Camacho
- Sección de Neurología Infantil, Hospital 12 de Octubre, Universidad Complutense de Madrid, Madrid, Spain
| | - Francisco Martínez-Azorín
- Grupo de Enfermedades Raras, Mitocondriales y Neuromusculares (ERMN). Instituto de Investigación Hospital 12 de Octubre (i+12), Madrid, Spain.
- Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER)-ISCIII, Madrid, Spain.
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Aoyagi K. [Functional roles of VAMP family proteins in pancreatic β-cells]. Seikagaku 2017; 89:247-250. [PMID: 29624990] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
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Salpietro V, Lin W, Vedove AD, Storbeck M, Liu Y, Efthymiou S, Manole A, Wiethoff S, Ye Q, Saggar A, McElreavey K, Krishnakumar SS, Pitt M, Bello OD, Rothman JE, Basel‐Vanagaite L, Hubshman MW, Aharoni S, Manzur AY, Wirth B, Houlden H. Homozygous mutations in VAMP1 cause a presynaptic congenital myasthenic syndrome. Ann Neurol 2017; 81:597-603. [PMID: 28253535 PMCID: PMC5413866 DOI: 10.1002/ana.24905] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2016] [Revised: 02/24/2017] [Accepted: 02/24/2017] [Indexed: 11/07/2022]
Abstract
We report 2 families with undiagnosed recessive presynaptic congenital myasthenic syndrome (CMS). Whole exome or genome sequencing identified segregating homozygous variants in VAMP1: c.51_64delAGGTGGGGGTCCCC in a Kuwaiti family and c.146G>C in an Israeli family. VAMP1 is crucial for vesicle fusion at presynaptic neuromuscular junction (NMJ). Electrodiagnostic examination showed severely low compound muscle action potentials and presynaptic impairment. We assessed the effect of the nonsense mutation on mRNA levels and evaluated the NMJ transmission in VAMP1lew/lew mice, observing neurophysiological features of presynaptic impairment, similar to the patients. Taken together, our findings highlight VAMP1 homozygous mutations as a cause of presynaptic CMS. Ann Neurol 2017;81:597–603
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Affiliation(s)
- Vincenzo Salpietro
- Department of Molecular Neuroscience, Institute of NeurologyUniversity College London Institute of NeurologyLondonUnited Kingdom
| | - Weichun Lin
- Department of NeuroscienceUniversity of Texas Southwestern Medical CenterDallasTX
| | - Andrea Delle Vedove
- Institute of Human Genetics, Center for Molecular Medicine CologneCologneGermany
- Institute for GeneticsUniversity of CologneCologneGermany
| | - Markus Storbeck
- Institute of Human Genetics, Center for Molecular Medicine CologneCologneGermany
- Institute for GeneticsUniversity of CologneCologneGermany
| | - Yun Liu
- Department of NeuroscienceUniversity of Texas Southwestern Medical CenterDallasTX
| | - Stephanie Efthymiou
- Department of Molecular Neuroscience, Institute of NeurologyUniversity College London Institute of NeurologyLondonUnited Kingdom
| | - Andreea Manole
- Department of Molecular Neuroscience, Institute of NeurologyUniversity College London Institute of NeurologyLondonUnited Kingdom
| | - Sarah Wiethoff
- Department of Molecular Neuroscience, Institute of NeurologyUniversity College London Institute of NeurologyLondonUnited Kingdom
| | - Qiaohong Ye
- Department of NeuroscienceUniversity of Texas Southwestern Medical CenterDallasTX
| | - Anand Saggar
- St George's Hospital, National Health Service Foundation TrustLondonUnited Kingdom
| | | | - Shyam S. Krishnakumar
- Department of Cell BiologyYale School of MedicineNew HavenCT
- Department of Clinical and Experimental EpilepsyUniversity College London Institute of NeurologyLondonUnited Kingdom
| | | | - Matthew Pitt
- Department of Clinical NeurophysiologyGreat Ormond Street Hospital for Children, National Health Service Foundation TrustLondonUnited Kingdom
| | - Oscar D. Bello
- Department of Cell BiologyYale School of MedicineNew HavenCT
- Department of Clinical and Experimental EpilepsyUniversity College London Institute of NeurologyLondonUnited Kingdom
| | - James E. Rothman
- Department of Cell BiologyYale School of MedicineNew HavenCT
- Department of Clinical and Experimental EpilepsyUniversity College London Institute of NeurologyLondonUnited Kingdom
| | - Lina Basel‐Vanagaite
- Pediatric Genetics Unit, Schneider Children's Medical Center of IsraelPetach TikvaIsrael
- Raphael Recanati Genetic Institute, Rabin Medical CenterPetach TikvaIsrael
- Sackler Faculty of MedicineTel Aviv UniversityTel AvivIsrael
| | - Monika Weisz Hubshman
- Pediatric Genetics Unit, Schneider Children's Medical Center of IsraelPetach TikvaIsrael
- Raphael Recanati Genetic Institute, Rabin Medical CenterPetach TikvaIsrael
- Sackler Faculty of MedicineTel Aviv UniversityTel AvivIsrael
| | - Sharon Aharoni
- Sackler Faculty of MedicineTel Aviv UniversityTel AvivIsrael
- Institute of Child Neurology, Schneider Children's Medical Center of IsraelPetach TikvaIsrael
| | - Adnan Y. Manzur
- Department of Pediatric NeurologyDubowitz Neuromuscular Centre, Great Ormond Street Hospital for Children National Health Service Foundation TrustLondonUnited Kingdom
| | - Brunhilde Wirth
- Institute of Human Genetics, Center for Molecular Medicine CologneCologneGermany
| | - Henry Houlden
- Department of Molecular Neuroscience, Institute of NeurologyUniversity College London Institute of NeurologyLondonUnited Kingdom
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Peng L, Adler M, Demogines A, Borrell A, Liu H, Tao L, Tepp WH, Zhang SC, Johnson EA, Sawyer SL, Dong M. Widespread sequence variations in VAMP1 across vertebrates suggest a potential selective pressure from botulinum neurotoxins. PLoS Pathog 2014; 10:e1004177. [PMID: 25010769 PMCID: PMC4092145 DOI: 10.1371/journal.ppat.1004177] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2014] [Accepted: 04/26/2014] [Indexed: 01/02/2023] Open
Abstract
Botulinum neurotoxins (BoNT/A-G), the most potent toxins known, act by cleaving three SNARE proteins required for synaptic vesicle exocytosis. Previous studies on BoNTs have generally utilized the major SNARE homologues expressed in brain (VAMP2, syntaxin 1, and SNAP-25). However, BoNTs target peripheral motor neurons and cause death by paralyzing respiratory muscles such as the diaphragm. Here we report that VAMP1, but not VAMP2, is the SNARE homologue predominantly expressed in adult rodent diaphragm motor nerve terminals and in differentiated human motor neurons. In contrast to the highly conserved VAMP2, BoNT-resistant variations in VAMP1 are widespread across vertebrates. In particular, we identified a polymorphism at position 48 of VAMP1 in rats, which renders VAMP1 either resistant (I48) or sensitive (M48) to BoNT/D. Taking advantage of this finding, we showed that rat diaphragms with I48 in VAMP1 are insensitive to BoNT/D compared to rat diaphragms with M48 in VAMP1. This unique intra-species comparison establishes VAMP1 as a physiological toxin target in diaphragm motor nerve terminals, and demonstrates that the resistance of VAMP1 to BoNTs can underlie the insensitivity of a species to members of BoNTs. Consistently, human VAMP1 contains I48, which may explain why humans are insensitive to BoNT/D. Finally, we report that residue 48 of VAMP1 varies frequently between M and I across seventeen closely related primate species, suggesting a potential selective pressure from members of BoNTs for resistance in vertebrates. Botulinum neurotoxins (BoNTs) target peripheral motor neurons and act by cleaving SNARE proteins, which are essential for neurotransmitter release from nerve terminals. SNARE proteins occur in multiple homologues and it has been difficult to determine which one is the physiologically relevant toxin target in motor nerve terminals among closely related SNARE homologues such as VAMP1 and VAMP2. Here we report that, in contrast to the highly conserved VAMP2, sequence variations in VAMP1 that confer resistance to BoNTs are widespread across vertebrates. In particular, residue 48 of VAMP1 is polymorphic between BoNT/D-sensitive residue M and BoNT/D-resistant residue I in rats. Taking advantage of this finding, we carried out an intra-species comparison, which showed that diaphragm motor nerve terminals from rats with I48 in VAMP1 were insensitive to BoNT/D as compared to those with M48. Since VAMP2 is conserved in rats, these data demonstrate that VAMP1 is the physiologically relevant toxin target in motor neurons. Interestingly, human VAMP1 encodes the BoNT/D-resistant residue I48, which may explain why humans are insensitive to BoNT/D. Finally, we found that residue 48 of VAMP1 switches frequently between M and I among 17 primate species, suggesting a potential selective pressure from BoNT/D for resistance in primates.
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Affiliation(s)
- Lisheng Peng
- Department of Microbiology and Immunobiology, Harvard Medical School and Division of Neuroscience, New England Primate Research Center, Southborough, Massachusetts, United States of America
| | - Michael Adler
- Neurobehavioral Toxicology Branch, U.S. Army Medical Research Institute of Chemical Defense, Aberdeen Proving Ground, Aberdeen, Maryland, United States of America
- * E-mail: (MA); (SLS); (MD)
| | - Ann Demogines
- Department of Molecular Biosciences, University of Texas, Austin, Texas, United States of America
| | - Andrew Borrell
- Neurobehavioral Toxicology Branch, U.S. Army Medical Research Institute of Chemical Defense, Aberdeen Proving Ground, Aberdeen, Maryland, United States of America
| | - Huisheng Liu
- Waisman Center, Department of Neuroscience, Department of Neurology, University of Wisconsin, Madison, Wisconsin, United States of America
| | - Liang Tao
- Department of Microbiology and Immunobiology, Harvard Medical School and Division of Neuroscience, New England Primate Research Center, Southborough, Massachusetts, United States of America
| | - William H. Tepp
- Department of Bacteriology, University of Wisconsin, Madison, Wisconsin, United States of America
| | - Su-Chun Zhang
- Waisman Center, Department of Neuroscience, Department of Neurology, University of Wisconsin, Madison, Wisconsin, United States of America
| | - Eric A. Johnson
- Department of Bacteriology, University of Wisconsin, Madison, Wisconsin, United States of America
| | - Sara L. Sawyer
- Department of Molecular Biosciences, University of Texas, Austin, Texas, United States of America
- * E-mail: (MA); (SLS); (MD)
| | - Min Dong
- Department of Microbiology and Immunobiology, Harvard Medical School and Division of Neuroscience, New England Primate Research Center, Southborough, Massachusetts, United States of America
- * E-mail: (MA); (SLS); (MD)
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Kosiorek M, Zylinska L, Zablocki K, Pikula S. Calcineurin/NFAT signaling represses genes Vamp1 and Vamp2 via PMCA-dependent mechanism during dopamine secretion by Pheochromocytoma cells. PLoS One 2014; 9:e92176. [PMID: 24667359 PMCID: PMC3965406 DOI: 10.1371/journal.pone.0092176] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2013] [Accepted: 02/19/2014] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Plasma membrane Ca(2+)-ATPases (PMCA) extrude Ca(2+) ions out of the cell and contribute to generation of calcium oscillations. Calcium signaling is crucial for transcriptional regulation of dopamine secretion by neuroendocrine PC12 cells. Low resting [Ca(2+)]c in PC12 cells is maintained mainly by two Ca(2+)-ATPases, PMCA2 and PMCA3. Recently, we found that Ca(2+) dependent phosphatase calcineurin was excessively activated under conditions of experimental downregulation of PMCA2 or PMCA3. Thus, the aim of this study was to explain if, via modulation of the Ca(2+)/calcineurin-dependent nuclear factor of activated T cells (NFAT) pathway, PMCA2 and PMCA3 affect intracellular signaling in pheochromocytoma/neuronal cells/PC12 cells. Secondly, we tested whether this might influence dopamine secretion by PC12 cells. RESULTS PMCA2- and PMCA3-deficient cells displayed profound decrease in dopamine secretion accompanied by a permanent increase in [Ca(2+)]c. Reduction in secretion might result from changes in NFAT signaling, following altered PMCA pattern. Consequently, activation of NFAT1 and NFAT3 transcription factors was observed in PMCA2- or PMCA3-deficient cells. Furthermore, chromatin immunoprecipitation assay indicated that NFATs could be involved in repression of Vamp genes encoding vesicle associated membrane proteins (VAMP). CONCLUSIONS PMCA2 and PMCA3 are crucial for dopamine secretion in PC12 cells. Reduction in PMCA2 or PMCA3 led to calcium-dependent activation of calcineurin/NFAT signaling and, in consequence, to repression of the Vamp gene and deterioration of the SNARE complex formation in PC12 cells.
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Affiliation(s)
- Michalina Kosiorek
- Department of Biochemistry, Nencki Institute of Experimental Biology, PAS, Warsaw, Poland
- Laboratory of Neurogenetics, Department of Neurodegenerative Disorders, Mossakowski Medical Research Centre PAS, Warsaw, Poland
- * E-mail: (MK); (SP)
| | - Ludmila Zylinska
- Department of Molecular Neurochemistry, Medical University, Lodz, Poland
| | - Krzysztof Zablocki
- Department of Biochemistry, Nencki Institute of Experimental Biology, PAS, Warsaw, Poland
| | - Slawomir Pikula
- Department of Biochemistry, Nencki Institute of Experimental Biology, PAS, Warsaw, Poland
- * E-mail: (MK); (SP)
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Coller KE, Heaton NS, Berger KL, Cooper JD, Saunders JL, Randall G. Molecular determinants and dynamics of hepatitis C virus secretion. PLoS Pathog 2012; 8:e1002466. [PMID: 22241992 PMCID: PMC3252379 DOI: 10.1371/journal.ppat.1002466] [Citation(s) in RCA: 134] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2011] [Accepted: 11/16/2011] [Indexed: 12/12/2022] Open
Abstract
The current model of hepatitis C virus (HCV) production involves the assembly of virions on or near the surface of lipid droplets, envelopment at the ER in association with components of VLDL synthesis, and egress via the secretory pathway. However, the cellular requirements for and a mechanistic understanding of HCV secretion are incomplete at best. We combined an RNA interference (RNAi) analysis of host factors for infectious HCV secretion with the development of live cell imaging of HCV core trafficking to gain a detailed understanding of HCV egress. RNAi studies identified multiple components of the secretory pathway, including ER to Golgi trafficking, lipid and protein kinases that regulate budding from the trans-Golgi network (TGN), VAMP1 vesicles and adaptor proteins, and the recycling endosome. Our results support a model wherein HCV is infectious upon envelopment at the ER and exits the cell via the secretory pathway. We next constructed infectious HCV with a tetracysteine (TC) tag insertion in core (TC-core) to monitor the dynamics of HCV core trafficking in association with its cellular cofactors. In order to isolate core protein movements associated with infectious HCV secretion, only trafficking events that required the essential HCV assembly factor NS2 were quantified. TC-core traffics to the cell periphery along microtubules and this movement can be inhibited by nocodazole. Sub-populations of TC-core localize to the Golgi and co-traffic with components of the recycling endosome. Silencing of the recycling endosome component Rab11a results in the accumulation of HCV core at the Golgi. The majority of dynamic core traffics in association with apolipoprotein E (ApoE) and VAMP1 vesicles. This study identifies many new host cofactors of HCV egress, while presenting dynamic studies of HCV core trafficking in infected cells. The current model of HCV egress is that virions assemble at lipid droplets, envelope at the ER and then likely exit the hepatocyte via the secretory pathway in association with apolipoproteins. To gain a more detailed insight into infectious HCV release, we combined an RNAi analysis of host factors that are required for infectious HCV secretion with live cell imaging of HCV core trafficking. Using this approach, we identified numerous components of the secretory pathway that are both required for infectious HCV release and co-traffic with HCV core. The dynamics of HCV core trafficking, both in terms of frequency of transport, particle velocity, and the corresponding run lengths were quantified. We observe that dynamic core movements in the periphery require NS2, a viral protein required for virion assembly. Core co-traffics with multiple components of the secretory pathway, including the Golgi, recycling endosome, microtubules, VAMP1 secretory vesicles, and ApoE. This study identifies new molecular determinants of HCV secretion and describes the dynamics of their movements with HCV core in real time.
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Affiliation(s)
- Kelly E. Coller
- Department of Microbiology, The University of Chicago, Chicago, Illinois, United States of America
| | - Nicholas S. Heaton
- Department of Microbiology, The University of Chicago, Chicago, Illinois, United States of America
| | - Kristi L. Berger
- Department of Microbiology, The University of Chicago, Chicago, Illinois, United States of America
| | - Jacob D. Cooper
- Department of Microbiology, The University of Chicago, Chicago, Illinois, United States of America
| | - Jessica L. Saunders
- Department of Microbiology, The University of Chicago, Chicago, Illinois, United States of America
| | - Glenn Randall
- Department of Microbiology, The University of Chicago, Chicago, Illinois, United States of America
- * E-mail:
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Bümming P, Nilsson O, Ahlman H, Welbencer A, Andersson MK, Sjölund K, Nilsson B. Gastrointestinal stromal tumors regularly express synaptic vesicle proteins: evidence of a neuroendocrine phenotype. Endocr Relat Cancer 2007; 14:853-63. [PMID: 17914114 DOI: 10.1677/erc-06-0014] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Gastrointestinal stromal tumors (GISTs) are thought to originate from the interstitial cells of Cajal, which share many properties with neurons of the gastrointestinal tract. Recently, we demonstrated expression of the hormone ghrelin in GIST. The aim of the present study was therefore to evaluate a possible neuroendocrine phenotype of GIST. Specimens from 41 GISTs were examined for the expression of 12 different synaptic vesicle proteins. Expression of synaptic-like microvesicle proteins, e.g., Synaptic vesicle protein 2 (SV2), synaptobrevin, synapsin 1, and amphiphysin was demonstrated in a majority of GISTs by immunohistochemistry, western blotting, and quantitative reversetranscriptase PCR. One-third of the tumors also expressed the large dense core vesicle protein vesicular monoamine transporter 1. Presence of microvesicles and dense core vesicles in GIST was confirmed by electron microscopy. The expression of synaptic-like microvesicle proteins in GIST was not related to risk profile or to KIT/platelet derived growth factor alpha (PDGFRA) mutational status. Thus, GISTs regularly express a subset of synaptic-like microvesicle proteins necessary for the regulated secretion of neurotransmitters and hormones. Expression of synaptic-like micro-vesicle proteins, ghrelin and peptide hormone receptors in GIST indicate a neuroendocrine phenotype and suggest novel possibilities to treat therapy-resistant GIST.
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Affiliation(s)
- Per Bümming
- Department of Surgery and Pathology, Sahlgrenska Academy at the University of Göteborg, Sahlgrenska University Hospital, Göteborg, Sweden
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Nystuen AM, Schwendinger JK, Sachs AJ, Yang AW, Haider NB. A null mutation in VAMP1/synaptobrevin is associated with neurological defects and prewean mortality in the lethal-wasting mouse mutant. Neurogenetics 2006; 8:1-10. [PMID: 17102983 DOI: 10.1007/s10048-006-0068-7] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2006] [Accepted: 10/02/2006] [Indexed: 10/23/2022]
Abstract
The soluble N-ethylmaleimide sensitive factor attachment receptors are a large family of membrane-associated proteins that are critical for Ca(2+)-mediated synaptic vesicle release. This family includes the VAMP, synaptosomal-associated protein, and syntaxin proteins. In this report, we describe a mutation in vesicle-associated membrane protein 1(VAMP1)/synaptobrevin in the mouse neurological mutant lethal-wasting (lew). The lethal-wasting mutant phenotype is characterized by a general lack of movement and wasting, eventually leading to death before weaning. Mutants are visibly immobile and lay on their side by postnatal day 10 (P10). Before this stage, mutants can be identified by a failure to attempt to right themselves. Affected mice die on average at P15. We used a positional cloning strategy to identify the mutation associated with this neurological phenotype. Lethal wasting had previously been linked to chromosome 6. We further narrowed the genetic disease interval and selected a small number of candidate genes for mutation screening. Genes were evaluated by quantitative reverse transcription-polymerase chain reaction (RT-PCR) to detect differences in their expression levels between control and mutant brain ribonucleic acid (RNA) samples. VAMP1 mRNA was found to be significantly downregulated in the lethal-wasting brain compared to wild-type littermates. Subsequently, a nonsense mutation was identified in the coding region of the gene. This mutation is predicted to truncate approximately half of the protein; however, Western blot analysis showed that no protein is detectable in the mutant. VAMP1 is selectively expressed in the retina and in discrete areas of the brain including the zona incerta and rostral periolivary region, although no gross histological abnormalities were observed in these tissues. Taken together, these data indicate that VAMP1 has a vital role in a subset of central nervous system tissues.
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Affiliation(s)
- Arne M Nystuen
- Department of Genetics, Cell Biology and Anatomy, 6008 Durham Research Center, University of Nebraska Medical Center, Omaha, NE 68198, USA.
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Peters CG, Miller DF, Giovannucci DR. Identification, localization and interaction of SNARE proteins in atrial cardiac myocytes. J Mol Cell Cardiol 2006; 40:361-74. [PMID: 16458920 DOI: 10.1016/j.yjmcc.2005.12.007] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/24/2005] [Revised: 11/14/2005] [Accepted: 12/14/2005] [Indexed: 01/14/2023]
Abstract
Atrial cardiac myocytes secrete the vasoactive hormone atrial natriuretic peptide (ANP) by both constitutive and regulated exocytotic fusion of ANP-containing large dense core vesicles (LDCV) with the sarcolemma. Detailed information, however, regarding the identity and function of specific membrane fusion proteins (SNARE proteins) involved in exocytosis in the endocrine heart is lacking. In the current study, we identified SNARE proteins and determined their association with ANP-containing secretory granules using primary cultures of neonatal and adult rat atrial cardiac myocytes. Using RT-PCR, cardiac myocytes were screened for SNARE and SNARE-associated transcripts. Identified SNARE proteins that have been implicated in exocytosis in neuroendocrine cells were further characterized by Western blot analysis. Functional interaction between SNARE proteins was demonstrated using immunoprecipitation. Using cell fractionation and immunocytochemical methods, it was revealed that VAMP-1, VAMP-2 and synaptotagmin-1 (the putative Ca(2+) sensor) localized to subpopulations of ANP-containing secretory granules in atrial myocytes. Currently, there is conflicting data regarding the role of Ca(2+) in ANP exocytosis. To judge whether secretory activity could be evoked by intracellular Ca(2+) elevation, time-resolved membrane capacitance measurements were used in combination with the flash photolysis of caged compounds to follow the exocytotic activity of single neonatal atrial myocytes. These studies demonstrated that multiple SNARE proteins are present in neonatal and adult cardiac myocytes and suggest the importance of Ca(2+) in exocytosis of ANP from neonatal atrial cardiac myocytes.
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Affiliation(s)
- Christian G Peters
- Department of Neurosciences, Medical University of Ohio, Toledo, OH 43614, USA
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