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Yin L, Xu Y, Yin J, Cheng H, Xiao W, Wu Y, Ji D, Gao S. Construction and validation of a risk model based on the key SNARE proteins to predict the prognosis and immune microenvironment of gliomas. Front Mol Neurosci 2023; 16:1304224. [PMID: 38115820 PMCID: PMC10728289 DOI: 10.3389/fnmol.2023.1304224] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2023] [Accepted: 11/08/2023] [Indexed: 12/21/2023] Open
Abstract
Background Synaptic transmission between neurons and glioma cells can promote glioma progression. The soluble N-ethylmaleimide-sensitive fusion factor attachment protein receptors (SNARE) play a key role in synaptic functions. We aimed to construct and validate a novel model based on the SNARE proteins to predict the prognosis and immune microenvironment of glioma. Methods Differential expression analysis and COX regression analysis were used to identify key SRGs in glioma datasets, and we constructed a prognostic risk model based on the key SRGs. The prognostic value and predictive performance of the model were assessed in The Cancer Genome Atlas (TCGA) and Chinese glioma Genome Atlas (CGGA) datasets. Functional enrichment analysis and immune-related evaluation were employed to reveal the association of risk scores with tumor progression and microenvironment. A prognostic nomogram containing the risk score was established and assessed by calibration curves and time-dependent receiver operating characteristic curves. We verified the changes of the key SRGs in glioma specimens and cells by real-time quantitative PCR and Western blot analyses. Results Vesicle-associated membrane protein 2 (VAMP2) and vesicle-associated membrane protein 5 (VAMP5) were identified as two SRGs affecting the prognoses of glioma patients. High-risk patients characterized by higher VAMP5 and lower VAMP2 expression had a worse prognosis. Higher risk scores were associated with older age, higher tumor grades, IDH wild-type, and 1p19q non-codeletion. The SRGs risk model showed an excellent predictive performance in predicting the prognosis in TCGA and CGGA datasets. Differentially expressed genes between low- and high-risk groups were mainly enriched in the pathways related to immune infiltration, tumor metastasis, and neuronal activity. Immune score, stromal score, estimate score, tumor mutational burden, and expression of checkpoint genes were positively correlated with risk scores. The nomogram containing the risk score showed good performance in predicting the prognosis of glioma. Low VAMP2 and high VAMP5 were found in different grades of glioma specimens and cell lines. Conclusion We constructed and validated a novel risk model based on the expression of VAMP2 and VAMP5 by bioinformatics analysis and experimental confirmation. This model might be helpful for clinically predicting the prognosis and response to immunotherapy of glioma patients.
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Affiliation(s)
- Luxin Yin
- Department of Neurosurgery, The Affiliated Hospital of Xuzhou Medical University, Xuzhou, China
- Institute of Nervous System Diseases, Xuzhou Medical University, Xuzhou, China
| | - Yiqiang Xu
- Department of Neurosurgery, The Affiliated Hospital of Xuzhou Medical University, Xuzhou, China
- Institute of Nervous System Diseases, Xuzhou Medical University, Xuzhou, China
| | - Jiale Yin
- Institute of Nervous System Diseases, Xuzhou Medical University, Xuzhou, China
| | - Hai Cheng
- Department of Neurosurgery, The Affiliated Hospital of Xuzhou Medical University, Xuzhou, China
| | - Weihan Xiao
- Department of Neurosurgery, The Affiliated Hospital of Xuzhou Medical University, Xuzhou, China
| | - Yue Wu
- Institute of Nervous System Diseases, Xuzhou Medical University, Xuzhou, China
- Department of Neurosurgery, The Second Affiliated Hospital of Xuzhou Medical University, Xuzhou, China
| | - Daofei Ji
- Institute of Nervous System Diseases, Xuzhou Medical University, Xuzhou, China
- Department of Neurosurgery, The Second Affiliated Hospital of Xuzhou Medical University, Xuzhou, China
| | - Shangfeng Gao
- Department of Neurosurgery, The Affiliated Hospital of Xuzhou Medical University, Xuzhou, China
- Institute of Nervous System Diseases, Xuzhou Medical University, Xuzhou, China
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Bera M, Radhakrishnan A, Coleman J, K. Sundaram RV, Ramakrishnan S, Pincet F, Rothman JE. Synaptophysin chaperones the assembly of 12 SNAREpins under each ready-release vesicle. Proc Natl Acad Sci U S A 2023; 120:e2311484120. [PMID: 37903271 PMCID: PMC10636311 DOI: 10.1073/pnas.2311484120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2023] [Accepted: 09/19/2023] [Indexed: 11/01/2023] Open
Abstract
The synaptic vesicle protein Synaptophysin (Syp) has long been known to form a complex with the Vesicle associated soluble N-ethylmaleimide sensitive fusion protein attachment receptor (v-SNARE) Vesicle associated membrane protein (VAMP), but a more specific molecular function or mechanism of action in exocytosis has been lacking because gene knockouts have minimal effects. Utilizing fully defined reconstitution and single-molecule measurements, we now report that Syp functions as a chaperone that determines the number of SNAREpins assembling between a ready-release vesicle and its target membrane bilayer. Specifically, Syp directs the assembly of 12 ± 1 SNAREpins under each docked vesicle, even in the face of an excess of SNARE proteins. The SNAREpins assemble in successive waves of 6 ± 1 and 5 ± 2 SNAREpins, respectively, tightly linked to oligomerization of and binding to the vesicle Ca++ sensor Synaptotagmin. Templating of 12 SNAREpins by Syp is likely the direct result of its hexamer structure and its binding of VAMP2 dimers, both of which we demonstrate in detergent extracts and lipid bilayers.
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Affiliation(s)
- Manindra Bera
- Nanobiology Institute, Yale University School of Medicine, New Haven, CT06520
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT06520
| | - Abhijith Radhakrishnan
- Nanobiology Institute, Yale University School of Medicine, New Haven, CT06520
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT06520
| | - Jeff Coleman
- Nanobiology Institute, Yale University School of Medicine, New Haven, CT06520
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT06520
| | - R. Venkat K. Sundaram
- Nanobiology Institute, Yale University School of Medicine, New Haven, CT06520
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT06520
| | - Sathish Ramakrishnan
- Nanobiology Institute, Yale University School of Medicine, New Haven, CT06520
- Department of Pathology, Yale University School of Medicine, New Haven, CT06520
| | - Frederic Pincet
- Nanobiology Institute, Yale University School of Medicine, New Haven, CT06520
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT06520
- Laboratoire de Physique Statistique, Ecole Normale Supérieure, Paris Sciences et Lettres Research University, CNRS, Sorbonne Université, Université de Paris Cité, 75005Paris, France
| | - James E. Rothman
- Nanobiology Institute, Yale University School of Medicine, New Haven, CT06520
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT06520
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Bogue D, Ryan G, Wassmer E, Research Consortium GE, Naik S. VAMP2 Gene-Related Neurodevelopmental Disorder: A Differential Diagnosis for Rett/Angelman-Type Spectrum of Disorders. Mol Syndromol 2023; 14:449-456. [PMID: 37901860 PMCID: PMC10601795 DOI: 10.1159/000530150] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2022] [Accepted: 03/08/2023] [Indexed: 10/31/2023] Open
Abstract
Introduction VAMP2 is an instrumental protein in neuronal synaptic transmission in the brain, facilitating neurotransmitter release. It is encoded by the VAMP2 gene, and pathogenic variants in this gene cause neurodevelopmental features including early onset axial hypotonia, intellectual disability, and features of autism spectrum disorder. To date, only three types of allelic variants (loss of function, in-frame deletions, and missense variants) in the VAMP2 gene have been previously reported in 11 patients with learning difficulties. Here, we describe a patient in whom a novel de novo pathogenic variant in the VAMP2 gene was identified. Case Presentation A 15-month-old girl presented with early onset hypotonia, global developmental delay, learning difficulties, microcephaly, nystagmus, strabismus, and stereotypies. Later, she developed a sleep disorder, challenging behaviour with self-injury, and scoliosis. Gene agnostic analysis of whole genome sequencing data identified a novel de novo heterozygous missense variant c.197G>C (p.Arg66Pro) in the VAMP2 gene SNARE motif region. Discussion This is the fourth report describing VAMP2 gene-related neurodevelopmental disorder. This report adds to the genotype-phenotype correlation and highlights this condition as an important differential diagnosis of Rett/Angelman-type spectrum of disorders. Patients presenting with features of either Rett syndrome or Angelman syndrome, in whom genetic testing is not suggestive, should be evaluated for variants in the VAMP2 gene, given the significant overlap in clinical presentation of these disorders.
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Affiliation(s)
- Danielle Bogue
- West Midlands Clinical Genetics Unit, Birmingham Women’s and Children’s NHS Foundation Trust, Birmingham, UK
| | - Gavin Ryan
- West Midlands Regional Genetics Laboratory, Birmingham Women’s and Children’s NHS Foundation Trust, Birmingham, UK
| | - Evangeline Wassmer
- Department of Neurology, Birmingham Women’s and Children’s NHS Foundation Trust, Birmingham, UK
- Institute of Health and Neurodevelopment, Aston University, Birmingham, UK
| | | | - Swati Naik
- West Midlands Clinical Genetics Unit, Birmingham Women’s and Children’s NHS Foundation Trust, Birmingham, UK
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Bera M, Radhakrishnan A, Coleman J, Sundaram RVK, Ramakrishnan S, Pincet F, Rothman JE. Synaptophysin Chaperones the Assembly of 12 SNAREpins under each Ready-Release Vesicle. bioRxiv 2023:2023.07.05.547834. [PMID: 37461465 PMCID: PMC10349951 DOI: 10.1101/2023.07.05.547834] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 07/24/2023]
Abstract
The synaptic vesicle protein Synaptophysin has long been known to form a complex with the v-SNARE VAMP, but a more specific molecular function or mechanism of action in exocytosis has been lacking because gene knockouts have minimal effects. Utilizing fully-defined reconstitution and single-molecule measurements, we now report that Synaptophysin functions as a chaperone that determines the number of SNAREpins assembling between a ready-release vesicle and its target membrane bilayer. Specifically, Synaptophysin directs the assembly of 12 ± 1 SNAREpins under each docked vesicle, even in the face of an excess of SNARE proteins. The SNAREpins assemble in successive waves of 6 ± 1 and 5 ± 2 SNAREpins, respectively, tightly linked to oligomerization of and binding to the vesicle Ca++ sensor Synaptotagmin. Templating of 12 SNAREpins by Synaptophysin is likely the direct result of its hexamer structure and its binding of VAMP2 dimers, both of which we demonstrate in detergent extracts and lipid bilayers.
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Affiliation(s)
- Manindra Bera
- Nanobiology Institute, Yale University School of Medicine, New Haven, CT 06520, USA
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT 06520, USA
| | - Abhijith Radhakrishnan
- Nanobiology Institute, Yale University School of Medicine, New Haven, CT 06520, USA
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT 06520, USA
| | - Jeff Coleman
- Nanobiology Institute, Yale University School of Medicine, New Haven, CT 06520, USA
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT 06520, USA
| | - Ramalingam Venkat Kalyana Sundaram
- Nanobiology Institute, Yale University School of Medicine, New Haven, CT 06520, USA
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT 06520, USA
| | - Sathish Ramakrishnan
- Nanobiology Institute, Yale University School of Medicine, New Haven, CT 06520, USA
- Department of Pathology, Yale University School of Medicine, New Haven, CT 06520, USA
| | - Frederic Pincet
- Nanobiology Institute, Yale University School of Medicine, New Haven, CT 06520, USA
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT 06520, USA
- Laboratoire de Physique de l’Ecole normale supérieure, ENS, Université PSL, CNRS, Sorbonne Université, Université de Paris, Paris, France
| | - James E. Rothman
- Nanobiology Institute, Yale University School of Medicine, New Haven, CT 06520, USA
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT 06520, USA
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Felício D, Dias A, Martins S, Carvalho E, Lopes AM, Pinto N, Lemos C, Santos M, Alves-Ferreira M. Non-coding variants in VAMP2 and SNAP25 affect gene expression: potential implications in migraine susceptibility. J Headache Pain 2023; 24:78. [PMID: 37380951 DOI: 10.1186/s10194-023-01615-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2023] [Accepted: 06/19/2023] [Indexed: 06/30/2023] Open
Abstract
Migraine is a common and complex neurological disease potentially caused by a polygenic interaction of multiple gene variants. Many genes associated with migraine are involved in pathways controlling the synaptic function and neurotransmitters release. However, the molecular mechanisms underpinning migraine need to be further explored.Recent studies raised the possibility that migraine may arise from the effect of regulatory non-coding variants. In this study, we explored the effect of candidate non-coding variants potentially associated with migraine and predicted to lie within regulatory elements: VAMP2_rs1150, SNAP25_rs2327264, and STX1A_rs6951030. The involvement of these genes, which are constituents of the SNARE complex involved in membrane fusion and neurotransmitter release, underscores their significance in migraine pathogenesis. Our reporter gene assays confirmed the impact of at least two of these non-coding variants. VAMP2 and SNAP25 risk alleles were associated with a decrease and increase in gene expression, respectively, while STX1A risk allele showed a tendency to reduce luciferase activity in neuronal-like cells. Therefore, the VAMP2_rs1150 and SNAP25_rs2327264 non-coding variants affect gene expression, which may have implications in migraine susceptibility. Based on previous in silico analysis, it is plausible that these variants influence the binding of regulators, such as transcription factors and micro-RNAs. Still, further studies exploring these mechanisms would be important to shed light on the association between SNAREs dysregulation and migraine susceptibility.
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Affiliation(s)
- Daniela Felício
- Instituto de Investigação e Inovação em Saúde (i3S), 4200-135, Porto, Portugal
- Institute of Molecular Pathology and Immunology of the University of Porto (IPATIMUP), 4200-135, Porto, Portugal
- ICBAS - School of Medicine and Biomedical Sciences, Universidade Do Porto, 4050-313, Porto, Portugal
| | - Andreia Dias
- Instituto de Investigação e Inovação em Saúde (i3S), 4200-135, Porto, Portugal
- ICBAS - School of Medicine and Biomedical Sciences, Universidade Do Porto, 4050-313, Porto, Portugal
- Unit for Genetic and Epidemiological Research in Neurological Diseases (UnIGENe), Instituto de Biologia Molecular e Celular (IBMC), Universidade do Porto, 4200-135, Porto, Portugal
| | - Sandra Martins
- Instituto de Investigação e Inovação em Saúde (i3S), 4200-135, Porto, Portugal
- Institute of Molecular Pathology and Immunology of the University of Porto (IPATIMUP), 4200-135, Porto, Portugal
| | - Estefânia Carvalho
- Instituto de Investigação e Inovação em Saúde (i3S), 4200-135, Porto, Portugal
- ICBAS - School of Medicine and Biomedical Sciences, Universidade Do Porto, 4050-313, Porto, Portugal
- Unit for Genetic and Epidemiological Research in Neurological Diseases (UnIGENe), Instituto de Biologia Molecular e Celular (IBMC), Universidade do Porto, 4200-135, Porto, Portugal
| | - Alexandra M Lopes
- Instituto de Investigação e Inovação em Saúde (i3S), 4200-135, Porto, Portugal
- Institute of Molecular Pathology and Immunology of the University of Porto (IPATIMUP), 4200-135, Porto, Portugal
- Centre for Predictive and Preventive Genetics (CGPP), Instituto de Biologia Molecular e Celular (IBMC), Universidade do Porto, 4200-135, Porto, Portugal
| | - Nádia Pinto
- Instituto de Investigação e Inovação em Saúde (i3S), 4200-135, Porto, Portugal
- Institute of Molecular Pathology and Immunology of the University of Porto (IPATIMUP), 4200-135, Porto, Portugal
- Centro de Matemática da Universidade do Porto (CMUP), 4169-007, Porto, Portugal
| | - Carolina Lemos
- Instituto de Investigação e Inovação em Saúde (i3S), 4200-135, Porto, Portugal
- ICBAS - School of Medicine and Biomedical Sciences, Universidade Do Porto, 4050-313, Porto, Portugal
- Unit for Genetic and Epidemiological Research in Neurological Diseases (UnIGENe), Instituto de Biologia Molecular e Celular (IBMC), Universidade do Porto, 4200-135, Porto, Portugal
| | - Mariana Santos
- Instituto de Investigação e Inovação em Saúde (i3S), 4200-135, Porto, Portugal
- Unit for Genetic and Epidemiological Research in Neurological Diseases (UnIGENe), Instituto de Biologia Molecular e Celular (IBMC), Universidade do Porto, 4200-135, Porto, Portugal
| | - Miguel Alves-Ferreira
- Instituto de Investigação e Inovação em Saúde (i3S), 4200-135, Porto, Portugal.
- ICBAS - School of Medicine and Biomedical Sciences, Universidade Do Porto, 4050-313, Porto, Portugal.
- Unit for Genetic and Epidemiological Research in Neurological Diseases (UnIGENe), Instituto de Biologia Molecular e Celular (IBMC), Universidade do Porto, 4200-135, Porto, Portugal.
- Centre for Predictive and Preventive Genetics (CGPP), Instituto de Biologia Molecular e Celular (IBMC), Universidade do Porto, 4200-135, Porto, Portugal.
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Raj N, Greune L, Kahms M, Mildner K, Franzkoch R, Psathaki OE, Zobel T, Zeuschner D, Klingauf J, Gerke V. Early Endosomes Act as Local Exocytosis Hubs to Repair Endothelial Membrane Damage. Adv Sci (Weinh) 2023; 10:e2300244. [PMID: 36938863 PMCID: PMC10161044 DOI: 10.1002/advs.202300244] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/11/2023] [Revised: 02/21/2023] [Indexed: 05/06/2023]
Abstract
The plasma membrane of a cell is subject to stresses causing ruptures that must be repaired immediately to preserve membrane integrity and ensure cell survival. Yet, the spatio-temporal membrane dynamics at the wound site and the source of the membrane required for wound repair are poorly understood. Here, it is shown that early endosomes, previously only known to function in the uptake of extracellular material and its endocytic transport, are involved in plasma membrane repair in human endothelial cells. Using live-cell imaging and correlative light and electron microscopy, it is demonstrated that membrane injury triggers a previously unknown exocytosis of early endosomes that is induced by Ca2+ entering through the wound. This exocytosis is restricted to the vicinity of the wound site and mediated by the endosomal soluble N-ethylmaleimide sensitive factor attachment protein receptor (SNARE) VAMP2, which is crucial for efficient membrane repair. Thus, the newly identified Ca2+ -evoked and localized exocytosis of early endosomes supplies the membrane material required for rapid resealing of a damaged plasma membrane, thereby providing the first line of defense against damage in mechanically challenged endothelial cells.
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Affiliation(s)
- Nikita Raj
- Institute of Medical Biochemistry, Centre for Molecular Biology of Inflammation (ZMBE), Cells in Motion Interfaculty Center, University of Münster, 48149, Münster, Germany
| | - Lilo Greune
- Institute of Infectiology, Center for Molecular Biology of Inflammation (ZMBE), University of Münster, 48149, Münster, Germany
| | - Martin Kahms
- Institute of Medical Physics and Biophysics, University of Münster, 48149, Münster, Germany
| | - Karina Mildner
- Electron Microscopy Facility, Max Planck Institute for Molecular Biomedicine, 48149, Münster, Germany
| | - Rico Franzkoch
- Department of Biology, integrated Bioimaging Facility (iBiOs), Center of Cellular Nanoanalytics (CellNanO), University of Osnabrück, 49076, Osnabrück, Germany
| | - Olympia Ekaterini Psathaki
- Department of Biology, integrated Bioimaging Facility (iBiOs), Center of Cellular Nanoanalytics (CellNanO), University of Osnabrück, 49076, Osnabrück, Germany
| | - Thomas Zobel
- Imaging Network, Cells in Motion Interfaculty Centre, University of Münster, 48149, Münster, Germany
| | - Dagmar Zeuschner
- Electron Microscopy Facility, Max Planck Institute for Molecular Biomedicine, 48149, Münster, Germany
| | - Jürgen Klingauf
- Institute of Medical Physics and Biophysics, University of Münster, 48149, Münster, Germany
| | - Volker Gerke
- Institute of Medical Biochemistry, Centre for Molecular Biology of Inflammation (ZMBE), Cells in Motion Interfaculty Center, University of Münster, 48149, Münster, Germany
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Yan C, Jiang J, Yang Y, Geng X, Dong W. The function of VAMP2 in mediating membrane fusion: An overview. Front Mol Neurosci 2022; 15:948160. [PMID: 36618823 PMCID: PMC9816800 DOI: 10.3389/fnmol.2022.948160] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2022] [Accepted: 12/05/2022] [Indexed: 12/24/2022] Open
Abstract
Vesicle-associated membrane protein 2 (VAMP2, also known as synaptobrevin-2), encoded by VAMP2 in humans, is a key component of the soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) complex. VAMP2 combined with syntaxin-1A (SYX-1A) and synaptosome-associated protein 25 (SNAP-25) produces a force that induces the formation of fusion pores, thereby mediating the fusion of synaptic vesicles and the release of neurotransmitters. VAMP2 is largely unstructured in the absence of interaction partners. Upon interaction with other SNAREs, the structure of VAMP2 stabilizes, resulting in the formation of four structural domains. In this review, we highlight the current knowledge of the roles of the VAMP2 domains and the interaction between VAMP2 and various fusion-related proteins in the presynaptic cytoplasm during the fusion process. Our summary will contribute to a better understanding of the roles of the VAMP2 protein in membrane fusion.
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Affiliation(s)
- Chong Yan
- Key Laboratory of Medical Electrophysiology, Ministry of Education and Medical Electrophysiological Key Laboratory of Sichuan Province, Institute of Cardiovascular Research, Southwest Medical University, Luzhou, Sichuan, China
| | - Jie Jiang
- Key Laboratory of Medical Electrophysiology, Ministry of Education and Medical Electrophysiological Key Laboratory of Sichuan Province, Institute of Cardiovascular Research, Southwest Medical University, Luzhou, Sichuan, China
| | - Yuan Yang
- Key Laboratory of Medical Electrophysiology, Ministry of Education and Medical Electrophysiological Key Laboratory of Sichuan Province, Institute of Cardiovascular Research, Southwest Medical University, Luzhou, Sichuan, China
| | - Xiaoqi Geng
- Department of Neurosurgery, Neurosurgical Clinical Research Center of Sichuan Province, Affiliated Hospital of Southwest Medical University, Luzhou, China,*Correspondence: Xiaoqi Geng,
| | - Wei Dong
- Key Laboratory of Medical Electrophysiology, Ministry of Education and Medical Electrophysiological Key Laboratory of Sichuan Province, Institute of Cardiovascular Research, Southwest Medical University, Luzhou, Sichuan, China,Wei Dong,
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Yoo G, An HJ, Yeou S, Lee NK. α-Synuclein Disrupts Vesicle Fusion by Two Mutant-Specific Mechanisms. Mol Cells 2022; 45:806-819. [PMID: 36380732 PMCID: PMC9676983 DOI: 10.14348/molcells.2022.0102] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2022] [Revised: 07/26/2022] [Accepted: 07/28/2022] [Indexed: 11/17/2022] Open
Abstract
Synaptic accumulation of α-synuclein (α-Syn) oligomers and their interactions with VAMP2 have been reported to be the basis of synaptic dysfunction in Parkinson's disease (PD). α-Syn mutants associated with familial PD have also been known to be capable of interacting with VAMP2, but the exact mechanisms resulting from those interactions to eventual synaptic dysfunction are still unclear. Here, we investigate the effect of α-Syn mutant oligomers comprising A30P, E46K, and A53T on VAMP2-embedded vesicles. Specifically, A30P and A53T oligomers cluster vesicles in the presence of VAMP2, which is a shared mechanism with wild type α-Syn oligomers induced by dopamine. On the other hand, E46K oligomers reduce the membrane mobility of the planar bilayers, as revealed by single-particle tracking, and permeabilize the membranes in the presence of VAMP2. In the absence of VAMP2 interactions, E46K oligomers enlarge vesicles by fusing with one another. Our results clearly demonstrate that α-Syn mutant oligomers have aberrant effects on VAMP2-embedded vesicles and the disruption types are distinct depending on the mutant types. This work may provide one of the possible clues to explain the α-Syn mutant-type dependent pathological heterogeneity of familial PD.
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Affiliation(s)
- Gyeongji Yoo
- Department of Chemistry, Seoul National University, Seoul 08826, Korea
| | - Hyeong Jeon An
- Department of Physics, Pohang University of Science and Technology, Pohang 37673, Korea
| | - Sanghun Yeou
- Department of Chemistry, Seoul National University, Seoul 08826, Korea
| | - Nam Ki Lee
- Department of Chemistry, Seoul National University, Seoul 08826, Korea
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Cornejo PJ, Vergoni B, Ohanna M, Angot B, Gonzalez T, Jager J, Tanti JF, Cormont M. The Stress-Responsive microRNA-34a Alters Insulin Signaling and Actions in Adipocytes through Induction of the Tyrosine Phosphatase PTP1B. Cells 2022; 11:cells11162581. [PMID: 36010657 PMCID: PMC9406349 DOI: 10.3390/cells11162581] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2022] [Revised: 08/02/2022] [Accepted: 08/05/2022] [Indexed: 11/18/2022] Open
Abstract
Metabolic stresses alter the signaling and actions of insulin in adipocytes during obesity, but the molecular links remain incompletely understood. Members of the microRNA-34 (miR-34 family play a pivotal role in stress response, and previous studies showed an upregulation of miR-34a in adipose tissue during obesity. Here, we identified miR-34a as a new mediator of adipocyte insulin resistance. We confirmed the upregulation of miR-34a in adipose tissues of obese mice, which was observed in the adipocyte fraction exclusively. Overexpression of miR-34a in 3T3-L1 adipocytes or in fat pads of lean mice markedly reduced Akt activation by insulin and the insulin-induced glucose transport. This was accompanied by a decreased expression of VAMP2, a target of miR-34a, and an increased expression of the tyrosine phosphatase PTP1B. Importantly, PTP1B silencing prevented the inhibitory effect of miR-34a on insulin signaling. Mechanistically, miR-34a decreased the NAD+ level through inhibition of Naprt and Nampt, resulting in an inhibition of Sirtuin-1, which promoted an upregulation of PTP1B. Furthermore, the mRNA expression of Nampt and Naprt was decreased in adipose tissue of obese mice. Collectively, our results identify miR-34a as a new inhibitor of insulin signaling in adipocytes, providing a potential pathway to target to fight insulin resistance.
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Affiliation(s)
- Pierre-Jean Cornejo
- Université Côte d’Azur, Inserm, C3M, Team “Molecular and Cellular Physiopathology of Obesity and Diabetes”, 06204 Nice, France
| | - Bastien Vergoni
- Université Côte d’Azur, Inserm, C3M, Team “Molecular and Cellular Physiopathology of Obesity and Diabetes”, 06204 Nice, France
| | - Mickaël Ohanna
- Université Côte d’Azur, Inserm, C3M, “Team Microenvironnement, Signalisation et Cancer”, 06204 Nice, France
| | - Brice Angot
- Université Côte d’Azur, Inserm, C3M, Team “Molecular and Cellular Physiopathology of Obesity and Diabetes”, 06204 Nice, France
| | - Teresa Gonzalez
- Université Côte d’Azur, Inserm, C3M, Team “Molecular and Cellular Physiopathology of Obesity and Diabetes”, 06204 Nice, France
- Aix Marseille Université, Inserm, INRAE, C2VN, 13385 Marseille, France
| | - Jennifer Jager
- Université Côte d’Azur, Inserm, C3M, Team “Molecular and Cellular Physiopathology of Obesity and Diabetes”, 06204 Nice, France
| | - Jean-François Tanti
- Université Côte d’Azur, Inserm, C3M, Team “Molecular and Cellular Physiopathology of Obesity and Diabetes”, 06204 Nice, France
| | - Mireille Cormont
- Université Côte d’Azur, Inserm, C3M, Team “Molecular and Cellular Physiopathology of Obesity and Diabetes”, 06204 Nice, France
- Correspondence: ; Tel.: +33-4-89-15-38-31
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10
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Islam R, Mishra J, Polavaram NS, Bhattacharya S, Hong Z, Bodas S, Sharma S, Bouska A, Gilbreath T, Said AM, Smith LM, Teply BA, Muders MH, Batra SK, Datta K, Dutta S. Neuropilin-2 axis in regulating secretory phenotype of neuroendocrine-like prostate cancer cells and its implication in therapy resistance. Cell Rep 2022; 40:111097. [PMID: 35858551 PMCID: PMC9362995 DOI: 10.1016/j.celrep.2022.111097] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2021] [Revised: 04/06/2022] [Accepted: 06/23/2022] [Indexed: 12/25/2022] Open
Abstract
Neuroendocrine (NE)-like tumors secrete various signaling molecules to establish paracrine communication within the tumor milieu and to create a therapy-resistant environment. It is important to identify molecular mediators that regulate this secretory phenotype in NE-like cancer. The current study highlights the importance of a cell surface molecule, Neuropilin-2 (NRP2), for the secretory function of NE-like prostate cancer (PCa). Our analysis on different patient cohorts suggests that NRP2 is high in NE-like PCa. We have developed cell line models to investigate NRP2's role in NE-like PCa. Our bioinformatics, mass spectrometry, cytokine array, and other supporting experiments reveal that NRP2 regulates robust secretory phenotype in NE-like PCa and controls the secretion of factors promoting cancer cell survival. Depletion of NRP2 reduces the secretion of these factors and makes resistant cancer cells sensitive to chemotherapy in vitro and in vivo. Therefore, targeting NRP2 can revert cellular secretion and sensitize PCa cells toward therapy.
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Affiliation(s)
- Ridwan Islam
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, BCC, Omaha, NE 68198, USA
| | - Juhi Mishra
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, BCC, Omaha, NE 68198, USA
| | - Navatha Shree Polavaram
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, BCC, Omaha, NE 68198, USA
| | - Sreyashi Bhattacharya
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, BCC, Omaha, NE 68198, USA
| | - Zhengdong Hong
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, BCC, Omaha, NE 68198, USA
| | - Sanika Bodas
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, BCC, Omaha, NE 68198, USA
| | - Sunandini Sharma
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, BCC, Omaha, NE 68198, USA
| | - Alyssa Bouska
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, BCC, Omaha, NE 68198, USA
| | - Tyler Gilbreath
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, BCC, Omaha, NE 68198, USA
| | - Ahmed M Said
- Department of Pharmaceutical Organic Chemistry, Faculty of Pharmacy, Helwan University, Ein-Helwan, Helwan, Cairo, Egypt
| | - Lynette M Smith
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, BCC, Omaha, NE 68198, USA
| | - Benjamin A Teply
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, BCC, Omaha, NE 68198, USA
| | - Michael H Muders
- Department of Prostate Cancer Research, Center for Pathology, University of Bonn Medical Center, Bonn, Germany
| | - Surinder K Batra
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, BCC, Omaha, NE 68198, USA
| | - Kaustubh Datta
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, BCC, Omaha, NE 68198, USA.
| | - Samikshan Dutta
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, BCC, Omaha, NE 68198, USA.
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11
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Parveen S, Khamari A, Raju J, Coppolino MG, Datta S. Syntaxin 7 contributes to breast cancer cell invasion by promoting invadopodia formation. J Cell Sci 2022; 135:275829. [PMID: 35762511 DOI: 10.1242/jcs.259576] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2021] [Accepted: 05/12/2022] [Indexed: 12/15/2022] Open
Abstract
Invasion in various cancer cells requires coordinated delivery of signaling proteins, adhesion proteins, actin-remodeling proteins and proteases to matrix-degrading structures called invadopodia. Vesicular trafficking involving SNAREs plays a crucial role in the delivery of cargo to the target membrane. Screening of 13 SNAREs from the endocytic and recycling route using a gene silencing approach coupled with functional assays identified syntaxin 7 (STX7) as an important player in MDA-MB-231 cell invasion. Total internal reflection fluorescence microscopy (TIRF-M) studies revealed that STX7 resides near invadopodia and co-traffics with MT1-MMP (also known as MMP14), indicating a possible role for this SNARE in protease trafficking. STX7 depletion reduced the number of invadopodia and their associated degradative activity. Immunoprecipitation studies revealed that STX7 forms distinct SNARE complexes with VAMP2, VAMP3, VAMP7, STX4 and SNAP23. Depletion of VAMP2, VAMP3 or STX4 abrogated invadopodia formation, phenocopying what was seen upon lack of STX7. Whereas depletion of STX4 reduced MT1-MMP level at the cell surfaces, STX7 silencing significantly reduced the invadopodia-associated MT1-MMP pool and increased the non-invadosomal pool. This study highlights STX7 as a major contributor towards the invadopodia formation during cancer cell invasion. This article has an associated First Person interview with the first author of the paper.
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Affiliation(s)
- Sameena Parveen
- Department of Biological Sciences, Indian Institute of Science Education and Research, Bhopal, Bhopal 462066, India
| | - Amrita Khamari
- Department of Biological Sciences, Indian Institute of Science Education and Research, Bhopal, Bhopal 462066, India
| | - Jyothikamala Raju
- Thazhathemalayil House, Thodupuzha East PO, Keerikode, Kerala 685585, India
| | - Marc G Coppolino
- Department of Molecular and Cellular Biology, University of Guelph, Ontario N1G 2W1, Canada
| | - Sunando Datta
- Department of Biological Sciences, Indian Institute of Science Education and Research, Bhopal, Bhopal 462066, India
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12
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Fouke KE, Wegman ME, Weber SA, Brady EB, Román-Vendrell C, Morgan JR. Synuclein Regulates Synaptic Vesicle Clustering and Docking at a Vertebrate Synapse. Front Cell Dev Biol 2021; 9:774650. [PMID: 34901020 PMCID: PMC8660973 DOI: 10.3389/fcell.2021.774650] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2021] [Accepted: 11/10/2021] [Indexed: 11/17/2022] Open
Abstract
Neurotransmission relies critically on the exocytotic release of neurotransmitters from small synaptic vesicles (SVs) at the active zone. Therefore, it is essential for neurons to maintain an adequate pool of SVs clustered at synapses in order to sustain efficient neurotransmission. It is well established that the phosphoprotein synapsin 1 regulates SV clustering at synapses. Here, we demonstrate that synuclein, another SV-associated protein and synapsin binding partner, also modulates SV clustering at a vertebrate synapse. When acutely introduced to unstimulated lamprey reticulospinal synapses, a pan-synuclein antibody raised against the N-terminal domain of α-synuclein induced a significant loss of SVs at the synapse. Both docked SVs and the distal reserve pool of SVs were depleted, resulting in a loss of total membrane at synapses. In contrast, antibodies against two other abundant SV-associated proteins, synaptic vesicle glycoprotein 2 (SV2) and vesicle-associated membrane protein (VAMP/synaptobrevin), had no effect on the size or distribution of SV clusters. Synuclein perturbation caused a dose-dependent reduction in the number of SVs at synapses. Interestingly, the large SV clusters appeared to disperse into smaller SV clusters, as well as individual SVs. Thus, synuclein regulates clustering of SVs at resting synapses, as well as docking of SVs at the active zone. These findings reveal new roles for synuclein at the synapse and provide critical insights into diseases associated with α-synuclein dysfunction, such as Parkinson’s disease.
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Affiliation(s)
- Kaitlyn E Fouke
- The Eugene Bell Center for Regenerative Biology and Tissue Engineering, Marine Biological Laboratory, Woods Hole, MA, United States.,Department of Neurobiology, Duke University, Durham, NC, United States
| | - M Elizabeth Wegman
- The Eugene Bell Center for Regenerative Biology and Tissue Engineering, Marine Biological Laboratory, Woods Hole, MA, United States
| | - Sarah A Weber
- The Eugene Bell Center for Regenerative Biology and Tissue Engineering, Marine Biological Laboratory, Woods Hole, MA, United States.,Biological Sciences Collegiate Division, The University of Chicago, Chicago, IL, United States
| | - Emily B Brady
- The Eugene Bell Center for Regenerative Biology and Tissue Engineering, Marine Biological Laboratory, Woods Hole, MA, United States
| | - Cristina Román-Vendrell
- The Eugene Bell Center for Regenerative Biology and Tissue Engineering, Marine Biological Laboratory, Woods Hole, MA, United States
| | - Jennifer R Morgan
- The Eugene Bell Center for Regenerative Biology and Tissue Engineering, Marine Biological Laboratory, Woods Hole, MA, United States
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13
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Li P, Li Y, Ma L. Long noncoding RNA highly upregulated in liver cancer promotes the progression of hepatocellular carcinoma and attenuates the chemosensitivity of oxaliplatin by regulating miR-383-5p/vesicle-associated membrane protein-2 axis. Pharmacol Res Perspect 2021; 9:e00815. [PMID: 34223709 PMCID: PMC8256430 DOI: 10.1002/prp2.815] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2021] [Revised: 03/02/2021] [Accepted: 03/03/2021] [Indexed: 12/14/2022] Open
Abstract
We aimed to explore the function and underlying mechanism of highly upregulated in liver cancer (HULC; an long noncoding RNAs) in hepatocellular carcinoma (HCC) and chemosensitivity of oxaliplatin (Oxa). The expression of HULC, miR-383-5p, and vesicle-associated membrane protein-2 (VAMP2) was detected by quantitative real-time polymerase chain reaction. Western blot assay was applied for measuring the protein expression of cyclinD1, cleaved-caspase-3, light Chain 3 I/II, p62, and VAMP2. Cell viability and Oxa IC50 value were determined by Cell Counting Kit-8 assay. A colony formation assay was conducted to evaluate colony formation ability. Cell apoptosis was assessed by flow cytometry. The interaction between miR-383-5p and HULC or VAMP2 was predicted by bioinformatics analysis and verified by dual-luciferase reporter assay and RNA immunoprecipitation assay. The mice xenograft model was established to investigate the roles of HULC in vivo. HULC and VAMP2 were overexpressed whereas miR-383-5p was lowly expressed in HCC tissues. HULC overexpression promoted the progression of HCC cells and inhibited chemosensitivity of Oxa by increasing cell proliferation and protective autophagy and inhibiting apoptosis, whereas HULC silence presented opposite effects. Moreover, miR-383-5p was a direct target of HULC and miR-383-5p reversed the effects of HULC on the progression of HCC cells and chemosensitivity of Oxa. Besides, HULC acted as a molecular sponge of miR-383-5p to regulate VAMP2 expression. HULC promoted the progression of HCC and inhibited Oxa sensitivity by regulating miR-383-5p/VAMP2 axis, elucidating a novel regulatory mechanism for chemosensitivity of Oxa and providing a potential lncRNA-targeted therapy for HCC.
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Affiliation(s)
- Peng Li
- Department of LaboratoryFirst Affiliated Hospital of Xi'an Jiaotong UniversityXi’anPR China
| | - Yuwei Li
- Department of Genetic CenterNorthwest Women’s and Children’s HospitalXi’anPR China
| | - Lieting Ma
- Department of LaboratoryFirst Affiliated Hospital of Xi'an Jiaotong UniversityXi’anPR China
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14
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Fan YY, Zhong YW, Zhao J, Chi Y, Bouvaine S, Liu SS, Seal SE, Wang XW. Bemisia tabaci Vesicle-Associated Membrane Protein 2 Interacts with Begomoviruses and Plays a Role in Virus Acquisition. Cells 2021; 10:1700. [PMID: 34359870 PMCID: PMC8306474 DOI: 10.3390/cells10071700] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2021] [Revised: 06/29/2021] [Accepted: 06/29/2021] [Indexed: 12/03/2022] Open
Abstract
Begomoviruses cause substantial losses to agricultural production, especially in tropical and subtropical regions, and are exclusively transmitted by members of the whitefly Bemisia tabaci species complex. However, the molecular mechanisms underlying the transmission of begomoviruses by their whitefly vector are not clear. In this study, we found that B. tabaci vesicle-associated membrane protein 2 (BtVAMP2) interacts with the coat protein (CP) of tomato yellow leaf curl virus (TYLCV), an emergent begomovirus that seriously impacts tomato production globally. After infection with TYLCV, the transcription of BtVAMP2 was increased. When the BtVAMP2 protein was blocked by feeding with a specific BtVAMP2 antibody, the quantity of TYLCV in B. tabaci whole body was significantly reduced. BtVAMP2 was found to be conserved among the B. tabaci species complex and also interacts with the CP of Sri Lankan cassava mosaic virus (SLCMV). When feeding with BtVAMP2 antibody, the acquisition quantity of SLCMV in whitefly whole body was also decreased significantly. Overall, our results demonstrate that BtVAMP2 interacts with the CP of begomoviruses and promotes their acquisition by whitefly.
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Affiliation(s)
- Yun-Yun Fan
- Ministry of Agriculture Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Institute of Insect Sciences, Zhejiang University, Hangzhou 310058, China; (Y.-Y.F.); (Y.-W.Z.); (J.Z.); (Y.C.); (S.-S.L.)
| | - Yu-Wei Zhong
- Ministry of Agriculture Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Institute of Insect Sciences, Zhejiang University, Hangzhou 310058, China; (Y.-Y.F.); (Y.-W.Z.); (J.Z.); (Y.C.); (S.-S.L.)
| | - Jing Zhao
- Ministry of Agriculture Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Institute of Insect Sciences, Zhejiang University, Hangzhou 310058, China; (Y.-Y.F.); (Y.-W.Z.); (J.Z.); (Y.C.); (S.-S.L.)
| | - Yao Chi
- Ministry of Agriculture Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Institute of Insect Sciences, Zhejiang University, Hangzhou 310058, China; (Y.-Y.F.); (Y.-W.Z.); (J.Z.); (Y.C.); (S.-S.L.)
| | - Sophie Bouvaine
- Natural Resources Institute, University of Greenwich, Chatham, Kent ME4 4TB, UK;
| | - Shu-Sheng Liu
- Ministry of Agriculture Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Institute of Insect Sciences, Zhejiang University, Hangzhou 310058, China; (Y.-Y.F.); (Y.-W.Z.); (J.Z.); (Y.C.); (S.-S.L.)
| | - Susan E. Seal
- Natural Resources Institute, University of Greenwich, Chatham, Kent ME4 4TB, UK;
| | - Xiao-Wei Wang
- Ministry of Agriculture Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Institute of Insect Sciences, Zhejiang University, Hangzhou 310058, China; (Y.-Y.F.); (Y.-W.Z.); (J.Z.); (Y.C.); (S.-S.L.)
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15
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Lin Z, Zhou L, Li Y, Liu S, Xie Q, Xu X, Wu J. Identification of potential genomic biomarkers for Parkinson's disease using data pooling of gene expression microarrays. Biomark Med 2021; 15:585-595. [PMID: 33988461 DOI: 10.2217/bmm-2020-0325] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Aim: In this study, we aimed to identify potential diagnostic biomarkers Parkinson's disease (PD) by exploring microarray gene expression data of PD patients. Materials & methods: Differentially expressed genes associated with PD were screened from the GSE99039 dataset using weighted gene co-expression network analysis, followed by gene ontology and Kyoto Encyclopedia of Genes and Genomes pathway enrichment analyses, gene-gene interaction network analysis and receiver operator characteristics analysis. Results: We identified two PD-associated modules, in which genes from the chemokine signaling pathway were primarily enriched. In particular, CS, PRKCD, RHOG and VAMP2 directly interacted with known PD-associated genes and showed higher expression in the PD samples, and may thus be potential biomarkers in PD diagnosis. Conclusion: A DFG-analysis identified a four-gene panel (CS, PRKCD, RHOG, VAMP2) as a potential diagnostic predictor to diagnose PD.
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Affiliation(s)
- Zhijian Lin
- Department of Neurology, Peking University Shenzhen Hospital, Shenzhen, 518036, PR China
| | - Lishu Zhou
- Department of Neurology, Peking University Shenzhen Hospital, Shenzhen, 518036, PR China.,The Clinical College of Peking University, Shenzhen Hospital of Anhui Medical University, Shenzhen, 518036, PR China
| | - Yaosha Li
- Department of Neurology, Peking University Shenzhen Hospital, Shenzhen, 518036, PR China
| | - Suni Liu
- Department of Neurology, Peking University Shenzhen Hospital, Shenzhen, 518036, PR China
| | - Qizhi Xie
- Department of Neurology, Peking University Shenzhen Hospital, Shenzhen, 518036, PR China
| | - Xu Xu
- College of Life Sciences & Oceanography, Shenzhen University, Shenzhen, 518060, PR China
| | - Jun Wu
- Department of Neurology, Peking University Shenzhen Hospital, Shenzhen, 518036, PR China
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16
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Abstract
Neurodegenerative diseases are pathologies of the central and peripheral nervous systems characterized by loss of brain functions and problems in movement which occur due to the slow and progressive degeneration of cellular elements. Several neurodegenerative diseases are known such as Alzheimer’s disease, Parkinson’s disease and amyotrophic lateral sclerosis and many studies on the molecular mechanisms underlying these pathologies have been conducted. Altered functions of some key proteins and the presence of intraneuronal aggregates have been identified as responsible for the development of the diseases. Interestingly, the formation of the SNARE complex has been discovered to be fundamental for vesicle fusion, vesicle recycling and neurotransmitter release. Indeed, inhibition of the formation of the SNARE complex, defects in the SNARE-dependent exocytosis and altered regulation of SNARE-mediated vesicle fusion have been associated with neurodegeneration. In this review, the biological aspects of neurodegenerative diseases and the role of SNARE proteins in relation to the onset of these pathologies are described.
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17
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Rahimi R, Malek I, Lerrer-Goldshtein T, Elkis Y, Shoval I, Jacob A, Shpungin S, Nir U. TMF1 is upregulated by insulin and is required for a sustained glucose homeostasis. FASEB J 2021; 35:e21295. [PMID: 33475194 DOI: 10.1096/fj.202001995r] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2020] [Revised: 11/20/2020] [Accepted: 12/07/2020] [Indexed: 01/14/2023]
Abstract
Insulin-regulated glucose homeostasis is a critical and intricate physiological process, of which not all regulatory components have been deciphered. One of the key players in modulating glucose uptake by cells is the glucose transporter-GLUT4. In this study, we aimed to explore the regulatory role of the trans-Golgi-associated protein-TATA Element Modulatory Factor (TMF1) in the GLUT4 mediated, insulin-directed glucose uptake. By establishing and using TMF1-/- myoblasts and mice, we examined the effect of TMF1 absence on the insulin driven functioning of GLUT4. We show that TMF1 is upregulated by insulin in myoblasts, and is essential for the formation of insulin responsive, glucose transporter GLUT4-containing vesicles. Absence of TMF1 leads to the retention of GLUT4 in perinuclear compartments, and to severe impairment of insulin-stimulated GLUT4 trafficking throughout the cytoplasm and to the cell plasma membrane. Accordingly, glucose uptake is impaired in TMF1-/- cells, and TMF1-/- mice are hyperglycemic. This is reflected by the mice impaired blood glucose clearance and increased blood glucose level. Correspondingly, TMF1-/- animals are leaner than their normal littermates. Thus, TMF1 is a novel effector of insulin-regulated glucose homeostasis, and dys-functioning of this protein may contribute to the onset of a diabetes-like disorder.
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Affiliation(s)
- Roni Rahimi
- The Mina and Everard Goodman Faculty of Life-Sciences, Bar-Ilan University, Ramat-Gan, Israel
| | - Israel Malek
- The Mina and Everard Goodman Faculty of Life-Sciences, Bar-Ilan University, Ramat-Gan, Israel
| | - Tali Lerrer-Goldshtein
- The Mina and Everard Goodman Faculty of Life-Sciences, Bar-Ilan University, Ramat-Gan, Israel
| | - Yoav Elkis
- The Mina and Everard Goodman Faculty of Life-Sciences, Bar-Ilan University, Ramat-Gan, Israel
| | - Irit Shoval
- The Mina and Everard Goodman Faculty of Life-Sciences, Bar-Ilan University, Ramat-Gan, Israel
| | - Avi Jacob
- The Mina and Everard Goodman Faculty of Life-Sciences, Bar-Ilan University, Ramat-Gan, Israel
| | - Sally Shpungin
- The Mina and Everard Goodman Faculty of Life-Sciences, Bar-Ilan University, Ramat-Gan, Israel
| | - Uri Nir
- The Mina and Everard Goodman Faculty of Life-Sciences, Bar-Ilan University, Ramat-Gan, Israel
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18
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André T, Classen J, Brenner P, Betts MJ, Dörr B, Kreye S, Zuidinga B, Meijer M, Russell RB, Verhage M, Söllner TH. The Interaction of Munc18-1 Helix 11 and 12 with the Central Region of the VAMP2 SNARE Motif Is Essential for SNARE Templating and Synaptic Transmission. eNeuro 2020; 7:ENEURO.0278-20.2020. [PMID: 33055194 PMCID: PMC7768276 DOI: 10.1523/eneuro.0278-20.2020] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2020] [Revised: 08/13/2020] [Accepted: 08/24/2020] [Indexed: 01/11/2023] Open
Abstract
Sec1/Munc18 proteins play a key role in initiating the assembly of N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) complexes, the molecular fusion machinery. Employing comparative structure modeling, site specific crosslinking by single amino acid substitutions with the photoactivatable unnatural amino acid p-Benzoyl-phenylalanine (Bpa) and reconstituted vesicle docking/fusion assays, we mapped the binding interface between Munc18-1 and the neuronal v-SNARE VAMP2 with single amino acid resolution. Our results show that helices 11 and 12 of domain 3a in Munc18-1 interact with the VAMP2 SNARE motif covering the region from layers -4 to +5. Residue Q301 in helix 11 plays a pivotal role in VAMP2 binding and template complex formation. A VAMP2 binding deficient mutant, Munc18-1 Q301D, does not stimulate lipid mixing in a reconstituted fusion assay. The neuronal SNARE-organizer Munc13-1, which also binds VAMP2, does not bypass the requirement for the Munc18-1·VAMP2 interaction. Importantly, Munc18-1 Q301D expression in Munc18-1 deficient neurons severely reduces synaptic transmission, demonstrating the physiological significance of the Munc18-1·VAMP2 interaction.
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Affiliation(s)
- Timon André
- Heidelberg University Biochemistry Center, Heidelberg 69120, Germany
| | | | - Philipp Brenner
- Heidelberg University Biochemistry Center, Heidelberg 69120, Germany
| | - Matthew J Betts
- Heidelberg University Biochemistry Center, Heidelberg 69120, Germany
- BioQuant, Heidelberg University, Heidelberg 69120, Germany
| | - Bernhard Dörr
- Heidelberg University Biochemistry Center, Heidelberg 69120, Germany
| | - Susanne Kreye
- Heidelberg University Biochemistry Center, Heidelberg 69120, Germany
| | | | - Marieke Meijer
- Clinical Genetics, Center for Neurogenomics and Cognitive Research (CNCR) Amsterdam Neuroscience, VU University and University Medical Center Amsterdam (UMCA), Amsterdam 1081HV, The Netherlands
| | - Robert B Russell
- Heidelberg University Biochemistry Center, Heidelberg 69120, Germany
- BioQuant, Heidelberg University, Heidelberg 69120, Germany
| | - Matthijs Verhage
- Department of Functional Genomics
- Clinical Genetics, Center for Neurogenomics and Cognitive Research (CNCR) Amsterdam Neuroscience, VU University and University Medical Center Amsterdam (UMCA), Amsterdam 1081HV, The Netherlands
| | - Thomas H Söllner
- Heidelberg University Biochemistry Center, Heidelberg 69120, Germany
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19
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Simmons RL, Li H, Alten B, Santos MS, Jiang R, Paul B, Lalani SJ, Cortesi A, Parks K, Khandelwal N, Smith-Packard B, Phoong MA, Chez M, Fisher H, Scheuerle AE, Shinawi M, Hussain SA, Kavalali ET, Sherr EH, Voglmaier SM. Overcoming presynaptic effects of VAMP2 mutations with 4-aminopyridine treatment. Hum Mutat 2020; 41:1999-2011. [PMID: 32906212 PMCID: PMC10898792 DOI: 10.1002/humu.24109] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2020] [Revised: 08/03/2020] [Accepted: 09/04/2020] [Indexed: 12/18/2022]
Abstract
Clinical and genetic features of five unrelated patients with de novo pathogenic variants in the synaptic vesicle-associated membrane protein 2 (VAMP2) reveal common features of global developmental delay, autistic tendencies, behavioral disturbances, and a higher propensity to develop epilepsy. For one patient, a cognitively impaired adolescent with a de novo stop-gain VAMP2 mutation, we tested a potential treatment strategy, enhancing neurotransmission by prolonging action potentials with the aminopyridine family of potassium channel blockers, 4-aminopyridine and 3,4-diaminopyridine, in vitro and in vivo. Synaptic vesicle recycling and neurotransmission were assayed in neurons expressing three VAMP2 variants by live-cell imaging and electrophysiology. In cellular models, two variants decrease both the rate of exocytosis and the number of synaptic vesicles released from the recycling pool, compared with wild-type. Aminopyridine treatment increases the rate and extent of exocytosis and total synaptic charge transfer and desynchronizes GABA release. The clinical response of the patient to 2 years of off-label aminopyridine treatment includes improved emotional and behavioral regulation by parental report, and objective improvement in standardized cognitive measures. Aminopyridine treatment may extend to patients with pathogenic variants in VAMP2 and other genes influencing presynaptic function or GABAergic tone, and tested in vitro before treatment.
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Affiliation(s)
- Roxanne L. Simmons
- Department of Neurology, Weill Institute for Neurosciences and Institute of Human Genetics. University of California San Francisco, School of Medicine, San Francisco, CA, USA
| | - Haiyan Li
- Department of Psychiatry, Weill Institute for Neurosciences and Kavli Institute for Fundamental Neuroscience University of California San Francisco, School of Medicine, San Francisco, CA, USA
| | - Baris Alten
- Department of Pharmacology, Vanderbilt University, Nashville, TN, USA
- Vanderbilt Brain Institute, Nashville, TN, USA
| | - Magda S. Santos
- Department of Psychiatry, Weill Institute for Neurosciences and Kavli Institute for Fundamental Neuroscience University of California San Francisco, School of Medicine, San Francisco, CA, USA
| | - Ruiji Jiang
- Department of Neurology, Weill Institute for Neurosciences and Institute of Human Genetics. University of California San Francisco, School of Medicine, San Francisco, CA, USA
| | - Brianna Paul
- Department of Neurology, Weill Institute for Neurosciences and Institute of Human Genetics. University of California San Francisco, School of Medicine, San Francisco, CA, USA
| | - Sanam J. Lalani
- Department of Neurology, Weill Institute for Neurosciences and Institute of Human Genetics. University of California San Francisco, School of Medicine, San Francisco, CA, USA
| | - Audrey Cortesi
- Department of Neurology, Weill Institute for Neurosciences and Institute of Human Genetics. University of California San Francisco, School of Medicine, San Francisco, CA, USA
| | - Kendall Parks
- Department of Neurology, Weill Institute for Neurosciences and Institute of Human Genetics. University of California San Francisco, School of Medicine, San Francisco, CA, USA
| | - Nitin Khandelwal
- Department of Neuroscience, UT Southwestern Medical Center, Dallas, TX, USA
| | | | - Malay A. Phoong
- Department of Neuroscience, Pediatric Neuropsychology, Sutter Medical Foundation, Sacramento, CA, USA
| | - Michael Chez
- Neuroscience Medical Group, Sutter Medical Foundation, Sacramento, CA, USA
| | - Heather Fisher
- Department of Genetics, Children’s Medical Center of Texas, Dallas, Texas, USA
| | - Angela E. Scheuerle
- Department of Pediatrics, Division of Genetics and Metabolism, UT Southwestern Medical Center, Dallas, TX, USA
| | - Marwan Shinawi
- Division of Genetics and Genomic Medicine, St. Louis Children’s Hospital, Washington University School of Medicine, St. Louis, MO, USA
| | - Shaun A. Hussain
- Department of Pediatrics, UCLA Mattel Children’s Hospital and Geffen School of Medicine, Los Angeles, CA, USA
| | - Ege T. Kavalali
- Department of Pharmacology, Vanderbilt University, Nashville, TN, USA
- Vanderbilt Brain Institute, Nashville, TN, USA
| | - Elliott H. Sherr
- Department of Neurology, Weill Institute for Neurosciences and Institute of Human Genetics. University of California San Francisco, School of Medicine, San Francisco, CA, USA
| | - Susan M. Voglmaier
- Department of Psychiatry, Weill Institute for Neurosciences and Kavli Institute for Fundamental Neuroscience University of California San Francisco, School of Medicine, San Francisco, CA, USA
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20
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Dhara M, Mantero Martinez M, Makke M, Schwarz Y, Mohrmann R, Bruns D. Synergistic actions of v-SNARE transmembrane domains and membrane-curvature modifying lipids in neurotransmitter release. eLife 2020; 9:e55152. [PMID: 32391794 PMCID: PMC7239655 DOI: 10.7554/elife.55152] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2020] [Accepted: 05/07/2020] [Indexed: 01/01/2023] Open
Abstract
Vesicle fusion is mediated by assembly of SNARE proteins between opposing membranes. While previous work suggested an active role of SNARE transmembrane domains (TMDs) in promoting membrane merger (Dhara et al., 2016), the underlying mechanism remained elusive. Here, we show that naturally-occurring v-SNARE TMD variants differentially regulate fusion pore dynamics in mouse chromaffin cells, indicating TMD flexibility as a mechanistic determinant that facilitates transmitter release from differentially-sized vesicles. Membrane curvature-promoting phospholipids like lysophosphatidylcholine or oleic acid profoundly alter pore expansion and fully rescue the decelerated fusion kinetics of TMD-rigidifying VAMP2 mutants. Thus, v-SNARE TMDs and phospholipids cooperate in supporting membrane curvature at the fusion pore neck. Oppositely, slowing of pore kinetics by the SNARE-regulator complexin-2 withstands the curvature-driven speeding of fusion, indicating that pore evolution is tightly coupled to progressive SNARE complex formation. Collectively, TMD-mediated support of membrane curvature and SNARE force-generated membrane bending promote fusion pore formation and expansion.
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Affiliation(s)
- Madhurima Dhara
- Institute for Physiology, Center of Integrative Physiology and Molecular Medicine, Saarland UniversityHomburgGermany
| | - Maria Mantero Martinez
- Institute for Physiology, Center of Integrative Physiology and Molecular Medicine, Saarland UniversityHomburgGermany
| | - Mazen Makke
- Institute for Physiology, Center of Integrative Physiology and Molecular Medicine, Saarland UniversityHomburgGermany
| | - Yvonne Schwarz
- Institute for Physiology, Center of Integrative Physiology and Molecular Medicine, Saarland UniversityHomburgGermany
| | - Ralf Mohrmann
- Institute for Physiology, Otto-von-Guericke UniversityMagdeburgGermany
| | - Dieter Bruns
- Institute for Physiology, Center of Integrative Physiology and Molecular Medicine, Saarland UniversityHomburgGermany
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21
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Guo LL, Shun XL, He B, Fang PH, Bo P, Zhu Y, Zhang ZW. Cooperation between galanin and insulin in facilitating glucose transporter 4 translocation in adipose cells of diabetic rats. J BIOL REG HOMEOS AG 2019; 33:1327-1335. [PMID: 31487982] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
The glucose transporter 4 (GLUT4) translocation is a vital link of insulin-induced glucose uptake in adipose tissue and skeletal muscle. It is an important topic in anti-diabetic research to explore novel agents to facilitate the role of insulin. The aim of this study was to verify the hypothesis that neuropeptide galanin may enhance insulin-induced GLUT4 translocation to increase glucose uptake in adipose tissue of type 2 diabetic models. Insulin and/or galanin were injected respectively or cooperatively into type 2 diabetic rats once a day for fifteen days. The results showed that administration of galanin significantly enhanced insulin-induced GLUT4 and vesicle-associated membrane protein 2 (VAMP2) translocation, Akt phosphorylation and glucose uptake, but not GLUT4 mRNA and protein expression levels in adipose cells. The beneficial roles of galanin on insulin-induced events may be blocked by MK-2206, an Akt inhibitor, indicating that the Akt phosphorylation is essential for promoting impact of galanin on the insulin-induced events. These results suggest that galanin may benefit insulin-induced GLUT4 and VAMP2 translocation, and subsequent glucose uptake via the activated Akt-VAMP2-GLUT4 pathway in adipose cells. These findings deepen our understanding of the anti-diabetic effect of galanin and its mechanism.
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Affiliation(s)
- L L Guo
- Department of Physical Education, Chuzhou College, Chuzhou, Anhui, China
| | - X L Shun
- Department of Cardiovascular and Intensive Care Unit, First People's Hospital, Yangzhou University, Yangzhou, China
| | - B He
- Department of Endocrinology, Clinical Medical College, Yangzhou University, Yangzhou, Jiangsu, China
| | - P H Fang
- Department of Endocrinology, Clinical Medical College, Yangzhou University, Yangzhou, Jiangsu, China
| | - P Bo
- Department of Endocrinology, Clinical Medical College, Yangzhou University, Yangzhou, Jiangsu, China
| | - Y Zhu
- Department of Endocrinology, Clinical Medical College, Yangzhou University, Yangzhou, Jiangsu, China
| | - Z W Zhang
- Department of Endocrinology, Clinical Medical College, Yangzhou University, Yangzhou, Jiangsu, China
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22
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Golec E, Rosberg R, Zhang E, Renström E, Blom AM, King BC. A cryptic non-GPI-anchored cytosolic isoform of CD59 controls insulin exocytosis in pancreatic β-cells by interaction with SNARE proteins. FASEB J 2019; 33:12425-12434. [PMID: 31412214 DOI: 10.1096/fj.201901007r] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
CD59 is a glycosylphosphatidylinositol (GPI)-anchored cell surface inhibitor of the complement membrane attack complex (MAC). We showed previously that CD59 is highly expressed in pancreatic islets but is down-regulated in rodent models of diabetes. CD59 knockdown but not enzymatic removal of cell surface CD59 led to a loss of glucose-stimulated insulin secretion (GSIS), suggesting that an intracellular pool of CD59 is required. In this current paper, we now report that non-GPI-anchored CD59 is present in the cytoplasm, colocalizes with exocytotic protein vesicle-associated membrane protein 2, and completely rescues GSIS in cells lacking endogenous CD59 expression. The involvement of cytosolic non-GPI-anchored CD59 in GSIS is supported in phosphatidylinositol glycan class A knockout GPI anchor-deficient β-cells, in which GSIS is still CD59 dependent. Furthermore, site-directed mutagenesis demonstrated different structural requirements of CD59 for its 2 functions, MAC inhibition and GSIS. Our results suggest that CD59 is retrotranslocated from the endoplasmic reticulum to the cytosol, a process mediated by recognition of trimmed N-linked oligosaccharides, supported by the partial glycosylation of non-GPI-anchored cytosolic CD59 as well as the failure of N-linked glycosylation site mutant CD59 to reach the cytosol or rescue GSIS. This study thus proposes the previously undescribed existence of non-GPI-anchored cytosolic CD59, which is required for insulin secretion.-Golec, E., Rosberg, R., Zhang, E., Renström, E., Blom, A. M., King, B. C. A cryptic non-GPI-anchored cytosolic isoform of CD59 controls insulin exocytosis in pancreatic β-cells by interaction with SNARE proteins.
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Affiliation(s)
- Ewelina Golec
- Section of Medical Protein Chemistry, Department of Translational Medicine, Lund University, Malmö, Sweden
| | - Rebecca Rosberg
- Section of Medical Protein Chemistry, Department of Translational Medicine, Lund University, Malmö, Sweden
| | - Enming Zhang
- Department of Clinical Sciences Malmö, Lund University Diabetes Centre, Malmö, Sweden
| | - Erik Renström
- Department of Clinical Sciences Malmö, Lund University Diabetes Centre, Malmö, Sweden
| | - Anna M Blom
- Section of Medical Protein Chemistry, Department of Translational Medicine, Lund University, Malmö, Sweden
| | - Ben C King
- Section of Medical Protein Chemistry, Department of Translational Medicine, Lund University, Malmö, Sweden
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23
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Kokotos AC, Harper CB, Marland JRK, Smillie KJ, Cousin MA, Gordon SL. Synaptophysin sustains presynaptic performance by preserving vesicular synaptobrevin-II levels. J Neurochem 2019; 151:28-37. [PMID: 31216055 PMCID: PMC6851701 DOI: 10.1111/jnc.14797] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2019] [Revised: 05/24/2019] [Accepted: 06/01/2019] [Indexed: 01/01/2023]
Abstract
The two most abundant molecules on synaptic vesicles (SVs) are synaptophysin and synaptobrevin‐II (sybII). SybII is essential for SV fusion, whereas synaptophysin is proposed to control the trafficking of sybII after SV fusion and its retrieval during endocytosis. Despite controlling key aspects of sybII packaging into SVs, the absence of synaptophysin results in negligible effects on neurotransmission. We hypothesised that this apparent absence of effect may be because of the abundance of sybII on SVs, with the impact of inefficient sybII retrieval only revealed during periods of repeated SV turnover. To test this hypothesis, we subjected primary cultures of synaptophysin knockout neurons to repeated trains of neuronal activity, while monitoring SV fusion events and levels of vesicular sybII. We identified a significant decrease in both the number of SV fusion events (monitored using the genetically encoded reporter vesicular glutamate transporter‐pHluorin) and vesicular sybII levels (via both immunofluorescence and Western blotting) using this protocol. This revealed that synaptophysin is essential to sustain both parameters during periods of repetitive SV turnover. This was confirmed by the rescue of presynaptic performance by the expression of exogenous synaptophysin. Importantly, the expression of exogenous sybII also fully restored SV fusion events in synaptophysin knockout neurons. The ability of additional copies of sybII to fully rescue presynaptic performance in these knockout neurons suggests that the principal role of synaptophysin is to mediate the efficient retrieval of sybII to sustain neurotransmitter release. ![]()
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Affiliation(s)
- Alexandros C Kokotos
- Centre for Discovery Brain Sciences, Hugh Robson Building, University of Edinburgh, George Square, Edinburgh, Scotland, UK, EH8 9XD.,Muir Maxwell Epilepsy Centre, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh, Scotland, UK, EH8 9XD
| | - Callista B Harper
- Centre for Discovery Brain Sciences, Hugh Robson Building, University of Edinburgh, George Square, Edinburgh, Scotland, UK, EH8 9XD.,Muir Maxwell Epilepsy Centre, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh, Scotland, UK, EH8 9XD.,Simons Initiative for the Developing Brain, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh, Scotland, UK, EH8 9XD
| | - Jamie R K Marland
- Centre for Discovery Brain Sciences, Hugh Robson Building, University of Edinburgh, George Square, Edinburgh, Scotland, UK, EH8 9XD
| | - Karen J Smillie
- Centre for Discovery Brain Sciences, Hugh Robson Building, University of Edinburgh, George Square, Edinburgh, Scotland, UK, EH8 9XD.,Muir Maxwell Epilepsy Centre, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh, Scotland, UK, EH8 9XD
| | - Michael A Cousin
- Centre for Discovery Brain Sciences, Hugh Robson Building, University of Edinburgh, George Square, Edinburgh, Scotland, UK, EH8 9XD.,Muir Maxwell Epilepsy Centre, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh, Scotland, UK, EH8 9XD.,Simons Initiative for the Developing Brain, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh, Scotland, UK, EH8 9XD
| | - Sarah L Gordon
- The Florey Institute of Neuroscience and Mental Health, and Melbourne Dementia Research Centre, The Florey Institute for Neuroscience and Mental Health, The University of Melbourne, Victoria, Australia
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24
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Hart M, Walch-Rückheim B, Krammes L, Kehl T, Rheinheimer S, Tänzer T, Glombitza B, Sester M, Lenhof HP, Keller A, Meese E. miR-34a as hub of T cell regulation networks. J Immunother Cancer 2019; 7:187. [PMID: 31311583 PMCID: PMC6636054 DOI: 10.1186/s40425-019-0670-5] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2019] [Accepted: 07/08/2019] [Indexed: 12/27/2022] Open
Abstract
BACKGROUND Micro(mi)RNAs are increasingly recognized as central regulators of immune cell function. While it has been predicted that miRNAs have multiple targets, the majority of these predictions still await experimental confirmation. Here, miR-34a, a well-known tumor suppressor, is analyzed for targeting genes involved in immune system processes of leucocytes. METHODS Using an in-silico approach, we combined miRNA target prediction with GeneTrail2, a web tool for Multi-omics enrichment analysis, to identify miR-34a target genes, which are involved in the immune system process subcategory of Gene Ontology. RESULTS Out of the 193 predicted target genes in this subcategory we experimentally tested 22 target genes and confirmed binding of miR-34a to 14 target genes including VAMP2, IKBKE, MYH9, MARCH8, KLRK1, CD11A, TRAFD1, CCR1, PYDC1, PRF1, PIK3R2, PIK3CD, AP1B1, and ADAM10 by dual luciferase assays. By transfecting Jurkat, primary CD4+ and CD8+ T cells with miR-34a, we demonstrated that ectopic expression of miR-34a leads to reduced levels of endogenous VAMP2 and CD11A, which are central to the analyzed subcategories. Functional downstream analysis of miR-34a over-expression in activated CD8+ T cells exhibits a distinct decrease of PRF1 secretion. CONCLUSIONS By simultaneous targeting of 14 mRNAs miR-34a acts as major hub of T cell regulatory networks suggesting to utilize miR-34a as target of intervention towards a modulation of the immune responsiveness of T-cells in a broad tumor context.
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Affiliation(s)
- Martin Hart
- Institute of Human Genetics, Saarland University, Building 60, 66421, Homburg, Germany.
| | - Barbara Walch-Rückheim
- Institute of Virology and Center of Human and Molecular Biology, Saarland University, 66421, Homburg, Germany
| | - Lena Krammes
- Institute of Human Genetics, Saarland University, Building 60, 66421, Homburg, Germany
| | - Tim Kehl
- Center for Bioinformatics, Saarland University, 66123, Saarbrücken, Germany
| | - Stefanie Rheinheimer
- Institute of Human Genetics, Saarland University, Building 60, 66421, Homburg, Germany
| | - Tanja Tänzer
- Institute of Virology and Center of Human and Molecular Biology, Saarland University, 66421, Homburg, Germany
| | - Birgit Glombitza
- Institute of Virology and Center of Human and Molecular Biology, Saarland University, 66421, Homburg, Germany
| | - Martina Sester
- Department of Transplant and Infection Immunology, Saarland University, 66421, Homburg, Germany
| | - Hans-Peter Lenhof
- Center for Bioinformatics, Saarland University, 66123, Saarbrücken, Germany
| | - Andreas Keller
- Chair for Clinical Bioinformatics, Saarland University, 66123, Saarbrücken, Germany
| | - Eckart Meese
- Institute of Human Genetics, Saarland University, Building 60, 66421, Homburg, Germany
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25
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Salpietro V, Malintan NT, Llano-Rivas I, Spaeth CG, Efthymiou S, Striano P, Vandrovcova J, Cutrupi MC, Chimenz R, David E, Di Rosa G, Marce-Grau A, Raspall-Chaure M, Martin-Hernandez E, Zara F, Minetti C, Bello OD, De Zorzi R, Fortuna S, Dauber A, Alkhawaja M, Sultan T, Mankad K, Vitobello A, Thomas Q, Mau-Them FT, Faivre L, Martinez-Azorin F, Prada CE, Macaya A, Kullmann DM, Rothman JE, Krishnakumar SS, Houlden H; Deciphering Developmental Disorders Study., SYNAPS Study Group. Mutations in the Neuronal Vesicular SNARE VAMP2 Affect Synaptic Membrane Fusion and Impair Human Neurodevelopment. Am J Hum Genet 2019; 104:721-30. [PMID: 30929742 DOI: 10.1016/j.ajhg.2019.02.016] [Citation(s) in RCA: 72] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2018] [Accepted: 02/13/2019] [Indexed: 01/21/2023] Open
Abstract
VAMP2 encodes the vesicular SNARE protein VAMP2 (also called synaptobrevin-2). Together with its partners syntaxin-1A and synaptosomal-associated protein 25 (SNAP25), VAMP2 mediates fusion of synaptic vesicles to release neurotransmitters. VAMP2 is essential for vesicular exocytosis and activity-dependent neurotransmitter release. Here, we report five heterozygous de novo mutations in VAMP2 in unrelated individuals presenting with a neurodevelopmental disorder characterized by axial hypotonia (which had been present since birth), intellectual disability, and autistic features. In total, we identified two single-amino-acid deletions and three non-synonymous variants affecting conserved residues within the C terminus of the VAMP2 SNARE motif. Affected individuals carrying de novo non-synonymous variants involving the C-terminal region presented a more severe phenotype with additional neurological features, including central visual impairment, hyperkinetic movement disorder, and epilepsy or electroencephalography abnormalities. Reconstituted fusion involving a lipid-mixing assay indicated impairment in vesicle fusion as one of the possible associated disease mechanisms. The genetic synaptopathy caused by VAMP2 de novo mutations highlights the key roles of this gene in human brain development and function.
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26
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Li F, Pincet F. SNAREpin Assembly: Kinetic and Thermodynamic Approaches. Methods Mol Biol 2019; 1860:71-93. [PMID: 30317499 DOI: 10.1007/978-1-4939-8760-3_5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
Abstract
Proteins constantly interact and often form molecular complexes. The dynamics of most biological processes strongly rely on the kinetics and thermodynamics of assembly and disassembly of these complexes. Consequently an accurate characterization of these kinetics and thermodynamics that underlie them provides key information to better understand these processes. Here, we present two efficient techniques to quantify the assembly and disassembly of protein complexes: isothermal titration calorimetry and fluorescence anisotropy. As an example we focus on the formation of SNAREpins and also present how to prepare SNARE proteins to use in these experimental setups. We then show how to use these techniques to determine the critical factors that activate assembly kinetics.
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27
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Sheehan P, Zhu M, Beskow A, Vollmer C, Waites CL. Activity-Dependent Degradation of Synaptic Vesicle Proteins Requires Rab35 and the ESCRT Pathway. J Neurosci 2016; 36:8668-86. [PMID: 27535913 DOI: 10.1523/JNEUROSCI.0725-16.2016] [Citation(s) in RCA: 80] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2016] [Accepted: 06/29/2016] [Indexed: 02/06/2023] Open
Abstract
UNLABELLED Synaptic vesicle (SV) pools must maintain a functional repertoire of proteins to efficiently release neurotransmitter. The accumulation of old or damaged proteins on SV membranes is linked to synaptic dysfunction and neurodegeneration. However, despite the importance of SV protein turnover for neuronal health, the molecular mechanisms underlying this process are largely unknown. Here, we have used dissociated rat hippocampal neurons to investigate the pathway for SV protein degradation. We find that neuronal activity drives the degradation of a subset of SV proteins and that the endosomal sorting complex required for transport (ESCRT) machinery and SV-associated GTPase Rab35 are key elements of this use-dependent degradative pathway. Specifically, neuronal activity induces Rab35 activation and binding to the ESCRT-0 protein Hrs, which we have identified as a novel Rab35 effector. These actions recruit the downstream ESCRT machinery to SV pools, thereby initiating SV protein degradation via the ESCRT pathway. Our findings show that the Rab35/ESCRT pathway facilitates the activity-dependent removal of specific proteins from SV pools, thereby maintaining presynaptic protein homeostasis. SIGNIFICANCE STATEMENT Synaptic transmission is mediated by the release of chemical neurotransmitters from synaptic vesicles (SVs). This tightly regulated process requires a functional pool of SVs, necessitating cellular mechanisms for removing old or damaged proteins that could impair SV cycling. Here, we show that a subset of SV proteins is degraded in an activity-dependent manner and that key steps in this degradative pathway are the activation of the small GTPase Rab35 and the subsequent recruitment of the endosomal sorting complex required for transport (ESCRT) machinery to SV pools. Further, we demonstrate that ESCRT-0 component Hrs is an effector of Rab35, thus providing novel mechanistic insight into the coupling of neuronal activity with SV protein degradation and the maintenance of functional SV pools.
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28
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Zhang Z, Fang P, Guo L, He B, Shi M, Zhu Y, Bo P. Akt2-Dependent Beneficial Effect of Galanin on Insulin-Induced Glucose Uptake in Adipocytes of Diabetic Rats. Cell Physiol Biochem 2017; 41:1777-1787. [PMID: 28365702 DOI: 10.1159/000471870] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2016] [Accepted: 02/02/2017] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND/AIMS Glucose uptake occurs via the activation of an insulin-signaling cascade, resulting in the translocation of glucose transporter 4 (GLUT4) to the plasma membrane of adipocytes and myocytes. Recent research found that galanin could boost insulin-induced glucose uptake. This study aimed to explore whether activation of Akt2 mediates the beneficial effects of galanin on insulin-induced glucose uptake in the adipocytes of diabetic rats. METHOD In this experiment, insulin, galanin and MK-2206, an Akt inhibitor, were injected individually or in combination into diabetic rats once a day for ten days. Then, glucose uptake and pAkt2 and its downstream proteins were examined in adipocytes. RESULTS Administration of galanin significantly enhanced insulin-induced 2-Deoxy-D-[3H]glucose uptake; GLUT4 and vesicle-associated membrane protein 2 contents in plasma membranes; and pAkt2Thr308/Ser473 and Akt2 mRNA expression levels in adipocytes. In addition, Akt2 downstream proteins including phosphorylated AS160 were increased, but the levels of phosphorylated forkhead box O1 and glycogen synthase kinase-3β were reduced. Treatment with MK-2206 may block the beneficial effects of galanin on these insulin-induced events. CONCLUSIONS The results of this study suggest that phosphorylation of Akt2 mediates the beneficial effects of galanin on insulin-induced glucose uptake in the adipocytes of diabetic rats.
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Affiliation(s)
- Zhenwen Zhang
- Department of Endocrinology, Clinical Medical College, Yangzhou, China
| | - Penghua Fang
- Key Rresearch Institute of Gerontology, Medical College, Yangzhou University, Yangzhou, China.,Department of Physiology, School of Hanlin, Nanjing University of Chinese Medicine, Taizhou, China
| | - Lili Guo
- Key Rresearch Institute of Gerontology, Medical College, Yangzhou University, Yangzhou, China
| | - Biao He
- Key Rresearch Institute of Gerontology, Medical College, Yangzhou University, Yangzhou, China
| | - Mingyi Shi
- Key Rresearch Institute of Gerontology, Medical College, Yangzhou University, Yangzhou, China
| | - Yan Zhu
- Department of Endocrinology, Clinical Medical College, Yangzhou, China
| | - Ping Bo
- Department of Endocrinology, Clinical Medical College, Yangzhou, China.,Key Rresearch Institute of Gerontology, Medical College, Yangzhou University, Yangzhou, China
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29
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Vallortigara J, Whitfield D, Quelch W, Alghamdi A, Howlett D, Hortobágyi T, Johnson M, Attems J, O'Brien JT, Thomas A, Ballard CG, Aarsland D, Francis PT. Decreased Levels of VAMP2 and Monomeric Alpha-Synuclein Correlate with Duration of Dementia. J Alzheimers Dis 2016; 50:101-10. [PMID: 26639969 DOI: 10.3233/jad-150707] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Alpha-synuclein (α-syn) aggregations are the key pathological hallmark of dementia with Lewy bodies (DLB) and Parkinson's disease dementia (PDD), but are also frequently present in Alzheimer's disease (AD). Much remains unknown about the role of α-syn in the synapse and the wider role of synaptic dysfunction in these dementias. Changes in concentrations of key 'SNAP (Soluble N-ethylmaleimide Sensitive Factor Attachment Protein) Receptor' (SNARE) proteins as a consequence of alterations in the aggregation state of α-syn may contribute to synaptic dysfunction in patients with DLB, PDD, and AD and result in impaired cognition. We have studied a large cohort (n = 130) of autopsy confirmed DLB, PDD, AD, and control brains. Using semi-quantitative western blotting, we have demonstrated significant changes across the diagnostic groups of DLB, PDD, and AD in the SNARE and vesicle proteins syntaxin, Munc18, VAMP2, and monomeric α-syn in the prefrontal cortex, with a significant reduction of Munc18 in AD patients (p < 0.001). This correlated to the final MMSE score before death (p = 0.016). We also identified a significant negative correlation between the duration of dementia and the levels of the binding partners VAMP2 (p = 0.0004) and monomeric α-syn (p = 0.0002). Our findings may indicate that an upregulation of SNARE complex related proteins occurs in the early stages of disease as an attempt at compensating for failing synapses, prior to widespread deposition of pathological α-syn.
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Affiliation(s)
- Julie Vallortigara
- Wolfson Centre for Age-Related Diseases, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK
| | - David Whitfield
- Wolfson Centre for Age-Related Diseases, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK
| | - William Quelch
- Wolfson Centre for Age-Related Diseases, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK
| | - Amani Alghamdi
- Wolfson Centre for Age-Related Diseases, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK
| | - David Howlett
- Wolfson Centre for Age-Related Diseases, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK
| | - Tibor Hortobágyi
- Division of Neuropathology, Institute of Pathology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Mary Johnson
- Institute of Neuroscience, Newcastle University, CAV, Newcastle upon Tyne, UK
| | - Johannes Attems
- Institute of Neuroscience, Newcastle University, CAV, Newcastle upon Tyne, UK
| | - John T O'Brien
- Institute of Neuroscience, Newcastle University, CAV, Newcastle upon Tyne, UK.,Department of Psychiatry, University of Cambridge, Cambridge, UK
| | - Alan Thomas
- Institute of Neuroscience, Newcastle University, CAV, Newcastle upon Tyne, UK
| | - Clive G Ballard
- Wolfson Centre for Age-Related Diseases, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK
| | - Dag Aarsland
- Department of Neurobiology, Ward Sciences and Society, Karolinska Institute, Stockholm, Sweden.,Centre for Age-Related Medicine, Stavanger University Hospital, Stavanger, Norway
| | - Paul T Francis
- Wolfson Centre for Age-Related Diseases, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK
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Baghel R, Grover S, Kaur H, Jajodia A, Parween S, Sinha J, Srivastava A, Srivastava AK, Bala K, Chandna P, Kushwaha S, Agarwal R, Kukreti R. Synergistic association of STX1A and VAMP2 with cryptogenic epilepsy in North Indian population. Brain Behav 2016; 6:e00490. [PMID: 27458546 PMCID: PMC4951625 DOI: 10.1002/brb3.490] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/04/2015] [Revised: 03/05/2016] [Accepted: 03/29/2016] [Indexed: 12/18/2022] Open
Abstract
INTRODUCTION "Common epilepsies", merely explored for genetics are the most frequent, nonfamilial, sporadic cases in hospitals. Because of their much debated molecular pathology, there is a need to focus on other neuronal pathways including the existing ion channels. METHODS For this study, a total of 214 epilepsy cases of North Indian ethnicity comprising 59.81% generalized, 40.19% focal seizures, and based on epilepsy types, 17.29% idiopathic, 37.38% cryptogenic, and 45.33% symptomatic were enrolled. Additionally, 170 unrelated healthy individuals were also enrolled. Here, we hypothesize the involvement of epilepsy pathophysiology genes, that is, synaptic vesicle cycle, SVC genes (presynapse), ion channels and their functionally related genes (postsynapse). An interactive analysis was initially performed in SVC genes using multifactor dimensionality reduction (MDR). Further, in order to understand the influence of ion channels and their functionally related genes, their interaction analysis with SVC genes was also performed. RESULTS A significant interactive two-locus model of STX1A_rs4363087|VAMP2_rs2278637 (presynaptic genes) was observed among SVC variants in all epilepsy cases (P 1000-value = 0.054; CVC = 9/10; OR = 2.86, 95%CI = 1.88-4.35). Further, subgroup analysis revealed stronger interaction for the same model in cryptogenic epilepsy patients only (P 1000-value = 0.012; CVC = 10/10; OR = 4.59, 95%CI = 2.57-8.22). However, interactive analysis of presynaptic and postsynaptic genes did not show any significant association. CONCLUSIONS Significant synergistic interaction of SVC genes revealed the possible functional relatedness of presynapse with pathophysiology of cryptogenic epilepsy. Further, to establish the clinical utility of the results, replication in a large and similar phenotypic group of patients is warranted.
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Affiliation(s)
- Ruchi Baghel
- Council of Scientific and Industrial Research (CSIR) Institute of Genomics and Integrative Biology (IGIB) Mall Road Delhi 110 007 India
| | - Sandeep Grover
- Council of Scientific and Industrial Research (CSIR) Institute of Genomics and Integrative Biology (IGIB) Mall Road Delhi 110 007 India; Division of Pneumonology-Immunology Department of Paediatrics Charité University Medical Centre Berlin Germany
| | - Harpreet Kaur
- Council of Scientific and Industrial Research (CSIR) Institute of Genomics and Integrative Biology (IGIB) Mall Road Delhi 110 007 India
| | - Ajay Jajodia
- Council of Scientific and Industrial Research (CSIR) Institute of Genomics and Integrative Biology (IGIB) Mall Road Delhi 110 007 India
| | - Shama Parween
- Council of Scientific and Industrial Research (CSIR) Institute of Genomics and Integrative Biology (IGIB) Mall Road Delhi 110 007 India
| | - Juhi Sinha
- Council of Scientific and Industrial Research (CSIR) Institute of Genomics and Integrative Biology (IGIB) Mall Road Delhi 110 007 India
| | - Ankit Srivastava
- Council of Scientific and Industrial Research (CSIR) Institute of Genomics and Integrative Biology (IGIB) Mall Road Delhi 110 007 India
| | - Achal Kumar Srivastava
- Neurology Department Neuroscience Centre All India Institute of Medical Sciences (AIIMS) New Delhi India
| | - Kiran Bala
- Institute of Human Behavior & Allied Sciences (IHBAS) Dilshad Garden Delhi 110 095 India
| | | | - Suman Kushwaha
- Institute of Human Behavior & Allied Sciences (IHBAS) Dilshad Garden Delhi 110 095 India
| | - Rachna Agarwal
- Institute of Human Behavior & Allied Sciences (IHBAS) Dilshad Garden Delhi 110 095 India
| | - Ritushree Kukreti
- Council of Scientific and Industrial Research (CSIR) Institute of Genomics and Integrative Biology (IGIB) Mall Road Delhi 110 007 India
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Bhat R, Bhattacharyya PK, Ratech H. An Immunohistochemical Survey of SNARE Proteins Shows Distinct Patterns of Expression in Hematolymphoid Neoplasia. Am J Clin Pathol 2016; 145:604-16. [PMID: 27247366 DOI: 10.1093/ajcp/aqw022] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
OBJECTIVES Five proteins from the soluble N-ethylmaleimide-sensitive factor activating protein receptor (SNARE) complex family were studied in normal hematopoietic cells in bone marrow; normal lymphocytes at different stages of maturation and differentiation in bone marrow, thymus, tonsil, and lymph node; malignant lymphomas; and leukemias. METHODS Sixty-eight reactive and 380 hematopoietic and lymphoid neoplasms were immunohistochemically stained for syntaxin 7 (STX7), vesicle-associated membrane proteins (VAMP2, VAMP7, VAMP8), and synaptosomal-associated protein 23 (SNAP23). RESULTS STX7 has potential for being a useful marker for distinguishing between normal B precursors (hematogones) vs B lymphoblasts, as well as between the "popcorn" cells of nodular lymphocyte-predominant Hodgkin lymphoma vs the Reed-Sternberg cells of classic Hodgkin lymphoma or the B cells of T-cell, histiocyte-rich B-cell lymphoma. VAMP2 is uniquely expressed by both reactive and malignant plasma cells, in contrast to B-cell non-Hodgkin lymphoma. There is differential expression of SNARE proteins in normal and neoplastic lymphoid tissue depending on lymphocyte maturation stage. CONCLUSIONS Differential SNARE protein expression in the lymphoid system may have potential use in diagnosis and may offer clues to lymphoma biology. VAMP2 is a promising new plasma cell marker.
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Affiliation(s)
- Rekha Bhat
- From the Department of Pathology, Montefiore Medical Center/Albert Einstein College of Medicine, Bronx, NY
| | | | - Howard Ratech
- From the Department of Pathology, Montefiore Medical Center/Albert Einstein College of Medicine, Bronx, NY
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Ropert N, Jalil A, Li D. Expression and cellular function of vSNARE proteins in brain astrocytes. Neuroscience 2015; 323:76-83. [PMID: 26518463 DOI: 10.1016/j.neuroscience.2015.10.036] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2015] [Revised: 10/07/2015] [Accepted: 10/21/2015] [Indexed: 12/27/2022]
Abstract
Gray matter protoplasmic astrocytes, a major type of glial cell in the mammalian brain, extend thin processes ensheathing neuronal synaptic terminals. Albeit electrically silent, astrocytes respond to neuronal activity with Ca(2+) signals that trigger the release of gliotransmitters, such as glutamate, d-serine, and ATP, which modulate synaptic transmission. It has been suggested that the astrocytic processes, together with neuronal pre- and post-synaptic elements, constitute a tripartite synapse, and that astrocytes actively regulate information processing. Astrocytic vesicles expressing VAMP2 and VAMP3 vesicular SNARE (vSNARE) proteins have been suggested to be a key feature of the tripartite synapse and mediate gliotransmitter release through Ca(2+)-regulated exocytosis. However, the concept of exocytotic release of gliotransmitters by astrocytes has been challenged. Here we review studies investigating the expression profile of VAMP2 and VAMP3 vSNARE proteins in rodent astrocytes, and the functional implication of VAMP2/VAMP3 vesicles in astrocyte signaling. We also discuss our recent data suggesting that astrocytic VAMP3 vesicles regulate the trafficking of glutamate transporters at the plasma membrane and glutamate uptake. A better understanding of the functional consequences of the astrocytic vSNARE vesicles on glutamate signaling, neuronal excitability and plasticity, will require the development of new strategies to selectively interrogate the astrocytic vesicles trafficking in vivo.
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Affiliation(s)
- N Ropert
- Brain Physiology Laboratory, CNRS UMR8118, Paris F-75006, France; Fédération de Recherche en Neurosciences, FR 3636, Université Paris Descartes, 45 rue des Saints Pères, Paris F-75006, France; Sorbonne Paris Cité, 190, avenue de France, Paris F-75013, France
| | - A Jalil
- Brain Physiology Laboratory, CNRS UMR8118, Paris F-75006, France; Fédération de Recherche en Neurosciences, FR 3636, Université Paris Descartes, 45 rue des Saints Pères, Paris F-75006, France; Sorbonne Paris Cité, 190, avenue de France, Paris F-75013, France
| | - D Li
- Brain Physiology Laboratory, CNRS UMR8118, Paris F-75006, France; Fédération de Recherche en Neurosciences, FR 3636, Université Paris Descartes, 45 rue des Saints Pères, Paris F-75006, France; Sorbonne Paris Cité, 190, avenue de France, Paris F-75013, France.
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Kubo K, Kobayashi M, Nozaki S, Yagi C, Hatsuzawa K, Katoh Y, Shin HW, Takahashi S, Nakayama K. SNAP23/25 and VAMP2 mediate exocytic event of transferrin receptor-containing recycling vesicles. Biol Open 2015; 4:910-20. [PMID: 26092867 PMCID: PMC4571095 DOI: 10.1242/bio.012146] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
We recently showed that Rab11 is involved not only in formation of recycling vesicles containing the transferrin (Tfn)–transferrin receptor (TfnR) complex at perinuclear recycling endosomes but also in tethering of recycling vesicles to the plasma membrane (PM) in concert with the exocyst tethering complex. We here aimed at identifying SNARE proteins responsible for fusion of Tfn–TfnR-containing recycling vesicles with the PM, downstream of the exocyst. We showed that exocyst subunits, Sec6 and Sec8, can interact with SNAP23 and SNAP25, both of which are PM-localizing Qbc-SNAREs, and that depletion of SNAP23 and/or SNAP25 in HeLa cells suppresses fusion of Tfn–TfnR-containing vesicles with the PM, leading to accumulation of the vesicles at the cell periphery. We also found that VAMP2, an R-SNARE, is colocalized with endocytosed Tfn on punctate endosomal structures, and that its depletion in HeLa cells suppresses recycling vesicle exocytosis. These observations indicate that fusion of recycling vesicles with the PM downstream of the exocyst is mediated by SNAP23/25 and VAMP2, and provide novel insight into non-neuronal roles of VAMP2 and SNAP25.
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Affiliation(s)
- Keiji Kubo
- Graduate School of Pharmaceutical Sciences, Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan
| | - Minako Kobayashi
- Graduate School of Pharmaceutical Sciences, Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan
| | - Shohei Nozaki
- Graduate School of Pharmaceutical Sciences, Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan
| | - Chikako Yagi
- Graduate School of Pharmaceutical Sciences, Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan
| | - Kiyotaka Hatsuzawa
- Division of Molecular Biology, Tottori University School of Life Science, Yonago, Tottori 683-8503, Japan
| | - Yohei Katoh
- Graduate School of Pharmaceutical Sciences, Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan
| | - Hye-Won Shin
- Graduate School of Pharmaceutical Sciences, Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan
| | - Senye Takahashi
- Graduate School of Pharmaceutical Sciences, Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan
| | - Kazuhisa Nakayama
- Graduate School of Pharmaceutical Sciences, Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan
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Renard HF, Garcia-Castillo MD, Chambon V, Lamaze C, Johannes L. Shiga toxin stimulates clathrin-independent endocytosis of the VAMP2, VAMP3 and VAMP8 SNARE proteins. J Cell Sci 2015; 128:2891-902. [PMID: 26071526 DOI: 10.1242/jcs.171116] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2015] [Accepted: 06/08/2015] [Indexed: 01/08/2023] Open
Abstract
Endocytosis is an essential cellular process that is often hijacked by pathogens and pathogenic products. Endocytic processes can be classified into two broad categories, those that are dependent on clathrin and those that are not. The SNARE proteins VAMP2, VAMP3 and VAMP8 are internalized in a clathrin-dependent manner. However, the full scope of their endocytic behavior has not yet been elucidated. Here, we found that VAMP2, VAMP3 and VAMP8 are localized on plasma membrane invaginations and very early uptake structures that are induced by the bacterial Shiga toxin, which enters cells by clathrin-independent endocytosis. We show that toxin trafficking into cells and cell intoxication rely on these SNARE proteins. Of note, the cellular uptake of VAMP3 is increased in the presence of Shiga toxin, even when clathrin-dependent endocytosis is blocked. We therefore conclude that VAMP2, VAMP3 and VAMP8 are removed from the plasma membrane by non-clathrin-mediated pathways, in addition to by clathrin-dependent uptake. Moreover, our study identifies these SNARE proteins as the first transmembrane trafficking factors that functionally associate at the plasma membrane with the toxin-driven clathrin-independent invaginations during the uptake process.
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Affiliation(s)
- Henri-François Renard
- Institut Curie - Centre de Recherche, Endocytic Trafficking and Therapeutic Delivery Group, 26 rue d'Ulm, Paris 75248, Cedex 05, France CNRS UMR3666, Paris 75005, France INSERM U1143, Paris 75005, France
| | - Maria Daniela Garcia-Castillo
- Institut Curie - Centre de Recherche, Endocytic Trafficking and Therapeutic Delivery Group, 26 rue d'Ulm, Paris 75248, Cedex 05, France CNRS UMR3666, Paris 75005, France INSERM U1143, Paris 75005, France
| | - Valérie Chambon
- Institut Curie - Centre de Recherche, Endocytic Trafficking and Therapeutic Delivery Group, 26 rue d'Ulm, Paris 75248, Cedex 05, France CNRS UMR3666, Paris 75005, France INSERM U1143, Paris 75005, France
| | - Christophe Lamaze
- CNRS UMR3666, Paris 75005, France INSERM U1143, Paris 75005, France Institut Curie - Centre de Recherche, Membrane Dynamics and Mechanics of Intracellular Signaling Group, 26 rue d'Ulm, Paris 75248, Cedex 05, France
| | - Ludger Johannes
- Institut Curie - Centre de Recherche, Endocytic Trafficking and Therapeutic Delivery Group, 26 rue d'Ulm, Paris 75248, Cedex 05, France CNRS UMR3666, Paris 75005, France INSERM U1143, Paris 75005, France
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Glazova MV, Nikitina LS, Hudik KA, Kirillova OD, Dorofeeva NA, Korotkov AA, Chernigovskaya EV. Inhibition of ERK1/2 signaling prevents epileptiform behavior in rats prone to audiogenic seizures. J Neurochem 2014; 132:218-29. [PMID: 25351927 DOI: 10.1111/jnc.12982] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2014] [Revised: 10/14/2014] [Accepted: 10/22/2014] [Indexed: 01/24/2023]
Abstract
It has recently been proposed that extracellular signal-regulated kinases 1 and 2 (ERK1/2) are one of the factors mediating seizure development. We hypothesized that inhibition of ERK1/2 activity could prevent audiogenic seizures by altering GABA and glutamate release mechanisms. Krushinsky-Molodkina rats, genetically prone to audiogenic seizure, were recruited in the experiments. Animals were i.p. injected with an inhibitor of ERK1/2 SL 327 at different doses 60 min before audio stimulation. We demonstrated for the first time that inhibition of ERK1/2 activity by SL 327 injections prevented seizure behavior and this effect was dose-dependent and correlated with ERK1/2 activity. The obtained data also demonstrated unchanged levels of GABA production, and an increase in the level of vesicular glutamate transporter 2. The study of exocytosis protein expression showed that SL 327 treatment leads to downregulation of vesicle-associated membrane protein 2 and synapsin I, and accumulation of synaptosomal-associated protein 25 (SNAP-25). The obtained data indicate that the inhibition of ERK1/2 blocks seizure behavior presumably by altering the exocytosis machinery, and identifies ERK1/2 as a potential target for the development of new strategies for seizure treatment. Extracellular signal-regulated kinases 1 and 2 (ERK1/2) are one of the factors mediating seizure development. Here we report that inhibition of ERK1/2 by SL 327 prevented seizure behavior and this effect was dose-dependent and correlated with ERK1/2 activity. Accumulation of VGLUT2 was associated with differential changing of synaptic proteins VAMP2, SNAP-25 and synapsin I. The obtained data indicate that the inhibition of ERK1/2 alters neurotransmitter release by changing the exocytosis machinery, thus preventing seizures.
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Affiliation(s)
- Margarita V Glazova
- Sechenov Institute of Evolutionary Physiology and Biochemistry, Russian Academy of Sciences, Saint-Petersburg, Russia
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Bröer S, Zolkowska D, Gernert M, Rogawski MA. Proconvulsant actions of intrahippocampal botulinum neurotoxin B in the rat. Neuroscience 2013; 252:253-61. [PMID: 23906638 PMCID: PMC4530632 DOI: 10.1016/j.neuroscience.2013.07.050] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2013] [Revised: 07/22/2013] [Accepted: 07/22/2013] [Indexed: 01/21/2023]
Abstract
Botulinum neurotoxins (BoNTs) may affect the excitability of brain circuits by inhibiting neurotransmitter release at central synapses. There is evidence that local delivery of BoNT serotypes A and E, which target SNAP-25, a component of the release machinery specific to excitatory synapses, can inhibit seizure generation. BoNT serotype B (BoNT/B) targets VAMP2, which is expressed in both excitatory and inhibitory terminals. Here we assessed the effects of unilateral intrahippocampal infusion of BoNT/B in the rat on intravenous pentylenetetrazol (PTZ) seizure thresholds, and on the expression of spontaneous behavioral and electrographic seizures. Infusion of BoNT/B (500 and 1,000 unit) by convection-enhanced delivery caused a reduction in myoclonic twitch and clonic seizure thresholds in response to intravenous PTZ beginning about 6 days after the infusion. Handling-evoked and spontaneous convulsive seizures were observed in many BoNT/B-treated animals but not in vehicle-treated controls. Spontaneous electrographic seizure discharges were recorded in the dentate gyrus of animals that received local BoNT/B infusion. In addition, there was an increased frequency of interictal epileptiform spikes and sharp waves at the same recording site. BoNT/B-treated animals also exhibited tactile hyperresponsivity in comparison with vehicle-treated controls. This is the first demonstration that BoNT/B causes a delayed proconvulsant action when infused into the hippocampus. Local infusion of BoNT/B could be useful as a focal epilepsy model.
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Affiliation(s)
- Sonja Bröer
- Department of Neurology, School of Medicine, University of California, Davis, Sacramento, California, USA
| | - Dorota Zolkowska
- Department of Neurology, School of Medicine, University of California, Davis, Sacramento, California, USA
| | - Manuela Gernert
- Department of Pharmacology, Toxicology, and Pharmacy, University of Veterinary Medicine Hannover and Center for Systems Neuroscience, Hannover, Germany
| | - Michael A. Rogawski
- Department of Neurology, School of Medicine, University of California, Davis, Sacramento, California, USA
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Wang D, Krilich J, Pellett S, Baudys J, Tepp WH, Barr JR, Johnson EA, Kalb SR. Comparison of the catalytic properties of the botulinum neurotoxin subtypes A1 and A5. Biochim Biophys Acta 2013; 1834:2722-8. [PMID: 24096023 DOI: 10.1016/j.bbapap.2013.09.007] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/07/2013] [Revised: 09/12/2013] [Accepted: 09/16/2013] [Indexed: 11/22/2022]
Abstract
Clostridium botulinum neurotoxins (BoNTs) cause the life-threatening disease botulism through the inhibition of neurotransmitter release by cleaving essential SNARE proteins. There are seven serologically distinctive types of BoNTs and many subtypes within a serotype have been identified. BoNT/A5 is a recently discovered subtype of type A botulinum neurotoxin which possesses a very high degree of sequence similarity and identity to the well-studied A1 subtype. In the present study, we examined the endopeptidase activity of these two BoNT/A subtypes and our results revealed significant differences in substrate binding and cleavage efficiency between subtype A5 and A1. Distinctive hydrolysis efficiency was observed between the two toxins during cleavage of the native substrate SNAP-25 versus a shortened peptide mimic. N-terminal truncation studies demonstrated that a key region of the SNAP-25, including the amino acid residues at 151 through 154 located in the remote binding region of the substrate, contributed to the differential catalytic properties between A1 and A5. Elevated binding affinity of the peptide substrate resulted from including these important residues and enhanced BoNT/A5's hydrolysis efficiency. In addition, mutations of these amino acid residues affect the proteolytic performance of the two toxins in different ways. This study provides a better understanding of the biological activity of these toxins, their performance characteristics in the Endopep-MS assay to detect BoNT in clinical samples and foods, and is useful for the development of peptide substrates.
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Chung WY, Park HW, Han JW, Lee MG, Kim JY. WNK4 inhibits plasma membrane targeting of NCC through regulation of syntaxin13 SNARE formation. Cell Signal 2013; 25:2469-77. [PMID: 23993962 DOI: 10.1016/j.cellsig.2013.08.006] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2013] [Accepted: 08/23/2013] [Indexed: 01/27/2023]
Abstract
WNK4, a serine/threonine kinase, plays a critical role in the expression of membrane proteins in the cell surface; however, the underlying mechanism of WNK4 is not clear. Here, we demonstrate that WNK4 inhibits the fusion of plasma membrane delivering vesicle with sorting/recycling endosome through disrupting SNARE formation of syntaxin13, an endosomal t-SNARE and VAMP2, the v-SNARE in plasma membrane delivering vesicle. Their interaction and co-localization were enhanced by hyperosmotic stimulation which is known for WNK4 activation. The kinase domain of WNK4 interacts with the transmembrane domain (TM) of syntaxin13 and this interaction was abolished when the TM was replaced with that of syntaxin16. Interestingly, cell fractionation using sucrose gradients revealed that WNK4 inhibited the formation of the syntaxin13/VAMP2 SNARE complex in the endosomal compartment, but not syntaxin16/VAMP2 or syntaxin13/VAMP7. Syntaxin13 was not phosphorylated by WNK4 and WNK4KI also showed the same binding strength and similar inhibitory regulation on SNARE formation of syntaxin13. Physiological relevance of this mechanism was proved with the expression of NCC (Na(+) C1(-) co-transporter) in the cell surface. The inhibiting activity of WNK4 on surface expression of NCC was abolished by syntaxin13 siRNA transfection. These results suggest that WNK4 attenuates PM targeting of NCC proteins through regulation of syntaxin13 SNARE complex formation with VAMP2 in recycling and sorting endosome.
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Affiliation(s)
- Woo Young Chung
- Department of Pharmacology and Brain Korea 21 Project for Medical Science, Yonsei University College of Medicine, Seoul 120-752, Republic of Korea
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Guo J, Pan X, Zhao Y, Chen S. Engineering Clostridia Neurotoxins with elevated catalytic activity. Toxicon 2013; 74:158-66. [PMID: 23994593 DOI: 10.1016/j.toxicon.2013.08.055] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2013] [Revised: 08/18/2013] [Accepted: 08/21/2013] [Indexed: 11/30/2022]
Abstract
BoNT/B and TeNT cleave substrate VAMP2 at the same scissile bond, yet these two toxins showed different efficiency on substrate hydrolysis and had different requirements for the recognition of P2' site of VAMP2, E(78). These differences may be due to their different composition of their substrate recognition pockets in the active site. Swapping of LC/T S1' pocket residue, L(230), with the corresponding isoleucine in LC/B increased LC/T activity by ∼25 fold, while swapping of LC/B S1' pocket residue, S(201), with the corresponding proline in LC/T increased LC/B activity by ∼10 fold. Optimization of both S1 and S1' pocket residues of LC/T, LC/T (K(168)E, L(230)I) elevated LC/T activity by more than 100-fold. The highly active LC/T derivative engineered in this study has the potential to be used as a more effective tool to study mechanisms of exocytosis in central neuron. The LC/B derivative with elevated activity has the potential to be developed into novel therapy to minimize the impact of immunoresistance during BoNT/B therapy.
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Affiliation(s)
- Jiubiao Guo
- Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong Special Administrative Region
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Flašker A, Jorgačevski J, Calejo AI, Kreft M, Zorec R. Vesicle size determines unitary exocytic properties and their sensitivity to sphingosine. Mol Cell Endocrinol 2013; 376:136-47. [PMID: 23791846 DOI: 10.1016/j.mce.2013.06.012] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/20/2013] [Revised: 06/11/2013] [Accepted: 06/11/2013] [Indexed: 11/23/2022]
Abstract
Neuroendocrine cells contain small and large vesicles, but the functional significance of vesicle diameter is unclear. We studied unitary exocytic events of prolactin-containing vesicles in lactotrophs by monitoring discrete steps in membrane capacitance. In the presence of sphingosine, which recruits VAMP2 for SNARE complex formation, the frequency of transient and full fusion events increased. Vesicles with larger diameters proceeded to full fusion, but smaller vesicles remained entrapped in transient exocytosis. The diameter of vesicle dense cores released by full fusion exocytosis into the extracellular space was larger than the diameter of the remaining intracellular vesicles beneath the plasma membrane. Labeling with prolactin- and VAMP2-antibodies revealed a correlation between the diameters of colocalized prolactin- and VAMP2-positive structures. It is proposed that sphingosine-mediated facilitation of regulated exocytosis is not only related to the number of SNARE complexes per vesicle but also depends on the vesicle size, which may determine the transition between transient and full fusion exocytosis.
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Affiliation(s)
- Ajda Flašker
- Laboratory of Neuroendocrinology-Molecular Cell Physiology, Faculty of Medicine, University of Ljubljana, Zaloška 4, 1000 Ljubljana, Slovenia.
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Matteucci A, Gaddini L, Macchia G, Varano M, Petrucci TC, Macioce P, Malchiodi-Albedi F, Ceccarini M. Developmental expression of dysbindin in Muller cells of rat retina. Exp Eye Res 2013; 116:1-8. [PMID: 23954924 DOI: 10.1016/j.exer.2013.08.006] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2013] [Revised: 07/30/2013] [Accepted: 08/06/2013] [Indexed: 01/09/2023]
Abstract
Dysbindin, the product of the DTNBP1 gene, was identified by yeast two hybrid assay as a binding partner of dystrobrevin, a cytosolic component of the dystrophin protein complex. Although its functional role has not yet been completely elucidated, the finding that dysbindin assembles into the biogenesis of lysosome related organelles complex 1 (BLOC-1) suggests that it participates in intracellular trafficking and biogenesis of organelles and vesicles. Dysbindin is ubiquitous and in brain is expressed primarily in neurons. Variations at the dysbindin gene have been associated with increased risk for schizophrenia. As anomalies in retinal function have been reported in patients suffering from neuropsychiatric disorders, we investigated the expression of dysbindin in the retina. Our results show that differentially regulated dysbindin isoforms are expressed in rat retina during postnatal maturation. Interestingly, we found that dysbindin is mainly localized in Müller cells. The identification of dysbindin in glial cells may open new perspectives for a better understanding of the functional involvement of this protein in visual alterations associated to neuropsychiatric disorders.
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Affiliation(s)
- Andrea Matteucci
- Department of Cell Biology and Neuroscience, Istituto Superiore di Sanità, Viale Regina Elena 299, 00161 Roma, Italy.
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