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Dittman JS. Taking a closer look at the synapse. Proc Natl Acad Sci U S A 2024; 121:e2412457121. [PMID: 39102555 PMCID: PMC11331075 DOI: 10.1073/pnas.2412457121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/07/2024] Open
Affiliation(s)
- Jeremy S. Dittman
- Department of Biochemistry, Weill Cornell Medicine, New York, NY10065
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2
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Peng J, Liang D, Zhang Z. Palmitoylation of synaptic proteins: roles in functional regulation and pathogenesis of neurodegenerative diseases. Cell Mol Biol Lett 2024; 29:108. [PMID: 39127627 DOI: 10.1186/s11658-024-00625-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2024] [Accepted: 07/30/2024] [Indexed: 08/12/2024] Open
Abstract
Palmitoylation is a type of lipid modification that plays an important role in various aspects of neuronal function. Over the past few decades, several studies have shown that the palmitoylation of synaptic proteins is involved in neurotransmission and synaptic functions. Palmitoyl acyltransferases (PATs), which belong to the DHHC family, are major players in the regulation of palmitoylation. Dysregulated palmitoylation of synaptic proteins and mutated/dysregulated DHHC proteins are associated with several neurodegenerative diseases, such as Alzheimer's disease (AD), Huntington's disease (HD), and Parkinson's disease (PD). In this review, we summarize the recent discoveries on the subcellular distribution of DHHC proteins and analyze their expression patterns in different brain cells. In particular, this review discusses how palmitoylation of synaptic proteins regulates synaptic vesicle exocytotic fusion and the localization, clustering, and transport of several postsynaptic receptors, as well as the role of palmitoylation of other proteins in regulating synaptic proteins. Additionally, some of the specific known associations of these factors with neurodegenerative disorders are explored, with a few suggestions for the development of therapeutic strategies. Finally, this review provides possible directions for future research to reveal detailed and specific mechanisms underlying the roles of synaptic protein palmitoylation.
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Affiliation(s)
- Jiaying Peng
- Shenzhen Key Laboratory of Marine Bioresources and Ecology, Brain Disease and Big Data Research Institute, College of Life Sciences and Oceanography, Shenzhen University, Shenzhen, China
| | - Danchan Liang
- Shenzhen Key Laboratory of Marine Bioresources and Ecology, Brain Disease and Big Data Research Institute, College of Life Sciences and Oceanography, Shenzhen University, Shenzhen, China
| | - Zhonghao Zhang
- Shenzhen Key Laboratory of Marine Bioresources and Ecology, Brain Disease and Big Data Research Institute, College of Life Sciences and Oceanography, Shenzhen University, Shenzhen, China.
- Shenzhen-Hong Kong Institute of Brain Science-Shenzhen Fundamental Research Institutions, Shenzhen, China.
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3
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Liu W, Gao T, Li N, Shao S, Liu B. Vesicle fusion and release in neurons under dynamic mechanical equilibrium. iScience 2024; 27:109793. [PMID: 38736547 PMCID: PMC11088343 DOI: 10.1016/j.isci.2024.109793] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/14/2024] Open
Abstract
Vesicular fusion plays a pivotal role in cellular processes, involving stages like vesicle trafficking, fusion pore formation, content release, and membrane integration or separation. This dynamic process is regulated by a complex interplay of protein assemblies, osmotic forces, and membrane tension, which together maintain a mechanical equilibrium within the cell. Changes in cellular mechanics or external pressures prompt adjustments in this equilibrium, highlighting the system's adaptability. This review delves into the synergy between intracellular proteins, structural components, and external forces in facilitating vesicular fusion and release. It also explores how cells respond to mechanical stress, maintaining equilibrium and offering insights into vesicle fusion mechanisms and the development of neurological disorders.
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Affiliation(s)
- Wenhao Liu
- Cancer Hospital of Dalian University of Technology, Shenyang 110042, China
| | - Tianyu Gao
- Cancer Hospital of Dalian University of Technology, Shenyang 110042, China
| | - Na Li
- Cancer Hospital of Dalian University of Technology, Shenyang 110042, China
- Faculty of Medicine, Liaoning Key Lab of Integrated Circuit and Biomedical Electronic System, Dalian University of Technology, Dalian 116024, China
| | - Shuai Shao
- Cancer Hospital of Dalian University of Technology, Shenyang 110042, China
- Faculty of Medicine, Liaoning Key Lab of Integrated Circuit and Biomedical Electronic System, Dalian University of Technology, Dalian 116024, China
| | - Bo Liu
- Cancer Hospital of Dalian University of Technology, Shenyang 110042, China
- Faculty of Medicine, Liaoning Key Lab of Integrated Circuit and Biomedical Electronic System, Dalian University of Technology, Dalian 116024, China
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4
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Binotti B, Ninov M, Cepeda AP, Ganzella M, Matti U, Riedel D, Urlaub H, Sambandan S, Jahn R. ATG9 resides on a unique population of small vesicles in presynaptic nerve terminals. Autophagy 2024; 20:883-901. [PMID: 37881948 PMCID: PMC11062364 DOI: 10.1080/15548627.2023.2274204] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2023] [Accepted: 10/17/2023] [Indexed: 10/27/2023] Open
Abstract
In neurons, autophagosome biogenesis occurs mainly in distal axons, followed by maturation during retrograde transport. Autophagosomal growth depends on the supply of membrane lipids which requires small vesicles containing ATG9, a lipid scramblase essential for macroautophagy/autophagy. Here, we show that ATG9-containing vesicles are enriched in synapses and resemble synaptic vesicles in size and density. The proteome of ATG9-containing vesicles immuno-isolated from nerve terminals showed conspicuously low levels of trafficking proteins except of the AP2-complex and some enzymes involved in endosomal phosphatidylinositol metabolism. Super resolution microscopy of nerve terminals and isolated vesicles revealed that ATG9-containing vesicles represent a distinct vesicle population with limited overlap not only with synaptic vesicles but also other membranes of the secretory pathway, uncovering a surprising heterogeneity in their membrane composition. Our results are compatible with the view that ATG9-containing vesicles function as lipid shuttles that scavenge membrane lipids from various intracellular membranes to support autophagosome biogenesis.Abbreviations: AP: adaptor related protein complex: ATG2: autophagy related 2; ATG9: autophagy related 9; DNA PAINT: DNA-based point accumulation for imaging in nanoscale topography; DyMIN STED: dynamic minimum stimulated emission depletion; EL: endosome and lysosome; ER: endoplasmic reticulum; GA: Golgi apparatus; iBAQ: intensity based absolute quantification; LAMP: lysosomal-associated membrane protein; M6PR: mannose-6-phosphate receptor, cation dependent; Minflux: minimal photon fluxes; Mito: mitochondria; MS: mass spectrometry; PAS: phagophore assembly site; PM: plasma membrane; Px: peroxisome; RAB26: RAB26, member RAS oncogene family; RAB3A: RAB3A, member RAS oncogene family; RAB5A: RAB5A, member RAS oncogene family; SNARE: soluble N-ethylmaleimide-sensitive-factor attachment receptor; SVs: synaptic vesicles; SYP: synaptophysin; TGN: trans-Golgi network; TRAPP: transport protein particle; VTI1: vesicle transport through interaction with t-SNAREs.
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Affiliation(s)
- Beyenech Binotti
- Laboratory of Neurobiology, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
- Department of Biochemistry, Biocenter, University of Würzburg, Würzburg, Germany
| | - Momchil Ninov
- Laboratory of Neurobiology, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
- Bioanalytics, Institute of Clinical Chemistry, University Medical Center Göttingen, Germany
- Bioanalytical Mass Spectrometry, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
| | - Andreia P. Cepeda
- Bioanalytical Mass Spectrometry, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
| | - Marcelo Ganzella
- Laboratory of Neurobiology, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
| | - Ulf Matti
- Abberior Instruments GmbH, Göttingen, Germany
| | - Dietmar Riedel
- Facility for Transmission Electron Microscopy, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
| | - Henning Urlaub
- Bioanalytics, Institute of Clinical Chemistry, University Medical Center Göttingen, Germany
- Bioanalytical Mass Spectrometry, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
- Cluster of Excellence “Multiscale Bioimaging : from Molecular Machines to Networks of Excitable Cells” (MBExC), University of Göttingen, Göttingen, Germany
| | - Sivakumar Sambandan
- Laboratory of Neurobiology, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
- Synaptic Metal Ion Dynamics and Signalin, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
| | - Reinhard Jahn
- Laboratory of Neurobiology, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
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5
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Jahn R, Cafiso DC, Tamm LK. Mechanisms of SNARE proteins in membrane fusion. Nat Rev Mol Cell Biol 2024; 25:101-118. [PMID: 37848589 DOI: 10.1038/s41580-023-00668-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/06/2023] [Indexed: 10/19/2023]
Abstract
Soluble N-ethylmaleimide-sensitive factor attachment protein receptors (SNAREs) are a family of small conserved eukaryotic proteins that mediate membrane fusion between organelles and with the plasma membrane. SNAREs are directly or indirectly anchored to membranes. Prior to fusion, complementary SNAREs assemble between membranes with the aid of accessory proteins that provide a scaffold to initiate SNARE zippering, pulling the membranes together and mediating fusion. Recent advances have enabled the construction of detailed models describing bilayer transitions and energy barriers along the fusion pathway and have elucidated the structures of SNAREs complexed in various states with regulatory proteins. In this Review, we discuss how these advances are yielding an increasingly detailed picture of the SNARE-mediated fusion pathway, leading from first contact between the membranes via metastable non-bilayer intermediates towards the opening and expansion of a fusion pore. We describe how SNARE proteins assemble into complexes, how this assembly is regulated by accessory proteins and how SNARE complexes overcome the free energy barriers that prevent spontaneous membrane fusion.
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Affiliation(s)
- Reinhard Jahn
- Laboratory of Neurobiology, Max-Planck Institute for Multidisciplinary Sciences, Göttingen, Germany.
| | - David C Cafiso
- Department of Chemistry, University of Virginia, Charlottesville, VA, USA
| | - Lukas K Tamm
- Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, VA, USA
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6
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Martínez-Mármol R, Muhaisen A, Cotrufo T, Roselló-Busquets C, Ros O, Hernaiz-Llorens M, Pérez-Branguli F, Andrés RM, Parcerisas A, Pascual M, Ulloa F, Soriano E. Syntaxin-1 is necessary for UNC5A-C/Netrin-1-dependent macropinocytosis and chemorepulsion. Front Mol Neurosci 2023; 16:1253954. [PMID: 37829513 PMCID: PMC10565356 DOI: 10.3389/fnmol.2023.1253954] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2023] [Accepted: 09/04/2023] [Indexed: 10/14/2023] Open
Abstract
Introduction Brain connectivity requires correct axonal guidance to drive axons to their appropriate targets. This process is orchestrated by guidance cues that exert attraction or repulsion to developing axons. However, the intricacies of the cellular machinery responsible for the correct response of growth cones are just being unveiled. Netrin-1 is a bifunctional molecule involved in axon pathfinding and cell migration that induces repulsion during postnatal cerebellar development. This process is mediated by UNC5 homolog receptors located on external granule layer (EGL) tracts. Methods Biochemical, imaging and cell biology techniques, as well as syntaxin-1A/B (Stx1A/B) knock-out mice were used in primary cultures and brain explants. Results and discussion Here, we demonstrate that this response is characterized by enhanced membrane internalization through macropinocytosis, but not clathrin-mediated endocytosis. We show that UNC5A, UNC5B, and UNC5C receptors form a protein complex with the t-SNARE syntaxin-1. By combining botulinum neurotoxins, an shRNA knock-down strategy and Stx1 knock-out mice, we demonstrate that this SNARE protein is required for Netrin1-induced macropinocytosis and chemorepulsion, suggesting that Stx1 is crucial in regulating Netrin-1-mediated axonal guidance.
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Affiliation(s)
- Ramón Martínez-Mármol
- Department of Cell Biology, Physiology and Immunology, Faculty of Biology and Institute of Neurosciences, Universitat de Barcelona (UB), Barcelona, Spain
- Clem Jones Centre for Ageing Dementia Research, Queensland Brain Institute, The University of Queensland, Brisbane, QLD, Australia
| | - Ashraf Muhaisen
- Department of Cell Biology, Physiology and Immunology, Faculty of Biology and Institute of Neurosciences, Universitat de Barcelona (UB), Barcelona, Spain
- Centro de Investigación Biomédica en Red Sobre Enfermedades Neurodegenerativas (CIBERNED-CIBER), ISCIII, Madrid, Spain
| | - Tiziana Cotrufo
- Department of Cell Biology, Physiology and Immunology, Faculty of Biology and Institute of Neurosciences, Universitat de Barcelona (UB), Barcelona, Spain
- Centro de Investigación Biomédica en Red Sobre Enfermedades Neurodegenerativas (CIBERNED-CIBER), ISCIII, Madrid, Spain
| | - Cristina Roselló-Busquets
- Department of Cell Biology, Physiology and Immunology, Faculty of Biology and Institute of Neurosciences, Universitat de Barcelona (UB), Barcelona, Spain
| | - Oriol Ros
- Department of Cell Biology, Physiology and Immunology, Faculty of Biology and Institute of Neurosciences, Universitat de Barcelona (UB), Barcelona, Spain
| | - Marc Hernaiz-Llorens
- Department of Cell Biology, Physiology and Immunology, Faculty of Biology and Institute of Neurosciences, Universitat de Barcelona (UB), Barcelona, Spain
| | - Francesc Pérez-Branguli
- Department of Cell Biology, Physiology and Immunology, Faculty of Biology and Institute of Neurosciences, Universitat de Barcelona (UB), Barcelona, Spain
- IZKF Junior Research Group and BMBF Research Group Neuroscience, IZKF, Friedrich-Alexander-Universitaet Erlangen-Nuernberg, Erlangen, Germany
| | - Rosa Maria Andrés
- Department of Cell Biology, Physiology and Immunology, Faculty of Biology and Institute of Neurosciences, Universitat de Barcelona (UB), Barcelona, Spain
- Centro de Investigación Biomédica en Red Sobre Enfermedades Neurodegenerativas (CIBERNED-CIBER), ISCIII, Madrid, Spain
| | - Antoni Parcerisas
- Tissue Repair and Regeneration Laboratory (TR2Lab), Institut de Recerca i Innovació en Ciències de la Vida i de la Salut a la Catalunya Central (IRIS-CC), Vic, Spain
- Biosciences Department, Faculty of Sciences, Technology and Engineerings, University of Vic - Central University of Catalonia (UVic-UCC), Vic, Spain
| | - Marta Pascual
- Department of Cell Biology, Physiology and Immunology, Faculty of Biology and Institute of Neurosciences, Universitat de Barcelona (UB), Barcelona, Spain
- Centro de Investigación Biomédica en Red Sobre Enfermedades Neurodegenerativas (CIBERNED-CIBER), ISCIII, Madrid, Spain
| | - Fausto Ulloa
- Department of Cell Biology, Physiology and Immunology, Faculty of Biology and Institute of Neurosciences, Universitat de Barcelona (UB), Barcelona, Spain
- Centro de Investigación Biomédica en Red Sobre Enfermedades Neurodegenerativas (CIBERNED-CIBER), ISCIII, Madrid, Spain
| | - Eduardo Soriano
- Department of Cell Biology, Physiology and Immunology, Faculty of Biology and Institute of Neurosciences, Universitat de Barcelona (UB), Barcelona, Spain
- Centro de Investigación Biomédica en Red Sobre Enfermedades Neurodegenerativas (CIBERNED-CIBER), ISCIII, Madrid, Spain
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7
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Kim YK, Eom Y, Yoon H, Lee Y, Lee SH. Benzo[a]pyrene represses synaptic vesicle exocytosis by inhibiting P/Q-type calcium channels in hippocampal neurons. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2023; 263:115301. [PMID: 37506439 DOI: 10.1016/j.ecoenv.2023.115301] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/09/2023] [Revised: 07/17/2023] [Accepted: 07/21/2023] [Indexed: 07/30/2023]
Abstract
Humans are exposed to the common carcinogen benzo[a]pyrene (BaP) by ingesting contaminated foods and water or inhaling polluted air. Given the enriched lipids and reduced antioxidative properties in the brain and the accumulation of BaP in the brain due to its high lipophilicity, the brain is susceptible to BaP-induced toxicity. Exposure to BaP leads to impairments in learning and memory, increased anxiety behavior, and neuronal death. It induces protein dysfunctions in neuronal compartments that play essential roles in neuronal activity or physiology. However, the neurotoxicity of BaP on presynaptic terminals, which is crucial to neurotransmission by releasing synaptic vesicles that contain neurotransmitters, has not yet been investigated. In the present study, we investigated the toxicity of BaP at presynaptic terminals in living hippocampal neurons. These neurons were sourced from transgenic mice pups (postnatal 1-day, a total of 12 pups, equal numbers for each sex) that endogenously express synaptic vesicle-fused pHluorin, which is a green fluorescent protein that enables monitoring of synaptic vesicle dynamics. We observed that BaP suppressed synaptic vesicle exocytosis by inhibiting presynaptic Ca2+ entry via P/Q-type Ca2+ channels. Together with molecular docking simulation, we speculate that BaP and metabolites may bind to the P/Q Ca2+ channels. These results suggest the toxic mechanism of BaP exposure-induced abnormal behavior that provides a basis to evaluate the risk assessment of BaP-induced neurotoxicity.
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Affiliation(s)
- Yeong-Kyeong Kim
- College of Pharmacy, Chung-Ang University, Seoul 06974, Republic of Korea
| | - Yunkyung Eom
- College of Pharmacy, Chung-Ang University, Seoul 06974, Republic of Korea
| | - Hongryul Yoon
- College of Pharmacy, Chung-Ang University, Seoul 06974, Republic of Korea
| | - Yoonji Lee
- College of Pharmacy, Chung-Ang University, Seoul 06974, Republic of Korea.
| | - Sung Hoon Lee
- College of Pharmacy, Chung-Ang University, Seoul 06974, Republic of Korea.
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8
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Rothman JE, Grushin K, Bera M, Pincet F. Turbocharging synaptic transmission. FEBS Lett 2023; 597:2233-2249. [PMID: 37643878 DOI: 10.1002/1873-3468.14718] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2023] [Revised: 07/07/2023] [Accepted: 07/11/2023] [Indexed: 08/31/2023]
Abstract
Evidence from biochemistry, genetics, and electron microscopy strongly supports the idea that a ring of Synaptotagmin is central to the clamping and release of synaptic vesicles (SVs) for synchronous neurotransmission. Recent direct measurements in cell-free systems suggest there are 12 SNAREpins in each ready-release vesicle, consisting of six peripheral and six central SNAREpins. The six central SNAREpins are directly bound to the Synaptotagmin ring, are directly released by Ca++ , and they initially open the fusion pore. The six peripheral SNAREpins are indirectly bound to the ring, each linked to a central SNAREpin by a bridging molecule of Complexin. We suggest that the primary role of peripheral SNAREpins is to provide additional force to 'turbocharge' neurotransmitter release, explaining how it can occur much faster than other forms of membrane fusion. The SV protein Synaptophysin forms hexamers that bear two copies of the v-SNARE VAMP at each vertex, one likely assembling into a peripheral SNAREpin and the other into a central SNAREpin.
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Affiliation(s)
- James E Rothman
- Nanobiology Institute and Department of Cell Biology, Yale University, New Haven, CT, USA
| | - Kirill Grushin
- Nanobiology Institute and Department of Cell Biology, Yale University, New Haven, CT, USA
| | - Manindra Bera
- Nanobiology Institute and Department of Cell Biology, Yale University, New Haven, CT, USA
| | - Frederic Pincet
- Nanobiology Institute and Department of Cell Biology, Yale University, New Haven, CT, USA
- Laboratoire de Physique de l'Ecole Normale Supérieure, ENS, Université PSL, CNRS, Sorbonne Université, Université Paris Cité, Paris, France
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9
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Kalyana Sundaram RV, Chatterjee A, Bera M, Grushin K, Panda A, Li F, Coleman J, Lee S, Ramakrishnan S, Ernst AM, Gupta K, Rothman JE, Krishnakumar SS. Roles for diacylglycerol in synaptic vesicle priming and release revealed by complete reconstitution of core protein machinery. Proc Natl Acad Sci U S A 2023; 120:e2309516120. [PMID: 37590407 PMCID: PMC10450444 DOI: 10.1073/pnas.2309516120] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2023] [Accepted: 07/14/2023] [Indexed: 08/19/2023] Open
Abstract
Here, we introduce the full functional reconstitution of genetically validated core protein machinery (SNAREs, Munc13, Munc18, Synaptotagmin, and Complexin) for synaptic vesicle priming and release in a geometry that enables detailed characterization of the fate of docked vesicles both before and after release is triggered with Ca2+. Using this setup, we identify new roles for diacylglycerol (DAG) in regulating vesicle priming and Ca2+-triggered release involving the SNARE assembly chaperone Munc13. We find that low concentrations of DAG profoundly accelerate the rate of Ca2+-dependent release, and high concentrations reduce clamping and permit extensive spontaneous release. As expected, DAG also increases the number of docked, release-ready vesicles. Dynamic single-molecule imaging of Complexin binding to release-ready vesicles directly establishes that DAG accelerates the rate of SNAREpin assembly mediated by chaperones, Munc13 and Munc18. The selective effects of physiologically validated mutations confirmed that the Munc18-Syntaxin-VAMP2 "template" complex is a functional intermediate in the production of primed, release-ready vesicles, which requires the coordinated action of Munc13 and Munc18.
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Affiliation(s)
- R. Venkat Kalyana Sundaram
- Nanobiology Institute, Yale University School of Medicine, New Haven, CT06520
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT06520
| | - Atrouli Chatterjee
- Nanobiology Institute, Yale University School of Medicine, New Haven, CT06520
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT06520
| | - Manindra Bera
- Nanobiology Institute, Yale University School of Medicine, New Haven, CT06520
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT06520
| | - Kirill Grushin
- Nanobiology Institute, Yale University School of Medicine, New Haven, CT06520
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT06520
| | - Aniruddha Panda
- Nanobiology Institute, Yale University School of Medicine, New Haven, CT06520
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT06520
| | - Feng Li
- 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
| | - Seong Lee
- 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
| | - Andreas M. Ernst
- School of Biological Sciences, University of California San Diego, San Diego, CA92093
| | - Kallol Gupta
- Nanobiology Institute, Yale University School of Medicine, New Haven, CT06520
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT06520
| | - 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
| | - Shyam S. Krishnakumar
- Nanobiology Institute, Yale University School of Medicine, New Haven, CT06520
- Department of Neurology, Yale University School of Medicine, New Haven, CT06520
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10
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Bera M, Grushin K, Sundaram RVK, Shahanoor Z, Chatterjee A, Radhakrishnan A, Lee S, Padmanarayana M, Coleman J, Pincet F, Rothman JE, Dittman JS. Two successive oligomeric Munc13 assemblies scaffold vesicle docking and SNARE assembly to support neurotransmitter release. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.07.14.549017. [PMID: 37503179 PMCID: PMC10369971 DOI: 10.1101/2023.07.14.549017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/29/2023]
Abstract
The critical presynaptic protein Munc13 serves numerous roles in the process of docking and priming synaptic vesicles. Here we investigate the functional significance of two distinct oligomers of the Munc13 core domain (Munc13C) comprising C1-C2B-MUN-C2C. Oligomer interface point mutations that specifically destabilized either the trimer or lateral hexamer assemblies of Munc13C disrupted vesicle docking, trans-SNARE formation, and Ca 2+ -triggered vesicle fusion in vitro and impaired neurotransmitter secretion and motor nervous system function in vivo. We suggest that a progression of oligomeric Munc13 complexes couples vesicle docking and assembly of a precise number of SNARE molecules to support rapid and high-fidelity vesicle priming.
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11
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Sundaram RVK, Chatterjee A, Bera M, Grushin K, Panda A, Li F, Coleman J, Lee S, Ramakrishnan S, Ernst AM, Gupta K, Rothman JE, Krishnakumar SS. Novel Roles for Diacylglycerol in Synaptic Vesicle Priming and Release Revealed by Complete Reconstitution of Core Protein Machinery. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.06.05.543781. [PMID: 37333317 PMCID: PMC10274626 DOI: 10.1101/2023.06.05.543781] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/20/2023]
Abstract
Here we introduce the full functional reconstitution of genetically-validated core protein machinery (SNAREs, Munc13, Munc18, Synaptotagmin, Complexin) for synaptic vesicle priming and release in a geometry that enables detailed characterization of the fate of docked vesicles both before and after release is triggered with Ca 2+ . Using this novel setup, we discover new roles for diacylglycerol (DAG) in regulating vesicle priming and Ca 2+- triggered release involving the SNARE assembly chaperone Munc13. We find that low concentrations of DAG profoundly accelerate the rate of Ca 2+ -dependent release, and high concentrations reduce clamping and permit extensive spontaneous release. As expected, DAG also increases the number of ready-release vesicles. Dynamic single-molecule imaging of Complexin binding to ready-release vesicles directly establishes that DAG accelerates the rate of SNAREpin assembly mediated by Munc13 and Munc18 chaperones. The selective effects of physiologically validated mutations confirmed that the Munc18-Syntaxin-VAMP2 'template' complex is a functional intermediate in the production of primed, ready-release vesicles, which requires the coordinated action of Munc13 and Munc18. SIGNIFICANCE STATEMENT Munc13 and Munc18 are SNARE-associated chaperones that act as "priming" factors, facilitating the formation of a pool of docked, release-ready vesicles and regulating Ca 2+ -evoked neurotransmitter release. Although important insights into Munc18/Munc13 function have been gained, how they assemble and operate together remains enigmatic. To address this, we developed a novel biochemically-defined fusion assay which enabled us to investigate the cooperative action of Munc13 and Munc18 in molecular terms. We find that Munc18 nucleates the SNARE complex, while Munc13 promotes and accelerates the SNARE assembly in a DAG-dependent manner. The concerted action of Munc13 and Munc18 stages the SNARE assembly process to ensure efficient 'clamping' and formation of stably docked vesicles, which can be triggered to fuse rapidly (∼10 msec) upon Ca 2+ influx.
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Affiliation(s)
- R 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
| | - Atrouli Chatterjee
- 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
| | - 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
| | - Kirill Grushin
- 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
| | - Aniruddha Panda
- 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
| | - Feng Li
- 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
| | - Seong Lee
- 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
| | - Andreas M. Ernst
- School of Biological Sciences, University of California San Diego, La Jolla CA 92093, USA
| | - Kallol Gupta
- 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
| | - 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
| | - Shyam S. Krishnakumar
- Nanobiology Institute, Yale University School of Medicine, New Haven, CT 06520, USA
- Department of Neurology, Yale University School of Medicine, New Haven, CT 06520, USA
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12
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Brija EA, Guan Z, Jetti SK, Littleton JT. Stochastic RNA editing of the Complexin C-terminus within single neurons regulates neurotransmitter release. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.05.30.542887. [PMID: 37398117 PMCID: PMC10312600 DOI: 10.1101/2023.05.30.542887] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/04/2023]
Abstract
Neurotransmitter release requires assembly of the SNARE complex fusion machinery, with multiple SNARE-binding proteins regulating this process to control when and where synaptic vesicle fusion occurs. Complexin (Cpx) controls spontaneous and evoked neurotransmitter release by modulating SNARE complex zippering. Although the central SNARE-binding helix is essential, post-translational modifications to Cpx's C-terminal membrane-binding amphipathic helix modulate its activity. Here we demonstrate that RNA editing of the Cpx C-terminus regulates its ability to clamp SNARE-mediated fusion and alters presynaptic output. RNA editing of Cpx within single neurons is stochastic, generating up to eight edit variants that fine-tune neurotransmitter release by changing the subcellular localization and clamping properties of the protein. Similar editing rules for other synaptic genes were observed, indicating stochastic editing at single adenosines and across multiple mRNAs can generate unique synaptic proteomes within the same population of neurons to fine-tune presynaptic output.
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Affiliation(s)
- Elizabeth A Brija
- The Picower Institute for Learning and Memory, Department of Brain and Cognitive Sciences, Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139
| | - Zhuo Guan
- The Picower Institute for Learning and Memory, Department of Brain and Cognitive Sciences, Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139
| | - Suresh K Jetti
- The Picower Institute for Learning and Memory, Department of Brain and Cognitive Sciences, Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139
| | - J Troy Littleton
- The Picower Institute for Learning and Memory, Department of Brain and Cognitive Sciences, Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139
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13
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Chang HF, Schirra C, Pattu V, Krause E, Becherer U. Lytic granule exocytosis at immune synapses: lessons from neuronal synapses. Front Immunol 2023; 14:1177670. [PMID: 37275872 PMCID: PMC10233144 DOI: 10.3389/fimmu.2023.1177670] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2023] [Accepted: 05/09/2023] [Indexed: 06/07/2023] Open
Abstract
Regulated exocytosis is a central mechanism of cellular communication. It is not only the basis for neurotransmission and hormone release, but also plays an important role in the immune system for the release of cytokines and cytotoxic molecules. In cytotoxic T lymphocytes (CTLs), the formation of the immunological synapse is required for the delivery of the cytotoxic substances such as granzymes and perforin, which are stored in lytic granules and released via exocytosis. The molecular mechanisms of their fusion with the plasma membrane are only partially understood. In this review, we discuss the molecular players involved in the regulated exocytosis of CTL, highlighting the parallels and differences to neuronal synaptic transmission. Additionally, we examine the strengths and weaknesses of both systems to study exocytosis.
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14
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Hayashi T, Yano N, Kora K, Yokoyama A, Maizuru K, Kayaki T, Nishikawa K, Osawa M, Niwa A, Takenouchi T, Hijikata A, Shirai T, Suzuki H, Kosaki K, Saito MK, Takita J, Yoshida T. Involvement of mTOR pathway in neurodegeneration in NSF-related developmental and epileptic encephalopathy. Hum Mol Genet 2023; 32:1683-1697. [PMID: 36645181 PMCID: PMC10162430 DOI: 10.1093/hmg/ddad008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2022] [Revised: 01/08/2023] [Accepted: 01/11/2023] [Indexed: 01/17/2023] Open
Abstract
Membrane fusion is mediated by soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) proteins. During neurotransmitter exocytosis, SNARE proteins on a synaptic vesicle and the target membrane form a complex, resulting in neurotransmitter release. N-ethylmaleimide-sensitive factor (NSF), a homohexameric ATPase, disassembles the complex, allowing individual SNARE proteins to be recycled. Recently, the association between pathogenic NSF variants and developmental and epileptic encephalopathy (DEE) was reported; however, the molecular pathomechanism of NSF-related DEE remains unclear. Here, three patients with de novo heterozygous NSF variants were presented, of which two were associated with DEE and one with a very mild phenotype. One of the DEE patients also had hypocalcemia from parathyroid hormone deficiency and neuromuscular junction impairment. Using PC12 cells, a neurosecretion model, we show that NSF with DEE-associated variants impaired the recycling of vesicular membrane proteins and vesicle enlargement in response to exocytotic stimulation. In addition, DEE-associated variants caused neurodegenerative change and defective autophagy through overactivation of the mammalian/mechanistic target of rapamycin (mTOR) pathway. Treatment with rapamycin, an mTOR inhibitor or overexpression of wild-type NSF ameliorated these phenotypes. Furthermore, neurons differentiated from patient-derived induced pluripotent stem cells showed neurite degeneration, which was also alleviated by rapamycin treatment or gene correction using genome editing. Protein structure analysis of NSF revealed that DEE-associated variants might disrupt the transmission of the conformational change of NSF monomers and consequently halt the rotation of ATP hydrolysis, indicating a dominant negative mechanism. In conclusion, this study elucidates the pathomechanism underlying NSF-related DEE and identifies a potential therapeutic approach.
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Affiliation(s)
- Takahiro Hayashi
- Department of Pediatrics, Kyoto University Graduate School of Medicine, Kyoto 606-8507, Japan
| | - Naoko Yano
- Department of Pediatrics, Kyoto University Graduate School of Medicine, Kyoto 606-8507, Japan
| | - Kengo Kora
- Department of Pediatrics, Kyoto University Graduate School of Medicine, Kyoto 606-8507, Japan
| | - Atsushi Yokoyama
- Department of Pediatrics, Kyoto University Graduate School of Medicine, Kyoto 606-8507, Japan
| | - Kanako Maizuru
- Department of Pediatrics, Kyoto University Graduate School of Medicine, Kyoto 606-8507, Japan
| | - Taisei Kayaki
- Department of Pediatrics, Kyoto University Graduate School of Medicine, Kyoto 606-8507, Japan
| | - Kinuko Nishikawa
- Department of Pediatrics, Kyoto University Graduate School of Medicine, Kyoto 606-8507, Japan
| | - Mitsujiro Osawa
- Thyas Co. Ltd, Kyoto 606-8501, Japan
- Department of Clinical Application, Center for iPS Cell Research and Application (CiRA) Kyoto University, Kyoto 606-8507, Japan
| | - Akira Niwa
- Department of Clinical Application, Center for iPS Cell Research and Application (CiRA) Kyoto University, Kyoto 606-8507, Japan
| | - Toshiki Takenouchi
- Department of Pediatrics, Keio University School of Medicine, Shinjuku, Tokyo 160-8582, Japan
| | - Atsushi Hijikata
- Faculty of Bioscience, Nagahama Institute of Bio-Science and Technology, Nagahama, Shiga 526-0829, Japan
- School of Life Sciences, Tokyo University of Pharmacy and Life Sciences, Hachioji, Tokyo 192-0392, Japan
| | - Tsuyoshi Shirai
- Faculty of Bioscience, Nagahama Institute of Bio-Science and Technology, Nagahama, Shiga 526-0829, Japan
| | - Hisato Suzuki
- Center for Medical Genetics, Keio University School of Medicine, Shinjuku, Tokyo 160-8582, Japan
| | - Kenjiro Kosaki
- Center for Medical Genetics, Keio University School of Medicine, Shinjuku, Tokyo 160-8582, Japan
| | - Megumu K Saito
- Department of Clinical Application, Center for iPS Cell Research and Application (CiRA) Kyoto University, Kyoto 606-8507, Japan
| | - Junko Takita
- Department of Pediatrics, Kyoto University Graduate School of Medicine, Kyoto 606-8507, Japan
| | - Takeshi Yoshida
- Department of Pediatrics, Kyoto University Graduate School of Medicine, Kyoto 606-8507, Japan
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15
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Bykhovskaia M. Molecular Dynamics Simulations of the Proteins Regulating Synaptic Vesicle Fusion. MEMBRANES 2023; 13:307. [PMID: 36984694 PMCID: PMC10058449 DOI: 10.3390/membranes13030307] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/23/2023] [Revised: 02/11/2023] [Accepted: 03/01/2023] [Indexed: 06/18/2023]
Abstract
Neuronal transmitters are packaged in synaptic vesicles (SVs) and released by the fusion of SVs with the presynaptic membrane (PM). An inflow of Ca2+ into the nerve terminal triggers fusion, and the SV-associated protein Synaptotagmin 1 (Syt1) serves as a Ca2+ sensor. In preparation for fusion, SVs become attached to the PM by the SNARE protein complex, a coiled-coil bundle that exerts the force overcoming SV-PM repulsion. A cytosolic protein Complexin (Cpx) attaches to the SNARE complex and differentially regulates the evoked and spontaneous release components. It is still debated how the dynamic interactions of Syt1, SNARE proteins and Cpx lead to fusion. This problem is confounded by heterogeneity in the conformational states of the prefusion protein-lipid complex and by the lack of tools to experimentally monitor the rapid conformational transitions of the complex, which occur at a sub-millisecond scale. However, these complications can be overcome employing molecular dynamics (MDs), a computational approach that enables simulating interactions and conformational transitions of proteins and lipids. This review discusses the use of molecular dynamics for the investigation of the pre-fusion protein-lipid complex. We discuss the dynamics of the SNARE complex between lipid bilayers, as well as the interactions of Syt1 with lipids and SNARE proteins, and Cpx regulating the assembly of the SNARE complex.
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Affiliation(s)
- Maria Bykhovskaia
- Neurology Department, Wayne State University, Detroit, MI 48202, USA
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16
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Role of calcium-sensor proteins in cell membrane repair. Biosci Rep 2023; 43:232522. [PMID: 36728029 PMCID: PMC9970828 DOI: 10.1042/bsr20220765] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2022] [Revised: 01/20/2023] [Accepted: 02/01/2023] [Indexed: 02/03/2023] Open
Abstract
Cell membrane repair is a critical process used to maintain cell integrity and survival from potentially lethal chemical, and mechanical membrane injury. Rapid increases in local calcium levels due to a membrane rupture have been widely accepted as a trigger for multiple membrane-resealing models that utilize exocytosis, endocytosis, patching, and shedding mechanisms. Calcium-sensor proteins, such as synaptotagmins (Syt), dysferlin, S100 proteins, and annexins, have all been identified to regulate, or participate in, multiple modes of membrane repair. Dysfunction of membrane repair from inefficiencies or genetic alterations in these proteins contributes to diseases such as muscular dystrophy (MD) and heart disease. The present review covers the role of some of the key calcium-sensor proteins and their involvement in membrane repair.
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17
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Zhang L, Li L, Wei Z, Zhou H, Liu H, Wang S, Ren Y, Dai T, Wang J, Hu Z, Ma C. The C 2 and PH domains of CAPS constitute an effective PI(4,5)P2-binding unit essential for Ca 2+-regulated exocytosis. Structure 2023; 31:424-434.e6. [PMID: 36863339 DOI: 10.1016/j.str.2023.02.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2022] [Revised: 01/05/2023] [Accepted: 02/03/2023] [Indexed: 03/04/2023]
Abstract
Ca2+-dependent activator proteins for secretion (CAPSs) are required for Ca2+-regulated exocytosis in neurons and neuroendocrine cells. CAPSs contain a pleckstrin homology (PH) domain that binds PI(4,5)P2-membrane. There is also a C2 domain residing adjacent to the PH domain, but its function remains unclear. In this study, we solved the crystal structure of the CAPS-1 C2PH module. The structure showed that the C2 and PH tandem packs against one another mainly via hydrophobic residues. With this interaction, the C2PH module exhibited enhanced binding to PI(4,5)P2-membrane compared with the isolated PH domain. In addition, we identified a new PI(4,5)P2-binding site on the C2 domain. Disruption of either the tight interaction between the C2 and PH domains or the PI(4,5)P2-binding sites on both domains significantly impairs CAPS-1 function in Ca2+-regulated exocytosis at the Caenorhabditis elegans neuromuscular junction (NMJ). These results suggest that the C2 and PH domains constitute an effective unit to promote Ca2+-regulated exocytosis.
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Affiliation(s)
- Li Zhang
- Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, China
| | - Lei Li
- Clem Jones Centre for Ageing Dementia Research, Queensland Brain Institute, The University of Queensland, Brisbane, QLD, Australia
| | - Ziqing Wei
- Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, China; Department of Neurology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan, China
| | - Hao Zhou
- Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, China
| | - Haowen Liu
- Clem Jones Centre for Ageing Dementia Research, Queensland Brain Institute, The University of Queensland, Brisbane, QLD, Australia
| | - Shen Wang
- Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, China
| | - Yijing Ren
- Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, China
| | - Tiankai Dai
- Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, China
| | - Jiafan Wang
- Clem Jones Centre for Ageing Dementia Research, Queensland Brain Institute, The University of Queensland, Brisbane, QLD, Australia
| | - Zhitao Hu
- Clem Jones Centre for Ageing Dementia Research, Queensland Brain Institute, The University of Queensland, Brisbane, QLD, Australia.
| | - Cong Ma
- Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, China.
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18
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Li W, Xing Y, Wang Y, Xu T, Song E, Feng W. A non-canonical target-binding site in Munc18-1 domain 3b for assembling the Mint1-Munc18-1-syntaxin-1 complex. Structure 2023; 31:68-77.e5. [PMID: 36608665 DOI: 10.1016/j.str.2022.11.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2022] [Revised: 10/10/2022] [Accepted: 11/04/2022] [Indexed: 01/07/2023]
Abstract
As the prototype of Sec1/Munc18 (SM) family proteins, Munc18-1 can manipulate the distinct conformations of syntaxin-1 for controlling intracellular membrane fusion. The Munc18-1-interacting domain of Mint1 (Mint1-MID) binds to Munc18-1 together with syntaxin-1 to form a Mint1-Munc18-1-syntaxin-1 complex, but the mechanism underlying the complex assembly remains unclear. Here, we determine the structure of the Mint1-MID-Munc18-1-syntaxin-1 complex. Unexpectedly, Munc18-1 recognizes Mint1-MID and syntaxin-1 simultaneously via two opposite sites. The canonical central cavity between domains 1 and 3a of Munc18-1 embraces closed syntaxin-1, whereas the non-canonical basic pocket in domain 3b captures the acidic Mint1-MID helix. The domain 3b-mediated recognition of an acidic-helical motif is distinct from other target-recognition modes of Munc18-1. Mutations in the interface between domain 3b and Mint1-MID disrupt the assembly of the Mint1-Munc18-1-syntaxin-1 complex. This work reveals a non-canonical target-binding site in Munc18-1 domain 3b for assembling the Mint1-Munc18-1-syntaxin-1 complex.
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Affiliation(s)
- Wei Li
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, 15 Datun Road, Beijing 100101, China
| | - Ying Xing
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, 15 Datun Road, Beijing 100101, China; College of Life Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yue Wang
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, 15 Datun Road, Beijing 100101, China; College of Life Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Tao Xu
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, 15 Datun Road, Beijing 100101, China; College of Life Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Eli Song
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, 15 Datun Road, Beijing 100101, China.
| | - Wei Feng
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, 15 Datun Road, Beijing 100101, China; College of Life Sciences, University of Chinese Academy of Sciences, Beijing 100049, China.
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19
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Bykhovskaia M. Probabilities of evoked and spontaneous synaptic transmission at individual active zones: Lessons from Drosophila. Front Mol Neurosci 2023; 15:1110538. [PMID: 36683858 PMCID: PMC9846329 DOI: 10.3389/fnmol.2022.1110538] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2022] [Accepted: 12/12/2022] [Indexed: 01/05/2023] Open
Abstract
Nerve terminals release neuronal transmitters at morphological specializations known as active zones (AZs). Synaptic vesicle fusion at individual AZs is probabilistic, and this property is fundamental for the neuronal information transfer. Until recently, a lack of appropriate tools limited the studies of stochastic properties of neuronal secretion at individual AZs. However, Drosophila transgenic lines that express postsynaptically tethered Ca2+ sensor GCaMP enabled the visualization of single exocytic event at individual AZs. The present mini-review discusses how this powerful approach enables the investigation of the evoked and spontaneous transmission at single AZs and promotes the understanding of the properties of both release components.
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20
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Armanious A, Gerelli Y, Micciulla S, Pace HP, Welbourn RJL, Sjöberg M, Agnarsson B, Höök F. Probing the Separation Distance between Biological Nanoparticles and Cell Membrane Mimics Using Neutron Reflectometry with Sub-Nanometer Accuracy. J Am Chem Soc 2022; 144:20726-20738. [DOI: 10.1021/jacs.2c08456] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Antonius Armanious
- Department of Physics, Chalmers University of Technology, 41296Gothenburg, Sweden
| | - Yuri Gerelli
- Institut Max von Laue-Paul Langevin (ILL), 38042Grenoble, France
- Department of Life and Environmental Sciences, Università Politecnica delle Marche, 60131Ancona, Italy
| | | | - Hudson P. Pace
- Department of Physics, Chalmers University of Technology, 41296Gothenburg, Sweden
| | - Rebecca J. L. Welbourn
- ISIS Facility, STFC, Rutherford Appleton Laboratory, Chilton, Didcot, OxonOX11 0QX, United Kingdom
| | - Mattias Sjöberg
- Department of Physics, Chalmers University of Technology, 41296Gothenburg, Sweden
| | - Björn Agnarsson
- Department of Physics, Chalmers University of Technology, 41296Gothenburg, Sweden
| | - Fredrik Höök
- Department of Physics, Chalmers University of Technology, 41296Gothenburg, Sweden
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21
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Cheng X, Yan Z, Su Z, Liu J. The transforming growth factor beta ligand TIG-2 modulates the function of neuromuscular junction and muscle energy metabolism in Caenorhabditis elegans. Front Mol Neurosci 2022; 15:962974. [PMID: 36385772 PMCID: PMC9650414 DOI: 10.3389/fnmol.2022.962974] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2022] [Accepted: 10/03/2022] [Indexed: 07/22/2023] Open
Abstract
Deciphering the physiological function of TGF-β (the transforming growth factor beta) family ligands is import for understanding the role of TGF-β in animals' development and aging. Here, we investigate the function of TIG-2, one of the ligands in Caenorhabditis elegans TGF-β family, in animals' behavioral modulation. Our results show that a loss-of-function mutation in tig-2 gene result in slower locomotion speed in the early adulthood and an increased density of cholinergic synapses, but a decreased neurotransmitter release at neuromuscular junctions (NMJs). Further tissue-specific rescue results reveal that neuronal and intestinal TIG-2 are essential for the formation of cholinergic synapses at NMJs. Interestingly, tig-2(ok3416) mutant is characterized with reduced muscle mitochondria content and adenosine triphosphate (ATP) production, although the function of muscle acetylcholine receptors and the morphology muscle fibers in the mutant are comparable to that in wild-type animals. Our result suggests that TIG-2 from different neuron and intestine regulates worm locomotion by modulating synaptogenesis and neurotransmission at NMJs, as well as energy metabolism in postsynaptic muscle cells.
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Affiliation(s)
- Xinran Cheng
- Neuroscience Program, Department of Anatomy and Developmental Biology, Monash Biomedicine Discovery Institute, Monash University, Melbourne, VIC, Australia
| | - Zhenzhen Yan
- Neuroscience Program, Department of Anatomy and Developmental Biology, Monash Biomedicine Discovery Institute, Monash University, Melbourne, VIC, Australia
- Dr. Neher’s Biophysics Laboratory for Innovative Drug Discovery, State Key Laboratory of Quality Research in Chinese Medicine, Macau University of Science and Technology, Macao, Macao SAR, China
| | - Zexiong Su
- Neuroscience Program, Department of Anatomy and Developmental Biology, Monash Biomedicine Discovery Institute, Monash University, Melbourne, VIC, Australia
| | - Jie Liu
- Neuroscience Program, Department of Anatomy and Developmental Biology, Monash Biomedicine Discovery Institute, Monash University, Melbourne, VIC, Australia
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22
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Michetti C, Falace A, Benfenati F, Fassio A. Synaptic genes and neurodevelopmental disorders: From molecular mechanisms to developmental strategies of behavioral testing. Neurobiol Dis 2022; 173:105856. [PMID: 36070836 DOI: 10.1016/j.nbd.2022.105856] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2021] [Revised: 08/29/2022] [Accepted: 08/30/2022] [Indexed: 10/14/2022] Open
Abstract
Synaptopathies are a class of neurodevelopmental disorders caused by modification in genes coding for synaptic proteins. These proteins oversee the process of neurotransmission, mainly controlling the fusion and recycling of synaptic vesicles at the presynaptic terminal, the expression and localization of receptors at the postsynapse and the coupling between the pre- and the postsynaptic compartments. Murine models, with homozygous or heterozygous deletion for several synaptic genes or knock-in for specific pathogenic mutations, have been developed. They have proved to be extremely informative for understanding synaptic physiology, as well as for clarifying the patho-mechanisms leading to developmental delay, epilepsy and motor, cognitive and social impairments that are the most common clinical manifestations of neurodevelopmental disorders. However, the onset of these disorders emerges during infancy and adolescence while the behavioral phenotyping is often conducted in adult mice, missing important information about the impact of synaptic development and maturation on the manifestation of the behavioral phenotype. Here, we review the main achievements obtained by behavioral testing in murine models of synaptopathies and propose a battery of behavioral tests to improve classification, diagnosis and efficacy of potential therapeutic treatments. Our aim is to underlie the importance of studying behavioral development and better focusing on disease onset and phenotypes.
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Affiliation(s)
- Caterina Michetti
- Department of Experimental Medicine, University of Genoa, Genoa, Italy; Center for Synaptic Neuroscience, Istituto Italiano di Tecnologia, Genoa, Italy.
| | - Antonio Falace
- Pediatric Neurology, Neurogenetics and Neurobiology Unit and Laboratories, Children's Hospital A. Meyer-University of Florence, Florence, Italy
| | - Fabio Benfenati
- Center for Synaptic Neuroscience, Istituto Italiano di Tecnologia, Genoa, Italy; IRCCS Ospedale Policlinico San Martino, Genoa, Italy
| | - Anna Fassio
- Department of Experimental Medicine, University of Genoa, Genoa, Italy; IRCCS Ospedale Policlinico San Martino, Genoa, Italy.
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23
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Coffman RE, Kraichely KN, Kreutzberger AJB, Kiessling V, Tamm LK, Woodbury DJ. Drunken lipid membranes, not drunken SNARE proteins, promote fusion in a model of neurotransmitter release. Front Mol Neurosci 2022; 15:1022756. [PMID: 36311016 PMCID: PMC9614348 DOI: 10.3389/fnmol.2022.1022756] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2022] [Accepted: 09/20/2022] [Indexed: 11/29/2022] Open
Abstract
Alcohol affects many neuronal proteins that are upstream or down-stream of synaptic vesicle fusion and neurotransmitter release. Less well studied is alcohol’s effect on the fusion machinery including SNARE proteins and lipid membranes. Using a SNARE-driven fusion assay we show that fusion probability is significantly increased at 0.4% v/v (68 mM) ethanol; but not with methanol up to 10%. Ethanol appears to act directly on membrane lipids since experiments focused on protein properties [circular dichroism spectrometry, site-directed fluorescence interference contrast (sdFLIC) microscopy, and vesicle docking results] showed no significant changes up to 5% ethanol, but a protein-free fusion assay also showed increased lipid membrane fusion rates with 0.4% ethanol. These data show that the effects of high physiological doses of ethanol on SNARE-driven fusion are mediated through ethanol’s interaction with the lipid bilayer of membranes and not SNARE proteins, and that methanol affects lipid membranes and SNARE proteins only at high doses.
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Affiliation(s)
- Robert E. Coffman
- Neuroscience Center, Brigham Young University, Provo, UT, United States
| | - Katelyn N. Kraichely
- Department of Molecular Physiology and Biological Physics, University of Virginia Health System, Charlottesville, VA, United States
| | - Alex J. B. Kreutzberger
- Department of Molecular Physiology and Biological Physics, University of Virginia Health System, Charlottesville, VA, United States
| | - Volker Kiessling
- Department of Molecular Physiology and Biological Physics, University of Virginia Health System, Charlottesville, VA, United States
| | - Lukas K. Tamm
- Department of Molecular Physiology and Biological Physics, University of Virginia Health System, Charlottesville, VA, United States
| | - Dixon J. Woodbury
- Neuroscience Center, Brigham Young University, Provo, UT, United States
- Department of Cell Biology and Physiology, Brigham Young University, Provo, UT, United States
- *Correspondence: Dixon J. Woodbury,
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24
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Cui L, Li H, Xi Y, Hu Q, Liu H, Fan J, Xiang Y, Zhang X, Shui W, Lai Y. Vesicle trafficking and vesicle fusion: mechanisms, biological functions, and their implications for potential disease therapy. MOLECULAR BIOMEDICINE 2022; 3:29. [PMID: 36129576 PMCID: PMC9492833 DOI: 10.1186/s43556-022-00090-3] [Citation(s) in RCA: 24] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2022] [Accepted: 07/12/2022] [Indexed: 11/10/2022] Open
Abstract
Intracellular vesicle trafficking is the fundamental process to maintain the homeostasis of membrane-enclosed organelles in eukaryotic cells. These organelles transport cargo from the donor membrane to the target membrane through the cargo containing vesicles. Vesicle trafficking pathway includes vesicle formation from the donor membrane, vesicle transport, and vesicle fusion with the target membrane. Coat protein mediated vesicle formation is a delicate membrane budding process for cargo molecules selection and package into vesicle carriers. Vesicle transport is a dynamic and specific process for the cargo containing vesicles translocation from the donor membrane to the target membrane. This process requires a group of conserved proteins such as Rab GTPases, motor adaptors, and motor proteins to ensure vesicle transport along cytoskeletal track. Soluble N-ethyl-maleimide-sensitive factor (NSF) attachment protein receptors (SNARE)-mediated vesicle fusion is the final process for vesicle unloading the cargo molecules at the target membrane. To ensure vesicle fusion occurring at a defined position and time pattern in eukaryotic cell, multiple fusogenic proteins, such as synaptotagmin (Syt), complexin (Cpx), Munc13, Munc18 and other tethering factors, cooperate together to precisely regulate the process of vesicle fusion. Dysfunctions of the fusogenic proteins in SNARE-mediated vesicle fusion are closely related to many diseases. Recent studies have suggested that stimulated membrane fusion can be manipulated pharmacologically via disruption the interface between the SNARE complex and Ca2+ sensor protein. Here, we summarize recent insights into the molecular mechanisms of vesicle trafficking, and implications for the development of new therapeutics based on the manipulation of vesicle fusion.
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25
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Zhang Y, Ma L, Bao H. Energetics, kinetics, and pathways of SNARE assembly in membrane fusion. Crit Rev Biochem Mol Biol 2022; 57:443-460. [PMID: 36151854 PMCID: PMC9588726 DOI: 10.1080/10409238.2022.2121804] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Fusion of transmitter-containing vesicles with plasma membranes at the synaptic and neuromuscular junctions mediates neurotransmission and muscle contractions, respectively, thereby underlying all thoughts and actions. The fusion process is driven by the coupled folding and assembly of three synaptic SNARE proteins--syntaxin-1 and SNAP-25 on the target plasma membrane (t-SNAREs) and VAMP2 on the vesicular membrane (v-SNARE) into a four-helix bundle. Their assembly is chaperoned by Munc18-1 and many other proteins to achieve the speed and accuracy required for neurotransmission. However, the physiological pathway of SNARE assembly and its coupling to membrane fusion remains unclear. Here, we review recent progress in understanding SNARE assembly and membrane fusion, with a focus on results obtained by single-molecule manipulation approaches and electric recordings of single fusion pores. We describe two pathways of synaptic SNARE assembly, their associated intermediates, energetics, and kinetics. Assembly of the three SNAREs in vitro begins with the formation of a t-SNARE binary complex, on which VAMP2 folds in a stepwise zipper-like fashion. Munc18-1 significantly alters the SNARE assembly pathway: syntaxin-1 and VAMP2 first bind on the surface of Munc18-1 to form a template complex, with which SNAP-25 associates to conclude SNARE assembly and displace Munc18-1. During membrane fusion, multiple trans-SNARE complexes cooperate to open a dynamic fusion pore in a manner dependent upon their copy number and zippering states. Together, these results demonstrate that stepwise and cooperative SNARE assembly drive stagewise membrane fusion.
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Affiliation(s)
- Yongli Zhang
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT 06510, USA;,Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06511, USA;,Conatct: and
| | - Lu Ma
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT 06510, USA;,Present address: Beijing National Laboratory for Condensed Matter Physics and CAS Key Laboratory of Soft Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Huan Bao
- Department of Molecular Medicine, The Scripps Research Institute, 130 Scripps Way, Jupiter, Florida, 33458,Conatct: and
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26
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Synaptic Secretion and Beyond: Targeting Synapse and Neurotransmitters to Treat Neurodegenerative Diseases. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2022; 2022:9176923. [PMID: 35923862 PMCID: PMC9343216 DOI: 10.1155/2022/9176923] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/10/2022] [Revised: 05/16/2022] [Accepted: 06/04/2022] [Indexed: 11/17/2022]
Abstract
The nervous system is important, because it regulates the physiological function of the body. Neurons are the most basic structural and functional unit of the nervous system. The synapse is an asymmetric structure that is important for neuronal function. The chemical transmission mode of the synapse is realized through neurotransmitters and electrical processes. Based on vesicle transport, the abnormal information transmission process in the synapse can lead to a series of neurorelated diseases. Numerous proteins and complexes that regulate the process of vesicle transport, such as SNARE proteins, Munc18-1, and Synaptotagmin-1, have been identified. Their regulation of synaptic vesicle secretion is complicated and delicate, and their defects can lead to a series of neurodegenerative diseases. This review will discuss the structure and functions of vesicle-based synapses and their roles in neurons. Furthermore, we will analyze neurotransmitter and synaptic functions in neurodegenerative diseases and discuss the potential of using related drugs in their treatment.
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27
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Mochida S. Mechanisms of Synaptic Vesicle Exo- and Endocytosis. Biomedicines 2022; 10:1593. [PMID: 35884898 PMCID: PMC9313035 DOI: 10.3390/biomedicines10071593] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2022] [Revised: 06/21/2022] [Accepted: 06/22/2022] [Indexed: 01/05/2023] Open
Abstract
Within 1 millisecond of action potential arrival at presynaptic terminals voltage-gated Ca2+ channels open. The Ca2+ channels are linked to synaptic vesicles which are tethered by active zone proteins. Ca2+ entrance into the active zone triggers: (1) the fusion of the vesicle and exocytosis, (2) the replenishment of the active zone with vesicles for incoming exocytosis, and (3) various types of endocytosis for vesicle reuse, dependent on the pattern of firing. These time-dependent vesicle dynamics are controlled by presynaptic Ca2+ sensor proteins, regulating active zone scaffold proteins, fusion machinery proteins, motor proteins, endocytic proteins, several enzymes, and even Ca2+ channels, following the decay of Ca2+ concentration after the action potential. Here, I summarize the Ca2+-dependent protein controls of synchronous and asynchronous vesicle release, rapid replenishment of the active zone, endocytosis, and short-term plasticity within 100 msec after the action potential. Furthermore, I discuss the contribution of active zone proteins to presynaptic plasticity and to homeostatic readjustment during and after intense activity, in addition to activity-dependent endocytosis.
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Affiliation(s)
- Sumiko Mochida
- Department of Physiology, Tokyo Medical University, Tokyo 160-8402, Japan
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28
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Lazarevic V, Yang Y, Paslawski W, Svenningsson P. α-Synuclein induced cholesterol lowering increases tonic and reduces depolarization-evoked synaptic vesicle recycling and glutamate release. NPJ Parkinsons Dis 2022; 8:71. [PMID: 35672421 PMCID: PMC9174203 DOI: 10.1038/s41531-022-00334-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2021] [Accepted: 05/17/2022] [Indexed: 02/07/2023] Open
Abstract
α-Synuclein (α-syn) is a key molecule linked to Parkinson's disease pathology. Physiologically, the monomeric α-syn in the presynaptic termini is involved in regulation of neurotransmission, but the pathophysiology of extracellular monomeric α-syn is still unknown. Utilizing both in vivo and in vitro approaches, we investigated how extracellular α-syn impact presynaptic structure and function. Our data revealed that treatment with exogenous α-syn leads to increased tonic and decreased depolarization-evoked synaptic vesicle (SV) recycling and glutamate release. This was associated with mobilization of molecularly distinct SV pools and reorganization of active zone components. Our study also showed that exogenous α-syn impaired neuronal cholesterol level and that the cholesterol binding domain of α-syn was sufficient to exert the same presynaptic phenotype as the full-length protein. The present study sheds new light on physiological functions of extracellular α-syn in overall maintenance of presynaptic activity that involves the reorganization of both presynaptic compartment and cholesterol-rich plasma membrane domains.
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Affiliation(s)
- Vesna Lazarevic
- Department of Clinical Neuroscience, Karolinska Institute, Stockholm, Sweden
| | - Yunting Yang
- Department of Clinical Neuroscience, Karolinska Institute, Stockholm, Sweden
| | - Wojciech Paslawski
- Department of Clinical Neuroscience, Karolinska Institute, Stockholm, Sweden
| | - Per Svenningsson
- Department of Clinical Neuroscience, Karolinska Institute, Stockholm, Sweden.
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29
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Gething C, Ferrar J, Misra B, Howells G, Andrzejewski AL, Bowen ME, Choi UB. Conformational change of Syntaxin-3b in regulating SNARE complex assembly in the ribbon synapses. Sci Rep 2022; 12:9261. [PMID: 35661757 PMCID: PMC9166750 DOI: 10.1038/s41598-022-09654-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2021] [Accepted: 03/10/2022] [Indexed: 11/09/2022] Open
Abstract
Neurotransmitter release of synaptic vesicles relies on the assembly of the soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) complex, consisting of syntaxin and SNAP-25 on the plasma membrane and synaptobrevin on the synaptic vesicle. The formation of the SNARE complex progressively zippers towards the membranes, which drives membrane fusion between the plasma membrane and the synaptic vesicle. However, the underlying molecular mechanism of SNARE complex regulation is unclear. In this study, we investigated the syntaxin-3b isoform found in the retinal ribbon synapses using single-molecule fluorescence resonance energy transfer (smFRET) to monitor the conformational changes of syntaxin-3b that modulate the SNARE complex formation. We found that syntaxin-3b is predominantly in a self-inhibiting closed conformation, inefficiently forming the ternary SNARE complex. Conversely, a phosphomimetic mutation (T14E) at the N-terminal region of syntaxin-3b promoted the open conformation, similar to the constitutively open form of syntaxin LE mutant. When syntaxin-3b is bound to Munc18-1, SNARE complex formation is almost completely blocked. Surprisingly, the T14E mutation of syntaxin-3b partially abolishes Munc18-1 regulation, acting as a conformational switch to trigger SNARE complex assembly. Thus, we suggest a model where the conformational change of syntaxin-3b induced by phosphorylation initiates the release of neurotransmitters in the ribbon synapses.
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Affiliation(s)
- Claire Gething
- Department of Biochemistry, West Virginia University, Morgantown, WV, 26506, USA
| | - Joshua Ferrar
- Department of Biochemistry, West Virginia University, Morgantown, WV, 26506, USA
| | - Bishal Misra
- Department of Biochemistry, West Virginia University, Morgantown, WV, 26506, USA
| | - Giovanni Howells
- Department of Biochemistry, West Virginia University, Morgantown, WV, 26506, USA
| | | | - Mark E Bowen
- Department of Physiology and Biophysics, Stony Brook University, Stony Brook, NY, 11794, USA.,Quantum-Si, Inc, Guilford, CT, 06437, USA
| | - Ucheor B Choi
- Department of Biochemistry, West Virginia University, Morgantown, WV, 26506, USA. .,Quantum-Si, Inc, Guilford, CT, 06437, USA.
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30
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Bera M, Ramakrishnan S, Coleman J, Krishnakumar SS, Rothman JE. Molecular determinants of complexin clamping and activation function. eLife 2022; 11:e71938. [PMID: 35442188 PMCID: PMC9020821 DOI: 10.7554/elife.71938] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2021] [Accepted: 03/15/2022] [Indexed: 11/13/2022] Open
Abstract
Previously we reported that Synaptotagmin-1 and Complexin synergistically clamp the SNARE assembly process to generate and maintain a pool of docked vesicles that fuse rapidly and synchronously upon Ca2+ influx (Ramakrishnan et al., 2020). Here, using the same in vitro single-vesicle fusion assay, we determine the molecular details of the Complexin-mediated fusion clamp and its role in Ca2+-activation. We find that a delay in fusion kinetics, likely imparted by Synaptotagmin-1, is needed for Complexin to block fusion. Systematic truncation/mutational analyses reveal that continuous alpha-helical accessory-central domains of Complexin are essential for its inhibitory function and specific interaction of the accessory helix with the SNAREpins enhances this functionality. The C-terminal domain promotes clamping by locally elevating Complexin concentration through interactions with the membrane. Independent of their clamping functions, the accessory-central helical domains of Complexin also contribute to rapid Ca2+-synchronized vesicle release by increasing the probability of fusion from the clamped state.
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Affiliation(s)
- Manindra Bera
- Yale Nanobiology InstituteNew HavenUnited States
- Department of Cell Biology, Yale University School of MedicineNew HavenUnited States
| | - Sathish Ramakrishnan
- Yale Nanobiology InstituteNew HavenUnited States
- Department of Pathology, Yale University School of MedicineNew HavenUnited States
| | - Jeff Coleman
- Yale Nanobiology InstituteNew HavenUnited States
- Department of Cell Biology, Yale University School of MedicineNew HavenUnited States
| | - Shyam S Krishnakumar
- Yale Nanobiology InstituteNew HavenUnited States
- Departments of Neurology, Yale University School of MedicineNew HavenUnited States
| | - James E Rothman
- Yale Nanobiology InstituteNew HavenUnited States
- Department of Cell Biology, Yale University School of MedicineNew HavenUnited States
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31
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Shahoha M, Cohen R, Ben-Simon Y, Ashery U. cAMP-Dependent Synaptic Plasticity at the Hippocampal Mossy Fiber Terminal. Front Synaptic Neurosci 2022; 14:861215. [PMID: 35444523 PMCID: PMC9013808 DOI: 10.3389/fnsyn.2022.861215] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2022] [Accepted: 02/23/2022] [Indexed: 11/24/2022] Open
Abstract
Cyclic adenosine monophosphate (cAMP) is a crucial second messenger involved in both pre- and postsynaptic plasticity in many neuronal types across species. In the hippocampal mossy fiber (MF) synapse, cAMP mediates presynaptic long-term potentiation and depression. The main cAMP-dependent signaling pathway linked to MF synaptic plasticity acts via the activation of the protein kinase A (PKA) molecular cascade. Accordingly, various downstream putative synaptic PKA target proteins have been linked to cAMP-dependent MF synaptic plasticity, such as synapsin, rabphilin, synaptotagmin-12, RIM1a, tomosyn, and P/Q-type calcium channels. Regulating the expression of some of these proteins alters synaptic release probability and calcium channel clustering, resulting in short- and long-term changes to synaptic efficacy. However, despite decades of research, the exact molecular mechanisms by which cAMP and PKA exert their influences in MF terminals remain largely unknown. Here, we review current knowledge of different cAMP catalysts and potential downstream PKA-dependent molecular cascades, in addition to non-canonical cAMP-dependent but PKA-independent cascades, which might serve as alternative, compensatory or competing pathways to the canonical PKA cascade. Since several other central synapses share a similar form of presynaptic plasticity with the MF, a better description of the molecular mechanisms governing MF plasticity could be key to understanding the relationship between the transcriptional and computational levels across brain regions.
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Affiliation(s)
- Meishar Shahoha
- Faculty of Life Sciences, School of Neurobiology, Biochemistry and Biophysics, Tel Aviv University, Tel Aviv, Israel
- Sagol School of Neuroscience, Tel Aviv University, Tel Aviv, Israel
| | - Ronni Cohen
- Faculty of Life Sciences, School of Neurobiology, Biochemistry and Biophysics, Tel Aviv University, Tel Aviv, Israel
- Sagol School of Neuroscience, Tel Aviv University, Tel Aviv, Israel
| | - Yoav Ben-Simon
- Department of Neurophysiology, Vienna Medical University, Vienna, Austria
- *Correspondence: Yoav Ben-Simon,
| | - Uri Ashery
- Faculty of Life Sciences, School of Neurobiology, Biochemistry and Biophysics, Tel Aviv University, Tel Aviv, Israel
- Sagol School of Neuroscience, Tel Aviv University, Tel Aviv, Israel
- Uri Ashery,
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32
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Wang S, Ma C. Neuronal SNARE complex assembly guided by Munc18-1 and Munc13-1. FEBS Open Bio 2022; 12:1939-1957. [PMID: 35278279 PMCID: PMC9623535 DOI: 10.1002/2211-5463.13394] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2022] [Revised: 02/28/2022] [Accepted: 03/10/2022] [Indexed: 01/25/2023] Open
Abstract
Neurotransmitter release by Ca2+ -triggered synaptic vesicle exocytosis is essential for information transmission in the nervous system. The soluble N-ethylmaleimide sensitive factor attachment protein receptors (SNAREs) syntaxin-1, SNAP-25, and synaptobrevin-2 form the SNARE complex to bring synaptic vesicles and the plasma membranes together and to catalyze membrane fusion. Munc18-1 and Munc13-1 regulate synaptic vesicle priming via orchestrating neuronal SNARE complex assembly. In this review, we summarize recent advances toward the functions and molecular mechanisms of Munc18-1 and Munc13-1 in guiding neuronal SNARE complex assembly, and discuss the functional similarities and differences between Munc18-1 and Munc13-1 in neurons and their homologs in other intracellular membrane trafficking systems.
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Affiliation(s)
- Shen Wang
- Key Laboratory of Molecular Biophysics of the Ministry of EducationCollege of Life Science and TechnologyHuazhong University of Science and TechnologyWuhanChina
| | - Cong Ma
- Key Laboratory of Molecular Biophysics of the Ministry of EducationCollege of Life Science and TechnologyHuazhong University of Science and TechnologyWuhanChina
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33
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Abstract
Fundamental discoveries have shaped our molecular understanding of presynaptic processes, such as neurotransmitter release, active zone organization and mechanisms of synaptic vesicle (SV) recycling. However, certain regulatory steps still remain incompletely understood. Protein liquid-liquid phase separation (LLPS) and its role in SV clustering and active zone regulation now introduce a new perception of how the presynapse and its different compartments are organized. This article highlights the newly emerging concept of LLPS at the synapse, providing a systematic overview on LLPS tendencies of over 500 presynaptic proteins, spotlighting individual proteins and discussing recent progress in the field. Newly discovered LLPS systems like ELKS/liprin-alpha and Eps15/FCho are put into context, and further LLPS candidate proteins, including epsin1, dynamin, synaptojanin, complexin and rabphilin-3A, are highlighted.
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Affiliation(s)
- Janin Lautenschläger
- Department of Clinical Neurosciences, Cambridge Institute for Medical Research, University of Cambridge, Cambridge CB2 0XY, UK
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34
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Xia X, Wang Y, Qin Y, Zhao S, Zheng JC. Exosome: A novel neurotransmission modulator or non-canonical neurotransmitter? Ageing Res Rev 2022; 74:101558. [PMID: 34990846 DOI: 10.1016/j.arr.2021.101558] [Citation(s) in RCA: 27] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2021] [Revised: 08/13/2021] [Accepted: 12/30/2021] [Indexed: 02/08/2023]
Abstract
Neurotransmission is the electrical impulse-triggered propagation of signals between neurons or between neurons and other cell types such as skeletal muscle cells. Recent studies point out the involvement of exosomes, a type of small bilipid layer-enclosed extracellular vesicles, in regulating neurotransmission. Through horizontally transferring proteins, lipids, and nucleic acids, exosomes can modulate synaptic activities rapidly by controlling neurotransmitter release or progressively by regulating neural plasticity including synapse formation, neurite growth & removal, and axon guidance & elongation. In this review, we summarize the similarities and differences between exosomes and synaptic vesicles in their biogenesis, contents, and release. We also highlight the recent progress made in demonstrating the biological roles of exosome in regulating neurotransmission, and propose a modified model of neurotransmission, in which exosomes act as novel neurotransmitters. Lastly, we provide a comprehensive discussion of the enlightenment of the current knowledge on neurotransmission to the future directions of exosome research.
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35
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Ma L, Ge J, Bian X, Zhang Y. Single-Molecule Optical Tweezers Study of Protein-Membrane Interactions. Methods Mol Biol 2022; 2473:367-383. [PMID: 35819776 DOI: 10.1007/978-1-0716-2209-4_23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Numerous proteins directly or indirectly bind membranes to exert their roles in a wide variety of biological processes. Such membrane binding often occurs in the presence of an external mechanical force. It remains challenging to quantify these interactions using traditional experimental approaches based on a large number of molecules, due to ensemble averaging or the lack of mechanical force. Here we described a new single-molecule approach based on high-resolution optical tweezers to characterize protein-membrane interactions. A single membrane binding protein is attached to the lipid bilayer coated on a silica bead via a flexible polypeptide linker, tethered to another bead via a long DNA handle, and pulled away from the bilayer using optical tweezers. Dynamic protein binding and unbinding is detected by the corresponding changes in the extension of the protein-DNA tether with high spatiotemporal resolution, which reveals the membrane binding affinity, kinetics, and intermediates. We demonstrated the method using C2 domains of extended synaptotagmin 2 (E-Syt2) with a detailed protocol. The method can be widely applied to investigate complex protein-membrane interactions under well-controlled experimental conditions.
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Affiliation(s)
- Lu Ma
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT, USA
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, China
| | - Jinghua Ge
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT, USA
| | - Xin Bian
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT, USA
- State Key Laboratory of Medicinal Chemical Biology, College of Life Sciences, Nankai University, Tianjin, China
| | - Yongli Zhang
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT, USA.
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36
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Jin H, Ge J, Yang J, Zhang Y. Single-Molecule Manipulation Study of Chaperoned SNARE Folding and Assembly with Optical Tweezers. Methods Mol Biol 2022; 2478:461-481. [PMID: 36063331 DOI: 10.1007/978-1-0716-2229-2_17] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Intracellular membrane fusion is primarily driven by coupled folding and assembly of soluble N-ethylmaleimide-sensitive factor attachment protein receptors (SNAREs). SNARE assembly is intrinsically inefficient and must be chaperoned by a family of evolutionarily and structurally conserved Sec1/Munc-18 (SM) proteins. The physiological pathway of the chaperoned SNARE assembly has not been well understood, partly due to the difficulty in dissecting the many intermediates and pathways of SNARE assembly and measure their associated energetics and kinetics. Optical tweezers have proven to be a powerful tool to characterize the intermediates involved in the chaperoned SNARE assembly. Here, we demonstrate the application of optical tweezers combined with a homemade microfluidic system into studies of synaptic SNARE assembly chaperoned by their cognate SM protein Munc18-1. Three synaptic SNAREs and Munc18-1 constitute the core machinery for synaptic vesicle fusion involved in neurotransmitter release. Many other proteins further regulate the core machinery to enable fusion at the right time and location. The methods described here can be applied to other proteins that regulate SNARE assembly to control membrane fusion involved in numerous biological and physiological processes.
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Affiliation(s)
- Huaizhou Jin
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT, USA
- College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, China
| | - Jinghua Ge
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT, USA
| | - Jie Yang
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT, USA
| | - Yongli Zhang
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT, USA.
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, USA.
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37
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Mertins J, Finke J, Sies R, Rink KM, Hasenauer J, Lang T. The mesoscale organization of syntaxin 1A and SNAP25 is determined by SNARE-SNARE interactions. eLife 2021; 10:69236. [PMID: 34779769 PMCID: PMC8629428 DOI: 10.7554/elife.69236] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2021] [Accepted: 11/14/2021] [Indexed: 01/01/2023] Open
Abstract
SNARE proteins have been described as the effectors of fusion events in the secretory pathway more than two decades ago. The strong interactions between SNARE domains are clearly important in membrane fusion, but it is unclear whether they are involved in any other cellular processes. Here, we analyzed two classical SNARE proteins, syntaxin 1A and SNAP25. Although they are supposed to be engaged in tight complexes, we surprisingly find them largely segregated in the plasma membrane. Syntaxin 1A only occupies a small fraction of the plasma membrane area. Yet, we find it is able to redistribute the far more abundant SNAP25 on the mesoscale by gathering crowds of SNAP25 molecules onto syntaxin clusters in a SNARE-domain-dependent manner. Our data suggest that SNARE domain interactions are not only involved in driving membrane fusion on the nanoscale, but also play an important role in controlling the general organization of proteins on the mesoscale. Further, we propose these mechanisms preserve active syntaxin 1A–SNAP25 complexes at the plasma membrane.
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Affiliation(s)
- Jasmin Mertins
- Departments of Membrane Biochemistry, Life & Medical Sciences (LIMES) Institute, University of Bonn, Bonn, Germany
| | - Jérôme Finke
- Departments of Membrane Biochemistry, Life & Medical Sciences (LIMES) Institute, University of Bonn, Bonn, Germany
| | - Ricarda Sies
- Departments of Membrane Biochemistry, Life & Medical Sciences (LIMES) Institute, University of Bonn, Bonn, Germany
| | - Kerstin M Rink
- Heidelberg University Biochemistry Center (BZH), Heidelberg, Germany
| | - Jan Hasenauer
- Computational Life Sciences, Life & Medical Sciences (LIMES) Institute, University of Bonn, Bonn, Germany.,Interdisciplinary Research Unit Mathematics and Life Sciences, University of Bonn, Bonn, Germany.,Institute of Computational Biology, Helmholtz Center Munich - German Research Center for Environmental Health, Neuherberg, Germany
| | - Thorsten Lang
- Departments of Membrane Biochemistry, Life & Medical Sciences (LIMES) Institute, University of Bonn, Bonn, Germany
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38
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Peters JJ, Leitz J, Oses-Prieto JA, Burlingame AL, Brunger AT. Molecular Characterization of AMPA-Receptor-Containing Vesicles. Front Mol Neurosci 2021; 14:754631. [PMID: 34720876 PMCID: PMC8554035 DOI: 10.3389/fnmol.2021.754631] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2021] [Accepted: 09/16/2021] [Indexed: 12/13/2022] Open
Abstract
Regulated delivery of AMPA receptors (AMPARs) to the postsynaptic membrane is an essential step in synaptic strength modification, and in particular, long-term potentiation (LTP). While LTP has been extensively studied using electrophysiology and light microscopy, several questions regarding the molecular mechanisms of AMPAR delivery via trafficking vesicles remain outstanding, including the gross molecular make up of AMPAR trafficking organelles and identification and location of calcium sensors required for SNARE complex-dependent membrane fusion of such trafficking vesicles with the plasma membrane. Here, we isolated AMPA-containing vesicles (ACVs) from whole mouse brains via immunoisolation and characterized them using immunoelectron microscopy, immunoblotting, and liquid chromatography–tandem mass spectrometry (LC–MS/MS). We identified several proteins on ACVs that were previously found to play a role in AMPAR trafficking, including synaptobrevin-2, Rabs, the SM protein Munc18-1, the calcium-sensor synaptotagmin-1, as well as several new candidates, including synaptophysin and synaptogyrin on ACV membranes. Additionally, we identified two populations of ACVs based on size and molecular composition: small-diameter, synaptobrevin-2- and GluA1-containing ACVs, and larger transferrin- receptor-, GluA1-, GluA2-, and GluA3-containing ACVs. The small-diameter population of ACVs may represent a fusion-capable population of vesicles due to the presence of synaptobrevin-2. Because the fusion of ACVs may be a requisite of LTP, this population could represent trafficking vesicles related to LTP.
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Affiliation(s)
- John Jacob Peters
- Department of Molecular and Cellular Physiology, Stanford University, Stanford, CA, United States.,Department of Neurology and Neurological Sciences, Stanford University, Stanford, CA, United States.,Department of Structural Biology, Stanford University, Stanford, CA, United States.,Department of Photon Science, Stanford University, Stanford, CA, United States.,Howard Hughes Medical Institute, Stanford University, Stanford, CA, United States
| | - Jeremy Leitz
- Department of Molecular and Cellular Physiology, Stanford University, Stanford, CA, United States.,Department of Neurology and Neurological Sciences, Stanford University, Stanford, CA, United States.,Department of Structural Biology, Stanford University, Stanford, CA, United States.,Department of Photon Science, Stanford University, Stanford, CA, United States.,Howard Hughes Medical Institute, Stanford University, Stanford, CA, United States
| | - Juan A Oses-Prieto
- Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, CA, United States
| | - Alma L Burlingame
- Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, CA, United States
| | - Axel T Brunger
- Department of Molecular and Cellular Physiology, Stanford University, Stanford, CA, United States.,Department of Neurology and Neurological Sciences, Stanford University, Stanford, CA, United States.,Department of Structural Biology, Stanford University, Stanford, CA, United States.,Department of Photon Science, Stanford University, Stanford, CA, United States.,Howard Hughes Medical Institute, Stanford University, Stanford, CA, United States
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39
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Satake SI, Konishi S. Topographical distance between presynaptic Ca 2+ channels and exocytotic Ca 2+ sensors contributes to differential facilitatory actions of roscovitine on neurotransmitter release at cerebellar glutamatergic and GABAergic synapses. Eur J Neurosci 2021; 54:7048-7062. [PMID: 34622493 DOI: 10.1111/ejn.15487] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2021] [Revised: 09/27/2021] [Accepted: 09/29/2021] [Indexed: 11/29/2022]
Abstract
Calcium influx into presynaptic terminals through voltage-gated Ca2+ channels triggers univesicular or multivesicular release of neurotransmitters depending on the characteristics of the release machinery. However, the mechanisms underlying multivesicular release (MVR) and its regulation remain unclear. Previous studies showed that in rat cerebellum, the cyclin-dependent kinase inhibitor roscovitine profoundly increases excitatory postsynaptic current (EPSC) amplitudes at granule cell (GC)-Purkinje cell (PC) synapses by enhancing the MVR of glutamate. This compound can also moderately augment the amplitude and prolong the decay time of inhibitory postsynaptic currents (IPSCs) at molecular layer interneuron (MLI)-PC synapses via MVR enhancement and GABA spillover, thus allowing for persistent activation of perisynaptic GABA receptors. The enhanced MVR may depend on the driving force for Cav 2.1 channel-mediated Ca2+ influx. To determine whether the distinct spatiotemporal dynamics of presynaptic Ca2+ influence MVR, we compared the effects of slow and fast Ca2+ chelators, that is, EGTA and BAPTA, respectively, on roscovitine-induced actions at GC-PC and MLI-PC synapses. Membrane-permeable EGTA-AM decreased GC-PC EPSC and MLI-PC IPSC amplitudes to a similar extent but suppressed the roscovitine-induced enhancement of EPSCs. In contrast, BAPTA-AM attenuated the effects of roscovitine on IPSCs. These results suggest that roscovitine augmented glutamate release by activating the release machinery located distally from the Cav 2.1 channel clusters, while it enhanced GABA release in a manner less dependent on those at distal sites. Therefore, the spatial relationships among Ca2+ channels, buffers, and sensors are critical determinants of the differential facilitatory actions of roscovitine on glutamatergic and GABAergic synapses in the cerebellar cortex.
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Affiliation(s)
- Shin' Ichiro Satake
- Brain Research Support Center, National Institute for Physiological Sciences (NIPS), Okazaki, Japan.,School of Life Science, The Graduate University for Advanced Studies (SOKENDAI), Okazaki, Japan
| | - Shiro Konishi
- Department of Neurophysiology, Kagawa School of Pharmaceutical Sciences, Tokushima Bunri University, Sanuki, Japan
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40
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Bakr M, Jullié D, Krapivkina J, Paget-Blanc V, Bouit L, Petersen JD, Retailleau N, Breillat C, Herzog E, Choquet D, Perrais D. The vSNAREs VAMP2 and VAMP4 control recycling and intracellular sorting of post-synaptic receptors in neuronal dendrites. Cell Rep 2021; 36:109678. [PMID: 34496238 DOI: 10.1016/j.celrep.2021.109678] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2020] [Revised: 06/25/2021] [Accepted: 08/17/2021] [Indexed: 11/28/2022] Open
Abstract
The endosomal recycling system dynamically tunes synaptic strength, which underlies synaptic plasticity. Exocytosis is involved in the expression of long-term potentiation (LTP), as postsynaptic cleavage of the SNARE (soluble NSF-attachment protein receptor) protein VAMP2 by tetanus toxin blocks LTP. Moreover, induction of LTP increases the exocytosis of transferrin receptors (TfRs) and markers of recycling endosomes (REs), as well as post-synaptic AMPA type receptors (AMPARs). However, the interplay between AMPAR and TfR exocytosis remains unclear. Here, we identify VAMP4 as the vesicular SNARE that mediates most dendritic RE exocytosis. In contrast, VAMP2 plays a minor role in RE exocytosis. LTP induction increases the exocytosis of both VAMP2- and VAMP4-labeled organelles. Knock down (KD) of VAMP4 decreases TfR recycling but increases AMPAR recycling. Moreover, VAMP4 KD increases AMPAR-mediated synaptic transmission, which consequently occludes LTP expression. The opposing changes in AMPAR and TfR recycling upon VAMP4 KD reveal their sorting into separate endosomal populations.
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Affiliation(s)
- May Bakr
- Univ. Bordeaux, CNRS, Interdisciplinary Institute for Neuroscience, IINS, UMR 5297, 33000 Bordeaux, France
| | - Damien Jullié
- Univ. Bordeaux, CNRS, Interdisciplinary Institute for Neuroscience, IINS, UMR 5297, 33000 Bordeaux, France
| | - Julia Krapivkina
- Univ. Bordeaux, CNRS, Interdisciplinary Institute for Neuroscience, IINS, UMR 5297, 33000 Bordeaux, France
| | - Vincent Paget-Blanc
- Univ. Bordeaux, CNRS, Interdisciplinary Institute for Neuroscience, IINS, UMR 5297, 33000 Bordeaux, France
| | - Lou Bouit
- Univ. Bordeaux, CNRS, Interdisciplinary Institute for Neuroscience, IINS, UMR 5297, 33000 Bordeaux, France
| | - Jennifer D Petersen
- Univ. Bordeaux, CNRS, Interdisciplinary Institute for Neuroscience, IINS, UMR 5297, 33000 Bordeaux, France
| | - Natacha Retailleau
- Univ. Bordeaux, CNRS, Interdisciplinary Institute for Neuroscience, IINS, UMR 5297, 33000 Bordeaux, France
| | - Christelle Breillat
- Univ. Bordeaux, CNRS, Interdisciplinary Institute for Neuroscience, IINS, UMR 5297, 33000 Bordeaux, France
| | - Etienne Herzog
- Univ. Bordeaux, CNRS, Interdisciplinary Institute for Neuroscience, IINS, UMR 5297, 33000 Bordeaux, France
| | - Daniel Choquet
- Univ. Bordeaux, CNRS, Interdisciplinary Institute for Neuroscience, IINS, UMR 5297, 33000 Bordeaux, France; Univ. Bordeaux, CNRS, INSERM, Bordeaux Imaging Center, BIC, UMS 3420, US 4, 33000 Bordeaux, France
| | - David Perrais
- Univ. Bordeaux, CNRS, Interdisciplinary Institute for Neuroscience, IINS, UMR 5297, 33000 Bordeaux, France.
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Sauvola CW, Littleton JT. SNARE Regulatory Proteins in Synaptic Vesicle Fusion and Recycling. Front Mol Neurosci 2021; 14:733138. [PMID: 34421538 PMCID: PMC8377282 DOI: 10.3389/fnmol.2021.733138] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2021] [Accepted: 07/20/2021] [Indexed: 01/01/2023] Open
Abstract
Membrane fusion is a universal feature of eukaryotic protein trafficking and is mediated by the soluble N-ethylmaleimide sensitive factor attachment protein receptor (SNARE) family. SNARE proteins embedded in opposing membranes spontaneously assemble to drive membrane fusion and cargo exchange in vitro. Evolution has generated a diverse complement of SNARE regulatory proteins (SRPs) that ensure membrane fusion occurs at the right time and place in vivo. While a core set of SNAREs and SRPs are common to all eukaryotic cells, a specialized set of SRPs within neurons confer additional regulation to synaptic vesicle (SV) fusion. Neuronal communication is characterized by precise spatial and temporal control of SNARE dynamics within presynaptic subdomains specialized for neurotransmitter release. Action potential-elicited Ca2+ influx at these release sites triggers zippering of SNAREs embedded in the SV and plasma membrane to drive bilayer fusion and release of neurotransmitters that activate downstream targets. Here we discuss current models for how SRPs regulate SNARE dynamics and presynaptic output, emphasizing invertebrate genetic findings that advanced our understanding of SRP regulation of SV cycling.
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Affiliation(s)
- Chad W Sauvola
- The Picower Institute for Learning and Memory, Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA, United States
| | - J Troy Littleton
- The Picower Institute for Learning and Memory, Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA, United States.,Department of Biology, Massachusetts Institute of Technology, Cambridge, MA, United States
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Bera M, Ramakrishnan S, Coleman J, Krishnakumar SS, Rothman JE. Molecular Determinants of Complexin Clamping in Reconstituted Single-Vesicle Fusion.. [DOI: 10.1101/2021.07.05.451112] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
ABSTRACTPreviously we reported that Synaptotagmin-1 and Complexin synergistically clamp the SNARE assembly process to generate and maintain a pool of docked vesicles that fuse rapidly and synchronously upon Ca2+ influx (Ramakrishnan et al. 2020). Here using the same in vitro single-vesicle fusion assay, we establish the molecular details of the Complexin clamp and its physiological relevance. We find that a delay in fusion kinetics, likely imparted by Synaptotagmin-1, is needed for Complexin to block fusion. Systematic truncation/mutational analyses reveal that continuous alpha-helical accessory-central domains of Complexin are essential for its inhibitory function and specific interaction of the accessory helix with the SNAREpins, analogous to the trans clamping model, enhances this functionality. The c-terminal domain promotes clamping by locally elevating Complexin concentration through interactions with the membrane. Further, we find that Complexin likely contributes to rapid Ca2+-synchronized vesicular release by preventing un-initiated fusion rather than by directly facilitating vesicle fusion.
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43
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Wang QW, Wang YH, Wang B, Chen Y, Lu SY, Yao J. Synaptotagmin-7-mediated activation of spontaneous NMDAR currents is disrupted in bipolar disorder susceptibility variants. PLoS Biol 2021; 19:e3001323. [PMID: 34228711 PMCID: PMC8284830 DOI: 10.1371/journal.pbio.3001323] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2020] [Revised: 07/16/2021] [Accepted: 06/15/2021] [Indexed: 11/19/2022] Open
Abstract
Synaptotagmin-7 (Syt7) plays direct or redundant Ca2+ sensor roles in multiple forms of vesicle exocytosis in synapses. Here, we show that Syt7 is a redundant Ca2+ sensor with Syt1/Doc2 to drive spontaneous glutamate release, which functions uniquely to activate the postsynaptic GluN2B-containing NMDARs that significantly contribute to mental illness. In mouse hippocampal neurons lacking Syt1/Doc2, Syt7 inactivation largely diminishes spontaneous release. Using 2 approaches, including measuring Ca2+ dose response and substituting extracellular Ca2+ with Sr2+, we detect that Syt7 directly triggers spontaneous release via its Ca2+ binding motif to activate GluN2B-NMDARs. Furthermore, modifying the localization of Syt7 in the active zone still allows Syt7 to drive spontaneous release, but the GluN2B-NMDAR activity is abolished. Finally, Syt7 SNPs identified in bipolar disorder patients destroy the function of Syt7 in spontaneous release in patient iPSC-derived and mouse hippocampal neurons. Therefore, Syt7 could contribute to neuropsychiatric disorders through driving spontaneous glutamate release.
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Affiliation(s)
- Qiu-Wen Wang
- State Key Laboratory of Membrane Biology, Tsinghua-Peking Center for Life Sciences, IDG/McGovern Institute for Brain Research, School of Life Sciences, Tsinghua University, Beijing, China
| | - Ying-Han Wang
- State Key Laboratory of Membrane Biology, Tsinghua-Peking Center for Life Sciences, IDG/McGovern Institute for Brain Research, School of Life Sciences, Tsinghua University, Beijing, China
| | - Bing Wang
- State Key Laboratory of Membrane Biology, Tsinghua-Peking Center for Life Sciences, IDG/McGovern Institute for Brain Research, School of Life Sciences, Tsinghua University, Beijing, China
| | - Yun Chen
- State Key Laboratory of Membrane Biology, Tsinghua-Peking Center for Life Sciences, IDG/McGovern Institute for Brain Research, School of Life Sciences, Tsinghua University, Beijing, China
| | - Si-Yao Lu
- State Key Laboratory of Membrane Biology, Tsinghua-Peking Center for Life Sciences, IDG/McGovern Institute for Brain Research, School of Life Sciences, Tsinghua University, Beijing, China
| | - Jun Yao
- State Key Laboratory of Membrane Biology, Tsinghua-Peking Center for Life Sciences, IDG/McGovern Institute for Brain Research, School of Life Sciences, Tsinghua University, Beijing, China
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Abstract
SNARE proteins and Sec1/Munc18 (SM) proteins constitute the core molecular engine that drives nearly all intracellular membrane fusion and exocytosis. While SNAREs are known to couple their folding and assembly to membrane fusion, the physiological pathways of SNARE assembly and the mechanistic roles of SM proteins have long been enigmatic. Here, we review recent advances in understanding the SNARE-SM fusion machinery with an emphasis on biochemical and biophysical studies of proteins that mediate synaptic vesicle fusion. We begin by discussing the energetics, pathways, and kinetics of SNARE folding and assembly in vitro. Then, we describe diverse interactions between SM and SNARE proteins and their potential impact on SNARE assembly in vivo. Recent work provides strong support for the idea that SM proteins function as chaperones, their essential role being to enable fast, accurate SNARE assembly. Finally, we review the evidence that SM proteins collaborate with other SNARE chaperones, especially Munc13-1, and briefly discuss some roles of SNARE and SM protein deficiencies in human disease.
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Affiliation(s)
- Yongli Zhang
- Department of Cell Biology, Yale University School of Medicine, New Haven, Connecticut 06520, USA;
| | - Frederick M Hughson
- Department of Molecular Biology, Princeton University, Princeton, New Jersey 08544, USA;
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45
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Shvarts-Serebro I, Sheinin A, Gottfried I, Adler L, Schottlender N, Ashery U, Barak B. miR-128 as a Regulator of Synaptic Properties in 5xFAD Mice Hippocampal Neurons. J Mol Neurosci 2021; 71:2593-2607. [PMID: 34151409 DOI: 10.1007/s12031-021-01862-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2021] [Accepted: 05/25/2021] [Indexed: 10/21/2022]
Abstract
Alzheimer's disease (AD) is characterized by progressive synaptic dysfunction, deterioration of neuronal transmission, and consequently neuronal death. Although there is no treatment for AD, exposure to enriched environment (EE) in mice, as well as physical and mental activity in human subjects have been shown to have a protective effect by slowing the disease's progression and reducing AD-like cognitive impairment. However, the molecular mechanism of this mitigating effect is still not understood. One of the mechanisms that has recently been shown to be involved in neuronal degeneration is microRNAs (miRNAs) regulation, which act as a post-transcriptional regulators of gene expression. miR-128 has been shown to be significantly altered in individuals with AD and in mice following exposure to EE. Here, we focused on elucidating the possible role of miR-128 in AD pathology and found that miR-128 regulates the expression of two proteins essential for synaptic transmission, SNAP-25, and synaptotagmin1 (Syt1). Clinically relevant, in 5xFAD mouse model for AD, this miRNA's expression was found as downregulated, resembling the alteration found in the hippocampi of individuals with AD. Interestingly, exposing WT mice to EE also resulted in downregulation of miR-128 expression levels, although EE and AD conditions demonstrate opposing effects on neuronal functioning and synaptic plasticity. We also found that miR-128 expression downregulation in primary hippocampal cultures from 5xFAD mice results in increased neuronal network activity and neuronal excitability. Altogether, our findings place miR-128 as a synaptic player that may contribute to synaptic functioning and plasticity through regulation of synaptic protein expression and function.
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Affiliation(s)
| | - Anton Sheinin
- The Sagol School of Neuroscience, Tel Aviv University, Tel Aviv, Israel
| | - Irit Gottfried
- The School of Neurobiology, Biochemistry and Biophysics, Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel
| | - Lior Adler
- The Sagol School of Neuroscience, Tel Aviv University, Tel Aviv, Israel
| | - Nofar Schottlender
- The Sagol School of Neuroscience, Tel Aviv University, Tel Aviv, Israel.,The School of Neurobiology, Biochemistry and Biophysics, Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel
| | - Uri Ashery
- The Sagol School of Neuroscience, Tel Aviv University, Tel Aviv, Israel. .,The School of Neurobiology, Biochemistry and Biophysics, Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel.
| | - Boaz Barak
- The Sagol School of Neuroscience, Tel Aviv University, Tel Aviv, Israel. .,The School of Psychological Sciences, Tel Aviv University, Tel Aviv, Israel.
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46
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Blank U, Huang H, Kawakami T. The high affinity IgE receptor: a signaling update. Curr Opin Immunol 2021; 72:51-58. [PMID: 33838574 DOI: 10.1016/j.coi.2021.03.015] [Citation(s) in RCA: 35] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2021] [Accepted: 03/22/2021] [Indexed: 01/01/2023]
Abstract
Here we update receptor proximal and distant signaling events of the mast cell high affinity IgE receptor (FcεRI) launching immediate type I hypersensitivity and an inflammatory cytokine-chemokine cascade. Different physiologic antigen concentrations, their affinity, and valency for the IgE ligand produce distinct intracellular signaling events with different outcomes. Investigating mast cell degranulation has revealed a complex molecular machinery that relays proximal signaling to cytoskeletal reorganization, granule transport and membrane fusion. Several new phosphorylation- and calcium-responsive effectors have been described. FcεRI signaling also promotes de novo gene transcription. Recent progress has identified enhancers at genes that are upregulated in mast cells after stimulation through FcεRI using next generation sequencing methods. Enhancers at genes that respond to antigenic stimulation in human mast cells revealed Ca2+-dependency. Stimulation-responsive super enhancers in mouse mast cells have also been identified. Mast cell lineage-determining transcription factor GATA2 primes these enhancers to respond to antigenic stimulation.
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Affiliation(s)
- Ulrich Blank
- Université de Paris, Centre de Recherche sur l'Inflammation, INSERM UMR1149, CNRS ERL8252, Faculté de Médecine site Bichat, Paris, France; Laboratoire d'Excellence Inflamex, Paris, France.
| | - Hua Huang
- Department of Immunology and Genomic Medicine, National Jewish Health, Denver, CO 80206, USA; Department of Immunology and Microbiology, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Toshiaki Kawakami
- Laboratory of Allergic Diseases, Center for Autoimmunity and Inflammation, La Jolla Institute for Immunology, La Jolla, CA 92037, USA; Department of Dermatology, School of Medicine, University of California San Diego, La Jolla, CA 92093, USA
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47
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Ménasché G, Longé C, Bratti M, Blank U. Cytoskeletal Transport, Reorganization, and Fusion Regulation in Mast Cell-Stimulus Secretion Coupling. Front Cell Dev Biol 2021; 9:652077. [PMID: 33796537 PMCID: PMC8007931 DOI: 10.3389/fcell.2021.652077] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2021] [Accepted: 02/03/2021] [Indexed: 01/16/2023] Open
Abstract
Mast cells are well known for their role in allergies and many chronic inflammatory diseases. They release upon stimulation, e.g., via the IgE receptor, numerous bioactive compounds from cytoplasmic secretory granules. The regulation of granule secretion and its interaction with the cytoskeleton and transport mechanisms has only recently begun to be understood. These studies have provided new insight into the interaction between the secretory machinery and cytoskeletal elements in the regulation of the degranulation process. They suggest a tight coupling of these two systems, implying a series of specific signaling effectors and adaptor molecules. Here we review recent knowledge describing the signaling events regulating cytoskeletal reorganization and secretory granule transport machinery in conjunction with the membrane fusion machinery that occur during mast cell degranulation. The new insight into MC biology offers novel strategies to treat human allergic and inflammatory diseases targeting the late steps that affect harmful release from granular stores leaving regulatory cytokine secretion intact.
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Affiliation(s)
- Gaël Ménasché
- Laboratory of Molecular Basis of Altered Immune Homeostasis, Imagine Institute, INSERM UMR 1163, Université de Paris, Paris, France
| | - Cyril Longé
- Laboratory of Molecular Basis of Altered Immune Homeostasis, Imagine Institute, INSERM UMR 1163, Université de Paris, Paris, France
| | - Manuela Bratti
- Centre de Recherche sur l'Inflammation, INSERM UMR 1149, CNRS ERL8252, Faculté de Médecine site Bichat, Université de Paris, Paris, France.,Laboratoire d'Excellence Inflamex, Université de Paris, Paris, France
| | - Ulrich Blank
- Centre de Recherche sur l'Inflammation, INSERM UMR 1149, CNRS ERL8252, Faculté de Médecine site Bichat, Université de Paris, Paris, France.,Laboratoire d'Excellence Inflamex, Université de Paris, Paris, France
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48
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A unique C2 domain at the C terminus of Munc13 promotes synaptic vesicle priming. Proc Natl Acad Sci U S A 2021; 118:2016276118. [PMID: 33836576 DOI: 10.1073/pnas.2016276118] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
Neurotransmitter release during synaptic transmission comprises a tightly orchestrated sequence of molecular events, and Munc13-1 is a cornerstone of the fusion machinery. A forward genetic screen for defects in neurotransmitter release in Caenorhabditis elegans identified a mutation in the Munc13-1 ortholog UNC-13 that eliminated its unique and deeply conserved C-terminal module (referred to as HC2M) containing a Ca2+-insensitive C2 domain flanked by membrane-binding helices. The HC2M module could be functionally replaced in vivo by protein domains that localize to synaptic vesicles but not to the plasma membrane. HC2M is broadly conserved in other Unc13 family members and is required for efficient synaptic vesicle priming. We propose that the HC2M domain evolved as a vesicle/endosome adaptor and acquired synaptic vesicle specificity in the Unc13ABC protein family.
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49
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Function of Drosophila Synaptotagmins in membrane trafficking at synapses. Cell Mol Life Sci 2021; 78:4335-4364. [PMID: 33619613 PMCID: PMC8164606 DOI: 10.1007/s00018-021-03788-9] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2020] [Revised: 01/29/2021] [Accepted: 02/09/2021] [Indexed: 12/13/2022]
Abstract
The Synaptotagmin (SYT) family of proteins play key roles in regulating membrane trafficking at neuronal synapses. Using both Ca2+-dependent and Ca2+-independent interactions, several SYT isoforms participate in synchronous and asynchronous fusion of synaptic vesicles (SVs) while preventing spontaneous release that occurs in the absence of stimulation. Changes in the function or abundance of the SYT1 and SYT7 isoforms alter the number and route by which SVs fuse at nerve terminals. Several SYT family members also regulate trafficking of other subcellular organelles at synapses, including dense core vesicles (DCV), exosomes, and postsynaptic vesicles. Although SYTs are linked to trafficking of multiple classes of synaptic membrane compartments, how and when they interact with lipids, the SNARE machinery and other release effectors are still being elucidated. Given mutations in the SYT family cause disorders in both the central and peripheral nervous system in humans, ongoing efforts are defining how these proteins regulate vesicle trafficking within distinct neuronal compartments. Here, we review the Drosophila SYT family and examine their role in synaptic communication. Studies in this invertebrate model have revealed key similarities and several differences with the predicted activity of their mammalian counterparts. In addition, we highlight the remaining areas of uncertainty in the field and describe outstanding questions on how the SYT family regulates membrane trafficking at nerve terminals.
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50
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Belalcazar HM, Hendricks EL, Zamurrad S, Liebl FLW, Secombe J. The histone demethylase KDM5 is required for synaptic structure and function at the Drosophila neuromuscular junction. Cell Rep 2021; 34:108753. [PMID: 33596422 PMCID: PMC7945993 DOI: 10.1016/j.celrep.2021.108753] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2020] [Revised: 12/14/2020] [Accepted: 01/25/2021] [Indexed: 02/08/2023] Open
Abstract
Mutations in the genes encoding the lysine demethylase 5 (KDM5) family of histone demethylases are observed in individuals with intellectual disability (ID). Despite clear evidence linking KDM5 function to neurodevelopmental pathways, how this family of proteins impacts transcriptional programs to mediate synaptic structure and activity remains unclear. Using the Drosophila larval neuromuscular junction (NMJ), we show that KDM5 is required presynaptically for neuroanatomical development and synaptic function. The Jumonji C (JmjC) domain-encoded histone demethylase activity of KDM5, which is expected to be diminished by many ID-associated alleles, is required for appropriate synaptic morphology and neurotransmission. The activity of the C5HC2 zinc finger is also required, as an ID-associated mutation in this motif reduces NMJ bouton number, increases bouton size, and alters microtubule dynamics. KDM5 therefore uses demethylase-dependent and independent mechanisms to regulate NMJ structure and activity, highlighting the complex nature by which this chromatin modifier carries out its neuronal gene-regulatory programs.
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Affiliation(s)
- Helen M Belalcazar
- Department of Genetics, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, NY 10461, USA
| | - Emily L Hendricks
- Department of Biological Sciences, Southern Illinois University Edwardsville, 44 Circle Drive, Edwardsville, IL 62026, USA
| | - Sumaira Zamurrad
- Department of Genetics, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, NY 10461, USA
| | - Faith L W Liebl
- Department of Biological Sciences, Southern Illinois University Edwardsville, 44 Circle Drive, Edwardsville, IL 62026, USA
| | - Julie Secombe
- Department of Genetics, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, NY 10461, USA; Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, 1410 Pelham Parkway South, Bronx, NY 10461, USA.
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