The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
Thomas C. Südhof - One of the best experts on this subject based on the ideXlab platform.
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the morphological and molecular nature of Synaptic Vesicle priming at preSynaptic active zones
Neuron, 2014Co-Authors: Cordelia Imig, Nils Brose, Sang-won Min, Marife Arancillo, Thomas C. Südhof, Christian Rosenmund, Stefanie Krinner, Jeongseop Rhee, Benjamin H CooperAbstract:Synaptic Vesicle docking, priming, and fusion at active zones are orchestrated by a complex molecular machinery. We employed hippocampal organotypic slice cultures from mice lacking key preSynaptic proteins, cryofixation, and three-dimensional electron tomography to study the mechanism of Synaptic Vesicle docking in the same experimental setting, with high precision, and in a near-native state. We dissected previously indistinguishable, sequential steps in Synaptic Vesicle active zone recruitment (tethering) and membrane attachment (docking) and found that Vesicle docking requires Munc13/CAPS family priming proteins and all three neuronal SNAREs, but not Synaptotagmin-1 or Complexins. Our data indicate that membrane-attached Vesicles comprise the readily releasable pool of fusion-competent Vesicles and that Synaptic Vesicle docking, priming, and trans-SNARE complex assembly are the respective morphological, functional, and molecular manifestations of the same process, which operates downstream of Vesicle tethering by active zone components.
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Syntaxin-1 N-peptide and Habc-domain perform distinct essential functions in Synaptic Vesicle fusion
The EMBO Journal, 2012Co-Authors: Peng Zhou, Zhiping P. Pang, Xiaofei Yang, Yingsha Zhang, Christian Rosenmund, Taulant Bacaj, Thomas C. SüdhofAbstract:Among SNARE proteins mediating Synaptic Vesicle fusion, syntaxin-1 uniquely includes an N-terminal peptide (‘Npeptide’) that binds to Munc18-1, and a large, conserved Habc-domain that also binds to Munc18-1. Previous in vitro studies suggested that the syntaxin-1 N-peptide is functionally important, whereas the syntaxin-1 Habc-domain is not, but limited information is available about the in vivo functions of these syntaxin-1 domains. Using rescue experiments in cultured syntaxin-deficient neurons, we now show that the N-peptide and the Habc-domain of syntaxin1 perform distinct and independent roles in Synaptic Vesicle fusion. Specifically, we found that the N-peptide is essential for Vesicle fusion as such, whereas the Habc-domain regulates this fusion, in part by forming the closed syntaxin-1 conformation. Moreover, we observed that deletion of the Habc-domain but not deletion of the N-peptide caused a loss of Munc18-1 which results in a decrease in the readily releasable pool of Vesicles at a synapse, suggesting that Munc18 binding to the Habc-domain stabilizes Munc18-1. Thus, the N-terminal syntaxin-1 domains mediate different functions in Synaptic Vesicle fusion, probably via formation of distinct Munc18/SNARE-protein complexes.
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Synaptic Vesicle exocytosis
Cold Spring Harbor Perspectives in Biology, 2011Co-Authors: Thomas C. Südhof, Josep RizoAbstract:PreSynaptic nerve terminals release neurotransmitters by Synaptic Vesicle exocytosis. Membrane fusion mediating Synaptic exocytosis and other intracellular membrane traffic is affected by a universal machinery that includes SNARE (for "soluble NSF-attachment protein receptor") and SM (for "Sec1/Munc18-like") proteins. During fusion, vesicular and target SNARE proteins assemble into an α-helical trans-SNARE complex that forces the two membranes tightly together, and SM proteins likely wrap around assembling trans-SNARE complexes to catalyze membrane fusion. After fusion, SNARE complexes are dissociated by the ATPase NSF (for "N-ethylmaleimide sensitive factor"). Fusion-competent conformations of SNARE proteins are maintained by chaperone complexes composed of CSPα, Hsc70, and SGT, and by nonenzymatically acting synuclein chaperones; dysfunction of these chaperones results in neurodegeneration. The Synaptic membrane-fusion machinery is controlled by synaptotagmin, and additionally regulated by a preSynaptic protein matrix (the "active zone") that includes Munc13 and RIM proteins as central components.
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structural determinants of synaptobrevin 2 function in Synaptic Vesicle fusion
The Journal of Neuroscience, 2006Co-Authors: Ferenc Deak, Thomas C. Südhof, Ok Ho Shin, Ege T KavalaliAbstract:Deletion of synaptobrevin/Vesicle-associated membrane protein, the major Synaptic Vesicle soluble N-ethylmaleimide-sensitive factor attachment protein receptor (R-SNARE), severely decreases but does not abolish spontaneous and evoked Synaptic Vesicle exocytosis. We now show that the closely related R-SNARE protein cellubrevin rescues Synaptic transmission in synaptobrevin-deficient neurons but that deletion of both cellubrevin and synaptobrevin does not cause a more severe decrease in exocytosis than deletion of synaptobrevin alone. We then examined the structural requirements for synaptobrevin to function in exocytosis. We found that substituting glutamine for arginine in the zero-layer of the SNARE motif did not significantly impair synaptobrevin-dependent exocytosis, whereas insertion of 12 or 24 residues between the SNARE motif and transmembrane region abolished the ability of synaptobrevin to mediate Ca2+-evoked exocytosis. Surprisingly, however, synaptobrevin with the 12-residue but not the 24-residue insertion restored spontaneous release in synaptobrevin-deficient neurons. Our data suggest that synaptobrevin mediates Ca2+-triggered exocytosis by tight coupling of the SNARE motif to the transmembrane region and hence forcing the membranes into close proximity for fusion. Furthermore, the fusion reactions underlying evoked and spontaneous release differ mechanistically.
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snares and munc18 in Synaptic Vesicle fusion
Nature Reviews Neuroscience, 2002Co-Authors: Josep Rizo, Thomas C. SüdhofAbstract:The release of neurotransmitters by Ca2+-triggered Synaptic Vesicle exocytosis is an exquisitely regulated process that is fundamental for interneuronal communication. This process involves several steps and is controlled by a protein machinery that must prevent release before Ca2+ entry into preSynaptic terminals, and yet must rapidly induce release on Ca2+ influx. Extensive studies of the components of this machinery have indicated that SNAREs and Munc18-1 are central proteins for membrane fusion during exocytosis. An increasing amount of information derived from a convergence of structural, physiological and genetic studies is providing important insights into the mechanism of neurotransmitter release.
Nils Brose - One of the best experts on this subject based on the ideXlab platform.
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Synaptic Vesicle fusion: today and beyond
Nature Structural & Molecular Biology, 2019Co-Authors: Nils Brose, Axel T. Brunger, David S. Cafiso, Edwin R. Chapman, Jiajie Diao, Frederick M. Hughson, Meyer B. Jackson, Reinhard Jahn, Manfred LindauAbstract:Researchers working on Synaptic Vesicle fusion and neurotransmitter release share their views on the most interesting developments in their field and the challenges that lie ahead.
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dynamically primed Synaptic Vesicle states key to understand Synaptic short term plasticity
Neuron, 2018Co-Authors: Erwin Neher, Nils BroseAbstract:Summary Based on evidence that the docked and primed Synaptic Vesicle state is very dynamic, we propose a three-step process for the buildup of the molecular machinery that mediates Synaptic Vesicle fusion: (1) loose tethering and docking of Vesicles to release sites, forming the nucleus of SNARE-complex assembly, (2) tightening of the complex by association of additional proteins, and partial SNARE-complex zippering, and (3) Ca2+-triggered fusion. We argue that the distinction between “phasic synapses” and “tonic synapses” reflects differences in resting occupancy and stability of the loosely and tightly docked states, and we assign corresponding timescales: with high-frequency Synaptic activity and concomitantly increased Ca2+-concentrations, step (1) can proceed within 10–50 ms, step (2) within 1–5 ms, and step (3) within 0.2–1 ms.
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the morphological and molecular nature of Synaptic Vesicle priming at preSynaptic active zones
Neuron, 2014Co-Authors: Cordelia Imig, Nils Brose, Sang-won Min, Marife Arancillo, Thomas C. Südhof, Christian Rosenmund, Stefanie Krinner, Jeongseop Rhee, Benjamin H CooperAbstract:Synaptic Vesicle docking, priming, and fusion at active zones are orchestrated by a complex molecular machinery. We employed hippocampal organotypic slice cultures from mice lacking key preSynaptic proteins, cryofixation, and three-dimensional electron tomography to study the mechanism of Synaptic Vesicle docking in the same experimental setting, with high precision, and in a near-native state. We dissected previously indistinguishable, sequential steps in Synaptic Vesicle active zone recruitment (tethering) and membrane attachment (docking) and found that Vesicle docking requires Munc13/CAPS family priming proteins and all three neuronal SNAREs, but not Synaptotagmin-1 or Complexins. Our data indicate that membrane-attached Vesicles comprise the readily releasable pool of fusion-competent Vesicles and that Synaptic Vesicle docking, priming, and trans-SNARE complex assembly are the respective morphological, functional, and molecular manifestations of the same process, which operates downstream of Vesicle tethering by active zone components.
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snare protein recycling by αsnap and βsnap supports Synaptic Vesicle priming
Neuron, 2010Co-Authors: Andrea Burgalossi, Sangyong Jung, Guido Meyer, Wolf J Jockusch, Olaf Jahn, Holger Taschenberger, Vincent Oconnor, Teiichi Nishiki, Masami Takahashi, Nils BroseAbstract:Neurotransmitter release proceeds by Ca(2+)-triggered, SNARE-complex-dependent Synaptic Vesicle fusion. After fusion, the ATPase NSF and its cofactors α- and βSNAP disassemble SNARE complexes, thereby recycling individual SNAREs for subsequent fusion reactions. We examined the effects of genetic perturbation of α- and βSNAP expression on Synaptic Vesicle exocytosis, employing a new Ca(2+) uncaging protocol to study Synaptic Vesicle trafficking, priming, and fusion in small glutamatergic synapses of hippocampal neurons. By characterizing this protocol, we show that synchronous and asynchronous transmitter release involve different Ca(2+) sensors and are not caused by distinct releasable Vesicle pools, and that tonic transmitter release is due to ongoing priming and fusion of new Synaptic Vesicles during high Synaptic activity. Our analysis of α- and βSNAP deletion mutant neurons shows that the two NSF cofactors support Synaptic Vesicle priming by determining the availability of free SNARE components, particularly during phases of high Synaptic activity.
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caps 1 and caps 2 are essential Synaptic Vesicle priming proteins
Cell, 2007Co-Authors: Wolf J Jockusch, Jeongseop Rhee, Dina Speidel, Albrecht Sigler, Jakob B Sorensen, Frederique Varoqueaux, Nils BroseAbstract:Before transmitter-filled Synaptic Vesicles can fuse with the plasma membrane upon stimulation they have to be primed to fusion competence. The regulation of this priming process controls the strength and plasticity of Synaptic transmission between neurons, which in turn determines many complex brain functions. We show that CAPS-1 and CAPS-2 are essential components of the Synaptic Vesicle priming machinery. CAPS-deficient neurons contain no or very few fusion competent Synaptic Vesicles, which causes a selective impairment of fast phasic transmitter release. Increases in the intracellular Ca 2+ levels can transiently revert this defect. Our findings demonstrate that CAPS proteins generate and maintain a highly fusion competent Synaptic Vesicle pool that supports phasic Ca 2+ triggered release of transmitters.
Josep Rizo - One of the best experts on this subject based on the ideXlab platform.
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syntaxin opening by the mun domain underlies the function of munc13 in Synaptic Vesicle priming
Nature Structural & Molecular Biology, 2015Co-Authors: Xiaoyu Yang, Josep Rizo, Shen Wang, Yi Sheng, Mingshu Zhang, Wenjuan Zou, Lijun Kang, Rongguang ZhangAbstract:Crystallographic and functional studies reveal the arch-shaped architecture of the Munc13 MUN domain and show the molecular basis for Munc13's role in Synaptic-Vesicle priming by mediating syntaxin-1 opening and SNARE-complex assembly.
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Synaptic Vesicle exocytosis
Cold Spring Harbor Perspectives in Biology, 2011Co-Authors: Thomas C. Südhof, Josep RizoAbstract:PreSynaptic nerve terminals release neurotransmitters by Synaptic Vesicle exocytosis. Membrane fusion mediating Synaptic exocytosis and other intracellular membrane traffic is affected by a universal machinery that includes SNARE (for "soluble NSF-attachment protein receptor") and SM (for "Sec1/Munc18-like") proteins. During fusion, vesicular and target SNARE proteins assemble into an α-helical trans-SNARE complex that forces the two membranes tightly together, and SM proteins likely wrap around assembling trans-SNARE complexes to catalyze membrane fusion. After fusion, SNARE complexes are dissociated by the ATPase NSF (for "N-ethylmaleimide sensitive factor"). Fusion-competent conformations of SNARE proteins are maintained by chaperone complexes composed of CSPα, Hsc70, and SGT, and by nonenzymatically acting synuclein chaperones; dysfunction of these chaperones results in neurodegeneration. The Synaptic membrane-fusion machinery is controlled by synaptotagmin, and additionally regulated by a preSynaptic protein matrix (the "active zone") that includes Munc13 and RIM proteins as central components.
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Conformational Switch of Syntaxin-1 Controls Synaptic Vesicle Fusion
Science, 2008Co-Authors: Stefan H. Gerber, Jong-cheol Rah, Sang-won Min, Xinran Liu, Heidi De Wit, Irina Dulubova, Alexander C. Meyer, Josep Rizo, Marife Arancillo, Robert E. HammerAbstract:During Synaptic Vesicle fusion, the soluble N-ethylmaleimide-sensitive factor-attachment protein receptor (SNARE) protein syntaxin-1 exhibits two conformations that both bind to Munc18-1: a "closed" conformation outside the SNARE complex and an "open" conformation in the SNARE complex. Although SNARE complexes containing open syntaxin-1 and Munc18-1 are essential for exocytosis, the function of closed syntaxin-1 is unknown. We generated knockin/knockout mice that expressed only open syntaxin-1B. Syntaxin-1B(Open) mice were viable but succumbed to generalized seizures at 2 to 3 months of age. Binding of Munc18-1 to syntaxin-1 was impaired in syntaxin-1B(Open) synapses, and the size of the readily releasable Vesicle pool was decreased; however, the rate of Synaptic Vesicle fusion was dramatically enhanced. Thus, the closed conformation of syntaxin-1 gates the initiation of the Synaptic Vesicle fusion reaction, which is then mediated by SNARE-complex/Munc18-1 assemblies.
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snares and munc18 in Synaptic Vesicle fusion
Nature Reviews Neuroscience, 2002Co-Authors: Josep Rizo, Thomas C. SüdhofAbstract:The release of neurotransmitters by Ca2+-triggered Synaptic Vesicle exocytosis is an exquisitely regulated process that is fundamental for interneuronal communication. This process involves several steps and is controlled by a protein machinery that must prevent release before Ca2+ entry into preSynaptic terminals, and yet must rapidly induce release on Ca2+ influx. Extensive studies of the components of this machinery have indicated that SNAREs and Munc18-1 are central proteins for membrane fusion during exocytosis. An increasing amount of information derived from a convergence of structural, physiological and genetic studies is providing important insights into the mechanism of neurotransmitter release.
Reinhard Jahn - One of the best experts on this subject based on the ideXlab platform.
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Synaptic Vesicle fusion: today and beyond
Nature Structural & Molecular Biology, 2019Co-Authors: Nils Brose, Axel T. Brunger, David S. Cafiso, Edwin R. Chapman, Jiajie Diao, Frederick M. Hughson, Meyer B. Jackson, Reinhard Jahn, Manfred LindauAbstract:Researchers working on Synaptic Vesicle fusion and neurotransmitter release share their views on the most interesting developments in their field and the challenges that lie ahead.
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elevated Synaptic Vesicle release probability in synaptophysin gyrin family quadruple knockouts
eLife, 2019Co-Authors: Mathan K Raja, Reinhard Jahn, Julia Preobraschenski, Sergio Del Olmocabrera, Rebeca Martinezturrillas, Isabel Perezotano, John F WesselingAbstract:Synaptophysins 1 and 2 and synaptogyrins 1 and 3 constitute a major family of Synaptic Vesicle membrane proteins. Unlike other widely expressed Synaptic Vesicle proteins such as vSNAREs and synaptotagmins, the primary function has not been resolved. Here, we report robust elevation in the probability of release of readily releasable Vesicles with both high and low release probabilities at a variety of synapse types from knockout mice missing all four family members. Neither the number of readily releasable Vesicles, nor the timing of recruitment to the readily releasable pool was affected. The results suggest that family members serve as negative regulators of neurotransmission, acting directly at the level of exocytosis to dampen connection strength selectively when preSynaptic action potentials fire at low frequency. The widespread expression suggests that chemical synapses may play a frequency filtering role in biological computation that is more elemental than presently envisioned. Editorial note: This article has been through an editorial process in which the authors decide how to respond to the issues raised during peer review. The Reviewing Editor's assessment is that all the issues have been addressed (see decision letter).
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sted microscopy reveals that synaptotagmin remains clustered after Synaptic Vesicle exocytosis
Nature, 2006Co-Authors: Katrin I Willig, Reinhard Jahn, Silvio O. Rizzoli, Volker Westphal, Stefan W HellAbstract:STED microscopy reveals that synaptotagmin remains clustered after Synaptic Vesicle exocytosis
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Synaptic targeting of rabphilin 3a a Synaptic Vesicle ca2 phospholipid binding protein depends on rab3a 3c
Neuron, 1994Co-Authors: Kohji Takei, Pietro De Camilli, Edwin R. Chapman, Reinhard Jahn, Martin Geppert, Laurie Daniell, Katinka Stenius, Thomas C. SüdhofAbstract:Abstract rab3A, a low molecular weight GTP-binding protein of Synaptic Vesicles with a putative function in Synaptic Vesicle docking, interacts in a GTP-dependent manner with rabphilin-3A, a peripheral membrane protein that binds Call and phospholipids. We now show that rabphilin-3A is an evolutionarily conserved Synaptic Vesicle protein that is attached to Synaptic Vesicle membranes via its N terminus and exhibits a heterogeneous distribution among synapses. In rab3A-deficient mice, rabphilin-3A is decreased in synapses belonging to neurons that primarily express rab3A and accumulates in the perikarya of these neurons. In contrast, neurons expressing significant levels of rab3C still contain normal levels of rabphilin-3A in a Synaptic pattern, and rabphilin-3A binds rab3C in vitro. These results suggest that analogous to the membrane recruitment of raf by ras, rab3A and rab3C may function in recruiting .rabphilin-3A to the Synaptic Vesicle membrane in a GTP-dependent manner.
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Clathrin-coated Vesicles in nervous tissue are involved primarily in Synaptic Vesicle recycling.
The Journal of cell biology, 1992Co-Authors: P. R. Maycox, E Link, A Reetz, S A Morris, Reinhard JahnAbstract:The recycling of Synaptic Vesicles in nerve terminals is thought to involve clathrin-coated Vesicles. However, the properties of nerve terminal coated Vesicles have not been characterized. Starting from a preparation of purified nerve terminals obtained from rat brain, we isolated clathrin-coated Vesicles by a series of differential and density gradient centrifugation steps. The enrichment of coated Vesicles during fractionation was monitored by EM. The final fraction consisted of greater than 90% of coated Vesicles, with only negligible contamination by Synaptic Vesicles. Control experiments revealed that the contribution by coated Vesicles derived from the axo-dendritic region or from nonneuronal cells is minimal. The membrane composition of nerve terminal-derived coated Vesicles was very similar to that of Synaptic Vesicles, containing the membrane proteins synaptophysin, synaptotagmin, p29, synaptobrevin and the 116-kD subunit of the vacuolar proton pump, in similar stoichiometric ratios. The small GTP-binding protein rab3A was absent, probably reflecting its dissociation from Synaptic Vesicles during endocytosis. Immunogold EM revealed that virtually all coated Vesicles carried Synaptic Vesicle proteins, demonstrating that the contribution by coated Vesicles derived from other membrane traffic pathways is negligible. Coated Vesicles isolated from the whole brain exhibited a similar composition, most of them carrying Synaptic Vesicle proteins. This indicates that in nervous tissue, coated Vesicles function predominantly in the Synaptic Vesicle pathway. Nerve terminal-derived coated Vesicles contained AP-2 adaptor complexes, which is in agreement with their plasmalemmal origin. Furthermore, the neuron-specific coat proteins AP 180 and auxilin, as well as the alpha a1 and alpha c1-adaptins, were enriched in this fraction, suggesting a function for these coat proteins in Synaptic Vesicle recycling.
John F Wesseling - One of the best experts on this subject based on the ideXlab platform.
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elevated Synaptic Vesicle release probability in synaptophysin gyrin family quadruple knockouts
eLife, 2019Co-Authors: Mathan K Raja, Reinhard Jahn, Julia Preobraschenski, Sergio Del Olmocabrera, Rebeca Martinezturrillas, Isabel Perezotano, John F WesselingAbstract:Synaptophysins 1 and 2 and synaptogyrins 1 and 3 constitute a major family of Synaptic Vesicle membrane proteins. Unlike other widely expressed Synaptic Vesicle proteins such as vSNAREs and synaptotagmins, the primary function has not been resolved. Here, we report robust elevation in the probability of release of readily releasable Vesicles with both high and low release probabilities at a variety of synapse types from knockout mice missing all four family members. Neither the number of readily releasable Vesicles, nor the timing of recruitment to the readily releasable pool was affected. The results suggest that family members serve as negative regulators of neurotransmission, acting directly at the level of exocytosis to dampen connection strength selectively when preSynaptic action potentials fire at low frequency. The widespread expression suggests that chemical synapses may play a frequency filtering role in biological computation that is more elemental than presently envisioned. Editorial note: This article has been through an editorial process in which the authors decide how to respond to the issues raised during peer review. The Reviewing Editor's assessment is that all the issues have been addressed (see decision letter).
