1
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Longfield SF, Gormal RS, Feller M, Parutto P, Reingruber J, Wallis TP, Joensuu M, Augustine GJ, Martínez-Mármol R, Holcman D, Meunier FA. Synapsin 2a tetramerisation selectively controls the presynaptic nanoscale organisation of reserve synaptic vesicles. Nat Commun 2024; 15:2217. [PMID: 38472171 PMCID: PMC10933366 DOI: 10.1038/s41467-024-46256-1] [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: 03/22/2023] [Accepted: 02/21/2024] [Indexed: 03/14/2024] Open
Abstract
Neurotransmitter release relies on the regulated fusion of synaptic vesicles (SVs) that are tightly packed within the presynaptic bouton of neurons. The mechanism by which SVs are clustered at the presynapse, while preserving their ability to dynamically recycle to support neuronal communication, remains unknown. Synapsin 2a (Syn2a) tetramerization has been suggested as a potential clustering mechanism. Here, we used Dual-pulse sub-diffractional Tracking of Internalised Molecules (DsdTIM) to simultaneously track single SVs from the recycling and the reserve pools, in live hippocampal neurons. The reserve pool displays a lower presynaptic mobility compared to the recycling pool and is also present in the axons. Triple knockout of Synapsin 1-3 genes (SynTKO) increased the mobility of reserve pool SVs. Re-expression of wild-type Syn2a (Syn2aWT), but not the tetramerization-deficient mutant K337Q (Syn2aK337Q), fully rescued these effects. Single-particle tracking revealed that Syn2aK337QmEos3.1 exhibited altered activity-dependent presynaptic translocation and nanoclustering. Therefore, Syn2a tetramerization controls its own presynaptic nanoclustering and thereby contributes to the dynamic immobilisation of the SV reserve pool.
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Affiliation(s)
- Shanley F Longfield
- Clem Jones Centre for Ageing Dementia Research, Queensland Brain Institute, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Rachel S Gormal
- Clem Jones Centre for Ageing Dementia Research, Queensland Brain Institute, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Matis Feller
- Group of Data Modelling and Computational Biology, IBENS, Ecole Normale Superieure, 75005, Paris, France
| | - Pierre Parutto
- Group of Data Modelling and Computational Biology, IBENS, Ecole Normale Superieure, 75005, Paris, France
| | - Jürgen Reingruber
- Group of Data Modelling and Computational Biology, IBENS, Ecole Normale Superieure, 75005, Paris, France
| | - Tristan P Wallis
- Clem Jones Centre for Ageing Dementia Research, Queensland Brain Institute, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Merja Joensuu
- Clem Jones Centre for Ageing Dementia Research, Queensland Brain Institute, The University of Queensland, Brisbane, QLD 4072, Australia
- Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, Brisbane, QLD 4072, Australia
| | | | - Ramón Martínez-Mármol
- Clem Jones Centre for Ageing Dementia Research, Queensland Brain Institute, The University of Queensland, Brisbane, QLD 4072, Australia
| | - David Holcman
- Group of Data Modelling and Computational Biology, IBENS, Ecole Normale Superieure, 75005, Paris, France
- Department of Applied Mathematics and Theoretical Physics (DAMPT) visitor, University of Cambridge, and Churchill College, CB30DS, Cambridge, UK
| | - Frédéric A Meunier
- Clem Jones Centre for Ageing Dementia Research, Queensland Brain Institute, The University of Queensland, Brisbane, QLD 4072, Australia.
- School of Biomedical Sciences, The University of Queensland, Brisbane, QLD 4072, Australia.
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2
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Sansevrino R, Hoffmann C, Milovanovic D. Condensate biology of synaptic vesicle clusters. Trends Neurosci 2023; 46:293-306. [PMID: 36725404 DOI: 10.1016/j.tins.2023.01.001] [Citation(s) in RCA: 19] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2022] [Revised: 12/20/2022] [Accepted: 01/10/2023] [Indexed: 01/31/2023]
Abstract
Neuronal communication crucially relies on exocytosis of neurotransmitters from synaptic vesicles (SVs) which are clustered at synapses. To ensure reliable neurotransmitter release, synapses need to maintain an adequate pool of SVs at all times. Decades of research have established that SVs are clustered by synapsin 1, an abundant SV-associated phosphoprotein. The classical view postulates that SVs are crosslinked in a scaffold of protein-protein interactions between synapsins and their binding partners. Recent studies have shown that synapsins cluster SVs via liquid-liquid phase separation (LLPS), thus providing a new framework for the organization of the synapse. We discuss the evidence for phase separation of SVs, emphasizing emerging questions related to its regulation, specificity, and reversibility.
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Affiliation(s)
- Roberto Sansevrino
- Laboratory of Molecular Neuroscience, German Center for Neurodegenerative Diseases (DZNE), 10117 Berlin, Germany
| | - Christian Hoffmann
- Laboratory of Molecular Neuroscience, German Center for Neurodegenerative Diseases (DZNE), 10117 Berlin, Germany
| | - Dragomir Milovanovic
- Laboratory of Molecular Neuroscience, German Center for Neurodegenerative Diseases (DZNE), 10117 Berlin, Germany.
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3
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Dankovich TM, Rizzoli SO. The Synaptic Extracellular Matrix: Long-Lived, Stable, and Still Remarkably Dynamic. Front Synaptic Neurosci 2022; 14:854956. [PMID: 35350469 PMCID: PMC8957932 DOI: 10.3389/fnsyn.2022.854956] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2022] [Accepted: 02/16/2022] [Indexed: 01/09/2023] Open
Abstract
In the adult brain, synapses are tightly enwrapped by lattices of the extracellular matrix that consist of extremely long-lived molecules. These lattices are deemed to stabilize synapses, restrict the reorganization of their transmission machinery, and prevent them from undergoing structural or morphological changes. At the same time, they are expected to retain some degree of flexibility to permit occasional events of synaptic plasticity. The recent understanding that structural changes to synapses are significantly more frequent than previously assumed (occurring even on a timescale of minutes) has called for a mechanism that allows continual and energy-efficient remodeling of the extracellular matrix (ECM) at synapses. Here, we review recent evidence for such a process based on the constitutive recycling of synaptic ECM molecules. We discuss the key characteristics of this mechanism, focusing on its roles in mediating synaptic transmission and plasticity, and speculate on additional potential functions in neuronal signaling.
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Affiliation(s)
- Tal M. Dankovich
- University Medical Center Göttingen, Institute for Neuro- and Sensory Physiology, Göttingen, Germany
- International Max Planck Research School for Neuroscience, Göttingen, Germany
- *Correspondence: Tal M. Dankovich Silvio O. Rizzoli
| | - Silvio O. Rizzoli
- University Medical Center Göttingen, Institute for Neuro- and Sensory Physiology, Göttingen, Germany
- Biostructural Imaging of Neurodegeneration (BIN) Center & Multiscale Bioimaging Excellence Center, Göttingen, Germany
- *Correspondence: Tal M. Dankovich Silvio O. Rizzoli
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4
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Dankovich TM, Kaushik R, Olsthoorn LHM, Petersen GC, Giro PE, Kluever V, Agüi-Gonzalez P, Grewe K, Bao G, Beuermann S, Hadi HA, Doeren J, Klöppner S, Cooper BH, Dityatev A, Rizzoli SO. Extracellular matrix remodeling through endocytosis and resurfacing of Tenascin-R. Nat Commun 2021; 12:7129. [PMID: 34880248 PMCID: PMC8654841 DOI: 10.1038/s41467-021-27462-7] [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: 10/27/2020] [Accepted: 11/19/2021] [Indexed: 01/22/2023] Open
Abstract
The brain extracellular matrix (ECM) consists of extremely long-lived proteins that assemble around neurons and synapses, to stabilize them. The ECM is thought to change only rarely, in relation to neuronal plasticity, through ECM proteolysis and renewed protein synthesis. We report here an alternative ECM remodeling mechanism, based on the recycling of ECM molecules. Using multiple ECM labeling and imaging assays, from super-resolution optical imaging to nanoscale secondary ion mass spectrometry, both in culture and in brain slices, we find that a key ECM protein, Tenascin-R, is frequently endocytosed, and later resurfaces, preferentially near synapses. The TNR molecules complete this cycle within ~3 days, in an activity-dependent fashion. Interfering with the recycling process perturbs severely neuronal function, strongly reducing synaptic vesicle exo- and endocytosis. We conclude that the neuronal ECM can be remodeled frequently through mechanisms that involve endocytosis and recycling of ECM proteins.
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Affiliation(s)
- Tal M. Dankovich
- grid.411984.10000 0001 0482 5331University Medical Center Göttingen, Institute for Neuro- and Sensory Physiology, Excellence Cluster Multiscale Bioimaging, Göttingen, Germany ,grid.4372.20000 0001 2105 1091International Max Planck Research School for Neuroscience, Göttingen, Germany
| | - Rahul Kaushik
- grid.424247.30000 0004 0438 0426Molecular Neuroplasticity, German Center for Neurodegenerative Diseases (DZNE), Magdeburg, Germany ,grid.418723.b0000 0001 2109 6265Center for Behavioral Brain Sciences (CBBS), Magdeburg, Germany
| | - Linda H. M. Olsthoorn
- grid.4372.20000 0001 2105 1091International Max Planck Research School for Neuroscience, Göttingen, Germany ,grid.418140.80000 0001 2104 4211Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
| | - Gabriel Cassinelli Petersen
- grid.411984.10000 0001 0482 5331University Medical Center Göttingen, Institute for Neuro- and Sensory Physiology, Excellence Cluster Multiscale Bioimaging, Göttingen, Germany
| | - Philipp Emanuel Giro
- grid.411984.10000 0001 0482 5331University Medical Center Göttingen, Institute for Neuro- and Sensory Physiology, Excellence Cluster Multiscale Bioimaging, Göttingen, Germany
| | - Verena Kluever
- grid.411984.10000 0001 0482 5331University Medical Center Göttingen, Institute for Neuro- and Sensory Physiology, Excellence Cluster Multiscale Bioimaging, Göttingen, Germany
| | - Paola Agüi-Gonzalez
- grid.411984.10000 0001 0482 5331University Medical Center Göttingen, Institute for Neuro- and Sensory Physiology, Excellence Cluster Multiscale Bioimaging, Göttingen, Germany
| | - Katharina Grewe
- grid.411984.10000 0001 0482 5331University Medical Center Göttingen, Institute for Neuro- and Sensory Physiology, Excellence Cluster Multiscale Bioimaging, Göttingen, Germany
| | - Guobin Bao
- grid.411984.10000 0001 0482 5331University Medical Center Göttingen, Institute for Neuro- and Sensory Physiology, Excellence Cluster Multiscale Bioimaging, Göttingen, Germany ,grid.411984.10000 0001 0482 5331University Medical Center Göttingen, Institute of Pharmacology and Toxicology, Göttingen, Germany
| | - Sabine Beuermann
- grid.419522.90000 0001 0668 6902Max Planck Institute for Experimental Medicine, Göttingen, Germany
| | - Hannah Abdul Hadi
- grid.411984.10000 0001 0482 5331University Medical Center Göttingen, Institute for Neuro- and Sensory Physiology, Excellence Cluster Multiscale Bioimaging, Göttingen, Germany
| | - Jose Doeren
- grid.411984.10000 0001 0482 5331University Medical Center Göttingen, Institute for Neuro- and Sensory Physiology, Excellence Cluster Multiscale Bioimaging, Göttingen, Germany
| | - Simon Klöppner
- grid.411984.10000 0001 0482 5331University Medical Center Göttingen, Institute for Neuro- and Sensory Physiology, Excellence Cluster Multiscale Bioimaging, Göttingen, Germany
| | - Benjamin H. Cooper
- grid.419522.90000 0001 0668 6902Max Planck Institute for Experimental Medicine, Göttingen, Germany
| | - Alexander Dityatev
- grid.424247.30000 0004 0438 0426Molecular Neuroplasticity, German Center for Neurodegenerative Diseases (DZNE), Magdeburg, Germany ,grid.418723.b0000 0001 2109 6265Center for Behavioral Brain Sciences (CBBS), Magdeburg, Germany ,grid.5807.a0000 0001 1018 4307Medical Faculty, Otto von Guericke University, Magdeburg, Germany
| | - Silvio O. Rizzoli
- grid.411984.10000 0001 0482 5331University Medical Center Göttingen, Institute for Neuro- and Sensory Physiology, Excellence Cluster Multiscale Bioimaging, Göttingen, Germany ,Biostructural Imaging of Neurodegeneration (BIN) Center, Göttingen, Germany
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5
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Gramlich MW, Klyachko VA. Nanoscale Organization of Vesicle Release at Central Synapses. Trends Neurosci 2020; 42:425-437. [PMID: 31176424 DOI: 10.1016/j.tins.2019.03.001] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2019] [Revised: 02/20/2019] [Accepted: 03/01/2019] [Indexed: 11/28/2022]
Abstract
Presynaptic boutons support neurotransmitter release with nanoscale precision at sub-millisecond timescales. Studies over the past two decades have revealed a rich tapestry of molecular players governing synaptic vesicle fusion at highly specialized release sites in the active zone (AZ). However, the spatiotemporal organization of release at active synapses remains elusive, in part owing to the extremely small size of the AZ and the limited resolution of conventional approaches. Recent advances in fluorescence nanoscopy have revolutionized direct investigation of presynaptic release organization and dynamics. We discuss here recent nanoscopy-based studies of the molecular architecture, the spatial organization and dynamic regulation of release sites, and the mechanisms of release site replenishment. These findings have uncovered previously unknown levels of structural and functional organization at central synapses, with important implications for synaptic transmission and plasticity.
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Affiliation(s)
- Michael W Gramlich
- Department of Cell Biology and Physiology, Department of Biomedical Engineering, Washington University School of Medicine, St. Louis, MO, USA; Present address: Department of Physics, Auburn University, Auburn, AL, USA
| | - Vitaly A Klyachko
- Department of Cell Biology and Physiology, Department of Biomedical Engineering, Washington University School of Medicine, St. Louis, MO, USA.
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6
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Zhang XM, François U, Silm K, Angelo MF, Fernandez-Busch MV, Maged M, Martin C, Bernard V, Cordelières FP, Deshors M, Pons S, Maskos U, Bemelmans AP, Wojcik SM, El Mestikawy S, Humeau Y, Herzog E. A proline-rich motif on VGLUT1 reduces synaptic vesicle super-pool and spontaneous release frequency. eLife 2019; 8:50401. [PMID: 31663854 PMCID: PMC6861006 DOI: 10.7554/elife.50401] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2019] [Accepted: 10/27/2019] [Indexed: 12/29/2022] Open
Abstract
Glutamate secretion at excitatory synapses is tightly regulated to allow for the precise tuning of synaptic strength. Vesicular Glutamate Transporters (VGLUT) accumulate glutamate into synaptic vesicles (SV) and thereby regulate quantal size. Further, the number of release sites and the release probability of SVs maybe regulated by the organization of active-zone proteins and SV clusters. In the present work, we uncover a mechanism mediating an increased SV clustering through the interaction of VGLUT1 second proline-rich domain, endophilinA1 and intersectin1. This strengthening of SV clusters results in a combined reduction of axonal SV super-pool size and miniature excitatory events frequency. Our findings support a model in which clustered vesicles are held together through multiple weak interactions between Src homology three and proline-rich domains of synaptic proteins. In mammals, VGLUT1 gained a proline-rich sequence that recruits endophilinA1 and turns the transporter into a regulator of SV organization and spontaneous release.
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Affiliation(s)
- Xiao Min Zhang
- Interdisciplinary Institute for Neuroscience, Université de Bordeaux, Bordeaux, France.,Interdisciplinary Institute for Neuroscience CNRS UMR 5297, Bordeaux, France.,Department of Molecular Neurobiology, Max Planck Institute of Experimental Medicine, Göttingen, Germany
| | - Urielle François
- Interdisciplinary Institute for Neuroscience, Université de Bordeaux, Bordeaux, France.,Interdisciplinary Institute for Neuroscience CNRS UMR 5297, Bordeaux, France
| | - Kätlin Silm
- Neuroscience Paris Seine NPS, Université Pierre et Marie Curie INSERM U1130 CNRS UMR8246, Paris, France
| | - Maria Florencia Angelo
- Interdisciplinary Institute for Neuroscience, Université de Bordeaux, Bordeaux, France.,Interdisciplinary Institute for Neuroscience CNRS UMR 5297, Bordeaux, France
| | - Maria Victoria Fernandez-Busch
- Interdisciplinary Institute for Neuroscience, Université de Bordeaux, Bordeaux, France.,Interdisciplinary Institute for Neuroscience CNRS UMR 5297, Bordeaux, France
| | - Mona Maged
- Interdisciplinary Institute for Neuroscience, Université de Bordeaux, Bordeaux, France.,Interdisciplinary Institute for Neuroscience CNRS UMR 5297, Bordeaux, France
| | - Christelle Martin
- Interdisciplinary Institute for Neuroscience, Université de Bordeaux, Bordeaux, France.,Interdisciplinary Institute for Neuroscience CNRS UMR 5297, Bordeaux, France
| | - Véronique Bernard
- Neuroscience Paris Seine NPS, Université Pierre et Marie Curie INSERM U1130 CNRS UMR8246, Paris, France
| | - Fabrice P Cordelières
- Bordeaux Imaging Center, Université de Bordeaux, CNRS UMS 3420, INSERM US4, Bordeaux, France
| | - Melissa Deshors
- Interdisciplinary Institute for Neuroscience, Université de Bordeaux, Bordeaux, France.,Interdisciplinary Institute for Neuroscience CNRS UMR 5297, Bordeaux, France
| | - Stéphanie Pons
- Institut Pasteur, CNRS UMR 3571, Unité NISC, Paris, France
| | - Uwe Maskos
- Institut Pasteur, CNRS UMR 3571, Unité NISC, Paris, France
| | - Alexis Pierre Bemelmans
- Commissariat à l'Energie Atomique et aux Energies Alternatives (CEA), Direction de laRecherche Fondamentale (DRF), Institut de Biologie François Jacob (IBFJ), MolecularImaging Research Center (MIRCen), Fontenay-aux-Roses, France
| | - Sonja M Wojcik
- Department of Molecular Neurobiology, Max Planck Institute of Experimental Medicine, Göttingen, Germany
| | - Salah El Mestikawy
- Neuroscience Paris Seine NPS, Université Pierre et Marie Curie INSERM U1130 CNRS UMR8246, Paris, France.,Department of Psychiatry, Douglas Mental Health University Institute, McGill University, Montreal, Canada
| | - Yann Humeau
- Interdisciplinary Institute for Neuroscience, Université de Bordeaux, Bordeaux, France.,Interdisciplinary Institute for Neuroscience CNRS UMR 5297, Bordeaux, France
| | - Etienne Herzog
- Interdisciplinary Institute for Neuroscience, Université de Bordeaux, Bordeaux, France.,Interdisciplinary Institute for Neuroscience CNRS UMR 5297, Bordeaux, France
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7
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Henkel AW, Mouihate A, Welzel O. Differential Release of Exocytosis Marker Dyes Indicates Stimulation-Dependent Regulation of Synaptic Activity. Front Neurosci 2019; 13:1047. [PMID: 31632237 PMCID: PMC6783566 DOI: 10.3389/fnins.2019.01047] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2019] [Accepted: 09/18/2019] [Indexed: 02/05/2023] Open
Abstract
There is a general consensus that synaptic vesicular release by a full collapse process is the primary machinery of synaptic transmission. However, competing view suggests that synaptic vesicular release operates via a kiss-and-run mechanism. By monitoring the release dynamics of a synaptic vesicular marker, FM1-43 from individual synapses in hippocampal neurons, we found evidence that the release of synaptic vesicle was delayed by several seconds after the start of field stimulation. This phenomenon was associated with modified opening kinetics of fusion pores. Detailed analysis revealed that some synapses were completely inactive for a few seconds after stimulation, despite immediate calcium influx. This delay in vesicular release was modulated by various stimulation protocols and different frequencies, indicating an activity-dependent regulation mechanism for neurotransmitter exocytosis. Staurosporine, a drug known to induce “kiss-and-run” exocytosis, increased the proportion of delayed synapses as well as the delay duration, while fluoxetine acted contrarily. Besides being a serotonin reuptake inhibitor, it directly enhanced vesicle mobilization and reduced synaptic fatigue. Exocytosis was never delayed, when it was monitored with pH-sensitive probes, synaptopHlourin and αSyt-CypHerE5 antibody, indicating an instantaneous formation of a fusion pore that allowed rapid equilibration of vesicular lumenal pH but prevented FM1-43 release because of its slow dissociation from the inner vesicular membrane. Our observations suggest that synapses operate via a sequential “kiss-and-run” and “full-collapse” exocytosis mechanism. The initially narrow vesicular pore allows the equilibration of intravesicular pH which then progresses toward full fusion, causing FM1-43 release.
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Affiliation(s)
- Andreas W Henkel
- Department of Physiology, Faculty of Medicine, Kuwait University, Kuwait City, Kuwait
| | - Abdeslam Mouihate
- Department of Physiology, Faculty of Medicine, Kuwait University, Kuwait City, Kuwait
| | - Oliver Welzel
- Department of Psychiatry and Psychotherapy, University Hospital Erlangen, Erlangen, Germany
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8
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Richter KN, Patzelt C, Phan NTN, Rizzoli SO. Antibody-driven capture of synaptic vesicle proteins on the plasma membrane enables the analysis of their interactions with other synaptic proteins. Sci Rep 2019; 9:9231. [PMID: 31239503 PMCID: PMC6592915 DOI: 10.1038/s41598-019-45729-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2019] [Accepted: 06/13/2019] [Indexed: 01/07/2023] Open
Abstract
Many organelles from the secretory pathway fuse to the plasma membrane, to exocytose different cargoes. Their proteins are then retrieved from the plasma membrane by endocytosis, and the organelles are re-formed. It is generally unclear whether the organelle proteins colocalize when they are on the plasma membrane, or whether they disperse. To address this, we generated here a new approach, which we tested on synaptic vesicles, organelles that are known to exo- and endocytose frequently. We tagged the synaptotagmin molecules of newly exocytosed vesicles using clusters of primary and secondary antibodies targeted against the luminal domains of these molecules. The antibody clusters are too large for endocytosis, and thus sequestered the synaptotagmin molecules on the plasma membrane. Immunostainings for other synaptic molecules then revealed whether they colocalized with the sequestered synaptotagmin molecules. We suggest that such assays may be in the future extended to other cell types and other organelles.
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Affiliation(s)
- Katharina N Richter
- Institute for Neuro- and Sensory Physiology, Center for Biostructural Imaging of Neurodegeneration, University Medical Center Göttingen, Göttingen, Germany.
| | - Christina Patzelt
- Institute for Neuro- and Sensory Physiology, Center for Biostructural Imaging of Neurodegeneration, University Medical Center Göttingen, Göttingen, Germany
| | - Nhu T N Phan
- Institute for Neuro- and Sensory Physiology, Center for Biostructural Imaging of Neurodegeneration, University Medical Center Göttingen, Göttingen, Germany
| | - Silvio O Rizzoli
- Institute for Neuro- and Sensory Physiology, Center for Biostructural Imaging of Neurodegeneration, University Medical Center Göttingen, Göttingen, Germany.
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9
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Rudling JE, Drever BD, Reid B, Bewick GS. Importance of Full-Collapse Vesicle Exocytosis for Synaptic Fatigue-Resistance at Rat Fast and Slow Muscle Neuromuscular Junctions. Int J Mol Sci 2018; 19:ijms19071936. [PMID: 30004407 PMCID: PMC6073735 DOI: 10.3390/ijms19071936] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2018] [Revised: 06/12/2018] [Accepted: 06/24/2018] [Indexed: 11/16/2022] Open
Abstract
Neurotransmitter release during trains of activity usually involves two vesicle pools (readily releasable pool, or RRP, and reserve pool, or RP) and two exocytosis mechanisms (“full-collapse” and “kiss-and-run”). However, synaptic terminals are adapted to differing patterns of use and the relationship of these factors to enabling terminals to adapt to differing transmitter release demands is not clear. We have therefore tested their contribution to a terminal’s ability to maintain release, or synaptic fatiguability in motor terminals innervating fast-twitch (fatiguable), and postural slow-twitch (fatigue-resistant) muscles. We used electrophysiological recording of neurotransmission and fluorescent dye markers of vesicle recycling to compare the effects of kinase inhibitors of varying myosin light chain kinase (MLCK) selectivity (staurosporine, wortmannin, LY294002 & ML-9) on vesicle pools, exocytosis mechanisms, and sustained neurotransmitter release, using postural-type activity train (20 Hz for 10 min) in these muscles. In both muscles, a small, rapidly depleted vesicle pool (the RRP) was inhibitor insensitive, continuing to release FM1-43, which is a marker of full-collapse exocytosis. MLCK-inhibiting kinases blocked all remaining FM1-43 loss from labelled vesicles. However, FM2-10 release only slowed, indicating continuing kiss-and-run exocytosis. Despite this, kinase inhibitors did not affect transmitter release fatiguability under normal conditions. However, augmenting release in high Ca2+ entirely blocked the synaptic fatigue-resistance of terminals in slow-twitch muscles. Thus, full-collapse exocytosis from most vesicles (the RP) is not essential for maintaining release during a single prolonged train. However, it becomes critical in fatigue-resistant terminals during high vesicle demand.
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Affiliation(s)
- Jane E Rudling
- Institute of Medical Sciences, School of Medicine, Medical Sciences & Nutrition, University of Aberdeen, Aberdeen AB25 2ZD, UK.
| | - Benjamin D Drever
- Institute of Medical Sciences, School of Medicine, Medical Sciences & Nutrition, University of Aberdeen, Aberdeen AB25 2ZD, UK.
| | - Brian Reid
- Institute of Medical Sciences, School of Medicine, Medical Sciences & Nutrition, University of Aberdeen, Aberdeen AB25 2ZD, UK.
| | - Guy S Bewick
- Institute of Medical Sciences, School of Medicine, Medical Sciences & Nutrition, University of Aberdeen, Aberdeen AB25 2ZD, UK.
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10
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Milovanovic D, De Camilli P. Synaptic Vesicle Clusters at Synapses: A Distinct Liquid Phase? Neuron 2017; 93:995-1002. [PMID: 28279363 DOI: 10.1016/j.neuron.2017.02.013] [Citation(s) in RCA: 70] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2016] [Revised: 02/06/2017] [Accepted: 02/06/2017] [Indexed: 11/17/2022]
Abstract
Phase separation in the cytoplasm is emerging as a major principle in intracellular organization. In this process, sets of macromolecules assemble themselves into liquid compartments that are distinct from the surrounding medium but are not delimited by membrane boundaries. Here, we discuss how phase separation, in which a component of one of the two phases is vesicles rather than macromolecules, could underlie the formation of synaptic vesicle (SV) clusters in proximity to presynaptic sites. The organization of SVs into a liquid phase could explain how SVs remain tightly clustered without being stably bound to a scaffold so that they can be efficiently recruited to release site by active zone components.
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Affiliation(s)
- Dragomir Milovanovic
- Departments of Neuroscience and Cell Biology, Program in Cellular Neuroscience, Neurodegeneration and Repair, Kavli Institute for Neuroscience, Howard Hughes Medical Institute, Yale University School of Medicine, New Haven, CT 06520, USA
| | - Pietro De Camilli
- Departments of Neuroscience and Cell Biology, Program in Cellular Neuroscience, Neurodegeneration and Repair, Kavli Institute for Neuroscience, Howard Hughes Medical Institute, Yale University School of Medicine, New Haven, CT 06520, USA.
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11
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Joensuu M, Padmanabhan P, Durisic N, Bademosi ATD, Cooper-Williams E, Morrow IC, Harper CB, Jung W, Parton RG, Goodhill GJ, Papadopulos A, Meunier FA. Subdiffractional tracking of internalized molecules reveals heterogeneous motion states of synaptic vesicles. J Cell Biol 2016; 215:277-292. [PMID: 27810917 PMCID: PMC5080683 DOI: 10.1083/jcb.201604001] [Citation(s) in RCA: 49] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2016] [Accepted: 09/30/2016] [Indexed: 11/23/2022] Open
Abstract
Joensuu et al. describe a tool for subdiffractional tracking of internalized molecules. They reveal that synaptic vesicles exhibit stochastic switching between heterogeneous diffusive and transport states in live hippocampal nerve terminals. Our understanding of endocytic pathway dynamics is severely restricted by the diffraction limit of light microscopy. To address this, we implemented a novel technique based on the subdiffractional tracking of internalized molecules (sdTIM). This allowed us to image anti–green fluorescent protein Atto647N-tagged nanobodies trapped in synaptic vesicles (SVs) from live hippocampal nerve terminals expressing vesicle-associated membrane protein 2 (VAMP2)–pHluorin with 36-nm localization precision. Our results showed that, once internalized, VAMP2–pHluorin/Atto647N–tagged nanobodies exhibited a markedly lower mobility than on the plasma membrane, an effect that was reversed upon restimulation in presynapses but not in neighboring axons. Using Bayesian model selection applied to hidden Markov modeling, we found that SVs oscillated between diffusive states or a combination of diffusive and transport states with opposite directionality. Importantly, SVs exhibiting diffusive motion were relatively less likely to switch to the transport motion. These results highlight the potential of the sdTIM technique to provide new insights into the dynamics of endocytic pathways in a wide variety of cellular settings.
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Affiliation(s)
- Merja Joensuu
- Clem Jones Centre for Ageing Dementia Research, The University of Queensland, Brisbane, Queensland 4072, Australia.,Queensland Brain Institute, The University of Queensland, Brisbane, Queensland 4072, Australia
| | - Pranesh Padmanabhan
- Queensland Brain Institute, The University of Queensland, Brisbane, Queensland 4072, Australia
| | - Nela Durisic
- Queensland Brain Institute, The University of Queensland, Brisbane, Queensland 4072, Australia
| | - Adekunle T D Bademosi
- Clem Jones Centre for Ageing Dementia Research, The University of Queensland, Brisbane, Queensland 4072, Australia.,Queensland Brain Institute, The University of Queensland, Brisbane, Queensland 4072, Australia
| | | | - Isabel C Morrow
- Clem Jones Centre for Ageing Dementia Research, The University of Queensland, Brisbane, Queensland 4072, Australia.,Queensland Brain Institute, The University of Queensland, Brisbane, Queensland 4072, Australia
| | - Callista B Harper
- Clem Jones Centre for Ageing Dementia Research, The University of Queensland, Brisbane, Queensland 4072, Australia.,Queensland Brain Institute, The University of Queensland, Brisbane, Queensland 4072, Australia
| | - WooRam Jung
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland 4072, Australia.,Centre for Microscopy and Microanalysis, The University of Queensland, Brisbane, Queensland 4072, Australia
| | - Robert G Parton
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland 4072, Australia.,Centre for Microscopy and Microanalysis, The University of Queensland, Brisbane, Queensland 4072, Australia
| | - Geoffrey J Goodhill
- Queensland Brain Institute, The University of Queensland, Brisbane, Queensland 4072, Australia.,School of Mathematics and Physics, The University of Queensland, Brisbane, Queensland 4072, Australia
| | - Andreas Papadopulos
- Clem Jones Centre for Ageing Dementia Research, The University of Queensland, Brisbane, Queensland 4072, Australia .,Queensland Brain Institute, The University of Queensland, Brisbane, Queensland 4072, Australia
| | - Frédéric A Meunier
- Clem Jones Centre for Ageing Dementia Research, The University of Queensland, Brisbane, Queensland 4072, Australia .,Queensland Brain Institute, The University of Queensland, Brisbane, Queensland 4072, Australia
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12
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Jang S, Nelson JC, Bend EG, Rodríguez-Laureano L, Tueros FG, Cartagenova L, Underwood K, Jorgensen EM, Colón-Ramos DA. Glycolytic Enzymes Localize to Synapses under Energy Stress to Support Synaptic Function. Neuron 2016; 90:278-91. [PMID: 27068791 DOI: 10.1016/j.neuron.2016.03.011] [Citation(s) in RCA: 181] [Impact Index Per Article: 22.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2015] [Revised: 01/12/2016] [Accepted: 03/08/2016] [Indexed: 01/07/2023]
Abstract
Changes in neuronal activity create local and transient changes in energy demands at synapses. Here we discover a metabolic compartment that forms in vivo near synapses to meet local energy demands and support synaptic function in Caenorhabditis elegans neurons. Under conditions of energy stress, glycolytic enzymes redistribute from a diffuse localization in the cytoplasm to a punctate localization adjacent to synapses. Glycolytic enzymes colocalize, suggesting the ad hoc formation of a glycolysis compartment, or a "glycolytic metabolon," that can maintain local levels of ATP. Local formation of the glycolytic metabolon is dependent on presynaptic scaffolding proteins, and disruption of the glycolytic metabolon blocks the synaptic vesicle cycle, impairs synaptic recovery, and affects locomotion. Our studies indicate that under energy stress conditions, energy demands in C. elegans synapses are met locally through the assembly of a glycolytic metabolon to sustain synaptic function and behavior. VIDEO ABSTRACT.
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Affiliation(s)
- SoRi Jang
- Program in Cellular Neuroscience, Neurodegeneration, and Repair, Department of Cell Biology and Department of Neuroscience, Yale University School of Medicine, P.O. Box 9812, New Haven, CT 06536-0812, USA
| | - Jessica C Nelson
- Program in Cellular Neuroscience, Neurodegeneration, and Repair, Department of Cell Biology and Department of Neuroscience, Yale University School of Medicine, P.O. Box 9812, New Haven, CT 06536-0812, USA
| | - Eric G Bend
- Department of Biology, Howard Hughes Medical Institute, University of Utah, Salt Lake City, UT 84112-0840, USA
| | - Lucelenie Rodríguez-Laureano
- Program in Cellular Neuroscience, Neurodegeneration, and Repair, Department of Cell Biology and Department of Neuroscience, Yale University School of Medicine, P.O. Box 9812, New Haven, CT 06536-0812, USA
| | - Felipe G Tueros
- Laboratorio de Microbiología, Facultad de Ciencias Biológicas, Universidad Ricardo Palma, P.O. Box 1801, Lima 33, Perú
| | - Luis Cartagenova
- Program in Cellular Neuroscience, Neurodegeneration, and Repair, Department of Cell Biology and Department of Neuroscience, Yale University School of Medicine, P.O. Box 9812, New Haven, CT 06536-0812, USA
| | - Katherine Underwood
- Program in Cellular Neuroscience, Neurodegeneration, and Repair, Department of Cell Biology and Department of Neuroscience, Yale University School of Medicine, P.O. Box 9812, New Haven, CT 06536-0812, USA
| | - Erik M Jorgensen
- Department of Biology, Howard Hughes Medical Institute, University of Utah, Salt Lake City, UT 84112-0840, USA
| | - Daniel A Colón-Ramos
- Program in Cellular Neuroscience, Neurodegeneration, and Repair, Department of Cell Biology and Department of Neuroscience, Yale University School of Medicine, P.O. Box 9812, New Haven, CT 06536-0812, USA; Instituto de Neurobiología, Recinto de Ciencias Médicas, Universidad de Puerto Rico, 201 Boulevard del Valle, San Juan 00901, Puerto Rico.
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13
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A nanoscale resolution view on synaptic vesicle dynamics. Synapse 2014; 69:256-67. [DOI: 10.1002/syn.21795] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2014] [Revised: 11/20/2014] [Accepted: 11/27/2014] [Indexed: 12/31/2022]
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14
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Kisiel M, McKenzie K, Stewart B. Localization and mobility of synaptic vesicles in Myosin VI mutants of Drosophila. PLoS One 2014; 9:e102988. [PMID: 25062032 PMCID: PMC4111356 DOI: 10.1371/journal.pone.0102988] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2013] [Accepted: 06/26/2014] [Indexed: 11/25/2022] Open
Abstract
Background At the Drosophila neuromuscular junction (NMJ), synaptic vesicles are mobile; however, the mechanisms that regulate vesicle traffic at the nerve terminal are not fully understood. Myosin VI has been shown to be important for proper synaptic physiology and morphology at the NMJ, likely by functioning as a vesicle tether. Here we investigate vesicle dynamics in Myosin VI mutants of Drosophila. Results In Drosophila, Myosin VI is encoded by the gene, jaguar (jar). To visualize active vesicle cycling we used FM dye loading and compared loss of function alleles of jar with controls. These studies revealed a differential distribution of vesicles at the jar mutant nerve terminal, with the newly endocytosed vesicles observed throughout the mutant boutons in contrast to the peripheral localization visualized at control NMJs. This finding is consistent with a role for Myosin VI in restraining vesicle mobility at the synapse to ensure proper localization. To further investigate regulation of vesicle dynamics by Myosin VI, FRAP analysis was used to analyze movement of GFP-labeled synaptic vesicles within individual boutons. FRAP revealed that synaptic vesicles are moving more freely in the jar mutant boutons, indicated by changes in initial bleach depth and rapid recovery of fluorescence following photobleaching. Conclusion This data provides insights into the role for Myosin VI in mediating synaptic vesicle dynamics at the nerve terminal. We observed mislocalization of actively cycling vesicles and an apparent increase in vesicle mobility when Myosin VI levels are reduced. These observations support the notion that a major function of Myosin VI in the nerve terminal is tethering synaptic vesicles to proper sub-cellular location within the bouton.
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Affiliation(s)
- Marta Kisiel
- Department of Biology, University of Toronto Mississauga, Mississauga, Canada
| | - Kristopher McKenzie
- Department of Biology, University of Toronto Mississauga, Mississauga, Canada
| | - Bryan Stewart
- Department of Biology, University of Toronto Mississauga, Mississauga, Canada
- Department of Cell and Systems Biology, University of Toronto, Toronto, Canada
- * E-mail:
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15
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Bui L, Glavinović MI. Is replenishment of the readily releasable pool associated with vesicular movement? Cogn Neurodyn 2013; 8:99-110. [PMID: 24624230 DOI: 10.1007/s11571-013-9264-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2013] [Revised: 06/19/2013] [Accepted: 07/23/2013] [Indexed: 12/30/2022] Open
Abstract
At the excitatory synapse of rat hippocampus the short-term synaptic depression observed during long high-frequency stimulation is associated with slower replenishment of the readily-releasable pool. Given that the replenishment rate is also not [Ca(++)]o sensitive this puts into question a widely held notion that the vesicles-constrained by the cytoskeleton and rendered free from such constraints by Ca(++) entry that renders them more mobile-are important in the replenishment of the readily-releasable pool. This raises a question-Is vesicular replenishment of the readily releasable pool associated with significant movement? To answer this question we evaluated how okadaic acid and staurosporine (compounds known to affect vesicular mobility) influence the replenishment rate. We used patterned stimulation on the Schaffer collateral fiber pathway and recorded the excitatory post-synaptic currents (EPSCs) from rat CA1 neurons, in the absence and presence of these drugs. The parameters of a circuit model with two vesicular pools were estimated by minimizing the squared difference between the ESPC amplitudes and simulated model output. [Ca(2+)]o did not influence the progressive decrease of the replenishment rate during long, high frequency stimulation. Okadaic acid did not significantly affect any parameters of the vesicular storage and release system, including the replenishment rate. Staurosporine reduced the replenishment coupling, but not the replenishment rate, and this is owing to the fact that it also reduces the ability of the readily releasable pool to contain quanta. Moreover, these compounds were ineffective in influencing how the replenishment rate decreases during long, high frequency stimulation. In conclusion at the excitatory synapses of rat hippocampus the replenishment of the readily releasable pool does not appear to be associated with a significant vesicular movement, and during long high frequency stimulation [Ca(++)]o does not influence the progressive decrease of vesicular replenishment.
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Affiliation(s)
- Loc Bui
- Department of Physiology, McGill University, 3655 Sir William Osler Promenade, Montreal, H3G 1Y6 Canada
| | - Mladen I Glavinović
- Department of Physiology, McGill University, 3655 Sir William Osler Promenade, Montreal, H3G 1Y6 Canada
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16
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Hoopmann P, Rizzoli SO, Betz WJ. Imaging synaptic vesicle recycling by staining and destaining vesicles with FM dyes. Cold Spring Harb Protoc 2012; 2012:77-83. [PMID: 22194270 DOI: 10.1101/pdb.prot067603] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
The synaptic vesicle is the essential organelle of the synapse. Many approaches for studying synaptic vesicle recycling have been devised, one of which, the styryl (FM) dye, is well suited for this purpose. FM dyes reversibly stain, but do not permeate, membranes; hence they can specifically label membrane-bound organelles. Their quantum yield is drastically higher when bound to membranes than when in aqueous solution. This protocol describes the imaging of synaptic vesicle recycling by staining and destaining vesicles with FM dyes. Nerve terminals are stimulated (electrically or by depolarization with high K(+)) in the presence of dye, their vesicles are then allowed to recycle, and finally dye is washed from the chamber. In neuromuscular junction (NMJ) preparations, movements of the muscle must be inhibited if imaging during stimulation is desired (e.g., by application of curare, a potent acetylcholine receptor inhibitor). The main characteristics of FM dyes are also reviewed here, as are recent FM dye monitoring techniques that have been used to investigate the kinetics of synaptic vesicle fusion.
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17
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Opazo F, Rizzoli SO. The fate of synaptic vesicle components upon fusion. Commun Integr Biol 2011; 3:427-9. [PMID: 21057631 DOI: 10.4161/cib.3.5.12132] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2010] [Accepted: 04/20/2010] [Indexed: 11/19/2022] Open
Abstract
Neurotransmitter release relies on the fusion of synaptic vesicles with the plasma membrane of synaptic boutons, which is followed by the recycling of vesicle components and formation of new vesicles. It is not yet clear whether upon fusion the vesicles persist as multimolecular patches in the plasma membrane, or whether they segregate into individual components. Evidence supporting each of these two models has been suggested in recent years. Using diffraction-unlimited imaging (stimulated emission depletion, or STED) of native synaptic vesicle proteins, we have proposed that vesicle proteins remain in clusters on the neuronal surface. These clusters do not appear to intermix. We discuss here these findings in the context of previous studies on synaptic vesicle fusion, and we propose a recycling model which accounts for most of the recent findings on the post-fusion fate of synaptic vesicle components.
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Affiliation(s)
- Felipe Opazo
- European Neuroscience Institute Göttingen; DFG Center for Molecular Physiology of the Brain (CMPB); Göttingen, Germany
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18
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Seabrooke S, Stewart BA. Synaptic transmission and plasticity are modulated by nonmuscle myosin II at the neuromuscular junction of Drosophila. J Neurophysiol 2011; 105:1966-76. [PMID: 21325687 DOI: 10.1152/jn.00718.2010] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The synaptic vesicle population in a nerve terminal is traditionally divided into subpopulations according to physiological criteria; the readily releasable pool (RRP), the recycling pool, and the reserve pool. It is recognized that the RRP subserves synaptic transmission evoked by low-frequency neural activity and that the recycling and reserve populations are called on to supply vesicles as neural activity increases. Here we investigated the contribution of nonmuscle myosin II (NMMII) to synaptic transmission with emphasis on the role a motor protein could play in the supply of vesicles. We used Drosophila genetics to manipulate NMMII and assessed synaptic transmission at the larval neuromuscular junction. We observed a positive correlation between synaptic strength at low-frequency stimulation and NMMII expression: reducing NMMII reduced the evoked response, while increasing NMMII increased the evoked response. Further, we found that NMMII contributed to the spontaneous release of vesicles differentially from evoked release, suggesting differential contribution to these two release mechanisms. By measuring synaptic responses under conditions of differing external calcium concentration in saline, we found that NMMII is important for normal synaptic transmission under high-frequency stimulation. This research identifies diverse functions for NMMII in synaptic transmission and suggests that this motor protein is an active contributor to the physiology of synaptic vesicle recruitment.
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Affiliation(s)
- Sara Seabrooke
- Department of Biology, University of Toronto, Mississauga, Ontario, Canada
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19
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Siksou L, Triller A, Marty S. Ultrastructural organization of presynaptic terminals. Curr Opin Neurobiol 2011; 21:261-8. [PMID: 21247753 DOI: 10.1016/j.conb.2010.12.003] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2010] [Accepted: 12/17/2010] [Indexed: 01/03/2023]
Abstract
In response to calcium influx, synaptic vesicles fuse very rapidly with the plasma membrane to release their neurotransmitter content. An important mechanism for sustained release includes the formation of new vesicles by local endocytosis. How synaptic vesicles are trafficked from the sites of endocytosis to the sites of release and how they are maintained at the release sites remain poorly understood. Recent studies using fast freezing immobilization and electron tomography have led to insights on the ultrastructural organization of presynaptic boutons and how these structural elements may maintain synaptic vesicles and organize their exocytosis at particular areas of the plasma membrane.
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Affiliation(s)
- Léa Siksou
- Institute of Biology of the Ecole Normale Supérieure, 46 rue d'Ulm, 75005 Paris, France
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20
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High- and low-mobility stages in the synaptic vesicle cycle. Biophys J 2010; 99:675-84. [PMID: 20643088 DOI: 10.1016/j.bpj.2010.04.054] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2009] [Revised: 04/12/2010] [Accepted: 04/20/2010] [Indexed: 11/24/2022] Open
Abstract
Synaptic vesicles need to be mobile to reach their release sites during synaptic activity. We investigated vesicle mobility throughout the synaptic vesicle cycle using both conventional and subdiffraction-resolution stimulated emission depletion fluorescence microscopy. Vesicle tracking revealed that recently endocytosed synaptic vesicles are highly mobile for a substantial time period after endocytosis. They later undergo a maturation process and integrate into vesicle clusters where they exhibit little mobility. Despite the differences in mobility, both recently endocytosed and mature vesicles are exchanged between synapses. Electrical stimulation does not seem to affect the mobility of the two types of vesicles. After exocytosis, the vesicle material is mobile in the plasma membrane, although the movement appears to be somewhat limited. Increasing the proportion of fused vesicles (by stimulating exocytosis while simultaneously blocking endocytosis) leads to substantially higher mobility. We conclude that both high- and low-mobility states are characteristic of synaptic vesicle movement.
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21
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Seabrooke S, Qiu X, Stewart BA. Nonmuscle Myosin II helps regulate synaptic vesicle mobility at the Drosophila neuromuscular junction. BMC Neurosci 2010; 11:37. [PMID: 20233422 PMCID: PMC2853426 DOI: 10.1186/1471-2202-11-37] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2009] [Accepted: 03/16/2010] [Indexed: 11/22/2022] Open
Abstract
Background Although the mechanistic details of the vesicle transport process from the cell body to the nerve terminal are well described, the mechanisms underlying vesicle traffic within nerve terminal boutons is relatively unknown. The actin cytoskeleton has been implicated but exactly how actin or actin-binding proteins participate in vesicle movement is not clear. Results In the present study we have identified Nonmuscle Myosin II as a candidate molecule important for synaptic vesicle traffic within Drosophila larval neuromuscular boutons. Nonmuscle Myosin II was found to be localized at the Drosophila larval neuromuscular junction; genetics and pharmacology combined with the time-lapse imaging technique FRAP were used to reveal a contribution of Nonmuscle Myosin II to synaptic vesicle movement. FRAP analysis showed that vesicle dynamics were highly dependent on the expression level of Nonmuscle Myosin II. Conclusion Our results provide evidence that Nonmuscle Myosin II is present presynaptically, is important for synaptic vesicle mobility and suggests a role for Nonmuscle Myosin II in shuttling vesicles at the Drosophila neuromuscular junction. This work begins to reveal the process by which synaptic vesicles traverse within the bouton.
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Affiliation(s)
- Sara Seabrooke
- Department of Biology, University of Toronto, Mississauga, ON L5L 1C6, Canada
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22
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Opazo F, Punge A, Bückers J, Hoopmann P, Kastrup L, Hell SW, Rizzoli SO. Limited Intermixing of Synaptic Vesicle Components upon Vesicle Recycling. Traffic 2010; 11:800-12. [DOI: 10.1111/j.1600-0854.2010.01058.x] [Citation(s) in RCA: 90] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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23
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Fernández-Busnadiego R, Zuber B, Maurer UE, Cyrklaff M, Baumeister W, Lucic V. Quantitative analysis of the native presynaptic cytomatrix by cryoelectron tomography. ACTA ACUST UNITED AC 2010; 188:145-56. [PMID: 20065095 PMCID: PMC2812849 DOI: 10.1083/jcb.200908082] [Citation(s) in RCA: 181] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The filamentous structures that tether exocytic vesicles to the plasma membrane in the active zone are rearranged in response to synaptic stimulation. The presynaptic terminal contains a complex network of filaments whose precise organization and functions are not yet understood. The cryoelectron tomography experiments reported in this study indicate that these structures play a prominent role in synaptic vesicle release. Docked synaptic vesicles did not make membrane to membrane contact with the active zone but were instead linked to it by tethers of different length. Our observations are consistent with an exocytosis model in which vesicles are first anchored by long (>5 nm) tethers that give way to multiple short tethers once vesicles enter the readily releasable pool. The formation of short tethers was inhibited by tetanus toxin, indicating that it depends on soluble N-ethyl-maleimide sensitive fusion protein attachment protein receptor complex assembly. Vesicles were extensively interlinked via a set of connectors that underwent profound rearrangements upon synaptic stimulation and okadaic acid treatment, suggesting a role of these connectors in synaptic vesicle mobilization and neurotransmitter release.
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Affiliation(s)
- Rubén Fernández-Busnadiego
- Department of Molecular Structural Biology, Max Planck Institute of Biochemistry, D-82152 Martinsried, Germany
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24
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Abstract
Synaptic ribbons are organelles that tether vesicles at the presynaptic active zones of sensory neurons in the visual, auditory, and vestibular systems. These neurons generate sustained, graded electrical signals in response to sensory stimuli, and fidelity of transmission therefore requires their synapses to release neurotransmitter continuously at high rates. It has long been thought that the ribbons at the active zones of sensory synapses accomplish this task by enhancing the size and accessibility of the readily releasable pool of synaptic vesicles, which may represent the vesicles attached to the ribbon. Recent evidence suggests that synaptic ribbons immobilize vesicles in the resting cell and coordinate the transient, synchronous release of vesicles in response to stimulation, but it is not yet clear how the ribbon can efficiently mobilize and coordinate multiple vesicles for release. However, detailed anatomical, electrophysiological, and optical studies have begun to reveal the mechanics of release at ribbon synapses, and this multidisciplinary approach promises to reconcile structure, function, and mechanism at these important sensory synapses.
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Affiliation(s)
- Lisamarie LoGiudice
- Department of Neurobiology and Behavior, State University of New York, Stony Brook, New York 11794-5230, USA
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25
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The synaptic vesicle cluster: A source of endocytic proteins during neurotransmitter release. Neuroscience 2009; 158:204-10. [DOI: 10.1016/j.neuroscience.2008.03.035] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2007] [Revised: 03/17/2008] [Accepted: 03/18/2008] [Indexed: 12/11/2022]
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26
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Westphal V, Rizzoli SO, Lauterbach MA, Kamin D, Jahn R, Hell SW. Video-Rate Far-Field Optical Nanoscopy Dissects Synaptic Vesicle Movement. Science 2008; 320:246-9. [DOI: 10.1126/science.1154228] [Citation(s) in RCA: 626] [Impact Index Per Article: 39.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
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27
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Bertuglia S, Ichimura H, Fossati G, Parthasarathi K, Leoni F, Modena D, Cremonesi P, Bhattacharya J, Mascagni P. ITF1697, a stable Lys-Pro-containing peptide, inhibits weibel-palade body exocytosis induced by ischemia/reperfusion and pressure elevation. Mol Med 2008; 13:615-24. [PMID: 17948065 DOI: 10.2119/2007-00079.bertuglia] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2007] [Accepted: 10/09/2007] [Indexed: 11/06/2022] Open
Abstract
A number of Lys-Pro-containing short peptides have been described as possessing a variety of biological activities in vitro. Because of limited metabolic stability, however, their efficacy in vivo is uncertain. To exploit the pharmacological potential of Lys-Pro-containing short peptides, we synthesized a series of chemically modified forms of these peptides. One of them, ITF1697 (Gly-(Nalpha-Et)Lys-Pro-Arg) was stable in vivo and particularly efficacious in experimental models of disseminated endotoxemia and of cardiovascular disorders. Using intravital fluorescence microscopy, we studied the peptide cellular and molecular basis of protection in the Syrian hamster cheek pouch microcirculation subjected to ischemia/reperfusion (I/R) and in pressure elevation-induced proinflammatory responses in isolated Sprague-Dawley rat lungs. Continuous intravenous infusion of ITF1697 at 0.1 to 100 mug/kg/min nearly completely protected the cheek pouch microcirculation from I/R injury as measured by decreased vascular permeability and increased capillary perfusion. Adhesion of leukocytes and platelets to blood vessels was strongly inhibited by the peptide. ITF1697 exerted its activity at the early stages of endothelial activation and inhibited P-selectin and von Willebrand factor secretion. Further mechanistic studies in the rat lung preparation revealed that the peptide inhibited the intracellular Ca(2+)-dependent fusion of Weibel-Palade bodies with the plasma membrane. The ability of ITF1697 to inhibit the early functions of activated endothelial cells, such as the exocytosis of Weibel-Palade bodies, represents a novel and promising pharmacological tool in model of pathologies of a variety of microvascular disorders.
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Affiliation(s)
- Silvia Bertuglia
- CNR Institute of Clinical Physiology, Medical School, University of Pisa, Pisa, Italy
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28
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Lochner JE, Honigman LS, Grant WF, Gessford SK, Hansen AB, Silverman MA, Scalettar BA. Activity-dependent release of tissue plasminogen activator from the dendritic spines of hippocampal neurons revealed by live-cell imaging. ACTA ACUST UNITED AC 2007; 66:564-77. [PMID: 16555239 DOI: 10.1002/neu.20250] [Citation(s) in RCA: 87] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Tissue plasminogen activator (tPA) has been implicated in a variety of important cellular functions, including learning-related synaptic plasticity and potentiating N-methyl-D-aspartate (NMDA) receptor-dependent signaling. These findings suggest that tPA may localize to, and undergo activity-dependent secretion from, synapses; however, conclusive data supporting these hypotheses have remained elusive. To elucidate these issues, we studied the distribution, dynamics, and depolarization-induced secretion of tPA in hippocampal neurons, using fluorescent chimeras of tPA. We found that tPA resides in dense-core granules (DCGs) that traffic to postsynaptic dendritic spines and that can remain in spines for extended periods. We also found that depolarization induced by high potassium levels elicits a slow, partial exocytotic release of tPA from DCGs in spines that is dependent on extracellular Ca(+2) concentrations. This slow, partial release demonstrates that exocytosis occurs via a mechanism, such as fuse-pinch-linger, that allows partial release and reuse of DCG cargo and suggests a mechanism that hippocampal neurons may rely upon to avoid depleting tPA at active synapses. Our results also demonstrate release of tPA at a site that facilitates interaction with NMDA-type glutamate receptors, and they provide direct confirmation of fundamental hypotheses about tPA localization and release that bear on its neuromodulatory functions, for example, in learning and memory.
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Affiliation(s)
- Janis E Lochner
- Department of Chemistry, Lewis & Clark College, Portland, OR 97219, USA.
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Staras K. Share and share alike: trading of presynaptic elements between central synapses. Trends Neurosci 2007; 30:292-8. [PMID: 17467066 DOI: 10.1016/j.tins.2007.04.005] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2007] [Revised: 03/20/2007] [Accepted: 04/18/2007] [Indexed: 11/21/2022]
Abstract
Central presynaptic terminals harbour synaptic vesicles (SVs) and synapse-specific proteins necessary for neurotransmission. Classically, these elements were thought to reside more or less stably at individual mature synapses, giving rise to the idea that each terminal was essentially an independent functional unit. However, emerging evidence from fluorescence imaging studies in hippocampal cultured neurons is now challenging this view, suggesting that neighbouring synapses along axons share vesicles, and also other synaptic elements, at high levels. This raises the possibility that control of import and export might be an important regulatory target for the maintenance of release sites, modulation of synaptic efficacy and formation of new synaptic contacts. Here, temporal synaptic stability and the functional consequences for presynaptic operation will be considered.
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Affiliation(s)
- Kevin Staras
- MRC Laboratory for Molecular Cell Biology and Cell Biology Unit, University College London, London, UK.
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30
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Tsuriel S, Geva R, Zamorano P, Dresbach T, Boeckers T, Gundelfinger ED, Garner CC, Ziv NE. Local sharing as a predominant determinant of synaptic matrix molecular dynamics. PLoS Biol 2007; 4:e271. [PMID: 16903782 PMCID: PMC1540708 DOI: 10.1371/journal.pbio.0040271] [Citation(s) in RCA: 137] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2005] [Accepted: 06/14/2006] [Indexed: 01/03/2023] Open
Abstract
Recent studies suggest that central nervous system synapses can persist for weeks, months, perhaps lifetimes, yet little is known as to how synapses maintain their structural and functional characteristics for so long. As a step toward a better understanding of synaptic maintenance we examined the loss, redistribution, reincorporation, and replenishment dynamics of Synapsin I and ProSAP2/Shank3, prominent presynaptic and postsynaptic matrix molecules, respectively. Fluorescence recovery after photobleaching and photoactivation experiments revealed that both molecules are continuously lost from, redistributed among, and reincorporated into synaptic structures at time-scales of minutes to hours. Exchange rates were not affected by inhibiting protein synthesis or proteasome-mediated protein degradation, were accelerated by stimulation, and greatly exceeded rates of replenishment from somatic sources. These findings indicate that the dynamics of key synaptic matrix molecules may be dominated by local protein exchange and redistribution, whereas protein synthesis and degradation serve to maintain and regulate the sizes of local, shared pools of these proteins. To understand processes involved in synaptic maintenance, the authors examine the loss, redistribution, reincorporation and replenishment dynamics of two key synaptic proteins, Synapsin I and ProSAP2/Shank3.
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Affiliation(s)
- Shlomo Tsuriel
- The Rappaport Family Institute for Research in the Medical Sciences, Technion Faculty of Medicine, Haifa, Israel
- The Department of Physiology, Technion Faculty of Medicine, Haifa, Israel
| | - Ran Geva
- The Rappaport Family Institute for Research in the Medical Sciences, Technion Faculty of Medicine, Haifa, Israel
- The Department of Physiology, Technion Faculty of Medicine, Haifa, Israel
| | - Pedro Zamorano
- Department of Psychiatry and Behavioral Science, Nancy Pritzker Laboratory, Stanford University, Palo Alto, California, United States of America
| | - Thomas Dresbach
- Institute of Anatomy and Cell Biology II, University of Heidelberg, Heidelberg, Germany
| | - Tobias Boeckers
- Institute of Anatomy and Cell Biology, University of Ulm, Ulm, Germany
| | - Eckart D Gundelfinger
- Department of Neurochemistry and Molecular Biology, Leibniz Institute for Neurobiology, Magdeburg, Germany
| | - Craig C Garner
- Department of Psychiatry and Behavioral Science, Nancy Pritzker Laboratory, Stanford University, Palo Alto, California, United States of America
| | - Noam E Ziv
- The Rappaport Family Institute for Research in the Medical Sciences, Technion Faculty of Medicine, Haifa, Israel
- The Department of Physiology, Technion Faculty of Medicine, Haifa, Israel
- * To whom correspondence should be addressed. E-mail:
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31
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Gaffield MA, Rizzoli SO, Betz WJ. Mobility of synaptic vesicles in different pools in resting and stimulated frog motor nerve terminals. Neuron 2006; 51:317-25. [PMID: 16880126 DOI: 10.1016/j.neuron.2006.06.031] [Citation(s) in RCA: 81] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2006] [Revised: 05/30/2006] [Accepted: 06/26/2006] [Indexed: 11/27/2022]
Abstract
We used fluorescence recovery after photobleaching (FRAP) to measure the mobility of synaptic vesicles in frog motor nerve terminals. Vesicles belonging to the recycling pool or to the reserve pool were selectively labeled with FM1-43. In resting terminals, vesicles in the reserve pool were immobile, while vesicles in the recycling pool were mobile. Nerve stimulation increased the mobility of reserve pool vesicles. Treatment with latrunculin A, which destroyed actin filaments, had no significant effect on mobility, and reducing the temperature likewise had little effect, suggesting that recycling pool vesicles move by simple diffusion. Application of okadaic acid caused vesicle mobility in both pools to increase to the same level. We could model these and others' results quantitatively by taking into account the relative numbers of mobile and immobile vesicles in each pool, and vesicle packing density, which has a large effect on mobility.
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Affiliation(s)
- Michael A Gaffield
- Neuroscience Program, University of Colorado Medical School, Aurora, Colorado 80045, USA
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32
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Nunes P, Haines N, Kuppuswamy V, Fleet DJ, Stewart BA. Synaptic vesicle mobility and presynaptic F-actin are disrupted in a N-ethylmaleimide-sensitive factor allele of Drosophila. Mol Biol Cell 2006; 17:4709-19. [PMID: 16914524 PMCID: PMC1635382 DOI: 10.1091/mbc.e06-03-0253] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
N-ethylmaleimide sensitive factor (NSF) can dissociate the soluble NSF attachment receptor (SNARE) complex, but NSF also participates in other intracellular trafficking functions by virtue of SNARE-independent activity. Drosophila that express a neural transgene encoding a dominant-negative form of NSF2 show an 80% reduction in the size of releasable synaptic vesicle pool, but no change in the number of vesicles in nerve terminal boutons. Here we tested the hypothesis that vesicles in the NSF2 mutant terminal are less mobile. Using a combination of genetics, pharmacology, and imaging we find a substantial reduction in vesicle mobility within the nerve terminal boutons of Drosophila NSF2 mutant larvae. Subsequent analysis revealed a decrease of filamentous actin in both NSF2 dominant-negative and loss-of-function mutants. Lastly, actin-filament disrupting drugs also decrease vesicle movement. We conclude that a factor contributing to the NSF mutant phenotype is a reduction in vesicle mobility, which is associated with decreased presynaptic F-actin. Our data are consistent with a model in which actin filaments promote vesicle mobility and suggest that NSF participates in establishing or maintaining this population of actin.
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Affiliation(s)
- Paula Nunes
- Department of Biology and Computer Science, University of Toronto, Mississauga, Ontario, Canada
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33
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Schweizer FE, Ryan TA. The synaptic vesicle: cycle of exocytosis and endocytosis. Curr Opin Neurobiol 2006; 16:298-304. [PMID: 16707259 DOI: 10.1016/j.conb.2006.05.006] [Citation(s) in RCA: 102] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2006] [Accepted: 05/05/2006] [Indexed: 11/30/2022]
Abstract
Synaptic vesicles are clustered at the presynaptic terminal where they fuse and recycle in response to stimulation. Vesicles appear to be sorted into pools, but we do not yet understand how physiologically defined pools relate to morphological pools. The advent of dynamic imaging approaches has led to an appreciation of the regulation of vesicle mobility. Newly endocytosed vesicles are highly mobile but appear to become transiently trapped as they re-enter the recycling pool. Recent experiments indicate that endocytosis might have a constant rate, but limited capacity. How endocytosis is linked to exocytosis remains unclear, although calcium emerges as an important player.
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Affiliation(s)
- Felix E Schweizer
- Department of Neurobiology, David Geffen School of Medicine at UCLA, 650 Charles E. Young Drive South, CHS 63-323, Los Angeles, CA 90095-1763, USA.
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34
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Darcy KJ, Staras K, Collinson LM, Goda Y. Constitutive sharing of recycling synaptic vesicles between presynaptic boutons. Nat Neurosci 2006; 9:315-21. [PMID: 16462738 DOI: 10.1038/nn1640] [Citation(s) in RCA: 172] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2005] [Accepted: 01/13/2006] [Indexed: 12/12/2022]
Abstract
The synaptic vesicle cycle is vital for sustained neurotransmitter release. It has been assumed that functional synaptic vesicles are replenished autonomously at individual presynaptic terminals. Here we tested this assumption by using FM dyes in combination with fluorescence recovery after photobleaching and correlative light and electron microscopy in cultured rat hippocampal neurons. After photobleaching, synapses acquired recently recycled FM dye-labeled vesicles originating from nonphotobleached synapses by a process requiring dynamic actin turnover. The imported vesicles entered the functional pool at their host synapses, as revealed by the exocytic release of the dye upon stimulation. FM1-43 photoconversion and ultrastructural analysis confirmed the incorporation of imported vesicles into the presynaptic terminal, where they mixed with the native vesicle pools. Our results demonstrate that synaptic vesicle recycling is not confined to individual presynaptic terminals as is widely believed; rather, a substantial proportion of recycling vesicles are shared constitutively between boutons.
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Affiliation(s)
- Kevin J Darcy
- MRC Laboratory for Molecular Cell Biology and Cell Biology Unit, University College London, Gower Street, London WC1E 6BT, UK
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35
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Shtrahman M, Yeung C, Nauen DW, Bi GQ, Wu XL. Probing vesicle dynamics in single hippocampal synapses. Biophys J 2005; 89:3615-27. [PMID: 16113110 PMCID: PMC1366854 DOI: 10.1529/biophysj.105.059295] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
We use fluorescence correlation spectroscopy and fluorescence recovery after photobleaching to study vesicle dynamics inside the synapses of cultured hippocampal neurons labeled with the fluorescent vesicle marker FM 1-43. These studies show that when the cell is electrically at rest, only a small population of vesicles is mobile, taking seconds to traverse the synapse. Applying the phosphatase inhibitor okadaic acid causes vesicles to diffuse freely, moving 30 times faster than vesicles in control synapses. These results suggest that vesicles move sluggishly due to binding to elements of the synaptic cytomatrix and that this binding is altered by phosphorylation. Motivated by these results, a model is constructed consisting of diffusing vesicles that bind reversibly to the cytomatrix. This stick-and-diffuse model accounts for the fluorescence correlation spectroscopy and fluorescence recovery after photobleaching data, and also predicts the well-known exponential refilling of the readily releasable pool. Our measurements suggest that the movement of vesicles to the active zone is the rate-limiting step in this process.
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Affiliation(s)
- Matthew Shtrahman
- Department of Physics and Astronomy, University of Pittsburgh, Pittsburgh, PA 15260, USA
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36
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Jordan R, Lemke EA, Klingauf J. Visualization of synaptic vesicle movement in intact synaptic boutons using fluorescence fluctuation spectroscopy. Biophys J 2005; 89:2091-102. [PMID: 15980175 PMCID: PMC1366711 DOI: 10.1529/biophysj.105.061663] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Not much is known about the mobility of synaptic vesicles inside small synapses of the central nervous system, reflecting a lack of methods for visualizing these dynamics. We adapted confocal spot detection with fluctuation analysis to monitor the mobility of fluorescently labeled synaptic vesicles inside individual boutons of cultured hippocampal neurons. Using Monte Carlo simulations we were able to propose a simple quantitative model that can describe vesicle mobility in small hippocampal boutons under resting conditions and different pharmacological treatments. We find that vesicle mobility in a time window of 20 s can be well described by caged diffusion (D approximately 5 x 10(-5) microm(2)/s, cage sizes of approximately 50 nm). Mobility can be upregulated by phosphatase blockage and increased further by actin disruption in a dose-dependent manner. Inhibition of the myosin light chain kinase slows down vesicle mobility 10-fold, whereas other kinases like protein kinase C (PKC), A (PKA), and calmodulin kinase II (caMKII) do not affect mobility in unstimulated boutons.
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Affiliation(s)
- Randolf Jordan
- Max-Planck Institute for Biophysical Chemistry, Department of Membrane Biophysics, Am Fassberg 11, 37077 Goettingen, Germany
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37
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Abstract
Communication between cells reaches its highest degree of specialization at chemical synapses. Some synapses talk in a 'whisper'; others 'shout'. The 'louder' the synapse, the more synaptic vesicles are needed to maintain effective transmission, ranging from a few hundred (whisperers) to nearly a million (shouters). These vesicles reside in different 'pools', which have been given a bewildering array of names. In this review, we focus on five tissue preparations in which synaptic vesicle pools have been identified and thoroughly characterized. We argue that, in each preparation, each vesicle can be assigned to one of three distinct pools.
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Affiliation(s)
- Silvio O Rizzoli
- Max-Planck-Institut für biophysikalische Chemie, Göttingen, Germany
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38
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Shakiryanova D, Tully A, Hewes RS, Deitcher DL, Levitan ES. Activity-dependent liberation of synaptic neuropeptide vesicles. Nat Neurosci 2005; 8:173-8. [PMID: 15643430 DOI: 10.1038/nn1377] [Citation(s) in RCA: 93] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2004] [Accepted: 10/26/2004] [Indexed: 11/08/2022]
Abstract
Despite the importance of neuropeptide release, which is evoked by long bouts of action potential activity and which regulates behavior, peptidergic vesicle movement has not been examined in living nerve terminals. Previous in vitro studies have found that secretory vesicle motion at many sites of release is constitutive: Ca(2+) does not affect the movement of small synaptic vesicles in nerve terminals or the movement of large dense core vesicles in growth cones and endocrine cells. However, in vivo imaging of a neuropeptide, atrial natriuretic factor, tagged with green fluorescent protein in larval Drosophila melanogaster neuromuscular junctions shows that peptidergic vesicle behavior in nerve terminals is sensitive to activity-induced Ca(2+) influx. Specifically, peptidergic vesicles are immobile in resting synaptic boutons but become mobile after seconds of stimulation. Vesicle movement is undirected, occurs without the use of axonal transport motors or F-actin, and aids in the depletion of undocked neuropeptide vesicles. Peptidergic vesicle mobilization and post-tetanic potentiation of neuropeptide release are sustained for minutes.
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Affiliation(s)
- Dinara Shakiryanova
- Department of Pharmacology, University of Pittsburgh, Pittsburgh, Pennsylvania 15261, USA
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39
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Robinson DA, Zhuo M. Modulation of presynaptic activity by phosphorylation in cultured rat spinal dorsal horn neurons. THE JOURNAL OF PAIN 2004; 5:329-37. [PMID: 15336637 DOI: 10.1016/j.jpain.2004.05.006] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
UNLABELLED Phosphorylation, in particular by protein kinase C (PKC), modulates spinal sensory transmission and nociceptive behaviors. Whereas PKC's postsynaptic actions are well established, its presynaptic effects in spinal sensory neurons are mostly inferred from postsynaptic recordings. Here we first show that the amphipathic styryl dye FM 1-43 can be used to image presynaptic activity in cultured spinal dorsal horn cultures and then test whether PKC modulates presynaptic activity in cultured spinal dorsal horn neurons. Pretreatment with the broad-spectrum kinase inhibitor staurosporine (2 micromol/L) inhibited dye release. Bisindolylmaleimide I, a PKC inhibitor, potentiated dye release at low doses (200 nmol/L and 1 micromol/L), while inhibiting it at a higher dose (5 micromol/L). Activating PKC with phorbol dibutyrate (0.5 micromol/L) induced an increase in exocytosis, which is partially blocked by bisindolylmaleimide I. These results indicate that styryl dyes can be used to observe presynaptic regulation of spinal dorsal horn neurons, and that PKC acts presynaptically to modulate spinal sensory transmission. PERSPECTIVE With dye imaging technique, we demonstrate here that PKC presynaptically regulates sensory transmission in spinal dorsal horn neurons. In combination with conventional whole-cell patch-clamp recording technique, the present study provides a new methodology for studying spinal sensory transmission and modulation and facilitates our understanding of pain mechanism.
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Affiliation(s)
- Daphné A Robinson
- Washington University Pain Center, Department of Anesthesiology, Washington University School of Medicine, St Louis, Missouri, USA
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40
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Holt M, Cooke A, Neef A, Lagnado L. High mobility of vesicles supports continuous exocytosis at a ribbon synapse. Curr Biol 2004; 14:173-83. [PMID: 14761649 DOI: 10.1016/j.cub.2003.12.053] [Citation(s) in RCA: 112] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2003] [Revised: 12/04/2003] [Accepted: 12/04/2003] [Indexed: 11/29/2022]
Abstract
BACKGROUND Most synapses release neurotransmitter as transient pulses, but ribbon synapses of sensory neurons support continuous exocytosis in response to maintained stimulation. We have investigated how the movement and retrieval of vesicles might contribute to continuous exocytosis at the ribbon synapse of retinal bipolar cells. RESULTS Using a combination of total internal reflection fluorescence microscopy and fluorescence recovery after photobleaching, we found that the great majority of vesicles within 50-120 nm of the plasma membrane move in a random fashion with an effective diffusion coefficient of approximately 1.5 x 10(-2) microm(2) s(-1). Using confocal microscopy, we found that vesicles are similarly mobile across the whole terminal and that this motion is not altered by calcium influx or the actin cytoskeleton. We calculated that the cytoplasmic reservoir of approximately 300,000 vesicles would generate about 900 vesicle collisions/s against ribbons and 28,000 collisions/s against the surface membrane. The efficient resupply of vesicles to ribbons was confirmed by electron microscopy. A 1 min depolarization, releasing 500-1000 vesicles/s, caused a 70% reduction in the number of vesicles docked at the active zone without reducing the number of vesicles attached to ribbons or remote areas of the plasma membrane. These sites were not repopulated by retrieved vesicles because 80-90% of the recycled membrane was taken up into cisternae that pinched off from the surface. CONCLUSIONS These results indicate that the random motion of cytoplasmic vesicles provides an efficient supply to the ribbon and plasma membrane and allows the maintenance of high rates of exocytosis without an equally rapid recycling of vesicles. The selective depletion of vesicles docked under ribbons suggests that the transfer of vesicles to the active zone limits the rate of exocytosis during maintained stimulation.
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Affiliation(s)
- Matthew Holt
- Medical Research Council, Laboratory of Molecular Biology, Hills Road, Cambridge CB2 2QH, United Kingdom
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41
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Rea R, Li J, Dharia A, Levitan ES, Sterling P, Kramer RH. Streamlined Synaptic Vesicle Cycle in Cone Photoreceptor Terminals. Neuron 2004; 41:755-66. [PMID: 15003175 DOI: 10.1016/s0896-6273(04)00088-1] [Citation(s) in RCA: 91] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2003] [Revised: 01/23/2004] [Accepted: 02/10/2004] [Indexed: 10/26/2022]
Abstract
Cone photoreceptors tonically release neurotransmitter in the dark through a continuous cycle of exocytosis and endocytosis. Here, using the synaptic vesicle marker FM1-43, we elucidate specialized features of the vesicle cycle. Unlike retinal bipolar cell terminals, where stimulation triggers bulk membrane retrieval, cone terminals appear to exclusively endocytose small vesicles. These retain their integrity until exocytosis, without pooling their membranes in endosomes. Endocytosed vesicles rapidly disperse through the terminal and are reused with no apparent delay. Unlike other synapses where most vesicles are immobilized and held in reserve, only a small fraction (<15%) becomes immobilized in cones. Photobleaching experiments suggest that vesicles move by diffusion and not by molecular motors on the cytoskeleton and that vesicle movement is not rate limiting for release. The huge reservoir of vesicles that move rapidly throughout cone terminals and the lack of a reserve pool are unique features, providing cones with a steady supply for continuous release.
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Affiliation(s)
- Ruth Rea
- Department of Molecular and Cell Biology, Division of Neurobiology, University of California at Berkeley, Berkeley, CA 94720 USA
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42
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Salazar G, Love R, Werner E, Doucette MM, Cheng S, Levey A, Faundez V. The zinc transporter ZnT3 interacts with AP-3 and it is preferentially targeted to a distinct synaptic vesicle subpopulation. Mol Biol Cell 2003; 15:575-87. [PMID: 14657250 PMCID: PMC329249 DOI: 10.1091/mbc.e03-06-0401] [Citation(s) in RCA: 92] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Synaptic vesicles (SV) are generated by two different mechanisms, one AP-2 dependent and one AP-3 dependent. It has been uncertain, however, whether these mechanisms generate SV that differ in molecular composition. We explored this hypothesis by analyzing the targeting of ZnT3 and synaptophysin both to PC12 synaptic-like microvesicles (SLMV) as well as SV isolated from wild-type and AP-3-deficient mocha brains. ZnT3 cytosolic tail interacted selectively with AP-3 in cell-free assays. Accordingly, pharmacological disruption of either AP-2- or AP-3-dependent SLMV biogenesis preferentially reduced synaptophysin or ZnT3 targeting, respectively; suggesting that these antigens were concentrated in different vesicles. As predicted, immuno-isolated SLMV revealed that ZnT3 and synaptophysin were enriched in different vesicle populations. Likewise, morphological and biochemical analyses in hippocampal neurons indicated that these two antigens were also present in distinct but overlapping domains. ZnT3 SV content was reduced in AP-3-deficient neurons, but synaptophysin was not altered in the AP-3 null background. Our evidence indicates that neuroendocrine cells assemble molecularly heterogeneous SV and suggests that this diversity could contribute to the functional variety of synapses.
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Affiliation(s)
- Gloria Salazar
- Department of Cell Biology, Emory University, Atlanta, Georgia 30322
| | - Rachal Love
- Department of Cell Biology, Emory University, Atlanta, Georgia 30322
| | - Erica Werner
- Department of Cell Biology, Emory University, Atlanta, Georgia 30322
| | | | - Su Cheng
- Department of Cell Biology, Emory University, Atlanta, Georgia 30322
| | - Allan Levey
- Department of Neurology, Emory University, Atlanta, Georgia 30322
- The Center for Neurodegenerative Diseases, Emory University, Atlanta, Georgia 30322
| | - Victor Faundez
- Department of Cell Biology, Emory University, Atlanta, Georgia 30322
- The Center for Neurodegenerative Diseases, Emory University, Atlanta, Georgia 30322
- Corresponding author. E-mail address:
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43
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Abstract
The chemical synapse is a specialized intercellular junction that operates nearly autonomously to allow rapid, specific, and local communication between neurons. Focusing our attention on the presynaptic terminal, we review the current understanding of how synaptic morphology is maintained and then the mechanisms in synaptic vesicle exocytosis and recycling.
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Affiliation(s)
- Venkatesh N Murthy
- Department of Molecular and Cellular Biology, Harvard University, 16 Divinity Avenue, Cambridge, MA 02138, USA.
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44
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Sakaba T, Neher E. Involvement of actin polymerization in vesicle recruitment at the calyx of Held synapse. J Neurosci 2003; 23:837-46. [PMID: 12574412 PMCID: PMC6741913] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/28/2023] Open
Abstract
Depletion and replenishment of pools of synaptic vesicles are important determinants of short-term synaptic plasticity, but the underlying molecular mechanisms are not yet clear. As a first step toward understanding the process of vesicle recruitment, we have applied various specific agents directly to the presynaptic terminal of the calyx of Held synapse. Here we show that the nonhydrolyzable ATP analog ATP-gammaS retards the recovery from vesicle pool depletion, as does latrunculin A. Phalloidin has no effects on recovery, suggesting that dynamic actin reorganization is not necessary. Unexpectedly, neither N-ethylmaleimide nor staurosporine affected the recovery, calling into question the role of N-ethylmaleimide-sensitive factor and protein kinases. The results suggest that intact actin polymerization is involved in vesicle recruitment.
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Affiliation(s)
- Takeshi Sakaba
- Department of Membrane Biophysics, Max-Planck-Institute for Biophysical Chemistry, Göttingen, D-37077, Germany
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45
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Guatimosim C, Hull C, Von Gersdorff H, Prado MAM. Okadaic acid disrupts synaptic vesicle trafficking in a ribbon-type synapse. J Neurochem 2002; 82:1047-57. [PMID: 12358752 PMCID: PMC3572837 DOI: 10.1046/j.1471-4159.2002.01029.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Protein phosphorylation plays an essential role in regulating synaptic transmission and plasticity. However, regulation of vesicle trafficking towards and away from the plasma membrane is poorly understood. Furthermore, the extent to which phosphorylation modulates ribbon-type synapses is unknown. Using the phosphatase inhibitor okadaic acid (OA), we investigated the influence of persistent phosphorylation on vesicle cycling in goldfish bipolar cells. We followed uptake of FM1-43 during vesicle recycling in control and OA-treated cells. FM1-43 fluorescence spread to the center of control synaptic terminals after depolarization elicited Ca2+ influx. However, OA (1-50 nm) impaired this spatial spread of FM1-43 in a dose-dependent manner. Capacitance measurements revealed that OA (50 nm) did not modify either the amount or kinetics of exocytosis and endocytosis evoked by depolarizing pulses. The extremely low concentrations of OA (1-5 nm) sufficient to observe the inhibition of vesicle mobility implicate phosphatase 2A (PP2A) as a major regulator of vesicle trafficking after endocytosis. These results contrast with those at the neuromuscular junction where OA enhances lateral movement of vesicles between distinct vesicle clusters. Thus, our results suggest that phosphatases regulate vesicle translocation at ribbon synapses in a different manner than conventional active zones.
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Affiliation(s)
- Cristina Guatimosim
- Departmento de Farmacologia, ICB, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil.
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46
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Zhang W, Benson DL. Developmentally regulated changes in cellular compartmentation and synaptic distribution of actin in hippocampal neurons. J Neurosci Res 2002; 69:427-36. [PMID: 12210837 DOI: 10.1002/jnr.10313] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Actin dynamics and actin-based motility are important for neurite outgrowth and synapse plasticity. Recent work implicates actin in synapse assembly, but the morphological relationship between actin and synapses during development is unclear. Here we used developing hippocampal neurons grown in culture to examine the relationship between F- and G-actin and clusters of synaptic proteins. Both F- and G-actin are most enriched in dendritic and axonal growth cones, but only G-actin is present within the distal tips of filopodia. Outside of growth cones, F-actin levels are greater in dendrites than in axons, whereas G-actin levels are slightly greater in axons than in dendrites. The distribution of both F- and G-actin is consistent with their presence at synapses, but only F-actin levels become detectably enhanced at synaptic sites. Quantitative analyses suggest that first-forming synapses are associated with enhanced levels of pre- and postsynaptic F-actin that do not necessarily remain elevated during synapse maturation. However, nearly all mature excitatory synapses become associated with high, mostly postsynaptic concentrations of F-actin contained principally within dendritic spines. Mature shaft and GABAergic synapses are also associated with enhanced levels of F-actin, but to a lesser degree. Thus, although F-actin is essential for function and maintenance of young synapses, it need not be highly concentrated at every site. The large increase in postsynaptic F-actin concentration observed in mature neurons is likely to reflect actin's role in dendritic spine morphology and in synapse plasticity.
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Affiliation(s)
- Wandong Zhang
- Fishberg Research Center for Neurobiology, The Mount Sinai School of Medicine, New York, New York 10029, USA
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47
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Congar P, Trudeau LE. Perturbation of synaptic vesicle delivery during neurotransmitter release triggered independently of calcium influx. J Physiol 2002; 542:779-93. [PMID: 12154178 PMCID: PMC2290460 DOI: 10.1113/jphysiol.2002.020222] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
Although much evidence suggests that calcium (Ca(2+)) usually triggers synaptic vesicle exocytosis and neurotransmitter release, the role of Ca(2+) in vesicle endocytosis and in the delivery of fusion-competent vesicles (i.e. mobilisation and/or priming) in nerve terminals remains unclear. To address this issue, we have studied synaptic vesicle dynamics in cultured rat neurones under conditions where neurotransmitter release is triggered independently of Ca(2+) using the secretagogue Ruthenium Red (RR). Using a prolonged stimulation protocol, we find that RR causes a rapid increase in neurotransmitter release followed by a gradually decrementing response. In contrast, when release is triggered by moderate membrane depolarisation caused by saline containing 18 mM K(+), release is sustained. These observations suggest that when release is triggered independently of a rise in Ca(2+), endocytosis or vesicle mobilisation/priming are perturbed. Using FM2-10, a fluorescent indicator of synaptic vesicle cycling, we find that neurotransmitter release triggered by RR is accompanied by both uptake and release of this dye, thereby suggesting that vesicle endocytosis is not blocked. To evaluate whether synaptic vesicle mobilisation/priming is perturbed in the absence of a rise in Ca(2+), we compared the kinetics of FM2-10 loss during prolonged stimulation. While 18 mM K(+) induced gradual and continuous dye loss, RR only induced substantial dye loss during the first minute of stimulation. In the presence of low concentrations of the Ca(2+) ionophore ionomycin, release caused by RR was prolonged. Taken together, these results provide evidence suggesting that, although a rise in intraterminal Ca(2+) is not required for endocytosis, it is essential for the continuous delivery of fusion-competent vesicles and to maintain neurotransmitter release during prolonged stimulation.
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Affiliation(s)
- Patrice Congar
- Département de Pharmacologie, Centre de Recherche en Sciences Neurologiques and Centre de Recherche Fernand Seguin, Faculté de Médecine, Université de Montréal, Québec, Canada
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Christie SB, Miralles CP, De Blas AL. GABAergic innervation organizes synaptic and extrasynaptic GABAA receptor clustering in cultured hippocampal neurons. J Neurosci 2002; 22:684-97. [PMID: 11826098 PMCID: PMC6758471] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2001] [Revised: 10/16/2001] [Accepted: 11/09/2001] [Indexed: 02/23/2023] Open
Abstract
We have studied the effects of GABAergic innervation on the clustering of GABA(A) receptors (GABA(A)Rs) in cultured hippocampal neurons. In the absence of GABAergic innervation, pyramidal cells form small (0.36 +/- 0.01 micrometer diameter) GABA(A)R clusters at their surface in the dendrites and soma. When receiving GABAergic innervation from glutamic acid decarboxylase-containing interneurons, pyramidal cells form large (1.62 +/- 0.08 micrometer breadth) GABA(A)R clusters at GABAergic synapses. This is accompanied by a disappearance of the small GABA(A)R clusters in the local area surrounding each GABAergic synapse. Although the large synaptic GABA(A)R clusters of any neuron contained all GABA(A)R subunits and isoforms expressed by that neuron, the small clusters not localized at GABAergic synapses showed significant heterogeneity in subunit and isoform composition. Another difference between large GABAergic and small non-GABAergic GABA(A)R clusters was that a significant proportion of the latter was juxtaposed to postsynaptic markers of glutamatergic synapses such as PSD-95 and AMPA receptor GluR1 subunit. The densities of both the glutamate receptor-associated and non-associated small GABA(A)R clusters were decreased in areas surrounding GABAergic synapses. However, no effect on the density or distribution of glutamate receptor clusters was observed. The results suggest that there are local signals generated at GABAergic synapses that induce both assembly of large synaptic GABA(A)R clusters at the synapse and disappearance of the small GABA(A)R clusters in the surrounding area. In the absence of GABAergic innervation, weaker GABA(A)R-clustering signals, generated at glutamatergic synapses, induce the formation of small postsynaptic GABA(A)R clusters that remain juxtaposed to glutamate receptors at glutamatergic synapses.
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Affiliation(s)
- Sean B Christie
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, Connecticut 06269, USA
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Abstract
We have investigated mechanisms in postendocytic processing of synaptic vesicles at hippocampal synapses, using synaptobrevin/vesicle-associated membrane protein (VAMP) tagged with variants of the green fluorescent protein. Following exocytosis, VAMP is retrieved at synaptic and adjoining axonal regions. Retrieved VAMP-containing vesicles return to synaptic vesicle clusters at a rate slower than endocytosis. Vesicles containing a different protein, synaptophysin, recluster at a similar rate, suggesting common vesicular intermediates for the two proteins. Activity prolongs the time taken by endocytosed vesicles to return to synapses. Exogenous calcium buffers slow endocytosis but have no additional effect on the time course of reclustering. In contrast, the protein kinase inhibitor staurosporine does not affect endocytosis but slows reclustering. Finally, since VAMP can move freely on surface membranes, sustained synaptic activity leads to mixing of this vesicular component between adjacent synapses.
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Affiliation(s)
- Z Li
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA 02138, USA
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Abstract
The dynamics of axonal arbors during synaptogenesis and their plasticity in the adult nervous system remain poorly understood. Axonal filopodia, which emerge from the shaft of axonal branches and contain small synaptic vesicle clusters, initiate synaptic formation. We found that the movement of axonal filopodia is strongly inhibited by the neurotransmitter glutamate. This inhibitory effect is local, requires extracellular Ca2+, and can be blocked by CNQX treatment but not by NMDA, implicating axonal AMPA/kainate glutamate receptors. Transport and exo-endocytic recycling of synaptic vesicle packages in filopodia are not affected. These results reveal that the effect of glutamate on axonal filopodia is similar to its previously described effect on dendritic spines. Our results raise the possibility that axonal ionotropic glutamate receptors are also involved in synaptic plasticity in the adult nervous system.
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MESH Headings
- Actins/antagonists & inhibitors
- Actins/genetics
- Actins/metabolism
- Animals
- Bridged Bicyclo Compounds, Heterocyclic/pharmacology
- Calcium/metabolism
- Calcium Channels/drug effects
- Calcium Channels/metabolism
- Cell Differentiation/drug effects
- Cell Differentiation/physiology
- Cell Movement/drug effects
- Cell Movement/physiology
- Cells, Cultured/cytology
- Cells, Cultured/drug effects
- Cells, Cultured/metabolism
- Central Nervous System/cytology
- Central Nervous System/embryology
- Central Nervous System/metabolism
- Glutamic Acid/drug effects
- Glutamic Acid/metabolism
- Green Fluorescent Proteins
- Growth Cones/drug effects
- Growth Cones/metabolism
- Growth Cones/ultrastructure
- Hippocampus/cytology
- Hippocampus/drug effects
- Hippocampus/metabolism
- Immunohistochemistry
- Luminescent Proteins/genetics
- Neuronal Plasticity/drug effects
- Neuronal Plasticity/genetics
- Pseudopodia/drug effects
- Pseudopodia/metabolism
- Pseudopodia/ultrastructure
- Rats
- Receptors, AMPA/agonists
- Receptors, AMPA/antagonists & inhibitors
- Receptors, AMPA/metabolism
- Receptors, N-Methyl-D-Aspartate/agonists
- Receptors, N-Methyl-D-Aspartate/antagonists & inhibitors
- Receptors, N-Methyl-D-Aspartate/metabolism
- Thiazoles/pharmacology
- Thiazolidines
- tau Proteins/metabolism
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Affiliation(s)
- S Chang
- Howard Hughes Medical Institute and Department of Cell Biology, Boyer Center for Molecular Medicine, Yale University School of Medicine, 295 Congress Avenue, PO Box 9812, New Haven, Connecticut 06515, USA
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