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Pribicevic S, Graham AC, Cafiso DS, Pérez-Lara Á, Jahn R. Intermediate steps in the formation of neuronal SNARE complexes. J Biol Chem 2024; 300:107591. [PMID: 39032647 PMCID: PMC11381810 DOI: 10.1016/j.jbc.2024.107591] [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: 10/02/2023] [Revised: 05/06/2024] [Accepted: 07/11/2024] [Indexed: 07/23/2024] Open
Abstract
Neuronal exocytosis requires the assembly of three SNARE proteins, syntaxin and SNAP25 on the plasma membrane and synaptobrevin on the vesicle membrane. However, the precise steps in this process and the points at which assembly and fusion are controlled by regulatory proteins are unclear. In the present work, we examine the kinetics and intermediate states during SNARE assembly in vitro using a combination of time resolved fluorescence and EPR spectroscopy. We show that syntaxin rapidly forms a dimer prior to forming the kinetically stable 2:1 syntaxin:SNAP25 complex and that the 2:1 complex is not diminished by the presence of excess SNAP25. Moreover, the 2:1 complex is temperature-dependent with a reduced concentration at 37 °C. The two segments of SNAP25 behave differently. The N-terminal SN1 segment of SNAP25 exhibits a pronounced increase in backbone ordering from the N- to the C-terminus that is not seen in the C-terminal SNAP25 segment SN2. Both the SN1 and SN2 segments of SNAP25 will assemble with syntaxin; however, while the association of the SN1 segment with syntaxin produces a stable 2:2 (SN1:syntaxin) complex, the complex formed between SN2 and syntaxin is largely disordered. Synaptobrevin fails to bind syntaxin alone but will associate with syntaxin in the presence of either the SN1 or SN2 segments; however, the synaptobrevin:syntaxin:SN2 complex remains disordered. Taken together, these data suggest that synaptobrevin and syntaxin do not assemble in the absence of SNAP25 and that the SN2 segment of SNAP25 is the last to enter the SNARE complex.
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Affiliation(s)
- Sonja Pribicevic
- Laboratory of Neurobiology, Max-Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
| | - Abigail C Graham
- Department of Chemistry, University of Virginia, Charlottesville, Virginia, USA
| | - David S Cafiso
- Department of Chemistry, University of Virginia, Charlottesville, Virginia, USA.
| | - Ángel Pérez-Lara
- Laboratory of Neurobiology, Max-Planck Institute for Multidisciplinary Sciences, Göttingen, Germany; Department of Physical Chemistry, Faculty of Pharmacy, University of Granada, Granada, Spain.
| | - Reinhard Jahn
- Laboratory of Neurobiology, Max-Planck Institute for Multidisciplinary Sciences, Göttingen, Germany.
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Leitz J, Wang C, Esquivies L, Peters JJ, Gopal N, Pfuetzner RA, Wang AL, Brunger AT. Observing isolated synaptic vesicle association and fusion ex vivo. Nat Protoc 2024:10.1038/s41596-024-01014-x. [PMID: 38956381 DOI: 10.1038/s41596-024-01014-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2022] [Accepted: 05/15/2024] [Indexed: 07/04/2024]
Abstract
Here, we present a protocol for isolating functionally intact glutamatergic synaptic vesicles from whole-mouse brain tissue and using them in a single-vesicle assay to examine their association and fusion with plasma membrane mimic vesicles. This is a Protocol Extension, building on our previous protocol, which used a purely synthetic system comprised of reconstituted proteins in liposomes. We also describe the generation of a peptide based on the vesicular glutamate transporter, which is essential in the isolation process of glutamatergic synaptic vesicles. This method uses easily accessible reagents to generate fusion-competent glutamatergic synaptic vesicles through immunoisolation. The generation of the vGlut peptide can be accomplished in 6 d, while the isolation of the synaptic vesicles by using the peptide can be accomplished in 2 d, with an additional day to fluorescently label the synaptic vesicles for use in a single-vesicle hybrid fusion assay. The single-vesicle fusion assay can be accomplished in 1 d and can unambiguously delineate synaptic vesicle association, dissociation, Ca2+-independent and Ca2+-dependent fusion modalities. This assay grants control of the synaptic vesicle environment while retaining the complexity of the synaptic vesicles themselves. This protocol can be adapted to studies of other types of synaptic vesicles or, more generally, different secretory or transport vesicles. The workflow described here requires expertise in biochemistry techniques, in particular, protein purification and fluorescence imaging. We assume that the laboratory has protein-purification equipment, including chromatography systems.
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Affiliation(s)
- Jeremy Leitz
- Department of Molecular and Cellular Physiology, Stanford University, Stanford, CA, USA
- Department of Neurology and Neurological Sciences, Stanford University, Stanford, CA, USA
- Department of Structural Biology, Stanford University, Stanford, CA, USA
- Department of Photon Science, Stanford University, Stanford, CA, USA
- Howard Hughes Medical Institute, Stanford University, Stanford, CA, USA
| | - Chuchu Wang
- Department of Molecular and Cellular Physiology, Stanford University, Stanford, CA, USA
- Department of Neurology and Neurological Sciences, Stanford University, Stanford, CA, USA
- Department of Structural Biology, Stanford University, Stanford, CA, USA
- Department of Photon Science, Stanford University, Stanford, CA, USA
- Howard Hughes Medical Institute, Stanford University, Stanford, CA, USA
| | - Luis Esquivies
- Department of Molecular and Cellular Physiology, Stanford University, Stanford, CA, USA
- Department of Neurology and Neurological Sciences, Stanford University, Stanford, CA, USA
- Department of Structural Biology, Stanford University, Stanford, CA, USA
- Department of Photon Science, Stanford University, Stanford, CA, USA
- Howard Hughes Medical Institute, Stanford University, Stanford, CA, USA
| | - John J Peters
- Department of Molecular and Cellular Physiology, Stanford University, Stanford, CA, USA
- Department of Neurology and Neurological Sciences, Stanford University, Stanford, CA, USA
- Department of Structural Biology, Stanford University, Stanford, CA, USA
- Department of Photon Science, Stanford University, Stanford, CA, USA
- Howard Hughes Medical Institute, Stanford University, Stanford, CA, USA
| | - Nisha Gopal
- Department of Molecular and Cellular Physiology, Stanford University, Stanford, CA, USA
- Department of Neurology and Neurological Sciences, Stanford University, Stanford, CA, USA
- Department of Structural Biology, Stanford University, Stanford, CA, USA
- Department of Photon Science, Stanford University, Stanford, CA, USA
- Howard Hughes Medical Institute, Stanford University, Stanford, CA, USA
| | - Richard A Pfuetzner
- Department of Molecular and Cellular Physiology, Stanford University, Stanford, CA, USA
- Department of Neurology and Neurological Sciences, Stanford University, Stanford, CA, USA
- Department of Structural Biology, Stanford University, Stanford, CA, USA
- Department of Photon Science, Stanford University, Stanford, CA, USA
- Howard Hughes Medical Institute, Stanford University, Stanford, CA, USA
| | - Austin L Wang
- Department of Molecular and Cellular Physiology, Stanford University, Stanford, CA, USA
- Department of Neurology and Neurological Sciences, Stanford University, Stanford, CA, USA
- Department of Structural Biology, Stanford University, Stanford, CA, USA
- Department of Photon Science, Stanford University, Stanford, CA, USA
- Howard Hughes Medical Institute, Stanford University, Stanford, CA, USA
| | - Axel T Brunger
- Department of Molecular and Cellular Physiology, Stanford University, Stanford, CA, USA.
- Department of Neurology and Neurological Sciences, Stanford University, Stanford, CA, USA.
- Department of Structural Biology, Stanford University, Stanford, CA, USA.
- Department of Photon Science, Stanford University, Stanford, CA, USA.
- Howard Hughes Medical Institute, Stanford University, Stanford, CA, USA.
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Weichard I, Taschenberger H, Gsell F, Bornschein G, Ritzau-Jost A, Schmidt H, Kittel RJ, Eilers J, Neher E, Hallermann S, Nerlich J. Fully-primed slowly-recovering vesicles mediate presynaptic LTP at neocortical neurons. Proc Natl Acad Sci U S A 2023; 120:e2305460120. [PMID: 37856547 PMCID: PMC10614622 DOI: 10.1073/pnas.2305460120] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2023] [Accepted: 08/26/2023] [Indexed: 10/21/2023] Open
Abstract
Pre- and postsynaptic forms of long-term potentiation (LTP) are candidate synaptic mechanisms underlying learning and memory. At layer 5 pyramidal neurons, LTP increases the initial synaptic strength but also short-term depression during high-frequency transmission. This classical form of presynaptic LTP has been referred to as redistribution of synaptic efficacy. However, the underlying mechanisms remain unclear. We therefore performed whole-cell recordings from layer 5 pyramidal neurons in acute cortical slices of rats and analyzed presynaptic function before and after LTP induction by paired pre- and postsynaptic neuronal activity. LTP was successfully induced in about half of the synaptic connections tested and resulted in increased synaptic short-term depression during high-frequency transmission and a decelerated recovery from short-term depression due to an increased fraction of a slow recovery component. Analysis with a recently established sequential two-step vesicle priming model indicates an increase in the abundance of fully-primed and slowly-recovering vesicles. A systematic analysis of short-term plasticity and synapse-to-synapse variability of synaptic strength at various types of synapses revealed that stronger synapses generally recover more slowly from synaptic short-term depression. Finally, pharmacological stimulation of the cyclic adenosine monophosphate and diacylglycerol signaling pathways, which are both known to promote synaptic vesicle priming, mimicked LTP and slowed the recovery from short-term depression. Our data thus demonstrate that LTP at layer 5 pyramidal neurons increases synaptic strength primarily by enlarging a subpool of fully-primed slowly-recovering vesicles.
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Affiliation(s)
- Iron Weichard
- Faculty of Medicine, Carl-Ludwig-Institute for Physiology, Leipzig University, Leipzig04103, Germany
| | - Holger Taschenberger
- Department of Molecular Neurobiology, Max Planck Institute for Multidisciplinary Sciences, Göttingen37075, Germany
| | - Felix Gsell
- Faculty of Medicine, Carl-Ludwig-Institute for Physiology, Leipzig University, Leipzig04103, Germany
| | - Grit Bornschein
- Faculty of Medicine, Carl-Ludwig-Institute for Physiology, Leipzig University, Leipzig04103, Germany
| | - Andreas Ritzau-Jost
- Faculty of Medicine, Carl-Ludwig-Institute for Physiology, Leipzig University, Leipzig04103, Germany
| | - Hartmut Schmidt
- Faculty of Medicine, Carl-Ludwig-Institute for Physiology, Leipzig University, Leipzig04103, Germany
| | - Robert J. Kittel
- Department of Animal Physiology, Institute of Biology, Leipzig University, Leipzig04103, Germany
| | - Jens Eilers
- Faculty of Medicine, Carl-Ludwig-Institute for Physiology, Leipzig University, Leipzig04103, Germany
| | - Erwin Neher
- Emeritus Laboratory of Membrane Biophysics, Max Planck Institute for Multidisciplinary Sciences, Göttingen37070, Germany
- Cluster of Excellence “Multiscale Bioimaging: From Molecular Machines to Networks of Excitable Cells”, University of Göttingen, Göttingen37073, Germany
| | - Stefan Hallermann
- Faculty of Medicine, Carl-Ludwig-Institute for Physiology, Leipzig University, Leipzig04103, Germany
| | - Jana Nerlich
- Faculty of Medicine, Carl-Ludwig-Institute for Physiology, Leipzig University, Leipzig04103, Germany
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Maneu V, Borges R, Gandía L, García AG. Forty years of the adrenal chromaffin cell through ISCCB meetings around the world. Pflugers Arch 2023; 475:667-690. [PMID: 36884064 PMCID: PMC10185644 DOI: 10.1007/s00424-023-02793-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2022] [Revised: 01/20/2023] [Accepted: 01/28/2023] [Indexed: 03/09/2023]
Abstract
This historical review focuses on the evolution of the knowledge accumulated during the last two centuries on the biology of the adrenal medulla gland and its chromaffin cells (CCs). The review emerged in the context of a series of meetings that started on the Spanish island of Ibiza in 1982 with the name of the International Symposium on Chromaffin Cell Biology (ISCCB). Hence, the review is divided into two periods namely, before 1982 and from this year to 2022, when the 21st ISCCB meeting was just held in Hamburg, Germany. The first historical period extends back to 1852 when Albert Kölliker first described the fine structure and function of the adrenal medulla. Subsequently, the adrenal staining with chromate salts identified the CCs; this was followed by the establishment of the embryological origin of the adrenal medulla, and the identification of adrenaline-storing vesicles. By the end of the nineteenth century, the basic morphology, histochemistry, and embryology of the adrenal gland were known. The twentieth century began with breakthrough findings namely, the experiment of Elliott suggesting that adrenaline was the sympathetic neurotransmitter, the isolation of pure adrenaline, and the deciphering of its molecular structure and chemical synthesis in the laboratory. In the 1950s, Blaschko isolated the catecholamine-storing vesicles from adrenal medullary extracts. This switched the interest in CCs as models of sympathetic neurons with an explosion of studies concerning their functions, i.e., uptake of catecholamines by chromaffin vesicles through a specific coupled transport system; the identification of several vesicle components in addition to catecholamines including chromogranins, ATP, opioids, and other neuropeptides; the calcium-dependence of the release of catecholamines; the underlying mechanism of exocytosis of this release, as indicated by the co-release of proteins; the cross-talk between the adrenal cortex and the medulla; and the emission of neurite-like processes by CCs in culture, among other numerous findings. The 1980s began with the introduction of new high-resolution techniques such as patch-clamp, calcium probes, marine toxins-targeting ion channels and receptors, confocal microscopy, or amperometry. In this frame of technological advances at the Ibiza ISCCB meeting in 1982, 11 senior researchers in the field predicted a notable increase in our knowledge in the field of CCs and the adrenal medulla; this cumulative knowledge that occurred in the last 40 years of history of the CC is succinctly described in the second part of this historical review. It deals with cell excitability, ion channel currents, the exocytotic fusion pore, the handling of calcium ions by CCs, the kinetics of exocytosis and endocytosis, the exocytotic machinery, and the life cycle of secretory vesicles. These concepts together with studies on the dynamics of membrane fusion with super-resolution imaging techniques at the single-protein level were extensively reviewed by top scientists in the field at the 21st ISCCB meeting in Hamburg in the summer of 2022; this frontier topic is also briefly reviewed here. Many of the concepts arising from those studies contributed to our present understanding of synaptic transmission. This has been studied in physiological or pathophysiological conditions, in CCs from animal disease models. In conclusion, the lessons we have learned from CC biology as a peripheral model for brain and brain disease pertain more than ever to cutting-edge research in neurobiology. In the 22nd ISCCB meeting in Israel in 2024 that Uri Asheri is organizing, we will have the opportunity of seeing the progress of the questions posed in Ibiza, and on other questions that undoubtedly will arise.
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Affiliation(s)
- Victoria Maneu
- Departamento de Óptica, Farmacología y Anatomía, Universidad de Alicante, Alicante, Spain
| | - Ricardo Borges
- Unidad de Farmacología, Departamento de Medicina Física y Farmacología, Facultad de Medicina, Universidad de La Laguna, Tenerife, Spain
| | - Luis Gandía
- Instituto Fundación Teófilo Hernando, Madrid, Spain
- Departamento de Farmacología y Terapéutica, Universidad Autónoma de Madrid, Madrid, Spain
| | - Antonio G. García
- Instituto Fundación Teófilo Hernando, Madrid, Spain
- Departamento de Farmacología y Terapéutica, Universidad Autónoma de Madrid, Madrid, Spain
- Facultad de Medicina, Instituto de Investigación Sanitaria del Hospital Universitario La Princesa, Universidad Autónoma de Madrid, Madrid, Spain
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