1
|
Li J, Huang X, An Y, Chen X, Chen Y, Xu M, Shan H, Zhang M. The role of snapin in regulation of brain homeostasis. Neural Regen Res 2024; 19:1696-1701. [PMID: 38103234 PMCID: PMC10960280 DOI: 10.4103/1673-5374.389364] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2023] [Revised: 09/15/2023] [Accepted: 10/08/2023] [Indexed: 12/18/2023] Open
Abstract
Brain homeostasis refers to the normal working state of the brain in a certain period, which is important for overall health and normal life activities. Currently, there is a lack of effective treatment methods for the adverse consequences caused by brain homeostasis imbalance. Snapin is a protein that assists in the formation of neuronal synapses and plays a crucial role in the normal growth and development of synapses. Recently, many researchers have reported the association between snapin and neurologic and psychiatric disorders, demonstrating that snapin can improve brain homeostasis. Clinical manifestations of brain disease often involve imbalances in brain homeostasis and may lead to neurological and behavioral sequelae. This article aims to explore the role of snapin in restoring brain homeostasis after injury or diseases, highlighting its significance in maintaining brain homeostasis and treating brain diseases. Additionally, it comprehensively discusses the implications of snapin in other extracerebral diseases such as diabetes and viral infections, with the objective of determining the clinical potential of snapin in maintaining brain homeostasis.
Collapse
Affiliation(s)
- Jiawen Li
- Shanghai Key Lab of Forensic Medicine, Key Lab of Forensic Science, Ministry of Justice, China (Academy of Forensic Science), Shanghai, China
- Institute of Forensic Sciences, Suzhou Medical College, Soochow University, Suzhou, Jiangsu Province, China
| | - Xinqi Huang
- Institute of Forensic Sciences, Suzhou Medical College, Soochow University, Suzhou, Jiangsu Province, China
| | - Yumei An
- Institute of Forensic Sciences, Suzhou Medical College, Soochow University, Suzhou, Jiangsu Province, China
| | - Xueshi Chen
- Institute of Forensic Sciences, Suzhou Medical College, Soochow University, Suzhou, Jiangsu Province, China
| | - Yiyang Chen
- Institute of Forensic Sciences, Suzhou Medical College, Soochow University, Suzhou, Jiangsu Province, China
| | - Mingyuan Xu
- Institute of Forensic Sciences, Suzhou Medical College, Soochow University, Suzhou, Jiangsu Province, China
| | - Haiyan Shan
- Department of Obstetrics and Gynecology, The Affiliated Suzhou Hospital of Nanjing Medical University, Suzhou, Jiangsu Province, China
| | - Mingyang Zhang
- Shanghai Key Lab of Forensic Medicine, Key Lab of Forensic Science, Ministry of Justice, China (Academy of Forensic Science), Shanghai, China
- Institute of Forensic Sciences, Suzhou Medical College, Soochow University, Suzhou, Jiangsu Province, China
| |
Collapse
|
2
|
Lolicato F, Nickel W, Haucke V, Ebner M. Phosphoinositide switches in cell physiology - From molecular mechanisms to disease. J Biol Chem 2024; 300:105757. [PMID: 38364889 PMCID: PMC10944118 DOI: 10.1016/j.jbc.2024.105757] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2023] [Revised: 02/02/2024] [Accepted: 02/08/2024] [Indexed: 02/18/2024] Open
Abstract
Phosphoinositides are amphipathic lipid molecules derived from phosphatidylinositol that represent low abundance components of biological membranes. Rather than serving as mere structural elements of lipid bilayers, they represent molecular switches for a broad range of biological processes, including cell signaling, membrane dynamics and remodeling, and many other functions. Here, we focus on the molecular mechanisms that turn phosphoinositides into molecular switches and how the dysregulation of these processes can lead to disease.
Collapse
Affiliation(s)
- Fabio Lolicato
- Heidelberg University Biochemistry Center, Heidelberg, Germany; Department of Physics, University of Helsinki, Helsinki, Finland.
| | - Walter Nickel
- Heidelberg University Biochemistry Center, Heidelberg, Germany
| | - Volker Haucke
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), Berlin, Germany; Department of Biology, Chemistry, Pharmacy, Freie Universität Berlin, Berlin, Germany; Charité - Universitätsmedizin Berlin, Berlin, Germany
| | - Michael Ebner
- Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), Berlin, Germany.
| |
Collapse
|
3
|
Kessi M, Peng J, He F, Yin F, Ferreira SG, Wei X. Editorial: 90th anniversary of the 1932 Sherrington and Adrian Nobel prize: molecular pathways of synaptic transmission regulation. Front Mol Neurosci 2023; 16:1271369. [PMID: 37675142 PMCID: PMC10478231 DOI: 10.3389/fnmol.2023.1271369] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2023] [Accepted: 08/10/2023] [Indexed: 09/08/2023] Open
Affiliation(s)
- Miriam Kessi
- Xiangya Hospital, Central South University, Changsha, China
- Clinical Research Center for Children Neurodevelopmental Disabilities of Hunan Province, Changsha, China
| | - Jing Peng
- Xiangya Hospital, Central South University, Changsha, China
- Clinical Research Center for Children Neurodevelopmental Disabilities of Hunan Province, Changsha, China
| | - Fang He
- Xiangya Hospital, Central South University, Changsha, China
- Clinical Research Center for Children Neurodevelopmental Disabilities of Hunan Province, Changsha, China
| | - Fei Yin
- Xiangya Hospital, Central South University, Changsha, China
- Clinical Research Center for Children Neurodevelopmental Disabilities of Hunan Province, Changsha, China
| | - Samira G. Ferreira
- Centre for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal
| | - Xiaofei Wei
- David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, United States
| |
Collapse
|
4
|
Bykhovskaia M. Molecular Dynamics Simulations of the Proteins Regulating Synaptic Vesicle Fusion. MEMBRANES 2023; 13:307. [PMID: 36984694 PMCID: PMC10058449 DOI: 10.3390/membranes13030307] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/23/2023] [Revised: 02/11/2023] [Accepted: 03/01/2023] [Indexed: 06/18/2023]
Abstract
Neuronal transmitters are packaged in synaptic vesicles (SVs) and released by the fusion of SVs with the presynaptic membrane (PM). An inflow of Ca2+ into the nerve terminal triggers fusion, and the SV-associated protein Synaptotagmin 1 (Syt1) serves as a Ca2+ sensor. In preparation for fusion, SVs become attached to the PM by the SNARE protein complex, a coiled-coil bundle that exerts the force overcoming SV-PM repulsion. A cytosolic protein Complexin (Cpx) attaches to the SNARE complex and differentially regulates the evoked and spontaneous release components. It is still debated how the dynamic interactions of Syt1, SNARE proteins and Cpx lead to fusion. This problem is confounded by heterogeneity in the conformational states of the prefusion protein-lipid complex and by the lack of tools to experimentally monitor the rapid conformational transitions of the complex, which occur at a sub-millisecond scale. However, these complications can be overcome employing molecular dynamics (MDs), a computational approach that enables simulating interactions and conformational transitions of proteins and lipids. This review discusses the use of molecular dynamics for the investigation of the pre-fusion protein-lipid complex. We discuss the dynamics of the SNARE complex between lipid bilayers, as well as the interactions of Syt1 with lipids and SNARE proteins, and Cpx regulating the assembly of the SNARE complex.
Collapse
Affiliation(s)
- Maria Bykhovskaia
- Neurology Department, Wayne State University, Detroit, MI 48202, USA
| |
Collapse
|
5
|
Lottermoser JA, Dittman JS. Complexin Membrane Interactions: Implications for Synapse Evolution and Function. J Mol Biol 2023; 435:167774. [PMID: 35931110 PMCID: PMC9807284 DOI: 10.1016/j.jmb.2022.167774] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2022] [Revised: 07/27/2022] [Accepted: 07/28/2022] [Indexed: 02/04/2023]
Abstract
The molecules and mechanisms behind chemical synaptic transmission have been explored for decades. For several of the core proteins involved in synaptic vesicle fusion, we now have a reasonably detailed grasp of their biochemical, structural, and functional properties. Complexin is one of the key synaptic proteins for which a simple mechanistic understanding is still lacking. Living up to its name, this small protein has been associated with a variety of roles differing between synapses and between species, but little consensus has been reached on its fundamental modes of action. Much attention has been paid to its deeply conserved SNARE-binding properties, while membrane-binding features of complexin and their functional significance have yet to be explored to the same degree. In this review, we summarize the known membrane interactions of the complexin C-terminal domain and their potential relevance to its function, synaptic localization, and evolutionary history.
Collapse
Affiliation(s)
| | - Jeremy S Dittman
- Department of Biochemistry, Weill Cornell Medicine, New York, NY, United States.
| |
Collapse
|
6
|
Khvotchev M, Soloviev M. SNARE Modulators and SNARE Mimetic Peptides. Biomolecules 2022; 12:biom12121779. [PMID: 36551207 PMCID: PMC9776023 DOI: 10.3390/biom12121779] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2022] [Revised: 11/22/2022] [Accepted: 11/26/2022] [Indexed: 12/03/2022] Open
Abstract
The soluble N-ethylmaleimide-sensitive factor (NSF) attachment protein (SNAP) receptor (SNARE) proteins play a central role in most forms of intracellular membrane trafficking, a key process that allows for membrane and biocargo shuffling between multiple compartments within the cell and extracellular environment. The structural organization of SNARE proteins is relatively simple, with several intrinsically disordered and folded elements (e.g., SNARE motif, N-terminal domain, transmembrane region) that interact with other SNAREs, SNARE-regulating proteins and biological membranes. In this review, we discuss recent advances in the development of functional peptides that can modify SNARE-binding interfaces and modulate SNARE function. The ability of the relatively short SNARE motif to assemble spontaneously into stable coiled coil tetrahelical bundles has inspired the development of reduced SNARE-mimetic systems that use peptides for biological membrane fusion and for making large supramolecular protein complexes. We evaluate two such systems, based on peptide-nucleic acids (PNAs) and coiled coil peptides. We also review how the self-assembly of SNARE motifs can be exploited to drive on-demand assembly of complex re-engineered polypeptides.
Collapse
Affiliation(s)
- Mikhail Khvotchev
- Department of Biochemistry, Center for Neuroscience, Faculty of Science, Mahidol University, Bangkok 10400, Thailand
- Correspondence: (M.K.); (M.S.)
| | - Mikhail Soloviev
- Department of Biological Sciences, Royal Holloway University of London, Egham, Surrey TW20 0EX, UK
- Correspondence: (M.K.); (M.S.)
| |
Collapse
|
7
|
Liu J, Zhang C, Wang J, Huang Y, Shen D, Hu Y, Chu H, Yu X, Zhang L, Ma H. A Class I HDAC Inhibitor BG45 Alleviates Cognitive Impairment through the CaMKII/ITPKA/Ca 2+ Signaling Pathway. Pharmaceuticals (Basel) 2022; 15:1481. [PMID: 36558932 PMCID: PMC9786203 DOI: 10.3390/ph15121481] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2022] [Revised: 11/18/2022] [Accepted: 11/22/2022] [Indexed: 11/30/2022] Open
Abstract
Alzheimer's disease (AD) seriously endangers the health and life of elderly individuals worldwide. However, despite all scientific efforts, at the moment there are no effective clinical treatment options for AD. In this work, the effect of the class I histone deacetylase inhibitor (HDACI) BG45 on synapse-related proteins was investigated in primary neurons from APP/PS1 transgenic mice. The results showed that BG45 can upregulate the expression of synaptotagmin-1 (SYT-1) and neurofilament light chain (NF-L) in primary neurons. In vivo, the APPswe/PS1dE9 (APP/PS1) transgenic mice were treated with BG45 (30 mg/kg) daily for 12 days. Behavioral testing of BG45-treated APP/PS1 mice showed improvements in learning and memory. BG45 can alleviate damage to the dendritic spine and reduce the deposition of Aβ. Similar to the in vitro results, synapse-related proteins in the prefrontal cortex were increased after BG45 treatment. Proteomic analysis results highlighted the differences in the biological processes of energy metabolism and calmodulin regulation in APP/PS1 mice with or without BG45 treatment. Further verification demonstrated that the effect of BG45 on synapses and learning and memory may involve the CaMKII/ITPKA/Ca2+ pathway. These results suggest that class I HDACI BG45 might be a promising drug for the early clinical treatment of AD.
Collapse
Affiliation(s)
| | | | | | | | | | | | | | | | - Liyuan Zhang
- Department of Histology and Embryology, College of Basic Medical Sciences, Dalian Medical University, Dalian 116044, China
| | - Haiying Ma
- Department of Histology and Embryology, College of Basic Medical Sciences, Dalian Medical University, Dalian 116044, China
| |
Collapse
|
8
|
Kusick GF, Ogunmowo TH, Watanabe S. Transient docking of synaptic vesicles: Implications and mechanisms. Curr Opin Neurobiol 2022; 74:102535. [PMID: 35398664 PMCID: PMC9167714 DOI: 10.1016/j.conb.2022.102535] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2022] [Revised: 02/19/2022] [Accepted: 03/06/2022] [Indexed: 02/03/2023]
Abstract
As synaptic vesicles fuse, they must continually be replaced with new docked, fusion-competent vesicles to sustain neurotransmission. It has long been appreciated that vesicles are recruited to docking sites in an activity-dependent manner. However, once entering the sites, vesicles were thought to be stably docked, awaiting calcium signals. Based on recent data from electrophysiology, electron microscopy, biochemistry, and computer simulations, a picture emerges in which vesicles can rapidly and reversibly transit between docking and undocking during activity. This "transient docking" can account for many aspects of synaptic physiology. In this review, we cover recent evidence for transient docking, physiological processes at the synapse that it may support, and progress on the underlying mechanisms. We also discuss an open question: what determines for how long and whether vesicles stay docked, or eventually undock?
Collapse
Affiliation(s)
- Grant F Kusick
- Department of Cell Biology, Johns Hopkins University, School of Medicine, 725 N Wolfe St., Baltimore, MD 21287, USA; Biochemistry, Cellular and Molecular Biology Graduate Program, Johns Hopkins University, School of Medicine, 1830 E. Monument St., Baltimore, MD 21287, USA. https://twitter.com/@ultrafastgrant
| | - Tyler H Ogunmowo
- Department of Cell Biology, Johns Hopkins University, School of Medicine, 725 N Wolfe St., Baltimore, MD 21287, USA; Biochemistry, Cellular and Molecular Biology Graduate Program, Johns Hopkins University, School of Medicine, 1830 E. Monument St., Baltimore, MD 21287, USA. https://twitter.com/@unculturedTy
| | - Shigeki Watanabe
- Department of Cell Biology, Johns Hopkins University, School of Medicine, 725 N Wolfe St., Baltimore, MD 21287, USA; Solomon H. Snyder Department of Neuroscience, Johns Hopkins University, School of Medicine, 725 N Wolfe St., Baltimore, MD 21287, USA.
| |
Collapse
|
9
|
Energy matters: presynaptic metabolism and the maintenance of synaptic transmission. Nat Rev Neurosci 2021; 23:4-22. [PMID: 34782781 DOI: 10.1038/s41583-021-00535-8] [Citation(s) in RCA: 76] [Impact Index Per Article: 25.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/13/2021] [Indexed: 12/14/2022]
Abstract
Synaptic activity imposes large energy demands that are met by local adenosine triphosphate (ATP) synthesis through glycolysis and mitochondrial oxidative phosphorylation. ATP drives action potentials, supports synapse assembly and remodelling, and fuels synaptic vesicle filling and recycling, thus sustaining synaptic transmission. Given their polarized morphological features - including long axons and extensive branching in their terminal regions - neurons face exceptional challenges in maintaining presynaptic energy homeostasis, particularly during intensive synaptic activity. Recent studies have started to uncover the mechanisms and signalling pathways involved in activity-dependent and energy-sensitive regulation of presynaptic energetics, or 'synaptoenergetics'. These conceptual advances have established the energetic regulation of synaptic efficacy and plasticity as an exciting research field that is relevant to a range of neurological disorders associated with bioenergetic failure and synaptic dysfunction.
Collapse
|
10
|
Wang H, Huang W, Wang Y, Li W, Liu Q, Yin B, Liang L, Wang D, Guan X, Wang L. Enzyme Hinders HIV-1 Tat Viral Transport and Real-Time Measured with Nanopores. ACS Sens 2021; 6:3781-3788. [PMID: 34528798 DOI: 10.1021/acssensors.1c01717] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
HIV-1 Tat protein, an intercellular transporter with a determinant function of delivering "information-rich" molecules in viral multiplication, was tryptic-hydrolyzed and real-time single molecule-monitored in a transmembrane pore. The electrokinetic studies revealed the catalytic and inhibitory effects on enzymatic digestion associated with Ca2+ and Cu2+ ions, respectively, in response to binding interactions with trypsin. Our strategy permits accurate and distinguishable sensing of Ca2+ and Cu2+ via an enzyme assay. In addition, considering the closer mimic of the real situation of HIV spread, measurements in the serum and on cells were also investigated. Transmembrane current measurements together with fluorescence microscopy imaging indicated the potential to perturb the Tat transport in the serum environment and on cells. Because the involved Tat proteolysis should prevent the occurrence of viral delivery, the presented method probably enables efficient hindrance to HIV-1 infection, in complementary to current traditional treatments.
Collapse
Affiliation(s)
- Han Wang
- Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences, Chongqing 400714, China
- Chongqing School, University of Chinese Academy of Sciences, Chongqing 400714, China
- Chongqing Key Laboratory of Intelligent Medicine Engineering for Hepatopancreatobiliary Diseases, Chongqing 401147, China
| | - Wenli Huang
- Biotechnology and Nuclear Technology Research Institute, Sichuan Academy of Agricultural Sciences, Chengdu 610066, China
| | - Yunjiao Wang
- Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences, Chongqing 400714, China
- Chongqing School, University of Chinese Academy of Sciences, Chongqing 400714, China
| | - Wei Li
- Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences, Chongqing 400714, China
- Chongqing School, University of Chinese Academy of Sciences, Chongqing 400714, China
| | - Qianshan Liu
- Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences, Chongqing 400714, China
- Chongqing School, University of Chinese Academy of Sciences, Chongqing 400714, China
| | - Bohua Yin
- Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences, Chongqing 400714, China
| | - Liyuan Liang
- Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences, Chongqing 400714, China
- Chongqing School, University of Chinese Academy of Sciences, Chongqing 400714, China
| | - Deqiang Wang
- Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences, Chongqing 400714, China
- Chongqing School, University of Chinese Academy of Sciences, Chongqing 400714, China
| | - Xiyun Guan
- Department of Chemistry, Illinois Institute of Technology, Chicago, Illinois 60616, United States
| | - Liang Wang
- Chongqing Institute of Green and Intelligent Technology, Chinese Academy of Sciences, Chongqing 400714, China
- Chongqing School, University of Chinese Academy of Sciences, Chongqing 400714, China
- Chongqing Key Laboratory of Intelligent Medicine Engineering for Hepatopancreatobiliary Diseases, Chongqing 401147, China
| |
Collapse
|
11
|
Reva M, DiGregorio DA, Grebenkov DS. A first-passage approach to diffusion-influenced reversible binding and its insights into nanoscale signaling at the presynapse. Sci Rep 2021; 11:5377. [PMID: 33686123 PMCID: PMC7940439 DOI: 10.1038/s41598-021-84340-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2020] [Accepted: 01/04/2021] [Indexed: 11/21/2022] Open
Abstract
Synaptic transmission between neurons is governed by a cascade of stochastic calcium ion reaction–diffusion events within nerve terminals leading to vesicular release of neurotransmitter. Since experimental measurements of such systems are challenging due to their nanometer and sub-millisecond scale, numerical simulations remain the principal tool for studying calcium-dependent neurotransmitter release driven by electrical impulses, despite the limitations of time-consuming calculations. In this paper, we develop an analytical solution to rapidly explore dynamical stochastic reaction–diffusion problems based on first-passage times. This is the first analytical model that accounts simultaneously for relevant statistical features of calcium ion diffusion, buffering, and its binding/unbinding reaction with a calcium sensor for synaptic vesicle fusion. In particular, unbinding kinetics are shown to have a major impact on submillisecond sensor occupancy probability and therefore cannot be neglected. Using Monte Carlo simulations we validated our analytical solution for instantaneous calcium influx and that through voltage-gated calcium channels. We present a fast and rigorous analytical tool that permits a systematic exploration of the influence of various biophysical parameters on molecular interactions within cells, and which can serve as a building block for more general cell signaling simulators.
Collapse
Affiliation(s)
- Maria Reva
- Unit of Synapse and Circuit Dynamics, CNRS UMR 3571, Institut Pasteur, Paris, France.,ED3C, Sorbonne University, Paris, France
| | - David A DiGregorio
- Unit of Synapse and Circuit Dynamics, CNRS UMR 3571, Institut Pasteur, Paris, France.
| | - Denis S Grebenkov
- Laboratoire de Physique de la Matière Condensée (UMR 7643), CNRS - Ecole Polytechnique, IP Paris, 91128, Palaiseau, France.
| |
Collapse
|
12
|
Bowers MR, Reist NE. Synaptotagmin: Mechanisms of an electrostatic switch. Neurosci Lett 2020; 722:134834. [DOI: 10.1016/j.neulet.2020.134834] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2020] [Revised: 02/06/2020] [Accepted: 02/09/2020] [Indexed: 02/09/2023]
|
13
|
Courtney NA, Bao H, Briguglio JS, Chapman ER. Synaptotagmin 1 clamps synaptic vesicle fusion in mammalian neurons independent of complexin. Nat Commun 2019; 10:4076. [PMID: 31501440 PMCID: PMC6733930 DOI: 10.1038/s41467-019-12015-w] [Citation(s) in RCA: 57] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2019] [Accepted: 08/12/2019] [Indexed: 02/01/2023] Open
Abstract
Synaptic vesicle (SV) exocytosis is mediated by SNARE proteins. Reconstituted SNAREs are constitutively active, so a major focus has been to identify fusion clamps that regulate their activity in synapses: the primary candidates are synaptotagmin (syt) 1 and complexin I/II. Syt1 is a Ca2+ sensor for SV release that binds Ca2+ via tandem C2-domains, C2A and C2B. Here, we first determined whether these C2-domains execute distinct functions. Remarkably, the C2B domain profoundly clamped all forms of SV fusion, despite synchronizing residual evoked release and rescuing the readily-releasable pool. Release was strongly enhanced by an adjacent C2A domain, and by the concurrent binding of complexin to trans-SNARE complexes. Knockdown of complexin had no impact on C2B-mediated clamping of fusion. We postulate that the C2B domain of syt1, independent of complexin, is the molecular clamp that arrests SVs prior to Ca2+-triggered fusion.
Collapse
Affiliation(s)
- Nicholas A Courtney
- Department of Neuroscience and Howard Hughes Medical Institute, University of Wisconsin-Madison, 1111 Highland Ave., Madison, WI, 53705, USA
| | - Huan Bao
- Department of Neuroscience and Howard Hughes Medical Institute, University of Wisconsin-Madison, 1111 Highland Ave., Madison, WI, 53705, USA
| | - Joseph S Briguglio
- Department of Neuroscience and Howard Hughes Medical Institute, University of Wisconsin-Madison, 1111 Highland Ave., Madison, WI, 53705, USA
| | - Edwin R Chapman
- Department of Neuroscience and Howard Hughes Medical Institute, University of Wisconsin-Madison, 1111 Highland Ave., Madison, WI, 53705, USA.
| |
Collapse
|
14
|
Gangliosides interact with synaptotagmin to form the high-affinity receptor complex for botulinum neurotoxin B. Proc Natl Acad Sci U S A 2019; 116:18098-18108. [PMID: 31431523 DOI: 10.1073/pnas.1908051116] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Botulinum neurotoxin type B (BoNT/B) recognizes nerve terminals by binding to 2 receptor components: a polysialoganglioside, predominantly GT1b, and synaptotagmin 1/2. It is widely thought that BoNT/B initially binds to GT1b then diffuses in the plane of the membrane to interact with synaptotagmin. We have addressed the hypothesis that a GT1b-synaptotagmin cis complex forms the BoNT/B receptor. We identified a consensus glycosphingolipid-binding motif in the extracellular juxtamembrane domain of synaptotagmins 1/2 and confirmed by Langmuir monolayer, surface plasmon resonance, and circular dichroism that GT1b interacts with synaptotagmin peptides containing this sequence, inducing α-helical structure. Molecular modeling and tryptophan fluorescence spectroscopy were consistent with the intertwining of GT1b and synaptotagmin, involving cis interactions between the oligosaccharide and ceramide moieties of GT1b and the juxtamembrane and transmembrane domains of synaptotagmin, respectively. Furthermore, a point mutation on synaptotagmin, located outside of the BoNT/B-binding segment, inhibited GT1b binding and blocked GT1b-induced potentiation of BoNT/B binding to synaptotagmin-expressing cells. Our findings are consistent with a model in which a preassembled GT1b-synaptotagmin complex constitutes the high-affinity BoNT/B receptor.
Collapse
|
15
|
Grushin K, Wang J, Coleman J, Rothman JE, Sindelar CV, Krishnakumar SS. Structural basis for the clamping and Ca 2+ activation of SNARE-mediated fusion by synaptotagmin. Nat Commun 2019; 10:2413. [PMID: 31160571 PMCID: PMC6546687 DOI: 10.1038/s41467-019-10391-x] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2018] [Accepted: 05/08/2019] [Indexed: 12/22/2022] Open
Abstract
Synapotagmin-1 (Syt1) interacts with both SNARE proteins and lipid membranes to synchronize neurotransmitter release to calcium (Ca2+) influx. Here we report the cryo-electron microscopy structure of the Syt1-SNARE complex on anionic-lipid containing membranes. Under resting conditions, the Syt1 C2 domains bind the membrane with a magnesium (Mg2+)-mediated partial insertion of the aliphatic loops, alongside weak interactions with the anionic lipid headgroups. The C2B domain concurrently interacts the SNARE bundle via the 'primary' interface and is positioned between the SNAREpins and the membrane. In this configuration, Syt1 is projected to sterically delay the complete assembly of the associated SNAREpins and thus, contribute to clamping fusion. This Syt1-SNARE organization is disrupted upon Ca2+-influx as Syt1 reorients into the membrane, likely displacing the attached SNAREpins and reversing the fusion clamp. We thus conclude that the cation (Mg2+/Ca2+) dependent membrane interaction is a key determinant of the dual clamp/activator function of Synaptotagmin-1.
Collapse
Affiliation(s)
- Kirill Grushin
- Department of Cell Biology, Yale University School of Medicine, 333 Cedar Street, New Haven, CT, 06520, USA
| | - Jing Wang
- Department of Cell Biology, Yale University School of Medicine, 333 Cedar Street, New Haven, CT, 06520, USA
| | - Jeff Coleman
- Department of Cell Biology, Yale University School of Medicine, 333 Cedar Street, New Haven, CT, 06520, USA
| | - James E Rothman
- Department of Cell Biology, Yale University School of Medicine, 333 Cedar Street, New Haven, CT, 06520, USA
| | - Charles V Sindelar
- Department of Molecular Biophysics and Biochemistry, Yale University School of Medicine, 333 Cedar Street, New Haven, CT, 06520, USA.
| | - Shyam S Krishnakumar
- Department of Cell Biology, Yale University School of Medicine, 333 Cedar Street, New Haven, CT, 06520, USA.
- Department of Clinical and Experimental Epilepsy, Institute of Neurology, University College London, Queens Square House, London, WC1 3BG, UK.
| |
Collapse
|
16
|
Unc13: a multifunctional synaptic marvel. Curr Opin Neurobiol 2019; 57:17-25. [PMID: 30690332 DOI: 10.1016/j.conb.2018.12.011] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2018] [Revised: 12/18/2018] [Accepted: 12/19/2018] [Indexed: 12/16/2022]
Abstract
Nervous systems are built on synaptic connections, and our understanding of these complex compartments has deepened over the past quarter century as the diverse fields of genetics, molecular biology, physiology, and biochemistry each made significant in-roads into synaptic function. On the presynaptic side, an evolutionarily conserved core fusion apparatus constructed from a handful of proteins has emerged, with Unc13 serving as a hub that coordinates nearly every aspect of synaptic transmission. This review briefly highlights recent studies on diverse aspects of Unc13 function including roles in SNARE assembly and quality control, release site building, calcium channel proximity, and short-term synaptic plasticity.
Collapse
|
17
|
Suzuki A, Iwata J. Molecular Regulatory Mechanism of Exocytosis in the Salivary Glands. Int J Mol Sci 2018; 19:E3208. [PMID: 30336591 PMCID: PMC6214078 DOI: 10.3390/ijms19103208] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2018] [Revised: 10/10/2018] [Accepted: 10/11/2018] [Indexed: 12/12/2022] Open
Abstract
Every day, salivary glands produce about 0.5 to 1.5 L of saliva, which contains salivary proteins that are essential for oral health. The contents of saliva, 0.3% proteins (1.5 to 4.5 g) in fluid, help prevent oral infections, provide lubrication, aid digestion, and maintain oral health. Acinar cells in the lobular salivary glands secrete prepackaged secretory granules that contain salivary components such as amylase, mucins, and immunoglobulins. Despite the important physiological functions of salivary proteins, we know very little about the regulatory mechanisms of their secretion via exocytosis, which is a process essential for the secretion of functional proteins, not only in salivary glands, but also in other secretory organs, including lacrimal and mammary glands, the pancreas, and prostate. In this review, we discuss recent findings that elucidate exocytosis by exocrine glands, especially focusing on the salivary glands, in physiological and pathological conditions.
Collapse
Affiliation(s)
- Akiko Suzuki
- Department of Diagnostic & Biomedical Sciences, The University of Texas Health Science Center at Houston School of Dentistry, Houston, TX 77054, USA.
- Center for Craniofacial Research, The University of Texas Health Science Center at Houston School of Dentistry, Houston, TX 77054, USA.
| | - Junichi Iwata
- Department of Diagnostic & Biomedical Sciences, The University of Texas Health Science Center at Houston School of Dentistry, Houston, TX 77054, USA.
- Center for Craniofacial Research, The University of Texas Health Science Center at Houston School of Dentistry, Houston, TX 77054, USA.
- Program of Biochemistry and Cell Biology, The University of Texas Graduate School of Biomedical Sciences at Houston, Houston, TX 77030, USA.
| |
Collapse
|