Synaptotagmin Mutants Reveal Essential Functions for the C2B Domain in Ca2؉-Triggered Fusion and Recycling of Synaptic Vesicles in Vivo
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Antibodies to Snare Complex Proteins
ANTIBODIES TO SNARE COMPLEX PROTEINS Antibodies to SNARE Complex Proteins Synaptophysin VAMP/Synaptobrevin SNAP-25 Syntaxin CDCrel-1 Synaptotagmin-1 Munc18-1 Synapsin-1 INTERNATIONAL VERSION www.cedarlanelabs.com/SNARE CEDARLANE® is an ISO 9001 and ISO 13485 registered company Antibodies to SNARE Complex Proteins SNARE proteins are a large protein superfamily consisting of more than 60 members in yeast and mammals. The primary role of these proteins is to mediate fusion of vesicles with their target membrane-bound compartments (such as lysosomes). The most well studied SNARE proteins are those involved in mediating synaptic vesicle docking at the pre-synaptic membrane of neurons. During this process, syntaxin-1, SNAP-25 and munc18-1 associate and form a complex at the pre-synaptic membrane. This complex interacts with synaptobrevin-2 and synaptotagmin-1 located in synaptic vesicles and initiates docking, priming and fusion at the membrane. This fusion event leads to release of the vesicle's cargo into the synaptic cleft, where it can ultimately interact with the post-synaptic neuron. Antibodies to: Synaptophysin Synaptophysin is a 38 KDa synaptic vesicle (SV) glycoprotein containing four transmembrane domains. It is present in SVs of the neuroendocrine system, brain, spinal cord, retina, adrenal medulla and at neuromuscular junctions. Synaptophysin acts as a marker for neuroendocrine tumours and has been used to study the distribution of synapses within the brain due to its ubiquity at these regions. Although the exact function of synaptophysin is still unknown, several lines of evidence suggest it may have many important roles in SV exo and endocytosis. These include regulation of SNARE assembly, fusion pore formation initiating neurotransmitter release, and activation of SV endocytosis. -
SNARE Proteins and the Timing of Neurotransmitter Release
Molecular Psychiatry (1998) 3, 293–297 1998 Stockton Press All rights reserved 1359–4184/98 $12.00 NEWS & VIEWS SNARE proteins and the timing of neurotransmitter release The SNARE complex proteins have been implicated in exocytotic neurotransmitter release and other forms of membrane fusion. Recent work shows that NSF, the ATPase of the SNARE complex, regulates the kinetics of neurotransmitter release and can thereby control the inte- grative properties of synapses. Time is one of the most critical parameters in the func- hydrolyzes ATP. Because SNAREs are found on both tioning of the brain. Information transfer on the time- the synaptic vesicle membrane and the plasma mem- scale of milliseconds (10−3 seconds) is typical through- brane, it has been postulated that the various SNARE out the brain and in certain brain regions, such as the complexes mediate the interaction between the two auditory brainstem, time differences on the order of membranes before fusion and thus may be necessary microseconds (10−6 seconds) are used to define the fre- for neurotransmitter release.2 quency and location of perceived sounds. Thus infor- Evidence for a role for SNARE proteins in neuro- mation processing not only depends on a fast underly- transmitter release has come from a variety of sources. ing process but also on the precise timing of synaptic The most compelling indication of the central impor- activity. Such high temporal fidelity must rely upon tance of the three membrane SNARE proteins is that very finely-regulated molecular mechanisms. However, these proteins are remarkably specific targets of tetanus until recently the identity of these mechanisms has and botulinum toxins, a group of potent neurotoxins been remarkably elusive. -
Defining the Kv2.1–Syntaxin Molecular Interaction Identifies a First-In-Class Small Molecule Neuroprotectant
Defining the Kv2.1–syntaxin molecular interaction identifies a first-in-class small molecule neuroprotectant Chung-Yang Yeha,b,1, Zhaofeng Yec,d,1, Aubin Moutale, Shivani Gaura,b, Amanda M. Hentonf,g, Stylianos Kouvarosf,g, Jami L. Salomana, Karen A. Hartnett-Scotta,b, Thanos Tzounopoulosa,f,g, Rajesh Khannae, Elias Aizenmana,b,g,2, and Carlos J. Camachoc,2 aDepartment of Neurobiology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261; bPittsburgh Institute for Neurodegenerative Diseases, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261; cDepartment of Computational and Systems Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261; dSchool of Medicine, Tsinghua University, Beijing 100871, China; eDepartment of Pharmacology, College of Medicine, University of Arizona, Tucson, AZ 85724; fDepartment of Otolaryngology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261; and gPittsburgh Hearing Research Center, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261 Edited by Lily Yeh Jan, University of California, San Francisco, CA, and approved June 19, 2019 (received for review February 27, 2019) + The neuronal cell death-promoting loss of cytoplasmic K follow- (13). The Kv2.1-dependent cell death pathway is normally initiated ing injury is mediated by an increase in Kv2.1 potassium channels in by the oxidative liberation of zinc from intracellular metal-binding the plasma membrane. This phenomenon relies on Kv2.1 binding to proteins (14), leading to the sequential phosphorylation of syntaxin 1A via 9 amino acids within the channel intrinsically disor- Kv2.1 residues Y124 and S800 by Src and p38 kinases, respectively dered C terminus. Preventing this interaction with a cell and blood- (15–17). -
Identification of Synaptic Proteins and Their Isoform Mrnas In
Proc. Natl. Acad. Sci. USA Vol. 91, pp. 12487-12491, December 1994 Cell Biology Identification of synaptic proteins and their isoform mRNAs in compartments of pancreatic endocrine cells (exocytosis/secretion/insulin/diabetes) GUNILLA JACOBSSON*, ANDREW J. BEANt, RICHARD H. SCHELLERt, LISA JUNTTI-BERGGRENt, JUDE T. DEENEYt, PER-OLOF BERGGRENt AND BJORN MEISTER*§ *Department of Neuroscience and tRolf Luft's Center for Diabetes Research, Department of Molecular Medicine, Karolinska Institute, S-171 77 Stockholm, Sweden; and tDepartment of Molecular and Cellular Physiology, Howard Hughes Medical Institute, Beckman Center, Stanford University, Stanford, CA 94305 Communicated by Tomas Hokfelt, August 30, 1994 ABSTRACT Several proteins that are of importance for clostridial neurotoxins, including tetanus toxin and botuli- membrane trafficking in the nerve terminal have recently been num neurotoxin B, whereas botulinum neurotoxins D and F characterized. We have used Western blot and immunohis- are capable of cleaving both forms of VAMP (10-12). tochemistry to show that synaptotagmin, synaptobrevin/VAMP VAMP-1 and VAMP-2 are encoded by two distinct genes (13) (vesicle-associated membrane protein), SNAP-25 (synaptosom- and are differentially expressed in the nervous system (14). al-associated protein of 25 kDa), and syntaxin proteins are Cellubrevin is a homologue of VAMP, which is present in a present in cells of the islets of Langerhans in the endocrine wide variety of tissues and may be a membrane trafficking pancreas. Synaptotagmin-like immunoreactivity (-LI) was lo- protein of a constitutively recycling pathway (15). calized to granules within the cytoplasm of a few endocrine cells In contrast to synaptotagmin and VAMP, the synaptoso- located in the periphery of the islets, identified as somatostatin- mal-associated protein of 25 kDa (SNAP-25) is located at the containing cells, and in many nerve fibers within the islets. -
Structural Insights Into Membrane Fusion Mediated by Convergent Small Fusogens
cells Review Structural Insights into Membrane Fusion Mediated by Convergent Small Fusogens Yiming Yang * and Nandini Nagarajan Margam Department of Microbiology and Immunology, Dalhousie University, Halifax, NS B3H 4R2, Canada; [email protected] * Correspondence: [email protected] Abstract: From lifeless viral particles to complex multicellular organisms, membrane fusion is inarguably the important fundamental biological phenomena. Sitting at the heart of membrane fusion are protein mediators known as fusogens. Despite the extensive functional and structural characterization of these proteins in recent years, scientists are still grappling with the fundamental mechanisms underlying membrane fusion. From an evolutionary perspective, fusogens follow divergent evolutionary principles in that they are functionally independent and do not share any sequence identity; however, they possess structural similarity, raising the possibility that membrane fusion is mediated by essential motifs ubiquitous to all. In this review, we particularly emphasize structural characteristics of small-molecular-weight fusogens in the hope of uncovering the most fundamental aspects mediating membrane–membrane interactions. By identifying and elucidating fusion-dependent functional domains, this review paves the way for future research exploring novel fusogens in health and disease. Keywords: fusogen; SNARE; FAST; atlastin; spanin; myomaker; myomerger; membrane fusion 1. Introduction Citation: Yang, Y.; Margam, N.N. Structural Insights into Membrane Membrane fusion -
Mechanisms of Synaptic Plasticity Mediated by Clathrin Adaptor-Protein Complexes 1 and 2 in Mice
Mechanisms of synaptic plasticity mediated by Clathrin Adaptor-protein complexes 1 and 2 in mice Dissertation for the award of the degree “Doctor rerum naturalium” at the Georg-August-University Göttingen within the doctoral program “Molecular Biology of Cells” of the Georg-August University School of Science (GAUSS) Submitted by Ratnakar Mishra Born in Birpur, Bihar, India Göttingen, Germany 2019 1 Members of the Thesis Committee Prof. Dr. Peter Schu Institute for Cellular Biochemistry, (Supervisor and first referee) University Medical Center Göttingen, Germany Dr. Hans Dieter Schmitt Neurobiology, Max Planck Institute (Second referee) for Biophysical Chemistry, Göttingen, Germany Prof. Dr. med. Thomas A. Bayer Division of Molecular Psychiatry, University Medical Center, Göttingen, Germany Additional Members of the Examination Board Prof. Dr. Silvio O. Rizzoli Department of Neuro-and Sensory Physiology, University Medical Center Göttingen, Germany Dr. Roland Dosch Institute of Developmental Biochemistry, University Medical Center Göttingen, Germany Prof. Dr. med. Martin Oppermann Institute of Cellular and Molecular Immunology, University Medical Center, Göttingen, Germany Date of oral examination: 14th may 2019 2 Table of Contents List of abbreviations ................................................................................. 5 Abstract ................................................................................................... 7 Chapter 1: Introduction ............................................................................ -
SNAP-24, a Novel Drosophila SNARE Protein 4057 Proteins Were Purified on Glutathione Beads and Cleaved from the GST Fig
Journal of Cell Science 113, 4055-4064 (2000) 4055 Printed in Great Britain © The Company of Biologists Limited 2000 JCS1894 SNAP-24, a Drosophila SNAP-25 homologue on granule membranes, is a putative mediator of secretion and granule-granule fusion in salivary glands Barbara A. Niemeyer*,‡ and Thomas L. Schwarz§ Department of Molecular and Cellular Physiology, Stanford Medical School, Stanford, CA 94305, USA *Present address: Department of Pharmacology and Toxicology, School of Medicine, University of Saarland, D-66421 Homburg, Germany ‡Author for correspondence (e-mail: [email protected]) §Present address: Harvard Medical School, Division of Neuroscience, The Children’s Hospital, 300 Longwood Avenue, Boston, MA 02115, USA Accepted 16 September; published on WWW 31 October 2000 SUMMARY Fusion of vesicles with target membranes is dependent is not concentrated in synaptic regions. In vitro studies, on the interaction of target (t) and vesicle (v) SNARE however, show that SNAP-24 can form core complexes with (soluble NSF (N-ethylmaleimide-sensitive fusion protein) syntaxin and both synaptic and non-synaptic v-SNAREs. attachment protein receptor) proteins located on opposing High levels of SNAP-24 are found in larval salivary glands, membranes. For fusion at the plasma membrane, the t- where SNAP-24 localizes mainly to granule membranes SNARE SNAP-25 is essential. In Drosophila, the only rather than the plasma membrane. During glue secretion, known SNAP-25 isoform is specific to neuronal axons and the massive exocytotic event of these glands, SNAP-24 synapses and additional t-SNAREs must exist that mediate containing granules fuse with one another and the apical both non-synaptic fusion in neurons and constitutive and membrane, suggesting that glue secretion utilizes regulated fusion in other cells. -
Is Synaptotagmin the Calcium Sensor? Motojiro Yoshihara, Bill Adolfsen and J Troy Littleton
315 Is synaptotagmin the calcium sensor? Motojiro Yoshihara, Bill Adolfsen and J Troy Littletonà After much debate, recent progress indicates that the synaptic synaptotagmins, which are transmembrane proteins con- vesicle protein synaptotagmin I probably functions as the taining tandem calcium-binding C2 domains (C2A and calcium sensor for synchronous neurotransmitter release. C2B) (Figure 1a). Synaptotagmin I is an abundant cal- Following calcium influx into presynaptic terminals, cium-binding synaptic vesicle protein [8,9] that has been synaptotagmin I rapidly triggers the fusion of synaptic vesicles demonstrated via genetic studies to be important for with the plasma membrane and underlies the fourth-order efficient synaptic transmission in vivo [10–13]. The C2 calcium cooperativity of release. Biochemical and genetic domains of synaptotagmin I bind negatively-charged studies suggest that lipid and SNARE interactions underlie phospholipids in a calcium-dependent manner [9,14,15, synaptotagmin’s ability to mediate the incredible speed of 16–18]. There is compelling evidence that phospholipid vesicle fusion that is the hallmark of fast synaptic transmission. binding is an effector interaction in vesicle fusion, as the calcium dependence of this process ( 74 mM) and its Addresses rapid kinetics (on a millisecond scale) (Figure 1b) fit Picower Center for Learning and Memory, Department of Biology and reasonably well with the predicted requirements of Department of Brain and Cognitive Sciences, Massachusetts synaptic transmission [15]. In addition to phospholipid Institute of Technology, Cambridge, MA 02139, USA Ãe-mail: [email protected] binding, the calcium-stimulated interaction between synaptotagmin and the t-SNAREs syntaxin and SNAP- 25 [15,19–23] provides a direct link between calcium and Current Opinion in Neurobiology 2003, 13:315–323 the fusion complex. -
Regulation of Neuronal Communication by G Protein-Coupled Receptors ⇑ Yunhong Huang, Amantha Thathiah
View metadata, citation and similar papers at core.ac.uk brought to you by CORE provided by Elsevier - Publisher Connector FEBS Letters 589 (2015) 1607–1619 journal homepage: www.FEBSLetters.org Review Regulation of neuronal communication by G protein-coupled receptors ⇑ Yunhong Huang, Amantha Thathiah VIB Center for the Biology of Disease, Leuven, Belgium Center for Human Genetics (CME) and Leuven Institute for Neurodegenerative Diseases (LIND), University of Leuven (KUL), Leuven, Belgium article info abstract Article history: Neuronal communication plays an essential role in the propagation of information in the brain and Received 31 March 2015 requires a precisely orchestrated connectivity between neurons. Synaptic transmission is the mech- Revised 5 May 2015 anism through which neurons communicate with each other. It is a strictly regulated process which Accepted 5 May 2015 involves membrane depolarization, the cellular exocytosis machinery, neurotransmitter release Available online 14 May 2015 from synaptic vesicles into the synaptic cleft, and the interaction between ion channels, G Edited by Wilhelm Just protein-coupled receptors (GPCRs), and downstream effector molecules. The focus of this review is to explore the role of GPCRs and G protein-signaling in neurotransmission, to highlight the func- tion of GPCRs, which are localized in both presynaptic and postsynaptic membrane terminals, in reg- Keywords: G protein-coupled receptors ulation of intrasynaptic and intersynaptic communication, and to discuss the involvement of G-proteins astrocytic GPCRs in the regulation of neuronal communication. Neuronal communication Ó 2015 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved. Synaptic transmission Signaling Astrocytes Neurons Autoreceptors Neurotransmitters 1. -
Sorting Nexin-21 Is a Scaffold for the Endosomal Recruitment of Huntingtin
Danson, C. , Pearson, N., Heesom, K., & Cullen, P. (2018). Sorting nexin-21 is a scaffold for the endosomal recruitment of huntingtin. Journal of Cell Science. https://doi.org/10.1242/jcs.211672 Publisher's PDF, also known as Version of record Link to published version (if available): 10.1242/jcs.211672 Link to publication record in Explore Bristol Research PDF-document This is the final published version of the article (version of record). It first appeared online via Company of Biologists at http://jcs.biologists.org/content/131/17/jcs211672 . Please refer to any applicable terms of use of the publisher. University of Bristol - Explore Bristol Research General rights This document is made available in accordance with publisher policies. Please cite only the published version using the reference above. Full terms of use are available: http://www.bristol.ac.uk/red/research-policy/pure/user-guides/ebr-terms/ © 2018. Published by The Company of Biologists Ltd | Journal of Cell Science (2018) 131, jcs211672. doi:10.1242/jcs.211672 RESEARCH ARTICLE Sorting nexin-21 is a scaffold for the endosomal recruitment of huntingtin Chris M. Danson1, Neil Pearson1, Kate J. Heesom2 and Peter J. Cullen1,* ABSTRACT transport from the trans-Golgi network (TGN) (Maxfield and The endo-lysosomal network serves an essential role in determining McGraw, 2004; Johannes and Popoff, 2008; Grant and Donaldson, the fate of endocytosed transmembrane proteins and their associated 2009; Huotari and Helenius, 2011; Johannes and Wunder, 2011; proteins and lipids. Sorting nexins (SNXs) play a central role in the Hsu et al., 2012). These pathways converge at the sorting endosome, functional organisation of this network. -
The Role of ADP-Ribosylation Factor and SAR1 in Vesicular Trafficking in Plants
View metadata, citation and similar papers at core.ac.uk brought to you by CORE provided by Elsevier - Publisher Connector Biochimica et Biophysica Acta 1664 (2004) 9–30 www.bba-direct.com Review The role of ADP-ribosylation factor and SAR1 in vesicular trafficking in plants Abdul R. Memon* TU¨ BI˙TAK, Research Institute for Genetic Engineering and Biotechnology, P.O. Box 21, 41470 Gebze, Kocaeli, Turkey Received 8 July 2003; received in revised form 22 March 2004; accepted 19 April 2004 Available online 8 May 2004 Abstract Ras-like small GTP binding proteins regulate a wide variety of intracellular signalling and vesicular trafficking pathways in eukaryotic cells including plant cells. They share a common structure that operates as a molecular switch by cycling between active GTP-bound and inactive GDP-bound conformational states. The active GTP-bound state is regulated by guanine nucleotide exchange factors (GEF), which promote the exchange of GDP for GTP. The inactive GDP-bound state is promoted by GTPase-activating proteins (GAPs) which accelerate GTP hydrolysis by orders of magnitude. Two types of small GTP-binding proteins, ADP-ribosylation factor (Arf) and secretion-associated and Ras-related (Sar), are major regulators of vesicle biogenesis in intracellular traffic and are founding members of a growing family that also includes Arf-related proteins (Arp) and Arf-like (Arl) proteins. The most widely involved small GTPase in vesicular trafficking is probably Arf1, which not only controls assembly of COPI- and AP1, AP3, and AP4/clathrin-coated vesicles but also recruits other proteins to membranes, including some that may be components of further coats. -
Molecular Mechanism of Fusion Pore Formation Driven by the Neuronal SNARE Complex
Molecular mechanism of fusion pore formation driven by the neuronal SNARE complex Satyan Sharmaa,1 and Manfred Lindaua,b aLaboratory for Nanoscale Cell Biology, Max Planck Institute for Biophysical Chemistry, 37077 Göttingen, Germany and bSchool of Applied and Engineering Physics, Cornell University, Ithaca, NY 14850 Edited by Axel T. Brunger, Stanford University, Stanford, CA, and approved November 1, 2018 (received for review October 2, 2018) Release of neurotransmitters from synaptic vesicles begins with a systems in which various copy numbers of syb2 were incorporated narrow fusion pore, the structure of which remains unresolved. To in an ND while the t-SNAREs were present on a liposome have obtain a structural model of the fusion pore, we performed coarse- been used experimentally to study SNARE-mediated mem- grained molecular dynamics simulations of fusion between a brane fusion (13, 17). The small dimensions of the ND compared nanodisc and a planar bilayer bridged by four partially unzipped with a spherical vesicle makes such systems ideally suited for MD SNARE complexes. The simulations revealed that zipping of SNARE simulations without introducing extreme curvature, which is well complexes pulls the polar C-terminal residues of the synaptobrevin known to strongly influence the propensity of fusion (18–20). 2 and syntaxin 1A transmembrane domains to form a hydrophilic MARTINI-based CGMD simulations have been used in several – core between the two distal leaflets, inducing fusion pore forma- studies of membrane fusion (16, 21 23). To elucidate the fusion tion. The estimated conductances of these fusion pores are in good pore structure and the mechanism of its formation, we performed agreement with experimental values.