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Forrester MT, Egol JR, Tata A, Tata PR, Foster MW. Analysis of Protein Cysteine Acylation Using a Modified Suspension Trap (Acyl-Trap). BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.03.23.586403. [PMID: 38585928 PMCID: PMC10996552 DOI: 10.1101/2024.03.23.586403] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/09/2024]
Abstract
Protein cysteine thiols undergo reversible S-acylation via a thioester linkage in vivo. S-palmitoylation, modification by C16:0 fatty acid, is a common S-acylation that mediates protein-membrane and protein-protein interactions critical to an array of biological processes, from homeostatic lung surfactant function to cellular transformation. The most widely used S-acylation assays, including acyl-biotin exchange (ABE) and acyl resin-assisted capture (Acyl-RAC), utilize blocking of free Cys thiols, hydroxylamine-dependent cleavage of the thioester and subsequent labeling of nascent thiol. ABE and Acyl-RAC have enabled both the proteome-wide identification of S-palmitoylation sites and basic biochemical studies. Yet, these assays generally utilize hundreds of micrograms to milligrams of input material and require numerous reagent removal and washing steps, making them laborious and ill-suited for high throughput and low input applications. To overcome this, we devised "Acyl-Trap", a suspension trap-based assay that utilizes a thiol-reactive quartz to enable buffer exchange and hydroxylamine-mediated S-acyl enrichment from 20-50 micrograms of input protein. The method is compatible with protein-level detection of Sacylated proteins as well as S-acyl site-based identification and quantification using on-quartz isobaric (tandem mass tag) labeling and LC-MS/MS. Also described are conditions for long-term hydroxylamine storage, which further expedites the assay and minimizes waste. More generally, Acyl-Trap serves as a proof-of-concept for PTM-tailored suspension traps suitable for both traditional intact protein detection and chemoproteomic workflows.
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Affiliation(s)
- Michael T Forrester
- Division of Pulmonary, Allergy and Critical Care Medicine, Duke University School of Medicine, Durham, NC, 27710, USA
| | - Jacob R Egol
- Department of Cell Biology, Duke University School of Medicine, Durham, NC, 27710, USA
| | - Aleksandra Tata
- Department of Cell Biology, Duke University School of Medicine, Durham, NC, 27710, USA
| | - Purushothama Rao Tata
- Division of Pulmonary, Allergy and Critical Care Medicine, Duke University School of Medicine, Durham, NC, 27710, USA
- Department of Cell Biology, Duke University School of Medicine, Durham, NC, 27710, USA
- Duke Regeneration Center, Duke University School of Medicine, Durham, NC, 27710, USA
| | - Matthew W Foster
- Division of Pulmonary, Allergy and Critical Care Medicine, Duke University School of Medicine, Durham, NC, 27710, USA
- Proteomics and Metabolomics Core Facility, Duke University School of Medicine, Durham, NC, 27710, USA
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2
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He Q, Qu M, Shen T, Su J, Xu Y, Xu C, Barkat MQ, Cai J, Zhu H, Zeng LH, Wu X. Control of mitochondria-associated endoplasmic reticulum membranes by protein S-palmitoylation: Novel therapeutic targets for neurodegenerative diseases. Ageing Res Rev 2023; 87:101920. [PMID: 37004843 DOI: 10.1016/j.arr.2023.101920] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2022] [Revised: 03/30/2023] [Accepted: 03/30/2023] [Indexed: 04/03/2023]
Abstract
Mitochondria-associated endoplasmic reticulum membranes (MAMs) are dynamic coupling structures between mitochondria and the endoplasmic reticulum (ER). As a new subcellular structure, MAMs combine the two critical organelle functions. Mitochondria and the ER could regulate each other via MAMs. MAMs are involved in calcium (Ca2+) homeostasis, autophagy, ER stress, lipid metabolism, etc. Researchers have found that MAMs are closely related to metabolic syndrome and neurodegenerative diseases (NDs). The formation of MAMs and their functions depend on specific proteins. Numerous protein enrichments, such as the IP3R-Grp75-VDAC complex, constitute MAMs. The changes in these proteins govern the interaction between mitochondria and the ER; they also affect the biological functions of MAMs. S-palmitoylation is a reversible protein post-translational modification (PTM) that mainly occurs on protein cysteine residues. More and more studies have shown that the S-palmitoylation of proteins is closely related to their membrane localization. Here, we first briefly describe the composition and function of MAMs, reviewing the component and biological roles of MAMs mediated by S-palmitoylation, elaborating on S-palmitoylated proteins in Ca2+ flux, lipid rafts, and so on. We try to provide new insight into the molecular basis of MAMs-related diseases, mainly NDs. Finally, we propose potential drug compounds targeting S-palmitoylation.
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Affiliation(s)
- Qiangqiang He
- Department of Pharmacology, Zhejiang University School of Medicine, Hangzhou 310058, China; Department of Pharmacology, Hangzhou City University, Hangzhou 310015, China
| | - Meiyu Qu
- Department of Pharmacology, Zhejiang University School of Medicine, Hangzhou 310058, China
| | - Tingyu Shen
- Department of Pharmacology, Zhejiang University School of Medicine, Hangzhou 310058, China
| | - Jiakun Su
- Technology Center, China Tobacco Jiangxi Industrial Co. Ltd., Nanchang 330096, China
| | - Yana Xu
- Department of Pharmacology, Zhejiang University School of Medicine, Hangzhou 310058, China
| | - Chengyun Xu
- Department of Pharmacology, Zhejiang University School of Medicine, Hangzhou 310058, China
| | - Muhammad Qasim Barkat
- Department of Pharmacology, Zhejiang University School of Medicine, Hangzhou 310058, China
| | - Jibao Cai
- Technology Center, China Tobacco Jiangxi Industrial Co. Ltd., Nanchang 330096, China
| | - Haibin Zhu
- Department of Gynecology, the First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou 310003, China
| | - Ling-Hui Zeng
- Department of Pharmacology, Hangzhou City University, Hangzhou 310015, China.
| | - Ximei Wu
- Department of Pharmacology, Zhejiang University School of Medicine, Hangzhou 310058, China.
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Akefe IO, Osborne SL, Matthews B, Wallis TP, Meunier FA. Lipids and Secretory Vesicle Exocytosis. ADVANCES IN NEUROBIOLOGY 2023; 33:357-397. [PMID: 37615874 DOI: 10.1007/978-3-031-34229-5_14] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/25/2023]
Abstract
In recent years, the number of studies implicating lipids in the regulation of synaptic vesicle exocytosis has risen considerably. It has become increasingly clear that lipids such as phosphoinositides, lysophospholipids, cholesterol, arachidonic acid and myristic acid play critical regulatory roles in the processes leading up to exocytosis. Lipids may affect membrane fusion reactions by altering the physical properties of the membrane, recruiting key regulatory proteins, concentrating proteins into exocytic "hotspots" or by modulating protein functions allosterically. Discrete changes in phosphoinositides concentration are involved in multiple trafficking events including exocytosis and endocytosis. Lipid-modifying enzymes such as the DDHD2 isoform of phospholipase A1 were recently shown to contribute to memory acquisition via dynamic modifications of the brain lipid landscape. Considering the increasing reports on neurodegenerative disorders associated with aberrant intracellular trafficking, an improved understanding of the control of lipid pathways is physiologically and clinically significant and will afford unique insights into mechanisms and therapeutic methods for neurodegenerative diseases. Consequently, this chapter will discuss the different classes of lipids, phospholipase enzymes, the evidence linking them to synaptic neurotransmitter release and how they act to regulate key steps in the multi-step process leading to neuronal communication and memory acquisition.
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Affiliation(s)
- Isaac O Akefe
- Clem Jones Centre for Ageing Dementia Research, Queensland Brain Institute, The University of Queensland, St Lucia, QLD, Australia
| | - Shona L Osborne
- ARC Training Centre for Innovation in Biomedical Imaging Technology (CIBIT), The University of Queensland, St Lucia, QLD, Australia
| | - Benjamin Matthews
- Clem Jones Centre for Ageing Dementia Research, Queensland Brain Institute, The University of Queensland, St Lucia, QLD, Australia
| | - Tristan P Wallis
- Clem Jones Centre for Ageing Dementia Research, Queensland Brain Institute, The University of Queensland, St Lucia, QLD, Australia
| | - Frédéric A Meunier
- Clem Jones Centre for Ageing Dementia Research, Queensland Brain Institute, The University of Queensland, St Lucia, QLD, Australia.
- School of Biomedical Sciences, The University of Queensland, St Lucia, QLD, Australia.
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4
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Hwang J, Thurmond DC. Exocytosis Proteins: Typical and Atypical Mechanisms of Action in Skeletal Muscle. Front Endocrinol (Lausanne) 2022; 13:915509. [PMID: 35774142 PMCID: PMC9238359 DOI: 10.3389/fendo.2022.915509] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/08/2022] [Accepted: 05/11/2022] [Indexed: 11/18/2022] Open
Abstract
Insulin-stimulated glucose uptake in skeletal muscle is of fundamental importance to prevent postprandial hyperglycemia, and long-term deficits in insulin-stimulated glucose uptake underlie insulin resistance and type 2 diabetes. Skeletal muscle is responsible for ~80% of the peripheral glucose uptake from circulation via the insulin-responsive glucose transporter GLUT4. GLUT4 is mainly sequestered in intracellular GLUT4 storage vesicles in the basal state. In response to insulin, the GLUT4 storage vesicles rapidly translocate to the plasma membrane, where they undergo vesicle docking, priming, and fusion via the high-affinity interactions among the soluble N-ethylmaleimide sensitive factor attachment protein receptor (SNARE) exocytosis proteins and their regulators. Numerous studies have elucidated that GLUT4 translocation is defective in insulin resistance and type 2 diabetes. Emerging evidence also links defects in several SNAREs and SNARE regulatory proteins to insulin resistance and type 2 diabetes in rodents and humans. Therefore, we highlight the latest research on the role of SNAREs and their regulatory proteins in insulin-stimulated GLUT4 translocation in skeletal muscle. Subsequently, we discuss the novel emerging role of SNARE proteins as interaction partners in pathways not typically thought to involve SNAREs and how these atypical functions reveal novel therapeutic targets for combating peripheral insulin resistance and diabetes.
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Affiliation(s)
| | - Debbie C. Thurmond
- Department of Molecular and Cellular Endocrinology, Arthur Riggs Diabetes and Metabolism Research Institute, Beckman Research Institute at City of Hope, Duarte, CA, United States
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Theater in the Self-Cleaning Cell: Intrinsically Disordered Proteins or Protein Regions Acting with Membranes in Autophagy. MEMBRANES 2022; 12:membranes12050457. [PMID: 35629783 PMCID: PMC9143426 DOI: 10.3390/membranes12050457] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/28/2022] [Revised: 04/19/2022] [Accepted: 04/22/2022] [Indexed: 12/30/2022]
Abstract
Intrinsically disordered proteins and protein regions (IDPs/IDPRs) are mainly involved in signaling pathways, where fast regulation, temporal interactions, promiscuous interactions, and assemblies of structurally diverse components including membranes are essential. The autophagy pathway builds, de novo, a membrane organelle, the autophagosome, using carefully orchestrated interactions between proteins and lipid bilayers. Here, we discuss molecular mechanisms related to the protein disorder-based interactions of the autophagy machinery with membranes. We describe not only membrane binding phenomenon, but also examples of membrane remodeling processes including membrane tethering, bending, curvature sensing, and/or fragmentation of membrane organelles such as the endoplasmic reticulum, which is an important membrane source as well as cargo for autophagy. Summary of the current state of knowledge presented here will hopefully inspire new studies. A profound understanding of the autophagic protein–membrane interface is essential for advancements in therapeutic interventions against major human diseases, in which autophagy is involved including neurodegeneration, cancer as well as cardiovascular, metabolic, infectious, musculoskeletal, and other disorders.
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Cali E, Rocca C, Salpietro V, Houlden H. Epileptic Phenotypes Associated With SNAREs and Related Synaptic Vesicle Exocytosis Machinery. Front Neurol 2022; 12:806506. [PMID: 35095745 PMCID: PMC8792400 DOI: 10.3389/fneur.2021.806506] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2021] [Accepted: 11/16/2021] [Indexed: 01/29/2023] Open
Abstract
SNAREs (soluble N-ethylmaleimide sensitive factor attachment protein receptor) are an heterogeneous family of proteins that, together with their key regulators, are implicated in synaptic vesicle exocytosis and synaptic transmission. SNAREs represent the core component of this protein complex. Although the specific mechanisms of the SNARE machinery is still not completely uncovered, studies in recent years have provided a clearer understanding of the interactions regulating the essential fusion machinery for neurotransmitter release. Mutations in genes encoding SNARE proteins or SNARE complex associated proteins have been associated with a variable spectrum of neurological conditions that have been recently defined as “SNAREopathies.” These include neurodevelopmental disorder, autism spectrum disorder (ASD), movement disorders, seizures and epileptiform abnormalities. The SNARE phenotypic spectrum associated with seizures ranges from simple febrile seizures and infantile spasms, to severe early-onset epileptic encephalopathies. Our study aims to review and delineate the epileptic phenotypes associated with dysregulation of synaptic vesicle exocytosis and transmission, focusing on the main proteins of the SNARE core complex (STX1B, VAMP2, SNAP25), tethering complex (STXBP1), and related downstream regulators.
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Affiliation(s)
- Elisa Cali
- MRC Centre for Neuromuscular Diseases, UCL Queen Square Institute of Neurology, London, United Kingdom
| | - Clarissa Rocca
- MRC Centre for Neuromuscular Diseases, UCL Queen Square Institute of Neurology, London, United Kingdom
| | - Vincenzo Salpietro
- MRC Centre for Neuromuscular Diseases, UCL Queen Square Institute of Neurology, London, United Kingdom
| | - Henry Houlden
- MRC Centre for Neuromuscular Diseases, UCL Queen Square Institute of Neurology, London, United Kingdom
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Villanueva J, Gimenez-Molina Y, Davletov B, Gutiérrez LM. Vesicle Fusion as a Target Process for the Action of Sphingosine and Its Derived Drugs. Int J Mol Sci 2022; 23:ijms23031086. [PMID: 35163009 PMCID: PMC8834808 DOI: 10.3390/ijms23031086] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2021] [Revised: 01/13/2022] [Accepted: 01/18/2022] [Indexed: 11/16/2022] Open
Abstract
The fusion of membranes is a central part of the physiological processes involving the intracellular transport and maturation of vesicles and the final release of their contents, such as neurotransmitters and hormones, by exocytosis. Traditionally, in this process, proteins, such SNAREs have been considered the essential components of the fusion molecular machinery, while lipids have been seen as merely structural elements. Nevertheless, sphingosine, an intracellular signalling lipid, greatly increases the release of neurotransmitters in neuronal and neuroendocrine cells, affecting the exocytotic fusion mode through the direct interaction with SNAREs. Moreover, recent studies suggest that FTY-720 (Fingolimod), a sphingosine structural analogue used in the treatment of multiple sclerosis, simulates sphingosine in the promotion of exocytosis. Furthermore, this drug also induces the intracellular fusion of organelles such as dense vesicles and mitochondria causing cell death in neuroendocrine cells. Therefore, the effect of sphingosine and synthetic derivatives on the heterologous and homologous fusion of organelles can be considered as a new mechanism of action of sphingolipids influencing important physiological processes, which could underlie therapeutic uses of sphingosine derived lipids in the treatment of neurodegenerative disorders and cancers of neuronal origin such neuroblastoma.
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Affiliation(s)
- José Villanueva
- Instituto de Neurociencias, CSIC-Universidad Miguel Hernández, Cra de Valencia S/N, Sant Joan d’Alacant, 03550 Alicante, Spain;
- Correspondence: (J.V.); (L.M.G.)
| | - Yolanda Gimenez-Molina
- Instituto de Neurociencias, CSIC-Universidad Miguel Hernández, Cra de Valencia S/N, Sant Joan d’Alacant, 03550 Alicante, Spain;
| | - Bazbek Davletov
- Department of Biomedical Science, University of Sheffield, Sheffield S10 2TN, UK;
| | - Luis M. Gutiérrez
- Instituto de Neurociencias, CSIC-Universidad Miguel Hernández, Cra de Valencia S/N, Sant Joan d’Alacant, 03550 Alicante, Spain;
- Correspondence: (J.V.); (L.M.G.)
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8
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Szule JA. Hypothesis Relating the Structure, Biochemistry and Function of Active Zone Material Macromolecules at a Neuromuscular Junction. Front Synaptic Neurosci 2022; 13:798225. [PMID: 35069169 PMCID: PMC8766674 DOI: 10.3389/fnsyn.2021.798225] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2021] [Accepted: 12/14/2021] [Indexed: 12/22/2022] Open
Abstract
This report integrates knowledge of in situ macromolecular structures and synaptic protein biochemistry to propose a unified hypothesis for the regulation of certain vesicle trafficking events (i.e., docking, priming, Ca2+-triggering, and membrane fusion) that lead to neurotransmitter secretion from specialized “active zones” of presynaptic axon terminals. Advancements in electron tomography, to image tissue sections in 3D at nanometer scale resolution, have led to structural characterizations of a network of different classes of macromolecules at the active zone, called “Active Zone Material’. At frog neuromuscular junctions, the classes of Active Zone Material macromolecules “top-masts”, “booms”, “spars”, “ribs” and “pins” direct synaptic vesicle docking while “pins”, “ribs” and “pegs” regulate priming to influence Ca2+-triggering and membrane fusion. Other classes, “beams”, “steps”, “masts”, and “synaptic vesicle luminal filaments’ likely help organize and maintain the structural integrity of active zones. Extensive studies on the biochemistry that regulates secretion have led to comprehensive characterizations of the many conserved proteins universally involved in these trafficking events. Here, a hypothesis including a partial proteomic atlas of Active Zone Material is presented which considers the common roles, binding partners, physical features/structure, and relative positioning in the axon terminal of both the proteins and classes of macromolecules involved in the vesicle trafficking events. The hypothesis designates voltage-gated Ca2+ channels and Ca2+-gated K+ channels to ribs and pegs that are connected to macromolecules that span the presynaptic membrane at the active zone. SNARE proteins (Syntaxin, SNAP25, and Synaptobrevin), SNARE-interacting proteins Synaptotagmin, Munc13, Munc18, Complexin, and NSF are designated to ribs and/or pins. Rab3A and Rabphillin-3A are designated to top-masts and/or booms and/or spars. RIM, Bassoon, and Piccolo are designated to beams, steps, masts, ribs, spars, booms, and top-masts. Spectrin is designated to beams. Lastly, the luminal portions of SV2 are thought to form the bulk of the observed synaptic vesicle luminal filaments. The goal here is to help direct future studies that aim to bridge Active Zone Material structure, biochemistry, and function to ultimately determine how it regulates the trafficking events in vivo that lead to neurotransmitter secretion.
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Petropavlovskiy A, Kogut J, Leekha A, Townsend C, Sanders S. A sticky situation: regulation and function of protein palmitoylation with a spotlight on the axon and axon initial segment. Neuronal Signal 2021; 5:NS20210005. [PMID: 34659801 PMCID: PMC8495546 DOI: 10.1042/ns20210005] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2021] [Revised: 09/19/2021] [Accepted: 09/21/2021] [Indexed: 11/17/2022] Open
Abstract
In neurons, the axon and axon initial segment (AIS) are critical structures for action potential initiation and propagation. Their formation and function rely on tight compartmentalisation, a process where specific proteins are trafficked to and retained at distinct subcellular locations. One mechanism which regulates protein trafficking and association with lipid membranes is the modification of protein cysteine residues with the 16-carbon palmitic acid, known as S-acylation or palmitoylation. Palmitoylation, akin to phosphorylation, is reversible, with palmitate cycling being mediated by substrate-specific enzymes. Palmitoylation is well-known to be highly prevalent among neuronal proteins and is well studied in the context of the synapse. Comparatively, how palmitoylation regulates trafficking and clustering of axonal and AIS proteins remains less understood. This review provides an overview of the current understanding of the biochemical regulation of palmitoylation, its involvement in various neurological diseases, and the most up-to-date perspective on axonal palmitoylation. Through a palmitoylation analysis of the AIS proteome, we also report that an overwhelming proportion of AIS proteins are likely palmitoylated. Overall, our review and analysis confirm a central role for palmitoylation in the formation and function of the axon and AIS and provide a resource for further exploration of palmitoylation-dependent protein targeting to and function at the AIS.
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Affiliation(s)
- Andrey A. Petropavlovskiy
- Department of Molecular and Cellular Biology, University of Guelph, 50 Stone Rd E, Guelph N1G 2W1, Ontario, Canada
| | - Jordan A. Kogut
- Department of Molecular and Cellular Biology, University of Guelph, 50 Stone Rd E, Guelph N1G 2W1, Ontario, Canada
| | - Arshia Leekha
- Department of Molecular and Cellular Biology, University of Guelph, 50 Stone Rd E, Guelph N1G 2W1, Ontario, Canada
| | - Charlotte A. Townsend
- Department of Molecular and Cellular Biology, University of Guelph, 50 Stone Rd E, Guelph N1G 2W1, Ontario, Canada
| | - Shaun S. Sanders
- Department of Molecular and Cellular Biology, University of Guelph, 50 Stone Rd E, Guelph N1G 2W1, Ontario, Canada
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Synaptotagmin-1-, Munc18-1-, and Munc13-1-dependent liposome fusion with a few neuronal SNAREs. Proc Natl Acad Sci U S A 2021; 118:2019314118. [PMID: 33468652 DOI: 10.1073/pnas.2019314118] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Neurotransmitter release is governed by eight central proteins among other factors: the neuronal SNAREs syntaxin-1, synaptobrevin, and SNAP-25, which form a tight SNARE complex that brings the synaptic vesicle and plasma membranes together; NSF and SNAPs, which disassemble SNARE complexes; Munc18-1 and Munc13-1, which organize SNARE complex assembly; and the Ca2+ sensor synaptotagmin-1. Reconstitution experiments revealed that Munc18-1, Munc13-1, NSF, and α-SNAP can mediate Ca2+-dependent liposome fusion between synaptobrevin liposomes and syntaxin-1-SNAP-25 liposomes, but high fusion efficiency due to uncontrolled SNARE complex assembly did not allow investigation of the role of synaptotagmin-1 on fusion. Here, we show that decreasing the synaptobrevin-to-lipid ratio in the corresponding liposomes to very low levels leads to inefficient fusion and that synaptotagmin-1 strongly stimulates fusion under these conditions. Such stimulation depends on Ca2+ binding to the two C2 domains of synaptotagmin-1. We also show that anchoring SNAP-25 on the syntaxin-1 liposomes dramatically enhances fusion. Moreover, we uncover a synergy between synaptotagmin-1 and membrane anchoring of SNAP-25, which allows efficient Ca2+-dependent fusion between liposomes bearing very low synaptobrevin densities and liposomes containing very low syntaxin-1 densities. Thus, liposome fusion in our assays is achieved with a few SNARE complexes in a manner that requires Munc18-1 and Munc13-1 and that depends on Ca2+ binding to synaptotagmin-1, all of which are fundamental features of neurotransmitter release in neurons.
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11
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de Paola M, Garrido F, Zanetti MN, Michaut MA. VAMPs sensitive to tetanus toxin are required for cortical granule exocytosis in mouse oocytes. Exp Cell Res 2021; 405:112629. [PMID: 34023392 DOI: 10.1016/j.yexcr.2021.112629] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2021] [Revised: 04/24/2021] [Accepted: 04/27/2021] [Indexed: 01/16/2023]
Abstract
Fusion of cortical granules with oocyte plasma membrane is one of the most significant secretory events to prevent polyspermy during oocyte activation. Cortical granule exocytosis (CGE) is distinct from most other exocytosis because cortical granules are not renewed after secretion. However, it is thought to be mediated by SNARE complex, which mediates membrane fusion in other exocytoses. SNAREs proteins are divided into Q (glutamine)- and R (arginine)-SNAREs. Q-SNAREs include Syntaxins and SNAP25 family, and R-SNAREs include VAMPs family. In mouse oocytes, Syntaxin4 and SNAP23 have been involved in CGE; nevertheless, it is unknown if VAMP is required. Here, we demonstrated by RT-PCR and immunoblotting that VAMP1 and VAMP3 are expressed in mouse oocyte, and they localized in the cortical region of this cell. Using a functional assay to quantify CGE, we showed that tetanus toxin -which specifically cleavages VAMP1, VAMP2 or VAMP3- inhibited CGE suggesting that at least one VAMP was necessary. Function blocking assays demonstrated that only the microinjection of anti-VAMP1 or anti-VAMP3 antibodies abolished CGE in activated oocytes. These findings demonstrate that R-SNAREs sensitive to tetanus toxin, VAMP1 and VAMP3 -but not VAMP2-, are required for CGE and demonstrate that CGE is mediated by the SNARE complex.
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Affiliation(s)
- Matilde de Paola
- Laboratorio de Biología Reproductiva y Molecular, Instituto de Histología y Embriología, Universidad Nacional de Cuyo-CONICET, Av. Libertador 80, 5500, Mendoza, Argentina; Facultad de Ciencias Médicas, Universidad Nacional de Cuyo, Av. Libertador 80, 5500, Mendoza, Argentina
| | - Facundo Garrido
- Laboratorio de Biología Reproductiva y Molecular, Instituto de Histología y Embriología, Universidad Nacional de Cuyo-CONICET, Av. Libertador 80, 5500, Mendoza, Argentina
| | - María N Zanetti
- Laboratorio de Biología Reproductiva y Molecular, Instituto de Histología y Embriología, Universidad Nacional de Cuyo-CONICET, Av. Libertador 80, 5500, Mendoza, Argentina
| | - Marcela Alejandra Michaut
- Laboratorio de Biología Reproductiva y Molecular, Instituto de Histología y Embriología, Universidad Nacional de Cuyo-CONICET, Av. Libertador 80, 5500, Mendoza, Argentina; Facultad de Ciencias Exactas y Naturales, Universidad Nacional de Cuyo, Padre Jorge Contreras, 1300, Mendoza, Argentina.
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12
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Suazo KF, Park KY, Distefano MD. A Not-So-Ancient Grease History: Click Chemistry and Protein Lipid Modifications. Chem Rev 2021; 121:7178-7248. [PMID: 33821625 DOI: 10.1021/acs.chemrev.0c01108] [Citation(s) in RCA: 40] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Protein lipid modification involves the attachment of hydrophobic groups to proteins via ester, thioester, amide, or thioether linkages. In this review, the specific click chemical reactions that have been employed to study protein lipid modification and their use for specific labeling applications are first described. This is followed by an introduction to the different types of protein lipid modifications that occur in biology. Next, the roles of click chemistry in elucidating specific biological features including the identification of lipid-modified proteins, studies of their regulation, and their role in diseases are presented. A description of the use of protein-lipid modifying enzymes for specific labeling applications including protein immobilization, fluorescent labeling, nanostructure assembly, and the construction of protein-drug conjugates is presented next. Concluding remarks and future directions are presented in the final section.
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Affiliation(s)
- Kiall F Suazo
- Department of Chemistry, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Keun-Young Park
- Department of Chemistry, University of Minnesota, Minneapolis, Minnesota 55455, United States
| | - Mark D Distefano
- Department of Chemistry, University of Minnesota, Minneapolis, Minnesota 55455, United States
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13
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Melland H, Carr EM, Gordon SL. Disorders of synaptic vesicle fusion machinery. J Neurochem 2020; 157:130-164. [PMID: 32916768 DOI: 10.1111/jnc.15181] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Revised: 08/20/2020] [Accepted: 08/26/2020] [Indexed: 12/11/2022]
Abstract
The revolution in genetic technology has ushered in a new age for our understanding of the underlying causes of neurodevelopmental, neuromuscular and neurodegenerative disorders, revealing that the presynaptic machinery governing synaptic vesicle fusion is compromised in many of these neurological disorders. This builds upon decades of research showing that disturbance to neurotransmitter release via toxins can cause acute neurological dysfunction. In this review, we focus on disorders of synaptic vesicle fusion caused either by toxic insult to the presynapse or alterations to genes encoding the key proteins that control and regulate fusion: the SNARE proteins (synaptobrevin, syntaxin-1 and SNAP-25), Munc18, Munc13, synaptotagmin, complexin, CSPα, α-synuclein, PRRT2 and tomosyn. We discuss the roles of these proteins and the cellular and molecular mechanisms underpinning neurological deficits in these disorders.
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Affiliation(s)
- Holly Melland
- The Florey Institute of Neuroscience and Mental Health, Melbourne Dementia Research Centre, The University of Melbourne, Melbourne, Vic., Australia
| | - Elysa M Carr
- The Florey Institute of Neuroscience and Mental Health, Melbourne Dementia Research Centre, The University of Melbourne, Melbourne, Vic., Australia
| | - Sarah L Gordon
- The Florey Institute of Neuroscience and Mental Health, Melbourne Dementia Research Centre, The University of Melbourne, Melbourne, Vic., Australia
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14
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Shimell JJ, Shah BS, Cain SM, Thouta S, Kuhlmann N, Tatarnikov I, Jovellar DB, Brigidi GS, Kass J, Milnerwood AJ, Snutch TP, Bamji SX. The X-Linked Intellectual Disability Gene Zdhhc9 Is Essential for Dendrite Outgrowth and Inhibitory Synapse Formation. Cell Rep 2020; 29:2422-2437.e8. [PMID: 31747610 DOI: 10.1016/j.celrep.2019.10.065] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2018] [Revised: 09/09/2019] [Accepted: 10/13/2019] [Indexed: 11/29/2022] Open
Abstract
Palmitoylation is a reversible post-translational lipid modification that facilitates vesicular transport and subcellular localization of modified proteins. This process is catalyzed by ZDHHC enzymes that are implicated in several neurological and neurodevelopmental disorders. Loss-of-function mutations in ZDHHC9 have been identified in patients with X-linked intellectual disability (XLID) and associated with increased epilepsy risk. Loss of Zdhhc9 function in hippocampal cultures leads to shorter dendritic arbors and fewer inhibitory synapses, altering the ratio of excitatory-to-inhibitory inputs formed onto Zdhhc9-deficient cells. While Zdhhc9 promotes dendrite outgrowth through the palmitoylation of the GTPase Ras, it promotes inhibitory synapse formation through the palmitoylation of another GTPase, TC10. Zdhhc9 knockout mice exhibit seizure-like activity together with increased frequency and amplitude of both spontaneous and miniature excitatory and inhibitory postsynaptic currents. These findings present a plausible mechanism for how the loss of ZDHHC9 function may contribute to XLID and epilepsy.
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Affiliation(s)
- Jordan J Shimell
- Department of Cellular and Physiological Sciences, Djavad Mowafaghian Centre for Brain Health, University of British Columbia, 2350 Health Sciences Mall, Vancouver, BC V6T 1Z3, Canada
| | - Bhavin S Shah
- Department of Cellular and Physiological Sciences, Djavad Mowafaghian Centre for Brain Health, University of British Columbia, 2350 Health Sciences Mall, Vancouver, BC V6T 1Z3, Canada
| | - Stuart M Cain
- Michael Smith Laboratories, Djavad Mowafaghian Centre for Brain Health, University of British Columbia, 2215 Wesbrook Mall, Vancouver, BC V6T 1Z3, Canada
| | - Samrat Thouta
- Michael Smith Laboratories, Djavad Mowafaghian Centre for Brain Health, University of British Columbia, 2215 Wesbrook Mall, Vancouver, BC V6T 1Z3, Canada
| | - Naila Kuhlmann
- Montreal Neurological Institute, Department of Neurology and Neurosurgery, McGill University, 3801 University Street, Montreal, QC H3A 2B4, Canada
| | - Igor Tatarnikov
- Montreal Neurological Institute, Department of Neurology and Neurosurgery, McGill University, 3801 University Street, Montreal, QC H3A 2B4, Canada
| | - D Blair Jovellar
- Department of Cellular and Physiological Sciences, Djavad Mowafaghian Centre for Brain Health, University of British Columbia, 2350 Health Sciences Mall, Vancouver, BC V6T 1Z3, Canada
| | - G Stefano Brigidi
- Department of Cellular and Physiological Sciences, Djavad Mowafaghian Centre for Brain Health, University of British Columbia, 2350 Health Sciences Mall, Vancouver, BC V6T 1Z3, Canada
| | - Jennifer Kass
- Michael Smith Laboratories, Djavad Mowafaghian Centre for Brain Health, University of British Columbia, 2215 Wesbrook Mall, Vancouver, BC V6T 1Z3, Canada
| | - Austen J Milnerwood
- Montreal Neurological Institute, Department of Neurology and Neurosurgery, McGill University, 3801 University Street, Montreal, QC H3A 2B4, Canada
| | - Terrance P Snutch
- Michael Smith Laboratories, Djavad Mowafaghian Centre for Brain Health, University of British Columbia, 2215 Wesbrook Mall, Vancouver, BC V6T 1Z3, Canada
| | - Shernaz X Bamji
- Department of Cellular and Physiological Sciences, Djavad Mowafaghian Centre for Brain Health, University of British Columbia, 2350 Health Sciences Mall, Vancouver, BC V6T 1Z3, Canada.
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15
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Shao K, Li F, Yang Y, Wang N, Gao XD, Nakanishi H. Characteristics of SNARE proteins are defined by distinctive properties of SNARE motifs. Biochim Biophys Acta Gen Subj 2020; 1864:129658. [PMID: 32512168 DOI: 10.1016/j.bbagen.2020.129658] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2019] [Revised: 05/16/2020] [Accepted: 06/03/2020] [Indexed: 11/28/2022]
Abstract
BACKGROUND Syntaxin-1A and Sso1 are syntaxin family SNARE proteins engaged in synaptic vesicle fusion and yeast exocytosis. The syntaxin-1A SNARE motif can form a fusogenic SNARE complex with Sso1 partners. However, a chimera in which the SNARE motif in syntaxin-1A is introduced into Sso1 was not functional in yeast because the chimera is retained in the ER. Through the analysis of the transport defect of Sso1/syntaxin-1A chimeric SNAREs, we found that their SNARE motifs have distinctive properties. METHODS Sso1, syntaxin-1A, and Sso1/syntaxin-1A chimeric SNAREs were expressed in yeast cells and their localization and interaction with other SNAREs are analyzed. RESULTS SNARE proteins containing the syntaxin-1A SNARE motif exhibit a transport defect because they form a cis-SNARE complex in the ER. Ectopic SNARE complex formation can be prevented in syntaxin-1A by binding to a Sec1/Munc-18-like (SM) protein. In contrast, the SNARE motif of Sso1 does not form an ectopic SNARE complex. Additionally, we found that the SNARE motif in syntaxin-1A, but not that in Sso1, self-interacts, even when it is in the inactive form and bound to the SM protein. CONCLUSIONS The SNARE motif in syntaxin-1A, but not in Sso1, likely forms ectopic SNARE complex. Because of this property, the SM protein is necessary for syntaxin-1A to prevent its promiscuous assembly and to promote its export from the ER. GENERAL SIGNIFICANCE Properties of SNARE motifs affect characteristics of SNARE proteins. The regulatory mechanisms of SNARE proteins are, in part, designed to handle such properties.
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Affiliation(s)
- Kankai Shao
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, China
| | - Feng Li
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, China
| | - Yan Yang
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, China
| | - Ning Wang
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, China
| | - Xiao-Dong Gao
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, China.
| | - Hideki Nakanishi
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, China.
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Disabling Gβγ-SNAP-25 interaction in gene-targeted mice results in enhancement of long-term potentiation at Schaffer collateral-CA1 synapses in the hippocampus. Neuroreport 2020; 30:695-699. [PMID: 31095110 DOI: 10.1097/wnr.0000000000001258] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Three SNARE proteins, SNAP-25, syntaxin 1A, and VAMP2 or synaptobrevin 2, constitute the minimal functional machinery needed for the regulated secretion of neurotransmitters. Dynamic changes in the regulated release of neurotransmitters are associated with the induction of long-term plasticity at central synapses. In-vitro studies have validated the C-terminus of SNAP-25 as a target for inhibitory Gi/o-coupled G-protein coupled receptors at a number of synapses. The physiological consequences of the interaction between Gi/o proteins and SNAP-25 in the context of activity-dependent long-term synaptic plasticity are not well understood. Here, we report direct ex-vivo evidence of the involvement of the C-terminus of SNAP-25 in inducing long-term potentiation of synaptic strength at Schaffer collateral-CA1 synapses using a gene-targeted mouse model with truncated C-terminus (carboxyl terminus) of SNAP-25. It has been shown previously that truncation of the three extreme C-terminal residues in SNAP-25[INCREMENT]3 homozygote mice reduces its interaction with the inhibitory Gβγ subunits two-fold. In in-vitro hippocampal slices, we show that these SNAP-25[INCREMENT]3 mice express significantly larger magnitude of long-term potentiation at hippocampal Schaffer collateral-CA1 synapses.
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17
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Gopaul KR, Irfan M, Miry O, Vose LR, Moghadam A, Subah G, Hökfelt T, Bark C, Stanton PK. Developmental Time Course of SNAP-25 Isoforms Regulate Hippocampal Long-Term Synaptic Plasticity and Hippocampus-Dependent Learning. Int J Mol Sci 2020; 21:ijms21041448. [PMID: 32093363 PMCID: PMC7073020 DOI: 10.3390/ijms21041448] [Citation(s) in RCA: 2] [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: 12/31/2019] [Revised: 02/12/2020] [Accepted: 02/18/2020] [Indexed: 12/28/2022] Open
Abstract
SNAP-25 is essential to activity-dependent vesicle fusion and neurotransmitter release in the nervous system. During early development and adulthood, SNAP-25 appears to have differential influences on short- and long-term synaptic plasticity. The involvement of SNAP-25 in these processes may be different at hippocampal and neocortical synapses because of the presence of two different splice variants, which are developmentally regulated. We show here that the isoform SNAP-25a, which is expressed first developmentally in rodent brain, contributes to developmental regulation of the expression of both long-term depression (LTD) and long-term potentiation (LTP) at Schaffer collateral-CA1 synapses in the hippocampus. In one month old mice lacking the developmentally later expressed isoform SNAP-25b, Schaffer collateral-CA1 synapses showed faster release kinetics, decreased LTP and enhanced LTD. By four months of age, SNAP-25b-deficient mice appeared to have compensated for the lack of the adult SNAP-25b isoform, now exhibiting larger LTP and no differences in LTD compared to wild type mice. Interestingly, learning a hippocampus-dependent task reversed the reductions in LTP, but not LTD, seen at one month of age. In four month old adult mice, learning prevented the compensatory up-regulation of LTD that we observed prior to training. These findings support the hypothesis that SNAP-25b promotes stronger LTP and weakens LTD at Schaffer collateral-CA1 synapses in young mice, and suggest that compensatory mechanisms can reverse alterations in synaptic plasticity associated with a lack of SNAP-25b, once mice reach adulthood.
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Affiliation(s)
- Katisha R. Gopaul
- Department of Cell Biology & Anatomy, New York Medical College, Valhalla, NY 10595, USA; (K.R.G.); (M.I.); (O.M.); (L.R.V.); (A.M.); (G.S.)
| | - Muhammad Irfan
- Department of Cell Biology & Anatomy, New York Medical College, Valhalla, NY 10595, USA; (K.R.G.); (M.I.); (O.M.); (L.R.V.); (A.M.); (G.S.)
- Department of Neuroscience, Karolinska Institutet, 171 77 Stockholm, Sweden;
| | - Omid Miry
- Department of Cell Biology & Anatomy, New York Medical College, Valhalla, NY 10595, USA; (K.R.G.); (M.I.); (O.M.); (L.R.V.); (A.M.); (G.S.)
| | - Linnea R. Vose
- Department of Cell Biology & Anatomy, New York Medical College, Valhalla, NY 10595, USA; (K.R.G.); (M.I.); (O.M.); (L.R.V.); (A.M.); (G.S.)
| | - Alexander Moghadam
- Department of Cell Biology & Anatomy, New York Medical College, Valhalla, NY 10595, USA; (K.R.G.); (M.I.); (O.M.); (L.R.V.); (A.M.); (G.S.)
| | - Galadu Subah
- Department of Cell Biology & Anatomy, New York Medical College, Valhalla, NY 10595, USA; (K.R.G.); (M.I.); (O.M.); (L.R.V.); (A.M.); (G.S.)
| | - Tomas Hökfelt
- Department of Neuroscience, Karolinska Institutet, 171 77 Stockholm, Sweden;
| | - Christina Bark
- Department of Neuroscience, Karolinska Institutet, 171 77 Stockholm, Sweden;
- Correspondence: (C.B.); (P.K.S.); Tel. +46-085-248-6984 (C.B.); +1-914-594-4883 (P.K.S.)
| | - Patric K. Stanton
- Department of Cell Biology & Anatomy, New York Medical College, Valhalla, NY 10595, USA; (K.R.G.); (M.I.); (O.M.); (L.R.V.); (A.M.); (G.S.)
- Correspondence: (C.B.); (P.K.S.); Tel. +46-085-248-6984 (C.B.); +1-914-594-4883 (P.K.S.)
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18
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SNAP-25 Puts SNAREs at Center Stage in Metabolic Disease. Neuroscience 2019; 420:86-96. [DOI: 10.1016/j.neuroscience.2018.07.035] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2018] [Revised: 07/12/2018] [Accepted: 07/19/2018] [Indexed: 12/20/2022]
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19
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Öhrfelt A, Brinkmalm A, Dumurgier J, Zetterberg H, Bouaziz-Amar E, Hugon J, Paquet C, Blennow K. A Novel ELISA for the Measurement of Cerebrospinal Fluid SNAP-25 in Patients with Alzheimer’s Disease. Neuroscience 2019; 420:136-144. [DOI: 10.1016/j.neuroscience.2018.11.038] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2018] [Revised: 11/23/2018] [Accepted: 11/28/2018] [Indexed: 11/16/2022]
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20
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The SNAP-25 Protein Family. Neuroscience 2019; 420:50-71. [DOI: 10.1016/j.neuroscience.2018.09.020] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2018] [Revised: 08/31/2018] [Accepted: 09/14/2018] [Indexed: 01/04/2023]
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21
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Construction of functional chimeras of syntaxin-1A and its yeast orthologue, and their application to the yeast cell-based assay for botulinum neurotoxin serotype C. Biochim Biophys Acta Gen Subj 2019; 1863:129396. [PMID: 31302181 DOI: 10.1016/j.bbagen.2019.07.005] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2019] [Revised: 06/14/2019] [Accepted: 07/10/2019] [Indexed: 11/23/2022]
Abstract
BACKGROUND Botulinum neurotoxins (BoNTs) prevent synaptic transmission because they hydrolyze synaptic N-ethylmaleimide-sensitive factor attachment protein receptors (SNAREs). BoNT serotype C (BoNT/C) targets syntaxin-1A and SNAP-25, and is expected to be applied to cosmetic and therapeutic uses. SNAREs are evolutionally conserved proteins and in yeast a syntaxin-1A orthologue Sso1 is involved in exocytosis. The substrate specificity of BoNT/C is strict and it cannot cleave Sso1. METHODS Domain swapping and mutational screenings were performed to generate functional chimeras SNAREs of syntaxin-1A and Sso1. Such chimeras are expressed in yeast cells and assessed whether they are susceptible to BoNT/C digestion. RESULTS The Sso1 and syntaxin-1A chimera (Sso1/STX1A), in which the SNARE domain in Sso1 was replaced with that of syntaxin-1A, was not functional in yeast. The functional incompatibility of Sso1/STX1A was attributable to its accumulation in the ER. We found several mutations that could release Sso1/STX1A from the ER to make the chimera functional in yeast. Yeast cells harboring the mutant chimeras grew similarly to wild-type cells. However, unlike wild-type, yeast harboring the mutant chimeras exhibited a severe growth defect upon expression of BoNT/C. Results of further domain swapping analyses suggest that Sso1 is not digested by BoNT/C because it lacks a binding region to BoNT/C (α-exosite-binding region). CONCLUSIONS We obtained functional Sso1/STX1A chimeras, which can be applied to a yeast cell-based BoNT/C assay. BoNT/C can recognize these chimeras in a similar manner to syntaxin-1A. GENERAL SIGNIFICANCE The yeast cell-based BoNT/C assay would be useful to characterize and engineer BoNT/C.
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22
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Shaaban A, Dhara M, Frisch W, Harb A, Shaib AH, Becherer U, Bruns D, Mohrmann R. The SNAP-25 linker supports fusion intermediates by local lipid interactions. eLife 2019; 8:41720. [PMID: 30883328 PMCID: PMC6422494 DOI: 10.7554/elife.41720] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2018] [Accepted: 03/05/2019] [Indexed: 12/22/2022] Open
Abstract
SNAP-25 is an essential component of SNARE complexes driving fast Ca2+-dependent exocytosis. Yet, the functional implications of the tandem-like structure of SNAP-25 are unclear. Here, we have investigated the mechanistic role of the acylated “linker” domain that concatenates the two SNARE motifs within SNAP-25. Refuting older concepts of an inert connector, our detailed structure-function analysis in murine chromaffin cells demonstrates that linker motifs play a crucial role in vesicle priming, triggering, and fusion pore expansion. Mechanistically, we identify two synergistic functions of the SNAP-25 linker: First, linker motifs support t-SNARE interactions and accelerate ternary complex assembly. Second, the acylated N-terminal linker segment engages in local lipid interactions that facilitate fusion triggering and pore evolution, putatively establishing a favorable membrane configuration by shielding phospholipid headgroups and affecting curvature. Hence, the linker is a functional part of the fusion complex that promotes secretion by SNARE interactions as well as concerted lipid interplay.
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Affiliation(s)
- Ahmed Shaaban
- ZHMB, Saarland University, Homburg, Germany.,Department of Molecular Neurobiology, Max Planck Institute for Experimental Medicine, Göttingen, Germany
| | - Madhurima Dhara
- Institute for Physiology, Center of Integrative Physiology and Molecular Medicine, Saarland University, Homburg, Germany
| | - Walentina Frisch
- Institute for Physiology, Center of Integrative Physiology and Molecular Medicine, Saarland University, Homburg, Germany
| | - Ali Harb
- ZHMB, Saarland University, Homburg, Germany
| | - Ali H Shaib
- Department of Molecular Neurobiology, Max Planck Institute for Experimental Medicine, Göttingen, Germany
| | - Ute Becherer
- Institute for Physiology, Center of Integrative Physiology and Molecular Medicine, Saarland University, Homburg, Germany
| | - Dieter Bruns
- Institute for Physiology, Center of Integrative Physiology and Molecular Medicine, Saarland University, Homburg, Germany
| | - Ralf Mohrmann
- ZHMB, Saarland University, Homburg, Germany.,Institute for Physiology, Otto-von-Guericke University, Magdeburg, Germany.,Center for Behavioral Brain Science, Otto-von-Guericke University, Magdeburg, Germany
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23
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Ruchala P, Waring AJ, Cilluffo M, Whitelegge JP, Gundersen CB. Insights into the structure and molecular topography of the fatty acylated domain of synaptotagmin-1. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2019; 1861:677-684. [DOI: 10.1016/j.bbamem.2018.12.019] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/22/2018] [Revised: 12/12/2018] [Accepted: 12/29/2018] [Indexed: 12/12/2022]
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24
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Karmakar S, Sharma LG, Roy A, Patel A, Pandey LM. Neuronal SNARE complex: A protein folding system with intricate protein-protein interactions, and its common neuropathological hallmark, SNAP25. Neurochem Int 2018; 122:196-207. [PMID: 30517887 DOI: 10.1016/j.neuint.2018.12.001] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2018] [Revised: 11/08/2018] [Accepted: 12/01/2018] [Indexed: 12/26/2022]
Abstract
SNARE (Soluble NSF(N-ethylmaleimide-sensitive factor) Attachment Receptor) complex is a trimeric supramolecular organization of SNAP25, syntaxin, and VAMP which mediates fusion of synaptic vesicles with the presynaptic plasma membrane. The functioning of this entire protein assembly is dependent on its tetrahelical coiled coil structure alongside its interaction with a large spectrum of regulatory proteins like synaptotagmin, complexin, intersectin, etc. Defects arising in SNARE complex assembly due to mutations or faulty post-translational modifications are associated to severe synaptopathies like Schizophrenia and also proteopathies like Alzheimer's disease. The review primarily focuses on SNAP25, which is the prime contributor in the complex assembly. It is conceptualized that the network of protein interactions of this helical protein assists as a chaperoning system for attaining functional structure. Additionally, the innate disordered nature of SNAP25 and its amyloidogenic propensities have been highlighted employing computational methods. The intrinsic nature of SNAP25 is anticipated to form higher-order aggregates due to its cysteine rich domain, which is also a target for several post-translational modifications. Furthermore, the aberrations in the structure and expression profile of the protein display common patterns in the pathogenesis of a diverse synaptopathies and proteopathies. This work of SNARE literature aims to provide a new comprehensive outlook and research directions towards SNARE complex and presents SNAP25 as a common neuropathological hallmark which can be a diagnostic or therapeutic target.
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Affiliation(s)
- Srijeeb Karmakar
- Bio-Interface & Environmental Engineering Lab, Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati, Assam, 781039, India.
| | - Laipubam Gayatri Sharma
- Bio-Interface & Environmental Engineering Lab, Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati, Assam, 781039, India.
| | - Abhishek Roy
- Bio-Interface & Environmental Engineering Lab, Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati, Assam, 781039, India.
| | - Anjali Patel
- Bio-Interface & Environmental Engineering Lab, Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati, Assam, 781039, India.
| | - Lalit Mohan Pandey
- Bio-Interface & Environmental Engineering Lab, Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati, Assam, 781039, India.
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25
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Molecular mechanism of fusion pore formation driven by the neuronal SNARE complex. Proc Natl Acad Sci U S A 2018; 115:12751-12756. [PMID: 30482862 DOI: 10.1073/pnas.1816495115] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Release of neurotransmitters from synaptic vesicles begins with a narrow fusion pore, the structure of which remains unresolved. To obtain a structural model of the fusion pore, we performed coarse-grained molecular dynamics simulations of fusion between a nanodisc and a planar bilayer bridged by four partially unzipped SNARE complexes. The simulations revealed that zipping of SNARE complexes pulls the polar C-terminal residues of the synaptobrevin 2 and syntaxin 1A transmembrane domains to form a hydrophilic core between the two distal leaflets, inducing fusion pore formation. The estimated conductances of these fusion pores are in good agreement with experimental values. Two SNARE protein mutants inhibiting fusion experimentally produced no fusion pore formation. In simulations in which the nanodisc was replaced by a 40-nm vesicle, an extended hemifusion diaphragm formed but a fusion pore did not, indicating that restricted SNARE mobility is required for rapid fusion pore formation. Accordingly, rapid fusion pore formation also occurred in the 40-nm vesicle system when SNARE mobility was restricted by external forces. Removal of the restriction is required for fusion pore expansion.
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26
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Han W, Zhang M, Feng X, Gong G, Peng K, Zhang D. Genetic influences on creativity: an exploration of convergent and divergent thinking. PeerJ 2018; 6:e5403. [PMID: 30083479 PMCID: PMC6071619 DOI: 10.7717/peerj.5403] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2018] [Accepted: 07/18/2018] [Indexed: 12/23/2022] Open
Abstract
Previous studies on the genetic basis of creativity have mainly focused on the biological mechanisms of divergent thinking, possibly limiting the exploration of possible candidate genes. Taking a cognition-based perspective, the present study investigated the genetic basis for both the divergent and the convergent thinking components of creativity. A total of 321 Chinese university students were recruited to complete the Guildford Unusual Using Test (UUT) for divergent thinking capability and the Remote Associates Test (RAT) for convergent thinking capability. The polymorphism of rs2576037 in KATNAL2 was related to the fluency and originality component scores of UUT, and the polymorphism of rs5993883 in COMT, rs362584 in SNAP25 was related to the RAT performance. These effects remained significant after considering the influence of age, gender and intelligence. Our results provide new evidence for the genetic basis of creativity and reveal the important role of gene polymorphisms in divergent and convergent thinking.
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Affiliation(s)
- Wei Han
- Department of Psychology, Tsinghua University, Beijing, China
| | - Mi Zhang
- Department of Psychology, Tsinghua University, Beijing, China
| | - Xue Feng
- Education College, Yangtze University, Jingzhou, Hubei, China
| | | | - Kaiping Peng
- Department of Psychology, Tsinghua University, Beijing, China
| | - Dan Zhang
- Department of Psychology, Tsinghua University, Beijing, China
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27
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Garcia-Martinez V, Gimenez-Molina Y, Villanueva J, Darios FD, Davletov B, Gutiérrez LM. Emerging evidence for the modulation of exocytosis by signalling lipids. FEBS Lett 2018; 592:3493-3503. [PMID: 29962039 PMCID: PMC6282582 DOI: 10.1002/1873-3468.13178] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2018] [Revised: 06/01/2018] [Accepted: 06/27/2018] [Indexed: 01/22/2023]
Abstract
Membrane fusion is a key event in exocytosis of neurotransmitters and hormones stored in intracellular vesicles. In this process, soluble N‐ethylmaleimide sensitive factor attachment protein receptor (SNARE) proteins are essential components of the exocytotic molecular machinery, while lipids have been seen traditionally as structural elements. However, the so‐called signalling lipids, such as sphingosine and arachidonic acid, interact with SNAREs and directly modulate the frequency and mode of fusion events. Interestingly, recent work has proved that the sphingosine analogue FTY‐720, used in the treatment of multiple sclerosis, mimics the effects of signalling lipids. In the present Review, we discuss recent investigations suggesting that endogenous signalling lipids and synthetic analogues can modulate important physiological aspects of secretion, such as quantal release, vesicle recruitment into active sites, vesicle transport and even organelle fusion in the cytosol. Therefore, these compounds are far from being merely structural components of cellular membranes.
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Affiliation(s)
- Virginia Garcia-Martinez
- Instituto de Neurociencias de Alicante, Consejo Superior de Investigaciones Científicas-Universidad Miguel Hernández de Elche, Sant Joan d'Alacant, Alicante, Spain
| | - Yolanda Gimenez-Molina
- Instituto de Neurociencias de Alicante, Consejo Superior de Investigaciones Científicas-Universidad Miguel Hernández de Elche, Sant Joan d'Alacant, Alicante, Spain
| | - José Villanueva
- Instituto de Neurociencias de Alicante, Consejo Superior de Investigaciones Científicas-Universidad Miguel Hernández de Elche, Sant Joan d'Alacant, Alicante, Spain
| | - Frederic D Darios
- Inserm, U1127, CNRS, UMR 7225, Institut du Cerveau et de la Moelle épinière, ICM, Sorbonne Université, Paris, France
| | - Bazbek Davletov
- Department of Biomedical Sciences, University of Sheffield, UK
| | - Luis M Gutiérrez
- Instituto de Neurociencias de Alicante, Consejo Superior de Investigaciones Científicas-Universidad Miguel Hernández de Elche, Sant Joan d'Alacant, Alicante, Spain
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28
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Georgiev DD, Glazebrook JF. The quantum physics of synaptic communication via the SNARE protein complex. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2018; 135:16-29. [DOI: 10.1016/j.pbiomolbio.2018.01.006] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/24/2017] [Revised: 10/01/2017] [Accepted: 01/18/2018] [Indexed: 12/27/2022]
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29
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MacDougall DD, Lin Z, Chon NL, Jackman SL, Lin H, Knight JD, Anantharam A. The high-affinity calcium sensor synaptotagmin-7 serves multiple roles in regulated exocytosis. J Gen Physiol 2018; 150:783-807. [PMID: 29794152 PMCID: PMC5987875 DOI: 10.1085/jgp.201711944] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2017] [Accepted: 05/07/2018] [Indexed: 12/19/2022] Open
Abstract
MacDougall et al. review the structure and function of the calcium sensor synaptotagmin-7 in exocytosis. Synaptotagmin (Syt) proteins comprise a 17-member family, many of which trigger exocytosis in response to calcium. Historically, most studies have focused on the isoform Syt-1, which serves as the primary calcium sensor in synchronous neurotransmitter release. Recently, Syt-7 has become a topic of broad interest because of its extreme calcium sensitivity and diversity of roles in a wide range of cell types. Here, we review the known and emerging roles of Syt-7 in various contexts and stress the importance of its actions. Unique functions of Syt-7 are discussed in light of recent imaging, electrophysiological, and computational studies. Particular emphasis is placed on Syt-7–dependent regulation of synaptic transmission and neuroendocrine cell secretion. Finally, based on biochemical and structural data, we propose a mechanism to link Syt-7’s role in membrane fusion with its role in subsequent fusion pore expansion via strong calcium-dependent phospholipid binding.
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Affiliation(s)
| | - Zesen Lin
- Department of Pharmacology, University of Michigan, Ann Arbor, MI
| | - Nara L Chon
- Department of Chemistry, University of Colorado, Denver, CO
| | - Skyler L Jackman
- Vollum Institute, Oregon Health & Science University, Portland, OR
| | - Hai Lin
- Department of Chemistry, University of Colorado, Denver, CO
| | | | - Arun Anantharam
- Department of Pharmacology, University of Michigan, Ann Arbor, MI
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30
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Rapaport D, Fichtman B, Weidberg H, Sprecher E, Horowitz M. NEK3-mediated SNAP29 phosphorylation modulates its membrane association and SNARE fusion dependent processes. Biochem Biophys Res Commun 2018; 497:605-611. [DOI: 10.1016/j.bbrc.2018.02.116] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2018] [Accepted: 02/13/2018] [Indexed: 12/12/2022]
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31
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Rothman JE, Krishnakumar SS, Grushin K, Pincet F. Hypothesis - buttressed rings assemble, clamp, and release SNAREpins for synaptic transmission. FEBS Lett 2017; 591:3459-3480. [PMID: 28983915 PMCID: PMC5698743 DOI: 10.1002/1873-3468.12874] [Citation(s) in RCA: 60] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2017] [Revised: 10/02/2017] [Accepted: 10/02/2017] [Indexed: 11/21/2022]
Abstract
Neural networks are optimized to detect temporal coincidence on the millisecond timescale. Here, we offer a synthetic hypothesis based on recent structural insights into SNAREs and the C2 domain proteins to explain how synaptic transmission can keep this pace. We suggest that an outer ring of up to six curved Munc13 ‘MUN’ domains transiently anchored to the plasma membrane via its flanking domains surrounds a stable inner ring comprised of synaptotagmin C2 domains to serve as a work‐bench on which SNAREpins are templated. This ‘buttressed‐ring hypothesis’ affords straightforward answers to many principal and long‐standing questions concerning how SNAREpins can be assembled, clamped, and then released synchronously with an action potential.
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Affiliation(s)
- James E Rothman
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT, USA
| | - Shyam S Krishnakumar
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT, USA
| | - Kirill Grushin
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT, USA
| | - Frederic Pincet
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT, USA.,Laboratoire de Physique Statistique, Ecole Normale Supérieure, PSL Research University, Université Paris Diderot Sorbonne Paris Cité, Sorbonne Universités UPMC Univ, CNRS, Paris, France
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32
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Analysis of the brain palmitoyl-proteome using both acyl-biotin exchange and acyl-resin-assisted capture methods. Sci Rep 2017; 7:3299. [PMID: 28607426 PMCID: PMC5468251 DOI: 10.1038/s41598-017-03562-7] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2016] [Accepted: 05/02/2017] [Indexed: 11/18/2022] Open
Abstract
Palmitoylation is a reversible post-translational protein modification in which palmitic acid is added to cysteine residues, allowing association with different cellular membranes and subdomains. Recently, techniques have been developed to identify palmitoylation on a proteome-wide scale in order to reveal the full cellular complement of palmitoylated proteins. However, in the studies reported to date, there is considerable variation between the sets of identified palmitoyl-proteins and so there remains some uncertainty over what constitutes the definitive complement of palmitoylated proteins even in well-studied tissues such as brain. To address this issue, we used both acyl-biotin exchange and acyl-resin-assisted capture approaches using rat brain as a common protein source. The palmitoyl-proteins identified from each method by mass spectrometry were then compared with each other and previously published studies. There was generally good agreement between the two methods, although many identifications were unique to one method, indicating that at least some of the variability in published palmitoyl proteomes is due to methodological differences. By combining our new data with previous publications using mammalian cells/tissues, we propose a high confidence set of bona fide palmitoylated proteins in brain and provide a resource to help researchers prioritise candidate palmitoyl-proteins for investigation.
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33
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Zdanowicz R, Kreutzberger A, Liang B, Kiessling V, Tamm LK, Cafiso DS. Complexin Binding to Membranes and Acceptor t-SNAREs Explains Its Clamping Effect on Fusion. Biophys J 2017; 113:1235-1250. [PMID: 28456331 DOI: 10.1016/j.bpj.2017.04.002] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2017] [Revised: 03/31/2017] [Accepted: 04/04/2017] [Indexed: 02/07/2023] Open
Abstract
Complexin-1 is a SNARE effector protein that decreases spontaneous neurotransmitter release and enhances evoked release. Complexin binds to the fully assembled four-helical neuronal SNARE core complex as revealed in competing molecular models derived from x-ray crystallography. Presently, it is unclear how complexin binding to the postfusion complex accounts for its effects upon spontaneous and evoked release in vivo. Using a combination of spectroscopic and imaging methods, we characterize in molecular detail how complexin binds to the 1:1 plasma membrane t-SNARE complex of syntaxin-1a and SNAP-25 while simultaneously binding the lipid bilayer at both its N- and C-terminal ends. These interactions are cooperative, and binding to the prefusion acceptor t-SNARE complex is stronger than to the postfusion core complex. This complexin interaction reduces the affinity of synaptobrevin-2 for the 1:1 complex, thereby retarding SNARE assembly and vesicle docking in vitro. The results provide the basis for molecular models that account for the observed clamping effect of complexin beginning with the acceptor t-SNARE complex and the subsequent activation of the clamped complex by Ca2+ and synaptotagmin.
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Affiliation(s)
- Rafal Zdanowicz
- Department of Chemistry, University of Virginia, Charlottesville, Virginia; Center for Membrane and Cell Physiology, University of Virginia, Charlottesville, Virginia
| | - Alex Kreutzberger
- Center for Membrane and Cell Physiology, University of Virginia, Charlottesville, Virginia; Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, Virginia
| | - Binyong Liang
- Center for Membrane and Cell Physiology, University of Virginia, Charlottesville, Virginia; Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, Virginia
| | - Volker Kiessling
- Center for Membrane and Cell Physiology, University of Virginia, Charlottesville, Virginia; Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, Virginia
| | - Lukas K Tamm
- Center for Membrane and Cell Physiology, University of Virginia, Charlottesville, Virginia; Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, Virginia.
| | - David S Cafiso
- Department of Chemistry, University of Virginia, Charlottesville, Virginia; Center for Membrane and Cell Physiology, University of Virginia, Charlottesville, Virginia.
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34
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Shi Y, Zhang Y, Lou J. The influence of cell membrane and SNAP25 linker loop on the dynamics and unzipping of SNARE complex. PLoS One 2017; 12:e0176235. [PMID: 28426820 PMCID: PMC5398687 DOI: 10.1371/journal.pone.0176235] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2017] [Accepted: 04/08/2017] [Indexed: 11/29/2022] Open
Abstract
The soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) complex is composed of three neuronal proteins VAMP2, Syntaxin and SNAP25, which plays a core role during the process of membrane fusion. The zipping assembly of the SNARE complex releases energies and drives the vesicle and cell membrane into close proximity. In this study, we use all-atom molecular dynamics simulations to probe the dynamics of SNARE and its unzipping process in the context of membrane at the atomistic details. Our results indicated that the NTD of SNARE core domain is relatively more stable than CTD, which is in agreement with previous experiments. More importantly, possible interactions between the linker loop (LL) region of SNAP25 and VAMP2 are observed, suggests that the LL region may facilitate VAMP2 binding and SNARE initiation. The forced unzipping of SNARE in the presence of membrane and LL of SNAP25 reveals the possible pathway for energy generation of SNARE zipping, provides information to understand how force may regulate the cooperativity between the membrane and the SNARE complex.
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Affiliation(s)
- Yi Shi
- School of Life Sciences, University of Science and Technology of China, Hefei, Anhui, China
- Key Laboratory of RNA Biology, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
| | - Yong Zhang
- Key Laboratory of RNA Biology, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
| | - Jizhong Lou
- Key Laboratory of RNA Biology, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
- * E-mail:
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35
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Noor A, Zahid S. A review of the role of synaptosomal-associated protein 25 (SNAP-25) in neurological disorders. Int J Neurosci 2016; 127:805-811. [DOI: 10.1080/00207454.2016.1248240] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Affiliation(s)
- Aneeqa Noor
- Neurobiology Research Laboratory, Department of Healthcare Biotechnology, Atta-ur-Rahman School of Applied Biosciences, National University of Sciences and Technology, Islamabad, Pakistan
| | - Saadia Zahid
- Neurobiology Research Laboratory, Department of Healthcare Biotechnology, Atta-ur-Rahman School of Applied Biosciences, National University of Sciences and Technology, Islamabad, Pakistan
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36
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Cho E, Park M. Palmitoylation in Alzheimers disease and other neurodegenerative diseases. Pharmacol Res 2016; 111:133-151. [DOI: 10.1016/j.phrs.2016.06.008] [Citation(s) in RCA: 83] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/16/2016] [Revised: 06/07/2016] [Accepted: 06/08/2016] [Indexed: 12/13/2022]
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37
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Cellular compartmentation of energy metabolism: creatine kinase microcompartments and recruitment of B-type creatine kinase to specific subcellular sites. Amino Acids 2016; 48:1751-74. [DOI: 10.1007/s00726-016-2267-3] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2016] [Accepted: 05/27/2016] [Indexed: 12/13/2022]
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38
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Kreutzberger AJB, Liang B, Kiessling V, Tamm LK. Assembly and Comparison of Plasma Membrane SNARE Acceptor Complexes. Biophys J 2016; 110:2147-50. [PMID: 27178662 DOI: 10.1016/j.bpj.2016.04.011] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2016] [Revised: 03/11/2016] [Accepted: 04/08/2016] [Indexed: 12/16/2022] Open
Abstract
Neuronal exocytotic membrane fusion occurs on a fast timescale and is dependent on interactions between the vesicle SNARE synaptobrevin-2 and the plasma membrane SNAREs syntaxin-1a and SNAP-25 with a 1:1:1 stoichiometry. Reproducing fast fusion rates as observed in cells by reconstitution in vitro has been hindered by the spontaneous assembly of a 2:1 syntaxin-1a:SNAP-25 complex on target membranes that kinetically alters the binding of synaptobrevin-2. Previously, an artificial SNARE acceptor complex consisting of 1:1:1 syntaxin-1a(residues 183-288):SNAP-25:syb(residues 49-96) was found to greatly accelerate the rates of lipid mixing of reconstituted target and vesicle SNARE proteoliposomes. Here we present two (to our knowledge) new procedures to assemble membrane-bound 1:1 SNARE acceptor complexes that produce fast and efficient fusion without the need of the syb(49-96) peptide. In the first procedure, syntaxin-1a is purified in a strictly monomeric form and subsequently assembled with SNAP-25 in detergent with the correct 1:1 stoichiometry. In the second procedure, monomeric syntaxin-1a and dodecylated (d-)SNAP-25 are separately reconstituted into proteoliposomes and subsequently assembled in the plane of merged target lipid bilayers. Examining single particle fusion between synaptobrevin-2 proteoliposomes and planar-supported bilayers containing the two different SNARE acceptor complexes revealed similar fast rates of fusion. Changing the stoichiometry of syntaxin-1a and d-SNAP-25 in the target bilayer had significant effects on docking, but little effect on the rates of synaptobrevin-2 proteoliposome fusion.
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Affiliation(s)
- Alex J B Kreutzberger
- Center for Membrane and Cell Physiology and Department of Molecular Physiology & Biological Physics, University of Virginia, Charlottesville, Virginia
| | - Binyong Liang
- Center for Membrane and Cell Physiology and Department of Molecular Physiology & Biological Physics, University of Virginia, Charlottesville, Virginia
| | - Volker Kiessling
- Center for Membrane and Cell Physiology and Department of Molecular Physiology & Biological Physics, University of Virginia, Charlottesville, Virginia
| | - Lukas K Tamm
- Center for Membrane and Cell Physiology and Department of Molecular Physiology & Biological Physics, University of Virginia, Charlottesville, Virginia.
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39
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Cupertino RB, Kappel DB, Bandeira CE, Schuch JB, da Silva BS, Müller D, Bau CHD, Mota NR. SNARE complex in developmental psychiatry: neurotransmitter exocytosis and beyond. J Neural Transm (Vienna) 2016; 123:867-83. [DOI: 10.1007/s00702-016-1514-9] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2015] [Accepted: 01/20/2016] [Indexed: 12/31/2022]
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40
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Burkhardt P. The origin and evolution of synaptic proteins - choanoflagellates lead the way. ACTA ACUST UNITED AC 2015; 218:506-14. [PMID: 25696814 DOI: 10.1242/jeb.110247] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The origin of neurons was a key event in evolution, allowing metazoans to evolve rapid behavioral responses to environmental cues. Reconstructing the origin of synaptic proteins promises to reveal their ancestral functions and might shed light on the evolution of the first neuron-like cells in metazoans. By analyzing the genomes of diverse metazoans and their closest relatives, the evolutionary history of diverse presynaptic and postsynaptic proteins has been reconstructed. These analyses revealed that choanoflagellates, the closest relatives of metazoans, possess diverse synaptic protein homologs. Recent studies have now begun to investigate their ancestral functions. A primordial neurosecretory apparatus in choanoflagellates was identified and it was found that the mechanism, by which presynaptic proteins required for secretion of neurotransmitters interact, is conserved in choanoflagellates and metazoans. Moreover, studies on the postsynaptic protein homolog Homer revealed unexpected localization patterns in choanoflagellates and new binding partners, both which are conserved in metazoans. These findings demonstrate that the study of choanoflagellates can uncover ancient and previously undescribed functions of synaptic proteins.
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Affiliation(s)
- Pawel Burkhardt
- Marine Biological Association, The Laboratory, Citadel Hill, Plymouth PL1 2PB, UK
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41
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Scolari S, Imkeller K, Jolmes F, Veit M, Herrmann A, Schwarzer R. Modulation of cell surface transport and lipid raft localization by the cytoplasmic tail of the influenza virus hemagglutinin. Cell Microbiol 2015; 18:125-36. [PMID: 26243691 PMCID: PMC7162421 DOI: 10.1111/cmi.12491] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2015] [Revised: 06/28/2015] [Accepted: 07/13/2015] [Indexed: 11/30/2022]
Abstract
Viral glycoproteins are highly variable in their primary structure, but on the other hand feature a high functional conservation to fulfil their versatile tasks during the pathogenic life cycle. Typically, all protein domains are optimized in that indispensable functions can be assigned to small conserved motifs or even individual amino acids. The cytoplasmic tail of many viral spike proteins, although of particular relevance for the virus biology, is often only insufficiently characterized. Hemagglutinin (HA), the receptor-binding protein of the influenza virus comprises a short cytoplasmic tail of 13 amino acids that exhibits three highly conserved palmitoylation sites. However, the particular importance of these modifications and the tail in general for intracellular trafficking and lateral membrane organization remains elusive. In this study, we generated HA core proteins consisting of transmembrane domain, cytoplasmic tail and a minor part of the ectodomain, tagged with a yellow fluorescent protein. Different mutation and truncation variants of these chimeric proteins were investigated using confocal microscopy, to characterize the role of cytoplasmic tail and palmitoylation for the intracellular trafficking to plasma membrane and Golgi apparatus. In addition, we assessed raft partitioning of the variants by Foerster resonance energy transfer with an established raft marker. We revealed a substantial influence of the cytoplasmic tail length on the intracellular distribution and surface exposure of the proteins. A complete removal of the tail hampers a physiological trafficking of the protein, whereas a partial truncation can be compensated by cytoplasmic palmitoylations. Plasma membrane raft partitioning on the other hand was found to imperatively require palmitoylations, and the cysteine at position 551 turned out to be of most relevance. Our data shed further light on the tight interconnection between cytoplasmic elements and intracellular trafficking and suggest a function of HA palmitoylations in both lateral sorting and anterograde trafficking of the glycoprotein.
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Affiliation(s)
- Silvia Scolari
- Department of Biology, Molecular Biophysics, Humboldt University Berlin, 10115, Berlin, Germany
| | - Katharina Imkeller
- Department of Biology, Molecular Biophysics, Humboldt University Berlin, 10115, Berlin, Germany
| | - Fabian Jolmes
- Department of Biology, Molecular Biophysics, Humboldt University Berlin, 10115, Berlin, Germany
| | - Michael Veit
- Department of Immunology and Molecular Biology, Free University, 14163, Berlin, Germany
| | - Andreas Herrmann
- Department of Biology, Molecular Biophysics, Humboldt University Berlin, 10115, Berlin, Germany
| | - Roland Schwarzer
- Department of Biology, Molecular Biophysics, Humboldt University Berlin, 10115, Berlin, Germany.,Department of Biological Chemistry, Weizmann Institute of Science, 76100, Rehovot, Israel
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42
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Meng J, Wang J. Role of SNARE proteins in tumourigenesis and their potential as targets for novel anti-cancer therapeutics. Biochim Biophys Acta Rev Cancer 2015; 1856:1-12. [PMID: 25956199 DOI: 10.1016/j.bbcan.2015.04.002] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2015] [Revised: 04/24/2015] [Accepted: 04/28/2015] [Indexed: 12/22/2022]
Abstract
The function of soluble N-ethylmaleimide-sensitive factor attachment protein receptors (SNAREs) in cellular trafficking, membrane fusion and vesicle release in synaptic nerve terminals is well characterised. Recent studies suggest that SNAREs are also important in the control of tumourigenesis through the regulation of multiple signalling and transportation pathways. The majority of published studies investigated the effects of knockdown/knockout or overexpression of particular SNAREs on the normal function of cells as well as their dysfunction in tumourigenesis promotion. SNAREs are involved in the regulation of cancer cell invasion, chemo-resistance, the transportation of autocrine and paracrine factors, autophagy, apoptosis and the phosphorylation of kinases essential for cancer cell biogenesis. This evidence highlights SNAREs as potential targets for novel cancer therapy. This is the first review to summarise the expression and role of SNAREs in cancer biology at the cellular level, their interaction with non-SNARE proteins and modulation of cellular signalling cascades. Finally, a strategy is proposed for developing novel anti-cancer therapeutics using targeted delivery of a SNARE-inactivating protease into malignant cells.
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Affiliation(s)
- Jianghui Meng
- Charles Institute of Dermatology, School of Medicine and Medical Sciences, University College Dublin, Belfield, Dublin 4, Ireland.
| | - Jiafu Wang
- International Centre for Neurotherapeutics, Dublin City University, Glasnevin, Dublin 9, Ireland.
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43
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Rosenbaum EE, Vasiljevic E, Cleland SC, Flores C, Colley NJ. The Gos28 SNARE protein mediates intra-Golgi transport of rhodopsin and is required for photoreceptor survival. J Biol Chem 2014; 289:32392-409. [PMID: 25261468 PMCID: PMC4239595 DOI: 10.1074/jbc.m114.585166] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2014] [Revised: 09/24/2014] [Indexed: 11/06/2022] Open
Abstract
SNARE proteins play indispensable roles in membrane fusion events in many cellular processes, including synaptic transmission and protein trafficking. Here, we characterize the Golgi SNARE protein, Gos28, and its role in rhodopsin (Rh1) transport through Drosophila photoreceptors. Mutations in gos28 lead to defective Rh1 trafficking and retinal degeneration. We have pinpointed a role for Gos28 in the intra-Golgi transport of Rh1, downstream from α-mannosidase-II in the medial- Golgi. We have confirmed the necessity of key residues in Gos28's SNARE motif and demonstrate that its transmembrane domain is not required for vesicle fusion, consistent with Gos28 functioning as a t-SNARE for Rh1 transport. Finally, we show that human Gos28 rescues both the Rh1 trafficking defects and retinal degeneration in Drosophila gos28 mutants, demonstrating the functional conservation of these proteins. Our results identify Gos28 as an essential SNARE protein in Drosophila photoreceptors and provide mechanistic insights into the role of SNAREs in neurodegenerative disease.
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Affiliation(s)
- Erica E Rosenbaum
- From the Department of Ophthalmology and Visual Sciences, Department of Genetics and The McPherson Eye Research Institute, University of Wisconsin, Madison, Wisconsin 53792
| | - Eva Vasiljevic
- From the Department of Ophthalmology and Visual Sciences, Department of Genetics and The McPherson Eye Research Institute, University of Wisconsin, Madison, Wisconsin 53792
| | - Spencer C Cleland
- From the Department of Ophthalmology and Visual Sciences, Department of Genetics and The McPherson Eye Research Institute, University of Wisconsin, Madison, Wisconsin 53792
| | - Carlos Flores
- From the Department of Ophthalmology and Visual Sciences, Department of Genetics and The McPherson Eye Research Institute, University of Wisconsin, Madison, Wisconsin 53792
| | - Nansi Jo Colley
- From the Department of Ophthalmology and Visual Sciences, Department of Genetics and The McPherson Eye Research Institute, University of Wisconsin, Madison, Wisconsin 53792
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44
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Oeste CL, Pinar M, Schink KO, Martínez-Turrión J, Stenmark H, Peñalva MA, Pérez-Sala D. An isoprenylation and palmitoylation motif promotes intraluminal vesicle delivery of proteins in cells from distant species. PLoS One 2014; 9:e107190. [PMID: 25207810 PMCID: PMC4160200 DOI: 10.1371/journal.pone.0107190] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2014] [Accepted: 08/07/2014] [Indexed: 12/22/2022] Open
Abstract
The C-terminal ends of small GTPases contain hypervariable sequences which may be posttranslationally modified by defined lipid moieties. The diverse structural motifs generated direct proteins towards specific cellular membranes or organelles. However, knowledge on the factors that determine these selective associations is limited. Here we show, using advanced microscopy, that the isoprenylation and palmitoylation motif of human RhoB (–CINCCKVL) targets chimeric proteins to intraluminal vesicles of endolysosomes in human cells, displaying preferential co-localization with components of the late endocytic pathway. Moreover, this distribution is conserved in distant species, including cells from amphibians, insects and fungi. Blocking lipidic modifications results in accumulation of CINCCKVL chimeras in the cytosol, from where they can reach endolysosomes upon release of this block. Remarkably, CINCCKVL constructs are sorted to intraluminal vesicles in a cholesterol-dependent process. In the lower species, neither the C-terminal sequence of RhoB, nor the endosomal distribution of its homologs are conserved; in spite of this, CINCCKVL constructs also reach endolysosomes in Xenopus laevis and insect cells. Strikingly, this behavior is prominent in the filamentous ascomycete fungus Aspergillus nidulans, in which GFP-CINCCKVL is sorted into endosomes and vacuoles in a lipidation-dependent manner and allows monitoring endosomal movement in live fungi. In summary, the isoprenylated and palmitoylated CINCCKVL sequence constitutes a specific structure which delineates an endolysosomal sorting strategy operative in phylogenetically diverse organisms.
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Affiliation(s)
- Clara L. Oeste
- Department of Chemical and Physical Biology, Centro de Investigaciones Biológicas, Consejo Superior de Investigaciones Científicas, Madrid, Spain
| | - Mario Pinar
- Department of Cellular and Molecular Biology, Centro de Investigaciones Biológicas, Consejo Superior de Investigaciones Científicas, Madrid, Spain
| | - Kay O. Schink
- Centre for Cancer Biomedicine, Faculty of Medicine, Oslo University Hospital, Oslo, Norway
| | - Javier Martínez-Turrión
- Department of Chemical and Physical Biology, Centro de Investigaciones Biológicas, Consejo Superior de Investigaciones Científicas, Madrid, Spain
| | - Harald Stenmark
- Centre for Cancer Biomedicine, Faculty of Medicine, Oslo University Hospital, Oslo, Norway
| | - Miguel A. Peñalva
- Department of Cellular and Molecular Biology, Centro de Investigaciones Biológicas, Consejo Superior de Investigaciones Científicas, Madrid, Spain
| | - Dolores Pérez-Sala
- Department of Chemical and Physical Biology, Centro de Investigaciones Biológicas, Consejo Superior de Investigaciones Científicas, Madrid, Spain
- * E-mail:
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45
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Meriney SD, Umbach JA, Gundersen CB. Fast, Ca2+-dependent exocytosis at nerve terminals: shortcomings of SNARE-based models. Prog Neurobiol 2014; 121:55-90. [PMID: 25042638 DOI: 10.1016/j.pneurobio.2014.07.001] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2013] [Revised: 04/14/2014] [Accepted: 07/03/2014] [Indexed: 11/30/2022]
Abstract
Investigations over the last two decades have made major inroads in clarifying the cellular and molecular events that underlie the fast, synchronous release of neurotransmitter at nerve endings. Thus, appreciable progress has been made in establishing the structural features and biophysical properties of the calcium (Ca2+) channels that mediate the entry into nerve endings of the Ca2+ ions that trigger neurotransmitter release. It is now clear that presynaptic Ca2+ channels are regulated at many levels and the interplay of these regulatory mechanisms is just beginning to be understood. At the same time, many lines of research have converged on the conclusion that members of the synaptotagmin family serve as the primary Ca2+ sensors for the action potential-dependent release of neurotransmitter. This identification of synaptotagmins as the proteins which bind Ca2+ and initiate the exocytotic fusion of synaptic vesicles with the plasma membrane has spurred widespread efforts to reveal molecular details of synaptotagmin's action. Currently, most models propose that synaptotagmin interfaces directly or indirectly with SNARE (soluble, N-ethylmaleimide sensitive factor attachment receptors) proteins to trigger membrane fusion. However, in spite of intensive efforts, the field has not achieved consensus on the mechanism by which synaptotagmins act. Concurrently, the precise sequence of steps underlying SNARE-dependent membrane fusion remains controversial. This review considers the pros and cons of the different models of SNARE-mediated membrane fusion and concludes by discussing a novel proposal in which synaptotagmins might directly elicit membrane fusion without the intervention of SNARE proteins in this final fusion step.
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Affiliation(s)
- Stephen D Meriney
- Department of Neuroscience, Center for Neuroscience, University of Pittsburgh, Pittsburgh, PA 15260, USA
| | - Joy A Umbach
- Department of Molecular and Medical Pharmacology, UCLA David Geffen School of Medicine, Los Angeles, CA 90095, USA
| | - Cameron B Gundersen
- Department of Molecular and Medical Pharmacology, UCLA David Geffen School of Medicine, Los Angeles, CA 90095, USA.
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Fröhlich M, Dejanovic B, Kashkar H, Schwarz G, Nussberger S. S-palmitoylation represents a novel mechanism regulating the mitochondrial targeting of BAX and initiation of apoptosis. Cell Death Dis 2014; 5:e1057. [PMID: 24525733 PMCID: PMC3944235 DOI: 10.1038/cddis.2014.17] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2013] [Revised: 12/23/2013] [Accepted: 01/02/2014] [Indexed: 12/19/2022]
Abstract
The intrinsic pathway of apoptotic cell death is mainly mediated by the BCL-2-associated X (BAX) protein through permeabilization of the mitochondrial outer membrane (MOM) and the concomitant release of cytochrome c into the cytosol. In healthy, non-apoptotic cells, BAX is predominantly localized in the cytosol and exhibits a dynamic shuttle cycle between the cytosol and the mitochondria. Thus, the initial association with mitochondria represents a critical regulatory step enabling BAX to insert into MOMs, promoting the release of cytochrome c and ultimately resulting in apoptosis. However, the molecular mode of how BAX associates with MOMs and whether a cellular regulatory mechanism governs this process is poorly understood. Here we show that in both primary tissues and cultured cells, the association with MOMs and the proapoptotic action of BAX is controlled by its S-palmitoylation at Cys-126. A lack of BAX palmitoylation reduced BAX mitochondrial translocation, BAX oligomerization, caspase activity and apoptosis. Furthermore, ectopic expression of specific palmitoyl transferases in cultured healthy cells increases BAX S-palmitoylation and accelerates apoptosis, whereas malignant tumor cells show reduced BAX S-palmitoylation consistent with their reduced BAX-mediated proapoptotic activity. Our findings suggest that S-palmitoylation of BAX at Cys126 is a key regulatory process of BAX-mediated apoptosis.
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Affiliation(s)
- M Fröhlich
- Institute of Biochemistry, Department of Chemistry and Center for Molecular Medicine, Cologne University, Zülpicher Strasse 47, Cologne 50674, Germany
| | - B Dejanovic
- Institute of Biochemistry, Department of Chemistry and Center for Molecular Medicine, Cologne University, Zülpicher Strasse 47, Cologne 50674, Germany
| | - H Kashkar
- Institute for Medical Microbiology, Immunology and Hygiene and Center for Molecular Medicine, Cologne University, Goldenfels Strasse 19-21, Cologne 50935, Germany
| | - G Schwarz
- Institute of Biochemistry, Department of Chemistry and Center for Molecular Medicine, Cologne University, Zülpicher Strasse 47, Cologne 50674, Germany
| | - S Nussberger
- 1] Institute of Biochemistry, Department of Chemistry and Center for Molecular Medicine, Cologne University, Zülpicher Strasse 47, Cologne 50674, Germany [2] Biophysics Department, Institute of Biology, University of Stuttgart, Pfaffenwaldring 57, Stuttgart 70550, Germany
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47
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Jia L, Chisari M, Maktabi MH, Sobieski C, Zhou H, Konopko AM, Martin BR, Mennerick SJ, Blumer KJ. A mechanism regulating G protein-coupled receptor signaling that requires cycles of protein palmitoylation and depalmitoylation. J Biol Chem 2014; 289:6249-57. [PMID: 24385443 DOI: 10.1074/jbc.m113.531475] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Reversible attachment and removal of palmitate or other long-chain fatty acids on proteins has been hypothesized, like phosphorylation, to control diverse biological processes. Indeed, palmitate turnover regulates Ras trafficking and signaling. Beyond this example, however, the functions of palmitate turnover on specific proteins remain poorly understood. Here, we show that a mechanism regulating G protein-coupled receptor signaling in neuronal cells requires palmitate turnover. We used hexadecyl fluorophosphonate or palmostatin B to inhibit enzymes in the serine hydrolase family that depalmitoylate proteins, and we studied R7 regulator of G protein signaling (RGS)-binding protein (R7BP), a palmitoylated allosteric modulator of R7 RGS proteins that accelerate deactivation of Gi/o class G proteins. Depalmitoylation inhibition caused R7BP to redistribute from the plasma membrane to endomembrane compartments, dissociated R7BP-bound R7 RGS complexes from Gi/o-gated G protein-regulated inwardly rectifying K(+) (GIRK) channels and delayed GIRK channel closure. In contrast, targeting R7BP to the plasma membrane with a polybasic domain and an irreversibly attached lipid instead of palmitate rendered GIRK channel closure insensitive to depalmitoylation inhibitors. Palmitate turnover therefore is required for localizing R7BP to the plasma membrane and facilitating Gi/o deactivation by R7 RGS proteins on GIRK channels. Our findings broaden the scope of biological processes regulated by palmitate turnover on specific target proteins. Inhibiting R7BP depalmitoylation may provide a means of enhancing GIRK activity in neurological disorders.
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Affiliation(s)
- Lixia Jia
- From the Departments of Cell Biology and Physiology
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48
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Synaptotagmins 1 and 2 as mediators of rapid exocytosis at nerve terminals: The dyad hypothesis. J Theor Biol 2013; 332:149-60. [DOI: 10.1016/j.jtbi.2013.04.029] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2013] [Accepted: 04/24/2013] [Indexed: 11/16/2022]
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49
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Abstract
Palmitoylation, the attachment of palmitate and other fatty acids on to cysteine residues, is a common post-translational modification of both integral and peripheral membrane proteins. Dynamic palmitoylation controls the intracellular distribution of peripheral membrane proteins by regulating membrane-cytosol exchange and/or by modifying the flux of the proteins through vesicular transport systems.
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50
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Lord C, Ferro-Novick S, Miller EA. The highly conserved COPII coat complex sorts cargo from the endoplasmic reticulum and targets it to the golgi. Cold Spring Harb Perspect Biol 2013; 5:5/2/a013367. [PMID: 23378591 DOI: 10.1101/cshperspect.a013367] [Citation(s) in RCA: 87] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Protein egress from the endoplasmic reticulum (ER) is driven by a conserved cytoplasmic coat complex called the COPII coat. The COPII coat complex contains an inner shell (Sec23/Sec24) that sorts cargo into ER-derived vesicles and an outer cage (Sec13/Sec31) that leads to coat polymerization. Once released from the ER, vesicles must tether to and fuse with the target membrane to deliver their protein and lipid contents. This delivery step also depends on the COPII coat, with coat proteins binding directly to tethering and regulatory factors. Recent findings have yielded new insight into how COPII-mediated vesicle traffic is regulated. Here we discuss the molecular basis of COPII-mediated ER-Golgi traffic, focusing on the surprising complexity of how ER-derived vesicles form, package diverse cargoes, and correctly target these cargoes to their destination.
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Affiliation(s)
- Christopher Lord
- Department of Cellular and Molecular Medicine, Howard Hughes Medical Institute, University of California at San Diego, La Jolla, CA 92093, USA
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