{"id":{"repo_id":"utswmed","oai_identifier":"oai:utswmed-ir.tdl.org:2152.5/1592"},"canonical_url":"https://search.dev.ndltd.org/etd/utswmed/oai:utswmed-ir.tdl.org:2152.5/1592","repository":{"repo_id":"utswmed","name":"University of Texas Southwestern Medical Center","base_url":"https://utswmed-ir.tdl.org/server/oai/request"},"display":{"title":"Insights into the Functions of Munc18-1 in Neurotransmitter Release","abstract":"Neurotransmitter release is an exquisitely regulated process that transmits signals between neurons. The release process includes: docking of synaptic vesicles at the active zone of the pre-synaptic plasma membrane, priming to a release ready state, and then membrane fusion and release of neurotransmitters triggered by Ca2+. Several conserved proteins are involved in regulating the entire process. The central membrane fusion machinery in neurons includes Munc18-1 and the SNARE proteins syntaxin-1, SNAP-25 and synaptobrevin. The SNAREs form tight SNARE complexes that bring the vesicle membrane and plasma membrane into close proximity and provide forces to induce membrane fusion. Munc18-1 is essential because deletion of Munc18-1 in mice leads to a complete loss of neurotransmitter secretion. However, its molecular mechanism of action is still unclear. This work is aimed to unravel the critical roles of Munc18-1 in regulating neurotransmitter release. The functions of Munc18-1 discovered so far are related to the SNAREs. Recently we found that Munc18-1 interacts with synaptobrevin and the SNARE four-helix bundle with week affinity, which have been shown to stimulate in vitro SNARE-dependent liposome fusion. Biophysical characterization of these two interactions could provide important information to uncover the roles of Munc18-1 in membrane fusion. Cross-linking and NMR spectroscopy experiments showed that Munc18-1 interacts with the C-terminus of the synaptobrevin SNARE motif through some positively charged residues located in its domain 3a. NMR spectroscopy and ITC experiments revealed that the Munc18-1 N-terminal domain interacts with the C-terminal part of synaptobrevin and syntaxin-1 on the SNARE four-helix bundle, and that the affinity is higher than full length Munc18-1. In our in vitro reconstitution experiments that try to establish the vital functions of Munc18-1 and Munc13 in neurotransmitter release, I found that Munc18-1 displaces SNAP-25 from syntaxin-1/SNAP-25 complex to form Munc18-1/syntaxin-1 complex on liposomes in the presence of NSF/α-SNAP/ATP. When NSF/α-SNAP were incorporated in the lipid mixing assays between synaptobrevin-liposmes and syntaxin-1/SNAP-25-liposomes, Munc18-1 together with Munc13 activate lipid mixing that is inhibited by NSF/α-SNAP. These results suggest that Munc18-1 functions with Munc13 to promote SNARE complex formation in an NSF/α-SNAP resistant manner and to guide the synaptic vesicle exocytosis through a tightly regulated pathway.","abstract_html":"Neurotransmitter release is an exquisitely regulated process that transmits signals between neurons. The release process includes: docking of synaptic vesicles at the active zone of the pre-synaptic plasma membrane, priming to a release ready state, and then membrane fusion and release of neurotransmitters triggered by Ca2+. Several conserved proteins are involved in regulating the entire process. The central membrane fusion machinery in neurons includes Munc18-1 and the SNARE proteins syntaxin-1, SNAP-25 and synaptobrevin. The SNAREs form tight SNARE complexes that bring the vesicle membrane and plasma membrane into close proximity and provide forces to induce membrane fusion. Munc18-1 is essential because deletion of Munc18-1 in mice leads to a complete loss of neurotransmitter secretion. However, its molecular mechanism of action is still unclear. This work is aimed to unravel the critical roles of Munc18-1 in regulating neurotransmitter release. The functions of Munc18-1 discovered so far are related to the SNAREs. Recently we found that Munc18-1 interacts with synaptobrevin and the SNARE four-helix bundle with week affinity, which have been shown to stimulate in vitro SNARE-dependent liposome fusion. Biophysical characterization of these two interactions could provide important information to uncover the roles of Munc18-1 in membrane fusion. Cross-linking and NMR spectroscopy experiments showed that Munc18-1 interacts with the C-terminus of the synaptobrevin SNARE motif through some positively charged residues located in its domain 3a. NMR spectroscopy and ITC experiments revealed that the Munc18-1 N-terminal domain interacts with the C-terminal part of synaptobrevin and syntaxin-1 on the SNARE four-helix bundle, and that the affinity is higher than full length Munc18-1. In our in vitro reconstitution experiments that try to establish the vital functions of Munc18-1 and Munc13 in neurotransmitter release, I found that Munc18-1 displaces SNAP-25 from syntaxin-1/SNAP-25 complex to form Munc18-1/syntaxin-1 complex on liposomes in the presence of NSF/α-SNAP/ATP. When NSF/α-SNAP were incorporated in the lipid mixing assays between synaptobrevin-liposmes and syntaxin-1/SNAP-25-liposomes, Munc18-1 together with Munc13 activate lipid mixing that is inhibited by NSF/α-SNAP. These results suggest that Munc18-1 functions with Munc13 to promote SNARE complex formation in an NSF/α-SNAP resistant manner and to guide the synaptic vesicle exocytosis through a tightly regulated pathway.","abstract_has_math":false,"creators":["Su, Lijing"],"institution":null,"degree_name":null,"degree_level":null,"degree_discipline":null,"degree_department":null,"school":null,"contributors":["Rizo-Rey, José","Luo, Xuelian","Kavalali, Ege T.","Liu, Yi"],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2015,"date_issued":"2015-06-01T21:38:13Z","date_published":"2015-06-01T21:38:13Z","updated_at":"2026-07-24T05:52:06Z","subjects":["Membrane Fusion","Munc18 Proteins","Nerve Tissue Proteins","Neurotransmitter Agents","Synaptic Vesicles"],"languages":["en"],"rights":[],"rights_urls":[],"identifier_entries":[{"key":"dc:identifier","label":"Identifier","values":["https://hdl.handle.net/2152.5/1592","910559212"],"render_values":[{"text":"https://hdl.handle.net/2152.5/1592","href":"https://hdl.handle.net/2152.5/1592","code":true},{"text":"910559212","href":null,"code":true}]}]},"links":{"outbound_url":"https://hdl.handle.net/2152.5/ETD-UTSWMED-2013-05-104","outbound_label":"Handle","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["Rizo-Rey, José","Luo, Xuelian","Kavalali, Ege T.","Liu, Yi"]},{"key":"dc:creator","label":"Author","values":["Su, Lijing"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date","label":"Dc Date","values":["2015-06-01T21:38:13Z","2013-05","2013-03-07","May 2013","2015-06-01T21:37:45Z"]},{"key":"dc:type","label":"Dc Type","values":["Thesis","Text"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["Membrane Fusion","Munc18 Proteins","Nerve Tissue Proteins","Neurotransmitter Agents","Synaptic Vesicles"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language","label":"Dc Language","values":["en"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["https://hdl.handle.net/2152.5/ETD-UTSWMED-2013-05-104","https://hdl.handle.net/2152.5/1592","910559212"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["Neurotransmitter release is an exquisitely regulated process that transmits signals between neurons. The release process includes: docking of synaptic vesicles at the active zone of the pre-synaptic plasma membrane, priming to a release ready state, and then membrane fusion and release of neurotransmitters triggered by Ca2+. Several conserved proteins are involved in regulating the entire process. The central membrane fusion machinery in neurons includes Munc18-1 and the SNARE proteins syntaxin-1, SNAP-25 and synaptobrevin. The SNAREs form tight SNARE complexes that bring the vesicle membrane and plasma membrane into close proximity and provide forces to induce membrane fusion. Munc18-1 is essential because deletion of Munc18-1 in mice leads to a complete loss of neurotransmitter secretion. However, its molecular mechanism of action is still unclear. This work is aimed to unravel the critical roles of Munc18-1 in regulating neurotransmitter release. The functions of Munc18-1 discovered so far are related to the SNAREs. Recently we found that Munc18-1 interacts with synaptobrevin and the SNARE four-helix bundle with week affinity, which have been shown to stimulate in vitro SNARE-dependent liposome fusion. Biophysical characterization of these two interactions could provide important information to uncover the roles of Munc18-1 in membrane fusion. Cross-linking and NMR spectroscopy experiments showed that Munc18-1 interacts with the C-terminus of the synaptobrevin SNARE motif through some positively charged residues located in its domain 3a. NMR spectroscopy and ITC experiments revealed that the Munc18-1 N-terminal domain interacts with the C-terminal part of synaptobrevin and syntaxin-1 on the SNARE four-helix bundle, and that the affinity is higher than full length Munc18-1. In our in vitro reconstitution experiments that try to establish the vital functions of Munc18-1 and Munc13 in neurotransmitter release, I found that Munc18-1 displaces SNAP-25 from syntaxin-1/SNAP-25 complex to form Munc18-1/syntaxin-1 complex on liposomes in the presence of NSF/α-SNAP/ATP. When NSF/α-SNAP were incorporated in the lipid mixing assays between synaptobrevin-liposmes and syntaxin-1/SNAP-25-liposomes, Munc18-1 together with Munc13 activate lipid mixing that is inhibited by NSF/α-SNAP. These results suggest that Munc18-1 functions with Munc13 to promote SNARE complex formation in an NSF/α-SNAP resistant manner and to guide the synaptic vesicle exocytosis through a tightly regulated pathway."]},{"key":"dc:format","label":"Dc Format","values":["application/pdf"]},{"key":"dc:title","label":"Title","values":["Insights into the Functions of Munc18-1 in Neurotransmitter Release"]}]}],"canonical_facts":{"dc:contributor":["Rizo-Rey, José","Luo, Xuelian","Kavalali, Ege T.","Liu, Yi"],"dc:creator":["Su, Lijing"],"dc:date":["2015-06-01T21:38:13Z","2013-05","2013-03-07","May 2013","2015-06-01T21:37:45Z"],"dc:description":["Neurotransmitter release is an exquisitely regulated process that transmits signals between neurons. The release process includes: docking of synaptic vesicles at the active zone of the pre-synaptic plasma membrane, priming to a release ready state, and then membrane fusion and release of neurotransmitters triggered by Ca2+. Several conserved proteins are involved in regulating the entire process. The central membrane fusion machinery in neurons includes Munc18-1 and the SNARE proteins syntaxin-1, SNAP-25 and synaptobrevin. The SNAREs form tight SNARE complexes that bring the vesicle membrane and plasma membrane into close proximity and provide forces to induce membrane fusion. Munc18-1 is essential because deletion of Munc18-1 in mice leads to a complete loss of neurotransmitter secretion. However, its molecular mechanism of action is still unclear. This work is aimed to unravel the critical roles of Munc18-1 in regulating neurotransmitter release. The functions of Munc18-1 discovered so far are related to the SNAREs. Recently we found that Munc18-1 interacts with synaptobrevin and the SNARE four-helix bundle with week affinity, which have been shown to stimulate in vitro SNARE-dependent liposome fusion. Biophysical characterization of these two interactions could provide important information to uncover the roles of Munc18-1 in membrane fusion. Cross-linking and NMR spectroscopy experiments showed that Munc18-1 interacts with the C-terminus of the synaptobrevin SNARE motif through some positively charged residues located in its domain 3a. NMR spectroscopy and ITC experiments revealed that the Munc18-1 N-terminal domain interacts with the C-terminal part of synaptobrevin and syntaxin-1 on the SNARE four-helix bundle, and that the affinity is higher than full length Munc18-1. In our in vitro reconstitution experiments that try to establish the vital functions of Munc18-1 and Munc13 in neurotransmitter release, I found that Munc18-1 displaces SNAP-25 from syntaxin-1/SNAP-25 complex to form Munc18-1/syntaxin-1 complex on liposomes in the presence of NSF/α-SNAP/ATP. When NSF/α-SNAP were incorporated in the lipid mixing assays between synaptobrevin-liposmes and syntaxin-1/SNAP-25-liposomes, Munc18-1 together with Munc13 activate lipid mixing that is inhibited by NSF/α-SNAP. These results suggest that Munc18-1 functions with Munc13 to promote SNARE complex formation in an NSF/α-SNAP resistant manner and to guide the synaptic vesicle exocytosis through a tightly regulated pathway."],"dc:format":["application/pdf"],"dc:identifier":["https://hdl.handle.net/2152.5/ETD-UTSWMED-2013-05-104","https://hdl.handle.net/2152.5/1592","910559212"],"dc:language":["en"],"dc:subject":["Membrane Fusion","Munc18 Proteins","Nerve Tissue Proteins","Neurotransmitter Agents","Synaptic Vesicles"],"dc:title":["Insights into the Functions of Munc18-1 in Neurotransmitter Release"],"dc:type":["Thesis","Text"]},"updated_at":"2026-07-24T05:52:06Z"}