title: Hemifusion arrest by complexin is relieved by Ca2+-synaptotagmin I.
abstract: Synaptic transmission relies on an exquisitely orchestrated series of protein-protein interactions. Here we show that fusion driven by neuronal SNAREs is inhibited by the regulatory protein complexin. Furthermore, inner-leaflet mixing is strongly impaired relative to total lipid mixing, indicating that inhibition by complexin arrests fusion at hemifusion. When the calcium sensor synaptotagmin is added in the presence of calcium, inhibition by complexin is relieved and full fusion rapidly proceeds.
authors.affiliation: Department of Biochemistry and Cell Biology, Rice University, 6100 Main Street MS-140, Houston, Texas 77005, USA.
authors.forename: Johanna R
authors.initials: JR
authors.lastname: Schaub
authors.forename: Xiaobing
authors.initials: X
authors.lastname: Lu
authors.forename: Blair
authors.initials: B
authors.lastname: Doneske
authors.forename: Yeon-Kyun
authors.initials: YK
authors.lastname: Shin
authors.forename: James A
authors.initials: JA
authors.lastname: McNew
mesh_terms: D033942:Adaptor Proteins, Vesicular Transport; D000818:Animals; D002118:Calcium / Q000378:metabolism; D029721:Drosophila Proteins / Q000235:genetics / Q000378:metabolism; D004926:Escherichia coli / Q000235:genetics; D047468:Immunoprecipitation; D008081:Liposomes / Q000378:metabolism; D008561:Membrane Fusion / Q000502:physiology; D051379:Mice; D009419:Nerve Tissue Proteins / Q000235:genetics / Q000378:metabolism*; D050600:SNARE Proteins / Q000235:genetics / Q000378:metabolism; D009435:Synaptic Transmission; D050863:Synaptotagmin I / Q000235:genetics / Q000378:metabolism*
chemical_list: D033942:Adaptor Proteins, Vesicular Transport; D029721:Drosophila Proteins; D008081:Liposomes; D009419:Nerve Tissue Proteins; D050600:SNARE Proteins; D050863:Synaptotagmin I; C095992:complexin I; D002118:Calcium