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dc.contributor.authorVasin, Alexander
dc.contributor.authorBykhovskaia, Maria
dc.contributor.authorVolfson, Dina
dc.contributor.authorLittleton, J. Troy
dc.date.accessioned2018-08-13T14:33:47Z
dc.date.available2018-08-13T14:33:47Z
dc.date.issued2016-11
dc.date.submitted2016-04
dc.identifier.issn0006-3495
dc.identifier.urihttp://hdl.handle.net/1721.1/117332
dc.description.abstractNeuronal transmitters are released from nerve terminals via the fusion of synaptic vesicles with the plasma membrane. Vesicles attach to membranes via a specialized protein machinery composed of membrane-attached (t-SNARE) and vesicle-attached (v-SNARE) proteins that zipper together to form a coiled-coil SNARE bundle that brings the two fusing membranes into close proximity. Neurotransmitter release may occur either in response to an action potential or through spontaneous fusion. A cytosolic protein, Complexin (Cpx), binds the SNARE complex and restricts spontaneous exocytosis by acting as a fusion clamp. We previously proposed a model in which the interaction between Cpx and the v-SNARE serves as a spring to prevent premature zippering of the SNARE complex, thereby reducing the likelihood of fusion. To test this model, we combined molecular-dynamics (MD) simulations and site-directed mutagenesis of Cpx and SNAREs in Drosophila. MD simulations of the Drosophila Cpx-SNARE complex demonstrated that Cpx's interaction with the v-SNARE promotes unraveling of the v-SNARE off the core SNARE bundle. We investigated clamping properties in the syx3-69paralytic mutant, which has a single-point mutation in the t-SNARE and displays enhanced spontaneous release. MD simulations demonstrated an altered interaction of Cpx with the SNARE bundle that hindered v-SNARE unraveling by Cpx, thus compromising clamping. We used our model to predict mutations that should enhance the ability of Cpx to prevent full assembly of the SNARE complex. MD simulations predicted that a weakened interaction between the Cpx accessory helix and the v-SNARE would enhance Cpx flexibility and thus promote separation of SNAREs, reducing spontaneous fusion. We generated transgenic Drosophila with mutations in Cpx and the v-SNARE that disrupted a salt bridge between these two proteins. As predicted, both lines demonstrated a selective inhibition in spontaneous release, suggesting that Cpx acts as a fusion clamp that restricts full SNARE zippering.en_US
dc.description.sponsorshipNational Institutes of Health (U.S.) (Grant R01 MH0999557)en_US
dc.description.sponsorshipNational Science Foundation (U.S.) (Grant ACI-1053575)en_US
dc.publisherElsevier BVen_US
dc.relation.isversionofhttp://dx.doi.org/10.1016/J.BPJ.2016.09.017en_US
dc.rightsCreative Commons Attribution-NonCommercial-NoDerivs Licenseen_US
dc.rights.urihttp://creativecommons.org/licenses/by-nc-nd/4.0/en_US
dc.sourceProf. Littleton via Courtney Crummetten_US
dc.titleInteraction of the Complexin Accessory Helix with Synaptobrevin Regulates Spontaneous Fusionen_US
dc.typeArticleen_US
dc.identifier.citationVasin, Alexander et al. “Interaction of the Complexin Accessory Helix with Synaptobrevin Regulates Spontaneous Fusion.” Biophysical Journal 111, 9 (November 2016): 1954–1964 © 2016 Biophysical Societyen_US
dc.contributor.departmentMassachusetts Institute of Technology. Department of Biologyen_US
dc.contributor.mitauthorVolfson, Dina
dc.contributor.mitauthorLittleton, J. Troy
dc.relation.journalBiophysical Journalen_US
dc.eprint.versionAuthor's final manuscripten_US
dc.type.urihttp://purl.org/eprint/type/JournalArticleen_US
eprint.statushttp://purl.org/eprint/status/PeerRevieweden_US
dc.date.updated2018-08-13T13:26:54Z
dspace.orderedauthorsVasin, Alexander; Volfson, Dina; Littleton, J. Troy; Bykhovskaia, Mariaen_US
dspace.embargo.termsNen_US
dc.identifier.orcidhttps://orcid.org/0000-0001-5576-2887
mit.licensePUBLISHER_CCen_US


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