Document Detail


Ca(2+)-synaptotagmin directly regulates t-SNARE function during reconstituted membrane fusion.
MedLine Citation:
PMID:  16565726     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
In nerve terminals, exocytosis is mediated by SNARE proteins and regulated by Ca(2+) and synaptotagmin-1 (syt). Ca(2+) promotes the interaction of syt with anionic phospholipids and the target membrane SNAREs (t-SNAREs) SNAP-25 and syntaxin. Here, we have used a defined reconstituted fusion assay to determine directly whether syt-t-SNARE interactions couple Ca(2+) to membrane fusion by comparing the effects of Ca(2+)-syt on neuronal (SNAP-25, syntaxin and synaptobrevin) and yeast (Sso1p, Sec9c and Snc2p) SNAREs. Ca(2+)-syt aggregated neuronal and yeast SNARE liposomes to similar extents via interactions with anionic phospholipids. However, Ca(2+)-syt was able to bind and stimulate fusion mediated by only neuronal SNAREs and had no effect on yeast SNAREs. Thus, Ca(2+)-syt regulates fusion through direct interactions with t-SNAREs and not solely through aggregation of vesicles. Ca(2+)-syt drove assembly of SNAP-25 onto membrane-embedded syntaxin, providing direct evidence that Ca(2+)-syt alters t-SNARE structure.
Authors:
Akhil Bhalla; Michael C Chicka; Ward C Tucker; Edwin R Chapman
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Publication Detail:
Type:  In Vitro; Journal Article; Research Support, N.I.H., Extramural; Research Support, Non-U.S. Gov't     Date:  2006-03-26
Journal Detail:
Title:  Nature structural & molecular biology     Volume:  13     ISSN:  1545-9993     ISO Abbreviation:  Nat. Struct. Mol. Biol.     Publication Date:  2006 Apr 
Date Detail:
Created Date:  2006-05-22     Completed Date:  2006-06-15     Revised Date:  2007-11-14    
Medline Journal Info:
Nlm Unique ID:  101186374     Medline TA:  Nat Struct Mol Biol     Country:  United States    
Other Details:
Languages:  eng     Pagination:  323-30     Citation Subset:  IM    
Affiliation:
Howard Hughes Medical Institute, University of Wisconsin, 1300 University Avenue, SMI 129, Madison, Wisconsin, USA.
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MeSH Terms
Descriptor/Qualifier:
Animals
Calcium / metabolism*
Exocytosis
Fungal Proteins / genetics,  metabolism
Liposomes
Membrane Fusion / physiology*
Models, Biological
Mutagenesis, Site-Directed
Nerve Endings / metabolism
Rats
Recombinant Proteins / genetics,  metabolism
SNARE Proteins / genetics,  metabolism*
Synaptosomal-Associated Protein 25 / genetics,  metabolism
Synaptotagmin I / genetics,  metabolism*
Grant Support
ID/Acronym/Agency:
GM 56827/GM/NIGMS NIH HHS; MH61876/MH/NIMH NIH HHS
Chemical
Reg. No./Substance:
0/Fungal Proteins; 0/Liposomes; 0/Recombinant Proteins; 0/SNARE Proteins; 0/Synaptosomal-Associated Protein 25; 0/Synaptotagmin I; 0/Syt1 protein, rat; 7440-70-2/Calcium
Comments/Corrections
Comment In:
Nat Struct Mol Biol. 2006 Apr;13(4):301-3   [PMID:  16715046 ]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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