Sequential analysis of trans-SNARE formation in intracellular membrane fusion.

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Version: author
Serval ID
serval:BIB_4C9C2AB141A9
Type
Article: article from journal or magazin.
Collection
Publications
Institution
Title
Sequential analysis of trans-SNARE formation in intracellular membrane fusion.
Journal
PLoS Biology
Author(s)
Alpadi K., Kulkarni A., Comte V., Reinhardt M., Schmidt A., Namjoshi S., Mayer A., Peters C.
ISSN
1545-7885 (Electronic)
ISSN-L
1544-9173
Publication state
Published
Issued date
2012
Volume
10
Number
1
Pages
e1001243
Language
english
Abstract
SNARE complexes are required for membrane fusion in the endomembrane system. They contain coiled-coil bundles of four helices, three (Q(a), Q(b), and Q(c)) from target (t)-SNAREs and one (R) from the vesicular (v)-SNARE. NSF/Sec18 disrupts these cis-SNARE complexes, allowing reassembly of their subunits into trans-SNARE complexes and subsequent fusion. Studying these reactions in native yeast vacuoles, we found that NSF/Sec18 activates the vacuolar cis-SNARE complex by selectively displacing the vacuolar Q(a) SNARE, leaving behind a Q(bc)R subcomplex. This subcomplex serves as an acceptor for a Q(a) SNARE from the opposite membrane, leading to Q(a)-Q(bc)R trans-complexes. Activity tests of vacuoles with diagnostic distributions of inactivating mutations over the two fusion partners confirm that this distribution accounts for a major share of the fusion activity. The persistence of the Q(bc)R cis-complex and the formation of the Q(a)-Q(bc)R trans-complex are both sensitive to the Rab-GTPase inhibitor, GDI, and to mutations in the vacuolar tether complex, HOPS (HOmotypic fusion and vacuolar Protein Sorting complex). This suggests that the vacuolar Rab-GTPase, Ypt7, and HOPS restrict cis-SNARE disassembly and thereby bias trans-SNARE assembly into a preferred topology.
Keywords
Alleles, Intracellular Membranes/metabolism, Kinetics, Membrane Fusion, Models, Biological, Multiprotein Complexes/metabolism, Mutation/genetics, Oxidation-Reduction, Protein Binding, Protein Stability, SNARE Proteins/metabolism, Saccharomyces cerevisiae/metabolism, Saccharomyces cerevisiae Proteins/metabolism, Vacuoles/metabolism, rab GTP-Binding Proteins/metabolism
Pubmed
Web of science
Open Access
Yes
Create date
07/12/2012 10:23
Last modification date
20/08/2019 14:01
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