Sequential analysis of trans-SNARE formation in intracellular membrane fusion.
| Title: | Sequential analysis of trans-SNARE formation in intracellular membrane fusion. |
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| Authors: | Kannan Alpadi, Aditya Kulkarni, Veronique Comte, Monique Reinhardt, Andrea Schmidt, Sarita Namjoshi, Andreas Mayer, Christopher Peters |
| Source: | PLoS Biology, Vol 10, Iss 1, p e1001243 (2012) |
| Publisher Information: | Public Library of Science (PLoS), 2012. |
| Publication Year: | 2012 |
| Collection: | LCC:Biology (General) |
| Subject Terms: | Biology (General), QH301-705.5 |
| More Details: | 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. |
| Document Type: | article |
| File Description: | electronic resource |
| Language: | English |
| ISSN: | 1544-9173 1545-7885 |
| Relation: | http://europepmc.org/articles/PMC3260307?pdf=render; https://doaj.org/toc/1544-9173; https://doaj.org/toc/1545-7885 |
| DOI: | 10.1371/journal.pbio.1001243 |
| Access URL: | https://doaj.org/article/18fdd1ed4a0c49feb5d28d9db1a712a6 |
| Accession Number: | edsdoj.18fdd1ed4a0c49feb5d28d9db1a712a6 |
| Database: | Directory of Open Access Journals |
| ISSN: | 15449173 15457885 |
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| DOI: | 10.1371/journal.pbio.1001243 |
| Published in: | PLoS Biology |
| Language: | English |