Biochemistry & Molecular Pharmacology
Department of Biochemistry and Molecular Pharmacology
Biochemistry | Molecular Biology | Structural Biology
Trafficking of protein and lipid cargo through the secretory pathway in eukaryotic cells is mediated by membrane-bound vesicles. Secretory vesicle targeting and fusion require a conserved multisubunit protein complex termed the exocyst, which has been implicated in specific tethering of vesicles to sites of polarized exocytosis. The exocyst is directly involved in regulating soluble N-ethylmaleimide-sensitive factor (NSF) attachment protein receptor (SNARE) complexes and membrane fusion through interactions between the Sec6 subunit and the plasma membrane SNARE protein Sec9. Here we show another facet of Sec6 function-it directly binds Sec1, another SNARE regulator, but of the Sec1/Munc18 family. The Sec6-Sec1 interaction is exclusive of Sec6-Sec9 but compatible with Sec6-exocyst assembly. In contrast, the Sec6-exocyst interaction is incompatible with Sec6-Sec9. Therefore, upon vesicle arrival, Sec6 is proposed to release Sec9 in favor of Sec6-exocyst assembly and to simultaneously recruit Sec1 to sites of secretion for coordinated SNARE complex formation and membrane fusion.
exocyst, membrane trafficking
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Copyright © 2012 Morgera et al. This article is distributed by The American Society for Cell Biology under license from the author(s). Two months after publication it is available to the public under an Attribution–Noncommercial–Share Alike 3.0 Unported Creative Commons License (http://creativecommons.org/licenses/by-nc-sa/3.0).
DOI of Published Version
Mol Biol Cell. 2012 Jan;23(2):337-46. doi: 10.1091/mbc.E11-08-0670. Epub 2011 Nov 23. Link to article on publisher's site
Molecular biology of the cell
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This work is licensed under a Creative Commons Attribution-Noncommercial-Share Alike 4.0 License.
Morgera, Francesca; Sallah, Margaret R.; Dubuke, Michelle L.; Gandhi, Pallavi; Brewer, Daniel N.; Carr, Chavela M.; and Munson, Mary, "Regulation of exocytosis by the exocyst subunit Sec6 and the SM protein Sec1" (2012). GSBS Student Publications. 2023.