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PMID: 22114349 Published · ppublish English Journal Article Research Support, N.I.H., Extramural

Regulation of exocytosis by the exocyst subunit Sec6 and the SM protein Sec1.

Molecular biology of the cell ·Vol. 23 ·No. 2 ·2012-01-00 ·Pages 337-46

Morgera F, Sallah MR, Dubuke ML, Gandhi P, Brewer DN, Carr CM, Munson M

Abstract

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.

MeSH Terms
Exocytosis Membrane Fusion Munc18 Proteins/metabolism Protein Subunits/metabolism Qc-SNARE Proteins/metabolism SNARE Proteins/metabolism Saccharomyces cerevisiae/metabolism,physiology Saccharomyces cerevisiae Proteins/metabolism Vesicular Transport Proteins/metabolism
Chemicals
Munc18 Proteins Protein Subunits Qc-SNARE Proteins SEC1 protein, S cerevisiae SEC6 protein, S cerevisiae SEC9 protein, S cerevisiae SNARE Proteins Saccharomyces cerevisiae Proteins Vesicular Transport Proteins
Authors & Affiliations
7 authors, click to expand affiliations / ORCID
Morgera Francesca
Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, MA 01605, USA.
Sallah Margaret R
Dubuke Michelle L
Gandhi Pallavi
Brewer Daniel N
Carr Chavela M
Munson Mary
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Article Info
Journal
Molecular biology of the cell
Abbr.
Mol Biol Cell
ISSN
1939-4586
DOI
10.1091/mbc.E11-08-0670
Published
2012-01-00
Epub
2011-00-23
Pages
337-46
Language
English
Region
United States
NLM ID
9201390
PMCID
PMC3258177
Subset
IM
Grants
NIGMS NIH HHS · R01 GM068803 · United States
NIGMS NIH HHS · GM068803 · United States
External Links
PubMed source DOI: 10.1091/mbc.E11-08-0670 PMC Full Text View journal details
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