The N-terminal peptide of the syntaxin Tlg2p modulates binding of its closed conformation to Vps45p

Furgason, M.L.M., MacDonald, C., Shanks, S.G., Ryder, S.P., Bryant, N.J. and Munson, M. (2009) The N-terminal peptide of the syntaxin Tlg2p modulates binding of its closed conformation to Vps45p. Proceedings of the National Academy of Sciences of the United States of America, 106(34), pp. 14303-14308. (doi: 10.1073/pnas.0902976106) (PMID:19667197) (PMCID:PMC2732825)

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Abstract

The Sec1/Munc18 (SM) protein family regulates intracellular trafficking through interactions with individual SNARE proteins and assembled SNARE complexes. Revealing a common mechanism of this regulation has been challenging, largely because of the multiple modes of interaction observed between SM proteins and their cognate syntaxin-type SNAREs. These modes include binding of the SM to a closed conformation of syntaxin, binding to the N-terminal peptide of syntaxin, binding to assembled SNARE complexes, and/or binding to nonsyntaxin SNAREs. The SM protein Vps45p, which regulates endosomal trafficking in yeast, binds the conserved N-terminal peptide of the syntaxin Tlg2p. We used size exclusion chromatography and a quantitative fluorescent gel mobility shift assay to reveal an additional binding site that does not require the Tlg2p N-peptide. Characterization of Tlg2p mutants and truncations indicate that this binding site corresponds to a closed conformation of Tlg2p. Furthermore, the Tlg2p N-peptide competes with the closed conformation for binding, suggesting a fundamental regulatory mechanism for SM-syntaxin interactions in SNARE assembly and membrane fusion.

Item Type:Articles
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Bryant, Dr Nia and Shanks, Dr Scott
Authors: Furgason, M.L.M., MacDonald, C., Shanks, S.G., Ryder, S.P., Bryant, N.J., and Munson, M.
Subjects:Q Science > QH Natural history > QH345 Biochemistry
College/School:College of Medical Veterinary and Life Sciences > Institute of Molecular Cell and Systems Biology
Journal Name:Proceedings of the National Academy of Sciences of the United States of America
ISSN:0027-8424
ISSN (Online):1091-6490
Published Online:25 August 2009

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Project CodeAward NoProject NamePrincipal InvestigatorFunder's NameFunder RefLead Dept
342871The role of the SEC1P-like/MUNC18C protein Vps45p in SNARE complex formationNia BryantBiotechnology and Biological Sciences Research Council (BBSRC)C19548Institute of Molecular Cell and Systems Biology