Cardiff University | Prifysgol Caerdydd ORCA
Online Research @ Cardiff 
WelshClear Cookie - decide language by browser settings

Binding of UNC-18 to the N-terminus of syntaxin is essential for neurotransmission in Caenorhabditis elegans

Johnson, James R., Ferdek, Pawel, Lian, Lu-Yun, Barclay, Jeff W., Burgoyne, Robert D. and Morgan, Alan 2009. Binding of UNC-18 to the N-terminus of syntaxin is essential for neurotransmission in Caenorhabditis elegans. Biochemical Journal 418 (1) , pp. 73-80. 10.1042/BJ20081956

Full text not available from this repository.

Abstract

SNAREs (soluble N-ethylmaleimide-sensitive fusion protein-attachment protein receptors) are widely accepted to drive all intracellular membrane fusion events. SM (Sec1/Munc18-like) proteins bind to SNAREs and this interaction may underlie their ubiquitous requirement for efficient membrane fusion. SM proteins bind to SNAREs in at least three modes: (i) to a closed conformation of syntaxin; (ii) to the syntaxin N-terminus; and (iii) to the assembled SNARE complex. Munc18-1 exhibits all three binding modes and recent in vitro reconstitution assays suggest that its interaction with the syntaxin N-terminus is essential for neuronal SNARE complex binding and efficient membrane fusion. To investigate the physiological relevance of these binding modes, we studied the UNC-18/UNC-64 SM/SNARE pair, which is essential for neuronal exocytosis in Caenorhabditis elegans. Mutations in the N-terminus of UNC-64 strongly inhibited binding to UNC-18, as did mutations targeting closed conformation binding. Complementary mutations in UNC-18 designed to selectively impair binding to either closed syntaxin or its N-terminus produced a similarly strong inhibition of UNC-64 binding. Therefore high-affinity UNC18/UNC-64 interaction in vitro involves both binding modes. To determine the physiological relevance of each mode, unc-18-null mutant worms were transformed with wild-type or mutant unc-18 constructs. The UNC-18(R39C) construct, that is defective in closed syntaxin binding, fully rescued the locomotion defects of the unc-18 mutant. In contrast, the UNC-18(F113R) construct, that is defective in binding to the N-terminus of UNC-64, provided no rescue. These results suggest that binding of UNC-18 to closed syntaxin is dispensable for membrane fusion, whereas interaction with the syntaxin N-terminus is essential for neuronal exocytosis in vivo.

Item Type: Article
Date Type: Publication
Status: Published
Schools: Biosciences
Publisher: Biochemical Society
ISSN: 0264-6021
Last Modified: 12 Jun 2019 02:41
URI: http://orca-mwe.cf.ac.uk/id/eprint/66076

Citation Data

Cited 58 times in Google Scholar. View in Google Scholar

Cited 45 times in Scopus. View in Scopus. Powered By Scopus® Data

Actions (repository staff only)

Edit Item Edit Item