Defects in Synaptic Vesicle Docking in Unc-18 Mutants

Overview

Journal Nat Neurosci

Date 2003 Sep 16

PMID 12973353

Citations 131

Authors

Robby M Weimer

Janet E Richmond

Warren S Davis

Gayla Hadwiger

Michael L Nonet

Erik M Jorgensen

Affiliations

Soon will be listed here.

Abstract

Sec1-related proteins function in most, if not all, membrane trafficking pathways in eukaryotic cells. The Sec1-related protein required in neurons for synaptic vesicle exocytosis is UNC-18. Several models for UNC-18 function during vesicle exocytosis are under consideration. We have tested these models by characterizing unc-18 mutants of the nematode Caenorhabditis elegans. In the absence of UNC-18, the size of the readily releasable pool is severely reduced. Our results show that the near absence of fusion-competent vesicles is not caused by a reduction in syntaxin levels, by a mislocalization of syntaxin, by a defect in fusion or by a failure to open syntaxin during priming. Rather, we found a reduction of docked vesicles at the active zone in unc-18 mutants, suggesting that UNC-18 functions, directly or indirectly, as a facilitator of vesicle docking.

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