C2B polylysine motif of synaptotagmin facilitates a Ca2+-independent stage of synaptic vesicle priming in vivo.

ABSTRACT: Synaptotagmin I, a synaptic vesicle protein required for efficient synaptic transmission, contains a highly conserved polylysine motif necessary for function. Using Drosophila, we examined in which step of the synaptic vesicle cycle this motif functions. Polylysine motif mutants exhibited an apparent decreased Ca2+ affinity of release, and, at low Ca2+, an increased failure rate, increased facilitation, and increased augmentation, indicative of a decreased release probability. Disruption of Ca2+ binding, however, cannot account for all of the deficits in the mutants; rather, the decreased release probability is probably due to a disruption in the coupling of synaptotagmin to the release machinery. Mutants exhibited a major slowing of recovery from synaptic depression, which suggests that m

SUBMITTER: Loewen CA 

PROVIDER: S-EPMC1679685 | biostudies-literature | 2006 Dec

REPOSITORIES: biostudies-literature