Phosphatidylinositol 4,5 Bisphosphate Controls the cis and trans Interactions of Synaptotagmin 1.

ABSTRACT: Synaptotagmin 1 acts as the Ca²⁺ sensor for synchronous neurotransmitter release; however, the mechanism by which it functions is not understood and is presently a topic of considerable interest. Here, we describe measurements on full-length membrane-reconstituted synaptotagmin 1 using site-directed spin labeling in which we characterize the linker region as well as the cis (vesicle membrane) and trans (cytoplasmic membrane) binding of its two C2 domains. In the full-length protein, the C2A domain does not undergo membrane insertion in the absence of Ca²⁺; however, the C2B domain will bind to and penetrate in trans to a membrane containing phosphatidylinositol 4,5 bisphosphate, even if phosphatidylserine (PS) is present in the cis membrane. In the presence of Ca²

SUBMITTER: Nyenhuis SB 

PROVIDER: S-EPMC6701194 | biostudies-literature | 2019 Jul

REPOSITORIES: biostudies-literature