Calcineurin-mediated dephosphorylation of synaptotagmin VI is necessary for acrosomal exocytosis.

ABSTRACT: Regulated secretion is a fundamental process underlying the function of many cell types. In particular, acrosomal exocytosis in mammalian sperm is essential for egg fertilization. In general, exocytosis is initiated by a cytosolic calcium increase. In this report we show that calcium affects several factors during human sperm acrosomal exocytosis. By using an antibody that specifically recognizes synaptotagmin VI phosphorylated at the polybasic region of the C2B domain, we showed that a calcium-dependent dephosphorylation of this protein occurred at early stages of the acrosomal exocytosis in streptolysin O-permeabilized sperm. We identified the phosphatase as calcineurin and showed that the activity of this enzyme is absolutely required during the early steps of the secretory process. Whe

SUBMITTER: Castillo Bennett J 

PROVIDER: S-EPMC2924044 | biostudies-literature | 2010 Aug

REPOSITORIES: biostudies-literature