Synaptotagmin II (SYT2)

Synaptotagmins, like SYT2, are integral membrane proteins of synaptic vesicles thought to serve as Ca(2+) sensors in the process of vesicular trafficking and exocytosis.Syt2 and Syt1 are 88% identical in the cytoplasmic region. RNA blots demonstrated complementary patterns of expression for Syt2 and Syt1, with Syt1 preferentially expressed in rostral brain regions and Syt2 predominantly expressed in caudal brain regions.Endogenous Wnk1 and Syt2 coimmunoprecipitated and colocalized on a subset of secretory granules in a rat insulinoma cell line. Phosphorylation by Wnk1 increased the amount of Ca(2+) required for Syt2 binding to phospholipid vesicles. phosphorylation of SYT2 by WNK1 can regulate Ca(2+) sensing and the subsequent Ca(2+)-dependent interactions mediated by synaptotagmin C2 domains.