May be involved in Ca(2+)-dependent exocytosis of secretory vesicles through Ca(2+) and phospholipid binding to the C2 domain or may serve as Ca(2+) sensors in the process of vesicular trafficking and exocytosis. Regulates the Ca(2+)-dependent secretion of norepinephrine in PC12 cells. Required for export from the endocytic recycling compartment to the cell surface (By similarity). Binds 3 Ca(2+) ions per subunit. The ions are bound to the C2 domains. Homodimer (By similarity). Interacts with both alpha- and beta-tubulin (By similarity). In mast cells, localizes to the endocytic recycling compartment. Belongs to the synaptotagmin family.