Synaptotagmin-5 is a protein that in humans is encoded by the SYT5 gene. Synaptotagmins, such as SYT5, are a family of type III membrane proteins characterized by cytoplasmic repeats related to protein kinase C (see MIM 176960) regulatory (C2) domains, which are thought to bind calcium. Synaptotagmins may act both as negative regulators of vesicle fusion, allowing fusion in the presence of calcium, and as calcium receptors or sensor molecules (summary by Hudson and Birnbaum, 1995 [PubMed 7597049]).[supplied by OMIM].
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).