synaptotagmin 13(SYT13) Homo sapiens This gene encodes a member of the large synaptotagmin protein family. Family members have an extracellular N-terminal transmembrane domain and a cytoplasmic C terminus with two tandem C2 domains (C2A and C2B). Synaptotogmin family members can form homo- and heteromeric complexes with each other. They also have different biochemical properties and developmental profiles, and patterns of tissue distribution. Synaptotagmins function as membrane traffickers in multicellular organisms. Two alternatively spliced transcript variants that encode different protein isoforms have been described for this gene. [provided by RefSeq, Oct 2011],