Synaptotagmin XV (SYT15)

SYT15 belongs to the synaptotagmin family of membrane trafficking proteins. Synaptotagmins contain a short extracellular domain, a single N-terminal transmembrane domain, and tandem C2 domains that can bind several Ca(2+) ions.The 421-amino acid isoform, designated SYT15a, contains a short N-terminal transmembrane region followed by putative fatty-acylation sites and 2 tandem C-terminal C2 domains. The 390-amino acid isoform, designated SYT15b, lacks the C-terminal portion of the second C2 domain. SYT15a shares about 79% identity with mouse Syt15a. RT-PCR of several mouse tissues revealed expression of both variants in heart, lung, skeletal muscle, and testis, as well as in 7-day embryos. Unlike several other synaptotagmins, expression of Syt15 was nearly absent in mouse brain.