Synaptotagmin XVI (SYT16)

By searching databases for sequences encoding synaptotagmin-like C2 domains, Fukuda (2003) identified mouse and human SYT14 and SYT16, which they called STREP14. The deduced mouse and human STREP14 proteins contain 639 and 625 amino acids, respectively. Both have C-terminal C-type tandem C2 domains, but they lack the N-terminal transmembrane domain found in other synaptotagmins. RT-PCR detected highest Strep14 expression in mouse heart and testis, with weaker expression in kidney and lung. In mouse embryos, expression was weak on day 7 and strong on days 11, 15, and 17. mouse Strep14 showed relatively weak homooligomerization and heterooligomerization with Syt14, irrespective of the presence of Ca(2+). The C2 domains of Strep14 bound liposomes made up of phosphatidylcholine and phosphatidylserine.