InterPro domain: IPR045050

This entry represents a group of plant synaptotagmins and related proteins. In Arabodopsis, there are five members, SYT1-5. Structurally, they have a short uncleaved N-terminal signal peptide that overlaps a transmembrane (TM) domain, followed by a cytosolic variable region and two C-terminal C2 domains, C2A and C2B. Whereas C2A and C2B each bind phospholipids in a Ca2+-dependent manner, fold independently and act synergistically, C2B is essential for activity [ 1 ]. Arabidopsis SYT1, also known as SYTA, plays an important role in maintaining plasma membrane integrity during freezing and osmotic stresses [ 2 , 3 ]. It also serves as a virus movement protein that transports its cargos to plasmodesmata for cell-to-cell spread via an endocytic recycling pathway [ 4 ].

1. How does synaptotagmin trigger neurotransmitter release? Annu Rev Biochem 77, 615-41
2. Arabidopsis synaptotagmin1 maintains plasma membrane integrity. Plant Cell 20, 3182
3. Calcium-dependent freezing tolerance in Arabidopsis involves membrane resealing via synaptotagmin SYT1. Plant Cell 20, 3389-404
4. Arabidopsis synaptotagmin SYTA regulates endocytosis and virus movement protein cell-to-cell transport. Proc Natl Acad Sci U S A 107, 2491-6