Ca (2+) sensor involved in Ca (2+) -dependent exocytosis of secretory and synaptic vesicles through Ca (2+) and phospholipid binding to the C2 domain (By similarity) . Ca (2+) induces binding of the C2-domains to phospholipid membranes and to assembled SNARE-complexes; both actions contribute to triggering exocytosis (By similarity) . SYT7 binds Ca (2+) with high affinity and slow kinetics compared to other synaptotagmins (By similarity) . Involved in Ca (2+) -triggered lysosomal exocytosis, a major component of the plasma membrane repair (PubMed:11342594) . Ca (2+) - regulated delivery of lysosomal membranes to the cell surface is also involved in the phagocytic uptake of particles by macrophages (By similarity) . Ca (2+) -triggered lysosomal exocytosis also plays a role in bone remodeling by regulating secretory pathways in osteoclasts and osteoblasts (By similarity) . In case of infection, involved in participates cell invasion by Trypanosoma cruzi via Ca (2+) -triggered lysosomal exocytosis (PubMed:11342594, PubMed:15811535) . Involved in cholesterol transport from lysosome to peroxisome by promoting membrane contacts between lysosomes and peroxisomes: probably acts by promoting vesicle fusion by binding phosphatidylinositol-4,5-bisphosphate on peroxisomal membranes (By similarity) . Acts as a key mediator of synaptic facilitation, a process also named short-term synaptic potentiation: synaptic facilitation takes place at synapses with a low initial release probability and is caused by influx of Ca (2+) into the axon terminal after spike generation, increasing the release probability of neurotransmitters (By similarity) . Probably mediates synaptic facilitation by directly increasing the probability of release (By similarity) . May also contribute to synaptic facilitation by regulating synaptic vesicle replenishment, a process required to ensure that synaptic vesicles are ready for the arrival of the next action potential: SYT7 is required for synaptic vesicle replenishment by acting as a sensor for Ca (2+) and by forming a complex with calmodulin (By similarity) . Also acts as a regulator of Ca (2+) -dependent insulin and glucagon secretion in beta-cells (By similarity) . Triggers exocytosis by promoting fusion pore opening and fusion pore expansion in chromaffin cells (By similarity) . Also regulates the secretion of some non-synaptic secretory granules of specialized cells (By similarity) .
