SYT7 is a calcium sensor that mediates calcium-dependent exocytosis of synaptic and secretory vesicles through its C2 domains, which bind calcium and phospholipids. SYT7 binds calcium with high affinity and slower kinetics than other synaptotagmins, enabling diverse cellular functions. Beyond canonical synaptic roles, SYT7 regulates calcium-triggered lysosomal exocytosis, which is central to plasma membrane repair and contributes to phagocytosis by macrophages and bone remodeling in osteoclasts and osteoblasts. SYT7 also acts as a key mediator of synaptic facilitation—the short-term enhancement of neurotransmitter release following elevated intracellular calcium—and regulates synaptic vesicle replenishment through calmodulin binding. Additionally, SYT7 modulates insulin and glucagon secretion in pancreatic beta-cells and promotes cholesterol transport between lysosomes and peroxisomes. In disease contexts, SYT7 is dysregulated in multiple cancers. In non-small-cell lung cancer (NSCLC), elevated SYT7 expression correlates with worse prognosis and promotes tumor exosome secretion containing CEP55, driving angiogenesis and metastasis via mTOR pathway activation 1. SYT7 overexpression similarly promotes thyroid cancer progression by stabilizing HMGB3 protein levels 2. In neurodegenerative diseases, aberrant TDP-43-dependent cryptic splicing of SYT7 accumulates in Alzheimer's disease brains 3 and drives neuronal dysfunction in amyotrophic lateral sclerosis and frontotemporal dementia 4. G-quadruplex stabilization in the SYT7 promoter represents a potential therapeutic strategy to suppress tumor proliferation 5.