SYT10 (synaptotagmin 10) is a vesicular Ca2+ sensor protein that functions as a calcium-dependent regulator of secretory vesicle exocytosis in neurons. The protein operates through Ca2+ and phospholipid binding via its C2 domain, which enables membrane insertion and SNARE complex assembly interactions that trigger exocytosis 1. While SYT10 expression is restricted primarily to pancreas, lung, and kidney in non-neuronal tissues 2, it plays specialized roles in the nervous system beyond canonical synaptic vesicle dynamics. SYT10 has emerged as a key neuroprotective effector downstream of the transcription factor NPAS4, functioning in the neuronal response to pathophysiologic synaptic activity. Following excitotoxic insults such as kainic acid exposure, NPAS4-mediated upregulation of SYT10 expression protects hippocampal neurons against excitotoxic cell death 3. This neuroprotective pathway highlights an unexpected function beyond exocytosis regulation. Genetically, SYT10 variants associate with multiple neurological and cardiac conditions. A significant gene-gene interaction between LRRK2 and SYT10 promoter SNP rs1007709 influences Parkinson's disease risk and age-at-onset in LRRK2 mutation carriers 1. Additionally, SYT10 variants contribute to sick sinus syndrome susceptibility and heart rate response to exercise, with SYT10 categorized among genes affecting neuronal lifespan and cardiac function [PMID:34195885; 40]. Recent bioinformatic evidence suggests potential involvement in T cell activation 5.