Enables several functions, including phosphatidylserine binding activity; protein dimerization activity; and syntaxin binding activity. Involved in several processes, including dense core granule cytoskeletal transport; negative regulation of transport; and vesicle organization. Located in several cellular components, including astrocyte projection; neuronal cell body; and secretory vesicle. Is intrinsic component of neuronal dense core vesicle membrane. Biomarker of visual epilepsy. Orthologous to human SYT4 (synaptotagmin 4). [provided by Alliance of Genome Resources, Apr 2022]