Predicted to enable GTPase activator activity; myosin II binding activity; and syntaxin binding activity. Predicted to be involved in regulation of protein secretion and regulation of synaptic vesicle exocytosis. Predicted to act upstream of or within glucose homeostasis; negative regulation of insulin secretion; and positive regulation of protein secretion. Predicted to be part of SNARE complex. Predicted to be active in neuromuscular junction; neuronal dense core vesicle; and plasma membrane. Orthologous to human STXBP5L (syntaxin binding protein 5L). [provided by Alliance of Genome Resources, Apr 2022]