Enables syntaxin binding activity. Acts upstream of or within several processes, including cellular response to interferon-gamma; negative regulation of glucose import; and secretion by cell. Located in apical plasma membrane; cytosol; and phagocytic vesicle. Is expressed in embryo. Orthologous to human STXBP3 (syntaxin binding protein 3). [provided by Alliance of Genome Resources, Apr 2022]