Predicted to enable calmodulin binding activity. Predicted to act upstream of or within binding activity of sperm to zona pellucida. Located in cytoplasm; external side of plasma membrane; and sperm flagellum. Is expressed in several structures, including brain; gonad; heart; hemolymphoid system gland; and lung. Orthologous to human SPA17 (sperm autoantigenic protein 17). [provided by Alliance of Genome Resources, Apr 2022]