Enables identical protein binding activity. Involved in cellular response to brain-derived neurotrophic factor stimulus; dendrite extension; and synaptic vesicle uncoating. Acts upstream of or within regulation of receptor internalization and synaptic vesicle endocytosis. Located in early endosome and presynaptic cytosol. Is active in photoreceptor ribbon synapse. Is expressed in several structures, including adrenal gland; central nervous system; dorsal aorta; peripheral nervous system; and testis. Orthologous to human SH3GL2 (SH3 domain containing GRB2 like 2, endophilin A1). [provided by Alliance of Genome Resources, Apr 2022]