Enables protein C-terminus binding activity. Involved in negative regulation of clathrin-dependent endocytosis and positive regulation of neuron differentiation. Located in acrosomal vesicle; early endosome; and presynapse. Is active in glutamatergic synapse; postsynaptic density, intracellular component; and postsynaptic endosome. Orthologous to human SH3GL3 (SH3 domain containing GRB2 like 3, endophilin A3). [provided by Alliance of Genome Resources, Apr 2022]