Enables SH3 domain binding activity; protein kinase binding activity; and small GTPase binding activity. Involved in long-term synaptic potentiation; positive regulation of inhibitory postsynaptic potential; and positive regulation of synaptic vesicle priming. Located in presynaptic membrane. Is active in glutamatergic synapse and presynaptic active zone cytoplasmic component. Human ortholog(s) of this gene implicated in cone-rod dystrophy 7. Orthologous to human RIMS1 (regulating synaptic membrane exocytosis 1). [provided by Alliance of Genome Resources, Apr 2022]