Enables small GTPase binding activity. Predicted to be involved in Golgi to lysosome transport; early endosome to Golgi transport; and regulation of Golgi organization. Predicted to act upstream of or within protein transport. Predicted to be located in intracellular membrane-bounded organelle. Is expressed in central nervous system; genitourinary system; and retina outer nuclear layer. Orthologous to human RBSN (rabenosyn, RAB effector). [provided by Alliance of Genome Resources, Apr 2022]