Predicted to enable GDP binding activity; GTP-dependent protein binding activity; and GTPase activity. Predicted to be involved in several processes, including intracellular protein transport; plasma membrane to endosome transport; and regulation of endocytosis. Predicted to act upstream of or within endosome organization. Is anchored component of synaptic vesicle membrane. Orthologous to human RAB5B (RAB5B, member RAS oncogene family). [provided by Alliance of Genome Resources, Apr 2022]