Enables GTPase activity and guanyl nucleotide binding activity. Acts upstream of or within endocytosis. Located in several cellular components, including cytoplasmic vesicle; membrane raft; and ruffle. Is expressed in several structures, including brain; cardiovascular system; eye; genitourinary system; and gut. Orthologous to human RAB5A (RAB5A, member RAS oncogene family). [provided by Alliance of Genome Resources, Apr 2022]