GTP-binding protein that functions in embryogenesis, cytokinesis, germline development and microtubulule cytoskeleton dynamics. Some diffuse cytoplasmic expression is detected but expression is concentrated mainly next to centrosomes and is excluded from the mitotic spindle area. Localizes to the cortical plasma membrane of embryonic blastomeres. In the embryo, strongly expressed in migrating hypodermal cells. Shortly before the beginning of elongation, expressed in many developing neurons where it persists throughout adulthood. In the larva, highly expressed in migrating hypodermal cells and the uterus. Also expressed in vulva, spermatheca, sheath cells, distal tips cells and proctoderm of the male tail. Expression is first detected during embryogenesis at the beginning of morphogenesis and continues in a subset of larval tissues and in adult neurons. Worms exhibit abnormal vulva, gonad and male tail development and disruption in embryonic proliferation. Subcellular defects include a lack of microtubule cytoskeleton and excessive chromosomes in oocyte nuclei. Many embryos show a lethal phenotype arrested at the bean stage just prior to the beginning of morphogenesis. Belongs to the small GTPase superfamily. Arf family.