ARL4D is a developmentally regulated member of the ADP-ribosylation factor/ARF-like protein （ARF/ARL） family of Ras-related GTPases. Small GTP-binding protein which cycles between an inactive GDP-bound and an active GTP-bound form， and the rate of cycling is regulated by guanine nucleotide exchange factors （GEF） and GTPase-activating proteins （GAP）. ARL4D takes part in membrane-associated intracellular trafficking. Mutations in this gene is linked to Bardet-Biedl syndrome （BBS）.
