This gene encodes a member of an ADP-ribosylation factor GTPase-activating protein family involved in membrane trafficking and cytoskeleton dynamics. This gene functions as a direct regulator of the adaptor-related protein complex 3 on endosomes. Multiple transcript variants encoding different isoforms have been found for this gene. GTPase-activating protein for ARF1 and, to a lesser extent, ARF5. Directly and specifically regulates the adapter protein 3 (AP-3)-dependent trafficking of proteins in the endosomal-lysosomal system.