Adaptor protein comple, Xenopus/Amphibian, 3 (AP-3) is a heterotetramer composed of two large adaptins (delta-type subunit AP3D1 and beta-type subunit AP3B1 or AP3B2), a medium adaptin (mu-type subunit AP3M1 or AP3M2) and a small adaptin (sigma-type subunit APS1 or AP3S2). The comple, Xenopus/Amphibian, is associated with the Golgi region as well as more peripheral structures. AP-3 facilitates the budding of vesicles from the Golgi membrane and may be directly involved in trafficking to lysosomes.