Guanine nucleotide exchange factor (GEF) which may activate RAB8A and RAB8B (, ). Promotes the exchange of GDP to GTP, converting inactive GDP-bound Rab proteins into their active GTP-bound form (, ). Mediates the release of GDP from RAB8A and RAB8B but not from RAB3A or RAB5 (, ). Modulates actin organization and promotes polarized transport of RAB8A-specific vesicles to the cell surface . Together with RAB11A, RAB8A, the exocyst complex, PARD3, PRKCI, ANXA2, CDC42 and DNMBP promotes transcytosis of PODXL to the apical membrane initiation sites (AMIS), apical surface formation and lumenogenesis . Part of the ciliary targeting complex containing Rab11, ASAP1, RAB3IP and RAB11FIP3 and ARF4 that promotes RAB3IP preciliary vesicle trafficking to mother centriole and ciliogenesis initiation (, ).
Subcellular locations: Cytoplasm, Nucleus, Cytoplasm, Cytoskeleton, Cell projection, Lamellipodium, Vesicle, Cytoplasm, Cytoskeleton, Microtubule organizing center, Centrosome
Predominantly cytoplasmic but a small proportion colocalizes with SSX2 in the nucleus. Activation of protein kinase C results in redistribution to the periphery of lamellipodia.
Expressed in brain, kidney, heart, pancreas and placenta. Not detected in skeletal muscle or liver.