Rab-3A-interacting protein (Rab3ip)

Guanine nucleotide exchange factor (GEF) which may activate RAB8A and RAB8B. Promotes the exchange of GDP to GTP, converting inactive GDP-bound Rab proteins in their active GTP- bound form.

Mediates the release of GDP from RAB8A and RAB8B although not from RAB3A or RAB5. Modulates actin organization and promotes polarized transport of RAB8A-specific vesicles to the cell surface.