GTPase involved in nucleocytoplasmic transport, participatingboth to the import and the export from the nucleus of proteins and RNAs. Switches between acytoplasmic GDP- and a nuclear GTP-bound state by nucleotide exchangeand GTP hydrolysis. Nuclear importreceptors such as importin beta bind their substrates only in theabsence of GTP-bound RAN and release them upon direct interaction withGTP-bound RAN, while export receptors behave in the opposite way. Thereby, RAN controls cargo loading and release by transport receptorsin the proper compartment and ensures the directionality of thetransport. Interactionwith RANBP1 induces a conformation change in the complex formed by XPO1and RAN that triggers the release of the nuclear export signal of cargoproteins. RAN (GTP-bound form) triggers microtubuleassembly at mitotic chromosomes and is required for normal mitoticspindle assembly and chromosome segregation. Required for normal progress through mitosis. The complex withBIRC5/survivin plays a role in mitotic spindle formation by serving asa physical scaffold to help deliver the RAN effector molecule TPX2 tomicrotubules. Acts as a negative regulator of thekinase activity of VRK1 and VRK2. Enhances AR-mediated transactivation. Transactivation decreases as the poly-Glnlength within AR increases. [1-11]

MAAQGEPQVQFKLVLVGDGGTGKTTFVKRHLTGEFEKKYVATLGVEVHPLVFHTNRGPIKFNVWDTAGQEKFGGLRDGYYIQAQCAIIMFDVTSRVTYKNVPNWHRDLVRVCENIPIVLCGNKVDIKDRKVKAKSIVFHRKKNLQYYDISAKSNYNFEKPFLWLARKLIGDPNLEFVAMPALAPPEVVMDPALAAQYEHDLEVAQTTALPDEDDDL