GTP-binding nuclear protein Ran, Androgen receptor-associated protein 24, GTPase Ran, Ras-like protein TC4, Ras-related nuclear protein, RAN, ARA24
RAN (ras-related nuclear protein) is a small GTP bindingprotein belonging to the RAS superfamily that is essential for thetranslocation of RNA and proteins through the nuclear pore complex.The RAN protein is also involved in control of DNA synthesis andcell cycle progression. Nuclear localization of RAN requires thepresence of regulator of chromosome condensation 1 (RCC1).Mutations in RAN disrupt DNA synthesis. Because of its manyfunctions, it is likely that RAN interacts with several otherproteins. RAN regulates formation and organization of themicrotubule network independently of its role in thenucleus-cytosol exchange of macromolecules. RAN could be a keysignaling molecule regulating microtubule polymerization duringmitosis. RCC1 generates a high local concentration of RAN-GTParound chromatin which, in turn, induces the local nucleation ofmicrotubules. RAN is an androgen receptor (AR) coactivator thatbinds differentially with different lengths of polyglutamine withinthe androgen receptor. Polyglutamine repeat expansion in the AR islinked to Kennedys disease (X-linked spinal and bulbar muscularatrophy). RAN coactivation of the AR diminishes with polyglutamineexpansion within the AR, and this weak coactivation may lead topartial androgen insensitivity during the development of Kennedysdisease.