GTP-binding protein involved in nucleocytoplasmic transport. Required for the import of protein into the nucleus and also for RNA export. Essential for cell viability. By analogy with Ras, Ran may be activated when GTP is exchanged for bound GDP by RCC1 and inactivated when GTP is hydrolyzed by Ran upon activation by RanGAP1. Found in a nuclear export complex with RanGTP, exportin and pre-miRNA (By similarity). Forms a complex with YRB1. Interacts with BUD5, CEX1, RRP12, SRM1, and DIS3/RRP44. Belongs to the small GTPase superfamily. Ran family.