GTP-binding protein involved in nucleocytoplasmic transport. Required for the import of protein into the nucleus and also for RNA export. Involved in chromatin condensation and control of cell cycle (By similarity). Found in a nuclear export complex with RanGTP, exportin and pre-miRNA (By similarity). Interacts with RANBP1A and RANBP1B (PubMed:9025305). Interacts with TRN1 (PubMed:14756317). Interacts with ATX1 (PubMed:17223078). Interacts with KPNB1 (PubMed:23582042). Binds to XPO1 (PubMed:10652141). Interacts with MOS14 (PubMed:21738492). Binds to NTF2B (PubMed:16428596). Regulated by light. Belongs to the small GTPase superfamily. Ran family.