Function:GTPase activator for the nuclear Ras-related regulatory protein Ran, converting it to the putatively inactive GDP-bound state.,PTM:Phosphorylated occurs before nuclear envelope breakdown and continues throughout mitosis. Phosphorylated by the M-phase kinase cyclin B/Cdk1, in vitro. Differential timimg of dephosphorylation occurs during phases of mitosis. The phosphorylated form remains associated with RANBP2/NUP358 and the SUMO E2-conjugating enzyme, UBC9, on nuclear pore complex (NPC) diassembly and during mitosis.,PTM:Sumoylated by SUMO1. Sumoylation is necessary for targeting to the nuclear envelope (NE), and for association with mitotic spindles and kinetochores during mitosis. Also required for interaction with RANBP2 and is mediated by UBC9.,similarity:Belongs to the RNA1 family.,similarity:Contains 6 LRR (leucine-rich) repeats.,subcellular location:Cytoplasmic during interphase. Targeted to the nuclear rim after sumoylation. During mitosis, associates with mitotic spindles. Association with kinetochores appears soon after nuclear envelope breakdown and persists until late anaphase. Mitotic location also requires sumoylation.,subunit:Homodimer. Forms a tight complex in association with RANBP2/NUP358 and UBE2I/UBC9, the ubiquitin-conjugating enzyme E2. Interacts with UBE2I; the interaction conjugates SUMO1 to RANGAP1, and subsequently stabilizes interactions of sumoylated RANGAP1 with RANBP2/NUP358. The SUMO1/RANGAP1/UBC9/NUP358 complex associates with nuclear pore complexes.,tissue specificity:Highly expressed in brain, thymus and testis.,
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