background:
RanGAP1, is a homodimeric 65-kD polypeptide that specifically induces the GTPase activity of RAN, but not of RAS by over 1,000-fold. RanGAP1 is the immediate antagonist of RCC1, a regulator molecule that keeps RAN in the active, GTP-bound state. The RANGAP1 gene encodes a 587-amino acid polypeptide. The sequence is unrelated to that of GTPase activators for other RAS-related proteins, but is 88% identical to Fug1, the murine homolog of yeast Rna1p. RanGAP1 and RCC1 control RAN-dependent transport between the nucleus and cytoplasm. RanGAP1 is a key regulator of the RAN GTP/GDP cycle. [provided by RefSeq, Jul 2008].
Function:
GTPase activator for the nuclear Ras-related regulatory protein Ran, converting it to the putatively inactive GDP-bound state.
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. Interacts with TRAF6.
Subcellular Location:
Cytoplasm. Nucleus membrane; Peripheral membrane protein; Cytoplasmic side. Chromosome, centromere, kinetochore. Cytoplasm, cytoskeleton, spindle pole. Note=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.
Tissue Specificity:
Highly expressed in brain, thymus and testis.
Post-translational modifications:
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.
Sumoylated with 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.
Contains 6 LRR (leucine-rich) repeats.
Database links:
UniProtKB/Swiss-Prot: P9260.1
Important Note:
This product as supplied is intended for research use only, not for use in human, therapeutic or diagnostic applications.
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