2x19

Structural highlights

Function

[GSP1_YEAST] 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. [IPO13_HUMAN] Functions in nuclear protein import as nuclear transport receptor. Serves as receptor for nuclear localization signals (NLS) in cargo substrates. Is thought to mediate docking of the importin/substrate complex to the nuclear pore complex (NPC) through binding to nucleoporin and the complex is subsequently translocated through the pore by an energy requiring, Ran-dependent mechanism. At the nucleoplasmic side of the NPC, Ran binds to the importin, the importin/substrate complex dissociates and importin is re-exported from the nucleus to the cytoplasm where GTP hydrolysis releases Ran. The directionality of nuclear import is thought to be conferred by an asymmetric distribution of the GTP- and GDP-bound forms of Ran between the cytoplasm and nucleus (By similarity). Mediates the nuclear import of UBC9, the RBM8A/MAGOH complex, PAX6 and probably other members of the paired homeobox family. Also mediates nuclear export of eIF-1A, and the cytoplasmic release of eIF-1A is triggered by the loading of import substrates onto IPO13.^{[1] [2]}

Evolutionary Conservation

Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf.

See Also

• Importin

References

1. ↑ Mingot JM, Kostka S, Kraft R, Hartmann E, Gorlich D. Importin 13: a novel mediator of nuclear import and export. EMBO J. 2001 Jul 16;20(14):3685-94. PMID:11447110 doi:10.1093/emboj/20.14.3685
2. ↑ Ploski JE, Shamsher MK, Radu A. Paired-type homeodomain transcription factors are imported into the nucleus by karyopherin 13. Mol Cell Biol. 2004 Jun;24(11):4824-34. PMID:15143176 doi:10.1128/MCB.24.11.4824-4834.2004
3. ↑ Bono F, Cook AG, Grunwald M, Ebert J, Conti E. Nuclear import mechanism of the EJC component Mago-Y14 revealed by structural studies of importin 13. Mol Cell. 2010 Jan 29;37(2):211-22. PMID:20122403 doi:10.1016/j.molcel.2010.01.007