Exportins (XPO) or chromosomal maintenance protein mediate the nuclear export of cellular proteins with a leucine-rich export signal (NES) and RNA. XPO is regulated by GTPaseRan. RanGTP bind to XPO forming a ternary complex with the exported protein. The complex diffuses through the nuclear core complex to the cytoplasm and then dissociates.
- XPO-1 mediates nuclear transport of cellular proteins bearing a Leu-rich nuclear export signal and of RNA[1].
- XPO-4 mediates nuclear transport of eukaryotic translation initiation factor 5A[2].
- XPO-5 mediates nuclear transport of pre-miroRNAs and short hairpin RNAs[3].
Structural highlights
Yeast exportin-5 with GTPaseRan, Mg+2 and RNA.
GTP binding site.
Mg coordination site (PDB code 3icq).[4]
3D structures of exportin
Exportin 3D structures
- ↑ Kohler A, Hurt E. Exporting RNA from the nucleus to the cytoplasm. Nat Rev Mol Cell Biol. 2007 Oct;8(10):761-73. PMID:17786152 doi:https://dx.doi.org/10.1038/nrm2255
- ↑ Lipowsky G, Bischoff FR, Schwarzmaier P, Kraft R, Kostka S, Hartmann E, Kutay U, Gorlich D. Exportin 4: a mediator of a novel nuclear export pathway in higher eukaryotes. EMBO J. 2000 Aug 15;19(16):4362-71. PMID:10944119 doi:https://dx.doi.org/10.1093/emboj/19.16.4362
- ↑ Yi R, Qin Y, Macara IG, Cullen BR. Exportin-5 mediates the nuclear export of pre-microRNAs and short hairpin RNAs. Genes Dev. 2003 Dec 15;17(24):3011-6. Epub 2003 Dec 17. PMID:14681208 doi:https://dx.doi.org/10.1101/gad.1158803
- ↑ Cook AG, Fukuhara N, Jinek M, Conti E. Structures of the tRNA export factor in the nuclear and cytosolic states. Nature. 2009 Sep 3;461(7260):60-5. PMID:19680239 doi:10.1038/nature08394
