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].
- XPO-t or karyopherin is a nuclear transport receptor involved in the export of tRNA to the cytoplasm[4].
Structural highlights
Yeast exportin-5 with GTPaseRan, Mg+2 and RNA.
GTP binding site.
Mg coordination site (PDB code 3icq).[5]
3D structures of exportin
Exportin 3D structures
- ↑ Caillot M, Miloudi H, Taly A, Profitós-Pelejà N, Santos JC, Ribeiro ML, Maitre E, Saule S, Roué G, Jardin F, Sola B. Exportin 1-mediated nuclear/cytoplasmic trafficking controls drug sensitivity of classical Hodgkin's lymphoma. Mol Oncol. 2023 Dec;17(12):2546-2564. PMID:36727672 doi:10.1002/1878-0261.13386
- ↑ 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
- ↑ Leisegang MS, Martin R, Ramírez AS, Bohnsack MT. Exportin t and Exportin 5: tRNA and miRNA biogenesis Biol Chem. 2012 Jul;393(7):599-604. PMID:22944664 doi:10.1515/hsz-2012-0146
- ↑ 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
