6xu2

Structural highlights

Function

IPO5_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 ribosomal proteins RPL23A, RPS7 and RPL5. Binds to a beta-like import receptor binding (BIB) domain of RPL23A. In vitro, mediates nuclear import of H2A, H2B, H3 and H4 histones. Binds to CPEB3 and mediates its nuclear import following neuronal stimulation (By similarity). In case of HIV-1 infection, binds and mediates the nuclear import of HIV-1 Rev.[UniProtKB:Q8BKC5]^[1]

See Also

• Importin 3D structures

References

1. ↑ Jakel S, Gorlich D. Importin beta, transportin, RanBP5 and RanBP7 mediate nuclear import of ribosomal proteins in mammalian cells. EMBO J. 1998 Aug 3;17(15):4491-502. PMID:9687515 doi:10.1093/emboj/17.15.4491
2. ↑ Swale C, Da Costa B, Sedano L, Garzoni F, McCarthy AA, Berger I, Bieniossek C, Ruigrok RWH, Delmas B, Crepin T. X-ray Structure of the Human Karyopherin RanBP5, an Essential Factor for Influenza Polymerase Nuclear Trafficking. J Mol Biol. 2020 Mar 25. pii: S0022-2836(20)30254-0. doi:, 10.1016/j.jmb.2020.03.021. PMID:32222384 doi:http://dx.doi.org/10.1016/j.jmb.2020.03.021