Structural highlights
Function
[IMA1_HUMAN] Functions in nuclear protein import as an adapter protein for nuclear receptor KPNB1. Binds specifically and directly to substrates containing either a simple or bipartite NLS motif. Docking of the importin/substrate complex to the nuclear pore complex (NPC) is mediated by KPNB1 through binding to nucleoporin FxFG repeats 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 importin-beta and the three components separate and importin-alpha and -beta are re-exported from the nucleus to the cytoplasm where GTP hydrolysis releases Ran from importin. 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. [NUP50_HUMAN] Component of the nuclear pore complex that has a direct role in nuclear protein import. Actively displaces NLSs from importin-alpha, and facilitates disassembly of the importin-alpha:beta-cargo complex and importin recycling. Interacts with multiple transport receptor proteins including CDKN1B. This interaction is required for correct intracellular transport and degradation of CDKN1B.[1]
See Also
References
- ↑ Ogawa Y, Miyamoto Y, Asally M, Oka M, Yasuda Y, Yoneda Y. Two isoforms of Npap60 (Nup50) differentially regulate nuclear protein import. Mol Biol Cell. 2010 Feb 15;21(4):630-8. doi: 10.1091/mbc.E09-05-0374. Epub 2009, Dec 16. PMID:20016008 doi:http://dx.doi.org/10.1091/mbc.E09-05-0374
