Structural highlights
Function
[IMA1_MOUSE] 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. [NIT2_NEUCR] Major nitrogen regulatory protein. During conditions of nitrogen limitation it turns on the expression of genes for enzymes which are required for the use of a variety of secondary nitrogen sources, including nitrates, purines, amino acids, and proteins.[1]
References
- ↑ Xiao X, Fu YH, Marzluf GA. The negative-acting NMR regulatory protein of Neurospora crassa binds to and inhibits the DNA-binding activity of the positive-acting nitrogen regulatory protein NIT2. Biochemistry. 1995 Jul 11;34(27):8861-8. doi: 10.1021/bi00027a038. PMID:7612627 doi:http://dx.doi.org/10.1021/bi00027a038