1y2a

Structural highlights

Function

[IMA2_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. [PLS1_HUMAN] May mediate accelerated ATP-independent bidirectional transbilayer migration of phospholipids upon binding calcium ions that results in a loss of phospholipid asymmetry in the plasma membrane. May play a central role in the initiation of fibrin clot formation, in the activation of mast cells and in the recognition of apoptotic and injured cells by the reticuloendothelial system.^{[1] [2]} May play a role in the antiviral response of interferon (IFN) by amplifying and enhancing the IFN response through increased expression of select subset of potent antiviral genes. May contribute to cytokine-regulated cell proliferation and differentiation.^{[3] [4]}

Evolutionary Conservation

Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf.

See Also

• Importin

References

1. ↑ Basse F, Stout JG, Sims PJ, Wiedmer T. Isolation of an erythrocyte membrane protein that mediates Ca2+-dependent transbilayer movement of phospholipid. J Biol Chem. 1996 Jul 19;271(29):17205-10. PMID:8663431
2. ↑ Dong B, Zhou Q, Zhao J, Zhou A, Harty RN, Bose S, Banerjee A, Slee R, Guenther J, Williams BR, Wiedmer T, Sims PJ, Silverman RH. Phospholipid scramblase 1 potentiates the antiviral activity of interferon. J Virol. 2004 Sep;78(17):8983-93. PMID:15308695 doi:http://dx.doi.org/10.1128/JVI.78.17.8983-8993.2004
3. ↑ Basse F, Stout JG, Sims PJ, Wiedmer T. Isolation of an erythrocyte membrane protein that mediates Ca2+-dependent transbilayer movement of phospholipid. J Biol Chem. 1996 Jul 19;271(29):17205-10. PMID:8663431
4. ↑ Dong B, Zhou Q, Zhao J, Zhou A, Harty RN, Bose S, Banerjee A, Slee R, Guenther J, Williams BR, Wiedmer T, Sims PJ, Silverman RH. Phospholipid scramblase 1 potentiates the antiviral activity of interferon. J Virol. 2004 Sep;78(17):8983-93. PMID:15308695 doi:http://dx.doi.org/10.1128/JVI.78.17.8983-8993.2004
5. ↑ Chen MH, Ben-Efraim I, Mitrousis G, Walker-Kopp N, Sims PJ, Cingolani G. Phospholipid scramblase 1 contains a nonclassical nuclear localization signal with unique binding site in importin alpha. J Biol Chem. 2005 Mar 18;280(11):10599-606. Epub 2004 Dec 17. PMID:15611084 doi:10.1074/jbc.M413194200