4u2x

Structural highlights

Function

[VP24_EBOZM] Prevents the establishment of cellular antiviral state by blocking the interferon-alpha/beta (IFN-alpha/beta) and IFN-gamma signaling pathways. Blocks the IFN-induced nuclear accumulation of host phosphorylated STAT1, by interacting with the STAT1-binding region of host importin alpha-1/KPNA1 protein, thereby inhibiting the latter. Without the activity of this protein, activated STAT1 would not enter the nucleus and be unable to activate IFN-induced genes. Plays a role in assembly of viral nucleocapsid and virion budding. May act as a minor matrix protein that plays a role in assembly of viral nucleocapsid and virion budding.^{[1] [2] [3] [4]} [IMA6_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. Mediates nuclear import of STAT1 homodimers and STAT1/STAT2 heterodimers by recognizing non-classical NLSs of STAT1 and STAT2 through ARM repeats 8-9. Recognizes influenza A virus nucleoprotein through ARM repeat 7-9 In vitro, mediates the nuclear import of human cytomegalovirus UL84 by recognizing a non-classical NLS.

See Also

• Importin 3D structures
• VP24

References

1. ↑ Huang Y, Xu L, Sun Y, Nabel GJ. The assembly of Ebola virus nucleocapsid requires virion-associated proteins 35 and 24 and posttranslational modification of nucleoprotein. Mol Cell. 2002 Aug;10(2):307-16. PMID:12191476
2. ↑ Han Z, Boshra H, Sunyer JO, Zwiers SH, Paragas J, Harty RN. Biochemical and functional characterization of the Ebola virus VP24 protein: implications for a role in virus assembly and budding. J Virol. 2003 Feb;77(3):1793-800. PMID:12525613
3. ↑ Licata JM, Johnson RF, Han Z, Harty RN. Contribution of ebola virus glycoprotein, nucleoprotein, and VP24 to budding of VP40 virus-like particles. J Virol. 2004 Jul;78(14):7344-51. PMID:15220407 doi:http://dx.doi.org/10.1128/JVI.78.14.7344-7351.2004
4. ↑ Reid SP, Valmas C, Martinez O, Sanchez FM, Basler CF. Ebola virus VP24 proteins inhibit the interaction of NPI-1 subfamily karyopherin alpha proteins with activated STAT1. J Virol. 2007 Dec;81(24):13469-77. Epub 2007 Oct 10. PMID:17928350 doi:http://dx.doi.org/10.1128/JVI.01097-07
5. ↑ Xu W, Edwards MR, Borek DM, Feagins AR, Mittal A, Alinger JB, Berry KN, Yen B, Hamilton J, Brett TJ, Pappu RV, Leung DW, Basler CF, Amarasinghe GK. Ebola Virus VP24 Targets a Unique NLS Binding Site on Karyopherin Alpha 5 to Selectively Compete with Nuclear Import of Phosphorylated STAT1. Cell Host Microbe. 2014 Aug 13;16(2):187-200. doi: 10.1016/j.chom.2014.07.008. PMID:25121748 doi:http://dx.doi.org/10.1016/j.chom.2014.07.008