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. Author manuscript; available in PMC: 2016 May 1.
Published in final edited form as: Virology. 2015 Apr 3;0:122–130. doi: 10.1016/j.virol.2015.03.030

Figure 3. Filoviruses block IFN signaling.

Figure 3

Addition of IFNα or IFNβ to cells triggers a Jak-STAT signaling pathway which leads to tyrosine phosphorylation of STAT1 and STAT2. These dimerize and enter the nucleus through interactions with karyopherin alpha (KPNA) proteins. In the nucleus, a STAT1-STAT2-IRF9 complex activates IFN-stimulated response element (ISRE)-containing promoters. This leads to the upregulation of IFN stimulated genes such as MHC Class 1 and PKR. Ebola virus VP24 (eVP24) blocks interaction of phospho-STAT1 with KPNA proteins, preventing STAT1-STAT2 nuclear import. Marburg virus VP40 (mVP40) inhibits Jak1 function.