Figure 2.

Effect of STATs pathway interacting with herpesviruses EBV and KSHV during lytic cycle and interferon signaling. (A) High level of STAT3 activated by IL-6 on binding with its cognate receptor regulates EBV entry to lytic cycle; it is inhibited by the protein PIAS3. (B) The JAK/STAT pathway downstream of type I interferon counteracted by herpesviruses EBV and KSHV encoded products; IFNAR binds IFN-alpha and beta, then recruited JAK1 and TYK2, the latter is inhibited by a EBV latent protein, LMP1, while the heterotrimer STAT1-STAT2-IRF9 formed after activation of JAK1/TYK2 is inhibited by EBV kinase BGLF4 and by KSHV encoded vIRF2. STAT, signal transducer and activator of transcription; EBV, Epstein Barr virus; KSHV, Kaposi sarcoma-associated herpesvirus; PIAS3, protein inhibitor of activated STAT3; JAK, Janus kinase; IFNAR, interferon alpha/beta receptor; TYK, tyrosine kinase; vIRF, viral interferon regulatory factor.