FIGURE 8.

IE86 protein inhibits STING-induced TBK1 activation. (A) HEK293T cells were transfected with the vector expressing STING or TRIF with control or IE86 expression vector. At 24 h after transfection, equal amounts of cell extracts were subjected to western blot analysis with antibodies to phospho-TBK1, TBK1, STING, FLAG, HCMV IE86 and tubulin. (B) HEK293T cells were co-transfected with the vector expressing STING or TRIF, control renilla luciferase reporter and IFN-β promoter-driven firefly luciferase reporter plasmids plus control or IE86 expression vector. At 48 h, IFN-β promoter-driven luciferase activity was measured using a dual luciferase assay system. IFN-β promoter-driven luciferase activity was expressed in RLU by normalizing firefly luciferase activity with constitutive renilla luciferase activity. Luciferase data shown here represent three independent experiments ±SD. The asterisk (^∗) denotes a significant difference between samples, which was determined by the P-value of a two-sample t-test (P < 0.05).