Fig. 2.

pS273R suppresses IFN-β induction mediated by STING, TBK1, or IRF3. A–C The expression plasmid of the signaling molecule STING (50 ​ng), TBK1 (10 ​ng), or IRF3 (50 ​ng) was transfected into HEK293T cells with IFN-β-Luc (20 ​ng), pRL-TK (2 ​ng), and S273R (100 ​ng) expression plasmids. At 24 hpt, cells were harvested for luciferase activity analysis. The expression of STING, TBK1, IRF3, pS273R and β-actin was analyzed by Western blotting. D–F Experiments were conducted as in (A) to (C) except that transfection was performed without IFN-β-Luc and pRL-TK. The mRNA level of IFN-β was analyzed by qRT-PCR. The expression of STING, TBK1, IRF3, pS273R and β-actin was analyzed by Western blotting. G–I The dual-luciferase reporter assay was performed as in panels (A) to (C) except that IRF3-Luc plasmid was used instead of IFN-β-Luc. The expression of all proteins was analyzed by Western blotting with β-actin as an internal control. Data are presented as mean ​± ​SD of three independent experiments. Statistical significance between groups was determined using a t-test with GraphPad Prism software. ∗P ​< ​0.05; ∗∗P ​< ​0.01; ∗∗∗P ​< ​0.001; ∗∗∗∗P ​< ​0.0001.