Figure 2. UVB-activated NF-κB depends on IKK and TBK1.

(A) SK-Mel-28 cells were pre-treated with the IKK inhibitor TPCA-1 (1 µM, IKKi) and TBK1 inhibitor Amlexanox (20 μM, TBKi), and then were exposed to UVB (50 mJ/cm²). After 4 h, the cell lysates were examined by EMSA (NF-κB) and western blot as indicated. (B) Wild-type (IKKα/β^+/+) or IKKα/β-deficient (IKKα/β^−/−) MEFs were treated with UVB (50 mJ/cm²), and the activation of NF-κB, TBK1 and IRF3 was examined by western blots. (C) SK-Mel-28 cells were exposed to UVB (50 mJ/cm²) with or without TBK1i. Cells were harvested at 4 h after UVR, TBK1 was immunoprecipitated (IP) and used for TBK1 kinase assay with GST-IKKβ as substrate. (D) WT and TBK1-knockout (KO) SK-Mel-28 cells were treated and analyzed as in (B).