Role of IKKα in type I IFN-dependent and independent STAT1 phosphorylation induced by dsRNA.

<p>(A) HeLa cells were transfected with siRNA targeting IKKα or control siRNA for 48 h. Then, the cells were treated with an anti-IFNAR neutralizing antibody for 1 h followed by transfection with poly I:C (50 ng/well) for an additional 4 h. HeLa cells were also treated with IFN-β (200 IU/ml) for 15 min as a control to confirm the neutralizing activity of the anti-IFNAR antibody. (B) IFNAR-null U5A cells were transfected with siRNA targeting IKKα or control siRNA for 48 h, and the cells were then further transfected with poly I:C (500 ng/well) for 10 h. Cell extracts were analyzed by immunoblotting. The results are representative of three independent experiments.