FIG. 3.

RNAi-mediated knock-down of TRAF2 expression results in diminished CD40-induced NF-κB, JNK, and p38 activation in epithelial cells. (A) EJ bladder carcinoma cells were transfected with siRNA targeting TRAF2 or the unrelated luciferase gene product. Lysates were analyzed for TRAF2 or β-actin levels by immunoblotting. (B to D) Parallel cultures were stimulated with CD40L or left untreated. Lysates were isolated and analyzed for the expression of IκBα (B) and of the phosphorylated and total JNK (C) and p38 (D) by immunoblotting. Data from three independent experiments were quantitated using the Scion Image processing and analysis software and are expressed as the increase (n-fold) relative to unstimulated controls. NS, nonspecific. (E) The RNAi-mediated knock-down of TRAF2 does not affect IL-1-induced signaling. Cells were transfected with TRAF2 or luciferase siRNA as described in panel A and stimulated with 15 ng/ml IL-1 for 20 min prior to evaluation of the endogenous IκBα levels and of JNK and p38 phosphorylation by immunoblotting.