Figure 1. SUMOylation contributes to the optimal TNFα-mediated NF-κB activation and degradation of IκBα.

(A) HeLa cells were transfected 72 h with control or Ubc9 siRNA (100 nM). Cells were co-transfected with a NF-κB-luciferase reporter plasmid (3EnhancerConA) and β-galactosidase reporter. Twenty-four hours later cells were stimulated with TNFα (15 ng/ml) as indicated and luciferase and β-galactosidase activities measured as previously described [50]. The graph corresponds to the mean of three independent experiments. (B) HeLa cells were transfected during 72 h with control or Ubc9 siRNA (100 nM) and stimulated with TNFα (15 ng/ml) as indicated. Western-blot analyses were performed with the indicated antibodies.