FIG. 3.

TTV ORF2 protein inhibits IκBα protein degradation. (A) HeLa cells were transfected with either the empty vector pcDNA3.1(−) or pcDNA3.1(−)-TTV2. At 48 h posttransfection and after stimulation with TNF-α (10 ng/ml) for 1 h or no stimulation as indicated, cell extracts were prepared and IκBα expression was determined by Western blotting using anti-IκBα antibody. β-Actin was used as a control. (B) HeLa cells were transfected with either the empty vector pcDNA3.1(−) or pcDNA3.1(−)-TTV2. At 48 h posttransfection and after being treated with TNF-α (10 ng/ml) and the proteasome inhibitor MG-132 (20 μM) for the indicated times, cell extracts were prepared and phosphoserine IκBα levels were determined by Western blotting using anti-phosphoserine IκBα (P-IκBα) antibody. β-Actin was used as a control. Results are representative of three different experiments.