FIGURE 7.

IKK2 controls S6K degradation in response to TNF-α. A, signaling proteins in the NF-κB pathway. The Western blot was conducted with liver lysates of five p50-KO mice and five control mice. The results are consistent among mice in each group. A representative blot with one mouse in each group is shown. B, Iκbα mRNA in liver. The result represents the mean ± S.E. (n = 5). C, IKK2 deficiency. IKK2 phosphorylation and IκBα degradation were examined in primary hepatocytes treated with TNF-α (10 ng/ml) for 15 min. D, S6K degradation in Ikk2^−/− cells. The MEF cells were treated with TNF-α (10 ng/ml) in serum-free medium for the times indicated. E, inhibition of S6K degradation by the proteasome inhibitor in Ikk2-KO cells. MG132 (15 μm) was added into the medium at 30 min before the 4-h treatment with TNF-α. F, mTOR in S6K activation by TNF-α. HepG2 cells were pretreated with the mTOR inhibitor rapamycin (Rap, 200 nm) or the IKK2 inhibitor 15dPGJ2 (15d, 5 μm) followed by TNF-α treatment. pS6K (Thr-389) and pIRS-1 (Ser-636) were examined in a Western blot. The Western blot experiments were repeated three times with consistent results. Representative blots are presented. *, p < 0.05 by Student's t test (n = 5).