Fig. 2.

Phospho-RelA protects MEFs from TNF-induced apoptosis. (A) Rela^−/− MEFs infected with an empty retrovirus (mock) or retroviruses expressing HA-tagged wt RelA, RelA(S534A), or RelA(S534E) were left unstimulated or were treated with TNF (20 h). Apoptotic cells were detected by TUNEL staining. Represented are averages ± SD of three separate experiments. Cell lysates were analyzed for caspase-3 activation, PARP cleavage, and RelA expression by immunoblotting. (B) Tbk1^−/− MEFs expressing RelA(S534A) or RelA(S534E) were treated for 3 h with TNF in the presence of CHX. Apoptotic cells were detected by TUNEL assay and quantified as described earlier. (C) Lysates were prepared from cells in B that were stimulated with TNF plus CHX for the indicated times. Caspase-3 activation and protein expression were determined by immunoblotting as in A.