Figure 2.

NIK pro-death function acts through the TNFR1/RIP1-dependent apoptotic axis. (a) NIK^+/+ and NIK^−/− mouse embryonic fibroblasts (MEFs) were stimulated with TNFα and CHX (5 μg/ml) for the indicated time periods, and cell survival was measured using the Cell Titer-Glo Kit. (b) NIK^+/+ and NIK^−/− MEFs were treated for 24 h with or without TNFα and the SMs CmpA, and cell survival was measured similar to panel (a). (c and d) Analysis of DEVDase activities in WT MEFs treated with Tweak and/or TNFα or LTβR Ago and/or TNFα in the absence or presence of the caspase inhibitor z-VAD-FMK and/or Nec-1. Statistical analyses: ***P<0.001. (e and f) MEFs were treated with Tweak/TNFα or LTβR Ago/TNFα in the absence or presence of Nec-1 for the indicated time periods prior to an immunoprecipitation with an anti-caspase-8 antibody and detection of both caspase-8 and RIP1 by western blotting