BAX and infection: Using these conditions, DKO MEFs were completely refractory to H2O2- and ionomycin-induced necrosis as assessed with annexin V and PI labeling (Figure 1F,G; compare with Figure 1—figure supplement 1C,D), but all deaths were restored in DKO MEFs containing a stably integrated Bax or Bak viral–based expression cassette, or acutely by infection with a recombinant Bax encoding adenovirus, collectively indicating that there is not an unrelated defect in the DKO MEFs (Figure 1H,I).