FIGURE 4.

Caspase-8 is required for the proteasome-mediated degradation of IRF-3. A, HT1080 cells were transfected with poly(I:C) in the absence or the presence of an inhibitor of caspase-8 (z-IETD, 10 μm) for the indicated times, and cell lysates were analyzed for IRF-3 by Western blot; B, ARPE19 cells expressing Wt caspase-8 were transfected with poly(I:C) for the indicated times, and cell lysates were analyzed for IRF-3 by Western blot; C, lysates from HT1080, ARPE19, and caspase-8 expressing ARPE19 cells were analyzed for caspase-8 by Western blot.