Figure 2.

Baculovirus IAPs do not block active caspase-induced apoptosis. Sf-21 cells were cotransfected with plasmids expressing the active subunits of Sf-caspase-1 (p19 + p12) (A), the active subunits of mammalian caspase-3 (p17 + p12) (B), or the zymogen form of mammalian pro-caspase-1 (p45) (C), and a plasmid expressing one of the following as indicated in the figure: CAT, P35, CrmA, OpIAP, CpIAP, AcIAP, Bcl-2, Bcl-x_L, E1B19K, or CED-9. Apoptosis was quantitated as described in Material and Methods. The results presented are relative to viability of cells transfected with cat-expressing plasmid alone (not shown) set at 100%. Bars = SD of at least two independent experiments, each with two replications.