Fig. 5. P49 inhibits effector caspase proteolytic processing. (A and C) Processing of Sf-caspase-1 and -2. Activation of pro-Sf-caspase-1 initiates with cleavage at TETD↓G to generate intermediate p25, which is subsequently cleaved at DEGD↓G to generate the mature p19 and p12 subunits. Pro-Sf-caspase-2 is cleaved at AETD↓G to generate p18 and p12 subunits. (B and D) Effect of P49 on Sf-caspase-1 and -2 processing. SF21 lysates (3.8 × 10⁵ cell equiv) prepared at the hours (h) indicated after infection with wild-type p35⁺ virus (+P35), vP49 (+P49) or vΔp35 (–P49, –P35) were subjected to immunoblot analysis using α-Sfcasp1 (B) or α-Sfcasp2 (D) antiserum.