FIG. 7.

Stx2 induction of HeLa cell apoptosis-related factors. Cells were removed at the indicated times and analyzed by immunoblotting. Caspase-3, caspase-6, caspase-8, and caspase-9 were cleaved, and cleaved lamin A and Bid (15 kDa) are shown. After treatment of HeLa cells with Stx1 (10 ng/ml), levels of activated Bid (15 kDa), measured by densitometry and compared with control levels (at 0 h), were increased 1.8- and 1.7-fold at 3 and 4 h, respectively. Cytochrome c was detected in the cytosolic fraction at 3 to 4 h after treatment with Stx1 (10 ng/ml). Endogenous XIAP levels were increased in a time-dependent manner. β-Actin was used as an internal loading control for equal amounts of protein.