Effect of amino-terminal BRCA1 mutation in caspase-dependent apoptosis. BRCA1wt and BRCA1+ cells were treated with 1 μM STS and adherent populations were collected at 0, .5, 1, 1.5, and 3 h. Cells were lysed and separated via 12.5% SDS-PAGE for western immunoblot analysis. Membranes were probed with antibodies for activated caspase 9 (37 kDa), caspase 8 (43 kDa), caspase 3 (19 kDa), procaspase 7 (36 kDa), and full length DFF45 (45 kDa). Membranes were then reprobed with anti-actin to ensure proper loading (shown immediately under respective caspases). Membranes are representative of at least 3 independent treatments.