FIG. 1.

Mitochondrial responses to Cif are determined by Bcl-2. (A) HL-60 cells were either left untreated or treated with 5 μM STS for 60 min, and then S-100 cytosolic extract was prepared from the cells. Aliquots of purified HL-60 (HL-60 Mit.) and Bcl-2:HL-60 mitochondria (Bcl-2:HL-60 Mit.) were incubated with 100 μg of the S-100 extract from untreated (Ctr S-100) or STS-treated (STS S-100) HL-60 cells for 15 min at 37°C, and then the samples were centrifuged to pellet the mitochondria. The pellet (P) and supernatant (S) were separated, and the cytochrome c (Cyt. c) content in each fraction was determined by Western blot analysis. A decrease in the cytochrome c content in the P fraction and a corresponding increase in the cytochrome c content the S fraction of a sample indicates that Cif had an effect on the mitochondria. (B) Western blot analyses of Bad, Bak, Bax, and Bcl-2 in mitochondrial extracts from HL-60 and Bcl-2:HL-60 cells. All lanes contained identical amounts of total protein.