Fig. 2.

Heat-induced cytochrome c release is regulated by Bcl-2 proteins. (A) Mouse-liver mitochondria were enriched and heated with 200 μg/ml recombinant WT Bcl-xLΔC or mutant Bcl-xL(G138A)ΔC (mut) at 43°C for 1 h. After an additional incubation at 37°C for 1 h, cytochrome c release from the mitochondria (pellet) to the supernatant was assayed by Western blot. (B) Enriched mitochondria, heated at 43°C as indicated, were treated with 1 mM bismaleimidohexane (BMH) crosslinker or DMSO (vehicle control) and analyzed by Western blot using an anti-Bak antibody. (C) Mitochondria were either heated with 200 μg/ml WT or mutant (mut) Bcl-xLΔC at 43°C for 1 h or incubated with 45 nM active N/C Bid at 37°C for 1 h. Samples were treated and assessed for Bak oligomerization as in B. Arrows indicate crosslinked oligomers.