FIG. 5.
Bcl-xL and Bcl-2 inhibit Bid-induced oligomerization and insertion of Bax into the outer mitochondrial membrane. (A to C) Mitochondria isolated from HeLa cells were incubated with 100 nM Bid in the presence of 1 μM recombinant Bcl-xL or Bcl-xLm at 30°C for 15 min. Mitochondria were used to study Bax insertion into the outer mitochondrial membrane (A), cytochrome c release (B), and Bax dimerization (C). (D) Mitochondria from HeLa cells overexpressing Bcl-2 were isolated and incubated with 100 nM Bid at 30°C for 15 min and used to analyze Bax insertion into the outer mitochondrial membrane. Att., attached (alkali sensitive); Ins., inserted (alkali resistant); Ctl., Cont., control; Cyt.c, cytochrome c.