Figure 2.

Bcl-2 prevents Δψ loss in the absence of the permeability transition. (A–C) Effect of Bcl-2 on Δψ and the permeability transition. AH130 mitochondria (A and B, traces 1 and 2; C, ○) and AH130-Bcl-2 mitochondria (A and B, traces 3; C, •) (both at 1 mg of protein per ml) were treated with 10 μM tBuOOH in the presence of 1 nmol of CsA per mg of protein (trace 2) or in its absence (traces 1 and 3). Δψ was measured by Rh123 uptake (A), and PT was assessed by swelling (B) and by release of aspartate aminotransferase (C) in state IV respiration. (D–F) Effect of Bcl-2 on Δψ loss induced by ionophores in the absence of Ca²⁺. Mitochondria (1 mg of protein per ml) isolated from cells were treated with SF6847 (D), carbonylcyanide m-chlorophenylhydrazone (CCCP) (E), or valinomycin (F) at the indicated concentrations for 5 min, and Δψ was measured with a TPP⁺ electrode in state IV respiration. Data are representative of three experiments.