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. 2000 Apr 18;97(9):4666–4671. doi: 10.1073/pnas.090082297

Figure 4.

Figure 4

Loss of outer mitochondrial membrane permeability after growth factor withdrawal is prevented by Bcl-xL expression. (A) Bcl-xL- and control- (Neo) transfected FL5.12 cells were cultured in the presence or absence of IL-3 for 12 h before the determination of ATP and phosphocreatine. The amount of ATP was determined by the luciferin/luciferase method, and the amount of phosphocreatine was determined by HPLC. The percent change in cellular ATP and creatine phosphate (Cr-P) measured on IL-3 withdrawal for each population is shown. The data presented are the mean (+SEM) of at least four independent determinations. The changes in ATP and phosphocreatine observed in both cases were statistically significant by Student's t test (P < 0.01). (B) Bcl-xL- and control- (Neo) transfected cells were cultured in the presence or absence of IL-3 for 12 h, and perchloric acid extracts normalized to mitochondrial protein were prepared. The mean (+SEM) amount of creatine phosphate present in the mitochondrial extracts from four independent experiments is shown. (C) Bcl-xL- and control- (Neo) transfected cells that were cultured in the presence of IL-3 or deprived of IL-3 (-IL3) for the time indicated were mechanically lysed and separated into mitochondrial (M) and S-100 (S) fractions. The cytosol is represented in the S-100 fraction. The amount of cytochrome c and cytochrome oxidase subunit IV in each fraction was determined by Western blot analysis. (D) Perchloric acid extracts were prepared from equal numbers of Bcl-xL- and control- (Neo) transfected cells that were withdrawn from IL- 3 for the period indicated. Cellular phosphocreatine was measured by using HPLC, and the percent change in phosphocreatine over time is graphed. The data presented are the mean (+SEM) of five independent experiments.