Figure 7.

Bcl-2 family members maintain their proapoptotic and antiapoptotic functions in the presence of uncouplers of ΔΨm. (A) Confocal micrographs of immunocytochemistry of Bax (left) in Cc-GFP-HeLa cells treated with UV (180 mJ/cm²) for 6 h in the absence (top) or presence (bottom) of FCCP (5 μM). Cytochrome c–GFP fluorescence (right) in the same cells is also shown. (B) Permeabilized HeLa cells were treated with tBid (20 μg/ml) or Bax (10 μg/ml) in the absence (left) or presence (right) of FCCP (5 μM). Cytochrome c–GFP fluorescence was detected by flow cytometry in FL-1. Release of cytochrome c–GFP was observed as a drop in overall fluorescence in the cells. (C) Cc-GFP-HeLa cells, which overexpress Bcl-2, were treated with UV (180 mJ/cm²) in the presence or absence of FCCP (5 μM), CCCP (10 μM), or DNP (800 μM). Cells were harvested after 6 h and assayed for phosphatidylserine exposure or cytochrome c–GFP release. The extent of annexin V binding and cytochrome c–GFP release was compared with cells that did not express Bcl-2, which were treated with UV at the same time. Bars, 20 μm.