Steady-state or stimulus-induced degradation of prosurvival Bcl-2 proteins limits their proapoptotic activity. (A) J16 cell lines transduced to express the individual prosurvival Bcl-2 proteins as N-terminal GFP fusions and sorted on equal protein levels (as in Figure 5A) were treated with a dose range of the indicated proapoptotic regimens. Cell death was assessed by PI uptake after 48 hours. Empty vector (E.V.) transduced cells were used as control and treated with Q-VD-OPH (E.V. Q) to show that cell death was apoptotic. (B) As in panel A, using etoposide and daunorubicin as proapoptotic regimens. Data shown are mean values ± SD derived from 3 independent experiments.