Gadd45β abrogates Fas-induced mitochondrial depolarization. Shown are percentages of JC-1⁺ cells in Neo, HA-Gadd45β, Bcl-x_L, and DN-FADD clones left untreated or treated with anti–APO-1 for the times indicated. Positivity was scored based on the combined increase in FL-1 fluorescence and decrease in FL-2 fluorescence. Values represent the mean ± standard deviation of 3 independent experiments.