Figure 6.
Differential effects of zVAD-fmk and zLEHD-fmk on Cer production induced by CD95 ligation or DNA damage. Jurkat cells (J16) labeled with [14C]serine were left untreated or preincubated for 2 h in the presence of zVAD-fmk or zLEHD-fmk at the indicated concentrations before addition of anti-CD95 mAb (200 ng/ml), etoposide (10 μg/ml), or exposure to IR (30 Gy). Quantitation of cellular Cer was performed after 5 h (anti-CD95; open bars) or 15 h (Eto/IR; hatched bars and filled bars, respectively) of further incubation. Results are expressed as percentage inhibition (means ± SD) of the Cer response observed in the absence of inhibitor peptide. Shown are data from a representative experiment containing duplicate samples performed two times and showing similar results. zLEHD-fmk, benzoyloxycarbonyl-LEHD-fluoromethylketone.