Although both ceramide and interleukin-1β converting enzyme (ICE) family proteases are key molecules during apoptosis, their relationship remains to be elucidated. We report here that cell-permeable ceramide induced cleavage and activation of CPP32, a Ced-3/ICE-like protease, but not ICE. Ceramide-induced apoptosis of Jurkat cells was blocked by the CPP32-specific tetrapeptide inhibitor DEVD-CHO, but not by the ICE inhibitor YVAD-CHO. Furthermore, variant Jurkat cells with defective CPP32 activation were resistant to both antiFas- and ceramide-induced apoptosis. These results indicate that CPP32 activation is required for ceramide-induced apoptosis, and suggest sphingomyelin-ceramide pathway functions upstream of CPP32.
