JNK activation is not required for Fas-mediated apoptosis

Fas ligation in the presence of cycloheximide induced Jun N-terminal kinase 1 (JNK1) and JNK2 phosphorylation, caspase activation and cell death in the IL-3-dependent cell line BAF3. Fas-mediated apoptosis was prevented by expression of dominant negative FADD but not inhibited by IL-3. To investigate the role of JNK activation in this process, we examined cells over-expressing a JNK-specific phosphatase M3/6. M3/6 prevented Fas stimulation of JNK, but did not affect Fas-mediated caspase activation or cell death, demonstrating that JNK activation is not required for these processes.