CASP8 and hereditary sensory and autonomic neuropathy: Figure 2A shows that in the presence of TRAIL, PARP was cleaved, yielding a characteristic 85 kDa fragment. The combination treatment of TRAIL and CIP also resulted in elevated activation of caspase-8, caspase-9, and caspase-3. In addition, we showed that TRAIL- and CIP-induced apoptosis was blocked by Benzyl carbonyl-Val-Ala-Asp-fluoromethyl ketone (z-VAD-fmk) peptide, a general caspase inhibitor (Figure 2B). We also found that z-VAD-fmk prevented the increase in apoptotic DNA accumulation due to treatment with CIP and TRAIL (Figure 2C).