FIG. 2.

Proteolytic cleavage of Rac1 and Rac2 during apoptosis is inhibited by caspase 3 inhibitors. JLP-119 cells were pretreated with different concentrations of tetrapeptide inhibitors of caspase 3 (z-DEVD), caspase 8 (z-IETD), caspase 9 (z-LEHD), or a broad-spectrum caspase inhibitor (z-VAD) for 1 h and then incubated with 8.5 μM VP-16 for an additional 6 h. The extent of apoptosis (A) and cleavage of Rac1, Rac2, and PARP (B) were measured as described in the legend to Fig. 1.