FIGURE 9.

z-VAD efficiently prevents PPAN-mediated PARP cleavage but not NPM and UBF destabilization. A, loss of PPAN induces pan-caspase-dependent PARP cleavage. Transiently transfected HeLa cells were incubated with higher doses of the pan-caspase inhibitor z-VAD (100 μm) for 48 h as indicated. Control samples were incubated for 48 h without z-VAD. Whole cell lysates were analyzed by Western blotting using antibodies against PARP, NPM, UBF, PPAN, and GAPDH. Numbers indicate kDa. WCL = whole cell lysate. B, quantification of A. Relative levels of cl. PARP normalized to GAPDH as determined by densitometry. Error bars show S.E.M. Statistically significant differences are indicated by asterisks. 1st lane was set to 1. *, p < 0.05, n = number of independent experiments. C and D, quantification of NPM (C) and UBF (D) from A as shown in B. *, p < 0.05, n = number of independent experiments.