FIG. 6.

Effect of a dominant negative ASK1 on Cdc42-induced cell death. (A) Cdc42-induced apoptosis requires ASK1 activity. We coinjected 0.3 or 0.5 mg of ASK1-KR per ml, 0.1 mg of V12Cdc42 per ml, and 70-kDa Texas Red-dextran into SCG neurons. The cells were maintained in the presence of NGF, and the percentage of surviving cells was assessed 48 h after injection as previously described. The results are the means and standard errors of the mean of three independent experiments. ASK1-KR blocks Cdc42-induced death. The P value of ASK1-KR is <0.01 at 0.3 mg/ml and <0.001 at 0.5 mg/ml. (B) ASK1-KR blocks Cdc42-induced increase of phosphorylation of c-Jun. SCG neurons were coinjected with 0.5 mg of ASK1-KR per ml and 0.1 mg of V12Cdc42 per ml together with 5 mg of guinea pig IgG per ml to detect the injected cells and maintained in the presence of NGF. The cells were stained 24 h later with a specific anti-phospho–c-Jun antibody. The results are the means and standard errors of the mean of three independent experiments. The P value of ASK1-KR at 0.5 mg/ml is <0.01.