FIGURE 2.
p53 stabilization by pX via the p38MAPK pathway. A, Western blot of p38MAPKα using WCE from 4pX-1 and 4pX-1-p38MAPKαkd cell lines. Quantification is by the Scion software, relative to actin. B, confluent 4pX-1 and 4pX-1-p38MAPKαkd cells grown with (+) or without (-) pX, were incubated in 2% fetal calf serum to initiate apoptosis (21). Cycloheximide (10 μm) was added 2 h after onset of apoptosis, for the indicated time course. WCE isolated 0–180 min after treatment with cycloheximide, immunoblotted for p53. Actin is the internal control. A representative assay is shown from at least three independent experiments. C, quantification by the Scion software of p53 immunoblots shown in B, expressed as % p53 remaining versus min of cycloheximide treatment. Quantification is relative to actin, from at least three independent experiments. Error bars represent S.D.