Fig. 3.
Cell death from SP600125/menadione treatment occurs from a block in early JNK activation and is independent of c-Jun phosphorylation. A: RALA hepatocytes were treated with dimethyl sulfoxide (DMSO) or SP600125 alone or with 50 μM menadione for the indicated hours. Total protein was isolated and immunoblotted for phospho- (P-c-Jun) and total (c-Jun) c-Jun, phospho- (P-JNK) and total (JNK) JNK, phospho- (P-ERK1/2) and total (ERK1/2) ERK1/2 and β-actin as a loading control. B: Cells were infected with Ad5LacZ or Ad5TAM and treated with 50 μM menadione. Total protein from these cells was immunoblotted with the same antibodies as in (A). C: Percentage cell death at 24 h in untreated control (Con) RALA hepatocytes, and cells treated with 50 μM menadione together with SP600125 1 h before (−1h), or 1 (+1h), 2 (+2h) or 4 (+4h) h after menadione treatment (*P<0.01, **P<0.001 as compared to cells treated with SP600125 1 h before menadione; n=4).
