Notch inhibition suppresses phosphorylation of effectors in the mTOR pathway. (A) Five GSI-sensitive cell lines were exposed to either GSI (compound E) or vehicle (DMSO) for 7 days. After the incubation period, whole-cell lysates were prepared and equivalent amounts of total protein were loaded per lane on a polyacrylamide gel for Western blot analysis using the panel of antibodies shown on the left. (B) Similar experiment as in panel A except the cell lines were stably transduced with retroviruses expressing ICN1. The values shown below each blot represent ratios (phospho/total) of calibrated densitometry readings normalized to mock-treated (DMSO) control samples.