Figure 4. Sensitivity of MEK1 mutants to allosteric MEK inhibitors is associated with their RAF dependency.

A–C, WT or mutant MEK1 tagged with V5 were expressed in NIH3T3 cells upon cultured in medium containing doxycycline (300 ng/ml) for 24 hrs. Cells were then treated for 1 hr with increasing concentrations of three different allosteric MEK1 inhibitors CH5126766 (A) or PD901 (B) or Trametinib (C). IC50 of p-ERK inhibition to all three drugs were calculated on the basis of densitometry analysis of western blot results.