PEA3 is required for Notch-4 reporter activity. Schematic representation of the Notch-4 luciferase construct (-650 to +1 region) indicating the wild-type (wt) and mutated (mut) AP-1 consensus sites and the wild-type Ets site. MDA-MB-231 cells were cotransfected with AP-1 luciferase and either scrambled (SCRBia) or PEA3 siRNA (PEA3ia). Cells were cotransfected with either wild-type AP-1 or mutated AP-1 Notch-4 luciferase and either scrambled or PEA3 siRNAa. Firefly luciferase was measured normalized to Renilla luciferase as an internal transfection control. Means and standard deviations of three or more experiments were plotted. Statistical significance was determined by performing a two-tailed, unpaired Student's t-test.