Kinase inhibitors block activation at multiple points in EGFR/AP-1 pathway. Inhibitors decrease the response of the AP-1-bla ME180 CellSensor when stimulated with EGF. β-lactamase was measured using Invitrogen's LiveBLAzer™ assay (Panel A). Percent inhibition is determined in comparison to untreated sample and represents the mean of (± SEM) eight independent data points (n = 8). Photomicrographs of cells were obtained under fluorescent microscopy (Panel B).