Figure 3.

¹²⁵I-EGF competition-binding curves of WT and mutant EGF receptors treated without or with erlotinib or lapatinib. CHO cells expressing the indicated EGF receptors were treated without (black lines) or with erlotinib (green lines) or lapatinib (red lines) prior to and during incubation with labeled EGF. Increasing concentrations of unlabeled EGF were added to different wells. The data are normalized to control binding. Control binding represents the number of counts of ¹²⁵I-EGF bound by the untreated cells in the absence of any additional unlabeled EGF. Points represent the mean ± S.D. of triplicate determinations in a single experiment, which was repeated a minimum of three times.