Untreated (–) and treated (+) A431 whole cell extracts (30 μg) were separated by 5% SDS-PAGE, and the membrane was blotted with EGFR (phospho Tyr1173) antibody [GT1111] (GTX634793) diluted at 1:1000. The HRP-conjugated anti-mouse IgG antibody (GTX213111-01) was used to detect the primary antibody.