Untreated (–) and treated (+) A431 whole cell extracts (30 μg) were separated by 7.5% SDS-PAGE, and the membrane was blotted with EGFR (phospho Ser1046/Ser1047) antibody (GTX133593) diluted at 1:1000. The HRP-conjugated anti-rabbit IgG antibody (GTX213110-01) was used to detect the primary antibody.