Untreated (–) and treated (+) A431 whole cell extracts (15 μg) were separated by 10% SDS-PAGE, and the membrane was blotted with p90 RSK1 (phospho Thr573) antibody (GTX133612) diluted at 1:1000. The HRP-conjugated anti-rabbit IgG antibody (GTX213110-01) was used to detect the primary antibody.