The redox status in MO7e cells regulates the tyrosine phosphorylation of growth factor receptors and STAT5. MO7e cells were left untreated (CTRL) or treated for 7.5 minutes with either GM-CSF (20 ng/mL), 20 minutes H₂O₂ (5 mmol/L) (PEROX), or pretreated with 1 mmol/L PDTC for 3 hours and then stimulated with GM-CSF (GM-CSF/PDTC) for 7.5 minutes. Tyrosine-phosphorylated proteins were detected in GM-CSF receptor βc and STAT5 immunoprecipitates by immunoblotting with an antiphosphotyrosine antibody (p-Tyr).