Epo induces binding of Stat5 to β_IL3 . 32D/EpoR-Wt cells were starved for 12 hours and left unstimulated (C) or stimulated with 100 U/mL of Epo or 10 ng/mL of IL-3 for 1 minute. The cells were lysed and immunoprecipitated with anti-Stat5B. The immunoprecipitates were subjected to immunoblotting with anti-β_IL3 followed by reprobing with antiphosphotyrosine (αPY) and anti-Stat5B, as indicated.