Dose response of STAT5 tyrosine phosphorylation in Ba/F3–EPO-R cells.

Ba/F3–EPO-R cells were incubated for 4 hours in the absence of cytokine and then stimulated with various concentrations of either murine IL-3 (lanes 2-6) or human EPO (lanes 7-12) for 10 minutes as shown. Activation-specific STAT5 (top) and STAT5 antibodies (bottom) were used in immunoblotting experiments as described in the legend to Figure 1.