G6 preferentially inhibits Jak2-V617F dependent constitutive activation of STAT5. HEL cells were treated with either increasing concentrations of G6 or with 25 μm G6 for increasing periods of time. The levels of phospho-STAT1 (pY701), phospho-STAT3 (pY705), and phospho-STAT5a/b (pY694/699) were then simultaneously measured. Dose- and time-dependent inhibition of phospho-STAT1 (A), phospho-STAT3 (B), and phospho-STAT5a/b (C) are shown. *, p < 0.05 versus DMSO control.