The constitutive STAT5 activation is reduced in substitution/deletion mutants of duplicated R595. FLT3-WT–, FLT3-ITD-W51–, FLT3-ITD-NPOS–, FLT3-W51-R602A–, FLT3-W51-R602E–, FLT3-W51-R602K–, FLT3-W51-ΔR602–, FLT3-W51-ΔE603–, and FLT3-NPOS-ΔR623–expressing cells were starved for 24 hours in the presence of 0.3% FBS. Blots were incubated with anti–phospho-STAT5 antibody, stripped, and reblotted with anti-STAT5 antibody.