E76K SHP-2 expression results in a hypersensitive pattern of CFU-GM colony growth. (A) SHP-2 expression levels in fetal liver cells transduced with retroviruses encoding WT, D61Y, or E76K SHP-2 proteins. The blot was also probed with an anti-ERK2 antibody to confirm equal protein loading. (B,D) CFU-GM colony growth of cells expressing either WT or E76K SHP-2 over a range of GM-CSF (B) or IL-3 (D) concentrations. Graphs display the average growth of 3 independent experiments of cells plated in duplicate. (C,E) Morphology of representative CFU-GM colonies grown in saturating concentrations of GM-CSF (C) or IL-3 (E) from fetal liver cells expressing WT or E76K SHP-2 proteins (original magnification, × 40).