Hypersensitive CFU-GM colony growth induced by E76K SHP-2 is dependent on PTPase activity but does not require the β_c subunit. (A) CFU-GM colony growth of fetal liver cells expressing WT SHP-2, WT-C463S (catalytically inactive WT SHP-2), E76K SHP-2, or E76K-C463S (a catalytically inactive E76K mutant SHP-2) over a range of GM-CSF concentrations. Cells expressing WT, WT-C463S, and E76K-C463S SHP-2 proteins all demonstrate a normal pattern of CFU-GM colony growth. (B) CFU-GM colony growth of WT and β_c-deficient (β_c^-/-) bone marrow cells transduced with WT or E76K SHP-2 vectors over a range of IL-3 concentrations. The β_c^-/- bone marrow cells expressing E76K SHP-2 demonstrate a hypersensitive response that is similar to WT bone marrow cells. Error bars indicate the standard deviations of duplicate plates.