Figure 7. Enhanced protein-protein interactions and downstream signaling by SHP2^T42A.

(A) Gab2 co-immunoprecipitation with SHP^WT, SHP2^E76K, SHP2^T42A and SHP2^T42A+E76K (42+76). Relative Gab2 co-immunoprecipitation levels are normalized for expression and shown in the bar graph. (B) Phospho-Erk (p-Erk) levels in response to EGF stimulation in cells expressing Gab2 with either SHP2^WT, SHP2^T42A SHP2^E76K (N = 3–6). The bar graphs below the blots show p-Erk levels, normalized to total Erk levels, relative to the highest p-Erk signal in the SHP2^WT time course (2 minutes). For all bar graphs, a paired, one-tailed t-test was used to test for significance (* denotes p < 0.05, ** denotes p < 0.01, *** denotes p < 0.001). (C) Representative histograms for Erk phosphorylation responses in wild-type, T42A, or E76K SHP2-expressing Jurkat variants stimulated with anti-CD3 antibody for the indicated time. The black bar in the first panel depicts the gate used to define the pErk+ population. (D) Geometric mean fluorescence intensity for phosho-Erk levels in SHP2^WT, SHP2^T42A or SHP2^E76K-expressing SHP2-deficient Jurkat variants (N = 3 stimulation replicates). (E) Geometric mean fluorescence intensity for CD69 levels in SHP2^WT, SHP2^T42A or SHP2^E76K-expressing SHP2-deficient Jurkat variants (N = 2 stimulation replicates). The data in panels D and E are representative of 5–6 biological replicates.