FIGURE 7.
Recruitment of the GBA motif of GIV to activated EGFR is sufficient to induce G protein activation. A, diagram depicting how Grb2 fused to the GBA motif (aa 1660–1705) of GIV (Grb2-GBA) is recruited from the cytosol to tyrosine phosphorylated EGFR at the plasma membrane upon activation. Grb2-mediated binding to EGFR brings the GBA motif close to membrane-bound Gi3. B and C, HEK293T cells were transfected with plasmids for all the components required BRET-based G protein activity measurements as described for Fig. 3, Grb2-GBA (WT or FA) and EGFR. EGF (50 ng/μl) was added at the indicated time (arrow in B). BRET results (B) are the averages of three or four independent experiments, and the error bars are the S.E. (shown only at 5-s intervals for clarity). Representative immunoblots of the cells used in these experiments are shown in C.