(A) Yeast cells displaying SPY1148 on the cell surface were labeled with biotinylated synthetic peptides corresponding to the pTyr1148 or Tyr1148 sites in EGFR, followed by secondary labeling with streptavidin-PE (SAPE). A control sample of yeast cells labeled with only SAPE is also shown. (B–D) Normalized membrane recruitment of SPY1148 in response to EGF stimulation of NR6 cells expressing wild-type EGFR (B, n = 213 cells from 8 independent experiments), the c’1000 EGFR truncation mutant (C, n = 144 cells from 5 independent experiments), or the c’1000F EGFR mutant with the Y992F mutation (D, n = 144 cells from 5 independent experiments). EGFR compared to c’1000 and c’1000f are significantly different, p <0.0001 by two-way ANOVA) 95% confidence intervals are shaded in (B–D).