IL4R I242N mutant induced STAT activation in DEV cells. Transduced DEV cells with retrovirus control (empty) or retrovirus expressing IL4R WT or hotspot I242N mutant under control of doxycycline (20 ng/mL, 48 hours) were treated with human recombinant IL-4 (20 ng/mL) for (A,C-D) 24 hours, (B) 20 minutes, or left UT. (A) mRNA expression of IL4R measured by quantitative real-time PCR. (B) Phosphorylation status of STAT3, STAT5, and STAT6 and protein level of IL4R were determined by western blot. (C-D) Flow cytometry analysis of cell-surface expression of IL4R represented as a (C) scatter plot and (D) bar plot. (C) Numbers represent the mean ± SD of the percentage of IL4R-expressing cells and the respective GM; the scatter plots correspond to representative data of 3 independent experiments. (A,D) Graphs show the mean ± SD of 3 independent experiments; significance was evaluated using 1-way ANOVA with Tukey posttest. *P < .05; **P < .01; ***P < .001. GM, geometric mean; n.s., nonsignificant.