Expression of IL-7Rα, but not IL-7Rα–Y449F, allows IL-7 to support cell survival, growth, glucose uptake, and surface Glut1 in cytokine-dependent cells. FL5.12 cells were transduced with control, wild-type IL-7Rα, or IL-7Rα–Y449F expression plasmids and stable clones were isolated for analysis. (A) Surface IL-7Rα levels were determined by flow cytometry. (B-E) Control, IL-7Rα–, and IL-7Rα-Y449F–expressing cells were washed and cultured in IL-3, no cytokine (none), or IL-7, and observed for (B) cell viability after one day, (C) cell growth over time, (D) Glut1 protein levels, and (E) glucose uptake after 8 hours. (F) Regulation of surface Glut1 trafficking was determined by transfecting control, IL-7Rα–, and IL-7Rα-Y449F–expressing cells with exofacially FLAG-tagged Glut1 (FLAG-Glut1). Cells were washed and cultured in IL-3, no cytokine (none), or IL-7 for 8 hours and surface FLAG-Glut1 was determined by flow cytometry. Values represent means plus or minus SEM of triplicate samples. By Student t test, *P < .02, **P < .001.