FIGURE 4.

Co-expression of JAK3 partially abrogates the γc inhibitory effect on IL-9Rα-mediated STAT3 activation by JAK1 V658F. HEK293 cells were transiently co-transfected with JAK1 wild-type or V658F, γc, IL-9Rα, and/or with JAK3 as the last component of IL-9R complex in addition to the STAT3-responsive luciferase reporter pGL3-pap1. 4 h post-transfection cells were incubated for 20 h with or without IL-9 and subjected to a luciferase assay. Results are the mean ± variation of duplicate samples. Similar results were obtained in three independent experiments.