Fig. 9. IEX-1 phosphorylation is required for its survival effect. (A) UT7 clones stably expressing HA-tagged Wt-IEX-1, T/SA3-IEX-1, ΔBD-IEX-1 or an empty vector (Neo) were deprived of cytokine and stained with annexin V–FITC at the indicated times. Similar results were obtained in three independent experiments. (B) CHO cells were transiently transfected with EGFP or EGFP-IEX-1 wild-type or mutant fusion proteins. Apoptosis was induced by treatment with STS for 7 h and measured in EGFP-transfected cells as described in Materials and methods. Results are mean ± SE of values from at least four independent transfections. (C) Total lysates from CHO cells transfected and treated as in (B) were analyzed by western blotting with anti-phosphoIEX-1 and anti-GFP antibodies.