Figure 7.

Induction of PI3K signaling by eIF2α kinases requires eIF2α phosphorylation. (A) GyrB.PKR cells were left untransfected or transfected with siRNA for the luciferase reporter gene (Luc; negative control) or siRNA for eIF2α for 72 h followed by treatment with 100 ng/ml coumermycin for 6 h. (B) GyrB.PKR and GyrB.PKRT487D cells were left untreated or treated with coumermycin for the indicated times. (C) HT1080 cells were left untreated or pretreated with 20 μM LY294002 for 1 h before treatment with 75 μM Sal003 for the indicated times. (D) eIF2α S/S and eIF2α A/A MEFs were left untreated or treated with thapsigargin (TG; 1 μM) for indicated times. (A–D) Protein extracts (50 μg) were subjected to immunoblotting against the indicated proteins. The data represents one out of three reproducible experiments.