(G) Quantification of phospho-4EBP1 protein levels in wild-type and GCN2-KO MEF cells upon starvation for 2 h (the mean ± SD of the fold increase of the phospho-4EBP1 to total 4EBP1 ratio from three independent experiments, one-way ANOVA analysis versus starvation treated wild-type cells, ***p < 0.001). 