EIF4EBP1 and retinal ischemia: As shown in Fig. 5, retinal ischemia induced a transient dephosphorylation of mTOR (Ser2448), which corresponded with the kinase deactivation, as confirmed by the decreased phosphorylation of two mTOR downstream targets, ULK1 (Ser757) and 4EBP1 (Thr37/46) (Fig. 5A, B).