EIF2AK4 and acute kidney injury: Based on the assumption that ISR-linked cellular processes are involved in modulating renal distress, the expression of four global stress-related mammalian eIF2α kinases, i.e., EIF2AK1 (HRI), EIF2AK2 (protein kinase R; PKR), EIF2AK3 (protein kinase R-like endoplasmic reticulum kinase; PERK), and EIF2AK4 (GCN2), were compared in patients with AKI (Fig. 1a).