EIF2AK4 and viral infectious disease: In humans, three other eIF2α kinases can phosphorylate eIF2α and regulate translation: general control nonderepressible-2 (GCN2) activated by nutrient deprivation [27], heme-regulated initiation factor 2 alpha kinase (HRI) induced by heme deficiency and oxidative stress [28–30], and protein kinase interferon-inducible double-stranded RNA dependent (PKR) which is elicited by viral infection [31, 32].