eIF2α is phosphorylated on S51 by four distinct kinases; PERK, heme-regulated inhibitor (HRI), protein kinase R (PKR), and general control non-depressible 2 (GCN2) which are activated by ER-stress, heme depletion, viral infection and amino acid starvation, respectively (30). Here, EIF2AK3 is linked to viral infectious disease.