These are, the heme-regulated inhibitor (HRI) which gets activated under heme deficiency and several other conditions, the double-stranded RNA activated protein kinase (PKR) which gets activated during viral infection, the PKR-like endoplasmic reticulum-resident kinase (PEKR) which gets activated during the presence and accumulation of unfolded proteins in the endoplasmic reticulum and the general control non-derepressible 2 (GCN2) kinase which gets activated during nutrient starvation [10,11]. This evidence concerns the gene EIF2AK2 and viral infectious disease.