PERK (protein kinase R-like endoplasmic reticulum kinase) is activated by endoplasmic reticulum stress and by intracellular pathogens such as viruses and Leishmania, [14], GCN2 (general control nonderepressible 2) is activated by amino acid deprivation [15] and, finally, PKR (protein kinase R) is activated by double-stranded RNA, particularly in response to viral infection [16]. This evidence concerns the gene EIF2AK2 and viral infectious disease.