EIF2AK2 and viral infectious disease: The protein kinase R (PKR) responds to dsRNA in viral infections; PKR-like ER kinase (PERK) acts to counter endoplasmic reticulum (ER) and oxidative stress; general control nonderepressible 2 (GCN2) senses nutrient depletion; and heme-regulated EIF2α kinase (HRI) senses heme deprivation, drugs, and toxicants [15,16].