EIF2AK2 and viral infectious disease: eIF2α can be phosphorylated by four stress-responsive kinases upon various stimuli, namely, double-stranded RNA activated protein kinase (PKR), general control non-repressed 2 (GCN2) kinase, heme-regulated inhibitor (HRI), and PKR like endoplasmic reticulum kinase (PERK), that become activated in response to viral infection, decreased nutrients, oxidizing agents, high salt levels, hypoxia, and heat-shock among others (Wek, 2018).