EIF2AK2 and viral infectious disease: These include (i) HRI [28], activated by heme deficiency to prevent excess globin translation in iron-deficient erythroid cells, (ii) PERK [29], activated by endoplasmic reticulum (ER) stress and heat/cold shock, (iii) GCN2 [30], activated by starvation and UV damage, (iv) MARK2 [31], activated by proteotoxic stress, and (v) PKR [32], activated by viral infection through sensing of double strand (ds)RNA.