EIF2AK1 and viral infectious disease: Four stress-related kinases have the ability to phosphorylate the alpha subunit, including PKR under viral infections, PERK due to ER stress, HRI kinase (heme-regulated inhibitor) under osmotic stress and oxidative stress, and GCN2 kinase activated under amino acid starvation (Aulas et al., 2017; Wolozin and Ivanov, 2019).