EIF2AK1 and viral infectious disease: A number of eIF2α kinases are activated by various stress signals, including oxidative stress [heme-regulated inhibitor (HRI) or EIF2AK1], viral infection [protein kinase double-stranded RNA-dependent (PKR) or EIF2AK2], ER overload [PKR-like ER kinase (PERK) or EIF2AK3], and ROS accumulation or amino acid starvation [general control non-derepressible-2 (GCN2) or EIF2AK4].