EIF2AK4 and viral infectious disease: PKR is induced upon viral infection and participates in the lysosomal clearance of misfolded proteins (Darini et al., 2019; Pataer et al., 2020; Wek, 2018), GCN2 activation depends on the ribosome P-stalk after amino acid depletion (Harding et al., 2019; Inglis et al., 2019; Ye et al., 2010), and the HRI kinase triggers the ISR when mitochondrial function is altered or heme is depleted.