EIF2AK2 and infection: During the early stages of infection, host PKR activation is inhibited by IAV to permit viral replication, by (i) masking of viral dsRNA using its nonstructural protein 1 (NS1) to prevent PKR activation [153], and (ii) activation of the PKR inhibitor P58IPK through nucleoprotein (NP)-mediated dissociation of Hsp40 from the Hsp40–P58IPK complex [154].