Role of PKR in Interferon Induction and Antiviral Response

Protein kinase receptor (PKR) belongs to a family of pattern-recognition receptors (PRRs). It can be induced by interferons (IFNs) as well as dsRNA from viral sources. It is a cytoplasmic kinase that responds to viral and IFN triggers mainly by apoptosis of the host cell or by inhibition of translation, affecting both viral and cellular mRNA. Protein synthesis is inhibited by phosphorylating the translation initiation factor eIF2alpha. Apoptosis can be activated via death receptor pathways involving FADD and the caspases, as well as by direct phosphorylation of p53. Much of PKR signal transduction, however, occurs via NF-κB and MAPK pathways, which trigger various antiviral effects especially the production of type I IFNs and increased expression of pro-apoptotic factors. (Upgraded 01/2020)