Protein kinase R inhibits the translation of mRNA of cell and pathogen

 One of the most important and famous gene among interferon-stimulated genes is protein kinase R (PKR). PKR is activated by double-strand RNAs that arise from RNA virus infection.
 PKR phosphorylates eukaryotic translation initiation factor 2alpha (eIF2a). eIF2a is a cellular protein that is essential for the transport of methionyl-tRNA to the translation initiation site of mRNA. eIF2a is inactivated by phosphorylation. Accordingly, the phosphorylation of eIF2a by PKR stops the cellular and viral protein translation, which contributes to the inhibition of viral growth in the cell.