Notably, TRIM21 interacted with PKR but not eIF2α (Fig 2A and 2B), and the endogenous interaction between them was further confirmed in A549 cells, in which their interaction was enhanced upon viral infection or TG treatment (Fig 2C and 2D), indicating that TRIM21 may inhibit PKR activation by targeting PKR. This evidence concerns the gene TRIM21 and viral infectious disease.