In addition to be activated by the cellular RNA, PKR is suppressed during binding with the cytoplasmic circular RNAs (circRNAs) that tend to form 16–26 bp imperfect RNA duplexes, and viral infection relieves this inhibition following circRNAs degradation by RNase L to activate PKR activity (Liu et al, 2019). The gene discussed is EIF2AK2; the disease is viral infectious disease.