“…RNAs, with a minimum of 33 bp, bind to its dsRNA-binding domain (172,173). Due to the strict requirement of dsRNA activation, PKR activity in the liver is often correlated with viral infections such as hepatitis C (174)(175)(176)(177). It is no surprise then that hepatitis C infection increases FGF21 mRNA abundance in the liver, presumably through PKR-mediated phosphorylation of eIF2α and enhanced transactivation of ATF4 to the FGF21 promoter (178).…”