HNF4A and viral infectious disease: Evidence suggests JNK and extracellular signal-regulated kinases (ERKs) are activated by virus infection [67], and recent Western blot evidence indicates that JNK activates MAPK, which downregulates the expression of hepatocyte nuclear factor 4 alpha (HNF4) [68], and HNF-4 regulates the expression of certain OATs [69].