Signal transduction pathways in liver and the influence of hepatitis C virus infection on their activities

Table 1 STATs activation and function

STAT protein	Activating factor	Activation effect
STAT 1	IFN-α/β (type I INF) IFN-γ (type II INF)	Antiviral response, inflammation and hepatocyte damage development, apoptosis stimulation
STAT 2	INF-α/β i INF-λ	Antiviral response
STAT 3	IL-6 and its family, IL-10, IL-22, EGF, HCV proteins	Participates in antiviral IFN-α effect, direct cytoprotective and anti-inflammatory influence on hepatocytes
STAT 4	IL-12	Probably plays a critical role in hepatocytes damage during hepatic ischemia/reperfusion injury and in Th1 differentiation
STAT 5	Growth factors	Regulates the genes expression essential for hepatocytes metabolism, growth and differentiation
STAT 6	IL-4, IL-12 and IL-13	Participates in Th2 lymphocytes response during viral hepatitis and decreases hepatocytes damage during hepatic ischemia/reperfusion injury