Schematic overview of Jak/Stat signaling pathways. IL-6 signals through gp130, which is a common receptor chain for IL-6 and the IL-6 receptor. Hepatocytes express high level of gp130 and IL-6. IL-6 binding to its corresponding receptors leads to the dimerization of gp130, followed by dimerization of gp130-associated Jak 1 and Jak2, and phosphorylation of Jaks and gp130. This receptor-kinase complex then recruits and phosphorylates cytoplasmic protein Stat3. Phosphorylated Stat3 forms dimers, translocates into the nuclei, and induces gene transcription. Binding of IL-10 to its corresponding receptors IL-10R1 and IL-10R2 leads to Jak and then Stat3 phosphorylation, which then functions as a transcription factor.
