Endocytosis regulates TGF-β-induced Akt signal transduction in hepatocytes

TGF-β is a mayor cytokine in liver physiology. It regulates both cell proliferation and apoptosis of hepatocytes, and is the main drive of fibrosis, a typical complication of chronic liver diseases. An important feature of the signal transduction events is endocytosis of the receptor complexes. For TGF-β this remains a controversial issue, since independent approaches have shown either no effect or an important participation of endocytosis in its signal transduction. We addressed the importance of endocytosis in the regulation of TGF-β signaling in the cell line Hepatoma 1–6 and in primary mouse hepatocytes. In…