Endocytosis in liver function and pathology

This chapter outlines the molecular and cell biological mechanisms that underlie endocytosis in the liver, including the diverse roles of endocytic vesicles in the cytoplasm and how these pathways are altered in liver disease. Endocytic vesicles are formed at plasma membrane as inward budding events that invaginate toward the cytoplasm. Clathrin-dependent endocytosis is a central and intensely studied process by which surface receptors are internalized. The role of receptor-ligand interactions in signaling clathrin-coated pit formation is unclear, but some studies suggest that receptors may directly recruit a specific subset of endocytic adaptors. Scission of clathrin-coated vesicles marks their separation from the plasma membrane. Clathrin-independent endocytosis is a category of internalization pathways that can be dynamin dependent and independent. In liver pathology, extracellular vesicles are thought to play a role in tissue signaling cell stress during non-alcoholic steatohepatitis and other hepatic insults. Hepatocytes possess a unique epithelial polarity that contributes to specialized endocytic vesicle trafficking routes.