Caveolin-1 is a critical regulator of TGF-β mediated hepatocyte apoptosis

Caveolae are small plasma membrane invaginations formed by caveolin-1. Besides the clathrin dependent internalization route, TGF-β ligand/receptor complexes internalize via caveolae. The lack of caveolin-1 leads to an increase of canonical Smad signaling via Smad2 and Smad3. However, we found that the knock down of caveolin-1 in hepatocytes abrogated the TGF-β mediated activation of the AKT pathway. Because TGF-β mediates hepatocyte dedifferentiation (EMT) as well as hepatocyte apoptosis in vitro, we analyzed the consequences of a loss of AKT activation upon TGF-β treatment. Interestingly, a Caspase 3 assay reve…