Proteolytic cleavage of β-catenin by caspases: an in vitro analysis

Cleavage of structural proteins by caspases has been associated with the severe morphological changes occurring during the apoptotic process. One of the proteins regulating the connection of the actin filament with cadherins in a cell-cell adhesion complex is β-catenin. During apoptosis, both an N-terminal and a small C-terminal part are removed from β-catenin. Removal of the N-terminal part may result in a disconnection of the actin filament from a cadherin cell-cell adhesion complex. We demonstrate that caspase-8, -3 and -6 directly proteolyse β-catenin in vitro. However, the β-catenin cleavage products generated by caspase-8 were different from those generated by caspase-3 or caspase-6. Caspase-1, -2, -4/11 and -7 did not or only very inefficiently cleave β-catenin. These data suggest that activation of procaspase-3, -6 or -8 by different stimuli in the cell might result in a differential proteolysis of β-catenin.