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Proteolytic cleavage of beta-catenin by caspases: an in vitro analysis
M Van de Craen1, G Berx, I Van den Brande
1Department of Molecular Biology, Flanders Interuniversity Institute for Biotechnology, University of Gent, Belgium.
Abstract:
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 beta-catenin. During apoptosis, both an N-terminal and a small C-terminal part are removed from beta-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 beta-catenin in vitro. However, the beta-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 beta-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 beta-catenin.
Insights
Caspase-3, -6, and -8 directly cleave beta-catenin during apoptosis, affecting cell adhesion. Different caspases generate distinct beta-catenin fragments, influencing cellular responses.
Area of Science:
- Biochemistry
- Cell Biology
- Molecular Biology
Background:
- Apoptosis involves structural protein cleavage by caspases, leading to morphological changes.
- Beta-catenin links actin filaments to cadherins in cell-cell adhesion complexes.
- During apoptosis, beta-catenin undergoes N-terminal and C-terminal cleavage, potentially disrupting cell adhesion.
Purpose of the Study:
- To investigate the direct proteolysis of beta-catenin by specific caspases.
- To determine if different caspases generate distinct beta-catenin cleavage products.
- To understand the role of differential beta-catenin proteolysis in apoptosis.
Main Methods:
- In vitro assays were used to test the cleavage of beta-catenin by various caspases.
- Analysis of beta-catenin cleavage products generated by different caspases.
Main Results:
- Caspase-8, -3, and -6 were found to directly proteolyze beta-catenin in vitro.
- Caspase-8 generated different beta-catenin cleavage products compared to caspase-3 and -6.
- Caspase-1, -2, -4/11, and -7 showed minimal or no cleavage activity on beta-catenin.
Conclusions:
- Specific caspases (caspase-3, -6, -8) directly cleave beta-catenin.
- Differential cleavage of beta-catenin by various caspases may occur depending on the activating stimuli.
- This differential proteolysis could contribute to the diverse cellular events during apoptosis.