Related Experiment Video
Updated: Aug 30, 2026

Reconstitution Of β-catenin Degradation In Xenopus Egg Extract
Published on: June 17, 2014
Crystal structure of a beta-catenin/axin complex suggests a mechanism for the beta-catenin destruction complex
Yi Xing1, Wilson K Clements, David Kimelman
1Department of Biological Structure, University of Washington, Seattle, Washington 98195, USA.
Abstract:
The "beta-catenin destruction complex" is central to canonical Wnt/beta-catenin signaling. The scaffolding protein Axin and the tumor suppressor adenomatous polyposis coli protein (APC) are critical components of this complex, required for rapid beta-catenin turnover. We determined the crystal structure of a complex between beta-catenin and the beta-catenin-binding domain of Axin (Axin-CBD). The Axin-CBD forms a helix that occupies the groove formed by the third and fourth armadillo repeats of beta-catenin and thus precludes the simultaneous binding of other beta-catenin partners in this region. Our biochemical studies demonstrate that, when phosphorylated, the 20-amino acid repeat region of APC competes with Axin for binding to beta-catenin. We propose that a key function of APC in the beta-catenin destruction complex is to remove phosphorylated beta-catenin product from the active site.
Related Concept Videos
Catenins
Catenins in Cell Junctions
Catenins bind to cell adhesion molecules such as cadherins and link them to different cytoskeletal proteins depending on the type of cell junction. At the adherens...
Tension Response at Adherens Junctions
α-Catenin as a Mechanosensory Protein
The α-catenin of adherens junctions is an allosteric protein with three VH (vinculin homology) domains...
Structure of Cadherins
Anaphase Promoting Complex
Actin Filament Depolymerization
In F-actin, the ADF/cofilin proteins...
Caspases
