Reconstitution of the destruction complex defines roles of AXIN polymers and APC in β-catenin capture, phosphorylation, and ubiquitylation
| Autor: | Sebastian Guettler, Saira Sakalas, Ruth Knight, Mariola Zaleska, Michael Ranes |
|---|---|
| Rok vydání: | 2021 |
| Předmět: |
biology
Adenomatous Polyposis Coli Protein Ubiquitination Wnt signaling pathway Cell Biology Processivity Ubiquitin ligase Cell biology Axin Protein Ubiquitin Multiprotein Complexes Catenin Proteolysis AXIN1 biology.protein Humans Phosphorylation Protein Multimerization Axin Signaling Complex Wnt Signaling Pathway Molecular Biology beta Catenin |
| Zdroj: | Molecular Cell. 81:3246-3261.e11 |
| ISSN: | 1097-2765 |
| Popis: | Summary The Wnt/β-catenin pathway is a highly conserved, frequently mutated developmental and cancer pathway. Its output is defined mainly by β-catenin's phosphorylation- and ubiquitylation-dependent proteasomal degradation, initiated by the multi-protein β-catenin destruction complex. The precise mechanisms underlying destruction complex function have remained unknown, largely because of the lack of suitable in vitro systems. Here we describe the in vitro reconstitution of an active human β-catenin destruction complex from purified components, recapitulating complex assembly, β-catenin modification, and degradation. We reveal that AXIN1 polymerization and APC promote β-catenin capture, phosphorylation, and ubiquitylation. APC facilitates β-catenin's flux through the complex by limiting ubiquitylation processivity and directly interacts with the SCFβ-TrCP E3 ligase complex in a β-TrCP-dependent manner. Oncogenic APC truncation variants, although part of the complex, are functionally impaired. Nonetheless, even the most severely truncated APC variant promotes β-catenin recruitment. These findings exemplify the power of biochemical reconstitution to interrogate the molecular mechanisms of Wnt/β-catenin signaling. |
| Databáze: | OpenAIRE |
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