Multivalent Interaction of Beta-Catenin With its Intrinsically Disordered Binding Partner Adenomatous Polyposis Coli.


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Authors
Rowling, Pamela JE 
Murton, Ben L 
Du, Zhen 
Itzhaki, Laura S 
Abstract

The Wnt signalling pathway plays key roles in cell proliferation, differentiation and fate decisions in embryonic development and maintenance of adult tissues, and the twelve Armadillo (ARM) repeat-containing protein β-catenin acts as the signal transducer in this pathway. Here we investigate the interaction between β-catenin's ARM repeat domain and the intrinsically disordered protein adenomatous polyposis coli (APC). APC is a giant multivalent scaffold that brings together the different components of the so-called "β-catenin destruction complex", which drives β-catenin degradation via the ubiquitin-proteasome pathway. Mutations and truncations in APC, resulting in loss of APC function and hence elevated β-catenin levels and upregulation of Wnt signalling, are associated with numerous cancers including colorectal carcinomas. APC has a long intrinsically disordered region (IDR) that contains a series of 15-residue and 20-residue binding regions for β-catenin. Here we explore the multivalent nature of the interaction of β-catenin with the highest affinity APC repeat, both at equilibrium and under kinetic conditions. We use a combination of single-site substitutions, deletions and insertions to dissect the mechanism of molecular recognition and the roles of the three β-catenin-binding subdomains of APC.

Description
Keywords
adenomatous polyposis coli (APC), armadillo repeat, beta-catenin (β-catenin), fuzzy binding, intrinsically disordered protein, multivalency, protein-protein interaction (PPI)
Journal Title
Front Mol Biosci
Conference Name
Journal ISSN
2296-889X
2296-889X
Volume Title
9
Publisher
Frontiers Media SA