Afadin regulates actomyosin organization through alpha E-catenin at adherens junctions

Epithelial cell integrity and remodeling require proper actomyosin organization at adherens junctions through αE-catenin complexed with β-catenin. Sakakibara et al. show that afadin binds to αE-catenin complexed with β-catenin and enhances its F-actin–binding activity in a novel mechanism.
Actomyosin-undercoated adherens junctions are critical for epithelial cell integrity and remodeling. Actomyosin associates with adherens junctions through αE-catenin complexed with β-catenin and E-cadherin in vivo; however, in vitro biochemical studies in solution showed that αE-catenin complexed with β-catenin binds to F-actin less efficiently than αE-catenin that is not complexed with β-catenin. Although a “catch-bond model” partly explains this inconsistency, the mechanism for this inconsistency between the in vivo and in vitro results remains elusive. We herein demonstrate that afadin binds to αE-catenin complexed with β-catenin and enhances its F-actin–binding activity in a novel mechanism, eventually inducing the proper actomyosin organization through αE-catenin complexed with β-catenin and E-cadherin at adherens junctions.