Engineering β-catenin-derived peptides for α-catenin binding

The complex formed by the beta-catenin and alpha-catenin adaptor proteins acts as a molecular bridge that enables E-cadherin-based cell-cell adhesion assembly and maintenance in the epithelial tissue. This occurs through the interaction between the intracellular domain of E-cadherin and beta-catenin on the one hand and between F-actin and alpha-catenin on the other hand. In addition to its role in cell-cell adhesion formation, it has been reported that E-cadherin mediates breast cancer cell metastasis to distant organs. Therefore, development of biomaterials such as peptides with ability to modulate the interaction between beta-catenin and alpha-catenin presents an opportunity to modulate cell-cell adhesion. Here, we have performed computational and experimental analysis to develop beta-catenin-derived peptides with the ability to bind alpha-catenin. Specifically, we analyzed the available beta- and alpha-catenin complex structure and identified residues on beta-catenin having potential to form new interactions upon mutation. We tested the wild-type (WT) and mutant beta-catenin-derived peptides for their binding to alpha-catenin using conventional and steered molecular dynamics simulations, revealing an increased interaction of P128E and M131E mutant peptides. We then designed a Bioluminescence Resonance Energy Transfer (BRET)-based assay to monitor binding of the beta-catenin-derived peptides with alpha-catenin, which revealed similar binding affinities of the WT and mutant beta-catenin-derived peptides. Further, expression of the WT and the M131E mutant peptide resulted in a change in the aspect ratio of the cells suggestive of their ability to affect cell-cell adhesion. We envisage that the beta-catenin-derived peptides engineered here will find application in blocking the interaction between beta-catenin and alpha-catenin and, thus, modulate E-cadherin adhesion, which may lead to potential therapeutic avenue in abrogating E-cadherin-mediated metastasis of invasive breast cancer cells.