Recruitment of beta-catenin to cadherin-mediated intercellular adhesions is involved in myogenic induction.

Cadherin-mediated cell adhesion is involved in muscle differentiation from early stages of myogenic induction to late stages of myoblast interaction and fusion. beta-Catenin is a major constituent of cadherin-based adherens junctions and also serves as a signal transduction molecule that regulates gene expression during development. In this study, we explored the involvement of beta-catenin in myogenic differentiation. We show here that shortly after a switch from growth to differentiation medium, beta-catenin translocates to cell-cell junctions and its levels increase. We further show that elevation of beta-catenin levels, induced either by inhibition of its breakdown, using LiCl, or by its overexpression, suppresses the formation of adherens junctions, resulting in a sharp decline in myogenin expression and an arrest of myogenic progression. Recruitment of beta-catenin to adherens junctions after transfection with N-cadherin restores myogenin expression in the transfected cells. These results suggest that increased cadherin-mediated adhesion and translocation of beta-catenin to adherens junctions are involved in activating the early steps of myogenic differentiation.