BETA-CATENIN MEDIATES THE INTERACTION OF THE CADHERIN CATENIN COMPLEXWITH EPIDERMAL GROWTH-FACTOR RECEPTOR

Catenins mediate the linkage of classical cadherins with actin microfi laments and are part of a higher order protein structure by which cadh erins are connected to other cytoplasmic and transmembrane proteins. T he ratio of actin-bound to free cadherin-catenin complex, which varies depending on the type and growth rate of cells, is thought to be alte red by cellular signals, such as those associated with mitosis, polari zation of cells and growth factors during development. EGF induces an immediate tyrosine phosphorylation of beta-catenin and gamma-catenin ( plakoglobin). We show here an association of the EGF-receptor with the cadherin-catenin complex. Using recombinant proteins we demonstrate t he interaction of EGF-receptor and beta-catenin in in vitro kinase ass ays. This interaction is mediated by the evolutionarily conserved cent ral ''core'' region of beta-catenin. These results suggest that cateni ns represent an important link between EGF-induced signal transduction and cadherin function.