delta-catenin, an adhesive junction-associated protein which promotes cellscattering

The classical adherens junction that holds epithelial cells together consis ts of a protein complex in which members of the cadherin family linked to v arious catenins are the principal components. delta-catenin is a mammalian brain protein in the Armadillo repeat superfamily with sequence similarity to the adherens junction protein p120(ctn). We found that delta-catenin can be immunoprecipitated as a complex with other components of the adherens j unction, including cadherin and beta-catenin, from transfected cells and br ain. The interaction with cadherin involves direct contact within the highl y conserved juxtamembrane region of the COOH terminus, where p120(ctn) also binds. In developing mouse brain, staining with delta-catenin antibodies i s prominent towards the apical boundary of the neuroepithelial cells in the ventricular zone. When transfected into Madin-Darby canine kidney (MDCK) e pithelial cells delta-catenin colocalized with cadherin, p120(ctn), and bet a-catenin. The Arm domain alone was sufficient for achieving localization a nd coimmunoprecipitation with cadherin. The ectopic expression of delta-cat enin in MDCK cells altered their morphology, induced the elaboration of lam ellipodia, interfered with monolayer formation, and increased scattering in response to hepatocyte growth factor treatment. We propose that delta-cate nin can regulate adhesion molecules to implement the organization of large cellular arrays necessary for tissue morphogenesis.