CADHERIN CATENIN COMPLEXES IN MURINE EPIDERMAL-KERATINOCYTES - E-CADHERIN COMPLEXES CONTAINING EITHER BETA-CATENIN OR PLAKOGLOBIN CONTRIBUTE TO STABLE CELL-CELL CONTACTS/

The cadherin/catenin complexes expressed by a murine epidermal keratin ocyte cell line PDV, expressing E- and P-cadherin, have been analysed using a combination of biochemical and confocal microscopy analysis. T wo types of E-cadherin complexes, containing beta-catenin or plakoglob in and alpha-catenin, were detected in PDV cells as in other cell type s, while P-cadherin was mainly detected in complexes containing beta-c atenin and a-catenin in PDV and other murine epidermal keratinocytes, Biotin-labelling studies have shown that both types of E-cadherin comp lexes are present at the surface of confluent cells. Furthermore, conf ocal microscopy analysis indicated that E-cadherin/plakoglobin complex es are located in stable cell-cell contacts at the middle lateral memb ranes and associated with alpha-catenin and the actin cytoskeleton, wi th a similar distribution to that of the E-cadherin/beta-catenin compl exes. In addition, E-cadherin/plakoglobin complexes not associated wit h alpha-categin or the actin cytoskeleton were detected in lower plane s of the lateral contacting membranes as well as E-cadherin nonassocia ted with catenins in the more basal planes. These studies support that in murine epidermal keratinocytes both beta-catenin- and plakoglobin- containing E-cadherin complexes contribute to the maintenance of stabl e cell-cell contacts and suggest a differential role of the plakoglobi n containing complexes in different epithelial cell types.