P- and E-cadherin are in separate complexes in cells expressing both cadherins

E- and P-cadherin are members of a family of calcium-dependent, cell surface glycoproteins involved in cell-cell adhesion. Extracellularly, the transmembrane cadherins self-associate, while intracellularly, they interact with the actin-based cytoskeleton. Several intracellular proteins, collectively termed catenins, are tightly associated with E- and P-cadherin. These proteins appear to link the cadherin to the cytoskeleton and have been proposed to be involved in concentrating cadherins at cell-cell adherens junctions. In this paper we report the production of monoclonal antibodies against both alpha- and beta-catenin and use these antibodies to show that in cells simultaneously expressing two different cadherins, E-cadherin and P-cadherin, each cadherin appears to be present in a separate cadherin/catenin complex.