title: p120, a p120-related protein (p100), and the cadherin/catenin complex.
abstract: Cadherins and catenins play an important role in cell-cell adhesion. Two of the catenins, beta and gamma, are members of a group of proteins that contains a repeating amino acid motif originally described for the Drosophila segment polarity gene armadillo. Another member of this group is a 120-kD protein termed p120, originally identified as a substrate of the tyrosine kinase pp60src. In this paper, we show that endothelial and epithelial cells express p120 and p100, a 100-kD, p120-related protein. Peptide sequencing of p100 establishes it as highly related to p120. p120 and p100 both appear associated with the cadherin/catenin complex, but independent p120/catenin and p100/catenin complexes can be isolated. This association is shown by coimmunoprecipitation of cadherins and catenins with an anti-p120/p100 antibody, and of p120/p100 with cadherin or catenin antibodies. Immunocytochemical analysis with a p120-specific antibody reveals junctional colocalization of p120 and beta-catenin in epithelial cells. Catenins and p120/p100 also colocalize in endothelial and epithelial cells in culture and in tissue sections. The cellular content of p120/p100 and beta-catenin is similar in MDCK cells, but only approximately 20% of the p120/p100 pool associates with the cadherin/catenin complex. Our data provide further evidence for interactions among the different arm proteins and suggest that p120/p100 may participate in regulating the function of cadherins and, thereby, other processes influenced by cell-cell adhesion.
authors.affiliation: Eisai London Research Laboratories Ltd., University College London, United Kingdom.
authors.forename: J M
authors.initials: JM
authors.lastname: Staddon
authors.forename: C
authors.initials: C
authors.lastname: Smales
authors.forename: C
authors.initials: C
authors.lastname: Schulze
authors.forename: F S
authors.initials: FS
authors.lastname: Esch
authors.forename: L L
authors.initials: LL
authors.lastname: Rubin
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D015820:Cadherins / Q000032:analysis / Q000378:metabolism*; D051177:Catenins; D015815:Cell Adhesion Molecules / Q000032:analysis / Q000378:metabolism*; D002460:Cell Line; D002478:Cells, Cultured; D003598:Cytoskeletal Proteins / Q000032:analysis / Q000378:metabolism*; D004727:Endothelium / Q000737:chemistry* / Q000166:cytology; D004730:Endothelium, Vascular / Q000737:chemistry* / Q000166:cytology; D004847:Epithelial Cells; D004848:Epithelium / Q000737:chemistry*; D006801:Humans; D015151:Immunoblotting; D007150:Immunohistochemistry; D007365:Intercellular Junctions / Q000737:chemistry; D008969:Molecular Sequence Data; D010750:Phosphoproteins / Q000032:analysis / Q000378:metabolism*; D011233:Precipitin Tests; D015534:Trans-Activators; D014407:Tumor Cells, Cultured; D051176:beta Catenin; D000095002:Delta Catenin
chemical_list: C495270:CTNNB1 protein, human; D015820:Cadherins; D051177:Catenins; D015815:Cell Adhesion Molecules; D003598:Cytoskeletal Proteins; D010750:Phosphoproteins; D015534:Trans-Activators; D051176:beta Catenin; D000095002:Delta Catenin; C000722347:CTNND1 protein, human