title: Contextual binding of p120ctn to E-cadherin at the basolateral plasma membrane in polarized epithelia.
abstract: E-cadherin-catenin complexes mediate cell-cell adhesion on the basolateral membrane of epithelial cells. The cytoplasmic tail of E-cadherin supports multiple protein interactions, including binding of beta-catenin at the C terminus and of p120ctn to the juxtamembrane domain. The temporal assembly and polarized trafficking of the complex or its individual components to the basolateral membrane are not fully understood. In Madin-Darby canine kidney cells at steady state and after treatment with cycloheximide or temperature blocks, E-cadherin and beta-catenin localized to the Golgi complex, but p120ctn was found only at the basolateral plasma membrane. We previously identified a dileucine sorting motif (Leu586-Leu587, termed S1) in the juxtamembrane domain of E-cadherin and now show that it is required to target full-length E-cadherin to the basolateral membrane. Removal of S1 resulted in missorting of E-cadherin mutants (EcadDeltaS1) to the apical membrane; beta-catenin was simultaneously missorted and appeared at the apical membrane. p120ctn was not mistargeted with EcadDeltaS1, but could be recruited to the E-cadherin-catenin complex only at the basolateral membrane. These findings help define the temporal assembly and sorting of the E-cadherin-catenin complex and show that membrane recruitment of p120ctn in polarized cells is contextual and confined to the basolateral membrane.
authors.affiliation: Institute for Molecular Bioscience, School of Molecular and Microbial Sciences, University of Quensland, Brisbane, 4072 Queensland, Australia.
authors.forename: Kevin C
authors.initials: KC
authors.lastname: Miranda
authors.forename: Shannon R
authors.initials: SR
authors.lastname: Joseph
authors.forename: Alpha S
authors.initials: AS
authors.lastname: Yap
authors.forename: Rohan D
authors.initials: RD
authors.lastname: Teasdale
authors.forename: Jennifer L
authors.initials: JL
authors.lastname: Stow
mesh_terms: D020816:Amino Acid Motifs; D000818:Animals; D016466:CHO Cells; D051177:Catenins; D015815:Cell Adhesion Molecules / Q000737:chemistry* / Q000378:metabolism; D002460:Cell Line; D002462:Cell Membrane / Q000378:metabolism*; D016764:Cell Polarity; D003001:Cloning, Molecular; D006224:Cricetinae; D003513:Cycloheximide / Q000494:pharmacology; D003598:Cytoskeletal Proteins / Q000378:metabolism; D004285:Dogs; D004847:Epithelial Cells / Q000378:metabolism*; D019084:Fluorescent Antibody Technique, Indirect; D005822:Genetic Vectors; D049452:Green Fluorescent Proteins; D015151:Immunoblotting; D008164:Luminescent Proteins / Q000378:metabolism; D010750:Phosphoproteins / Q000737:chemistry* / Q000378:metabolism; D011233:Precipitin Tests; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D011500:Protein Synthesis Inhibitors / Q000494:pharmacology; D013696:Temperature; D013997:Time Factors; D015534:Trans-Activators / Q000378:metabolism; D051176:beta Catenin; D000095002:Delta Catenin
chemical_list: D051177:Catenins; D015815:Cell Adhesion Molecules; D003598:Cytoskeletal Proteins; D008164:Luminescent Proteins; D010750:Phosphoproteins; D011500:Protein Synthesis Inhibitors; D015534:Trans-Activators; D051176:beta Catenin; D049452:Green Fluorescent Proteins; D003513:Cycloheximide; D000095002:Delta Catenin