title: Cadherin exits the junction by switching its adhesive bond.
abstract: The plasticity of cell-cell adhesive structures is crucial to all normal and pathological morphogenetic processes. The molecular principles of this plasticity remain unknown. Here we study the roles of two dimerization interfaces, the so-called strand-swap and X dimer interfaces of E-cadherin, in the dynamic remodeling of adherens junctions using photoactivation, calcium switch, and coimmunoprecipitation assays. We show that the targeted inactivation of the X dimer interface blocks the turnover of catenin-uncoupled cadherin mutants in the junctions of A-431 cells. In contrast, the junctions formed by strand-swap dimer interface mutants exhibit high instability. Collectively, our data demonstrate that the strand-swap interaction is a principal cadherin adhesive bond that keeps cells in firm contact. However, to leave the adherens junction, cadherin reconfigures its adhesive bond from the strand swap to the X dimer type. Such a structural transition, controlled by intercellular traction forces or by lateral cadherin alignment, may be the key event regulating adherens junction dynamics.
authors.affiliation: Department of Dermatology, The Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA.
authors.forename: Soonjin
authors.initials: S
authors.lastname: Hong
authors.forename: Regina B
authors.initials: RB
authors.lastname: Troyanovsky
authors.forename: Sergey M
authors.initials: SM
authors.lastname: Troyanovsky
mesh_terms: D022005:Adherens Junctions / Q000378:metabolism*; D000818:Animals; D015820:Cadherins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D002118:Calcium / Q000378:metabolism; D002448:Cell Adhesion / Q000502:physiology*; D006801:Humans; D055503:Protein Multimerization; D020836:Protein Structure, Quaternary; D017434:Protein Structure, Tertiary; D014407:Tumor Cells, Cultured
chemical_list: D015820:Cadherins; D002118:Calcium