title: Self-contact elimination by membrane fusion.
abstract: Mutual, homophilic cell-cell adhesion between epithelial cells is required for proper maintenance of epithelial barrier function. Whereas opposing membranes from neighboring cells rapidly assemble junctional complexes, self-contacting membranes curiously do not, suggesting that cells have the ability to prevent the maturation of self-junctions. Using a self-contact-inducing microfabricated substrate, we show that self-contacts of normal epithelial cells are rapidly eliminated by membrane fusion between two opposing plasma membranes of a single cell. This membrane fusion is most frequently observed in E-cadherin-expressing epithelial cells, but not in fibroblasts. The efficiency of self-contact elimination depends on extracellular calcium concentration and the level of E-cadherin, suggesting that E-cadherin, although not required, enhances membrane fusion efficiency by bringing opposing membranes into close apposition to one another. Additionally, Rho-associated protein kinase inhibition decreases self-contact-induced membrane fusion of epithelial cells, suggesting that this fusion may be mechanically regulated through the actin-myosin network. This self-contact-induced membrane fusion is a key elimination mechanism for unwanted self-junctions and may be a feature of cell self-recognition.
authors.affiliation: Department of Biomedical Engineering, University of California, Davis, CA 95616.
authors.forename: Grant M
authors.initials: GM
authors.lastname: Sumida
authors.forename: Soichiro
authors.initials: S
authors.lastname: Yamada
mesh_terms: D016475:3T3 Cells; D000818:Animals; D015820:Cadherins / Q000378:metabolism*; D004285:Dogs; D004847:Epithelial Cells / Q000502:physiology*; D006801:Humans; D007365:Intercellular Junctions / Q000502:physiology; D061986:MCF-7 Cells; D061985:Madin Darby Canine Kidney Cells; D008561:Membrane Fusion / Q000502:physiology*; D051379:Mice; D018613:Microscopy, Confocal; D009841:Oligonucleotides / Q000235:genetics; D054460:rho-Associated Kinases / Q000378:metabolism
chemical_list: D015820:Cadherins; D009841:Oligonucleotides; D054460:rho-Associated Kinases
keywords: contractility; seamless tubule; soft lithography