title: Dystroglycan receptor is involved in integrin activation in intestinal epithelia.
abstract: The dystroglycans (alpha-DG and beta-DG), which play important roles in the formation of basement membranes, have been well studied in skeletal muscle and nerve, but their expression and localization in intestinal epithelial cells has not been previously investigated. Here, we demonstrated that the DG complex, composed of alpha-DG, beta-DG, and utrophin, is specifically expressed in the basolateral membrane of the Caco-2-BBE monolayer. The DG complex coprecipitated with beta(1)-integrin, suggesting a possible interaction among these proteins. In addition, we observed that activation of DG receptors by laminin-1 enhanced the interaction between beta(1)-integrin and laminin-1, whereas activation of DG receptors by laminin-2 reduced the interaction between beta(1)-integrin and laminin-2. Finally, we demonstrated that the intracellular COOH-terminal tail of beta-DG and its binding to the DG binding domain of utrophin are crucial for the interactions between laminin-1/-2 and beta(1)-integrin. Collectively, these novel results indicate that dystroglycans play important roles in the regulation of interactions between intestinal epithelial cells and the extracellular matrix.
authors.affiliation: Department of Medicine, Division of Digestive Diseases, Emory University School of Medicine, Atlanta, Georgia, Atlanta, 30322, USA. dmerlin@emory.edu
authors.forename: Adel
authors.initials: A
authors.lastname: Driss
authors.forename: Laetitia
authors.initials: L
authors.lastname: Charrier
authors.forename: Yutao
authors.initials: Y
authors.lastname: Yan
authors.forename: Vivienne
authors.initials: V
authors.lastname: Nduati
authors.forename: Shanthi
authors.initials: S
authors.lastname: Sitaraman
authors.forename: Didier
authors.initials: D
authors.lastname: Merlin
mesh_terms: D018938:Caco-2 Cells; D049030:Dystroglycans / Q000378:metabolism*; D049028:Dystrophin-Associated Protein Complex / Q000378:metabolism*; D006801:Humans; D019012:Integrin beta1 / Q000378:metabolism*; D007413:Intestinal Mucosa / Q000378:metabolism*; D007797:Laminin / Q000378:metabolism*
chemical_list: D049028:Dystrophin-Associated Protein Complex; D019012:Integrin beta1; D007797:Laminin; D049030:Dystroglycans