title: Biochemical analysis of claudin-binding compatibility.
abstract: Tissue barrier function is directly mediated by tight junction transmembrane proteins known as claudins. Cells that form tight junctions typically express multiple claudin isoforms, which suggests that heterotypic (head-to-head) binding between different claudin isoforms may play a role in regulating paracellular permeability. To test whether claudins are heterotypically compatible, we developed an assay system using HeLa cells, a claudin-null cell line which expresses other tight junction proteins, including occludin, junction adhesion molecule A, and zonula occludens-1, -2, and -3. HeLa cells stably transfected to express different claudins are cocultured, then subsequently analyzed for the ability to coimmunopurify. Using this approach, we have found that claudin-1, claudin-3, and claudin-5 are heterotypically compatible. In contrast, two closely related claudins, claudin-3 and claudin-4, are incompatible. Differential claudin-binding specificity is likely to have downstream effects on the regulation of tight junction composition and permeability.
authors: Christina
authors: C
authors: Ward
authors: Michael
authors: M
authors: Koval
mesh_terms: D057167:Claudins / Q000302:isolation & purification / Q000378:metabolism*; D004591:Electrophoresis, Polyacrylamide Gel / Q000379:methods; D006367:HeLa Cells; D006801:Humans; D015151:Immunoblotting / Q000379:methods; D008856:Microscopy, Fluorescence / Q000379:methods; D010539:Permeability; D011485:Protein Binding; D020033:Protein Isoforms / Q000378:metabolism*; D019108:Tight Junctions / Q000378:metabolism*; D014162:Transfection / Q000379:methods
chemical_list: D057167:Claudins; D020033:Protein Isoforms