title: alpha-Actinin localization in the junctional complex of intestinal epithelial cells.
abstract: We have used antibody to chicken gizzard alpha-actinin to identify and localize this molecule in chicken intestinal epithelium. The antibody binds only to alpha-actinin when tested against a crude extract of chicken gizzard. Extracts of purified epithelial cells contain a molecule which has a subunit molecular weight of 100,000 on sodium dodecyl sulphate gels and which is able to inhibit the interaction of alpha-actinin antibody and 125I-labeled chicken gizzard alpha-actinin. By indirect immunofluorescence, alpha-actinin is localized in the apical portion of chicken intestinal epithelial cells. Ethanol-fixed cryostat sections of intestine taken through the apical portion of the epithelial cells and in a plane perpendicular to the long axis of the cells show that alpha-actinin is organized in a polygonal pattern which corresponds to the outlines of the polygonally packed epithelial cells. We interpret the data as indicating that alpha-actinin is a component of the tight junction (zonula occludens) and/or the belt desmosome (zonula adherens), both of which are membrane structures known to encircle the cell and to be confined to its apical portion.
mesh_terms: D000185:Actinin / Q000032:analysis*; D000818:Animals; D002645:Chickens; D003896:Desmosomes / Q000032:analysis; D005455:Fluorescent Antibody Technique; D007365:Intercellular Junctions / Q000032:analysis*; D007413:Intestinal Mucosa / Q000032:analysis* / Q000648:ultrastructure; D009124:Muscle Proteins / Q000032:analysis*
chemical_list: D009124:Muscle Proteins; D000185:Actinin