title: Location of the cell-attachment site in fibronectin with monoclonal antibodies and proteolytic fragments of the molecule.
abstract: Proteolytic fragments of human plasma fibronectin were used to identify monoclonal antibodies reacting with the various domains of fibronectin. One of these antibodies, which reacts with cell-attachment-promoting fragments of fibronectin, inhibits attachment of cells to fibronectin-coated surfaces. A cell-attachment-promoting, chymotryptic, 120 kilodalton fragment was cleaved further with pepsin into three main fragments. The smallest, 15 kilodalton fragment was purified by affinity chromatography on the cell-attachment-inhibiting antibody insolubilized on Sepharose. This fragment is active in promoting cell attachment but lacks the other known binding activities of fibronectin. It can be localized between the collagen-binding and heparin-binding domains, about 127 to 197 kilodaltons from the NH2 terminus of the polypeptide. These results show that the interaction of fibronectin with cells is restricted to a defined portion of the molecule and is independent of the direct involvement of the known affinities toward other macromolecules.
mesh_terms: D000911:Antibodies, Monoclonal / Q000276:immunology; D000918:Antibody Specificity; D001665:Binding Sites; D002462:Cell Membrane / Q000378:metabolism*; D000939:Epitopes; D005353:Fibronectins / Q000276:immunology / Q000378:metabolism*; D066298:In Vitro Techniques; D010446:Peptide Fragments / Q000378:metabolism
chemical_list: D000911:Antibodies, Monoclonal; D000939:Epitopes; D005353:Fibronectins; D010446:Peptide Fragments