Topography of N-CAM structural and functional determinants. I. Classification of monoclonal antibody epitopes.
12 distinct neural cell adhesion molecule (N-CAM) epitopes, each recognized by a different monoclonal antibody (mAb), have been characterized in terms of the major structural and functional features of the molecule. Seven antibodies, each recognizing the amino-terminal region of the molecule, altered the rate of N-CAM-mediated adhesion. Four of these were inhibitors, two of which also recognized a heparin-binding N-CAM fragment. The other three antibodies specifically enhanced the rate of N-CAM-mediated adhesion. Three epitopes, one polypeptide- and two carbohydrate-dependent, were associated with the sialic acid-rich central portion of the molecule. The remaining two antibodies were found to react with intracellular determinants, and are specific for the largest of the three major N-CAM polypeptide forms. Studies on the ability of one antibody to hinder recognition of native N-CAM by another antibody suggested that the epitopes associated with N-CAM binding functions are in close proximity compared with the other determinants. The classification of these mAb epitopes has allowed the topographical placement of key N-CAM features, as described in the following paper, and provides valuable probes for analysis of both the structure and function of N-CAM.
D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology*; D000954:Antigens, Surface / Q000276:immunology*; D001667:Binding, Competitive; D002448:Cell Adhesion; D015815:Cell Adhesion Molecules; D002462:Cell Membrane / Q000276:immunology; D003593:Cytoplasm / Q000276:immunology; D000939:Epitopes; D005110:Extracellular Space / Q000276:immunology; D006023:Glycoproteins / Q000276:immunology*; D006493:Heparin / Q000276:immunology; D066298:In Vitro Techniques; D008565:Membrane Proteins / Q000276:immunology*; D010446:Peptide Fragments / Q000276:immunology; D012160:Retina / Q000276:immunology; D012795:Sialoglycoproteins / Q000276:immunology
D000911:Antibodies, Monoclonal; D000954:Antigens, Surface; D015815:Cell Adhesion Molecules; D000939:Epitopes; D006023:Glycoproteins; D008565:Membrane Proteins; D010446:Peptide Fragments; D012795:Sialoglycoproteins; D006493:Heparin