Structure and function of macrophage adhesion molecule examined by epitope mapping.
Macrophage adhesion molecule (MAM), a member of the integrin superfamily of heterodimer membrane molecules with adhesive properties, is the guinea pig counterpart of human Mo1 (CD11b/CD18). Earlier work showed that MAM is synthesized as monomeric precursor glycopeptides that assemble to form the heterodimer. The heterodimer and monomer glycopeptides are characterized through the use of twelve mAb in immunoprecipitation, immunoblotting, binding assays, and a quantitative cell adhesion assay. Seven topographic regions are identified, two of which are shown to be critical for adhesion. One adhesion-related topographic region, the M2/M4 region, is on the alpha-subunit, and the other, the M8/M15 region, is on the beta-subunit. Both adhesion-related epitopic regions are not detectable on monomeric glycopeptides but are generated by conformational change on heterodimer formation. It is hypothesized that these structure-function relationships have general applicability to integrin molecules.
Remold-O'Donnell
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Center for Blood Research, Harvard Medical School, Boston, MA 02115.
D000818:Animals; D000911:Antibodies, Monoclonal; D000937:Antigen-Antibody Reactions; D000954:Antigens, Surface / Q000276:immunology / Q000302:isolation & purification*; D002448:Cell Adhesion; D015815:Cell Adhesion Molecules; D003101:Collodion; D004591:Electrophoresis, Polyacrylamide Gel; D000939:Epitopes / Q000276:immunology / Q000302:isolation & purification*; D006168:Guinea Pigs; D008264:Macrophages / Q000032:analysis* / Q000276:immunology / Q000502:physiology; D008297:Male; D051379:Mice; D010449:Peptide Mapping; D011233:Precipitin Tests; D011498:Protein Precursors / Q000276:immunology / Q000302:isolation & purification; D013329:Structure-Activity Relationship
D000911:Antibodies, Monoclonal; D000954:Antigens, Surface; D015815:Cell Adhesion Molecules; D000939:Epitopes; D011498:Protein Precursors; D003101:Collodion