title: Membrane glycoproteins involved in cell--substratum adhesion.
abstract: A combination of immunological and biochemical methods were used to identify surface membrane components involved in cell-substratum adhesion. Broad-spectrum antiserum, prepared against surface membranes from hamster cells, induced reversible rounding and detachment of hamster fibroblasts from a substratum in vitro. This phenomenon was inhibited by Nonidet P-40 extracts of hamster cells. Therefore, an antibody neutralization assay was developed to detect the presence of antigen during the fractionation of Nonidet P-40 extracts of cells. After two differential precipitation steps, anion exchange chromatography, and sequential lectin affinity chromatography, a fraction greatly enriched in ability to block antiserum-induced changes in cell adhesion and appearance was isolated. Analysis of this fraction by NaDodSO4/polyacrylamide gel electrophoresis revealed a highly restricted group of glycoproteins with Mr approximately 140,000. A lectin-purified glycoprotein fraction was used to raise a higher titer antiserum that was able to induce reversible rounding and detachment of cells from a substratum and, when immobilized on an antibody affinity column, was able to bind and release material capable of blocking antiserum-induced cell rounding. These methods have allowed us to focus attention on a restricted group of glycoproteins that are integral constituents of the surface membrane and which play some as yet undetermined role in the process of cell--substratum adhesion.
mesh_terms: D000818:Animals; D000936:Antigen-Antibody Complex; D001358:Avian Sarcoma Viruses / Q000235:genetics; D002448:Cell Adhesion; D002460:Cell Line; D002472:Cell Transformation, Viral; D002846:Chromatography, Affinity; D006224:Cricetinae; D004591:Electrophoresis, Polyacrylamide Gel; D006023:Glycoproteins / Q000302:isolation & purification / Q000502:physiology*; D007106:Immune Sera; D007668:Kidney; D037102:Lectins; D008565:Membrane Proteins / Q000302:isolation & purification / Q000502:physiology*
chemical_list: D000936:Antigen-Antibody Complex; D006023:Glycoproteins; D007106:Immune Sera; D037102:Lectins; D008565:Membrane Proteins