The specificity of integrin-ligand interactions in cultured human renal epithelium.

Members of the beta 1 integrin family are present at the basolateral membrane of human renal tubular epithelium in vivo and at the ventral surfaces of cultured renal epithelial cells, at the sites appropriate for cell substratum adhesion. In this study we have proven that these molecules are indeed functional in mediating cell substratum attachment in normal human renal epithelium by using monoclonal antibodies to integrin alpha subunits to block initial cell attachment. The importance of arginine-glycine-aspartic acid (RGD) recognition by cell surface receptors in various extracellular ligands was also examined using synthetic peptides. RGDS peptide strongly inhibited attachment to plain plastic or fibronectin-coated substrata but had no effect on cell adhesion to laminin-coated coverslips.