Characterization of the epidermal growth factor receptor and the erbB oncogene product by site-specific antibodies.

Site-specific antibodies to the src-homologous domain (residues 373-383) of the erbB gene product neutralized the tyrosine kinase activity of the epidermal growth factor receptor, suggesting that the region against which the antibodies were directed may be functionally important for the kinase activity. In the immunofluorescence experiment, the site-specific antibodies detected the epidermal growth factor receptor and the erbB gene product only when the cells were permeabilized prior to staining, while monoclonal anti-epidermal growth factor receptor antibody, which recognizes the epidermal growth factor binding domain, gave a positive surface stain with viable nonpermeabilized A431 cells. This result supports the view that the epidermal growth factor binding domain and the src-homologous domain are located at the cell surface and inner face of the plasma membrane, respectively.