title: Epidermal growth factor receptors associated to cytoskeletal elements of epidermoid carcinoma (A431) cells.
abstract: The structural interaction of the epidermal growth factor (EGF) receptor and the cytoskeleton of A431 cells has been studied using a monoclonal anti-EGF receptor antibody. This has been done with immunogold labeling using a variety of electron microscopical preparation procedures and EGF binding studies. By providing an image of the membrane-associated cytoskeleton, the dry cleavage method reveals a preferential localization of EGF receptors superimposed upon cytoskeletal filaments. The colocalization of gold particles with cytoskeletal filaments is not affected when pre-labeled cells are extracted with the non-ionic detergent Triton X-100, as visualized by dry cleavage. Using surface replication, this treatment results in visualization of the cytoskeleton. In these latter preparations, it is also observed that EGF receptor-coupled gold particles remain associated with cytoskeletal elements. Moreover, Triton extraction performed before immunogold labeling of EGF receptors demonstrates that isolated cytoskeletons contained binding sites for anti-EGF receptor antibodies. Using stereo micrographs of replica's obtained from these isolated cytoskeletons, it is shown that gold-labeled EGF receptors are exclusively present on the cortical membrane-associated region of the cytoskeleton and not on more intracellular-located filaments. Scatchard analysis of EGF binding to cells fixed with glutaraldehyde and treated with Triton X-100 before and after EGF binding indicates that a high affinity EGF binding site is associated with the Triton X-100 insoluble cytoskeleton.
mesh_terms: D000911:Antibodies, Monoclonal; D002294:Carcinoma, Squamous Cell / Q000378:metabolism* / Q000648:ultrastructure; D002460:Cell Line; D003599:Cytoskeleton / Q000378:metabolism*; D066246:ErbB Receptors; D005404:Fixatives; D006801:Humans; D008854:Microscopy, Electron / Q000379:methods; D011092:Polyethylene Glycols; D011956:Receptors, Cell Surface / Q000378:metabolism*
chemical_list: D000911:Antibodies, Monoclonal; D005404:Fixatives; D011956:Receptors, Cell Surface; D011092:Polyethylene Glycols; D066246:ErbB Receptors