Studies on the function of cell surface glycoproteins. II. Possible role of surface glycoproteins in the control of cytoskeletal organization and surface morphology.

Abstract

Immunoglobulin from goat antiserum directed against purified surface membranes from transformed [by Rous sarcoma virus] BHK21/C13 [baby hamster kidney fibroblast] cells (anti-M) were shown to cause both control and transformed hamster cells to round and detach from the substrate. The effects of the antiserum on the cytoskeletal organization and cell surface morphology of control BHK21/C13 cells examined by scanning and transmission electron microscopy were documented. As a result of antiserum-induced rounding, the normally smooth cell surface becomes covered with filopodia and blebs and the organization of all 3 components of the filamentous cytoskeleton is altered. In terms of cell surface morphology and cytoskeletal organization, the cells resemble rounded, postmitotic or trypsinized BHK cells rather than cells treated with anticytoskeletal drugs or lectins. Immunocytochemical and radioimmune assay experiments demonstrated that the rounding reaction induced by anti-M serum results from the specific interaction of antibodies with molecules on the cell surface. Anti-M serum may induce alterations in cytoskeletal organization via a transmembrane signal and cytoskeletal reorganization is probably a fundamental part of the rounding and detachment process.