Cytoskeletal Targets for Viral Transforming Proteins with Tyrosine Protein Kinase Activity

Transformation of cells to a malignant state by viruses and other agents results in alterations of a number of cellular properties. Some of the most obvious changes apparent in transformed cells are morphological. Transformed cells are often rounded, rather than spread, and usually adhere less well to their substratum. These morphological changes are accompanied by dramatic changes in internal cytoskeletal architecture. Transformed cells usually show a marked disruption of actin-containing microfilament bundles (Pollack et al. 1975; Ash et al. 1976; Edelman and Yahara 1976; Wang and Goldberg 1976). The organization of intermediate filaments is also affected by transformation (Hynes and Destree 1978a; Singer et al., this volume). In contrast, the microtubular network, although often found in association with intermediate filaments, is relatively unchanged in most transformed cells (Mautner and Hynes 1977; Singer et al., this volume).