title: Towards a molecular description of cell transformation by avian sarcoma virus.
abstract: The avian sarcoma virus transforming gene product has been identified and partially purified from extracts of transformed cells. It is a phosphoprotein with a relative molecular mass of 60 000 (pp60src) with two major sites of phosphorylation. pp60src appears to be a cyclic-AMP-independent protein kinase as judged by protein phosphorylation with partly purified fractions. The specificity of the phosphorylation observed was judged by inhibition with anti-pp60src IgG but not by normal IgG and by the fact that the protein kinase activity isolated from ts transformation-mutant infected cells was more thermolabile than that from wild-type transformed cells, thus showing more directly the origin of the enzymic activity. A cellular protein substrate of pp60src has been identified as a 34 000 molecular mass protein. These data together suggest that protein phosphorylation by pp60src may be a function of the molecule that plays a major role in transformation.
mesh_terms: D001355:Alpharetrovirus / Q000235:genetics*; D000818:Animals; D002472:Cell Transformation, Viral; D002478:Cells, Cultured; D005814:Genes, Viral; D010750:Phosphoproteins / Q000378:metabolism; D010766:Phosphorylation; D011494:Protein Kinases / Q000235:genetics*; D014443:Tyrosine / Q000378:metabolism
chemical_list: D010750:Phosphoproteins; D014443:Tyrosine; D011494:Protein Kinases