Tyrosine phosphorylation of a 22-kDa protein is correlated with transformation by Rous sarcoma virus.
Recent studies from this laboratory have identified novel cytoskeletal proteins that are phosphorylated on tyrosine in vivo in Rous sarcoma virus-transformed chick fibroblasts (Glenney, J. R., Jr., and Zokas, L. (1989) J. Cell Biol. 108, 2401-2408). In the present report, the phosphorylation of these proteins was examined in cells expressing the nonmyristylated mutants of src that are not transformed. A good correlation was found between transformation and the tyrosine phosphorylation of a 22-kDa protein. Tyrosine phosphorylation of the 22-kDa protein was reduced more than 95% in cells expressing the nonmyristylated mutants of src. Size fractionation revealed that the 22-kDa phosphoprotein in transformed chick fibroblasts is found in a Mr 150,000 complex. Monoclonal antibodies were used to screen various chicken tissues where the 22-kDa protein was found at high levels in muscle and lung with low levels in epithelial cells and brain. The 22-kDa protein becomes an excellent candidate for a mediator of transformation by the tyrosine kinase class of oncogenes.
Glenney
J R
JR
Lucille P. Markey Cancer Center, Department of Biochemistry, University of Kentucky College of Medicine, Lexington 40536-0093.
D000818:Animals; D000911:Antibodies, Monoclonal; D001358:Avian Sarcoma Viruses / Q000235:genetics*; D002471:Cell Transformation, Neoplastic; D002642:Chick Embryo; D005347:Fibroblasts / Q000378:metabolism; D008970:Molecular Weight; D009154:Mutation; D019814:Myristic Acid; D009227:Myristic Acids / Q000032:analysis; D010750:Phosphoproteins / Q000302:isolation & purification; D010766:Phosphorylation; D019000:Phosphotyrosine; D011505:Protein-Tyrosine Kinases / Q000032:analysis; D011518:Proto-Oncogene Proteins / Q000032:analysis; D016392:Proto-Oncogene Proteins pp60(c-src); D014443:Tyrosine / Q000032:analysis
D000911:Antibodies, Monoclonal; D009227:Myristic Acids; D010750:Phosphoproteins; D011518:Proto-Oncogene Proteins; D019814:Myristic Acid; D019000:Phosphotyrosine; D014443:Tyrosine; D011505:Protein-Tyrosine Kinases; D016392:Proto-Oncogene Proteins pp60(c-src)