title: Specific inhibition of tyrosine kinase activity by an antibody to the v-ros oncogene product.
abstract: Antibodies present in two peritoneal exudates of rats bearing abdominal tumors induced by UR2-transformed rat cells were characterized. The ability to immunoprecipitate p68gag-ros and to inhibit the protein and phospholipid kinase activities of this protein was investigated. One of the exudates specifically inhibited tyrosyl phosphorylation by p68gag-ros but not the activity of other known tyrosyl kinases, such as p150gag-fps of UR1 avian sarcoma virus, p60src, and the insulin receptor. It precipitated p68gag-ros but not Pr76 or other gag-related proteins from UR2-infected cells. Phosphorylation of phosphatidylinositol was not affected by this exudate, suggesting that this activity is not intrinsic to p68gag-ros. Another exudate precipitated p68gag-ros but not gag-related proteins from UR2-infected cells or p140gag-fps from Fujinami sarcoma virus-infected cells. These results demonstrated that the antibodies in these exudates recognized epitopes present in the ros portion of the fused protein p68gag-ros, but only one of the two exudates inhibited the intrinsic tyrosyl kinase of p68gag-ros.
mesh_terms: D000818:Animals; D000906:Antibodies / Q000276:immunology; D001358:Avian Sarcoma Viruses / Q000235:genetics*; D002472:Cell Transformation, Viral; D002478:Cells, Cultured; D002642:Chick Embryo; D000939:Epitopes; D009856:Oncogene Proteins, Viral / Q000276:immunology / Q000378:metabolism*; D010766:Phosphorylation; D011505:Protein-Tyrosine Kinases / Q000037:antagonists & inhibitors*; D051381:Rats
chemical_list: D000906:Antibodies; D000939:Epitopes; D009856:Oncogene Proteins, Viral; D011505:Protein-Tyrosine Kinases