Phosphotyrosine-containing 120,000-dalton protein coimmunoprecipitated with pp60v-src from Rous sarcoma virus-transformed mammalian cells.
Serum from rabbits bearing tumors (TBR serum) induced by the Rous sarcoma virus (RSV) was originally developed to identify the RSV src gene protein-pp60v-src. It is also capable of directly or indirectly immunoprecipitating a number of proteins besides pp60v-src from lysates of RSV-transformed cells. This report describes a highly phosphorylated protein of approximately 120,000 Da (pp120) which is specifically immunoprecipitated from RSV-transformed mammalian cells by TBR sera and monospecific antibodies against pp60v-src. However, it was not immunoprecipitated by TBR serum from RSV-transformed chicken embryo fibroblasts. Phosphoamino acid analysis revealed that pp120 contains phosphoserine and phosphotyrosine in relative amounts similar to that found in pp60v-src. Various experimental results indicate that pp120 is not structurally related to RSV virion proteins or to the putative pp60v-src substrate-vinculin. Furthermore, proteolytic peptide mapping and immunoblotting experiments indicate that although pp120 is immunoprecipitated by various anti-pp60v-src antibodies, it does not appear to be related to the RSV transforming protein. These results suggest that pp120 is distinct from previously reported substrates of pp60v-src and may exist in association with the transforming protein in mammalian cell lysates.
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D000818:Animals; D003411:Arvicolinae; D001358:Avian Sarcoma Viruses / Q000032:analysis / Q000502:physiology*; D002460:Cell Line; D002472:Cell Transformation, Viral; D011232:Chemical Precipitation; D002642:Chick Embryo; D000939:Epitopes / Q000032:analysis; D007106:Immune Sera; D051379:Mice; D008970:Molecular Weight; D009124:Muscle Proteins / Q000032:analysis; D015688:Oncogene Protein pp60(v-src); D010750:Phosphoproteins / Q000032:analysis / Q000276:immunology / Q000302:isolation & purification*; D010768:Phosphoserine / Q000032:analysis; D019000:Phosphotyrosine; D012191:Retroviridae Proteins / Q000032:analysis / Q000276:immunology / Q000302:isolation & purification*; D014443:Tyrosine / Q000031:analogs & derivatives / Q000032:analysis; D016596:Vinculin
D000939:Epitopes; D007106:Immune Sera; D009124:Muscle Proteins; D010750:Phosphoproteins; D012191:Retroviridae Proteins; D016596:Vinculin; D010768:Phosphoserine; D019000:Phosphotyrosine; D014443:Tyrosine; D015688:Oncogene Protein pp60(v-src)