title: [Interaction of a synthetic fragment of the oncoprotein p21ras with cellular proteins].
abstract: A decapeptide corresponding to residues 35-44(-Thr-Ile-Glu-Asp-Ser-Tyr-Arg-Lys-Gln-Val-) of p21ras was synthesized. It was found that peptide causes precipitation of some proteins from the Triton X-100 lysate of NIH 3T3 EJ cells. SDS-PAGE demonstrated the presence of many proteins in this precipitate. The peptide labeled with [125I]Bolton-Hunter reagent specifically recognized four proteins of M. W. 27, 35, 50 and 85 kDa. The order of charged amino acid residues in the fragment 35-44 of p21ras is "complementary" to that of the substrate sequence of tyrosine-specific protein kinases (-Arg-X-X-Glu-Asp-X-X-Tyr-). It is suggested that p21ras proteins directly regulate phosphorylation of the target proteins of these kinases. A model for functioning of p21ras proteins predicts the presence in their structure of certain sites homologous to sequences recognizable by tyrosine-specific kinases. Indeed two such sites are present in the sequences of all p21ras proteins, namely the residues 88-92 and 104-108.
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002460:Cell Line; D019204:GTP-Binding Proteins / Q000378:metabolism; D051379:Mice; D008954:Models, Biological; D008970:Molecular Weight; D009842:Oligopeptides / Q000032:analysis* / Q000138:chemical synthesis; D010766:Phosphorylation; D011505:Protein-Tyrosine Kinases / Q000378:metabolism; D011518:Proto-Oncogene Proteins / Q000032:analysis* / Q000378:metabolism
chemical_list: D009842:Oligopeptides; D011518:Proto-Oncogene Proteins; D011505:Protein-Tyrosine Kinases; D019204:GTP-Binding Proteins
vernacular_title: Vzaimodeĭstvie sinteticheskogo fragmenta onkobelka p21ras s kletochnymi belkami.