title: Detection of phosphorylated retTPC oncogene product in cytoplasm.
abstract: The product of the retTPC oncogene, an activated form of the ret proto-oncogene found in human papillary thyroid carcinomas, was identified as a 57-kDa protein (p57retTPC) by Western blotting with a polyclonal antibody raised by an oligopeptide corresponding to the carboxy-terminal region of the ret proto-oncogene product. Subcellular fractionation experiments using NIH3T3 cell transformants induced by the retTPC cDNA showed that p57retTPC was localized in a soluble cytoplasmic fraction, whereas the ret proto-oncogene products expressed in a neuroblastoma cell line were present in a membrane fraction. Immunostaining also demonstrated that p57retTPC is localized in the cytoplasm. Immunoprecipitation with anti-phosphotyrosine antibody followed by Western blotting revealed that p57retTPC is constitutively phosphorylated, whereas the ret proto-oncogene products are not. These findings suggest that p57retTPC has an aberrant tyrosine kinase activity resulting in autophosphorylation associated with change in its location.
authors.affiliation: Carcinogenesis Division, National Cancer Center Research Institute, Tokyo, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Ishizaka
authors.forename: H
authors.initials: H
authors.lastname: Shima
authors.forename: T
authors.initials: T
authors.lastname: Sugimura
authors.forename: M
authors.initials: M
authors.lastname: Nagao
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002291:Carcinoma, Papillary / Q000737:chemistry; D002461:Cell Line, Transformed; D003593:Cytoplasm / Q000737:chemistry; D029721:Drosophila Proteins; D006801:Humans; D051379:Mice; D008969:Molecular Sequence Data; D015514:Oncogene Proteins, Fusion / Q000032:analysis; D000090063:Proto-Oncogene Mas; D011518:Proto-Oncogene Proteins / Q000032:analysis* / Q000276:immunology; D051096:Proto-Oncogene Proteins c-ret; D020794:Receptor Protein-Tyrosine Kinases; D013347:Subcellular Fractions / Q000737:chemistry; D013964:Thyroid Neoplasms / Q000737:chemistry; D014407:Tumor Cells, Cultured
chemical_list: D029721:Drosophila Proteins; C000715470:MAS1 protein, human; D015514:Oncogene Proteins, Fusion; D000090063:Proto-Oncogene Mas; D011518:Proto-Oncogene Proteins; D051096:Proto-Oncogene Proteins c-ret; D020794:Receptor Protein-Tyrosine Kinases; C416649:Ret protein, Drosophila; C494999:Ret protein, mouse