Identification of the product of two oncogenic rearranged forms of the RET proto-oncogene in papillary thyroid carcinomas

Oncogene. 1992 Nov;7(11):2189-94.

Abstract

In papillary thyroid carcinomas, we have identified two tumor-specific rearrangements of the RET proto-oncogene leading to the formation of different transforming fusion products sharing the tyrosine kinase (tk) domain of the proto-oncogene and designated ptc-1 and ptc-2. We have analysed ptc-1 and ptc-2 products by immunoprecipitation with specific anti-RET antibodies followed by immunoblotting with the same reagent or with antibodies specific for phosphotyrosine (P-tyr) residues. The anti-RET antibodies were reactive with 64-kDa (p64ptc-1) and 81-kDa (p81ptc-2) proteins from lysates of ptc-1 and ptc-2 transformed cells, respectively, and identified two proteins of 140 kDa and 160 kDa from extracts of SK-N-SH, a neuroblastoma cell line previously shown to express two differently glycosylated forms of the normal RET product. The anti P-tyr antibodies, while detecting the same p64ptc-1 and p81ptc-2 proteins from ptc-1 and ptc-2 extracts, did not show any specific band in the neuroblastoma lysates. An additional set of experiments led us to conclude that, whereas the normal product of the RET proto-oncogene is a membrane-associated receptor-like molecule not intrinsically phosphorylated on tyrosine, both oncogenic forms of RET, ptc-1 and ptc-2, are constitutively phosphorylated on tyrosine, display an 'in vitro' autophosphorylation activity, are translocated from the membrane to the cytoplasm and are apparently unaffected by protein kinase C modulation.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • 3T3 Cells
  • Animals
  • Blotting, Western
  • Carcinoma, Papillary / chemistry
  • Carcinoma, Papillary / genetics*
  • Drosophila Proteins*
  • Gene Rearrangement*
  • Humans
  • Mice
  • Phosphorylation
  • Precipitin Tests
  • Protein-Tyrosine Kinases / analysis*
  • Proto-Oncogene Proteins / analysis*
  • Proto-Oncogene Proteins / genetics
  • Proto-Oncogene Proteins c-ret
  • Proto-Oncogenes*
  • Receptor Protein-Tyrosine Kinases*
  • Tetradecanoylphorbol Acetate / pharmacology
  • Thyroid Neoplasms / chemistry
  • Thyroid Neoplasms / genetics*
  • Tyrosine / metabolism

Substances

  • Drosophila Proteins
  • Proto-Oncogene Proteins
  • Tyrosine
  • Protein-Tyrosine Kinases
  • Proto-Oncogene Proteins c-ret
  • Receptor Protein-Tyrosine Kinases
  • Ret protein, Drosophila
  • Ret protein, mouse
  • Tetradecanoylphorbol Acetate