title: Role of TFG sequences outside the coiled-coil domain in TRK-T3 oncogenic activation.
abstract: The TRK-T3 oncoprotein, isolated from a human papillary thyroid tumor, arises from the fusion between the N-terminal domain of the TFG gene and the tyrosine kinase domain of the NTRK1 receptor. The 68 kDa TRK-T3 oncoprotein displays a constitutive tyrosine kinase activity resulting in its capability to transform NIH3T3 cells. The TFG portion of TRK-T3 contains a coiled-coil domain, which mediates protein oligomerization essential for the oncogene constitutive activation, and several consensus sites for protein interaction. In this study, we investigate the role of TFG sequences outside the coiled-coil domain on TRK-T3 activation, We constructed four mutants carrying different deletions of TFG sequences and expressed them in mammalian cells. By performing biochemical and biological assays we demonstrated that all the deleted regions are required for TRK-T3 activation, as they are involved in different mechanisms such as protein processing, formation of stable and/or functional complexes, and possible interaction with other proteins. By constructing site-specific mutants, we demonstrated a crucial role for a PB1 domain and a considerable contribution of an SH2-binding motif in TRK-T3 oncogenic activation. This work establishes an important role for TFG sequences outside the coiled-coil domain in the activation of the thyroid TRK-T3 oncogene.
authors.affiliation: Operative Unit #3, Department of Experimental Oncology, Instituto Nazionale Tumori, Via G Venezian, Milan, Italy.
authors.forename: Emanuela
authors.initials: E
authors.lastname: Roccato
authors.forename: Sonia
authors.initials: S
authors.lastname: Pagliardini
authors.forename: Loredana
authors.initials: L
authors.lastname: Cleris
authors.forename: Silvana
authors.initials: S
authors.lastname: Canevari
authors.forename: Franca
authors.initials: F
authors.lastname: Formelli
authors.forename: Marco A
authors.initials: MA
authors.lastname: Pierotti
authors.forename: Angela
authors.initials: A
authors.lastname: Greco
mesh_terms: D016475:3T3 Cells; D000595:Amino Acid Sequence; D000818:Animals; D002471:Cell Transformation, Neoplastic / Q000235:genetics; D051379:Mice; D008969:Molecular Sequence Data; D009154:Mutation; D009374:Neoplasms, Experimental / Q000209:etiology / Q000235:genetics; D009857:Oncogenes / Q000502:physiology*; D011506:Proteins / Q000737:chemistry / Q000235:genetics*; D020917:Receptor, trkA / Q000235:genetics; D017422:Sequence Analysis, DNA; D017384:Sequence Deletion; D033921:Vesicular Transport Proteins
chemical_list: D011506:Proteins; D020917:Receptor, trkA; C484335:Tfg protein, mouse; D033921:Vesicular Transport Proteins