title: The Ron oncogenic activity induced by the MEN2B-like substitution overcomes the requirement for the multifunctional docking site.
abstract: Oncogenic activation of the Ron tyrosine kinase (Macrophage Stimulating Protein receptor) relies on substitutions of two highly conserved residues in the catalytic domain (D1232V and M1254T), which result in ligand-independent activation of the receptor, in vivo tumorigenesis and metastasis. We show here that the Y/F conversion of the Y1317 residue in the kinase domain impairs tumorigenic and metastatic properties of Ron activated by the MEN2B-like mutation (RonM1254T), but not by other two oncogenic substitutions. Furthermore, RonM1254T lacking the multifunctional docking site retains transforming and metastatic activity. These data reveal that the transforming activity of RonM1254T mutant is dependent on Y1317 phosphorylation, suggesting a shift in intramolecular substrate specificity. Consistently, a shift of RonM1254T kinase substrate specificity was observed by in vitro peptide phosphorylation assays and in vivo receptor auto-phosphorylation. The Y1317 phosphorylation elicits by itself activation of PI-3K/Akt and MAPK signalling pathways. Our data indicate that the accomplishment of the full oncogenic phenotype of RonM1254T requires the phosphorylation both of the canonical C-terminal docking site and of the unique Y1317 residue in the tyrosine kinase domain.
authors.affiliation: Dibit-HSR, via Olgettina 58, I-20138, Milano, Italy.
authors.forename: M M
authors.initials: MM
authors.lastname: Santoro
authors.forename: L
authors.initials: L
authors.lastname: Penengo
authors.forename: S
authors.initials: S
authors.lastname: Orecchia
authors.forename: M
authors.initials: M
authors.lastname: Cilli
authors.forename: G
authors.initials: G
authors.lastname: Gaudino
mesh_terms: D002471:Cell Transformation, Neoplastic / Q000235:genetics*; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D018814:Multiple Endocrine Neoplasia Type 2b / Q000235:genetics; D009154:Mutation; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism; D010766:Phosphorylation; D017346:Protein Serine-Threonine Kinases; D011518:Proto-Oncogene Proteins / Q000378:metabolism; D051057:Proto-Oncogene Proteins c-akt; D020794:Receptor Protein-Tyrosine Kinases / Q000235:genetics*; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000235:genetics; D011956:Receptors, Cell Surface / Q000235:genetics*; D011993:Recombinant Fusion Proteins; D015398:Signal Transduction; D013379:Substrate Specificity
chemical_list: D020928:Mitogen-Activated Protein Kinases; D019869:Phosphatidylinositol 3-Kinases; D017346:Protein Serine-Threonine Kinases; D011518:Proto-Oncogene Proteins; D051057:Proto-Oncogene Proteins c-akt; D020794:Receptor Protein-Tyrosine Kinases; D018719:Erb-b2 Receptor Tyrosine Kinases; D011956:Receptors, Cell Surface; D011993:Recombinant Fusion Proteins; C080835:RON protein