title: The tyrosine phosphatase Shp-2 mediates intracellular signaling initiated by Ret mutants.
abstract: The Src homology 2-containing tyrosine phosphatase, Shp-2, is a crucial enzyme that mediates intracellular signaling and is implicated in cell proliferation and differentiation. Here we investigated the involvement of the Shp-2 tyrosine phosphatase in determining the downstream signaling pathways initiated by the Ret oncogene, carrying either the cysteine 634 to tyrosine or the methionine 918 to threonine substitutions. These mutations convert the receptor tyrosine kinase, Ret, into a dominant transforming protein and induce constitutive activation of its intrinsic tyrosine kinase activity leading to congenital and sporadic cancers in neuroendocrine organs. Using the PC12, rat pheochromocytoma cell line, as model system, we show that Shp-2 mediates immediate-early gene expression if induced by either of the mutant alleles. Furthermore, we show that Shp-2 activity is required for RetM918T-induced Akt activation. The results indicate that Shp-2 is a downstream mediator of the mutated receptors RetC634Y and RetM918T, thus suggesting that it may act as a limiting factor in Ret-associated endocrine tumors, in the neoplastic syndromes multiple endocrine neoplasia types 2A and 2B.
authors.affiliation: Oncologia Sperimentale E, Istituto Nazionale Tumori, Fondazione G. Pascale, 80131 Naples, Italy.
authors.forename: A
authors.initials: A
authors.lastname: D'Alessio
authors.forename: D
authors.initials: D
authors.lastname: Califano
authors.forename: M
authors.initials: M
authors.lastname: Incoronato
authors.forename: G
authors.initials: G
authors.lastname: Santelli
authors.forename: T
authors.initials: T
authors.lastname: Florio
authors.forename: G
authors.initials: G
authors.lastname: Schettini
authors.forename: M S
authors.initials: MS
authors.lastname: Carlomagno
authors.forename: L
authors.initials: L
authors.lastname: Cerchia
authors.forename: V
authors.initials: V
authors.lastname: de Franciscis
mesh_terms: D000818:Animals; D002454:Cell Differentiation / Q000502:physiology; D002460:Cell Line; D002470:Cell Survival / Q000502:physiology; D051100:Glial Cell Line-Derived Neurotrophic Factor; D007425:Intracellular Membranes / Q000502:physiology*; D047908:Intracellular Signaling Peptides and Proteins; D009154:Mutation / Q000502:physiology*; D009414:Nerve Growth Factors / Q000378:metabolism; D015513:Oncogene Proteins / Q000235:genetics* / Q000378:metabolism; D016716:PC12 Cells / Q000473:pathology; D054592:Protein Tyrosine Phosphatase, Non-Receptor Type 11; D017027:Protein Tyrosine Phosphatases / Q000378:metabolism*; D051096:Proto-Oncogene Proteins c-ret; D051381:Rats; D020794:Receptor Protein-Tyrosine Kinases / Q000235:genetics* / Q000378:metabolism; D015398:Signal Transduction / Q000502:physiology*
chemical_list: C495041:Gdnf protein, rat; D051100:Glial Cell Line-Derived Neurotrophic Factor; D047908:Intracellular Signaling Peptides and Proteins; D009414:Nerve Growth Factors; D015513:Oncogene Proteins; D051096:Proto-Oncogene Proteins c-ret; C099282:RET protein, human; D020794:Receptor Protein-Tyrosine Kinases; C516724:PTPN11 protein, human; D054592:Protein Tyrosine Phosphatase, Non-Receptor Type 11; D017027:Protein Tyrosine Phosphatases; C516727:Ptpn11 protein, rat