title: The soluble ectodomain of RetC634Y inhibits both the wild-type and the constitutively active Ret.
abstract: Substitution of Cys-634 in the extracellular domain of the Ret tyrosine kinase receptor causes its dimerization and activation of its transforming potential. To gain further insight into the molecular basis leading to Ret activation we purified a mutant protein consisting of the entire ectodomain of the Ret carrying a Cys-634-->Tyr substitution (EC-Ret(C634Y)). The protein is glycosylated, like the native one, and is biologically active. By using an in vitro cell system we show that EC-Ret(C634Y) inhibits the membrane-bound receptor Ret(C634Y), interfering with its dimerization. Furthermore, we demonstrate that EC-Ret(C634Y) competes with the wild-type Ret receptor for ligand binding. The results presented support the notion of the possible involvment of glial cell line-derived neurotrophic factor (GDNF) with multiple endocrine neoplasia type 2A (MEN2A) tumours, and describe a useful tool for generating molecular mimetics directed towards specific mutations of the ret oncogene.
authors.affiliation: Istituto per l'Endocrinologia e l'Oncologia Sperimentale del CNR G. Salvatore, via Pansini 5, 80131 Napoli, Italy.
authors.forename: Laura
authors.initials: L
authors.lastname: Cerchia
authors.forename: Domenico
authors.initials: D
authors.lastname: Libri
authors.forename: Maria Stella
authors.initials: MS
authors.lastname: Carlomagno
authors.forename: Vittorio
authors.initials: V
authors.lastname: de Franciscis
mesh_terms: D019943:Amino Acid Substitution; D000818:Animals; D001667:Binding, Competitive; D002478:Cells, Cultured; D003545:Cysteine / Q000235:genetics; D019281:Dimerization; D051100:Glial Cell Line-Derived Neurotrophic Factor; D051097:Glial Cell Line-Derived Neurotrophic Factor Receptors; D006031:Glycosylation; D006801:Humans; D008024:Ligands; D018813:Multiple Endocrine Neoplasia Type 2a / Q000209:etiology / Q000235:genetics; D009414:Nerve Growth Factors / Q000378:metabolism; D016716:PC12 Cells; D017434:Protein Structure, Tertiary; D011518:Proto-Oncogene Proteins / Q000037:antagonists & inhibitors / Q000235:genetics* / Q000378:metabolism / Q000494:pharmacology*; D051096:Proto-Oncogene Proteins c-ret; D051381:Rats; D020794:Receptor Protein-Tyrosine Kinases / Q000037:antagonists & inhibitors / Q000235:genetics* / Q000378:metabolism / Q000494:pharmacology*; D011994:Recombinant Proteins / Q000235:genetics / Q000494:pharmacology; D012995:Solubility; D014443:Tyrosine / Q000235:genetics
chemical_list: C495039:GDNF protein, human; C495041:Gdnf protein, rat; D051100:Glial Cell Line-Derived Neurotrophic Factor; D051097:Glial Cell Line-Derived Neurotrophic Factor Receptors; D008024:Ligands; D009414:Nerve Growth Factors; D011518:Proto-Oncogene Proteins; D011994:Recombinant Proteins; D014443:Tyrosine; D051096:Proto-Oncogene Proteins c-ret; D020794:Receptor Protein-Tyrosine Kinases; C495001:Ret protein, rat; D003545:Cysteine