title: Identification and characterization of Hedgehog modulator properties after functional coupling of Smoothened to G15.
abstract: The seven-transmembrane receptor Smoothened (Smo) transduces the signal initiated by Hedgehog (Hh) morphogen binding to the receptor Patched (Ptc). We have reinvestigated the pharmacological properties of reference molecules acting on the Hh pathway using various Hh responses and a novel functional assay based on the coexpression of Smo with the alpha subunit of the G15 protein in HEK293 cells. The measurement of inositol phosphate (IP) accumulation shows that Smo has constitutive activity, a response blocked by Ptc which indicates a functional Hh receptor complex. Interestingly, the antagonists cyclopamine, Cur61414, and SANT-1 display inverse agonist properties and the agonist SAG has no effect at the Smo-induced IP response, but converts Ptc-mediated inactive forms of Smo into active ones. An oncogenic Smo mutant does not mediate an increase in IP response, presumably reflecting its inability to reach the cell membrane. These studies identify novel properties of molecules displaying potential interest in the treatment of various cancers and brain diseases, and demonstrate that Smo is capable of signaling through G15.
authors.affiliation: CNRS, Institut de Neurobiologie Alfred Fessard-IFR 2118, UPR9040, Laboratoire de Neurobiologie Cellulaire et Moléculaire, Signal Transduction and Developmental Neuropharmacology team, 1 avenue de la Terrasse, Gif-sur-Yvette F-91198, France.
authors.forename: Christelle
authors.initials: C
authors.lastname: Masdeu
authors.forename: Hélène
authors.initials: H
authors.lastname: Faure
authors.forename: Josée
authors.initials: J
authors.lastname: Coulombe
authors.forename: Angèle
authors.initials: A
authors.lastname: Schoenfelder
authors.forename: André
authors.initials: A
authors.lastname: Mann
authors.forename: Isabelle
authors.initials: I
authors.lastname: Brabet
authors.forename: Jean-Philippe
authors.initials: JP
authors.lastname: Pin
authors.forename: Elisabeth
authors.initials: E
authors.lastname: Traiffort
authors.forename: Martial
authors.initials: M
authors.lastname: Ruat
mesh_terms: D000818:Animals; D018797:Cell Cycle Proteins / Q000502:physiology*; D002460:Cell Line; D002462:Cell Membrane / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000502:physiology*; D004149:Dioxoles / Q000494:pharmacology; D016147:Genes, Tumor Suppressor / Q000502:physiology*; D053823:Hedgehog Proteins; D006801:Humans; D051379:Mice; D009369:Neoplasms / Q000378:metabolism; D010879:Piperazines / Q000494:pharmacology; D011720:Pyrazoles / Q000494:pharmacology; D016601:RNA-Binding Proteins / Q000502:physiology*; D043562:Receptors, G-Protein-Coupled / Q000502:physiology*; D015398:Signal Transduction; D000072086:Smoothened Receptor; D013234:Stem Cells / Q000378:metabolism; D015534:Trans-Activators / Q000502:physiology*; D025521:Tumor Suppressor Proteins / Q000502:physiology*; D014704:Veratrum Alkaloids / Q000494:pharmacology
chemical_list: C474318:CUR 61414; D018797:Cell Cycle Proteins; D004268:DNA-Binding Proteins; D004149:Dioxoles; D053823:Hedgehog Proteins; D010879:Piperazines; D011720:Pyrazoles; C473448:RBM5 protein, human; D016601:RNA-Binding Proteins; D043562:Receptors, G-Protein-Coupled; C468919:SANT-1 compound; C491023:SMO protein, human; D000072086:Smoothened Receptor; D015534:Trans-Activators; D025521:Tumor Suppressor Proteins; D014704:Veratrum Alkaloids; C000541:cyclopamine