1. TrioGEF1 controls Rac- and Cdc42-dependent cell structures through the direct activation of rhoG
- Author
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Cécile Gauthier-Rouvière, Anne Debant, Anne Blangy, Emmanuel Vignal, Philippe Fort, Susanne Schmidt, Centre de recherches de biochimie macromoléculaire (CRBM), Université Montpellier 1 (UM1)-Université Montpellier 2 - Sciences et Techniques (UM2)-IFR122-Centre National de la Recherche Scientifique (CNRS), and Centre National de la Recherche Scientifique (CNRS)-IFR122-Université Montpellier 2 - Sciences et Techniques (UM2)-Université Montpellier 1 (UM1)
- Subjects
rac1 GTP-Binding Protein ,MESH: Signal Transduction ,GTP' ,MESH: Guanosine Diphosphate ,[SDV.BC.BC]Life Sciences [q-bio]/Cellular Biology/Subcellular Processes [q-bio.SC] ,GTPase ,CDC42 ,[SDV.BID.SPT]Life Sciences [q-bio]/Biodiversity/Systematics, Phylogenetics and taxonomy ,Microtubules ,GTP Phosphohydrolases ,MESH: Protein Structure, Tertiary ,0302 clinical medicine ,Genes, Reporter ,Yeasts ,MESH: Animals ,cdc42 GTP-Binding Protein ,MESH: Peptide Fragments ,Cells, Cultured ,Genes, Dominant ,MESH: Mutagenesis ,0303 health sciences ,MESH: Guanosine Triphosphate ,MESH: Microtubules ,MESH: Yeasts ,MESH: Indicators and Reagents ,MESH: Transcription Factors ,Cell biology ,MESH: Luminescent Proteins ,Guanosine Triphosphate ,Signal Transduction ,MESH: Cells, Cultured ,Binding domain ,MESH: GTP Phosphohydrolases ,MESH: Microscopy, Electron, Scanning ,MESH: Rats ,Recombinant Fusion Proteins ,Green Fluorescent Proteins ,[SDV.CAN]Life Sciences [q-bio]/Cancer ,RAC1 ,Protein Serine-Threonine Kinases ,Biology ,MESH: Actins ,MESH: Two-Hybrid System Techniques ,Guanosine Diphosphate ,MESH: Phosphoproteins ,MESH: Protein-Serine-Threonine Kinases ,03 medical and health sciences ,MESH: Green Fluorescent Proteins ,Microtubule ,Two-Hybrid System Techniques ,MESH: Recombinant Fusion Proteins ,Extracellular ,Animals ,030304 developmental biology ,MESH: cdc42 GTP-Binding Protein ,MESH: rac1 GTP-Binding Protein ,MESH: Genes, Reporter ,[SDV.BBM.BM]Life Sciences [q-bio]/Biochemistry, Molecular Biology/Molecular biology ,Cell Biology ,Fibroblasts ,Phosphoproteins ,Actins ,Peptide Fragments ,Protein Structure, Tertiary ,Rats ,Luminescent Proteins ,[SDV.BDD.EO]Life Sciences [q-bio]/Development Biology/Embryology and Organogenesis ,Mutagenesis ,MESH: Fibroblasts ,Microscopy, Electron, Scanning ,Indicators and Reagents ,RhoG ,MESH: Genes, Dominant ,030217 neurology & neurosurgery ,Transcription Factors - Abstract
International audience; Rho GTPases regulate the morphology of cells stimulated by extracellular ligands. Their activation is controlled by guanine exchange factors (GEF) that catalyze their binding to GTP. The multidomain Trio protein represents an emerging class of &Rgr; regulators that contain two GEF domains of distinct specificities. We report here the characterization of Rho signaling pathways activated by the N-terminal GEF domain of Trio (TrioD1). In fibroblasts, TrioD1 triggers the formation of particular cell structures, similar to those elicited by RhoG, a GTPase known to activate both Rac1 and Cdc42Hs. In addition, the activity of TrioD1 requires the microtubule network and relocalizes RhoG at the active sites of the plasma membrane. Using a classical in vitro exchange assay, TrioD1 displays a higher GEF activity on RhoG than on Rac1. In fibroblasts, expression of dominant negative RhoG mutants totally abolished TrioD1 signaling, whereas dominant negative Rac1 and Cdc42Hs only led to partial and complementary inhibitions. Finally, expression of a Rho Binding Domain that specifically binds RhoG(GTP) led to the complete abolition of TrioD1 signaling, which strongly supports Rac1 not being activated by TrioD1 in vivo. These data demonstrate that Trio controls a signaling cascade that activates RhoG, which in turn activates Rac1 and Cdc42Hs.
- Published
- 2000
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