title: RhoA/ROCK activation by growth hormone abrogates p300/histone deacetylase 6 repression of Stat5-mediated transcription.
abstract: We demonstrate here that growth hormone (GH) stimulates the activation of RhoA and its substrate Rho kinase (ROCK) in NIH-3T3 cells. GH-stimulated formation of GTP-bound RhoA requires JAK2-dependent dissociation of RhoA from its negative regulator p190 RhoGAP. Inactivation of RhoA does not affect GH-stimulated JAK2 tyrosine phosphorylation nor p44/42 MAPK activity. However, RhoA and ROCK activities are required for GH-stimulated, Stat5-mediated transcription. RhoA-dependent enhancement of GH-stimulated, Stat5-mediated transcription is due to repression of histone deacetylase 6 activity recruited by transcription cofactor p300 that negatively regulates GH-stimulated, Stat5-mediated transcription. We also demonstrate that RhoA is the pivot for cAMP-dependent protein kinase inhibition of GH-stimulated, Stat5-mediated transcription as a consequence of cAMP-dependent protein kinase inactivation of RhoA through serine residue 188 of RhoA. We have therefore provided a novel mechanism by which a Ras-like small GTPase, RhoA, can regulate Stat5-mediated transcription.
authors.affiliation: Institute of Molecular and Cell Biology, 30 Medical Drive, Singapore 117609, Republic of Singapore.
authors.forename: Ling
authors.initials: L
authors.lastname: Ling
authors.forename: Peter E
authors.initials: PE
authors.lastname: Lobie
mesh_terms: D000818:Animals; D015153:Blotting, Western; D002455:Cell Division; D002467:Cell Nucleus / Q000378:metabolism; D000242:Cyclic AMP / Q000378:metabolism; D004247:DNA / Q000378:metabolism; D004789:Enzyme Activation; D017930:Genes, Reporter; D005822:Genetic Vectors; D013006:Growth Hormone / Q000378:metabolism; D000073864:Histone Deacetylase 6; D006655:Histone Deacetylases / Q000378:metabolism*; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins; D053614:Janus Kinase 2; D008156:Luciferases / Q000378:metabolism; D051379:Mice; D008856:Microscopy, Fluorescence; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D008954:Models, Biological; D041681:NIH 3T3 Cells; D010766:Phosphorylation; D011233:Precipitin Tests; D011485:Protein Binding; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism*; D011505:Protein-Tyrosine Kinases / Q000378:metabolism; D011518:Proto-Oncogene Proteins; D011994:Recombinant Proteins / Q000737:chemistry; D050799:STAT5 Transcription Factor; D012694:Serine / Q000737:chemistry; D013997:Time Factors; D014158:Transcription, Genetic; D054460:rho-Associated Kinases; D020742:rhoA GTP-Binding Protein / Q000378:metabolism*
chemical_list: D047908:Intracellular Signaling Peptides and Proteins; D011518:Proto-Oncogene Proteins; D011994:Recombinant Proteins; D050799:STAT5 Transcription Factor; C494093:Stat5a protein, mouse; D012694:Serine; D013006:Growth Hormone; D004247:DNA; D000242:Cyclic AMP; D008156:Luciferases; D011505:Protein-Tyrosine Kinases; C507924:JAK2 protein, human; C507926:Jak2 protein, mouse; D053614:Janus Kinase 2; D017346:Protein Serine-Threonine Kinases; D054460:rho-Associated Kinases; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases; C433811:HDAC6 protein, human; C499033:Hdac6 protein, mouse; D000073864:Histone Deacetylase 6; D006655:Histone Deacetylases; D020742:rhoA GTP-Binding Protein