Glycogen Synthase Kinase-3β Is Involved in Ligand-Dependent Activation of Transcription and Cellular Localization of the Glucocorticoid Receptor
| Autor: | Lluís Pons-Hernández, Ana M. Cosialls, Francesc Ventura, Alba Pérez-Perarnau, Cristina Moncunill-Massaguer, José M. López, Diana M. González-Gironès, Claudia M. Palmeri, Joan Gil, Daniel Iglesias-Serret, Camila Rubio-Patiño, Gabriel Pons |
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| Jazyk: | angličtina |
| Rok vydání: | 2012 |
| Předmět: |
Chromatin Immunoprecipitation
Indoles Transcription Genetic Cell Survival Blotting Western RNA polymerase II Apoptosis Maleimides Transactivation Glycogen Synthase Kinase 3 Endocrinology Glucocorticoid receptor Receptors Glucocorticoid Gene expression Tumor Cells Cultured Humans Enzyme Inhibitors Molecular Biology GSK3B Transcription factor Original Research Gene knockdown Glycogen Synthase Kinase 3 beta Microscopy Confocal biology Reverse Transcriptase Polymerase Chain Reaction General Medicine Flow Cytometry Molecular biology biology.protein Chromatin immunoprecipitation Protein Binding |
| Popis: | Glucocorticoids (GC) induce cell cycle arrest and apoptosis in different cell types and therefore are widely used to treat a variety of diseases including autoimmune disorders and cancer. This effect is mediated by the GC receptor (GR), a ligand-activated transcription factor that translocates into the nucleus where it modulates transcription of target genes in a promoter-specific manner. Glycogen synthase kinase-3 (GSK3) regulates GR response by genomic and nongenomic mechanisms, although the specific role of each isoform is not well defined. We used GSK3 pharmacological inhibitors and isoform-specific small interfering RNA to evaluate the role of GSK3 in the genomic regulation induced by GC. GSK3 inhibition resulted in the reduction of GC-induced mRNA expression of GC-induced genes such as BIM, HIAP1, and GILZ. Knockdown of GSK3β but not GSK3α reduced endogenous GILZ induction in response to dexamethasone and GR-dependent reporter gene activity. Chromatin immunoprecipitation experiments revealed that GSK3 inhibition impaired the dexamethasone-mediated binding of GR and RNA polymerase II to endogenous GILZ promoter. These results indicate that GSK3β is important for GR transactivation activity and that GSK3β inhibition suppresses GC-stimulated gene expression. Furthermore, we show that genomic regulation by the GR is independent of known GSK3β phosphorylation sites. We propose that GC-dependent transcriptional activation requires functional GSK3β signaling and that altered GSK3β activity influences cell response to GC. |
| Databáze: | OpenAIRE |
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