Project description:Glucocorticoids (GCs) bind to the glucocorticoid receptor (GR) to regulate diverse biological functions from cell growth to apoptosis. Drugs that mimic their action are the most commonly prescribed therapeutic agents in the world and are currently used for the treatment of many diseases including asthma, autoimmune disorders, and some cancers. However, the mechanisms by which one hormone, via one receptor, modulates such diverse biological functions remain unclear. We hypothesized that epigenetic alteration to the GR may contribute to its signaling diversity, and here we demonstrate that Glycogen Synthase Kinase-3-beta phosphorylates GR on Serine 404 in a glucocorticoid-dependent manner. U-2 OS cells expressing a mutant GR that is incapable of Ser404 phosphorylation have enhanced global transcriptional responses, stronger NF-kappaB transrepression, and enhanced cell death in response to dexamethasone. Conversely, presence of Ser404 phosphorylation on the GR inhibits glucocorticoid-dependent NF-kappaB transrepression and cell death of these osteoblasts. Collectively, our results describe a novel convergence point of the GSK-3-beta pathway with the GR resulting in altered glucocorticoid regulated signaling. Our results also provide a mechanism by which the phosphorylation status of Ser404 in GR can dictate how cells will ultimately respond to GCs. Keywords: Glucocorticoid Receptor; GSK-3-beta; NF-kappaB Transrepression; Phosphorylation
Project description:This study investigates STK39 (Serine/Threonine Kinase 39)-dependent phosphorylation of GSK3B (Glycogen Synthase Kinase 3 Beta) using affinity purification coupled with mass spectrometry.
Project description:Adenosine 5’ monophosphate-activated protein kinase regulates metabolic actions of glucocorticoids by phosphorylating the glucocorticoid receptor through p38 mitogen-activated protein kinase.
Project description:Here, we report synergistic inhibition of glycogen synthase kinase 3 (GSK3), transforming growth factor β (TGF β), and Notch signaling pathways by small molecules can efficiently convert monolayer cultured hESCs into homogenous primitive neuroepithelium within one week under chemically defined condition. These primitive neuroepithelia can stably self-renew in the presence of leukemia inhibitory factor, GSK3 inhibitor (CHIR99021) and TGF β receptor inhibitor (SB431542); retain high neurogenic potential and responsiveness to instructive neural patterning cues toward midbrain and hindbrain neuronal subtypes; and exhibit in vivo integration. hESCs at about 20% confluence were treated with 3 μM CHIR99021, 2 μM SB431542, 0.1 μM Compound E (γ-Secretase Inhibitor XXI) in neural induction media containing Advanced DMEM/F12:Neurobasal (1:1), 1xN2, 1xB27, 1% Glutmax, 5 μg/ml BSA and 10 ng/ml hLIF, for 7 days. The culture was then split 1:3 for the next six passages using Accutase and cultured in neural induction media supplemented with 3 μM CHIR99021 and 2 μM SB431542 on X-ray inactivated MEF feeders or Matrigel-coated plates. After six passages, the cells were split 1:10 regularly. Global gene expression analysis of primitive neural stem cells
Project description:Glucocorticoids play central roles in the regulation of energy metabolism by shifting it toward catabolism, while AMPK is the master regulator of energy homeostasis, sensing energy depletion and stimulating pathways of increasing fuel uptake and saving on peripheral supplies. We showed here that AMPK regulates glucocorticoid actions on carbohydrate metabolism by targeting the glucocorticoid receptor (GR) and modifying transcription of glucocorticoid-responsive genes in a tissue- and promoter-specific fashion. Activation of AMPK in rats reversed glucocorticoid-induced hepatic steatosis and suppressed glucocorticoid-mediated stimulation of glucose metabolism. Transcriptomic analysis in the liver suggested marked overlaps between the AMPK and glucocorticoid signaling pathways directed mostly from AMPK to glucocorticoid actions. AMPK accomplishes this by phosphorylating serine 211 of the human GR indirectly through phosphorylation and consequent activation of p38 MAPK and by altering attraction of transcriptional coregulators to DNA-bound GR. In human peripheral mononuclear cells, AMPK mRNA expression positively correlated with that of glucocorticoid-responsive GILZ, which correlated also positively with the body mass index of subjects. These results indicate that the AMPK-mediated energy control system modulates glucocorticoid action at target tissues. Since increased action of glucocorticoids is associated with development of metabolic disorders, activation of AMPK could be a promising target for developing pharmacologic interventions to these pathologies. We tested the hypothesis by treateing rats with the synthetic glucocorticoid dexamethasone and the AMPK activator 5-aminoimidazole-4-carboxamide-1-β-d-ribonucleoside (AICAR).
Project description:Developmental regulator RUNX3 targets MYC protein for rapid degradation through the glycogen synthase kinase-3 beta-box/WD repeat-containing protein 7 (GSK3β-FBXW7) proteolytic pathway. We therefore uncover a previously unknown mode of MYC destabilization by RUNX3 and provide an explanation as to why RUNX3 inhibits early-stage cancer development in gastrointestinal and lung mouse cancer models.
Project description:Analysis of genes induced by 2I condition 2i contains glycogen synthase kinase 3 (GSK3) and mitogen-activated protein kinase kinase (MEK) inhibitors: 3uM Chir99021 and 1uM PD0325901 Total RNA obtained from B6 mESCs treated with LIF or LIF/2I for 12 hours.
