Project description:Transcriptional profiling elucidates the essential role of glycogen synthase kinase 3 to fruiting body formation in Coprinopsis cinerea
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:Glycogen Synthase Kinase-3 (GSK-3) is a constitutively active, ubiquitously expressed protein kinase that regulates multiple signaling pathways. Over 100 putative GSK-3 substrates have been reported in diverse cell types based on in vitro kinase assays or genetic and pharmacological manipulation of GSK-3. Many more have been predicted based on a recurrent GSK-3 consensus motif, but this prediction has not been tested by analyzing the GSK-3 phosphoproteome. We used stable isotope labeling of amino acids in culture (SILAC) and mass spectrometry to analyze the repertoire of GSK-3 dependent substrates in mouse embryonic stem cells (ESCs). A comparison of wild-type and Gsk3a;Gsk3b knockout (DKO) ESCs revealed prominent GSK-3-dependent phosphorylation of multiple splicing factors and regulators of RNA biosynthesis, as well as proteins that regulate transcription, translation, and cell division. We demonstrate direct, GSK-3-dependent phosphorylation of the splicing factors RBM8A and PSF as well as the nucleolar protein NPM1. RNA sequencing to compare the transcriptomes of wild-type and Gsk3 DKO ESCs identified more than 210 genes that are alternatively spliced in a GSK-3-dependent manner, supporting a broad role for GSK-3 in regulating alternative splicing. Overall, this study provides the first unbiased analysis of the GSK-3 phosphoproteome and strong evidence for GSK-3 as a regulator of alternative splicing.
Project description:Anterior tibialis removed from 3-month old muscle glycogen synthase WT or knockout mouse. RNA was extracted using GibcoBRL TRIzol Reagent and a Quiagen RNeasy kit. Targets were produced using standard Affymetrix procedures from about 5ug of total RNA. GSM40057-GSM40063 AND GSM40956. Liver removed from 3-month old muscle glycogen synthase WT or knockout mouse. RNA was extracted using GibcoBRL TRIzol Reagent and a Quiagen RNeasy kit. Targets were produced using standard Affymetrix procedures from about 10ug of total RNA. GSM40064-GSM40071. Medial gastrocnemius removed from 3-month old muscle glycogen synthase WT or knockout mouse. RNA was extracted using GibcoBRL TRIzol Reagent and a Quiagen RNeasy kit. Targets were produced using standard Affymetrix procedures from about 5ug of total RNA. GSM40072-GSM40079. Medial gastrocnemius removed from 8-month old muscle glycogen synthase WT or overexpressing mouse. RNA was extracted using GibcoBRL TRIzol Reagent and a Quiagen RNeasy kit. Targets were produced using standard Affymetrix procedures from about 5ug of total RNA. GSM40080-GSM40089 Keywords: other
Project description:Nuclear myosin 1c (NM1) mediates RNA polymerase I (pol I) transcription activation and cell cycle progression by facilitating PCAF-mediated H3K9 acetylation, but the molecular mechanism by which NM1 is regulated remains unclear. Here, we report that at early G1 the glycogen synthase kinase (GSK) 3β phosphorylates and stabilizes NM1, allowing for NM1 association with the chromatin. Genomic analysis by ChIP-Seq showed that this mechanism occurs on the rDNA as active GSK3β selectively occupies the gene. ChIP assays and transmission electron microscopy in GSK3β-/- mouse embryonic fibroblasts indicated that at G1 rRNA synthesis is suppressed due to decreased H3K9 acetylation leading to a chromatin state incompatible with transcription. We found that GSK3β directly phosphorylates the endogenous NM1 on a single serine residue (Ser-1020) located within the NM1 C-terminus. In G1 this phosphorylation event stabilizes NM1 and prevents NM1 polyubiquitination by the E3 ligase UBR5 and proteasome-mediated degradation. We conclude that GSK3β-mediated phosphorylation of NM1 is required for pol I transcription activation. Examination of GSK3beta with the genome in mouse embryonic fibroblasts
Project description:Human cytomegalovirus (HCMV)has a global distribution and is highly prevalent. HCMV infection has been recognized as a major contributor to neural development abnormalities in embryos and children. However, the underlying mechanisms by which HCMV infection leads to neurological diseases remain incompletely understood. Our study showed that HCMV inhibits neural cell differentiation by affecting the production of adenosine triphosphate (ATP) during neural differentiation. In this work, we found that HCMV infection interferes with the neural differentiation of stem cells from human exfoliated deciduous teeth (SHEDs)and human neuroblastoma cell line (SH-SY5Ys), affects the expression of neural cell markers, and inhibits the axon formation of neural cells. Under neurogenic inductive conditions, HCMV infection of SHEDs and SH-SY5Ys caused an increase in Glycogen synthase kinase-3β(GSK-3β) phosphorylation level and a decrease in GSK-3β phosphatase activity. HCMV infection was shown to inhibits GSK-3β activity, suppresses the level of mitochondrial oxidative phosphorylation in cells, reduces ATP production, impedes energy supply during neural differentiation, and inhibits neural differentiation. Our study sheds light on a molecular mechanism by which crosstalk between protein phosphorylation and oxidative phosphorylation links HCMV infection and neural differentiation and raises a potential strategy for the therapy of congenital HCMV infection.
Project description:The cellular and organismal phenotypic response to a small molecule kinase inhibitor is defined collectively by the inhibitor’s targets and their functions. The selectively of small molecule kinase inhibitors is commonly determined in vitro, using purified kinases and substrates. Recently, competitive chemical proteomics has emerged as a complementary, unbiased, cell-based approach to define the target landscape of kinase inhibitors. Here we evaluated and optimized a competitive multiplexed inhibitor bead mass spectrometry (MIB/MS) platform using cell lysates, live cells and treated mice. Several clinically active kinase inhibitors were profiled, including trametinib, BMS-777607, dasatinib, abemaciclib, and palbociclib. MIB/MS competition analyses of the cyclin-dependent kinase 4 and 6 (CDK4/6) inhibitors abemaciclib, and palbociclib revealed overlapping and unique kinase targets. Competitive MIB/MS analysis of abemaciclib revealed 83 target kinases, and dose-response profiling revealed glycogen synthase kinase 3 alpha and beta (GSK3 and GSK3 were the most potently inhibited. Cell based and in vitro kinase assays show that in contrast to palbociclib, abemaciclib directly inhibits (GSK3/β) kinase activity at low nanomolar concentrations. Consequently, abemaciclib activates β-catenin-dependent WNT signaling, as determined by β-catenin transcriptional activation and β-catenin protein stabilization. These data reveal differential kinase target specificities for CDK4/6 inhibitors may help explain differential clinical efficacy and dose-limiting toxicities. More broadly, we highlight the power of competitive chemical proteomics to identify multiple targets of kinase inhibitors in protein lysate, treated cells and in treated mice.
Project description:Anterior tibialis removed from 3-month old muscle glycogen synthase WT or knockout mouse. RNA was extracted using GibcoBRL TRIzol Reagent and a Quiagen RNeasy kit. Targets were produced using standard Affymetrix procedures from about 5ug of total RNA. GSM40057-GSM40063 AND GSM40956. Liver removed from 3-month old muscle glycogen synthase WT or knockout mouse. RNA was extracted using GibcoBRL TRIzol Reagent and a Quiagen RNeasy kit. Targets were produced using standard Affymetrix procedures from about 10ug of total RNA. GSM40064-GSM40071. Medial gastrocnemius removed from 3-month old muscle glycogen synthase WT or knockout mouse. RNA was extracted using GibcoBRL TRIzol Reagent and a Quiagen RNeasy kit. Targets were produced using standard Affymetrix procedures from about 5ug of total RNA. GSM40072-GSM40079. Medial gastrocnemius removed from 8-month old muscle glycogen synthase WT or overexpressing mouse. RNA was extracted using GibcoBRL TRIzol Reagent and a Quiagen RNeasy kit. Targets were produced using standard Affymetrix procedures from about 5ug of total RNA. GSM40080-GSM40089