HMGA1 is a novel downstream nuclear target of the insulin receptor signaling pathway

High-mobility group AT-hook 1 (HMGA1) protein is an important nuclear factor that activates gene transcription by binding to AT-rich sequences in the promoter region of DNA. We previously demonstrated that HMGA1 is a key regulator of the insulin receptor (INSR) gene and individuals with defects in HMGA1 have decreased INSR expression and increased susceptibility to type 2 diabetes mellitus. In addition, there is evidence that intracellular regulatory molecules that are employed by the INSR signaling system are involved in post-translational modifications of HMGA1, including protein phosphorylation. It is known that phosphorylation of HMGA1 reduces DNA-binding affinity and transcriptional activation. In the present study, we investigated whether activation of the INSR by insulin affected HMGA1 protein phosphorylation and its regulation of gene transcription. Collectively, our findings indicate that HMGA1 is a novel downstream target of the INSR signaling pathway, thus representing a new critical nuclear mediator of insulin action and function

Selective Association of Peroxiredoxin 1 with Genomic DNA and COX-2 Upstream Promoter Elements in Estrogen Receptor Negative Breast Cancer Cells

PRDX1 was identified as a protein preferentially crosslinked to DNA in estrogen receptor negative but not in estrogen receptor positive breast cancer cells. In estrogen receptor negative cells, PRDX1 is phosphorylated, binds to NF-κB, and is recruited to COX-2 upstream promoter elements

Mitogen- and Stress-Activated Kinase 1 (MSK1) Regulates Cigarette Smoke-Induced Histone Modifications on NF-κB-dependent Genes

Cigarette smoke (CS) causes sustained lung inflammation, which is an important event in the pathogenesis of chronic obstructive pulmonary disease (COPD). We have previously reported that IKKα (I kappaB kinase alpha) plays a key role in CS-induced pro-inflammatory gene transcription by chromatin modifications; however, the underlying role of downstream signaling kinase is not known. Mitogen- and stress-activated kinase 1 (MSK1) serves as a specific downstream NF-κB RelA/p65 kinase, mediating transcriptional activation of NF-κB-dependent pro-inflammatory genes. The role of MSK1 in nuclear signaling and chromatin modifications is not known, particularly in response to environmental stimuli. We hypothesized that MSK1 regulates chromatin modifications of pro-inflammatory gene promoters in response to CS. Here, we report that CS extract activates MSK1 in human lung epithelial (H292 and BEAS-2B) cell lines, human primary small airway epithelial cells (SAEC), and in mouse lung, resulting in phosphorylation of nuclear MSK1 (Thr581), phospho-acetylation of RelA/p65 at Ser276 and Lys310 respectively. This event was associated with phospho-acetylation of histone H3 (Ser10/Lys9) and acetylation of histone H4 (Lys12). MSK1 N- and C-terminal kinase-dead mutants, MSK1 siRNA-mediated knock-down in transiently transfected H292 cells, and MSK1 stable knock-down mouse embryonic fibroblasts significantly reduced CS extract-induced MSK1, NF-κB RelA/p65 activation, and posttranslational modifications of histones. CS extract/CS promotes the direct interaction of MSK1 with RelA/p65 and p300 in epithelial cells and in mouse lung. Furthermore, CS-mediated recruitment of MSK1 and its substrates to the promoters of NF-κB-dependent pro-inflammatory genes leads to transcriptional activation, as determined by chromatin immunoprecipitation. Thus, MSK1 is an important downstream kinase involved in CS-induced NF-κB activation and chromatin modifications, which have implications in pathogenesis of COPD

Vägledning för erosionsutredning i vattendrag. Förstudie.

Vid släntstabilitetsutredningar exempelvis i samband med framtagande av detaljplan eller väg- och järnvägsplan, bör erosionsförhållandena klarläggas för att säkerställa den långsiktiga släntstabiliteten. Detta är särskilt viktigt då den pågående klimatförändringen kan medföra högre flöden som kan öka påfrestningen på strandkanterna och därmed bidra till ökad stranderosion. Ökad erosion medför en ökad sannolikhet för skred i slänter. Denna förstudie syftar till att ge underlag för en vägledning om hur eros-ionsutredningar kan göras i samband med stabilitetsutredningar. Det är lämpligt att sådana utredningar kan utföras med successivt ökande detaljeringsgrad likt den som gäller för släntstabilitetsutredningar. I dagsläget saknas vägledning för hur en erosionsutredning bör utföras med koppling till släntstabilitet. I samband med SGI:s Göta älvutredning 2009-2012 togs det fram typfall av slänter och erosion som underlag för känslighetsanalys vid beräkning av släntstabiliteten längs Göta Älv. Denna metodik används vid beräkningar i pågående släntstabilitetsutredningar inom Delegationen för Göta Älv. I arbetet med denna förstudie har en litteraturstudie utförts för att kartlägga olika delar inom ämnet stranderosion och om det finns rekommendationer för erosionsutredning. I detta arbete har vi inte påträffat litteratur som ger vägledning för utredning av erosionen med koppling till stabilitetsutredningar eller med successivt ökande detaljeringsgrad. Däremot har vi sammanställt värdefull kunskap som kan användas som en del av en kommande vägledning. Ett förslag har tagits fram som beskriver hur erosionen i ett vattendrag kan utredas i steg med successivt ökande detaljeringsgrad. Detaljeringsgraden anpassas efter vilken fas i samhällsplaneringen som utredning utförs för, t.ex. kommunal översiktsplan, detaljplan eller vägplan. I det fortsatta arbetet med vägledningen avses att redovisa goda exempel på sätt att utreda erosionen och en utökad beskrivning av arbetsgången i utredningsstegen och av de olika metoderna.

Role of MSK1 in the Malignant Phenotype of Ras-transformed Mouse Fibroblasts*

Activated by the RAS-MAPK signaling pathway, MSK1 is recruited to immediate-early gene (IEG) regulatory regions, where it phosphorylates histone H3 at Ser-10 or Ser-28. Chromatin remodelers and modifiers are then recruited by 14-3-3 proteins, readers of phosphoserine marks, leading to the occupancy of IEG promoters by the initiation-engaged form of RNA polymerase II and the onset of transcription. In this study, we show that this mechanism of IEG induction, initially elucidated in parental 10T1/2 murine fibroblast cells, applies to metastatic Hras1-transformed Ciras-3 cells. As the RAS-MAPK pathway is constitutively activated in Ciras-3 cells, MSK1 activity and phosphorylated H3 steady-state levels are elevated. We found that steady-state levels of the IEG products AP-1 and COX-2 were also elevated in Ciras-3 cells. When MSK1 activity was inhibited or MSK1 expression was knocked down in Ciras-3 cells, the induction of IEG expression and the steady-state levels of COX-2, FRA-1, and JUN were greatly reduced. Furthermore, MSK1 knockdown Ciras-3 cells lost their malignant phenotype, as reflected by the absence of anchorage-independent growth

Mitogen- and Stress-Activated Protein Kinases 1 and 2 Are Required for Maximal Trefoil Factor 1 Induction

<div><p>Mitogen- and stress-activated protein kinases 1 and 2 (MSK1 and MSK2), activated downstream of the ERK- and p38-mitogen-activated protein kinase pathways are involved in cell survival, proliferation and differentiation. Following mitogenic or stress stimuli, they mediate the nucleosomal response, which includes phosphorylation of histone H3 at serine 10 (H3S10ph) coupled with transcriptional activation of immediate-early genes. While MSK1 and MSK2 are closely related, their relative roles may vary with cellular context and/or stimuli. However, our knowledge of MSK2 recruitment to immediate-early genes is limited, as research has primarily focused on MSK1. Here, we demonstrate that both MSK1 and MSK2, regulate the phorbol ester 12-O-tetradecanoylphorbol-13-acetate induced expression of the breast cancer marker gene, trefoil factor 1 (<i>TFF1</i>), by phosphorylating H3S10 at its 5′ regulatory regions. The MSK-mediated phosphorylation of H3S10 promotes the recruitment of 14-3-3 isoforms and BRG1, the ATPase subunit of the BAF/PBAF remodeling complex, to the enhancer and upstream promoter elements of <i>TFF1</i>. The recruited chromatin remodeling activity leads to the RNA polymerase II carboxy-terminal domain phosphorylation at the <i>TFF1</i> promoter, initiating <i>TFF1</i> expression in MCF-7 breast cancer cells. Moreover, we show that MSK1 or MSK2 is recruited to <i>TFF1</i> regulatory regions, but as components of different multiprotein complexes.</p></div