1
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Deng X, Yao Q, Horvath A, Jiang Z, Zhao J, Fischer T, Sugiyama T. The fission yeast ortholog of Coilin, Mug174, forms Cajal body-like nuclear condensates and is essential for cellular quiescence. Nucleic Acids Res 2024; 52:9174-9192. [PMID: 38828770 PMCID: PMC11347179 DOI: 10.1093/nar/gkae463] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2023] [Revised: 05/08/2024] [Accepted: 05/16/2024] [Indexed: 06/05/2024] Open
Abstract
The Cajal body, a nuclear condensate, is crucial for ribonucleoprotein assembly, including small nuclear RNPs (snRNPs). While Coilin has been identified as an integral component of Cajal bodies, its exact function remains unclear. Moreover, no Coilin ortholog has been found in unicellular organisms to date. This study unveils Mug174 (Meiosis-upregulated gene 174) as the Coilin ortholog in the fission yeast Schizosaccharomyces pombe. Mug174 forms phase-separated condensates in vitro and is often associated with the nucleolus and the cleavage body in vivo. The generation of Mug174 foci relies on the trimethylguanosine (TMG) synthase Tgs1. Moreover, Mug174 interacts with Tgs1 and U snRNAs. Deletion of the mug174+ gene in S. pombe causes diverse pleiotropic phenotypes, encompassing defects in vegetative growth, meiosis, pre-mRNA splicing, TMG capping of U snRNAs, and chromosome segregation. In addition, we identified weak homology between Mug174 and human Coilin. Notably, human Coilin expressed in fission yeast colocalizes with Mug174. Critically, Mug174 is indispensable for the maintenance of and transition from cellular quiescence. These findings highlight the Coilin ortholog in fission yeast and suggest that the Cajal body is implicated in cellular quiescence, thereby preventing human diseases.
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Affiliation(s)
- Xiaoling Deng
- School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Qinglian Yao
- School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Attila Horvath
- The John Curtin School of Medical Research, The Australian National University, Canberra 2601, Australia
| | - Ziling Jiang
- School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Junjie Zhao
- School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Tamás Fischer
- The John Curtin School of Medical Research, The Australian National University, Canberra 2601, Australia
| | - Tomoyasu Sugiyama
- School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China
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2
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Tsuchiya M, Kong W, Hiraoka Y, Haraguchi T, Ogawa H. TBK1 inhibitors enhance transfection efficiency by suppressing p62/SQSTM1 phosphorylation. Genes Cells 2023; 28:68-77. [PMID: 36284367 DOI: 10.1111/gtc.12987] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2022] [Revised: 10/18/2022] [Accepted: 10/23/2022] [Indexed: 01/19/2023]
Abstract
DNA transfection is an essential technique in the life sciences. Non-viral transfection reagents are widely used for transfection in basic science. However, low transfection efficiency is a problem in some cell types. This low efficiency can be primarily attributed to the intracellular degradation of transfected DNA by p62-dependent selective autophagy, specifically by p62 phosphorylated at the S403 residue (p62-S403-P). To achieve efficient DNA transfection, we focused on a phosphorylation process that generates p62-S403-P and investigated whether inhibition of this process affects transfection efficiency. One of the kinases that phosphorylate p62 is TBK1. The TBK1 gene depletion in murine embryonic fibroblast cells by genome editing caused a significant reduction or loss of p62-S405-P (equivalent to human S403-P) and enhanced transfection efficiency, suggesting that TBK1 is a major kinase that phosphorylates p62 at S403. Therefore, TBK1 is a viable target for drug treatment to increase transfection efficiency. Transfection efficiency was enhanced when cells were treated with one of the following TBK1 inhibitors BX795, MRT67307, or amlexanox. This effect was synergistically improved when the two inhibitors were used in combination. Our results indicate that TBK1 inhibitors enhanced transfection efficiency by suppressing p62 phosphorylation.
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Affiliation(s)
- Megumi Tsuchiya
- Graduate School of Frontier Biosciences, Osaka University, Suita, Japan
| | - Weixia Kong
- Graduate School of Frontier Biosciences, Osaka University, Suita, Japan
| | - Yasushi Hiraoka
- Graduate School of Frontier Biosciences, Osaka University, Suita, Japan
| | - Tokuko Haraguchi
- Graduate School of Frontier Biosciences, Osaka University, Suita, Japan
| | - Hidesato Ogawa
- Graduate School of Frontier Biosciences, Osaka University, Suita, Japan
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3
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Pinheiro EDS, Preato AM, Petrucci TVB, dos Santos LS, Glezer I. Phase-separation: a possible new layer for transcriptional regulation by glucocorticoid receptor. Front Endocrinol (Lausanne) 2023; 14:1160238. [PMID: 37124728 PMCID: PMC10145926 DOI: 10.3389/fendo.2023.1160238] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/06/2023] [Accepted: 03/20/2023] [Indexed: 05/02/2023] Open
Abstract
Glucocorticoids (GCs) are hormones involved in circadian adaptation and stress response, and it is also noteworthy that these steroidal molecules present potent anti-inflammatory action through GC receptors (GR). Upon ligand-mediated activation, GR translocates to the nucleus, and regulates gene expression related to metabolism, acute-phase response and innate immune response. GR field of research has evolved considerably in the last decades, providing varied mechanisms that contributed to the understanding of transcriptional regulation and also impacted drug design for treating inflammatory diseases. Liquid-liquid phase separation (LLPS) in cellular processes represents a recent topic in biology that conceptualizes membraneless organelles and microenvironments that promote, or inhibit, chemical reactions and interactions of protein or nucleic acids. The formation of these molecular condensates has been implicated in gene expression control, and recent evidence shows that GR and other steroid receptors can nucleate phase separation (PS). Here we briefly review the varied mechanisms of transcriptional control by GR, which are largely studied in the context of inflammation, and further present how PS can be involved in the control of gene expression. Lastly, we consider how the reported advances on LLPS during transcription control, specially for steroid hormone receptors, could impact the different modalities of GR action on gene expression, adding a new plausible molecular event in glucocorticoid signal transduction.
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4
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Tsuchiya M, Ogawa H, Watanabe K, Koujin T, Mori C, Nunomura K, Lin B, Tani A, Hiraoka Y, Haraguchi T. Microtubule inhibitors identified through nonbiased screening enhance DNA transfection efficiency by delaying p62-dependent ubiquitin recruitment. Genes Cells 2021; 26:739-751. [PMID: 34212463 DOI: 10.1111/gtc.12881] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2021] [Revised: 06/26/2021] [Accepted: 06/30/2021] [Indexed: 11/26/2022]
Abstract
Ectopic gene expression is an indispensable tool in biology and medicine, but is often limited by the low efficiency of DNA transfection. We previously reported that depletion of the autophagy receptor p62/SQSTM1 enhances DNA transfection efficiency by preventing the degradation of transfected DNA. Therefore, p62 is a potential target for drugs to increase transfection efficiency. To identify such drugs, a nonbiased high-throughput screening was applied to over 4,000 compounds from the Osaka University compound library, and their p62 dependency was evaluated. The top-scoring drugs were mostly microtubule inhibitors, such as colchicine and vinblastine, and all of them showed positive effects only in the presence of p62. To understand the p62-dependent mechanisms, the time required for p62-dependent ubiquitination, which is required for autophagosome formation, was examined using polystyrene beads that were introduced into cells as materials that mimicked transfected DNA. Microtubule inhibitors caused a delay in ubiquitination. Furthermore, the level of phosphorylated p62 at S405 was markedly decreased in the drug-treated cells. These results suggest that microtubule inhibitors inhibit p62-dependent autophagosome formation. Our findings demonstrate for the first time that microtubule inhibitors suppress p62 activation as a mechanism for increasing DNA transfection efficiency and provide solutions to increase efficiency.
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Affiliation(s)
- Megumi Tsuchiya
- Graduate School of Frontier Biosciences, Osaka University, Suita, Japan
| | - Hidesato Ogawa
- Graduate School of Frontier Biosciences, Osaka University, Suita, Japan
| | - Kento Watanabe
- Graduate School of Frontier Biosciences, Osaka University, Suita, Japan
| | - Takako Koujin
- Advanced ICT Research Institute Kobe, National Institute of Information and Communications Technology, Kobe, Japan
| | - Chie Mori
- Advanced ICT Research Institute Kobe, National Institute of Information and Communications Technology, Kobe, Japan
| | - Kazuto Nunomura
- Graduate School of Pharmaceutical Science, Osaka University, Suita, Japan
| | - Bangzhong Lin
- Graduate School of Pharmaceutical Science, Osaka University, Suita, Japan
| | - Akiyoshi Tani
- Graduate School of Pharmaceutical Science, Osaka University, Suita, Japan
| | - Yasushi Hiraoka
- Graduate School of Frontier Biosciences, Osaka University, Suita, Japan.,Advanced ICT Research Institute Kobe, National Institute of Information and Communications Technology, Kobe, Japan
| | - Tokuko Haraguchi
- Graduate School of Frontier Biosciences, Osaka University, Suita, Japan.,Advanced ICT Research Institute Kobe, National Institute of Information and Communications Technology, Kobe, Japan
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5
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Naiman S, Huynh FK, Gil R, Glick Y, Shahar Y, Touitou N, Nahum L, Avivi MY, Roichman A, Kanfi Y, Gertler AA, Doniger T, Ilkayeva OR, Abramovich I, Yaron O, Lerrer B, Gottlieb E, Harris RA, Gerber D, Hirschey MD, Cohen HY. SIRT6 Promotes Hepatic Beta-Oxidation via Activation of PPARα. Cell Rep 2019; 29:4127-4143.e8. [PMID: 31851938 PMCID: PMC7165364 DOI: 10.1016/j.celrep.2019.11.067] [Citation(s) in RCA: 61] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2019] [Revised: 10/11/2019] [Accepted: 11/15/2019] [Indexed: 12/27/2022] Open
Abstract
The pro-longevity enzyme SIRT6 regulates various metabolic pathways. Gene expression analyses in SIRT6 heterozygotic mice identify significant decreases in PPARα signaling, known to regulate multiple metabolic pathways. SIRT6 binds PPARα and its response element within promoter regions and activates gene transcription. Sirt6+/- results in significantly reduced PPARα-induced β-oxidation and its metabolites and reduced alanine and lactate levels, while inducing pyruvate oxidation. Reciprocally, starved SIRT6 transgenic mice show increased pyruvate, acetylcarnitine, and glycerol levels and significantly induce β-oxidation genes in a PPARα-dependent manner. Furthermore, SIRT6 mediates PPARα inhibition of SREBP-dependent cholesterol and triglyceride synthesis. Mechanistically, SIRT6 binds PPARα coactivator NCOA2 and decreases liver NCOA2 K780 acetylation, which stimulates its activation of PPARα in a SIRT6-dependent manner. These coordinated SIRT6 activities lead to regulation of whole-body respiratory exchange ratio and liver fat content, revealing the interactions whereby SIRT6 synchronizes various metabolic pathways, and suggest a mechanism by which SIRT6 maintains healthy liver.
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Affiliation(s)
- Shoshana Naiman
- Mina and Everard Goodman Faculty of Life Sciences, Bar Ilan University, Ramat Gan 5290002, Israel
| | - Frank K Huynh
- Department of Biological Sciences, San Jose State University, San Jose, CA 95192, USA; Sarah W. Stedman Nutrition and Metabolism Center, Duke Molecular Physiology Institute, Duke University Medical Center, Durham, NC 27710, USA; Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, NC 27710, USA; Department of Medicine, Division of Endocrinology, Metabolism, and Nutrition, Duke University Medical Center, Durham, NC 27710, USA
| | - Reuven Gil
- Mina and Everard Goodman Faculty of Life Sciences, Bar Ilan University, Ramat Gan 5290002, Israel
| | - Yair Glick
- Mina and Everard Goodman Faculty of Life Sciences, Bar Ilan University, Ramat Gan 5290002, Israel
| | - Yael Shahar
- Mina and Everard Goodman Faculty of Life Sciences, Bar Ilan University, Ramat Gan 5290002, Israel
| | - Noga Touitou
- Mina and Everard Goodman Faculty of Life Sciences, Bar Ilan University, Ramat Gan 5290002, Israel
| | - Liat Nahum
- Mina and Everard Goodman Faculty of Life Sciences, Bar Ilan University, Ramat Gan 5290002, Israel
| | - Matan Y Avivi
- Mina and Everard Goodman Faculty of Life Sciences, Bar Ilan University, Ramat Gan 5290002, Israel
| | - Asael Roichman
- Mina and Everard Goodman Faculty of Life Sciences, Bar Ilan University, Ramat Gan 5290002, Israel
| | - Yariv Kanfi
- Mina and Everard Goodman Faculty of Life Sciences, Bar Ilan University, Ramat Gan 5290002, Israel
| | - Asaf A Gertler
- Mina and Everard Goodman Faculty of Life Sciences, Bar Ilan University, Ramat Gan 5290002, Israel
| | - Tirza Doniger
- Mina and Everard Goodman Faculty of Life Sciences, Bar Ilan University, Ramat Gan 5290002, Israel
| | - Olga R Ilkayeva
- Sarah W. Stedman Nutrition and Metabolism Center, Duke Molecular Physiology Institute, Duke University Medical Center, Durham, NC 27710, USA; Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, NC 27710, USA; Department of Medicine, Division of Endocrinology, Metabolism, and Nutrition, Duke University Medical Center, Durham, NC 27710, USA
| | - Ifat Abramovich
- The Ruth and Bruce Rappaport Faculty of Medicine, Technion-Israel Institute of Technology, 1 Efron Street, Bat Galim, Haifa, Israel
| | - Orly Yaron
- Mina and Everard Goodman Faculty of Life Sciences, Bar Ilan University, Ramat Gan 5290002, Israel
| | - Batia Lerrer
- Mina and Everard Goodman Faculty of Life Sciences, Bar Ilan University, Ramat Gan 5290002, Israel
| | - Eyal Gottlieb
- The Ruth and Bruce Rappaport Faculty of Medicine, Technion-Israel Institute of Technology, 1 Efron Street, Bat Galim, Haifa, Israel
| | - Robert A Harris
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Doron Gerber
- Mina and Everard Goodman Faculty of Life Sciences, Bar Ilan University, Ramat Gan 5290002, Israel; Bar Ilan Institute for Nanotechnology and Advanced Materials, Bar Ilan University, Ramat Gan 5290002, Israel
| | - Matthew D Hirschey
- Sarah W. Stedman Nutrition and Metabolism Center, Duke Molecular Physiology Institute, Duke University Medical Center, Durham, NC 27710, USA; Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, NC 27710, USA; Department of Medicine, Division of Endocrinology, Metabolism, and Nutrition, Duke University Medical Center, Durham, NC 27710, USA
| | - Haim Y Cohen
- Mina and Everard Goodman Faculty of Life Sciences, Bar Ilan University, Ramat Gan 5290002, Israel.
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6
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Bartlett AA, Lapp HE, Hunter RG. Epigenetic Mechanisms of the Glucocorticoid Receptor. Trends Endocrinol Metab 2019; 30:807-818. [PMID: 31699238 DOI: 10.1016/j.tem.2019.07.003] [Citation(s) in RCA: 48] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/05/2019] [Revised: 06/17/2019] [Accepted: 07/08/2019] [Indexed: 02/07/2023]
Abstract
The glucocorticoid receptor (GR) has been shown to be important for mediating cellular responses to stress and circulating glucocorticoids. Ligand-dependent transcriptional changes induced by GR are observed across numerous tissues. However, the mechanisms by which GR achieves cell and tissue-specific effects are less clear. Epigenetic mechanisms have been proposed to explain some of these differences as well as some of the lasting, even transgenerational, effects of stress and glucocorticoid action. GR functions in tandem with epigenetic cellular machinery to coordinate transcription and shape chromatin structure. Here, we describe GR interactions with these effectors and how GR acts to reshape the epigenetic landscape in response to the environment.
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Affiliation(s)
- Andrew A Bartlett
- Department of Psychology, University of Massachusetts Boston, 100 Morrissey Blvd, Boston, MA 02125, USA
| | - Hannah E Lapp
- Department of Psychology, University of Massachusetts Boston, 100 Morrissey Blvd, Boston, MA 02125, USA
| | - Richard G Hunter
- Department of Psychology, University of Massachusetts Boston, 100 Morrissey Blvd, Boston, MA 02125, USA.
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7
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Mapping the Dynamics of the Glucocorticoid Receptor within the Nuclear Landscape. Sci Rep 2017; 7:6219. [PMID: 28740156 PMCID: PMC5524710 DOI: 10.1038/s41598-017-06676-0] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2017] [Accepted: 06/15/2017] [Indexed: 12/28/2022] Open
Abstract
The distribution of the transcription machinery among different sub-nuclear domains raises the question on how the architecture of the nucleus modulates the transcriptional response. Here, we used fluorescence fluctuation analyses to quantitatively explore the organization of the glucocorticoid receptor (GR) in the interphase nucleus of living cells. We found that this ligand-activated transcription factor diffuses within the nucleus and dynamically interacts with bodies enriched in the coregulator NCoA-2, DNA-dependent foci and chromatin targets. The distribution of the receptor among the nuclear compartments depends on NCoA-2 and the conformation of the receptor as assessed with synthetic ligands and GR mutants with impaired transcriptional abilities. Our results suggest that the partition of the receptor in different nuclear reservoirs ultimately regulates the concentration of receptor available for the interaction with specific targets, and thus has an impact on transcription regulation.
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8
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Weikum ER, Knuesel MT, Ortlund EA, Yamamoto KR. Glucocorticoid receptor control of transcription: precision and plasticity via allostery. Nat Rev Mol Cell Biol 2017; 18:159-174. [PMID: 28053348 PMCID: PMC6257982 DOI: 10.1038/nrm.2016.152] [Citation(s) in RCA: 356] [Impact Index Per Article: 44.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The glucocorticoid receptor (GR) is a constitutively expressed transcriptional regulatory factor (TRF) that controls many distinct gene networks, each uniquely determined by particular cellular and physiological contexts. The precision of GR-mediated responses seems to depend on combinatorial, context-specific assembly of GR-nucleated transcription regulatory complexes at genomic response elements. In turn, evidence suggests that context-driven plasticity is conferred by the integration of multiple signals, each serving as an allosteric effector of GR conformation, a key determinant of regulatory complex composition and activity. This structural and mechanistic perspective on GR regulatory specificity is likely to extend to other eukaryotic TRFs.
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Affiliation(s)
- Emily R Weikum
- Department of Biochemistry, Emory University School of Medicine, 1510 Clifton Road, Atlanta, Georgia 30322, USA
| | - Matthew T Knuesel
- Department of Cellular and Molecular Pharmacology, University of California San Francisco School of Medicine, 600 16th Street, San Francisco, California 94143, USA
| | - Eric A Ortlund
- Department of Biochemistry, Emory University School of Medicine, 1510 Clifton Road, Atlanta, Georgia 30322, USA
| | - Keith R Yamamoto
- Department of Cellular and Molecular Pharmacology, University of California San Francisco School of Medicine, 600 16th Street, San Francisco, California 94143, USA
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9
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Tsuchiya M, Ogawa H, Koujin T, Kobayashi S, Mori C, Hiraoka Y, Haraguchi T. Depletion of autophagy receptor p62/SQSTM1 enhances the efficiency of gene delivery in mammalian cells. FEBS Lett 2016; 590:2671-80. [PMID: 27317902 DOI: 10.1002/1873-3468.12262] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2016] [Revised: 05/26/2016] [Accepted: 06/14/2016] [Indexed: 12/29/2022]
Abstract
Novel methods that increase the efficiency of gene delivery to cells will have many useful applications. Here, we report a simple approach involving depletion of p62/SQSTM1 to enhance the efficiency of gene delivery. The efficiency of reporter gene delivery was remarkably higher in p62-knockout murine embryonic fibroblast (MEF) cells compared with normal MEF cells. This higher efficiency was partially attenuated by ectopic expression of p62. Furthermore, siRNA-mediated knockdown of p62 clearly increased the efficiency of transfection of murine embryonic stem (mES) cells and human HeLa cells. These data indicate that p62 acts as a key regulator of gene delivery.
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Affiliation(s)
- Megumi Tsuchiya
- Graduate School of Frontier Biosciences, Osaka University, Suita, Japan
| | - Hidesato Ogawa
- Graduate School of Frontier Biosciences, Osaka University, Suita, Japan.,Advanced ICT Research Institute Kobe, National Institute of Information and Communications Technology, Kobe, Japan
| | - Takako Koujin
- Advanced ICT Research Institute Kobe, National Institute of Information and Communications Technology, Kobe, Japan
| | - Shouhei Kobayashi
- Advanced ICT Research Institute Kobe, National Institute of Information and Communications Technology, Kobe, Japan
| | - Chie Mori
- Advanced ICT Research Institute Kobe, National Institute of Information and Communications Technology, Kobe, Japan
| | - Yasushi Hiraoka
- Graduate School of Frontier Biosciences, Osaka University, Suita, Japan.,Advanced ICT Research Institute Kobe, National Institute of Information and Communications Technology, Kobe, Japan
| | - Tokuko Haraguchi
- Graduate School of Frontier Biosciences, Osaka University, Suita, Japan.,Advanced ICT Research Institute Kobe, National Institute of Information and Communications Technology, Kobe, Japan
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10
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Sugiyama T, Wanatabe N, Kitahata E, Tani T, Sugioka-Sugiyama R. Red5 and three nuclear pore components are essential for efficient suppression of specific mRNAs during vegetative growth of fission yeast. Nucleic Acids Res 2013; 41:6674-86. [PMID: 23658229 PMCID: PMC3711435 DOI: 10.1093/nar/gkt363] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Zinc-finger domains are found in many nucleic acid-binding proteins in both prokaryotes and eukaryotes. Proteins carrying zinc-finger domains have important roles in various nuclear transactions, including transcription, mRNA processing and mRNA export; however, for many individual zinc-finger proteins in eukaryotes, the exact function of the protein is not fully understood. Here, we report that Red5 is involved in efficient suppression of specific mRNAs during vegetative growth of Schizosaccharomyces pombe. Red5, which contains five C3H1-type zinc-finger domains, localizes to the nucleus where it forms discrete dots. A red5 point mutation, red5-2, results in the upregulation of specific meiotic mRNAs in vegetative mutant red5-2 cells; northern blot data indicated that these meiotic mRNAs in red5-2 cells have elongated poly(A) tails. RNA-fluorescence in situ hybridization results demonstrate that poly(A)+ RNA species accumulate in the nucleolar regions of red5-deficient cells. Moreover, Red5 genetically interacts with several mRNA export factors. Unexpectedly, three components of the nuclear pore complex also suppress a specific set of meiotic mRNAs. These results indicate that Red5 function is important to meiotic mRNA degradation; they also suggest possible connections among selective mRNA decay, mRNA export and the nuclear pore complex in vegetative fission yeast.
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11
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Sugiyama T, Sugioka-Sugiyama R, Hada K, Niwa R. Rhn1, a nuclear protein, is required for suppression of meiotic mRNAs in mitotically dividing fission yeast. PLoS One 2012; 7:e42962. [PMID: 22912768 PMCID: PMC3422304 DOI: 10.1371/journal.pone.0042962] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2012] [Accepted: 07/16/2012] [Indexed: 12/23/2022] Open
Abstract
In the fission yeast Schizosaccharomyces pombe, many meiotic mRNAs are transcribed during mitosis and meiosis and selectively eliminated in mitotic cells. However, this pathway for mRNA decay, called the determinant of selective removal (DSR)-Mmi1 system, targets only some of the numerous meiotic mRNAs that are transcribed in mitotic cells. Here we describe Rhn1, a nuclear protein involved in meiotic mRNA suppression in vegetative fission yeast. Rhn1 is homologous to budding yeast Rtt103 and localizes to one or a few discrete nuclear dots in growing vegetative cells. Rhn1 colocalizes with a pre-mRNA 3′-end processing factor, Pcf11, and with the 5′–3′ exoribonuclease, Dhp1; moreover, Rhn1 coimmunoprecipitates with Pcf11. Loss of rhn1 results in elevated sensitivity to high temperature, to thiabendazole (TBZ), and to UV. Interestingly, meiotic mRNAs—including moa1+, mcp5+, and mug96+—accumulate in mitotic rhn1Δ cells. Accumulation of meiotic mRNAs also occurs in strains lacking Lsk1, a kinase that phosphorylates serine 2 (Ser-2) in the C-terminal domain (CTD) of RNA polymerase II (Pol II), and in strains lacking Sen1, an ATP-dependent 5′–3′ RNA/DNA helicase: notably, both Lsk1 and Sen1 have been implicated in termination of Pol II-dependent transcription. Furthermore, RNAi knockdown of cids-2, a Caenorhabditis elegans ortholog of rhn1+, leads to elevated expression of a germline-specific gene, pgl-1, in somatic cells. These results indicate that Rhn1 contributes to the suppression of meiotic mRNAs in vegetative fission yeast and that the mechanism by which Rhn1 downregulates germline-specific transcripts may be conserved in unicellular and multicellular organisms.
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Affiliation(s)
- Tomoyasu Sugiyama
- Graduate School of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Ibaraki, Japan.
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12
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Red1 promotes the elimination of meiosis-specific mRNAs in vegetatively growing fission yeast. EMBO J 2011; 30:1027-39. [PMID: 21317872 DOI: 10.1038/emboj.2011.32] [Citation(s) in RCA: 77] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2010] [Accepted: 01/21/2011] [Indexed: 01/01/2023] Open
Abstract
Meiosis-specific mRNAs are transcribed in vegetative fission yeast, and these meiotic mRNAs are selectively removed from mitotic cells to suppress meiosis. This RNA elimination system requires degradation signal sequences called determinant of selective removal (DSR), an RNA-binding protein Mmi1, polyadenylation factors, and the nuclear exosome. However, the detailed mechanism by which meiotic mRNAs are selectively degraded in mitosis but not meiosis is not understood fully. Here we report that Red1, a novel protein, is essential for elimination of meiotic mRNAs from mitotic cells. A red1 deletion results in the accumulation of a large number of meiotic mRNAs in mitotic cells. Red1 interacts with Mmi1, Pla1, the canonical poly(A) polymerase, and Rrp6, a subunit of the nuclear exosome, and promotes the destabilization of DSR-containing mRNAs. Moreover, Red1 forms nuclear bodies in mitotic cells, and these foci are disassembled during meiosis. These results demonstrate that Red1 is involved in DSR-directed RNA decay to prevent ectopic expression of meiotic mRNAs in vegetative cells.
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13
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Presman DM, Alvarez LD, Levi V, Eduardo S, Digman MA, Martí MA, Veleiro AS, Burton G, Pecci A. Insights on glucocorticoid receptor activity modulation through the binding of rigid steroids. PLoS One 2010; 5:e13279. [PMID: 20949009 PMCID: PMC2952596 DOI: 10.1371/journal.pone.0013279] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2010] [Accepted: 09/16/2010] [Indexed: 02/02/2023] Open
Abstract
BACKGROUND The glucocorticoid receptor (GR) is a transcription factor that regulates gene expression in a ligand-dependent fashion. This modular protein is one of the major pharmacological targets due to its involvement in both cause and treatment of many human diseases. Intense efforts have been made to get information about the molecular basis of GR activity. METHODOLOGY/PRINCIPAL FINDINGS Here, the behavior of four GR-ligand complexes with different glucocorticoid and antiglucocorticoid properties were evaluated. The ability of GR-ligand complexes to oligomerize in vivo was analyzed by performing the novel Number and Brightness assay. Results showed that most of GR molecules form homodimers inside the nucleus upon ligand binding. Additionally, in vitro GR-DNA binding analyses suggest that ligand structure modulates GR-DNA interaction dynamics rather than the receptor's ability to bind DNA. On the other hand, by coimmunoprecipitation studies we evaluated the in vivo interaction between the transcriptional intermediary factor 2 (TIF2) coactivator and different GR-ligand complexes. No correlation was found between GR intranuclear distribution, cofactor recruitment and the homodimerization process. Finally, Molecular determinants that support the observed experimental GR LBD-ligand/TIF2 interaction were found by Molecular Dynamics simulation. CONCLUSIONS/SIGNIFICANCE The data presented here sustain the idea that in vivo GR homodimerization inside the nucleus can be achieved in a DNA-independent fashion, without ruling out a dependent pathway as well. Moreover, since at least one GR-ligand complex is able to induce homodimer formation while preventing TIF2 coactivator interaction, results suggest that these two events might be independent from each other. Finally, 21-hydroxy-6,19-epoxyprogesterone arises as a selective glucocorticoid with potential pharmacological interest. Taking into account that GR homodimerization and cofactor recruitment are considered essential steps in the receptor activation pathway, results presented here contribute to understand how specific ligands influence GR behavior.
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Affiliation(s)
- Diego M. Presman
- Departamento de Química Biológica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, Argentina
- IFIBYNE-CONICET, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Lautaro D. Alvarez
- Departamento de Química Orgánica/UMYMFOR-CONICET, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Valeria Levi
- Departamento de Química Biológica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Silvina Eduardo
- Departamento de Química Orgánica/UMYMFOR-CONICET, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Michelle A. Digman
- Laboratory for Fluorescence Dynamics, Department of Biomedical Engineering and Developmental Biology Center Optical Biology Core Facility, University of California Irvine, Irvine, California, United States of America
| | - Marcelo A. Martí
- Departamento de Química Biológica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, Argentina
- INQUIMAE-CONICET, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Adriana S. Veleiro
- Departamento de Química Orgánica/UMYMFOR-CONICET, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Gerardo Burton
- Departamento de Química Orgánica/UMYMFOR-CONICET, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Adali Pecci
- Departamento de Química Biológica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, Argentina
- IFIBYNE-CONICET, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, Argentina
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14
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Pondugula SR, Brimer-Cline C, Wu J, Schuetz EG, Tyagi RK, Chen T. A phosphomimetic mutation at threonine-57 abolishes transactivation activity and alters nuclear localization pattern of human pregnane x receptor. Drug Metab Dispos 2009; 37:719-30. [PMID: 19171678 DOI: 10.1124/dmd.108.024695] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
The pregnane X receptor (PXR) plays crucial roles in multiple physiological processes. However, the signaling mechanisms responsible are not well defined; it is most likely that multiple functions of PXR are modulated by its phosphorylation. Therefore, we sought to determine whether mutation at a highly conserved Thr(57) affects human PXR (hPXR) function. Site-directed mutagenesis was performed to generate phosphorylation-deficient (hPXR(T57A)) and phosphomimetic (hPXR(T57D)) mutants. Gene reporter, Western blotting, immunocytochemistry, mammalian two-hybrid, and electrophoretic mobility shift assays were used to study cytochrome P450 3A4 (CYP3A4) promoter activation, protein levels, localization, cofactor interaction, and CYP3A4 promoter binding of the hPXR mutants, respectively. hPXR(T57D), but not hPXR(T57A), lost its transcriptional activity. Neither mutation altered hPXR's protein levels and interaction with steroid receptor coactivator-1. hPXR and hPXR(T57A) exhibited a homogenous nuclear distribution, whereas hPXR(T57D) exhibited a distinctive punctate nuclear localization pattern similar to that of hPXR mutants with impaired function that colocalize with silencing mediator of retinoid and thyroid receptors (SMRT), although silencing of SMRT did not rescue the altered function of hPXR(T57D). However, hPXR(T57D), but not hPXR(T57A), impaired hPXR's ability to bind to the CYP3A4 promoter, consistent with the mutant's transactivation function. Furthermore, the 70-kDa form of ribosomal protein S6 kinase (p70 S6K) phosphorylated hPXR in vitro and inhibited its transcriptional activity, whereas hPXR(T57A) partially resisted the inhibitory effect of p70 S6K. Our studies identify a functionally significant phosphomimetic mutant (hPXR(T57D)) and show p70 S6K phosphorylation and regulation of hPXR transactivation to support the notion that phosphorylation plays important roles in regulating hPXR function.
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Affiliation(s)
- Satyanarayana R Pondugula
- Department of Chemical Biology and Therapeutics, St. Jude Children's Research Hospital, 262 Danny Thomas Place, Mail Stop 1000, Memphis, TN 38105, USA
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15
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Faria CDC, Longui CA. [Molecular aspects of glucocorticoid sensitivity]. ACTA ACUST UNITED AC 2008; 50:983-95. [PMID: 17221103 DOI: 10.1590/s0004-27302006000600003] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2005] [Accepted: 05/29/2006] [Indexed: 11/22/2022]
Abstract
Glucocorticoids play an essential role in maintaining basal and stress-related homeostasis. Most known effects of glucocorticoids are mediated by the intracellular glucocorticoid receptors. The glucocorticoid sensitivity seems to depend on the amount of receptors expressed and the efficiency of glucocorticoid receptor-mediated signal transduction. Glucocorticoid resistance or hypersensitivity, seen in autoimmune-inflammatory diseases and in metabolic syndrome respectively, can represent the variability of several steps that influence the signaling cascade of glucocorticoid action. The recognition of these steps could provide the understanding of the clinical phenotype and course of such diseases as well as their responsiveness to glucocorticoid therapy. The comprehension of these pathophysiological mechanisms can also improve the possible therapeutic interventions. In this review, we have summarized the multiple factors that have been shown to be involved in this signaling cascade and, thus, to influence glucocorticoid sensitivity.
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Affiliation(s)
- Cláudia D C Faria
- Laboratório de Medicina Molecular, Departamento de Ciências Fisiológicas, Faculdade de Ciências Médicas, Santa Casa de São Paulo, SP.
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16
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Chen W, Roeder RG. The Mediator subunit MED1/TRAP220 is required for optimal glucocorticoid receptor-mediated transcription activation. Nucleic Acids Res 2007; 35:6161-9. [PMID: 17827210 PMCID: PMC2094069 DOI: 10.1093/nar/gkm661] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The MED1/TRAP220 subunit of the Mediator plays a key role in facilitating ligand-dependent interactions of this multisubunit coactivator complex with nuclear receptors through their ligand binding domains. The isolated MED1/TRAP220 protein previously was shown to interact with glucocorticoid receptor (GR) in a ligand-dependent manner. However, the functional role of MED1/TRAP220, within the context of the entire Mediator, is not well studied in GR-mediated transcription. In this study, we show that GR binds directly to the Mediator complex and that both LXXLL motifs of MED1/TRAP220 contribute to its binding to GR. Furthermore, using a Med1/Trap220-/- mouse embryonic fibroblast (MEF) line that lacks entirely MED1/TRAP220, we show that MED1/TRAP220 enhances GR-mediated transcription from an MMTV promoter based-reporter gene and that mutations in the MED1/TRAP220 LXXLL motifs reduce, but do not eliminate, GR-dependent transcription. An analysis of endogenous genes in Med1/Trap220-/- cells has confirmed a variable MED1/TRAP220 requirement for different GR target genes. Taken together, these findings support the idea that Mediator, at least in part through MED1/TRAP220, plays a coregulatory role in ligand-dependent GR-mediated gene expression.
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Affiliation(s)
| | - Robert G. Roeder
- *To whom correspondence should be addressed. +1 212 327 7600+1 212 327 7949
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17
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Gupta P, Park SW, Farooqui M, Wei LN. Orphan nuclear receptor TR2, a mediator of preadipocyte proliferation, is differentially regulated by RA through exchange of coactivator PCAF with corepressor RIP140 on a platform molecule GRIP1. Nucleic Acids Res 2007; 35:2269-82. [PMID: 17389641 PMCID: PMC1874640 DOI: 10.1093/nar/gkl1147] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2006] [Revised: 11/12/2006] [Accepted: 12/15/2006] [Indexed: 01/15/2023] Open
Abstract
Orphan nuclear receptor TR2 is a preadipocyte proliferator. Knockdown of TR2 in 3T3-L1 preadipocytes reduced their proliferation efficiency, whereas specific elevation of TR2 in these cells facilitated their proliferation. All-trans retinoic acid (RA) stimulates cellular proliferation in 3T3-L1 preadipocytes by activating TR2 through an IR0-type RA response element, which further activates c-Myc expression. In post-differentiated adipocytes, RA becomes a repressive signal for TR2 and rapidly down-regulates its expression. The biphasic effect of RA on TR2 expression in 3T3-L1 is mediated by differential RA-dependent coregulator recruitment to the receptor/Glucocorticoid Receptor-Interacting Protein 1 (GRIP1) complex that binds IR0 on the TR2 promoter. RA induces the recruitment of histone acetyl transferase-containing/GRIP1/p300/CBP-associated factor (PCAF) complex to the TR2 promoter in undifferentiated cells, whereas it triggers recruitment of histone deacetylase-containing/GRIP1/receptor-interacting protein 140 (RIP140) complex in differentiated cells. GRIP1 directly interacts with RIP140 through its carboxyl terminal AD2 domain. GRIP1 interacts with PCAF and RIP140 directly and differentially, functioning as a platform molecule to mediate differential RA-induced coregulator recruitment to TR2 promoter target. This results in a biphasic effect of RA on the expression of TR2 in undifferentiated and differentiated cells, which is required for RA-stimulated preadipocyte proliferation.
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Affiliation(s)
| | | | | | - L.-N. Wei
- Department of Pharmacology, University of Minnesota Medical School, Minneapolis, MN 55455, USA
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18
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Grenier J, Trousson A, Chauchereau A, Cartaud J, Schumacher M, Massaad C. Differential recruitment of p160 coactivators by glucocorticoid receptor between Schwann cells and astrocytes. Mol Endocrinol 2005; 20:254-67. [PMID: 16179382 DOI: 10.1210/me.2005-0061] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
In the nervous system, glucocorticoids can exert beneficial or noxious effects, depending on their concentration and the duration of hormonal stimulation. They exert their effects on neuronal and glial cells by means of their cognate receptor, the glucocorticoid receptor (GR), which recruits the p160 coactivator family members SRC-1 (steroid receptor coactivator 1), SRC-2, and SRC-3 after hormone binding. In this study, we investigated the molecular pathways used by the GR in cultured glial cells of the central and the peripheral nervous systems, astrocytes and Schwann cells (MSC80 cells), respectively. We performed functional studies based on transient transfection of a minimal glucocorticoid-sensitive reporter gene into the glial cells to test the influence of overexpression or selective inhibition by short interfering RNA of the three p160 coactivator family members on GR transactivation. We demonstrate that, depending on the glial cell type, GR differentially recruits p160 family members: in Schwann cells, GR recruited SRC-1a, SRC-1e, or SRC-3, whereas in astrocytes, SRC-1e and SRC-2, and to a lesser extent SRC-3, were active toward GR signaling. The C-terminal nuclear receptor-interacting domain of SRC-1a participates in its exclusion from the GR transcriptional complex in astrocytes. Immunolocalization experiments revealed a cell-specific intracellular distribution of the p160s, which was dependent on the duration of the hormonal induction. For example, within astrocytes, SRC-1 and SRC-2 were mainly nuclear, whereas SRC-3 unexpectedly localized to the lumen of the Golgi apparatus. In contrast, in Schwann cells, SRC-1 showed a nucleocytoplasmic shuttling depending on hormonal stimulation, whereas SRC-2 remained strictly nuclear and SRC-3 remained predominantly cytoplasmic. Altogether, these results highlight the cell specificity and the time dependence of p160s recruitment by the activated GR in glial cells, revealing the complexity of GR-p160 assembly in the nervous system.
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Affiliation(s)
- Julien Grenier
- Institut National de la Santé et de la Recherche Médicale Unité Mixte de Recherche 488, 80 rue du Général Leclerc, 94276 Le Kremlin-Bicêtre Cedex, France
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19
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Hoang T, Fenne IS, Cook C, Børud B, Bakke M, Lien EA, Mellgren G. cAMP-dependent protein kinase regulates ubiquitin-proteasome-mediated degradation and subcellular localization of the nuclear receptor coactivator GRIP1. J Biol Chem 2004; 279:49120-30. [PMID: 15347661 DOI: 10.1074/jbc.m409746200] [Citation(s) in RCA: 60] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Nuclear receptors and their coactivators are key regulators of numerous physiological functions. GRIP1 (glucocorticoid receptor-interacting protein) is a member of the steroid receptor coactivator family. Here, we show that GRIP1 is regulated by cAMP-dependent protein kinase (PKA) that induces its degradation through the ubiquitin-proteasome pathway. GRIP1 was down-regulated in transiently transfected COS-1 cells after treatment with 8-para-chlorophenylthio-cAMP or forskolin and 3-isobutyl-1-methylxanthine and in adrenocortical Y1 cells after incubation with adrenocorticotropic hormone. Pulse-chase experiments with transiently transfected COS-1 cells demonstrated that the half-life of GRIP1 was markedly reduced in cells overexpressing the PKA catalytic subunit, suggesting that activation of PKA increases the turnover of GRIP1 protein. The proteasome inhibitors MG132 and lactacystin abolished the PKA-mediated degradation of GRIP1. Using ts20 cells, a temperature-sensitive cell line that contains a thermolabile ubiquitin-activating E1 enzyme, it was confirmed that PKA-mediated degradation of GRIP1 is dependent upon the ubiquitin-proteasome pathway. Coimmunoprecipitation studies of COS-1 cells transfected with expression vectors encoding GRIP1 and ubiquitin using anti-GRIP1 and anti-ubiquitin antibodies showed that the ubiquitination of GRIP1 was increased by overexpression of PKA. Finally, we show that PKA regulates the intracellular distribution pattern of green fluorescent protein-GRIP1 and stimulates recruitment of GRIP1 to subnuclear foci that are colocalized with the proteasome. Taken together, these data demonstrate that GRIP1 is ubiquitinated and degraded through activation of the PKA pathway. This may represent a novel regulatory mechanism whereby hormones down-regulate a nuclear receptor coactivator.
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Affiliation(s)
- Tuyen Hoang
- Hormone Laboratory, Section of Endocrinology, Institute of Medicine, Division of Anatomy and Cell Biology, Department of Biomedicine, University of Bergen and Haukeland University Hospital, Bergen N-5021, Norway
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