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O’Rourke JG, Gareau JR, Ochaba J, Song W, Raskó T, Reverter D, Lee J, Monteys AM, Pallos J, Mee L, Vashishtha M, Apostol BL, Nicholson TP, Illes K, Zhu YZ, Dasso M, Bates GP, Difiglia M, Davidson B, Wanker EE, Marsh JL, Lima CD, Steffan JS, Thompson LM. SUMO-2 and PIAS1 modulate insoluble mutant huntingtin protein accumulation. Cell Rep 2013; 4:362-75. [PMID: 23871671 PMCID: PMC3931302 DOI: 10.1016/j.celrep.2013.06.034] [Citation(s) in RCA: 81] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2013] [Revised: 04/03/2013] [Accepted: 06/24/2013] [Indexed: 11/19/2022] Open
Abstract
A key feature in Huntington disease (HD) is the accumulation of mutant Huntingtin (HTT) protein, which may be regulated by posttranslational modifications. Here, we define the primary sites of SUMO modification in the amino-terminal domain of HTT, show modification downstream of this domain, and demonstrate that HTT is modified by the stress-inducible SUMO-2. A systematic study of E3 SUMO ligases demonstrates that PIAS1 is an E3 SUMO ligase for both HTT SUMO-1 and SUMO-2 modification and that reduction of dPIAS in a mutant HTT Drosophila model is protective. SUMO-2 modification regulates accumulation of insoluble HTT in HeLa cells in a manner that mimics proteasome inhibition and can be modulated by overexpression and acute knockdown of PIAS1. Finally, the accumulation of SUMO-2-modified proteins in the insoluble fraction of HD postmortem striata implicates SUMO-2 modification in the age-related pathogenic accumulation of mutant HTT and other cellular proteins that occurs during HD progression.
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Affiliation(s)
- Jacqueline Gire O’Rourke
- Department of Biological Chemistry, University of California, Irvine, Irvine, CA 92697, USA
- Department of Psychiatry and Human Behavior, University of California, Irvine, Irvine, CA 92697, USA
- Institute for Memory Impairments and Neurological Disorders, University of California, Irvine, Irvine, CA 92697, USA
| | - Jaclyn R. Gareau
- Structural Biology Program, Sloan-Kettering Institute, New York, NY 10065, USA
| | - Joseph Ochaba
- Institute for Memory Impairments and Neurological Disorders, University of California, Irvine, Irvine, CA 92697, USA
- Department of Neurobiology and Behavior, University of California, Irvine, Irvine, CA 92697, USA
| | - Wan Song
- Department of Developmental and Cell Biology, University of California, Irvine, Irvine, CA 92697, USA
| | - Tamás Raskó
- Max-Delbrueck-Center for Molecular Medicine, 13125 Berlin, Germany
| | - David Reverter
- Structural Biology Program, Sloan-Kettering Institute, New York, NY 10065, USA
| | - John Lee
- Departments of Internal Medicine, Neurology, and Molecular Physiology and Biophysics, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
| | - Alex Mas Monteys
- Departments of Internal Medicine, Neurology, and Molecular Physiology and Biophysics, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
| | - Judit Pallos
- Department of Developmental and Cell Biology, University of California, Irvine, Irvine, CA 92697, USA
| | - Lisa Mee
- Department of Psychiatry and Human Behavior, University of California, Irvine, Irvine, CA 92697, USA
| | - Malini Vashishtha
- Department of Psychiatry and Human Behavior, University of California, Irvine, Irvine, CA 92697, USA
- Institute for Memory Impairments and Neurological Disorders, University of California, Irvine, Irvine, CA 92697, USA
| | - Barbara L. Apostol
- Department of Psychiatry and Human Behavior, University of California, Irvine, Irvine, CA 92697, USA
| | | | - Katalin Illes
- Department of Psychiatry and Human Behavior, University of California, Irvine, Irvine, CA 92697, USA
| | - Ya-Zhen Zhu
- Department of Psychiatry and Human Behavior, University of California, Irvine, Irvine, CA 92697, USA
| | - Mary Dasso
- Laboratory of Gene Regulation and Development, National Institute of Child Health and Development, National Institutes of Health, Bethesda, MD 20892, USA
| | - Gillian P. Bates
- Department of Medical and Molecular Genetics, King’s College London School of Medicine, London WC2R 2LS, UK
| | - Marian Difiglia
- Department of Neurology, Massachusetts General Hospital and Harvard Medical School, Charlestown, MA 02129, USA
| | - Beverly Davidson
- Departments of Internal Medicine, Neurology, and Molecular Physiology and Biophysics, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
| | - Erich E. Wanker
- Max-Delbrueck-Center for Molecular Medicine, 13125 Berlin, Germany
| | - J. Lawrence Marsh
- Department of Developmental and Cell Biology, University of California, Irvine, Irvine, CA 92697, USA
| | - Christopher D. Lima
- Structural Biology Program, Sloan-Kettering Institute, New York, NY 10065, USA
| | - Joan S. Steffan
- Department of Psychiatry and Human Behavior, University of California, Irvine, Irvine, CA 92697, USA
- Institute for Memory Impairments and Neurological Disorders, University of California, Irvine, Irvine, CA 92697, USA
| | - Leslie M. Thompson
- Department of Biological Chemistry, University of California, Irvine, Irvine, CA 92697, USA
- Department of Psychiatry and Human Behavior, University of California, Irvine, Irvine, CA 92697, USA
- Institute for Memory Impairments and Neurological Disorders, University of California, Irvine, Irvine, CA 92697, USA
- Department of Neurobiology and Behavior, University of California, Irvine, Irvine, CA 92697, USA
- Correspondence:
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Cooperative roles of fish protein kinase containing Z-DNA binding domains and double-stranded RNA-dependent protein kinase in interferon-mediated antiviral response. J Virol 2011; 85:12769-80. [PMID: 21937641 DOI: 10.1128/jvi.05849-11] [Citation(s) in RCA: 67] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The double-stranded RNA (dsRNA)-dependent protein kinase (PKR) inhibits protein synthesis by phosphorylating eukaryotic translation initiation factor 2α (eIF2α). In fish species, in addition to PKR, there exists a PKR-like protein kinase containing Z-DNA binding domains (PKZ). However, the antiviral role of fish PKZ and the functional relationship between fish PKZ and PKR remain unknown. Here we confirmed the coexpression of fish PKZ and PKR proteins in Carassius auratus blastula embryonic (CAB) cells and identified them as two typical interferon (IFN)-inducible eIF2α kinases, both of which displayed an ability to inhibit virus replication. Strikingly, fish IFN or all kinds of IFN stimuli activated PKZ and PKR to phosphorylated eIF2α. Overexpression of both fish kinases together conferred much more significant inhibition of virus replication than overexpression of either protein, whereas morpholino knockdown of both made fish cells more vulnerable to virus infection than knockdown of either. The antiviral ability of fish PKZ was weaker than fish PKR, which correlated with its lower ability to phosphorylate eIF2α than PKR. Moreover, the independent association of fish PKZ or PKR reveals that each of them formed homodimers and that fish PKZ phosphorylated eIF2α independently on fish PKR and vice versa. These results suggest that fish PKZ and PKR play a nonredundant but cooperative role in IFN antiviral response.
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Shang H, Li Q, Feng G, Cui Z. Identification and characterization of alternative promoters, transcripts and protein isoforms of zebrafish R2 gene. PLoS One 2011; 6:e24089. [PMID: 21887375 PMCID: PMC3161108 DOI: 10.1371/journal.pone.0024089] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2011] [Accepted: 08/04/2011] [Indexed: 12/17/2022] Open
Abstract
Ribonucleotide reductase (RNR) is the rate-limiting enzyme in the de novo synthesis of deoxyribonucleoside triphosphates. Expression of RNR subunits is closely associated with DNA replication and repair. Mammalian RNR M2 subunit (R2) functions exclusively in DNA replication of normal cells due to its S phase-specific expression and late mitotic degradation. Herein, we demonstrate the control of R2 expression through alternative promoters, splicing and polyadenylation sites in zebrafish. Three functional R2 promoters were identified to generate six transcript variants with distinct 5′ termini. The proximal promoter contains a conserved E2F binding site and two CCAAT boxes, which are crucial for the transcription of R2 gene during cell cycle. Activity of the distal promoter can be induced by DNA damage to generate four transcript variants through alternative splicing. In addition, two novel splice variants were found to encode distinct N-truncated R2 isoforms containing residues for enzymatic activity but no KEN box essential for its proteolysis. These two N-truncated R2 isoforms remained in the cytoplasm and were able to interact with RNR M1 subunit (R1). Thus, our results suggest that multilayered mechanisms control the differential expression and function of zebrafish R2 gene during cell cycle and under genotoxic stress.
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Affiliation(s)
- Hanqiao Shang
- The Key Laboratory of Aquatic Biodiversity and Conservation of Chinese Academy of Sciences, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, Hubei, People's Republic of China
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Xiao W, Ai J, Habermacher G, Volpert O, Yang X, Zhang AY, Hahn J, Cai X, Wang Z. U19/Eaf2 binds to and stabilizes von hippel-lindau protein. Cancer Res 2009; 69:2599-606. [PMID: 19258512 DOI: 10.1158/0008-5472.can-08-2595] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Studies have firmly established a key regulatory role for the tumor suppressor pVHL in the regulation of the vascular system and normal spermatogenesis. Here, we report that knockout of the newly identified tumor suppressor U19/Eaf2 also caused vascular system abnormalities and aspermatogenesis, suggesting a potential link between U19/Eaf2 and pVHL. Coimmunoprecipitation and in vitro binding assays showed an association between U19/Eaf2 and pVHL, whereas deletion mutagenesis revealed the requirement of the NH(2) terminus of U19/Eaf2 and both the alpha and beta domains of pVHL for this binding. U19/Eaf2 stabilizes pVHL, as shown by protein stability and pulse-chase studies. Testes and mouse embryonic fibroblasts (MEF) derived from U19/Eaf2 knockout mice expressed reduced levels of pVHL, indicating that full in vivo expression of pVHL indeed requires U19/Eaf2. As expected, U19/Eaf2 knockout MEF cells exhibited an increased level and activity of hypoxia-inducible factor 1alpha (HIF1alpha), a protein typically regulated via a pVHL-mediated degradation pathway. Furthermore, angiogenesis in a Matrigel plug assay was significantly increased in U19/Eaf2 knockout mice. The above observations argue that U19/Eaf2 can modulate HIF1alpha and angiogenesis, possibly via direct binding and stabilization of pVHL.
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Affiliation(s)
- Wuhan Xiao
- Department of Urology and University of Pittsburgh Cancer Institute, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
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Hall AB, Jura N, DaSilva J, Jang YJ, Gong D, Bar-Sagi D. hSpry2 is targeted to the ubiquitin-dependent proteasome pathway by c-Cbl. Curr Biol 2003; 13:308-14. [PMID: 12593796 DOI: 10.1016/s0960-9822(03)00086-1] [Citation(s) in RCA: 115] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Sprouty was originally identified in a genetic screen in Drosophila as an antagonist of fibroblast (FGF) and epidermal growth factor (EGF) signaling. Subsequently, four vertebrate homologs were discovered; among these, the human homolog Sprouty 2 (hSpry2) contains the highest degree of sequence homology to the Drosophila protein. It has been shown that hSpry2 interacts directly with c-Cbl, an E3-ubiquitin ligase, which promotes the downregulation of receptor tyrosine kinases (RTKs). In this study, we have investigated the functional consequences of the association between hSpry2 and c-Cbl. We have found that hSpry2 is ubiquitinated by c-Cbl in an EGF-dependent manner. EGF stimulation induces the tyrosine phosphorylation of hSpry2, which in turn enhances the interaction of hSpry2 with c-Cbl. The c-Cbl-mediated ubiquitination of hSpry2 targets the protein for degradation by the 26S proteasome. An enhanced proteolytic degradation of hSpry2 is also observed in response to FGF stimulation. The FGF-induced degradation of hSpry2 limits the duration of the inhibitory effect of hSpry2 on extracellular signal-regulated kinase (ERK) activation and enables the cells to recover their sensitivity to FGF stimulation. Our results indicate that the interaction of hSpry2 with c-Cbl might serve as a mechanism for the downregulation of hSpry2 during receptor tyrosine kinase signaling.
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Affiliation(s)
- Amy B Hall
- Department of Molecular Genetics and Microbiology, State University of New York at Stony Brook, Stony Brook, NY 11794-5222, USA
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