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Schlachetzki JC, Saliba SW, Oliveira ACPD. Studying neurodegenerative diseases in culture models. BRAZILIAN JOURNAL OF PSYCHIATRY 2013; 35 Suppl 2:S92-100. [DOI: 10.1590/1516-4446-2013-1159] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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Choudhury KR, Raychaudhuri S, Bhattacharyya NP. Identification of HYPK-interacting proteins reveals involvement of HYPK in regulating cell growth, cell cycle, unfolded protein response and cell death. PLoS One 2012; 7:e51415. [PMID: 23272104 PMCID: PMC3525516 DOI: 10.1371/journal.pone.0051415] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2012] [Accepted: 11/01/2012] [Indexed: 11/18/2022] Open
Abstract
Huntingtin Yeast Two-Hybrid Protein K (HYPK) is an intrinsically unstructured huntingtin (HTT)-interacting protein with chaperone-like activity. To obtain more information about the function(s) of the protein, we identified 27 novel interacting partners of HYPK by pull-down assay coupled with mass spectrometry and, further, 9 proteins were identified by co-localization and co-immunoprecipitation (co-IP) assays. In neuronal cells, (EEF1A1 and HSPA1A), (HTT and LMNB2) and (TP53 and RELA) were identified in complex with HYPK in different experiments. Various Gene Ontology (GO) terms for biological processes, like protein folding (GO: 0006457), response to unfolded protein (GO: 0006986), cell cycle arrest (GO: 0007050), anti-apoptosis (GO: 0006916) and regulation of transcription (GO: 0006355) were significantly enriched with the HYPK-interacting proteins. Cell growth and the ability to refold heat-denatured reporter luciferase were decreased, but cytotoxicity was increased in neuronal cells where HYPK was knocked-down using HYPK antisense DNA construct. The proportion of cells in different phases of cell cycle was also altered in cells with reduced levels of HYPK. These results show that HYPK is involved in several biological processes, possibly through interaction with its partners.
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Affiliation(s)
- Kamalika Roy Choudhury
- Crystallography and Molecular Biology Division, Saha Institute of Nuclear Physics, Kolkata, West Bengal, India
| | - Swasti Raychaudhuri
- Crystallography and Molecular Biology Division, Saha Institute of Nuclear Physics, Kolkata, West Bengal, India
| | - Nitai P. Bhattacharyya
- Crystallography and Molecular Biology Division, Saha Institute of Nuclear Physics, Kolkata, West Bengal, India
- * E-mail:
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53
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The Aggregation of Huntingtin and α-Synuclein. JOURNAL OF BIOPHYSICS 2012; 2012:606172. [PMID: 22899913 PMCID: PMC3412099 DOI: 10.1155/2012/606172] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 02/22/2012] [Revised: 05/15/2012] [Accepted: 05/17/2012] [Indexed: 12/23/2022]
Abstract
Huntington's and Parkinson's diseases are neurodegenerative disorders associated with unusual protein interactions. Although the origin and evolution of these diseases are completely different, characteristic deposits of protein aggregates (huntingtin and α-synuclein resp.), are a common feature in both diseases. After these observations, many studies are performed with both proteins. Some of them try to understand the nature and driving forces of the aggregation process; others try to find a correlation between the genetic and failure in protein function. Finally with the combination of both approaches, it was proposed that possible strategies deal with pathologic aggregation. Unfortunately, if protein aggregation is a cause or a consequence of the neurodegeneration observed in these pathologies, it is still debatable. This paper describes the process of aggregation of two proteins: huntingtin and α synuclein. The characteristics of the aggregation reaction of these proteins have been followed with novel methods both in vivo and in vitro; these studies include both the combination with other proteins and the presence of various chemical compounds. The ultimate goal of this study was to summarize recent findings on protein aggregation and its possible role as a therapeutic target in neurodegenerative diseases and their role in biomaterial science.
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Schrimpe-Rutledge AC, Fontès G, Gritsenko MA, Norbeck AD, Anderson DJ, Waters KM, Adkins JN, Smith RD, Poitout V, Metz TO. Discovery of novel glucose-regulated proteins in isolated human pancreatic islets using LC-MS/MS-based proteomics. J Proteome Res 2012; 11:3520-32. [PMID: 22578083 DOI: 10.1021/pr3002996] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The prevalence of diabetes mellitus is increasing dramatically throughout the world, and the disease has become a major public health issue. The most common form of the disease, type 2 diabetes, is characterized by insulin resistance and insufficient insulin production from the pancreatic beta-cell. Since glucose is the most potent regulator of beta-cell function under physiological conditions, identification of the insulin secretory defect underlying type 2 diabetes requires a better understanding of glucose regulation of human beta-cell function. To this aim, a bottom-up LC-MS/MS-based proteomics approach was used to profile pooled islets from multiple donors under basal (5 mM) or high (15 mM) glucose conditions. Our analysis discovered 256 differentially abundant proteins (∼p < 0.05) after 24 h of high glucose exposure from more than 4500 identified in total. Several novel glucose-regulated proteins were elevated under high glucose conditions, including regulators of mRNA splicing (pleiotropic regulator 1), processing (retinoblastoma binding protein 6), and function (nuclear RNA export factor 1), in addition to neuron navigator 1 and plasminogen activator inhibitor 1. Proteins whose abundances markedly decreased during incubation at 15 mM glucose included Bax inhibitor 1 and synaptotagmin-17. Up-regulation of dicer 1 and SLC27A2 and down-regulation of phospholipase Cβ4 were confirmed by Western blots. Many proteins found to be differentially abundant after high glucose stimulation are annotated as uncharacterized or hypothetical. These findings expand our knowledge of glucose regulation of the human islet proteome and suggest many hitherto unknown responses to glucose that require additional studies to explore novel functional roles.
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Ratovitski T, Chighladze E, Arbez N, Boronina T, Herbrich S, Cole RN, Ross CA. Huntingtin protein interactions altered by polyglutamine expansion as determined by quantitative proteomic analysis. Cell Cycle 2012; 11:2006-21. [PMID: 22580459 DOI: 10.4161/cc.20423] [Citation(s) in RCA: 89] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Huntington disease (HD) is a neurodegenerative disorder caused by an expansion of a polyglutamine repeat within the HD gene product, huntingtin. Huntingtin, a large (347 kDa) protein containing multiple HEAT repeats, acts as a scaffold for protein-protein interactions. Huntingtin-induced toxicity is believed to be mediated by a conformational change in expanded huntingtin, leading to protein misfolding and aggregation, aberrant protein interactions and neuronal cell death. While many non-systematic studies of huntingtin interactions have been reported, they were not designed to identify and quantify the changes in the huntingtin interactome induced by polyglutamine expansion. We used tandem affinity purification and quantitative proteomics to compare and quantify interactions of normal or expanded huntingtin isolated from a striatal cell line. We found that proteins preferentially interacting with expanded huntingtin are enriched for intrinsically disordered proteins, consistent with previously suggested roles of such proteins in neurodegenerative disorders. Our functional analysis indicates that proteins related to energy production, protein trafficking, RNA post-transcriptional modifications and cell death were significantly enriched among preferential interactors of expanded huntingtin. Expanded huntingtin interacted with many mitochondrial proteins, including AIFM1, consistent with a role for mitochondrial dysfunction in HD. Furthermore, expanded huntingtin interacted with the stress granule-associated proteins Caprin-1 and G3BP and redistributed to RNA stress granules under ER-stress conditions. These data demonstrate that a number of key cellular functions and networks may be disrupted by abnormal interactions of expanded huntingtin and highlight proteins and pathways that may be involved in HD cellular pathogenesis and that may serve as therapeutic targets.
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Affiliation(s)
- Tamara Ratovitski
- Division of Neurobiology, Department of Psychiatry, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
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Ghose J, Sinha M, Das E, Jana NR, Bhattacharyya NP. Regulation of miR-146a by RelA/NFkB and p53 in STHdh(Q111)/Hdh(Q111) cells, a cell model of Huntington's disease. PLoS One 2011; 6:e23837. [PMID: 21887328 PMCID: PMC3162608 DOI: 10.1371/journal.pone.0023837] [Citation(s) in RCA: 81] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2010] [Accepted: 07/28/2011] [Indexed: 12/27/2022] Open
Abstract
Huntington's disease (HD) is caused by the expansion of N-terminal polymorphic poly Q stretch of the protein huntingtin (HTT). Deregulated microRNAs and loss of function of transcription factors recruited to mutant HTT aggregates could cause characteristic transcriptional deregulation associated with HD. We observed earlier that expressions of miR-125b, miR-146a and miR-150 are decreased in STHdhQ111/HdhQ111 cells, a model for HD in comparison to those of wild type STHdhQ7/HdhQ7 cells. In the present manuscript, we show by luciferase reporter assays and real time PCR that decreased miR-146a expression in STHdhQ111/HdhQ111 cells is due to decreased expression and activity of p65 subunit of NFkB (RelA/NFkB). By reporter luciferase assay, RT-PCR and western blot analysis, we also show that both miR-150 and miR-125b target p53. This partially explains the up regulation of p53 observed in HD. Elevated p53 interacts with RelA/NFkB, reduces its expression and activity and decreases the expression of miR-146a, while knocking down p53 increases RelA/NFkB and miR-146a expressions. We also demonstrate that expression of p53 is increased and levels of RelA/NFkB, miR-146a, miR-150 and miR-125b are decreased in striatum of R6/2 mice, a mouse model of HD and in cell models of HD. In a cell model, this effect could be reversed by exogenous expression of chaperone like proteins HYPK and Hsp70. We conclude that (i) miR-125b and miR-150 target p53, which in turn regulates RelA/NFkB and miR-146a expressions; (ii) reduced miR-125b and miR-150 expressions, increased p53 level and decreased RelA/NFkB and miR-146a expressions originate from mutant HTT (iii) p53 directly or indirectly regulates the expression of miR-146a. Our observation of interplay between transcription factors and miRNAs using HD cell model provides an important platform upon which further work is to be done to establish if such regulation plays any role in HD pathogenesis.
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Affiliation(s)
- Jayeeta Ghose
- Crystallography and Molecular Biology Division, Saha Institute of Nuclear Physics, Kolkata, West Bengal, India
| | - Mithun Sinha
- Structural Genomics Division, Saha Institute of Nuclear Physics, Kolkata, West Bengal, India
| | - Eashita Das
- Crystallography and Molecular Biology Division, Saha Institute of Nuclear Physics, Kolkata, West Bengal, India
| | - Nihar R. Jana
- Division of Cellular and Molecular Neuroscience, National Brain Research Centre, Manesar, Haryana, India
| | - Nitai P. Bhattacharyya
- Crystallography and Molecular Biology Division, Saha Institute of Nuclear Physics, Kolkata, West Bengal, India
- * E-mail:
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Datta M, Bhattacharyya NP. Regulation of RE1 protein silencing transcription factor (REST) expression by HIP1 protein interactor (HIPPI). J Biol Chem 2011; 286:33759-69. [PMID: 21832040 DOI: 10.1074/jbc.m111.265173] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Earlier we have shown that the proapoptotic protein HIPPI (huntingtin interacting protein 1 (HIP1) protein interactor) along with its molecular partner HIP1 could regulate transcription of the caspase-1 gene. Here we report that RE1-silencing transcription factor/neuron-restrictive silencer factor (REST/NRSF) is a new transcriptional target of HIPPI. HIPPI could bind to the promoter of REST and increased its expression in neuronal as well as non-neuronal cells. Such activation of REST down-regulated expression of REST target genes, such as brain-derived neurotrophic factor (BDNF) or proenkephalin (PENK). The ability of HIPPI to activate REST gene transcription was dependent on HIP1, the nuclear transporter of HIPPI. Using a Huntington disease cell model, we have demonstrated that feeble interaction of HIP1 with mutant huntingtin protein resulted in increased nuclear accumulation of HIPPI and HIP1, leading to higher occupancy of HIPPI at the REST promoter, triggering its transcriptional activation and consequent repression of REST target genes. This novel transcription regulatory mechanism of REST by HIPPI may contribute to the deregulation of transcription observed in the cell model of Huntington disease.
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Affiliation(s)
- Moumita Datta
- Crystallography and Molecular Biology Division, Saha Institute of Nuclear Physics, 1/AF Bidhan Nagar, Kolkata 700 064, India
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Taylor DM, Balabadra U, Xiang Z, Woodman B, Meade S, Amore A, Maxwell MM, Reeves S, Bates GP, Luthi-Carter R, Lowden PAS, Kazantsev AG. A brain-permeable small molecule reduces neuronal cholesterol by inhibiting activity of sirtuin 2 deacetylase. ACS Chem Biol 2011; 6:540-6. [PMID: 21370928 DOI: 10.1021/cb100376q] [Citation(s) in RCA: 102] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Sirtuin 2 (SIRT2) deacetylase-dependent inhibition mediates neuroprotective reduction of cholesterol biosynthesis in an in vitro Huntington's disease model. This study sought to identify the first brain-permeable SIRT2 inhibitor and to characterize its cholesterol-reducing properties in neuronal models. Using biochemical sirtuin deacetylation assays, we screened a brain-permeable in silico compound library, yielding 3-(1-azepanylsulfonyl)-N-(3-bromphenyl)benzamide as the most potent and selective SIRT2 inhibitor. Pharmacokinetic studies demonstrated brain-permeability but limited metabolic stability of the selected candidate. In accordance with previous observations, this SIRT2 inhibitor stimulated cytoplasmic retention of sterol regulatory element binding protein-2 and subsequent transcriptional downregulation of cholesterol biosynthesis genes, resulting in reduced total cholesterol in primary striatal neurons. Furthermore, the identified inhibitor reduced cholesterol in cultured naïve neuronal cells and brain slices from wild-type mice. The outcome of this study provides a clear opportunity for lead optimization and drug development, targeting metabolic dysfunctions in CNS disorders where abnormal cholesterol homeostasis is implicated.
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Affiliation(s)
- David M. Taylor
- Brain Mind Institute, Ecole Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland
| | - Uma Balabadra
- Department of Biological Sciences, Birkbeck, University of London, Malet Street, London WC1E 7HX, U.K
| | - Zhongmin Xiang
- MassGeneral Institute for Neurodegenerative Disease, Massachusetts General Hospital, Charlestown, Massachusetts 02129, United States
| | - Ben Woodman
- Department of Medical and Molecular Genetics, King’s College London, Eighth Floor Tower Wing, Guy’s Hospital, Great Maze Pond, London SE1 9RT, U.K
| | - Sarah Meade
- MassGeneral Institute for Neurodegenerative Disease, Massachusetts General Hospital, Charlestown, Massachusetts 02129, United States
| | - Allison Amore
- MassGeneral Institute for Neurodegenerative Disease, Massachusetts General Hospital, Charlestown, Massachusetts 02129, United States
| | - Michele M. Maxwell
- MassGeneral Institute for Neurodegenerative Disease, Massachusetts General Hospital, Charlestown, Massachusetts 02129, United States
- Harvard Medical School, Boston, Massachusetts 02129, United States
| | - Steven Reeves
- MassGeneral Institute for Neurodegenerative Disease, Massachusetts General Hospital, Charlestown, Massachusetts 02129, United States
| | - Gillian P. Bates
- Department of Medical and Molecular Genetics, King’s College London, Eighth Floor Tower Wing, Guy’s Hospital, Great Maze Pond, London SE1 9RT, U.K
| | - Ruth Luthi-Carter
- Brain Mind Institute, Ecole Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland
| | - Philip A. S. Lowden
- Department of Biological Sciences, Birkbeck, University of London, Malet Street, London WC1E 7HX, U.K
| | - Aleksey G. Kazantsev
- MassGeneral Institute for Neurodegenerative Disease, Massachusetts General Hospital, Charlestown, Massachusetts 02129, United States
- Harvard Medical School, Boston, Massachusetts 02129, United States
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Szolajska E, Chroboczek J. Faithful chaperones. Cell Mol Life Sci 2011; 68:3307-22. [PMID: 21655914 PMCID: PMC3181412 DOI: 10.1007/s00018-011-0740-4] [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: 03/11/2011] [Revised: 05/19/2011] [Accepted: 05/23/2011] [Indexed: 12/01/2022]
Abstract
This review describes the properties of some rare eukaryotic chaperones that each assist in the folding of only one target protein. In particular, we describe (1) the tubulin cofactors, (2) p47, which assists in the folding of collagen, (3) α-hemoglobin stabilizing protein (AHSP), (4) the adenovirus L4-100 K protein, which is a chaperone of the major structural viral protein, hexon, and (5) HYPK, the huntingtin-interacting protein. These various-sized proteins (102–1,190 amino acids long) are all involved in the folding of oligomeric polypeptides but are otherwise functionally unique, as they each assist only one particular client. This raises a question regarding the biosynthetic cost of the high-level production of such chaperones. As the clients of faithful chaperones are all abundant proteins that are essential cellular or viral components, it is conceivable that this necessary metabolic expenditure withstood evolutionary pressure to minimize biosynthetic costs. Nevertheless, the complexity of the folding pathways in which these chaperones are involved results in error-prone processes. Several human disorders associated with these chaperones are discussed.
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Affiliation(s)
- Ewa Szolajska
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Pawinskiego 5a, 02106 Warsaw, Poland
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60
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Abstract
It has been more than 17 years since the causative mutation for Huntington's disease was discovered as the expansion of the triplet repeat in the N-terminal portion of the Huntingtin (HTT) gene. In the intervening time, researchers have discovered a great deal about Huntingtin's involvement in a number of cellular processes. However, the role of Huntingtin in the key pathogenic mechanism leading to neurodegeneration in the disease process has yet to be discovered. Here, we review the body of knowledge that has been uncovered since gene discovery and include discussions of the HTT gene, CAG triplet repeat expansion, HTT expression, protein features, posttranslational modifications, and many of its known protein functions and interactions. We also highlight potential pathogenic mechanisms that have come to light in recent years.
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Affiliation(s)
- Karen N McFarland
- Department of Neurology, University of Florida, Gainesville, FL 32610-0236, USA.
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Langbehn DR, Hayden M, Paulsen JS. CAG-repeat length and the age of onset in Huntington disease (HD): a review and validation study of statistical approaches. Am J Med Genet B Neuropsychiatr Genet 2010; 153B:397-408. [PMID: 19548255 PMCID: PMC3048807 DOI: 10.1002/ajmg.b.30992] [Citation(s) in RCA: 251] [Impact Index Per Article: 17.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
CAG-repeat length in the gene for HD is inversely correlated with age of onset (AOO). A number of statistical models elucidating the relationship between CAG length and AOO have recently been published. In the present article, we review the published formulae, summarize essential differences in participant sources, statistical methodologies, and predictive results. We argue that unrepresentative sampling and failure to use appropriate survival analysis methodology may have substantially biased much of the literature. We also explain why the survival analysis perspective is necessary if any such model is to undergo prospective validation. We use prospective diagnostic data from the PREDICT-HD longitudinal study of CAG-expanded participants to test conditional predictions derived from two survival models of AOO of HD. A prior model of the relationship of CAG and AOO originally published by Langbehn et al. yields reasonably accurate predictions, while a similar model by Gutierrez and MacDonald substantially overestimates diagnosis risk for all but the highest risk participants in this sample. The Langbehn et al. model appears accurate enough to have substantial utility in various research contexts. We also emphasize remaining caveats, many of which are relevant for any direct application to genetic counseling.
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Affiliation(s)
- Douglas R. Langbehn
- Department of Psychiatry, Carver College of Medicine, and Biostatistics (secondary), University of Iowa, Iowa City, Iowa, USA, Department of Biostatistics (secondary), School of Public Health, University of Iowa, Iowa City, Iowa, USA
| | - Michael Hayden
- Centre for Molecular Medicine and Therapeutics, University of British Columbia, Vancouver, British Columbia, Canada
| | - Jane S. Paulsen
- Department of Psychiatry, Carver College of Medicine, and Biostatistics (secondary), University of Iowa, Iowa City, Iowa, USA
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The chaperone-like protein HYPK acts together with NatA in cotranslational N-terminal acetylation and prevention of Huntingtin aggregation. Mol Cell Biol 2010; 30:1898-909. [PMID: 20154145 DOI: 10.1128/mcb.01199-09] [Citation(s) in RCA: 106] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
The human NatA protein N(alpha)-terminal-acetyltransferase complex is responsible for cotranslational N-terminal acetylation of proteins with Ser, Ala, Thr, Gly, and Val N termini. The NatA complex is composed of the catalytic subunit hNaa10p (hArd1) and the auxiliary subunit hNaa15p (hNat1/NATH). Using immunoprecipitation coupled with mass spectrometry, we identified endogenous HYPK, a Huntingtin (Htt)-interacting protein, as a novel stable interactor of NatA. HYPK has chaperone-like properties preventing Htt aggregation. HYPK, hNaa10p, and hNaa15p were associated with polysome fractions, indicating a function of HYPK associated with the NatA complex during protein translation. Knockdown of both hNAA10 and hNAA15 decreased HYPK protein levels, possibly indicating that NatA is required for the stability of HYPK. The biological importance of HYPK was evident from HYPK-knockdown HeLa cells displaying apoptosis and cell cycle arrest in the G(0)/G(1) phase. Knockdown of HYPK or hNAA10 resulted in increased aggregation of an Htt-enhanced green fluorescent protein (Htt-EGFP) fusion with expanded polyglutamine stretches, suggesting that both HYPK and NatA prevent Htt aggregation. Furthermore, we demonstrated that HYPK is required for N-terminal acetylation of the known in vivo NatA substrate protein PCNP. Taken together, the data indicate that the physical interaction between HYPK and NatA seems to be of functional importance both for Htt aggregation and for N-terminal acetylation.
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Intrinsic Disorder in Proteins Associated with Neurodegenerative Diseases. PROTEIN FOLDING AND MISFOLDING: NEURODEGENERATIVE DISEASES 2008. [DOI: 10.1007/978-1-4020-9434-7_2] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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Truant R, Atwal RS, Desmond C, Munsie L, Tran T. Huntington's disease: revisiting the aggregation hypothesis in polyglutamine neurodegenerative diseases. FEBS J 2008; 275:4252-62. [PMID: 18637947 DOI: 10.1111/j.1742-4658.2008.06561.x] [Citation(s) in RCA: 84] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
After the successful cloning of the first gene for a polyglutamine disease in 1991, the expanded polyglutamine tract in the nine polyglutamine disease proteins became an obvious therapeutic target. Early hypotheses were that misfolded, precipitated protein could be a universal pathogenic mechanism. However, new data are accumulating on Huntington's disease and other polyglutamine diseases that appear to contradict the toxic aggregate hypothesis. Recent data suggest that the toxic species of protein in these diseases may be soluble mutant conformers, and that the protein context of expanded polyglutamine is critical to understanding disease specificity. Here we discuss recent publications that define other important therapeutic targets for polyglutamine-mediated neurodegeneration related to the context of the expanded polyglutamine tract in the disease protein.
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Affiliation(s)
- Ray Truant
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, Canada.
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Meistertzheim AL, Tanguy A, Moraga D, Thébault MT. Identification of differentially expressed genes of the Pacific oyster Crassostrea gigas exposed to prolonged thermal stress. FEBS J 2007; 274:6392-402. [PMID: 18005253 DOI: 10.1111/j.1742-4658.2007.06156.x] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Groups of oysters (Crassostrea gigas) were exposed to 25 degrees C for 24 days (controls to 13 degrees C) to explore the biochemical and molecular pathways affected by prolonged thermal stress. This temperature is 4 degrees C above the summer seawater temperature encountered in western Brittany, France where the animals were collected. Suppression subtractive hybridization was used to identify specific up- and downregulated genes in gill and mantle tissues after 7-10 and 24 days of exposure. The resulting libraries contain 858 different sequences that potentially represent highly expressed genes in thermally stressed oysters. Expression of 17 genes identified in these libraries was studied using real-time PCR in gills and mantle at different time points over the course of the thermal stress. Differential gene expression levels were much higher in gills than in the mantle, showing that gills are more sensitive to thermal stress. Expression of most transcripts (mainly heat shock proteins and genes involved in cellular homeostasis) showed a high and rapid increase at 3-7 days of exposure, followed by a decrease at 14 days, and a second, less-pronounced increase at 17-24 days. A slow-down in protein synthesis occurred after 24 days of thermal stress.
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Affiliation(s)
- Anne-Leila Meistertzheim
- Laboratoire des Sciences de l'Environnement Marin, Institut Universitaire Européan de la Mer, Université de Bretagne occidentale, Plouzané, France
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