151
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Benayoun BA, Veitia RA. A post-translational modification code for transcription factors: sorting through a sea of signals. Trends Cell Biol 2009; 19:189-97. [PMID: 19328693 DOI: 10.1016/j.tcb.2009.02.003] [Citation(s) in RCA: 97] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2009] [Revised: 02/11/2009] [Accepted: 02/19/2009] [Indexed: 11/29/2022]
Abstract
Cellular responses to environmental or physiological cues rely on transduction pathways that must ensure discrimination between different signals. These cascades 'crosstalk' and lead to a combinatorial regulation. This often results in different combinations of post-translational modifications (PTMs) on target proteins, which might act as a molecular barcode. Although appealing, the idea of the existence of such a code for transcription factors is debated. Using general arguments and recent evidence, we propose that a PTM code is not only possible but necessary in the context of transcription factors regulating multiple processes. Thus, the coding potential of PTM combinations should both provide a further layer of information integration from several transduction pathways and warrant highly specific cellular outputs.
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Affiliation(s)
- Bérénice A Benayoun
- Institut Jacques Monod, Bâtiment Buffon, 15 Rue Hélène Brion, Paris Cedex 13, France
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152
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Sarge KD, Park-Sarge OK. Mitotic bookmarking of formerly active genes: keeping epigenetic memories from fading. Cell Cycle 2009; 8:818-23. [PMID: 19221503 PMCID: PMC2748302 DOI: 10.4161/cc.8.6.7849] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
In order for cell lineages to be maintained, daughter cells must have the same patterns of gene expression as the cells from which they were divided so that they can have the same phenotypes. However, during mitosis transcription ceases, chromosomal DNA is compacted, and most sequence-specific binding factors dissociate from DNA, making it difficult to understand how the "memory" of gene expression patterns is remembered and propagated to daughter cells. The process of remembering patterns of active gene expression during mitosis for transmission to daughter cells is called gene bookmarking. Here we discuss current knowledge concerning the factors and mechanisms involved in mediating gene bookmarking, including recent results on the mechanism by which the general transcription factor TBP participates in the mitotic bookmarking of formerly active genes.
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Affiliation(s)
- Kevin D Sarge
- Department of Molecular and Cellular Biochemistry, University of Kentucky, Lexington, Kentucky 40536, USA.
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153
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Mkaddem SB, Werts C, Goujon JM, Bens M, Pedruzzi E, Ogier-Denis E, Vandewalle A. Heat shock protein gp96 interacts with protein phosphatase 5 and controls toll-like receptor 2 (TLR2)-mediated activation of extracellular signal-regulated kinase (ERK) 1/2 in post-hypoxic kidney cells. J Biol Chem 2009; 284:12541-9. [PMID: 19265198 DOI: 10.1074/jbc.m808376200] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Ischemia/reperfusion injury (IRI) induces an innate immune response, leading to an inflammatory reaction and tissue damage that have been attributed to engagement of the Toll-like receptor (TLR) 2 and 4. However, the respective roles of TLR2 and/or TLR4 in mediating downstream activation of mitogen-activated protein kinase (MAPK) pathways during IRI have not been fully elucidated. Here we show that extracellular signal-regulated kinase (ERK)1/2 is activated in both intact kidneys and cultured renal tubule epithelial cells (RTECs) from wildtype and Tlr4 knockout mice, but not those from Tlr2 knockout mice subjected to transient ischemia. Geldanamycin (GA), an inhibitor of heat shock protein 90 and reticulum endoplasmic-resident gp96, and gp96 mRNA silencing (siRNA), did not affect ERK1/2 activation in either post-hypoxic wild-type or Tlr4-deficient RTECs, but did restore its activation in post-hypoxic Tlr2-deficient RTECs. Immunoprecipitation studies revealed that gp96 co-immunoprecipitates with the serine-threonine protein phosphatase 5 (PP5), identified as a negative modulator of the mitogen extracellular kinase (MEK)-ERK pathway, in unstressed wild-type and post-hypoxic Tlr2-deficient RTECs. In contrast, PP5 co-immunoprecipitation with gp96 was strikingly reduced in post-hypoxic wild-type RTECs, suggesting that the inactivation of PP5 resulting from the dissociation of PP5 from gp96 allows the activation of ERK1/2 to occur. Inhibition of PP5 by okadaic acid, and Pp5 siRNA also restored TLR2-mediated phosphorylation of ERK1/2, and apoptosis signal-regulating kinase 1 (ASK1)/c-Jun N-terminal kinase (JNK)-mediated apoptosis in post-hypoxic Tlr2-deficient RTECs. These findings indicate that gp96 interacts with PP5 and controls TLR2-mediated induction of ERK1/2 in post-hypoxic renal tubule cells.
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Affiliation(s)
- Sanae Ben Mkaddem
- INSERM U773, Centre de Recherche Biomédicale Bichat-Beaujon CRB3, UFR de Médecine Xavier Bichat, Université Paris 7-Denis Diderot, Site Bichat, BP 416, F-75870 Paris Cedex 18, France
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154
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Yamamoto N, Takemori Y, Sakurai M, Sugiyama K, Sakurai H. Differential recognition of heat shock elements by members of the heat shock transcription factor family. FEBS J 2009; 276:1962-74. [DOI: 10.1111/j.1742-4658.2009.06923.x] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
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155
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Hou Y, Zou J. Delivery of HSF1(+) protein using HIV-1 TAT protein transduction domain. Mol Biol Rep 2009; 36:2271-7. [PMID: 19190998 DOI: 10.1007/s11033-008-9444-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2008] [Accepted: 12/22/2008] [Indexed: 10/21/2022]
Abstract
HSF1 is the major transcription factor of HSPs (heat shock proteins) in response to various stresses. Wild type HSF1 (heat shock transcriptional factor 1) is normally inactive, while a constitutively active form of HSF1 (HSF1(+)) can activate downstream HSP expression in the absence of stresses. Here we generated the eukaryotic vectors that expresses HSF1(+) fusion proteins, and found that HSF1(+)-TAT fusion protein was expressed and activated HSP expression. TAT, as a trans-acting factor of HIV-1, has been demonstrated to deliver functional cargo protein into living cells. HSF1(+)-TAT fusion protein was expressed in E. coli, purified, incubated with A549 cells for 8 h, Western blot analysis and luciferase reporter assay showed that HSF1(+) fusion protein was delivered into A549 cells successfully, and the accumulation of HSF1(+)-TAT fusion protein in A549 cells up-regulated HSP70 expression.
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Affiliation(s)
- Yonghui Hou
- Guangzhou Institute of Biomedicine and Health (GIBH), Chinese Academy of Sciences, 510663 Guangzhou, China
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156
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Evans TG, Somero GN. A microarray-based transcriptomic time-course of hyper- and hypo-osmotic stress signaling events in the euryhaline fish Gillichthys mirabilis: osmosensors to effectors. ACTA ACUST UNITED AC 2009; 211:3636-49. [PMID: 18978229 DOI: 10.1242/jeb.022160] [Citation(s) in RCA: 89] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Cells respond to changes in osmolality with compensatory adaptations that re-establish ion homeostasis and repair disturbed aspects of cell structure and function. These physiological processes are highly complex, and require the coordinated activities of osmosensing, signal transducing and effector molecules. Although the critical role of effector proteins such as Na+, K+-ATPases and Na+/K+/Cl(-) co-transporters during osmotic stress are well established, comparatively little information is available regarding the identity or expression of the osmosensing and signal transduction genes that may govern their activities. To better resolve this issue, a cDNA microarray consisting of 9207 cDNA clones was used to monitor gene expression changes in the gill of the euryhaline fish Gillichthys mirabilis exposed to hyper- and hypo-osmotic stress. We successfully annotated 168 transcripts differentially expressed during the first 12 h of osmotic stress exposure. Functional classifications of genes encoding these transcripts reveal that a variety of biological processes are affected. However, genes participating in cell signaling events were the dominant class of genes differentially expressed during both hyper- and hypo-osmotic stress. Many of these genes have had no previously reported role in osmotic stress adaptation. Subsequent analyses used the novel expression patterns generated in this study to place genes within the context of osmotic stress sensing, signaling and effector events. Our data indicate multiple major signaling pathways work in concert to modify diverse effectors, and that these molecules operate within a framework of regulatory proteins.
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Affiliation(s)
- Tyler G Evans
- Hopkins Marine Station, Stanford University, Pacific Grove, CA 93950, USA.
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157
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Schibler U. The 2008 Pittendrigh/Aschoff Lecture: Peripheral Phase Coordination in the Mammalian Circadian Timing System. J Biol Rhythms 2009; 24:3-15. [DOI: 10.1177/0748730408329383] [Citation(s) in RCA: 65] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The mammalian timing system is composed of a bodywide web of cell-autonomous and self-sustained oscillators. A master clock in the SCN synchronizes peripheral clocks through yet poorly understood molecular signaling pathways. In this lecture I shall present some of the experimental approaches we are employing to elucidate signaling routes through which the SCN may phase entrain peripheral clocks. These attempts unveiled several candidate pathways worth pursuing in future studies, including signaling through nuclear receptors, cytoskeleton components, Ca2+, fibroblast growth factors, ubiquitin ligases, Sirtuin 1 (a redox-sensing histone deacetylase), RNA binding proteins, and body temperature.
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Affiliation(s)
- Ueli Schibler
- Department of Molecular Biology & NCCR Frontiers in Genetics, Sciences, University of Geneva, Geneva, Switzerland,
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158
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Truettner JS, Hu K, Liu CL, Dietrich WD, Hu B. Subcellular stress response and induction of molecular chaperones and folding proteins after transient global ischemia in rats. Brain Res 2009; 1249:9-18. [PMID: 18996359 PMCID: PMC2670784 DOI: 10.1016/j.brainres.2008.10.032] [Citation(s) in RCA: 65] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2008] [Revised: 10/01/2008] [Accepted: 10/10/2008] [Indexed: 11/16/2022]
Abstract
Brain ischemia induces the toxic accumulation of unfolded proteins in vulnerable neurons. This cellular event can trigger the unfolded protein response (UPR) and activate the expression of a number of genes involved in pro-survival pathways. One of the pro-survival pathways involves the sequestration and elimination of misfolded and aggregated proteins. Recent evidence suggests that the endoplasmic reticulum (ER), mitochondria, and cytoplasm respond individually to the accumulation of unfolded proteins by induction of organelle specific molecular chaperones and folding enzymes. This study utilized a rat model of transient (15 min) global ischemia (2-vessel occlusion) to investigate the regional and temporal induction of some of these key stress proteins after ischemia. Electron microscopy demonstrated that visible protein aggregates accumulated predominately in the cytoplasm. We used in situ hybridization (forebrain structures) and western blot (hippocampus) analysis to measure changes in expression of heat shock protein 70 (HSP70 cytoplasmic), HSP60 (mitochondrial), ER luminal proteins glucose response proteins GRP78 and GRP94, protein disulphide isomerase (PDI), homocysteine-inducible, endoplasmic reticulum stress-inducible protein (HERP), and calnexin. Induction of mRNA for HSP70 occurred earlier (beginning at 30 min) and at a higher level relative to the delayed (4-24 h) and more moderate induction of mRNAs for mitochondrial matrix HSP60 and the ER lumen HERP, GRP78, GRP94, calnexin and PDI. Increases in hippocampal proteins were observed at 4 h (HSP70) and 24 h (HSP60, GRP78, GRP94) after reperfusion. These results demonstrate that after a transient ischemic insult, the subcellular responses to the accumulation of unfolded proteins varies between cellular compartments and are most prevalent in the cytoplasm and, to a lesser degree, in the mitochondrial matrix and ER lumen.
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Affiliation(s)
- Jessie S Truettner
- Department of Neurological Surgery, The Miami Project to Cure Paralysis, University of Miami Miller School of Medicine, Miami, FL 33136, USA
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159
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Examination of cadmium-induced expression of the small heat shock protein gene, hsp30, in Xenopus laevis A6 kidney epithelial cells. Comp Biochem Physiol A Mol Integr Physiol 2009; 152:91-9. [DOI: 10.1016/j.cbpa.2008.09.006] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2008] [Revised: 09/02/2008] [Accepted: 09/03/2008] [Indexed: 12/19/2022]
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160
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Goodrich JA, Kugel JF. From bacteria to humans, chromatin to elongation, and activation to repression: The expanding roles of noncoding RNAs in regulating transcription. Crit Rev Biochem Mol Biol 2009; 44:3-15. [PMID: 19107624 PMCID: PMC2659850 DOI: 10.1080/10409230802593995] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Noncoding RNAs (ncRNAs) have emerged as key regulators of transcription, often functioning as trans-acting factors akin to prototypical protein transcriptional regulators. Inside cells, ncRNAs are now known to control transcription of single genes as well as entire transcriptional programs in response to developmental and environmental cues. In doing so, they target nearly all levels of the transcription process from regulating chromatin structure through controlling transcript elongation. Moreover, trans-acting ncRNA transcriptional regulators have been found in organisms as diverse as bacteria and humans. With the recent discovery that much of the DNA in genomes is transcribed into ncRNAs with yet unknown function, it is likely that future studies will reveal many more ncRNA regulators of transcription.
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Affiliation(s)
- James A Goodrich
- Department of Chemistry and Biochemistry, University of Colorado at Boulder, 80309-0215, USA.
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161
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Singh IS, Shah NG, Almutairy E, Hasday JD. Role of HSF1 in Infectious Disease. HEAT SHOCK PROTEINS 2009. [DOI: 10.1007/978-90-481-2976-8_1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
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162
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Salmand PA, Jungas T, Fernandez M, Conter A, Christians ES. Mouse Heat-Shock Factor 1 (HSF1) Is Involved in Testicular Response to Genotoxic Stress Induced by Doxorubicin1. Biol Reprod 2008; 79:1092-101. [PMID: 18703420 DOI: 10.1095/biolreprod.108.070334] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Affiliation(s)
- Pierre A Salmand
- Université Toulouse 3, Unité Mixte de Recherche 5547 (UMR 5547), Centre National pour la Recherche Scientifique (CNRS)-Université Paul Sabatier (UPS), 31062 Toulouse, France
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163
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McCollum AK, Lukasiewicz KB, TenEyck CJ, Lingle WL, Toft DO, Erlichman C. Cisplatin abrogates the geldanamycin-induced heat shock response. Mol Cancer Ther 2008; 7:3256-64. [PMID: 18852129 PMCID: PMC2572571 DOI: 10.1158/1535-7163.mct-08-0157] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Benzoquinone ansamycin antibiotics such as geldanamycin (GA) bind to the NH(2)-terminal ATP-binding domain of heat shock protein (Hsp) 90 and inhibit its chaperone functions. Despite in vitro and in vivo studies indicating promising antitumor activity, derivatives of GA, including 17-allylaminogeldanamycin (17-AAG), have shown little clinical efficacy as single agents. Thus, combination studies of 17-AAG and several cancer chemotherapeutics, including cisplatin (CDDP), have begun. In colony-forming assays, the combination of CDDP and GA or 17-AAG was synergistic and caused increased apoptosis compared with each agent alone. One measurable response that results from treatment with Hsp90-targeted agents is the induction of a heat shock factor-1 (HSF-1) heat shock response. Treatment with GA + CDDP revealed that CDDP suppresses up-regulation of HSF-1 transcription, causing decreased levels of stress-inducible proteins such as Hsp27 and Hsp70. However, CDDP treatment did not prevent trimerization and nuclear localization of HSF-1 but inhibited DNA binding of HSF-1 as shown by chromatin immunoprecipitation. Melphalan, but not camptothecin, caused similar inhibition of GA-induced HSF-1-mediated Hsp70 up-regulation. 3-(4,5-Dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium salt cell survival assays revealed that deletion of Hsp70 caused increased sensitivity to GA (Hsp70(+/+) IC(50) = 63.7 +/- 14.9 nmol/L and Hsp70(-/-) IC(50) = 4.3 +/- 2.9 nmol/L), which confirmed that a stress response plays a critical role in decreasing GA sensitivity. Our results suggest that the synergy of GA + CDDP is due, in part, to CDDP-mediated abrogation of the heat shock response through inhibition of HSF-1 activity. Clinical modulation of the HSF-1-mediated heat shock response may enhance the efficacy of Hsp90-directed therapy.
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Affiliation(s)
- Andrea K. McCollum
- Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic College of Medicine, Rochester, Minnesota
| | - Kara B. Lukasiewicz
- Tumor Biology Program, Mayo Clinic College of Medicine, Rochester, Minnesota
- Department of Biochemistry and Molecular Biology, Mayo Clinic College of Medicine, Rochester, Minnesota
| | - Cynthia J. TenEyck
- Department of Oncology, Mayo Clinic College of Medicine, Rochester, Minnesota
| | - Wilma L. Lingle
- Tumor Biology Program, Mayo Clinic College of Medicine, Rochester, Minnesota
- Department of Biochemistry and Molecular Biology, Mayo Clinic College of Medicine, Rochester, Minnesota
- Department of Experimental Pathology, Mayo Clinic College of Medicine, Rochester, Minnesota
| | - David O. Toft
- Department of Biochemistry and Molecular Biology, Mayo Clinic College of Medicine, Rochester, Minnesota
| | - Charles Erlichman
- Department of Oncology, Mayo Clinic College of Medicine, Rochester, Minnesota
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164
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DeGracia DJ, Jamison JT, Szymanski JJ, Lewis MK. Translation arrest and ribonomics in post-ischemic brain: layers and layers of players. J Neurochem 2008; 106:2288-301. [PMID: 18627434 PMCID: PMC2574835 DOI: 10.1111/j.1471-4159.2008.05561.x] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
A persistent translation arrest (TA) correlates precisely with the selective vulnerability of post-ischemic neurons. Mechanisms of post-ischemic TA that have been assessed include ribosome biochemistry, the link between TA and stress responses, and the inactivation of translational components via sequestration in subcellular structures. Each of these approaches provides a perspective on post-ischemic TA. Here, we develop the notion that mRNA regulation via RNA-binding proteins, or ribonomics, also contributes to post-ischemic TA. We describe the ribonomic network, or structures involved in mRNA regulation, including nuclear foci, polysomes, stress granules, embryonic lethal abnormal vision/Hu granules, processing bodies, exosomes, and RNA granules. Transcriptional, ribonomic, and ribosomal regulation together provide multiple layers mediating cell reprogramming. Stress gene induction via the heat-shock response, immediate early genes, and endoplasmic reticulum stress represents significant reprogramming of post-ischemic neurons. We present a model of post-ischemic TA in ischemia-resistant neurons that incorporates ribonomic considerations. In this model, selective translation of stress-induced mRNAs contributes to translation recovery. This model provides a basis to study dysfunctional stress responses in vulnerable neurons, with a key focus on the inability of vulnerable neurons to selectively translate stress-induced mRNAs. We suggest a ribonomic approach will shed new light on the roles of mRNA regulation in persistent TA in vulnerable post-ischemic neurons.
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Affiliation(s)
- Donald J DeGracia
- Department of Physiology, Wayne State University, Detroit, Michigan, USA.
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165
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Harrison EM, Sharpe E, Bellamy CO, McNally SJ, Devey L, Garden OJ, Ross JA, Wigmore SJ. Heat shock protein 90-binding agents protect renal cells from oxidative stress and reduce kidney ischemia-reperfusion injury. Am J Physiol Renal Physiol 2008; 295:F397-405. [PMID: 18562631 DOI: 10.1152/ajprenal.00361.2007] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Heat shock proteins (Hsps) are protective in models of transplantation, yet practical strategies to upregulate them remain elusive. The heat shock protein 90-binding agent (HBA) geldanamycin and its analogs (17-AAG and 17-DMAG) are known to upregulate Hsps and confer cellular protection but have not been investigated in a model relevant to transplantation. We examined the ability of HBAs to upregulate Hsp expression and confer protection in renal adenocarcinoma (ACHN) cells in vitro and in a mouse model of kidney ischemia-reperfusion (I/R) injury. Hsp70 gene expression was increased 30-40 times in ACHN cells treated with HBAs, and trimerization and DNA binding of heat shock transcription factor-1 (HSF1) were demonstrated. A three- and twofold increase in Hsp70 and Hsp27 protein expression, respectively, was found in ACHN cells treated with HBAs. HBAs protected ACHN cells from an H2O2-mediated oxidative stress, and HSF1 short interfering RNA was found to abrogate HBA-mediated Hsp induction and protection. In vivo, Hsp70 was upregulated in the kidneys, liver, lungs, and heart of HBA-treated mice. This was associated with a functional and morphological renal protection from I/R injury. Therefore, HBAs mediate upregulation of protective Hsps in mouse kidneys which are associated with reduced I/R injury and may be useful in reducing transplant-associated kidney injury.
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Affiliation(s)
- Ewen M Harrison
- Tissue Injury and Repair Group, University of Edinburgh, Edinburgh, UK.
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166
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Voyer J, Heikkila JJ. Comparison of the effect of heat shock factor inhibitor, KNK437, on heat shock- and chemical stress-induced hsp30 gene expression in Xenopus laevis A6 cells. Comp Biochem Physiol A Mol Integr Physiol 2008; 151:253-61. [PMID: 18675372 DOI: 10.1016/j.cbpa.2008.07.004] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2008] [Revised: 07/03/2008] [Accepted: 07/07/2008] [Indexed: 11/24/2022]
Abstract
In this study, we compared the effect of KNK437 (N-formyl-3, 4-methylenedioxy-benzylidene-gamma-butyrolactam), a benzylidene lactam compound, on heat shock and chemical stressor-induced hsp30 gene expression in Xenopus laevis A6 kidney epithelial cells. Previously, KNK437 was shown to inhibit HSE-HSF1 binding activity and heat-induced hsp gene expression. In the present study, Northern and Western blot analysis revealed that pretreatment of A6 cells with KNK437 inhibited hsp30 mRNA and HSP30 and HSP70 protein accumulation induced by chemical stressors including sodium arsenite, cadmium chloride and herbimycin A. In A6 cells subjected to sodium arsenite, cadmium chloride, herbimycin A or a 33 degrees C heat shock treatment, immunocytochemistry and confocal microscopy revealed that HSP30 accumulated primarily in the cytoplasm. However, incubation of A6 cells at 35 degrees C resulted in enhanced HSP30 accumulation in the nucleus. Pre-treatment with 100 microM KNK437 completely inhibited HSP30 accumulation in A6 cells heat shocked at 33 or 35 degrees C as well as cells treated with 10 microM sodium arsenite, 100 microM cadmium chloride or 1 microg/mL herbimycin A. These results show that KNK437 is effective at inhibiting both heat shock- and chemical stress-induced hsp gene expression in amphibian cells.
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Affiliation(s)
- Janine Voyer
- Department of Biology, University of Waterloo, Waterloo, ON, N2L 3G1, Canada
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167
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Yeyati PL, van Heyningen V. Incapacitating the evolutionary capacitor: Hsp90 modulation of disease. Curr Opin Genet Dev 2008; 18:264-72. [PMID: 18662780 DOI: 10.1016/j.gde.2008.07.004] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2008] [Accepted: 07/02/2008] [Indexed: 11/24/2022]
Abstract
The nature-nurture argument surrounding the mechanisms of disease causation cannot be resolved, as the roles of genes and environment are inextricably entwined. Environmental fluctuation is clearly a major modifier of phenotype, as well as a promoter of evolutionary change. Both types of variability can be mediated by the stress response pathway, with the Hsp90 chaperone family as key components. Hsp90 has been hailed as a capacitor for evolutionary change, because partial inhibition of its functions can uncover cryptic mutations, leading to unexpected phenotypes that, although generally deleterious, will under rare new environmental conditions provide improved survival to the carrier of that variant. There is, therefore, a strong environmentally elicited link between the capacity to reveal hidden variation as human disease phenotype and as novel morphological forms for evolutionary selection.
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Affiliation(s)
- Patricia L Yeyati
- Medical Research Council Human Genetics Unit, Western General Hospital, Crewe Road, Edinburgh, UK.
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168
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Chan CC, Zhang S, Rousset R, Wharton KA. Drosophila Naked cuticle (Nkd) engages the nuclear import adaptor Importin-alpha3 to antagonize Wnt/beta-catenin signaling. Dev Biol 2008; 318:17-28. [PMID: 18423435 PMCID: PMC2585751 DOI: 10.1016/j.ydbio.2008.02.050] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2007] [Revised: 02/06/2008] [Accepted: 02/07/2008] [Indexed: 01/08/2023]
Abstract
Precise control of Wnt/beta-catenin signaling is critical for animal development, stem cell renewal, and prevention of disease. In the fruit fly Drosophila melanogaster, the naked cuticle (nkd) gene limits signaling by the Wnt ligand Wingless (Wg) during embryo segmentation. Nkd is an intracellular protein that is composed of separable membrane- and nuclear-localization sequences (NLS) as well as a conserved EF-hand motif that binds the Wnt receptor-associated scaffold protein Dishevelled (Dsh), but the mechanism by which Nkd inhibits Wnt signaling remains a mystery. Here we identify a second NLS in Nkd that is required for full activity and that binds to the canonical nuclear import adaptor Importin-alpha3. The Nkd NLS is similar to the Importin-alpha3-binding NLS in the Drosophila heat-shock transcription factor (dHSF), and each Importin-alpha3-binding NLS required intact basic residues in similar positions for nuclear import and protein function. Our results provide further support for the hypothesis that Nkd inhibits nuclear step(s) in Wnt/beta-catenin signaling and broaden our understanding of signaling pathways that engage the nuclear import machinery.
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Affiliation(s)
- Chih-Chiang Chan
- Laboratory of Molecular Pathology, Departments of Pathology, UT Southwestern Medical Center, Dallas, TX 75390-9072, USA
| | - Shu Zhang
- Laboratory of Molecular Pathology, Departments of Pathology, UT Southwestern Medical Center, Dallas, TX 75390-9072, USA
| | - Raphaël Rousset
- Department of Developmental Biology, Howard Hughes Medical Institute, Stanford University, Stanford, CA 94305, USA
| | - Keith A. Wharton
- Laboratory of Molecular Pathology, Departments of Pathology, UT Southwestern Medical Center, Dallas, TX 75390-9072, USA
- Molecular Biology, UT Southwestern Medical Center, Dallas, TX 75390-9072, USA
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169
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Lu M, Kim HE, Li CR, Kim S, Kwak IJ, Lee YJ, Kim SS, Moon JY, Kim CH, Kim DK, Kang HS, Park JS. Two Distinct Disulfide Bonds Formed in Human Heat Shock Transcription Factor 1 Act in Opposition To Regulate Its DNA Binding Activity. Biochemistry 2008; 47:6007-15. [DOI: 10.1021/bi702185u] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Affiliation(s)
- Ming Lu
- Department of Chemistry and Center for Innovative Bio·Physio Sensor Technology and Department of Molecular Biology, Pusan National University, 609-735 Busan, South Korea, and Department of Biomedicinal Chemistry and Institute of Functional Materials, Inje University, 621-749 Kimhae, South Korea
| | - Hee-Eun Kim
- Department of Chemistry and Center for Innovative Bio·Physio Sensor Technology and Department of Molecular Biology, Pusan National University, 609-735 Busan, South Korea, and Department of Biomedicinal Chemistry and Institute of Functional Materials, Inje University, 621-749 Kimhae, South Korea
| | - Chun-Ri Li
- Department of Chemistry and Center for Innovative Bio·Physio Sensor Technology and Department of Molecular Biology, Pusan National University, 609-735 Busan, South Korea, and Department of Biomedicinal Chemistry and Institute of Functional Materials, Inje University, 621-749 Kimhae, South Korea
| | - Sol Kim
- Department of Chemistry and Center for Innovative Bio·Physio Sensor Technology and Department of Molecular Biology, Pusan National University, 609-735 Busan, South Korea, and Department of Biomedicinal Chemistry and Institute of Functional Materials, Inje University, 621-749 Kimhae, South Korea
| | - Im-Jung Kwak
- Department of Chemistry and Center for Innovative Bio·Physio Sensor Technology and Department of Molecular Biology, Pusan National University, 609-735 Busan, South Korea, and Department of Biomedicinal Chemistry and Institute of Functional Materials, Inje University, 621-749 Kimhae, South Korea
| | - Yun-Ju Lee
- Department of Chemistry and Center for Innovative Bio·Physio Sensor Technology and Department of Molecular Biology, Pusan National University, 609-735 Busan, South Korea, and Department of Biomedicinal Chemistry and Institute of Functional Materials, Inje University, 621-749 Kimhae, South Korea
| | - So-Sun Kim
- Department of Chemistry and Center for Innovative Bio·Physio Sensor Technology and Department of Molecular Biology, Pusan National University, 609-735 Busan, South Korea, and Department of Biomedicinal Chemistry and Institute of Functional Materials, Inje University, 621-749 Kimhae, South Korea
| | - Ji-Young Moon
- Department of Chemistry and Center for Innovative Bio·Physio Sensor Technology and Department of Molecular Biology, Pusan National University, 609-735 Busan, South Korea, and Department of Biomedicinal Chemistry and Institute of Functional Materials, Inje University, 621-749 Kimhae, South Korea
| | - Cho Hee Kim
- Department of Chemistry and Center for Innovative Bio·Physio Sensor Technology and Department of Molecular Biology, Pusan National University, 609-735 Busan, South Korea, and Department of Biomedicinal Chemistry and Institute of Functional Materials, Inje University, 621-749 Kimhae, South Korea
| | - Dong-Kyoo Kim
- Department of Chemistry and Center for Innovative Bio·Physio Sensor Technology and Department of Molecular Biology, Pusan National University, 609-735 Busan, South Korea, and Department of Biomedicinal Chemistry and Institute of Functional Materials, Inje University, 621-749 Kimhae, South Korea
| | - Ho Sung Kang
- Department of Chemistry and Center for Innovative Bio·Physio Sensor Technology and Department of Molecular Biology, Pusan National University, 609-735 Busan, South Korea, and Department of Biomedicinal Chemistry and Institute of Functional Materials, Inje University, 621-749 Kimhae, South Korea
| | - Jang-Su Park
- Department of Chemistry and Center for Innovative Bio·Physio Sensor Technology and Department of Molecular Biology, Pusan National University, 609-735 Busan, South Korea, and Department of Biomedicinal Chemistry and Institute of Functional Materials, Inje University, 621-749 Kimhae, South Korea
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170
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Putics Á, Vödrös D, Malavolta M, Mocchegiani E, Csermely P, Sőti C. Zinc supplementation boosts the stress response in the elderly: Hsp70 status is linked to zinc availability in peripheral lymphocytes. Exp Gerontol 2008; 43:452-61. [DOI: 10.1016/j.exger.2008.01.002] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2007] [Revised: 12/07/2007] [Accepted: 01/08/2008] [Indexed: 12/23/2022]
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171
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Bettencourt BR, Hogan CC, Nimali M, Drohan BW. Inducible and constitutive heat shock gene expression responds to modification of Hsp70 copy number in Drosophila melanogaster but does not compensate for loss of thermotolerance in Hsp70 null flies. BMC Biol 2008; 6:5. [PMID: 18211703 PMCID: PMC2257928 DOI: 10.1186/1741-7007-6-5] [Citation(s) in RCA: 86] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2007] [Accepted: 01/22/2008] [Indexed: 06/12/2024] Open
Abstract
Background The heat shock protein Hsp70 promotes inducible thermotolerance in nearly every organism examined to date. Hsp70 interacts with a network of other stress-response proteins, and dissecting the relative roles of these interactions in causing thermotolerance remains difficult. Here we examine the effect of Hsp70 gene copy number modification on thermotolerance and the expression of multiple stress-response genes in Drosophila melanogaster, to determine which genes may represent mechanisms of stress tolerance independent of Hsp70. Results Hsp70 copy number in four strains is positively associated with Hsp70 expression and inducible thermotolerance of severe heat shock. When assayed at carefully chosen temperatures, Hsp70 null flies are almost entirely deficient in thermotolerance. In contrast to expectations, increasing Hsp70 expression levels induced by thermal pretreatment are associated with increasing levels of seven other inducible Hsps across strains. In addition, complete Hsp70 loss causes upregulation of the inducible Hsps and six constitutive stress-response genes following severe heat shocks. Conclusion Modification of Hsp70 copy number quantitatively and qualitatively affects the expression of multiple other stress-response genes. A positive association between absolute expression levels of Hsp70 and other Hsps after thermal pretreatment suggests novel regulatory mechanisms. Severe heat shocks induce both novel gene expression patterns and almost total mortality in the Hsp70 null strain: alteration of gene expression in this strain does not compensate for Hsp70 loss but suggests candidates for overexpression studies.
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Affiliation(s)
- Brian R Bettencourt
- Department of Biological Sciences, University of Massachusetts Lowell, 1 University Avenue, Lowell, MA 01854, USA.
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172
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Boyault C, Khochbin S. [HDAC6 orchestrates cell defense responses against cytotoxic protein aggregates]. Med Sci (Paris) 2008; 24:15-7. [PMID: 18198099 DOI: 10.1051/medsci/200824115] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Cyril Boyault
- INSERM U823, Equipe épigénétique et signalisation cellulaire, Institut Albert Bonniot, Rond-point de la Chantourne, La Tronche Cedex Grenoble, France.
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173
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Putics A, Végh EM, Csermely P, Soti C. Resveratrol induces the heat-shock response and protects human cells from severe heat stress. Antioxid Redox Signal 2008; 10:65-75. [PMID: 17956190 DOI: 10.1089/ars.2007.1866] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Molecular chaperones play key roles in protein quality control, signal transduction, proliferation, and cell death, and confer cytoprotection and assure survival after environmental stress. The heat-shock response is implicated in a variety of conditions including ischemic diseases, infection and immunity, neurodegeneration, and aging. Physiologic and pharmacologic chaperone inducers were shown to be an efficient therapeutic approach in different acute and chronic diseases. Here we characterize resveratrol, a polyphenol from red wine, as an inducer of the heat-shock response. Resveratrol activated the heat-shock promoter and the expression of the major chaperone Hsp70 in cell lines and in human peripheral lymphocytes, comparable to moderate heat stress. This effect was not due to its antioxidant property, because 5 mM N-acetylcysteine was unable to activate the heat-shock response. Moreover, resveratrol failed to upregulate Grp78, and tunicamycin was unable to induce Hsp70, suggesting that the resveratrol-induced heat-shock response was not mediated by canonic endoplasmic reticulum stress. Resveratrol synergized with mild to moderate heat shock and conferred cytoprotection against severe heat stress. Our results reveal resveratrol as a chaperone inducer that may contribute to its pleiotropic effects in ameliorating stress and promoting longevity.
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Affiliation(s)
- Akos Putics
- Department of Medical Chemistry, Semmelweis University, Budapest, Hungary
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174
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Different requirements of the SWI/SNF complex for robust nucleosome displacement at promoters of heat shock factor and Msn2- and Msn4-regulated heat shock genes. Mol Cell Biol 2007; 28:1207-17. [PMID: 18070923 DOI: 10.1128/mcb.01069-07] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The stress response in yeast cells is regulated by at least two classes of transcription activators-HSF and Msn2/4, which differentially affect promoter chromatin remodeling. We demonstrate that the deletion of SNF2, an ATPase activity-containing subunit of the chromatin remodeling SWI/SNF complex, eliminates histone displacement, RNA polymerase II recruitment, and heat shock factor (HSF) binding at the HSP12 promoter while delaying these processes at the HSP82 and SSA4 promoters. Out of the three promoters, the double deletion of MSN2 and MSN4 eliminates both chromatin remodeling and HSF binding only at the HSP12 promoter, suggesting that Msn2/4 activators are primary determinants of chromatin disassembly at the HSP12 promoter. Unexpectedly, during heat shock the level of Msn2/4 at the HSP12 promoter declines. This is likely a result of promoter-targeted Msn2/4 degradation associated with transcription complex assembly. While histone displacement kinetic profiles bear clear promoter specificity, the kinetic profiles of recovery from heat shock for all analyzed genes display an equal or even higher nucleosome return rate, which is to some extent delayed by the deletion of SNF2.
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175
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Zhang YQ, Sarge KD. Celastrol inhibits polyglutamine aggregation and toxicity though induction of the heat shock response. J Mol Med (Berl) 2007; 85:1421-8. [PMID: 17943263 PMCID: PMC2262918 DOI: 10.1007/s00109-007-0251-9] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2006] [Revised: 07/06/2007] [Accepted: 07/19/2007] [Indexed: 11/27/2022]
Abstract
Heat shock proteins (hsps) are protective against the harmful effects of mutant expanded polyglutamine repeat proteins that occur in diseases such as Huntington's, prompting the search for pharmacologic compounds that increase hsp expression in cells as potential treatments for this and related diseases. In this paper, we show that celastrol, a compound recently shown to up-regulate hsp gene expression, significantly decreases killing of cells expressing mutant polyglutamine protein. This effect requires the presence of the transcription factor responsible for mediating inducible hsp gene expression, HSF1, and is correlated with decreased amounts and increased sodium dodecyl sulfate (SDS) solubility of polyglutamine aggregates. These results suggest the potential of celastrol as a therapeutic agent in the treatment of human polyglutamine expansion diseases.
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Affiliation(s)
- Yu-Qian Zhang
- Department of Molecular and Cellular Biochemistry, University of Kentucky, 741 S. Limestone Street, Lexington, KY 40536 USA
| | - Kevin D. Sarge
- Department of Molecular and Cellular Biochemistry, University of Kentucky, 741 S. Limestone Street, Lexington, KY 40536 USA
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176
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Skaggs HS, Xing H, Wilkerson DC, Murphy LA, Hong Y, Mayhew CN, Sarge KD. HSF1-TPR interaction facilitates export of stress-induced HSP70 mRNA. J Biol Chem 2007; 282:33902-7. [PMID: 17897941 PMCID: PMC2266631 DOI: 10.1074/jbc.m704054200] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Stress conditions inhibit mRNA export, but mRNAs encoding heat shock proteins continue to be efficiently exported from the nucleus during stress. How HSP mRNAs bypass this stress-associated export inhibition was not known. Here, we show that HSF1, the transcription factor that binds HSP promoters after stress to induce their transcription, interacts with the nuclear pore-associating TPR protein in a stress-responsive manner. TPR is brought into proximity of the HSP70 promoter after stress and preferentially associates with mRNAs transcribed from this promoter. Disruption of the HSF1-TPR interaction inhibits the export of mRNAs expressed from the HSP70 promoter, both endogenous HSP70 mRNA and a luciferase reporter mRNA. These results suggest that HSP mRNA export escapes stress inhibition via HSF1-mediated recruitment of the nuclear pore-associating protein TPR to HSP genes, thereby functionally connecting the first and last nuclear steps of the gene expression pathway, transcription and mRNA export.
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Affiliation(s)
- Hollie S Skaggs
- Department of Molecular and Cellular Biochemistry, Chandler Medical Center, University of Kentucky, 741 S. Limestone Street, Lexington, KY 40536-0084, USA
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177
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Schulz-Raffelt M, Lodha M, Schroda M. Heat shock factor 1 is a key regulator of the stress response in Chlamydomonas. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2007; 52:286-95. [PMID: 17711413 DOI: 10.1111/j.1365-313x.2007.03228.x] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
We report here on the characterization of heat shock factor 1 (HSF1), encoded by one of two HSF genes identified in the genome of Chlamydomonas reinhardtii. Chlamydomonas HSF1 shares features characteristic of class A HSFs of higher plants. HSF1 is weakly expressed under non-stress conditions and rapidly induced by heat shock. Heat shock also resulted in hyperphosphorylation of HSF1, and the extent of phosphorylation correlated with the degree of induction of heat shock genes, suggesting a role for phosphorylation in HSF1 activation. HSF1, like HSFs in yeasts, forms high-molecular-weight complexes, presumably trimers, under non-stress, stress and recovery conditions. Immunoprecipitation of HSF1 under these conditions led to the identification of cytosolic HSP70A as a protein constitutively interacting with HSF1. Strains in which HSF1 was strongly under-expressed by RNAi were highly sensitive to heat stress. 14C-labelling of nuclear-encoded proteins under heat stress revealed that synthesis of members of the HSP100, HSP90, HSP70, HSP60 and small HSP families in the HSF1-RNAi strains was dramatically reduced or completely abolished. This correlated with a complete loss of HSP gene induction at the RNA level. These data suggest that HSF1 is a key regulator of the stress response in Chlamydomonas.
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Affiliation(s)
- Miriam Schulz-Raffelt
- Institute of Biology II, University of Freiburg, Schänzlestr. 1, D-79104 Freiburg, Germany
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178
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von Koskull-Döring P, Scharf KD, Nover L. The diversity of plant heat stress transcription factors. TRENDS IN PLANT SCIENCE 2007; 12:452-7. [PMID: 17826296 DOI: 10.1016/j.tplants.2007.08.014] [Citation(s) in RCA: 329] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/02/2007] [Revised: 07/13/2007] [Accepted: 08/29/2007] [Indexed: 05/17/2023]
Abstract
Compared with other eukaryotes with one to three heat stress transcription factors (Hsf), the plant Hsf family shows a striking multiplicity, with more than 20 members. Despite many conserved features, members of the Hsf family show a strong diversification of expression pattern and function within the family. Research on Arabidopsis Hsfs opened a new era with genome-wide transcriptome profiling in combination with the availability of knockout lines. The output from these analyses provides increasing evidence that individual Hsfs have unique functions as part of different signal transduction pathways operating in response to environmental stress and during development.
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Affiliation(s)
- Pascal von Koskull-Döring
- Department of Molecular Cell Biology, J. W. Goethe University, Biocenter, Max-von-Laue-Str. 9, D-60438 Frankfurt am Main, Germany.
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179
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Two Functional Domains of Human Heat Shock Factor 1 Have Different Effects on Its DNA-binding Activity through Redox Changes. B KOREAN CHEM SOC 2007. [DOI: 10.5012/bkcs.2007.28.9.1455] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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180
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Boyault C, Zhang Y, Fritah S, Caron C, Gilquin B, Kwon SH, Garrido C, Yao TP, Vourc’h C, Matthias P, Khochbin S. HDAC6 controls major cell response pathways to cytotoxic accumulation of protein aggregates. Genes Dev 2007; 21:2172-81. [PMID: 17785525 PMCID: PMC1950856 DOI: 10.1101/gad.436407] [Citation(s) in RCA: 298] [Impact Index Per Article: 16.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2007] [Accepted: 07/13/2007] [Indexed: 11/24/2022]
Abstract
A cellular defense mechanism counteracts the deleterious effects of misfolded protein accumulation by eliciting a stress response. The cytoplasmic deacetylase HDAC6 (histone deacetylase 6) was previously shown to be a key element in this response by coordinating the clearance of protein aggregates through aggresome formation and their autophagic degradation. Here, for the first time, we demonstrate that HDAC6 is involved in another crucial cell response to the accumulation of ubiquitinated protein aggregates, and unravel its molecular basis. Indeed, our data show that HDAC6 senses ubiquitinated cellular aggregates and consequently induces the expression of major cellular chaperones by triggering the dissociation of a repressive HDAC6/HSF1 (heat-shock factor 1)/HSP90 (heat-shock protein 90) complex and a subsequent HSF1 activation. HDAC6 therefore appears as a master regulator of the cell protective response to cytotoxic protein aggregate formation.
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Affiliation(s)
- Cyril Boyault
- Institut National de la Santé et de la Recherche Médicale (INSERM), U823, Institut Albert Bonniot, Grenoble F-38706, France
- Université Joseph Fourier, Institut Albert Bonniot, Grenoble F-38700, France
| | - Yu Zhang
- Friedrich Miescher Institute for Biomedical Research, Novartis Research Foundation, 4058 Basel, Switzerland
| | - Sabrina Fritah
- Institut National de la Santé et de la Recherche Médicale (INSERM), U823, Institut Albert Bonniot, Grenoble F-38706, France
- Université Joseph Fourier, Institut Albert Bonniot, Grenoble F-38700, France
| | - Cécile Caron
- Institut National de la Santé et de la Recherche Médicale (INSERM), U823, Institut Albert Bonniot, Grenoble F-38706, France
- Université Joseph Fourier, Institut Albert Bonniot, Grenoble F-38700, France
| | - Benoit Gilquin
- Institut National de la Santé et de la Recherche Médicale (INSERM), U823, Institut Albert Bonniot, Grenoble F-38706, France
- Université Joseph Fourier, Institut Albert Bonniot, Grenoble F-38700, France
| | - So Hee Kwon
- Friedrich Miescher Institute for Biomedical Research, Novartis Research Foundation, 4058 Basel, Switzerland
| | - Carmen Garrido
- INSERM, U517, Dijon F-21079, France
- Université de Bourgogne, Faculté de Médecine de Dijon, Dijon F-21079, France
| | - Tso-Pang Yao
- Department of Pharmacology and Cancer Biology, Duke University, Durham, North Carolina 27710, USA
| | - Claire Vourc’h
- Institut National de la Santé et de la Recherche Médicale (INSERM), U823, Institut Albert Bonniot, Grenoble F-38706, France
- Université Joseph Fourier, Institut Albert Bonniot, Grenoble F-38700, France
| | - Patrick Matthias
- Friedrich Miescher Institute for Biomedical Research, Novartis Research Foundation, 4058 Basel, Switzerland
| | - Saadi Khochbin
- Institut National de la Santé et de la Recherche Médicale (INSERM), U823, Institut Albert Bonniot, Grenoble F-38706, France
- Université Joseph Fourier, Institut Albert Bonniot, Grenoble F-38700, France
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181
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Taylor DM, Tradewell ML, Minotti S, Durham HD. Characterizing the role of Hsp90 in production of heat shock proteins in motor neurons reveals a suppressive effect of wild-type Hsf1. Cell Stress Chaperones 2007; 12:151-62. [PMID: 17688194 PMCID: PMC1949336 DOI: 10.1379/csc-254r.1] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Induction of heat shock proteins (Hsps) is under investigation as treatment for neurodegenerative disorders, yet many types of neurons, including motor neurons that degenerate in amyotrophic lateral sclerosis (ALS), have a high threshold for activation of the major transcription factor mediating stress-induced Hsp upregulation, heat shock transcription factor 1 (Hsf1). Hsf1 is tightly regulated by a series of inhibitory checkpoints that include sequestration in multichaperone complexes governed by Hsp90. This study examined the role of multichaperone complexes in governing the heat shock response in motor neurons. Hsp90 inhibitors induced expression of Hsp70 and Hsp40 and transactivation of a human inducible hsp70 promoter-green fluorescent protein (GFP) reporter construct in motor neurons of dissociated spinal cord-dorsal root ganglion (DRG) cultures. On the other hand, overexpression of activator of Hsp90 adenosine triphosphatase ([ATPase 1], Aha1), which should mobilize Hsf1 by accelerating turnover of mature, adenosine triphosphate-(ATP) bound Hsp90 complexes, and death domain-associated protein (Daxx), which in cell lines has been shown to promote transcription of heat shock genes by relieving inhibition exerted by interactions between nuclear Hsp90/multichaperone complexes and trimeric Hsf1, failed to induce Hsps in the absence or presence of heat shock. These results indicate that disruption of multichaperone complexes alone is not sufficient to activate the neuronal heat shock response. Furthermore, in motor neurons, induction of Hsp70 by Hsp90-inhibiting drugs was prevented by overexpression of wild-type Hsfl, contrary to what would be expected for a classical Hsf1-mediated pathway. These results point to additional differences in regulation of hsp genes in neuronal and nonneuronal cells.
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Affiliation(s)
- David M Taylor
- Montreal Neurological Institute, McGill University, 3801 University St., Montreal, Quebec H3A 2B4, Canada
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182
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Xing H, Hong Y, Sarge KD. Identification of the PP2A-interacting region of heat shock transcription factor 2. Cell Stress Chaperones 2007; 12:192-7. [PMID: 17688198 PMCID: PMC1949333 DOI: 10.1379/csc-249r.1] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
Previous work in our laboratory demonstrated the existence of an association between heat shock transcription factor 2 (HSF2) and the serine/threonine phosphatase 2A, which is mediated by interaction between HSF2 and the A subunit (also called PR65) of this protein phosphatase. In light of the importance of HSF2-PP2A association for HSF2 cellular function, in this study, we have sought to dissect the sequences within HSF2 that are important for interaction with the A subunit of PP2A. The results of these experiments indicate that the HSF2 region comprising amino acids 343-363 is important for A subunit interaction. This region includes part of the C-terminal leucine zipper motif of HSF2 called heptad repeat C (HR-C). The results of transfection/immunoprecipitation experiments also show that deletion of the 6 amino acids from 343 to 348 from HSF2 (HSF2 (delta343-348)), is sufficient to prevent HSF2 from interacting with PP2A. These data provide insight into a new functional domain of HSF2, the PP2A A subunit-interacting region.
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Affiliation(s)
- Hongyan Xing
- Department of Molecular and Cellular Biochemistry, University of Kentucky, 741 S Limestone Streeet, Lexington, KY 40536, USA
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183
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Nadeau SI, Landry J. Mechanisms of Activation and Regulation of the Heat Shock-Sensitive Signaling Pathways. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2007; 594:100-13. [PMID: 17205679 DOI: 10.1007/978-0-387-39975-1_10] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Heat shock (HS), like many other stresses, induces specific and highly regulated signaling cascades that promote cellular homeostasis. The three major mitogen-activated protein kinases (MAPK) and protein kinase B (PKB/Akt) are the most notable of these HS-stimulated pathways. Their activation occurs rapidly and sooner than the transcriptional upregulation of heat shock proteins (Hsp), which generate a transient state of extreme resistance against subsequent thermal stress. The direct connection of these signaling pathways to cellular death or survival mechanisms suggests that they contribute importantly to the HS response. Some of them may counteract early noxious effects of heat, while others may bolster key apoptosis events. The triggering events responsible for activating these pathways are unclear. Protein denaturation, specific and nonspecific receptor activation, membrane alteration and chromatin structure perturbation are potential initiating factors.
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Affiliation(s)
- Sébastien Ian Nadeau
- Centre de recherche en cancérologie de I'Université Laval, L'Hôtel-Dieu de Québec, 9, rue McMahon, Québec, Canada G1 R 2J6
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184
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Huen NYM, Wong SLA, Chan HYE. Transcriptional malfunctioning of heat shock protein gene expression in spinocerebellar ataxias. THE CEREBELLUM 2007; 6:111-7. [PMID: 17510910 DOI: 10.1080/14734220600996480] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Among the various dominantly-inherited spinocerebellar ataxias (SCAs), at least seven of them belong to the polyglutamine disease group and are caused by glutamine-coding CAG triplet repeat expansion. The expanded coding CAG repeat translates into a polyglutamine stretch in the disease protein, which leads to late-onset and progressive neurodegeneration. Expanded polyglutamine adopts a misfolded protein conformation, and is itself a cellular stressor which induces robust heat shock response (HSR). Under polyglutamine stress, heat shock proteins (Hsps) are produced in neurons to assist refolding and/or promote the degradation of misfolded proteins. Along with the progressive nature of polyglutamine degeneration, a gradual decline of HSR in degenerating neurons was observed. Such kind of reduction can be observed in a large family of hsp gene expression, including hsp22, 26, 27, and 70. This underscores an intimate relationship between the inducibility of hsp gene expression and the disease progression. In this review, we describe the current understandings of hsp gene dysregulation in polyglutamine disease.
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Affiliation(s)
- N Y Macy Huen
- Laboratory of Drosophila Research, Chinese University of Hong Kong, Hong Kong, China
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185
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Manwell LA, Heikkila JJ. Examination of KNK437- and quercetin-mediated inhibition of heat shock-induced heat shock protein gene expression in Xenopus laevis cultured cells. Comp Biochem Physiol A Mol Integr Physiol 2007; 148:521-30. [PMID: 17681842 DOI: 10.1016/j.cbpa.2007.06.422] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2007] [Revised: 06/28/2007] [Accepted: 06/28/2007] [Indexed: 11/28/2022]
Abstract
We examined the effect of quercetin (3,3',4',5,7-pentahydroxyflavon) and KNK437 (N-formyl-3,4-methylenedioxy-benzylidene-gamma-butyrolactam), a benzylidene lactam compound, on heat-induced heat shock protein (hsp) gene expression in Xenopus laevis A6 kidney epithelial cells. In previous studies, both quercetin and KNK437 inhibited heat shock factor activity resulting in a repression of hsp mRNA and protein accumulation in human cultured cells. In this first study of the effect of these hsp gene expression inhibitors in a non-mammalian cell line, we report that both quercetin and KNK437 reduced the heat shock-induced accumulation of hsp30, hsp47 and hsp70 mRNA in X. laevis cultured cells. However, these inhibitors had no effect on the relative level of a non-heat shock protein mRNA, ef1alpha, in either control or heat shocked cells. Western blot and immunocytochemical analyses revealed that quercetin partially inhibited HSP30 protein accumulation. In contrast, HSP30 protein was not detectable in KNK437-treated cells. Finally, treatment of A6 cells with KNK437 inhibited the heat shock-induced acquisition of thermotolerance, as determined by preservation of actin filaments and cellular morphology using immunocytochemistry and laser scanning confocal microscopy.
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Affiliation(s)
- Laurie A Manwell
- Department of Biology, University of Waterloo, Waterloo, ON, Canada N2L 3G1
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186
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Heikkila JJ, Kaldis A, Morrow G, Tanguay RM. The use of the Xenopus oocyte as a model system to analyze the expression and function of eukaryotic heat shock proteins. Biotechnol Adv 2007; 25:385-95. [PMID: 17459646 DOI: 10.1016/j.biotechadv.2007.03.003] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2007] [Revised: 03/21/2007] [Accepted: 03/21/2007] [Indexed: 11/26/2022]
Abstract
The analysis of the expression and function of heat shock protein (hsp) genes, a class of molecular chaperones, has been greatly aided by studies carried out with Xenopus oocytes. The large size of the oocyte facilitates microinjection of DNA, mRNA or protein, permits manual dissection of nuclei, and allows certain assays to be performed with single oocytes. These and other characteristics were useful in identifying the cis- and trans-acting factors involved in hsp gene transcription as well as the role of chaperones and co-chaperones in the repression and activation of heat shock factor. Xenopus oocytes were used to examine heat shock protein (HSP) molecular chaperone function as well as their involvement in intracellular trafficking, maturation, and secretion of protein. Possible new areas of research with this system include the role of membranes in the heat shock response, involvement of HSPs in viral replication and maturation, and in vivo NMR spectroscopy of microinjected HSPs.
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Affiliation(s)
- John J Heikkila
- Department of Biology, University of Waterloo, Waterloo, ON, Canada N2L 3G1.
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187
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Yamamoto A, Ueda J, Yamamoto N, Hashikawa N, Sakurai H. Role of heat shock transcription factor in Saccharomyces cerevisiae oxidative stress response. EUKARYOTIC CELL 2007; 6:1373-9. [PMID: 17586717 PMCID: PMC1951129 DOI: 10.1128/ec.00098-07] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The heat shock transcription factor Hsf1 of the yeast Saccharomyces cerevisiae regulates the transcription of a set of genes that contain heat shock elements (HSEs) in their promoters and function in diverse cellular processes, including protein folding. Here, we show that Hsf1 activates the transcription of various target genes when cells are treated with oxidizing reagents, including the superoxide anion generators menadione and KO(2) and the thiol oxidants diamide and 1-chloro-2,4-dinitrobenzene (CDNB). Similar to heat shock, the oxidizing reagents are potent inducers of both efficient HSE binding and extensive phosphorylation of Hsf1. The inducible phosphorylation of Hsf1 is regulated by the intramolecular domain-domain interactions and affects HSE structure-specific transcription. Unlike the heat shock, diamide, or CDNB response, menadione or KO(2) activation of Hsf1 is inhibited by cyclic-AMP-dependent protein kinase (PKA) activity, which negatively regulates the activator functions of other transcriptional regulators implicated in the oxidative stress response. These results demonstrate that Hsf1 is a member of the oxidative stress-responsive activators and that PKA is a general negative regulator in the superoxide anion response.
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Affiliation(s)
- Ayako Yamamoto
- Division of Health Sciences, Graduate School of Medical Science, Kanazawa University, 5-11-80 Kodatsuno, Kanazawa, Ishikawa 920-0942, Japan
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188
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Abstract
Irreversible translation arrest occurs in reperfused neurons that will die by delayed neuronal death. It is now recognized that suppression of protein synthesis is a general response of eukaryotic cells to exogenous stressors. Indeed, stress-induced translation arrest can be viewed as a component of cell stress responses, and consists of initiation, maintenance, and termination phases that work in concert with stress-induced transcriptional mechanisms. Within this framework, we review translation arrest in reperfused neurons. This framework provides a basis to recognize that phosphorylation of the alpha subunit of eukaryotic initiation factor 2 is the initiator of translation arrest, and a key marker indicating activation of neuronal stress responses. However, eIF2 alpha phosphorylation is reversible. Other phases of stress-induced translation arrest appear to contribute to irreversible translation arrest specifically in ischemic vulnerable neuron populations. We detail two lines of evidence supporting this view. First, ischemia, as a stress stimulus, induces irreversible co-translational protein misfolding and aggregation after 4 to 6 h of reperfusion, trapping protein synthesis machinery into functionally inactive protein aggregates. Second, ischemia and reperfusion leads to modifications of stress granules (SGs) that sequester functionally inactive 48S preinitiation complexes to maintain translation arrest. At later reperfusion durations, these mechanisms may converge such that SGs become sequestered in protein aggregates. These mechanisms result in elimination of functionally active ribosomes and preclude recovery of protein synthesis in selectively vulnerable neurons. Thus, recognizing translation arrest as a component of endogenous cellular stress response pathways will aid in making sense of the complexities of postischemic translation arrest.
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Affiliation(s)
- Donald J DeGracia
- Department of Physiology and the Center for Molecular Medicine and Genetics, Wayne State University, Detroit, Michigan 48201, USA.
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189
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Hashikawa N, Yamamoto N, Sakurai H. Different Mechanisms Are Involved in the Transcriptional Activation by Yeast Heat Shock Transcription Factor through Two Different Types of Heat Shock Elements. J Biol Chem 2007; 282:10333-40. [PMID: 17289668 DOI: 10.1074/jbc.m609708200] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The hydrophobic repeat is a conserved structural motif of eukaryotic heat shock transcription factor (HSF) that enables HSF to form a homotrimer. Homotrimeric HSF binds to heat shock elements (HSEs) consisting of three inverted repeats of the sequence nGAAn. Sequences consisting of four or more nGAAn units are bound cooperatively by two HSF trimers. We show that in Saccharomyces cerevisiae cells oligomerization-defective Hsf1 is not able to bind HSEs with three units and is not extensively phosphorylated in response to stress; it is therefore unable to activate genes containing this type of HSE. Several lines of evidence indicate that oligomerization is a prerequisite for stress-induced hyperphosphorylation of Hsf1. In contrast, oligomerization and hyperphosphorylation are not necessary for gene activation via HSEs with four units. Intragenic suppressor screening of oligomerization-defective hsf1 showed that an interface between adjacent DNA-binding domains is important for the binding of Hsf1 to the HSE. We suggest that Saccharomyces cerevisiae HSEs with different structures are regulated differently; HSEs with three units require Hsf1 to be both oligomerized and hyperphosphorylated, whereas HSEs with four or more units do not require either.
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Affiliation(s)
- Naoya Hashikawa
- Division of Health Sciences, Graduate School of Medical Science, Kanazawa University, 5-11-80 Kodatsuno, Kanazawa, Ishikawa 920-0942, Japan
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190
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Liu W, Vierke G, Wenke AK, Thomm M, Ladenstein R. Crystal structure of the archaeal heat shock regulator from Pyrococcus furiosus: a molecular chimera representing eukaryal and bacterial features. J Mol Biol 2007; 369:474-88. [PMID: 17434531 DOI: 10.1016/j.jmb.2007.03.044] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2007] [Revised: 03/15/2007] [Accepted: 03/18/2007] [Indexed: 11/25/2022]
Abstract
We report here the crystal structure of a protein from Pyrococcus furiosus (Phr) that represents the first characterized heat shock transcription factor in archaea. Phr specifically represses the expression of heat shock genes at physiological temperature in vitro and in vivo but is released from the promoters upon heat shock response. Structure analysis revealed a stable homodimer, each subunit consisting of an N-terminal winged helix DNA-binding domain (wH-DBD) and a C-terminal antiparallel coiled coil helical domain. The overall structure shows as a molecular chimera with significant folding similarity of its DBD to the bacterial SmtB/ArsR family, while its C-terminal part was found to be a remote homologue of the eukaryotic BAG domain. The dimeric protein recognizes a palindromic DNA sequence. Molecular docking and mutational analyses suggested a novel binding mode in which the major specific contacts occur at the minor groove interacting with the strongly basic wing containing a cluster of three arginine residues.
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Affiliation(s)
- Wei Liu
- Karolinska Institutet NOVUM, Center for Structural Biochemistry, 141 57 Huddinge, Sweden.
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191
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Sakurai H, Takemori Y. Interaction between heat shock transcription factors (HSFs) and divergent binding sequences: binding specificities of yeast HSFs and human HSF1. J Biol Chem 2007; 282:13334-41. [PMID: 17347150 DOI: 10.1074/jbc.m611801200] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The target genes of the heat shock transcription factor (HSF) contain a cis-acting sequence, the heat shock element (HSE), which consists of multiple inverted repeats of the sequence 5'-nGAAn-3'. Using data acquired in this and a previous study, we have identified the HSEs in 59 of 62 target genes of Saccharomyces cerevisiae Hsf1. The Hsf1 protein recognizes continuous and discontinuous repeats of the nGAAn unit; the nucleotide sequences and configuration of the units diverge slightly among functional HSEs. When Schizosaccharomyces pombe HSF was expressed in S. cerevisiae cells, heat shock induced S. pombe HSF to bind to various HSE types, which properly activated transcription from almost all target genes, suggesting that the S. pombe genome also contains divergent HSEs. Human HSF1 induced the heat shock response via HSEs with continuous units in S. cerevisiae cells but failed to do so via HSEs with discontinuous units. Binding of human HSF1 to the discontinuous type of HSE was observed in vitro but was significantly inhibited in vivo. These results show that human HSF1 recognizes HSEs in a slightly different way than yeast HSFs and suggest that the configuration of the unit is an important determinant for HSF-HSE interactions.
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Affiliation(s)
- Hiroshi Sakurai
- Division of Health Sciences, Graduate School of Medical Science, Kanazawa University, 5-11-80 Kodatsuno, Kanazawa, Ishikawa 920-0942, Japan.
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192
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Truman AW, Millson SH, Nuttall JM, Mollapour M, Prodromou C, Piper PW. In the yeast heat shock response, Hsf1-directed induction of Hsp90 facilitates the activation of the Slt2 (Mpk1) mitogen-activated protein kinase required for cell integrity. EUKARYOTIC CELL 2007; 6:744-52. [PMID: 17293484 PMCID: PMC1865661 DOI: 10.1128/ec.00009-07] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Yeast is rendered temperature sensitive with loss of the C-terminal (CT) domain of heat shock transcription factor (Hsf1). This domain loss was found to abrogate heat stimulation of Slt2 (Mpk1), the mitogen-activated protein kinase that directs the reinforced cell integrity gene expression needed for high-temperature growth. In Hsf1 CT domain-deficient cells, Slt2 still undergoes Mkk1/2-directed dual-Thr/Tyr phosphorylation in response to the heat stimulation of cell integrity pathway signaling, but the low Hsp90 expression level suppresses any corresponding increase in Slt2 kinase activity due to Slt2 being a "client" of the Hsp90 chaperone. A non-Hsf1-directed Hsp90 overexpression restored the heat induction of Slt2 activity in these cells, as well as both Slt2-dependent (Rlm1, Swi4) and Slt2-independent (MBF) transcriptional activities. Their high-temperature growth was also rescued, not just by this Hsp90 overexpression but by osmotic stabilization, by the expression of a Slt2-independent form of the Rlm1 transcriptional regulator of cell integrity genes, and by a multicopy SLT2 gene vector. In providing the elevated Hsp90 needed for an efficient activation of Slt2, heat activation of Hsf1 indirectly facilitates (Slt2-directed) heat activation of yet another transcription factor (Rlm1). This provides an explanation as to why, in earlier transcript analysis compared to chromatin immunoprecipitation studies, many more genes of yeast displayed an Hsf1-dependent transcriptional activation by heat than bound Hsf1 directly. The levels of Hsp90 expression affecting transcription factor regulation by Hsp90 client protein kinases also provides a mechanistic model for how heat shock factor can influence the expression of several non-hsp genes in higher organisms.
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Affiliation(s)
- Andrew W Truman
- Department of Molecular Biology and Biotechnology, The University of Sheffield, Firth Court, Western Bank, Sheffield S10 2TN, United Kingdom.
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193
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Otaka M, Yamamoto S, Ogasawara K, Takaoka Y, Noguchi S, Miyazaki T, Nakai A, Odashima M, Matsuhashi T, Watanabe S, Itoh H. The induction mechanism of the molecular chaperone HSP70 in the gastric mucosa by Geranylgeranylacetone (HSP-inducer). Biochem Biophys Res Commun 2007; 353:399-404. [PMID: 17182004 DOI: 10.1016/j.bbrc.2006.12.031] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2006] [Accepted: 12/06/2006] [Indexed: 10/23/2022]
Abstract
To elucidate the induction mechanism of HSP70 by geranylgeranylacetone (GGA), we investigated GGA specific binding proteins using a GGA-affinity column. Alteration of chaperone activity of HSP70 and binding affinity of HSP70 to heat shock factor-1 (HSF-1) was evaluated in the presence or absence of GGA. The binding domain of HSP70 to GGA was also analyzed. A 70-kDa protein eluted by 10 mM GGA from the GGA-affinity column was identical to constitutively expressed HSP70 on immunoblotting. GGA-binding domain of HSP70 was C-terminal of the protein as peptide-binding domain (HSP70C). The chaperone activity of HSP70 and recombinant HSP70C was suppressed by GGA. Furthermore, dissociation of the HSP70 from HSF-1 was observed in the presence of GGA. GGA preferentially binds to the C-terminal of HSP70 which binds to HSF-1. After dissociation of HSP70, free HSF-1 could acquire the ability to bind to HSE (the promoter region of HSP70) gene.
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Affiliation(s)
- Michiro Otaka
- Department of Internal Medicine and Gastroenterology, Akita University School of Medicine, 1-1-1 Hondo, Akita City 010-8543, Japan.
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194
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Prasanth KV, Spector DL. Eukaryotic regulatory RNAs: an answer to the 'genome complexity' conundrum. Genes Dev 2007; 21:11-42. [PMID: 17210785 DOI: 10.1101/gad.1484207] [Citation(s) in RCA: 303] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
A large portion of the eukaryotic genome is transcribed as noncoding RNAs (ncRNAs). While once thought of primarily as "junk," recent studies indicate that a large number of these RNAs play central roles in regulating gene expression at multiple levels. The increasing diversity of ncRNAs identified in the eukaryotic genome suggests a critical nexus between the regulatory potential of ncRNAs and the complexity of genome organization. We provide an overview of recent advances in the identification and function of eukaryotic ncRNAs and the roles played by these RNAs in chromatin organization, gene expression, and disease etiology.
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195
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Taylor DM, De Koninck P, Minotti S, Durham HD. Manipulation of protein kinases reveals different mechanisms for upregulation of heat shock proteins in motor neurons and non-neuronal cells. Mol Cell Neurosci 2007; 34:20-33. [PMID: 17113785 DOI: 10.1016/j.mcn.2006.09.007] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2006] [Revised: 09/12/2006] [Accepted: 09/27/2006] [Indexed: 01/13/2023] Open
Abstract
Motor neurons have a high threshold for induction of heat shock proteins (Hsps) in response to stress, a property associated with impaired ability to activate heat shock transcription factor 1 (Hsf1). Hyperphosphorylation of Hsf1 has been established as a requirement for transactivation of heat shock genes. This study demonstrated that the impaired heat shock response in motor neurons is not due to altered phosphorylation of Hsf1 by kinases previously shown to affect activation of Hsf1 in other cells (PKC, GSK3beta, ERK1, CaMKIIalpha). However, a constitutively active form of CaMKIV induced robust expression of Hsp70, as well as transcription of a GFP reporter gene driven by the human inducible Hsp70 promoter in unstressed motor neurons, but not in mouse embryonic fibroblasts. The results point to novel mechanisms of activation of heat shock genes in motor neurons that have relevance to exploitation of endogenous stress responses therapeutically.
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Affiliation(s)
- David M Taylor
- Montreal Neurological Institute, McGill University, 3801 University St., Montreal, Quebec, Canada H3A 2B4
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196
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Wheeler DS, Wong HR. Heat shock response and acute lung injury. Free Radic Biol Med 2007; 42:1-14. [PMID: 17157189 PMCID: PMC1790871 DOI: 10.1016/j.freeradbiomed.2006.08.028] [Citation(s) in RCA: 75] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/28/2006] [Revised: 08/23/2006] [Accepted: 08/29/2006] [Indexed: 11/19/2022]
Abstract
All cells respond to stress through the activation of primitive, evolutionarily conserved genetic programs that maintain homeostasis and assure cell survival. Stress adaptation, which is known in the literature by a myriad of terms, including tolerance, desensitization, conditioning, and reprogramming, is a common paradigm found throughout nature, in which a primary exposure of a cell or organism to a stressful stimulus (e.g., heat) results in an adaptive response by which a second exposure to the same stimulus produces a minimal response. More interesting is the phenomenon of cross-tolerance, by which a primary exposure to a stressful stimulus results in an adaptive response whereby the cell or organism is resistant to a subsequent stress that is different from the initial stress (i.e., exposure to heat stress leading to resistance to oxidant stress). The heat shock response is one of the more commonly described examples of stress adaptation and is characterized by the rapid expression of a unique group of proteins collectively known as heat shock proteins (also commonly referred to as stress proteins). The expression of heat shock proteins is well described in both whole lungs and in specific lung cells from a variety of species and in response to a variety of stressors. More importantly, in vitro data, as well as data from various animal models of acute lung injury, demonstrate that heat shock proteins, especially Hsp27, Hsp32, Hsp60, and Hsp70 have an important cytoprotective role during lung inflammation and injury.
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Affiliation(s)
- Derek S. Wheeler
- Division of Critical Care Medicine, Cincinnati Children’s Hospital Medical Center; Kindervelt Laboratory for Critical Care Medicine Research, Children’s Hospital Research Foundation;]Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH
| | - Hector R. Wong
- Division of Critical Care Medicine, Cincinnati Children’s Hospital Medical Center; Kindervelt Laboratory for Critical Care Medicine Research, Children’s Hospital Research Foundation;]Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH
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197
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Baniwal SK, Chan KY, Scharf KD, Nover L. Role of heat stress transcription factor HsfA5 as specific repressor of HsfA4. J Biol Chem 2006; 282:3605-13. [PMID: 17150959 DOI: 10.1074/jbc.m609545200] [Citation(s) in RCA: 104] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Unlike other eukaryotes, plants possess a complex family of heat stress transcription factors (Hsfs) with usually more than 20 members. Among them, Hsfs A4 and A5 form a group distinguished from other Hsfs by structural features of their oligomerization domains and by a number of conserved signature sequences. We show that A4 Hsfs are potent activators of heat stress gene expression, whereas A5 Hsfs act as specific repressors of HsfA4 activity. The oligomerization domain of HsfA5 alone is necessary and sufficient to exert this effect. Due to the high specificity of the oligomerization domains, other class A Hsfs are not affected. Pull-down assay and yeast two-hybrid interaction tests demonstrate that the tendency to form HsfA4/A5 heterooligomers is stronger than the formation of homooligomers. The specificity of interaction between Hsfs A4 and A5 was confirmed by bimolecular fluorescence complementation experiments. The major role of the representatives of the HsfA4/A5 group, which are not involved in the conventional heat stress response, may reside in cell type-specific functions connected with the control of cell death triggered by pathogen infection and/or reactive oxygen species.
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Affiliation(s)
- Sanjeev K Baniwal
- Department of Molecular Cell Biology, Biocenter of the Goethe University, Max-von-Laue-Str. 9, D-60438 Frankfurt/M., Germany
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198
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Conlin LK, Nelson HCM. The natural osmolyte trehalose is a positive regulator of the heat-induced activity of yeast heat shock transcription factor. Mol Cell Biol 2006; 27:1505-15. [PMID: 17145780 PMCID: PMC1800720 DOI: 10.1128/mcb.01158-06] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
In Saccharomyces cerevisiae, the intracellular concentration of trehalose increases rapidly in response to many environmental stresses, including heat shock. These high trehalose levels have been correlated with tolerance to adverse conditions and led to the model that trehalose functions as a chemical cochaperone. Here, we show that the transcriptional activity of Hsf1 during the heat shock response depends on trehalose. Strains with low levels of trehalose have a diminished transcriptional response to heat shock, while strains with high levels of trehalose have an enhanced transcriptional response to heat shock. The enhanced transcriptional response does not require the other heat-responsive transcription factors Msn2/4 but is dependent upon heat and Hsf1. In addition, the phosphorylation levels of Hsf1 correlate with both transcriptional activity and the presence of trehalose. These in vivo results support a new role for trehalose, where trehalose directly modifies the dynamic range of Hsf1 activity and therefore influences heat shock protein mRNA levels in response to stress.
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Affiliation(s)
- Laura K Conlin
- University of Pennsylvania School of Medicine, Department of Biochemistry and Biophysics, 813A Stellar-Chance, 422 Curie Blvd., Philadelphia, PA 19104-6059, USA
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199
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Erkina TY, Erkine AM. Displacement of histones at promoters of Saccharomyces cerevisiae heat shock genes is differentially associated with histone H3 acetylation. Mol Cell Biol 2006; 26:7587-600. [PMID: 17015479 PMCID: PMC1636863 DOI: 10.1128/mcb.00666-06] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Chromatin remodeling at promoters of activated genes spans from mild histone modifications to outright displacement of nucleosomes in trans. Factors affecting these events are not always clear. Our results indicate that histone H3 acetylation associated with histone displacement differs drastically even between promoters of such closely related heat shock genes as HSP12, SSA4, and HSP82. The HSP12 promoter, with the highest level of histone displacement, showed the highest level of H3 acetylation, while the SSA4 promoter, with a lower histone displacement, showed only modest H3 acetylation. Moreover, for the HSP12 promoter, the level of acetylated H3 is temporarily increased prior to nucleosome departure. Individual promoters in strains expressing truncated versions of heat shock factor (HSF) showed that deletion of either one of two activating regions in HSF led to the diminished histone displacement and correspondingly lower H3 acetylation. The deletion of both regions simultaneously severely decreased histone displacement for all promoters tested, showing the dependence of these processes on HSF. The level of histone H3 acetylation at individual promoters in strains expressing truncated HSF also correlated with the extent of histone displacement. The beginning of chromatin remodeling coincides with the polymerase II loading on heat shock gene promoters and is regulated either by HSF binding or activation of preloaded HSF.
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Affiliation(s)
- T Y Erkina
- Division of Basic Biomedical Sciences, University of South Dakota, Sanford School of Medicine, 414 E. Clark St., Vermillion, SD 57069, USA
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200
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Batulan Z, Taylor DM, Aarons RJ, Minotti S, Doroudchi MM, Nalbantoglu J, Durham HD. Induction of multiple heat shock proteins and neuroprotection in a primary culture model of familial amyotrophic lateral sclerosis. Neurobiol Dis 2006; 24:213-25. [PMID: 16950627 DOI: 10.1016/j.nbd.2006.06.017] [Citation(s) in RCA: 83] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2006] [Revised: 05/29/2006] [Accepted: 06/28/2006] [Indexed: 11/24/2022] Open
Abstract
High threshold for stress-induced activation of the heat shock transcription factor, Hsf1, may contribute to vulnerability of motor neurons to disease and limit efficacy of agents promoting expression of neuroprotective heat shock proteins (Hsps) through this transcription factor. Plasmid encoding a constitutively active form of Hsf1, Hsf1act, and chemicals shown to activate Hsf1 in other cells were investigated in a primary culture model of familial amyotrophic lateral sclerosis. Hsf1act and the Hsp90 inhibitor, geldanamycin, induced high expression of multiple Hsps in cultured motor neurons and conferred dramatic neuroprotection against SOD1G93A in comparison to Hsp70 or Hsp25 alone. Two other Hsp90 inhibitors, 17-allylamino-17-demethoxygeldanamycin (17-AAG) and radicicol, and pyrrolidine dithiocarbamate induced robust expression of Hsp70 and Hsp40 in motor neurons, but at cytotoxic concentrations. 17-AAG, which penetrates the blood-brain barrier, has exhibited a higher therapeutic index than geldanamycin, but this may not be the case when activation of Hsf1 in neurons is targeted.
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Affiliation(s)
- Zarah Batulan
- Montreal Neurological Institute, McGill University, 3801 University St., Montreal, Quebec, Canada H3A 2B4
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