1
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Chen YM, Wong CC, Weng PW, Chiang CW, Lin PY, Lee PW, Jheng PR, Hao PC, Chen YT, Cho EC, Chuang EY. Bioinspired and self-restorable alginate-tyramine hydrogels with plasma reinforcement for arthritis treatment. Int J Biol Macromol 2023; 250:126105. [PMID: 37549762 DOI: 10.1016/j.ijbiomac.2023.126105] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2023] [Revised: 07/28/2023] [Accepted: 07/31/2023] [Indexed: 08/09/2023]
Abstract
Long-standing administration of disease-modifying antirheumatic drugs confirms their clinical value for managing rheumatoid arthritis (RA). Nevertheless, there are emergent worries over unwanted adverse risks of systemic drug administration. Hence, a novel strategy that can be used in a drug-free manner while diminishing side effects is immediately needed, but challenges persist in the therapy for RA. To this end, herein we conjugated tyramine (TYR) with alginate (ALG) to form ALG-TYR and then treated it for 5 min with oxygen plasma (ALG-TYR + P/5 min). It was shown that the ALG-TYR + P/5 min hydrogel exhibited favorable viscoelastic, morphological, mechanical, biocompatible, and cellular heat-shock protein amplification behaviors. A thorough physical and structural analysis was conducted on the ALG-TYR + P/5 min hydrogel, revealing favorable physical characteristics and uniform porous structural features within the hydrogel. Moreover, ALG-TYR + P/5 min not only effectively inhibited inflammation of RA but also potentially regulated lesion immunity. Once ALG-TYR + P/5 min was intra-articularly administered to joints of rats with zymosan-induced arthritis, we observed that ALG-TYR + P/5 min could ameliorate syndromes of RA joint. This bioinspired and self-restorable ALG-TYR + P/5 min hydrogel can thus serve as a promising system to provide prospective outcomes to potentiate RA therapy.
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Affiliation(s)
- Yu-Ming Chen
- Graduate Institute of Biomedical Materials and Tissue Engineering, International Ph.D. Program in Biomedical Engineering, Graduate Institute of Nanomedicine and Medical Engineering, College of Biomedical Engineering, Taipei Medical University, Taipei 11031, Taiwan
| | - Chin-Chean Wong
- Department of Orthopedics, Shuang Ho Hospital, Taipei Medical University, New Taipei City 23561, Taiwan; Department of Orthopedics, School of Medicine, College of Medicine, Taipei Medical University, Taipei 11031, Taiwan; Research Center of Biomedical Devices, Taipei Medical University, Taipei 11031, Taiwan; International Ph.D. Program for Cell Therapy and Regenerative Medicine, College of Medicine, Taipei Medical University, Taipei 11031, Taiwan
| | - Pei-Wei Weng
- Graduate Institute of Biomedical Materials and Tissue Engineering, International Ph.D. Program in Biomedical Engineering, Graduate Institute of Nanomedicine and Medical Engineering, College of Biomedical Engineering, Taipei Medical University, Taipei 11031, Taiwan; Department of Orthopedics, Shuang Ho Hospital, Taipei Medical University, New Taipei City 23561, Taiwan; Department of Orthopedics, School of Medicine, College of Medicine, Taipei Medical University, Taipei 11031, Taiwan; Research Center of Biomedical Devices, Taipei Medical University, Taipei 11031, Taiwan; International Ph.D. Program for Cell Therapy and Regenerative Medicine, College of Medicine, Taipei Medical University, Taipei 11031, Taiwan
| | - Chih-Wei Chiang
- Bone and Joint Research Center, Department of Orthopedics, Taipei Medical University Hospital, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan
| | - Po-Yen Lin
- BioGend Therapeutics Co., New Taipei City 23561, Taiwan
| | - Po-Wei Lee
- BioGend Therapeutics Co., New Taipei City 23561, Taiwan
| | - Pei-Ru Jheng
- Graduate Institute of Biomedical Materials and Tissue Engineering, International Ph.D. Program in Biomedical Engineering, Graduate Institute of Nanomedicine and Medical Engineering, College of Biomedical Engineering, Taipei Medical University, Taipei 11031, Taiwan
| | - Ping-Chien Hao
- Graduate Institute of Biomedical Materials and Tissue Engineering, International Ph.D. Program in Biomedical Engineering, Graduate Institute of Nanomedicine and Medical Engineering, College of Biomedical Engineering, Taipei Medical University, Taipei 11031, Taiwan
| | - Yan-Ting Chen
- Graduate Institute of Biomedical Materials and Tissue Engineering, International Ph.D. Program in Biomedical Engineering, Graduate Institute of Nanomedicine and Medical Engineering, College of Biomedical Engineering, Taipei Medical University, Taipei 11031, Taiwan
| | - Er-Chen Cho
- Graduate Institute of Biomedical Materials and Tissue Engineering, International Ph.D. Program in Biomedical Engineering, Graduate Institute of Nanomedicine and Medical Engineering, College of Biomedical Engineering, Taipei Medical University, Taipei 11031, Taiwan
| | - Er-Yuan Chuang
- Graduate Institute of Biomedical Materials and Tissue Engineering, International Ph.D. Program in Biomedical Engineering, Graduate Institute of Nanomedicine and Medical Engineering, College of Biomedical Engineering, Taipei Medical University, Taipei 11031, Taiwan; Cell Physiology and Molecular Image Research Center, Taipei Medical University, Wan Fang Hospital, Taipei 11696, Taiwan.
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2
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Peng S, Woodruff J, Pathak PK, Matts RL, Deng J. Crystal structure of the middle and C-terminal domains of Hsp90α labeled with a coumarin derivative reveals a potential allosteric binding site as a drug target. Acta Crystallogr D Struct Biol 2022; 78:571-585. [PMID: 35503206 PMCID: PMC9063849 DOI: 10.1107/s2059798322002261] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2021] [Accepted: 02/26/2022] [Indexed: 12/01/2022] Open
Abstract
The 90 kDa heat-shock protein (Hsp90) is an abundant molecular chaperone that is essential to activate, stabilize and regulate the function of a plethora of client proteins. As drug targets for the treatment of cancer and neurodegenerative diseases, Hsp90 inhibitors that bind to the N-terminal ATP-binding site of Hsp90 have shown disappointing efficacy in clinical trials. Thus, allosteric regulation of the function of Hsp90 by compounds that interact with its middle and C-terminal (MC) domains is now being pursued as a mechanism to inhibit the ATPase activity and client protein-binding activity of Hsp90 without concomitant induction of the heat-shock response. Here, the crystal structure of the Hsp90αMC protein covalently linked to a coumarin derivative, MDCC {7-diethylamino-3-[N-(2-maleimidoethyl)carbamoyl]coumarin}, which is located in a hydrophobic pocket that is formed at the Hsp90αMC hexamer interface, is reported. MDCC binding leads to the hexamerization of Hsp90, and the stabilization and conformational changes of three loops that are critical for its function. A fluorescence competition assay demonstrated that other characterized coumarin and isoflavone-containing Hsp90 inhibitors compete with MDCC binding, suggesting that they could bind at a common site or that they might allosterically alter the structure of the MDCC binding site. This study provides insights into the mechanism by which the coumarin class of allosteric inhibitors potentially disrupt the function of Hsp90 by regulating its oligomerization and the burial of interaction sites involved in the ATP-dependent folding of Hsp90 clients. The hydrophobic binding pocket characterized here will provide new structural information for future drug design.
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Affiliation(s)
- Shuxia Peng
- Department of Biochemistry and Molecular Biology, Oklahoma State University, 246 Noble Research Center, Stillwater, OK 74078, USA
| | - Jeff Woodruff
- Department of Biochemistry and Molecular Biology, Oklahoma State University, 246 Noble Research Center, Stillwater, OK 74078, USA
| | - Prabhat Kumar Pathak
- Department of Biochemistry and Molecular Biology, Oklahoma State University, 246 Noble Research Center, Stillwater, OK 74078, USA
| | - Robert L. Matts
- Department of Biochemistry and Molecular Biology, Oklahoma State University, 246 Noble Research Center, Stillwater, OK 74078, USA
| | - Junpeng Deng
- Department of Biochemistry and Molecular Biology, Oklahoma State University, 246 Noble Research Center, Stillwater, OK 74078, USA
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3
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Lepvrier E, Thomas D, Garnier C. Hsp90 Quaternary Structures and the Chaperone Cycle: Highly Flexible Dimeric and Oligomeric Structures and Their Regulation by Co-Chaperones. CURR PROTEOMICS 2018. [DOI: 10.2174/1570164615666180522095147] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Proposed models of the function of Hsp90 are characterised by high flexibility of the dimeric
state and conformational changes regulated by both nucleotide binding and hydrolysis, and by
co-chaperone interactions. In addition to its dimeric state, Hsp90 self-associates upon particular stimuli.
The Hsp90 dimer is the building block up to the hexamer that we named “cosy nest”, and the dodecamer
results from the association of two hexamers. Oligomers exhibit chaperone activity, but their
exact mechanism of action has not yet been determined. One of the best ways to elucidate how oligomers
might operate is to study their interactions with co-chaperone proteins known to regulate the
Hsp90 chaperone cycle, such as p23 and Aha1. In this review, we summarise recent results and conclude
that Hsp90 oligomers are key players in the chaperone cycle. Crucible-shaped quaternary structures
likely provide an ideal environment for client protein accommodation and folding, as is the case
for other Hsp families. Confirmation of the involvement of Hsp90 oligomers in the chaperone cycle
and a better understanding of their functionality will allow us to address some of the more enigmatic
aspects of Hsp90 activity. Utilising this knowledge, future work will highlight how Hsp90 oligomers
and co-chaperones cooperate to build the structures required to fold or refold numerous different client
proteins.
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Affiliation(s)
- Eléonore Lepvrier
- Structure et Dynamique des Macromolecules, UMR-CNRS 6026, Interactions Cellulaires et Moleculaires, Universite de Rennes 1, Campus Beaulieu, 35042 Rennes Cedex, France
| | - Daniel Thomas
- Structure et Dynamique des Macromolecules, UMR-CNRS 6026, Interactions Cellulaires et Moleculaires, Universite de Rennes 1, Campus Beaulieu, 35042 Rennes Cedex, France
| | - Cyrille Garnier
- Universite de Rennes 1, Campus de Beaulieu, F-35042 Rennes Cedex, France
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4
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Abstract
The molecular chaperone Hsp90 is an essential member of the cellular proteostasis system. It plays an important role in the stabilisation and activation of a large number of client proteins and is involved in fatal disease processes, e.g. Alzheimer disease, cancer and cystic fibrosis. This makes Hsp90 a crucial protein to study. Mechanistic studies require large amounts of protein but the production and purification of recombinant human Hsp90 in Escherichia coli is challenging and laborious. Here we identified conditions that influence Hsp90 production, and optimised a fast and efficient purification protocol. We found that the nutrient value of the culturing medium and the length of induction had significant effect on Hsp90 production in Escherichia coli. Our fast, single-day purification protocol resulted in a stable, well-folded and pure sample that was resistant to degradation in a reproducible manner. We anticipate that our results provide a useful tool to produce higher amount of pure, well-folded and stable recombinant human Hsp90β in Escherichia coli in an efficient way.
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Affiliation(s)
- Martina Radli
- Cellular Protein Chemistry, Bijvoet Center for Biomolecular Research, Utrecht University, Padualaan 8, CH Utrecht, The Netherlands
- Science for Life, Utrecht University, CH Utrecht, The Netherlands
| | - Dmitry B. Veprintsev
- Laboratory of Biomolecular Research, Paul Scherrer Institut, Villigen PSI, Switzerland
- Department of Biology, ETH Zürich, Zürich, Switzerland
| | - Stefan G. D. Rüdiger
- Cellular Protein Chemistry, Bijvoet Center for Biomolecular Research, Utrecht University, Padualaan 8, CH Utrecht, The Netherlands
- Science for Life, Utrecht University, CH Utrecht, The Netherlands
- * E-mail:
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5
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Rybarczyk P, Vanlaeys A, Brassart B, Dhennin-Duthille I, Chatelain D, Sevestre H, Ouadid-Ahidouch H, Gautier M. The Transient Receptor Potential Melastatin 7 Channel Regulates Pancreatic Cancer Cell Invasion through the Hsp90α/uPA/MMP2 pathway. Neoplasia 2017; 19:288-300. [PMID: 28284058 PMCID: PMC5345960 DOI: 10.1016/j.neo.2017.01.004] [Citation(s) in RCA: 50] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2016] [Revised: 01/05/2017] [Accepted: 01/13/2017] [Indexed: 12/28/2022] Open
Abstract
Pancreatic ductal adenocarcinoma (PDAC) is an aggressive malignancy with a very poor prognosis. There is an urgent need to better understand the molecular mechanisms that regulate PDAC cell aggressiveness. The transient receptor potential melastatin 7 (TRPM7) is a nonselective cationic channel that mainly conducts Ca2+ and Mg2+. TRPM7 is overexpressed in numerous malignancies including PDAC. In the present study, we used the PANC-1 and MIA PaCa-2 cell lines to specifically assess the role of TRPM7 in cell invasion and matrix metalloproteinase secretion. We show that TRPM7 regulates Mg2+ homeostasis and constitutive cation entry in both PDAC cell lines. Moreover, cell invasion is strongly reduced by TRPM7 silencing without affecting the cell viability. Conditioned media were further studied, by gel zymography, to detect matrix metalloproteinase (MMP) secretion in PDAC cells. Our results show that MMP-2, urokinase plasminogen activator (uPA), and heat-shock protein 90α (Hsp90α) secretions are significantly decreased in TRPM7-deficient PDAC cells. Moreover, TRPM7 expression in human PDAC lymph node metastasis is correlated to the channel expression in primary tumor. Taken together, our results show that TRPM7 is involved in PDAC cell invasion through regulation of Hsp90α/uPA/MMP-2 proteolytic axis, confirming that this channel could be a promising biomarker and possibly a target for PDAC metastasis therapy.
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Affiliation(s)
- Pierre Rybarczyk
- Laboratoire de Physiologie Cellulaire et Moléculaire-EA4667, UFR Sciences, Université de Picardie Jules Verne, F-80039 Amiens, France; SFR CAP-Santé (FED 4231)
| | - Alison Vanlaeys
- Laboratoire de Physiologie Cellulaire et Moléculaire-EA4667, UFR Sciences, Université de Picardie Jules Verne, F-80039 Amiens, France; SFR CAP-Santé (FED 4231)
| | - Bertrand Brassart
- SFR CAP-Santé (FED 4231); UMR CNRS 7369 Matrice Extracellulaire et Dynamique Cellulaire (MEDyC), Université de Reims Champagne Ardenne (URCA), F-51095 Reims, France
| | - Isabelle Dhennin-Duthille
- Laboratoire de Physiologie Cellulaire et Moléculaire-EA4667, UFR Sciences, Université de Picardie Jules Verne, F-80039 Amiens, France; SFR CAP-Santé (FED 4231)
| | - Denis Chatelain
- Service d'anatomie pathologique, CHU d'Amiens, Université de Picardie Jules Verne, F-80000 Amiens, France, France
| | - Henri Sevestre
- Laboratoire de Physiologie Cellulaire et Moléculaire-EA4667, UFR Sciences, Université de Picardie Jules Verne, F-80039 Amiens, France; SFR CAP-Santé (FED 4231); Service d'anatomie pathologique, CHU d'Amiens, Université de Picardie Jules Verne, F-80000 Amiens, France, France
| | - Halima Ouadid-Ahidouch
- Laboratoire de Physiologie Cellulaire et Moléculaire-EA4667, UFR Sciences, Université de Picardie Jules Verne, F-80039 Amiens, France; SFR CAP-Santé (FED 4231)
| | - Mathieu Gautier
- Laboratoire de Physiologie Cellulaire et Moléculaire-EA4667, UFR Sciences, Université de Picardie Jules Verne, F-80039 Amiens, France; SFR CAP-Santé (FED 4231).
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6
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Hsp90 directly interacts, in vitro, with amyloid structures and modulates their assembly and disassembly. Biochim Biophys Acta Gen Subj 2016; 1860:2598-2609. [DOI: 10.1016/j.bbagen.2016.07.033] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2016] [Revised: 07/27/2016] [Accepted: 07/28/2016] [Indexed: 01/22/2023]
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7
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Lo HF, Chen BE, Lin MG, Chi MC, Wang TF, Lin LL. Gene expression and molecular characterization of a chaperone protein HtpG from Bacillus licheniformis. Int J Biol Macromol 2015; 85:179-91. [PMID: 26743745 DOI: 10.1016/j.ijbiomac.2015.12.080] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2015] [Revised: 12/24/2015] [Accepted: 12/24/2015] [Indexed: 11/16/2022]
Abstract
Heat shock protein 90 (Hsp90/HtpG) is a highly abundant and ubiquitous ATP-dependent molecular chaperone consisting of three flexibly linked regions, an N-terminal nucleotide-binding domain, middle domain, and a C-terminal domain. Here the putative htpG gene of Bacillus licheniformis was cloned and heterologously expressed in Escherichia coli M15 cells. Native-gel electrophoresis, size exclusion chromatography, and cross-linking analysis revealed that the recombinant protein probably exists as a mixture of monomer, dimer and other oligomers in solution. The optimal conditions for the ATPase activity of B. licheniformis HtpG (BlHtpG) were 45°C and pH 7.0 in the presence of 0.5mM Mg(2+) ions. The molecular architecture of this protein was stable at higher temperatures with a transition point (Tm) of 45°C at neutral pH, whereas the Tm value was reduced to 40.8°C at pH 10.5. Acrylamide quenching experiment further indicated that the dynamic quenching constant (Ksv) of BlHtpG became larger at higher pH values. BlHtpG also experienced a significant change in the protein conformation upon the addition of ATP and organic solvents. Collectively, our experiment data may provide insights into the molecular properties of BlHtpG and identify the alteration of protein structure to forfeit the ATPase activity at alkaline conditions.
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Affiliation(s)
- Hui-Fen Lo
- Department of Food Science and Technology, Hungkuang University, 1018 Taiwan Boulevard, Shalu District, Taichung 43302, Taiwan
| | - Bo-En Chen
- Department of Applied Chemistry, National Chiayi University, 300 Syuefu Road, Chiayi 60004, Taiwan
| | - Min-Guan Lin
- Institute of Molecular Biology, Academia Sinica, Nangang District, Taipei 11529, Taiwan
| | - Meng-Chun Chi
- Department of Applied Chemistry, National Chiayi University, 300 Syuefu Road, Chiayi 60004, Taiwan
| | - Tzu-Fan Wang
- Department of Chemistry, National Cheng Kung University, Tainan 701, Taiwan.
| | - Long-Liu Lin
- Department of Applied Chemistry, National Chiayi University, 300 Syuefu Road, Chiayi 60004, Taiwan.
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8
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Lepvrier E, Nigen M, Moullintraffort L, Chat S, Allegro D, Barbier P, Thomas D, Nazabal A, Garnier C. Hsp90 oligomerization process: How can p23 drive the chaperone machineries? BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2015; 1854:1412-24. [PMID: 26151834 DOI: 10.1016/j.bbapap.2015.07.003] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/08/2015] [Revised: 06/28/2015] [Accepted: 07/02/2015] [Indexed: 01/16/2023]
Abstract
The 90-kDa heat shock protein (Hsp90) is a highly flexible dimer that is able to self-associate in the presence of divalent cations or under heat shock. In a previous work, we focused on the Mg2+-induced oligomerization process of Hsp90, and characterized the oligomers. Combining analytical ultracentrifugation, size-exclusion chromatography coupled to multi-angle laser light scattering and high-mass matrix-assisted laser desorption/ionization time-of-flight mass spectrometry, we studied the interaction of p23 with both Hsp90 dimer and oligomers. Even if p23 predominantly binds the Hsp90 dimer, we demonstrated, for the first time, that p23 is also able to interact with Hsp90 oligomers, shifting the Hsp90 dimer-oligomers equilibrium toward dimer. Our results showed that the Hsp90:p23 binding stoichiometry decreases with the Hsp90 oligomerization degree. Therefore, we propose a model in which p23 would act as a "protein wedge" regarding the Hsp90 dimer closure and the Hsp90 oligomerization process.
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Affiliation(s)
- Eléonore Lepvrier
- Translation and Folding, UMR-CNRS 6290, Université de Rennes 1, Campus Beaulieu, 35042 Rennes Cedex, France
| | - Michaël Nigen
- UMR1208 Ingénierie des Agropolymères et Technologies Emergentes INRA-Montpellier SupAgro-CIRAD-Université Montpellier, 2 Place Pierre Viala, F-34060 Montpellier, France
| | - Laura Moullintraffort
- Translation and Folding, UMR-CNRS 6290, Université de Rennes 1, Campus Beaulieu, 35042 Rennes Cedex, France
| | - Sophie Chat
- Translation and Folding, UMR-CNRS 6290, Université de Rennes 1, Campus Beaulieu, 35042 Rennes Cedex, France
| | - Diane Allegro
- Aix-Marseille Université, INSERM UMR 911, Centre de Recherche en Oncologie biologique et Onco-pharmacologie, 13385 Marseille Cedex 5, France
| | - Pascale Barbier
- Aix-Marseille Université, INSERM UMR 911, Centre de Recherche en Oncologie biologique et Onco-pharmacologie, 13385 Marseille Cedex 5, France
| | - Daniel Thomas
- Translation and Folding, UMR-CNRS 6290, Université de Rennes 1, Campus Beaulieu, 35042 Rennes Cedex, France
| | | | - Cyrille Garnier
- Translation and Folding, UMR-CNRS 6290, Université de Rennes 1, Campus Beaulieu, 35042 Rennes Cedex, France.
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9
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Lepvrier E, Moullintraffort L, Nigen M, Goude R, Allegro D, Barbier P, Peyrot V, Thomas D, Nazabal A, Garnier C. Hsp90 Oligomers Interacting with the Aha1 Cochaperone: An Outlook for the Hsp90 Chaperone Machineries. Anal Chem 2015; 87:7043-51. [PMID: 26076190 DOI: 10.1021/acs.analchem.5b00051] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
The 90-kDa heat shock protein (Hsp90) is a highly flexible dimer able to self-associate in the presence of divalent cations or under heat shock. This study investigated the relationship between Hsp90 oligomers and the Hsp90 cochaperone Aha1 (activator of Hsp90 ATPase). The interactions of Aha1 with Hsp90 dimers and oligomers were evaluated by ultracentrifugation, size-exclusion chromatography coupled to multiangle laser light scattering and high-mass matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. Hsp90 dimer was able to bind up to four Aha1 molecules, and Hsp90 oligomers are also able to interact with Aha1. The binding of Aha1 did not interfere with the Hsp90 oligomerization process. Except for Hsp90 dimer, the stoichiometry of the interaction remained constant, at 2 Aha1 molecules per Hsp90 dimer, regardless of the degree of Hsp90 oligomerization. Moreover, Aha1 predominantly bound to Hsp90 oligomers. Thus, the ability of Hsp90 oligomers to bind the Aha1 ATPase activator reinforces their role within the Hsp90 chaperone machineries.
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Affiliation(s)
- Eléonore Lepvrier
- †Translation and Folding, UMR-CNRS 6290, Université de Rennes 1, Campus Beaulieu, 263 Avenue du Général Leclerc, 35042 Rennes, Cedex, France
| | - Laura Moullintraffort
- †Translation and Folding, UMR-CNRS 6290, Université de Rennes 1, Campus Beaulieu, 263 Avenue du Général Leclerc, 35042 Rennes, Cedex, France
| | - Michaël Nigen
- ‡UMR1208 Ingénierie des Agropolymères et Technologies Emergentes INRA-Montpellier SupAgro-CIRAD, Université Montpellier, 2 Place Pierre Viala, F-34060 Montpellier, France
| | - Renan Goude
- §Microbiologie risques infectieux, EA 1254, Université de Rennes 1, Campus Beaulieu, 35042 Rennes, Cedex, France
| | - Diane Allegro
- ∥Aix-Marseille Université, INSERM UMR 911, Centre de Recherche en Oncologie biologique et Onco-pharmacologie, 13385 Marseille, Cedex 5, France
| | - Pascale Barbier
- ∥Aix-Marseille Université, INSERM UMR 911, Centre de Recherche en Oncologie biologique et Onco-pharmacologie, 13385 Marseille, Cedex 5, France
| | - Vincent Peyrot
- ∥Aix-Marseille Université, INSERM UMR 911, Centre de Recherche en Oncologie biologique et Onco-pharmacologie, 13385 Marseille, Cedex 5, France
| | - Daniel Thomas
- †Translation and Folding, UMR-CNRS 6290, Université de Rennes 1, Campus Beaulieu, 263 Avenue du Général Leclerc, 35042 Rennes, Cedex, France
| | | | - Cyrille Garnier
- †Translation and Folding, UMR-CNRS 6290, Université de Rennes 1, Campus Beaulieu, 263 Avenue du Général Leclerc, 35042 Rennes, Cedex, France
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10
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Lepvrier E, Doigneaux C, Moullintraffort L, Nazabal A, Garnier C. Optimized Protocol for Protein Macrocomplexes Stabilization Using the EDC, 1-Ethyl-3-(3-(dimethylamino)propyl)carbodiimide, Zero-Length Cross-Linker. Anal Chem 2014; 86:10524-30. [DOI: 10.1021/ac502561e] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Affiliation(s)
- Eléonore Lepvrier
- Translation
and Folding, UMR-CNRS 6290, Université de Rennes 1, 35042 Rennes Cedex, France
| | - Cyrielle Doigneaux
- Translation
and Folding, UMR-CNRS 6290, Université de Rennes 1, 35042 Rennes Cedex, France
| | - Laura Moullintraffort
- Translation
and Folding, UMR-CNRS 6290, Université de Rennes 1, 35042 Rennes Cedex, France
| | | | - Cyrille Garnier
- Translation
and Folding, UMR-CNRS 6290, Université de Rennes 1, 35042 Rennes Cedex, France
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11
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Zanphorlin LM, Alves FR, Ramos CHI. The effect of celastrol, a triterpene with antitumorigenic activity, on conformational and functional aspects of the human 90kDa heat shock protein Hsp90α, a chaperone implicated in the stabilization of the tumor phenotype. Biochim Biophys Acta Gen Subj 2014; 1840:3145-52. [PMID: 24954307 DOI: 10.1016/j.bbagen.2014.06.008] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2014] [Revised: 05/23/2014] [Accepted: 06/11/2014] [Indexed: 10/25/2022]
Abstract
BACKGROUND Hsp90 is a molecular chaperone essential for cell viability in eukaryotes that is associated with the maturation of proteins involved in important cell functions and implicated in the stabilization of the tumor phenotype of various cancers, making this chaperone a notably interesting therapeutic target. Celastrol is a plant-derived pentacyclic triterpenoid compound with potent antioxidant, anti-inflammatory and anticancer activities; however, celastrol's action mode is still elusive. RESULTS In this work, we investigated the effect of celastrol on the conformational and functional aspects of Hsp90α. Interestingly, celastrol appeared to target Hsp90α directly as the compound induced the oligomerization of the chaperone via the C-terminal domain as demonstrated by experiments using a deletion mutant. The nature of the oligomers was investigated by biophysical tools demonstrating that a two-fold excess of celastrol induced the formation of a decameric Hsp90α bound throughout the C-terminal domain. When bound, celastrol destabilized the C-terminal domain. Surprisingly, standard chaperone functional investigations demonstrated that neither the in vitro chaperone activity of protecting against aggregation nor the ability to bind a TPR co-chaperone, which binds to the C-terminus of Hsp90α, were affected by celastrol. CONCLUSION Celastrol interferes with specific biological functions of Hsp90α. Our results suggest a model in which celastrol binds directly to the C-terminal domain of Hsp90α causing oligomerization. However, the ability to protect against protein aggregation (supported by our results) and to bind to TPR co-chaperones are not affected by celastrol. Therefore celastrol may act primarily by inducing specific oligomerization that affects some, but not all, of the functions of Hsp90α. GENERAL SIGNIFICANCE To the best of our knowledge, this study is the first work to use multiple probes to investigate the effect that celastrol has on the stability and oligomerization of Hsp90α and on the binding of this chaperone to Tom70. This work provides a novel mechanism by which celastrol binds Hsp90α.
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Affiliation(s)
- Letícia M Zanphorlin
- Institute of Chemistry, University of Campinas UNICAMP, P.O. Box 6154, 13083-970 Campinas, SP, Brazil
| | - Fernanda R Alves
- Institute of Chemistry, University of Campinas UNICAMP, P.O. Box 6154, 13083-970 Campinas, SP, Brazil
| | - Carlos H I Ramos
- Institute of Chemistry, University of Campinas UNICAMP, P.O. Box 6154, 13083-970 Campinas, SP, Brazil.
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Khalid S, Paul S. Identifying a C-terminal ATP binding sites-based novel Hsp90-Inhibitor in silico: a plausible therapeutic approach in Alzheimer's disease. Med Hypotheses 2014; 83:39-46. [PMID: 24785461 DOI: 10.1016/j.mehy.2014.04.013] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2014] [Revised: 03/07/2014] [Accepted: 04/06/2014] [Indexed: 02/02/2023]
Abstract
BACKGROUND Alzheimer's disease (AD) is a progressive brain disorder, which gradually and irreversibly destroys the intellectual and cognitive abilities of the brain. Heat shock protein 90 (Hsp90α) is a molecular chaperone which was found to regulate the function of number of client proteins including tau that is involved in the cause of the AD. Inhibition of Hsp90α by C-Terminal domain (CTD) ATP binding-site blockage might be used as an effective treatment strategy against the disease via degradation of tau proteins that are involved in the progression of the disease. Till date, a variety of drugs have been identified as Hsp90α inhibitors, which include Novobiocin, Clorobiocin, Epigallocatechingallate (EGCG) and Derrubone. However, which drug among the four binds to the CTD ATP binding site strongly and what are the specific residue responsible for such binding, have not been reported so far. HYPOTHESIS We hypothesize that binding site for ATP of Hsp90α CTD contains multiple ATP binding sites. We also hypothesize that a drug which can bind to the ATP binding site of CTD strongly can inhibit Hsp90α function which is in turn redirects towards the proteasomal degradation of diseased client protein like tau in AD. Such inhibition will find a novel therapeutic approach in the treatment of AD. EXPERIMENTAL DESIGN The identification of ATP binding site of Hsp90α CTD was done using various software tools like Hex 6.3, CastP, protein Hydrophobicity plots, ATPint and LigPlot+ v.1.4.5. Docking experiments were conducted between Hsp90αCTD and its inhibitors at these ATP binding site using the Autodock 4.0. The docking energies were further compared to obtain the most effective Hsp90α inhibitor of CTD. RESULTS From our experiments, Leucine (Leu) 665, Leu 666 and Leu 694 were predicted to be located in CTD ATP binding site. Furthermore, docking studies were performed of various Hsp90α inhibitors like Novobiocin, Clorobiocin, Epigallocatechingallate (EGCG) and Derrubone with the previously recognized ATP binding residues of CTD i.e. Leu 665, Leu 666 and Leu 694. The docking results of Derrubone showed the highest binding energy at all the three sites of ATP interaction. Additionally, Derrubone showed the best binding energy at Leu 666 (-7.53kcal/mol) compared to Leu 665 (-7.20kcal/mol) and Leu 694 (-6.67kcal/mol). CONCLUSION Based on our findings, we propose that the recognized sites i.e. Leu665, Leu 666 and Leu694 could possibly be the binding sites of Hsp90α CTD for ATP and the Hsp90 inhibitors. It was predicted that Derrubone could bind with CTD of Hsp90α strongly and resulted tau protein degradation which might be considered to be a therapeutic approach in AD.
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Affiliation(s)
- Shumaila Khalid
- Structural Biology and Nanomedicine Laboratory, Department of Biotechnology and Medical Engineering, National Institute of Technology Rourkela, Rourkela 769008, India
| | - Subhankar Paul
- Structural Biology and Nanomedicine Laboratory, Department of Biotechnology and Medical Engineering, National Institute of Technology Rourkela, Rourkela 769008, India.
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Ho WH, Lee DY, Chang GD. Proteomic identification of a novel hsp90-containing protein-mineral complex which can be induced in cells in response to massive calcium influx. J Proteome Res 2012; 11:3160-74. [PMID: 22533508 DOI: 10.1021/pr201201y] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Fetuin-A is known for limiting the expansion and formation of hydroxyapatite crystals from calcium phosphate aggregates in circulation by forming a soluble fetuin-mineral complex. This study was aimed to uncover potential proteins involved in the regulation of calcium phosphate precipitation within cells. We found that a novel protein-mineral complex (PMC) can be generated after introduction of calcium chloride and sodium phosphate into the porcine brain protein extract prepared in Tris-HCl buffer. Selectively enriched proteins in the pellet were confirmed by immunoblotting, including heat shock protein 90 (Hsp90), annexin A5, calreticulin, nucleolin, and other proteins. In addition, purified native Hsp90 directly bound both amorphous calcium phosphate and hydroxyapatite and underwent conformational changes and oligomerization in the presence of excess calcium and phosphate. The morphology of the PMC prepared from Hsp90, calcium, and phosphate was distinctly different from that of hydroxyapatite under transmission electron microscope observation. When cultured SiHa cells were treated with a calcium ionophore or damaged by scratch to induce the massive calcium influx, a complex was formed and observed at discrete sites near the plasma membrane as revealed by antibodies against Hsp90, annexin A5, calreticulin, nucleolin, and other proteins. This complex could also be probed in situ with fetuin-A suggesting the existence of calcium phosphate aggregates in this complex. Inhibition of the complex formation by bisphosphonates hindered cell recovery from A23187 assault. Our results show that following membrane damage amorphous calcium phosphate develops at sites near membrane rupture where saturated calcium phosphate concentration is achieved. As a result, Hsp90 and other proteins are recruited, and the cytosolic PMC is formed. Inhibition of the cytosolic PMC formation may in part contribute to the cellular toxicity and in vivo side effects of bisphosphonates, particularly in cells prone to membrane damage under physiological conditions such as gastrointestinal epithelial and oral cavity epithelial cells.
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Affiliation(s)
- Wen-Hsiung Ho
- Graduate Institute of Biochemical Sciences and ‡Center for Systems Biology, National Taiwan University No. 1 , Section 4, Roosevelt Road, Taipei 106, Taiwan
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Moullintraffort L, Bruneaux M, Nazabal A, Allegro D, Giudice E, Zal F, Peyrot V, Barbier P, Thomas D, Garnier C. Biochemical and biophysical characterization of the Mg2+-induced 90-kDa heat shock protein oligomers. J Biol Chem 2010; 285:15100-15110. [PMID: 20228408 DOI: 10.1074/jbc.m109.094698] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
The 90-kDa heat shock protein (Hsp90) is involved in the regulation and activation of numerous client proteins essential for diverse functions such as cell growth and differentiation. Although the function of cytosolic Hsp90 is dependent on a battery of cochaperone proteins regulating both its ATPase activity and its interaction with client proteins, little is known about the real Hsp90 molecular mechanism. Besides its highly flexible dimeric state, Hsp90 is able to self-oligomerize in the presence of divalent cations or under heat shock. In addition to dimers, oligomers exhibit a chaperone activity. In this work, we focused on Mg(2+)-induced oligomers that we named Type I, Type II, and Type III in increasing molecular mass order. After stabilization of these quaternary structures, we optimized a purification protocol. Combining analytical ultracentrifugation, size exclusion chromatography coupled to multiangle laser light scattering, and high mass matrix-assisted laser desorption/ionization time of flight mass spectrometry, we determined biochemical and biophysical characteristics of each Hsp90 oligomer. We demonstrate that Type I oligomer is a tetramer, and Type II is an hexamer, whereas Type III is a dodecamer. These even-numbered structures demonstrate that the building brick for oligomerization is the dimer up to the Type II, whereas Type III probably results from the association of two Type II. Moreover, the Type II oligomer structure, studied by negative stain transmission electron microscopy tomography, exhibits a "nest-like" shape that forms a "cozy chaperoning chamber" where the client protein folding/protection could occur.
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Affiliation(s)
- Laura Moullintraffort
- Structure et Dynamique des Macromolecules, UMR-CNRS 6026, Université de Rennes 1, 35042 Rennes Cedex France
| | - Matthieu Bruneaux
- Equipe Ecophysiologie des Invertébrés Marins des Milieux Extrêmes, Université Pierre et Marie Curie Paris VI, CNRS UMR 7144, Station Biologique de Roscoff, B.P. 74, 29682 Roscoff, France
| | | | - Diane Allegro
- CRO2 UMR Inserm 911, Université de la Méditerranée, Faculté de Pharmacie, 13385 Marseille Cedex 5, France
| | - Emmanuel Giudice
- Structure et Dynamique des Macromolecules, UMR-CNRS 6026, Université de Rennes 1, 35042 Rennes Cedex France
| | - Franck Zal
- Equipe Ecophysiologie des Invertébrés Marins des Milieux Extrêmes, Université Pierre et Marie Curie Paris VI, CNRS UMR 7144, Station Biologique de Roscoff, B.P. 74, 29682 Roscoff, France
| | - Vincent Peyrot
- CRO2 UMR Inserm 911, Université de la Méditerranée, Faculté de Pharmacie, 13385 Marseille Cedex 5, France
| | | | - Daniel Thomas
- Structure et Dynamique des Macromolecules, UMR-CNRS 6026, Université de Rennes 1, 35042 Rennes Cedex France
| | - Cyrille Garnier
- Structure et Dynamique des Macromolecules, UMR-CNRS 6026, Université de Rennes 1, 35042 Rennes Cedex France.
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Weis F, Moullintraffort L, Heichette C, Chrétien D, Garnier C. The 90-kDa heat shock protein Hsp90 protects tubulin against thermal denaturation. J Biol Chem 2010; 285:9525-9534. [PMID: 20110359 DOI: 10.1074/jbc.m109.096586] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Hsp90 and tubulin are among the most abundant proteins in the cytosol of eukaryotic cells. Although Hsp90 plays key roles in maintaining its client proteins in their active state, tubulin is essential for fundamental processes such as cell morphogenesis and division. Several studies have suggested a possible connection between Hsp90 and the microtubule cytoskeleton. Because tubulin is a labile protein in its soluble form, we investigated whether Hsp90 protects it against thermal denaturation. Both proteins were purified from porcine brain, and their interaction was characterized in vitro by using spectrophotometry, sedimentation assays, video-enhanced differential interference contrast light microscopy, and native polyacrylamide gel electrophoresis. Our results show that Hsp90 protects tubulin against thermal denaturation and keeps it in a state compatible with microtubule polymerization. We demonstrate that Hsp90 cannot resolve tubulin aggregates but that it likely binds early unfolding intermediates, preventing their aggregation. Protection was maximal at a stoichiometry of two molecules of Hsp90 for one of tubulin. This protection does not require ATP binding and hydrolysis by Hsp90, but it is counteracted by geldanamycin, a specific inhibitor of Hsp90.
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Affiliation(s)
- Felix Weis
- UMR-CNRS 6026, IFR 140-Génétique Fonctionnelle Agronomie et Santé, "Interactions Cellulaires et Moléculaires," Université de Rennes 1, Campus de Beaulieu, Bâtiment 13, 263 Avenue du Général Leclerc, 35042 Rennes, France
| | - Laura Moullintraffort
- UMR-CNRS 6026, IFR 140-Génétique Fonctionnelle Agronomie et Santé, "Interactions Cellulaires et Moléculaires," Université de Rennes 1, Campus de Beaulieu, Bâtiment 13, 263 Avenue du Général Leclerc, 35042 Rennes, France
| | - Claire Heichette
- UMR-CNRS 6026, IFR 140-Génétique Fonctionnelle Agronomie et Santé, "Interactions Cellulaires et Moléculaires," Université de Rennes 1, Campus de Beaulieu, Bâtiment 13, 263 Avenue du Général Leclerc, 35042 Rennes, France
| | - Denis Chrétien
- UMR-CNRS 6026, IFR 140-Génétique Fonctionnelle Agronomie et Santé, "Interactions Cellulaires et Moléculaires," Université de Rennes 1, Campus de Beaulieu, Bâtiment 13, 263 Avenue du Général Leclerc, 35042 Rennes, France
| | - Cyrille Garnier
- UMR-CNRS 6026, IFR 140-Génétique Fonctionnelle Agronomie et Santé, "Interactions Cellulaires et Moléculaires," Université de Rennes 1, Campus de Beaulieu, Bâtiment 13, 263 Avenue du Général Leclerc, 35042 Rennes, France.
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Devred F, Barbier P, Lafitte D, Landrieu I, Lippens G, Peyrot V. Microtubule and MAPs: thermodynamics of complex formation by AUC, ITC, fluorescence, and NMR. Methods Cell Biol 2010; 95:449-80. [PMID: 20466148 DOI: 10.1016/s0091-679x(10)95023-1] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Microtubules are implicated in many essential cellular processes such as architecture, cell division, and intracellular traffic, due to their dynamic instability. This dynamicity is tightly regulated by microtubule-associated proteins (MAPs), such as tau and stathmin. Despite extensive studies motivated by their central role in physiological functions and pathological role in neurodegenerative diseases and cancer, the precise mechanisms of tau and stathmin binding to tubulin and their consequences on microtubule stability are still not fully understood. One of the most crucial points missing is a quantitative thermodynamic description of their interaction with tubulin/microtubules and of the tubulin complexes formed upon these interactions. In this chapter, we will focus on the use of analytical ultracentrifugation, isothermal titration calorimetry, and nuclear magnetic resonance-three powerful and complementary techniques in the field of MAP-tubulin/microtubule interactions, in addition to the spectrometric techniques and co-sedimentation approach. We will present the limits of these techniques to study this particular interaction and precautions that need to be taken during MAPs preparation. Understanding the molecular mechanisms that govern MAPs action on microtubular network will not only shed new light on the role of this crucial family of protein in the biology of the cell, but also hopefully open new paths to increase the therapeutic efficiency of microtubule-targeting drugs in cancers therapies and neurodegeneratives diseases prevention.
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Affiliation(s)
- François Devred
- CRO2, U911 Inserm, Aix-Marseille Université, 27 Bd Jean Moulin, 13385 Marseille cedex 05, France
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Kwon HY, Kim EH, Tran TDH, Pyo SN, Rhee DK. Reduction-sensitive and cysteine residue-mediated Streptococcus pneumoniae HrcA oligomerization in vitro. Mol Cells 2009; 27:149-57. [PMID: 19277496 DOI: 10.1007/s10059-009-0019-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2008] [Revised: 10/31/2008] [Accepted: 11/19/2008] [Indexed: 01/16/2023] Open
Abstract
In both gram-positive and several gram-negative bacteria, the transcription of dnaK and groE operons is negatively regulated by HrcA; however, the mechanism modulating HrcA protein activity upon thermal stress remains elusive. Here, we demonstrate that HrcA is modulated via reduction and oligomerization in vitro. Native-PAGE analysis was used to reveal the oligomeric structure of HrcA. The oligomeric HrcA structure became monomeric following treatment with the reducing agent dithothreitol, and this process was reversed by treatment with hydrogen peroxide. Moreover, the mutant HrcA C118S exhibited reduced binding to CIRCE elements and became less oligomerized, suggesting that cysteine residue 118 is important for CIRCE element binding as well as oligomerization. Conversely, HrcA mutant C280S exhibited increased oligomerization. An HrcA double mutant (C118S, C280S) was monomeric and exhibited a level of oligomerization and CIRCE binding similar to wild type HrcA, suggesting that cysteine residues 118 and 280 may function as checks to one another during oligomer formation. Biochemical fractionation of E. coli cells overexpressing HrcA revealed the presence of HrcA in the membrane fraction. Together, these results suggest that the two HrcA cysteine residues at positions 118 and 280 function as reduction sensors in the membrane and mediate oligomerization upon stress.
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Affiliation(s)
- Hyog-Young Kwon
- College of Pharmacy, Sungkyunkwan University, Suwon, 440-746, Korea
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18
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Abstract
BACKGROUND INFORMATION Hsp90 (90 kDa heat-shock protein) plays a key role in the folding and activation of many client proteins involved in signal transduction and cell cycle control. The cycle of Hsp90 has been intimately associated with large conformational rearrangements, which are nucleotide-binding-dependent. However, up to now, our understanding of Hsp90 conformational changes derives from structural information, which refers to the crystal states of either recombinant Hsp90 constructs or the prokaryotic homologue HtpG (Hsp90 prokaryotic homologue). RESULTS AND DISCUSSION Here, we present the first nucleotide-free structures of the entire eukaryotic Hsp90 (apo-Hsp90) obtained by small-angle X-ray scattering and single-particle cryo-EM (cryo-electron microscopy). We show that, in solution, apo-Hsp90 is in a conformational equilibrium between two open states that have never been described previously. By comparing our cryo-EM maps with HtpG and known Hsp90 structures, we establish that the structural changes involved in switching between the two Hsp90 apo-forms require large movements of the NTD (N-terminal domain) and MD (middle domain) around two flexible hinge regions. CONCLUSIONS The present study shows, for the first time, the structure of the entire eukaryotic apo-Hsp90, along with its intrinsic flexibility. Although large structural rearrangements, leading to partial closure of the Hsp90 dimer, were previously attributed to the binding of nucleotides, our results reveal that they are in fact mainly due to the intrinsic flexibility of Hsp90 dimer. Taking into account the preponderant role of the dynamic nature of the structure of Hsp90, we reconsider the Hsp90 ATPase cycle.
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Abstract
Hydrodynamic bead modeling (HBM) is the representation of a macromolecule by an assembly of spheres (or beads) for which measurable hydrodynamic (and related) parameters are then computed in order to understand better the macromolecular solution conformation. An example-based account is given of the main stages in HBM of rigid macromolecules, namely: model construction, model visualization, accounting for hydration, and hydrodynamic calculations. Different types of models are appropriate for different macromolecules, according to their composition, to what is known about the molecule or according to the types of experimental data that the model should reproduce. Accordingly, the construction of models based on atomic coordinates as well as much lower resolution data (e.g., electron microscopy images) is described. Similarly, several programs for hydrodynamic calculations are summarized, some generating the most basic set of solution parameters (e.g., sedimentation and translational diffusion coefficients, intrinsic viscosity, radius of gyration, and Stokes radius) while others extend to data determined by nuclear magnetic resonance, fluorescence anisotropy, and electric birefringence methods. An insight into the topic of hydrodynamic hydration is given, together with some practical suggestions for its satisfactory treatment in the modeling context. All programs reviewed are freely available.
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20
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Squier TC. Redox modulation of cellular metabolism through targeted degradation of signaling proteins by the proteasome. Antioxid Redox Signal 2006; 8:217-28. [PMID: 16487055 DOI: 10.1089/ars.2006.8.217] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Under conditions of oxidative stress, the 20S proteasome plays a critical role in maintaining cellular homeostasis through the selective degradation of oxidized and damaged proteins. This adaptive stress response is distinct from ubiquitin-dependent pathways in that oxidized proteins are recognized and degraded in an ATP-independent mechanism, which can involve the molecular chaperone Hsp90. Like the regulatory complexes 19S and 11S REG, Hsp90 tightly associates with the 20S proteasome to mediate the recognition of aberrant proteins for degradation. In the case of the calcium signaling protein calmodulin, proteasomal degradation results from the oxidation of a single surface exposed methionine (i.e., Met145); oxidation of the other eight methionines has a minimal effect on the recognition and degradation of calmodulin by the proteasome. Since cellular concentrations of calmodulin are limiting, the targeted degradation of this critical signaling protein under conditions of oxidative stress will result in the downregulation of cellular metabolism, serving as a feedback regulation to diminish the generation of reactive oxygen species. The targeted degradation of critical signaling proteins, such as calmodulin, can function as sensors of oxidative stress to downregulate global rates of metabolism and enhance cellular survival.
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Affiliation(s)
- Thomas C Squier
- Cell Biology and Biochemistry Group, Biological Sciences Division, Pacific Northwest National Laboratory, Richland, Washington, USA.
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Whittier JE, Xiong Y, Rechsteiner MC, Squier TC. Hsp90 enhances degradation of oxidized calmodulin by the 20 S proteasome. J Biol Chem 2004; 279:46135-42. [PMID: 15319444 DOI: 10.1074/jbc.m406048200] [Citation(s) in RCA: 76] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The 20 S proteasome has been suggested to play a critical role in mediating the degradation of abnormal proteins under conditions of oxidative stress and has been found in tight association with the molecular chaperone Hsp90. To elucidate the role of Hsp90 in promoting the degradation of oxidized calmodulin (CaM(ox)), we have purified red blood cell 20 S proteasomes free of Hsp90 and assessed their ability to degrade CaM(ox) in the absence or presence of Hsp90. Purified 20 S proteasome does not degrade CaM(ox) unless Hsp90 is added. CaM(ox) degradation is sensitive to both proteasome and Hsp90-specific inhibitors and is further enhanced in the presence of 2 mm ATP. Irrespective of the presence of Hsp90, we find that unoxidized CaM is not significantly degraded. Direct binding measurements demonstrate that Hsp90 selectively associates with CaM(ox); essentially no binding is observed between Hsp90 and unoxidized CaM. These results indicate that Hsp90 in association with the 20 S proteasome can selectively associate with oxidized and partially unfolded CaM to promote degradation by the proteasome.
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Affiliation(s)
- Jennifer E Whittier
- Cell Biology and Biochemistry Group, Biological Sciences Division, Pacific Northwest National Laboratory, Richland, Washington 99352, USA
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