1
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Mawla GD, Kamal SM, Cao LY, Purhonen P, Hebert H, Sauer RT, Baker TA, Römling U. The membrane-cytoplasmic linker defines activity of FtsH proteases in Pseudomonas aeruginosa clone C. J Biol Chem 2024; 300:105622. [PMID: 38176647 PMCID: PMC10850787 DOI: 10.1016/j.jbc.2023.105622] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2023] [Revised: 12/22/2023] [Accepted: 12/27/2023] [Indexed: 01/06/2024] Open
Abstract
Pandemic Pseudomonas aeruginosa clone C strains encode two inner-membrane associated ATP-dependent FtsH proteases. PaftsH1 is located on the core genome and supports cell growth and intrinsic antibiotic resistance, whereas PaftsH2, a xenolog acquired through horizontal gene transfer from a distantly related species, is unable to functionally replace PaftsH1. We show that purified PaFtsH2 degrades fewer substrates than PaFtsH1. Replacing the 31-amino acid-extended linker region of PaFtsH2 spanning from the C-terminal end of the transmembrane helix-2 to the first seven highly divergent residues of the cytosolic AAA+ ATPase module with the corresponding region of PaFtsH1 improves hybrid-enzyme substrate processing in vitro and enables PaFtsH2 to substitute for PaFtsH1 in vivo. Electron microscopy indicates that the identity of this linker sequence influences FtsH flexibility. We find membrane-cytoplasmic (MC) linker regions of PaFtsH1 characteristically glycine-rich compared to those from FtsH2. Consequently, introducing three glycines into the membrane-proximal end of PaFtsH2's MC linker is sufficient to elevate its activity in vitro and in vivo. Our findings establish that the efficiency of substrate processing by the two PaFtsH isoforms depends on MC linker identity and suggest that greater linker flexibility and/or length allows FtsH to degrade a wider spectrum of substrates. As PaFtsH2 homologs occur across bacterial phyla, we hypothesize that FtsH2 is a latent enzyme but may recognize specific substrates or is activated in specific contexts or biological niches. The identity of such linkers might thus play a more determinative role in the functionality of and physiological impact by FtsH proteases than previously thought.
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Affiliation(s)
- Gina D Mawla
- Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
| | - Shady M Kamal
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm; Sweden
| | - Lian-Ying Cao
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm; Sweden
| | - Pasi Purhonen
- Department of Biomedical Engineering and Health Systems, KTH Royal Institute of Technology, Huddinge; Sweden
| | - Hans Hebert
- Department of Biomedical Engineering and Health Systems, KTH Royal Institute of Technology, Huddinge; Sweden
| | - Robert T Sauer
- Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA
| | - Tania A Baker
- Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA.
| | - Ute Römling
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm; Sweden.
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2
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Moon S, Ham S, Jeong J, Ku H, Kim H, Lee C. Temperature Matters: Bacterial Response to Temperature Change. J Microbiol 2023; 61:343-357. [PMID: 37010795 DOI: 10.1007/s12275-023-00031-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2023] [Revised: 02/13/2023] [Accepted: 02/13/2023] [Indexed: 04/04/2023]
Abstract
Temperature is one of the most important factors in all living organisms for survival. Being a unicellular organism, bacterium requires sensitive sensing and defense mechanisms to tolerate changes in temperature. During a temperature shift, the structure and composition of various cellular molecules including nucleic acids, proteins, and membranes are affected. In addition, numerous genes are induced during heat or cold shocks to overcome the cellular stresses, which are known as heat- and cold-shock proteins. In this review, we describe the cellular phenomena that occur with temperature change and bacterial responses from a molecular perspective, mainly in Escherichia coli.
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Affiliation(s)
- Seongjoon Moon
- Department of Biological Sciences, Ajou University, Suwon, 16499, Republic of Korea
| | - Soojeong Ham
- Department of Biological Sciences, Ajou University, Suwon, 16499, Republic of Korea
| | - Juwon Jeong
- Department of Biological Sciences, Ajou University, Suwon, 16499, Republic of Korea
| | - Heechan Ku
- Department of Biological Sciences, Ajou University, Suwon, 16499, Republic of Korea
| | - Hyunhee Kim
- Department of Biological Sciences, Ajou University, Suwon, 16499, Republic of Korea.
| | - Changhan Lee
- Department of Biological Sciences, Ajou University, Suwon, 16499, Republic of Korea.
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3
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Giudice E, Georgeault S, Lavigne R, Pineau C, Trautwetter A, Ermel G, Blanco C, Gillet R. Purification and Characterization of Authentic 30S Ribosomal Precursors Induced by Heat Shock. Int J Mol Sci 2023; 24:ijms24043491. [PMID: 36834906 PMCID: PMC9959188 DOI: 10.3390/ijms24043491] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2022] [Revised: 02/02/2023] [Accepted: 02/06/2023] [Indexed: 02/12/2023] Open
Abstract
Ribosome biogenesis is a complex and multistep process that depends on various assembly factors. To understand this process and identify the ribosome assembly intermediates, most studies have set out to delete or deplete these assembly factors. Instead, we took advantage of the impact of heat stress (45 °C) on the late stages of the biogenesis of the 30S ribosomal subunit to explore authentic precursors. Under these conditions, reduced levels of the DnaK chaperone proteins devoted to ribosome assembly lead to the transient accumulation of 21S ribosomal particles, which are 30S precursors. We constructed strains with different affinity tags on one early and one late 30S ribosomal protein and purified the 21S particles that form under heat shock. A combination of relative quantification using mass spectrometry-based proteomics and cryo-electron microscopy (cryo-EM) was then used to determine their protein contents and structures.
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Affiliation(s)
- Emmanuel Giudice
- Univ Rennes, CNRS, Institut de Génétique et Développement de Rennes (IGDR) UMR6290, 35000 Rennes, France
| | - Sylvie Georgeault
- Univ Rennes, CNRS, Institut de Génétique et Développement de Rennes (IGDR) UMR6290, 35000 Rennes, France
| | - Régis Lavigne
- Univ Rennes, Inserm, EHESP, Irset (Institut de Recherche en Santé, Environnement et Travail)-UMR_S 1085, 35000 Rennes, France
- Univ Rennes, CNRS, Inserm, Biosit UAR 3480 US_S 018, Protim Core Facility, 35000 Rennes, France
| | - Charles Pineau
- Univ Rennes, Inserm, EHESP, Irset (Institut de Recherche en Santé, Environnement et Travail)-UMR_S 1085, 35000 Rennes, France
- Univ Rennes, CNRS, Inserm, Biosit UAR 3480 US_S 018, Protim Core Facility, 35000 Rennes, France
| | - Annie Trautwetter
- Univ Rennes, CNRS, Institut de Génétique et Développement de Rennes (IGDR) UMR6290, 35000 Rennes, France
| | - Gwennola Ermel
- Univ Rennes, CNRS, Institut de Génétique et Développement de Rennes (IGDR) UMR6290, 35000 Rennes, France
| | - Carlos Blanco
- Univ Rennes, CNRS, Institut de Génétique et Développement de Rennes (IGDR) UMR6290, 35000 Rennes, France
| | - Reynald Gillet
- Univ Rennes, CNRS, Institut de Génétique et Développement de Rennes (IGDR) UMR6290, 35000 Rennes, France
- Correspondence:
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4
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Woo J, Guk JH, Yi S, Lee J, Song H, Kim WH, Cho S. Effect of biofilm formation by antimicrobial-resistant gram-negative bacteria in cold storage on survival in dairy processing lines. Int J Food Microbiol 2023; 386:110019. [PMID: 36436412 DOI: 10.1016/j.ijfoodmicro.2022.110019] [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: 07/08/2022] [Revised: 10/22/2022] [Accepted: 11/13/2022] [Indexed: 11/20/2022]
Abstract
Antimicrobial-resistant gram-negative bacteria in dairy products can transfer antimicrobial resistance to gut microbiota in humans and can adversely impact the product quality. In this study, we aimed to investigate their distribution in dairy processing lines and evaluate biofilm formation and heat tolerance under dairy processing line-like conditions. Additionally, we compared the relative expression of general and heat stress-related genes as well as spoilage-related gene between biofilm and planktonic cells under consecutive stresses, similar to those in dairy processing lines. Most species of gram-negative bacteria isolated from five different dairy processing plants were resistant to one or more antimicrobials. Biofilm formation by the bacteria at 5 °C increased with the increase in exposure time. Moreover, cells in biofilms remained viable under heat treatment, whereas all planktonic cells of the selected strains died. The expression of heat-shock-related genes significantly increased with heat treatment in the biofilms but mostly decreased in the planktonic cells. Thus, biofilm formation under raw milk storage conditions may improve the tolerance of antimicrobial-resistant gram-negative bacteria to pasteurization, thereby increasing their persistence in dairy processing lines and products. Furthermore, the difference in response to heat stress between biofilm and planktonic cells may be attributed to the differential expression of heat stress-related genes. Therefore, this study contributes to the understanding of how gram-negative bacteria persist under consecutive stresses in dairy processing procedures and the potential mechanism underlying heat tolerance in biofilms.
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Affiliation(s)
- JungHa Woo
- College of Veterinary Medicine and Research Institute for Veterinary Science, Seoul National University, Seoul 08826, South Korea
| | - Jae-Ho Guk
- College of Veterinary Medicine and Research Institute for Veterinary Science, Seoul National University, Seoul 08826, South Korea
| | - Saehah Yi
- College of Veterinary Medicine and Research Institute for Veterinary Science, Seoul National University, Seoul 08826, South Korea
| | - Junbum Lee
- College of Veterinary Medicine and Research Institute for Veterinary Science, Seoul National University, Seoul 08826, South Korea
| | - Hyokeun Song
- College of Veterinary Medicine and Research Institute for Veterinary Science, Seoul National University, Seoul 08826, South Korea
| | - Woo-Hyun Kim
- College of Veterinary Medicine and Research Institute for Veterinary Science, Seoul National University, Seoul 08826, South Korea
| | - Seongbeom Cho
- College of Veterinary Medicine and Research Institute for Veterinary Science, Seoul National University, Seoul 08826, South Korea.
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5
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Lessons Learned from Two Decades of Modeling the Heat-Shock Response. Biomolecules 2022; 12:biom12111645. [DOI: 10.3390/biom12111645] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2022] [Revised: 10/18/2022] [Accepted: 10/25/2022] [Indexed: 11/09/2022] Open
Abstract
The Heat Shock Response (HSR) is a highly conserved genetic system charged with protecting the proteome in a wide range of organisms and species. Experiments since the early 1980s have elucidated key elements in these pathways and revealed a canonical mode of regulation, which relies on a titration feedback. This system has been subject to substantial modeling work, addressing questions about resilience, design and control. The compact core regulatory circuit, as well as its apparent conservation, make this system an ideal ‘hydrogen atom’ model for the regulation of stress response. Here we take a broad view of the models of the HSR, focusing on the different questions asked and the approaches taken. After 20 years of modeling work, we ask what lessons had been learned that would have been hard to discover without mathematical models. We find that while existing models lay strong foundations, many important questions that can benefit from quantitative modeling are still awaiting investigation.
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6
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The Role of Hsp70s in the Development and Pathogenicity of Plasmodium falciparum. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2021. [PMID: 34569021 DOI: 10.1007/978-3-030-78397-6_3] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/24/2024]
Abstract
The main agent of human malaria, the protozoa, Plasmodium falciparum is known to infect liver cells, subsequently invading the host erythrocyte, leading to the manifestation of clinical outcomes of the disease. As part of its survival in the human host, P. falciparum employs several heat shock protein (Hsp) families whose primary purpose is to ensure cytoprotection through their molecular chaperone role. The parasite expresses six Hsp70s that localise to various subcellular organelles of the parasite, with one, PfHsp70-x, being exported to the infected human erythrocyte. The role of these Hsp70s in the survival and pathogenicity of malaria has received immense research attention. Several studies have reported on their structure-function features, network partnerships, and elucidation of their potential substrates. Apart from their role in cytoprotection and pathogenicity, Hsp70s are implicated in antimalarial drug resistance. As such, they are deemed potential antimalarial drug candidates, especially suited for co-targeting in combination therapies. In addition, Hsp70 is implicated in host immune modulation. The current report highlights the various structure-function features of these proteins, their roles in the development of malaria, current and prospective efforts being employed towards targeting them in malaria intervention efforts.
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7
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Zavilgelsky GB, Gnuchikh EY, Melkina OE. Thermostability and Refolding of Proteins in Bacteria Is Determined by the Activity of Two Different ATP-Dependent Chaperone Groups. Mol Biol 2020. [DOI: 10.1134/s0026893320020193] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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8
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Anggarini S, Murata M, Kido K, Kosaka T, Sootsuwan K, Thanonkeo P, Yamada M. Improvement of Thermotolerance of Zymomonas mobilis by Genes for Reactive Oxygen Species-Scavenging Enzymes and Heat Shock Proteins. Front Microbiol 2020; 10:3073. [PMID: 32082264 PMCID: PMC7002363 DOI: 10.3389/fmicb.2019.03073] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2019] [Accepted: 12/19/2019] [Indexed: 02/06/2023] Open
Abstract
Thermotolerant genes, which are essential for survival at a high temperature, have been identified in three mesophilic microbes, including Zymomonas mobilis. Contrary to expectation, they include only a few genes for reactive oxygen species (ROS)-scavenging enzymes and heat shock proteins, which are assumed to play key roles at a critical high temperature (CHT) as an upper limit of survival. We thus examined the effects of increased expression of these genes on the cell growth of Z. mobilis strains at its CHT. When overexpressed, most of the genes increased the CHT by about one degree, and some of them enhanced tolerance against acetic acid. These findings suggest that ROS-damaged molecules or unfolded proteins that prevent cell growth are accumulated in cells at the CHT.
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Affiliation(s)
- Sakunda Anggarini
- Division of Life Science, Graduate School of Sciences and Technology for Innovation, Yamaguchi University, Ube, Japan
| | - Masayuki Murata
- Division of Life Science, Graduate School of Sciences and Technology for Innovation, Yamaguchi University, Ube, Japan
| | - Keisuke Kido
- Department of Biological Chemistry, Faculty of Agriculture, Yamaguchi University, Yamaguchi, Japan
| | - Tomoyuki Kosaka
- Division of Life Science, Graduate School of Sciences and Technology for Innovation, Yamaguchi University, Ube, Japan.,Department of Biological Chemistry, Faculty of Agriculture, Yamaguchi University, Yamaguchi, Japan.,Research Center for Thermotolerant Microbial Resources, Yamaguchi University, Yamaguchi, Japan
| | - Kaewta Sootsuwan
- Faculty of Agro-Industrial Technology, Rajamangala University of Technology Isan, Kalasin, Thailand
| | - Pornthap Thanonkeo
- Department of Biotechnology, Faculty of Technology, Khon Kaen University, Khon Kaen, Thailand
| | - Mamoru Yamada
- Division of Life Science, Graduate School of Sciences and Technology for Innovation, Yamaguchi University, Ube, Japan.,Department of Biological Chemistry, Faculty of Agriculture, Yamaguchi University, Yamaguchi, Japan.,Research Center for Thermotolerant Microbial Resources, Yamaguchi University, Yamaguchi, Japan
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9
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Amin-Wetzel N, Neidhardt L, Yan Y, Mayer MP, Ron D. Unstructured regions in IRE1α specify BiP-mediated destabilisation of the luminal domain dimer and repression of the UPR. eLife 2019; 8:50793. [PMID: 31873072 PMCID: PMC6996924 DOI: 10.7554/elife.50793] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2019] [Accepted: 12/23/2019] [Indexed: 12/15/2022] Open
Abstract
Coupling of endoplasmic reticulum (ER) stress to dimerisation-dependent activation of the UPR transducer IRE1 is incompletely understood. Whilst the luminal co-chaperone ERdj4 promotes a complex between the Hsp70 BiP and IRE1's stress-sensing luminal domain (IRE1LD) that favours the latter's monomeric inactive state and loss of ERdj4 de-represses IRE1, evidence linking these cellular and in vitro observations is presently lacking. We report that enforced loading of endogenous BiP onto endogenous IRE1α repressed UPR signalling in CHO cells and deletions in the IRE1α locus that de-repressed the UPR in cells, encode flexible regions of IRE1LD that mediated BiP-induced monomerisation in vitro. Changes in the hydrogen exchange mass spectrometry profile of IRE1LD induced by ERdj4 and BiP confirmed monomerisation and were consistent with active destabilisation of the IRE1LD dimer. Together, these observations support a competition model whereby waning ER stress passively partitions ERdj4 and BiP to IRE1LD to initiate active repression of UPR signalling.
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Affiliation(s)
- Niko Amin-Wetzel
- Cambridge Institute for Medical Research (CIMR), University of Cambridge, Cambridge, United Kingdom
| | - Lisa Neidhardt
- Cambridge Institute for Medical Research (CIMR), University of Cambridge, Cambridge, United Kingdom
| | - Yahui Yan
- Cambridge Institute for Medical Research (CIMR), University of Cambridge, Cambridge, United Kingdom
| | - Matthias P Mayer
- Center for Molecular Biology of Heidelberg University (ZMBH), DKFZ-ZMBH Alliance, Heidelberg, Germany
| | - David Ron
- Cambridge Institute for Medical Research (CIMR), University of Cambridge, Cambridge, United Kingdom
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10
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Saltepe B, Bozkurt EU, Hacıosmanoğlu N, Şeker UÖŞ. Genetic Circuits To Detect Nanomaterial Triggered Toxicity through Engineered Heat Shock Response Mechanism. ACS Synth Biol 2019; 8:2404-2417. [PMID: 31536326 DOI: 10.1021/acssynbio.9b00291] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Biocompatibility assessment of nanomaterials has been of great interest due to their potential toxicity. However, conventional biocompatibility tests fall short of providing a fast toxicity report. We developed a whole cell based biosensor to track biocompatibility of nanomaterials with the aim of providing fast feedback to engineer them with lower toxicity levels. We engineered promoters of four heat shock response (HSR) proteins utilizing synthetic biology approaches. As an initial design, a reporter coding gene was cloned downstream of the selected promoter regions. Initial results indicated that native heat shock protein (HSP) promoter regions were not very promising to generate signals with low background signals. Introducing riboregulators to native promoters eliminated unwanted background signals almost entirely. Yet, this approach also led to a decrease in expected sensor signal upon stress treatment. Thus, a repression based genetic circuit, inspired by the HSR mechanism of Mycobacterium tuberculosis, was constructed. These genetic circuits could report the toxicity of quantum dot nanoparticles in 1 h. Our designed nanoparticle toxicity sensors can provide quick reports, which can lower the demand for additional experiments with more complex organisms.
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Affiliation(s)
- Behide Saltepe
- UNAM−Institute of Materials Science and Nanotechnology, National Nanotechnology Research Center, Bilkent University, 06800 Ankara, Turkey
- Institute of Materials Science and Nanotechnology, Bilkent University, 06800 Ankara, Turkey
| | - Eray Ulaş Bozkurt
- UNAM−Institute of Materials Science and Nanotechnology, National Nanotechnology Research Center, Bilkent University, 06800 Ankara, Turkey
- Institute of Materials Science and Nanotechnology, Bilkent University, 06800 Ankara, Turkey
| | - Nedim Hacıosmanoğlu
- UNAM−Institute of Materials Science and Nanotechnology, National Nanotechnology Research Center, Bilkent University, 06800 Ankara, Turkey
- Institute of Materials Science and Nanotechnology, Bilkent University, 06800 Ankara, Turkey
| | - Urartu Özgür Şafak Şeker
- UNAM−Institute of Materials Science and Nanotechnology, National Nanotechnology Research Center, Bilkent University, 06800 Ankara, Turkey
- Institute of Materials Science and Nanotechnology, Bilkent University, 06800 Ankara, Turkey
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11
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Preissler S, Ron D. Early Events in the Endoplasmic Reticulum Unfolded Protein Response. Cold Spring Harb Perspect Biol 2019; 11:cshperspect.a033894. [PMID: 30396883 PMCID: PMC6442202 DOI: 10.1101/cshperspect.a033894] [Citation(s) in RCA: 104] [Impact Index Per Article: 20.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
The physiological consequences of the unfolded protein response (UPR) are mediated by changes in gene expression. Underlying them are rapid processes involving preexisting components. We review recent insights gained into the regulation of the endoplasmic reticulum (ER) Hsp70 chaperone BiP, whose incorporation into inactive oligomers and reversible AMPylation and de-AMPylation present a first line of response to fluctuating levels of unfolded proteins. BiP activity is tied to the regulation of the UPR transducers by a recently discovered cycle of ER-localized, J protein-mediated formation of a repressive IRE1-BiP complex, whose working we contrast to an alternative model for UPR regulation that relies on direct recognition of unfolded proteins. We conclude with a discussion of mechanisms that repress messenger RNA (mRNA) translation to limit the flux of newly synthesized proteins into the ER, a rapid adaptation that does not rely on new macromolecule biosynthesis.
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12
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13
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Yura T, Miyazaki R, Fujiwara K, Ito K, Chiba S, Mori H, Akiyama Y. Heat shock transcription factor σ<sup>32</sup> defective in membrane transport can be suppressed by transposon insertion into genes encoding a restriction enzyme subunit or a putative autotransporter in <i>Escherichia coli</i>. Genes Genet Syst 2018; 93:229-235. [DOI: 10.1266/ggs.18-00040] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Affiliation(s)
- Takashi Yura
- Faculty of Life Sciences, Kyoto Sangyo University
| | - Ryoji Miyazaki
- Institute for Frontier Life and Medical Sciences, Kyoto University
| | | | - Koreaki Ito
- Faculty of Life Sciences, Kyoto Sangyo University
| | | | - Hiroyuki Mori
- Institute for Frontier Life and Medical Sciences, Kyoto University
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14
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Biran D, Rotem O, Rosen R, Ron EZ. Coping with High Temperature: A Unique Regulation in A. tumefaciens. Curr Top Microbiol Immunol 2018; 418:185-194. [PMID: 30182196 DOI: 10.1007/82_2018_119] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Elevation of temperature is a frequent and considerable stress for mesophilic bacteria. Therefore, several molecular mechanisms have evolved to cope with high temperature. We have been studying the response of Agrobacterium tumefaciens to temperature stress, focusing on two aspects: the heat-shock response and the temperature-dependent regulation of methionine biosynthesis. The results indicate that the molecular mechanisms involved in A. tumefaciens control of growth at high temperature are unique and we are still missing important information essential for understanding how these bacteria cope with temperature stress.
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Affiliation(s)
- Dvora Biran
- School of Molecular Cell Biology and Biotechnology, Faculty of Life Sciences, Tel Aviv University, 69978, Tel Aviv, Israel
| | - Or Rotem
- School of Molecular Cell Biology and Biotechnology, Faculty of Life Sciences, Tel Aviv University, 69978, Tel Aviv, Israel
| | - Ran Rosen
- School of Molecular Cell Biology and Biotechnology, Faculty of Life Sciences, Tel Aviv University, 69978, Tel Aviv, Israel
| | - Eliora Z Ron
- School of Molecular Cell Biology and Biotechnology, Faculty of Life Sciences, Tel Aviv University, 69978, Tel Aviv, Israel.
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15
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Schramm FD, Heinrich K, Thüring M, Bernhardt J, Jonas K. An essential regulatory function of the DnaK chaperone dictates the decision between proliferation and maintenance in Caulobacter crescentus. PLoS Genet 2017; 13:e1007148. [PMID: 29281627 PMCID: PMC5760092 DOI: 10.1371/journal.pgen.1007148] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2017] [Revised: 01/09/2018] [Accepted: 12/11/2017] [Indexed: 11/19/2022] Open
Abstract
Hsp70 chaperones are well known for their important functions in maintaining protein homeostasis during thermal stress conditions. In many bacteria the Hsp70 homolog DnaK is also required for growth in the absence of stress. The molecular reasons underlying Hsp70 essentiality remain in most cases unclear. Here, we demonstrate that DnaK is essential in the α-proteobacterium Caulobacter crescentus due to its regulatory function in gene expression. Using a suppressor screen we identified mutations that allow growth in the absence of DnaK. All mutations reduced the activity of the heat shock sigma factor σ32, demonstrating that the DnaK-dependent inactivation of σ32 is a growth requirement. While most mutations occurred in the rpoH gene encoding σ32, we also identified mutations affecting σ32 activity or stability in trans, providing important new insight into the regulatory mechanisms controlling σ32 activity. Most notably, we describe a mutation in the ATP dependent protease HslUV that induces rapid degradation of σ32, and a mutation leading to increased levels of the house keeping σ70 that outcompete σ32 for binding to the RNA polymerase. We demonstrate that σ32 inhibits growth and that its unrestrained activity leads to an extensive reprogramming of global gene expression, resulting in upregulation of repair and maintenance functions and downregulation of the growth-promoting functions of protein translation, DNA replication and certain metabolic processes. While this re-allocation from proliferative to maintenance functions could provide an advantage during heat stress, it leads to growth defects under favorable conditions. We conclude that Caulobacter has co-opted the DnaK chaperone system as an essential regulator of gene expression under conditions when its folding activity is dispensable. Molecular chaperones of the Hsp70 family belong to the most conserved cellular machineries throughout the tree of life. These proteins play key roles in maintaining protein homeostasis, especially under heat stress conditions. In diverse bacteria the Hsp70 homolog DnaK is essential for growth even in the absence of stress. However, the molecular mechanisms underlying the essential nature of DnaK have in most cases not been studied. We found in the α-proteobacterium Caulobacter crescentus that the function of DnaK as a folding catalyst is dispensable in the absence of stress. Instead, its sole essential function under such conditions is to inhibit the activity of the heat shock sigma factor σ32. Our findings highlight that some bacteria have co-opted chaperones as essential regulators of gene expression under conditions when their folding activity is not required. Furthermore, our work illustrates that essential genes can perform different essential functions in discrete growth conditions.
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Affiliation(s)
- Frederic D. Schramm
- Science for Life Laboratory, Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, Stockholm, Sweden
- LOEWE Center for Synthetic Microbiology (SYNMIKRO), Philipps University Marburg, Marburg, Germany
| | - Kristina Heinrich
- Science for Life Laboratory, Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, Stockholm, Sweden
- LOEWE Center for Synthetic Microbiology (SYNMIKRO), Philipps University Marburg, Marburg, Germany
| | - Marietta Thüring
- LOEWE Center for Synthetic Microbiology (SYNMIKRO), Philipps University Marburg, Marburg, Germany
| | - Jörg Bernhardt
- Institute of Microbiology, Ernst-Moritz-Arndt University Greifswald, Greifswald, Germany
| | - Kristina Jonas
- Science for Life Laboratory, Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, Stockholm, Sweden
- LOEWE Center for Synthetic Microbiology (SYNMIKRO), Philipps University Marburg, Marburg, Germany
- * E-mail:
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16
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Mitsui H, Minamisawa K. Expression of Two RpoH Sigma Factors in Sinorhizobium meliloti upon Heat Shock. Microbes Environ 2017; 32:394-397. [PMID: 29199214 PMCID: PMC5745026 DOI: 10.1264/jsme2.me17087] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
The plant symbiotic α-proteobacterium Sinorhizobium meliloti has two RpoH-type sigma factors, RpoH1 and RpoH2. The former induces the synthesis of heat shock proteins and optimizes interactions with the host. Using a Western blot analysis, we examined time course changes in the intracellular contents of these factors upon a temperature upshift. The RpoH1 level was relatively high and constant, suggesting that its regulatory role in the heat shock response is attained through the activation of the pre-existing RpoH1 protein. In contrast, the RpoH2 level was initially undetectable, and gradually increased. These differential patterns reflect the functional diversification of these factors.
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17
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Amin-Wetzel N, Saunders RA, Kamphuis MJ, Rato C, Preissler S, Harding HP, Ron D. A J-Protein Co-chaperone Recruits BiP to Monomerize IRE1 and Repress the Unfolded Protein Response. Cell 2017; 171:1625-1637.e13. [PMID: 29198525 PMCID: PMC5733394 DOI: 10.1016/j.cell.2017.10.040] [Citation(s) in RCA: 151] [Impact Index Per Article: 21.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2017] [Revised: 10/04/2017] [Accepted: 10/25/2017] [Indexed: 12/29/2022]
Abstract
When unfolded proteins accumulate in the endoplasmic reticulum (ER), the unfolded protein response (UPR) increases ER-protein-folding capacity to restore protein-folding homeostasis. Unfolded proteins activate UPR signaling across the ER membrane to the nucleus by promoting oligomerization of IRE1, a conserved transmembrane ER stress receptor. However, the coupling of ER stress to IRE1 oligomerization and activation has remained obscure. Here, we report that the ER luminal co-chaperone ERdj4/DNAJB9 is a selective IRE1 repressor that promotes a complex between the luminal Hsp70 BiP and the luminal stress-sensing domain of IRE1α (IRE1LD). In vitro, ERdj4 is required for complex formation between BiP and IRE1LD. ERdj4 associates with IRE1LD and recruits BiP through the stimulation of ATP hydrolysis, forcibly disrupting IRE1 dimers. Unfolded proteins compete for BiP and restore IRE1LD to its default, dimeric, and active state. These observations establish BiP and its J domain co-chaperones as key regulators of the UPR. The endoplasmic reticulum co-chaperone ERdj4 selectively represses IRE1 signaling ERdj4 associates with the IRE1 luminal domain and recruits the Hsp70 BiP Recruited BiP hydrolyzes ATP to disrupt the active IRE1 luminal domain dimer Unfolded proteins compete for the repressive machinery to restore IRE1 dimers
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Affiliation(s)
- Niko Amin-Wetzel
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge CB2 0XY, UK
| | - Reuben A Saunders
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge CB2 0XY, UK
| | - Maarten J Kamphuis
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge CB2 0XY, UK
| | - Claudia Rato
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge CB2 0XY, UK
| | - Steffen Preissler
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge CB2 0XY, UK
| | - Heather P Harding
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge CB2 0XY, UK
| | - David Ron
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge CB2 0XY, UK.
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Morgan GJ, Burkhardt DH, Kelly JW, Powers ET. Translation efficiency is maintained at elevated temperature in Escherichia coli. J Biol Chem 2017; 293:777-793. [PMID: 29183994 DOI: 10.1074/jbc.ra117.000284] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2017] [Revised: 11/22/2017] [Indexed: 01/30/2023] Open
Abstract
Cellular protein levels are dictated by the balance between gene transcription, mRNA translation, and protein degradation, among other factors. Translation requires the interplay of several RNA hybridization processes, which are expected to be temperature-sensitive. We used ribosome profiling to monitor translation in Escherichia coli at 30 °C and to investigate how this changes after 10-20 min of heat shock at 42 °C. Translation efficiencies are robustly maintained after thermal heat shock and after mimicking the heat-shock response transcriptional program at 30 °C by overexpressing the heat shock σ factor encoded by the rpoH gene. We compared translation efficiency, the ratio of ribosome footprint reads to mRNA reads for each gene, to parameters derived from gene sequences. Genes with stable mRNA structures, non-optimal codon use, and those whose gene product is cotranslationally translocated into the inner membrane are generally less highly translated than other genes. Comparison with other published datasets suggests a role for translational elongation in coupling mRNA structures to translation initiation. Genome-wide calculations of the temperature dependence of mRNA structure predict that relatively few mRNAs show a melting transition between 30 and 42 °C, consistent with the observed lack of changes in translation efficiency. We developed a linear model with six parameters that can predict 38% of the variation in translation efficiency between genes, which may be useful in interpreting transcriptome data.
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Affiliation(s)
- Gareth J Morgan
- From the Departments of Chemistry and Molecular Medicine and
| | - David H Burkhardt
- California Institute of Quantitative Biosciences and Department of Microbiology and Immunology, University of California, San Francisco, San Francisco, California 94158
| | - Jeffery W Kelly
- From the Departments of Chemistry and Molecular Medicine and.,Skaggs Institute for Chemical Biology, The Scripps Research Institute, La, Jolla, California 92037, and
| | - Evan T Powers
- From the Departments of Chemistry and Molecular Medicine and
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Roncarati D, Scarlato V. Regulation of heat-shock genes in bacteria: from signal sensing to gene expression output. FEMS Microbiol Rev 2017; 41:549-574. [PMID: 28402413 DOI: 10.1093/femsre/fux015] [Citation(s) in RCA: 104] [Impact Index Per Article: 14.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2016] [Accepted: 03/14/2017] [Indexed: 02/07/2023] Open
Abstract
The heat-shock response is a mechanism of cellular protection against sudden adverse environmental growth conditions and results in the prompt production of various heat-shock proteins. In bacteria, specific sensory biomolecules sense temperature fluctuations and transduce intercellular signals that coordinate gene expression outputs. Sensory biomolecules, also known as thermosensors, include nucleic acids (DNA or RNA) and proteins. Once a stress signal is perceived, it is transduced to invoke specific molecular mechanisms controlling transcription of genes coding for heat-shock proteins. Transcriptional regulation of heat-shock genes can be under either positive or negative control mediated by dedicated regulatory proteins. Positive regulation exploits specific alternative sigma factors to redirect the RNA polymerase enzyme to a subset of selected promoters, while negative regulation is mediated by transcriptional repressors. Interestingly, while various bacteria adopt either exclusively positive or negative mechanisms, in some microorganisms these two opposite strategies coexist, establishing complex networks regulating heat-shock genes. Here, we comprehensively summarize molecular mechanisms that microorganisms have adopted to finely control transcription of heat-shock genes.
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Affiliation(s)
- Davide Roncarati
- Department of Pharmacy and Biotechnology (FaBiT), University of Bologna, 40126 Bologna, Italy
| | - Vincenzo Scarlato
- Department of Pharmacy and Biotechnology (FaBiT), University of Bologna, 40126 Bologna, Italy
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20
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Bittner LM, Arends J, Narberhaus F. When, how and why? Regulated proteolysis by the essential FtsH protease in Escherichia coli. Biol Chem 2017; 398:625-635. [PMID: 28085670 DOI: 10.1515/hsz-2016-0302] [Citation(s) in RCA: 60] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2016] [Accepted: 01/09/2017] [Indexed: 11/15/2022]
Abstract
Cellular proteomes are dynamic and adjusted to permanently changing conditions by ATP-fueled proteolytic machineries. Among the five AAA+ proteases in Escherichia coli FtsH is the only essential and membrane-anchored metalloprotease. FtsH is a homohexamer that uses its ATPase domain to unfold and translocate substrates that are subsequently degraded without the need of ATP in the proteolytic chamber of the protease domain. FtsH eliminates misfolded proteins in the context of general quality control and properly folded proteins for regulatory reasons. Recent trapping approaches have revealed a number of novel FtsH substrates. This review summarizes the substrate diversity of FtsH and presents details on the surprisingly diverse recognition principles of three well-characterized substrates: LpxC, the key enzyme of lipopolysaccharide biosynthesis; RpoH, the alternative heat-shock sigma factor and YfgM, a bifunctional membrane protein implicated in periplasmic chaperone functions and cytoplasmic stress adaptation.
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Affiliation(s)
- Lisa-Marie Bittner
- Microbial Biology, Ruhr University Bochum, Universitätsstr. 150, NDEF 06/783, D-44801 Bochum
| | - Jan Arends
- Microbial Biology, Ruhr University Bochum, Universitätsstr. 150, NDEF 06/783, D-44801 Bochum
| | - Franz Narberhaus
- Microbial Biology, Ruhr University Bochum, Universitätsstr. 150, NDEF 06/783, D-44801 Bochum
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22
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Interaction of E. coli Hsp90 with DnaK Involves the DnaJ Binding Region of DnaK. J Mol Biol 2016; 429:858-872. [PMID: 28013030 DOI: 10.1016/j.jmb.2016.12.014] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2016] [Revised: 12/13/2016] [Accepted: 12/15/2016] [Indexed: 01/05/2023]
Abstract
The 90-kDa heat shock protein (Hsp90) is a widely conserved and ubiquitous molecular chaperone that participates in ATP-dependent protein remodeling in both eukaryotes and prokaryotes. It functions in conjunction with Hsp70 and the Hsp70 cochaperones, an Hsp40 (J-protein) and a nucleotide exchange factor. In Escherichia coli, the functional collaboration between Hsp90Ec and Hsp70, DnaK, requires that the two chaperones directly interact. We used molecular docking to model the interaction of Hsp90Ec and DnaK. The top-ranked docked model predicted that a region in the nucleotide-binding domain (NBD) of DnaK interacted with a region in the middle domain of Hsp90Ec. We then made substitution mutants in DnaK residues suggested by the model to interact with Hsp90Ec. Of the 12 mutants tested, 11 were defective or partially defective in their ability to interact with Hsp90Ecin vivo in a bacterial two-hybrid assay and in vitro in a bio-layer interferometry assay. These DnaK mutants were also defective in their ability to function collaboratively in protein remodeling with Hsp90Ec but retained the ability to act with DnaK cochaperones. Taken together, these results suggest that a specific region in the NBD of DnaK is involved in the interaction with Hsp90Ec, and this interaction is functionally important. Moreover, the region of DnaK that we found to be necessary for Hsp90Ec binding includes residues that are also involved in J-protein binding, suggesting a functional interplay among DnaK, DnaK cochaperones, and Hsp90Ec.
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A Novel SRP Recognition Sequence in the Homeostatic Control Region of Heat Shock Transcription Factor σ32. Sci Rep 2016; 6:24147. [PMID: 27052372 PMCID: PMC4823717 DOI: 10.1038/srep24147] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2016] [Accepted: 03/21/2016] [Indexed: 12/29/2022] Open
Abstract
Heat shock response (HSR) generally plays a major role in sustaining protein homeostasis. In Escherichia coli, the activity and amount of the dedicated transcription factor σ32 transiently increase upon heat shock. The initial induction is followed by chaperone-mediated negative feedback to inactivate and degrade σ32. Previous work reported that signal recognition particle (SRP)-dependent targeting of σ32 to the membrane is essential for feedback control, though how SRP recognizes σ32 remained unknown. Extensive photo- and disulfide cross-linking studies in vivo now reveal that the highly conserved regulatory region of σ32 that lacks a consecutive hydrophobic stretch interacts with the signal peptide-binding site of Ffh (the protein subunit of SRP). Importantly, the σ32–Ffh interaction observed was significantly affected by mutations in this region that compromise the feedback regulation, but not by deleting the DnaK/DnaJ chaperones. Homeostatic regulation of HSR thus requires a novel type of SRP recognition mechanism.
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24
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Patra M, Roy SS, Dasgupta R, Basu T. GroEL to DnaK chaperone network behind the stability modulation of σ32at physiological temperature inEscherichia coli. FEBS Lett 2015; 589:4047-52. [DOI: 10.1016/j.febslet.2015.10.034] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2015] [Revised: 10/24/2015] [Accepted: 10/27/2015] [Indexed: 01/29/2023]
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Kumar CMS, Mande SC, Mahajan G. Multiple chaperonins in bacteria--novel functions and non-canonical behaviors. Cell Stress Chaperones 2015; 20:555-74. [PMID: 25986150 PMCID: PMC4463927 DOI: 10.1007/s12192-015-0598-8] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2015] [Revised: 04/29/2015] [Accepted: 04/30/2015] [Indexed: 01/05/2023] Open
Abstract
Chaperonins are a class of molecular chaperones that assemble into a large double ring architecture with each ring constituting seven to nine subunits and enclosing a cavity for substrate encapsulation. The well-studied Escherichia coli chaperonin GroEL binds non-native substrates and encapsulates them in the cavity thereby sequestering the substrates from unfavorable conditions and allowing the substrates to fold. Using this mechanism, GroEL assists folding of about 10-15 % of cellular proteins. Surprisingly, about 30 % of the bacteria express multiple chaperonin genes. The presence of multiple chaperonins raises questions on whether they increase general chaperoning ability in the cell or have developed specific novel cellular roles. Although the latter view is widely supported, evidence for the former is beginning to appear. Some of these chaperonins can functionally replace GroEL in E. coli and are generally indispensable, while others are ineffective and likewise are dispensable. Additionally, moonlighting functions for several chaperonins have been demonstrated, indicating a functional diversity among the chaperonins. Furthermore, proteomic studies have identified diverse substrate pools for multiple chaperonins. We review the current perception on multiple chaperonins and their physiological and functional specificities.
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Affiliation(s)
- C M Santosh Kumar
- Laboratory of Structural Biology, National Centre for Cell Science, Pune, 411007, India,
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26
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Ko KY, Geornaras I, Byelashov OA, Paik HD, Kim KT, Sofos JN. Thermotolerance of Rifampicin-Resistant E
scherichia coli
O157:H7 Derivatives and Their Parental Strains in a Broth System. J Food Saf 2015. [DOI: 10.1111/jfs.12207] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Kyung Yuk Ko
- Center for Meat Safety & Quality; Department of Animal Sciences; Colorado State University; Fort Collins CO 80523
- Division of Food Additives and Packaging; Department of Food Safety Evaluation; Ministry of Food Drug Safety; Cheongwon-gun Chungbuk Korea
| | - Ifigenia Geornaras
- Center for Meat Safety & Quality; Department of Animal Sciences; Colorado State University; Fort Collins CO 80523
| | - Oleksandr A. Byelashov
- Center for Meat Safety & Quality; Department of Animal Sciences; Colorado State University; Fort Collins CO 80523
| | - Hyun-Dong Paik
- Department of Food Science and Biotechnology of Animal Resources; Konkuk University; Seoul Korea
| | - Kee-Tae Kim
- Department of Food Science and Biotechnology of Animal Resources; Konkuk University; Seoul Korea
| | - John N. Sofos
- Center for Meat Safety & Quality; Department of Animal Sciences; Colorado State University; Fort Collins CO 80523
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27
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Liu Y, Tang H, Lin Z, Xu P. Mechanisms of acid tolerance in bacteria and prospects in biotechnology and bioremediation. Biotechnol Adv 2015; 33:1484-92. [PMID: 26057689 DOI: 10.1016/j.biotechadv.2015.06.001] [Citation(s) in RCA: 124] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2014] [Revised: 06/02/2015] [Accepted: 06/02/2015] [Indexed: 02/05/2023]
Abstract
Acidogenic and aciduric bacteria have developed several survival systems in various acidic environments to prevent cell damage due to acid stress such as that on the human gastric surface and in the fermentation medium used for industrial production of acidic products. Common mechanisms for acid resistance in bacteria are proton pumping by F1-F0-ATPase, the glutamate decarboxylase system, formation of a protective cloud of ammonia, high cytoplasmic urease activity, repair or protection of macromolecules, and biofilm formation. The field of synthetic biology has rapidly advanced and generated an ever-increasing assortment of genetic devices and biological modules for applications in biofuel and novel biomaterial productions. Better understanding of aspects such as overproduction of general shock proteins, molecular mechanisms, and responses to cell density adopted by microorganisms for survival in low pH conditions will prove useful in synthetic biology for potential industrial and environmental applications.
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Affiliation(s)
- Yuping Liu
- State Key Laboratory of Microbial Metabolism, Shanghai Jiao Tong University, Shanghai 200240, People's Republic of China; School of Life Sciences & Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, People's Republic of China
| | - Hongzhi Tang
- State Key Laboratory of Microbial Metabolism, Shanghai Jiao Tong University, Shanghai 200240, People's Republic of China; School of Life Sciences & Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, People's Republic of China.
| | - Zhanglin Lin
- Department of Chemical Engineering, Tsinghua University, One Tsinghua Garden Road, Beijing 100084, People's Republic of China
| | - Ping Xu
- State Key Laboratory of Microbial Metabolism, Shanghai Jiao Tong University, Shanghai 200240, People's Republic of China; School of Life Sciences & Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, People's Republic of China.
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28
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Schroda M, Hemme D, Mühlhaus T. The Chlamydomonas heat stress response. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2015; 82:466-480. [PMID: 25754362 DOI: 10.1111/tpj.12816] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/24/2014] [Revised: 02/25/2015] [Accepted: 02/26/2015] [Indexed: 05/18/2023]
Abstract
Heat waves occurring at increased frequency as a consequence of global warming jeopardize crop yield safety. One way to encounter this problem is to genetically engineer crop plants toward increased thermotolerance. To identify entry points for genetic engineering, a thorough understanding of how plant cells perceive heat stress and respond to it is required. Using the unicellular green alga Chlamydomonas reinhardtii as a model system to study the fundamental mechanisms of the plant heat stress response has several advantages. Most prominent among them is the suitability of Chlamydomonas for studying stress responses system-wide and in a time-resolved manner under controlled conditions. Here we review current knowledge on how heat is sensed and signaled to trigger temporally and functionally grouped sub-responses termed response elements to prevent damage and to maintain cellular homeostasis in plant cells.
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Affiliation(s)
- Michael Schroda
- Molecular Biotechnology & Systems Biology, TU Kaiserslautern, Paul-Ehrlich-Straße 23, 67663, Kaiserslautern, Germany
| | - Dorothea Hemme
- Molecular Biotechnology & Systems Biology, TU Kaiserslautern, Paul-Ehrlich-Straße 23, 67663, Kaiserslautern, Germany
| | - Timo Mühlhaus
- Molecular Biotechnology & Systems Biology, TU Kaiserslautern, Paul-Ehrlich-Straße 23, 67663, Kaiserslautern, Germany
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29
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Xu X, Niu Y, Liang K, Wang J, Li X, Yang Y. Heat shock transcription factor δ³² is targeted for degradation via an ubiquitin-like protein ThiS in Escherichia coli. Biochem Biophys Res Commun 2015; 459:240-245. [PMID: 25721662 DOI: 10.1016/j.bbrc.2015.02.087] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2015] [Accepted: 02/13/2015] [Indexed: 01/09/2023]
Abstract
The posttranslational modification of proteins with ubiquitin and ubiquitin-like proteins (UBLs) plays an important role in eukaryote biology, through which substrate proteins are targeted for degradation by the proteasome. Prokaryotes have been thought to degrade proteins by an ubiquitin independent pathway. Here, we show that ThiS, an ubiquitin-like protein, is covalently attached to δ(32) and at least 27 other proteins, leading to their subsequent degradation by proteases, in a similar manner to the ubiquitin-proteasome system (UPS) in eukaryotes. Molecular biology and biochemical studies confirm that specific lysine sites in δ(32) can be modified by ThiS. The results presented here establish a new model for δ(32) degradation and show that Escherichia coli uses a small-protein modifier to control protein stability.
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Affiliation(s)
- Xibing Xu
- Key Laboratory of Bio-Resources and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu 610064, China
| | - Yulong Niu
- Key Laboratory of Bio-Resources and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu 610064, China
| | - Ke Liang
- Key Laboratory of Bio-Resources and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu 610064, China
| | - Jianmei Wang
- Key Laboratory of Bio-Resources and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu 610064, China
| | - Xufeng Li
- Key Laboratory of Bio-Resources and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu 610064, China
| | - Yi Yang
- Key Laboratory of Bio-Resources and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu 610064, China.
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Ito F, Tamiya T, Ohtsu I, Fujimura M, Fukumori F. Genetic and phenotypic characterization of the heat shock response in Pseudomonas putida. Microbiologyopen 2014; 3:922-36. [PMID: 25303383 PMCID: PMC4263515 DOI: 10.1002/mbo3.217] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2014] [Revised: 09/18/2014] [Accepted: 09/19/2014] [Indexed: 12/22/2022] Open
Abstract
Molecular chaperones function in various important physiological processes. Null mutants of genes for the molecular chaperone ClpB (Hsp104), and those that encode J-domain proteins (DnaJ, CbpA, and DjlA), which may act as Hsp40 co-chaperones of DnaK (Hsp70), were constructed from Pseudomonas putida KT2442 (KT) to elucidate their roles. The KTΔclpB mutant showed the same heat shock response (HSR) as the wild-type, both in terms of heat-shock protein (Hsp) synthesis (other than ClpB) and in hsp gene expression; however, the mutant was quite sensitive to high temperatures and was unable to disaggregate into thermo-mediated protein aggregates, indicating that ClpB is important for cell survival after heat stress and essential for solubilization of protein aggregates. On the other hand, the KTΔdnaJ mutant was temperature-sensitive, and formed more protein aggregates (especially of high molecular weight) upon heat stress than did KT. P. putida CbpA, a probable Hsp, partially substituted the functions of DnaJ in cell growth and solubilization of thermo-mediated protein aggregates, and might be involved in the HSR which was regulated by a fine-tuning system(s) that could sense subtle changes in the ambient temperature and control the levels of σ32 activity and quantity, as well as the mRNA levels of hsp genes.
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Affiliation(s)
- Fumihiro Ito
- Graduate School of Life Sciences, Toyo University, Gunma
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31
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In vitro characterization of bacterial and chloroplast Hsp70 systems reveals an evolutionary optimization of the co-chaperones for their Hsp70 partner. Biochem J 2014; 460:13-24. [PMID: 24564700 DOI: 10.1042/bj20140001] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
The chloroplast Hsp70 (heat-shock protein of 70 kDa) system involved in protein folding in Chlamydomonas reinhardtii consists of HSP70B, the DnaJ homologue CDJ1 and the GrpE-type nucleotide-exchange factor CGE1. The finding that HSP70B needs to be co-expressed with HEP2 (Hsp70 escort protein 2) to become functional allowed the reconstitution of the chloroplast Hsp70 system in vitro and comparison with the homologous Escherichia coli system. Both systems support luciferase refolding and display ATPase and holdase activities. Steady-state activities are low and strongly stimulated by the co-chaperones, whose concentrations need to be balanced to optimally support luciferase refolding. Although the co-chaperones of either system generally stimulate ATPase and folding-assistance activities of the other, luciferase refolding is reduced ~10-fold and <2-fold if either Hsp70 is supplemented with the foreign DnaJ and GrpE protein respectively, suggesting an evolutionary specialization of the co-chaperones for their Hsp70 partner. Distinct features are that HSP70B's steady-state ATPase exhibits ~20-fold higher values for Vmax and Km and that the HSP70B system displays a ~6-fold higher folding assistance on denatured luciferase. Although truncating up to 16 N-terminal amino acids of CGE1 does not affect HSP70B's general ATPase and folding-assistance activities in the physiological temperature range, further deletions hampering dimerization of CGE1 via its N-terminal coiled coil do.
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32
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Wong KS, Snider JD, Graham C, Greenblatt JF, Emili A, Babu M, Houry WA. The MoxR ATPase RavA and its cofactor ViaA interact with the NADH:ubiquinone oxidoreductase I in Escherichia coli. PLoS One 2014; 9:e85529. [PMID: 24454883 PMCID: PMC3893208 DOI: 10.1371/journal.pone.0085529] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2013] [Accepted: 11/27/2013] [Indexed: 12/26/2022] Open
Abstract
MoxR ATPases are widespread throughout bacteria and archaea. The experimental evidence to date suggests that these proteins have chaperone-like roles in facilitating the maturation of dedicated protein complexes that are functionally diverse. In Escherichia coli, the MoxR ATPase RavA and its putative cofactor ViaA are found to exist in early stationary-phase cells at 37 °C at low levels of about 350 and 90 molecules per cell, respectively. Both proteins are predominantly localized to the cytoplasm, but ViaA was also unexpectedly found to localize to the cell membrane. Whole genome microarrays and synthetic lethality studies both indicated that RavA-ViaA are genetically linked to Fe-S cluster assembly and specific respiratory pathways. Systematic analysis of mutant strains of ravA and viaA indicated that RavA-ViaA sensitizes cells to sublethal concentrations of aminoglycosides. Furthermore, this effect was dependent on RavA's ATPase activity, and on the presence of specific subunits of NADH:ubiquinone oxidoreductase I (Nuo Complex, or Complex I). Importantly, both RavA and ViaA were found to physically interact with specific Nuo subunits. We propose that RavA-ViaA facilitate the maturation of the Nuo complex.
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Affiliation(s)
- Keith S. Wong
- Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada
| | - Jamie D. Snider
- Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada
| | - Chris Graham
- Department of Biochemistry, Research and Innovation Centre, University of Regina, Regina, Saskatchewan, Canada
| | - Jack F. Greenblatt
- Banting and Best Department of Medical Research, Terrence Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, Ontario, Canada
| | - Andrew Emili
- Banting and Best Department of Medical Research, Terrence Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, Ontario, Canada
| | - Mohan Babu
- Department of Biochemistry, Research and Innovation Centre, University of Regina, Regina, Saskatchewan, Canada
| | - Walid A. Houry
- Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada
- * E-mail:
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Lim B, Miyazaki R, Neher S, Siegele DA, Ito K, Walter P, Akiyama Y, Yura T, Gross CA. Heat shock transcription factor σ32 co-opts the signal recognition particle to regulate protein homeostasis in E. coli. PLoS Biol 2013; 11:e1001735. [PMID: 24358019 PMCID: PMC3866087 DOI: 10.1371/journal.pbio.1001735] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2013] [Accepted: 10/23/2013] [Indexed: 11/18/2022] Open
Abstract
The bacterial heat shock transcription factor, σ32, maintains proper protein homeostasis only after it is targeted to the inner membrane by the signal recognition particle (SRP), thereby enabling integration of protein folding information from both the cytoplasm and cell membrane. All cells must adapt to rapidly changing conditions. The heat shock response (HSR) is an intracellular signaling pathway that maintains proteostasis (protein folding homeostasis), a process critical for survival in all organisms exposed to heat stress or other conditions that alter the folding of the proteome. Yet despite decades of study, the circuitry described for responding to altered protein status in the best-studied bacterium, E. coli, does not faithfully recapitulate the range of cellular responses in response to this stress. Here, we report the discovery of the missing link. Surprisingly, we found that σ32, the central transcription factor driving the HSR, must be localized to the membrane rather than dispersed in the cytoplasm as previously assumed. Genetic analyses indicate that σ32 localization results from a protein targeting reaction facilitated by the signal recognition particle (SRP) and its receptor (SR), which together comprise a conserved protein targeting machine and mediate the cotranslational targeting of inner membrane proteins to the membrane. SRP interacts with σ32 directly and transports it to the inner membrane. Our results show that σ32 must be membrane-associated to be properly regulated in response to the protein folding status in the cell, explaining how the HSR integrates information from both the cytoplasm and bacterial cell membrane. All cells have to adjust to frequent changes in their environmental conditions. The heat shock response is a signaling pathway critical for survival of all organisms exposed to elevated temperatures. Under such conditions, the heat shock response maintains enzymes and other proteins in a properly folded state. The mechanisms for sensing temperature and the subsequent induction of the appropriate transcriptional response have been extensively studied. Prior to this work, however, the circuitry described in the best studied bacterium E. coli could not fully explain the range of cellular responses that are observed following heat shock. We report the discovery of this missing link. Surprisingly, we find that σ32, a transcription factor that induces gene expression during heat shock, needs to be localized to the membrane, rather than being active as a soluble cytoplasmic protein as previously thought. We show that, equally surprisingly, σ32 is targeted to the membrane by the signal recognition particle (SRP) and its receptor (SR). SRP and SR constitute a conserved protein targeting machine that normally only operates on membrane and periplasmic proteins that contain identifiable signal sequences. Intriguingly, σ32 does not have any canonical signal sequence for export or membrane-integration. Our results indicate that membrane-associated σ32, not soluble cytoplasmic σ32, is the preferred target of regulatory control in response to heat shock. Our new model thus explains how protein folding status from both the cytoplasm and bacterial cell membrane can be integrated to control the heat shock response.
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Affiliation(s)
- Bentley Lim
- Department of Microbiology and Immunology, University of California at San Francisco, San Francisco, California, United States of America
| | - Ryoji Miyazaki
- Institute for Virus Research, Kyoto University, Kyoto, Japan
| | - Saskia Neher
- Department of Biochemistry and Biophysics and Howard Hughes Medical Institute, University of California at San Francisco, San Francisco, California United States of America
| | - Deborah A. Siegele
- Department of Biology, Texas A&M University, College Station, Texas, United States of America
| | - Koreaki Ito
- Faculty of Life Sciences, Kyoto Sangyo University, Kyoto, Japan
| | - Peter Walter
- Department of Biochemistry and Biophysics and Howard Hughes Medical Institute, University of California at San Francisco, San Francisco, California United States of America
| | - Yoshinori Akiyama
- Institute for Virus Research, Kyoto University, Kyoto, Japan
- * E-mail: (Y.A.); (T.Y.); (C.A.G.)
| | - Takashi Yura
- Faculty of Life Sciences, Kyoto Sangyo University, Kyoto, Japan
- * E-mail: (Y.A.); (T.Y.); (C.A.G.)
| | - Carol A. Gross
- Department of Microbiology and Immunology, University of California at San Francisco, San Francisco, California, United States of America
- Department of Cell and Tissue Biology, University of California at San Francisco, San Francisco, California, United States
- * E-mail: (Y.A.); (T.Y.); (C.A.G.)
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Schmollinger S, Schulz-Raffelt M, Strenkert D, Veyel D, Vallon O, Schroda M. Dissecting the heat stress response in Chlamydomonas by pharmaceutical and RNAi approaches reveals conserved and novel aspects. MOLECULAR PLANT 2013; 6:1795-1813. [PMID: 23713078 DOI: 10.1093/mp/sst086] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
To study how conserved fundamental concepts of the heat stress response (HSR) are in photosynthetic eukaryotes, we applied pharmaceutical and antisense/amiRNA approaches to the unicellular green alga Chlamydomonas reinhardtii. The Chlamydomonas HSR appears to be triggered by the accumulation of unfolded proteins, as it was induced at ambient temperatures by feeding cells with the arginine analog canavanine. The protein kinase inhibitor staurosporine strongly retarded the HSR, demonstrating the importance of phosphorylation during activation of the HSR also in Chlamydomonas. While the removal of extracellular calcium by the application of EGTA and BAPTA inhibited the HSR in moss and higher plants, only the addition of BAPTA, but not of EGTA, retarded the HSR and impaired thermotolerance in Chlamydomonas. The addition of cycloheximide, an inhibitor of cytosolic protein synthesis, abolished the attenuation of the HSR, indicating that protein synthesis is necessary to restore proteostasis. HSP90 inhibitors induced a stress response when added at ambient conditions and retarded attenuation of the HSR at elevated temperatures. In addition, we detected a direct physical interaction between cytosolic HSP90A/HSP70A and heat shock factor 1, but surprisingly this interaction persisted after the onset of stress. Finally, the expression of antisense constructs targeting chloroplast HSP70B resulted in a delay of the cell's entire HSR, thus suggesting the existence of a retrograde stress signaling cascade that is desensitized in HSP70B-antisense strains.
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Affiliation(s)
- Stefan Schmollinger
- Molekulare Biotechnologie und Systembiologie, TU Kaiserslautern, Paul-Ehrlich-Str. 23, D-67663 Kaiserslautern, Germany
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Jonas K, Liu J, Chien P, Laub MT. Proteotoxic stress induces a cell-cycle arrest by stimulating Lon to degrade the replication initiator DnaA. Cell 2013; 154:623-36. [PMID: 23911325 DOI: 10.1016/j.cell.2013.06.034] [Citation(s) in RCA: 101] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2013] [Revised: 05/15/2013] [Accepted: 06/20/2013] [Indexed: 10/26/2022]
Abstract
The decision to initiate DNA replication is a critical step in the cell cycle of all organisms. Cells often delay replication in the face of stressful conditions, but the underlying mechanisms remain incompletely defined. Here, we demonstrate in Caulobacter crescentus that proteotoxic stress induces a cell-cycle arrest by triggering the degradation of DnaA, the conserved replication initiator. A depletion of available Hsp70 chaperone, DnaK, either through genetic manipulation or heat shock, induces synthesis of the Lon protease, which can directly degrade DnaA. Unexpectedly, we find that unfolded proteins, which accumulate following a loss of DnaK, also allosterically activate Lon to degrade DnaA, thereby ensuring a cell-cycle arrest. Our work reveals a mechanism for regulating DNA replication under adverse growth conditions. Additionally, our data indicate that unfolded proteins can actively and directly alter substrate recognition by cellular proteases.
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Affiliation(s)
- Kristina Jonas
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
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36
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Krishnan K, Duncan MJ. Role of sodium in the RprY-dependent stress response in Porphyromonas gingivalis. PLoS One 2013; 8:e63180. [PMID: 23671672 PMCID: PMC3646045 DOI: 10.1371/journal.pone.0063180] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2012] [Accepted: 03/31/2013] [Indexed: 01/09/2023] Open
Abstract
Porphyromonas gingivalis is a Gram-negative oral anaerobe which is strongly associated with periodontal disease. Environmental changes in the gingival sulcus trigger the growth of P. gingivalis and a concurrent shift from periodontal health to disease. Bacteria adjust their physiology in response to environmental changes and gene regulation by two-component phospho-relay systems is one mechanism by which such adjustments are effected. In P. gingivalis RprY is an orphan response regulator and previously we showed that the RprY regulon included genes associated with oxidative stress and sodium metabolism. The goals of the present study were to identify environmental signals that induce rprY and clarify the role of the regulator in the stress response. In Escherichia coli an RprY-LacZ fusion protein was induced in sodium- depleted medium and a P. gingivalis rprY mutant was unable to grow in similar medium. By several approaches we established that sodium depletion induced up-regulation of genes involved in oxidative stress. In addition, we demonstrated that RprY interacted directly with the promoters of several molecular chaperones. Further, both genetic and transcription data suggest that the regulator acts as a repressor. We conclude that RprY is one of the regulators that controls stress responses in P. gingivalis, possibly by acting as a repressor since an rprY mutant showed a superstress reponse in sodium-depleted medium which we propose inhibited growth.
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Affiliation(s)
- Karthik Krishnan
- Department of Microbiology, The Forsyth Institute, Cambridge, Massachusetts, United States of America
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Mel’kina OE, Goryanin II, Manukhov IV, Zavil’gel’skii GB. Trigger factor-dependent refolding of bacterial luciferases in Escherichia coli: Kinetics, efficiency, and effect of bichaperone system. Mol Biol 2013. [DOI: 10.1134/s0026893313030072] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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38
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Park HS, Jeong WJ, Kim E, Jung Y, Lim JM, Hwang MS, Park EJ, Ha DS, Choi DW. Heat shock protein gene family of the Porphyra seriata and enhancement of heat stress tolerance by PsHSP70 in Chlamydomonas. MARINE BIOTECHNOLOGY (NEW YORK, N.Y.) 2012; 14:332-342. [PMID: 22068390 DOI: 10.1007/s10126-011-9417-0] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/27/2011] [Accepted: 10/13/2011] [Indexed: 05/31/2023]
Abstract
Heat shock proteins and molecular chaperones are key components contributing to survival in the abiotic stress response. Porphyra seriata grows on intertidal rocks exposed to dynamic environmental changes associated with the turning tides, including desiccation and heat stress. Analysis of the ESTs of P. seriata allows us to identify the nine HSP cDNAs, which are predicted to be PsHSP90, three PsHSP70, PsHSP40 and PsHSP20, and three 5'-truncated HSP cDNAs. RT-PCR results show that most of the PsHSP transcripts were detected under normal cell growth conditions as well as heat stress, with the exception of two cDNAs. In particular, PsHSP70b and PsHSP20 transcripts were upregulated by heat stress. When the putative mitochondrial PsHSP70b was introduced and overexpressed in Chlamydomonas, transformed Chlamydomonas evidenced higher rates of survival and growth than those of the wild type under heat stress conditions. Constitutive overexpression of the PsHSP70b gene increases the transcription of the HSF1 as well as the CrHSP20 and CrHSP70 gene. These results indicate that PsHSP70b is involved in tolerance to heat stress and the effects on transcription of the CrHSP20 and CrHSP70 genes.
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Affiliation(s)
- Hong-Sil Park
- Department of Biology Education and Kumho Life Science Laboratory, Chonnam National University, Kwangju 500-757, South Korea
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Reichmann D, Xu Y, Cremers CM, Ilbert M, Mittelman R, Fitzgerald MC, Jakob U. Order out of disorder: working cycle of an intrinsically unfolded chaperone. Cell 2012; 148:947-57. [PMID: 22385960 DOI: 10.1016/j.cell.2012.01.045] [Citation(s) in RCA: 102] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2011] [Revised: 10/23/2011] [Accepted: 01/31/2012] [Indexed: 11/15/2022]
Abstract
The redox-regulated chaperone Hsp33 protects organisms against oxidative stress that leads to protein unfolding. Activation of Hsp33 is triggered by the oxidative unfolding of its own redox-sensor domain, making Hsp33 a member of a recently discovered class of chaperones that require partial unfolding for full chaperone activity. Here we address the long-standing question of how chaperones recognize client proteins. We show that Hsp33 uses its own intrinsically disordered regions to discriminate between unfolded and partially structured folding intermediates. Binding to secondary structure elements in client proteins stabilizes Hsp33's intrinsically disordered regions, and this stabilization appears to mediate Hsp33's high affinity for structured folding intermediates. Return to nonstress conditions reduces Hsp33's disulfide bonds, which then significantly destabilizes the bound client proteins and in doing so converts them into less-structured, folding-competent client proteins of ATP-dependent foldases. We propose a model in which energy-independent chaperones use internal order-to-disorder transitions to control substrate binding and release.
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Affiliation(s)
- Dana Reichmann
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI 48109, USA
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40
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Suppression of a dnaKJ deletion by multicopy dksA results from non-feedback-regulated transcripts that originate upstream of the major dksA promoter. J Bacteriol 2012; 194:1437-46. [PMID: 22267514 DOI: 10.1128/jb.06726-11] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
DksA is an RNA polymerase (RNAP) binding transcription factor that controls expression of a large number of genes in concert with the small-molecule "alarmone" ppGpp. DksA also aids in the resolution of conflicts between RNAP and DNA polymerase (DNAP) during genome replication. DksA was originally identified as a multicopy suppressor of the temperature sensitivity caused by deletion of the genes coding for the DnaKJ chaperone system. Here, we address a longstanding question regarding the role of DksA in ΔdnaKJ suppression. We demonstrate that DksA expression from a multicopy plasmid is necessary and sufficient for suppression, that overexpression occurs despite the fact that the major dksA promoter is feedback regulated in wild-type cells, and that weak, non-feedback-regulated transcription originating upstream of the major promoter for the dksA gene accounts for overexpression. We tentatively rule out three potential explanations for suppression related to known functions of DnaKJ. Because a determinant in DksA needed for the regulation of transcription initiation, but not for resolution of RNAP-DNAP conflicts, is needed to bypass the need for DnaKJ, we suggest that suppression results from an unidentified product whose promoter is directly or indirectly regulated by DksA.
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42
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Ribeiro DA, Ferraz LFC, Vicentini R, Ottoboni LMM. Gene expression modulation by heat stress in Acidithiobacillus ferrooxidans LR. Antonie van Leeuwenhoek 2011; 101:583-93. [PMID: 22086463 DOI: 10.1007/s10482-011-9673-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/15/2011] [Accepted: 11/03/2011] [Indexed: 11/27/2022]
Abstract
During bioleaching, Acidithiobacillus ferrooxidans is subjected to different types of stress, including heat stress, which affect bacterial growth. In this work, real time quantitative PCR was used to analyze the expression of heat shock genes, as well as genes that encode proteins related to several functional categories in A. ferrooxidans. Cells were submitted to long-term growth and heat shock, both at 40°C. The results showed that heat shock affected the expression levels of most genes investigated, whilst long-term growth at 40°C resulted in minor changes in gene expression, except for certain genes related to iron transport, which were strongly down-regulated, suggesting that the iron processing capability of A. ferrooxidans was affected by long-term growth at 40°C. A bioinformatic analysis of the genes' promoter regions indicated a putative transcriptional regulation by the σ(32) factor in 12 of the 31 genes investigated, suggesting the involvement of other regulatory mechanisms in the response of A. ferrooxidans to heat stress.
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Affiliation(s)
- Daniela A Ribeiro
- Center for Molecular Biology and Genetic Engineering, State University of Campinas, Campinas, SP, Brazil
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43
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Gur E, Biran D, Ron EZ. Regulated proteolysis in Gram-negative bacteria--how and when? Nat Rev Microbiol 2011; 9:839-48. [PMID: 22020261 DOI: 10.1038/nrmicro2669] [Citation(s) in RCA: 101] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Most bacteria live in a dynamic environment where temperature, availability of nutrients and the presence of various chemicals vary, which requires rapid adaptation. Many of the adaptive changes are determined by changes in the transcription of global regulatory networks, but this response is slow because most bacterial proteins are stable and their concentration remains high even after transcription slows down. To respond rapidly, an additional level of regulation has evolved: the degradation of key proteins. However, as proteolysis is an irreversible process, it is subject to tight regulation of substrate binding and degradation. Here we review the roles of the proteolytic enzymes in Gram-negative bacteria and how these enzymes can be regulated to target only a subset of proteins.
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Affiliation(s)
- Eyal Gur
- Department of Life Sciences, Ben-Gurion University of the Negev, Beer Sheva, Israel
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44
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Molecular strategy for survival at a critical high temperature in Eschierichia coli. PLoS One 2011; 6:e20063. [PMID: 21695201 PMCID: PMC3112155 DOI: 10.1371/journal.pone.0020063] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2011] [Accepted: 04/12/2011] [Indexed: 01/19/2023] Open
Abstract
The molecular mechanism supporting survival at a critical high temperature (CHT) in Escherichia coli was investigated. Genome-wide screening with a single-gene knockout library provided a list of genes indispensable for growth at 47°C, called thermotolerant genes. Genes for which expression was affected by exposure to CHT were identified by DNA chip analysis. Unexpectedly, the former contents did not overlap with the latter except for dnaJ and dnaK, indicating that a specific set of non-heat shock genes is required for the organism to survive under such a severe condition. More than half of the mutants of the thermotolerant genes were found to be sensitive to H2O2 at 30°C, suggesting that the mechanism of thermotolerance partially overlaps with that of oxidative stress resistance. Their encoded enzymes or proteins are related to outer membrane organization, DNA double-strand break repair, tRNA modification, protein quality control, translation control or cell division. DNA chip analyses of essential genes suggest that many of the genes encoding ribosomal proteins are down-regulated at CHT. Bioinformatics analysis and comparison with the genomic information of other microbes suggest that E. coli possesses several systems for survival at CHT. This analysis allows us to speculate that a lipopolysaccharide biosynthesis system for outer membrane organization and a sulfur-relay system for tRNA modification have been acquired by horizontal gene transfer.
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45
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Grudniak AM, Kurek A, Szarlak J, Wolska KI. Oleanolic and ursolic acids influence affect the expression of the cysteine regulon and the stress response in Escherichia coli. Curr Microbiol 2011; 62:1331-6. [PMID: 21221969 DOI: 10.1007/s00284-010-9866-0] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2010] [Accepted: 12/30/2010] [Indexed: 10/18/2022]
Abstract
The pentacyclic triterpenoids, oleanolic, and ursolic acids, affect peptidoglycan metabolism, altering bacterial morphology, and inhibit the growth and survival of several bacterial species, including pathogenic ones. We investigated the effect of subinhibitory concentrations of these compounds on the expression of three operons from the E. coli cysteine regulon, cysPTWA, cysJIH, and cysB, by using transcriptional fusions with the lacZ reporter gene. An inhibitory effect on β-galactosidase expression directed by all three chromosomal fusions was observed with both compounds. In addition, oleanolic acid, but not ursolic acid, caused a weak increase in DnaK synthesis, suggesting moderate ability of inducing heat-shock response.
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Affiliation(s)
- Anna M Grudniak
- Department of Bacterial Genetics, Institute of Microbiology, Faculty of Biology, University of Warsaw, Miecznikowa 1, 02-096 Warsaw, Poland.
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46
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Sabate R, de Groot NS, Ventura S. Protein folding and aggregation in bacteria. Cell Mol Life Sci 2010; 67:2695-715. [PMID: 20358253 PMCID: PMC11115605 DOI: 10.1007/s00018-010-0344-4] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2010] [Revised: 02/19/2010] [Accepted: 03/05/2010] [Indexed: 01/31/2023]
Abstract
Proteins might experience many conformational changes and interactions during their lifetimes, from their synthesis at ribosomes to their controlled degradation. Because, in most cases, only folded proteins are functional, protein folding in bacteria is tightly controlled genetically, transcriptionally, and at the protein sequence level. In addition, important cellular machinery assists the folding of polypeptides to avoid misfolding and ensure the attainment of functional structures. When these redundant protective strategies are overcome, misfolded polypeptides are recruited into insoluble inclusion bodies. The protein embedded in these intracellular deposits might display different conformations including functional and beta-sheet-rich structures. The latter assemblies are similar to the amyloid fibrils characteristic of several human neurodegenerative diseases. Interestingly, bacteria exploit the same structural principles for functional properties such as adhesion or cytotoxicity. Overall, this review illustrates how prokaryotic organisms might provide the bedrock on which to understand the complexity of protein folding and aggregation in the cell.
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Affiliation(s)
- Raimon Sabate
- Departament de Bioquímica i Biologia Molecular, Institut de Biotecnologia i de Biomedicina, Universitat Autònoma de Barcelona, 08193 Bellaterra, Barcelona, Spain
| | - Natalia S. de Groot
- Departament de Bioquímica i Biologia Molecular, Institut de Biotecnologia i de Biomedicina, Universitat Autònoma de Barcelona, 08193 Bellaterra, Barcelona, Spain
| | - Salvador Ventura
- Departament de Bioquímica i Biologia Molecular, Institut de Biotecnologia i de Biomedicina, Universitat Autònoma de Barcelona, 08193 Bellaterra, Barcelona, Spain
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Abstract
Since its discovery in 1924 by J Clarke, Streptococcus mutans has been the focus of rigorous research efforts due to its involvement in caries initiation and progression. Its ability to ferment a range of dietary carbohydrates can rapidly drop the external environmental pH, thereby making dental plaque inhabitable to many competing species and can ultimately lead to tooth decay. Acid production by this oral pathogen would prove suicidal if not for its remarkable ability to withstand the acid onslaught by utilizing a wide variety of highly evolved acid-tolerance mechanisms. The elucidation of these mechanisms will be discussed, serving as the focus of this review.
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Affiliation(s)
- Robert Matsui
- Room 449A Faculty of Dentistry, University of Toronto, 124 Edward St., Toronto, ON, M5G 1G6, Canada, Tel.: +1 416 979 4917 ext. 4592, Fax: +1 416 978 4936
| | - Dennis Cvitkovitch
- Room 449A Faculty of Dentistry, University of Toronto, 124 Edward St., Toronto, ON, M5G 1G6, Canada, Tel.: +1 416 979 4917 ext. 4592, Fax: +1 416 978 4936
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48
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Jewett AI, Shea JE. Reconciling theories of chaperonin accelerated folding with experimental evidence. Cell Mol Life Sci 2010; 67:255-76. [PMID: 19851829 PMCID: PMC11115962 DOI: 10.1007/s00018-009-0164-6] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2009] [Revised: 09/14/2009] [Accepted: 09/25/2009] [Indexed: 10/20/2022]
Abstract
For the last 20 years, a large volume of experimental and theoretical work has been undertaken to understand how chaperones like GroEL can assist protein folding in the cell. The most accepted explanation appears to be the simplest: GroEL, like most other chaperones, helps proteins fold by preventing aggregation. However, evidence suggests that, under some conditions, GroEL can play a more active role by accelerating protein folding. A large number of models have been proposed to explain how this could occur. Focused experiments have been designed and carried out using different protein substrates with conclusions that support many different mechanisms. In the current article, we attempt to see the forest through the trees. We review all suggested mechanisms for chaperonin-mediated folding and weigh the plausibility of each in light of what we now know about the most stringent, essential, GroEL-dependent protein substrates.
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Affiliation(s)
- Andrew I. Jewett
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, CA 93106 USA
- Department of Physics, University of California, Santa Barbara, CA 93106 USA
| | - Joan-Emma Shea
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, CA 93106 USA
- Department of Physics, University of California, Santa Barbara, CA 93106 USA
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49
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New Insights into the Roles of Molecular Chaperones in Chlamydomonas and Volvox. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2010; 285:75-113. [DOI: 10.1016/b978-0-12-381047-2.00002-5] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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50
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Shenhar Y, Rasouly A, Biran D, Ron EZ. Adaptation ofEscherichi colito elevated temperatures involves a change in stability of heat shock gene transcripts. Environ Microbiol 2009; 11:2989-97. [DOI: 10.1111/j.1462-2920.2009.01993.x] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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