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Mu B, Nair AM, Zhao R. Plastid HSP90C C-terminal extension region plays a regulatory role in chaperone activity and client binding. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2024. [PMID: 38969341 DOI: 10.1111/tpj.16917] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/07/2024] [Revised: 06/11/2024] [Accepted: 06/22/2024] [Indexed: 07/07/2024]
Abstract
HSP90Cs are essential molecular chaperones localized in the plastid stroma that maintain protein homeostasis and assist the import and thylakoid transport of chloroplast proteins. While HSP90C contains all conserved domains as an HSP90 family protein, it also possesses a unique feature in its variable C-terminal extension (CTE) region. This study elucidated the specific function of this HSP90C CTE region. Our phylogenetic analyses revealed that this intrinsically disordered region contains a highly conserved DPW motif in the green lineages. With biochemical assays, we showed that the CTE is required for the chaperone to effectively interact with client proteins PsbO1 and LHCB2 to regulate ATP-independent chaperone activity and to effectuate its ATP hydrolysis. The CTE truncation mutants could support plant growth and development reminiscing the wild type under normal conditions except for a minor phenotype in cotyledon when expressed at a level comparable to wild type. However, higher HSP90C expression was observed to correlate with a stronger response to specific photosystem II inhibitor DCMU, and CTE truncations dampened the response. Additionally, when treated with lincomycin to inhibit chloroplast protein translation, CTE truncation mutants showed a delayed response to PsbO1 expression repression, suggesting its role in chloroplast retrograde signaling. Our study therefore provides insights into the mechanism of HSP90C in client protein binding and the regulation of green chloroplast maturation and function, especially under stress conditions.
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Affiliation(s)
- Bona Mu
- Department of Biological Sciences, University of Toronto Scarborough, Toronto, Canada
- Department of Cell and Systems Biology, University of Toronto, Toronto, Canada
| | - Adheip Monikantan Nair
- Department of Biological Sciences, University of Toronto Scarborough, Toronto, Canada
- Department of Cell and Systems Biology, University of Toronto, Toronto, Canada
| | - Rongmin Zhao
- Department of Biological Sciences, University of Toronto Scarborough, Toronto, Canada
- Department of Cell and Systems Biology, University of Toronto, Toronto, Canada
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2
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Kreis E, König K, Misir M, Niemeyer J, Sommer F, Schroda M. TurboID reveals the proxiomes of Chlamydomonas proteins involved in thylakoid biogenesis and stress response. PLANT PHYSIOLOGY 2023; 193:1772-1796. [PMID: 37310689 PMCID: PMC10602608 DOI: 10.1093/plphys/kiad335] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/03/2023] [Revised: 04/24/2023] [Accepted: 05/04/2023] [Indexed: 06/14/2023]
Abstract
In Chlamydomonas (Chlamydomonas reinhardtii), the VESICLE-INDUCING PROTEIN IN PLASTIDS 1 and 2 (VIPP1 and VIPP2) play roles in the sensing and coping with membrane stress and in thylakoid membrane biogenesis. To gain more insight into these processes, we aimed to identify proteins interacting with VIPP1/2 in the chloroplast and chose proximity labeling (PL) for this purpose. We used the transient interaction between the nucleotide exchange factor CHLOROPLAST GRPE HOMOLOG 1 (CGE1) and the stromal HEAT SHOCK PROTEIN 70B (HSP70B) as test system. While PL with APEX2 and BioID proved to be inefficient, TurboID resulted in substantial biotinylation in vivo. TurboID-mediated PL with VIPP1/2 as baits under ambient and H2O2 stress conditions confirmed known interactions of VIPP1 with VIPP2, HSP70B, and the CHLOROPLAST DNAJ HOMOLOG 2 (CDJ2). Proteins identified in the VIPP1/2 proxiomes can be grouped into proteins involved in the biogenesis of thylakoid membrane complexes and the regulation of photosynthetic electron transport, including PROTON GRADIENT REGULATION 5-LIKE 1 (PGRL1). A third group comprises 11 proteins of unknown function whose genes are upregulated under chloroplast stress conditions. We named them VIPP PROXIMITY LABELING (VPL). In reciprocal experiments, we confirmed VIPP1 in the proxiomes of VPL2 and PGRL1. Our results demonstrate the robustness of TurboID-mediated PL for studying protein interaction networks in the chloroplast of Chlamydomonas and pave the way for analyzing functions of VIPPs in thylakoid biogenesis and stress responses.
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Affiliation(s)
- Elena Kreis
- Molekulare Biotechnologie & Systembiologie, RPTU Kaiserslautern-Landau, Paul-Ehrlich Straße 23, D-67663 Kaiserslautern, Germany
| | - Katharina König
- Molekulare Biotechnologie & Systembiologie, RPTU Kaiserslautern-Landau, Paul-Ehrlich Straße 23, D-67663 Kaiserslautern, Germany
| | - Melissa Misir
- Molekulare Biotechnologie & Systembiologie, RPTU Kaiserslautern-Landau, Paul-Ehrlich Straße 23, D-67663 Kaiserslautern, Germany
| | - Justus Niemeyer
- Molekulare Biotechnologie & Systembiologie, RPTU Kaiserslautern-Landau, Paul-Ehrlich Straße 23, D-67663 Kaiserslautern, Germany
| | - Frederik Sommer
- Molekulare Biotechnologie & Systembiologie, RPTU Kaiserslautern-Landau, Paul-Ehrlich Straße 23, D-67663 Kaiserslautern, Germany
| | - Michael Schroda
- Molekulare Biotechnologie & Systembiologie, RPTU Kaiserslautern-Landau, Paul-Ehrlich Straße 23, D-67663 Kaiserslautern, Germany
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3
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Wang S, Du M, Dong L, Qu R, Ran D, Ma J, Wang X, Xu L, Li W, He Y, Zou X. Function and molecular mechanism analysis of CaLasSDE460 effector involved in the pathogenesis of "Candidatus Liberibacter asiaticus" in citrus. MOLECULAR HORTICULTURE 2023; 3:14. [PMID: 37789492 PMCID: PMC10514941 DOI: 10.1186/s43897-023-00062-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2022] [Accepted: 07/10/2023] [Indexed: 10/05/2023]
Abstract
Citrus Huanglongbing (HLB), caused by Candidatus Liberibacter asiaticus (CaLas), is the most serious disease worldwide. CaLasSDE460 was previously characterized as a potential virulence factor of CaLas. However, the function and mechanism of CaLasSDE460 involved in CaLas against citrus is still elusive. Here, we showed that transgenic expression of CaLasSDE460 in Wanjincheng oranges (C. sinensis Osbeck) contributed to the early growth of CaLas and the development of symptoms. When the temperature increased from 25 °C to 32 °C, CaLas growth and symptom development in transgenic plants were slower than those in WT controls. RNA-seq analysis of transgenic plants showed that CaLasSDE460 affected multiple biological processes. At 25 °C, transcription activities of the "Protein processing in endoplasmic reticulum" and "Cyanoamino acid metabolism" pathways increased while transcription activities of many pathways decreased at 32 °C. 124 and 53 genes, separately annotated to plant-pathogen interaction and MAPK signaling pathways, showed decreased expression at 32 °C, compared with these (38 for plant-pathogen interaction and 17 for MAPK signaling) at 25 °C. Several important genes (MAPKKK14, HSP70b, NCED3 and WRKY33), remarkably affected by CaLasSDE460, were identified. Totally, our data suggested that CaLasSDE460 participated in the pathogenesis of CaLas through interfering transcription activities of citrus defense response and this interfering was temperature-dependent.
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Affiliation(s)
- Shuai Wang
- Integrative Science Center of Germplasm Creation in Western China (CHONGQING) Science City, Citrus Research Institute, Southwest University/National Citrus Engineering Research Center, Chongqing, People's Republic of China
| | - Meixia Du
- Integrative Science Center of Germplasm Creation in Western China (CHONGQING) Science City, Citrus Research Institute, Southwest University/National Citrus Engineering Research Center, Chongqing, People's Republic of China
| | - Liting Dong
- Integrative Science Center of Germplasm Creation in Western China (CHONGQING) Science City, Citrus Research Institute, Southwest University/National Citrus Engineering Research Center, Chongqing, People's Republic of China
| | - Rongrong Qu
- Integrative Science Center of Germplasm Creation in Western China (CHONGQING) Science City, Citrus Research Institute, Southwest University/National Citrus Engineering Research Center, Chongqing, People's Republic of China
| | - Danlu Ran
- Integrative Science Center of Germplasm Creation in Western China (CHONGQING) Science City, Citrus Research Institute, Southwest University/National Citrus Engineering Research Center, Chongqing, People's Republic of China
| | - Juanjuan Ma
- Integrative Science Center of Germplasm Creation in Western China (CHONGQING) Science City, Citrus Research Institute, Southwest University/National Citrus Engineering Research Center, Chongqing, People's Republic of China
| | - Xuefeng Wang
- Integrative Science Center of Germplasm Creation in Western China (CHONGQING) Science City, Citrus Research Institute, Southwest University/National Citrus Engineering Research Center, Chongqing, People's Republic of China
| | - Lanzhen Xu
- Integrative Science Center of Germplasm Creation in Western China (CHONGQING) Science City, Citrus Research Institute, Southwest University/National Citrus Engineering Research Center, Chongqing, People's Republic of China
| | - Weimin Li
- Key Laboratory for Northern Urban, Agriculture of Ministry of Agriculture and Rural Affairs, Beijing University of Agriculture, Beijing, People's Republic of China
| | - Yongrui He
- Integrative Science Center of Germplasm Creation in Western China (CHONGQING) Science City, Citrus Research Institute, Southwest University/National Citrus Engineering Research Center, Chongqing, People's Republic of China
| | - Xiuping Zou
- Integrative Science Center of Germplasm Creation in Western China (CHONGQING) Science City, Citrus Research Institute, Southwest University/National Citrus Engineering Research Center, Chongqing, People's Republic of China.
- Key Laboratory for Northern Urban, Agriculture of Ministry of Agriculture and Rural Affairs, Beijing University of Agriculture, Beijing, People's Republic of China.
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Cloning of an Albino Mutation of Arabidopsis thaliana Using Mapping-by-Sequencing. Int J Mol Sci 2023; 24:ijms24044196. [PMID: 36835605 PMCID: PMC9964061 DOI: 10.3390/ijms24044196] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2022] [Revised: 02/15/2023] [Accepted: 02/16/2023] [Indexed: 02/22/2023] Open
Abstract
We report the molecular characterization of an ethyl methanesulfonate (EMS)-induced mutation that causes albinism and lethality at the seedling stage in Arabidopsis thaliana. We identified the mutation using a mapping-by-sequencing approach that uses Fisher's exact tests to detect changes in allele frequencies among the seedlings of an F2 mapping population, which had been pooled according to their phenotypes (wild-type or mutant). After purifying genomic DNA from the plants of both pools, the two samples were sequenced using the Illumina HiSeq 2500 next-generation sequencing platform. The bioinformatic analysis allowed us to identify a point mutation that damages a conserved residue at the acceptor site of an intron of the At2g04030 gene, which encodes the chloroplast-localized AtHsp90.5 protein, a member of the HSP90 family of heat shock proteins. Our RNA-seq analysis demonstrates that the new allele alters the splicing of At2g04030 transcripts in multiple ways, leading to massive deregulation of genes encoding plastid-localized proteins. A search for protein-protein interactions using the yeast two-hybrid method allowed us to identify two members of the GrpE superfamily as potential interactors of AtHsp90.5, as has previously been reported for green algae.
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Zhao L, Jia T, Jiao Q, Hu X. Research Progress in J-Proteins in the Chloroplast. Genes (Basel) 2022; 13:genes13081469. [PMID: 36011380 PMCID: PMC9407819 DOI: 10.3390/genes13081469] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2022] [Revised: 08/11/2022] [Accepted: 08/16/2022] [Indexed: 11/16/2022] Open
Abstract
The J-proteins, also called DNAJ-proteins or heat shock protein 40 (HSP40), are one of the famous molecular chaperones. J-proteins, HSP70s and other chaperones work together as constitute ubiquitous types of molecular chaperone complex, which function in a wide variety of physiological processes. J-proteins are widely distributed in major cellular compartments. In the chloroplast of higher plants, around 18 J-proteins and multiple J-like proteins are present; however, the functions of most of them remain unclear. During the last few years, important progress has been made in the research on their roles in plants. There is increasing evidence that the chloroplast J-proteins play essential roles in chloroplast development, photosynthesis, seed germination and stress response. Here, we summarize recent research advances on the roles of J-proteins in the chloroplast, and discuss the open questions that remain in this field.
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Affiliation(s)
- Lu Zhao
- College of Bioscience and Biotechnology, Yangzhou University, Yangzhou 225009, China
| | - Ting Jia
- Joint International Research Laboratory of Agriculture and Agri-Product Safety of the Ministry of Education of China, Yangzhou University, Yangzhou 225009, China
| | - Qingsong Jiao
- College of Bioscience and Biotechnology, Yangzhou University, Yangzhou 225009, China
- Correspondence: (Q.J.); (X.H.)
| | - Xueyun Hu
- College of Bioscience and Biotechnology, Yangzhou University, Yangzhou 225009, China
- Joint International Research Laboratory of Agriculture and Agri-Product Safety of the Ministry of Education of China, Yangzhou University, Yangzhou 225009, China
- Correspondence: (Q.J.); (X.H.)
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6
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Wietrzynski W, Traverso E, Wollman FA, Wostrikoff K. The state of oligomerization of Rubisco controls the rate of synthesis of the Rubisco large subunit in Chlamydomonas reinhardtii. THE PLANT CELL 2021; 33:1706-1727. [PMID: 33625514 PMCID: PMC8254502 DOI: 10.1093/plcell/koab061] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/21/2020] [Accepted: 02/12/2021] [Indexed: 05/22/2023]
Abstract
Ribulose 1,5-bisphosphate carboxylase/oxygenase (Rubisco) is present in all photosynthetic organisms and is a key enzyme for photosynthesis-driven life on Earth. Its most prominent form is a hetero-oligomer in which small subunits (SSU) stabilize the core of the enzyme built from large subunits (LSU), yielding, after a chaperone-assisted multistep assembly process, an LSU8SSU8 hexadecameric holoenzyme. Here we use Chlamydomonas reinhardtii and a combination of site-directed mutants to dissect the multistep biogenesis pathway of Rubisco in vivo. We identify assembly intermediates, in two of which LSU are associated with the RAF1 chaperone. Using genetic and biochemical approaches we further unravel a major regulation process during Rubisco biogenesis, in which LSU translation is controlled by its ability to assemble with the SSU, via the mechanism of control by epistasy of synthesis (CES). Altogether this leads us to propose a model whereby the last assembly intermediate, an LSU8-RAF1 complex, provides the platform for SSU binding to form the Rubisco enzyme, and when SSU is not available, converts to a key regulatory form that exerts negative feedback on the initiation of LSU translation.
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Affiliation(s)
- Wojciech Wietrzynski
- Sorbonne Université, CNRS, Institut de Biologie Physico-Chimique, Unité Mixte de Recherche 7141, 75005 Paris, France
- Department of Molecular Structural Biology, Max Planck Institute of Biochemistry, 82152 Martinsried, Germany
- Helmholtz Pioneer Campus, Helmholtz Zentrum München, 85764 Neuherberg, Germany
| | - Eleonora Traverso
- Sorbonne Université, CNRS, Institut de Biologie Physico-Chimique, Unité Mixte de Recherche 7141, 75005 Paris, France
| | - Francis-André Wollman
- Sorbonne Université, CNRS, Institut de Biologie Physico-Chimique, Unité Mixte de Recherche 7141, 75005 Paris, France
| | - Katia Wostrikoff
- Sorbonne Université, CNRS, Institut de Biologie Physico-Chimique, Unité Mixte de Recherche 7141, 75005 Paris, France
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7
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Bouchnak I, van Wijk KJ. Structure, function, and substrates of Clp AAA+ protease systems in cyanobacteria, plastids, and apicoplasts: A comparative analysis. J Biol Chem 2021; 296:100338. [PMID: 33497624 PMCID: PMC7966870 DOI: 10.1016/j.jbc.2021.100338] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2020] [Revised: 01/22/2021] [Accepted: 01/22/2021] [Indexed: 02/08/2023] Open
Abstract
ATPases Associated with diverse cellular Activities (AAA+) are a superfamily of proteins that typically assemble into hexameric rings. These proteins contain AAA+ domains with two canonical motifs (Walker A and B) that bind and hydrolyze ATP, allowing them to perform a wide variety of different functions. For example, AAA+ proteins play a prominent role in cellular proteostasis by controlling biogenesis, folding, trafficking, and degradation of proteins present within the cell. Several central proteolytic systems (e.g., Clp, Deg, FtsH, Lon, 26S proteasome) use AAA+ domains or AAA+ proteins to unfold protein substrates (using energy from ATP hydrolysis) to make them accessible for degradation. This allows AAA+ protease systems to degrade aggregates and large proteins, as well as smaller proteins, and feed them as linearized molecules into a protease chamber. This review provides an up-to-date and a comparative overview of the essential Clp AAA+ protease systems in Cyanobacteria (e.g., Synechocystis spp), plastids of photosynthetic eukaryotes (e.g., Arabidopsis, Chlamydomonas), and apicoplasts in the nonphotosynthetic apicomplexan pathogen Plasmodium falciparum. Recent progress and breakthroughs in identifying Clp protease structures, substrates, substrate adaptors (e.g., NblA/B, ClpS, ClpF), and degrons are highlighted. We comment on the physiological importance of Clp activity, including plastid biogenesis, proteostasis, the chloroplast Protein Unfolding Response, and metabolism, across these diverse lineages. Outstanding questions as well as research opportunities and priorities to better understand the essential role of Clp systems in cellular proteostasis are discussed.
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Affiliation(s)
- Imen Bouchnak
- Section of Plant Biology, School of Integrative Plant Sciences (SIPS), Cornell University, Ithaca, New York, USA
| | - Klaas J van Wijk
- Section of Plant Biology, School of Integrative Plant Sciences (SIPS), Cornell University, Ithaca, New York, USA.
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8
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Li HM, Schnell D, Theg SM. Protein Import Motors in Chloroplasts: On the Role of Chaperones. THE PLANT CELL 2020; 32:536-542. [PMID: 31932485 PMCID: PMC7054032 DOI: 10.1105/tpc.19.00300] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/25/2019] [Revised: 08/01/2019] [Accepted: 01/08/2020] [Indexed: 05/09/2023]
Affiliation(s)
- Hsou-Min Li
- Institute of Molecular Biology Academia Sinica Taipei 11529, Taiwan
| | - Danny Schnell
- Department of Plant Biology Michigan State University East Lansing, Michigan 48824
| | - Steven M Theg
- Department of Plant Biology University of California Davis, California 95616
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9
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Knopp M, Garg SG, Handrich M, Gould SB. Major Changes in Plastid Protein Import and the Origin of the Chloroplastida. iScience 2020; 23:100896. [PMID: 32088393 PMCID: PMC7038456 DOI: 10.1016/j.isci.2020.100896] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2019] [Revised: 01/09/2020] [Accepted: 02/04/2020] [Indexed: 12/26/2022] Open
Abstract
Core components of plastid protein import and the principle of using N-terminal targeting sequences are conserved across the Archaeplastida, but lineage-specific differences exist. Here we compare, in light of plastid protein import, the response to high-light stress from representatives of the three archaeplastidal groups. Similar to land plants, Chlamydomonas reinhardtii displays a broad response to high-light stress, not observed to the same degree in the glaucophyte Cyanophora paradoxa or the rhodophyte Porphyridium purpureum. We find that only the Chloroplastida encode both Toc75 and Oep80 in parallel and suggest that elaborate high-light stress response is supported by changes in plastid protein import. We propose the origin of a phenylalanine-independent import pathway via Toc75 allowed higher import rates to rapidly service high-light stress, but with the cost of reduced specificity. Changes in plastid protein import define the origin of the green lineage, whose greatest evolutionary success was arguably the colonization of land. Chloroplastida evolved a dual system, Toc75/Oep80, for high throughput protein import Loss of F-based targeting led to dual organelle targeting using a single ambiguous NTS Relaxation of functional constraints allowed a wider Toc/Tic modification A broad response to high-light stress appears unique to Chloroplastida
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Affiliation(s)
- Michael Knopp
- Institute for Molecular Evolution, HH-University Düsseldorf, 40225 Düsseldorf, Germany
| | - Sriram G Garg
- Institute for Molecular Evolution, HH-University Düsseldorf, 40225 Düsseldorf, Germany
| | - Maria Handrich
- Institute for Molecular Evolution, HH-University Düsseldorf, 40225 Düsseldorf, Germany
| | - Sven B Gould
- Institute for Molecular Evolution, HH-University Düsseldorf, 40225 Düsseldorf, Germany.
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10
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Co-Translational Protein Folding and Sorting in Chloroplasts. PLANTS 2020; 9:plants9020214. [PMID: 32045984 PMCID: PMC7076657 DOI: 10.3390/plants9020214] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/17/2020] [Revised: 02/03/2020] [Accepted: 02/04/2020] [Indexed: 01/22/2023]
Abstract
Cells depend on the continuous renewal of their proteome composition during the cell cycle and in order to replace aberrant proteins or to react to changing environmental conditions. In higher eukaryotes, protein synthesis is achieved by up to five million ribosomes per cell. With the fast kinetics of translation, the large number of newly made proteins generates a substantial burden for protein homeostasis and requires a highly orchestrated cascade of factors promoting folding, sorting and final maturation. Several of the involved factors directly bind to translating ribosomes for the early processing of emerging nascent polypeptides and the translocation of ribosome nascent chain complexes to target membranes. In plant cells, protein synthesis also occurs in chloroplasts serving the expression of a relatively small set of 60–100 protein-coding genes. However, most of these proteins, together with nucleus-derived subunits, form central complexes majorly involved in the essential processes of photosynthetic light reaction, carbon fixation, metabolism and gene expression. Biogenesis of these heterogenic complexes adds an additional level of complexity for protein biogenesis. In this review, we summarize the current knowledge about co-translationally binding factors in chloroplasts and discuss their role in protein folding and ribosome translocation to thylakoid membranes.
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11
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Zhang Z, Qu C, Yao R, Nie Y, Xu C, Miao J, Zhong B. The Parallel Molecular Adaptations to the Antarctic Cold Environment in Two Psychrophilic Green Algae. Genome Biol Evol 2020; 11:1897-1908. [PMID: 31106822 PMCID: PMC6628873 DOI: 10.1093/gbe/evz104] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/09/2019] [Indexed: 01/02/2023] Open
Abstract
Psychrophilic green algae from independent phylogenetic lines thrive in the polar extreme environments, but the hypothesis that their psychrophilic characteristics appeared through parallel routes of molecular evolution remains untested. The recent surge of transcriptome data enables large-scale evolutionary analyses to investigate the genetic basis for the adaptations to the Antarctic extreme environment, and the identification of the selective forces that drive molecular evolution is the foundation to understand the strategies of cold adaptation. Here, we conducted transcriptome sequencing of two Antarctic psychrophilic green algae (Chlamydomonas sp. ICE-L and Tetrabaena socialis) and performed positive selection and convergent substitution analyses to investigate their molecular convergence and adaptive strategies against extreme cold conditions. Our results revealed considerable shared positively selected genes and significant evidence of molecular convergence in two Antarctic psychrophilic algae. Significant evidence of positive selection and convergent substitution were detected in genes associated with photosynthetic machinery, multiple antioxidant systems, and several crucial translation elements in Antarctic psychrophilic algae. Our study reveals that the psychrophilic algae possess more stable photosynthetic apparatus and multiple protective mechanisms and provides new clues of parallel adaptive evolution in Antarctic psychrophilic green algae.
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Affiliation(s)
- Zhenhua Zhang
- Jiangsu Key Laboratory for Biodiversity and Biotechnology, College of Life Sciences, Nanjing Normal University, China
| | - Changfeng Qu
- First Institute of Oceanography, Ministry of Natural Resources, Qingdao, China.,Laboratory for Marine Drugs and Bioproducts of Qingdao National Laboratory for Marine Science and Technology, Qingdao, China
| | - Ru Yao
- Jiangsu Key Laboratory for Biodiversity and Biotechnology, College of Life Sciences, Nanjing Normal University, China
| | - Yuan Nie
- Jiangsu Key Laboratory for Biodiversity and Biotechnology, College of Life Sciences, Nanjing Normal University, China
| | - Chenjie Xu
- Jiangsu Key Laboratory for Biodiversity and Biotechnology, College of Life Sciences, Nanjing Normal University, China
| | - Jinlai Miao
- First Institute of Oceanography, Ministry of Natural Resources, Qingdao, China.,Laboratory for Marine Drugs and Bioproducts of Qingdao National Laboratory for Marine Science and Technology, Qingdao, China
| | - Bojian Zhong
- Jiangsu Key Laboratory for Biodiversity and Biotechnology, College of Life Sciences, Nanjing Normal University, China
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12
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Colina F, Carbó M, Meijón M, Cañal MJ, Valledor L. Low UV-C stress modulates Chlamydomonas reinhardtii biomass composition and oxidative stress response through proteomic and metabolomic changes involving novel signalers and effectors. BIOTECHNOLOGY FOR BIOFUELS 2020; 13:110. [PMID: 32577129 PMCID: PMC7305600 DOI: 10.1186/s13068-020-01750-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/05/2020] [Accepted: 06/11/2020] [Indexed: 05/06/2023]
Abstract
BACKGROUND The exposure of microalgae and plants to low UV-C radiation dosages can improve their biomass composition and stress tolerance. Despite UV-C sharing these effects with UV-A/B but at much lower dosages, UV-C sensing and signal mechanisms are still mostly unknown. Thus, we have described and integrated the proteometabolomic and physiological changes occurring in Chlamydomonas reinhardtii-a simple Plantae model-into the first 24 h after a short and low-intensity UV-C irradiation in order to reconstruct the microalgae response system to this stress. RESULTS The microalgae response was characterized by increased redox homeostasis, ROS scavenging and protein damage repair/avoidance elements. These processes were upregulated along with others related to the modulation of photosynthetic electron flux, carbon fixation and C/N metabolism. These changes, attributed to either direct UV-C-, ROS- or redox unbalances-associated damage, trigger a response process involving novel signaling intermediaries and effectors such as the translation modulator FAP204, a PP2A-like protein and a novel DYRK kinase. These elements were found linked to the modulation of Chlamydomonas biomass composition (starch accumulation) and proliferation, within an UV-C response probably modulated by different epigenetic factors. CONCLUSION Chosen multiomics integration approach was able to describe many fast changes, including biomass composition and ROS stress tolerance, as a response to a low-intensity UV-C stress. Moreover, the employed omics and systems biology approach placed many previously unidentified protein and metabolites at the center of these changes. These elements would be promising targets for the characterization of this stress response in microalgae and plants and the engineering of more productive microalgae strains.
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Affiliation(s)
- Francisco Colina
- Plant Physiology, Department of Organisms and Systems Biology and University Institute of Biotechnology of Asturias (IUBA), University of Oviedo, Oviedo, Spain
| | - María Carbó
- Plant Physiology, Department of Organisms and Systems Biology and University Institute of Biotechnology of Asturias (IUBA), University of Oviedo, Oviedo, Spain
| | - Mónica Meijón
- Plant Physiology, Department of Organisms and Systems Biology and University Institute of Biotechnology of Asturias (IUBA), University of Oviedo, Oviedo, Spain
| | - María Jesús Cañal
- Plant Physiology, Department of Organisms and Systems Biology and University Institute of Biotechnology of Asturias (IUBA), University of Oviedo, Oviedo, Spain
| | - Luis Valledor
- Plant Physiology, Department of Organisms and Systems Biology and University Institute of Biotechnology of Asturias (IUBA), University of Oviedo, Oviedo, Spain
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13
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Theis J, Lang J, Spaniol B, Ferté S, Niemeyer J, Sommer F, Zimmer D, Venn B, Mehr SF, Mühlhaus T, Wollman FA, Schroda M. The Chlamydomonas deg1c Mutant Accumulates Proteins Involved in High Light Acclimation. PLANT PHYSIOLOGY 2019; 181:1480-1497. [PMID: 31604811 PMCID: PMC6878023 DOI: 10.1104/pp.19.01052] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/01/2019] [Accepted: 09/27/2019] [Indexed: 05/18/2023]
Abstract
Degradation of periplasmic proteins (Deg)/high temperature requirement A (HtrA) proteases are ATP-independent Ser endopeptidases that perform key aspects of protein quality control in all domains of life. Here, we characterized Chlamydomonas reinhardtii DEG1C, which together with DEG1A and DEG1B is orthologous to Arabidopsis (Arabidopsis thaliana) Deg1 in the thylakoid lumen. We show that DEG1C is localized to the stroma and the periphery of thylakoid membranes. Purified DEG1C exhibited high proteolytic activity against unfolded model substrates and its activity increased with temperature and pH. DEG1C forms monomers, trimers, and hexamers that are in dynamic equilibrium. DEG1C protein levels increased upon nitrogen, sulfur, and phosphorus starvation; under heat, oxidative, and high light stress; and when Sec-mediated protein translocation was impaired. DEG1C depletion was not associated with any obvious aberrant phenotypes under nonstress conditions, high light exposure, or heat stress. However, quantitative shotgun proteomics revealed differences in the abundance of 307 proteins between a deg1c knock-out mutant and the wild type under nonstress conditions. Among the 115 upregulated proteins are PSII biogenesis factors, FtsH proteases, and proteins normally involved in high light responses, including the carbon dioxide concentrating mechanism, photorespiration, antioxidant defense, and photoprotection. We propose that the lack of DEG1C activity leads to a physiological state of the cells resembling that induced by high light intensities and therefore triggers high light protection responses.
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Affiliation(s)
- Jasmine Theis
- Molekulare Biotechnologie & Systembiologie, Technische Universität Kaiserslautern, Paul-Ehrlich D-67663 Kaiserslautern, Germany
| | - Julia Lang
- Molekulare Biotechnologie & Systembiologie, Technische Universität Kaiserslautern, Paul-Ehrlich D-67663 Kaiserslautern, Germany
| | - Benjamin Spaniol
- Molekulare Biotechnologie & Systembiologie, Technische Universität Kaiserslautern, Paul-Ehrlich D-67663 Kaiserslautern, Germany
| | - Suzanne Ferté
- Laboratoire de Physiologie Membranaire et Moléculaire du Chloroplaste, Institut de Biologie Physico-Chimique, UMR CNRS/UPMC 7141, Paris, France
| | - Justus Niemeyer
- Molekulare Biotechnologie & Systembiologie, Technische Universität Kaiserslautern, Paul-Ehrlich D-67663 Kaiserslautern, Germany
| | - Frederik Sommer
- Molekulare Biotechnologie & Systembiologie, Technische Universität Kaiserslautern, Paul-Ehrlich D-67663 Kaiserslautern, Germany
| | - David Zimmer
- Molekulare Biotechnologie & Systembiologie, Technische Universität Kaiserslautern, Paul-Ehrlich D-67663 Kaiserslautern, Germany
| | - Benedikt Venn
- Molekulare Biotechnologie & Systembiologie, Technische Universität Kaiserslautern, Paul-Ehrlich D-67663 Kaiserslautern, Germany
| | - Shima Farazandeh Mehr
- Molekulare Biotechnologie & Systembiologie, Technische Universität Kaiserslautern, Paul-Ehrlich D-67663 Kaiserslautern, Germany
| | - Timo Mühlhaus
- Molekulare Biotechnologie & Systembiologie, Technische Universität Kaiserslautern, Paul-Ehrlich D-67663 Kaiserslautern, Germany
| | - Francis-André Wollman
- Laboratoire de Physiologie Membranaire et Moléculaire du Chloroplaste, Institut de Biologie Physico-Chimique, UMR CNRS/UPMC 7141, Paris, France
| | - Michael Schroda
- Molekulare Biotechnologie & Systembiologie, Technische Universität Kaiserslautern, Paul-Ehrlich D-67663 Kaiserslautern, Germany
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14
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Biebl MM, Buchner J. Structure, Function, and Regulation of the Hsp90 Machinery. Cold Spring Harb Perspect Biol 2019; 11:cshperspect.a034017. [PMID: 30745292 DOI: 10.1101/cshperspect.a034017] [Citation(s) in RCA: 166] [Impact Index Per Article: 33.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Heat shock protein 90 (Hsp90) is a molecular chaperone involved in the maturation of a plethora of substrates ("clients"), including protein kinases, transcription factors, and E3 ubiquitin ligases, positioning Hsp90 as a central regulator of cellular proteostasis. Hsp90 undergoes large conformational changes during its ATPase cycle. The processing of clients by cytosolic Hsp90 is assisted by a cohort of cochaperones that affect client recruitment, Hsp90 ATPase function or conformational rearrangements in Hsp90. Because of the importance of Hsp90 in regulating central cellular pathways, strategies for the pharmacological inhibition of the Hsp90 machinery in diseases such as cancer and neurodegeneration are being developed. In this review, we summarize recent structural and mechanistic progress in defining the function of organelle-specific and cytosolic Hsp90, including the impact of individual cochaperones on the maturation of specific clients and complexes with clients as well as ways of exploiting Hsp90 as a drug target.
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Affiliation(s)
- Maximilian M Biebl
- Center for Integrated Protein Science, Department of Chemistry, Technische Universität München, D-85748 Garching, Germany
| | - Johannes Buchner
- Center for Integrated Protein Science, Department of Chemistry, Technische Universität München, D-85748 Garching, Germany
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15
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Rohr M, Ries F, Herkt C, Gotsmann VL, Westrich LD, Gries K, Trösch R, Christmann J, Chaux-Jukic F, Jung M, Zimmer D, Mühlhaus T, Sommer F, Schroda M, Keller S, Möhlmann T, Willmund F. The Role of Plastidic Trigger Factor Serving Protein Biogenesis in Green Algae and Land Plants. PLANT PHYSIOLOGY 2019; 179:1093-1110. [PMID: 30651302 PMCID: PMC6393800 DOI: 10.1104/pp.18.01252] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/16/2018] [Accepted: 01/07/2019] [Indexed: 05/07/2023]
Abstract
Biochemical processes in chloroplasts are important for virtually all life forms. Tight regulation of protein homeostasis and the coordinated assembly of protein complexes, composed of both imported and locally synthesized subunits, are vital to plastid functionality. Protein biogenesis requires the action of cotranslationally acting molecular chaperones. One such chaperone is trigger factor (TF), which is known to cotranslationally bind most newly synthesized proteins in bacteria, thereby assisting their correct folding and maturation. However, how these processes are regulated in chloroplasts remains poorly understood. We report here functional investigation of chloroplast-localized TF (TIG1) in the green alga (Chlamydomonas reinhardtii) and the vascular land plant Arabidopsis (Arabidopsis thaliana). We show that chloroplastic TIG1 evolved as a specialized chaperone. Unlike other plastidic chaperones that are functionally interchangeable with their prokaryotic counterpart, TIG1 was not able to complement the broadly acting ortholog in Escherichia coli. Whereas general chaperone properties such as the prevention of aggregates or substrate recognition seems to be conserved between bacterial and plastidic TFs, plant TIG1s differed by associating with only a relatively small population of translating ribosomes. Furthermore, a reduction of plastidic TIG1 levels leads to deregulated protein biogenesis at the expense of increased translation, thereby disrupting the chloroplast energy household. This suggests a central role of TIG1 in protein biogenesis in the chloroplast.
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Affiliation(s)
- Marina Rohr
- Molecular Genetics of Eukaryotes, University of Kaiserslautern, Paul-Ehrlich-Strasse 23, 67663 Kaiserslautern, Germany
| | - Fabian Ries
- Molecular Genetics of Eukaryotes, University of Kaiserslautern, Paul-Ehrlich-Strasse 23, 67663 Kaiserslautern, Germany
| | - Claudia Herkt
- Molecular Genetics of Eukaryotes, University of Kaiserslautern, Paul-Ehrlich-Strasse 23, 67663 Kaiserslautern, Germany
| | - Vincent Leon Gotsmann
- Molecular Genetics of Eukaryotes, University of Kaiserslautern, Paul-Ehrlich-Strasse 23, 67663 Kaiserslautern, Germany
| | - Lisa Désirée Westrich
- Molecular Genetics of Eukaryotes, University of Kaiserslautern, Paul-Ehrlich-Strasse 23, 67663 Kaiserslautern, Germany
| | - Karin Gries
- Molecular Genetics of Eukaryotes, University of Kaiserslautern, Paul-Ehrlich-Strasse 23, 67663 Kaiserslautern, Germany
| | - Raphael Trösch
- Molecular Genetics of Eukaryotes, University of Kaiserslautern, Paul-Ehrlich-Strasse 23, 67663 Kaiserslautern, Germany
| | - Jens Christmann
- Molecular Genetics of Eukaryotes, University of Kaiserslautern, Paul-Ehrlich-Strasse 23, 67663 Kaiserslautern, Germany
| | | | - Martin Jung
- Medical Biochemistry and Molecular Biology, Building 44, Saarland University, 66421 Homburg, Germany
| | - David Zimmer
- Computational Systems Biology, University of Kaiserslautern, Paul-Ehrlich-Strasse 23, 67663 Kaiserslautern, Germany
| | - Timo Mühlhaus
- Computational Systems Biology, University of Kaiserslautern, Paul-Ehrlich-Strasse 23, 67663 Kaiserslautern, Germany
| | - Frederik Sommer
- Molecular Biotechnology and Systems Biology, University of Kaiserslautern, Paul-Ehrlich-Strasse 23, 67663 Kaiserslautern, Germany
| | - Michael Schroda
- Molecular Biotechnology and Systems Biology, University of Kaiserslautern, Paul-Ehrlich-Strasse 23, 67663 Kaiserslautern, Germany
| | - Sandro Keller
- Molecular Biophysics, University of Kaiserslautern, Paul-Ehrlich-Strasse 23, 67663 Kaiserslautern, Germany
| | - Torsten Möhlmann
- Plant Physiology, University of Kaiserslautern, Paul-Ehrlich Strasse 22, 67663 Kaiserslautern, Germany
| | - Felix Willmund
- Molecular Genetics of Eukaryotes, University of Kaiserslautern, Paul-Ehrlich-Strasse 23, 67663 Kaiserslautern, Germany
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16
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Verma AK, Tamadaddi C, Tak Y, Lal SS, Cole SJ, Hines JK, Sahi C. The expanding world of plant J-domain proteins. CRITICAL REVIEWS IN PLANT SCIENCES 2019; 38:382-400. [PMID: 33223602 PMCID: PMC7678915 DOI: 10.1080/07352689.2019.1693716] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Plants maintain cellular proteostasis during different phases of growth and development despite a barrage of biotic and abiotic stressors in an ever-changing environment. This requires a collaborative effort of a cadre of molecular chaperones. Hsp70s and their obligate co-chaperones, J-domain proteins (JDPs), are arguably the most ubiquitous and formidable components of the cellular chaperone network, facilitating numerous and diverse cellular processes and allowing survival under a plethora of stressful conditions. JDPs are also among the most versatile chaperones. Compared to Hsp70s, the number of JDP-encoding genes has proliferated, suggesting the emergence of highly complex Hsp70-JDP networks, particularly in plants. Recent studies indicate that besides the increase in the number of JDP encoding genes; regulatory differences, neo- and sub-functionalization, and inter- and intra-class combinatorial interactions, is rapidly expanding the repertoire of Hsp70-JDP systems. This results in highly robust and functionally diverse chaperone networks in plants. Here, we review the current status of plant JDP research and discuss how the paradigm shift in the field can be exploited toward a better understanding of JDP function and evolution.
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Affiliation(s)
- Amit K. Verma
- Department of Biological Sciences, Indian Institute of Science Education and Research Bhopal, Bhopal, India
| | - Chetana Tamadaddi
- Department of Biological Sciences, Indian Institute of Science Education and Research Bhopal, Bhopal, India
| | - Yogesh Tak
- Department of Biological Sciences, Indian Institute of Science Education and Research Bhopal, Bhopal, India
| | - Silviya S. Lal
- Department of Biological Sciences, Indian Institute of Science Education and Research Bhopal, Bhopal, India
| | - Sierra J. Cole
- Department of Chemistry, Lafayette College, Easton, PA, USA
| | | | - Chandan Sahi
- Department of Biological Sciences, Indian Institute of Science Education and Research Bhopal, Bhopal, India
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17
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Su PH, Lin HY, Lai YH. Two Arabidopsis Chloroplast GrpE Homologues Exhibit Distinct Biological Activities and Can Form Homo- and Hetero-Oligomers. FRONTIERS IN PLANT SCIENCE 2019; 10:1719. [PMID: 32038688 PMCID: PMC6987454 DOI: 10.3389/fpls.2019.01719] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/30/2019] [Accepted: 12/06/2019] [Indexed: 05/15/2023]
Abstract
Flowering plants have evolved two distinct clades of chloroplast GrpE homologues (CGEs), which are the nucleotide exchange factor for Hsp70. In Arabidopsis, they are named AtCGE1 (At5g17710) and AtCGE2 (At1g36390). Characterization of their corresponding T-DNA insertion mutants revealed that there is no visible change in phenotype except a defect in protein import in an AtCGE2-knockout mutant under normal growth conditions. However, the embryo development of an AtCGE1-knockout mutant was arrested early at the globular stage. An AtCGE1-knockdown mutant, harboring a T-DNA insertion in the 5'-UTR region, exhibited growth retardation and protein import defect, and its mutant phenotypes became more severe when AtCGE2 was further knocked out. Sub-organellar distribution implied that AtCGE2 might be important for membrane biology due to its preferential association with chloroplast membranes. Biochemical studies and complementation tests showed that only AtCGE1, but not AtCGE2, can effectively rescue the heat-sensitive phenotype of Escherichia coli grpE mutant and robustly stimulate the refolding of denatured luciferase by DnaK. Interestingly, AtCGE1 and AtCGE2 are tending to form heterocomplexes, which exhibit comparable co-chaperone activity to AtCGE1 homocomplexes. Our data indicate that AtCGE1 is the principle functional homologue of GrpE. The possibility that AtCGE2 has a subsidiary or regulatory function through homo- and/or hetero-oligomerization is discussed.
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Affiliation(s)
- Pai-Hsiang Su
- Agricultural Biotechnology Research Center, Academia Sinica, Taipei, Taiwan
- Biotechnology Center in Southern Taiwan, Academia Sinica, Tainan, Taiwan
- *Correspondence: Pai-Hsiang Su,
| | - Hsuan-Yu Lin
- Biotechnology Center in Southern Taiwan, Academia Sinica, Tainan, Taiwan
| | - Yen-Hsun Lai
- Biotechnology Center in Southern Taiwan, Academia Sinica, Tainan, Taiwan
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18
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Nyakundi DO, Bentley SJ, Boshoff A. Hsp70 Escort Protein: More Than a Regulator of Mitochondrial Hsp70. CURR PROTEOMICS 2018. [DOI: 10.2174/1570164615666180713104919] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Hsp70 members occupy a central role in proteostasis and are found in different eukaryotic
cellular compartments. The mitochondrial Hsp70/J-protein machinery performs multiple functions vital
for the proper functioning of the mitochondria, including forming part of the import motor that
transports proteins from the cytosol into the matrix and inner membrane, and subsequently folds these
proteins in the mitochondria. However, unlike other Hsp70s, mitochondrial Hsp70 (mtHsp70) has the
propensity to self-aggregate, accumulating as insoluble aggregates. The self-aggregation of mtHsp70 is
caused by both interdomain and intramolecular communication within the ATPase and linker domains.
Since mtHsp70 is unable to fold itself into an active conformation, it requires an Hsp70 escort protein
(Hep) to both inhibit self-aggregation and promote the correct folding. Hep1 orthologues are present in
the mitochondria of many eukaryotic cells but are absent in prokaryotes. Hep1 proteins are relatively
small and contain a highly conserved zinc-finger domain with one tetracysteine motif that is essential
for binding zinc ions and maintaining the function and solubility of the protein. The zinc-finger domain
lies towards the C-terminus of Hep1 proteins, with very little conservation outside of this domain.
Other than maintaining mtHsp70 in a functional state, Hep1 proteins play a variety of other roles in the
cell and have been proposed to function as both chaperones and co-chaperones. The cellular
localisation and some of the functions are often speculative and are not common to all Hep1 proteins
analysed to date.
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Affiliation(s)
- David O. Nyakundi
- Biotechnology Innovation Centre, Rhodes University, Grahamstown 6140, South Africa
| | - Stephen J. Bentley
- Biotechnology Innovation Centre, Rhodes University, Grahamstown 6140, South Africa
| | - Aileen Boshoff
- Biotechnology Innovation Centre, Rhodes University, Grahamstown 6140, South Africa
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19
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Rampuria S, Bag P, Rogan CJ, Sharma A, Gassmann W, Kirti PB. Pathogen-induced AdDjSKI of the wild peanut, Arachis diogoi, potentiates tolerance of multiple stresses in E. coli and tobacco. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2018; 272:62-74. [PMID: 29807607 DOI: 10.1016/j.plantsci.2018.03.033] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/08/2017] [Revised: 03/25/2018] [Accepted: 03/31/2018] [Indexed: 06/08/2023]
Abstract
A gene encoding a serine-rich DnaJIII protein called AdDjSKI that has a 4Fe-4S cluster domain was found to be differentially upregulated in the wild peanut, Arachis diogoi in its resistance responses against the late leaf spot causing fungal pathogen Phaeoisariopsis personata when compared with the cultivated peanut, Arachis hypogaea. AdDjSKI is induced in multiple stress conditions in A. diogoi. Recombinant E. coli cells expressing AdDjSKI showed better growth kinetics when compared with vector control cells under salinity, osmotic, acidic and alkaline stress conditions. Overexpression of this type three J-protein potentiates not only abiotic stress tolerance in Nicotiana tabacum var. Samsun, but also enhances its disease resistance against the phytopathogenic fungi Phytophthora parasitica pv nicotianae and Sclerotinia sclerotiorum. In the present study we show transcriptional upregulation of APX, Mn-SOD and HSP70 under heat stress and increased transcripts of PR genes in response to fungal infection. This transmembrane-domain-containing J protein displays punctate localization in chloroplasts. AdDjSKI appears to ensure proper folding of proteins associated with the photosynthetic machinery under stress.
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Affiliation(s)
- Sakshi Rampuria
- Department of Plant Sciences, School of Life Sciences, University of Hyderabad, Hyderabad, Telangana, India
| | - Pushan Bag
- Department of Plant Sciences, School of Life Sciences, University of Hyderabad, Hyderabad, Telangana, India
| | - Conner J Rogan
- Division of Biological Sciences, Christopher S. Bond Life Sciences Center and Interdisciplinary Plant Group, University of Missouri, Columbia, MO, USA
| | - Akanksha Sharma
- Department of Plant Sciences, School of Life Sciences, University of Hyderabad, Hyderabad, Telangana, India
| | - Walter Gassmann
- Division of Plant Sciences, Christopher S. Bond Life Sciences Center and Interdisciplinary Plant Group, University of Missouri, Columbia, MO, USA
| | - P B Kirti
- Department of Plant Sciences, School of Life Sciences, University of Hyderabad, Hyderabad, Telangana, India.
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20
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Traewachiwiphak S, Yokthongwattana C, Ves-Urai P, Charoensawan V, Yokthongwattana K. Gene expression and promoter characterization of heat-shock protein 90B gene (HSP90B) in the model unicellular green alga Chlamydomonas reinhardtii. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2018; 272:107-116. [PMID: 29807581 DOI: 10.1016/j.plantsci.2018.04.010] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/30/2017] [Revised: 03/11/2018] [Accepted: 04/12/2018] [Indexed: 06/08/2023]
Abstract
Molecular chaperones or heat shock proteins are a large protein family with important functions in every cellular organism. Among all types of the heat shock proteins, information on the ER-localized HSP90 protein (HSP90B) and its encoding gene is relatively scarce in the literature, especially in photosynthetic organisms. In this study, expression profiles as well as promoter sequence of the HSP90B gene were investigated in the model green alga Chlamydomonas reinhardtii. We have found that HSP90B is strongly induced by heat and ER stresses, while other short-term exposure to abiotic stresses, such as salinity, dark-to-light transition or light stress does not appear to affect the expression. Promoter truncation analysis as well as chromatin immunoprecipitation using the antibodies recognizing histone H3 and acetylated histone H3, revealed a putative core constitutive promoter sequence between -1 to -253 bp from the transcription start site. Our results also suggested that the nucleotides upstream of the core promoter may contain repressive elements such as putative repressor binding site(s).
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Affiliation(s)
- Somchoke Traewachiwiphak
- Department of Biochemistry, Faculty of Science, Mahidol University, 272 Rama 6 Rd., Bangkok 10400, Thailand; Center for Excellence in Protein and Enzyme Technology, Faculty of Science, Mahidol University, 272 Rama 6 Rd., Bangkok 10400, Thailand
| | - Chotika Yokthongwattana
- Department of Biochemistry, Faculty of Science, Kasetsart University, 50 Ngamwongwan Rd., Bangkok 10900, Thailand
| | - Parthompong Ves-Urai
- Department of Biochemistry, Faculty of Science, Mahidol University, 272 Rama 6 Rd., Bangkok 10400, Thailand
| | - Varodom Charoensawan
- Department of Biochemistry, Faculty of Science, Mahidol University, 272 Rama 6 Rd., Bangkok 10400, Thailand; Integrative Computational BioScience (ICBS) Center, Mahidol University, Nakhon Pathom, Thailand; Systems Biology of Diseases Research Unit, Faculty of Science, Mahidol University, Bangkok, Thailand
| | - Kittisak Yokthongwattana
- Department of Biochemistry, Faculty of Science, Mahidol University, 272 Rama 6 Rd., Bangkok 10400, Thailand; Center for Excellence in Protein and Enzyme Technology, Faculty of Science, Mahidol University, 272 Rama 6 Rd., Bangkok 10400, Thailand.
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21
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Jiang T, Oh ES, Bonea D, Zhao R. HSP90C interacts with PsbO1 and facilitates its thylakoid distribution from chloroplast stroma in Arabidopsis. PLoS One 2017; 12:e0190168. [PMID: 29281724 PMCID: PMC5745004 DOI: 10.1371/journal.pone.0190168] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2017] [Accepted: 12/08/2017] [Indexed: 11/29/2022] Open
Abstract
Arabidopsis plastidic HSP90C is an HSP90 family molecular chaperone that is required for chloroplast development and function. To understand the mechanism of action of HSP90C within the chloroplast, we conducted a yeast two-hybrid screening and revealed it interacts directly with the photosystem II extrinsic protein PsbO1, which performs a canonical function in the thylakoid lumen. To understand the biological significance of HSP90C-PsbO1 interaction, we investigated the role of HSP90C in modulating the stromal and thylakoid distribution of PsbO1GFP fusion protein. Fusion to GFP significantly delays the PsbO1 thylakoid transport and induces a variegation phenotype. Overexpression of HSP90C promotes the thylakoid distribution of PsbO1GFP and alleviates the leaf variegation. By tracking the chloroplast maturation during photomorphogenesis, we observed PsbO1GFP tends to form distinct fluorescent clusters within the stroma with delayed thylakoid membrane biogenesis, while HSP90C overexpression corrects these adverse effects. We also demonstrated that active HSP90C function is specifically required for stable accumulation of mature PsbO1GFP in thylakoid by using specific inhibitor geldanamycin. This study therefore not only identified novel HSP90C interactors, but also reports for the first time that PsbO1 enroute from the cytoplasm to thylakoid lumen is tightly regulated by the HSP90C chaperone complex in plastid stroma; whereas the proper HSP90C homeostasis is also critical for chloroplast maturation and function.
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Affiliation(s)
- Tim Jiang
- Departments of Biological Sciences and Cell & Systems Biology, University of Toronto, Toronto, Ontario, Canada
| | - Edward Saehong Oh
- Departments of Biological Sciences and Cell & Systems Biology, University of Toronto, Toronto, Ontario, Canada
| | - Diana Bonea
- Departments of Biological Sciences and Cell & Systems Biology, University of Toronto, Toronto, Ontario, Canada
| | - Rongmin Zhao
- Departments of Biological Sciences and Cell & Systems Biology, University of Toronto, Toronto, Ontario, Canada
- * E-mail:
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22
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Salesse C, Sharwood R, Sakamoto W, Stern D. The Rubisco Chaperone BSD2 May Regulate Chloroplast Coverage in Maize Bundle Sheath Cells. PLANT PHYSIOLOGY 2017; 175:1624-1633. [PMID: 29089394 PMCID: PMC5717744 DOI: 10.1104/pp.17.01346] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/18/2017] [Accepted: 10/27/2017] [Indexed: 05/04/2023]
Abstract
In maize (Zea mays), Bundle Sheath Defective2 (BSD2) plays an essential role in Rubisco biogenesis and is required for correct bundle sheath (BS) cell differentiation. Yet, BSD2 RNA and protein levels are similar in mesophyll (M) and BS chloroplasts, although Rubisco accumulates only in BS chloroplasts. This raises the possibility of additional BSD2 roles in cell development. To test this hypothesis, transgenic lines were created that overexpress and underexpress BSD2 in both BS and M cells, driven by the cell type-specific Rubisco Small Subunit (RBCS) or Phosphoenolpyruvate Carboxylase (PEPC) promoters or the ubiquitin promoter. Genetic crosses showed that each of the transgenes could complement Rubisco deficiency and seedling lethality conferred by the bsd2 mutation. This was unexpected, as RBCS-BSD2 lines lacked BSD2 in M chloroplasts and PEPC-BSD2 lines expressed half the wild-type BSD2 level in BS chloroplasts. We conclude that BSD2 does not play a vital role in M cells and that BS BSD2 is in excess of requirements for Rubisco accumulation. BSD2 levels did affect chloroplast coverage in BS cells. In PEPC-BSD2 lines, chloroplast coverage decreased 30% to 50%, whereas lines with increased BSD2 content exhibited a 25% increase. This suggests that BSD2 has an ancillary role in BS cells related to chloroplast size. Gas exchange showed decreased photosynthetic rates in PEPC-BSD2 lines despite restored Rubisco function, correlating with reduced chloroplast coverage and pointing to CO2 diffusion changes. Conversely, increased chloroplast coverage did not result in increased Rubisco abundance or photosynthetic rates. This suggests another limitation beyond chloroplast volume, most likely Rubisco biogenesis and/or turnover rates.
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Affiliation(s)
- Coralie Salesse
- Boyce Thompson Institute, Cornell University, Ithaca, New York 14853
| | - Robert Sharwood
- Research School of Biology, Australian National University, Canberra, Australian Capital Territory 0200, Australia
| | - Wataru Sakamoto
- Institute of Plant Science and Resources, Okayama University, Kurashiki, Okayama 710-0046, Japan
| | - David Stern
- Boyce Thompson Institute, Cornell University, Ithaca, New York 14853
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23
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Rütgers M, Muranaka LS, Mühlhaus T, Sommer F, Thoms S, Schurig J, Willmund F, Schulz-Raffelt M, Schroda M. Substrates of the chloroplast small heat shock proteins 22E/F point to thermolability as a regulative switch for heat acclimation in Chlamydomonas reinhardtii. PLANT MOLECULAR BIOLOGY 2017; 95:579-591. [PMID: 29094278 PMCID: PMC5700999 DOI: 10.1007/s11103-017-0672-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/06/2017] [Accepted: 10/16/2017] [Indexed: 05/06/2023]
Abstract
We have identified 39 proteins that interact directly or indirectly with high confidence with chloroplast HSP22E/F under heat stress thus revealing chloroplast processes affected by heat. Under conditions promoting protein unfolding, small heat shock proteins (sHsps) prevent the irreversible aggregation of unfolding proteins by integrating into forming aggregates. Aggregates containing sHsps facilitate the access of Hsp70 and ClpB/Hsp104 chaperones, which in ATP-dependent reactions disentangle individual proteins from the aggregates and assist in their refolding to the native state. Chlamydomonas reinhardtii encodes eight different sHsps (HSP22A to H). The goal of this work was to identify chloroplast-targeted sHsps in Chlamydomonas and to obtain a comprehensive list of the substrates with which they interact during heat stress in order to understand which chloroplast processes are disturbed under heat stress. We show that HSP22E and HSP22F are major chloroplast-targeted sHsps that have emerged from a recent gene duplication event resulting from the ongoing diversification of sHsps in the Volvocales. HSP22E/F strongly accumulate during heat stress and form high molecular mass complexes. Using differential immunoprecipitation, mass spectrometry and a stringent filtering algorithm we identified 39 proteins that with high-confidence interact directly or indirectly with HSP22E/F under heat stress. We propose that the apparent thermolability of several of these proteins might be a desired trait as part of a mechanism enabling Chlamydomonas chloroplasts to rapidly react to thermal stress.
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Affiliation(s)
- Mark Rütgers
- Molekulare Biotechnologie & Systembiologie, TU Kaiserslautern, Paul-Ehrlich Straße 23, 67663, Kaiserslautern, Germany
| | - Ligia Segatto Muranaka
- Molekulare Biotechnologie & Systembiologie, TU Kaiserslautern, Paul-Ehrlich Straße 23, 67663, Kaiserslautern, Germany
| | - Timo Mühlhaus
- Molekulare Biotechnologie & Systembiologie, TU Kaiserslautern, Paul-Ehrlich Straße 23, 67663, Kaiserslautern, Germany
| | - Frederik Sommer
- Molekulare Biotechnologie & Systembiologie, TU Kaiserslautern, Paul-Ehrlich Straße 23, 67663, Kaiserslautern, Germany
| | - Sylvia Thoms
- Molekulare Biotechnologie & Systembiologie, TU Kaiserslautern, Paul-Ehrlich Straße 23, 67663, Kaiserslautern, Germany
| | - Juliane Schurig
- Molekulare Biotechnologie & Systembiologie, TU Kaiserslautern, Paul-Ehrlich Straße 23, 67663, Kaiserslautern, Germany
| | - Felix Willmund
- Molekulare Biotechnologie & Systembiologie, TU Kaiserslautern, Paul-Ehrlich Straße 23, 67663, Kaiserslautern, Germany
| | - Miriam Schulz-Raffelt
- Molekulare Biotechnologie & Systembiologie, TU Kaiserslautern, Paul-Ehrlich Straße 23, 67663, Kaiserslautern, Germany
| | - Michael Schroda
- Molekulare Biotechnologie & Systembiologie, TU Kaiserslautern, Paul-Ehrlich Straße 23, 67663, Kaiserslautern, Germany.
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Salesse C, Sharwood R, Sakamoto W, Stern D. The Rubisco Chaperone BSD2 May Regulate Chloroplast Coverage in Maize Bundle Sheath Cells. PLANT PHYSIOLOGY 2017. [PMID: 29089394 DOI: 10.1104/pp.17.0134] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
In maize (Zea mays), Bundle Sheath Defective2 (BSD2) plays an essential role in Rubisco biogenesis and is required for correct bundle sheath (BS) cell differentiation. Yet, BSD2 RNA and protein levels are similar in mesophyll (M) and BS chloroplasts, although Rubisco accumulates only in BS chloroplasts. This raises the possibility of additional BSD2 roles in cell development. To test this hypothesis, transgenic lines were created that overexpress and underexpress BSD2 in both BS and M cells, driven by the cell type-specific Rubisco Small Subunit (RBCS) or Phosphoenolpyruvate Carboxylase (PEPC) promoters or the ubiquitin promoter. Genetic crosses showed that each of the transgenes could complement Rubisco deficiency and seedling lethality conferred by the bsd2 mutation. This was unexpected, as RBCS-BSD2 lines lacked BSD2 in M chloroplasts and PEPC-BSD2 lines expressed half the wild-type BSD2 level in BS chloroplasts. We conclude that BSD2 does not play a vital role in M cells and that BS BSD2 is in excess of requirements for Rubisco accumulation. BSD2 levels did affect chloroplast coverage in BS cells. In PEPC-BSD2 lines, chloroplast coverage decreased 30% to 50%, whereas lines with increased BSD2 content exhibited a 25% increase. This suggests that BSD2 has an ancillary role in BS cells related to chloroplast size. Gas exchange showed decreased photosynthetic rates in PEPC-BSD2 lines despite restored Rubisco function, correlating with reduced chloroplast coverage and pointing to CO2 diffusion changes. Conversely, increased chloroplast coverage did not result in increased Rubisco abundance or photosynthetic rates. This suggests another limitation beyond chloroplast volume, most likely Rubisco biogenesis and/or turnover rates.
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Affiliation(s)
- Coralie Salesse
- Boyce Thompson Institute, Cornell University, Ithaca, New York 14853
| | - Robert Sharwood
- Research School of Biology, Australian National University, Canberra, Australian Capital Territory 0200, Australia
| | - Wataru Sakamoto
- Institute of Plant Science and Resources, Okayama University, Kurashiki, Okayama 710-0046, Japan
| | - David Stern
- Boyce Thompson Institute, Cornell University, Ithaca, New York 14853
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25
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Ries F, Carius Y, Rohr M, Gries K, Keller S, Lancaster CRD, Willmund F. Structural and molecular comparison of bacterial and eukaryotic trigger factors. Sci Rep 2017; 7:10680. [PMID: 28878399 PMCID: PMC5587573 DOI: 10.1038/s41598-017-10625-2] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2017] [Accepted: 08/11/2017] [Indexed: 12/04/2022] Open
Abstract
A considerably small fraction of approximately 60–100 proteins of all chloroplast proteins are encoded by the plastid genome. Many of these proteins are major subunits of complexes with central functions within plastids. In comparison with other subcellular compartments and bacteria, many steps of chloroplast protein biogenesis are not well understood. We report here on the first study of chloroplast-localised trigger factor. In bacteria, this molecular chaperone is known to associate with translating ribosomes to facilitate the folding of newly synthesized proteins. Chloroplast trigger factors of the unicellular green algae Chlamydomonas reinhardtii and the vascular land plant Arabidopsis thaliana were characterized by biophysical and structural methods and compared to the Escherichia coli isoform. We show that chloroplast trigger factor is mainly monomeric and displays only moderate stability against thermal unfolding even under mild heat-stress conditions. The global shape and conformation of these proteins were determined in solution by small-angle X-ray scattering and subsequent ab initio modelling. As observed for bacteria, plastidic trigger factors have a dragon-like structure, albeit with slightly altered domain arrangement and flexibility. This structural conservation despite low amino acid sequence homology illustrates a remarkable evolutionary robustness of chaperone conformations across various kingdoms of life.
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Affiliation(s)
- Fabian Ries
- Molecular Genetics of Eukaryotes, University of Kaiserslautern, Erwin-Schrödinger-Str. 70, 67663, Kaiserslautern, Germany
| | - Yvonne Carius
- Department of Structural Biology, Saarland University, Center of Human and Molecular Biology (ZHMB), Faculty of Medicine Building 60, 66421, Homburg, Germany
| | - Marina Rohr
- Molecular Genetics of Eukaryotes, University of Kaiserslautern, Erwin-Schrödinger-Str. 70, 67663, Kaiserslautern, Germany
| | - Karin Gries
- Molecular Genetics of Eukaryotes, University of Kaiserslautern, Erwin-Schrödinger-Str. 70, 67663, Kaiserslautern, Germany
| | - Sandro Keller
- Molecular Biophysics, University of Kaiserslautern, Erwin-Schrödinger-Str. 13, 67663, Kaiserslautern, Germany
| | - C Roy D Lancaster
- Department of Structural Biology, Saarland University, Center of Human and Molecular Biology (ZHMB), Faculty of Medicine Building 60, 66421, Homburg, Germany.
| | - Felix Willmund
- Molecular Genetics of Eukaryotes, University of Kaiserslautern, Erwin-Schrödinger-Str. 70, 67663, Kaiserslautern, Germany.
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26
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Bhor SA, Tateda C, Mochizuki T, Sekine KT, Yaeno T, Yamaoka N, Nishiguchi M, Kobayashi K. Inducible transgenic tobacco system to study the mechanisms underlying chlorosis mediated by the silencing of chloroplast heat shock protein 90. Virusdisease 2017; 28:81-92. [PMID: 28466059 PMCID: PMC5377861 DOI: 10.1007/s13337-017-0361-0] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2016] [Accepted: 01/12/2017] [Indexed: 12/11/2022] Open
Abstract
Chlorosis is one of the most common symptoms of plant diseases, including those caused by viruses and viroids. Recently, a study has shown that Peach latent mosaic viroid (PLMVd) exploits host RNA silencing machinery to modulate the virus disease symptoms through the silencing of chloroplast-targeted heat shock protein 90 (Hsp90C). To understand the molecular mechanisms of chlorosis in this viroid disease, we established an experimental system suitable for studying the mechanism underlying the chlorosis induced by the RNA silencing of Hsp90C in transgenic tobacco. Hairpin RNA of the Hsp90C-specific region was expressed under the control of a dexamethasone-inducible promoter, resulted in the silencing of Hsp90C gene in 2 days and the chlorosis along with growth suppression phenotypes. Time course study suggests that a sign of chlorosis can be monitored as early as 2 days, suggesting that this experimental model is suitable for studying the molecular events taken place before and after the onset of chlorosis. During the early phase of chlorosis development, the chloroplast- and photosynthesis-related genes were downregulated. It should be noted that some pathogenesis related genes were upregulated during the early phase of chlorosis in spite of the absence of any pathogen-derived molecules in this system.
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Affiliation(s)
- Sachin Ashok Bhor
- The United Graduate School of Agricultural Sciences, Ehime University, Matsuyama, Ehime 790-8566 Japan
| | - Chika Tateda
- Iwate Biotechnology Research Center, Kitakami, Iwate 024-0003 Japan
| | - Tomofumi Mochizuki
- Graduate School of Life and Environmental Sciences, Osaka Prefecture University, Sakai, Osaka 599-8531 Japan
| | - Ken-Taro Sekine
- Iwate Biotechnology Research Center, Kitakami, Iwate 024-0003 Japan
- Faculty of Agriculture, University of the Ryukyus, Nakagami, Okinawa 903-0213 Japan
| | - Takashi Yaeno
- The United Graduate School of Agricultural Sciences, Ehime University, Matsuyama, Ehime 790-8566 Japan
- Faculty of Agriculture, Ehime University, 3-5-7 Tarumi, Matsuyama, Ehime 790-8566 Japan
- Research Unit for Citromics, Ehime University, Matsuyama, Ehime 790-8566 Japan
| | - Naoto Yamaoka
- The United Graduate School of Agricultural Sciences, Ehime University, Matsuyama, Ehime 790-8566 Japan
- Faculty of Agriculture, Ehime University, 3-5-7 Tarumi, Matsuyama, Ehime 790-8566 Japan
| | - Masamichi Nishiguchi
- Faculty of Agriculture, Ehime University, 3-5-7 Tarumi, Matsuyama, Ehime 790-8566 Japan
| | - Kappei Kobayashi
- The United Graduate School of Agricultural Sciences, Ehime University, Matsuyama, Ehime 790-8566 Japan
- Faculty of Agriculture, Ehime University, 3-5-7 Tarumi, Matsuyama, Ehime 790-8566 Japan
- Research Unit for Citromics, Ehime University, Matsuyama, Ehime 790-8566 Japan
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27
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Maikova A, Zalutskaya Z, Lapina T, Ermilova E. The HSP70 chaperone machines of Chlamydomonas are induced by cold stress. JOURNAL OF PLANT PHYSIOLOGY 2016; 204:85-91. [PMID: 27543887 DOI: 10.1016/j.jplph.2016.07.012] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/28/2016] [Revised: 07/18/2016] [Accepted: 07/19/2016] [Indexed: 05/16/2023]
Abstract
The responses of Chlamydomonas reinhardtii cells to low temperatures have not been extensively studied compared with other stresses. Like other organisms, this green alga has heat shock protein 70s (HSP70s) that are located in chloroplast, mitochondrion and cytosol. To test whether temperature downshifts affected HSP70s synthesis, we used real-time PCR and protein gel blot analysis. C. reinhardtii cells exposed to cold stress show increased HSP70s mRNA levels. Genes encoding other components of HSP70 chaperone machines (e.g. CGE1, CDJ1, HSP90C and HSP90A) are also up-regulated in response to decreased temperature. We demonstrated that the accumulation of all analyzed mRNA occur more slowly and with reduced amplitude in cells exposed to cold than in cells treated with heat. Furthermore, C. reinhardtii cells display the splicing of the CGE1 transcript that was dependent on low temperature. Finally, the transcription regulator of C. reinhardtii HSF1 is also cold-responsive, suggesting its role in the transcriptional regulation of HSP genes at low temperature.
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Affiliation(s)
- Anna Maikova
- Biological Faculty, Saint-Petersburg State University, Universitetskaya nab. 7/9, Saint-Petersburg 199034, Russia
| | - Zhanneta Zalutskaya
- Biological Faculty, Saint-Petersburg State University, Universitetskaya nab. 7/9, Saint-Petersburg 199034, Russia
| | - Tatiana Lapina
- Biological Faculty, Saint-Petersburg State University, Universitetskaya nab. 7/9, Saint-Petersburg 199034, Russia
| | - Elena Ermilova
- Biological Faculty, Saint-Petersburg State University, Universitetskaya nab. 7/9, Saint-Petersburg 199034, Russia.
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28
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Trösch R, Mühlhaus T, Schroda M, Willmund F. ATP-dependent molecular chaperones in plastids--More complex than expected. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2015; 1847:872-88. [PMID: 25596449 DOI: 10.1016/j.bbabio.2015.01.002] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 10/31/2014] [Revised: 01/03/2015] [Accepted: 01/08/2015] [Indexed: 11/27/2022]
Abstract
Plastids are a class of essential plant cell organelles comprising photosynthetic chloroplasts of green tissues, starch-storing amyloplasts of roots and tubers or the colorful pigment-storing chromoplasts of petals and fruits. They express a few genes encoded on their organellar genome, called plastome, but import most of their proteins from the cytosol. The import into plastids, the folding of freshly-translated or imported proteins, the degradation or renaturation of denatured and entangled proteins, and the quality-control of newly folded proteins all require the action of molecular chaperones. Members of all four major families of ATP-dependent molecular chaperones (chaperonin/Cpn60, Hsp70, Hsp90 and Hsp100 families) have been identified in plastids from unicellular algae to higher plants. This review aims not only at giving an overview of the most current insights into the general and conserved functions of these plastid chaperones, but also into their specific plastid functions. Given that chloroplasts harbor an extreme environment that cycles between reduced and oxidized states, that has to deal with reactive oxygen species and is highly reactive to environmental and developmental signals, it can be presumed that plastid chaperones have evolved a plethora of specific functions some of which are just about to be discovered. Here, the most urgent questions that remain unsolved are discussed, and guidance for future research on plastid chaperones is given. This article is part of a Special Issue entitled: Chloroplast Biogenesis.
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Affiliation(s)
- Raphael Trösch
- TU Kaiserslautern, Molecular Biotechnology & Systems Biology, Paul-Ehrlich-Straße 23, 67663 Kaiserslautern, Germany; HU Berlin, Institute of Biology, Chausseestraße 117, 10115 Berlin, Germany; TU Kaiserslautern, Molecular Genetics of Eukaryotes, Paul-Ehrlich-Straße 23, 67663 Kaiserslautern, Germany.
| | - Timo Mühlhaus
- TU Kaiserslautern, Molecular Biotechnology & Systems Biology, Paul-Ehrlich-Straße 23, 67663 Kaiserslautern, Germany.
| | - Michael Schroda
- TU Kaiserslautern, Molecular Biotechnology & Systems Biology, Paul-Ehrlich-Straße 23, 67663 Kaiserslautern, Germany.
| | - Felix Willmund
- TU Kaiserslautern, Molecular Genetics of Eukaryotes, Paul-Ehrlich-Straße 23, 67663 Kaiserslautern, Germany.
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29
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Doron L, Segal N, Gibori H, Shapira M. The BSD2 ortholog in Chlamydomonas reinhardtii is a polysome-associated chaperone that co-migrates on sucrose gradients with the rbcL transcript encoding the Rubisco large subunit. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2014; 80:345-55. [PMID: 25124725 DOI: 10.1111/tpj.12638] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/10/2013] [Revised: 07/13/2014] [Accepted: 08/04/2014] [Indexed: 05/13/2023]
Abstract
The expression of the CO2 -fixation enzyme ribulose-bisphosphate carboxylase/oxygenase (Rubisco), which is affected by light, involves the cysteine-rich protein bundle-sheath defective-2 (BSD2) that was originally identified in maize bundle-sheath cells. We identified the BSD2 ortholog in Chlamydomonas reinhardtii as a small protein (17 kDa) localized to the chloroplast. The algal BSD2-ortholog contains four CXXCXGXG DnaJ-like elements, but lacks the other conserved domains of DnaJ. BSD2 co-migrated with the rbcL transcript on heavy polysomes, and both BSD2 and rbcL mRNA shifted to the lighter fractions under oxidizing conditions that repress the translation of the Rubisco large subunit (RbcL). This profile of co-migration supports the possibility that BSD2 is required for the de novo synthesis of RbcL. Furthermore, BSD2 co-migrated with the rbcL transcript in a C. reinhardtii premature-termination mutant that encodes the first 60 amino acids of RbcL. In both strains, BSD2 shared its migration profile with the rbcL transcript but not with psbA mRNA. The chaperone activity of BSD2 was exemplified by its ability to prevent the aggregation of both citrate synthase (CS) and RbcL in vitro following their chemical denaturation. This activity did not depend on the presence of the thiol groups on BSD2. In contrast, the activity of BSD2 in preventing the precipitation of reduced β-chains in vitro in the insulin turbidity assay was thiol-dependent. We conclude that BSD2 combines a chaperone 'holdase' function with the ability to interact with free thiols, with both activities being required to protect newly synthesized RbcL chains.
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Affiliation(s)
- Lior Doron
- Department of Life Sciences, Ben-Gurion University of the Negev, POB 653, Beer Sheva, 84105, Israel
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30
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Oh SE, Yeung C, Babaei-Rad R, Zhao R. Cosuppression of the chloroplast localized molecular chaperone HSP90.5 impairs plant development and chloroplast biogenesis in Arabidopsis. BMC Res Notes 2014; 7:643. [PMID: 25216779 PMCID: PMC4168064 DOI: 10.1186/1756-0500-7-643] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2014] [Accepted: 09/11/2014] [Indexed: 01/08/2023] Open
Abstract
BACKGROUND HSP90.5 is a chloroplast localized HSP90 family molecular chaperone in Arabidopsis, and it has been implicated in plant abiotic stress resistance, photomorphogenesis and nuclear-encoded protein import into the chloroplast. However, how these processes are controlled by HSP90 is not well understood. To understand the role of HSP90.5 in chloroplast function and biogenesis, in this study, we generated transgenic Arabidopsis plants that overexpress a C-terminally FLAG-tagged HSP90.5. By characterizing three HSP90.5 cosuppression lines, we demonstrated the essential role of HSP90.5 in plant growth and chloroplast biogenesis. RESULTS Immunoblotting and quantitative PCR analyses revealed three independent HSP90.5 cosuppressing transgenic lines. All three cosuppression lines displayed a certain degree of variegated phenotype in photosynthetic tissues, and the cosuppression did not affect the expression of cytosolic HSP90 isoforms. HSP90.5 cosuppression was shown to be developmentally regulated and occurred mostly at late developmental stage in adult leaves and inflorescence tissues. HSP90.5 cosuppression also caused significantly reduced rosette leaf growth, transient starch storage, but did not affect rosette leaf initiation or inflorescence production, although the fertility was reduced. Isolation of chloroplasts and size exclusion chromatography analysis indicated that the FLAG at the HSP90.5 C-terminus does not affect its proper chloroplast localization and dimerization. Finally, transmission electron microscopy indicated that chloroplast development in HSP90.5 cosuppression leaves was significantly impaired and the integrity of chloroplast is highly correlated to the expression level of HSP90.5. CONCLUSION We thoroughly characterized three HSP90.5 cosuppression lines, and demonstrated that properly controlled expression of HSP90.5 is required for plant growth and development in many tissues, and especially essential for chloroplast thylakoid formation. Since the homozygote of HSP90.5 knockout mutant is embryonically lethal, this study provides transgenic lines that mimic the conditional knockout line or siRNA line of the essential HSP90.5 gene in Arabidopsis.
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Affiliation(s)
- Saehong E Oh
- Department of Biological Sciences, University of Toronto, 1265 Military Trail, Scarborough, Ontario M1C 1A4 Canada
| | - Christine Yeung
- Department of Biological Sciences, University of Toronto, 1265 Military Trail, Scarborough, Ontario M1C 1A4 Canada
| | - Rebecca Babaei-Rad
- Department of Biological Sciences, University of Toronto, 1265 Military Trail, Scarborough, Ontario M1C 1A4 Canada
| | - Rongmin Zhao
- Department of Biological Sciences, University of Toronto, 1265 Military Trail, Scarborough, Ontario M1C 1A4 Canada
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31
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Paila YD, Richardson LGL, Schnell DJ. New insights into the mechanism of chloroplast protein import and its integration with protein quality control, organelle biogenesis and development. J Mol Biol 2014; 427:1038-1060. [PMID: 25174336 DOI: 10.1016/j.jmb.2014.08.016] [Citation(s) in RCA: 92] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2014] [Revised: 08/20/2014] [Accepted: 08/23/2014] [Indexed: 01/04/2023]
Abstract
The translocons at the outer (TOC) and the inner (TIC) envelope membranes of chloroplasts mediate the targeting and import of several thousand nucleus-encoded preproteins that are required for organelle biogenesis and homeostasis. The cytosolic events in preprotein targeting remain largely unknown, although cytoplasmic chaperones have been proposed to facilitate delivery to the TOC complex. Preprotein recognition is mediated by the TOC GTPase receptors Toc159 and Toc34. The receptors constitute a GTP-regulated switch, which initiates membrane translocation via Toc75, a member of the Omp85 (outer membrane protein 85)/TpsB (two-partner secretion system B) family of bacterial, plastid and mitochondrial β-barrel outer membrane proteins. The TOC receptor systems have diversified to recognize distinct sets of preproteins, thereby maximizing the efficiency of targeting in response to changes in gene expression during developmental and physiological events that impact organelle function. The TOC complex interacts with the TIC translocon to allow simultaneous translocation of preproteins across the envelope. Both the two inner membrane complexes, the Tic110 and 1 MDa complexes, have been implicated as constituents of the TIC translocon, and it remains to be determined how they interact to form the TIC channel and assemble the import-associated chaperone network in the stroma that drives import across the envelope membranes. This review will focus on recent developments in our understanding of the mechanisms and diversity of the TOC-TIC systems. Our goal is to incorporate these recent studies with previous work and present updated or revised models for the function of TOC-TIC in protein import.
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Affiliation(s)
- Yamuna D Paila
- Department of Biochemistry and Molecular Biology, Life Sciences Laboratories Room N431, 240 Thatcher Rd, University of Massachusetts, Amherst MA 01003-9364, USA
| | - Lynn G L Richardson
- Department of Biochemistry and Molecular Biology, Life Sciences Laboratories Room N431, 240 Thatcher Rd, University of Massachusetts, Amherst MA 01003-9364, USA
| | - Danny J Schnell
- Department of Biochemistry and Molecular Biology, Life Sciences Laboratories Room N431, 240 Thatcher Rd, University of Massachusetts, Amherst MA 01003-9364, USA
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32
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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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33
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Cloning and expression of a cytosolic HSP90 gene in Chlorella vulgaris. BIOMED RESEARCH INTERNATIONAL 2014; 2014:487050. [PMID: 24738061 PMCID: PMC3971552 DOI: 10.1155/2014/487050] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/04/2013] [Accepted: 01/16/2014] [Indexed: 12/31/2022]
Abstract
Heat shock protein 90 (HSP90), a highly conserved molecular chaperone, plays essential roles in folding, keeping structural integrity, and regulating the subset of cytosolic proteins. We cloned the cDNA of Chlorella vulgaris HSP90 (named CvHSP90) by combining homology cloning with rapid amplification of cDNA ends (RACE). Sequence analysis indicated that CvHSP90 is a cytosolic member of the HSP90 family. Quantitative RT-PCR was applied to determine the expression level of messenger RNA (mRNA) in CvHSP90 under different stress conditions. C. vulgaris was kept in different temperatures (5–45°C) for 1 h. The mRNA expression level of CvHSP90 increased with temperature from 5 to 10°C, went further from 35 to 40°C, and reached the maximum at 40°C. On the other hand, for C. vulgaris kept at 35°C for different durations, the mRNA expression level of CvHSP90 increased gradually and reached the peak at 7 h and then declined progressively. In addition, the expression level of CvHSP90 at 40 or 45 in salinity (‰) was almost fourfold of that at 25 in salinity (‰) for 2 h. Therefore, CvHSP90 may be a potential biomarker to monitor environment changes.
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34
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Feng J, Fan P, Jiang P, Lv S, Chen X, Li Y. Chloroplast-targeted Hsp90 plays essential roles in plastid development and embryogenesis in Arabidopsis possibly linking with VIPP1. PHYSIOLOGIA PLANTARUM 2014; 150:292-307. [PMID: 23875936 DOI: 10.1111/ppl.12083] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/19/2013] [Revised: 05/14/2013] [Accepted: 06/15/2013] [Indexed: 05/20/2023]
Abstract
The Arabidopsis genome contains seven members of Hsp90. Mutations in plastid AtHsp90.5 were reported to cause defects in chloroplast development and embryogenesis. However, the exact function of plastid AtHsp90.5 has not yet been defined. In this study, albino seedlings were found among AtHsp90.5 transformed Arabidopsis, which were revealed to be AtHsp90.5 co-suppressed plants. The accumulation of photosynthetic super-complexes in the albinos was decreased, and expression of genes involved in photosynthesis was significantly down-regulated. AtHsp90.5 T-DNA insertion mutants were embryo-lethal with embryo arrested at the heart stage. Further investigation showed AtHsp90.5 expression was up-regulated in the siliques at 4 days post anthesis (DPA). Confocal microscopy proved AtHsp90.5 was located in the chloroplasts. Plastid development in the AtHsp90.5 mutants and co-suppressed plants was seriously impaired, and few thylakoid membranes were observed, indicating the involvement of AtHsp90.5 in chloroplast biogenesis. AtHsp90.5 was found to interact with vesicle-inducing protein in plastids 1 (VIPP1) by bimolecular fluorescence complementation system. The ratio between VIPP1 oligomers and monomers in AtHsp90.5 co-suppressed plants drastically shifted toward the oligomeric state. Our study confirmed that AtHsp90.5 is vital for chloroplast biogenesis and embryogenesis. Further evidence also suggested that AtHsp90.5 may help in the disassembly of VIPP1 for thylakoid membrane formation and/or maintenance.
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Affiliation(s)
- Juanjuan Feng
- Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, P.R. China
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Abstract
Hsp70 chaperones are involved in multiple biological processes and are recruited to specific processes by designated J domain-containing cochaperones, or J proteins. To understand the evolution and functions of chloroplast Hsp70s and J proteins, we identified the Arabidopsis chloroplast J protein constituency using a combination of genomic and proteomic database searches and individual protein import assays. We show that Arabidopsis chloroplasts have at least 19 J proteins, the highest number of confirmed J proteins for any organelle. These 19 J proteins are classified into 11 clades, for which cyanobacteria and glaucophytes only have homologs for one clade, green algae have an additional three clades, and all the other 7 clades are specific to land plants. Each clade also possesses a clade-specific novel motif that is likely used to interact with different client proteins. Gene expression analyses indicate that most land plant-specific J proteins show highly variable expression in different tissues and are down regulated by low temperatures. These results show that duplication of chloroplast Hsp70 in land plants is accompanied by more than doubling of the number of its J protein cochaperones through adding new J proteins with novel motifs, not through duplications within existing families. These new J proteins likely recruit chloroplast Hsp70 to perform tissue specific functions related to biosynthesis rather than to stress resistance.
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Inoue H, Li M, Schnell DJ. An essential role for chloroplast heat shock protein 90 (Hsp90C) in protein import into chloroplasts. Proc Natl Acad Sci U S A 2013; 110:3173-8. [PMID: 23382192 PMCID: PMC3581895 DOI: 10.1073/pnas.1219229110] [Citation(s) in RCA: 80] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Chloroplast heat shock protein 90 (Hsp90C) represents a highly conserved subfamily of the Hsp90 family of molecular chaperones whose function has not been defined. We identified Hsp90C as a component that interacts with import intermediates of nuclear-encoded preproteins during posttranslational import into isolated chloroplasts. Hsp90C was specifically coprecipitated with a complex of protein import components, including Tic110, Tic40, Toc75, Tic22, and the stromal chaperones, Hsp93 and Hsp70. Radicicol, an inhibitor of Hsp90 ATPase activity, reversibly inhibited the import of a variety of preproteins during translocation across the inner envelope membrane, indicating that Hsp90C functions in membrane translocation into the organelle. Hsp90C is encoded by a single gene in Arabidopsis thaliana, and insertion mutations in the Hsp90C gene are embryo lethal, indicating an essential function for the chaperone in plant viability. On the basis of these results, we propose that Hsp90C functions within a chaperone complex in the chloroplast stroma to facilitate membrane translocation during protein import into the organelle.
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Affiliation(s)
- Hitoshi Inoue
- Department of Biochemistry and Molecular Biology, University of Massachusetts, Amherst, MA 01003
| | | | - Danny J. Schnell
- Department of Biochemistry and Molecular Biology, University of Massachusetts, Amherst, MA 01003
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De Marchis F, Pompa A, Bellucci M. Plastid proteostasis and heterologous protein accumulation in transplastomic plants. PLANT PHYSIOLOGY 2012; 160:571-81. [PMID: 22872774 PMCID: PMC3461539 DOI: 10.1104/pp.112.203778] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
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Navarro B, Gisel A, Rodio ME, Delgado S, Flores R, Di Serio F. Small RNAs containing the pathogenic determinant of a chloroplast-replicating viroid guide the degradation of a host mRNA as predicted by RNA silencing. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2012; 70:991-1003. [PMID: 22332758 DOI: 10.1111/j.1365-313x.2012.04940.x] [Citation(s) in RCA: 140] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
How viroids, tiny non-protein-coding RNAs (~250-400 nt), incite disease is unclear. One hypothesis is that viroid-derived small RNAs (vd-sRNAs; 21-24 nt) resulting from the host defensive response, via RNA silencing, may target for cleavage cell mRNAs and trigger a signal cascade, eventually leading to symptoms. Peach latent mosaic viroid (PLMVd), a chloroplast-replicating viroid, is particularly appropriate to tackle this question because it induces an albinism (peach calico, PC) strictly associated with variants containing a specific 12-14-nt hairpin insertion. By dissecting albino and green leaf sectors of Prunus persica (peach) seedlings inoculated with PLMVd natural and artificial variants, and cloning their progeny, we have established that the hairpin insertion sequence is involved in PC. Furthermore, using deep sequencing, semi-quantitative RT-PCR and RNA ligase-mediated rapid amplification of cDNA ends (RACE), we have determined that two PLMVd-sRNAs containing the PC-associated insertion (PC-sRNA8a and PC-sRNA8b) target for cleavage the mRNA encoding the chloroplastic heat-shock protein 90 (cHSP90), thus implicating RNA silencing in the modulation of host gene expression by a viroid. Chloroplast malformations previously reported in PC-expressing tissues are consistent with the downregulation of cHSP90, which participates in chloroplast biogenesis and plastid-to-nucleus signal transduction in Arabidopsis. Besides PC-sRNA8a and PC-sRNA8b, both deriving from the less-abundant PLMVd (-) strand, we have identified other PLMVd-sRNAs potentially targeting peach mRNAs. These results also suggest that sRNAs derived from other PLMVd regions may downregulate additional peach genes, ultimately resulting in other symptoms or in a more favorable host environment for viroid infection.
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Affiliation(s)
- Beatriz Navarro
- Istituto di Virologia Vegetale-CNR, Unità Organizzativa di Bari, Via Amendola 165/A, 70126 Bari, Italy
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Navarro B, Gisel A, Rodio ME, Delgado S, Flores R, Di Serio F. Viroids: how to infect a host and cause disease without encoding proteins. Biochimie 2012; 94:1474-80. [PMID: 22738729 DOI: 10.1016/j.biochi.2012.02.020] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2011] [Accepted: 02/16/2012] [Indexed: 10/28/2022]
Abstract
Despite being composed by a single-stranded, circular, non-protein-coding RNA of just 246-401 nucleotides (nt), viroids can incite in their host plants symptoms similar to those caused by DNA and RNA viruses, which have genomes at least 20-fold bigger and encode proteins. On the other hand, certain non-protein-coding plant satellite RNAs display structural similarities with viroids but for replication and transmission they need to parasitize specific helper viruses (modifying concomitantly the symptoms they induce). While phenotypic alterations accompanying infection by viruses may partly result from expressing the proteins they code for, how the non-protein-coding viroids (and satellite RNAs) cause disease remains a conundrum. Initial ideas on viroid pathogenesis focused on a direct interaction of the genomic RNA with host proteins resulting in their malfunction. With the advent of RNA silencing, it was alternatively proposed that symptoms could be produced by viroid-derived small RNAs (vd-sRNAs) -generated by the host defensive machinery- targeting specific host mRNA or DNA sequences for post-transcriptional or transcriptional gene silencing, respectively, a hypothesis that could also explain pathogenesis of non-protein-coding satellite RNAs. Evidence sustaining this view has been circumstantial, but recent data provide support for it in two cases: i) the yellow symptoms associated with a specific satellite RNA result from a 22-nt small RNA (derived from the 24-nt fragment of the satellite genome harboring the pathogenic determinant), which is complementary to a segment of the mRNA of the chlorophyll biosynthetic gene CHLI and targets it for cleavage by the RNA silencing machinery, and ii) two 21-nt vd-sRNAS containing the pathogenic determinant of the albino phenotype induced by a chloroplast-replicating viroid target for cleavage the mRNA coding for the chloroplastic heat-shock protein 90 via RNA silencing too. This evidence, which is compelling for the satellite RNA, does not exclude alternative mechanisms.
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Affiliation(s)
- Beatriz Navarro
- Istituto di Virologia Vegetale (CNR), Unità Organizzativa di Bari, Via Amendola 165/A, 70126 Bari, Italy
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Chen KM, Piippo M, Holmström M, Nurmi M, Pakula E, Suorsa M, Aro EM. A chloroplast-targeted DnaJ protein AtJ8 is negatively regulated by light and has rapid turnover in darkness. JOURNAL OF PLANT PHYSIOLOGY 2011; 168:1780-3. [PMID: 21592617 DOI: 10.1016/j.jplph.2011.04.001] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/15/2011] [Revised: 04/12/2011] [Accepted: 04/12/2011] [Indexed: 05/20/2023]
Abstract
The DnaJ proteins (also called as J proteins, J domain proteins or HSP40 proteins) function as molecular co-chaperones for the HSP70 proteins. We assessed the expression of the small chloroplast-targeted DnaJ protein, the AtJ8 protein, by subjecting the wild type Arabidopsis plants to different illumination conditions. It is shown that the expression of the transcripts and proteins of the ATJ8 gene is primarily regulated at the level of transcription. When plants were incubated under high light for 3h, both the transcripts and proteins were completely abolished. Upon transfer of plants to darkness, the transcripts started rapidly accumulating, and subsequently, the AtJ8 protein became visible after 2h in darkness. Conversely, incubation of plants in darkness or under low light intensities induced expression of the ATJ8 transcripts and proteins. Feeding plants with sugars clearly decreased the transcript and protein levels, and incubation with cycloheximide revealed a rapid turnover for AtJ8 in darkness. Moreover, the AtJ8 protein was found to be nearly missing from the var1 mutant, which lacks the FTSH5 protease. It is concluded that AtJ8 is expressed mainly in darkness, is prone to a rapid turnover but is partially stabilized by the FTSH proteases.
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Affiliation(s)
- Kun-Ming Chen
- College of Life Sciences, Northwest A&F University, Yangling 712100, Shaanxi, China
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Abstract
Mutations at the APM1 and APM2 loci in the green alga Chlamydomonas reinhardtii confer resistance to phosphorothioamidate and dinitroaniline herbicides. Genetic interactions between apm1 and apm2 mutations suggest an interaction between the gene products. We identified the APM1 and APM2 genes using a map-based cloning strategy. Genomic DNA fragments containing only the DNJ1 gene encoding a type I Hsp40 protein rescue apm1 mutant phenotypes, conferring sensitivity to the herbicides and rescuing a temperature-sensitive growth defect. Lesions at five apm1 alleles include missense mutations and nucleotide insertions and deletions that result in altered proteins or very low levels of gene expression. The HSP70A gene, encoding a cytosolic Hsp70 protein known to interact with Hsp40 proteins, maps near the APM2 locus. Missense mutations found in three apm2 alleles predict altered Hsp70 proteins. Genomic fragments containing the HSP70A gene rescue apm2 mutant phenotypes. The results suggest that a client of the Hsp70-Hsp40 chaperone complex may function to increase microtubule dynamics in Chlamydomonas cells. Failure of the chaperone system to recognize or fold the client protein(s) results in increased microtubule stability and resistance to the microtubule-destabilizing effect of the herbicides. The lack of redundancy of genes encoding cytosolic Hsp70 and Hsp40 type I proteins in Chlamydomonas makes it a uniquely valuable system for genetic analysis of the function of the Hsp70 chaperone complex.
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De Marchis F, Pompa A, Mannucci R, Morosinotto T, Bellucci M. A plant secretory signal peptide targets plastome-encoded recombinant proteins to the thylakoid membrane. PLANT MOLECULAR BIOLOGY 2011; 76:427-41. [PMID: 20714919 DOI: 10.1007/s11103-010-9676-6] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/29/2010] [Accepted: 07/21/2010] [Indexed: 05/29/2023]
Abstract
Plastids are considered promising bioreactors for the production of recombinant proteins, but the knowledge of the mechanisms regulating foreign protein folding, targeting, and accumulation in these organelles is still incomplete. Here we demonstrate that a plant secretory signal peptide is able to target a plastome-encoded recombinant protein to the thylakoid membrane. The fusion protein zeolin with its native signal peptide expressed by tobacco (Nicotiana tabacum) transplastomic plants was directed into the chloroplast thylakoid membranes, whereas the zeolin mutant devoid of the signal peptide, Δzeolin, is instead accumulated in the stroma. We also show that zeolin folds in the thylakoid membrane where it accumulates as trimers able to form disulphide bonds. Disulphide bonds contribute to protein accumulation since zeolin shows a higher accumulation level with respect to stromal Δzeolin, whose folding is hampered as the protein accumulates at low amounts in a monomeric form and it is not oxidized. Thus, post-transcriptional processes seem to regulate the stability and accumulation of plastid-synthesized zeolin. The most plausible zeolin targeting mechanism to thylakoid is discussed herein.
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Affiliation(s)
- Francesca De Marchis
- Istituto di Genetica Vegetale, Consiglio Nazionale delle Ricerche (CNR), via della Madonna Alta 130, 06128 Perugia, Italy
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Remmerie N, De Vijlder T, Laukens K, Dang TH, Lemière F, Mertens I, Valkenborg D, Blust R, Witters E. Next generation functional proteomics in non-model plants: A survey on techniques and applications for the analysis of protein complexes and post-translational modifications. PHYTOCHEMISTRY 2011; 72:1192-218. [PMID: 21345472 DOI: 10.1016/j.phytochem.2011.01.003] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/06/2010] [Revised: 11/21/2010] [Accepted: 01/03/2011] [Indexed: 05/11/2023]
Abstract
The congruent development of computational technology, bioinformatics and analytical instrumentation makes proteomics ready for the next leap. Present-day state of the art proteomics grew from a descriptive method towards a full stake holder in systems biology. High throughput and genome wide studies are now made at the functional level. These include quantitative aspects, functional aspects with respect to protein interactions as well as post translational modifications and advanced computational methods that aid in predicting protein function and mapping these functionalities across the species border. In this review an overview is given of the current status of these aspects in plant studies with special attention to non-genomic model plants.
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Affiliation(s)
- Noor Remmerie
- Center for Proteomics, University of Antwerp, Groenenborgerlaan 171, B-2020 Antwerp, Belgium
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Alkayal F, Albion RL, Tillett RL, Hathwaik LT, Lemos MS, Cushman JC. Expressed sequence tag (EST) profiling in hyper saline shocked Dunaliella salina reveals high expression of protein synthetic apparatus components. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2010; 179:437-49. [PMID: 21802602 DOI: 10.1016/j.plantsci.2010.07.001] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/19/2009] [Revised: 06/28/2010] [Accepted: 07/01/2010] [Indexed: 05/10/2023]
Abstract
The unicellular, halotolerant, green alga, Dunaliella salina (Chlorophyceae) has the unique ability to adapt and grow in a wide range of salt conditions from about 0.05 to 5.5M. To better understand the molecular basis of its salinity tolerance, a complementary DNA (cDNA) library was constructed from D. salina cells adapted to 2.5M NaCl, salt-shocked at 3.4M NaCl for 5h, and used to generate an expressed sequence tag (EST) database. ESTs were obtained for 2831 clones representing 1401 unique transcripts. Putative functions were assigned to 1901 (67.2%) ESTs after comparison with protein databases. An additional 154 (5.4%) ESTs had significant similarity to known sequences whose functions are unclear and 776 (27.4%) had no similarity to known sequences. For those D. salina ESTs for which functional assignments could be made, the largest functional categories included protein synthesis (35.7%), energy (photosynthesis) (21.4%), primary metabolism (13.8%) and protein fate (6.8%). Within the protein synthesis category, the vast majority of ESTs (80.3%) encoded ribosomal proteins representing about 95% of the approximately 82 subunits of the cytosolic ribosome indicating that D. salina invests substantial resources in the production and maintenance of protein synthesis. The increased mRNA expression upon salinity shock was verified for a small set of selected genes by real-time, quantitative reverse-transcription-polymerase chain reaction (qRT-PCR). This EST collection also provided important new insights into the genetic underpinnings for the biosynthesis and utilization of glycerol and other osmoprotectants, the carotenoid biosynthetic pathway, reactive oxygen-scavenging enzymes, and molecular chaperones (heat shock proteins) not described previously for D. salina. EST discovery also revealed the existence of RNA interference and signaling pathways associated with osmotic stress adaptation. The unknown ESTs described here provide a rich resource for the identification of novel genes associated with the mechanistic basis of salinity stress tolerance and other stress-adaptive traits.
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Affiliation(s)
- Fadi Alkayal
- Dasman Center for Research and Treatment of Diabetes, P.O Box 1180, Dasman, Kuwait
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Chloroplast DnaJ-like proteins 3 and 4 (CDJ3/4) from Chlamydomonas reinhardtii contain redox-active Fe–S clusters and interact with stromal HSP70B. Biochem J 2010; 427:205-15. [DOI: 10.1042/bj20091412] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
In the present study we report on the identification and characterization of three novel chloroplast-targeted DnaJ-like proteins CDJ3–5, which in addition to their J-domains contain bacterial-type ferredoxin domains. In sequence databases we could identify homologues of CDJ3–5 in green algae, moss and higher plants, but not in cyanobacteria. Phylogenetic analyses allowed us to distinguish two clades containing CDJ3/4 and CDJ5 that must have diverged early in the ancestor of the ‘green lineage’ and have further diversified later on. Molecular and biochemical analysis of CDJ3 and CDJ4 from Chlamydomonas reinhardtii revealed that both proteins are weakly expressed and appear to be localized to the stroma and to thylakoid membranes respectively. The low transcript levels of the CDJ3 and CDJ4 genes declined even further in the initial phase of heat shock, but CDJ3 transcript levels strongly increased after a dark-to-light shift. Accordingly, the Arabidopsis orthologue of CDJ5 was also found to be light-inducible and to be under strong circadian control. CDJ3 and CDJ4 proteins could both be expressed in Escherichia coli and had redox-active Fe–S clusters. In vitro cross-linking studies demonstrated that CDJ3 and CDJ4 interact with chloroplast ATP-bound HSP70B (heat-shock protein 70B), presumably as dimers, and immunoprecipitation studies showed that CDJ3/4 were also in a complex with HSP70B in Chlamydomonas cell extracts. Finally, CDJ3 was found in complexes with apparent molecular masses of approx. 550–2800 kDa, which appeared to contain RNA. We speculate that the CDJ3–5 proteins might represent redox switches that act by recruiting HSP70B for the reorganization of regulatory protein complexes.
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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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Heide H, Nordhues A, Drepper F, Nick S, Schulz-Raffelt M, Haehnel W, Schroda M. Application of quantitative immunoprecipitation combined with knockdown and cross-linking to Chlamydomonas
reveals the presence of vesicle-inducing protein in plastids 1 in a common complex with chloroplast HSP90C. Proteomics 2009; 9:3079-89. [DOI: 10.1002/pmic.200800872] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
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Schroda M, Mühlhaus T. A 'foldosome' in the chloroplast? PLANT SIGNALING & BEHAVIOR 2009; 4:301-3. [PMID: 19794845 PMCID: PMC2664489 DOI: 10.4161/psb.4.4.7758] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/04/2009] [Accepted: 01/05/2009] [Indexed: 05/20/2023]
Abstract
The proper functioning of many cytosolic proteins involved in signal transduction depends on protein folding steps carried out cooperatively by a multichaperone complex containing the Hsp90 and Hsp70 machineries. We have recently found that also in the chloroplast the Hsp90 and Hsp70 machineries form a multichaperone complex, although chloroplast Hsp90 and Hsp70 are from eukaryotic and prokaryotic origin, respectively. In earlier work by others it was shown that plants expressing a mutated form of a chloroplast-targeted Hsp90 were impaired in the light induction of several nuclear genes. These data suggest that, like in the cytosol, the folding of chloroplast proteins involved in chloroplast-to-nucleus signalling might depend on the cooperative action of the chloroplast Hsp70–Hsp90 machineries.
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Affiliation(s)
- Michael Schroda
- Max Planck Institute of Molecular Plant Physiology, Potsdam-Golm, Germany.
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