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Yang Y, Zhang G, Su M, Shi Q, Chen Q. Prefoldin Subunits and Its Associate Partners: Conservations and Specificities in Plants. PLANTS (BASEL, SWITZERLAND) 2024; 13:556. [PMID: 38498526 PMCID: PMC10893143 DOI: 10.3390/plants13040556] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/30/2024] [Revised: 02/16/2024] [Accepted: 02/17/2024] [Indexed: 03/20/2024]
Abstract
Prefoldins (PFDs) are ubiquitous co-chaperone proteins that originated in archaea during evolution and are present in all eukaryotes, including yeast, mammals, and plants. Typically, prefoldin subunits form hexameric PFD complex (PFDc) that, together with class II chaperonins, mediate the folding of nascent proteins, such as actin and tubulin. In addition to functioning as a co-chaperone in cytoplasm, prefoldin subunits are also localized in the nucleus, which is essential for transcription and post-transcription regulation. However, the specific and critical roles of prefoldins in plants have not been well summarized. In this review, we present an overview of plant prefoldin and its related proteins, summarize the structure of prefoldin/prefoldin-like complex (PFD/PFDLc), and analyze the versatile landscape by prefoldin subunits, from cytoplasm to nucleus regulation. We also focus the specific role of prefoldin-mediated phytohormone response and global plant development. Finally, we overview the emerging prefoldin-like (PFDL) subunits in plants and the novel roles in related processes, and discuss the next direction in further studies.
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Affiliation(s)
- Yi Yang
- Shandong Provincial Key Laboratory of Biophysics, Institute of Biophysics, Dezhou University, Dezhou 253023, China; (G.Z.); (M.S.)
| | - Gang Zhang
- Shandong Provincial Key Laboratory of Biophysics, Institute of Biophysics, Dezhou University, Dezhou 253023, China; (G.Z.); (M.S.)
| | - Mengyu Su
- Shandong Provincial Key Laboratory of Biophysics, Institute of Biophysics, Dezhou University, Dezhou 253023, China; (G.Z.); (M.S.)
| | - Qingbiao Shi
- National Key Laboratory of Wheat Improvement, College of Life Sciences, Shandong Agricultural University, Tai’an 271018, China;
| | - Qingshuai Chen
- Shandong Provincial Key Laboratory of Biophysics, Institute of Biophysics, Dezhou University, Dezhou 253023, China; (G.Z.); (M.S.)
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2
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Zimbone S, Di Rosa MC, Chiechio S, Giuffrida ML. Exploring the Role of Hsp60 in Alzheimer's Disease and Type 2 Diabetes: Suggestion for Common Drug Targeting. Int J Mol Sci 2023; 24:12456. [PMID: 37569831 PMCID: PMC10419248 DOI: 10.3390/ijms241512456] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2023] [Revised: 08/01/2023] [Accepted: 08/02/2023] [Indexed: 08/13/2023] Open
Abstract
Heat shock protein 60 (Hsp60) is a member of the chaperonin family of heat shock proteins (HSPs), primarily found in the mitochondrial matrix. As a molecular chaperone, Hsp60 plays an essential role in mediating protein folding and assembly, and together with the co-chaperon Hsp10, it is thought to maintain protein homeostasis. Recently, it has been found to localize in non-canonical, extra-mitochondrial sites such as cell membranes or extracellular fluids, particularly in pathological conditions. Starting from its biological function, this review aims to provide a comprehensive understanding of the potential involvement of Hsp60 in Alzheimer's disease (AD) and Type II Diabetes Mellitus (T2DM), which are known to share impaired key pathways and molecular dysfunctions. Fragmentary data reported in the literature reveal interesting links between the altered expression level or localization of this chaperonin and several disease conditions. The present work offers an overview of the past and more recent knowledge about Hsp60 and its role in the most important cellular processes to shed light on neuronal Hsp60 as a potential common target for both pathologies. The absence of any effective cure for AD patients makes the identification of a new molecular target a promising path by which to move forward in the development of new drugs and/or repositioning of therapies already used for T2DM.
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Affiliation(s)
- Stefania Zimbone
- Institute of Crystallography, National Research Council (CNR-IC), 95126 Catania, Italy; (S.Z.); (M.C.D.R.)
| | - Maria Carmela Di Rosa
- Institute of Crystallography, National Research Council (CNR-IC), 95126 Catania, Italy; (S.Z.); (M.C.D.R.)
- Cogentech Società Benefit srl Actual Position, 95121 Catania, Italy
| | - Santina Chiechio
- Department of Drug and Health Sciences, University of Catania, 95125 Catania, Italy;
- Oasi Research Institute—IRCCS, 94018 Troina, Italy
| | - Maria Laura Giuffrida
- Institute of Crystallography, National Research Council (CNR-IC), 95126 Catania, Italy; (S.Z.); (M.C.D.R.)
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Lin S, Liu Z, Sun S, Xue F, Li H, Tursun A, Cao L, Zhang L, Wilson ZA, Zhang D, Liang W. Rice HEAT SHOCK PROTEIN60-3B maintains male fertility under high temperature by starch granule biogenesis. PLANT PHYSIOLOGY 2023; 192:2301-2317. [PMID: 36861636 PMCID: PMC10315285 DOI: 10.1093/plphys/kiad136] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/04/2022] [Revised: 01/18/2023] [Accepted: 01/29/2023] [Indexed: 06/18/2023]
Abstract
Heat stress has a deleterious effect on male fertility in rice (Oryza sativa), but mechanisms to protect against heat stress in rice male gametophytes are poorly understood. Here, we have isolated and characterized a heat-sensitive male-sterile rice mutant, heat shock protein60-3b (oshsp60-3b), that shows normal fertility at optimal temperatures but decreasing fertility as temperatures increase. High temperatures interfered with pollen starch granule formation and reactive oxygen species (ROS) scavenging in oshsp60-3b anthers, leading to cell death and pollen abortion. In line with the mutant phenotypes, OsHSP60-3B was rapidly upregulated in response to heat shock and its protein products were localized to the plastid. Critically, overexpression of OsHSP60-3B enhanced the heat tolerance of pollen in transgenic plants. We demonstrated that OsHSP60-3B interacted with FLOURY ENDOSPERM6(FLO6) in plastids, a key component involved in the starch granule formation in the rice pollen. Western blot results showed that FLO6 level was substantially decreased in oshsp60-3b anthers at high temperature, indicating that OsHSP60-3B is required to stabilize FLO6 when temperatures exceed optimal conditions. We suggest that in response to high temperature, OsHSP60-3B interacts with FLO6 to regulate starch granule biogenesis in rice pollen and attenuates ROS levels in anthers to ensure normal male gametophyte development in rice.
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Affiliation(s)
- Sen Lin
- Joint International Research Laboratory of Metabolic and Developmental Sciences, State Key Laboratory of Hybrid Rice, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Ze Liu
- Joint International Research Laboratory of Metabolic and Developmental Sciences, State Key Laboratory of Hybrid Rice, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Shiyu Sun
- Joint International Research Laboratory of Metabolic and Developmental Sciences, State Key Laboratory of Hybrid Rice, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Feiyang Xue
- Joint International Research Laboratory of Metabolic and Developmental Sciences, State Key Laboratory of Hybrid Rice, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Huanjun Li
- Joint International Research Laboratory of Metabolic and Developmental Sciences, State Key Laboratory of Hybrid Rice, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Askar Tursun
- Joint International Research Laboratory of Metabolic and Developmental Sciences, State Key Laboratory of Hybrid Rice, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Lichun Cao
- Joint International Research Laboratory of Metabolic and Developmental Sciences, State Key Laboratory of Hybrid Rice, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Long Zhang
- Key Laboratory of Crop Genetics and Physiology of Jiangsu Province, Jiangsu Key Laboratory of Crop Genomics and Molecular Breeding, Yangzhou University, Yangzhou 225009, China
| | - Zoe A Wilson
- Division of Plant & Crop Sciences, School of Biosciences, University of Nottingham, Sutton Bonington Campus, Loughborough, Leicestershire LE12 5RD, UK
| | - Dabing Zhang
- Joint International Research Laboratory of Metabolic and Developmental Sciences, State Key Laboratory of Hybrid Rice, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China
- School of Agriculture, Food and Wine, University of Adelaide, Waite Campus, Glen Osmond, South Australia 5064, Australia
| | - Wanqi Liang
- Joint International Research Laboratory of Metabolic and Developmental Sciences, State Key Laboratory of Hybrid Rice, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China
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Thye KL, Wan Abdullah WMAN, Ong-Abdullah J, Lamasudin DU, Wee CY, Mohd Yusoff MHY, Loh JY, Cheng WH, Lai KS. Calcium lignosulfonate modulates physiological and biochemical responses to enhance shoot multiplication in Vanilla planifolia Andrews. PHYSIOLOGY AND MOLECULAR BIOLOGY OF PLANTS : AN INTERNATIONAL JOURNAL OF FUNCTIONAL PLANT BIOLOGY 2023; 29:377-392. [PMID: 37033764 PMCID: PMC10073391 DOI: 10.1007/s12298-023-01293-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/08/2022] [Revised: 02/01/2023] [Accepted: 02/14/2023] [Indexed: 06/19/2023]
Abstract
Utilisation of calcium lignosulfonate (CaLS) in Vanilla planifolia has been reported to improve shoot multiplication. However, mechanisms responsible for such observation remain unknown. Here, we elucidated the underlying mechanisms of CaLS in promoting shoot multiplication of V. planifolia via comparative proteomics, biochemical assays, and nutrient analysis. The proteome profile of CaLS-treated plants showed enhancement of several important cellular metabolisms such as photosynthesis, protein synthesis, Krebs cycle, glycolysis, gluconeogenesis, and carbohydrate synthesis. Further biochemical analysis recorded that CaLS increased Rubisco activity, hexokinase activity, isocitrate dehydrogenase activity, total carbohydrate content, glutamate synthase activity and total protein content in plant shoot, suggesting the role of CaLS in enhancing shoot growth via upregulation of cellular metabolism. Subsequent nutrient analysis showed that CaLS treatment elevated the contents of several nutrient ions especially calcium and sodium ions. In addition, our study also revealed that CaLS successfully maintained the cellular homeostasis level through the regulation of signalling molecules such as reactive oxygen species and calcium ions. These results demonstrated that the CaLS treatment can enhance shoot multiplication in V. planifolia Andrews by stimulating nutrient uptake, inducing cell metabolism, and regulating cell homeostasis. Supplementary Information The online version contains supplementary material available at 10.1007/s12298-023-01293-w.
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Affiliation(s)
- Kah-Lok Thye
- Department of Cell and Molecular Biology, Faculty of Biotechnology and Biomolecular Sciences, Universiti Putra Malaysia, 43400 Serdang, Selangor Malaysia
| | - Wan Muhamad Asrul Nizam Wan Abdullah
- Department of Cell and Molecular Biology, Faculty of Biotechnology and Biomolecular Sciences, Universiti Putra Malaysia, 43400 Serdang, Selangor Malaysia
| | - Janna Ong-Abdullah
- Department of Cell and Molecular Biology, Faculty of Biotechnology and Biomolecular Sciences, Universiti Putra Malaysia, 43400 Serdang, Selangor Malaysia
| | - Dhilia Udie Lamasudin
- Department of Cell and Molecular Biology, Faculty of Biotechnology and Biomolecular Sciences, Universiti Putra Malaysia, 43400 Serdang, Selangor Malaysia
| | - Chien-Yeong Wee
- Biotechnology and Nanotechnology Research Centre, Malaysian Agricultural Research and Development Institute, 43400 Serdang, Selangor Malaysia
| | | | - Jiun-Yan Loh
- Centre of Research for Advanced Aquaculture, UCSI University, No. 1, Jalan Menara Gading, UCSI Heights, 56000 Cheras, Kuala Lumpur Malaysia
| | - Wan-Hee Cheng
- Faculty of Health and Life Sciences, INTI International University, Persiaran Perdana BBN, Putra Nilai, 71800 Nilai, Negeri Sembilan Malaysia
| | - Kok-Song Lai
- Health Sciences Division, Abu Dhabi Women’s College, Higher Colleges of Technology, 41012 Abu Dhabi, United Arab Emirates
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Boshoff A. Chaperonin: Co-chaperonin Interactions. Subcell Biochem 2023; 101:213-246. [PMID: 36520309 DOI: 10.1007/978-3-031-14740-1_8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
Co-chaperonins function together with chaperonins to mediate ATP-dependent protein folding in a variety of cellular compartments. Chaperonins are evolutionarily conserved and form two distinct classes, namely, group I and group II chaperonins. GroEL and its co-chaperonin GroES form part of group I and are the archetypal members of this family of protein folding machines. The unique mechanism used by GroEL and GroES to drive protein folding is embedded in the complex architecture of double-ringed complexes, forming two central chambers that undergo conformational rearrangements that enable protein folding to occur. GroES forms a lid over the chamber and in doing so dislodges bound substrate into the chamber, thereby allowing non-native proteins to fold in isolation. GroES also modulates allosteric transitions of GroEL. Group II chaperonins are functionally similar to group I chaperonins but differ in structure and do not require a co-chaperonin. A significant number of bacteria and eukaryotes house multiple chaperonin and co-chaperonin proteins, many of which have acquired additional intracellular and extracellular biological functions. In some instances, co-chaperonins display contrasting functions to those of chaperonins. Human HSP60 (HSPD) continues to play a key role in the pathogenesis of many human diseases, in particular autoimmune diseases and cancer. A greater understanding of the fascinating roles of both intracellular and extracellular Hsp10 on cellular processes will accelerate the development of techniques to treat diseases associated with the chaperonin family.
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Affiliation(s)
- Aileen Boshoff
- Biotechnology Innovation Centre, Rhodes University, Makhanda/Grahamstown, South Africa.
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6
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Herranz-Montoya I, Park S, Djouder N. A comprehensive analysis of prefoldins and their implication in cancer. iScience 2021; 24:103273. [PMID: 34761191 PMCID: PMC8567396 DOI: 10.1016/j.isci.2021.103273] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
Prefoldins (PFDNs) are evolutionary conserved co-chaperones, initially discovered in archaea but universally present in eukaryotes. PFDNs are prevalently organized into hetero-hexameric complexes. Although they have been overlooked since their discovery and their functions remain elusive, several reports indicate they act as co-chaperones escorting misfolded or non-native proteins to group II chaperonins. Unlike the eukaryotic PFDNs which interact with cytoskeletal components, the archaeal PFDNs can bind and stabilize a wide range of substrates, possibly due to their great structural diversity. The discovery of the unconventional RPB5 interactor (URI) PFDN-like complex (UPC) suggests that PFDNs have versatile functions and are required for different cellular processes, including an important role in cancer. Here, we summarize their functions across different species. Moreover, a comprehensive analysis of PFDNs genomic alterations across cancer types by using large-scale cancer genomic data indicates that PFDNs are a new class of non-mutated proteins significantly overexpressed in some cancer types.
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Affiliation(s)
- Irene Herranz-Montoya
- Growth Factors, Nutrients and Cancer Group, Molecular Oncology Programme, Centro Nacional de Investigaciones Oncológicas, CNIO, Madrid 28029, Spain
| | - Solip Park
- Computational Cancer Genomics Group, Structural Biology Programme, Centro Nacional de Investigaciones Oncológicas, CNIO, Madrid 28029, Spain
| | - Nabil Djouder
- Growth Factors, Nutrients and Cancer Group, Molecular Oncology Programme, Centro Nacional de Investigaciones Oncológicas, CNIO, Madrid 28029, Spain
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7
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Nagaraju M, Kumar A, Jalaja N, Rao DM, Kishor PBK. Functional Exploration of Chaperonin (HSP60/10) Family Genes and their Abiotic Stress-induced Expression Patterns in Sorghum bicolor. Curr Genomics 2021; 22:137-152. [PMID: 34220300 PMCID: PMC8188580 DOI: 10.2174/1389202922666210324154336] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2020] [Revised: 01/05/2021] [Accepted: 01/22/2021] [Indexed: 11/30/2022] Open
Abstract
Background Sorghum, the C4 dry-land cereal, important for food, fodder, feed and fuel, is a model crop for abiotic stress tolerance with smaller genome size, genetic diversity, and bio-energy traits. The heat shock proteins/chaperonin 60s (HSP60/Cpn60s) assist the plastid proteins, and participate in the folding and aggregation of proteins. However, the functions of HSP60s in abiotic stress tolerance in Sorghum remain unclear. Methods Genome-wide screening and in silico characterization of SbHSP60s were carried out along with tissue and stress-specific expression analysis. Results A total of 36 HSP60 genes were identified in Sorghum bicolor. They were subdivided into 2 groups, the HSP60 and HSP10 co-chaperonins encoded by 30 and 6 genes, respectively. The genes are distributed on all the chromosomes, chromosome 1 being the hot spot with 9 genes. All the HSP60s were found hydrophilic and highly unstable. The HSP60 genes showed a large number of introns, the majority of them with more than 10. Among the 12 paralogs, only 1 was tandem and the remaining 11 segmental, indicating their role in the expansion of SbHSP60s. Majority of the SbHSP60 genes expressed uniformly in leaf while a moderate expression was observed in the root tissues, with the highest expression displayed by SbHSP60-1. From expression analysis, SbHSP60-3 for drought, SbHSP60-9 for salt, SbHSP60-9 and 24 for heat and SbHSP60-3, 9 and SbHSP10-2 have been found implicated for cold stress tolerance and appeared as the key regulatory genes. Conclusion This work paves the way for the utilization of chaperonin family genes for achieving abiotic stress tolerance in plants.
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Affiliation(s)
- M Nagaraju
- Department of Genetics, Osmania University, Hyderabad 500 007, India.,Biochemistry Division, National Institute of Nutrition (ICMR), Hyderabad 500 007, India
| | - Anuj Kumar
- Advance Center for Computational & Applied Biotechnology, Uttarakhand Council for Biotechnology (UCB), Silk Park, Prem Nagar, Dehradun 248 007, India
| | - N Jalaja
- Department of Biotechnology, Vignan's Foundation for Science, Technology and Research, Vadlamudi, Guntur 522 213, Andhra Pradesh, India
| | - D Manohar Rao
- Department of Genetics, Osmania University, Hyderabad 500 007, India
| | - P B Kavi Kishor
- Department of Biotechnology, Vignan's Foundation for Science, Technology and Research, Vadlamudi, Guntur 522 213, Andhra Pradesh, India
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8
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Poonia AK, Mishra SK, Sirohi P, Chaudhary R, Kanwar M, Germain H, Chauhan H. Overexpression of wheat transcription factor (TaHsfA6b) provides thermotolerance in barley. PLANTA 2020; 252:53. [PMID: 32945950 DOI: 10.1007/s00425-020-03457-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/02/2020] [Accepted: 08/28/2020] [Indexed: 05/22/2023]
Abstract
Overexpressing a heat shock factor gene (TaHsfA6bT) from wheat provides thermotolerance in barley by constitutive expression of heat and other abiotic stress-response genes. Temperature is one of the most crucial abiotic factors defining the yield potential of temperate cereal crops, such as barley. The regulators of heat shock response (HSR), heat stress transcription factors (Hsfs), modulate the transcription level of heat-responsive genes to protect the plants from heat stress. In this study, an Hsf from wheat (TaHsfA6b) is overexpressed in barley for providing thermotolerance. Transgenic barley lines overexpressing TaHsfA6b showed improvement in thermotolerance. The constitutive overexpression of a TaHsfA6b gene upregulated the expression of major heat shock proteins and other abiotic stress-responsive genes. RNA-seq and qRT-PCR analysis confirmed the upregulation of Hsps, chaperonins, DNAJ, LEA protein genes, and genes related to anti-oxidative enzymes in transgenic lines. Excessive generation and accumulation of reactive oxygen species (ROS) occurred in wild-type (WT) plants during heat stress; however, the transgenic lines reflected improved ROS homeostasis mechanisms, showing lesser ROS accumulation under high temperature. No negative phenotypic changes were observed in overexpression lines. These results suggest that TaHsfA6b is a regulator of HSR and its overexpression altered the expression patterns of some main stress-related genes and enhanced the thermotolerance of this cereal crop.
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Affiliation(s)
- Anuj Kumar Poonia
- Department of Biotechnology, Indian Institute of Technology Roorkee, Roorkee, 247667, India
| | - Sumit Kumar Mishra
- Department of Biotechnology, Indian Institute of Technology Roorkee, Roorkee, 247667, India
| | - Parul Sirohi
- Department of Biotechnology, Indian Institute of Technology Roorkee, Roorkee, 247667, India
- Department of Chemistry, Biochemistry and Physics, Université du Québec à Trois-Rivières, Trois-Rivières, QC, G9A 5H7, Canada
| | - Reeku Chaudhary
- Department of Biotechnology, Indian Institute of Technology Roorkee, Roorkee, 247667, India
| | - Meenakshi Kanwar
- Department of Biotechnology, Indian Institute of Technology Roorkee, Roorkee, 247667, India
| | - Hugo Germain
- Department of Chemistry, Biochemistry and Physics, Université du Québec à Trois-Rivières, Trois-Rivières, QC, G9A 5H7, Canada
| | - Harsh Chauhan
- Department of Biotechnology, Indian Institute of Technology Roorkee, Roorkee, 247667, India.
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OsCpn60β1 is Essential for Chloroplast Development in Rice ( Oryza sativa L.). Int J Mol Sci 2020; 21:ijms21114023. [PMID: 32512821 PMCID: PMC7313468 DOI: 10.3390/ijms21114023] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2020] [Revised: 06/01/2020] [Accepted: 06/02/2020] [Indexed: 01/03/2023] Open
Abstract
The chaperonin 60 (Cpn60) protein is of great importance to plants due to its involvement in modulating the folding of numerous chloroplast protein polypeptides. In chloroplasts, Cpn60 is differentiated into two subunit types—Cpn60α and Cpn60β and the rice genome encodes three α and three β plastid chaperonin subunits. However, the functions of Cpn60 family members in rice were poorly understood. In order to investigate the molecular mechanism of OsCpn60β1, we attempted to disrupt the OsCpn60β1 gene by CRISPR/Cas9-mediated targeted mutagenesis in this study. We succeeded in the production of homozygous OsCpn60β1 knockout rice plants. The OsCpn60β1 mutant displayed a striking albino leaf phenotype and was seedling lethal. Electron microscopy observation demonstrated that chloroplasts were severely disrupted in the OsCpn60β1 mutant. In addition, OsCpn60β1 was located in the chloroplast and OsCpn60β1 is constitutively expressed in various tissues particularly in the green tissues. The label-free qualitative proteomics showed that photosynthesis-related pathways and ribosomal pathways were significantly inhibited in OsCpn60β1 mutants. These results indicate that OsCpn60β1 is essential for chloroplast development in rice.
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10
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Zhang J, Xie M, Li M, Ding J, Pu Y, Bryan AC, Rottmann W, Winkeler KA, Collins CM, Singan V, Lindquist EA, Jawdy SS, Gunter LE, Engle NL, Yang X, Barry K, Tschaplinski TJ, Schmutz J, Tuskan GA, Muchero W, Chen J. Overexpression of a Prefoldin β subunit gene reduces biomass recalcitrance in the bioenergy crop Populus. PLANT BIOTECHNOLOGY JOURNAL 2020; 18:859-871. [PMID: 31498543 PMCID: PMC7004918 DOI: 10.1111/pbi.13254] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/20/2018] [Revised: 08/21/2019] [Accepted: 09/02/2019] [Indexed: 05/06/2023]
Abstract
Prefoldin (PFD) is a group II chaperonin that is ubiquitously present in the eukaryotic kingdom. Six subunits (PFD1-6) form a jellyfish-like heterohexameric PFD complex and function in protein folding and cytoskeleton organization. However, little is known about its function in plant cell wall-related processes. Here, we report the functional characterization of a PFD gene from Populus deltoides, designated as PdPFD2.2. There are two copies of PFD2 in Populus, and PdPFD2.2 was ubiquitously expressed with high transcript abundance in the cambial region. PdPFD2.2 can physically interact with DELLA protein RGA1_8g, and its subcellular localization is affected by the interaction. In P. deltoides transgenic plants overexpressing PdPFD2.2, the lignin syringyl/guaiacyl ratio was increased, but cellulose content and crystallinity index were unchanged. In addition, the total released sugar (glucose and xylose) amounts were increased by 7.6% and 6.1%, respectively, in two transgenic lines. Transcriptomic and metabolomic analyses revealed that secondary metabolic pathways, including lignin and flavonoid biosynthesis, were affected by overexpressing PdPFD2.2. A total of eight hub transcription factors (TFs) were identified based on TF binding sites of differentially expressed genes in Populus transgenic plants overexpressing PdPFD2.2. In addition, several known cell wall-related TFs, such as MYB3, MYB4, MYB7, TT8 and XND1, were affected by overexpression of PdPFD2.2. These results suggest that overexpression of PdPFD2.2 can reduce biomass recalcitrance and PdPFD2.2 is a promising target for genetic engineering to improve feedstock characteristics to enhance biofuel conversion and reduce the cost of lignocellulosic biofuel production.
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Affiliation(s)
- Jin Zhang
- Biosciences DivisionOak Ridge National LaboratoryOak RidgeTNUSA
- Center for Bioenergy InnovationOak Ridge National LaboratoryOak RidgeTNUSA
| | - Meng Xie
- Biosciences DivisionOak Ridge National LaboratoryOak RidgeTNUSA
- Center for Bioenergy InnovationOak Ridge National LaboratoryOak RidgeTNUSA
- Department of Plant SciencesUniversity of TennesseeKnoxvilleTNUSA
| | - Mi Li
- Chemical & Biomolecular EngineeringUniversity of TennesseeKnoxvilleTNUSA
| | - Jinhua Ding
- Chemical & Biomolecular EngineeringUniversity of TennesseeKnoxvilleTNUSA
- College of TextilesDonghua UniversityShanghaiChina
| | - Yunqiao Pu
- Biosciences DivisionOak Ridge National LaboratoryOak RidgeTNUSA
- Center for Bioenergy InnovationOak Ridge National LaboratoryOak RidgeTNUSA
| | | | | | | | | | - Vasanth Singan
- U.S. Department of Energy Joint Genome InstituteWalnut CreekCAUSA
| | | | - Sara S. Jawdy
- Biosciences DivisionOak Ridge National LaboratoryOak RidgeTNUSA
- Center for Bioenergy InnovationOak Ridge National LaboratoryOak RidgeTNUSA
| | - Lee E. Gunter
- Biosciences DivisionOak Ridge National LaboratoryOak RidgeTNUSA
- Center for Bioenergy InnovationOak Ridge National LaboratoryOak RidgeTNUSA
| | - Nancy L. Engle
- Biosciences DivisionOak Ridge National LaboratoryOak RidgeTNUSA
- Center for Bioenergy InnovationOak Ridge National LaboratoryOak RidgeTNUSA
| | - Xiaohan Yang
- Biosciences DivisionOak Ridge National LaboratoryOak RidgeTNUSA
- Center for Bioenergy InnovationOak Ridge National LaboratoryOak RidgeTNUSA
| | - Kerrie Barry
- U.S. Department of Energy Joint Genome InstituteWalnut CreekCAUSA
| | - Timothy J. Tschaplinski
- Biosciences DivisionOak Ridge National LaboratoryOak RidgeTNUSA
- Center for Bioenergy InnovationOak Ridge National LaboratoryOak RidgeTNUSA
| | - Jeremy Schmutz
- U.S. Department of Energy Joint Genome InstituteWalnut CreekCAUSA
- HudsonAlpha Institute for BiotechnologyHuntsvilleALUSA
| | - Gerald A. Tuskan
- Biosciences DivisionOak Ridge National LaboratoryOak RidgeTNUSA
- Center for Bioenergy InnovationOak Ridge National LaboratoryOak RidgeTNUSA
| | - Wellington Muchero
- Biosciences DivisionOak Ridge National LaboratoryOak RidgeTNUSA
- Center for Bioenergy InnovationOak Ridge National LaboratoryOak RidgeTNUSA
| | - Jin‐Gui Chen
- Biosciences DivisionOak Ridge National LaboratoryOak RidgeTNUSA
- Center for Bioenergy InnovationOak Ridge National LaboratoryOak RidgeTNUSA
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Altunoğlu YÇ, Keleş M, Can TH, Baloğlu MC. Identification of watermelon heat shock protein members and tissue-specific gene expression analysis under combined drought and heat stresses. ACTA ACUST UNITED AC 2019; 43:404-419. [PMID: 31892809 PMCID: PMC6911259 DOI: 10.3906/biy-1907-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Heat shock protein (Hsp) gene family members in the watermelon genome were identified and characterized by bioinformatics analysis. In addition, expression profiles of genes under combined drought and heat stress conditions were experimentally analyzed. In the watermelon genome, 39 genes belonging to the sHsp family, 101 genes belonging to the Hsp40 family, 23 genes belonging to the Hsp60 family, 12 genes belonging to the Hsp70 family, 6 genes belonging to the Hsp90 family, and 102 genes belonging to the Hsp100 family were found. It was also observed that the proteins in the same cluster in the phylogenetic trees had similar motif patterns. When the estimated 3-dimensional structures of the Hsp proteins were examined, it was determined that the α-helical structure was dominant in almost all families. The most orthologous relationship appeared to be between watermelon, soybean, and poplar in the ClaHsp gene families. For tissue-specific gene expression analysis under combined stress conditions, expression analysis of one representative Hsp gene each from root, stem, leaf, and shoot tissues was performed by real-time PCR. A significant increase was detected usually at 30 min in almost all tissues. This study provides extensive information for watermelon Hsps, and can enhance our knowledge about the relationships between Hsp genes and combined stresses.
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Affiliation(s)
- Yasemin Çelik Altunoğlu
- Department of Genetics and Bioengineering, Faculty of Engineering and Architecture, Kastamonu University, Kastamonu Turkey
| | - Merve Keleş
- Department of Genetics and Bioengineering, Faculty of Engineering and Architecture, Kastamonu University, Kastamonu Turkey
| | - Tevfik Hasan Can
- Department of Genetics and Bioengineering, Faculty of Engineering and Architecture, Kastamonu University, Kastamonu Turkey
| | - Mehmet Cengiz Baloğlu
- Department of Genetics and Bioengineering, Faculty of Engineering and Architecture, Kastamonu University, Kastamonu Turkey
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12
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Tiwari LD, Grover A. Cpn60β4 protein regulates growth and developmental cycling and has bearing on flowering time in Arabidopsis thaliana plants. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2019; 286:78-88. [PMID: 31300145 DOI: 10.1016/j.plantsci.2019.05.022] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/24/2019] [Revised: 05/25/2019] [Accepted: 05/28/2019] [Indexed: 06/10/2023]
Abstract
Chloroplastic Cpn60 proteins are type I chaperonins comprising of Cpn60α and Cpn60β subunits. Arabidopsis genome contains six entries in Cpn60 family, out of which two are for Cpn60α subunit and four for Cpn60β subunit. We noted that the cpn60β4 knockout mutant plants (T-DNA insertion salk_064887 line) differed from the wild type Col-0 plants in the developmental programming. cpn60β4 mutant plants showed early seed germination. Radical emergence, hypocotyl emergence and cotyledons opening were faster in cpn60β4 mutant plants than WT. Importantly, cpn60β4 mutant plants showed early-flowering phenotype. The number of flowers and siliques as well as weight of the seeds were higher in cpn60β4 mutant plants as compared to Col-0 plants. These effects were reverted to wild type like growth and developmental patterns when genomic fragment of Arabidopsis encompassing Cpn60β4 gene was complemented in the mutant background. The overexpression of Cpn60β4 gene using CaMV35 promoter in wild type background (OE-Cpn60β4) delayed the floral transition as against wild type plants. The plastid division were affected in cpn60β4 mutant plants compared to Col-0. The results of this study suggest that Cpn60β4 plays important role(s) in chloroplast development and is a key factor in plant growth, development and flowering in Arabidopsis.
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Affiliation(s)
- Lalit Dev Tiwari
- Department of Plant Molecular Biology, University of Delhi South Campus, New Delhi, 110021, India
| | - Anil Grover
- Department of Plant Molecular Biology, University of Delhi South Campus, New Delhi, 110021, India.
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Zhao Q, Zhang X, Sommer F, Ta N, Wang N, Schroda M, Cong Y, Liu C. Hetero-oligomeric CPN60 resembles highly symmetric group-I chaperonin structure revealed by Cryo-EM. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2019; 98:798-812. [PMID: 30735603 DOI: 10.1111/tpj.14273] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/30/2018] [Revised: 01/07/2019] [Accepted: 01/23/2019] [Indexed: 06/09/2023]
Abstract
The chloroplast chaperonin system is indispensable for the biogenesis of Rubisco, the key enzyme in photosynthesis. Using Chlamydomonas reinhardtii as a model system, we found that in vivo the chloroplast chaperonin consists of CPN60α, CPN60β1 and CPN60β2 and the co-chaperonin of the three subunits CPN20, CPN11 and CPN23. In Escherichia coli, CPN20 homo-oligomers and all possible other chloroplast co-chaperonin hetero-oligomers are functional, but only that consisting of CPN11/20/23-CPN60αβ1β2 can fully replace GroES/GroEL under stringent stress conditions. Endogenous CPN60 was purified and its stoichiometry was determined to be 6:2:6 for CPN60α:CPN60β1:CPN60β2. The cryo-EM structures of endogenous CPN60αβ1β2/ADP and CPN60αβ1β2/co-chaperonin/ADP were solved at resolutions of 4.06 and 3.82 Å, respectively. In both hetero-oligomeric complexes the chaperonin subunits within each ring are highly symmetric. Through hetero-oligomerization, the chloroplast co-chaperonin CPN11/20/23 forms seven GroES-like domains, which symmetrically interact with CPN60αβ1β2. Our structure also reveals an uneven distribution of roof-forming domains in the dome-shaped CPN11/20/23 co-chaperonin and potentially diversified surface properties in the folding cavity of the CPN60αβ1β2 chaperonin that might enable the chloroplast chaperonin system to assist in the folding of specific substrates.
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Affiliation(s)
- Qian Zhao
- State Key Laboratory of Plant Cell and Chromosome Engineering, Institute of Genetics and Developmental Biology, The Innovative Academy of Seed Design, Chinese Academy of Sciences, Beijing, 100101, China
- University of Chinese Academy of Sciences, Beijing, 100101, China
| | - Xiang Zhang
- National Center for Protein Science Shanghai, State Key Laboratory of Molecular Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Shanghai, 201210, China
- Shanghai Science Research Center, Chinese Academy of Sciences, Shanghai, 201210, China
| | - Frederik Sommer
- Shanghai Science Research Center, Chinese Academy of Sciences, Shanghai, 201210, China
| | - Na Ta
- State Key Laboratory of Plant Cell and Chromosome Engineering, Institute of Genetics and Developmental Biology, The Innovative Academy of Seed Design, Chinese Academy of Sciences, Beijing, 100101, China
- University of Chinese Academy of Sciences, Beijing, 100101, China
| | - Ning Wang
- State Key Laboratory of Plant Cell and Chromosome Engineering, Institute of Genetics and Developmental Biology, The Innovative Academy of Seed Design, Chinese Academy of Sciences, Beijing, 100101, China
- University of Chinese Academy of Sciences, Beijing, 100101, China
| | - Michael Schroda
- Molecular Biotechnology and Systems Biology, TU Kaiserslautern, Erwin-Schroedinger Str. 70, 67663, Kaiserslautern, Germany
| | - Yao Cong
- National Center for Protein Science Shanghai, State Key Laboratory of Molecular Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Shanghai, 201210, China
- Shanghai Science Research Center, Chinese Academy of Sciences, Shanghai, 201210, China
| | - Cuimin Liu
- State Key Laboratory of Plant Cell and Chromosome Engineering, Institute of Genetics and Developmental Biology, The Innovative Academy of Seed Design, Chinese Academy of Sciences, Beijing, 100101, China
- University of Chinese Academy of Sciences, Beijing, 100101, China
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Protein Changes in Response to Lead Stress of Lead-Tolerant and Lead-Sensitive Industrial Hemp Using SWATH Technology. Genes (Basel) 2019; 10:genes10050396. [PMID: 31121980 PMCID: PMC6562531 DOI: 10.3390/genes10050396] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2019] [Accepted: 05/20/2019] [Indexed: 11/17/2022] Open
Abstract
Hemp is a Pb-tolerant and Pb-accumulating plant and the study of its tolerance mechanisms could facilitate the breeding of hemp with enhanced Pb tolerance and accumulation. In the present study, we took advantage of sequential window acquisition of all theoretical mass spectra (SWATH) technology to study the difference in proteomics between the leaves of Pb-tolerant seed-type hemp variety Bamahuoma (BM) and the Pb-sensitive fiber-type hemp variety Yunma 1 (Y1) under Pb stress (3 g/kg soil). A total of 63 and 372 proteins differentially expressed under Pb stress relative to control conditions were identified with liquid chromatography electro spray ionization tandem mass spectrometry in BM and Y1, respectively; with each of these proteins being classified into 14 categories. Hemp adapted to Pb stress by: accelerating adenosine triphosphate (ATP) metabolism; enhancing respiration, light absorption and light energy transfer; promoting assimilation of intercellular nitrogen (N) and carbon (C); eliminating reactive oxygen species; regulating stomatal development and closure; improving exchange of water and CO2 in leaves; promoting intercellular transport; preventing aggregation of unfolded proteins; degrading misfolded proteins; and increasing the transmembrane transport of ATP in chloroplasts. Our results provide an important reference protein and gene information for future molecular studies into the resistance and accumulation of Pb in hemp.
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Hsu YW, Juan CT, Wang CM, Jauh GY. Mitochondrial Heat Shock Protein 60s Interact with What's This Factor 9 to Regulate RNA Splicing of ccmFC and rpl2. PLANT & CELL PHYSIOLOGY 2019; 60:116-125. [PMID: 30289547 DOI: 10.1093/pcp/pcy199] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/21/2018] [Accepted: 09/30/2018] [Indexed: 06/08/2023]
Abstract
Mitochondrial intron splicing is a plant-specific feature that was acquired during the co-evolution of eukaryotic host cells and a-proteobacteria. The elimination of these introns is facilitated by mitochondrial-targeted proteins encoded by its host, nucleus. What's this factor 9 (WTF9), a nuclear-encoded plant organelle RNA recognition (PORR) protein, is involved in the splicing of the mitochondrial group II introns rpl2 and ccmFC. Disruption of WTF9 causes developmental defects associated with the loss of Cyt c and Cyt c1 in Arabidopsis. In the present study, using a co-immunoprecipitation assay, we found that HSP60s interacted with WTF9, which was further confirmed by a pull-down assay. HSP60s are molecular chaperones that assist with protein folding in both eukaryotic and prokaryotic cells. However, accumulating evidence suggests that HSP60s also participate in other biological functions such as RNA metabolism and RNA protection. In this study, we found that consistently with their interaction with WTF9, HSP60s interacted with 48 nucleotides of the ccmFC intron. In mutant studies, the double mutant hsp60-3a1hsp60-3b1 exhibited a small stature phenotype and reduced splicing efficiency for rpl2 and ccmFC. These observations were similar to those in wtf9 mutants and suggest that HSP60s are involved in the RNA splicing of rpl2 and ccmFC introns in mitochondria. Our findings suggest that HSP60s participate in mitochondrial RNA splicing through their RNA-binding ability.
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Affiliation(s)
- Ya-Wen Hsu
- Institute of Plant and Microbial Biology,Academia Sinica, 128 Sec. 2, Academia Rd, Nankang, Taipei, Taiwan, ROC
| | - Chien-Ta Juan
- Institute of Plant and Microbial Biology,Academia Sinica, 128 Sec. 2, Academia Rd, Nankang, Taipei, Taiwan, ROC
| | - Chung-Min Wang
- Institute of Plant and Microbial Biology,Academia Sinica, 128 Sec. 2, Academia Rd, Nankang, Taipei, Taiwan, ROC
| | - Guang-Yuh Jauh
- Institute of Plant and Microbial Biology,Academia Sinica, 128 Sec. 2, Academia Rd, Nankang, Taipei, Taiwan, ROC
- Biotechnology Center, National Chung-Hsing University, Taichung 402, Taiwan, ROC
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Ansari MY, Mande SC. A Glimpse Into the Structure and Function of Atypical Type I Chaperonins. Front Mol Biosci 2018; 5:31. [PMID: 29696145 PMCID: PMC5904260 DOI: 10.3389/fmolb.2018.00031] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2018] [Accepted: 03/21/2018] [Indexed: 12/22/2022] Open
Abstract
Chaperonins are a subclass of molecular chaperones that assist cellular proteins to fold and assemble into their native shape. Much work has been done on Type I chaperonins, which has elucidated their elegant mechanism. Some debate remains about the details in these mechanisms, but nonetheless the roles of these in helping protein folding have been understood in great depth. In this review we discuss the known functions of atypical Type I chaperonins, highlighting evolutionary aspects that might lead chaperonins to perform alternate functions.
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17
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Vitlin Gruber A, Feiz L. Rubisco Assembly in the Chloroplast. Front Mol Biosci 2018; 5:24. [PMID: 29594130 PMCID: PMC5859369 DOI: 10.3389/fmolb.2018.00024] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2017] [Accepted: 02/27/2018] [Indexed: 01/13/2023] Open
Abstract
Ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) catalyzes the rate-limiting step in the Calvin-Benson cycle, which transforms atmospheric carbon into a biologically useful carbon source. The slow catalytic rate of Rubisco and low substrate specificity necessitate the production of high levels of this enzyme. In order to engineer a more efficient plant Rubisco, we need to better understand its folding and assembly process. Form I Rubisco, found in green algae and vascular plants, is a hexadecamer composed of 8 large subunits (RbcL), encoded by the chloroplast genome and 8 small, nuclear-encoded subunits (RbcS). Unlike its cyanobacterial homolog, which can be reconstituted in vitro or in E. coli, assisted by bacterial chaperonins (GroEL-GroES) and the RbcX chaperone, biogenesis of functional chloroplast Rubisco requires Cpn60-Cpn20, the chloroplast homologs of GroEL-GroES, and additional auxiliary factors, including Rubisco accumulation factor 1 (Raf1), Rubisco accumulation factor 2 (Raf2) and Bundle sheath defective 2 (Bsd2). The discovery and characterization of these factors paved the way for Arabidopsis Rubisco assembly in E. coli. In the present review, we discuss the uniqueness of hetero-oligomeric chaperonin complex for RbcL folding, as well as the sequential or concurrent actions of the post-chaperonin chaperones in holoenzyme assembly. The exact stages at which each assembly factor functions are yet to be determined. Expression of Arabidopsis Rubisco in E. coli provided some insight regarding the potential roles for Raf1 and RbcX in facilitating RbcL oligomerization, for Bsd2 in stabilizing the oligomeric core prior to holoenzyme assembly, and for Raf2 in interacting with both RbcL and RbcS. In the long term, functional characterization of each known factor along with the potential discovery and characterization of additional factors will set the stage for designing more efficient plants, with a greater biomass, for use in biofuels and sustenance.
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Affiliation(s)
- Anna Vitlin Gruber
- Department of Molecular, Cell and Developmental Biology, University of California, Los Angeles, Los Angeles, CA, United States
| | - Leila Feiz
- Boyce Thompson Institute, Cornell University, Ithaca, NY, United States
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18
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Vitlin Gruber A, Vugman M, Azem A, Weiss CE. Reconstitution of Pure Chaperonin Hetero-Oligomer Preparations in Vitro by Temperature Modulation. Front Mol Biosci 2018; 5:5. [PMID: 29435453 PMCID: PMC5790771 DOI: 10.3389/fmolb.2018.00005] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2017] [Accepted: 01/11/2018] [Indexed: 01/13/2023] Open
Abstract
Chaperonins are large, essential, oligomers that facilitate protein folding in chloroplasts, mitochondria, and eubacteria. Plant chloroplast chaperonins are comprised of multiple homologous subunits that exhibit unique properties. We previously characterized homogeneous, reconstituted, chloroplast-chaperonin oligomers in vitro, each composed of one of three highly homologous beta subunits from A. thaliana. In the current work, we describe alpha-type subunits from the same species and investigate their interaction with β subtypes. Neither alpha subunit was capable of forming higher-order oligomers on its own. When combined with β subunits in the presence of Mg-ATP, only the α2 subunit was able to form stable functional hetero-oligomers, which were capable of refolding denatured protein with native chloroplast co-chaperonins. Since β oligomers were able to oligomerize in the absence of α, we sought conditions under which αβ hetero-oligomers could be produced without contamination of β homo-oligomers. We found that β2 subunits are unable to oligomerize at low temperatures and used this property to obtain homogenous preparations of functional α2β2 hetero-oligomers. The results of this study highlight the importance of reaction conditions such as temperature and concentration for the reconstitution of chloroplast chaperonin oligomers in vitro.
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Affiliation(s)
- Anna Vitlin Gruber
- Department of Molecular, Cell and Developmental Biology, University of California, Los Angeles, Los Angeles, CA, United States
| | - Milena Vugman
- Department of Biochemistry and Molecular Biology, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel
| | - Abdussalam Azem
- Department of Biochemistry and Molecular Biology, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel
| | - Celeste E Weiss
- Department of Biochemistry and Molecular Biology, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel
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19
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Zhao Q, Liu C. Chloroplast Chaperonin: An Intricate Protein Folding Machine for Photosynthesis. Front Mol Biosci 2018; 4:98. [PMID: 29404339 PMCID: PMC5780408 DOI: 10.3389/fmolb.2017.00098] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2017] [Accepted: 12/28/2017] [Indexed: 11/13/2022] Open
Abstract
Group I chaperonins are large cylindrical-shaped nano-machines that function as a central hub in the protein quality control system in the bacterial cytosol, mitochondria and chloroplasts. In chloroplasts, proteins newly synthesized by chloroplast ribosomes, unfolded by diverse stresses, or translocated from the cytosol run the risk of aberrant folding and aggregation. The chloroplast chaperonin system assists these proteins in folding into their native states. A widely known protein folded by chloroplast chaperonin is the large subunit of ribulose 1,5-bisphosphate carboxylase/oxygenase (Rubisco), an enzyme responsible for the fixation of inorganic CO2 into organic carbohydrates during photosynthesis. Chloroplast chaperonin was initially identified as a Rubisco-binding protein. All photosynthetic eucaryotes genomes encode multiple chaperonin genes which can be divided into α and β subtypes. Unlike the homo-oligomeric chaperonins from bacteria and mitochondria, chloroplast chaperonins are more complex and exists as intricate hetero-oligomers containing both subtypes. The Group I chaperonin requires proper interaction with a detachable lid-like co-chaperonin in the presence of ATP and Mg2+ for substrate encapsulation and conformational transition. Besides the typical Cpn10-like co-chaperonin, a unique co-chaperonin consisting of two tandem Cpn10-like domains joined head-to-tail exists in chloroplasts. Since chloroplasts were proposed as sensors to various environmental stresses, this diversified chloroplast chaperonin system has the potential to adapt to complex conditions by accommodating specific substrates or through regulation at both the transcriptional and post-translational levels. In this review, we discuss recent progress on the unique structure and function of the chloroplast chaperonin system based on model organisms Chlamydomonas reinhardtii and Arabidopsis thaliana. Knowledge of the chloroplast chaperonin system may ultimately lead to successful reconstitution of eukaryotic Rubisco in vitro.
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Affiliation(s)
- Qian Zhao
- State Key Laboratory of Plant Cell and Chromosome Engineering, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Cuimin Liu
- State Key Laboratory of Plant Cell and Chromosome Engineering, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China
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20
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Molecular Chaperones: Structure-Function Relationship and their Role in Protein Folding. REGULATION OF HEAT SHOCK PROTEIN RESPONSES 2018. [DOI: 10.1007/978-3-319-74715-6_8] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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21
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Nakamoto H, Kojima K. Non-housekeeping, non-essential GroEL (chaperonin) has acquired novel structure and function beneficial under stress in cyanobacteria. PHYSIOLOGIA PLANTARUM 2017; 161:296-310. [PMID: 28597961 DOI: 10.1111/ppl.12595] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/03/2017] [Revised: 05/17/2017] [Accepted: 05/30/2017] [Indexed: 06/07/2023]
Abstract
GroELs which are prokaryotic members of the chaperonin (Cpn)/Hsp60 family are molecular chaperones of which Escherichia coli GroEL is a model for subsequent research. The majority of bacterial species including E. coli and Bacillus subtilis have only one essential groEL gene that forms an operon with the co-chaperone groES gene. In contrast to these model bacteria, two or three groEL genes exist in cyanobacterial genomes. One of them, groEL2, does not form an operon with the groES gene, whereas the other(s) does. In the case of cyanobacteria containing two GroEL homologs, one of the GroELs, GroEL1, substitutes for the native GroEL in an E. coli cell, but GroEL2 does not. Unlike the E. coli GroEL, GroEL2 is not essential, but it plays an important role which is not substitutable by GroEL1 under stress. Regulation of expression and biochemical properties of GroEL2 are different/diversified from GroEL1 and E. coli GroEL in many aspects. We postulate that the groEL2 gene has acquired a novel, beneficial function especially under stresses and become preserved by natural selection, with the groEL1 gene retaining the original, house-keeping function. In this review, we will focus on difference between the two GroELs in cyanobacteria, and divergence of GroEL2 from the E. coli GroEL. We will also compare cyanobacterial GroELs with the chloroplast Cpns (60α and 60β) which are thought to be evolved from the cyanobacterial GroEL1. Chloroplast Cpns appear to follow the different path from cyanobacterial GroELs in the evolution after gene duplication of the corresponding ancestral groEL gene.
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Affiliation(s)
- Hitoshi Nakamoto
- Department of Biochemistry and Molecular Biology, Graduate School of Science and Engineering, Saitama University, Saitama, Japan
| | - Kouji Kojima
- Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya, Japan
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22
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Ke X, Zou W, Ren Y, Wang Z, Li J, Wu X, Zhao J. Functional divergence of chloroplast Cpn60α subunits during Arabidopsis embryo development. PLoS Genet 2017; 13:e1007036. [PMID: 28961247 PMCID: PMC5636168 DOI: 10.1371/journal.pgen.1007036] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2017] [Revised: 10/11/2017] [Accepted: 09/20/2017] [Indexed: 02/03/2023] Open
Abstract
Chaperonins are a class of molecular chaperones that assist in the folding and assembly of a wide range of substrates. In plants, chloroplast chaperonins are composed of two different types of subunits, Cpn60α and Cpn60β, and duplication of Cpn60α and Cpn60β genes occurs in a high proportion of plants. However, the importance of multiple Cpn60α and Cpn60β genes in plants is poorly understood. In this study, we found that loss-of-function of CPNA2 (AtCpn60α2), a gene encoding the minor Cpn60α subunit in Arabidopsis thaliana, resulted in arrested embryo development at the globular stage, whereas the other AtCpn60α gene encoding the dominant Cpn60α subunit, CPNA1 (AtCpn60α1), mainly affected embryonic cotyledon development at the torpedo stage and thereafter. Further studies demonstrated that CPNA2 can form a functional chaperonin with CPNB2 (AtCpn60β2) and CPNB3 (AtCpn60β3), while the functional partners of CPNA1 are CPNB1 (AtCpn60β1) and CPNB2. We also revealed that the functional chaperonin containing CPNA2 could assist the folding of a specific substrate, KASI (β-ketoacyl-[acyl carrier protein] synthase I), and that the KASI protein level was remarkably reduced due to loss-of-function of CPNA2. Furthermore, the reduction in the KASI protein level was shown to be the possible cause for the arrest of cpna2 embryos. Our findings indicate that the two Cpn60α subunits in Arabidopsis play different roles during embryo development through forming distinct chaperonins with specific AtCpn60β to assist the folding of particular substrates, thus providing novel insights into functional divergence of Cpn60α subunits in plants. Chaperonins are large oligomeric complexes that are involved in the folding and assembly of numerous proteins in various species. In contrast to other types of chaperonins, chloroplast chaperonins are characterized by the hetero-oligomeric structure composed of two unique types of subunits, Cpn60α and Cpn60β, each of which is present in two or more paralogous forms in most of higher plants. However, the functional significance underlying the wide array of subunit types and complex oligomeric arrangement remains largely unknown. Here, we investigated the role of the minor Cpn60α subunit AtCpn60α2 in Arabidopsis embryo development, and found that AtCpn60α2 is important for the transition of globular embryos to heart-shaped embryos, whereas loss of the dominant Cpn60α subunit AtCpn60α1 affects embryonic cotyledon development. Further studies demonstrated that AtCpn60α2 could form functional chaperonins with AtCpn60β2 and AtCpn60β3 to specifically assist in folding of the substrate KASI, which is important for the formation of heart-shaped embryos. Our results suggest that duplication of Cpn60α genes in higher plants can increase the potential number of chloroplast chaperonin substrates and provide chloroplast chaperonins with more roles in plant growth and development, thus revealing the relationship between duplication and functional specialization of chaperonin genes.
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Affiliation(s)
- Xiaolong Ke
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan, China
| | - Wenxuan Zou
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan, China
| | - Yafang Ren
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan, China
| | - Zhiqin Wang
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan, China
| | - Jin Li
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan, China
| | - Xuan Wu
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan, China
| | - Jie Zhao
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan, China
- * E-mail:
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23
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Weiss C, Jebara F, Nisemblat S, Azem A. Dynamic Complexes in the Chaperonin-Mediated Protein Folding Cycle. Front Mol Biosci 2016; 3:80. [PMID: 28008398 PMCID: PMC5143341 DOI: 10.3389/fmolb.2016.00080] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2016] [Accepted: 11/23/2016] [Indexed: 11/13/2022] Open
Abstract
The GroEL–GroES chaperonin system is probably one of the most studied chaperone systems at the level of the molecular mechanism. Since the first reports of a bacterial gene involved in phage morphogenesis in 1972, these proteins have stimulated intensive research for over 40 years. During this time, detailed structural and functional studies have yielded constantly evolving concepts of the chaperonin mechanism of action. Despite of almost three decades of research on this oligomeric protein, certain aspects of its function remain controversial. In this review, we highlight one central aspect of its function, namely, the active intermediates of its reaction cycle, and present how research to this day continues to change our understanding of chaperonin-mediated protein folding.
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Affiliation(s)
- Celeste Weiss
- George S. Weiss Faculty of Life Sciences, Department of Biochemistry and Molecular Biology, Tel Aviv University Tel Aviv, Israel
| | - Fady Jebara
- George S. Weiss Faculty of Life Sciences, Department of Biochemistry and Molecular Biology, Tel Aviv University Tel Aviv, Israel
| | - Shahar Nisemblat
- George S. Weiss Faculty of Life Sciences, Department of Biochemistry and Molecular Biology, Tel Aviv University Tel Aviv, Israel
| | - Abdussalam Azem
- George S. Weiss Faculty of Life Sciences, Department of Biochemistry and Molecular Biology, Tel Aviv University Tel Aviv, Israel
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Molecular cloning, characterization and expression analysis of a heat shock protein 10 (Hsp10) from Pennisetum glaucum (L.), a C4 cereal plant from the semi-arid tropics. Mol Biol Rep 2016; 43:861-70. [PMID: 27206926 DOI: 10.1007/s11033-016-4012-0] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2016] [Accepted: 05/12/2016] [Indexed: 01/13/2023]
Abstract
Heat shock proteins (Hsp10) belong to the ubiquitous family of heat-shock molecular chaperones found in the organelles of both prokaryotes and eukaryotes. Chaperonins assist the folding of nascent and stress-destabilized proteins. A cDNA clone encoding a 10 kDa Hsp was isolated from pearl millet, Pennisetum glaucum (L.) by screening a heat stress cDNA library. The fulllength PgHsp10 cDNA consisted of 297 bp open reading frame (ORF) encoding a 98 amino acid polypeptide with a predicted molecular mass of 10.61 kDa and an estimated isoelectric point (pI) of 7.95. PgHsp10 shares 70-98 % sequence identity with other plant homologs. Phylogenetic analysis revealed that PgHsp10 is evolutionarily close to the maize Hsp10 homolog. The predicted 3D model confirmed a conserved eight-stranded ß-barrel with active site between the ß-barrel comprising of eight-strands, with conserved domain VLLPEYGG sandwiched between two ß-sheets. The gene consisted of 3 exons and 2 introns, while the position and phasing of these introns were conserved similar to other plant Hsp10 family genes. In silico analysis of the promoter region of PgHsp10 presented several distinct set of cis-elements and transcription factor binding sites. Quantitative RT-PCR analysis showed that PgHsp10 gene was differentially expressed in response to abiotic stresses with the highest level of expression under heat stress conditions. Results of this study provide useful information regarding the role of chaperonins in stress regulation and generated leads for further elucidation of their function in plant stress tolerance.
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Structural insight into the cooperation of chloroplast chaperonin subunits. BMC Biol 2016; 14:29. [PMID: 27072913 PMCID: PMC4828840 DOI: 10.1186/s12915-016-0251-8] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2016] [Accepted: 03/29/2016] [Indexed: 11/10/2022] Open
Abstract
Background Chloroplast chaperonin, consisting of multiple subunits, mediates folding of the highly abundant protein Rubisco with the assistance of co-chaperonins. ATP hydrolysis drives the chaperonin allosteric cycle to assist substrate folding and promotes disassembly of chloroplast chaperonin. The ways in which the subunits cooperate during this cycle remain unclear. Results Here, we report the first crystal structure of Chlamydomonas chloroplast chaperonin homo-oligomer (CPN60β1) at 3.8 Å, which shares structural topology with typical type I chaperonins but with looser compaction, and possesses a larger central cavity, less contact sites and an enlarged ATP binding pocket compared to GroEL. The overall structure of Cpn60 resembles the GroEL allosteric intermediate state. Moreover, two amino acid (aa) residues (G153, G154) conserved among Cpn60s are involved in ATPase activity regulated by co-chaperonins. Domain swapping analysis revealed that the monomeric state of CPN60α is controlled by its equatorial domain. Furthermore, the C-terminal segment (aa 484–547) of CPN60β influenced oligomer disassembly and allosteric rearrangement driven by ATP hydrolysis. The entire equatorial domain and at least one part of the intermediate domain from CPN60α are indispensable for functional cooperation with CPN60β1, and this functional cooperation is strictly dependent on a conserved aa residue (E461) in the CPN60α subunit. Conclusions The first crystal structure of Chlamydomonas chloroplast chaperonin homo-oligomer (CPN60β1) is reported. The equatorial domain maintained the monomeric state of CPN60α and the C-terminus of CPN60β affected oligomer disassembly driven by ATP. The cooperative roles of CPN60 subunits were also established. Electronic supplementary material The online version of this article (doi:10.1186/s12915-016-0251-8) contains supplementary material, which is available to authorized users.
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Cao J. Analysis of the Prefoldin Gene Family in 14 Plant Species. FRONTIERS IN PLANT SCIENCE 2016; 7:317. [PMID: 27014333 PMCID: PMC4792155 DOI: 10.3389/fpls.2016.00317] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/27/2015] [Accepted: 02/29/2016] [Indexed: 05/03/2023]
Abstract
Prefoldin is a hexameric molecular chaperone complex present in all eukaryotes and archaea. The evolution of this gene family in plants is unknown. Here, I identified 140 prefoldin genes in 14 plant species. These prefoldin proteins were divided into nine groups through phylogenetic analysis. Highly conserved gene organization and motif distribution exist in each prefoldin group, implying their functional conservation. I also observed the segmental duplication of maize prefoldin gene family. Moreover, a few functional divergence sites were identified within each group pairs. Functional network analyses identified 78 co-expressed genes, and most of them were involved in carrying, binding and kinase activity. Divergent expression profiles of the maize prefoldin genes were further investigated in different tissues and development periods and under auxin and some abiotic stresses. I also found a few cis-elements responding to abiotic stress and phytohormone in the upstream sequences of the maize prefoldin genes. The results provided a foundation for exploring the characterization of the prefoldin genes in plants and will offer insights for additional functional studies.
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Nandi SK, Chakraborty A, Panda AK, Biswas A. Conformational perturbation, hydrophobic interactions and oligomeric association are responsible for the enhanced chaperone function of Mycobacterium leprae HSP18 under pre-thermal condition. RSC Adv 2016. [DOI: 10.1039/c6ra00167j] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Chaperone function of HSP18 is enhanced upon pre-heating at 60 °C and above which may be due to structural alterations.
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Affiliation(s)
- Sandip Kumar Nandi
- School of Basic Sciences
- Indian Institute of Technology Bhubaneswar
- Bhubaneswar-751 013
- India
| | - Ayon Chakraborty
- School of Basic Sciences
- Indian Institute of Technology Bhubaneswar
- Bhubaneswar-751 013
- India
| | - Alok Kumar Panda
- School of Basic Sciences
- Indian Institute of Technology Bhubaneswar
- Bhubaneswar-751 013
- India
| | - Ashis Biswas
- School of Basic Sciences
- Indian Institute of Technology Bhubaneswar
- Bhubaneswar-751 013
- India
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Bai C, Guo P, Zhao Q, Lv Z, Zhang S, Gao F, Gao L, Wang Y, Tian Z, Wang J, Yang F, Liu C. Protomer Roles in Chloroplast Chaperonin Assembly and Function. MOLECULAR PLANT 2015; 8:1478-92. [PMID: 26057234 DOI: 10.1016/j.molp.2015.06.002] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/30/2015] [Revised: 05/10/2015] [Accepted: 06/03/2015] [Indexed: 05/13/2023]
Abstract
The individual roles of three chloroplast CPN60 protomers (CPN60α, CPN60β1, and CPN60β2) and whether and how they are assembled into functional chaperonin complexes are investigated in Chlamydomonas reinhardtii. Protein complexes containing all three potential subunits were identified in Chlamydomonas, and their co-expression in Escherichia coli yielded a homogeneous population of oligomers containing all three subunits (CPN60αβ1β2), with a molecular weight consistent with a tetradecameric structure. While homo-oligomers of CPN60β could form, they were dramatically reduced when CPN60α was present and homo-oligomers of CPN60β2 were readily changed into hetero-oligomers in the presence of ATP and other protomers. ATP hydrolysis caused CPN60 oligomers to disassemble and drove the purified protomers to reconstitute oligomers in vitro, suggesting that the dynamic nature of CPN60 oligomers is dependent on ATP. Only hetero-oligomeric CPN60αβ1β2, containing CPN60α, CPN60β1, and CPN60β2 subunits in a 5:6:3 ratio, cooperated functionally with GroES. The combination of CPN60α and CPN60β subunits, but not the individual subunits alone, complemented GroEL function in E. coli with subunit recognition specificity. Down-regulation of the CPN60α subunit in Chlamydomonas resulted in a slow growth defect and an inability to grow autotrophically, indicating the essential role of CPN60α in vivo.
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Affiliation(s)
- Cuicui Bai
- State Key Laboratory of Plant Cell and Chromosome Engineering, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100101, China
| | - Peng Guo
- State Key Laboratory of Plant Cell and Chromosome Engineering, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100101, China
| | - Qian Zhao
- State Key Laboratory of Plant Cell and Chromosome Engineering, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100101, China
| | - Zongyang Lv
- State Key Laboratory of Plant Cell and Chromosome Engineering, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
| | - Shijia Zhang
- State Key Laboratory of Plant Cell and Chromosome Engineering, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100101, China
| | - Fei Gao
- State Key Laboratory of Plant Cell and Chromosome Engineering, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
| | - Liyan Gao
- Key Laboratory of Molecular Development Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
| | - Yingchun Wang
- Key Laboratory of Molecular Development Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
| | - Zhixi Tian
- State Key Laboratory of Plant Cell and Chromosome Engineering, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
| | - Jifeng Wang
- Laboratory of Protein and Peptide Pharmaceuticals and Laboratory of Proteomics, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
| | - Fuquan Yang
- Laboratory of Protein and Peptide Pharmaceuticals and Laboratory of Proteomics, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
| | - Cuimin Liu
- State Key Laboratory of Plant Cell and Chromosome Engineering, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China.
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Guo P, Jiang S, Bai C, Zhang W, Zhao Q, Liu C. Asymmetric functional interaction between chaperonin and its plastidic cofactors. FEBS J 2015; 282:3959-70. [DOI: 10.1111/febs.13390] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2015] [Revised: 07/07/2015] [Accepted: 07/30/2015] [Indexed: 01/12/2023]
Affiliation(s)
- Peng Guo
- State Key Laboratory of Plant Cell and Chromosome Engineering; Institute of Genetics and Developmental Biology; Chinese Academy of Sciences; Beijing China
- University of Chinese Academy of Sciences; Beijing China
| | - Shan Jiang
- State Key Laboratory of Plant Cell and Chromosome Engineering; Institute of Genetics and Developmental Biology; Chinese Academy of Sciences; Beijing China
- University of Chinese Academy of Sciences; Beijing China
| | - Cuicui Bai
- State Key Laboratory of Plant Cell and Chromosome Engineering; Institute of Genetics and Developmental Biology; Chinese Academy of Sciences; Beijing China
- University of Chinese Academy of Sciences; Beijing China
| | - Wenjuan Zhang
- State Key Laboratory of Plant Cell and Chromosome Engineering; Institute of Genetics and Developmental Biology; Chinese Academy of Sciences; Beijing China
| | - Qian Zhao
- State Key Laboratory of Plant Cell and Chromosome Engineering; Institute of Genetics and Developmental Biology; Chinese Academy of Sciences; Beijing China
- University of Chinese Academy of Sciences; Beijing China
| | - Cuimin Liu
- State Key Laboratory of Plant Cell and Chromosome Engineering; Institute of Genetics and Developmental Biology; Chinese Academy of Sciences; Beijing China
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Fragkostefanakis S, Simm S, Paul P, Bublak D, Scharf KD, Schleiff E. Chaperone network composition in Solanum lycopersicum explored by transcriptome profiling and microarray meta-analysis. PLANT, CELL & ENVIRONMENT 2015; 38:693-709. [PMID: 25124075 DOI: 10.1111/pce.12426] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/09/2014] [Accepted: 08/05/2014] [Indexed: 05/28/2023]
Abstract
Heat shock proteins (Hsps) are molecular chaperones primarily involved in maintenance of protein homeostasis. Their function has been best characterized in heat stress (HS) response during which Hsps are transcriptionally controlled by HS transcription factors (Hsfs). The role of Hsfs and Hsps in HS response in tomato was initially examined by transcriptome analysis using the massive analysis of cDNA ends (MACE) method. Approximately 9.6% of all genes expressed in leaves are enhanced in response to HS, including a subset of Hsfs and Hsps. The underlying Hsp-Hsf networks with potential functions in stress responses or developmental processes were further explored by meta-analysis of existing microarray datasets. We identified clusters with differential transcript profiles with respect to abiotic stresses, plant organs and developmental stages. The composition of two clusters points towards two major chaperone networks. One cluster consisted of constitutively expressed plastidial chaperones and other genes involved in chloroplast protein homeostasis. The second cluster represents genes strongly induced by heat, drought and salinity stress, including HsfA2 and many stress-inducible chaperones, but also potential targets of HsfA2 not related to protein homeostasis. This observation attributes a central regulatory role to HsfA2 in controlling different aspects of abiotic stress response and tolerance in tomato.
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Affiliation(s)
- Sotirios Fragkostefanakis
- Department of Biosciences, Molecular Cell Biology of Plants, Goethe University, 60438, Frankfurt/Main, Germany; Cluster of Excellence Frankfurt, Goethe University, 60438, Frankfurt/Main, Germany
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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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Abstract
Co-chaperonins function together with chaperonins to mediate ATP-dependant protein folding in a variety of cellular compartments. GroEL and its co-chaperonin GroES are the only essential chaperones in Escherichia coli and are the archetypal members of this family of protein folding machines. The unique mechanism used by GroEL and GroES to drive protein folding is embedded in the complex architecture of double-ringed complexes, forming two central chambers that undergo structural rearrangements as part of the folding mechanism. GroES forms a lid over the chamber, and in doing so dislodges bound substrate into the chamber, thereby allowing non-native proteins to fold in isolation. GroES also modulates allosteric transitions of GroEL. A significant number of bacteria and eukaryotes house multiple chaperonin and co-chaperonin proteins, many of which have acquired additional intracellular and extracellular biological functions. In some instances co-chaperonins display contrasting functions to those of chaperonins. Human Hsp60 continues to play a key role in the pathogenesis of many human diseases, in particular autoimmune diseases and cancer. A greater understanding of the fascinating roles of both intracellular and extracellular Hsp10, in addition to its role as a co-chaperonin, on cellular processes will accelerate the development of techniques to treat diseases associated with the chaperonin family.
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Affiliation(s)
- Aileen Boshoff
- Biomedical Biotechnology Research Unit (BioBRU), Biotechnology Innovation Centre, Rhodes University, PO Box 94, 6140, Grahamstown, South Africa,
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Vitlin Gruber A, Zizelski G, Azem A, Weiss C. The Cpn10(1) co-chaperonin of A. thaliana functions only as a hetero-oligomer with Cpn20. PLoS One 2014; 9:e113835. [PMID: 25419702 PMCID: PMC4242682 DOI: 10.1371/journal.pone.0113835] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2014] [Accepted: 10/31/2014] [Indexed: 12/16/2022] Open
Abstract
The A. thaliana genome encodes five co-chaperonin homologs, three of which are destined to the chloroplast. Two of the proteins, Cpn10(2) and Cpn20, form functional homo-oligomers in vitro. In the current work, we present data on the structure and function of the third A. thaliana co-chaperonin, which exhibits unique properties. We found that purified recombinant Cpn10(1) forms inactive dimers in solution, in contrast to the active heptamers that are formed by canonical Cpn10s. Additionally, our data demonstrate that Cpn10(1) is capable of assembling into active hetero-oligomers together with Cpn20. This finding was reinforced by the formation of active co-chaperonin species upon mixing an inactive Cpn20 mutant with the inactive Cpn10(1). The present study constitutes the first report of a higher plant Cpn10 subunit that is able to function only upon formation of hetero-oligomers with other co-chaperonins.
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Affiliation(s)
- Anna Vitlin Gruber
- Department of Biochemistry and Molecular Biology, Tel Aviv University, Tel Aviv, Israel
| | - Gal Zizelski
- Department of Biochemistry and Molecular Biology, Tel Aviv University, Tel Aviv, Israel
| | - Abdussalam Azem
- Department of Biochemistry and Molecular Biology, Tel Aviv University, Tel Aviv, Israel
- * E-mail:
| | - Celeste Weiss
- Department of Biochemistry and Molecular Biology, Tel Aviv University, Tel Aviv, Israel
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Joshi J, Mueller-Cajar O, Tsai YCC, Hartl FU, Hayer-Hartl M. Role of small subunit in mediating assembly of red-type form I Rubisco. J Biol Chem 2014; 290:1066-74. [PMID: 25371207 DOI: 10.1074/jbc.m114.613091] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
Ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) is the key enzyme involved in photosynthetic carbon fixation, converting atmospheric CO2 to organic compounds. Form I Rubisco is a cylindrical complex composed of eight large (RbcL) subunits that are capped by four small subunits (RbcS) at the top and four at the bottom. Form I Rubiscos are phylogenetically divided into green- and red-type. Some red-type enzymes have catalytically superior properties. Thus, understanding their folding and assembly is of considerable biotechnological interest. Folding of the green-type RbcL subunits in cyanobacteria is mediated by the GroEL/ES chaperonin system, and assembly to holoenzyme requires specialized chaperones such as RbcX and RAF1. Here, we show that the red-type RbcL subunits in the proteobacterium Rhodobacter sphaeroides also fold with GroEL/ES. However, assembly proceeds in a chaperone-independent manner. We find that the C-terminal β-hairpin extension of red-type RbcS, which is absent in green-type RbcS, is critical for efficient assembly. The β-hairpins of four RbcS subunits form an eight-stranded β-barrel that protrudes into the central solvent channel of the RbcL core complex. The two β-barrels stabilize the complex through multiple interactions with the RbcL subunits. A chimeric green-type RbcS carrying the C-terminal β-hairpin renders the assembly of a cyanobacterial Rubisco independent of RbcX. Our results may facilitate the engineering of crop plants with improved growth properties expressing red-type Rubisco.
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Affiliation(s)
- Jidnyasa Joshi
- From the Department of Cellular Biochemistry, Max Planck Institute of Biochemistry, 82152 Martinsried, Germany
| | - Oliver Mueller-Cajar
- From the Department of Cellular Biochemistry, Max Planck Institute of Biochemistry, 82152 Martinsried, Germany
| | - Yi-Chin C Tsai
- From the Department of Cellular Biochemistry, Max Planck Institute of Biochemistry, 82152 Martinsried, Germany
| | - F Ulrich Hartl
- From the Department of Cellular Biochemistry, Max Planck Institute of Biochemistry, 82152 Martinsried, Germany
| | - Manajit Hayer-Hartl
- From the Department of Cellular Biochemistry, Max Planck Institute of Biochemistry, 82152 Martinsried, Germany
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Wang Y, Lin S, Song Q, Li K, Tao H, Huang J, Chen X, Que S, He H. Genome-wide identification of heat shock proteins (Hsps) and Hsp interactors in rice: Hsp70s as a case study. BMC Genomics 2014; 15:344. [PMID: 24884676 PMCID: PMC4035072 DOI: 10.1186/1471-2164-15-344] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2013] [Accepted: 04/28/2014] [Indexed: 12/22/2022] Open
Abstract
BACKGROUND Heat shock proteins (Hsps) perform a fundamental role in protecting plants against abiotic stresses. Although researchers have made great efforts on the functional analysis of individual family members, Hsps have not been fully characterized in rice (Oryza sativa L.) and little is known about their interactors. RESULTS In this study, we combined orthology-based approach with expression association data to screen rice Hsps for the expression patterns of which strongly correlated with that of heat responsive probe-sets. Twenty-seven Hsp candidates were identified, including 12 small Hsps, six Hsp70s, three Hsp60s, three Hsp90s, and three clpB/Hsp100s. Then, using a combination of interolog and expression profile-based methods, we inferred 430 interactors of Hsp70s in rice, and validated the interactions by co-localization and function-based methods. Subsequent analysis showed 13 interacting domains and 28 target motifs were over-represented in Hsp70s interactors. Twenty-four GO terms of biological processes and five GO terms of molecular functions were enriched in the positive interactors, whose expression levels were positively associated with Hsp70s. Hsp70s interaction network implied that Hsp70s were involved in macromolecular translocation, carbohydrate metabolism, innate immunity, photosystem II repair and regulation of kinase activities. CONCLUSIONS Twenty-seven Hsps in rice were identified and 430 interactors of Hsp70s were inferred and validated, then the interacting network of Hsp70s was induced and the function of Hsp70s was analyzed. Furthermore, two databases named Rice Heat Shock Proteins (RiceHsps) and Rice Gene Expression Profile (RGEP), and one online tool named Protein-Protein Interaction Predictor (PPIP), were constructed and could be accessed at http://bioinformatics.fafu.edu.cn/.
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Affiliation(s)
| | | | | | | | | | | | | | | | - Huaqin He
- College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou 350002, China.
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Jiang Q, Mei J, Gong XD, Xu JL, Zhang JH, Teng S, Lin DZ, Dong YJ. Importance of the rice TCD9 encoding α subunit of chaperonin protein 60 (Cpn60α) for the chloroplast development during the early leaf stage. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2014; 215-216:172-9. [PMID: 24388528 DOI: 10.1016/j.plantsci.2013.11.003] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/08/2013] [Revised: 11/03/2013] [Accepted: 11/06/2013] [Indexed: 05/05/2023]
Abstract
The chloroplast development governs plant growth and metabolism. This study characterized a novel rice thermo-sensitive chloroplast development 9 (tcd9) mutant, which exhibited the albino phenotype before the 3-leaf stage grown below 24 °C whereas displayed normal green at over 28 °C or even at 20 °C after 5-leaf stage. The obvious decrease in Chl levels, abnormal chloroplasts with few thylakoid lamella and abnormal thylakoids were observed for the albino mutant seedlings at low temperature, but the mutant was apparently normal green at high temperature, suggesting the thermo-sensitivity of albino phenotype. Genetic analysis showed that the albino phenotype was controlled by a single recessive nuclear gene (tcd9). The map-based cloning and molecular complementation tests revealed that the mutation of TCD9 encoding α subunit of Cpn60 protein (Cpn60α), localized in chloroplasts, was responsible for albino phenotype. In addition, TCD9 exhibited the high expression in all tested tissues, especially in young leaves. The transcriptional analysis indicated that all expression levels of the studied genes related to chloroplast development in tcd9 mutant were seriously affected in the albino seedlings at 20 °C, whereas some of them recovered into normal levels in green-seedlings at 32 °C. Our observations suggest that the nuclear-encoded Cpn60α protein TCD9 plays a crucial role in chloroplast development at early leaf stage of rice.
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Affiliation(s)
- Quan Jiang
- Development Center of Plant Germplasm Resources, College of Life and Environment Sciences, Shanghai Normal University, Shanghai 200234, China
| | - Jie Mei
- Development Center of Plant Germplasm Resources, College of Life and Environment Sciences, Shanghai Normal University, Shanghai 200234, China
| | - Xiao-Di Gong
- Development Center of Plant Germplasm Resources, College of Life and Environment Sciences, Shanghai Normal University, Shanghai 200234, China
| | - Jian-Long Xu
- The Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, 12 South Zhong-Guan Cun Street, Beijing 100081, China
| | - Jian-Hui Zhang
- Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200032, China
| | - Sheng Teng
- Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200032, China
| | - Dong-Zhi Lin
- Development Center of Plant Germplasm Resources, College of Life and Environment Sciences, Shanghai Normal University, Shanghai 200234, China.
| | - Yan-Jun Dong
- Development Center of Plant Germplasm Resources, College of Life and Environment Sciences, Shanghai Normal University, Shanghai 200234, China.
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37
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Vitlin Gruber A, Nisemblat S, Azem A, Weiss C. The complexity of chloroplast chaperonins. TRENDS IN PLANT SCIENCE 2013; 18:688-94. [PMID: 24035661 DOI: 10.1016/j.tplants.2013.08.001] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/20/2013] [Revised: 07/29/2013] [Accepted: 08/07/2013] [Indexed: 05/07/2023]
Abstract
Type I chaperonins are large oligomeric protein ensembles that are involved in the folding and assembly of other proteins. Chloroplast chaperonins and co-chaperonins exist in multiple copies of two distinct isoforms that can combine to form a range of labile oligomeric structures. This complex system increases the potential number of chaperonin substrates and possibilities for regulation. The incorporation of unique subunits into the oligomer can modify substrate specificity. Some subunits are upregulated in response to heat shock and some show organ-specific expression, whereas others possess additional functions that are unrelated to their role in protein folding. Accumulating evidence suggests that specific subunits have distinct roles in biogenesis of ribulose-1,5-bisphosphate carboxylase oxygenase (Rubisco).
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Affiliation(s)
- Anna Vitlin Gruber
- The George S. Wise Faculty of Life Sciences, Department of Biochemistry and Molecular Biology, Tel Aviv University, Ramat Aviv, Israel
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38
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Li YF, Wang Y, Tang Y, Kakani VG, Mahalingam R. Transcriptome analysis of heat stress response in switchgrass (Panicum virgatum L.). BMC PLANT BIOLOGY 2013; 13:153. [PMID: 24093800 PMCID: PMC3851271 DOI: 10.1186/1471-2229-13-153] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/07/2013] [Accepted: 10/03/2013] [Indexed: 05/19/2023]
Abstract
BACKGROUND Global warming predictions indicate that temperatures will increase by another 2-6°C by the end of this century. High temperature is a major abiotic stress limiting plant growth and productivity in many areas of the world. Switchgrass (Panicum virgatum L.) is a model herbaceous bioenergy crop, due to its rapid growth rate, reliable biomass yield, minimal requirements of water and nutrients, adaptability to grow on marginal lands and widespread distribution throughout North America. The effect of high temperature on switchgrass physiology, cell wall composition and biomass yields has been reported. However, there is void in the knowledge of the molecular responses to heat stress in switchgrass. RESULTS We conducted long-term heat stress treatment (38°/30°C, day/night, for 50 days) in the switchgrass cultivar Alamo. A significant decrease in the plant height and total biomass was evident in the heat stressed plants compared to controls. Total RNA from control and heat stress samples were used for transcriptome analysis with switchgrass Affymetrix genechips. Following normalization and pre-processing, 5365 probesets were identified as differentially expressed using a 2-fold cutoff. Of these, 2233 probesets (2000 switchgrass unigenes) were up-regulated, and 3132 probesets (2809 unigenes) were down-regulated. Differential expression of 42 randomly selected genes from this list was validated using RT-PCR. Rice orthologs were retrieved for 78.7% of the heat stress responsive switchgrass probesets. Gene ontology (GOs) enrichment analysis using AgriGO program showed that genes related to ATPase regulator, chaperone binding, and protein folding was significantly up-regulated. GOs associated with protein modification, transcription, phosphorus and nitrogen metabolic processes, were significantly down-regulated by heat stress. CONCLUSIONS Plausible connections were identified between the identified GOs, physiological responses and heat response phenotype observed in switchgrass plants. Comparative transcriptome analysis in response to heat stress among four monocots - switchgrass, rice, wheat and maize identified 16 common genes, most of which were associated with protein refolding processes. These core genes will be valuable biomarkers for identifying heat sensitive plant germplasm since they are responsive to both short duration as well as chronic heat stress treatments, and are also expressed in different plant growth stages and tissue types.
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Affiliation(s)
- Yong-Fang Li
- Department of Biochemistry and Molecular Biology, Oklahoma State University, Stillwater, OK 74078, USA
| | - Yixing Wang
- Department of Biochemistry and Molecular Biology, Oklahoma State University, Stillwater, OK 74078, USA
| | - Yuhong Tang
- Samuel Roberts Noble Foundation, Genomics Core Facility, Ardmore, OK 73401, USA
| | - Vijaya Gopal Kakani
- Department of Plant and Soil Sciences, Oklahoma State University, Stillwater, OK 74078, USA
| | - Ramamurthy Mahalingam
- Department of Biochemistry and Molecular Biology, Oklahoma State University, Stillwater, OK 74078, USA
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Zhang XF, Jiang T, Wu Z, Du SY, Yu YT, Jiang SC, Lu K, Feng XJ, Wang XF, Zhang DP. Cochaperonin CPN20 negatively regulates abscisic acid signaling in Arabidopsis. PLANT MOLECULAR BIOLOGY 2013; 83:205-18. [PMID: 23783410 PMCID: PMC3777161 DOI: 10.1007/s11103-013-0082-8] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/07/2013] [Accepted: 05/26/2013] [Indexed: 05/08/2023]
Abstract
Previous study showed that the magnesium-protoporphyrin IX chelatase H subunit (CHLH/ABAR) positively regulates abscisic acid (ABA) signaling. Here, we investigated the functions of a CHLH/ABAR interaction protein, the chloroplast co-chaperonin 20 (CPN20) in ABA signaling in Arabidopsis thaliana. We showed that down-expression of the CPN20 gene increases, but overexpression of the CPN20 gene reduces, ABA sensitivity in the major ABA responses including ABA-induced seed germination inhibition, postgermination growth arrest, promotion of stomatal closure and inhibition of stomatal opening. Genetic evidence supports that CPN20 functions downstream or at the same node of CHLH/ABAR, but upstream of the WRKY40 transcription factor. The other CPN20 interaction partners CPN10 and CPN60 are not involved in ABA signaling. Our findings show that CPN20 functions negatively in the ABAR-WRKY40 coupled ABA signaling independently of its co-chaperonin role, and provide a new insight into the role of co-chaperones in the regulation of plant responses to environmental cues.
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Affiliation(s)
- Xiao-Feng Zhang
- MOE Systems Biology and Bioinformatics Laboratory, School of Life Sciences, Tsinghua University, Beijing, 100084 China
| | - Tao Jiang
- MOE Systems Biology and Bioinformatics Laboratory, School of Life Sciences, Tsinghua University, Beijing, 100084 China
| | - Zhen Wu
- MOE Systems Biology and Bioinformatics Laboratory, School of Life Sciences, Tsinghua University, Beijing, 100084 China
| | - Shu-Yuan Du
- MOE Systems Biology and Bioinformatics Laboratory, School of Life Sciences, Tsinghua University, Beijing, 100084 China
| | - Yong-Tao Yu
- MOE Systems Biology and Bioinformatics Laboratory, School of Life Sciences, Tsinghua University, Beijing, 100084 China
| | - Shang-Chuan Jiang
- MOE Systems Biology and Bioinformatics Laboratory, School of Life Sciences, Tsinghua University, Beijing, 100084 China
| | - Kai Lu
- MOE Systems Biology and Bioinformatics Laboratory, School of Life Sciences, Tsinghua University, Beijing, 100084 China
| | - Xiu-Jing Feng
- MOE Systems Biology and Bioinformatics Laboratory, School of Life Sciences, Tsinghua University, Beijing, 100084 China
| | - Xiao-Fang Wang
- MOE Systems Biology and Bioinformatics Laboratory, School of Life Sciences, Tsinghua University, Beijing, 100084 China
| | - Da-Peng Zhang
- MOE Systems Biology and Bioinformatics Laboratory, School of Life Sciences, Tsinghua University, Beijing, 100084 China
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Shen-Miller J, Lindner P, Xie Y, Villa S, Wooding K, Clarke SG, Loo RRO, Loo JA. Thermal-stable proteins of fruit of long-living Sacred Lotus Nelumbo nucifera Gaertn var. China Antique. TROPICAL PLANT BIOLOGY 2013; 6:10.1007/s12042-013-9124-2. [PMID: 24363819 PMCID: PMC3869599 DOI: 10.1007/s12042-013-9124-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
Single-seeded fruit of the sacred lotus Nelumbo nucifera Gaertn var. China Antique from NE China have viability as long as ~1300 years determined by direct radiocarbon-dating, having a germination rate of 84%. The pericarp, a fruit tissue that encloses the single seeds of Nelumbo, is considered one of the major factors that contribute to fruit longevity. Proteins that are heat stable and have protective function may be equally important to seed viability. We show proteins of Nelumbo fruit that are able to withstand heating, 31% of which remained soluble in the 110°C-treated embryo-axis of a 549-yr-old fruit and 76% retained fluidity in its cotyledons. Genome of Nelumbo is published. The amino-acid sequences of 11 "thermal proteins" (soluble at 100°C) of modern Nelumbo embryo-axes and cotyledons, identified by mass spectrometry, Western blot and bioassay, are assembled and aligned with those of an archaeal-hyperthermophile Methancaldococcus jannaschii (Mj; an anaerobic methanogen having a growth optimum of 85°C) and with five mesophile angiosperms. These thermal proteins have roles in protection and repair under stress. More than half of the Nelumbo thermal proteins (55%) are present in the archaean Mj, indicating their long-term durability and history. One Nelumbo protein-repair enzyme exhibits activity at 100°C, having a higher heat-tolerance than that of Arabidopsis. A list of 30 sequenced but unassembled thermal proteins of Nelumbo is supplemented.
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Affiliation(s)
- J Shen-Miller
- IGPP Center for the Study of Evolution and Origin of Life, Department of Ecology and Evolutionary Biology, University of California, Los Angeles, Geology Building, Room 5676, 595 Charles E. Young Drive East, Los Angeles, CA 90095-1567, USA, Telephone: (310) 825-2891, ,
| | - Petra Lindner
- Lehrstuhl Mikrobiologie Regensburg University Universitat Str. 31 93053 Regensburg, Germany
| | - Yongming Xie
- Department of Chemistry and Biochemistry University of California, Los Angeles 402 Boyer Hall, Hilgard Avenue Los Angeles, CA 90095-1569, USA
| | - Sarah Villa
- Department of Chemistry and Biochemistry University of California, Los Angeles 640 Boyer Hall, Hilgard Avenue Los Angeles, CA 90095-1570, USA
| | - Kerry Wooding
- Department of Chemistry and Biochemistry University of California, Los Angeles 402 Boyer Hall, Hilgard Avenue Los Angeles, CA 90095-1569, USA
| | - Steven G Clarke
- Department of Chemistry and Biochemistry University of California, Los Angeles 640 Boyer Hall, Hilgard Avenue Los Angeles, CA 90095-1570, USA
| | - Rachel R O Loo
- Department of Chemistry and Biochemistry University of California, Los Angeles 402 Boyer Hall, Hilgard Avenue Los Angeles, CA 90095-1569, USA
| | - Joseph A Loo
- Department of Chemistry and Biochemistry University of California, Los Angeles 402 Boyer Hall, Hilgard Avenue Los Angeles, CA 90095-1569, USA
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Kim SR, Yang JI, An G. OsCpn60α1, encoding the plastid chaperonin 60α subunit, is essential for folding of rbcL. Mol Cells 2013; 35:402-9. [PMID: 23620301 PMCID: PMC3887859 DOI: 10.1007/s10059-013-2337-2] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2012] [Revised: 03/12/2013] [Accepted: 03/12/2013] [Indexed: 01/06/2023] Open
Abstract
Chaperonins are involved in protein-folding. The rice genome encodes six plastid chaperonin subunits (Cpn60) - three α and three β. Our study showed that they were differentially expressed during normal plant development. Moreover, five were induced by heat stress (42°C) but not by cold (10°C). The oscpn60α1 mutant had a pale-green phenotype at the seedling stage and development ceased after the fourth leaf appeared. Transiently expressed OsCpn60α1:GFP fusion protein was localized to the chloroplast stroma. Immuno-blot analysis indicated that the level of Rubisco large subunit (rbcL) was severely reduced in the mutant while levels were unchanged for some imported proteins, e.g., stromal heat shock protein 70 (Hsp70) and chlorophyll a/b binding protein 1 (Lhcb1). This demonstrated that OsCpn60α1 is required for the folding of rbcL and that failure of that process is seedling-lethal.
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Affiliation(s)
- Sung-Ryul Kim
- Crop Biotech Institute and Department of Genetic Engineering, Kyung Hee University, Yongin 446-701,
Korea
| | - Jung-Il Yang
- Crop Biotech Institute and Department of Genetic Engineering, Kyung Hee University, Yongin 446-701,
Korea
| | - Gynheung An
- Crop Biotech Institute and Department of Genetic Engineering, Kyung Hee University, Yongin 446-701,
Korea
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Henderson B, Fares MA, Lund PA. Chaperonin 60: a paradoxical, evolutionarily conserved protein family with multiple moonlighting functions. Biol Rev Camb Philos Soc 2013; 88:955-87. [DOI: 10.1111/brv.12037] [Citation(s) in RCA: 91] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2012] [Revised: 02/20/2013] [Accepted: 03/04/2013] [Indexed: 02/07/2023]
Affiliation(s)
- Brian Henderson
- Department of Microbial Diseases, UCL-Eastman Dental Institute; University College London; London WC1X 8LD U.K
| | - Mario A. Fares
- Department of Genetics; University of Dublin, Trinity College Dublin; Dublin 2 Ireland
- Department of Abiotic Stress; Instituto de Biologia Molecular y Celular de Plantas, Consejo Superior de Investigaciones Cientificas (CSIC-UPV); Valencia 46022 Spain
| | - Peter A. Lund
- School of Biosciences; University of Birmingham; Birmingham B15 2TT U.K
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Arc E, Chibani K, Grappin P, Jullien M, Godin B, Cueff G, Valot B, Balliau T, Job D, Rajjou L. Cold stratification and exogenous nitrates entail similar functional proteome adjustments during Arabidopsis seed dormancy release. J Proteome Res 2012; 11:5418-32. [PMID: 22985405 DOI: 10.1021/pr3006815] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Despite having very similar initial pools of stored mRNAs and proteins in the dry state, mature Arabidopsis seeds can either proceed toward radicle protrusion or stay in a dormant state upon imbibition. Dormancy breaking, a prerequisite to germination completion, can be induced by different treatments though the underlying mechanisms remain elusive. Thus, we investigated the consequence of such treatments on the seed proteome. Two unrelated dormancy-releasing treatments were applied to dormant seeds, namely, cold stratification and exogenous nitrates, in combination with differential proteomic tools to highlight the specificities of the imbibed dormant state. The results reveal that both treatments lead to highly similar proteome adjustments. In the imbibed dormant state, enzymes involved in reserve mobilization are less accumulated and it appears that several energetically costly processes associated to seed germination and preparation for subsequent seedling establishment are repressed. Our data suggest that dormancy maintenance is associated to an abscisic-acid-dependent recapitulation of the late maturation program resulting in a higher potential to cope with environmental stresses. The comparison of the present results with previously published -omic data sets reinforces and extends the assumption that post-transcriptional, translational, and post-translational regulations are determinant for seed germination.
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Affiliation(s)
- Erwann Arc
- INRA, Jean-Pierre Bourgin Institute (IJPB, UMR1318 INRA-AgroParisTech), Laboratory of Excellence Saclay Plant Sciences, RD10, F-78002 Versailles Cedex, France.
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44
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Kurepa J, Wang S, Smalle J. The role of 26S proteasome-dependent proteolysis in the formation and restructuring of microtubule networks. PLANT SIGNALING & BEHAVIOR 2012; 7:1289-1295. [PMID: 22902696 PMCID: PMC3493416 DOI: 10.4161/psb.21543] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
In this review, we summarize the evidence pointing at the important role of 26S proteasome-dependent proteolysis in the regulation of microtubule synthesis and microtubule dynamics. Because most of the advances in this relatively unexplored research field originate from yeast and animal studies, we have considered those studies that describe the role of proteolysis in processes that are evolutionarily conserved and known to exist in plants. In addition, we place particular emphasis on the proteasome-dependent degradation of plant-specific microtubule-associated protein SPIRAL1 and its function in MT rearrangements associated with salt stress.
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45
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Feiz L, Williams-Carrier R, Wostrikoff K, Belcher S, Barkan A, Stern DB. Ribulose-1,5-bis-phosphate carboxylase/oxygenase accumulation factor1 is required for holoenzyme assembly in maize. THE PLANT CELL 2012; 24:3435-46. [PMID: 22942379 PMCID: PMC3462642 DOI: 10.1105/tpc.112.102012] [Citation(s) in RCA: 82] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/24/2012] [Revised: 07/10/2012] [Accepted: 08/08/2012] [Indexed: 05/03/2023]
Abstract
Most life is ultimately sustained by photosynthesis and its rate-limiting carbon fixing enzyme, ribulose-1,5-bis-phosphate carboxylase/oxygenase (Rubisco). Although the structurally comparable cyanobacterial Rubisco is amenable to in vitro assembly, the higher plant enzyme has been refractory to such manipulation due to poor understanding of its assembly pathway. Here, we report the identification of a chloroplast protein required for Rubisco accumulation in maize (Zea mays), RUBISCO ACCUMULATION FACTOR1 (RAF1), which lacks any characterized functional domains. Maize lines lacking RAF1 due to Mutator transposon insertions are Rubisco deficient and seedling lethal. Analysis of transcripts and proteins showed that Rubisco large subunit synthesis in raf1 plants is not compromised; however, newly synthesized Rubisco large subunit appears in a high molecular weight form whose accumulation requires a specific chaperonin 60 isoform. Gel filtration analysis and blue native gels showed that endogenous and recombinant RAF1 are trimeric; however, following in vivo cross-linking, RAF1 copurifies with Rubisco large subunit, suggesting that they interact weakly or transiently. RAF1 is predominantly expressed in bundle sheath chloroplasts, consistent with a Rubisco accumulation function. Our results support the hypothesis that RAF1 acts during Rubisco assembly by releasing and/or sequestering the large subunit from chaperonins early in the assembly process.
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Affiliation(s)
- Leila Feiz
- Boyce Thompson Institute for Plant Research, Cornell University, Ithaca, New York 14853
| | | | - Katia Wostrikoff
- Boyce Thompson Institute for Plant Research, Cornell University, Ithaca, New York 14853
| | - Susan Belcher
- Institute of Molecular Biology, University of Oregon, Eugene, Oregon 97403
| | - Alice Barkan
- Institute of Molecular Biology, University of Oregon, Eugene, Oregon 97403
| | - David B. Stern
- Boyce Thompson Institute for Plant Research, Cornell University, Ithaca, New York 14853
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Tsai YCC, Mueller-Cajar O, Saschenbrecker S, Hartl FU, Hayer-Hartl M. Chaperonin cofactors, Cpn10 and Cpn20, of green algae and plants function as hetero-oligomeric ring complexes. J Biol Chem 2012; 287:20471-81. [PMID: 22518837 DOI: 10.1074/jbc.m112.365411] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
The chloroplast chaperonin system of plants and green algae is a curiosity as both the chaperonin cage and its lid are encoded by multiple genes, in contrast to the single genes encoding the two components of the bacterial and mitochondrial systems. In the green alga Chlamydomonas reinhardtii (Cr), three genes encode chaperonin cofactors, with cpn10 encoding a single ∼10-kDa domain and cpn20 and cpn23 encoding tandem cpn10 domains. Here, we characterized the functional interaction of these proteins with the Escherichia coli chaperonin, GroEL, which normally cooperates with GroES, a heptamer of ∼10-kDa subunits. The C. reinhardtii cofactor proteins alone were all unable to assist GroEL-mediated refolding of bacterial ribulose-bisphosphate carboxylase/oxygenase but gained this ability when CrCpn20 and/or CrCpn23 was combined with CrCpn10. Native mass spectrometry indicated the formation of hetero-oligomeric species, consisting of seven ∼10-kDa domains. The cofactor "heptamers" interacted with GroEL and encapsulated substrate protein in a nucleotide-dependent manner. Different hetero-oligomer arrangements, generated by constructing cofactor concatamers, indicated a preferential heptamer configuration for the functional CrCpn10-CrCpn23 complex. Formation of heptamer Cpn10/Cpn20 hetero-oligomers was also observed with the Arabidopsis thaliana (At) cofactors, which functioned with the chloroplast chaperonin, AtCpn60α(7)β(7). It appears that hetero-oligomer formation occurs more generally for chloroplast chaperonin cofactors, perhaps adapting the chaperonin system for the folding of specific client proteins.
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Affiliation(s)
- Yi-Chin C Tsai
- Department of Cellular Biochemistry, Max Planck Institute of Biochemistry, 82152 Martinsried, Germany
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Vitlin A, Weiss C, Demishtein-Zohary K, Rasouly A, Levin D, Pisanty-Farchi O, Breiman A, Azem A. Chloroplast β chaperonins from A. thaliana function with endogenous cpn10 homologs in vitro. PLANT MOLECULAR BIOLOGY 2011; 77:105-15. [PMID: 21633907 DOI: 10.1007/s11103-011-9797-6] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/20/2011] [Accepted: 05/18/2011] [Indexed: 05/15/2023]
Abstract
The involvement of type I chaperonins in bacterial and organellar protein folding has been well-documented. In E. coli and mitochondria, these ubiquitous and highly conserved proteins form chaperonin oligomers of identical 60 kDa subunits (cpn60), while in chloroplasts, two distinct cpn60 α and β subunit types co-exist together. The primary sequence of α and β subunits is ~50% identical, similar to their respective homologies to the bacterial GroEL. Moreover, the A. thaliana genome contains two α and four β genes. The functional significance of this variability in plant chaperonin proteins has not yet been elucidated. In order to gain insight into the functional variety of the chloroplast chaperonin family members, we reconstituted β homo-oligomers from A. thaliana following their expression in bacteria and subjected them to a structure-function analysis. Our results show for the first time, that A. thaliana β homo-oligomers can function in vitro with authentic chloroplast co-chaperonins (ch-cpn10 and ch-cpn20). We also show that oligomers made up of different β subunit types have unique properties and different preferences for co-chaperonin partners. We propose that chloroplasts may contain active β homo-oligomers in addition to hetero-oligomers, possibly reflecting a variety of cellular roles.
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Affiliation(s)
- Anna Vitlin
- Department of Biochemistry and Molecular Biology, Tel Aviv University, 69978 Tel Aviv, Israel
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Poulter NS, Bosch M, Franklin-Tong VE. Proteins implicated in mediating self-incompatibility-induced alterations to the actin cytoskeleton of Papaver pollen. ANNALS OF BOTANY 2011; 108:659-75. [PMID: 21320881 PMCID: PMC3170148 DOI: 10.1093/aob/mcr022] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/04/2010] [Accepted: 01/04/2011] [Indexed: 05/20/2023]
Abstract
BACKGROUND AND AIMS Sexual reproduction in angiosperms involves a network of signalling and interactions between pollen and pistil. To promote out-breeding, an additional layer of interactions, involving self-incompatibility (SI), is used to prevent self-fertilization. SI is generally controlled by the S-locus, and comprises allelic pollen and pistil S-determinants. This provides the basis of recognition, and consequent rejection, of incompatible pollen. In Papaver rhoeas, SI involves interaction of pistil PrsS and pollen PrpS, triggering a Ca(2+)-dependent signalling network. This results in rapid and distinctive alterations to both the actin and microtubule cytoskeleton being triggered in 'self' pollen. Some of these alterations are implicated in mediating programmed cell death, involving activation of several caspase-like proteases. SCOPE Here we review and discuss our current understanding of the cytoskeletal alterations induced in incompatible pollen during SI and their relationship with programmed cell death. We focus on data relating to the formation of F-actin punctate foci, which have, to date, not been well characterized. The identification of two actin-binding proteins that interact with these structures are reviewed. Using an approach that enriched for F-actin from SI-induced pollen tubes using affinity purification followed by mass spectrometry, further proteins were identified as putative interactors with the F-actin foci in an SI situation. KEY RESULTS Previously two important actin-binding proteins, CAP and ADF, had been identified whose localization altered with SI, both showing co-localization with the F-actin punctate foci based on immunolocalization studies. Further analysis has identified differences between proteins associated with F-actin from SI-induced pollen samples and those associated with F-actin in untreated pollen. This provides candidate proteins implicated in either the formation or stabilization of the punctate actin structures formed during SI. CONCLUSIONS This review brings together for the first time, our current understanding of proteins and events involved in SI-induced signalling to the actin cytoskeleton in incompatible Papaver pollen.
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Fernandez-Calvino L, Faulkner C, Walshaw J, Saalbach G, Bayer E, Benitez-Alfonso Y, Maule A. Arabidopsis plasmodesmal proteome. PLoS One 2011; 6:e18880. [PMID: 21533090 PMCID: PMC3080382 DOI: 10.1371/journal.pone.0018880] [Citation(s) in RCA: 194] [Impact Index Per Article: 14.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2010] [Accepted: 03/11/2011] [Indexed: 11/26/2022] Open
Abstract
The multicellular nature of plants requires that cells should communicate in order to coordinate essential functions. This is achieved in part by molecular flux through pores in the cell wall, called plasmodesmata. We describe the proteomic analysis of plasmodesmata purified from the walls of Arabidopsis suspension cells. Isolated plasmodesmata were seen as membrane-rich structures largely devoid of immunoreactive markers for the plasma membrane, endoplasmic reticulum and cytoplasmic components. Using nano-liquid chromatography and an Orbitrap ion-trap tandem mass spectrometer, 1341 proteins were identified. We refer to this list as the plasmodesmata- or PD-proteome. Relative to other cell wall proteomes, the PD-proteome is depleted in wall proteins and enriched for membrane proteins, but still has a significant number (35%) of putative cytoplasmic contaminants, probably reflecting the sensitivity of the proteomic detection system. To validate the PD-proteome we searched for known plasmodesmal proteins and used molecular and cell biological techniques to identify novel putative plasmodesmal proteins from a small subset of candidates. The PD-proteome contained known plasmodesmal proteins and some inferred plasmodesmal proteins, based upon sequence or functional homology with examples identified in different plant systems. Many of these had a membrane association reflecting the membranous nature of isolated structures. Exploiting this connection we analysed a sample of the abundant receptor-like class of membrane proteins and a small random selection of other membrane proteins for their ability to target plasmodesmata as fluorescently-tagged fusion proteins. From 15 candidates we identified three receptor-like kinases, a tetraspanin and a protein of unknown function as novel potential plasmodesmal proteins. Together with published work, these data suggest that the membranous elements in plasmodesmata may be rich in receptor-like functions, and they validate the content of the PD-proteome as a valuable resource for the further uncovering of the structure and function of plasmodesmata as key components in cell-to-cell communication in plants.
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Affiliation(s)
| | - Christine Faulkner
- John Innes Centre, Norwich Research Park, Colney, Norwich, United Kingdom
| | - John Walshaw
- John Innes Centre, Norwich Research Park, Colney, Norwich, United Kingdom
| | - Gerhard Saalbach
- John Innes Centre, Norwich Research Park, Colney, Norwich, United Kingdom
| | - Emmanuelle Bayer
- CNRS - Laboratoire de Biogenèse Membranaire, UMR5200, Bordeaux, France
| | | | - Andrew Maule
- John Innes Centre, Norwich Research Park, Colney, Norwich, United Kingdom
- * E-mail:
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50
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A chaperonin subunit with unique structures is essential for folding of a specific substrate. PLoS Biol 2011; 9:e1001040. [PMID: 21483722 PMCID: PMC3071376 DOI: 10.1371/journal.pbio.1001040] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2010] [Accepted: 02/23/2011] [Indexed: 01/01/2023] Open
Abstract
Type I chaperonins are large, double-ring complexes present in bacteria (GroEL),
mitochondria (Hsp60), and chloroplasts (Cpn60), which are involved in mediating
the folding of newly synthesized, translocated, or stress-denatured proteins. In
Escherichia coli, GroEL comprises 14 identical subunits and
has been exquisitely optimized to fold its broad range of substrates. However,
multiple Cpn60 subunits with different expression profiles have evolved in
chloroplasts. Here, we show that, in Arabidopsis thaliana, the
minor subunit Cpn60β4 forms a heterooligomeric Cpn60 complex with
Cpn60α1 and Cpn60β1–β3 and is specifically required for the
folding of NdhH, a subunit of the chloroplast NADH dehydrogenase-like complex
(NDH). Other Cpn60β subunits cannot complement the function of Cpn60β4.
Furthermore, the unique C-terminus of Cpn60β4 is required for the full
activity of the unique Cpn60 complex containing Cpn60β4 for folding of NdhH.
Our findings suggest that this unusual kind of subunit enables the Cpn60 complex
to assist the folding of some particular substrates, whereas other dominant
Cpn60 subunits maintain a housekeeping chaperonin function by facilitating the
folding of other obligate substrates. Chaperonins assist the folding of some nascent and denatured proteins to their
native, functional forms. Each chaperonin consists of a pair of protein
complexes resembling two stacked toroids; folding occurs inside the toroid
cavity. Chaperonins are ubiquitous in both bacteria and more complex nucleated
cells, as well as in the intracellular organelles that have evolved from
bacteria by endosymbiosis: mitochondria and, in plants, chloroplasts. They are
indispensable for cellular function. Many different chaperonin subunits have
evolved in various species of bacteria as well as in most mitochondria and
chloroplasts. The physiological and functional relevance of these multiple
chaperonin subunits is poorly understood, however. In this study, we have
characterized the minor chaperonin subunit Cpn60β4 from
Arabidopsis chloroplasts, which differs in structure from
other chloroplast chaperonins. When the Cpn60β4 gene is
defective, the plants fail to accumulate one protein complex in particular: the
chloroplast NADH dehydrogenase-like complex (NDH). We discovered that
Cpn60β4 forms a complex with other Cpn60 α and β
subunits and that this complex is essential for the folding of the NDH subunit
NdhH. Cpn60β4 has a unique protein “tail” that is required for
the efficient folding of NdhH. Our findings suggest that Cpn60β4 has evolved
with distinctive structural features that facilitate the folding of one specific
substrate and that this strategy is used by plants to satisfy their conflicting
requirements for chaperonins with both specialized and general functions.
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