1
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Mu B, Nair AM, Zhao R. Plastid HSP90C C-terminal extension region plays a regulatory role in chaperone activity and client binding. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2024. [PMID: 38969341 DOI: 10.1111/tpj.16917] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/07/2024] [Revised: 06/11/2024] [Accepted: 06/22/2024] [Indexed: 07/07/2024]
Abstract
HSP90Cs are essential molecular chaperones localized in the plastid stroma that maintain protein homeostasis and assist the import and thylakoid transport of chloroplast proteins. While HSP90C contains all conserved domains as an HSP90 family protein, it also possesses a unique feature in its variable C-terminal extension (CTE) region. This study elucidated the specific function of this HSP90C CTE region. Our phylogenetic analyses revealed that this intrinsically disordered region contains a highly conserved DPW motif in the green lineages. With biochemical assays, we showed that the CTE is required for the chaperone to effectively interact with client proteins PsbO1 and LHCB2 to regulate ATP-independent chaperone activity and to effectuate its ATP hydrolysis. The CTE truncation mutants could support plant growth and development reminiscing the wild type under normal conditions except for a minor phenotype in cotyledon when expressed at a level comparable to wild type. However, higher HSP90C expression was observed to correlate with a stronger response to specific photosystem II inhibitor DCMU, and CTE truncations dampened the response. Additionally, when treated with lincomycin to inhibit chloroplast protein translation, CTE truncation mutants showed a delayed response to PsbO1 expression repression, suggesting its role in chloroplast retrograde signaling. Our study therefore provides insights into the mechanism of HSP90C in client protein binding and the regulation of green chloroplast maturation and function, especially under stress conditions.
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Affiliation(s)
- Bona Mu
- Department of Biological Sciences, University of Toronto Scarborough, Toronto, Canada
- Department of Cell and Systems Biology, University of Toronto, Toronto, Canada
| | - Adheip Monikantan Nair
- Department of Biological Sciences, University of Toronto Scarborough, Toronto, Canada
- Department of Cell and Systems Biology, University of Toronto, Toronto, Canada
| | - Rongmin Zhao
- Department of Biological Sciences, University of Toronto Scarborough, Toronto, Canada
- Department of Cell and Systems Biology, University of Toronto, Toronto, Canada
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2
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Noureddine J, Mu B, Hamidzada H, Mok WL, Bonea D, Nambara E, Zhao R. Knockout of endoplasmic reticulum-localized molecular chaperone HSP90.7 impairs seedling development and cellular auxin homeostasis in Arabidopsis. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2024; 119:218-236. [PMID: 38565312 DOI: 10.1111/tpj.16754] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/24/2023] [Revised: 03/05/2024] [Accepted: 03/19/2024] [Indexed: 04/04/2024]
Abstract
The Arabidopsis endoplasmic reticulum-localized heat shock protein HSP90.7 modulates tissue differentiation and stress responses; however, complete knockout lines have not been previously reported. In this study, we identified and analyzed a mutant allele, hsp90.7-1, which was unable to accumulate the HSP90.7 full-length protein and showed seedling lethality. Microscopic analyses revealed its essential role in male and female fertility, trichomes and root hair development, proper chloroplast function, and apical meristem maintenance and differentiation. Comparative transcriptome and proteome analyses also revealed the role of the protein in a multitude of cellular processes. Particularly, the auxin-responsive pathway was specifically downregulated in the hsp90.7-1 mutant seedlings. We measured a much-reduced auxin content in both root and shoot tissues. Through comprehensive histological and molecular analyses, we confirmed PIN1 and PIN5 accumulations were dependent on the HSP90 function, and the TAA-YUCCA primary auxin biosynthesis pathway was also downregulated in the mutant seedlings. This study therefore not only fulfilled a gap in understanding the essential role of HSP90 paralogs in eukaryotes but also provided a mechanistic insight on the ER-localized chaperone in regulating plant growth and development via modulating cellular auxin homeostasis.
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Affiliation(s)
- Jenan Noureddine
- Department of Biological Sciences, University of Toronto Scarborough, Toronto, Ontario, Canada
- Cell & Systems Biology, University of Toronto, Toronto, Ontario, Canada
| | - Bona Mu
- Department of Biological Sciences, University of Toronto Scarborough, Toronto, Ontario, Canada
- Cell & Systems Biology, University of Toronto, Toronto, Ontario, Canada
| | - Homaira Hamidzada
- Department of Biological Sciences, University of Toronto Scarborough, Toronto, Ontario, Canada
| | - Wai Lam Mok
- Department of Biological Sciences, University of Toronto Scarborough, Toronto, Ontario, Canada
| | - Diana Bonea
- Department of Biological Sciences, University of Toronto Scarborough, Toronto, Ontario, Canada
- Cell & Systems Biology, University of Toronto, Toronto, Ontario, Canada
| | - Eiji Nambara
- Cell & Systems Biology, University of Toronto, Toronto, Ontario, Canada
| | - Rongmin Zhao
- Department of Biological Sciences, University of Toronto Scarborough, Toronto, Ontario, Canada
- Cell & Systems Biology, University of Toronto, Toronto, Ontario, Canada
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3
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Lamelas L, López-Hidalgo C, Valledor L, Meijón M, Cañal MJ. Like mother like son: Transgenerational memory and cross-tolerance from drought to heat stress are identified in chloroplast proteome and seed provisioning in Pinus radiata. PLANT, CELL & ENVIRONMENT 2024; 47:1640-1655. [PMID: 38282466 DOI: 10.1111/pce.14836] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/18/2023] [Revised: 01/09/2024] [Accepted: 01/13/2024] [Indexed: 01/30/2024]
Abstract
How different stressors impact plant health and memory when they are imposed in different generations in wild ecosystems is still scarce. Here, we address how different environments shape heritable memory for the next generation in seeds and seedlings of Pinus radiata, a long-lived species with economic interest. The performance of the seedlings belonging to two wild clonal subpopulations (optimal fertirrigation vs. slightly stressful conditions) was tested under heat stress through physiological profiling and comparative time-series chloroplast proteomics. In addition, we explored the seeds conducting a physiological characterization and targeted transcriptomic profiling in both subpopulations. Our results showed differential responses between them, evidencing a cross-stress transgenerational memory. Seedlings belonging to the stressed subpopulation retained key proteins related to Photosystem II, chloroplast-to-nucleus signalling and osmoprotection which helped to overcome the applied heat stress. The seeds also showed a differential gene expression profile for targeted genes and microRNAs, as well as an increased content of starch and secondary metabolites, molecules which showed potential interest as biomarkers for early selection of primed plants. Thus, these finds not only delve into transgenerational cross-stress memory in trees, but also provide a new biotechnological tool for forest design.
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Affiliation(s)
- Laura Lamelas
- Plant Physiology, Department of Organisms and Systems Biology, Biotechnology Institute of Asturias, University of Oviedo, Oviedo, Asturias, Spain
| | - Cristina López-Hidalgo
- Plant Physiology, Department of Organisms and Systems Biology, Biotechnology Institute of Asturias, University of Oviedo, Oviedo, Asturias, Spain
| | - Luis Valledor
- Plant Physiology, Department of Organisms and Systems Biology, Biotechnology Institute of Asturias, University of Oviedo, Oviedo, Asturias, Spain
| | - Mónica Meijón
- Plant Physiology, Department of Organisms and Systems Biology, Biotechnology Institute of Asturias, University of Oviedo, Oviedo, Asturias, Spain
| | - María Jesús Cañal
- Plant Physiology, Department of Organisms and Systems Biology, Biotechnology Institute of Asturias, University of Oviedo, Oviedo, Asturias, Spain
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4
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Nair AM, Jiang T, Mu B, Zhao R. Plastid Molecular Chaperone HSP90C Interacts with the SecA1 Subunit of Sec Translocase for Thylakoid Protein Transport. PLANTS (BASEL, SWITZERLAND) 2024; 13:1265. [PMID: 38732479 PMCID: PMC11085213 DOI: 10.3390/plants13091265] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/21/2024] [Revised: 04/24/2024] [Accepted: 04/29/2024] [Indexed: 05/13/2024]
Abstract
The plastid stroma-localized chaperone HSP90C plays a crucial role in maintaining optimal proteostasis within chloroplasts and participates in protein translocation processes. While existing studies have revealed HSP90C's direct interaction with the Sec translocase-dependent client pre-protein PsbO1 and the SecY1 subunit of the thylakoid membrane-bound Sec1 translocase channel system, its direct involvement with the extrinsic homodimeric Sec translocase subunit, SecA1, remains elusive. Employing bimolecular fluorescence complementation (BiFC) assay and other in vitro analyses, we unraveled potential interactions between HSP90C and SecA1. Our investigation revealed dynamic interactions between HSP90C and SecA1 at the thylakoid membrane and stroma. The thylakoid membrane localization of this interaction was contingent upon active HSP90C ATPase activity, whereas their stromal interaction was associated with active SecA1 ATPase activity. Furthermore, we observed a direct interaction between these two proteins by analyzing their ATP hydrolysis activities, and their interaction likely impacts their respective functional cycles. Additionally, using PsbO1, a model Sec translocase client pre-protein, we studied the intricacies of HSP90C's possible involvement in pre-protein translocation via the Sec1 system in chloroplasts. The results suggest a complex nature of the HSP90C-SecA1 interaction, possibly mediated by the Sec client protein. Our studies shed light on the nuanced aspects of HSP90C's engagement in orchestrating pre-protein translocation, and we propose a potential collaborative role of HSP90C with SecA1 in actively facilitating pre-protein transport across the thylakoid membrane.
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Affiliation(s)
| | | | | | - Rongmin Zhao
- Department of Biological Sciences, University of Toronto Scarborough, Toronto, ON M1C 1A4, Canada; Department of Cell & Systems Biology, University of Toronto, Toronto, ON M5S 3B2, Canada; (A.M.N.); (T.J.); (B.M.)
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5
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Shao Z, Bai Y, Huq E, Qiao H. LHP1 and INO80 cooperate with ethylene signaling for warm ambient temperature response by activating specific bivalent genes. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.03.01.583049. [PMID: 38496578 PMCID: PMC10942398 DOI: 10.1101/2024.03.01.583049] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/19/2024]
Abstract
Ethylene signaling has been indicated as a potential positive regulator of plant warm ambient temperature response but its underlying molecular mechanisms are largely unknown. Here, we show that LHP1 and INO80 cooperate with ethylene signaling for warm ambient temperature response by activating specific bivalent genes. We found that the presence of warm ambient temperature activates ethylene signaling through EIN2 and EIN3, leading to an interaction between LHP1 and accumulated EIN2-C to co-regulate a subset of LHP1-bound genes marked by H3K27me3 and H3K4me3 bivalency. Furthermore, we demonstrate that INO80 is recruited to bivalent genes by interacting with EIN2-C and EIN3, promoting H3K4me3 enrichment and facilitating transcriptional activation in response to warm ambient temperature. Together, our findings illustrate a novel mechanism wherein ethylene signaling orchestrates LHP1 and INO80 to regulate warm ambient temperature response through activating specific bivalent genes in Arabidopsis.
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Chang CY, Chen LJ, Li HM. Chloroplast import motor subunits FtsHi1 and FtsHi2 are located on opposite sides of the inner envelope membrane. Proc Natl Acad Sci U S A 2023; 120:e2307747120. [PMID: 37669373 PMCID: PMC10500165 DOI: 10.1073/pnas.2307747120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2023] [Accepted: 08/07/2023] [Indexed: 09/07/2023] Open
Abstract
Protein import into chloroplasts is powered by ATP hydrolysis in the stroma. Establishing the identity and functional mechanism of the stromal ATPase motor that drives import is critical for understanding chloroplast biogenesis. Recently, a complex consisting of Ycf2, FtsHi1, FtsHi2, FtsHi4, FtsHi5, FtsH12, and malate dehydrogenase was shown to be important for chloroplast protein import, and it has been proposed to act as the motor driving protein translocation across the chloroplast envelope into the stroma. To gain further mechanistic understanding of how the motor functions, we performed membrane association and topology analyses on two of its subunits, FtsHi1 and FtsHi2. We isolated cDNA clones encoding FtsHi1 and FtsHi2 preproteins to perform in vitro import experiments in order to determine the exact size of each mature protein. We also generated antibodies against the C-termini of the proteins, i.e., where their ATPase domains reside. Protease treatments and alkaline and high-salt extractions of chloroplasts with imported and endogenous proteins revealed that FtsHi1 is an integral membrane protein with its C-terminal portion located in the intermembrane space of the envelope, not the stroma, whereas FtsHi2 is a soluble protein in the stroma. We further complemented an FtsHi1-knockout mutant with a C-terminally tagged FtsHi1 and obtained identical results for topological analyses. Our data indicate that the model of a single membrane-anchored pulling motor at the stromal side of the inner membrane needs to be revised and suggest that the Ycf2-FtsHi complex may have additional functions.
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Affiliation(s)
- Chia-Yun Chang
- Institute of Molecular Biology, Academia Sinica, Taipei11529, Taiwan
| | - Lih-Jen Chen
- Institute of Molecular Biology, Academia Sinica, Taipei11529, Taiwan
| | - Hsou-min Li
- Institute of Molecular Biology, Academia Sinica, Taipei11529, Taiwan
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7
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Valencia-Lozano E, Herrera-Isidrón L, Flores-López JA, Recoder-Meléndez OS, Uribe-López B, Barraza A, Cabrera-Ponce JL. Exploring the Potential Role of Ribosomal Proteins to Enhance Potato Resilience in the Face of Changing Climatic Conditions. Genes (Basel) 2023; 14:1463. [PMID: 37510367 PMCID: PMC10379993 DOI: 10.3390/genes14071463] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2023] [Revised: 07/05/2023] [Accepted: 07/14/2023] [Indexed: 07/30/2023] Open
Abstract
Potatoes have emerged as a key non-grain crop for food security worldwide. However, the looming threat of climate change poses significant risks to this vital food source, particularly through the projected reduction in crop yields under warmer temperatures. To mitigate potential crises, the development of potato varieties through genome editing holds great promise. In this study, we performed a comprehensive transcriptomic analysis to investigate microtuber development and identified several differentially expressed genes, with a particular focus on ribosomal proteins-RPL11, RPL29, RPL40 and RPL17. Our results reveal, by protein-protein interaction (PPI) network analyses, performed with the highest confidence in the STRING database platform (v11.5), the critical involvement of these ribosomal proteins in microtuber development, and highlighted their interaction with PEBP family members as potential microtuber activators. The elucidation of the molecular biological mechanisms governing ribosomal proteins will help improve the resilience of potato crops in the face of today's changing climatic conditions.
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Affiliation(s)
- Eliana Valencia-Lozano
- Departamento de Ingeniería Genética, Centro de Investigación y de Estudios Avanzados del IPN, Unidad Irapuato, Irapuato 36824, Guanajuato, Mexico
| | - Lisset Herrera-Isidrón
- Unidad Profesional Interdisciplinaria de Ingeniería Campus Guanajuato (UPIIG), Instituto Politécnico Nacional, Av. Mineral de Valenciana 200, Puerto Interior, Silao de la Victoria 36275, Guanajuato, Mexico
| | - Jorge Abraham Flores-López
- Unidad Profesional Interdisciplinaria de Ingeniería Campus Guanajuato (UPIIG), Instituto Politécnico Nacional, Av. Mineral de Valenciana 200, Puerto Interior, Silao de la Victoria 36275, Guanajuato, Mexico
| | - Osiel Salvador Recoder-Meléndez
- Unidad Profesional Interdisciplinaria de Ingeniería Campus Guanajuato (UPIIG), Instituto Politécnico Nacional, Av. Mineral de Valenciana 200, Puerto Interior, Silao de la Victoria 36275, Guanajuato, Mexico
| | - Braulio Uribe-López
- Unidad Profesional Interdisciplinaria de Ingeniería Campus Guanajuato (UPIIG), Instituto Politécnico Nacional, Av. Mineral de Valenciana 200, Puerto Interior, Silao de la Victoria 36275, Guanajuato, Mexico
| | - Aarón Barraza
- CONACYT-Centro de Investigaciones Biológicas del Noreste, SC., Instituto Politécnico Nacional 195, Playa Palo de Santa Rita Sur, La Paz CP 23096, Baja California Sur, Mexico
| | - José Luis Cabrera-Ponce
- Departamento de Ingeniería Genética, Centro de Investigación y de Estudios Avanzados del IPN, Unidad Irapuato, Irapuato 36824, Guanajuato, Mexico
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8
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Ballabani G, Forough M, Kessler F, Shanmugabalaji V. The journey of preproteins across the chloroplast membrane systems. Front Physiol 2023; 14:1213866. [PMID: 37324391 PMCID: PMC10267391 DOI: 10.3389/fphys.2023.1213866] [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: 04/28/2023] [Accepted: 05/22/2023] [Indexed: 06/17/2023] Open
Abstract
The photosynthetic capacity of chloroplasts is vital for autotrophic growth in algae and plants. The origin of the chloroplast has been explained by the endosymbiotic theory that proposes the engulfment of a cyanobacterium by an ancestral eukaryotic cell followed by the transfer of many cyanobacterial genes to the host nucleus. As a result of the gene transfer, the now nuclear-encoded proteins acquired chloroplast targeting peptides (known as transit peptides; transit peptide) and are translated as preproteins in the cytosol. Transit peptides contain specific motifs and domains initially recognized by cytosolic factors followed by the chloroplast import components at the outer and inner envelope of the chloroplast membrane. Once the preprotein emerges on the stromal side of the chloroplast protein import machinery, the transit peptide is cleaved by stromal processing peptidase. In the case of thylakoid-localized proteins, cleavage of the transit peptides may expose a second targeting signal guiding the protein to the thylakoid lumen or allow insertion into the thylakoid membrane by internal sequence information. This review summarizes the common features of targeting sequences and describes their role in routing preproteins to and across the chloroplast envelope as well as the thylakoid membrane and lumen.
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Affiliation(s)
| | | | - Felix Kessler
- *Correspondence: Felix Kessler, ; Venkatasalam Shanmugabalaji,
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9
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Christian R, Labbancz J, Usadel B, Dhingra A. Understanding protein import in diverse non-green plastids. Front Genet 2023; 14:969931. [PMID: 37007964 PMCID: PMC10063809 DOI: 10.3389/fgene.2023.969931] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2022] [Accepted: 02/24/2023] [Indexed: 03/19/2023] Open
Abstract
The spectacular diversity of plastids in non-green organs such as flowers, fruits, roots, tubers, and senescing leaves represents a Universe of metabolic processes in higher plants that remain to be completely characterized. The endosymbiosis of the plastid and the subsequent export of the ancestral cyanobacterial genome to the nuclear genome, and adaptation of the plants to all types of environments has resulted in the emergence of diverse and a highly orchestrated metabolism across the plant kingdom that is entirely reliant on a complex protein import and translocation system. The TOC and TIC translocons, critical for importing nuclear-encoded proteins into the plastid stroma, remain poorly resolved, especially in the case of TIC. From the stroma, three core pathways (cpTat, cpSec, and cpSRP) may localize imported proteins to the thylakoid. Non-canonical routes only utilizing TOC also exist for the insertion of many inner and outer membrane proteins, or in the case of some modified proteins, a vesicular import route. Understanding this complex protein import system is further compounded by the highly heterogeneous nature of transit peptides, and the varying transit peptide specificity of plastids depending on species and the developmental and trophic stage of the plant organs. Computational tools provide an increasingly sophisticated means of predicting protein import into highly diverse non-green plastids across higher plants, which need to be validated using proteomics and metabolic approaches. The myriad plastid functions enable higher plants to interact and respond to all kinds of environments. Unraveling the diversity of non-green plastid functions across the higher plants has the potential to provide knowledge that will help in developing climate resilient crops.
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Affiliation(s)
- Ryan Christian
- Department of Horticulture, Washington State University, Pullman, WA, United States
| | - June Labbancz
- Department of Horticulture, Washington State University, Pullman, WA, United States
- Department of Horticultural Sciences, Texas A&M University, College Station, TX, United States
| | | | - Amit Dhingra
- Department of Horticulture, Washington State University, Pullman, WA, United States
- Department of Horticultural Sciences, Texas A&M University, College Station, TX, United States
- *Correspondence: Amit Dhingra,
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10
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Rong Y, Jensen SI, Lindorff-Larsen K, Nielsen AT. Folding of heterologous proteins in bacterial cell factories: Cellular mechanisms and engineering strategies. Biotechnol Adv 2023; 63:108079. [PMID: 36528238 DOI: 10.1016/j.biotechadv.2022.108079] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2022] [Revised: 11/20/2022] [Accepted: 12/09/2022] [Indexed: 12/23/2022]
Abstract
The expression of correctly folded and functional heterologous proteins is important in many biotechnological production processes, whether it is enzymes, biopharmaceuticals or biosynthetic pathways for production of sustainable chemicals. For industrial applications, bacterial platform organisms, such as E. coli, are still broadly used due to the availability of tools and proven suitability at industrial scale. However, expression of heterologous proteins in these organisms can result in protein aggregation and low amounts of functional protein. This review provides an overview of the cellular mechanisms that can influence protein folding and expression, such as co-translational folding and assembly, chaperone binding, as well as protein quality control, across different model organisms. The knowledge of these mechanisms is then linked to different experimental methods that have been applied in order to improve functional heterologous protein folding, such as codon optimization, fusion tagging, chaperone co-production, as well as strain and protein engineering strategies.
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Affiliation(s)
- Yixin Rong
- The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Kemitorvet, 2800 Kgs. Lyngby, Denmark
| | - Sheila Ingemann Jensen
- The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Kemitorvet, 2800 Kgs. Lyngby, Denmark
| | - Kresten Lindorff-Larsen
- Structural Biology and NMR Laboratory, Department of Biology, University of Copenhagen, Ole Maaloes Vej 5, 2200 Copenhagen N, Denmark
| | - Alex Toftgaard Nielsen
- The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Kemitorvet, 2800 Kgs. Lyngby, Denmark.
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11
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Gallardo-Martínez AM, Jiménez-López J, Hernández ML, Pérez-Ruiz JM, Cejudo FJ. Plastid 2-Cys peroxiredoxins are essential for embryogenesis in Arabidopsis. Redox Biol 2023; 62:102645. [PMID: 36898225 PMCID: PMC10020101 DOI: 10.1016/j.redox.2023.102645] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2022] [Revised: 02/08/2023] [Accepted: 02/23/2023] [Indexed: 03/05/2023] Open
Abstract
The redox couple formed by NADPH-dependent thioredoxin reductase C (NTRC) and 2-Cys peroxiredoxins (Prxs) allows fine-tuning chloroplast performance in response to light intensity changes. Accordingly, the Arabidopsis 2cpab mutant lacking 2-Cys Prxs shows growth inhibition and sensitivity to light stress. However, this mutant also shows defective post-germinative growth, suggesting a relevant role of plastid redox systems in seed development, which is so far unknown. To address this issue, we first analyzed the pattern of expression of NTRC and 2-Cys Prxs in developing seeds. Transgenic lines expressing GFP fusions of these proteins showed their expression in developing embryos, which was low at the globular stage and increased at heart and torpedo stages, coincident with embryo chloroplast differentiation, and confirmed the plastid localization of these enzymes. The 2cpab mutant produced white and abortive seeds, which contained lower and altered composition of fatty acids, thus showing the relevance of 2-Cys Prxs in embryogenesis. Most embryos of white and abortive seeds of the 2cpab mutant were arrested at heart and torpedo stages of embryogenesis suggesting an essential function of 2-Cys Prxs in embryo chloroplast differentiation. This phenotype was not recovered by a mutant version of 2-Cys Prx A replacing the peroxidatic Cys by Ser. Neither the lack nor the overexpression of NTRC had any effect on seed development indicating that the function of 2-Cys Prxs at these early stages of development is independent of NTRC, in clear contrast with the operation of these regulatory redox systems in leaves chloroplasts.
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Affiliation(s)
- Antonia M Gallardo-Martínez
- Instituto de Bioquímica Vegetal y Fotosíntesis, Universidad de Sevilla and CSIC, Avda. Américo Vespucio, 49, 41092, Sevilla, Spain.
| | - Julia Jiménez-López
- Instituto de Bioquímica Vegetal y Fotosíntesis, Universidad de Sevilla and CSIC, Avda. Américo Vespucio, 49, 41092, Sevilla, Spain.
| | - María Luisa Hernández
- Instituto de Bioquímica Vegetal y Fotosíntesis, Universidad de Sevilla and CSIC, Avda. Américo Vespucio, 49, 41092, Sevilla, Spain.
| | - Juan Manuel Pérez-Ruiz
- Instituto de Bioquímica Vegetal y Fotosíntesis, Universidad de Sevilla and CSIC, Avda. Américo Vespucio, 49, 41092, Sevilla, Spain.
| | - Francisco Javier Cejudo
- Instituto de Bioquímica Vegetal y Fotosíntesis, Universidad de Sevilla and CSIC, Avda. Américo Vespucio, 49, 41092, Sevilla, Spain.
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12
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Cloning of an Albino Mutation of Arabidopsis thaliana Using Mapping-by-Sequencing. Int J Mol Sci 2023; 24:ijms24044196. [PMID: 36835605 PMCID: PMC9964061 DOI: 10.3390/ijms24044196] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2022] [Revised: 02/15/2023] [Accepted: 02/16/2023] [Indexed: 02/22/2023] Open
Abstract
We report the molecular characterization of an ethyl methanesulfonate (EMS)-induced mutation that causes albinism and lethality at the seedling stage in Arabidopsis thaliana. We identified the mutation using a mapping-by-sequencing approach that uses Fisher's exact tests to detect changes in allele frequencies among the seedlings of an F2 mapping population, which had been pooled according to their phenotypes (wild-type or mutant). After purifying genomic DNA from the plants of both pools, the two samples were sequenced using the Illumina HiSeq 2500 next-generation sequencing platform. The bioinformatic analysis allowed us to identify a point mutation that damages a conserved residue at the acceptor site of an intron of the At2g04030 gene, which encodes the chloroplast-localized AtHsp90.5 protein, a member of the HSP90 family of heat shock proteins. Our RNA-seq analysis demonstrates that the new allele alters the splicing of At2g04030 transcripts in multiple ways, leading to massive deregulation of genes encoding plastid-localized proteins. A search for protein-protein interactions using the yeast two-hybrid method allowed us to identify two members of the GrpE superfamily as potential interactors of AtHsp90.5, as has previously been reported for green algae.
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13
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Shi J, Jiang M, Wang H, Luo Z, Guo Y, Chen Y, Zhao X, Qiang S, Strasser RJ, Kalaji HM, Chen S. Effects of Mycotoxin Fumagillin, Mevastatin, Radicicol, and Wortmannin on Photosynthesis of Chlamydomonas reinhardtii. PLANTS (BASEL, SWITZERLAND) 2023; 12:plants12030665. [PMID: 36771749 PMCID: PMC9920790 DOI: 10.3390/plants12030665] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/17/2023] [Revised: 01/30/2023] [Accepted: 01/31/2023] [Indexed: 05/12/2023]
Abstract
Mycotoxins are one of the most important sources for the discovery of new pesticides and drugs because of their chemical structural diversity and fascinating bioactivity as well as unique novel targets. Here, the effects of four mycotoxins, fumagillin, mevastatin, radicicol, and wortmannin, on photosynthesis were investigated to identify their precise sites of action on the photosynthetic apparatus of Chlamydomonas reinhardtii. Our results showed that these four mycotoxins have multiple targets, acting mainly on photosystem II (PSII). Their mode of action is similar to that of diuron, inhibiting electron flow beyond the primary quinone electron acceptor (QA) by binding to the secondary quinone electron acceptor (QB) site of the D1 protein, thereby affecting photosynthesis. The results of PSII oxygen evolution rate and chlorophyll (Chl) a fluorescence imaging suggested that fumagillin strongly inhibited overall PSII activity; the other three toxins also exhibited a negative influence at the high concentration. Chl a fluorescence kinetics and the JIP test showed that the inhibition of electron transport beyond QA was the most significant feature of the four mycotoxins. Fumagillin decreased the rate of O2 evolution by interrupting electron transfer on the PSII acceptor side, and had multiple negative effects on the primary photochemical reaction and PSII antenna size. Mevastatin caused a decrease in photosynthetic activity, mainly due to the inhibition of electron transport. Both radicicol and wortmannin decreased photosynthetic efficiency, mainly by inhibiting the electron transport efficiency of the PSII acceptor side and the activity of the PSII reaction centers. In addition, radicicol reduced the primary photochemical reaction efficiency and antenna size. The simulated molecular model of the four mycotoxins' binding to C. reinhardtii D1 protein indicated that the residue D1-Phe265 is their common site at the QB site. This is a novel target site different from those of commercial PSII herbicides. Thus, the interesting effects of the four mycotoxins on PSII suggested that they provide new ideas for the design of novel and efficient herbicide molecules.
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Affiliation(s)
- Jiale Shi
- Weed Research Laboratory, Nanjing Agricultural University, Nanjing 210095, China
| | - Mengyun Jiang
- Weed Research Laboratory, Nanjing Agricultural University, Nanjing 210095, China
| | - He Wang
- Weed Research Laboratory, Nanjing Agricultural University, Nanjing 210095, China
| | - Zhi Luo
- Weed Research Laboratory, Nanjing Agricultural University, Nanjing 210095, China
| | - Yanjing Guo
- Weed Research Laboratory, Nanjing Agricultural University, Nanjing 210095, China
| | - Ying Chen
- Weed Research Laboratory, Nanjing Agricultural University, Nanjing 210095, China
| | - Xiaoxi Zhao
- Weed Research Laboratory, Nanjing Agricultural University, Nanjing 210095, China
| | - Sheng Qiang
- Weed Research Laboratory, Nanjing Agricultural University, Nanjing 210095, China
| | - Reto Jörg Strasser
- Weed Research Laboratory, Nanjing Agricultural University, Nanjing 210095, China
- Bioenergetics Laboratory, University of Geneva, CH-1254 Jussy, Geneva, Switzerland
| | - Hazem M. Kalaji
- Department of Plant Physiology, Institute of Biology, Warsaw University of Life Sciences SGGW, Nowoursynowska 159, 02-776 Warsaw, Poland
| | - Shiguo Chen
- Weed Research Laboratory, Nanjing Agricultural University, Nanjing 210095, China
- Correspondence:
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14
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Kim DB, Na C, Hwang I, Lee DW. Understanding protein translocation across chloroplast membranes: Translocons and motor proteins. JOURNAL OF INTEGRATIVE PLANT BIOLOGY 2023; 65:408-416. [PMID: 36223071 DOI: 10.1111/jipb.13385] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/29/2022] [Accepted: 10/11/2022] [Indexed: 06/16/2023]
Abstract
Subcellular organelles in eukaryotes are surrounded by lipid membranes. In an endomembrane system, vesicle trafficking is the primary mechanism for the delivery of organellar proteins to specific organelles. However, organellar proteins for chloroplasts, mitochondria, the nucleus, and peroxisomes that are translated in the cytosol are directly imported into their target organelles. Chloroplasts are a plant-specific organelle with outer and inner envelope membranes, a dual-membrane structure that is similar to mitochondria. Interior chloroplast proteins translated by cytosolic ribosomes are thus translocated through TOC and TIC complexes (translocons in the outer and inner envelope of chloroplasts, respectively), with stromal ATPase motor proteins playing a critical role in pulling pre-proteins through these import channels. Over the last three decades, the identity and function of TOC/TIC components and stromal motor proteins have been actively investigated, which has shed light on the action mechanisms at a molecular level. However, there remains some disagreement over the exact composition of TIC complexes and genuine stromal motor proteins. In this review, we discuss recent findings on the mechanisms by which proteins are translocated through TOC/TIC complexes and discuss future prospects for this field of research.
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Affiliation(s)
- Da Been Kim
- Department of Integrative Food, Bioscience and Biotechnology, Chonnam National University, Gwangju, 61186, Korea
| | - Changhee Na
- Department of Integrative Food, Bioscience and Biotechnology, Chonnam National University, Gwangju, 61186, Korea
| | - Inhwan Hwang
- Department of Life Sciences, Pohang University of Science and Technology, Pohang, 37673, Korea
| | - Dong Wook Lee
- Department of Integrative Food, Bioscience and Biotechnology, Chonnam National University, Gwangju, 61186, Korea
- Department of Bioenergy Science and Technology, Chonnam National University, Gwangju, 61186, Korea
- Kumho Life Science Laboratory, Chonnam National University, Gwangju, 61186, Korea
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15
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Gao LL, Hong ZH, Wang Y, Wu GZ. Chloroplast proteostasis: A story of birth, life, and death. PLANT COMMUNICATIONS 2023; 4:100424. [PMID: 35964157 PMCID: PMC9860172 DOI: 10.1016/j.xplc.2022.100424] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/16/2022] [Revised: 08/02/2022] [Accepted: 08/10/2022] [Indexed: 06/02/2023]
Abstract
Protein homeostasis (proteostasis) is a dynamic balance of protein synthesis and degradation. Because of the endosymbiotic origin of chloroplasts and the massive transfer of their genetic information to the nucleus of the host cell, many protein complexes in the chloroplasts are constituted from subunits encoded by both genomes. Hence, the proper function of chloroplasts relies on the coordinated expression of chloroplast- and nucleus-encoded genes. The biogenesis and maintenance of chloroplast proteostasis are dependent on synthesis of chloroplast-encoded proteins, import of nucleus-encoded chloroplast proteins from the cytosol, and clearance of damaged or otherwise undesired "old" proteins. This review focuses on the regulation of chloroplast proteostasis, its interaction with proteostasis of the cytosol, and its retrograde control over nuclear gene expression. We also discuss significant issues and perspectives for future studies and potential applications for improving the photosynthetic performance and stress tolerance of crops.
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Affiliation(s)
- Lin-Lin Gao
- Shanghai Collaborative Innovation Center of Agri-Seeds, School of Agriculture and Biology, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240, China; Joint Center for Single Cell Biology, School of Agriculture and Biology, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240, China
| | - Zheng-Hui Hong
- Shanghai Collaborative Innovation Center of Agri-Seeds, School of Agriculture and Biology, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240, China; Joint Center for Single Cell Biology, School of Agriculture and Biology, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240, China
| | - Yinsong Wang
- Shanghai Collaborative Innovation Center of Agri-Seeds, School of Agriculture and Biology, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240, China; Joint Center for Single Cell Biology, School of Agriculture and Biology, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240, China
| | - Guo-Zhang Wu
- Shanghai Collaborative Innovation Center of Agri-Seeds, School of Agriculture and Biology, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240, China; Joint Center for Single Cell Biology, School of Agriculture and Biology, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240, China.
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16
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Rochaix J. Chloroplast protein import machinery and quality control. FEBS J 2022; 289:6908-6918. [PMID: 35472255 PMCID: PMC9790281 DOI: 10.1111/febs.16464] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2022] [Revised: 03/20/2022] [Accepted: 04/25/2022] [Indexed: 01/13/2023]
Abstract
Most chloroplast proteins are nucleus-encoded, translated on cytoplasmic ribosomes as precursor proteins, and imported into chloroplasts through TOC and TIC, the translocons of the outer and inner chloroplast envelope membranes. While the composition of the TOC complex is well established, there is still some controversy about the importance of a recently identified TIC complex consisting of Tic20, Tic214, Tic100, and Tic56. TOC and TIC form a supercomplex with a protein channel at the junction of the outer and inner envelope membranes through which preproteins are pulled into the stroma by the ATP-powered Ycf2 complex consisting of several FtsH-like ATPases and/or by chloroplast Hsp proteins. Several components of the TOC/TIC system are moonlighting proteins with additional roles in chloroplast gene expression and metabolism. Chaperones and co-chaperones, associated with TOC and TIC on the cytoplasmic and stromal side of the chloroplast envelope, participate in the unfolding and folding of the precursor proteins and act together with the ubiquitin-proteasome system in protein quality control. Chloroplast protein import is also intimately linked with retrograde signaling, revealing altogether an unsuspected complexity in the regulation of this process.
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Affiliation(s)
- Jean‐David Rochaix
- Departments of Molecular Biology and Plant BiologyUniversity of GenevaSwitzerland
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17
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Wang Q, Yue J, Zhang C, Yan J. Split-Ubiquitin Two-Hybrid Screen for Proteins Interacting with slToc159-1 and slToc159-2, Two Chloroplast Preprotein Import Receptors in Tomato ( Solanum lycopersicum). PLANTS (BASEL, SWITZERLAND) 2022; 11:2923. [PMID: 36365376 PMCID: PMC9654457 DOI: 10.3390/plants11212923] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/25/2022] [Revised: 10/24/2022] [Accepted: 10/26/2022] [Indexed: 06/16/2023]
Abstract
The post-translational import of nuclear-encoded chloroplast preproteins is critical for chloroplast biogenesis, and the Toc159 family of proteins is the receptor for this process. Our previous work identified and analyzed the Toc GTPase in tomato; however, the tomato-specific transport substrate for Toc159 is still unknown, which limits the study of the function of the TOC receptor in tomato. In this study, we expand the number of preprotein substrates of slToc159 receptor family members using slToc159-1 and slToc159-2 as bait via a split-ubiquitin yeast two-hybrid membrane system. Forty-one specific substrates were identified in tomato for the first time. Using slToc159-1GM and slToc159-2GM as bait, we compared the affinity of the two bait proteins, with and without the A domain, to the precursor protein, which suggested that the A domain endowed the proproteins with subclass specificity. The presence of the A domain enhanced the interaction intensity of slToc159-1 with the photosynthetic preprotein but decreased the interaction intensity of slToc159-2 with the photosynthetic preprotein. Similarly, the presence of the A domain also altered the affinity of slToc159 to non-photosynthetic preproteins. Bimolecular fluorescence complementation (BiFC) analysis showed that A domain had the ability to recognize the preprotein, and the interaction occurred in the chloroplast. Further, the localization of the A domain in Arabidopsis protoplasts showed that the A domain did not contain chloroplast membrane targeting signals. Our data demonstrate the importance of a highly non-conserved A domain, which endows the slToc159 receptor with specificity for different protein types. However, the domain containing the information on targeting the chloroplast needs further study.
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Affiliation(s)
- Qi Wang
- College of Agriculture, Guizhou University, Guiyang 550025, China
- Vegetable Research Academy, Guizhou University, Guiyang 550025, China
| | - Jiang Yue
- College of Agriculture, Guizhou University, Guiyang 550025, China
- Vegetable Research Academy, Guizhou University, Guiyang 550025, China
| | - Chaozhong Zhang
- College of Agriculture, Guizhou University, Guiyang 550025, China
- Vegetable Research Academy, Guizhou University, Guiyang 550025, China
| | - Jianmin Yan
- College of Agriculture, Guizhou University, Guiyang 550025, China
- Vegetable Research Academy, Guizhou University, Guiyang 550025, China
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18
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Wang H, Dong Z, Chen J, Wang M, Ding Y, Xue Q, Liu W, Niu Z, Ding X. Genome-wide identification and expression analysis of the Hsp20, Hsp70 and Hsp90 gene family in Dendrobium officinale. FRONTIERS IN PLANT SCIENCE 2022; 13:979801. [PMID: 36035705 PMCID: PMC9399769 DOI: 10.3389/fpls.2022.979801] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/28/2022] [Accepted: 07/19/2022] [Indexed: 06/15/2023]
Abstract
Dendrobium officinale, an important orchid plant with great horticultural and medicinal values, frequently suffers from abiotic or biotic stresses in the wild, which may influence its well-growth. Heat shock proteins (Hsps) play essential roles in the abiotic stress response of plants. However, they have not been systematically investigated in D. officinale. Here, we identified 37 Hsp20 genes (DenHsp20s), 43 Hsp70 genes (DenHsp70s) and 4 Hsp90 genes (DenHsp90s) in D. officinale genome. These genes were classified into 8, 4 and 2 subfamilies based on phylogenetic analysis and subcellular predication, respectively. Sequence analysis showed that the same subfamily members have relatively conserved gene structures and similar protein motifs. Moreover, we identified 33 pairs of paralogs containing 30 pairs of tandem duplicates and 3 pairs of segmental duplicates among these genes. There were 7 pairs in DenHsp70s under positive selection, which may have important functions in helping cells withstand extreme stress. Numerous gene promoter sequences contained stress and hormone response cis-elements, especially light and MeJA response elements. Under MeJA stress, DenHsp20s, DenHsp70s and DenHsp90s responded to varying degrees, among which DenHsp20-5,6,7,16 extremely up-regulated, which may have a strong stress resistance. Therefore, these findings could provide useful information for evolutional and functional investigations of Hsp20, Hsp70 and Hsp90 genes in D. officinale.
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Affiliation(s)
- Hongman Wang
- College of Life Sciences, Nanjing Normal University, Nanjing, China
- Jiangsu Provincial Engineering Research Center for Technical Industrialization for Dendrobium, Nanjing, China
| | - Zuqi Dong
- College of Life Sciences, Nanjing Normal University, Nanjing, China
- Jiangsu Provincial Engineering Research Center for Technical Industrialization for Dendrobium, Nanjing, China
- College of Forestry, Beijing Forestry University, Beijing, China
| | - Jianbing Chen
- College of Forestry, Beijing Forestry University, Beijing, China
| | - Meng Wang
- College of Forestry, Beijing Forestry University, Beijing, China
| | - Yuting Ding
- College of Forestry, Beijing Forestry University, Beijing, China
| | - Qingyun Xue
- College of Life Sciences, Nanjing Normal University, Nanjing, China
- Jiangsu Provincial Engineering Research Center for Technical Industrialization for Dendrobium, Nanjing, China
| | - Wei Liu
- College of Life Sciences, Nanjing Normal University, Nanjing, China
- Jiangsu Provincial Engineering Research Center for Technical Industrialization for Dendrobium, Nanjing, China
| | - Zhitao Niu
- College of Life Sciences, Nanjing Normal University, Nanjing, China
- Jiangsu Provincial Engineering Research Center for Technical Industrialization for Dendrobium, Nanjing, China
| | - Xiaoyu Ding
- College of Life Sciences, Nanjing Normal University, Nanjing, China
- Jiangsu Provincial Engineering Research Center for Technical Industrialization for Dendrobium, Nanjing, China
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19
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Mankovich AG, Freeman BC. Regulation of Protein Transport Pathways by the Cytosolic Hsp90s. Biomolecules 2022; 12:biom12081077. [PMID: 36008972 PMCID: PMC9406046 DOI: 10.3390/biom12081077] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2022] [Revised: 07/26/2022] [Accepted: 07/27/2022] [Indexed: 11/16/2022] Open
Abstract
The highly conserved molecular chaperone heat shock protein 90 (Hsp90) is well-known for maintaining metastable proteins and mediating various aspects of intracellular protein dynamics. Intriguingly, high-throughput interactome studies suggest that Hsp90 is associated with a variety of other pathways. Here, we will highlight the potential impact of Hsp90 in protein transport. Currently, a limited number of studies have defined a few mechanistic contributions of Hsp90 to protein transport, yet the relevance of hundreds of additional connections between Hsp90 and factors known to aide this process remains unresolved. These interactors broadly support transport pathways including endocytic and exocytic vesicular transport, the transfer of polypeptides across membranes, or unconventional protein secretion. In resolving how Hsp90 contributes to the protein transport process, new therapeutic targets will likely be obtained for the treatment of numerous human health issues, including bacterial infection, cancer metastasis, and neurodegeneration.
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20
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BAG9 Confers Thermotolerance by Regulating Cellular Redox Homeostasis and the Stability of Heat Shock Proteins in Solanum lycopersicum. Antioxidants (Basel) 2022; 11:antiox11081467. [PMID: 36009189 PMCID: PMC9404849 DOI: 10.3390/antiox11081467] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2022] [Revised: 07/20/2022] [Accepted: 07/25/2022] [Indexed: 02/04/2023] Open
Abstract
The Bcl-2-associated athanogene (BAG) family, a group of co-chaperones that share conservative domains in flora and fauna, is involved in plant growth, development, and stress tolerance. However, the function of tomato BAG genes on thermotolerance remains largely unknown. Herein, we found that the expression of BAG9 was induced during heat stress in tomato plants. Knockout of the BAG9 gene by CRISPR/Cas9 reduced, while its overexpression increased thermotolerance in tomato plants as reflected by the phenotype, photosynthesis rate, and membrane peroxidation. Heat-induced reactive oxygen species and oxidative/oxidized proteins were further increased in bag9 mutants and were normalized in BAG9 overexpressing plants. Furthermore, the activities of antioxidant enzymes, ascorbic acid (AsA)/dehydroascorbic acid (DHA), and reduced glutathione (GSH)/oxidized glutathione (GSSG) were reduced in bag9 mutants and were increased in BAG9 overexpressing plants under heat stress. Additionally, BAG9 interacted with Hsp20 proteins in vitro and in vivo. Accumulation of Hsp proteins induced by heat showed a reduction in bag9 mutants; meanwhile, it was increased in BAG9 overexpressing plants. Thus, BAG9 played a crucial role in response to heat stress by regulating cellular redox homeostasis and the stability of heat shock proteins.
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21
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Doyle MT, Bernstein HD. Function of the Omp85 Superfamily of Outer Membrane Protein Assembly Factors and Polypeptide Transporters. Annu Rev Microbiol 2022; 76:259-279. [PMID: 35650668 DOI: 10.1146/annurev-micro-033021-023719] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The Omp85 protein superfamily is found in the outer membrane (OM) of all gram-negative bacteria and eukaryotic organelles of bacterial origin. Members of the family catalyze both the membrane insertion of β-barrel proteins and the translocation of proteins across the OM. Although the mechanism(s) by which these proteins function is unclear, striking new insights have emerged from recent biochemical and structural studies. In this review we discuss the entire Omp85 superfamily but focus on the function of the best-studied member, BamA, which is an essential and highly conserved component of the bacterial barrel assembly machinery (BAM). Because BamA has multiple functions that overlap with those of other Omp85 proteins, it is likely the prototypical member of the Omp85 superfamily. Furthermore, BamA has become a protein of great interest because of the recent discovery of small-molecule inhibitors that potentially represent an important new class of antibiotics. Expected final online publication date for the Annual Review of Microbiology, Volume 76 is September 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.
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Affiliation(s)
- Matthew Thomas Doyle
- Genetics and Biochemistry Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland, USA; ,
| | - Harris D Bernstein
- Genetics and Biochemistry Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland, USA; ,
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22
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Amoroso CG, Andolfo G, Capuozzo C, Di Donato A, Martinez C, Tomassoli L, Ercolano MR. Transcriptomic and genomic analysis provides new insights in molecular and genetic processes involved in zucchini ZYMV tolerance. BMC Genomics 2022; 23:371. [PMID: 35578183 PMCID: PMC9109310 DOI: 10.1186/s12864-022-08596-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2020] [Accepted: 04/25/2022] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Cucurbita pepo is highly susceptible to Zucchini yellow mosaic virus (ZYMV) and the resistance found in several wild species cannot be considered as complete or broad-spectrum resistance. In this study, a source of tolerance introgressed in C. pepo (381e) from C. moschata, in True French (TF) background, was investigated 12 days post-inoculation (DPI) at transcriptomic and genomic levels. RESULTS The comparative RNA-sequencing (RNA-Seq) of TF (susceptible to ZYMV) and 381e (tolerant to ZYMV) allowed the evaluation of about 33,000 expressed transcripts and the identification of 146 differentially expressed genes (DEGs) in 381e, mainly involved in photosynthesis, transcription, cytoskeleton organization and callose synthesis. By contrast, the susceptible cultivar TF triggered oxidative processes related to response to biotic stimulus and activated key regulators of plant virus intercellular movement. In addition, the discovery of variants located in transcripts allowed the identification of two chromosome regions rich in Single Nucleotide Polymorphisms (SNPs), putatively introgressed from C. moschata, containing genes exclusively expressed in 381e. CONCLUSION 381e transcriptome analysis confirmed a global improvement of plant fitness by reducing the virus titer and movement. Furthermore, genes implicated in ZYMV tolerance in C. moschata introgressed regions were detected. Our work provides new insight into the plant virus recovery process and a better understanding of the molecular basis of 381e tolerance.
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Affiliation(s)
- C G Amoroso
- Department of Agricultural Science, University of Naples "Federico II", Portici, NA, Naples, Italy
| | - G Andolfo
- Department of Agricultural Science, University of Naples "Federico II", Portici, NA, Naples, Italy
| | - C Capuozzo
- Department of Agricultural Science, University of Naples "Federico II", Portici, NA, Naples, Italy
| | - A Di Donato
- Department of Agricultural Science, University of Naples "Federico II", Portici, NA, Naples, Italy
| | - C Martinez
- Department of Biology and Geology, Research Centers CIAIMBITAL and CeiA3, University of Almería, 04120, Almería, Spain
| | - L Tomassoli
- Consiglio Per La Ricerca in Agricoltura e l'Analisi Dell'Economia Agraria, Research Centre of Plant Control and Certification, Rome, Italy
| | - M R Ercolano
- Department of Agricultural Science, University of Naples "Federico II", Portici, NA, Naples, Italy.
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23
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Li K, Chen R, Tu Z, Nie X, Song B, He C, Xie C, Nie B. Global Screening and Functional Identification of Major HSPs Involved in PVY Infection in Potato. Genes (Basel) 2022; 13:566. [PMID: 35456372 PMCID: PMC9031240 DOI: 10.3390/genes13040566] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2022] [Revised: 03/17/2022] [Accepted: 03/21/2022] [Indexed: 11/17/2022] Open
Abstract
HSP40 (also known as DnaJ), HSP70, and HSP90 are major heat shock protein (HSP) families that play critical roles in plant growth and development and stress adaption. Recently, several members of the three HSP families were reported to be widely involved in the plant host-virus interactions. However, their global expression profiles and core members recruited by viruses are largely unknown. In this study, a total of 89 StDnaJs were identified from a genome-wide survey, and their classification, phylogenetic relationships, chromosomal locations, and gene duplication events were further analyzed. Together with 20 StHSP70s and 7 StHSP90s previously identified in the potato genome, the global expression patterns of the members in 3 HSP families were investigated in 2 potato cultivars during Potato virus Y (PVY) infection using RNA-seq data. Of them, 16 genes (including 8 StDnaJs, 6 StHSP70s, and 2 StHSP90s) were significantly up- or downregulated. Further analysis using qRT-PCR demonstrated that 7 of the 16 genes (StDnaJ06, StDnaJ17, StDnaJ21, StDnaJ63, StHSP70-6, StHSP70-19, and StHSP90.5) were remarkably upregulated in the potato cultivar 'Eshu 3' after PVY infection, implying their potential roles in the potato-PVY compatible interaction. Subsequent virus-induced gene silencing (VIGS) assays showed that silencing of the homologous genes of StDnaJ17, StDnaJ21, StHSP70-6, and StHSP90.5 in Nicotiana. benthamiana plants dramatically reduced the accumulation of PVY, which indicated the four genes may function as susceptibility factors in PVY infection. This study provides candidate genes for exploring the mechanism of potato-PVY compatible interaction and benefits breeding work aiming to produce new cultivars with the ability to grow healthily under PVY infection.
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Affiliation(s)
- Kun Li
- Key Laboratory of Potato Biology and Biotechnology (HZAU), Ministry of Agriculture and Rural Affairs, Huazhong Agricultural University, Wuhan 430070, China; (K.L.); (R.C.); (Z.T.); (B.S.); (C.X.)
- Key Laboratory of Horticulture Plant Biology (HZAU), Ministry of Education, Huazhong Agricultural University, Wuhan 430070, China
| | - Ruhao Chen
- Key Laboratory of Potato Biology and Biotechnology (HZAU), Ministry of Agriculture and Rural Affairs, Huazhong Agricultural University, Wuhan 430070, China; (K.L.); (R.C.); (Z.T.); (B.S.); (C.X.)
- Key Laboratory of Horticulture Plant Biology (HZAU), Ministry of Education, Huazhong Agricultural University, Wuhan 430070, China
- Hunan Provincial Key Laboratory of Crop Germplasm Innovation and Utilization, Hunan Provincial Engineering Research Center for Potatoes, Hunan Agricultural University, Changsha 410128, China;
| | - Zheng Tu
- Key Laboratory of Potato Biology and Biotechnology (HZAU), Ministry of Agriculture and Rural Affairs, Huazhong Agricultural University, Wuhan 430070, China; (K.L.); (R.C.); (Z.T.); (B.S.); (C.X.)
- Key Laboratory of Horticulture Plant Biology (HZAU), Ministry of Education, Huazhong Agricultural University, Wuhan 430070, China
| | - Xianzhou Nie
- Fredericton Research and Development Centre, Agriculture and Agri-Food Canada, 850 Lincoln Road, Fredericton, NB E3B 4Z7, Canada;
| | - Botao Song
- Key Laboratory of Potato Biology and Biotechnology (HZAU), Ministry of Agriculture and Rural Affairs, Huazhong Agricultural University, Wuhan 430070, China; (K.L.); (R.C.); (Z.T.); (B.S.); (C.X.)
- Key Laboratory of Horticulture Plant Biology (HZAU), Ministry of Education, Huazhong Agricultural University, Wuhan 430070, China
| | - Changzheng He
- Hunan Provincial Key Laboratory of Crop Germplasm Innovation and Utilization, Hunan Provincial Engineering Research Center for Potatoes, Hunan Agricultural University, Changsha 410128, China;
| | - Conghua Xie
- Key Laboratory of Potato Biology and Biotechnology (HZAU), Ministry of Agriculture and Rural Affairs, Huazhong Agricultural University, Wuhan 430070, China; (K.L.); (R.C.); (Z.T.); (B.S.); (C.X.)
- Key Laboratory of Horticulture Plant Biology (HZAU), Ministry of Education, Huazhong Agricultural University, Wuhan 430070, China
| | - Bihua Nie
- Key Laboratory of Potato Biology and Biotechnology (HZAU), Ministry of Agriculture and Rural Affairs, Huazhong Agricultural University, Wuhan 430070, China; (K.L.); (R.C.); (Z.T.); (B.S.); (C.X.)
- Key Laboratory of Horticulture Plant Biology (HZAU), Ministry of Education, Huazhong Agricultural University, Wuhan 430070, China
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Sophiarani Y, Chakraborty S. Prediction of microRNAs in Pseudomonas syringae pv. tomato DC3000 and their potential target prediction in Solanum lycopersicum. GENE REPORTS 2021. [DOI: 10.1016/j.genrep.2021.101360] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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25
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Flores R, Navarro B, Delgado S, Serra P, Di Serio F. Viroid pathogenesis: a critical appraisal of the role of RNA silencing in triggering the initial molecular lesion. FEMS Microbiol Rev 2021; 44:386-398. [PMID: 32379313 DOI: 10.1093/femsre/fuaa011] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2019] [Accepted: 05/06/2020] [Indexed: 12/15/2022] Open
Abstract
The initial molecular lesions through which viroids, satellite RNAs and viruses trigger signal cascades resulting in plant diseases are hotly debated. Since viroids are circular non-protein-coding RNAs of ∼250-430 nucleotides, they appear very convenient to address this issue. Viroids are targeted by their host RNA silencing defense, generating viroid-derived small RNAs (vd-sRNAs) that are presumed to direct Argonaute (AGO) proteins to inactivate messenger RNAs, thus initiating disease. Here, we review the existing evidence. Viroid-induced symptoms reveal a distinction. Those attributed to vd-sRNAs from potato spindle tuber viroid and members of the family Pospiviroidae (replicating in the nucleus) are late, non-specific and systemic. In contrast, those attributed to vd-sRNAs from peach latent mosaic viroid (PLMVd) and other members of the family Avsunviroidae (replicating in plastids) are early, specific and local. Remarkably, leaf sectors expressing different PLMVd-induced chloroses accumulate viroid variants with specific pathogenic determinants. Some vd-sRNAs containing such determinant guide AGO1-mediated cleavage of mRNAs that code for proteins regulating chloroplast biogenesis/development. Therefore, the initial lesions and the expected phenotypes are connected by short signal cascades, hence supporting a cause-effect relationship. Intriguingly, one virus satellite RNA initiates disease through a similar mechanism, whereas in the Pospiviroidae and in plant viruses the situation remains uncertain.
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Affiliation(s)
- Ricardo Flores
- Instituto de Biología Molecular y Celular de Plantas (CSIC-UPV), Avenida de los Naranjos s/n 46010, Valencia, Spain
| | - Beatriz Navarro
- Istituto per la Protezione Sostenibile delle Piante, Via Amendola 122/D, 70126 Bari, Italy
| | - Sonia Delgado
- Instituto de Biología Molecular y Celular de Plantas (CSIC-UPV), Avenida de los Naranjos s/n 46010, Valencia, Spain
| | - Pedro Serra
- Instituto de Biología Molecular y Celular de Plantas (CSIC-UPV), Avenida de los Naranjos s/n 46010, Valencia, Spain
| | - Francesco Di Serio
- Istituto per la Protezione Sostenibile delle Piante, Via Amendola 122/D, 70126 Bari, Italy
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26
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Yuan H, Pawlowski EG, Yang Y, Sun T, Thannhauser TW, Mazourek M, Schnell D, Li L. Arabidopsis ORANGE protein regulates plastid pre-protein import through interacting with Tic proteins. JOURNAL OF EXPERIMENTAL BOTANY 2021; 72:1059-1072. [PMID: 33165598 DOI: 10.1093/jxb/eraa528] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/28/2020] [Accepted: 10/30/2020] [Indexed: 05/19/2023]
Abstract
Chloroplast-targeted proteins are actively imported into chloroplasts via the machinery spanning the double-layered membranes of chloroplasts. While the key translocons at the outer (TOC) and inner (TIC) membranes of chloroplasts are defined, proteins that interact with the core components to facilitate pre-protein import are continuously being discovered. A DnaJ-like chaperone ORANGE (OR) protein is known to regulate carotenoid biosynthesis as well as plastid biogenesis and development. In this study, we found that OR physically interacts with several Tic proteins including Tic20, Tic40, and Tic110 in the classic TIC core complex of the chloroplast import machinery. Knocking out or and its homolog or-like greatly affects the import efficiency of some photosynthetic and non-photosynthetic pre-proteins. Consistent with the direct interactions of OR with Tic proteins, the binding efficiency assay revealed that the effect of OR occurs at translocation at the inner envelope membrane (i.e. at the TIC complex). OR is able to reduce the Tic40 protein turnover rate through its chaperone activity. Moreover, OR was found to interfere with the interaction between Tic40 and Tic110, and reduces the binding of pre-proteins to Tic110 in aiding their release for translocation and processing. Our findings suggest that OR plays a new and regulatory role in stabilizing key translocons and in facilitating the late stage of plastid pre-protein translocation to regulate plastid pre-protein import.
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Affiliation(s)
- Hui Yuan
- Robert W. Holley Center for Agriculture and Health, USDA-ARS, Cornell University, Ithaca, NY, USA
- Plant Breeding and Genetics Section, School of Integrative Plant Science, Cornell University, Ithaca, NY, USA
| | - Emily G Pawlowski
- Department of Plant Biology, Michigan State University, East Lansing, MI, USA
| | - Yong Yang
- Robert W. Holley Center for Agriculture and Health, USDA-ARS, Cornell University, Ithaca, NY, USA
| | - Tianhu Sun
- Robert W. Holley Center for Agriculture and Health, USDA-ARS, Cornell University, Ithaca, NY, USA
- Plant Breeding and Genetics Section, School of Integrative Plant Science, Cornell University, Ithaca, NY, USA
| | - Theodore W Thannhauser
- Robert W. Holley Center for Agriculture and Health, USDA-ARS, Cornell University, Ithaca, NY, USA
| | - Michael Mazourek
- Plant Breeding and Genetics Section, School of Integrative Plant Science, Cornell University, Ithaca, NY, USA
| | - Danny Schnell
- Department of Plant Biology, Michigan State University, East Lansing, MI, USA
| | - Li Li
- Robert W. Holley Center for Agriculture and Health, USDA-ARS, Cornell University, Ithaca, NY, USA
- Plant Breeding and Genetics Section, School of Integrative Plant Science, Cornell University, Ithaca, NY, USA
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27
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Sertse D, You FM, Ravichandran S, Soto-Cerda BJ, Duguid S, Cloutier S. Loci harboring genes with important role in drought and related abiotic stress responses in flax revealed by multiple GWAS models. TAG. THEORETICAL AND APPLIED GENETICS. THEORETISCHE UND ANGEWANDTE GENETIK 2021; 134:191-212. [PMID: 33047220 DOI: 10.1007/s00122-020-03691-0] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/08/2020] [Accepted: 09/18/2020] [Indexed: 05/19/2023]
Abstract
QTNs associated with drought tolerance traits and indices were identified in a flax mini-core collection through multiple GWAS models and phenotyping at multiple locations under irrigated and non-irrigated field conditions. Drought is a critical phenomenon challenging today's agricultural sector. Crop varieties adapted to moisture deficit are becoming vital. Flax can be greatly affected by limiting moisture conditions, especially during the early development and reproductive stages. Here, a mini-core collection comprising genotypes from more than 20 major growing countries was evaluated for 11 drought-related traits in irrigated and non-irrigated fields for 3 years. Heritability of the traits ranged from 44.7 to 86%. Six of the 11 traits showed significant phenotypic difference between irrigated and non-irrigated conditions. A genome-wide association study (GWAS) was performed for these six traits and their corresponding stress indices based on 106 genotypes and 12,316 single nucleotide polymorphisms (SNPs) using six multi-locus and one single-locus models. The SNPs were then assigned to 8050 linkage disequilibrium (LD) blocks to which a restricted two-stage multi-locus multi-allele GWAS was applied. A total of 144 quantitative trait nucleotides (QTNs) and 13 LD blocks were associated with at least one trait or stress index. Of these, 16 explained more than 15% of the genetic variance. Most large-effect QTN loci harbored gene(s) previously predicted to play role(s) in the associated traits. Genes mediating responses to abiotic stresses resided at loci associated with stress indices. Flax genes Lus10009480 and Lus10030150 that are predicted to encode WAX INDUCER1 and STRESS-ASSOCIATED PROTEIN (SAP), respectively, are among the important candidates detected. Accessions with multiple favorable alleles outperformed others for grain yield, thousand seed weight and fiber/biomass in non-irrigated conditions, suggesting their potential usefulness in breeding and genomic selection.
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Affiliation(s)
- Demissew Sertse
- Department of Biology, University of Ottawa, 30 Marie Curie, Ottawa, ON, Canada
- Ottawa Research and Development Centre, Agriculture and Agri-Food Canada, 960 Carling Avenue, Ottawa, ON, Canada
| | - Frank M You
- Ottawa Research and Development Centre, Agriculture and Agri-Food Canada, 960 Carling Avenue, Ottawa, ON, Canada
| | - Sridhar Ravichandran
- Ottawa Research and Development Centre, Agriculture and Agri-Food Canada, 960 Carling Avenue, Ottawa, ON, Canada
| | - Braulio J Soto-Cerda
- Agriaquaculture Nutritional Genomic Centre (CGNA), Las Heras 350, 4781158, Temuco, Chile
| | - Scott Duguid
- Morden Research and Development Centre, Agriculture and Agri-Food Canada, 101 Route 100, Morden, MB, Canada
| | - Sylvie Cloutier
- Department of Biology, University of Ottawa, 30 Marie Curie, Ottawa, ON, Canada.
- Ottawa Research and Development Centre, Agriculture and Agri-Food Canada, 960 Carling Avenue, Ottawa, ON, Canada.
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28
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Jiang T, Mu B, Zhao R. Plastid chaperone HSP90C guides precursor proteins to the SEC translocase for thylakoid transport. JOURNAL OF EXPERIMENTAL BOTANY 2020; 71:7073-7087. [PMID: 32853383 PMCID: PMC7906790 DOI: 10.1093/jxb/eraa399] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/19/2020] [Accepted: 08/24/2020] [Indexed: 05/04/2023]
Abstract
Chloroplast stromal factors involved in regulating thylakoid protein targeting are poorly understood. We previously reported that in Arabidopsis thaliana, the stromal-localized chaperone HSP90C (plastid heat shock protein 90) interacted with the nuclear-encoded thylakoid lumen protein PsbO1 (PSII subunit O isoform 1) and suggested a role for HSP90C in aiding PsbO1 thylakoid targeting. Using in organello transport assays, particularly with model substrates naturally expressed in stroma, we showed that light, exogenous ATP, and HSP90C activity were required for Sec-dependent transport of green fluorescent protein (GFP) led by the PsbO1 thylakoid targeting sequence. Using a previously identified PsbO1T200A mutant, we provided evidence that a stronger interaction between HSP90C and PsbO1 better facilitated its stroma-thylakoid trafficking. We also demonstrated that SecY1, the channel protein of the thylakoid SEC translocase, specifically interacted with HSP90C in vivo. Inhibition of the chaperone ATPase activity suppressed the association of the PsbO1GFP-HSP90C complex with SecY1. Together with analyzing the expression and accumulation of a few other thylakoid proteins that utilize the SRP, TAT, or SEC translocation pathways, we propose a model in which HSP90C forms a guiding complex that interacts with thylakoid protein precursors and assists in their specific targeting to the thylakoid SEC translocon.
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Affiliation(s)
- Tim Jiang
- Department of Biological Sciences, University of Toronto Scarborough, Toronto, Ontario, Canada
- Department of Cell and Systems Biology, University of Toronto, Toronto, Ontario, Canada
| | - Bona Mu
- Department of Biological Sciences, University of Toronto Scarborough, Toronto, Ontario, Canada
- Department of Cell and Systems Biology, University of Toronto, Toronto, Ontario, Canada
| | - Rongmin Zhao
- Department of Biological Sciences, University of Toronto Scarborough, Toronto, Ontario, Canada
- Department of Cell and Systems Biology, University of Toronto, Toronto, Ontario, Canada
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29
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Baslam M, Mitsui T, Sueyoshi K, Ohyama T. Recent Advances in Carbon and Nitrogen Metabolism in C3 Plants. Int J Mol Sci 2020; 22:E318. [PMID: 33396811 PMCID: PMC7795015 DOI: 10.3390/ijms22010318] [Citation(s) in RCA: 44] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2020] [Revised: 12/23/2020] [Accepted: 12/23/2020] [Indexed: 12/19/2022] Open
Abstract
C and N are the most important essential elements constituting organic compounds in plants. The shoots and roots depend on each other by exchanging C and N through the xylem and phloem transport systems. Complex mechanisms regulate C and N metabolism to optimize plant growth, agricultural crop production, and maintenance of the agroecosystem. In this paper, we cover the recent advances in understanding C and N metabolism, regulation, and transport in plants, as well as their underlying molecular mechanisms. Special emphasis is given to the mechanisms of starch metabolism in plastids and the changes in responses to environmental stress that were previously overlooked, since these changes provide an essential store of C that fuels plant metabolism and growth. We present general insights into the system biology approaches that have expanded our understanding of core biological questions related to C and N metabolism. Finally, this review synthesizes recent advances in our understanding of the trade-off concept that links C and N status to the plant's response to microorganisms.
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Affiliation(s)
- Marouane Baslam
- Laboratory of Biochemistry, Faculty of Agriculture, Niigata University, Niigata 950-2181, Japan; (M.B.); (T.M.)
| | - Toshiaki Mitsui
- Laboratory of Biochemistry, Faculty of Agriculture, Niigata University, Niigata 950-2181, Japan; (M.B.); (T.M.)
- Department of Life and Food Sciences, Graduate School of Science and Technology, Niigata University, Niigata 950-2181, Japan;
| | - Kuni Sueyoshi
- Department of Life and Food Sciences, Graduate School of Science and Technology, Niigata University, Niigata 950-2181, Japan;
| | - Takuji Ohyama
- Department of Life and Food Sciences, Graduate School of Science and Technology, Niigata University, Niigata 950-2181, Japan;
- Faculty of Applied Biosciences, Tokyo University of Agriculture, Tokyo 156-8502, Japan
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30
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Ramundo S, Asakura Y, Salomé PA, Strenkert D, Boone M, Mackinder LCM, Takafuji K, Dinc E, Rahire M, Crèvecoeur M, Magneschi L, Schaad O, Hippler M, Jonikas MC, Merchant S, Nakai M, Rochaix JD, Walter P. Coexpressed subunits of dual genetic origin define a conserved supercomplex mediating essential protein import into chloroplasts. Proc Natl Acad Sci U S A 2020; 117:32739-32749. [PMID: 33273113 PMCID: PMC7768757 DOI: 10.1073/pnas.2014294117] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
In photosynthetic eukaryotes, thousands of proteins are translated in the cytosol and imported into the chloroplast through the concerted action of two translocons-termed TOC and TIC-located in the outer and inner membranes of the chloroplast envelope, respectively. The degree to which the molecular composition of the TOC and TIC complexes is conserved over phylogenetic distances has remained controversial. Here, we combine transcriptomic, biochemical, and genetic tools in the green alga Chlamydomonas (Chlamydomonas reinhardtii) to demonstrate that, despite a lack of evident sequence conservation for some of its components, the algal TIC complex mirrors the molecular composition of a TIC complex from Arabidopsis thaliana. The Chlamydomonas TIC complex contains three nuclear-encoded subunits, Tic20, Tic56, and Tic100, and one chloroplast-encoded subunit, Tic214, and interacts with the TOC complex, as well as with several uncharacterized proteins to form a stable supercomplex (TIC-TOC), indicating that protein import across both envelope membranes is mechanistically coupled. Expression of the nuclear and chloroplast genes encoding both known and uncharacterized TIC-TOC components is highly coordinated, suggesting that a mechanism for regulating its biogenesis across compartmental boundaries must exist. Conditional repression of Tic214, the only chloroplast-encoded subunit in the TIC-TOC complex, impairs the import of chloroplast proteins with essential roles in chloroplast ribosome biogenesis and protein folding and induces a pleiotropic stress response, including several proteins involved in the chloroplast unfolded protein response. These findings underscore the functional importance of the TIC-TOC supercomplex in maintaining chloroplast proteostasis.
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Affiliation(s)
- Silvia Ramundo
- Department of Biochemistry and Biophysics, University of California, San Francisco, CA 94143
- Howard Hughes Medical Institute, Chevy Chase, MD 20815
| | - Yukari Asakura
- Laboratory of Organelle Biology, Institute for Protein Research, Osaka University, Osaka 565-0871, Japan
| | - Patrice A Salomé
- Department of Chemistry and Biochemistry, University of California, Los Angeles, CA 90095
| | - Daniela Strenkert
- Department of Chemistry and Biochemistry, University of California, Los Angeles, CA 90095
| | - Morgane Boone
- Department of Biochemistry and Biophysics, University of California, San Francisco, CA 94143
- Howard Hughes Medical Institute, Chevy Chase, MD 20815
| | - Luke C M Mackinder
- Department of Biology, University of York, York YO10 5DD, United Kingdom
| | - Kazuaki Takafuji
- Graduate School of Medicine, Osaka University, Osaka 565-0871, Japan
| | - Emine Dinc
- Department of Molecular Biology, University of Geneva, Geneva CH-1211, Switzerland
- Department of Plant Biology, University of Geneva, Geneva CH-1211, Switzerland
| | - Michèle Rahire
- Department of Molecular Biology, University of Geneva, Geneva CH-1211, Switzerland
- Department of Plant Biology, University of Geneva, Geneva CH-1211, Switzerland
| | - Michèle Crèvecoeur
- Department of Molecular Biology, University of Geneva, Geneva CH-1211, Switzerland
- Department of Plant Biology, University of Geneva, Geneva CH-1211, Switzerland
| | - Leonardo Magneschi
- Institute of Plant Biology and Biotechnology, University of Münster, Münster 48143, Germany
| | - Olivier Schaad
- Department of Biochemistry, University of Geneva, Geneva CH-1211, Switzerland
| | - Michael Hippler
- Institute of Plant Biology and Biotechnology, University of Münster, Münster 48143, Germany
- Institute of Plant Science and Resources, Okayama University, Kurashiki 710-0046, Japan
| | - Martin C Jonikas
- Department of Molecular Biology, Princeton University, Princeton, NJ 08540
- Howard Hughes Medical Institute, Chevy Chase, MD 20815
| | - Sabeeha Merchant
- Department of Chemistry and Biochemistry, University of California, Los Angeles, CA 90095
| | - Masato Nakai
- Laboratory of Organelle Biology, Institute for Protein Research, Osaka University, Osaka 565-0871, Japan;
| | - Jean-David Rochaix
- Department of Molecular Biology, University of Geneva, Geneva CH-1211, Switzerland;
- Department of Plant Biology, University of Geneva, Geneva CH-1211, Switzerland
| | - Peter Walter
- Department of Biochemistry and Biophysics, University of California, San Francisco, CA 94143;
- Howard Hughes Medical Institute, Chevy Chase, MD 20815
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31
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Klasek L, Inoue K, Theg SM. Chloroplast Chaperonin-Mediated Targeting of a Thylakoid Membrane Protein. THE PLANT CELL 2020; 32:3884-3901. [PMID: 33093145 PMCID: PMC7721336 DOI: 10.1105/tpc.20.00309] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/20/2020] [Revised: 08/11/2020] [Accepted: 10/21/2020] [Indexed: 05/08/2023]
Abstract
Posttranslational protein targeting requires chaperone assistance to direct insertion-competent proteins to integration pathways. Chloroplasts integrate nearly all thylakoid transmembrane proteins posttranslationally, but mechanisms in the stroma that assist their insertion remain largely undefined. Here, we investigated how the chloroplast chaperonin (Cpn60) facilitated the thylakoid integration of Plastidic type I signal peptidase 1 (Plsp1) using in vitro targeting assays. Cpn60 bound Plsp1 in the stroma. In isolated chloroplasts, the membrane integration of imported Plsp1 correlated with its dissociation from Cpn60. When the Plsp1 residues that interacted with Cpn60 were removed, Plsp1 did not integrate into the membrane. These results suggested Cpn60 was an intermediate in thylakoid targeting of Plsp1. In isolated thylakoids, the integration of Plsp1 decreased when Cpn60 was present in excess of cpSecA1, the stromal motor of the cpSec1 translocon that inserts unfolded Plsp1 into the thylakoid. An excess of cpSecA1 favored integration. Introducing Cpn60's obligate substrate RbcL displaced Cpn60-bound Plsp1; then, the released Plsp1 exhibited increased accessibility to cpSec1. These in vitro targeting experiments support a model in which Cpn60 captures and then releases insertion-competent Plsp1, whereas cpSecA1 recognizes free Plsp1 for integration. Thylakoid transmembrane proteins in the stroma can interact with Cpn60 to shield themselves from the aqueous environment.
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Affiliation(s)
- Laura Klasek
- Department of Plant Biology, University of California Davis, Davis, California 95616
| | - Kentaro Inoue
- Department of Plant Sciences, University of California Davis, Davis, California 95616
| | - Steven M Theg
- Department of Plant Biology, University of California Davis, Davis, California 95616
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32
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Tichá T, Samakovli D, Kuchařová A, Vavrdová T, Šamaj J. Multifaceted roles of HEAT SHOCK PROTEIN 90 molecular chaperones in plant development. JOURNAL OF EXPERIMENTAL BOTANY 2020; 71:3966-3985. [PMID: 32293686 DOI: 10.1093/jxb/eraa177] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/27/2020] [Accepted: 04/06/2020] [Indexed: 05/20/2023]
Abstract
HEAT SHOCK PROTEINS 90 (HSP90s) are molecular chaperones that mediate correct folding and stability of many client proteins. These chaperones act as master molecular hubs involved in multiple aspects of cellular and developmental signalling in diverse organisms. Moreover, environmental and genetic perturbations affect both HSP90s and their clients, leading to alterations of molecular networks determining respectively plant phenotypes and genotypes and contributing to a broad phenotypic plasticity. Although HSP90 interaction networks affecting the genetic basis of phenotypic variation and diversity have been thoroughly studied in animals, such studies are just starting to emerge in plants. Here, we summarize current knowledge and discuss HSP90 network functions in plant development and cellular homeostasis.
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Affiliation(s)
- Tereza Tichá
- Department of Cell Biology, Centre of the Region Haná for Biotechnological and Agricultural Research, Faculty of Science, Palacký University Olomouc, Olomouc, Czech Republic
| | - Despina Samakovli
- Department of Cell Biology, Centre of the Region Haná for Biotechnological and Agricultural Research, Faculty of Science, Palacký University Olomouc, Olomouc, Czech Republic
| | - Anna Kuchařová
- Department of Cell Biology, Centre of the Region Haná for Biotechnological and Agricultural Research, Faculty of Science, Palacký University Olomouc, Olomouc, Czech Republic
| | - Tereza Vavrdová
- Department of Cell Biology, Centre of the Region Haná for Biotechnological and Agricultural Research, Faculty of Science, Palacký University Olomouc, Olomouc, Czech Republic
| | - Jozef Šamaj
- Department of Cell Biology, Centre of the Region Haná for Biotechnological and Agricultural Research, Faculty of Science, Palacký University Olomouc, Olomouc, Czech Republic
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33
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Islam S, Bhor SA, Tanaka K, Sakamoto H, Yaeno T, Kaya H, Kobayashi K. Impaired Expression of Chloroplast HSP90C Chaperone Activates Plant Defense Responses with a Possible Link to a Disease-Symptom-Like Phenotype. Int J Mol Sci 2020; 21:E4202. [PMID: 32545608 PMCID: PMC7352560 DOI: 10.3390/ijms21124202] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2020] [Revised: 06/10/2020] [Accepted: 06/11/2020] [Indexed: 12/13/2022] Open
Abstract
RNA-seq analysis of a transgenic tobacco plant, i-hpHSP90C, in which chloroplast HSP90C genes can be silenced in an artificially inducible manner resulting in the development of chlorosis, revealed the up- and downregulation of 2746 and 3490 genes, respectively. Gene ontology analysis of these differentially expressed genes indicated the upregulation of ROS-responsive genes; the activation of the innate immunity and cell death pathways; and the downregulation of genes involved in photosynthesis, plastid organization, and cell cycle. Cell death was confirmed by trypan blue staining and electrolyte leakage assay, and the H2O2 production was confirmed by diaminobenzidine staining. The results collectively suggest that the reduced levels of HSP90C chaperone lead the plant to develop chlorosis primarily through the global downregulation of chloroplast- and photosynthesis-related genes and additionally through the light-dependent production of ROS, followed by the activation of immune responses, including cell death.
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Affiliation(s)
- Shaikhul Islam
- The United Graduate School of Agricultural Sciences, Ehime University, Matsuyama, Ehime 790-8566, Japan; (S.I.); (S.A.B.); (T.Y.); (H.K.)
| | - Sachin Ashok Bhor
- The United Graduate School of Agricultural Sciences, Ehime University, Matsuyama, Ehime 790-8566, Japan; (S.I.); (S.A.B.); (T.Y.); (H.K.)
| | - Keisuke Tanaka
- NODAI Genome Research Center, Tokyo University of Agriculture, Setagaya, Tokyo 156-8502, Japan;
| | - Hikaru Sakamoto
- Faculty of Bio-Industry, Tokyo University of Agriculture, Abashiri, Hokkaido 099-2493, Japan;
| | - Takashi Yaeno
- The United Graduate School of Agricultural Sciences, Ehime University, Matsuyama, Ehime 790-8566, Japan; (S.I.); (S.A.B.); (T.Y.); (H.K.)
- Graduate School of Agriculture, Ehime University, Matsuyama, Ehime 790-8566, Japan
- Research Unit for Citromics, Ehime University, Matsuyama, Ehime 790-8566, Japan
| | - Hidetaka Kaya
- The United Graduate School of Agricultural Sciences, Ehime University, Matsuyama, Ehime 790-8566, Japan; (S.I.); (S.A.B.); (T.Y.); (H.K.)
- Graduate School of Agriculture, Ehime University, Matsuyama, Ehime 790-8566, Japan
- Research Unit for Citromics, Ehime University, Matsuyama, Ehime 790-8566, Japan
| | - Kappei Kobayashi
- The United Graduate School of Agricultural Sciences, Ehime University, Matsuyama, Ehime 790-8566, Japan; (S.I.); (S.A.B.); (T.Y.); (H.K.)
- Graduate School of Agriculture, Ehime University, Matsuyama, Ehime 790-8566, Japan
- Research Unit for Citromics, Ehime University, Matsuyama, Ehime 790-8566, Japan
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34
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Protein import into chloroplasts and its regulation by the ubiquitin-proteasome system. Biochem Soc Trans 2020; 48:71-82. [PMID: 31922184 PMCID: PMC7054747 DOI: 10.1042/bst20190274] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2019] [Revised: 12/19/2019] [Accepted: 12/23/2019] [Indexed: 02/08/2023]
Abstract
Chloroplasts are photosynthetic plant organelles descended from a bacterial ancestor. The vast majority of chloroplast proteins are synthesized in the cytosol and then imported into the chloroplast post-translationally. Translocation complexes exist in the organelle's outer and inner envelope membranes (termed TOC and TIC, respectively) to facilitate protein import. These systems recognize chloroplast precursor proteins and mediate their import in an energy-dependent manner. However, many unanswered questions remain regarding mechanistic details of the import process and the participation and functions of individual components; for example, the cytosolic events that mediate protein delivery to chloroplasts, the composition of the TIC apparatus, and the nature of the protein import motor all require resolution. The flux of proteins through TOC and TIC varies greatly throughout development and in response to specific environmental cues. The import process is, therefore, tightly regulated, and it has emerged that the ubiquitin-proteasome system (UPS) plays a key role in this regard, acting at several different steps in the process. The UPS is involved in: the selective degradation of transcription factors that co-ordinate the expression of chloroplast precursor proteins; the removal of unimported chloroplast precursor proteins in the cytosol; the inhibition of chloroplast biogenesis pre-germination; and the reconfiguration of the TOC apparatus in response to developmental and environmental signals in a process termed chloroplast-associated protein degradation. In this review, we highlight recent advances in our understanding of protein import into chloroplasts and how this process is regulated by the UPS.
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Li HM, Schnell D, Theg SM. Protein Import Motors in Chloroplasts: On the Role of Chaperones. THE PLANT CELL 2020; 32:536-542. [PMID: 31932485 PMCID: PMC7054032 DOI: 10.1105/tpc.19.00300] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/25/2019] [Revised: 08/01/2019] [Accepted: 01/08/2020] [Indexed: 05/09/2023]
Affiliation(s)
- Hsou-Min Li
- Institute of Molecular Biology Academia Sinica Taipei 11529, Taiwan
| | - Danny Schnell
- Department of Plant Biology Michigan State University East Lansing, Michigan 48824
| | - Steven M Theg
- Department of Plant Biology University of California Davis, California 95616
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Richardson LGL, Schnell DJ. Origins, function, and regulation of the TOC-TIC general protein import machinery of plastids. JOURNAL OF EXPERIMENTAL BOTANY 2020; 71:1226-1238. [PMID: 31730153 PMCID: PMC7031061 DOI: 10.1093/jxb/erz517] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/01/2019] [Accepted: 11/14/2019] [Indexed: 05/11/2023]
Abstract
The evolution of chloroplasts from the original endosymbiont involved the transfer of thousands of genes from the ancestral bacterial genome to the host nucleus, thereby combining the two genetic systems to facilitate coordination of gene expression and achieve integration of host and organelle functions. A key element of successful endosymbiosis was the evolution of a unique protein import system to selectively and efficiently target nuclear-encoded proteins to their site of function within the chloroplast after synthesis in the cytoplasm. The chloroplast TOC-TIC (translocon at the outer chloroplast envelope-translocon at the inner chloroplast envelope) general protein import system is conserved across the plant kingdom, and is a system of hybrid origin, with core membrane transport components adapted from bacterial protein targeting systems, and additional components adapted from host genes to confer the specificity and directionality of import. In vascular plants, the TOC-TIC system has diversified to mediate the import of specific, functionally related classes of plastid proteins. This functional diversification occurred as the plastid family expanded to fulfill cell- and tissue-specific functions in terrestrial plants. In addition, there is growing evidence that direct regulation of TOC-TIC activities plays an essential role in the dynamic remodeling of the organelle proteome that is required to coordinate plastid biogenesis with developmental and physiological events.
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Affiliation(s)
- Lynn G L Richardson
- Department of Plant Biology, Michigan State University, East Lansing, MI, USA
| | - Danny J Schnell
- Department of Plant Biology, Michigan State University, East Lansing, MI, USA
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Schnell DJ. The TOC GTPase Receptors: Regulators of the Fidelity, Specificity and Substrate Profiles of the General Protein Import Machinery of Chloroplasts. Protein J 2020; 38:343-350. [PMID: 31201619 PMCID: PMC6589150 DOI: 10.1007/s10930-019-09846-3] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
More than 2500 nuclear encoded preproteins are required for the function of chloroplasts in terrestrial plants. These preproteins are imported into chloroplasts via the concerted action of two multi-subunit translocons of the outer (TOC) and inner (TIC) membranes of the chloroplast envelope. This general import machinery functions to recognize and import proteins with high fidelity and efficiency to ensure that organelle biogenesis is properly coordinated with developmental and physiological events. Two components of the TOC machinery, Toc34 and Toc159, act as the primary receptors for preproteins at the chloroplast surface. They interact with the intrinsic targeting signals (transit peptides) of preproteins to mediate the selectivity of targeting, and they contribute to the quality control of import by constituting a GTP-dependent checkpoint in the import reaction. The TOC receptor family has expanded to regulate the import of distinct classes of preproteins that are required for remodeling of organelle proteomes during plastid-type transitions that accompany developmental changes. As such, the TOC receptors function as central regulators of the fidelity, specificity and selectivity of the general import machinery, thereby contributing to the integration of protein import with plastid biogenesis.
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Affiliation(s)
- Danny J Schnell
- Department of Plant Biology, Michigan State University, East Lansing, MI, USA.
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Zhang N, Xu J, Liu X, Liang W, Xin M, Du J, Hu Z, Peng H, Guo W, Ni Z, Sun Q, Yao Y. Identification of HSP90C as a substrate of E3 ligase TaSAP5 through ubiquitylome profiling. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2019; 287:110170. [PMID: 31481192 DOI: 10.1016/j.plantsci.2019.110170] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/13/2019] [Revised: 06/10/2019] [Accepted: 06/12/2019] [Indexed: 06/10/2023]
Abstract
Protein ubiquitination is a major post-translational modification important for diverse biological processes. In wheat (Triticum aestivum) and Arabidopsis thaliana, STRESS-ASSOCIATED PROTEIN 5 (SAP5) is involved in drought tolerance, acting as an E3 ubiquitin ligase to target DRIP and MBP-1 for degradation. To identify further target proteins of SAP5, we implemented two independent approaches in this work. We used ubiquitylome capture with a di-Gly-Lys antibody-based peptide enrichment and affinity purification with a polyubiquitin antibody coupled with mass spectrometry to elucidate the SAP5-dependent ubiquitylation of its target proteins in response to osmotic stress. Wild type or TaSAP5-overexpressing Arabidopsis line, which was more tolerant to osmotic stress according to our previous study, were used here. We identified HSP90C (chloroplast heat shock protein 90) as a substrate of TaSAP5. Further biochemical experiments indicated that TaSAP5 interacts with HSP90C and mediates its degradation by the 26S proteasome. Our work also demonstrates that ubiquitylome profiling is an effective approach to search for substrates of the TaSAP5 E3 ubiquitin ligase when heterologously expressed in Arabidopsis.
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Affiliation(s)
- Ning Zhang
- State Key Laboratory for Agrobiotechnology and Key Laboratory of Crop Heterosis and Utilization (MOE) and Beijing Key Laboratory of Crop Genetic Improvement, China Agricultural University, Beijing, 100193, China
| | - Jing Xu
- State Key Laboratory for Agrobiotechnology and Key Laboratory of Crop Heterosis and Utilization (MOE) and Beijing Key Laboratory of Crop Genetic Improvement, China Agricultural University, Beijing, 100193, China
| | - Xinye Liu
- State Key Laboratory for Agrobiotechnology and Key Laboratory of Crop Heterosis and Utilization (MOE) and Beijing Key Laboratory of Crop Genetic Improvement, China Agricultural University, Beijing, 100193, China
| | - Wenxing Liang
- Key Laboratory of Integrated Crop Pest Management of Shandong Province, College of Plant Health and Medicine, Qingdao Agricultural University, Qingdao, China
| | - Mingming Xin
- State Key Laboratory for Agrobiotechnology and Key Laboratory of Crop Heterosis and Utilization (MOE) and Beijing Key Laboratory of Crop Genetic Improvement, China Agricultural University, Beijing, 100193, China
| | - Jinkun Du
- State Key Laboratory for Agrobiotechnology and Key Laboratory of Crop Heterosis and Utilization (MOE) and Beijing Key Laboratory of Crop Genetic Improvement, China Agricultural University, Beijing, 100193, China
| | - Zhaorong Hu
- State Key Laboratory for Agrobiotechnology and Key Laboratory of Crop Heterosis and Utilization (MOE) and Beijing Key Laboratory of Crop Genetic Improvement, China Agricultural University, Beijing, 100193, China
| | - Huiru Peng
- State Key Laboratory for Agrobiotechnology and Key Laboratory of Crop Heterosis and Utilization (MOE) and Beijing Key Laboratory of Crop Genetic Improvement, China Agricultural University, Beijing, 100193, China
| | - Weilong Guo
- State Key Laboratory for Agrobiotechnology and Key Laboratory of Crop Heterosis and Utilization (MOE) and Beijing Key Laboratory of Crop Genetic Improvement, China Agricultural University, Beijing, 100193, China
| | - Zhongfu Ni
- State Key Laboratory for Agrobiotechnology and Key Laboratory of Crop Heterosis and Utilization (MOE) and Beijing Key Laboratory of Crop Genetic Improvement, China Agricultural University, Beijing, 100193, China
| | - Qixin Sun
- State Key Laboratory for Agrobiotechnology and Key Laboratory of Crop Heterosis and Utilization (MOE) and Beijing Key Laboratory of Crop Genetic Improvement, China Agricultural University, Beijing, 100193, China
| | - Yingyin Yao
- State Key Laboratory for Agrobiotechnology and Key Laboratory of Crop Heterosis and Utilization (MOE) and Beijing Key Laboratory of Crop Genetic Improvement, China Agricultural University, Beijing, 100193, China.
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Biebl MM, Buchner J. Structure, Function, and Regulation of the Hsp90 Machinery. Cold Spring Harb Perspect Biol 2019; 11:cshperspect.a034017. [PMID: 30745292 DOI: 10.1101/cshperspect.a034017] [Citation(s) in RCA: 166] [Impact Index Per Article: 33.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Heat shock protein 90 (Hsp90) is a molecular chaperone involved in the maturation of a plethora of substrates ("clients"), including protein kinases, transcription factors, and E3 ubiquitin ligases, positioning Hsp90 as a central regulator of cellular proteostasis. Hsp90 undergoes large conformational changes during its ATPase cycle. The processing of clients by cytosolic Hsp90 is assisted by a cohort of cochaperones that affect client recruitment, Hsp90 ATPase function or conformational rearrangements in Hsp90. Because of the importance of Hsp90 in regulating central cellular pathways, strategies for the pharmacological inhibition of the Hsp90 machinery in diseases such as cancer and neurodegeneration are being developed. In this review, we summarize recent structural and mechanistic progress in defining the function of organelle-specific and cytosolic Hsp90, including the impact of individual cochaperones on the maturation of specific clients and complexes with clients as well as ways of exploiting Hsp90 as a drug target.
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Affiliation(s)
- Maximilian M Biebl
- Center for Integrated Protein Science, Department of Chemistry, Technische Universität München, D-85748 Garching, Germany
| | - Johannes Buchner
- Center for Integrated Protein Science, Department of Chemistry, Technische Universität München, D-85748 Garching, Germany
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Genetically Modified Heat Shock Protein90s and Polyamine Oxidases in Arabidopsis Reveal Their Interaction under Heat Stress Affecting Polyamine Acetylation, Oxidation and Homeostasis of Reactive Oxygen Species. PLANTS 2019; 8:plants8090323. [PMID: 31484414 PMCID: PMC6783977 DOI: 10.3390/plants8090323] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/22/2019] [Revised: 08/09/2019] [Accepted: 08/12/2019] [Indexed: 11/24/2022]
Abstract
One Sentence Summary Heat shock proteins90 (HSP90s) induce acetylation of polyamines (PAs) and interact with polyamine oxidases (PAOs) affecting oxidation of PAs and hydrogen peroxide (H2O2) homeostasis in Arabidopsis thaliana. Abstract The chaperones, heat shock proteins (HSPs), stabilize proteins to minimize proteotoxic stress, especially during heat stress (HS) and polyamine (PA) oxidases (PAOs) participate in the modulation of the cellular homeostasis of PAs and reactive oxygen species (ROS). An interesting interaction of HSP90s and PAOs was revealed in Arabidopsis thaliana by using the pLFY:HSP90RNAi line against the four AtHSP90 genes encoding cytosolic proteins, the T-DNA Athsp90-1 and Athsp90-4 insertional mutants, the Atpao3 mutant and pharmacological inhibitors of HSP90s and PAOs. Silencing of all cytosolic HSP90 genes resulted in several-fold higher levels of soluble spermidine (S-Spd), acetylated Spd (N8-acetyl-Spd) and acetylated spermine (N1-acetyl-Spm) in the transgenic Arabidopsis thaliana leaves. Heat shock induced increase of soluble-PAs (S-PAs) and soluble hydrolyzed-PAs (SH-PAs), especially of SH-Spm, and more importantly of acetylated Spd and Spm. The silencing of HSP90 genes or pharmacological inhibition of the HSP90 proteins by the specific inhibitor radicicol, under HS stimulatory conditions, resulted in a further increase of PA titers, N8-acetyl-Spd and N1-acetyl-Spm, and also stimulated the expression of PAO genes. The increased PA titers and PAO enzymatic activity resulted in a profound increase of PAO-derived hydrogen peroxide (H2O2) levels, which was terminated by the addition of the PAO-specific inhibitor guazatine. Interestingly, the loss-of-function Atpao3 mutant exhibited increased mRNA levels of selected AtHSP90 genes. Taken together, the results herein reveal a novel function of HSP90 and suggest that HSP90s and PAOs cross-talk to orchestrate PA acetylation, oxidation, and PA/H2O2 homeostasis.
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Protein import into chloroplasts via the Tic40-dependent and -independent pathways depends on the amino acid composition of the transit peptide. Biochem Biophys Res Commun 2019; 518:66-71. [PMID: 31400859 DOI: 10.1016/j.bbrc.2019.08.009] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2019] [Accepted: 08/03/2019] [Indexed: 11/23/2022]
Abstract
Preprotein import into chloroplasts is mediated by the coordinated actions of translocons at the outer and inner envelopes of chloroplasts (Toc and Tic, respectively). The cleavable N-terminal transit peptide (TP) of preproteins plays an essential role in the import of preproteins into chloroplasts. The Tic40 protein, a component of the Tic complex, is believed to mediate the import of preproteins through the inner envelope. In this study, we aimed to obtain in vivo evidence supporting the role of Tic40 in preprotein import into chloroplasts. Contrary to previous findings, the import of various preproteins with wild-type TPs showed no difference between tic40 and wild-type protoplasts of Arabidopsis thaliana. However, the import of N-terminal mutants of the RbcS protein (RbcS-nt), in which basic amino acid residues (arginine and lysine) in the central region of the TP were substituted with neutral (alanine) or acidic (glutamic acid) amino acid residues, was dependent on Tic40. In addition, in tic40 protoplasts, the inner envelope protein Tic40 tagged with HA (hemagglutinin) showed more intermediate form present in the stroma. Based on these results, we propose that protein can be imported into chloroplast by either Tic40-independent or Tic40-dependent pathways depending on the types of TP.
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42
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Donato M, Geisler M. HSP
90 and co‐chaperones: a multitaskers’ view on plant hormone biology. FEBS Lett 2019; 593:1415-1430. [DOI: 10.1002/1873-3468.13499] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2019] [Revised: 06/12/2019] [Accepted: 06/12/2019] [Indexed: 12/30/2022]
Affiliation(s)
- Martin Donato
- Department of Biology University of Fribourg Switzerland
| | - Markus Geisler
- Department of Biology University of Fribourg Switzerland
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Corigliano MG, Albarracín RM, Vilas JM, Sánchez López EF, Bengoa Luoni SA, Deng B, Farran I, Veramendi J, Maiale SJ, Sander VA, Clemente M. Heat treatment alleviates the growth and photosynthetic impairment of transplastomic plants expressing Leishmania infantum Hsp83-Toxoplasma gondii SAG1 fusion protein. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2019; 284:117-126. [PMID: 31084864 PMCID: PMC6785835 DOI: 10.1016/j.plantsci.2019.04.011] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/28/2019] [Revised: 03/19/2019] [Accepted: 04/11/2019] [Indexed: 05/17/2023]
Abstract
Previously, we showed that transplastomic tobacco plants expressing the LiHsp83-SAG1 fusion protein displayed a chlorotic phenotype and growth retardation, while plants expressing the SAG1 and GRA4 antigens alone did not. We conducted a comprehensive examination of the metabolic and photosynthetic parameters that could be affecting the normal growth of LiHsp83-SAG1 plants in order to understand the origin of these pleiotropic effects. These plants presented all photosynthetic pigments and parameters related to PSII efficiency significantly diminished. However, the expression of CHLI, RSSU and LHCa/b genes did not show significant differences between LiHsp83-SAG1 and control plants. Total protein, starch, and soluble sugar contents were also greatly reduced in LiHsp83-SAG1 plants. Since Hsp90 s are constitutively expressed at much higher concentrations at high temperatures, we tested if the fitness of LiHsp83-SAG1 over-expressing LiHsp83 would improve after heat treatment. LiHsp83-SAG1 plants showed an important alleviation of their phenotype and an evident recovery of the PSII function. As far as we know, this is the first report where it is demonstrated that a transplastomic line performs much better at higher temperatures. Finally, we detected that LiHsp83-SAG1 protein could be binding to key photosynthesis-related proteins at 37 °C. Our results suggest that the excess of this molecular chaperone could benefit the plant in a possible heat shock and prevent the expected denaturation of proteins. However, the LiHsp83-SAG1 protein content was weakly decreased in heat-treated plants. Therefore, we cannot rule out that the alleviation observed at 37 °C may be partially due to a reduction of the levels of the recombinant protein.
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Affiliation(s)
- Mariana G Corigliano
- Laboratorio de Biotecnología Vegetal, IIB-INTECH, CONICET-UNSAM, Chascomús, Provincia de Buenos Aires, Argentina
| | - Romina M Albarracín
- Laboratorio de Biotecnología Vegetal, IIB-INTECH, CONICET-UNSAM, Chascomús, Provincia de Buenos Aires, Argentina
| | - Juan M Vilas
- Laboratorio de Estrés Abiótico en Plantas, IIB-INTECH, CONICET-UNSAM, Chascomús, Provincia de Buenos Aires, Argentina
| | - Edwin F Sánchez López
- Laboratorio de Biotecnología Vegetal, IIB-INTECH, CONICET-UNSAM, Chascomús, Provincia de Buenos Aires, Argentina
| | - Sofía A Bengoa Luoni
- Laboratorio de Biotecnología Vegetal, IIB-INTECH, CONICET-UNSAM, Chascomús, Provincia de Buenos Aires, Argentina
| | - Bin Deng
- Marsh Life Science Building, Rm 337, University of Vermont Burlington, Vermont, USA
| | - Inmaculada Farran
- Instituto de Agrobiotecnología, Universidad Pública de Navarra-CSIC, Campus de Arrosadía, Pamplona, Spain
| | - Jon Veramendi
- Instituto de Agrobiotecnología, Universidad Pública de Navarra-CSIC, Campus de Arrosadía, Pamplona, Spain
| | - Santiago J Maiale
- Laboratorio de Estrés Abiótico en Plantas, IIB-INTECH, CONICET-UNSAM, Chascomús, Provincia de Buenos Aires, Argentina
| | - Valeria A Sander
- Laboratorio de Biotecnología Vegetal, IIB-INTECH, CONICET-UNSAM, Chascomús, Provincia de Buenos Aires, Argentina
| | - Marina Clemente
- Laboratorio de Biotecnología Vegetal, IIB-INTECH, CONICET-UNSAM, Chascomús, Provincia de Buenos Aires, Argentina.
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de Luna-Valdez LA, Villaseñor-Salmerón CI, Cordoba E, Vera-Estrella R, León-Mejía P, Guevara-García AA. Functional analysis of the Chloroplast GrpE (CGE) proteins from Arabidopsis thaliana. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2019; 139:293-306. [PMID: 30927692 DOI: 10.1016/j.plaphy.2019.03.027] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/08/2018] [Revised: 02/26/2019] [Accepted: 03/17/2019] [Indexed: 05/20/2023]
Abstract
The function of proteins depends on specific partners that regulate protein folding, degradation and protein-protein interactions, such partners are the chaperones and cochaperones. In chloroplasts, proteins belonging to several families of chaperones have been identified: chaperonins (Cpn60s), Hsp90s (Hsp90-5/Hsp90C), Hsp100s (Hsp93/ClpC) and Hsp70s (cpHsc70s). Several lines of evidence have demonstrated that cpHsc70 chaperones are involved in molecular processes like protein import, protein folding and oligomer formation that impact important physiological aspects in plants such as thermotolerance and thylakoid biogenesis. Despite the vast amount of data existing around the function of cpHcp70s chaperones, very little attention has been paid to the roles of DnaJ and GrpE cochaperones in the chloroplast. In this study, we performed a phylogenetic analysis of the chloroplastic GrpE (CGE) proteins from 71 species. Based on their phylogenetic relationships and on a motif enrichment analysis, we propose a classification system for land plants' CGEs, which include two independent groups with specific primary structure traits. Furthermore, using in vivo assays we determined that the two CGEs from A. thaliana (AtCGEs) complement the mutant phenotype displayed by a knockout E. coli strain defective in the bacterial grpE gene. Moreover, we determined in planta that the two AtCGEs are bona fide chloroplastic proteins, which form the essential homodimers needed to establish direct physical interactions with the cpHsc70-1 chaperone. Finally, we found evidence suggesting that AtCGE1 is involved in specific physiological phenomena in A. thaliana, such as the chloroplastic response to heat stress, and the correct oligomerization of the photosynthesis-related LHCII complex.
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Affiliation(s)
- L A de Luna-Valdez
- Departamento de Biología Molecular de Plantas, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Av. Universidad 2001, Col. Chamilpa, Cuernavaca, Morelos, CP 62210, Mexico.
| | - C I Villaseñor-Salmerón
- Departamento de Biología Molecular de Plantas, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Av. Universidad 2001, Col. Chamilpa, Cuernavaca, Morelos, CP 62210, Mexico.
| | - E Cordoba
- Departamento de Biología Molecular de Plantas, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Av. Universidad 2001, Col. Chamilpa, Cuernavaca, Morelos, CP 62210, Mexico.
| | - R Vera-Estrella
- Departamento de Biología Molecular de Plantas, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Av. Universidad 2001, Col. Chamilpa, Cuernavaca, Morelos, CP 62210, Mexico.
| | - P León-Mejía
- Departamento de Biología Molecular de Plantas, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Av. Universidad 2001, Col. Chamilpa, Cuernavaca, Morelos, CP 62210, Mexico.
| | - A A Guevara-García
- Departamento de Biología Molecular de Plantas, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Av. Universidad 2001, Col. Chamilpa, Cuernavaca, Morelos, CP 62210, Mexico.
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Kozeko LY. The Role of HSP90 Chaperones in Stability and Plasticity of Ontogenesis of Plants under Normal and Stressful Conditions (Arabidopsis thaliana). CYTOL GENET+ 2019. [DOI: 10.3103/s0095452719020063] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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46
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Ganesan I, Theg SM. Structural considerations of folded protein import through the chloroplast TOC/TIC translocons. FEBS Lett 2019; 593:565-572. [PMID: 30775779 DOI: 10.1002/1873-3468.13342] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2019] [Revised: 02/13/2019] [Accepted: 02/15/2019] [Indexed: 11/11/2022]
Abstract
Protein import into chloroplasts is carried out by the protein translocons at the outer and inner envelope membranes (TOC and TIC). Detailed structures for these translocons are lacking, with only a low-resolution TOC complex structure available. Recently, we showed that the TOC/TIC translocons can import folded proteins, a rather unique feat for a coupled double membrane system. We also determined the maximum functional TOC/TIC pore size to be 30-35 Å. Here, we discuss how such large pores could form and compare the structural dynamics of the pore-forming Toc75 subunit to its bacterial/mitochondrial Omp85 family homologs. We put forward structural models that can be empirically tested and also briefly review the pore dynamics of other protein translocons with known structures.
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Affiliation(s)
- Iniyan Ganesan
- Department of Plant Biology, University of California Davis, CA, USA
| | - Steven M Theg
- Department of Plant Biology, University of California Davis, CA, USA
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47
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Zhao J, Xu J, Chen B, Cui W, Zhou Z, Song X, Chen Z, Zheng H, Lin L, Peng J, Lu Y, Deng Z, Chen J, Yan F. Characterization of Proteins Involved in Chloroplast Targeting Disturbed by Rice Stripe Virus by Novel Protoplast⁻Chloroplast Proteomics. Int J Mol Sci 2019; 20:E253. [PMID: 30634635 PMCID: PMC6358847 DOI: 10.3390/ijms20020253] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2018] [Revised: 12/19/2018] [Accepted: 01/06/2019] [Indexed: 12/21/2022] Open
Abstract
Rice stripe virus (RSV) is one of the most devastating viral pathogens in rice and can also cause the general chlorosis symptom in Nicotiana benthamiana plants. The chloroplast changes associated with chlorosis symptom suggest that RSV interrupts normal chloroplast functions. Although the change of proteins of the whole cell or inside the chloroplast in response to RSV infection have been revealed by proteomics, the mechanisms resulted in chloroplast-related symptoms and the crucial factors remain to be elucidated. RSV infection caused the malformation of chloroplast structure and a global reduction of chloroplast membrane protein complexes in N. benthamiana plants. Here, both the protoplast proteome and the chloroplast proteome were acquired simultaneously upon RSV infection, and the proteins in each fraction were analyzed. In the protoplasts, 1128 proteins were identified, among which 494 proteins presented significant changes during RSV; meanwhile, 659 proteins were identified from the chloroplasts, and 279 of these chloroplast proteins presented significant change. According to the label-free LC⁻MS/MS data, 66 nucleus-encoded chloroplast-related proteins (ChRPs), which only reduced in chloroplast but not in the whole protoplast, were identified, indicating that these nuclear-encoded ChRPswere not transported to chloroplasts during RSV infection. Gene ontology (GO) enrichment analysis confirmed that RSV infection changed the biological process of protein targeting to chloroplast, where 3 crucial ChRPs (K4CSN4, K4CR23, and K4BXN9) were involved in the regulation of protein targeting into chloroplast. In addition to these 3 proteins, 41 among the 63 candidate proteins were characterized to have chloroplast transit peptides. These results indicated that RSV infection changed the biological process of protein targeting into chloroplast and the location of ChRPs through crucial protein factors, which illuminated a new layer of RSV⁻host interaction that might contribute to the symptom development.
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Affiliation(s)
- Jinping Zhao
- The State Key Laboratory Breeding Base for Sustainable Control of Pest and Disease, Key Laboratory of Biotechnology in Plant Protection of MOA of China and Zhejiang Province, Institute of Virology and Biotechnology, Zhejiang Academy of Agricultural Sciences, Hangzhou 310021, China.
- Texas A&M University AgriLife Research Center at Dallas, Dallas, TX 75252, USA.
| | - Jingjing Xu
- The State Key Laboratory Breeding Base for Sustainable Control of Pest and Disease, Key Laboratory of Biotechnology in Plant Protection of MOA of China and Zhejiang Province, Institute of Virology and Biotechnology, Zhejiang Academy of Agricultural Sciences, Hangzhou 310021, China.
- School of Biotechnology, Jiangnan University, Wuxi 214122, China.
| | - Binghua Chen
- The State Key Laboratory Breeding Base for Sustainable Control of Pest and Disease, Key Laboratory of Biotechnology in Plant Protection of MOA of China and Zhejiang Province, Institute of Virology and Biotechnology, Zhejiang Academy of Agricultural Sciences, Hangzhou 310021, China.
- Institute of Plant Virology, Ningbo University, Ningbo 315211, China.
- Center of Research and Development of Fine Chemicals, Guizhou University, Guiyang 550025, China.
| | - Weijun Cui
- The State Key Laboratory Breeding Base for Sustainable Control of Pest and Disease, Key Laboratory of Biotechnology in Plant Protection of MOA of China and Zhejiang Province, Institute of Virology and Biotechnology, Zhejiang Academy of Agricultural Sciences, Hangzhou 310021, China.
- Institute of Plant Virology, Ningbo University, Ningbo 315211, China.
| | - Zhongjing Zhou
- The State Key Laboratory Breeding Base for Sustainable Control of Pest and Disease, Key Laboratory of Biotechnology in Plant Protection of MOA of China and Zhejiang Province, Institute of Virology and Biotechnology, Zhejiang Academy of Agricultural Sciences, Hangzhou 310021, China.
| | - Xijiao Song
- The State Key Laboratory Breeding Base for Sustainable Control of Pest and Disease, Key Laboratory of Biotechnology in Plant Protection of MOA of China and Zhejiang Province, Institute of Virology and Biotechnology, Zhejiang Academy of Agricultural Sciences, Hangzhou 310021, China.
| | - Zhuo Chen
- The State Key Laboratory Breeding Base for Sustainable Control of Pest and Disease, Key Laboratory of Biotechnology in Plant Protection of MOA of China and Zhejiang Province, Institute of Virology and Biotechnology, Zhejiang Academy of Agricultural Sciences, Hangzhou 310021, China.
- Center of Research and Development of Fine Chemicals, Guizhou University, Guiyang 550025, China.
| | - Hongying Zheng
- The State Key Laboratory Breeding Base for Sustainable Control of Pest and Disease, Key Laboratory of Biotechnology in Plant Protection of MOA of China and Zhejiang Province, Institute of Virology and Biotechnology, Zhejiang Academy of Agricultural Sciences, Hangzhou 310021, China.
- Institute of Plant Virology, Ningbo University, Ningbo 315211, China.
| | - Lin Lin
- The State Key Laboratory Breeding Base for Sustainable Control of Pest and Disease, Key Laboratory of Biotechnology in Plant Protection of MOA of China and Zhejiang Province, Institute of Virology and Biotechnology, Zhejiang Academy of Agricultural Sciences, Hangzhou 310021, China.
- Institute of Plant Virology, Ningbo University, Ningbo 315211, China.
| | - Jiejun Peng
- The State Key Laboratory Breeding Base for Sustainable Control of Pest and Disease, Key Laboratory of Biotechnology in Plant Protection of MOA of China and Zhejiang Province, Institute of Virology and Biotechnology, Zhejiang Academy of Agricultural Sciences, Hangzhou 310021, China.
- Institute of Plant Virology, Ningbo University, Ningbo 315211, China.
| | - Yuwen Lu
- The State Key Laboratory Breeding Base for Sustainable Control of Pest and Disease, Key Laboratory of Biotechnology in Plant Protection of MOA of China and Zhejiang Province, Institute of Virology and Biotechnology, Zhejiang Academy of Agricultural Sciences, Hangzhou 310021, China.
- Institute of Plant Virology, Ningbo University, Ningbo 315211, China.
| | - Zhiping Deng
- The State Key Laboratory Breeding Base for Sustainable Control of Pest and Disease, Key Laboratory of Biotechnology in Plant Protection of MOA of China and Zhejiang Province, Institute of Virology and Biotechnology, Zhejiang Academy of Agricultural Sciences, Hangzhou 310021, China.
| | - Jianping Chen
- The State Key Laboratory Breeding Base for Sustainable Control of Pest and Disease, Key Laboratory of Biotechnology in Plant Protection of MOA of China and Zhejiang Province, Institute of Virology and Biotechnology, Zhejiang Academy of Agricultural Sciences, Hangzhou 310021, China.
- Institute of Plant Virology, Ningbo University, Ningbo 315211, China.
| | - Fei Yan
- The State Key Laboratory Breeding Base for Sustainable Control of Pest and Disease, Key Laboratory of Biotechnology in Plant Protection of MOA of China and Zhejiang Province, Institute of Virology and Biotechnology, Zhejiang Academy of Agricultural Sciences, Hangzhou 310021, China.
- Institute of Plant Virology, Ningbo University, Ningbo 315211, China.
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48
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Bölter B. En route into chloroplasts: preproteins' way home. PHOTOSYNTHESIS RESEARCH 2018; 138:263-275. [PMID: 29943212 DOI: 10.1007/s11120-018-0542-8] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/09/2017] [Accepted: 06/20/2018] [Indexed: 06/08/2023]
Abstract
Chloroplasts are the characteristic endosymbiotic organelles of plant cells which during the course of evolution lost most of their genetic information to the nucleus. Thus, they critically depend on the host cell for allocation of nearly their complete protein supply. This includes gene expression, translation, protein targeting, and transport-all of which need to be tightly regulated and perfectly coordinated to accommodate the cells' needs. To this end, multiple signaling pathways have been implemented that interchange information between the different cellular compartments. One of the most complex and energy consuming processes is the translocation of chloroplast-destined proteins into their target organelle. It is a concerted effort from chaperones, receptor proteins, channels, and regulatory elements to ensure correct targeting, efficient transport, and subsequent folding. Although we have discovered and learned a lot about protein import into chloroplasts in the last decades, there are still many open questions and debates about the roles of individual proteins as well as the mechanistic details. In this review, I will summarize and discuss the published data with a focus on the translocation complex in the chloroplast inner envelope membrane.
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Affiliation(s)
- Bettina Bölter
- Department Biologie I, Botanik, Ludwig-Maximilians-Universität, Planegg-Martinsried, Germany.
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49
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Kikuchi S, Asakura Y, Imai M, Nakahira Y, Kotani Y, Hashiguchi Y, Nakai Y, Takafuji K, Bédard J, Hirabayashi-Ishioka Y, Mori H, Shiina T, Nakai M. A Ycf2-FtsHi Heteromeric AAA-ATPase Complex Is Required for Chloroplast Protein Import. THE PLANT CELL 2018; 30:2677-2703. [PMID: 30309901 PMCID: PMC6305978 DOI: 10.1105/tpc.18.00357] [Citation(s) in RCA: 100] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/07/2018] [Revised: 08/16/2018] [Accepted: 10/01/2018] [Indexed: 05/20/2023]
Abstract
Chloroplasts import thousands of nucleus-encoded preproteins synthesized in the cytosol through the TOC and TIC translocons on the outer and inner envelope membranes, respectively. Preprotein translocation across the inner membrane requires ATP; however, the import motor has remained unclear. Here, we report that a 2-MD heteromeric AAA-ATPase complex associates with the TIC complex and functions as the import motor, directly interacting with various translocating preproteins. This 2-MD complex consists of a protein encoded by the previously enigmatic chloroplast gene ycf2 and five related nuclear-encoded FtsH-like proteins, namely, FtsHi1, FtsHi2, FtsHi4, FtsHi5, and FtsH12. These components are each essential for plant viability and retain the AAA-type ATPase domain, but only FtsH12 contains the zinc binding active site generally conserved among FtsH-type metalloproteases. Furthermore, even the FtsH12 zinc binding site is dispensable for its essential function. Phylogenetic analyses suggest that all AAA-type members of the Ycf2/FtsHi complex including Ycf2 evolved from the chloroplast-encoded membrane-bound AAA-protease FtsH of the ancestral endosymbiont. The Ycf2/FtsHi complex also contains an NAD-malate dehydrogenase, a proposed key enzyme for ATP production in chloroplasts in darkness or in nonphotosynthetic plastids. These findings advance our understanding of this ATP-driven protein translocation system that is unique to the green lineage of photosynthetic eukaryotes.
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Affiliation(s)
- Shingo Kikuchi
- Institute for Protein Research, Osaka University, Osaka 565-0871, Japan
| | - Yukari Asakura
- Institute for Protein Research, Osaka University, Osaka 565-0871, Japan
| | - Midori Imai
- Institute for Protein Research, Osaka University, Osaka 565-0871, Japan
| | - Yoichi Nakahira
- College of Agriculture, Ibaraki University, Ami-cho, Inashiki, Ibaraki 300-0393, Japan
| | - Yoshiko Kotani
- Institute for Protein Research, Osaka University, Osaka 565-0871, Japan
| | - Yasuyuki Hashiguchi
- Department of Biology, Osaka Medical College, Takatsuki, Osaka 569-8686, Japan
| | - Yumi Nakai
- Department of Biochemistry, Osaka Medical College, Takatsuki, Osaka 569-8686, Japan
| | - Kazuaki Takafuji
- CoMIT Omics Center, Graduate School of Medicine, Osaka University, Osaka 565-0871, Japan
| | - Jocelyn Bédard
- Institute for Protein Research, Osaka University, Osaka 565-0871, Japan
| | | | - Hitoshi Mori
- Graduate School of Bioagricultural Sciences, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi 464-8601, Japan
| | - Takashi Shiina
- School of Human Environment Science, Kyoto Prefectural University, Sakyo-ku, Kyoto 606-8522, Japan
| | - Masato Nakai
- Institute for Protein Research, Osaka University, Osaka 565-0871, Japan
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50
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Richardson LGL, Small EL, Inoue H, Schnell DJ. Molecular Topology of the Transit Peptide during Chloroplast Protein Import. THE PLANT CELL 2018; 30:1789-1806. [PMID: 29991536 PMCID: PMC6139696 DOI: 10.1105/tpc.18.00172] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/22/2018] [Revised: 06/26/2018] [Accepted: 07/06/2018] [Indexed: 05/04/2023]
Abstract
Chloroplast protein import is directed by the interaction of the targeting signal (transit peptide) of nucleus-encoded preproteins with translocons at the outer (TOC) and inner (TIC) chloroplast envelope membranes. Studies of the energetics and determinants of transit peptide binding have led to the hypothesis that import occurs through sequential recognition of transit peptides by components of TOC and TIC during protein import. To test this hypothesis, we employed a site-specific cross-linking approach to map transit peptide topology in relation to TOC-TIC components at specific stages of import in Arabidopsis thaliana and pea (Pisum sativum). We demonstrate that the transit peptide is in contact with Tic20 at the inner envelope in addition to TOC complex components at the earliest stages of chloroplast binding. Low levels of ATP hydrolysis catalyze the commitment of the preprotein to import by promoting further penetration across the envelope membranes and stabilizing the association of the preprotein with TOC-TIC. GTP hydrolysis at the TOC receptors serves as a checkpoint to regulate the ATP-dependent commitment of the preprotein to import and is not essential to drive preprotein import. Our results demonstrate the close cooperativity of the TOC and TIC machinery at each stage of transit peptide recognition and membrane translocation during protein import.
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Affiliation(s)
- Lynn G L Richardson
- Department of Plant Biology, Michigan State University, East Lansing, Michigan 48824
| | - Eliana L Small
- Department of Plant Biology, Michigan State University, East Lansing, Michigan 48824
| | - Hitoshi Inoue
- Department of Plant Biology, Michigan State University, East Lansing, Michigan 48824
| | - Danny J Schnell
- Department of Plant Biology, Michigan State University, East Lansing, Michigan 48824
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