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Olasz B, Smithers L, Evans GL, Anandan A, Murcha MW, Vrielink A. Structural analysis of the SAM domain of the Arabidopsis mitochondrial tRNA import receptor. J Biol Chem 2024; 300:107258. [PMID: 38582448 PMCID: PMC11063897 DOI: 10.1016/j.jbc.2024.107258] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2023] [Revised: 03/10/2024] [Accepted: 03/19/2024] [Indexed: 04/08/2024] Open
Abstract
Mitochondria are membrane-bound organelles of endosymbiotic origin with limited protein-coding capacity. The import of nuclear-encoded proteins and nucleic acids is required and essential for maintaining organelle mass, number, and activity. As plant mitochondria do not encode all the necessary tRNA types required, the import of cytosolic tRNA is vital for organelle maintenance. Recently, two mitochondrial outer membrane proteins, named Tric1 and Tric2, for tRNA import component, were shown to be involved in the import of cytosolic tRNA. Tric1/2 binds tRNAalavia conserved residues in the C-terminal Sterile Alpha Motif (SAM) domain. Here we report the X-ray crystal structure of the Tric1 SAM domain. We identified the ability of the SAM domain to form a helical superstructure with six monomers per helical turn and key amino acid residues responsible for its formation. We determined that the oligomerization of the Tric1 SAM domain may play a role in protein function whereby mutation of Gly241 introducing a larger side chain at this position disrupted the oligomer and resulted in the loss of RNA binding capability. Furthermore, complementation of Arabidopsis thaliana Tric1/2 knockout lines with a mutated Tric1 failed to restore the defective plant phenotype. AlphaFold2 structure prediction of both the SAM domain and Tric1 support a cyclic pentameric or hexameric structure. In the case of a hexameric structure, a pore of sufficient dimensions to transfer tRNA across the mitochondrial membrane is observed. Our results highlight the importance of oligomerization of Tric1 for protein function.
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Affiliation(s)
- Bence Olasz
- School of Molecular Sciences, The University of Western Australia, Perth, Western Australia, Australia
| | - Luke Smithers
- School of Molecular Sciences, The University of Western Australia, Perth, Western Australia, Australia
| | - Genevieve L Evans
- School of Molecular Sciences, The University of Western Australia, Perth, Western Australia, Australia
| | - Anandhi Anandan
- School of Molecular Sciences, The University of Western Australia, Perth, Western Australia, Australia
| | - Monika W Murcha
- School of Molecular Sciences, The University of Western Australia, Perth, Western Australia, Australia.
| | - Alice Vrielink
- School of Molecular Sciences, The University of Western Australia, Perth, Western Australia, Australia.
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2
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Höhner R, Day PM, Zimmermann SE, Lopez LS, Krämer M, Giavalisco P, Correa Galvis V, Armbruster U, Schöttler MA, Jahns P, Krueger S, Kunz HH. Stromal NADH supplied by PHOSPHOGLYCERATE DEHYDROGENASE3 is crucial for photosynthetic performance. PLANT PHYSIOLOGY 2021; 186:142-167. [PMID: 33779763 PMCID: PMC8154072 DOI: 10.1093/plphys/kiaa117] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/28/2020] [Accepted: 12/17/2020] [Indexed: 05/22/2023]
Abstract
During photosynthesis, electrons travel from light-excited chlorophyll molecules along the electron transport chain to the final electron acceptor nicotinamide adenine dinucleotide phosphate (NADP) to form NADPH, which fuels the Calvin-Benson-Bassham cycle (CBBC). To allow photosynthetic reactions to occur flawlessly, a constant resupply of the acceptor NADP is mandatory. Several known stromal mechanisms aid in balancing the redox poise, but none of them utilizes the structurally highly similar coenzyme NAD(H). Using Arabidopsis (Arabidopsis thaliana) as a C3-model, we describe a pathway that employs the stromal enzyme PHOSPHOGLYCERATE DEHYDROGENASE 3 (PGDH3). We showed that PGDH3 exerts high NAD(H)-specificity and is active in photosynthesizing chloroplasts. PGDH3 withdrew its substrate 3-PGA directly from the CBBC. As a result, electrons become diverted from NADPH via the CBBC into the separate NADH redox pool. pgdh3 loss-of-function mutants revealed an overreduced NADP(H) redox pool but a more oxidized plastid NAD(H) pool compared to wild-type plants. As a result, photosystem I acceptor side limitation increased in pgdh3. Furthermore, pgdh3 plants displayed delayed CBBC activation, changes in nonphotochemical quenching, and altered proton motive force partitioning. Our fluctuating light-stress phenotyping data showed progressing photosystem II damage in pgdh3 mutants, emphasizing the significance of PGDH3 for plant performance under natural light environments. In summary, this study reveals an NAD(H)-specific mechanism in the stroma that aids in balancing the chloroplast redox poise. Consequently, the stromal NAD(H) pool may provide a promising target to manipulate plant photosynthesis.
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Affiliation(s)
- Ricarda Höhner
- School of Biological Sciences, Washington State University, Pullman, WA 99164-4236, USA
| | - Philip M Day
- School of Biological Sciences, Washington State University, Pullman, WA 99164-4236, USA
| | - Sandra E Zimmermann
- Biocenter University of Cologne, Institute for Plant Science, Cologne 50674, Germany
| | - Laura S Lopez
- School of Biological Sciences, Washington State University, Pullman, WA 99164-4236, USA
| | - Moritz Krämer
- School of Biological Sciences, Washington State University, Pullman, WA 99164-4236, USA
| | | | - Viviana Correa Galvis
- Max Planck Institute of Molecular Plant Physiology, Wissenschaftspark Golm, Potsdam 14476, Germany
| | - Ute Armbruster
- Max Planck Institute of Molecular Plant Physiology, Wissenschaftspark Golm, Potsdam 14476, Germany
| | - Mark Aurel Schöttler
- Max Planck Institute of Molecular Plant Physiology, Wissenschaftspark Golm, Potsdam 14476, Germany
| | - Peter Jahns
- Plant Biochemistry, Heinrich-Heine-University Düsseldorf, Düsseldorf D-40225, Germany
| | - Stephan Krueger
- Biocenter University of Cologne, Institute for Plant Science, Cologne 50674, Germany
| | - Hans-Henning Kunz
- School of Biological Sciences, Washington State University, Pullman, WA 99164-4236, USA
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Yao X, Nie J, Bai R, Sui X. Amino Acid Transporters in Plants: Identification and Function. PLANTS 2020; 9:plants9080972. [PMID: 32751984 PMCID: PMC7466100 DOI: 10.3390/plants9080972] [Citation(s) in RCA: 47] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Revised: 07/25/2020] [Accepted: 07/29/2020] [Indexed: 12/04/2022]
Abstract
Amino acid transporters are the main mediators of nitrogen distribution throughout the plant body, and are essential for sustaining growth and development. In this review, we summarize the current state of knowledge on the identity and biological functions of amino acid transporters in plants, and discuss the regulation of amino acid transporters in response to environmental stimuli. We focus on transporter function in amino acid assimilation and phloem loading and unloading, as well as on the molecular identity of amino acid exporters. Moreover, we discuss the effects of amino acid transport on carbon assimilation, as well as their cross-regulation, which is at the heart of sustainable agricultural production.
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Unal D, García-Caparrós P, Kumar V, Dietz KJ. Chloroplast-associated molecular patterns as concept for fine-tuned operational retrograde signalling. Philos Trans R Soc Lond B Biol Sci 2020; 375:20190443. [PMID: 32362264 DOI: 10.1098/rstb.2019.0443] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Chloroplasts compose about one-quarter of the mesophyll cell volume and contain about 60% of the cell protein. Photosynthetic carbon assimilation is the dominating metabolism in illuminated leaves. To optimize the resource expenditure in these costly organelles and to control and adjust chloroplast metabolism, an intensive transfer of information between nucleus-cytoplasm and chloroplasts occurs in both directions as anterograde and retrograde signalling. Recent research identified multiple retrograde pathways that use metabolite transfer and include reaction products of lipids and carotenoids with reactive oxygen species (ROS). Other pathways use metabolites of carbon, sulfur and nitrogen metabolism, low molecular weight antioxidants and hormone precursors to carry information between the cell compartments. This review focuses on redox- and ROS-related retrograde signalling pathways. In analogy to the microbe-associated molecular pattern, we propose the term 'chloroplast-associated molecular pattern' which connects chloroplast performance to extrachloroplast processes such as nuclear gene transcription, posttranscriptional processing, including translation, and RNA and protein fate. This article is part of the theme issue 'Retrograde signalling from endosymbiotic organelles'.
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Affiliation(s)
- Dilek Unal
- Biochemistry and Physiology of Plants, Bielefeld University, 33501 Bielefeld, Germany.,Molecular Biology and Genetic, Faculty of Science and Letter, Bilecik Seyh Edebali University, 11230 Bilecik, Turkey
| | - Pedro García-Caparrós
- Biochemistry and Physiology of Plants, Bielefeld University, 33501 Bielefeld, Germany.,Department of Agronomy, University of Almeria, Higher Engineering School, Agrifood Campus of International Excellence ceiA3, Carretera de Sacramento s/n, La Cañada de San Urbano 04120, Almeria, Spain
| | - Vijay Kumar
- Biochemistry and Physiology of Plants, Bielefeld University, 33501 Bielefeld, Germany
| | - Karl-Josef Dietz
- Biochemistry and Physiology of Plants, Bielefeld University, 33501 Bielefeld, Germany
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5
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Plant mitochondrial protein import: the ins and outs. Biochem J 2018; 475:2191-2208. [PMID: 30018142 DOI: 10.1042/bcj20170521] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2018] [Revised: 06/19/2018] [Accepted: 06/21/2018] [Indexed: 01/29/2023]
Abstract
The majority of the mitochondrial proteome, required to fulfil its diverse range of functions, is cytosolically synthesised and translocated via specialised machinery. The dedicated translocases, receptors, and associated proteins have been characterised in great detail in yeast over the last several decades, yet many of the mechanisms that regulate these processes in higher eukaryotes are still unknown. In this review, we highlight the current knowledge of mitochondrial protein import in plants. Despite the fact that the mechanisms of mitochondrial protein import have remained conserved across species, many unique features have arisen in plants to encompass the developmental, tissue-specific, and stress-responsive regulation in planta. An understanding of unique features and mechanisms in plants provides us with a unique insight into the regulation of mitochondrial biogenesis in higher eukaryotes.
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Marchand J, Heydarizadeh P, Schoefs B, Spetea C. Ion and metabolite transport in the chloroplast of algae: lessons from land plants. Cell Mol Life Sci 2018; 75:2153-2176. [PMID: 29541792 PMCID: PMC5948301 DOI: 10.1007/s00018-018-2793-0] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2017] [Revised: 03/01/2018] [Accepted: 03/07/2018] [Indexed: 12/28/2022]
Abstract
Chloroplasts are endosymbiotic organelles and play crucial roles in energy supply and metabolism of eukaryotic photosynthetic organisms (algae and land plants). They harbor channels and transporters in the envelope and thylakoid membranes, mediating the exchange of ions and metabolites with the cytosol and the chloroplast stroma and between the different chloroplast subcompartments. In secondarily evolved algae, three or four envelope membranes surround the chloroplast, making more complex the exchange of ions and metabolites. Despite the importance of transport proteins for the optimal functioning of the chloroplast in algae, and that many land plant homologues have been predicted, experimental evidence and molecular characterization are missing in most cases. Here, we provide an overview of the current knowledge about ion and metabolite transport in the chloroplast from algae. The main aspects reviewed are localization and activity of the transport proteins from algae and/or of homologues from other organisms including land plants. Most chloroplast transporters were identified in the green alga Chlamydomonas reinhardtii, reside in the envelope and participate in carbon acquisition and metabolism. Only a few identified algal transporters are located in the thylakoid membrane and play role in ion transport. The presence of genes for putative transporters in green algae, red algae, diatoms, glaucophytes and cryptophytes is discussed, and roles in the chloroplast are suggested. A deep knowledge in this field is required because algae represent a potential source of biomass and valuable metabolites for industry, medicine and agriculture.
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Affiliation(s)
- Justine Marchand
- Metabolism, Bioengineering of Microalgal Molecules and Applications (MIMMA), Mer Molécules Santé, IUML, FR 3473 CNRS, Le Mans University, 72000, Le Mans, France
| | - Parisa Heydarizadeh
- Metabolism, Bioengineering of Microalgal Molecules and Applications (MIMMA), Mer Molécules Santé, IUML, FR 3473 CNRS, Le Mans University, 72000, Le Mans, France
| | - Benoît Schoefs
- Metabolism, Bioengineering of Microalgal Molecules and Applications (MIMMA), Mer Molécules Santé, IUML, FR 3473 CNRS, Le Mans University, 72000, Le Mans, France.
| | - Cornelia Spetea
- Department of Biological and Environmental Sciences, University of Gothenburg, 40530, Göteborg, Sweden.
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Zang X, Geng X, Liu K, Wang F, Liu Z, Zhang L, Zhao Y, Tian X, Hu Z, Yao Y, Ni Z, Xin M, Sun Q, Peng H. Ectopic expression of TaOEP16-2-5B, a wheat plastid outer envelope protein gene, enhances heat and drought stress tolerance in transgenic Arabidopsis plants. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2017; 258:1-11. [PMID: 28330552 DOI: 10.1016/j.plantsci.2017.01.011] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/02/2016] [Revised: 12/15/2016] [Accepted: 01/18/2017] [Indexed: 05/11/2023]
Abstract
Abiotic stresses, such as heat and drought, are major environmental factors restricting crop productivity and quality worldwide. A plastid outer envelope protein gene, TaOEP16-2, was identified from our previous transcriptome analysis [1,2]. In this study, the isolation and functional characterization of the TaOEP16-2 gene was reported. Three homoeologous sequences of TaOEP16-2 were isolated from hexaploid wheat, which were localized on the chromosomes 5A, 5B and 5D, respectively. These three homoeologues exhibited different expression patterns under heat stress conditions, TaOEP16-2-5B was the dominant one, and TaOEP16-2-5B was selected for further analysis. Compared with wild type (WT) plants, transgenic Arabidopsis plants overexpressing the TaOEP16-2-5B gene exhibited enhanced tolerance to heat stress, which was supported by improved survival rate, strengthened cell membrane stability and increased sucrose content. It was also found that TaOEP16-2 was induced by drought stress and involved in drought stress tolerance. TaOEP16-2-5B has the same function in ABA-controlled seed germination as AtOEP16-2. Our results suggest that TaOEP16-2-5B plays an important role in heat and drought stress tolerance, and could be utilized in transgenic breeding of wheat and other crop plants.
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Affiliation(s)
- Xinshan Zang
- State Key Laboratory for Agrobiotechnology, Key Laboratory of Crop Heterosis and Utilization (MOE), Beijing Key Laboratory of Crop Genetic Improvement, China Agricultural University, Beijing, 100193, China
| | - Xiaoli Geng
- State Key Laboratory for Agrobiotechnology, Key Laboratory of Crop Heterosis and Utilization (MOE), Beijing Key Laboratory of Crop Genetic Improvement, China Agricultural University, Beijing, 100193, China
| | - Kelu Liu
- State Key Laboratory for Agrobiotechnology, Key Laboratory of Crop Heterosis and Utilization (MOE), Beijing Key Laboratory of Crop Genetic Improvement, China Agricultural University, Beijing, 100193, China
| | - Fei Wang
- State Key Laboratory for Agrobiotechnology, Key Laboratory of Crop Heterosis and Utilization (MOE), Beijing Key Laboratory of Crop Genetic Improvement, China Agricultural University, Beijing, 100193, China
| | - Zhenshan Liu
- State Key Laboratory for Agrobiotechnology, Key Laboratory of Crop Heterosis and Utilization (MOE), Beijing Key Laboratory of Crop Genetic Improvement, China Agricultural University, Beijing, 100193, China
| | - Liyuan Zhang
- State Key Laboratory for Agrobiotechnology, Key Laboratory of Crop Heterosis and Utilization (MOE), Beijing Key Laboratory of Crop Genetic Improvement, China Agricultural University, Beijing, 100193, China
| | - Yue Zhao
- State Key Laboratory for Agrobiotechnology, Key Laboratory of Crop Heterosis and Utilization (MOE), Beijing Key Laboratory of Crop Genetic Improvement, China Agricultural University, Beijing, 100193, China
| | - Xuejun Tian
- State Key Laboratory for Agrobiotechnology, Key Laboratory of Crop Heterosis and Utilization (MOE), Beijing Key Laboratory of Crop Genetic Improvement, China Agricultural University, Beijing, 100193, China
| | - Zhaorong Hu
- State Key Laboratory for Agrobiotechnology, Key Laboratory of Crop Heterosis and Utilization (MOE), Beijing Key Laboratory of Crop Genetic Improvement, China Agricultural University, Beijing, 100193, China
| | - Yingyin Yao
- State Key Laboratory for Agrobiotechnology, Key Laboratory of Crop Heterosis and Utilization (MOE), Beijing Key Laboratory of Crop Genetic Improvement, China Agricultural University, Beijing, 100193, China
| | - Zhongfu Ni
- State Key Laboratory for Agrobiotechnology, Key Laboratory of Crop Heterosis and Utilization (MOE), Beijing Key Laboratory of Crop Genetic Improvement, China Agricultural University, Beijing, 100193, China
| | - Mingming Xin
- State Key Laboratory for Agrobiotechnology, Key Laboratory of Crop Heterosis and Utilization (MOE), Beijing Key Laboratory of Crop Genetic Improvement, China Agricultural University, Beijing, 100193, China
| | - Qixin Sun
- State Key Laboratory for Agrobiotechnology, Key Laboratory of Crop Heterosis and Utilization (MOE), Beijing Key Laboratory of Crop Genetic Improvement, China Agricultural University, Beijing, 100193, China
| | - Huiru Peng
- State Key Laboratory for Agrobiotechnology, Key Laboratory of Crop Heterosis and Utilization (MOE), Beijing Key Laboratory of Crop Genetic Improvement, China Agricultural University, Beijing, 100193, China.
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Pottosin I, Shabala S. Transport Across Chloroplast Membranes: Optimizing Photosynthesis for Adverse Environmental Conditions. MOLECULAR PLANT 2016; 9:356-370. [PMID: 26597501 DOI: 10.1016/j.molp.2015.10.006] [Citation(s) in RCA: 68] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/27/2015] [Revised: 10/17/2015] [Accepted: 10/19/2015] [Indexed: 05/18/2023]
Abstract
Chloroplasts are central to solar light harvesting and photosynthesis. Optimal chloroplast functioning is vitally dependent on a very intensive traffic of metabolites and ions between the cytosol and stroma, and should be attuned for adverse environmental conditions. This is achieved by an orchestrated regulation of a variety of transport systems located at chloroplast membranes such as porines, solute channels, ion-specific cation and anion channels, and various primary and secondary active transport systems. In this review we describe the molecular nature and functional properties of the inner and outer envelope and thylakoid membrane channels and transporters. We then discuss how their orchestrated regulation affects thylakoid structure, electron transport and excitation energy transfer, proton-motive force partition, ion homeostasis, stromal pH regulation, and volume regulation. We link the activity of key cation and anion transport systems with stress-specific signaling processes in chloroplasts, and discuss how these signals interact with the signals generated in other organelles to optimize the cell performance, with a special emphasis on Ca(2+) and reactive oxygen species signaling.
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Affiliation(s)
- Igor Pottosin
- Biomedical Centre, University of Colima, Colima, Colima 28045, Mexico; School of Land and Food, University of Tasmania, Hobart, TAS 7001, Australia
| | - Sergey Shabala
- School of Land and Food, University of Tasmania, Hobart, TAS 7001, Australia.
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Pottosin I, Dobrovinskaya O. Ion Channels in Native Chloroplast Membranes: Challenges and Potential for Direct Patch-Clamp Studies. Front Physiol 2015; 6:396. [PMID: 26733887 PMCID: PMC4686732 DOI: 10.3389/fphys.2015.00396] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2015] [Accepted: 12/04/2015] [Indexed: 11/29/2022] Open
Abstract
Photosynthesis without any doubt depends on the activity of the chloroplast ion channels. The thylakoid ion channels participate in the fine partitioning of the light-generated proton-motive force (p.m.f.). By regulating, therefore, luminal pH, they affect the linear electron flow and non-photochemical quenching. Stromal ion homeostasis and signaling, on the other hand, depend on the activity of both thylakoid and envelope ion channels. Experimentally, intact chloroplasts and swollen thylakoids were proven to be suitable for direct measurements of the ion channels activity via conventional patch-clamp technique; yet, such studies became infrequent, although their potential is far from being exhausted. In this paper we wish to summarize existing challenges for direct patch-clamping of native chloroplast membranes as well as present available results on the activity of thylakoid Cl− (ClC?) and divalent cation-permeable channels, along with their tentative roles in the p.m.f. partitioning, volume regulation, and stromal Ca2+ and Mg2+ dynamics. Patch-clamping of the intact envelope revealed both large-conductance porin-like channels, likely located in the outer envelope membrane and smaller conductance channels, more compatible with the inner envelope location. Possible equivalent model for the sandwich-like arrangement of the two envelope membranes within the patch electrode will be discussed, along with peculiar properties of the fast-activated cation channel in the context of the stromal pH control.
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Affiliation(s)
- Igor Pottosin
- Centro Universitario de Investigaciones Biomédicas, Universidad de Colima Colima, Mexico
| | - Oxana Dobrovinskaya
- Centro Universitario de Investigaciones Biomédicas, Universidad de Colima Colima, Mexico
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Identification of a plastidial phenylalanine exporter that influences flux distribution through the phenylalanine biosynthetic network. Nat Commun 2015; 6:8142. [PMID: 26356302 PMCID: PMC4647861 DOI: 10.1038/ncomms9142] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2015] [Accepted: 07/22/2015] [Indexed: 12/19/2022] Open
Abstract
In addition to proteins, L-phenylalanine is a versatile precursor for thousands of plant metabolites. Production of phenylalanine-derived compounds is a complex multi-compartmental process using phenylalanine synthesized predominantly in plastids as precursor. The transporter(s) exporting phenylalanine from plastids, however, remains unknown. Here, a gene encoding a Petunia hybrida plastidial cationic amino-acid transporter (PhpCAT) functioning in plastidial phenylalanine export is identified based on homology to an Escherichia coli phenylalanine transporter and co-expression with phenylalanine metabolic genes. Radiolabel transport assays show that PhpCAT exports all three aromatic amino acids. PhpCAT downregulation and overexpression result in decreased and increased levels, respectively, of phenylalanine-derived volatiles, as well as phenylalanine, tyrosine and their biosynthetic intermediates. Metabolic flux analysis reveals that flux through the plastidial phenylalanine biosynthetic pathway is reduced in PhpCAT RNAi lines, suggesting that the rate of phenylalanine export from plastids contributes to regulating flux through the aromatic amino-acid network.
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Winter G, Todd CD, Trovato M, Forlani G, Funck D. Physiological implications of arginine metabolism in plants. FRONTIERS IN PLANT SCIENCE 2015; 6:534. [PMID: 26284079 PMCID: PMC4520006 DOI: 10.3389/fpls.2015.00534] [Citation(s) in RCA: 273] [Impact Index Per Article: 30.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/30/2015] [Accepted: 06/29/2015] [Indexed: 05/18/2023]
Abstract
Nitrogen is a limiting resource for plant growth in most terrestrial habitats since large amounts of nitrogen are needed to synthesize nucleic acids and proteins. Among the 21 proteinogenic amino acids, arginine has the highest nitrogen to carbon ratio, which makes it especially suitable as a storage form of organic nitrogen. Synthesis in chloroplasts via ornithine is apparently the only operational pathway to provide arginine in plants, and the rate of arginine synthesis is tightly regulated by various feedback mechanisms in accordance with the overall nutritional status. While several steps of arginine biosynthesis still remain poorly characterized in plants, much wider attention has been paid to inter- and intracellular arginine transport as well as arginine-derived metabolites. A role of arginine as alternative source besides glutamate for proline biosynthesis is still discussed controversially and may be prevented by differential subcellular localization of enzymes. Apparently, arginine is a precursor for nitric oxide (NO), although the molecular mechanism of NO production from arginine remains unclear in higher plants. In contrast, conversion of arginine to polyamines is well documented, and in several plant species also ornithine can serve as a precursor for polyamines. Both NO and polyamines play crucial roles in regulating developmental processes as well as responses to biotic and abiotic stress. It is thus conceivable that arginine catabolism serves on the one hand to mobilize nitrogen storages, while on the other hand it may be used to fine-tune development and defense mechanisms against stress. This review summarizes the recent advances in our knowledge about arginine metabolism, with a special focus on the model plant Arabidopsis thaliana, and pinpoints still unresolved critical questions.
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Affiliation(s)
- Gudrun Winter
- Laboratory of Plant Physiology and Biochemistry, Department of Biology, University of Konstanz, Konstanz, Germany
| | | | - Maurizio Trovato
- Department of Biology and Biotechnology, Sapienza University of Rome, Rome, Italy
| | - Giuseppe Forlani
- Laboratory of Plant Physiology and Biochemistry, Department of Life Science and Biotechnology, University of Ferrara, Ferrara, Italy
| | - Dietmar Funck
- Laboratory of Plant Physiology and Biochemistry, Department of Biology, University of Konstanz, Konstanz, Germany
- *Correspondence: Dietmar Funck, Laboratory of Plant Physiology and Biochemistry, Department of Biology, University of Konstanz, Universitätsstraße 10, 78457 Konstanz, Germany,
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Gutierrez-Carbonell E, Takahashi D, Lattanzio G, Rodríguez-Celma J, Kehr J, Soll J, Philippar K, Uemura M, Abadía J, López-Millán AF. The distinct functional roles of the inner and outer chloroplast envelope of Pea (Pisum sativum) as revealed by proteomic approaches. J Proteome Res 2014; 13:2941-53. [PMID: 24792535 DOI: 10.1021/pr500106s] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Protein profiles of inner (IE) and outer (OE) chloroplast envelope membrane preparations from pea were studied using shotgun nLC-MS/MS and two-dimensional electrophoresis, and 589 protein species (NCBI entries) were identified. The relative enrichment of each protein in the IE/OE pair of membranes was used to provide an integrated picture of the chloroplast envelope. From the 546 proteins identified with shotgun, 321 showed a significant differential distribution, with 180 being enriched in IE and 141 in OE. To avoid redundancy and facilitate in silico localization, Arabidopsis homologues were used to obtain a nonredundant list of 409 envelope proteins, with many showing significant OE or IE enrichment. Functional classification reveals that IE is a selective barrier for transport of many metabolites and plays a major role in controlling protein homeostasis, whereas proteins in OE are more heterogeneous and participate in a wide range of processes. Data support that metabolic processes previously described to occur in the envelope such as chlorophyll and tocopherol biosynthesis can be ascribed to the IE, whereas others such as carotenoid or lipid biosynthesis occur in both membranes. Furthermore, results allow empirical assignation to the IE and/or OE of many proteins previously assigned to the bulk chloroplast envelope proteome.
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Affiliation(s)
- Elain Gutierrez-Carbonell
- Plant Nutrition Department, Aula Dei Experimental Station, CSIC , P.O. Box 13034, 50080 Zaragoza, Spain
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Murcha MW, Kubiszewski-Jakubiak S, Wang Y, Whelan J. Evidence for interactions between the mitochondrial import apparatus and respiratory chain complexes via Tim21-like proteins in Arabidopsis. FRONTIERS IN PLANT SCIENCE 2014; 5:82. [PMID: 24653731 PMCID: PMC3949100 DOI: 10.3389/fpls.2014.00082] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/04/2014] [Accepted: 02/21/2014] [Indexed: 05/06/2023]
Abstract
The mitochondrial import machinery and the respiratory chain complexes of the inner membrane are highly interdependent for the efficient import and assembly of nuclear encoded respiratory chain components and for the generation of a proton motive force essential for protein translocation into or across the inner membrane. In plant and non-plant systems functional, physical, and evolutionary associations have been observed between proteins of the respiratory chain and protein import apparatus. Here we identify two novel Tim21-like proteins encoded by At2g40800 and At3g56430 that are imported into the mitochondrial inner membrane. We propose that Tim21-like proteins may associate with respiratory chain Complex I, III, in addition to the TIM17:23 translocase of the inner membrane. These results are discussed further with regards to the regulation of mitochondrial activity and biogenesis.
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Affiliation(s)
- Monika W. Murcha
- ARC Centre of Excellence in Plant Energy Biology, The University of Western AustraliaPerth, WA, Australia
- *Correspondence: Monika W. Murcha, ARC Centre of Excellence in Plant Energy Biology, University of Western Australia, MCS Building M316, 35 Stirling Highway, Crawley, Perth, WA 6009, Australia e-mail:
| | | | - Yan Wang
- ARC Centre of Excellence in Plant Energy Biology, The University of Western AustraliaPerth, WA, Australia
| | - James Whelan
- Department of Botany, ARC Centre of Excellence in Plant Energy Biology, School of Life Sciences, La Trobe UniversityBundoora, VIC, Australia
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Rolland N, Curien G, Finazzi G, Kuntz M, Maréchal E, Matringe M, Ravanel S, Seigneurin-Berny D. The Biosynthetic Capacities of the Plastids and Integration Between Cytoplasmic and Chloroplast Processes. Annu Rev Genet 2012; 46:233-64. [DOI: 10.1146/annurev-genet-110410-132544] [Citation(s) in RCA: 82] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Norbert Rolland
- Laboratoire de Physiologie Cellulaire et Végétale, CNRS/Université Joseph Fourier Grenoble I/INRA/CEA, 38054 Grenoble Cedex 9, France; , , , , , , ,
| | - Gilles Curien
- Laboratoire de Physiologie Cellulaire et Végétale, CNRS/Université Joseph Fourier Grenoble I/INRA/CEA, 38054 Grenoble Cedex 9, France; , , , , , , ,
| | - Giovanni Finazzi
- Laboratoire de Physiologie Cellulaire et Végétale, CNRS/Université Joseph Fourier Grenoble I/INRA/CEA, 38054 Grenoble Cedex 9, France; , , , , , , ,
| | - Marcel Kuntz
- Laboratoire de Physiologie Cellulaire et Végétale, CNRS/Université Joseph Fourier Grenoble I/INRA/CEA, 38054 Grenoble Cedex 9, France; , , , , , , ,
| | - Eric Maréchal
- Laboratoire de Physiologie Cellulaire et Végétale, CNRS/Université Joseph Fourier Grenoble I/INRA/CEA, 38054 Grenoble Cedex 9, France; , , , , , , ,
| | - Michel Matringe
- Laboratoire de Physiologie Cellulaire et Végétale, CNRS/Université Joseph Fourier Grenoble I/INRA/CEA, 38054 Grenoble Cedex 9, France; , , , , , , ,
| | - Stéphane Ravanel
- Laboratoire de Physiologie Cellulaire et Végétale, CNRS/Université Joseph Fourier Grenoble I/INRA/CEA, 38054 Grenoble Cedex 9, France; , , , , , , ,
| | - Daphné Seigneurin-Berny
- Laboratoire de Physiologie Cellulaire et Végétale, CNRS/Université Joseph Fourier Grenoble I/INRA/CEA, 38054 Grenoble Cedex 9, France; , , , , , , ,
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15
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Tan YF, Millar AH, Taylor NL. Components of mitochondrial oxidative phosphorylation vary in abundance following exposure to cold and chemical stresses. J Proteome Res 2012; 11:3860-79. [PMID: 22574745 DOI: 10.1021/pr3003535] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Plant mitochondria are highly responsive organelles that vary their metabolism in response to a wide range of chemical and environmental conditions. Quantitative proteomics studies have begun to allow the analysis of these large-scale protein changes in mitochondria. However studies of the integral membrane proteome of plant mitochondria, arguably the site responsible for the most fundamental mitochondrial processes of oxidative phosphorylation, protein import and metabolite transport, remain a technical challenge. Here we have investigated the changes in protein abundance in response to a number of chemical stresses and cold. In addition to refining the subcellular localization of 66 proteins, we have been able to characterize 596 protein × treatment combinations following a range of stresses. To date it has been assumed that the main mitochondrial response to stress involved the induction of alternative respiratory proteins such as AOX, UCPs, and alternative NAD(P)H dehydrogenases; we now provide evidence for a number of very specific protein abundance changes that have not been highlighted previously by transcript studies. This includes both previously characterized stress responsive proteins as well as major components of oxidative phosphorylation, protein import/export, and metabolite transport.
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Affiliation(s)
- Yew-Foon Tan
- ARC Centre of Excellence in Plant Energy Biology, MCS Building M316, The University of Western Australia, 35 Stirling Highway, Crawley WA 6009, Western Australia, Australia
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16
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Pudelski B, Schock A, Hoth S, Radchuk R, Weber H, Hofmann J, Sonnewald U, Soll J, Philippar K. The plastid outer envelope protein OEP16 affects metabolic fluxes during ABA-controlled seed development and germination. JOURNAL OF EXPERIMENTAL BOTANY 2012; 63:1919-36. [PMID: 22155670 PMCID: PMC3295387 DOI: 10.1093/jxb/err375] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/15/2011] [Revised: 10/15/2011] [Accepted: 10/21/2011] [Indexed: 05/20/2023]
Abstract
Previously, the OEP16.1 channel pore in the outer envelope membrane of mature pea (Pisum sativum) chloroplasts in vitro has been characterized to be selective for amino acids. Isolation of OEP16.2, a second OEP16 isoform from pea, in the current study allowed membrane localization and gene expression of OEP16 to be followed throughout seed development and germination of Arabidopsis thaliana and P. sativum. Thereby it can be shown on the transcript and protein level that the isoforms OEP16.1 and OEP16.2 in both plant species are alternating: whereas OEP16.1 is prominent in early embryo development and first leaves of the growing plantlet, OEP16.2 dominates in late seed development stages, which are associated with dormancy and desiccation, as well as early germination events. Further, OEP16.2 expression in seeds is under control of the phytohormone abscisic acid (ABA), leading to an ABA-hypersensitive phenotype of germinating oep16 knockout mutants. In consequence, the loss of OEP16 causes metabolic imbalance, in particular that of amino acids during seed development and early germination. It is thus concluded that in vivo OEP16 most probably functions in shuttling amino acids across the outer envelope of seed plastids.
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Affiliation(s)
- Birgit Pudelski
- Biochemie und Physiologie der Pflanzen, Department Biologie I, Botanik, Ludwig-Maximilians-Universität München, D-82152 Planegg-Martinsried, Germany
- Munich Centre for Integrated Protein Science CiPSM, Ludwig-Maximilians-Universität München, D-81377 München, Germany
| | - Annette Schock
- Biochemie und Physiologie der Pflanzen, Department Biologie I, Botanik, Ludwig-Maximilians-Universität München, D-82152 Planegg-Martinsried, Germany
- Munich Centre for Integrated Protein Science CiPSM, Ludwig-Maximilians-Universität München, D-81377 München, Germany
| | - Stefan Hoth
- Molekulare Pflanzenphysiologie, Department Biologie, Friedrich-Alexander-Universität Erlangen-Nürnberg, Staudtstrasse 5, D-91058 Erlangen, Germany
- Pflanzenphysiologie, Biozentrum Klein Flottbek, Universität Hamburg, Ohnhorststrabe 18, D-22609 Hamburg, Germany
| | - Ruslana Radchuk
- Leibniz-Institut für Pflanzengenetik und Kulturpflanzenforschung (IPK), Corrensstrasse 3, D-06466 Gatersleben, Germany
| | - Hans Weber
- Leibniz-Institut für Pflanzengenetik und Kulturpflanzenforschung (IPK), Corrensstrasse 3, D-06466 Gatersleben, Germany
| | - Jörg Hofmann
- Biochemie, Department Biologie, Friedrich-Alexander-Universität Erlangen-Nürnberg, Staudtstrasse 5, D-91058 Erlangen, Germany
| | - Uwe Sonnewald
- Biochemie, Department Biologie, Friedrich-Alexander-Universität Erlangen-Nürnberg, Staudtstrasse 5, D-91058 Erlangen, Germany
| | - Jürgen Soll
- Biochemie und Physiologie der Pflanzen, Department Biologie I, Botanik, Ludwig-Maximilians-Universität München, D-82152 Planegg-Martinsried, Germany
- Munich Centre for Integrated Protein Science CiPSM, Ludwig-Maximilians-Universität München, D-81377 München, Germany
| | - Katrin Philippar
- Biochemie und Physiologie der Pflanzen, Department Biologie I, Botanik, Ludwig-Maximilians-Universität München, D-82152 Planegg-Martinsried, Germany
- Munich Centre for Integrated Protein Science CiPSM, Ludwig-Maximilians-Universität München, D-81377 München, Germany
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17
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Okumoto S, Pilot G. Amino acid export in plants: a missing link in nitrogen cycling. MOLECULAR PLANT 2011; 4:453-63. [PMID: 21324969 PMCID: PMC3143828 DOI: 10.1093/mp/ssr003] [Citation(s) in RCA: 107] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/11/2010] [Accepted: 12/24/2010] [Indexed: 05/17/2023]
Abstract
The export of nutrients from source organs to parts of the body where they are required (e.g. sink organs) is a fundamental biological process. Export of amino acids, one of the most abundant nitrogen species in plant long-distance transport tissues (i.e. xylem and phloem), is an essential process for the proper distribution of nitrogen in the plant. Physiological studies have detected the presence of multiple amino acid export systems in plant cell membranes. Yet, surprisingly little is known about the molecular identity of amino acid exporters, partially due to the technical difficulties hampering the identification of exporter proteins. In this short review, we will summarize our current knowledge about amino acid export systems in plants. Several studies have described plant amino acid transporters capable of bi-directional, facilitative transport, reminiscent of activities identified by earlier physiological studies. Moreover, recent expansion in the number of available amino acid transporter sequences have revealed evolutionary relationships between amino acid exporters from other organisms with a number of uncharacterized plant proteins, some of which might also function as amino acid exporters. In addition, genes that may regulate export of amino acids have been discovered. Studies of these putative transporter and regulator proteins may help in understanding the elusive molecular mechanisms of amino acid export in plants.
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Affiliation(s)
- Sakiko Okumoto
- 549 Latham Hall, Virginia Tech, Blacksburg, VA 24061, USA.
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18
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Breuers FKH, Bräutigam A, Weber APM. The Plastid Outer Envelope - A Highly Dynamic Interface between Plastid and Cytoplasm. FRONTIERS IN PLANT SCIENCE 2011; 2:97. [PMID: 22629266 PMCID: PMC3355566 DOI: 10.3389/fpls.2011.00097] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/24/2011] [Accepted: 11/29/2011] [Indexed: 05/09/2023]
Abstract
Plastids are the defining organelles of all photosynthetic eukaryotes. They are the site of photosynthesis and of a large number of other essential metabolic pathways, such as fatty acid and amino acid biosyntheses, sulfur and nitrogen assimilation, and aromatic and terpenoid compound production, to mention only a few examples. The metabolism of plastids is heavily intertwined and connected with that of the surrounding cytosol, thus causing massive traffic of metabolic precursors, intermediates, and products. Two layers of biological membranes that are called the inner (IE) and the outer (OE) plastid envelope membranes bound the plastids of Archaeplastida. While the IE is generally accepted as the osmo-regulatory barrier between cytosol and stroma, the OE was considered to represent an unspecific molecular sieve, permeable for molecules of up to 10 kDa. However, after the discovery of small substrate specific pores in the OE, this view has come under scrutiny. In addition to controlling metabolic fluxes between plastid and cytosol, the OE is also crucial for protein import into the chloroplast. It contains the receptors and translocation channel of the TOC complex that is required for the canonical post-translational import of nuclear-encoded, plastid-targeted proteins. Further, the OE is a metabolically active compartment of the chloroplast, being involved in, e.g., fatty acid metabolism and membrane lipid production. Also, recent findings hint on the OE as a defense platform against several biotic and abiotic stress conditions, such as cold acclimation, freezing tolerance, and phosphate deprivation. Moreover, dynamic non-covalent interactions between the OE and the endomembrane system are thought to play important roles in lipid and non-canonical protein trafficking between plastid and endoplasmic reticulum. While proteomics and bioinformatics has provided us with comprehensive but still incomplete information on proteins localized in the plastid IE, the stroma, and the thylakoids, our knowledge of the protein composition of the plastid OE is far from complete. In this article, we report on the recent progress in discovering novel OE proteins to draw a conclusive picture of the OE. A "parts list" of the plastid OE will be presented, using data generated by proteomics of plastids isolated from various plant sources.
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Affiliation(s)
| | - Andrea Bräutigam
- Institut für Biochemie der Pflanzen, Heinrich-Heine Universität DüsseldorfDüsseldorf, Germany
| | - Andreas P. M. Weber
- Institut für Biochemie der Pflanzen, Heinrich-Heine Universität DüsseldorfDüsseldorf, Germany
- *Correspondence: Andreas P. M. Weber, Institut für Biochemie der Pflanzen, Heinrich-Heine Universität Düsseldorf, Universitätstrasse 1, D-40225 Düsseldorf, Germany. e-mail:
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Sauer N, Hedrich R. Dynamics and regulation of plant membrane transport. PLANT BIOLOGY (STUTTGART, GERMANY) 2010; 12 Suppl 1:1-2. [PMID: 20712615 DOI: 10.1111/j.1438-8677.2010.00390.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
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