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Meyer EH, Letts JA, Maldonado M. Structural insights into the assembly and the function of the plant oxidative phosphorylation system. THE NEW PHYTOLOGIST 2022; 235:1315-1329. [PMID: 35588181 DOI: 10.1111/nph.18259] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/14/2022] [Accepted: 05/05/2022] [Indexed: 05/23/2023]
Abstract
One of the key functions of mitochondria is the production of ATP to support cellular metabolism and growth. The last step of mitochondrial ATP synthesis is performed by the oxidative phosphorylation (OXPHOS) system, an ensemble of protein complexes embedded in the inner mitochondrial membrane. In the last 25 yr, many structures of OXPHOS complexes and supercomplexes have been resolved in yeast, mammals, and bacteria. However, structures of plant OXPHOS enzymes only became available very recently. In this review, we highlight the plant-specific features revealed by the recent structures and discuss how they advance our understanding of the function and assembly of plant OXPHOS complexes. We also propose new hypotheses to be tested and discuss older findings to be re-evaluated. Further biochemical and structural work on the plant OXPHOS system will lead to a deeper understanding of plant respiration and its regulation, with significant agricultural, environmental, and societal implications.
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Affiliation(s)
- Etienne H Meyer
- Institute of Plant Physiology, Martin-Luther-University Halle-Wittenberg, Weinbergweg 10, 06120, Halle (Saale), Germany
| | - James A Letts
- Department of Molecular and Cellular Biology, University of California-Davis, One Shields Avenue, Davis, CA, 95616, USA
| | - Maria Maldonado
- Department of Molecular and Cellular Biology, University of California-Davis, One Shields Avenue, Davis, CA, 95616, USA
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2
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Huber CV, Jakobs BD, Mishra LS, Niedermaier S, Stift M, Winter G, Adamska I, Funk C, Huesgen PF, Funck D. DEG10 contributes to mitochondrial proteostasis, root growth, and seed yield in Arabidopsis. JOURNAL OF EXPERIMENTAL BOTANY 2019; 70:5423-5436. [PMID: 31225599 PMCID: PMC6793672 DOI: 10.1093/jxb/erz294] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/27/2018] [Accepted: 06/11/2019] [Indexed: 05/04/2023]
Abstract
Maintaining mitochondrial proteome integrity is especially important under stress conditions to ensure a continued ATP supply for protection and adaptation responses in plants. Deg/HtrA proteases are important factors in the cellular protein quality control system, but little is known about their function in mitochondria. Here we analyzed the expression pattern and physiological function of Arabidopsis thaliana DEG10, which has homologs in all photosynthetic eukaryotes. Both expression of DEG10:GFP fusion proteins and immunoblotting after cell fractionation showed an unambiguous subcellular localization exclusively in mitochondria. DEG10 promoter:GUS fusion constructs showed that DEG10 is expressed in trichomes but also in the vascular tissue of roots and aboveground organs. DEG10 loss-of-function mutants were impaired in root elongation, especially at elevated temperature. Quantitative proteome analysis revealed concomitant changes in the abundance of mitochondrial respiratory chain components and assembly factors, which partially appeared to depend on altered mitochondrial retrograde signaling. Under field conditions, lack of DEG10 caused a decrease in seed production. Taken together, our findings demonstrate that DEG10 affects mitochondrial proteostasis, is required for optimal root development and seed set under challenging environmental conditions, and thus contributes to stress tolerance of plants.
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Affiliation(s)
- Catharina V Huber
- Department of Biology, University of Konstanz, Universitätsstraße, Konstanz, Germany
| | - Barbara D Jakobs
- Department of Biology, University of Konstanz, Universitätsstraße, Konstanz, Germany
| | - Laxmi S Mishra
- Department of Chemistry, Umeå University, Linnaeus väg, Umeå, Sweden
| | - Stefan Niedermaier
- Central Institute for Engineering, Electronics and Analytics, ZEA-3 Analytics, Forschungszentrum Jülich, Wilhelm-Johnen-Straße, Jülich, Germany
| | - Marc Stift
- Department of Biology, University of Konstanz, Universitätsstraße, Konstanz, Germany
| | - Gudrun Winter
- Department of Biology, University of Konstanz, Universitätsstraße, Konstanz, Germany
| | - Iwona Adamska
- Department of Biology, University of Konstanz, Universitätsstraße, Konstanz, Germany
| | - Christiane Funk
- Department of Chemistry, Umeå University, Linnaeus väg, Umeå, Sweden
| | - Pitter F Huesgen
- Central Institute for Engineering, Electronics and Analytics, ZEA-3 Analytics, Forschungszentrum Jülich, Wilhelm-Johnen-Straße, Jülich, Germany
- Medical Faculty and University Hospital, Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Cologne, Germany
| | - Dietmar Funck
- Department of Biology, University of Konstanz, Universitätsstraße, Konstanz, Germany
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3
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Matz JM, Goosmann C, Matuschewski K, Kooij TWA. An Unusual Prohibitin Regulates Malaria Parasite Mitochondrial Membrane Potential. Cell Rep 2019; 23:756-767. [PMID: 29669282 DOI: 10.1016/j.celrep.2018.03.088] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2017] [Revised: 02/16/2018] [Accepted: 03/20/2018] [Indexed: 11/26/2022] Open
Abstract
Proteins of the stomatin/prohibitin/flotillin/HfIK/C (SPFH) family are membrane-anchored and perform diverse cellular functions in different organelles. Here, we investigate the SPFH proteins of the murine malaria model parasite Plasmodium berghei, the conserved prohibitin 1, prohibitin 2, and stomatin-like protein and an unusual prohibitin-like protein (PHBL). The SPFH proteins localize to the parasite mitochondrion. While the conserved family members could not be deleted from the Plasmodium genome, PHBL was successfully ablated, resulting in impaired parasite fitness and attenuated virulence in the mammalian host. Strikingly, PHBL-deficient parasites fail to colonize the Anopheles vector because of complete arrest during ookinete development in vivo. We show that this arrest correlates with depolarization of the mitochondrial membrane potential (ΔΨmt). Our results underline the importance of SPFH proteins in the regulation of core mitochondrial functions and suggest that fine-tuning of ΔΨmt in malarial parasites is critical for colonization of the definitive host.
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Affiliation(s)
- Joachim Michael Matz
- Department of Molecular Parasitology, Institute of Biology, Humboldt University, Philippstraße 13, 10115 Berlin, Germany; Parasitology Unit, Max Planck Institute for Infection Biology, Charitéplatz 1, 10117 Berlin, Germany; Department of Medical Microbiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, PO Box 9101, 6500 HB Nijmegen, the Netherlands.
| | - Christian Goosmann
- Microscopy Core Facility, Max Planck Institute for Infection Biology, Charitéplatz 1, 10117 Berlin, Germany
| | - Kai Matuschewski
- Department of Molecular Parasitology, Institute of Biology, Humboldt University, Philippstraße 13, 10115 Berlin, Germany; Parasitology Unit, Max Planck Institute for Infection Biology, Charitéplatz 1, 10117 Berlin, Germany
| | - Taco Wilhelmus Antonius Kooij
- Department of Medical Microbiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, PO Box 9101, 6500 HB Nijmegen, the Netherlands; Center for Molecular and Biomolecular Informatics and Radboud Center for Mitochondrial Medicine, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, PO Box 9101, 6500 HB Nijmegen, the Netherlands.
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4
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Ling Q, Broad W, Trösch R, Töpel M, Demiral Sert T, Lymperopoulos P, Baldwin A, Jarvis RP. Ubiquitin-dependent chloroplast-associated protein degradation in plants. Science 2019; 363:363/6429/eaav4467. [PMID: 30792274 DOI: 10.1126/science.aav4467] [Citation(s) in RCA: 85] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2018] [Accepted: 01/15/2019] [Indexed: 12/11/2022]
Abstract
Chloroplasts contain thousands of nucleus-encoded proteins that are imported from the cytosol by translocases in the chloroplast envelope membranes. Proteolytic regulation of the translocases is critically important, but little is known about the underlying mechanisms. We applied forward genetics and proteomics in Arabidopsis to identify factors required for chloroplast outer envelope membrane (OEM) protein degradation. We identified SP2, an Omp85-type β-barrel channel of the OEM, and CDC48, a cytosolic AAA+ (ATPase associated with diverse cellular activities) chaperone. Both proteins acted in the same pathway as the ubiquitin E3 ligase SP1, which regulates OEM translocase components. SP2 and CDC48 cooperated to bring about retrotranslocation of ubiquitinated substrates from the OEM (fulfilling conductance and motor functions, respectively), enabling degradation of the substrates by the 26S proteasome in the cytosol. Such chloroplast-associated protein degradation (CHLORAD) is vital for organellar functions and plant development.
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Affiliation(s)
- Qihua Ling
- Department of Plant Sciences, University of Oxford, Oxford OX1 3RB, UK
| | - William Broad
- Department of Plant Sciences, University of Oxford, Oxford OX1 3RB, UK
| | - Raphael Trösch
- Department of Biology, University of Leicester, Leicester LE1 7RH, UK
| | - Mats Töpel
- Department of Biology, University of Leicester, Leicester LE1 7RH, UK
| | | | | | - Amy Baldwin
- Department of Biology, University of Leicester, Leicester LE1 7RH, UK
| | - R Paul Jarvis
- Department of Plant Sciences, University of Oxford, Oxford OX1 3RB, UK. .,Department of Biology, University of Leicester, Leicester LE1 7RH, UK
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5
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Rugen N, Straube H, Franken LE, Braun HP, Eubel H. Complexome Profiling Reveals Association of PPR Proteins with Ribosomes in the Mitochondria of Plants. Mol Cell Proteomics 2019; 18:1345-1362. [PMID: 31023727 PMCID: PMC6601216 DOI: 10.1074/mcp.ra119.001396] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2019] [Revised: 04/12/2019] [Indexed: 12/28/2022] Open
Abstract
Mitochondrial transcripts are subject to a wealth of processing mechanisms including cis- and trans-splicing events, as well as base modifications (RNA editing). Hundreds of proteins are required for these processes in plant mitochondria, many of which belong to the pentatricopeptide repeat (PPR) protein superfamily. The structure, localization, and function of these proteins is only poorly understood. Here we present evidence that several PPR proteins are bound to mitoribosomes in plants. A novel complexome profiling strategy in combination with chemical crosslinking has been employed to systematically define the protein constituents of the large and the small ribosomal subunits in the mitochondria of plants. We identified more than 80 ribosomal proteins, which include several PPR proteins and other non-conventional ribosomal proteins. These findings reveal a potential coupling of transcriptional and translational events in the mitochondria of plants. Furthermore, the data indicate an extremely high molecular mass of the "small" subunit, even exceeding that of the "large" subunit.
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Affiliation(s)
- Nils Rugen
- From the ‡Leibniz Universität Hannover, Institute of Plant Genetics, Herrenhäuser Str. 2, 30419 Hannover, Germany
| | - Henryk Straube
- From the ‡Leibniz Universität Hannover, Institute of Plant Genetics, Herrenhäuser Str. 2, 30419 Hannover, Germany
| | - Linda E Franken
- §Heinrich Pette Institute, Leibniz Institute for Experimental Virology - Centre for Structural Systems Biology, Notkestraβe 85, 22607 Hamburg, Germany
| | - Hans-Peter Braun
- From the ‡Leibniz Universität Hannover, Institute of Plant Genetics, Herrenhäuser Str. 2, 30419 Hannover, Germany
| | - Holger Eubel
- From the ‡Leibniz Universität Hannover, Institute of Plant Genetics, Herrenhäuser Str. 2, 30419 Hannover, Germany;.
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6
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Meyer EH, Welchen E, Carrie C. Assembly of the Complexes of the Oxidative Phosphorylation System in Land Plant Mitochondria. ANNUAL REVIEW OF PLANT BIOLOGY 2019; 70:23-50. [PMID: 30822116 DOI: 10.1146/annurev-arplant-050718-100412] [Citation(s) in RCA: 51] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Plant mitochondria play a major role during respiration by producing the ATP required for metabolism and growth. ATP is produced during oxidative phosphorylation (OXPHOS), a metabolic pathway coupling electron transfer with ADP phosphorylation via the formation and release of a proton gradient across the inner mitochondrial membrane. The OXPHOS system is composed of large, multiprotein complexes coordinating metal-containing cofactors for the transfer of electrons. In this review, we summarize the current state of knowledge about assembly of the OXPHOS complexes in land plants. We present the different steps involved in the formation of functional complexes and the regulatory mechanisms controlling the assembly pathways. Because several assembly steps have been found to be ancestral in plants-compared with those described in fungal and animal models-we discuss the evolutionary dynamics that lead to the conservation of ancestral pathways in land plant mitochondria.
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Affiliation(s)
- Etienne H Meyer
- Organelle Biology and Biotechnology Research Group, Max Planck Institute of Molecular Plant Physiology, 14476 Potsdam-Golm, Germany
- Current affiliation: Institute of Plant Physiology, Martin-Luther-University Halle-Wittenberg, 06120 Halle, Germany;
| | - Elina Welchen
- Cátedra de Biología Celular y Molecular, Instituto de Agrobiotecnología del Litoral (CONICET-UNL), Facultad de Bioquímica y Ciencias Biológicas, Universidad Nacional del Litoral, 3000 Santa Fe, Argentina
| | - Chris Carrie
- Plant Sciences Research Group, Department Biologie I, Ludwig-Maximilians-Universität, 82152 Planegg-Martinsried, Germany
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7
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Simova-Stoilova LP, López-Hidalgo C, Sanchez-Lucas R, Valero-Galvan J, Romero-Rodríguez C, Jorrin-Novo JV. Holm oak proteomic response to water limitation at seedling establishment stage reveals specific changes in different plant parts as well as interaction between roots and cotyledons. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2018; 276:1-13. [PMID: 30348307 DOI: 10.1016/j.plantsci.2018.07.007] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/06/2018] [Revised: 07/17/2018] [Accepted: 07/19/2018] [Indexed: 05/11/2023]
Abstract
Quercus ilex is a dominant tree species in the Mediterranean region with double economic and ecological importance and increasing use in reforestation. Seedling establishment is extremely vulnerable to environmental stresses, particularly drought. A time course study on physiological and proteomic response of holm oak to water limitation stress and recovery during early heterotrophic growth is reported. Applied stress led to diminution in plant water content and root growth, oxidative stress in roots and some alterations in the anti-oxidative protection. Plant parts differed substantially in soluble sugar and free phenolic content, and in their changes during stress and recovery. Proteomic response in holm oak roots and cotyledons was estimated using combined 1-DE/2-DE approach and protein identification by MALDI TOF-TOF PMF and MS/MS. A total of 127 differentially abundant protein species (DAPs) were identified. DAPs related to starch metabolism, lipid to sugar conversion, reserve proteins and their mobilization were typical for cotyledons. DAPs in roots were involved in sugar utilization, secondary metabolism and defense, including pathogenesis related proteins from PR-5 and PR-10 families. Results emphasize specific proteome signatures of separate plant parts as well as importance of sink-source interaction between root and cotyledon in the time course of stress and in recovery.
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Affiliation(s)
- Lyudmila P Simova-Stoilova
- Dept. of Biochemistry and Molecular Biology, University of Cordoba, Agrifood Campus of International Excellence (ceiA3), 14071 Cordoba, Spain; Plant Molecular Biology Dept., Institute of Plant Physiology and Genetics, Bulgarian Academy of Sciences, Acad. G. Bonchev Str. Bl 21, 1113 Sofia, Bulgaria.
| | - Cristina López-Hidalgo
- Dept. of Biochemistry and Molecular Biology, University of Cordoba, Agrifood Campus of International Excellence (ceiA3), 14071 Cordoba, Spain.
| | - Rosa Sanchez-Lucas
- Dept. of Biochemistry and Molecular Biology, University of Cordoba, Agrifood Campus of International Excellence (ceiA3), 14071 Cordoba, Spain.
| | - Jose Valero-Galvan
- Dept. of Biochemistry and Molecular Biology, University of Cordoba, Agrifood Campus of International Excellence (ceiA3), 14071 Cordoba, Spain; Dept. Chemistry-Biology, Biomedical Sciences Institute, Autonomous University of Ciudad Juárez, Anillo Envolvente del Pronaf y Estocolmo s/n, 32310 Ciudad Juarez, Mexico.
| | - Cristina Romero-Rodríguez
- Dept. of Biochemistry and Molecular Biology, University of Cordoba, Agrifood Campus of International Excellence (ceiA3), 14071 Cordoba, Spain; Technological Multidisciplinary Research Centre, National University of Asunción, Paraguay.
| | - Jesus V Jorrin-Novo
- Dept. of Biochemistry and Molecular Biology, University of Cordoba, Agrifood Campus of International Excellence (ceiA3), 14071 Cordoba, Spain.
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8
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Nikonorova N, Yue K, Beeckman T, De Smet I. Arabidopsis research requires a critical re-evaluation of genetic tools. JOURNAL OF EXPERIMENTAL BOTANY 2018; 69:3541-3544. [PMID: 29701839 DOI: 10.1093/jxb/ery161] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/22/2018] [Accepted: 04/10/2018] [Indexed: 06/08/2023]
Abstract
An increasing number of reports question conclusions based on loss-of-function lines that have unexpected genetic backgrounds. In this opinion paper, we urge researchers to meticulously (re)investigate phenotypes retrieved from various genetic backgrounds and be critical regarding some previously drawn conclusions. As an example, we provide new evidence that acr4-2 mutant phenotypes with respect to columella stem cells are due to the lack of ACR4 and not - at least not as a major contributor - to a mutation in QRT1. In addition, we take the opportunity to alert the scientific community about the qrt1-2 background of a large number of Syngenta Arabidopsis Insertion Library (SAIL) T-DNA lines, a feature that is not commonly recognized by Arabidopsis researchers. This qrt1-2 background might have an important impact on the interpretation of the results obtained using these research tools, now and in the past. In conclusion, as a community, we should continuously assess and - if necessary - correct our conclusions based on the large number of (genetic) tools our work is built on. In addition, the positive or negative results of this self-criticism should be made available to the scientific community.
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Affiliation(s)
- Natalia Nikonorova
- Department of Plant Biotechnology and Bioinformatics, Ghent University, Gent, Belgium
- Center for Plant Systems Biology, VIB, Gent, Belgium
| | - Kun Yue
- Department of Plant Biotechnology and Bioinformatics, Ghent University, Gent, Belgium
- Center for Plant Systems Biology, VIB, Gent, Belgium
| | - Tom Beeckman
- Department of Plant Biotechnology and Bioinformatics, Ghent University, Gent, Belgium
- Center for Plant Systems Biology, VIB, Gent, Belgium
| | - Ive De Smet
- Department of Plant Biotechnology and Bioinformatics, Ghent University, Gent, Belgium
- Center for Plant Systems Biology, VIB, Gent, Belgium
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9
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Abstract
A large amount of ultrastructural, biochemical and molecular analysis indicates that peroxisomes and mitochondria not only share the same subcellular space but also maintain considerable overlap in their proteins, responses and functions. Recent approaches using imaging of fluorescent proteins targeted to both organelles in living plant cells are beginning to show the dynamic nature of their interactivity. Based on the observations of living cells, mitochondria respond rapidly to stress by undergoing fission. Mitochondrial fission is suggested to release key membrane-interacting members of the FISSION1 and DYNAMIN RELATED PROTEIN3 families and appears to be followed by the formation of thin peroxisomal extensions called peroxules. In a model we present the peroxules as an intermediate state prior to the formation of tubular peroxisomes, which, in turn are acted upon by the constriction-related proteins released by mitochondria and undergo rapid constriction and fission to increase the number of peroxisomes in a cell. The fluorescent protein aided imaging of peroxisome-mitochondria interaction provides visual evidence for their cooperation in maintenance of cellular homeostasis in plants.
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Affiliation(s)
- Jaideep Mathur
- Laboratory of Plant Development and Interactions, Department of Molecular and Cellular Biology, University of Guelph, 50 Stone Road, Guelph, ON, N1G2W1, Canada.
| | - Aymen Shaikh
- Laboratory of Plant Development and Interactions, Department of Molecular and Cellular Biology, University of Guelph, 50 Stone Road, Guelph, ON, N1G2W1, Canada
| | - Neeta Mathur
- Laboratory of Plant Development and Interactions, Department of Molecular and Cellular Biology, University of Guelph, 50 Stone Road, Guelph, ON, N1G2W1, Canada
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Junková P, Daněk M, Kocourková D, Brouzdová J, Kroumanová K, Zelazny E, Janda M, Hynek R, Martinec J, Valentová O. Mapping of Plasma Membrane Proteins Interacting With Arabidopsis thaliana Flotillin 2. FRONTIERS IN PLANT SCIENCE 2018; 9:991. [PMID: 30050548 PMCID: PMC6052134 DOI: 10.3389/fpls.2018.00991] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2018] [Accepted: 06/19/2018] [Indexed: 05/08/2023]
Abstract
Arabidopsis flotillin 2 (At5g25260) belongs to the group of plant flotillins, which are not well characterized. In contrast, metazoan flotillins are well known as plasma membrane proteins associated with membrane microdomains that act as a signaling hub. The similarity of plant and metazoan flotillins, whose functions most likely consist of affecting other proteins via protein-protein interactions, determines the necessity of detecting their interacting partners in plants. Nevertheless, identifying the proteins that form complexes on the plasma membrane is a challenging task due to their low abundance and hydrophobic character. Here we present an approach for mapping Arabidopsis thaliana flotillin 2 plasma membrane interactors, based on the immunoaffinity purification of crosslinked and enriched plasma membrane proteins with mass spectrometry detection. Using this approach, 61 proteins were enriched in the AtFlot-GFP plasma membrane fraction, and 19 of them were proposed to be flotillin 2 interaction partners. Among our proposed partners of Flot2, proteins playing a role in the plant response to various biotic and abiotic stresses were detected. Additionally, the use of the split-ubiquitin yeast system helped us to confirm that plasma-membrane ATPase 1, early-responsive to dehydration stress protein 4, syntaxin-71, harpin-induced protein-like 3, hypersensitive-induced response protein 2 and two aquaporin isoforms interact with flotillin 2 directly. Based on the results of our study and the reported properties of Flot2 interactors, we propose that Flot2 complexes may be involved in plant-pathogen interactions, water transport and intracellular trafficking.
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Affiliation(s)
- Petra Junková
- Department of Biochemistry and Microbiology, University of Chemistry and Technology Prague, Prague, Czechia
- *Correspondence: Petra Junková, ;
| | - Michal Daněk
- Institute of Experimental Botany of the Czech Academy of Sciences, Prague, Czechia
- Department of Experimental Plant Biology, Faculty of Science, Charles University, Prague, Czechia
| | - Daniela Kocourková
- Institute of Experimental Botany of the Czech Academy of Sciences, Prague, Czechia
| | - Jitka Brouzdová
- Institute of Experimental Botany of the Czech Academy of Sciences, Prague, Czechia
| | - Kristýna Kroumanová
- Institute of Experimental Botany of the Czech Academy of Sciences, Prague, Czechia
| | - Enric Zelazny
- Institut de Biologie Intégrative de la Cellule (I2BC), CNRS–CEA–Université Paris Sud, Université Paris-Saclay, Gif-sur-Yvette, France
| | - Martin Janda
- Department of Biochemistry and Microbiology, University of Chemistry and Technology Prague, Prague, Czechia
- Institute of Experimental Botany of the Czech Academy of Sciences, Prague, Czechia
| | - Radovan Hynek
- Department of Biochemistry and Microbiology, University of Chemistry and Technology Prague, Prague, Czechia
| | - Jan Martinec
- Institute of Experimental Botany of the Czech Academy of Sciences, Prague, Czechia
| | - Olga Valentová
- Department of Biochemistry and Microbiology, University of Chemistry and Technology Prague, Prague, Czechia
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11
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Schwarzländer M, Fuchs P. Plant mitochondrial membranes: adding structure and new functions to respiratory physiology. CURRENT OPINION IN PLANT BIOLOGY 2017; 40:147-157. [PMID: 28992511 DOI: 10.1016/j.pbi.2017.09.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/16/2017] [Revised: 08/31/2017] [Accepted: 09/06/2017] [Indexed: 06/07/2023]
Abstract
The membranes of mitochondria are focal points of cellular physiology and respiratory energy transformation. Recent discoveries have started painting a refined picture of plant mitochondrial membranes as platforms in which structure and function have evolved in an interconnected and dynamically regulated manner. Hosting ancillary functions that interact with other mitochondrial properties gives mitochondria the characteristics of multitasking and integrated molecular mega machines. We review recent insights into the makeup and the plasticity of the outer and inner mitochondrial membranes, their intimate relationship with respiratory function and regulation, and their properties in mediating solute transport. Synthesizing recent research advances we hypothesize that plant mitochondrial membranes are a privileged location for incorporation of a wide range of processes, some of which collaborate with respiratory function, including plant immunity, metabolic regulation and signal transduction, to underpin flexibility in the acclimation to changing environments.
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Affiliation(s)
- Markus Schwarzländer
- Institute of Crop Science and Resource Conservation (INRES), Rheinische Friedrich-Wilhelms-Universität Bonn, Friedrich-Ebert-Allee 144, D-53113 Bonn, Germany; Institute of Plant Biology and Biotechnology, Westfälische Wilhelms-Universität Münster, Schlossplatz 8, D-48143 Münster, Germany.
| | - Philippe Fuchs
- Institute of Crop Science and Resource Conservation (INRES), Rheinische Friedrich-Wilhelms-Universität Bonn, Friedrich-Ebert-Allee 144, D-53113 Bonn, Germany; Institute of Plant Biology and Biotechnology, Westfälische Wilhelms-Universität Münster, Schlossplatz 8, D-48143 Münster, Germany
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12
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Identification of Physiological Substrates and Binding Partners of the Plant Mitochondrial Protease FTSH4 by the Trapping Approach. Int J Mol Sci 2017; 18:ijms18112455. [PMID: 29156584 PMCID: PMC5713422 DOI: 10.3390/ijms18112455] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2017] [Revised: 11/14/2017] [Accepted: 11/16/2017] [Indexed: 11/17/2022] Open
Abstract
Maintenance of functional mitochondria is vital for optimal cell performance and survival. This is accomplished by distinct mechanisms, of which preservation of mitochondrial protein homeostasis fulfills a pivotal role. In plants, inner membrane-embedded i-AAA protease, FTSH4, contributes to the mitochondrial proteome surveillance. Owing to the limited knowledge of FTSH4’s in vivo substrates, very little is known about the pathways and mechanisms directly controlled by this protease. Here, we applied substrate trapping coupled with mass spectrometry-based peptide identification in order to extend the list of FTSH4’s physiological substrates and interaction partners. Our analyses revealed, among several putative targets of FTSH4, novel (mitochondrial pyruvate carrier 4 (MPC4) and Pam18-2) and known (Tim17-2) substrates of this protease. Furthermore, we demonstrate that FTSH4 degrades oxidatively damaged proteins in mitochondria. Our report provides new insights into the function of FTSH4 in the maintenance of plant mitochondrial proteome.
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13
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Liang WW, Huang JH, Li CP, Yang LT, Ye X, Lin D, Chen LS. MicroRNA-mediated responses to long-term magnesium-deficiency in Citrus sinensis roots revealed by Illumina sequencing. BMC Genomics 2017; 18:657. [PMID: 28836935 PMCID: PMC5571589 DOI: 10.1186/s12864-017-3999-5] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2016] [Accepted: 08/01/2017] [Indexed: 01/17/2023] Open
Abstract
Background Magnesium (Mg)-deficiency occurs most frequently in strongly acidic, sandy soils. Citrus are grown mainly on acidic and strong acidic soils. Mg-deficiency causes poor fruit quality and low fruit yield in some Citrus orchards. For the first time, we investigated Mg-deficiency-responsive miRNAs in ‘Xuegan’ (Citrus sinensis) roots using Illumina sequencing in order to obtain some miRNAs presumably responsible for Citrus Mg-deficiency tolerance. Results We obtained 101 (69) miRNAs with increased (decreased) expression from Mg-starved roots. Our results suggested that the adaptation of Citrus roots to Mg-deficiency was related to the several aspects: (a) inhibiting root respiration and related gene expression via inducing miR158 and miR2919; (b) enhancing antioxidant system by down-regulating related miRNAs (miR780, miR6190, miR1044, miR5261 and miR1151) and the adaptation to low-phosphorus (miR6190); (c) activating transport-related genes by altering the expression of miR6190, miR6485, miR1044, miR5029 and miR3437; (d) elevating protein ubiquitination due to decreased expression levels of miR1044, miR5261, miR1151 and miR5029; (e) maintaining root growth by regulating miR5261, miR6485 and miR158 expression; and (f) triggering DNA repair (transcription regulation) by regulating miR5176 and miR6485 (miR6028, miR6190, miR6485, miR5621, miR160 and miR7708) expression. Mg-deficiency-responsive miRNAs involved in root signal transduction also had functions in Citrus Mg-deficiency tolerance. Conclusions We obtained several novel Mg-deficiency-responsive miRNAs (i.e., miR5261, miR158, miR6190, miR6485, miR1151 and miR1044) possibly contributing to Mg-deficiency tolerance. These results revealed some novel clues on the miRNA-mediated adaptation to nutrient deficiencies in higher plants. Electronic supplementary material The online version of this article (doi:10.1186/s12864-017-3999-5) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Wei-Wei Liang
- Institute of Plant Nutritional Physiology and Molecular Biology, College of Resources and Environment, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
| | - Jing-Hao Huang
- Institute of Plant Nutritional Physiology and Molecular Biology, College of Resources and Environment, Fujian Agriculture and Forestry University, Fuzhou, 350002, China.,Pomological Institute, Fujian Academy of Agricultural Sciences, Fuzhou, 350013, China
| | - Chun-Ping Li
- Institute of Plant Nutritional Physiology and Molecular Biology, College of Resources and Environment, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
| | - Lin-Tong Yang
- Institute of Plant Nutritional Physiology and Molecular Biology, College of Resources and Environment, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
| | - Xin Ye
- Institute of Plant Nutritional Physiology and Molecular Biology, College of Resources and Environment, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
| | - Dan Lin
- Institute of Plant Nutritional Physiology and Molecular Biology, College of Resources and Environment, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
| | - Li-Song Chen
- Institute of Plant Nutritional Physiology and Molecular Biology, College of Resources and Environment, Fujian Agriculture and Forestry University, Fuzhou, 350002, China. .,Fujian Provincial Key Laboratory of Soil Environmental Health and Regulation, College of Resources and Environment, Fujian Agriculture and Forestry University, Fuzhou, 350002, China. .,The Higher Educational Key Laboratory of Fujian Province for Soil Ecosystem Health and Regulation, Fujian Agriculture and Forestry University, Fuzhou, 350002, China.
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14
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Opalińska M, Parys K, Murcha MW, Jańska H. Plant i - AAA protease controls the turnover of the essential mitochondrial protein import component. J Cell Sci 2017; 131:jcs.200733. [DOI: 10.1242/jcs.200733] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2016] [Accepted: 03/01/2017] [Indexed: 12/21/2022] Open
Abstract
Mitochondria are multifunctional organelles that play a central role in energy metabolism. Due to life-essential functions of these organelles, mitochondrial content, quality, and dynamics are tightly controlled. Across the species, highly conserved ATP - dependent proteases prevent malfunction of mitochondria through versatile activities. This study focuses on a molecular function of plant mitochondrial inner membrane-embedded i – AAA protease, FTSH4, providing its first bona fide substrate. Here, we report that the abundance of Tim17-2 protein, the essential component of the TIM17:23 translocase, is directly controlled by the proteolytic activity of FTSH4. Plants that are lacking functional FTSH4 protease are characterized by significantly enhanced capacity of preprotein import through the TIM17:23 - dependent pathway. Together with the observation that FTSH4 prevents accumulation of Tim17-2, our data points towards the role of this i - AAA protease in the regulation of mitochondrial biogenesis in plants.
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Affiliation(s)
- Magdalena Opalińska
- Faculty of Biotechnology, University of Wroclaw, F. Joliot-Curie 14A, 50-383 Wroclaw, Poland
| | - Katarzyna Parys
- Faculty of Biotechnology, University of Wroclaw, F. Joliot-Curie 14A, 50-383 Wroclaw, Poland
- Present address: Gregor Mendel Institute, Austrian Academy of Sciences, Vienna Biocenter, A-1030 Vienna, Austria
| | - Monika W. Murcha
- Australian Research Council Centre of Excellence in Plant Energy Biology, University of Western Australia, 35 Stirling Highway, Crawley, 6009, Western Australia
- School of Molecular Sciences, University of Western Australia, 35 Stirling Highway, Crawley, 6009, Western Australia
| | - Hanna Jańska
- Faculty of Biotechnology, University of Wroclaw, F. Joliot-Curie 14A, 50-383 Wroclaw, Poland
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15
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Lee CP, Maksaev G, Jensen GS, Murcha MW, Wilson ME, Fricker M, Hell R, Haswell ES, Millar AH, Sweetlove LJ. MSL1 is a mechanosensitive ion channel that dissipates mitochondrial membrane potential and maintains redox homeostasis in mitochondria during abiotic stress. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2016; 88:809-825. [PMID: 27505616 PMCID: PMC5195915 DOI: 10.1111/tpj.13301] [Citation(s) in RCA: 58] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/24/2016] [Revised: 08/04/2016] [Accepted: 08/05/2016] [Indexed: 05/18/2023]
Abstract
Mitochondria must maintain tight control over the electrochemical gradient across their inner membrane to allow ATP synthesis while maintaining a redox-balanced electron transport chain and avoiding excessive reactive oxygen species production. However, there is a scarcity of knowledge about the ion transporters in the inner mitochondrial membrane that contribute to control of membrane potential. We show that loss of MSL1, a member of a family of mechanosensitive ion channels related to the bacterial channel MscS, leads to increased membrane potential of Arabidopsis mitochondria under specific bioenergetic states. We demonstrate that MSL1 localises to the inner mitochondrial membrane. When expressed in Escherichia coli, MSL1 forms a stretch-activated ion channel with a slight preference for anions and provides protection against hypo-osmotic shock. In contrast, loss of MSL1 in Arabidopsis did not prevent swelling of isolated mitochondria in hypo-osmotic conditions. Instead, our data suggest that ion transport by MSL1 leads to dissipation of mitochondrial membrane potential when it becomes too high. The importance of MSL1 function was demonstrated by the observation of a higher oxidation state of the mitochondrial glutathione pool in msl1-1 mutants under moderate heat- and heavy-metal-stress. Furthermore, we show that MSL1 function is not directly implicated in mitochondrial membrane potential pulsing, but is complementary and appears to be important under similar conditions.
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Affiliation(s)
- Chun Pong Lee
- ARC Centre of Excellence in Plant Energy Biology, University of Western Australia, Bayliss Building M316, 35 Stirling Highway, Crawley, 6009, Western Australia, Australia
| | - Grigory Maksaev
- Department of Biology, Washington University in Saint Louis, One Brookings Drive, Mailcode 1137, Saint Louis, MO, 63130, USA
| | - Gregory S Jensen
- Department of Biology, Washington University in Saint Louis, One Brookings Drive, Mailcode 1137, Saint Louis, MO, 63130, USA
| | - Monika W Murcha
- ARC Centre of Excellence in Plant Energy Biology, University of Western Australia, Bayliss Building M316, 35 Stirling Highway, Crawley, 6009, Western Australia, Australia
| | - Margaret E Wilson
- Department of Biology, Washington University in Saint Louis, One Brookings Drive, Mailcode 1137, Saint Louis, MO, 63130, USA
| | - Mark Fricker
- Department of Plant Sciences, University of Oxford, South Parks Road, Oxford, OX1 3RB, UK
| | - Ruediger Hell
- Department of Plant Molecular Biology, Centre for Organismal Studies, University of Heidelberg, Im Neuenheimer Feld 360, D-69120, Heidelberg, Germany
| | - Elizabeth S Haswell
- Department of Biology, Washington University in Saint Louis, One Brookings Drive, Mailcode 1137, Saint Louis, MO, 63130, USA
| | - A Harvey Millar
- ARC Centre of Excellence in Plant Energy Biology, University of Western Australia, Bayliss Building M316, 35 Stirling Highway, Crawley, 6009, Western Australia, Australia
| | - Lee J Sweetlove
- Department of Plant Sciences, University of Oxford, South Parks Road, Oxford, OX1 3RB, UK
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16
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Van Aken O, Ford E, Lister R, Huang S, Millar AH. Retrograde signalling caused by heritable mitochondrial dysfunction is partially mediated by ANAC017 and improves plant performance. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2016; 88:542-558. [PMID: 27425258 DOI: 10.1111/tpj.13276] [Citation(s) in RCA: 49] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/05/2016] [Revised: 07/12/2016] [Accepted: 07/14/2016] [Indexed: 06/06/2023]
Abstract
Mitochondria are crucial for plant viability and are able to communicate information on their functional status to the cellular nucleus via retrograde signalling, thereby affecting gene expression. It is currently unclear if retrograde signalling in response to constitutive mitochondrial biogenesis defects is mediated by the same pathways as those triggered during acute mitochondrial dysfunction. Furthermore, it is unknown if retrograde signalling can effectively improve plant performance when mitochondrial function is constitutively impaired. Here we show that retrograde signalling in mutants defective in mitochondrial proteins RNA polymerase rpotmp or prohibitin atphb3 can be suppressed by knocking out the transcription factor ANAC017. Genome-wide RNA-seq expression analysis revealed that ANAC017 is almost solely responsible for the most dramatic transcriptional changes common to rpotmp and atphb3 mutants, regulating classical marker genes such as alternative oxidase 1a (AOX1a) and also previously-uncharacterised DUF295 genes that appear to be new retrograde markers. In contrast, ANAC017 does not regulate intra-mitochondrial gene expression or transcriptional changes unique to either rpotmp or atphb3 genotype, suggesting the existence of currently unknown signalling cascades. The data show that ANAC017 function extends beyond common retrograde transcriptional responses and affects downstream protein abundance and enzyme activity of alternative oxidase, as well as steady-state energy metabolism in atphb3 plants. Furthermore, detailed growth analysis revealed that ANAC017-dependent retrograde signalling provides benefits for growth and productivity in plants with mitochondrial defects. In conclusion, ANAC017 plays a key role in both biogenic and operational mitochondrial retrograde signalling, and improves plant performance when mitochondrial function is constitutively impaired.
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Affiliation(s)
- Olivier Van Aken
- Faculty of Science, ARC Centre of Excellence in Plant Energy Biology, The University of Western Australia, Bayliss Building M316, 35 Stirling Highway, Crawley, 6009, Western Australia, Australia
| | - Ethan Ford
- Faculty of Science, ARC Centre of Excellence in Plant Energy Biology, The University of Western Australia, Bayliss Building M316, 35 Stirling Highway, Crawley, 6009, Western Australia, Australia
| | - Ryan Lister
- Faculty of Science, ARC Centre of Excellence in Plant Energy Biology, The University of Western Australia, Bayliss Building M316, 35 Stirling Highway, Crawley, 6009, Western Australia, Australia
| | - Shaobai Huang
- Faculty of Science, ARC Centre of Excellence in Plant Energy Biology, The University of Western Australia, Bayliss Building M316, 35 Stirling Highway, Crawley, 6009, Western Australia, Australia
| | - A Harvey Millar
- Faculty of Science, ARC Centre of Excellence in Plant Energy Biology, The University of Western Australia, Bayliss Building M316, 35 Stirling Highway, Crawley, 6009, Western Australia, Australia
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17
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Wang Y, Lyu W, Berkowitz O, Radomiljac JD, Law SR, Murcha MW, Carrie C, Teixeira PF, Kmiec B, Duncan O, Van Aken O, Narsai R, Glaser E, Huang S, Roessner U, Millar AH, Whelan J. Inactivation of Mitochondrial Complex I Induces the Expression of a Twin Cysteine Protein that Targets and Affects Cytosolic, Chloroplastidic and Mitochondrial Function. MOLECULAR PLANT 2016; 9:696-710. [PMID: 26829715 DOI: 10.1016/j.molp.2016.01.009] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/11/2015] [Revised: 12/09/2015] [Accepted: 01/06/2016] [Indexed: 06/05/2023]
Abstract
At12Cys-1 (At5g64400) and At12Cys-2 (At5g09570) are two closely related isogenes that encode small, twin cysteine proteins, typically located in mitochondria. At12Cys-2 transcript is induced in a variety of mutants with disrupted mitochondrial proteins, but an increase in At12Cys protein is only detected in mutants with reduced mitochondrial complex I abundance. Induction of At12Cys protein in mutants that lack mitochondrial complex I is accompanied by At12Cys protein located in mitochondria, chloroplasts, and the cytosol. Biochemical analyses revealed that even single gene deletions, i.e., At12cys-1 or At12cys-2, have an effect on mitochondrial and chloroplast functions. However, only double mutants, i.e., At12cys-1:At12cys-2, affect the abundance of protein and mRNA transcripts encoding translation elongation factors as well as rRNA abundance. Blue native PAGE showed that At12Cys co-migrated with mitochondrial supercomplex I + III. Likewise, deletion of both At12cys-1 and At12cys-2 genes, but not single gene deletions, results in enhanced tolerance to drought and light stress and increased anti-oxidant capacity. The induction and multiple localization of At12Cys upon a reduction in complex I abundance provides a mechanism to specifically signal mitochondrial dysfunction to the cytosol and then beyond to other organelles in the cell.
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Affiliation(s)
- Yan Wang
- Department of Animal, Plant and Soil Science, Australian Research Council Centre of Excellence in Plant Energy Biology, School of Life Science, La Trobe University, Bundoora, VIC 3086, Australia
| | - Wenhui Lyu
- Department of Animal, Plant and Soil Science, Australian Research Council Centre of Excellence in Plant Energy Biology, School of Life Science, La Trobe University, Bundoora, VIC 3086, Australia
| | - Oliver Berkowitz
- Department of Animal, Plant and Soil Science, Australian Research Council Centre of Excellence in Plant Energy Biology, School of Life Science, La Trobe University, Bundoora, VIC 3086, Australia
| | - Jordan D Radomiljac
- Department of Animal, Plant and Soil Science, Australian Research Council Centre of Excellence in Plant Energy Biology, School of Life Science, La Trobe University, Bundoora, VIC 3086, Australia
| | - Simon R Law
- Umeå Plant Science Centre (UPSC), Faculty of Science and Technology, Umeå University, Umeå, Sweden
| | - Monika W Murcha
- Australian Research Council Centre of Excellence in Plant Energy Biology, University of Western Australia, 35 Stirling Highway, Crawley, WA 6009, Australia
| | - Chris Carrie
- Department of Biology I, Botany, Ludwig-Maximilians-Universität München, Großhaderner Strasse 2-4, 82152 Planegg-Martinsried, Germany
| | - Pedro F Teixeira
- Department of Biochemistry and Biophysics, Stockholm University, Arrhenius Laboratories for Natural Sciences, 10691 Stockholm, Sweden
| | - Beata Kmiec
- Department of Biochemistry and Biophysics, Stockholm University, Arrhenius Laboratories for Natural Sciences, 10691 Stockholm, Sweden
| | - Owen Duncan
- Australian Research Council Centre of Excellence in Plant Energy Biology, University of Western Australia, 35 Stirling Highway, Crawley, WA 6009, Australia
| | - Olivier Van Aken
- Australian Research Council Centre of Excellence in Plant Energy Biology, University of Western Australia, 35 Stirling Highway, Crawley, WA 6009, Australia
| | - Reena Narsai
- Department of Animal, Plant and Soil Science, Australian Research Council Centre of Excellence in Plant Energy Biology, School of Life Science, La Trobe University, Bundoora, VIC 3086, Australia
| | - Elzbieta Glaser
- Department of Biochemistry and Biophysics, Stockholm University, Arrhenius Laboratories for Natural Sciences, 10691 Stockholm, Sweden
| | - Shaobai Huang
- Australian Research Council Centre of Excellence in Plant Energy Biology, University of Western Australia, 35 Stirling Highway, Crawley, WA 6009, Australia
| | - Ute Roessner
- School of BioSciences, The University of Melbourne, Melbourne, VIC 3010, Australia
| | - A Harvey Millar
- Australian Research Council Centre of Excellence in Plant Energy Biology, University of Western Australia, 35 Stirling Highway, Crawley, WA 6009, Australia
| | - James Whelan
- Department of Animal, Plant and Soil Science, Australian Research Council Centre of Excellence in Plant Energy Biology, School of Life Science, La Trobe University, Bundoora, VIC 3086, Australia.
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18
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Fromm S, Senkler J, Eubel H, Peterhänsel C, Braun HP. Life without complex I: proteome analyses of an Arabidopsis mutant lacking the mitochondrial NADH dehydrogenase complex. JOURNAL OF EXPERIMENTAL BOTANY 2016; 67:3079-93. [PMID: 27122571 PMCID: PMC4867900 DOI: 10.1093/jxb/erw165] [Citation(s) in RCA: 65] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
The mitochondrial NADH dehydrogenase complex (complex I) is of particular importance for the respiratory chain in mitochondria. It is the major electron entry site for the mitochondrial electron transport chain (mETC) and therefore of great significance for mitochondrial ATP generation. We recently described an Arabidopsis thaliana double-mutant lacking the genes encoding the carbonic anhydrases CA1 and CA2, which both form part of a plant-specific 'carbonic anhydrase domain' of mitochondrial complex I. The mutant lacks complex I completely. Here we report extended analyses for systematically characterizing the proteome of the ca1ca2 mutant. Using various proteomic tools, we show that lack of complex I causes reorganization of the cellular respiration system. Reduced electron entry into the respiratory chain at the first segment of the mETC leads to induction of complexes II and IV as well as alternative oxidase. Increased electron entry at later segments of the mETC requires an increase in oxidation of organic substrates. This is reflected by higher abundance of proteins involved in glycolysis, the tricarboxylic acid cycle and branched-chain amino acid catabolism. Proteins involved in the light reaction of photosynthesis, the Calvin cycle, tetrapyrrole biosynthesis, and photorespiration are clearly reduced, contributing to the significant delay in growth and development of the double-mutant. Finally, enzymes involved in defense against reactive oxygen species and stress symptoms are much induced. These together with previously reported insights into the function of plant complex I, which were obtained by analysing other complex I mutants, are integrated in order to comprehensively describe 'life without complex I'.
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Affiliation(s)
- Steffanie Fromm
- Institut für Pflanzengenetik, Leibniz Universität Hannover, Herrenhäuser Str. 2, 30419 Hannover, Germany Institut für Botanik, Leibniz Universität Hannover, Herrenhäuser Str. 2, 30419 Hannover, Germany
| | - Jennifer Senkler
- Institut für Pflanzengenetik, Leibniz Universität Hannover, Herrenhäuser Str. 2, 30419 Hannover, Germany
| | - Holger Eubel
- Institut für Pflanzengenetik, Leibniz Universität Hannover, Herrenhäuser Str. 2, 30419 Hannover, Germany
| | - Christoph Peterhänsel
- Institut für Botanik, Leibniz Universität Hannover, Herrenhäuser Str. 2, 30419 Hannover, Germany
| | - Hans-Peter Braun
- Institut für Pflanzengenetik, Leibniz Universität Hannover, Herrenhäuser Str. 2, 30419 Hannover, Germany
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19
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Cogliati S, Enriquez JA, Scorrano L. Mitochondrial Cristae: Where Beauty Meets Functionality. Trends Biochem Sci 2016; 41:261-273. [PMID: 26857402 DOI: 10.1016/j.tibs.2016.01.001] [Citation(s) in RCA: 523] [Impact Index Per Article: 65.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2015] [Revised: 01/07/2016] [Accepted: 01/08/2016] [Indexed: 01/30/2023]
Abstract
Mitochondrial cristae are dynamic bioenergetic compartments whose shape changes under different physiological conditions. Recent discoveries have unveiled the relation between cristae shape and oxidative phosphorylation (OXPHOS) function, suggesting that membrane morphology modulates the organization and function of the OXPHOS system, with a direct impact on cellular metabolism. As a corollary, cristae-shaping proteins have emerged as potential modulators of mitochondrial bioenergetics, a concept confirmed by genetic experiments in mouse models of respiratory chain deficiency. Here, we review our knowledge of mitochondrial ultrastructural organization and how it impacts mitochondrial metabolism.
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Affiliation(s)
- Sara Cogliati
- Centro Nacional de Investigaciònes Cardiovasculares Carlos III, Madrid, Spain
| | - Jose A Enriquez
- Centro Nacional de Investigaciònes Cardiovasculares Carlos III, Madrid, Spain; Departamento de Bioquímica, Universidad Zaragoza, Zaragoza, Spain
| | - Luca Scorrano
- Dulbecco Telethon Institute, Venetian Institute of Molecular Medicine, Padova, Italy; Department of Biology, University of Padova, Padova, Italy.
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20
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Chi H, Hu YH. Stomatin-like protein 2 of turbot Scopthalmus maximus: Gene cloning, expression profiling and immunoregulatory properties. FISH & SHELLFISH IMMUNOLOGY 2016; 49:436-441. [PMID: 26806162 DOI: 10.1016/j.fsi.2016.01.014] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/27/2015] [Revised: 01/08/2016] [Accepted: 01/11/2016] [Indexed: 06/05/2023]
Abstract
Stomatin-like protein 2 (SLP-2) is a novel and unusual member of the stomatin gene superfamily. In this study, we obtained a full-length SLP-2 (SmSLP-2) cDNA from turbot (Scopthalmus maximus) spleen cDNA library. The cDNA sequence of SmSLP-2 contains a 5'-UTR of 107 bp, an ORF of 1050 bp, and a 3'-UTR of 959 bp. The ORF encodes a putative protein of 349 residues, which has a calculated molecular mass of 38.7 kDa. The SmSLP-2 protein possesses a prohibitin-homology (PHB) domain (residues 40 to 198) and shares 72.4-87.6% overall sequence identity with that of the teleost species. The highest expression of SmSLP-2 mRNA was found in the skin, followed by the head kidney, gut, spleen, liver, heart, gill and muscle. Moreover, both viral and bacterial pathogen infection resulted in the up-regulation of SmSLP-2 mRNA in the turbot head kidney and spleen in vivo. Subcellular localization analysis indicated that the SmSLP-2 proteins are mainly located in the peripheral membrane of ZF4 cells. This study also demonstrated that SmSLP-2 modulates IL-2 expression via active NFκB signaling pathway, and is possibly involved in host immune defense against bacterial and viral pathogens.
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Affiliation(s)
- Heng Chi
- Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China; Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266237, China
| | - Yong-Hua Hu
- Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China; Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266237, China.
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21
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Abstract
Since the discovery of the existence of superassemblies between mitochondrial respiratory complexes, such superassemblies have been the object of a passionate debate. It is accepted that respiratory supercomplexes are structures that occur in vivo, although which superstructures are naturally occurring and what could be their functional role remain open questions. The main difficulty is to make compatible the existence of superassemblies with the corpus of data that drove the field to abandon the early understanding of the physical arrangement of the mitochondrial respiratory chain as a compact physical entity (the solid model). This review provides a nonexhaustive overview of the evolution of our understanding of the structural organization of the electron transport chain from the original idea of a compact organization to a view of freely moving complexes connected by electron carriers. Today supercomplexes are viewed not as a revival of the old solid model but rather as a refined revision of the fluid model, which incorporates a new layer of structural and functional complexity.
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Affiliation(s)
- José Antonio Enríquez
- Centro Nacional de Investigaciones Cardiovasculares Carlos III (CNIC), 28029 Madrid, Spain;
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22
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Magalon A, Alberge F. Distribution and dynamics of OXPHOS complexes in the bacterial cytoplasmic membrane. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2015; 1857:198-213. [PMID: 26545610 DOI: 10.1016/j.bbabio.2015.10.015] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/24/2015] [Revised: 10/28/2015] [Accepted: 10/29/2015] [Indexed: 12/23/2022]
Abstract
Oxidative phosphorylation (OXPHOS) is an essential process for most living organisms mostly sustained by protein complexes embedded in the cell membrane. In order to thrive, cells need to quickly respond to changes in the metabolic demand or in their environment. An overview of the strategies that can be employed by bacterial cells to adjust the OXPHOS outcome is provided. Regulation at the level of gene expression can only provide a means to adjust the OXPHOS outcome to long-term trends in the environment. In addition, the actual view is that bioenergetic membranes are highly compartmentalized structures. This review discusses what is known about the spatial organization of OXPHOS complexes and the timescales at which they occur. As exemplified with the commensal gut bacterium Escherichia coli, three levels of spatial organization are at play: supercomplexes, membrane microdomains and polar assemblies. This review provides a particular focus on whether dynamic spatial organization can fine-tune the OXPHOS through the definition of specialized functional membrane microdomains. Putative mechanisms responsible for spatio-temporal regulation of the OXPHOS complexes are discussed. This article is part of a Special Issue entitled Organization and dynamics of bioenergetic systems in bacteria, edited by Conrad Mullineaux.
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Affiliation(s)
- Axel Magalon
- CNRS, Laboratoire de Chimie Bactérienne (UMR 7283), Institut de Microbiologie de la Méditerranée, 13009 Marseille, France; Aix-Marseille University, UMR 7283, 13009 Marseille, France.
| | - François Alberge
- CNRS, Laboratoire de Chimie Bactérienne (UMR 7283), Institut de Microbiologie de la Méditerranée, 13009 Marseille, France; Aix-Marseille University, UMR 7283, 13009 Marseille, France
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23
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Piechota J, Bereza M, Sokołowska A, Suszyński K, Lech K, Jańska H. Unraveling the functions of type II-prohibitins in Arabidopsis mitochondria. PLANT MOLECULAR BIOLOGY 2015; 88:249-267. [PMID: 25896400 DOI: 10.1007/s11103-015-0320-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/03/2014] [Accepted: 04/07/2015] [Indexed: 06/04/2023]
Abstract
In yeast and mammals, prohibitins (PHBs) are considered as structural proteins that form a scaffold-like structure for interacting with a set of proteins involved in various processes occurring in the mitochondria. The role of PHB in plant mitochondria is poorly understood. In the study, the model organism Arabidopsis thaliana was used to identify the possible roles of type-II PHBs (homologs of yeast Phb2p) in plant mitochondria. The obtained results suggest that the plant PHB complex participates in the assembly of multisubunit complexes; namely, respiratory complex I and enzymatic complexes carrying lipoic acid as a cofactor (pyruvate dehydrogenase, 2-oxoglutarate dehydrogenase and glycine decarboxylase). PHBs physically interact with subunits of these complexes. Knockout of two Arabidopsis type-II prohibitins (AtPHB2 and AtPHB6) results in a decreased abundance of these complexes along with a reduction in mitochondrial acyl carrier proteins. Also, the absence of AtPHB2 and AtPHB6 influences the expression of the mitochondrial genome and leads to the activation of alternative respiratory pathways, namely alternative oxidase and external NADH-dependent alternative dehydrogenases.
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Affiliation(s)
- Janusz Piechota
- Department of Biotechnology, University of Wroclaw, F. Juliot-Curie 14a, 50-383, Wroclaw, Poland,
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24
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Stomatin-like protein 2 is required for in vivo mitochondrial respiratory chain supercomplex formation and optimal cell function. Mol Cell Biol 2015; 35:1838-47. [PMID: 25776552 DOI: 10.1128/mcb.00047-15] [Citation(s) in RCA: 64] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2015] [Accepted: 03/05/2015] [Indexed: 11/20/2022] Open
Abstract
Stomatin-like protein 2 (SLP-2) is a mainly mitochondrial protein that is widely expressed and is highly conserved across evolution. We have previously shown that SLP-2 binds the mitochondrial lipid cardiolipin and interacts with prohibitin-1 and -2 to form specialized membrane microdomains in the mitochondrial inner membrane, which are associated with optimal mitochondrial respiration. To determine how SLP-2 functions, we performed bioenergetic analysis of primary T cells from T cell-selective Slp-2 knockout mice under conditions that forced energy production to come almost exclusively from oxidative phosphorylation. These cells had a phenotype characterized by increased uncoupled mitochondrial respiration and decreased mitochondrial membrane potential. Since formation of mitochondrial respiratory chain supercomplexes (RCS) may correlate with more efficient electron transfer during oxidative phosphorylation, we hypothesized that the defect in mitochondrial respiration in SLP-2-deficient T cells was due to deficient RCS formation. We found that in the absence of SLP-2, T cells had decreased levels and activities of complex I-III2 and I-III2-IV(1-3) RCS but no defects in assembly of individual respiratory complexes. Impaired RCS formation in SLP-2-deficient T cells correlated with significantly delayed T cell proliferation in response to activation under conditions of limiting glycolysis. Altogether, our findings identify SLP-2 as a key regulator of the formation of RCS in vivo and show that these supercomplexes are required for optimal cell function.
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Jacoby RP, Millar AH, Taylor NL. Assessment of respiration in isolated plant mitochondria using Clark-type electrodes. Methods Mol Biol 2015; 1305:165-185. [PMID: 25910734 DOI: 10.1007/978-1-4939-2639-8_12] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Mitochondrial respiration involves two key gas exchanges, the consumption of oxygen and the release of carbon dioxide. The ability to measure the consumption of oxygen via Clark-type electrodes has been one of the key techniques for advancing our knowledge of mitochondrial function in whole organisms, tissue samples, cells, and isolated subcellular fractions. In plants, oxygen electrode analyses provided the first evidence for some of the unique respiratory properties of plant mitochondria. This chapter briefs the principles of respiration and oxidative phosphorylation, how oxygen consumption measurements can be used to assess the quality of isolated mitochondrial preparations, and how these measurements can answer important questions in plant biochemistry and physiology. Finally, it presents instructions on assembling the oxygen electrode apparatus and how to conduct various assays.
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Affiliation(s)
- Richard P Jacoby
- Plant Energy Biology, Australian Research Council Centre of Excellence in Plant Energy Biology, The University of Western Australia, 35 Stirling Highway, Crawley, WA, 6009, Australia
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Ivanova A, Law SR, Narsai R, Duncan O, Lee JH, Zhang B, Van Aken O, Radomiljac JD, van der Merwe M, Yi K, Whelan J. A Functional Antagonistic Relationship between Auxin and Mitochondrial Retrograde Signaling Regulates Alternative Oxidase1a Expression in Arabidopsis. PLANT PHYSIOLOGY 2014; 165:1233-1254. [PMID: 24820025 PMCID: PMC4081334 DOI: 10.1104/pp.114.237495] [Citation(s) in RCA: 76] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/07/2014] [Accepted: 05/04/2014] [Indexed: 05/18/2023]
Abstract
The perception and integration of stress stimuli with that of mitochondrion function are important during periods of perturbed cellular homeostasis. In a continuous effort to delineate these mitochondrial/stress-interacting networks, forward genetic screens using the mitochondrial stress response marker alternative oxidase 1a (AOX1a) provide a useful molecular tool to identify and characterize regulators of mitochondrial stress signaling (referred to as regulators of alternative oxidase 1a [RAOs] components). In this study, we reveal that mutations in genes coding for proteins associated with auxin transport and distribution resulted in a greater induction of AOX1a in terms of magnitude and longevity. Three independent mutants for polarized auxin transport, rao3/big, rao4/pin-formed1, and rao5/multidrug-resistance1/abcb19, as well as the Myb transcription factor rao6/asymmetric leaves1 (that displays altered auxin patterns) were identified and resulted in an acute sensitivity toward mitochondrial dysfunction. Induction of the AOX1a reporter system could be inhibited by the application of auxin analogs or reciprocally potentiated by blocking auxin transport. Promoter activation studies with AOX1a::GUS and DR5::GUS lines further confirmed a clear antagonistic relationship between the spatial distribution of mitochondrial stress and auxin response kinetics, respectively. Genome-wide transcriptome analyses revealed that mitochondrial stress stimuli, such as antimycin A, caused a transient suppression of auxin signaling and conversely, that auxin treatment repressed a part of the response to antimycin A treatment, including AOX1a induction. We conclude that mitochondrial stress signaling and auxin signaling are reciprocally regulated, balancing growth and stress response(s).
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Affiliation(s)
- Aneta Ivanova
- Australian Research Council Centre of Excellence in Plant Energy Biology, Department of Botany, School of Life Science, La Trobe University, Bundoora, Victoria 3086, Australia (A.I., S.R.L., O.D., B.Z., J.D.R., J.W.);Australian Research Council Centre of Excellence in Plant Energy Biology, University of Western Australia, Crawley, Western Australia 6009, Australia (A.I., R.N., J.-H.L., O.V.A., J.D.R., M.v.d.M.); andState Key Laboratory Breeding Base for Zhejiang Sustainable Pest and Disease Control, Zhejiang Academy of Agricultural Sciences, Hangzhou 310021, China (K.Y.)
| | - Simon R Law
- Australian Research Council Centre of Excellence in Plant Energy Biology, Department of Botany, School of Life Science, La Trobe University, Bundoora, Victoria 3086, Australia (A.I., S.R.L., O.D., B.Z., J.D.R., J.W.);Australian Research Council Centre of Excellence in Plant Energy Biology, University of Western Australia, Crawley, Western Australia 6009, Australia (A.I., R.N., J.-H.L., O.V.A., J.D.R., M.v.d.M.); andState Key Laboratory Breeding Base for Zhejiang Sustainable Pest and Disease Control, Zhejiang Academy of Agricultural Sciences, Hangzhou 310021, China (K.Y.)
| | - Reena Narsai
- Australian Research Council Centre of Excellence in Plant Energy Biology, Department of Botany, School of Life Science, La Trobe University, Bundoora, Victoria 3086, Australia (A.I., S.R.L., O.D., B.Z., J.D.R., J.W.);Australian Research Council Centre of Excellence in Plant Energy Biology, University of Western Australia, Crawley, Western Australia 6009, Australia (A.I., R.N., J.-H.L., O.V.A., J.D.R., M.v.d.M.); andState Key Laboratory Breeding Base for Zhejiang Sustainable Pest and Disease Control, Zhejiang Academy of Agricultural Sciences, Hangzhou 310021, China (K.Y.)
| | - Owen Duncan
- Australian Research Council Centre of Excellence in Plant Energy Biology, Department of Botany, School of Life Science, La Trobe University, Bundoora, Victoria 3086, Australia (A.I., S.R.L., O.D., B.Z., J.D.R., J.W.);Australian Research Council Centre of Excellence in Plant Energy Biology, University of Western Australia, Crawley, Western Australia 6009, Australia (A.I., R.N., J.-H.L., O.V.A., J.D.R., M.v.d.M.); andState Key Laboratory Breeding Base for Zhejiang Sustainable Pest and Disease Control, Zhejiang Academy of Agricultural Sciences, Hangzhou 310021, China (K.Y.)
| | - Jae-Hoon Lee
- Australian Research Council Centre of Excellence in Plant Energy Biology, Department of Botany, School of Life Science, La Trobe University, Bundoora, Victoria 3086, Australia (A.I., S.R.L., O.D., B.Z., J.D.R., J.W.);Australian Research Council Centre of Excellence in Plant Energy Biology, University of Western Australia, Crawley, Western Australia 6009, Australia (A.I., R.N., J.-H.L., O.V.A., J.D.R., M.v.d.M.); andState Key Laboratory Breeding Base for Zhejiang Sustainable Pest and Disease Control, Zhejiang Academy of Agricultural Sciences, Hangzhou 310021, China (K.Y.)
| | - Botao Zhang
- Australian Research Council Centre of Excellence in Plant Energy Biology, Department of Botany, School of Life Science, La Trobe University, Bundoora, Victoria 3086, Australia (A.I., S.R.L., O.D., B.Z., J.D.R., J.W.);Australian Research Council Centre of Excellence in Plant Energy Biology, University of Western Australia, Crawley, Western Australia 6009, Australia (A.I., R.N., J.-H.L., O.V.A., J.D.R., M.v.d.M.); andState Key Laboratory Breeding Base for Zhejiang Sustainable Pest and Disease Control, Zhejiang Academy of Agricultural Sciences, Hangzhou 310021, China (K.Y.)
| | - Olivier Van Aken
- Australian Research Council Centre of Excellence in Plant Energy Biology, Department of Botany, School of Life Science, La Trobe University, Bundoora, Victoria 3086, Australia (A.I., S.R.L., O.D., B.Z., J.D.R., J.W.);Australian Research Council Centre of Excellence in Plant Energy Biology, University of Western Australia, Crawley, Western Australia 6009, Australia (A.I., R.N., J.-H.L., O.V.A., J.D.R., M.v.d.M.); andState Key Laboratory Breeding Base for Zhejiang Sustainable Pest and Disease Control, Zhejiang Academy of Agricultural Sciences, Hangzhou 310021, China (K.Y.)
| | - Jordan D Radomiljac
- Australian Research Council Centre of Excellence in Plant Energy Biology, Department of Botany, School of Life Science, La Trobe University, Bundoora, Victoria 3086, Australia (A.I., S.R.L., O.D., B.Z., J.D.R., J.W.);Australian Research Council Centre of Excellence in Plant Energy Biology, University of Western Australia, Crawley, Western Australia 6009, Australia (A.I., R.N., J.-H.L., O.V.A., J.D.R., M.v.d.M.); andState Key Laboratory Breeding Base for Zhejiang Sustainable Pest and Disease Control, Zhejiang Academy of Agricultural Sciences, Hangzhou 310021, China (K.Y.)
| | - Margaretha van der Merwe
- Australian Research Council Centre of Excellence in Plant Energy Biology, Department of Botany, School of Life Science, La Trobe University, Bundoora, Victoria 3086, Australia (A.I., S.R.L., O.D., B.Z., J.D.R., J.W.);Australian Research Council Centre of Excellence in Plant Energy Biology, University of Western Australia, Crawley, Western Australia 6009, Australia (A.I., R.N., J.-H.L., O.V.A., J.D.R., M.v.d.M.); andState Key Laboratory Breeding Base for Zhejiang Sustainable Pest and Disease Control, Zhejiang Academy of Agricultural Sciences, Hangzhou 310021, China (K.Y.)
| | - KeKe Yi
- Australian Research Council Centre of Excellence in Plant Energy Biology, Department of Botany, School of Life Science, La Trobe University, Bundoora, Victoria 3086, Australia (A.I., S.R.L., O.D., B.Z., J.D.R., J.W.);Australian Research Council Centre of Excellence in Plant Energy Biology, University of Western Australia, Crawley, Western Australia 6009, Australia (A.I., R.N., J.-H.L., O.V.A., J.D.R., M.v.d.M.); andState Key Laboratory Breeding Base for Zhejiang Sustainable Pest and Disease Control, Zhejiang Academy of Agricultural Sciences, Hangzhou 310021, China (K.Y.)
| | - James Whelan
- Australian Research Council Centre of Excellence in Plant Energy Biology, Department of Botany, School of Life Science, La Trobe University, Bundoora, Victoria 3086, Australia (A.I., S.R.L., O.D., B.Z., J.D.R., J.W.);Australian Research Council Centre of Excellence in Plant Energy Biology, University of Western Australia, Crawley, Western Australia 6009, Australia (A.I., R.N., J.-H.L., O.V.A., J.D.R., M.v.d.M.); andState Key Laboratory Breeding Base for Zhejiang Sustainable Pest and Disease Control, Zhejiang Academy of Agricultural Sciences, Hangzhou 310021, China (K.Y.)
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Gehl B, Sweetlove LJ. Mitochondrial Band-7 family proteins: scaffolds for respiratory chain assembly? FRONTIERS IN PLANT SCIENCE 2014; 5:141. [PMID: 24782879 PMCID: PMC3986555 DOI: 10.3389/fpls.2014.00141] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2014] [Accepted: 03/24/2014] [Indexed: 05/28/2023]
Abstract
The band-7 protein family comprises a diverse set of membrane-bound proteins characterized by the presence of a conserved domain. The exact function of this band-7 domain remains elusive, but examples from animal and bacterial stomatin-type proteins demonstrate binding to lipids and the ability to assemble into membrane-bound oligomers that form putative scaffolds. Some members, such as prohibitins (PHB) and human stomatin-like protein 2 (HsSLP2), localize to the mitochondrial inner membrane where they function in cristae formation and hyperfusion. In Arabidopsis, the band-7 protein family has diversified and includes plant-specific members. Mitochondrial-localized members include prohibitins (AtPHBs) and two stomatin-like proteins (AtSLP1 and -2). Studies into PHB function in plants have demonstrated an involvement in root meristem proliferation and putative scaffold formation for mAAA proteases, but it remains unknown how these roles are achieved at the molecular level. In this minireview we summarize the current status of band-7 protein functions in Arabidopsis, and speculate how the mitochondrial members might recruit specific lipids to form microdomains that could shape the organization and functioning of the respiratory chain.
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Affiliation(s)
| | - Lee J. Sweetlove
- *Correspondence: Lee J. Sweetlove, Department of Plant Sciences, University of Oxford, South Parks Road, Oxford OX1 3RB, UK e-mail:
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