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Abstract
SIGNIFICANCE A wealth of fluorescent reporters and imaging systems are now available to characterize dynamic physiological processes in living cells with high spatiotemporal resolution. The most reliable probes for quantitative measurements show shifts in their excitation or emission spectrum, rather than just a change in intensity, as spectral shifts are independent of optical path length, illumination intensity, probe concentration, and photobleaching, and they can be easily determined by ratiometric measurements at two wavelengths. RECENT ADVANCES A number of ratiometric fluorescent reporters, such as reduction-oxidation-sensitive green fluorescent protein (roGFP), have been developed that respond to the glutathione redox potential and allow redox imaging in vivo. roGFP and its derivatives can be expressed in the cytoplasm or targeted to different organelles, giving fine control of measurements from sub-cellular compartments. Furthermore, roGFP can be imaged with probes for other physiological parameters, such as reactive oxygen species or mitochondrial membrane potential, to give multi-channel, multi-dimensional 4D (x,y,z,t) images. CRITICAL ISSUES Live cell imaging approaches are needed to capture transient or highly spatially localized physiological behavior from intact, living specimens, which are often not accessible by other biochemical or genetic means. FUTURE DIRECTIONS The next challenge is to be able to extract useful data rapidly from such large (GByte) images with due care given to the assumptions used during image processing. This article describes a suite of software programs, available for download, that provide intuitive user interfaces to conduct multi-channel ratio imaging, or alternative analysis methods such as pixel-population statistics or image segmentation and object-based ratio analysis. Antioxid. Redox Signal. 24, 752-762.
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Affiliation(s)
- Mark D Fricker
- Department of Plant Sciences, University of Oxford , Oxford, United Kingdom
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Schwarzländer M, Dick TP, Meyer AJ, Morgan B. Dissecting Redox Biology Using Fluorescent Protein Sensors. Antioxid Redox Signal 2016; 24:680-712. [PMID: 25867539 DOI: 10.1089/ars.2015.6266] [Citation(s) in RCA: 191] [Impact Index Per Article: 23.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
SIGNIFICANCE Fluorescent protein sensors have revitalized the field of redox biology by revolutionizing the study of redox processes in living cells and organisms. RECENT ADVANCES Within one decade, a set of fundamental new insights has been gained, driven by the rapid technical development of in vivo redox sensing. Redox-sensitive yellow and green fluorescent protein variants (rxYFP and roGFPs) have been the central players. CRITICAL ISSUES Although widely used as an established standard tool, important questions remain surrounding their meaningful use in vivo. We review the growing range of thiol redox sensor variants and their application in different cells, tissues, and organisms. We highlight five key findings where in vivo sensing has been instrumental in changing our understanding of redox biology, critically assess the interpretation of in vivo redox data, and discuss technical and biological limitations of current redox sensors and sensing approaches. FUTURE DIRECTIONS We explore how novel sensor variants may further add to the current momentum toward a novel mechanistic and integrated understanding of redox biology in vivo. Antioxid. Redox Signal. 24, 680-712.
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Affiliation(s)
- Markus Schwarzländer
- 1 Plant Energy Biology Lab, Department Chemical Signalling, Institute of Crop Science and Resource Conservation (INRES), University of Bonn , Bonn, Germany
| | - Tobias P Dick
- 2 Division of Redox Regulation, German Cancer Research Center (DKFZ) , DKFZ-ZMBH Alliance, Heidelberg, Germany
| | - Andreas J Meyer
- 3 Department Chemical Signalling, Institute of Crop Science and Resource Conservation (INRES), University of Bonn , Bonn, Germany
| | - Bruce Morgan
- 2 Division of Redox Regulation, German Cancer Research Center (DKFZ) , DKFZ-ZMBH Alliance, Heidelberg, Germany .,4 Cellular Biochemistry, Department of Biology, University of Kaiserslautern , Kaiserslautern, Germany
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53
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Carraretto L, Checchetto V, De Bortoli S, Formentin E, Costa A, Szabó I, Teardo E. Calcium Flux across Plant Mitochondrial Membranes: Possible Molecular Players. FRONTIERS IN PLANT SCIENCE 2016; 7:354. [PMID: 27065186 PMCID: PMC4814809 DOI: 10.3389/fpls.2016.00354] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/08/2015] [Accepted: 03/07/2016] [Indexed: 05/24/2023]
Abstract
Plants, being sessile organisms, have evolved the ability to integrate external stimuli into metabolic and developmental signals. A wide variety of signals, including abiotic, biotic, and developmental stimuli, were observed to evoke specific spatio-temporal Ca(2+) transients which are further transduced by Ca(2+) sensor proteins into a transcriptional and metabolic response. Most of the research on Ca(2+) signaling in plants has been focused on the transport mechanisms for Ca(2+) across the plasma- and the vacuolar membranes as well as on the components involved in decoding of cytoplasmic Ca(2+) signals, but how intracellular organelles such as mitochondria are involved in the process of Ca(2+) signaling is just emerging. The combination of the molecular players and the elicitors of Ca(2+) signaling in mitochondria together with newly generated detection systems for measuring organellar Ca(2+) concentrations in plants has started to provide fruitful grounds for further discoveries. In the present review we give an updated overview of the currently identified/hypothesized pathways, such as voltage-dependent anion channels, homologs of the mammalian mitochondrial uniporter (MCU), LETM1, a plant glutamate receptor family member, adenine nucleotide/phosphate carriers and the permeability transition pore (PTP), that may contribute to the transport of Ca(2+) across the outer and inner mitochondrial membranes in plants. We briefly discuss the relevance of the mitochondrial Ca(2+) homeostasis for ensuring optimal bioenergetic performance of this organelle.
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Affiliation(s)
| | - Vanessa Checchetto
- Department of Biology, University of PadovaPadova, Italy
- Department of Biomedical Sciences, University of PadovaPadova, Italy
| | | | - Elide Formentin
- Department of Biology, University of PadovaPadova, Italy
- Department of Life Science and Biotechnology, University of FerraraFerrara, Italy
| | - Alex Costa
- Department of Biosciences, University of MilanMilan, Italy
- CNR, Institute of Biophysics, Consiglio Nazionale delle RicercheMilan, Italy
| | - Ildikó Szabó
- Department of Biology, University of PadovaPadova, Italy
- CNR, Institute of NeurosciencesPadova, Italy
| | - Enrico Teardo
- Department of Biology, University of PadovaPadova, Italy
- CNR, Institute of NeurosciencesPadova, Italy
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Mitochondrial redox and pH signaling occurs in axonal and synaptic organelle clusters. Sci Rep 2016; 6:23251. [PMID: 27000952 PMCID: PMC4802380 DOI: 10.1038/srep23251] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2015] [Accepted: 03/02/2016] [Indexed: 01/09/2023] Open
Abstract
Redox switches are important mediators in neoplastic, cardiovascular and neurological disorders. We recently identified spontaneous redox signals in neurons at the single mitochondrion level where transients of glutathione oxidation go along with shortening and re-elongation of the organelle. We now have developed advanced image and signal-processing methods to re-assess and extend previously obtained data. Here we analyze redox and pH signals of entire mitochondrial populations. In total, we quantified the effects of 628 redox and pH events in 1797 mitochondria from intercostal axons and neuromuscular synapses using optical sensors (mito-Grx1-roGFP2; mito-SypHer). We show that neuronal mitochondria can undergo multiple redox cycles exhibiting markedly different signal characteristics compared to single redox events. Redox and pH events occur more often in mitochondrial clusters (medium cluster size: 34.1 ± 4.8 μm(2)). Local clusters possess higher mitochondrial densities than the rest of the axon, suggesting morphological and functional inter-mitochondrial coupling. We find that cluster formation is redox sensitive and can be blocked by the antioxidant MitoQ. In a nerve crush paradigm, mitochondrial clusters form sequentially adjacent to the lesion site and oxidation spreads between mitochondria. Our methodology combines optical bioenergetics and advanced signal processing and allows quantitative assessment of entire mitochondrial populations.
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55
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Checchetto V, Teardo E, Carraretto L, Leanza L, Szabo I. Physiology of intracellular potassium channels: A unifying role as mediators of counterion fluxes? BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2016; 1857:1258-1266. [PMID: 26970213 DOI: 10.1016/j.bbabio.2016.03.011] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/17/2016] [Revised: 03/06/2016] [Accepted: 03/07/2016] [Indexed: 12/28/2022]
Abstract
Plasma membrane potassium channels importantly contribute to maintain ion homeostasis across the cell membrane. The view is emerging that also those residing in intracellular membranes play pivotal roles for the coordination of correct cell function. In this review we critically discuss our current understanding of the nature and physiological tasks of potassium channels in organelle membranes in both animal and plant cells, with a special emphasis on their function in the regulation of photosynthesis and mitochondrial respiration. In addition, the emerging role of potassium channels in the nuclear membranes in regulating transcription will be discussed. The possible functions of endoplasmic reticulum-, lysosome- and plant vacuolar membrane-located channels are also referred to. Altogether, experimental evidence obtained with distinct channels in different membrane systems points to a possible unifying function of most intracellular potassium channels in counterbalancing the movement of other ions including protons and calcium and modulating membrane potential, thereby fine-tuning crucial cellular processes. This article is part of a Special Issue entitled 'EBEC 2016: 19th European Bioenergetics Conference, Riva del Garda, Italy, July 2-7, 2016', edited by Prof. Paolo Bernardi.
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Affiliation(s)
- Vanessa Checchetto
- Department of Biology, University of Padova, Viale G. Colombo 3, Padova 35131, Italy; Department of Biomedical Sciences, University of Padova, Viale G. Colombo 3, Padova 35131 Italy
| | - Enrico Teardo
- Department of Biology, University of Padova, Viale G. Colombo 3, Padova 35131, Italy
| | - Luca Carraretto
- Department of Biology, University of Padova, Viale G. Colombo 3, Padova 35131, Italy
| | - Luigi Leanza
- Department of Biology, University of Padova, Viale G. Colombo 3, Padova 35131, Italy
| | - Ildiko Szabo
- Department of Biology, University of Padova, Viale G. Colombo 3, Padova 35131, Italy; CNR Institute of Neuroscience, University of Padova, Viale G. Colombo 3, Padova 35131, Italy.
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56
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Hou T, Jian C, Xu J, Huang AY, Xi J, Hu K, Wei L, Cheng H, Wang X. Identification of EFHD1 as a novel Ca(2+) sensor for mitoflash activation. Cell Calcium 2016; 59:262-70. [PMID: 26975899 DOI: 10.1016/j.ceca.2016.03.002] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2015] [Revised: 02/23/2016] [Accepted: 03/02/2016] [Indexed: 01/16/2023]
Abstract
Mitochondrial flashes (mitoflashes) represent stochastic and discrete mitochondrial events that each comprises a burst of superoxide production accompanied by transient depolarization and matrix alkalinization in a respiratory mitochondrion. While mitochondrial Ca(2+) is shown to be an important regulator of mitoflash activity, little is known about its specific mechanism of action. Here we sought to determine possible molecular players that mediate the Ca(2+) regulation of mitoflashes by screening mitochondrial proteins containing the Ca(2+)-binding motifs. In silico analysis and targeted siRNA screening identified four mitoflash activators (MICU1, EFHD1, SLC25A23, SLC25A25) and one mitoflash inhibitor (LETM1) in terms of their ability to modulate mitoflash response to hyperosmotic stress. In particular, overexpression or down-regulation of EFHD1 enhanced or depressed mitoflash activation, respectively, under various conditions of mitochondrial Ca(2+) elevations. Yet, it did not alter mitochondrial Ca(2+) handling, mitochondrial respiration, or ROS-induced mitoflash production. Further, disruption of the two EF-hand motifs of EFHD1 abolished its potentiating effect on the mitoflash responses. These results indicate that EFHD1 functions as a novel mitochondrial Ca(2+) sensor underlying Ca(2+)-dependent activation of mitoflashes.
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Affiliation(s)
- Tingting Hou
- State Key Laboratory of Membrane Biology, Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Institute of Molecular Medicine, Peking-Tsinghua Center for Life Sciences, Peking University, Beijing, China
| | - Chongshu Jian
- State Key Laboratory of Membrane Biology, Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Institute of Molecular Medicine, Peking-Tsinghua Center for Life Sciences, Peking University, Beijing, China
| | - Jiejia Xu
- State Key Laboratory of Membrane Biology, Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Institute of Molecular Medicine, Peking-Tsinghua Center for Life Sciences, Peking University, Beijing, China
| | - August Yue Huang
- Center for Bioinformatics, State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences, Peking University, Beijing, China
| | - Jianzhong Xi
- State Key Laboratory of Membrane Biology, Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Institute of Molecular Medicine, Peking-Tsinghua Center for Life Sciences, Peking University, Beijing, China; Department of Biomedical Engineering, College of Engineering, Peking University, Beijing, China
| | - Keping Hu
- Research Center for Pharmacology and Toxicology, Institute of Medicinal Plant Development, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Liping Wei
- Center for Bioinformatics, State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences, Peking University, Beijing, China
| | - Heping Cheng
- State Key Laboratory of Membrane Biology, Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Institute of Molecular Medicine, Peking-Tsinghua Center for Life Sciences, Peking University, Beijing, China
| | - Xianhua Wang
- State Key Laboratory of Membrane Biology, Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Institute of Molecular Medicine, Peking-Tsinghua Center for Life Sciences, Peking University, Beijing, China.
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57
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Wagner S, Behera S, De Bortoli S, Logan DC, Fuchs P, Carraretto L, Teardo E, Cendron L, Nietzel T, Füßl M, Doccula FG, Navazio L, Fricker MD, Van Aken O, Finkemeier I, Meyer AJ, Szabò I, Costa A, Schwarzländer M. The EF-Hand Ca2+ Binding Protein MICU Choreographs Mitochondrial Ca2+ Dynamics in Arabidopsis. THE PLANT CELL 2015; 27:3190-212. [PMID: 26530087 PMCID: PMC4682298 DOI: 10.1105/tpc.15.00509] [Citation(s) in RCA: 77] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/10/2015] [Revised: 09/25/2015] [Accepted: 10/15/2015] [Indexed: 05/18/2023]
Abstract
Plant organelle function must constantly adjust to environmental conditions, which requires dynamic coordination. Ca(2+) signaling may play a central role in this process. Free Ca(2+) dynamics are tightly regulated and differ markedly between the cytosol, plastid stroma, and mitochondrial matrix. The mechanistic basis of compartment-specific Ca(2+) dynamics is poorly understood. Here, we studied the function of At-MICU, an EF-hand protein of Arabidopsis thaliana with homology to constituents of the mitochondrial Ca(2+) uniporter machinery in mammals. MICU binds Ca(2+) and localizes to the mitochondria in Arabidopsis. In vivo imaging of roots expressing a genetically encoded Ca(2+) sensor in the mitochondrial matrix revealed that lack of MICU increased resting concentrations of free Ca(2+) in the matrix. Furthermore, Ca(2+) elevations triggered by auxin and extracellular ATP occurred more rapidly and reached higher maximal concentrations in the mitochondria of micu mutants, whereas cytosolic Ca(2+) signatures remained unchanged. These findings support the idea that a conserved uniporter system, with composition and regulation distinct from the mammalian machinery, mediates mitochondrial Ca(2+) uptake in plants under in vivo conditions. They further suggest that MICU acts as a throttle that controls Ca(2+) uptake by moderating influx, thereby shaping Ca(2+) signatures in the matrix and preserving mitochondrial homeostasis. Our results open the door to genetic dissection of mitochondrial Ca(2+) signaling in plants.
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Affiliation(s)
- Stephan Wagner
- Plant Energy Biology Lab, Institute of Crop Science and Resource Conservation, University of Bonn, 53113 Bonn, Germany
| | | | - Sara De Bortoli
- Department of Biology, University of Padova, 35121 Padova, Italy
| | - David C Logan
- Université d'Angers, INRA, Agrocampus Ouest, UMR 1345 Institut de Recherche en Horticulture et Semences, F-49045 Angers, France
| | - Philippe Fuchs
- Plant Energy Biology Lab, Institute of Crop Science and Resource Conservation, University of Bonn, 53113 Bonn, Germany
| | - Luca Carraretto
- Department of Biology, University of Padova, 35121 Padova, Italy
| | - Enrico Teardo
- Department of Biology, University of Padova, 35121 Padova, Italy
| | - Laura Cendron
- Department of Biology, University of Padova, 35121 Padova, Italy
| | - Thomas Nietzel
- Plant Energy Biology Lab, Institute of Crop Science and Resource Conservation, University of Bonn, 53113 Bonn, Germany
| | - Magdalena Füßl
- Plant Proteomics Group, Max-Planck-Institute for Plant Breeding Research, 50829 Cologne, Germany
| | | | - Lorella Navazio
- Department of Biology, University of Padova, 35121 Padova, Italy
| | - Mark D Fricker
- Department of Plant Sciences, University of Oxford, Oxford OX1 3RB, United Kingdom
| | - Olivier Van Aken
- ARC Centre of Excellence in Plant Energy Biology, University of Western Australia, Crawley, WA 6009, Australia
| | - Iris Finkemeier
- Plant Proteomics Group, Max-Planck-Institute for Plant Breeding Research, 50829 Cologne, Germany Institute for Plant Biology and Biotechnology, University of Münster, 48149 Münster, Germany
| | - Andreas J Meyer
- Department Chemical Signalling, Institute of Crop Science and Resource Conservation, University of Bonn, 53113 Bonn, Germany
| | - Ildikò Szabò
- Department of Biology, University of Padova, 35121 Padova, Italy
| | - Alex Costa
- Department of Biosciences, University of Milan, 20133 Milan, Italy Institute of Biophysics, Consiglio Nazionale delle Ricerche, 20133 Milan, Italy
| | - Markus Schwarzländer
- Plant Energy Biology Lab, Institute of Crop Science and Resource Conservation, University of Bonn, 53113 Bonn, Germany
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58
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Fedyaeva AV, Stepanov AV, Lyubushkina IV, Pobezhimova TP, Rikhvanov EG. Heat shock induces production of reactive oxygen species and increases inner mitochondrial membrane potential in winter wheat cells. BIOCHEMISTRY (MOSCOW) 2015; 79:1202-10. [PMID: 25540005 DOI: 10.1134/s0006297914110078] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Heat shock leads to oxidative stress. Excessive ROS (reactive oxygen species) accumulation could be responsible for expression of genes of heat-shock proteins or for cell death. It is known that in isolated mammalian mitochondria high protonic potential on the inner membrane actuates the production of ROS. Changes in viability, ROS content, and mitochondrial membrane potential value have been studied in winter wheat (Triticum aestivum L.) cultured cells under heat treatment. Elevation of temperature to 37-50°C was found to induce elevated ROS generation and increased mitochondrial membrane potential, but it did not affect viability immediately after treatment. More severe heat exposure (55-60°C) was not accompanied by mitochondrial potential elevation and increased ROS production, but it led to instant cell death. A positive correlation between mitochondrial potential and ROS production was observed. Depolarization of the mitochondrial membrane by the protonophore CCCP inhibited ROS generation under the heating conditions. These data suggest that temperature elevation leads to mitochondrial membrane hyperpolarization in winter wheat cultured cells, which in turn causes the increased ROS production.
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Affiliation(s)
- A V Fedyaeva
- Siberian Institute of Plant Physiology and Biochemistry, Siberian Division of the Russian Academy of Sciences, Irkutsk, 664033, Russia.
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59
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Astrocyte sodium signaling and neuro-metabolic coupling in the brain. Neuroscience 2015; 323:121-34. [PMID: 25791228 DOI: 10.1016/j.neuroscience.2015.03.002] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2014] [Revised: 03/02/2015] [Accepted: 03/03/2015] [Indexed: 11/20/2022]
Abstract
At tripartite synapses, astrocytes undergo calcium signaling in response to release of neurotransmitters and this calcium signaling has been proposed to play a critical role in neuron-glia interaction. Recent work has now firmly established that, in addition, neuronal activity also evokes sodium transients in astrocytes, which can be local or global depending on the number of activated synapses and the duration of activity. Furthermore, astrocyte sodium signals can be transmitted to adjacent cells through gap junctions and following release of gliotransmitters. A main pathway for activity-related sodium influx into astrocytes is via high-affinity sodium-dependent glutamate transporters. Astrocyte sodium signals differ in many respects from the well-described glial calcium signals both in terms of their temporal as well as spatial distribution. There are no known buffering systems for sodium ions, nor is there store-mediated release of sodium. Sodium signals thus seem to represent rather direct and unbiased indicators of the site and strength of neuronal inputs. As such they have an immediate influence on the activity of sodium-dependent transporters which may even reverse in response to sodium signaling, as has been shown for GABA transporters for example. Furthermore, recovery from sodium transients through Na(+)/K(+)-ATPase requires a measurable amount of ATP, resulting in an activation of glial metabolism. In this review, we present basic principles of sodium regulation and the current state of knowledge concerning the occurrence and properties of activity-related sodium transients in astrocytes. We then discuss different aspects of the relationship between sodium changes in astrocytes and neuro-metabolic coupling, putting forward the idea that indeed sodium might serve as a new type of intracellular ion signal playing an important role in neuron-glia interaction and neuro-metabolic coupling in the healthy and diseased brain.
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60
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Wang Y, Li Y, Xue H, Pritchard HW, Wang X. Reactive oxygen species-provoked mitochondria-dependent cell death during ageing of elm (Ulmus pumila L.) seeds. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2015; 81:438-52. [PMID: 25439659 DOI: 10.1111/tpj.12737] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/28/2014] [Revised: 11/26/2014] [Accepted: 11/27/2014] [Indexed: 05/28/2023]
Abstract
Previous studies have shown that controlled deterioration treatment (CDT) induces programmed cell death in elm (Ulmus pumila L.) seeds, which undergo certain fundamental processes that are comparable to apoptosis in animals. In this study, the essential characteristics of mitochondrial physiology in elm seeds during CDT were identified by cellular ultrastructural analysis, whole-body optical imaging, Western blotting and semi-quantitative RT-PCR. The alteration in mitochondrial morphology was an early event during CDT, as indicated by progressive dynamic mitochondrial changes and rupture of the mitochondrial outer membrane; loss of mitochondrial transmembrane potential (Δψ(m)) ensued, and mitochondrial ATP levels decreased. The mitochondrial permeability transition pore inhibitor cyclosporine A effectively suppressed these changes during ageing. The in situ localization of production of reactive oxygen species (ROS), and evaluation of the expression of voltage-dependent anion-selective channel and cyclophilin D indicated that the levels of mitochondrial permeability transition pore components were positively correlated with ROS production, leading to an imbalance of the cellular redox potential and ultimately to programmed cell death. Pre-incubation with ascorbic acid slowed loss of mitochondrial Δψ(m), and decreased the effect of CDT on seed viability. However, there were no significant changes in multiple antioxidant elements or chaperones in the mitochondria during early stages of ageing. Our results indicate that CDT induces dynamic changes in mitochondrial physiology via increased ROS production, ultimately resulting in an irreversible loss of seed viability.
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Affiliation(s)
- Yu Wang
- National Engineering Laboratory for Tree Breeding, College of Biological Sciences and Biotechnology, Beijing Forestry University, 35 Tsinghua East Road, Beijing, China
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61
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Wagner S, Nietzel T, Aller I, Costa A, Fricker MD, Meyer AJ, Schwarzländer M. Analysis of plant mitochondrial function using fluorescent protein sensors. Methods Mol Biol 2015; 1305:241-52. [PMID: 25910739 DOI: 10.1007/978-1-4939-2639-8_17] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Mitochondrial physiology sets the basis for function of the organelle and vice versa. While a limited range of in vivo parameters, such as oxygen consumption, has been classically accessible for measurement, a growing collection of fluorescent protein sensors can now give insights into the physiology of plant mitochondria. Nevertheless, the meaningful application of these sensors in mitochondria is technically challenging and requires rigorous experimental standards. Here we exemplify the application of three genetically encoded sensors to monitor glutathione redox potential, pH, and calcium in the matrix of mitochondria in intact plants. We describe current methods for quantitative imaging and analysis in living root tips by confocal microscopy and discuss methodological limitations.
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Affiliation(s)
- Stephan Wagner
- Plant Energy Biology Lab, INRES - Chemical Signalling, University of Bonn, Bonn, 53113, Germany
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62
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Forlani G, Bertazzini M, Zarattini M, Funck D. Functional characterization and expression analysis of rice δ(1)-pyrroline-5-carboxylate dehydrogenase provide new insight into the regulation of proline and arginine catabolism. FRONTIERS IN PLANT SCIENCE 2015; 6:591. [PMID: 26300893 PMCID: PMC4525382 DOI: 10.3389/fpls.2015.00591] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/30/2015] [Accepted: 07/16/2015] [Indexed: 05/21/2023]
Abstract
While intracellular proline accumulation in response to various stress conditions has been investigated in great detail, the biochemistry and physiological relevance of proline degradation in plants is much less understood. Moreover, the second and last step in proline catabolism, the oxidation of δ(1)-pyrroline-5-carboxylic acid (P5C) to glutamate, is shared with arginine catabolism. Little information is available to date concerning the regulatory mechanisms coordinating these two pathways. Expression of the gene coding for P5C dehydrogenase was analyzed in rice by real-time PCR either following the exogenous supply of amino acids of the glutamate family, or under hyperosmotic stress conditions. The rice enzyme was heterologously expressed in E. coli, and the affinity-purified protein was thoroughly characterized with respect to structural and functional properties. A tetrameric oligomerization state was observed in size exclusion chromatography, which suggests a structure of the plant enzyme different from that shown for the bacterial P5C dehydrogenases structurally characterized to date. Kinetic analysis accounted for a preferential use of NAD(+) as the electron acceptor. Cations were found to modulate enzyme activity, whereas anion effects were negligible. Several metal ions were inhibitory in the micromolar range. Interestingly, arginine also inhibited the enzyme at higher concentrations, with a mechanism of uncompetitive type with respect to P5C. This implies that millimolar levels of arginine would increase the affinity of P5C dehydrogenase toward its specific substrate. Results are discussed in view of the involvement of the enzyme in either proline or arginine catabolism.
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Affiliation(s)
- Giuseppe Forlani
- Department of Life Science and Biotechnology, University of FerraraFerrara, Italy
- *Correspondence: Giuseppe Forlani, Laboratory of Plant Physiology and Biochemistry, Department of Life Science and Biotechnology, University of Ferrara, Via L. Borsari 46, Ferrara, 44121, Italy
| | - Michele Bertazzini
- Department of Life Science and Biotechnology, University of FerraraFerrara, Italy
- Biology Section, Department of Plant Physiology and Biochemistry, University of KonstanzKonstanz, Germany
| | - Marco Zarattini
- Department of Life Science and Biotechnology, University of FerraraFerrara, Italy
| | - Dietmar Funck
- Biology Section, Department of Plant Physiology and Biochemistry, University of KonstanzKonstanz, Germany
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63
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Pilkington SM, Encke B, Krohn N, Höhne M, Stitt M, Pyl ET. Relationship between starch degradation and carbon demand for maintenance and growth in Arabidopsis thaliana in different irradiance and temperature regimes. PLANT, CELL & ENVIRONMENT 2015; 38:157-71. [PMID: 24905937 DOI: 10.1111/pce.12381] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/04/2014] [Revised: 05/28/2014] [Accepted: 05/29/2014] [Indexed: 05/12/2023]
Abstract
Experiments were designed to compare the relationship between starch degradation and the use of carbon for maintenance and growth in Arabidopsis in source-limited and sink-limited conditions. It is known that starch degradation is regulated by the clock in source-limited plants, which degrade their starch in a linear manner such that it is almost but not completely exhausted at dawn. We asked whether this response is maintained under an extreme carbon deficit. Arabidopsis was subjected to a sudden combination of a day of low irradiance, to decrease starch at dusk, and a warm night. Starch was degraded in a linear manner through the night, even though the plants became acutely carbon starved. We conclude that starch degradation is not increased to meet demand in carbon-limited plants. This network property will allow stringent control of starch turnover in a fluctuating environment. In contrast, in sink-limited plants, which do not completely mobilize their starch during the night, starch degradation was accelerated in warm nights to meet the increased demand for maintenance and growth. Across all conditions, the rate of growth at night depends on the rate of starch degradation, whereas the rate of maintenance respiration decreases only when starch degradation is very slow.
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Affiliation(s)
- Sarah M Pilkington
- Max Planck Institute for Molecular Plant Physiology, Potsdam-Golm, 14476, Germany
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Zancani M, Casolo V, Petrussa E, Peresson C, Patui S, Bertolini A, De Col V, Braidot E, Boscutti F, Vianello A. The Permeability Transition in Plant Mitochondria: The Missing Link. FRONTIERS IN PLANT SCIENCE 2015; 6:1120. [PMID: 26697057 PMCID: PMC4678196 DOI: 10.3389/fpls.2015.01120] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/30/2015] [Accepted: 11/26/2015] [Indexed: 05/17/2023]
Abstract
The synthesis of ATP in mitochondria is dependent on a low permeability of the inner membrane. Nevertheless, mitochondria can undergo an increased permeability to solutes, named permeability transition (PT) that is mediated by a permeability transition pore (PTP). PTP opening requires matrix Ca(2+) and leads to mitochondrial swelling and release of intramembrane space proteins (e.g., cytochrome c). This feature has been initially observed in mammalian mitochondria and tentatively attributed to some components present either in the outer or inner membrane. Recent works on mammalian mitochondria point to mitochondrial ATP synthase dimers as physical basis for PT, a finding that has been substantiated in yeast and Drosophila mitochondria. In plant mitochondria, swelling and release of proteins have been linked to programmed cell death, but in isolated mitochondria PT has been observed in only a few cases and in plant cell cultures only indirect evidence is available. The possibility that mitochondrial ATP synthase dimers could function as PTP also in plants is discussed here on the basis of the current evidence. Finally, a hypothetical explanation for the origin of PTP is provided in the framework of molecular exaptation.
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Vajrala VS, Suraniti E, Goudeau B, Sojic N, Arbault S. Optical microwell arrays for large-scale studies of single mitochondria metabolic responses. Methods Mol Biol 2015; 1264:47-58. [PMID: 25631002 DOI: 10.1007/978-1-4939-2257-4_5] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Most of the methods dedicated to the monitoring of metabolic responses from isolated mitochondria are based on whole-population analyses. They rarely offer an individual resolution though fluorescence microscopy allows it, as demonstrated by numerous studies on single mitochondria activities in cells. Herein, we report on the preparation and use of microwell arrays for the entrapment and fluorescence microscopy of single isolated mitochondria. Highly dense arrays of 3 μm mean diameter wells were obtained by the chemical etching of optical fiber bundles (850 μm whole diameter). They were manipulated by a micro-positioner and placed in a chamber made of a biocompatible elastomer (polydimethylsiloxane or PDMS) and a glass coverslip, on the platform of an inverted microscope. The stable entrapment of individual mitochondria (extracted from Saccharomyces cerevisiae yeast strains, inter alia, expressing a green fluorescent protein) within the microwells was obtained by pretreating the optical bundles with an oxygen plasma and dipping the hydrophilic surface of the array in a concentrated solution of mitochondria. Based on the measurement of variations of the intrinsic NADH fluorescence of each mitochondrion in the array, their metabolic status was analyzed at different energetic respiratory stages: under resting state, following the addition of an energetic substrate to stimulate respiration (ethanol herein) and the addition of a respiratory inhibitor (antimycin A). Statistical analyses of mean variations of mitochondrial NADH in the population were subsequently achieved with a single organelle resolution.
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Affiliation(s)
- Venkata Suresh Vajrala
- ISM, CNRS UMR 5255, ENSCBP, University of Bordeaux, 16 avenue Pey Berland, 33607, Pessac, France
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Schwarzländer M, Wagner S, Ermakova YG, Belousov VV, Radi R, Beckman JS, Buettner GR, Demaurex N, Duchen MR, Forman HJ, Fricker MD, Gems D, Halestrap AP, Halliwell B, Jakob U, Johnston IG, Jones NS, Logan DC, Morgan B, Müller FL, Nicholls DG, Remington SJ, Schumacker PT, Winterbourn CC, Sweetlove LJ, Meyer AJ, Dick TP, Murphy MP. The 'mitoflash' probe cpYFP does not respond to superoxide. Nature 2014; 514:E12-4. [PMID: 25341790 DOI: 10.1038/nature13858] [Citation(s) in RCA: 104] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2014] [Accepted: 08/28/2014] [Indexed: 01/08/2023]
Affiliation(s)
- Markus Schwarzländer
- Institute of Crop Science and Resource Conservation (INRES), University of Bonn, Friedrich-Ebert-Allee 144, 53113 Bonn, Germany
| | - Stephan Wagner
- Institute of Crop Science and Resource Conservation (INRES), University of Bonn, Friedrich-Ebert-Allee 144, 53113 Bonn, Germany
| | - Yulia G Ermakova
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, 117997, Russia
| | - Vsevolod V Belousov
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, 117997, Russia
| | - Rafael Radi
- Departamento de Bioquímica, and Center for Free Radical and Biomedical Research, Facultad de Medicina, Universidad de la República, Avda. General Flores 2125, 11800 Montevideo, Uruguay
| | - Joseph S Beckman
- Linus Pauling Institute, Environmental Health Sciences Center, Department of Biochemistry and Biophysics, Oregon State University, Corvallis, Oregon 97331, USA
| | - Garry R Buettner
- The University of Iowa, Department of Radiation Oncology and Interdisciplinary Graduate Program in Human Toxicology, and ESR Facility, College of Medicine, Med Labs B180K, Iowa City, Iowa 52242-1181, USA
| | - Nicolas Demaurex
- Department of Cell Physiology and Metabolism, University of Geneva, 1, rue Michel-Servet, Geneva 4 CH-1211, Switzerland
| | - Michael R Duchen
- Department of Cell and Developmental Biology and Consortium for Mitochondrial Research, University College London, Gower Street, London WC1E 6BT, UK
| | - Henry J Forman
- 1] Life and Environmental Sciences Unit, University of California, Merced, 5200 North Lake Road, Merced, California 95344, USA [2] Andrus Gerontology Center of the Davis School of Gerontology, University of Southern California, 3715 McClintock Avenue, Los Angeles, California 90089-0191, USA
| | - Mark D Fricker
- Department of Plant Sciences, University of Oxford, South Parks Road, Oxford OX1 3RB, UK
| | - David Gems
- Institute of Healthy Ageing, and Department of Genetics, Evolution and Environment, University College London, London WC1E 6BT, UK
| | - Andrew P Halestrap
- School of Biochemistry and Bristol CardioVascular, University of Bristol, Medical Sciences Building, University Walk, Bristol BS8 1TD, UK
| | - Barry Halliwell
- Department of Biochemistry, National University of Singapore, Singapore 117597, Singapore
| | - Ursula Jakob
- Molecular, Cellular and Developmental Biology Department, University of Michigan, Ann Arbor, Michigan 48109-1048, USA
| | - Iain G Johnston
- Department of Mathematics, South Kensington Campus, Imperial College London, London SW7 2AZ, UK
| | - Nick S Jones
- Department of Mathematics, South Kensington Campus, Imperial College London, London SW7 2AZ, UK
| | - David C Logan
- Université d'Angers &INRA &Agrocampus Ouest, UMR 1345 Institut de Recherche en Horticulture et Semences, Angers, F-49045, France
| | - Bruce Morgan
- Division of Redox Regulation, German Cancer Research Center (DKFZ), DKFZ-ZMBH Alliance, Im Neuenheimer Feld 280, 69120 Heidelberg, Germany
| | - Florian L Müller
- Department of Cancer Biology, University of Texas MD Anderson Cancer Center, Houston, Texas 77030, USA
| | - David G Nicholls
- Buck Institute for Research on Aging, 8001 Redwood Boulevard, Novato, California 94945, USA
| | - S James Remington
- Department of Physics, Institute of Molecular Biology, University of Oregon, Eugene, Oregon 97403-1229, USA
| | - Paul T Schumacker
- Department of Pediatrics, Division of Neonatology, Northwestern University, Feinberg School of Medicine, Chicago, Illinois, 60611, USA
| | - Christine C Winterbourn
- Centre for Free Radical Research, Department of Pathology, University of Otago, ChristchurchPO Box 4345, Christchurch, New Zealand
| | - Lee J Sweetlove
- Department of Plant Sciences, University of Oxford, South Parks Road, Oxford OX1 3RB, UK
| | - Andreas J Meyer
- Institute of Crop Science and Resource Conservation (INRES), University of Bonn, Friedrich-Ebert-Allee 144, 53113 Bonn, Germany
| | - Tobias P Dick
- Division of Redox Regulation, German Cancer Research Center (DKFZ), DKFZ-ZMBH Alliance, Im Neuenheimer Feld 280, 69120 Heidelberg, Germany
| | - Michael P Murphy
- MRC Mitochondrial Biology Unit, Hills Road, Cambridge CB2 0XY, UK
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Murcha MW, Kmiec B, Kubiszewski-Jakubiak S, Teixeira PF, Glaser E, Whelan J. Protein import into plant mitochondria: signals, machinery, processing, and regulation. JOURNAL OF EXPERIMENTAL BOTANY 2014; 65:6301-35. [PMID: 25324401 DOI: 10.1093/jxb/eru399] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
The majority of more than 1000 proteins present in mitochondria are imported from nuclear-encoded, cytosolically synthesized precursor proteins. This impressive feat of transport and sorting is achieved by the combined action of targeting signals on mitochondrial proteins and the mitochondrial protein import apparatus. The mitochondrial protein import apparatus is composed of a number of multi-subunit protein complexes that recognize, translocate, and assemble mitochondrial proteins into functional complexes. While the core subunits involved in mitochondrial protein import are well conserved across wide phylogenetic gaps, the accessory subunits of these complexes differ in identity and/or function when plants are compared with Saccharomyces cerevisiae (yeast), the model system for mitochondrial protein import. These differences include distinct protein import receptors in plants, different mechanistic operation of the intermembrane protein import system, the location and activity of peptidases, the function of inner-membrane translocases in linking the outer and inner membrane, and the association/regulation of mitochondrial protein import complexes with components of the respiratory chain. Additionally, plant mitochondria share proteins with plastids, i.e. dual-targeted proteins. Also, the developmental and cell-specific nature of mitochondrial biogenesis is an aspect not observed in single-celled systems that is readily apparent in studies in plants. This means that plants provide a valuable model system to study the various regulatory processes associated with protein import and mitochondrial biogenesis.
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Affiliation(s)
- Monika W Murcha
- Australian Research Council Centre of Excellence in Plant Energy Biology, University of Western Australia, 35 Stirling Highway, Crawley, Western Australia, 6009, Australia
| | - Beata Kmiec
- Department of Biochemistry and Biophysics, Stockholm University, Arrhenius Laboratories for Natural Sciences, SE-10691 Stockholm, Sweden
| | - Szymon Kubiszewski-Jakubiak
- Australian Research Council Centre of Excellence in Plant Energy Biology, University of Western Australia, 35 Stirling Highway, Crawley, Western Australia, 6009, Australia
| | - Pedro F Teixeira
- Department of Biochemistry and Biophysics, Stockholm University, Arrhenius Laboratories for Natural Sciences, SE-10691 Stockholm, Sweden
| | - Elzbieta Glaser
- Department of Biochemistry and Biophysics, Stockholm University, Arrhenius Laboratories for Natural Sciences, SE-10691 Stockholm, Sweden
| | - James Whelan
- Australian Research Council Centre of Excellence in Plant Energy Biology, School of Life Science, La Trobe University, Bundoora, Victoria, 3086, Australia
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El Zawily AM, Schwarzländer M, Finkemeier I, Johnston IG, Benamar A, Cao Y, Gissot C, Meyer AJ, Wilson K, Datla R, Macherel D, Jones NS, Logan DC. FRIENDLY regulates mitochondrial distribution, fusion, and quality control in Arabidopsis. PLANT PHYSIOLOGY 2014; 166:808-28. [PMID: 25165398 PMCID: PMC4213110 DOI: 10.1104/pp.114.243824] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/27/2014] [Accepted: 08/27/2014] [Indexed: 05/19/2023]
Abstract
Mitochondria are defining components of most eukaryotes. However, higher plant mitochondria differ biochemically, morphologically, and dynamically from those in other eukaryotes. FRIENDLY, a member of the CLUSTERED MITOCHONDRIA superfamily, is conserved among eukaryotes and is required for correct distribution of mitochondria within the cell. We sought to understand how disruption of FRIENDLY function in Arabidopsis (Arabidopsis thaliana) leads to mitochondrial clustering and the effects of this aberrant chondriome on cell and whole-plant physiology. We present evidence for a role of FRIENDLY in mediating intermitochondrial association, which is a necessary prelude to mitochondrial fusion. We demonstrate that disruption of mitochondrial association, motility, and chondriome structure in friendly affects mitochondrial quality control and leads to mitochondrial stress, cell death, and strong growth phenotypes.
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Affiliation(s)
- Amr M El Zawily
- Department of Biology, University of Saskatchewan, Saskatoon, Saskatchewan, Canada S7N 5E2 (A.M.E.Z., K.W., D.C.L.);Faculty of Science, Damanhour University, Damanhour 22516, Egypt (A.M.E.Z.);Institute of Crop Science and Resource Conservation, University of Bonn, D-53113 Bonn, Germany (M.S., A.J.M.);Max-Planck-Institute for Plant Breeding Research, Plant Proteomics Group, 50829 Cologne, Germany (I.F.);Department of Mathematics, Imperial College London, London SW7 2AZ, United Kingdom (I.G.J., C.G., N.S.J.);Université d'Angers, Institut National de la Recherche Agronomique, and Agrocampus Ouest, Unité Mixte de Recherche 1345, Institut de Recherche en Horticulture et Semences, Angers F-49045, France (A.B., D.M., D.C.L.); andPlant Biotechnology Institute, National Research Council of Canada, Saskatoon, Saskatchewan S7N 0W9, Canada (Y.C., R.D.)
| | - Markus Schwarzländer
- Department of Biology, University of Saskatchewan, Saskatoon, Saskatchewan, Canada S7N 5E2 (A.M.E.Z., K.W., D.C.L.);Faculty of Science, Damanhour University, Damanhour 22516, Egypt (A.M.E.Z.);Institute of Crop Science and Resource Conservation, University of Bonn, D-53113 Bonn, Germany (M.S., A.J.M.);Max-Planck-Institute for Plant Breeding Research, Plant Proteomics Group, 50829 Cologne, Germany (I.F.);Department of Mathematics, Imperial College London, London SW7 2AZ, United Kingdom (I.G.J., C.G., N.S.J.);Université d'Angers, Institut National de la Recherche Agronomique, and Agrocampus Ouest, Unité Mixte de Recherche 1345, Institut de Recherche en Horticulture et Semences, Angers F-49045, France (A.B., D.M., D.C.L.); andPlant Biotechnology Institute, National Research Council of Canada, Saskatoon, Saskatchewan S7N 0W9, Canada (Y.C., R.D.)
| | - Iris Finkemeier
- Department of Biology, University of Saskatchewan, Saskatoon, Saskatchewan, Canada S7N 5E2 (A.M.E.Z., K.W., D.C.L.);Faculty of Science, Damanhour University, Damanhour 22516, Egypt (A.M.E.Z.);Institute of Crop Science and Resource Conservation, University of Bonn, D-53113 Bonn, Germany (M.S., A.J.M.);Max-Planck-Institute for Plant Breeding Research, Plant Proteomics Group, 50829 Cologne, Germany (I.F.);Department of Mathematics, Imperial College London, London SW7 2AZ, United Kingdom (I.G.J., C.G., N.S.J.);Université d'Angers, Institut National de la Recherche Agronomique, and Agrocampus Ouest, Unité Mixte de Recherche 1345, Institut de Recherche en Horticulture et Semences, Angers F-49045, France (A.B., D.M., D.C.L.); andPlant Biotechnology Institute, National Research Council of Canada, Saskatoon, Saskatchewan S7N 0W9, Canada (Y.C., R.D.)
| | - Iain G Johnston
- Department of Biology, University of Saskatchewan, Saskatoon, Saskatchewan, Canada S7N 5E2 (A.M.E.Z., K.W., D.C.L.);Faculty of Science, Damanhour University, Damanhour 22516, Egypt (A.M.E.Z.);Institute of Crop Science and Resource Conservation, University of Bonn, D-53113 Bonn, Germany (M.S., A.J.M.);Max-Planck-Institute for Plant Breeding Research, Plant Proteomics Group, 50829 Cologne, Germany (I.F.);Department of Mathematics, Imperial College London, London SW7 2AZ, United Kingdom (I.G.J., C.G., N.S.J.);Université d'Angers, Institut National de la Recherche Agronomique, and Agrocampus Ouest, Unité Mixte de Recherche 1345, Institut de Recherche en Horticulture et Semences, Angers F-49045, France (A.B., D.M., D.C.L.); andPlant Biotechnology Institute, National Research Council of Canada, Saskatoon, Saskatchewan S7N 0W9, Canada (Y.C., R.D.)
| | - Abdelilah Benamar
- Department of Biology, University of Saskatchewan, Saskatoon, Saskatchewan, Canada S7N 5E2 (A.M.E.Z., K.W., D.C.L.);Faculty of Science, Damanhour University, Damanhour 22516, Egypt (A.M.E.Z.);Institute of Crop Science and Resource Conservation, University of Bonn, D-53113 Bonn, Germany (M.S., A.J.M.);Max-Planck-Institute for Plant Breeding Research, Plant Proteomics Group, 50829 Cologne, Germany (I.F.);Department of Mathematics, Imperial College London, London SW7 2AZ, United Kingdom (I.G.J., C.G., N.S.J.);Université d'Angers, Institut National de la Recherche Agronomique, and Agrocampus Ouest, Unité Mixte de Recherche 1345, Institut de Recherche en Horticulture et Semences, Angers F-49045, France (A.B., D.M., D.C.L.); andPlant Biotechnology Institute, National Research Council of Canada, Saskatoon, Saskatchewan S7N 0W9, Canada (Y.C., R.D.)
| | - Yongguo Cao
- Department of Biology, University of Saskatchewan, Saskatoon, Saskatchewan, Canada S7N 5E2 (A.M.E.Z., K.W., D.C.L.);Faculty of Science, Damanhour University, Damanhour 22516, Egypt (A.M.E.Z.);Institute of Crop Science and Resource Conservation, University of Bonn, D-53113 Bonn, Germany (M.S., A.J.M.);Max-Planck-Institute for Plant Breeding Research, Plant Proteomics Group, 50829 Cologne, Germany (I.F.);Department of Mathematics, Imperial College London, London SW7 2AZ, United Kingdom (I.G.J., C.G., N.S.J.);Université d'Angers, Institut National de la Recherche Agronomique, and Agrocampus Ouest, Unité Mixte de Recherche 1345, Institut de Recherche en Horticulture et Semences, Angers F-49045, France (A.B., D.M., D.C.L.); andPlant Biotechnology Institute, National Research Council of Canada, Saskatoon, Saskatchewan S7N 0W9, Canada (Y.C., R.D.)
| | - Clémence Gissot
- Department of Biology, University of Saskatchewan, Saskatoon, Saskatchewan, Canada S7N 5E2 (A.M.E.Z., K.W., D.C.L.);Faculty of Science, Damanhour University, Damanhour 22516, Egypt (A.M.E.Z.);Institute of Crop Science and Resource Conservation, University of Bonn, D-53113 Bonn, Germany (M.S., A.J.M.);Max-Planck-Institute for Plant Breeding Research, Plant Proteomics Group, 50829 Cologne, Germany (I.F.);Department of Mathematics, Imperial College London, London SW7 2AZ, United Kingdom (I.G.J., C.G., N.S.J.);Université d'Angers, Institut National de la Recherche Agronomique, and Agrocampus Ouest, Unité Mixte de Recherche 1345, Institut de Recherche en Horticulture et Semences, Angers F-49045, France (A.B., D.M., D.C.L.); andPlant Biotechnology Institute, National Research Council of Canada, Saskatoon, Saskatchewan S7N 0W9, Canada (Y.C., R.D.)
| | - Andreas J Meyer
- Department of Biology, University of Saskatchewan, Saskatoon, Saskatchewan, Canada S7N 5E2 (A.M.E.Z., K.W., D.C.L.);Faculty of Science, Damanhour University, Damanhour 22516, Egypt (A.M.E.Z.);Institute of Crop Science and Resource Conservation, University of Bonn, D-53113 Bonn, Germany (M.S., A.J.M.);Max-Planck-Institute for Plant Breeding Research, Plant Proteomics Group, 50829 Cologne, Germany (I.F.);Department of Mathematics, Imperial College London, London SW7 2AZ, United Kingdom (I.G.J., C.G., N.S.J.);Université d'Angers, Institut National de la Recherche Agronomique, and Agrocampus Ouest, Unité Mixte de Recherche 1345, Institut de Recherche en Horticulture et Semences, Angers F-49045, France (A.B., D.M., D.C.L.); andPlant Biotechnology Institute, National Research Council of Canada, Saskatoon, Saskatchewan S7N 0W9, Canada (Y.C., R.D.)
| | - Ken Wilson
- Department of Biology, University of Saskatchewan, Saskatoon, Saskatchewan, Canada S7N 5E2 (A.M.E.Z., K.W., D.C.L.);Faculty of Science, Damanhour University, Damanhour 22516, Egypt (A.M.E.Z.);Institute of Crop Science and Resource Conservation, University of Bonn, D-53113 Bonn, Germany (M.S., A.J.M.);Max-Planck-Institute for Plant Breeding Research, Plant Proteomics Group, 50829 Cologne, Germany (I.F.);Department of Mathematics, Imperial College London, London SW7 2AZ, United Kingdom (I.G.J., C.G., N.S.J.);Université d'Angers, Institut National de la Recherche Agronomique, and Agrocampus Ouest, Unité Mixte de Recherche 1345, Institut de Recherche en Horticulture et Semences, Angers F-49045, France (A.B., D.M., D.C.L.); andPlant Biotechnology Institute, National Research Council of Canada, Saskatoon, Saskatchewan S7N 0W9, Canada (Y.C., R.D.)
| | - Raju Datla
- Department of Biology, University of Saskatchewan, Saskatoon, Saskatchewan, Canada S7N 5E2 (A.M.E.Z., K.W., D.C.L.);Faculty of Science, Damanhour University, Damanhour 22516, Egypt (A.M.E.Z.);Institute of Crop Science and Resource Conservation, University of Bonn, D-53113 Bonn, Germany (M.S., A.J.M.);Max-Planck-Institute for Plant Breeding Research, Plant Proteomics Group, 50829 Cologne, Germany (I.F.);Department of Mathematics, Imperial College London, London SW7 2AZ, United Kingdom (I.G.J., C.G., N.S.J.);Université d'Angers, Institut National de la Recherche Agronomique, and Agrocampus Ouest, Unité Mixte de Recherche 1345, Institut de Recherche en Horticulture et Semences, Angers F-49045, France (A.B., D.M., D.C.L.); andPlant Biotechnology Institute, National Research Council of Canada, Saskatoon, Saskatchewan S7N 0W9, Canada (Y.C., R.D.)
| | - David Macherel
- Department of Biology, University of Saskatchewan, Saskatoon, Saskatchewan, Canada S7N 5E2 (A.M.E.Z., K.W., D.C.L.);Faculty of Science, Damanhour University, Damanhour 22516, Egypt (A.M.E.Z.);Institute of Crop Science and Resource Conservation, University of Bonn, D-53113 Bonn, Germany (M.S., A.J.M.);Max-Planck-Institute for Plant Breeding Research, Plant Proteomics Group, 50829 Cologne, Germany (I.F.);Department of Mathematics, Imperial College London, London SW7 2AZ, United Kingdom (I.G.J., C.G., N.S.J.);Université d'Angers, Institut National de la Recherche Agronomique, and Agrocampus Ouest, Unité Mixte de Recherche 1345, Institut de Recherche en Horticulture et Semences, Angers F-49045, France (A.B., D.M., D.C.L.); andPlant Biotechnology Institute, National Research Council of Canada, Saskatoon, Saskatchewan S7N 0W9, Canada (Y.C., R.D.)
| | - Nick S Jones
- Department of Biology, University of Saskatchewan, Saskatoon, Saskatchewan, Canada S7N 5E2 (A.M.E.Z., K.W., D.C.L.);Faculty of Science, Damanhour University, Damanhour 22516, Egypt (A.M.E.Z.);Institute of Crop Science and Resource Conservation, University of Bonn, D-53113 Bonn, Germany (M.S., A.J.M.);Max-Planck-Institute for Plant Breeding Research, Plant Proteomics Group, 50829 Cologne, Germany (I.F.);Department of Mathematics, Imperial College London, London SW7 2AZ, United Kingdom (I.G.J., C.G., N.S.J.);Université d'Angers, Institut National de la Recherche Agronomique, and Agrocampus Ouest, Unité Mixte de Recherche 1345, Institut de Recherche en Horticulture et Semences, Angers F-49045, France (A.B., D.M., D.C.L.); andPlant Biotechnology Institute, National Research Council of Canada, Saskatoon, Saskatchewan S7N 0W9, Canada (Y.C., R.D.)
| | - David C Logan
- Department of Biology, University of Saskatchewan, Saskatoon, Saskatchewan, Canada S7N 5E2 (A.M.E.Z., K.W., D.C.L.);Faculty of Science, Damanhour University, Damanhour 22516, Egypt (A.M.E.Z.);Institute of Crop Science and Resource Conservation, University of Bonn, D-53113 Bonn, Germany (M.S., A.J.M.);Max-Planck-Institute for Plant Breeding Research, Plant Proteomics Group, 50829 Cologne, Germany (I.F.);Department of Mathematics, Imperial College London, London SW7 2AZ, United Kingdom (I.G.J., C.G., N.S.J.);Université d'Angers, Institut National de la Recherche Agronomique, and Agrocampus Ouest, Unité Mixte de Recherche 1345, Institut de Recherche en Horticulture et Semences, Angers F-49045, France (A.B., D.M., D.C.L.); andPlant Biotechnology Institute, National Research Council of Canada, Saskatoon, Saskatchewan S7N 0W9, Canada (Y.C., R.D.)
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Dumont J, Cohen D, Gérard J, Jolivet Y, Dizengremel P, LE Thiec D. Distinct responses to ozone of abaxial and adaxial stomata in three Euramerican poplar genotypes. PLANT, CELL & ENVIRONMENT 2014; 37:2064-2076. [PMID: 24506578 DOI: 10.1111/pce.12293] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/29/2013] [Revised: 01/16/2014] [Accepted: 01/21/2014] [Indexed: 06/03/2023]
Abstract
Ozone induces stomatal sluggishness, which impacts photosynthesis and transpiration. Stomatal responses to variation of environmental parameters are slowed and reduced by ozone and may be linked to difference of ozone sensitivity. Here we determine the ozone effects on stomatal conductance of each leaf surface. Potential causes of this sluggish movement, such as ultrastructural or ionic fluxes modification, were studied independently on both leaf surfaces of three Euramerican poplar genotypes differing in ozone sensitivity and in stomatal behaviour. The element contents in guard cells were linked to the gene expression of ion channels and transporters involved in stomatal movements, directly in microdissected stomata. In response to ozone, we found a decrease in the stomatal conductance of the leaf adaxial surface correlated with high calcium content in guard cells compared with a slight decrease on the abaxial surface. No ultrastructural modifications of stomata were shown except an increase in the number of mitochondria. The expression of vacuolar H(+) /Ca(2+) -antiports (CAX1 and CAX3 homologs), β-carbonic anhydrases (βCA1 and βCA4) and proton H(+) -ATPase (AHA11) genes was strongly decreased under ozone treatment. The sensitive genotype characterized by constitutive slow stomatal response was also characterized by constitutive low expression of genes encoding vacuolar H(+) /Ca(2+) -antiports.
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Affiliation(s)
- Jennifer Dumont
- INRA, UMR 1137, Ecologie et Ecophysiologie Forestières, Champenoux, F-54280, France; Université de Lorraine, UMR 1137, Ecologie et Ecophysiologie Forestières, Vandoeuvre-lès-Nancy, F-54500, France; IFR110 EFABA, Vandoeuvre-lès-Nancy, F-54500, France
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Hou T, Wang X, Ma Q, Cheng H. Mitochondrial flashes: new insights into mitochondrial ROS signalling and beyond. J Physiol 2014; 592:3703-13. [PMID: 25038239 DOI: 10.1113/jphysiol.2014.275735] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Respiratory mitochondria undergo stochastic, intermittent bursts of superoxide production accompanied by transient depolarization of the mitochondrial membrane potential and reversible opening of the membrane permeability transition pore. These discrete events were named 'superoxide flashes' for the reactive oxygen species (ROS) signal involved, and 'mitochondrial flashes' (mitoflashes) for the entirety of the multifaceted and intertwined mitochondrial processes. In contrast to the flashless basal ROS production of 'homeostatic ROS' for redox regulation, bursting ROS production during mitoflashes may provide 'signalling ROS' at the organelle level, fulfilling distinctly different cell functions. Mounting evidence indicates that mitoflash frequency is richly regulated over a broad range, and represents a novel, universal, and 'digital' readout of mitochondrial functional status and of the mitochondrial stress response. An emerging view is that mitoflashes participate in vital processes including metabolism, cell differentiation, the stress response and ageing. These recent advances shed new light on the role of mitochondrial functional dynamics in health and disease.
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Affiliation(s)
- Tingting Hou
- State Key Laboratory of Biomembrane and Membrane Biotechnology, Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Institute of Molecular Medicine, Peking-Tsinghua Center for Life Sciences, Peking University, Beijing, 100871, China
| | - Xianhua Wang
- State Key Laboratory of Biomembrane and Membrane Biotechnology, Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Institute of Molecular Medicine, Peking-Tsinghua Center for Life Sciences, Peking University, Beijing, 100871, China
| | - Qi Ma
- State Key Laboratory of Biomembrane and Membrane Biotechnology, Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Institute of Molecular Medicine, Peking-Tsinghua Center for Life Sciences, Peking University, Beijing, 100871, China
| | - Heping Cheng
- State Key Laboratory of Biomembrane and Membrane Biotechnology, Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Institute of Molecular Medicine, Peking-Tsinghua Center for Life Sciences, Peking University, Beijing, 100871, China
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72
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Ng S, De Clercq I, Van Aken O, Law SR, Ivanova A, Willems P, Giraud E, Van Breusegem F, Whelan J. Anterograde and retrograde regulation of nuclear genes encoding mitochondrial proteins during growth, development, and stress. MOLECULAR PLANT 2014; 7:1075-93. [PMID: 24711293 DOI: 10.1093/mp/ssu037] [Citation(s) in RCA: 120] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Mitochondrial biogenesis and function in plants require the expression of over 1000 nuclear genes encoding mitochondrial proteins (NGEMPs). The expression of these genes is regulated by tissue-specific, developmental, internal, and external stimuli that result in a dynamic organelle involved in both metabolic and a variety of signaling processes. Although the metabolic and biosynthetic machinery of mitochondria is relatively well understood, the factors that regulate these processes and the various signaling pathways involved are only beginning to be identified at a molecular level. The molecular components of anterograde (nuclear to mitochondrial) and retrograde (mitochondrial to nuclear) signaling pathways that regulate the expression of NGEMPs interact with chloroplast-, growth-, and stress-signaling pathways in the cell at a variety of levels, with common components involved in transmission and execution of these signals. This positions mitochondria as important hubs for signaling in the cell, not only in direct signaling of mitochondrial function per se, but also in sensing and/or integrating a variety of other internal and external signals. This integrates and optimizes growth with energy metabolism and stress responses, which is required in both photosynthetic and non-photosynthetic cells.
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Affiliation(s)
- Sophia Ng
- ARC Centre of Excellence in Plant Energy Biology, University of Western Australia, Australia Joint Research Laboratory in Genomics and Nutriomics, College of Life Sciences, Zhejiang University, Hangzhou, 310058, P.R. China
| | - Inge De Clercq
- Department of Plant Systems Biology, VIB, and Department of Plant Biotechnology and Bioinformatics, Ghent University, Technologiepark 927, B-9052 Gent, Belgium
| | - Olivier Van Aken
- ARC Centre of Excellence in Plant Energy Biology, University of Western Australia, Australia
| | - Simon R Law
- Department of Botany, ARC Centre of Excellence in Plant Energy Biology, School of Life Science, La Trobe University, Bundoora 3086, Victoria, Australia
| | - Aneta Ivanova
- Department of Botany, ARC Centre of Excellence in Plant Energy Biology, School of Life Science, La Trobe University, Bundoora 3086, Victoria, Australia
| | - Patrick Willems
- Department of Plant Systems Biology, VIB, and Department of Plant Biotechnology and Bioinformatics, Ghent University, Technologiepark 927, B-9052 Gent, Belgium Department of Medical Protein Research and Department of Biochemistry, 9000 Ghent, Belgium
| | - Estelle Giraud
- ARC Centre of Excellence in Plant Energy Biology, University of Western Australia, Australia Present address: Illumina, ANZ, 1 International Court, Scoresby Victoria 3179, Australia
| | - Frank Van Breusegem
- Department of Plant Systems Biology, VIB, and Department of Plant Biotechnology and Bioinformatics, Ghent University, Technologiepark 927, B-9052 Gent, Belgium
| | - James Whelan
- Department of Botany, ARC Centre of Excellence in Plant Energy Biology, School of Life Science, La Trobe University, Bundoora 3086, Victoria, Australia
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73
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Trono D, Laus MN, Soccio M, Pastore D. Transport pathways--proton motive force interrelationship in durum wheat mitochondria. Int J Mol Sci 2014; 15:8186-215. [PMID: 24821541 PMCID: PMC4057727 DOI: 10.3390/ijms15058186] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2014] [Revised: 04/18/2014] [Accepted: 04/24/2014] [Indexed: 12/25/2022] Open
Abstract
In durum wheat mitochondria (DWM) the ATP-inhibited plant mitochondrial potassium channel (PmitoK(ATP)) and the plant uncoupling protein (PUCP) are able to strongly reduce the proton motive force (pmf) to control mitochondrial production of reactive oxygen species; under these conditions, mitochondrial carriers lack the driving force for transport and should be inactive. However, unexpectedly, DWM uncoupling by PmitoK(ATP) neither impairs the exchange of ADP for ATP nor blocks the inward transport of Pi and succinate. This uptake may occur via the plant inner membrane anion channel (PIMAC), which is physiologically inhibited by membrane potential, but unlocks its activity in de-energized mitochondria. Probably, cooperation between PIMAC and carriers may accomplish metabolite movement across the inner membrane under both energized and de-energized conditions. PIMAC may also cooperate with PmitoK(ATP) to transport ammonium salts in DWM. Interestingly, this finding may trouble classical interpretation of in vitro mitochondrial swelling; instead of free passage of ammonia through the inner membrane and proton symport with Pi, that trigger metabolite movements via carriers, transport of ammonium via PmitoK(ATP) and that of the counteranion via PIMAC may occur. Here, we review properties, modulation and function of the above reported DWM channels and carriers to shed new light on the control that they exert on pmf and vice-versa.
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Affiliation(s)
- Daniela Trono
- Consiglio per la Ricerca e la sperimentazione in Agricoltura, Centro di Ricerca per la Cerealicoltura, S.S. 673 Km 25, 71122 Foggia, Italy.
| | - Maura N Laus
- Dipartimento di Scienze Agrarie, degli Alimenti e dell'Ambiente, Università di Foggia, Via Napoli 25, 71122 Foggia, Italy.
| | - Mario Soccio
- Dipartimento di Scienze Agrarie, degli Alimenti e dell'Ambiente, Università di Foggia, Via Napoli 25, 71122 Foggia, Italy.
| | - Donato Pastore
- Dipartimento di Scienze Agrarie, degli Alimenti e dell'Ambiente, Università di Foggia, Via Napoli 25, 71122 Foggia, Italy.
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74
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Multiparametric optical analysis of mitochondrial redox signals during neuronal physiology and pathology in vivo. Nat Med 2014; 20:555-60. [DOI: 10.1038/nm.3520] [Citation(s) in RCA: 125] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2013] [Accepted: 09/04/2013] [Indexed: 02/07/2023]
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75
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Mueller SJ, Lang D, Hoernstein SN, Lang EG, Schuessele C, Schmidt A, Fluck M, Leisibach D, Niegl C, Zimmer AD, Schlosser A, Reski R. Quantitative analysis of the mitochondrial and plastid proteomes of the moss Physcomitrella patens reveals protein macrocompartmentation and microcompartmentation. PLANT PHYSIOLOGY 2014; 164:2081-95. [PMID: 24515833 PMCID: PMC3982764 DOI: 10.1104/pp.114.235754] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/14/2014] [Accepted: 02/07/2014] [Indexed: 05/22/2023]
Abstract
Extant eukaryotes are highly compartmentalized and have integrated endosymbionts as organelles, namely mitochondria and plastids in plants. During evolution, organellar proteomes are modified by gene gain and loss, by gene subfunctionalization and neofunctionalization, and by changes in protein targeting. To date, proteomics data for plastids and mitochondria are available for only a few plant model species, and evolutionary analyses of high-throughput data are scarce. We combined quantitative proteomics, cross-species comparative analysis of metabolic pathways, and localizations by fluorescent proteins in the model plant Physcomitrella patens in order to assess evolutionary changes in mitochondrial and plastid proteomes. This study implements data-mining methodology to classify and reliably reconstruct subcellular proteomes, to map metabolic pathways, and to study the effects of postendosymbiotic evolution on organellar pathway partitioning. Our results indicate that, although plant morphologies changed substantially during plant evolution, metabolic integration of organelles is largely conserved, with exceptions in amino acid and carbon metabolism. Retargeting or regulatory subfunctionalization are common in the studied nucleus-encoded gene families of organelle-targeted proteins. Moreover, complementing the proteomic analysis, fluorescent protein fusions revealed novel proteins at organelle interfaces such as plastid stromules (stroma-filled tubules) and highlight microcompartments as well as intercellular and intracellular heterogeneity of mitochondria and plastids. Thus, we establish a comprehensive data set for mitochondrial and plastid proteomes in moss, present a novel multilevel approach to organelle biology in plants, and place our findings into an evolutionary context.
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76
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Gehl B, Lee CP, Bota P, Blatt MR, Sweetlove LJ. An Arabidopsis stomatin-like protein affects mitochondrial respiratory supercomplex organization. PLANT PHYSIOLOGY 2014; 164:1389-400. [PMID: 24424325 PMCID: PMC3938628 DOI: 10.1104/pp.113.230383] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
Stomatins belong to the band-7 protein family, a diverse group of conserved eukaryotic and prokaryotic membrane proteins involved in the formation of large protein complexes as protein-lipid scaffolds. The Arabidopsis (Arabidopsis thaliana) genome contains two paralogous genes encoding stomatin-like proteins (SLPs; AtSLP1 and AtSLP2) that are phylogenetically related to human SLP2, a protein involved in mitochondrial fusion and protein complex formation in the mitochondrial inner membrane. We used reverse genetics in combination with biochemical methods to investigate the function of AtSLPs. We demonstrate that both SLPs localize to mitochondrial membranes. SLP1 migrates as a large (approximately 3 MDa) complex in blue-native gel electrophoresis. Remarkably, slp1 knockout mutants have reduced protein and activity levels of complex I and supercomplexes, indicating that SLP affects the assembly and/or stability of these complexes. These findings point to a role for SLP1 in the organization of respiratory supercomplexes in Arabidopsis.
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77
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Welchen E, García L, Mansilla N, Gonzalez DH. Coordination of plant mitochondrial biogenesis: keeping pace with cellular requirements. FRONTIERS IN PLANT SCIENCE 2014; 4:551. [PMID: 24409193 PMCID: PMC3884152 DOI: 10.3389/fpls.2013.00551] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/15/2013] [Accepted: 12/23/2013] [Indexed: 05/20/2023]
Abstract
Plant mitochondria are complex organelles that carry out numerous metabolic processes related with the generation of energy for cellular functions and the synthesis and degradation of several compounds. Mitochondria are semiautonomous and dynamic organelles changing in shape, number, and composition depending on tissue or developmental stage. The biogenesis of functional mitochondria requires the coordination of genes present both in the nucleus and the organelle. In addition, due to their central role, all processes held inside mitochondria must be finely coordinated with those in other organelles according to cellular demands. Coordination is achieved by transcriptional control of nuclear genes encoding mitochondrial proteins by specific transcription factors that recognize conserved elements in their promoter regions. In turn, the expression of most of these transcription factors is linked to developmental and environmental cues, according to the availability of nutrients, light-dark cycles, and warning signals generated in response to stress conditions. Among the signals impacting in the expression of nuclear genes, retrograde signals that originate inside mitochondria help to adjust mitochondrial biogenesis to organelle demands. Adding more complexity, several nuclear encoded proteins are dual localized to mitochondria and either chloroplasts or the nucleus. Dual targeting might establish a crosstalk between the nucleus and cell organelles to ensure a fine coordination of cellular activities. In this article, we discuss how the different levels of coordination of mitochondrial biogenesis interconnect to optimize the function of the organelle according to both internal and external demands.
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Affiliation(s)
- Elina Welchen
- Instituto de Agrobiotecnología del Litoral–Consejo Nacional de Investigaciones Científicas y Técnicas-Universidad Nacional del LitoralSanta Fe, Argentina
- Cátedra de Biología Celular y Molecular, Facultad de Bioquímica y Ciencias Biológicas, Universidad Nacional del LitoralSanta Fe, Argentina
- *Correspondence: Elina Welchen and Daniel H. Gonzalez, Cátedra de Biología Celular y Molecular, Facultad de Bioquímica y Ciencias Biológicas, Universidad Nacional del Litoral, CC 242 Paraje El Pozo, 3000 Santa Fe, Argentina e-mail: ;
| | - Lucila García
- Instituto de Agrobiotecnología del Litoral–Consejo Nacional de Investigaciones Científicas y Técnicas-Universidad Nacional del LitoralSanta Fe, Argentina
- Cátedra de Biología Celular y Molecular, Facultad de Bioquímica y Ciencias Biológicas, Universidad Nacional del LitoralSanta Fe, Argentina
| | - Natanael Mansilla
- Instituto de Agrobiotecnología del Litoral–Consejo Nacional de Investigaciones Científicas y Técnicas-Universidad Nacional del LitoralSanta Fe, Argentina
- Cátedra de Biología Celular y Molecular, Facultad de Bioquímica y Ciencias Biológicas, Universidad Nacional del LitoralSanta Fe, Argentina
| | - Daniel H. Gonzalez
- Instituto de Agrobiotecnología del Litoral–Consejo Nacional de Investigaciones Científicas y Técnicas-Universidad Nacional del LitoralSanta Fe, Argentina
- Cátedra de Biología Celular y Molecular, Facultad de Bioquímica y Ciencias Biológicas, Universidad Nacional del LitoralSanta Fe, Argentina
- *Correspondence: Elina Welchen and Daniel H. Gonzalez, Cátedra de Biología Celular y Molecular, Facultad de Bioquímica y Ciencias Biológicas, Universidad Nacional del Litoral, CC 242 Paraje El Pozo, 3000 Santa Fe, Argentina e-mail: ;
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78
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Finsterer J, Ohnsorge P. Influence of mitochondrion-toxic agents on the cardiovascular system. Regul Toxicol Pharmacol 2013; 67:434-45. [DOI: 10.1016/j.yrtph.2013.09.002] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2013] [Revised: 09/01/2013] [Accepted: 09/02/2013] [Indexed: 10/26/2022]
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79
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Zhao Y, Pan Z, Zhang Y, Qu X, Zhang Y, Yang Y, Jiang X, Huang S, Yuan M, Schumaker KS, Guo Y. The actin-related Protein2/3 complex regulates mitochondrial-associated calcium signaling during salt stress in Arabidopsis. THE PLANT CELL 2013; 25:4544-59. [PMID: 24280386 PMCID: PMC3875735 DOI: 10.1105/tpc.113.117887] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/26/2013] [Revised: 10/30/2013] [Accepted: 11/14/2013] [Indexed: 05/18/2023]
Abstract
Microfilament and Ca(2+) dynamics play important roles in stress signaling in plants. Through genetic screening of Arabidopsis thaliana mutants that are defective in stress-induced increases in cytosolic Ca(2+) ([Ca(2+)]cyt), we identified Actin-Related Protein2 (Arp2) as a regulator of [Ca(2+)]cyt in response to salt stress. Plants lacking Arp2 or other proteins in the Arp2/3 complex exhibited enhanced salt-induced increases in [Ca(2+)]cyt, decreased mitochondria movement, and hypersensitivity to salt. In addition, mitochondria aggregated, the mitochondrial permeability transition pore opened, and mitochondrial membrane potential Ψm was impaired in the arp2 mutant, and these changes were associated with salt-induced cell death. When opening of the enhanced mitochondrial permeability transition pore was blocked or increases in [Ca(2+)]cyt were prevented, the salt-sensitive phenotype of the arp2 mutant was partially rescued. These results indicate that the Arp2/3 complex regulates mitochondrial-dependent Ca(2+) signaling in response to salt stress.
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Affiliation(s)
- Yi Zhao
- State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, Beijing 100193, China
| | - Zhen Pan
- State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, Beijing 100193, China
- College of Life Sciences and Biotechnology, Beijing Forestry University, Beijing 100083, China
| | - Yan Zhang
- State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, Beijing 100193, China
| | - Xiaolu Qu
- Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
| | - Yuguo Zhang
- State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, Beijing 100193, China
| | - Yongqing Yang
- State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, Beijing 100193, China
| | - Xiangning Jiang
- College of Life Sciences and Biotechnology, Beijing Forestry University, Beijing 100083, China
- National Engineering Laboratory of Tree Breeding, The Tree and Ornamental Plant Breeding and Biotechnology Laboratory of State Forestry Administration, Beijing 100083, China
| | - Shanjin Huang
- Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
| | - Ming Yuan
- State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, Beijing 100193, China
| | | | - Yan Guo
- State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, Beijing 100193, China
- National Center for Plant Gene Research, Beijing 100193, China
- Address correspondence to
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80
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Cheung CYM, Williams TCR, Poolman MG, Fell DA, Ratcliffe RG, Sweetlove LJ. A method for accounting for maintenance costs in flux balance analysis improves the prediction of plant cell metabolic phenotypes under stress conditions. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2013; 75:1050-61. [PMID: 23738527 DOI: 10.1111/tpj.12252] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/03/2013] [Revised: 05/23/2013] [Accepted: 05/30/2013] [Indexed: 05/24/2023]
Abstract
Flux balance models of metabolism generally utilize synthesis of biomass as the main determinant of intracellular fluxes. However, the biomass constraint alone is not sufficient to predict realistic fluxes in central heterotrophic metabolism of plant cells because of the major demand on the energy budget due to transport costs and cell maintenance. This major limitation can be addressed by incorporating transport steps into the metabolic model and by implementing a procedure that uses Pareto optimality analysis to explore the trade-off between ATP and NADPH production for maintenance. This leads to a method for predicting cell maintenance costs on the basis of the measured flux ratio between the oxidative steps of the oxidative pentose phosphate pathway and glycolysis. We show that accounting for transport and maintenance costs substantially improves the accuracy of fluxes predicted from a flux balance model of heterotrophic Arabidopsis cells in culture, irrespective of the objective function used in the analysis. Moreover, when the new method was applied to cells under control, elevated temperature and hyper-osmotic conditions, only elevated temperature led to a substantial increase in cell maintenance costs. It is concluded that the hyper-osmotic conditions tested did not impose a metabolic stress, in as much as the metabolic network is not forced to devote more resources to cell maintenance.
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Affiliation(s)
- C Y Maurice Cheung
- Department of Plant Sciences, University of Oxford, South Parks Road, Oxford, OX1 3RB, UK
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81
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Optical microwell array for large scale studies of single mitochondria metabolic responses. Anal Bioanal Chem 2013; 406:931-41. [PMID: 23892878 DOI: 10.1007/s00216-013-7211-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2013] [Revised: 06/27/2013] [Accepted: 07/02/2013] [Indexed: 12/21/2022]
Abstract
Microsystems based on microwell arrays have been widely used for studies on single living cells. In this work, we focused on the subcellular level in order to monitor biological responses directly on individual organelles. Consequently, we developed microwell arrays for the entrapment and fluorescence microscopy of single isolated organelles, mitochondria herein. Highly dense arrays of 3-μm mean diameter wells were obtained by wet chemical etching of optical fiber bundles. Favorable conditions for the stable entrapment of individual mitochondria within a majority of microwells were found. Owing to NADH auto-fluorescence, the metabolic status of each mitochondrion was analyzed at resting state (Stage 1), then following the addition of a respiratory substrate (Stage 2), ethanol herein, and of a respiratory inhibitor (Stage 3), antimycin A. Mean levels of mitochondrial NADH were increased by 29% and 35% under Stages 2 and 3, respectively. We showed that mitochondrial ability to generate higher levels of NADH (i.e., its metabolic performance) is not correlated either to the initial energetic state or to the respective size of each mitochondrion. This study demonstrates that microwell arrays allow metabolic studies on populations of isolated mitochondria with a single organelle resolution.
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82
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Malhotra K, Sathappa M, Landin JS, Johnson AE, Alder NN. Structural changes in the mitochondrial Tim23 channel are coupled to the proton-motive force. Nat Struct Mol Biol 2013; 20:965-72. [DOI: 10.1038/nsmb.2613] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2012] [Accepted: 05/14/2013] [Indexed: 01/11/2023]
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83
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Superoxide constitutes a major signal of mitochondrial superoxide flash. Life Sci 2013; 93:178-86. [PMID: 23800644 DOI: 10.1016/j.lfs.2013.06.012] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2013] [Revised: 06/08/2013] [Accepted: 06/12/2013] [Indexed: 11/21/2022]
Abstract
AIMS Mitochondrial flashes detected with an N- and C-terminal circularly-permuted yellow fluorescent protein (cpYFP) have been thought to represent transient and quantal bursts of superoxide production under physiological, stressful and pathophysiological conditions. However, the superoxide nature of the cpYFP-flash has been challenged, considering the pH-sensitivity of cpYFP and the distinctive regulation of the flash versus the basal production of mitochondrial reactive oxygen species (ROS). Thus, the aim of the study is to further determine the origin of mitochondrial flashes. MAIN METHODS We investigated the origin of the flashes using the widely-used pH-insensitive ROS indicators, mitoSOX, an indicator for superoxide, and 2, 7-dichlorodihydrofluorescein diacetate (DCF), an indicator for H2O2 and other oxidants. KEY FINDINGS Robust, quantal, and stochastic mitochondrial flashes were detected with either mitoSOX or DCF in several cell-types and in mitochondria isolated from the heart. Both mitoSOX-flashes and DCF-flashes showed similar incidence and kinetics to those of cpYFP-flashes, and were equally sensitive to mitochondria-targeted antioxidants. Furthermore, they were markedly decreased by inhibitors or an uncoupler of the mitochondrial electron transport chain, as is the case with cpYFP-flashes. The involvement of the mitochondrial permeability transition pore in DCF-flashes was evidenced by the coincidental loss of mitochondrial membrane potential and matrix-enriched rhod-2, as well as by their sensitivity to cyclosporine A. SIGNIFICANCE These data indicate that all the three types of mitochondrial flashes stem from the common physiological process of bursting superoxide and ensuing H2O2 production in the matrix of single mitochondrion.
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84
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Abstract
SIGNIFICANCE For a plant to grow and develop, energy and appropriate building blocks are a fundamental requirement. Mitochondrial respiration is a vital source for both. The delicate redox processes that make up respiration are affected by the plant's changing environment. Therefore, mitochondrial regulation is critically important to maintain cellular homeostasis. This involves sensing signals from changes in mitochondrial physiology, transducing this information, and mounting tailored responses, by either adjusting mitochondrial and cellular functions directly or reprogramming gene expression. RECENT ADVANCES Retrograde (RTG) signaling, by which mitochondrial signals control nuclear gene expression, has been a field of very active research in recent years. Nevertheless, no mitochondrial RTG-signaling pathway is yet understood in plants. This review summarizes recent advances toward elucidating redox processes and other bioenergetic factors as a part of RTG signaling of plant mitochondria. CRITICAL ISSUES Novel insights into mitochondrial physiology and redox-regulation provide a framework of upstream signaling. On the other end, downstream responses to modified mitochondrial function have become available, including transcriptomic data and mitochondrial phenotypes, revealing processes in the plant that are under mitochondrial control. FUTURE DIRECTIONS Drawing parallels to chloroplast signaling and mitochondrial signaling in animal systems allows to bridge gaps in the current understanding and to deduce promising directions for future research. It is proposed that targeted usage of new technical approaches, such as quantitative in vivo imaging, will provide novel leverage to the dissection of plant mitochondrial signaling.
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85
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OPA1 promotes pH flashes that spread between contiguous mitochondria without matrix protein exchange. EMBO J 2013; 32:1927-40. [PMID: 23714779 PMCID: PMC3981180 DOI: 10.1038/emboj.2013.124] [Citation(s) in RCA: 82] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2012] [Accepted: 04/19/2013] [Indexed: 01/13/2023] Open
Abstract
The chemical nature and functional significance of mitochondrial flashes associated with fluctuations in mitochondrial membrane potential is unclear. Using a ratiometric pH probe insensitive to superoxide, we show that flashes reflect matrix alkalinization transients of ∼0.4 pH units that persist in cells permeabilized in ion-free solutions and can be evoked by imposed mitochondrial depolarization. Ablation of the pro-fusion protein Optic atrophy 1 specifically abrogated pH flashes and reduced the propagation of matrix photoactivated GFP (paGFP). Ablation or invalidation of the pro-fission Dynamin-related protein 1 greatly enhanced flash propagation between contiguous mitochondria but marginally increased paGFP matrix diffusion, indicating that flashes propagate without matrix content exchange. The pH flashes were associated with synchronous depolarization and hyperpolarization events that promoted the membrane potential equilibration of juxtaposed mitochondria. We propose that flashes are energy conservation events triggered by the opening of a fusion pore between two contiguous mitochondria of different membrane potentials, propagating without matrix fusion to equilibrate the energetic state of connected mitochondria. Mitochondrial fusion events and transient changes in matrix pH linked to membrane depolarization are found to underlie mitochondrial flashes, whose propagation may help equilibrate energy states between connected mitochondria.
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86
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Suraniti E, Vajrala VS, Goudeau B, Bottari SP, Rigoulet M, Devin A, Sojic N, Arbault S. Monitoring metabolic responses of single mitochondria within poly(dimethylsiloxane) wells: study of their endogenous reduced nicotinamide adenine dinucleotide evolution. Anal Chem 2013; 85:5146-52. [PMID: 23600852 DOI: 10.1021/ac400494e] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
It is now demonstrated that mitochondria individually function differently because of specific energetic needs in cell compartments but also because of the genetic heterogeneity within the mitochondrial pool-network of a cell. Consequently, understanding mitochondrial functioning at the single organelle level is of high interest for biomedical research, therefore being a target for analyticians. In this context, we developed easy-to-build platforms of milli- to microwells for fluorescence microscopy of single isolated mitochondria. Poly(dimethylsiloxane) (PDMS) was determined to be an excellent material for mitochondrial deposition and observation of their NADH content. Because of NADH autofluorescence, the metabolic status of each mitochondrion was analyzed following addition of a respiratory substrate (stage 2), ethanol herein, and a respiratory inhibitor (stage 3), Antimycin A. Mean levels of mitochondrial NADH were increased by 32% and 62% under stages 2 and 3, respectively. Statistical studies of NADH value distributions evidenced different types of responses, at least three, to ethanol and Antimycin A within the mitochondrial population. In addition, we showed that mitochondrial ability to generate high levels of NADH, that is its metabolic performance, is not correlated either to the initial energetic state or to the respective size of each mitochondrion.
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87
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Wei-LaPierre L, Gong G, Gerstner BJ, Ducreux S, Yule DI, Pouvreau S, Wang X, Sheu SS, Cheng H, Dirksen RT, Wang W. Respective contribution of mitochondrial superoxide and pH to mitochondria-targeted circularly permuted yellow fluorescent protein (mt-cpYFP) flash activity. J Biol Chem 2013; 288:10567-77. [PMID: 23457298 DOI: 10.1074/jbc.m113.455709] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Superoxide flashes are transient bursts of superoxide production within the mitochondrial matrix that are detected using the superoxide-sensitive biosensor, mitochondria-targeted circularly permuted YFP (mt-cpYFP). However, due to the pH sensitivity of mt-cpYFP, flashes were suggested to reflect transient events of mitochondrial alkalinization. Here, we simultaneously monitored flashes with mt-cpYFP and mitochondrial pH with carboxy-SNARF-1. In intact cardiac myocytes and purified skeletal muscle mitochondria, robust mt-cpYFP flashes were accompanied by only a modest increase in SNARF-1 ratio (corresponding to a pH increase of <0.1), indicating that matrix alkalinization is minimal during an mt-cpYFP flash. Individual flashes were also accompanied by stepwise increases of MitoSOX signal and decreases of NADH autofluorescence, supporting the superoxide origin of mt-cpYFP flashes. Transient matrix alkalinization induced by NH4Cl only minimally influenced flash frequency and failed to alter flash amplitude. However, matrix acidification modulated superoxide flash frequency in a bimodal manner. Low concentrations of nigericin (< 100 nM) that resulted in a mild dissipation of the mitochondrial pH gradient increased flash frequency, whereas a maximal concentration of nigericin (5 μm) collapsed the pH gradient and abolished flash activity. These results indicate that mt-cpYFP flash events reflect a burst in electron transport chain-dependent superoxide production that is coincident with a modest increase in matrix pH. Furthermore, flash activity depends strongly on a combination of mitochondrial oxidation and pH gradient.
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Affiliation(s)
- Lan Wei-LaPierre
- Department of Pharmacology and Physiology, University of Rochester Medical Center, Rochester, New York 14642, USA
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88
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Vellosillo T, Aguilera V, Marcos R, Bartsch M, Vicente J, Cascón T, Hamberg M, Castresana C. Defense activated by 9-lipoxygenase-derived oxylipins requires specific mitochondrial proteins. PLANT PHYSIOLOGY 2013; 161:617-27. [PMID: 23370715 PMCID: PMC3561008 DOI: 10.1104/pp.112.207514] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
9-Lipoxygenases (9-LOXs) initiate fatty acid oxygenation, resulting in the formation of oxylipins activating plant defense against hemibiotrophic pathogenic bacteria. Previous studies using nonresponding to oxylipins (noxy), a series of Arabidopsis (Arabidopsis thaliana) mutants insensitive to the 9-LOX product 9-hydroxy-10,12,15-octadecatrienoic acid (9-HOT), have demonstrated the importance of cell wall modifications as a component of 9-LOX-induced defense. Here, we show that a majority (71%) of 41 studied noxy mutants have an added insensitivity to isoxaben, an herbicide inhibiting cellulose synthesis and altering the cell wall. The specific mutants noxy2, noxy15, and noxy38, insensitive to both 9-HOT and isoxaben, displayed enhanced susceptibility to Pseudomonas syringae DC3000 as well as reduced activation of salicylic acid-responding genes. Map-based cloning identified the mutation in noxy2 as At5g11630 encoding an uncharacterized mitochondrial protein, designated NOXY2. Moreover, noxy15 and noxy38 were mapped at the DYNAMIN RELATED PROTEIN3A and FRIENDLY MITOCHONDRIA loci, respectively. Fluorescence microscopy and molecular analyses revealed that the three noxy mutants characterized exhibit mitochondrial dysfunction and that 9-HOT added to wild-type Arabidopsis causes mitochondrial aggregation and loss of mitochondrial membrane potential. The results suggest that the defensive responses and cell wall modifications caused by 9-HOT are under mitochondrial retrograde control and that mitochondria play a fundamental role in innate immunity signaling.
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Affiliation(s)
- Tamara Vellosillo
- Centro Nacional de Biotecnología-Consejo Superior de Investigaciones Científicas, Campus Universidad Autónoma, Cantoblanco, E-28049 Madrid, Spain
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89
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Trono D, Soccio M, Laus MN, Pastore D. The existence of phospholipase A(2) activity in plant mitochondria and its activation by hyperosmotic stress in durum wheat (Triticum durum Desf.). PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2013; 199-200:91-102. [PMID: 23265322 DOI: 10.1016/j.plantsci.2012.11.002] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/02/2012] [Revised: 11/09/2012] [Accepted: 11/10/2012] [Indexed: 05/19/2023]
Abstract
The activity of mitochondrial phospholipase A(2) (PLA(2)) was shown for the first time in plants. It was observed in etiolated seedlings from durum wheat, barley, tomato, spelt and green seedlings of maize, but not in potato and topinambur tubers and lentil etiolated seedlings. This result was achieved by a novel spectrophotometric assay based on the coupled PLA(2)/lipoxygenase reactions using 1-palmitoyl-2-linoleoyl-sn-glycero-3-phosphatidylcholine as substrate; the mitochondrial localisation was assessed by checking recovery of marker enzymes. Durum wheat mitochondrial PLA(2) (DWM-PLA(2)) showed maximal activity at pH 9.0 and 1mM Ca(2+), hyperbolic kinetics (K(m)=90±6μM, V(max)=29±1nmolmin(-1)mg(-1) of protein) and inhibition by methyl arachidonyl fluorophosphonate, 5-(4-benzyloxyphenyl)-4S-(7-phenylheptanoylamino)pentanoic acid and palmityl trifluoromethyl ketone. Reactive oxygen species had no effect on DWM-PLA(2), that instead was activated by about 50% and 95%, respectively, under salt (0.21M NaCl) and osmotic (0.42M mannitol) stress imposed during germination. Contrarily, a secondary Ca(2+)-independent activity, having optimum at pH 7.0, was stress-insensitive. We propose that the activation of DWM-PLA(2) is responsible for the strong increase of free fatty acids recently measured in mitochondria under the same stress conditions [Laus, et al., J. Exp. Bot. 62 (2011) 141-154] that, in turn, activate potassium channel and uncoupling protein, able to counteract hyperosmotic stress.
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Affiliation(s)
- Daniela Trono
- Consiglio per la Ricerca e la sperimentazione in Agricoltura - Centro di Ricerca per la Cerealicoltura, Foggia, Italy
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90
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Loro G, Ruberti C, Zottini M, Costa A. The D3cpv Cameleon reports Ca²⁺ dynamics in plant mitochondria with similar kinetics of the YC3.6 Cameleon, but with a lower sensitivity. J Microsc 2012; 249:8-12. [PMID: 23227874 DOI: 10.1111/j.1365-2818.2012.03683.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Mitochondria are key organelles involved in many aspects of plant physiology and, their ability to generate specific Ca²⁺ signatures in response to abiotic and biotic stimuli has been reported as one of their roles. The recent identification of the mammalian mitochondrial Ca²⁺ uniporter opens a new research area in plant biology. To study the mitochondrial Ca²⁺ handling, it is essential to have a reliable probe. Here we have reported the generation of an Arabidopsis transgenic line expressing the genetically encoded probe Cameleon D3cpv targeted to mitochondria, and compared its properties with the already known Cameleon YC3.6.
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Affiliation(s)
- G Loro
- Dipartimento di Biologia, Università degli Studi di Padova, Via U. Bassi, Padova, Italia
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91
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Affiliation(s)
- Emilie Quatresous
- Centre National de la Recherche Scientifique (CNRS) UMR 5534, Centre de Génétique et de Physiologie Moléculaire et Cellulaire, Université Lyon 1, 69622 Villeurbanne, France
| | - Claude Legrand
- Centre National de la Recherche Scientifique (CNRS) UMR 5534, Centre de Génétique et de Physiologie Moléculaire et Cellulaire, Université Lyon 1, 69622 Villeurbanne, France
| | - Sandrine Pouvreau
- CNRS UMR 5297, Interdisciplinary Institute for Neuroscience, University of Bordeaux, F-33000 Bordeaux, France
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92
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Mitochondrial ‘flashes’: a radical concept repHined. Trends Cell Biol 2012; 22:503-8. [DOI: 10.1016/j.tcb.2012.07.007] [Citation(s) in RCA: 74] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2012] [Revised: 07/18/2012] [Accepted: 07/19/2012] [Indexed: 11/23/2022]
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93
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Murayama M, Hayashi S, Nishimura N, Ishide M, Kobayashi K, Yagi Y, Asami T, Nakamura T, Shinozaki K, Hirayama T. Isolation of Arabidopsis ahg11, a weak ABA hypersensitive mutant defective in nad4 RNA editing. JOURNAL OF EXPERIMENTAL BOTANY 2012; 63:5301-10. [PMID: 22821940 PMCID: PMC3430999 DOI: 10.1093/jxb/ers188] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
The phytohormone abscisic acid (ABA) plays pivotal roles in the regulation of developmental and environmental responses in plants. Identification of cytoplasmic ABA receptors enabled the elucidation of the main ABA signalling pathway, connecting ABA perception to either nuclear events or the action of several transporters. However, the physiological functions of ABA in cellular processes largely remain unknown. To obtain greater insight into the ABA response, genetic screening was performed to isolate ABA-related mutants of Arabidopsis and several novel ABA-hypersensitive mutants were isolated. One of those mutants--ahg11--was characterized further. Map-based cloning showed that AHG11 encodes a PPR type protein, which has potential roles in RNA editing. An AHG11-GFP fusion protein indicated that AHG11 mainly localized to the mitochondria. Consistent with this observation, the nad4 transcript, which normally undergoes RNA editing, lacks a single RNA editing event conferring a conversion of an amino acid residue in ahg11 mutants. The geminating ahg11 seeds have higher levels of reactive-oxygen-species-responsive genes. Presumably, partial impairment of mitochondrial function caused by an amino acid conversion in one of the complex I components induces redox imbalance which, in turn, confers an abnormal response to the plant hormone.
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Affiliation(s)
- Maki Murayama
- Graduate School of Nanobioscience, Yokohama City University, 1-7-29 Suehiro, Tsurumi, Yokohama 230-0045, Japan
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94
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COLAÇO R, MORENO N, FEIJÓ J. On the fast lane: mitochondria structure, dynamics and function in growing pollen tubes. J Microsc 2012; 247:106-18. [DOI: 10.1111/j.1365-2818.2012.03628.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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95
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Vestergaard CL, Flyvbjerg H, Møller IM. Intracellular signaling by diffusion: can waves of hydrogen peroxide transmit intracellular information in plant cells? FRONTIERS IN PLANT SCIENCE 2012; 3:295. [PMID: 23293647 PMCID: PMC3533182 DOI: 10.3389/fpls.2012.00295] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/18/2012] [Accepted: 12/10/2012] [Indexed: 05/21/2023]
Abstract
Amplitude- and frequency-modulated waves of Ca(2+) ions transmit information inside cells. Reactive Oxygen Species (ROS), specifically hydrogen peroxide, have been proposed to have a similar role in plant cells. We consider the feasibility of such an intracellular communication system in view of the physical and biochemical conditions in plant cells. As model system, we use a H(2)O(2) signal originating at the plasma membrane (PM) and spreading through the cytosol. We consider two maximally simple types of signals, isolated pulses and harmonic oscillations. First we consider the basic limits on such signals as regards signal origin, frequency, amplitude, and distance. Then we establish the impact of ROS-removing enzymes on the ability of H(2)O(2) to transmit signals. Finally, we consider to what extent cytoplasmic streaming distorts signals. This modeling allows us to predict the conditions under which diffusion-mediated signaling is possible. We show that purely diffusive transmission of intracellular information by H(2)O(2) over a distance of 1 μm (typical distance between organelles, which may function as relay stations) is possible at frequencies well above 1 Hz, which is the highest frequency observed experimentally. This allows both frequency and amplitude modulation of the signal. Signaling over a distance of 10 μm (typical distance between the PM and the nucleus) may be possible, but requires high signal amplitudes or, equivalently, a very low detection threshold. Furthermore, at this longer distance a high rate of enzymatic degradation is required to make signaling at frequencies above 0.1 Hz possible. In either case, cytoplasmic streaming does not seriously disturb signals. We conclude that although purely diffusion-mediated signaling without relaying stations is theoretically possible, it is unlikely to work in practice, since it requires a much faster enzymatic degradation and a much lower cellular background concentration of H(2)O(2) than observed experimentally.
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Affiliation(s)
| | - Henrik Flyvbjerg
- Department of Micro- and Nanotechnology, Technical University of DenmarkKongens Lyngby, Denmark
| | - Ian Max Møller
- Department of Molecular Biology and Genetics, Science and Technology, Aarhus UniversitySlagelse, Denmark
- *Correspondence: Ian Max Møller, Department of Molecular Biology and Genetics, Science and Technology, Aarhus University, Forsøgsvej 1, DK-4200 Slagelse, Denmark. e-mail:
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