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Zhang H, Rundle C, Winter N, Miricescu A, Mooney BC, Bachmair A, Graciet E, Theodoulou FL. BIG enhances Arg/N-degron pathway-mediated protein degradation to regulate Arabidopsis hypoxia responses and suberin deposition. Plant Cell 2024:koae117. [PMID: 38608155 DOI: 10.1093/plcell/koae117] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/22/2023] [Revised: 03/15/2024] [Accepted: 03/21/2024] [Indexed: 04/14/2024]
Abstract
BIG/DARK OVEREXPRESSION OF CAB1/TRANSPORT INHIBITOR RESPONSE3 is a 0.5-MDa protein associated with multiple functions in Arabidopsis (Arabidopsis thaliana) signalling and development. However, the biochemical functions of BIG are unknown. We investigated a role for BIG in the Arg/N-degron pathways, in which substrate protein fate is influenced by the N-terminal (Nt) residue. We crossed a big loss-of-function allele to two N-degron pathway E3 ligase mutants, proteolysis6 (prt6) and prt1, and examined the stability of protein substrates. Stability of model substrates was enhanced in prt6-1 big-2 and prt1-1 big-2 relative to the respective single mutants and the abundance of the PRT6 physiological substrates, HYPOXIA-RESPONSIVE ERF2 (HRE2) and VERNALIZATION2 (VRN2) was similarly increased in prt6 big double mutants. Hypoxia marker expression was enhanced in prt6 big double mutants; this constitutive response required arginyltransferase activity and RAP-type ERFVII transcription factors. Transcriptomic analysis of roots not only demonstrated increased expression of multiple hypoxia-responsive genes in the double mutant relative to prt6, but also revealed other roles for PRT6 and BIG, including regulation of suberin deposition through both ERFVII-dependent and independent mechanisms, respectively. Our results show that BIG acts together with PRT6 to regulate the hypoxia response and broader processes in Arabidopsis.
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Affiliation(s)
- Hongtao Zhang
- Plant Sciences and the Bioeconomy, Rothamsted Research, Harpenden, AL5 2JQ, UK
| | - Chelsea Rundle
- Plant Sciences and the Bioeconomy, Rothamsted Research, Harpenden, AL5 2JQ, UK
| | - Nikola Winter
- Department of Biochemistry and Cell Biology, Max Perutz Labs, University of Vienna, Vienna, Austria
| | | | - Brian C Mooney
- Department of Biology, Maynooth University, Maynooth, Ireland
| | - Andreas Bachmair
- Department of Biochemistry and Cell Biology, Max Perutz Labs, University of Vienna, Vienna, Austria
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2
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Zhang H, Linster E, Wirtz M, Theodoulou FL. Relative Protein Lifetime Measurement in Plants Using Tandem Fluorescent Protein Timers. Methods Mol Biol 2023; 2581:201-220. [PMID: 36413319 DOI: 10.1007/978-1-0716-2784-6_14] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Targeted protein degradation plays a wide range of important roles in plant growth and development, but analyzing protein turnover in vivo is technically challenging. Until recently, there has been no straightforward methodology for quantifying protein dynamics at subcellular resolution during cellular transitions in plants. A tandem fluorescent protein timer (tFT) is a fusion of two different fluorescent proteins with distinct fluorophore maturation kinetics, which allows estimation of relative protein age from the ratio of fluorescence intensities of the two fluorescent proteins. Here, we describe approaches to use this technology to report relative protein lifetime in both transient and stable plant transformation systems. tFTs enable in vivo, real-time protein lifetime assessment within subcellular compartments and across tissues, permitting the analysis of protein degradation dynamics in response to stresses or developmental cues and in different genetic backgrounds.
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Affiliation(s)
- Hongtao Zhang
- Plant Sciences and the Bioeconomy, Rothamsted Research, Harpenden, UK
| | - Eric Linster
- Centre for Organismal Studies, University of Heidelberg, Heidelberg, Germany
| | - Markus Wirtz
- Centre for Organismal Studies, University of Heidelberg, Heidelberg, Germany
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3
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Liu Z, Hartman S, van Veen H, Zhang H, Leeggangers HACF, Martopawiro S, Bosman F, de Deugd F, Su P, Hummel M, Rankenberg T, Hassall KL, Bailey-Serres J, Theodoulou FL, Voesenek LACJ, Sasidharan R. Ethylene augments root hypoxia tolerance via growth cessation and reactive oxygen species amelioration. Plant Physiol 2022; 190:1365-1383. [PMID: 35640551 PMCID: PMC9516759 DOI: 10.1093/plphys/kiac245] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/27/2022] [Accepted: 04/29/2022] [Indexed: 05/20/2023]
Abstract
Flooded plants experience impaired gas diffusion underwater, leading to oxygen deprivation (hypoxia). The volatile plant hormone ethylene is rapidly trapped in submerged plant cells and is instrumental for enhanced hypoxia acclimation. However, the precise mechanisms underpinning ethylene-enhanced hypoxia survival remain unclear. We studied the effect of ethylene pretreatment on hypoxia survival of Arabidopsis (Arabidopsis thaliana) primary root tips. Both hypoxia itself and re-oxygenation following hypoxia are highly damaging to root tip cells, and ethylene pretreatments reduced this damage. Ethylene pretreatment alone altered the abundance of transcripts and proteins involved in hypoxia responses, root growth, translation, and reactive oxygen species (ROS) homeostasis. Through imaging and manipulating ROS abundance in planta, we demonstrated that ethylene limited excessive ROS formation during hypoxia and subsequent re-oxygenation and improved oxidative stress survival in a PHYTOGLOBIN1-dependent manner. In addition, we showed that root growth cessation via ethylene and auxin occurred rapidly and that this quiescence behavior contributed to enhanced hypoxia tolerance. Collectively, our results show that the early flooding signal ethylene modulates a variety of processes that all contribute to hypoxia survival.
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Affiliation(s)
| | | | | | - Hongtao Zhang
- Plant Sciences and the Bioeconomy, Rothamsted Research, Harpenden AL5 2JQ, UK
| | - Hendrika A C F Leeggangers
- Plant-Environment Signaling, Institute of Environmental Biology, Utrecht University, Utrecht, 3584 CH, The Netherlands
| | - Shanice Martopawiro
- Plant-Environment Signaling, Institute of Environmental Biology, Utrecht University, Utrecht, 3584 CH, The Netherlands
| | - Femke Bosman
- Plant-Environment Signaling, Institute of Environmental Biology, Utrecht University, Utrecht, 3584 CH, The Netherlands
| | - Florian de Deugd
- Plant-Environment Signaling, Institute of Environmental Biology, Utrecht University, Utrecht, 3584 CH, The Netherlands
| | - Peng Su
- Plant-Environment Signaling, Institute of Environmental Biology, Utrecht University, Utrecht, 3584 CH, The Netherlands
| | - Maureen Hummel
- Department of Botany and Plant Sciences, Center for Plant Cell Biology, University of California, Riverside, California 92521, USA
| | - Tom Rankenberg
- Plant-Environment Signaling, Institute of Environmental Biology, Utrecht University, Utrecht, 3584 CH, The Netherlands
| | - Kirsty L Hassall
- Intelligent Data Ecosystems, Rothamsted Research, Harpenden AL5 2JQ, UK
| | - Julia Bailey-Serres
- Plant-Environment Signaling, Institute of Environmental Biology, Utrecht University, Utrecht, 3584 CH, The Netherlands
- Department of Botany and Plant Sciences, Center for Plant Cell Biology, University of California, Riverside, California 92521, USA
| | | | - Laurentius A C J Voesenek
- Plant-Environment Signaling, Institute of Environmental Biology, Utrecht University, Utrecht, 3584 CH, The Netherlands
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4
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Till CJ, Vicente J, Zhang H, Oszvald M, Deery MJ, Pastor V, Lilley KS, Ray RV, Theodoulou FL, Holdsworth MJ. The Arabidopsis thaliana N-recognin E3 ligase PROTEOLYSIS1 influences the immune response. Plant Direct 2019; 3:e00194. [PMID: 31891113 PMCID: PMC6933115 DOI: 10.1002/pld3.194] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/22/2019] [Revised: 11/22/2019] [Accepted: 12/02/2019] [Indexed: 05/11/2023]
Abstract
N-degron pathways of ubiquitin-mediated proteolysis (formerly known as the N-end rule pathway) control the stability of substrate proteins dependent on the amino-terminal (Nt) residue. Unlike yeast or mammalian N-recognin E3 ligases, which each recognize several different classes of Nt residues, in Arabidopsis thaliana, N-recognin functions of different N-degron pathways are carried out independently by PROTEOLYSIS (PRT)1, PRT6, and other unknown proteins. PRT1 recognizes type 2 aromatic Nt-destabilizing residues and PRT6 recognizes type 1 basic residues. These two N-recognin functions diverged as separate proteins early in the evolution of plants, before the conquest of the land. We demonstrate that loss of PRT1 function promotes the plant immune system, as mutant prt1-1 plants showed greater apoplastic resistance than WT to infection by the bacterial hemi-biotroph Pseudomonas syringae pv tomato (Pst) DC3000. Quantitative proteomics revealed increased accumulation of proteins associated with specific components of plant defense in the prt1-1 mutant, concomitant with increased accumulation of salicylic acid. The effects of the prt1 mutation were additional to known effects of prt6 in influencing the immune system, in particular, an observed over-accumulation of pipecolic acid (Pip) in the double-mutant prt1-1 prt6-1. These results demonstrate a potential role for PRT1 in controlling aspects of the plant immune system and suggest that PRT1 limits the onset of the defense response via degradation of substrates with type 2 Nt-destabilizing residues.
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Affiliation(s)
- Christopher J. Till
- School of BiosciencesUniversity of NottinghamLoughboroughUK
- Plant Sciences DepartmentRothamsted ResearchHarpendenUK
| | - Jorge Vicente
- School of BiosciencesUniversity of NottinghamLoughboroughUK
| | - Hongtao Zhang
- Plant Sciences DepartmentRothamsted ResearchHarpendenUK
- Cambridge Centre for ProteomicsDepartment of BiochemistryUniversity of CambridgeCambridgeUK
| | - Maria Oszvald
- Plant Sciences DepartmentRothamsted ResearchHarpendenUK
| | - Michael J. Deery
- Cambridge Centre for ProteomicsDepartment of BiochemistryUniversity of CambridgeCambridgeUK
| | - Victoria Pastor
- Área de Fisiología VegetalDepartamento de Ciencias Agrarias y del Medio NaturalUniversitat Jaume ICastellónSpain
| | - Kathryn S. Lilley
- Cambridge Centre for ProteomicsDepartment of BiochemistryUniversity of CambridgeCambridgeUK
| | - Rumiana V. Ray
- School of BiosciencesUniversity of NottinghamLoughboroughUK
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5
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Zhang H, Linster E, Gannon L, Leemhuis W, Rundle CA, Theodoulou FL, Wirtz M. Tandem Fluorescent Protein Timers for Noninvasive Relative Protein Lifetime Measurement in Plants. Plant Physiol 2019; 180:718-731. [PMID: 30872425 PMCID: PMC6548237 DOI: 10.1104/pp.19.00051] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/15/2019] [Accepted: 03/08/2019] [Indexed: 05/17/2023]
Abstract
Targeted protein degradation is an important and pervasive regulatory mechanism in plants, required for perception and response to the environment as well as developmental signaling. Despite the significance of this process, relatively few studies have assessed plant protein turnover in a quantitative fashion. Tandem fluorescent protein timers (tFTs) offer a powerful approach for the assessment of in vivo protein turnover in distinct subcellular compartments of single or multiple cells. A tFT is a fusion of two different fluorescent proteins with distinct fluorophore maturation kinetics, which enable protein age to be estimated from the ratio of fluorescence intensities of the two fluorescent proteins. Here, we used short-lived auxin signaling proteins and model N-end rule (N-recognin) pathway reporters to demonstrate the utility of tFTs for studying protein turnover in living plant cells of Arabidopsis (Arabidopsis thaliana) and Nicotiana benthamiana We present transient expression of tFTs as an efficient screen for relative protein lifetime, useful for testing the effects of mutations and different genetic backgrounds on protein stability. This work demonstrates the potential for using stably expressed tFTs to study native protein dynamics with high temporal resolution in response to exogenous or endogenous stimuli.
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Affiliation(s)
- Hongtao Zhang
- Plant Sciences Department, Rothamsted Research, Harpenden AL5 2JQ, United Kingdom
| | - Eric Linster
- Centre for Organismal Studies, University of Heidelberg, Heidelberg 69120, Germany
| | - Lucy Gannon
- Plant Sciences Department, Rothamsted Research, Harpenden AL5 2JQ, United Kingdom
| | - Wiebke Leemhuis
- Centre for Organismal Studies, University of Heidelberg, Heidelberg 69120, Germany
| | - Chelsea A Rundle
- Plant Sciences Department, Rothamsted Research, Harpenden AL5 2JQ, United Kingdom
| | | | - Markus Wirtz
- Centre for Organismal Studies, University of Heidelberg, Heidelberg 69120, Germany
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6
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Zhang H, Gannon L, Jones PD, Rundle CA, Hassall KL, Gibbs DJ, Holdsworth MJ, Theodoulou FL. Genetic interactions between ABA signalling and the Arg/N-end rule pathway during Arabidopsis seedling establishment. Sci Rep 2018; 8:15192. [PMID: 30315202 PMCID: PMC6185960 DOI: 10.1038/s41598-018-33630-5] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2018] [Accepted: 10/01/2018] [Indexed: 11/25/2022] Open
Abstract
The Arg/N-end rule pathway of ubiquitin-mediated proteolysis has multiple functions throughout plant development, notably in the transition from dormant seed to photoautotrophic seedling. PROTEOLYSIS6 (PRT6), an N-recognin E3 ligase of the Arg/N-end rule regulates the degradation of transcription factor substrates belonging to Group VII of the Ethylene Response Factor superfamily (ERFVIIs). It is not known whether ERFVIIs are associated with all known functions of the Arg/N-end rule, and the downstream pathways influenced by ERFVIIs are not fully defined. Here, we examined the relationship between PRT6 function, ERFVIIs and ABA signalling in Arabidopsis seedling establishment. Physiological analysis of seedlings revealed that N-end rule-regulated stabilisation of three of the five ERFVIIs, RAP2.12, RAP2.2 and RAP2.3, controls sugar sensitivity of seedling establishment and oil body breakdown following germination. ABA signalling components ABA INSENSITIVE (ABI)4 as well as ABI3 and ABI5 were found to enhance ABA sensitivity of germination and sugar sensitivity of establishment in a background containing stabilised ERFVIIs. However, N-end rule regulation of oil bodies was not dependent on canonical ABA signalling. We propose that the N-end rule serves to control multiple aspects of the seed to seedling transition by regulation of ERFVII activity, involving both ABA-dependent and independent signalling pathways.
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Affiliation(s)
- Hongtao Zhang
- Plant Sciences Department, Rothamsted Research, Harpenden, AL5 2JQ, UK
| | - Lucy Gannon
- Plant Sciences Department, Rothamsted Research, Harpenden, AL5 2JQ, UK
| | - Peter D Jones
- School of Biosciences, University of Nottingham, Loughborough, LE12 5RD, UK.,Department of Cardiovascular Sciences, University of Leicester, Leicester, LE3 7QP, UK
| | - Chelsea A Rundle
- Plant Sciences Department, Rothamsted Research, Harpenden, AL5 2JQ, UK
| | - Kirsty L Hassall
- Computational and Analytical Sciences Department, Rothamsted Research, Harpenden, AL5 2JQ, UK
| | - Daniel J Gibbs
- School of Biosciences, University of Birmingham, Edgbaston, B15 2TT, UK
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7
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Hearn TJ, Marti Ruiz MC, Abdul-Awal SM, Wimalasekera R, Stanton CR, Haydon MJ, Theodoulou FL, Hannah MA, Webb AAR. BIG Regulates Dynamic Adjustment of Circadian Period in Arabidopsis thaliana. Plant Physiol 2018; 178:358-371. [PMID: 29997180 PMCID: PMC6130016 DOI: 10.1104/pp.18.00571] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/14/2018] [Accepted: 06/28/2018] [Indexed: 05/26/2023]
Abstract
Circadian clocks drive rhythms with a period near 24 h, but the molecular basis of the regulation of the period of the circadian clockis poorly understood. We previously demonstrated that metabolites affect the free-running period of the circadian oscillator of Arabidopsis (Arabidopsis thaliana), with endogenous sugars acting as an accelerator and exogenous nicotinamide acting as a brake. Changes in circadian oscillator period are thought to adjust the timing of biological activities through the process of entrainment, in which the circadian oscillator becomes synchronized to rhythmic signals such as light and dark cycles as well as changes in internal metabolism. To identify the molecular components associated with the dynamic adjustment of circadian period, we performed a forward genetic screen. We identified Arabidopsis mutants that were either period insensitive to nicotinamide (sin) or period oversensitive to nicotinamide (son). We mapped son1 to BIG, a gene of unknown molecular function that was shown previously to play a role in light signaling. We found that son1 has an early entrained phase, suggesting that the dynamic alteration of circadian period contributes to the correct timing of biological events. Our data provide insight into how the dynamic period adjustment of circadian oscillators contributes to establishing a correct phase relationship with the environment and show that BIG is involved in this process.
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Affiliation(s)
- Timothy J Hearn
- Department of Plant Sciences, University of Cambridge, Cambridge CB2 3EA, United Kingdom
| | - Maria C Marti Ruiz
- Department of Plant Sciences, University of Cambridge, Cambridge CB2 3EA, United Kingdom
| | - S M Abdul-Awal
- Department of Plant Sciences, University of Cambridge, Cambridge CB2 3EA, United Kingdom
- Biotechnology and Genetic Engineering Discipline, Khulna University, Khulna-9208, Bangladesh
| | - Rinukshi Wimalasekera
- Department of Plant Sciences, University of Cambridge, Cambridge CB2 3EA, United Kingdom
| | - Camilla R Stanton
- Department of Plant Sciences, University of Cambridge, Cambridge CB2 3EA, United Kingdom
| | - Michael J Haydon
- School of BioSciences, University of Melbourne, Melbourne, Victoria 3010, Australia
| | | | | | - Alex A R Webb
- Department of Plant Sciences, University of Cambridge, Cambridge CB2 3EA, United Kingdom
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8
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Zhang H, Gannon L, Hassall KL, Deery MJ, Gibbs DJ, Holdsworth MJ, van der Hoorn RAL, Lilley KS, Theodoulou FL. N-terminomics reveals control of Arabidopsis seed storage proteins and proteases by the Arg/N-end rule pathway. New Phytol 2018; 218:1106-1126. [PMID: 29168982 PMCID: PMC5947142 DOI: 10.1111/nph.14909] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/06/2017] [Accepted: 10/23/2017] [Indexed: 05/04/2023]
Abstract
The N-end rule pathway of targeted protein degradation is an important regulator of diverse processes in plants but detailed knowledge regarding its influence on the proteome is lacking. To investigate the impact of the Arg/N-end rule pathway on the proteome of etiolated seedlings, we used terminal amine isotopic labelling of substrates with tandem mass tags (TMT-TAILS) for relative quantification of N-terminal peptides in prt6, an Arabidopsis thaliana N-end rule mutant lacking the E3 ligase PROTEOLYSIS6 (PRT6). TMT-TAILS identified over 4000 unique N-terminal peptides representing c. 2000 protein groups. Forty-five protein groups exhibited significantly increased N-terminal peptide abundance in prt6 seedlings, including cruciferins, major seed storage proteins, which were regulated by Group VII Ethylene Response Factor (ERFVII) transcription factors, known substrates of PRT6. Mobilisation of endosperm α-cruciferin was delayed in prt6 seedlings. N-termini of several proteases were downregulated in prt6, including RD21A. RD21A transcript, protein and activity levels were downregulated in a largely ERFVII-dependent manner. By contrast, cathepsin B3 protein and activity were upregulated by ERFVIIs independent of transcript. We propose that the PRT6 branch of the pathway regulates protease activities in a complex manner and optimises storage reserve mobilisation in the transition from seed to seedling via control of ERFVII action.
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Affiliation(s)
- Hongtao Zhang
- Plant Sciences DepartmentRothamsted ResearchHarpendenAL5 2JQUK
- Cambridge Centre for ProteomicsDepartment of Biochemistry and Cambridge Systems Biology CentreUniversity of CambridgeCambridge, CB2 1QRUK
| | - Lucy Gannon
- Plant Sciences DepartmentRothamsted ResearchHarpendenAL5 2JQUK
| | - Kirsty L. Hassall
- Computational and Analytical Sciences DepartmentRothamsted ResearchHarpendenAL5 2JQUK
| | - Michael J. Deery
- Cambridge Centre for ProteomicsDepartment of Biochemistry and Cambridge Systems Biology CentreUniversity of CambridgeCambridge, CB2 1QRUK
| | - Daniel J. Gibbs
- School of BiosciencesUniversity of BirminghamEdgbastonB15 2TTUK
| | | | | | - Kathryn S. Lilley
- Cambridge Centre for ProteomicsDepartment of Biochemistry and Cambridge Systems Biology CentreUniversity of CambridgeCambridge, CB2 1QRUK
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9
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Zhang H, Deery MJ, Gannon L, Powers SJ, Lilley KS, Theodoulou FL. Quantitative proteomics analysis of the Arg/N-end rule pathway of targeted degradation in Arabidopsis roots. Proteomics 2015; 15:2447-57. [PMID: 25728785 PMCID: PMC4692092 DOI: 10.1002/pmic.201400530] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2014] [Revised: 01/29/2015] [Accepted: 02/24/2015] [Indexed: 12/03/2022]
Abstract
According to the Arg/N-end rule pathway, proteins with basic N-termini are targeted for degradation by the Arabidopsis thaliana E3 ligase, PROTEOLYSIS6 (PRT6). Proteins can also become PRT6 substrates following post-translational arginylation by arginyltransferases ATE1 and 2. Here, we undertook a quantitative proteomics study of Arg/N-end rule mutants, ate1/2 and prt6, to investigate the impact of this pathway on the root proteome. Tandem mass tag labelling identified a small number of proteins with increased abundance in the mutants, some of which represent downstream targets of transcription factors known to be N-end rule substrates. Isolation of N-terminal peptides using terminal amine isotope labelling of samples (TAILS) combined with triple dimethyl labelling identified 1465 unique N-termini. Stabilising residues were over-represented among the free neo-N-termini, but destabilising residues were not markedly enriched in N-end rule mutants. The majority of free neo-N-termini were revealed following cleavage of organellar targeting signals, thus compartmentation may account in part for the presence of destabilising residues in the wild-type N-terminome. Our data suggest that PRT6 does not have a marked impact on the global proteome of Arabidopsis roots and is likely involved in the controlled degradation of relatively few regulatory proteins. All MS data have been deposited in the ProteomeXchange with identifier PXD001719 (http://proteomecentral.proteomexchange.org/dataset/PXD001719).
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Affiliation(s)
- Hongtao Zhang
- Biological Chemistry and Crop Protection Department, Rothamsted Research, Harpenden, UK.,Cambridge Centre for Proteomics, Cambridge Systems Biology Centre, University of Cambridge, Cambridge, UK
| | - Michael J Deery
- Cambridge Centre for Proteomics, Cambridge Systems Biology Centre, University of Cambridge, Cambridge, UK
| | - Lucy Gannon
- Biological Chemistry and Crop Protection Department, Rothamsted Research, Harpenden, UK
| | - Stephen J Powers
- Computational and Systems Biology Department, Rothamsted Research, Harpenden, UK
| | - Kathryn S Lilley
- Cambridge Centre for Proteomics, Cambridge Systems Biology Centre, University of Cambridge, Cambridge, UK
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10
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de Marcos Lousa C, Dietrich D, Johnson B, Baldwin S, Holdsworth M, Theodoulou FL, Baker A. The NBDs that wouldn't die. Commun Integr Biol 2014. [DOI: 10.4161/cib.7621] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
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11
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Mendiondo GM, Medhurst A, van Roermund CW, Zhang X, Devonshire J, Scholefield D, Fernández J, Axcell B, Ramsay L, Waterham HR, Waugh R, Theodoulou FL, Holdsworth MJ. Barley has two peroxisomal ABC transporters with multiple functions in β-oxidation. J Exp Bot 2014; 65:4833-47. [PMID: 24913629 PMCID: PMC4144768 DOI: 10.1093/jxb/eru243] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
In oilseed plants, peroxisomal β-oxidation functions not only in lipid catabolism but also in jasmonate biosynthesis and metabolism of pro-auxins. Subfamily D ATP-binding cassette (ABC) transporters mediate import of β-oxidation substrates into the peroxisome, and the Arabidopsis ABCD protein, COMATOSE (CTS), is essential for this function. Here, the roles of peroxisomal ABCD transporters were investigated in barley, where the main storage compound is starch. Barley has two CTS homologues, designated HvABCD1 and HvABCD2, which are widely expressed and present in embryo and aleurone tissues during germination. Suppression of both genes in barley RNA interference (RNAi) lines indicated roles in metabolism of 2,4-dichlorophenoxybutyrate (2,4-DB) and indole butyric acid (IBA), jasmonate biosynthesis, and determination of grain size. Transformation of the Arabidopsis cts-1 null mutant with HvABCD1 and HvABCD2 confirmed these findings. HvABCD2 partially or completely complemented all tested phenotypes of cts-1. In contrast, HvABCD1 failed to complement the germination and establishment phenotypes of cts-1 but increased the sensitivity of hypocotyls to 100 μM IBA and partially complemented the seed size phenotype. HvABCD1 also partially complemented the yeast pxa1/pxa2Δ mutant for fatty acid β-oxidation. It is concluded that the core biochemical functions of peroxisomal ABC transporters are largely conserved between oilseeds and cereals but that their physiological roles and importance may differ.
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Affiliation(s)
- Guillermina M Mendiondo
- Division of Plant and Crop Sciences, School of Biosciences, University of Nottingham, Sutton Bonington Campus, Loughborough LE12 5RD, UK
| | - Anne Medhurst
- Division of Plant and Crop Sciences, School of Biosciences, University of Nottingham, Sutton Bonington Campus, Loughborough LE12 5RD, UK
| | - Carlo W van Roermund
- Laboratory of Genetic Metabolic Diseases, Academic Medical Centre, University of Amsterdam, 1105 AZ, Amsterdam, The Netherlands
| | - Xuebin Zhang
- Biological Chemistry and Crop Protection Department, Rothamsted Research, Harpenden AL5 2JQ, UK
| | - Jean Devonshire
- Plant Biology and Crop Science Department, Rothamsted Research, Harpenden AL5 2JQ, UK
| | - Duncan Scholefield
- Division of Plant and Crop Sciences, School of Biosciences, University of Nottingham, Sutton Bonington Campus, Loughborough LE12 5RD, UK
| | - José Fernández
- Division of Plant and Crop Sciences, School of Biosciences, University of Nottingham, Sutton Bonington Campus, Loughborough LE12 5RD, UK
| | - Barry Axcell
- SABMiller plc., SABMiller House, Church Street, West Woking, Surrey GU21 6HS, UK
| | - Luke Ramsay
- Division of Plant Sciences, College of life Sciences, University of Dundee and The James Hutton Institute, Invergowrie, Dundee DD2 5DA, UK
| | - Hans R Waterham
- Laboratory of Genetic Metabolic Diseases, Academic Medical Centre, University of Amsterdam, 1105 AZ, Amsterdam, The Netherlands
| | - Robbie Waugh
- Division of Plant Sciences, College of life Sciences, University of Dundee and The James Hutton Institute, Invergowrie, Dundee DD2 5DA, UK
| | - Frederica L Theodoulou
- Biological Chemistry and Crop Protection Department, Rothamsted Research, Harpenden AL5 2JQ, UK
| | - Michael J Holdsworth
- Division of Plant and Crop Sciences, School of Biosciences, University of Nottingham, Sutton Bonington Campus, Loughborough LE12 5RD, UK
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12
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Gibbs DJ, Md Isa N, Movahedi M, Lozano-Juste J, Mendiondo GM, Berckhan S, Marín-de la Rosa N, Vicente Conde J, Sousa Correia C, Pearce SP, Bassel GW, Hamali B, Talloji P, Tomé DFA, Coego A, Beynon J, Alabadí D, Bachmair A, León J, Gray JE, Theodoulou FL, Holdsworth MJ. Nitric oxide sensing in plants is mediated by proteolytic control of group VII ERF transcription factors. Mol Cell 2014; 53:369-79. [PMID: 24462115 PMCID: PMC3969242 DOI: 10.1016/j.molcel.2013.12.020] [Citation(s) in RCA: 241] [Impact Index Per Article: 24.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2013] [Revised: 11/14/2013] [Accepted: 12/13/2013] [Indexed: 11/28/2022]
Abstract
Nitric oxide (NO) is an important signaling compound in prokaryotes and eukaryotes. In plants, NO regulates critical developmental transitions and stress responses. Here, we identify a mechanism for NO sensing that coordinates responses throughout development based on targeted degradation of plant-specific transcriptional regulators, the group VII ethylene response factors (ERFs). We show that the N-end rule pathway of targeted proteolysis targets these proteins for destruction in the presence of NO, and we establish them as critical regulators of diverse NO-regulated processes, including seed germination, stomatal closure, and hypocotyl elongation. Furthermore, we define the molecular mechanism for NO control of germination and crosstalk with abscisic acid (ABA) signaling through ERF-regulated expression of ABSCISIC ACID INSENSITIVE5 (ABI5). Our work demonstrates how NO sensing is integrated across multiple physiological processes by direct modulation of transcription factor stability and identifies group VII ERFs as central hubs for the perception of gaseous signals in plants.
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Affiliation(s)
- Daniel J Gibbs
- Division of Plant and Crop Sciences, School of Biosciences, University of Nottingham, Loughborough LE12 5RD, UK
| | - Nurulhikma Md Isa
- Division of Plant and Crop Sciences, School of Biosciences, University of Nottingham, Loughborough LE12 5RD, UK
| | - Mahsa Movahedi
- Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield S10 2TN, UK
| | - Jorge Lozano-Juste
- Instituto de Biología Molecular y Celular de Plantas, Consejo Superior de Investigaciones Científicas-Universidad Politécnica de Valencia, Ciudad Politécnica de la Innovación, 46022 Valencia, Spain
| | - Guillermina M Mendiondo
- Division of Plant and Crop Sciences, School of Biosciences, University of Nottingham, Loughborough LE12 5RD, UK
| | - Sophie Berckhan
- Division of Plant and Crop Sciences, School of Biosciences, University of Nottingham, Loughborough LE12 5RD, UK
| | - Nora Marín-de la Rosa
- Instituto de Biología Molecular y Celular de Plantas, Consejo Superior de Investigaciones Científicas-Universidad Politécnica de Valencia, Ciudad Politécnica de la Innovación, 46022 Valencia, Spain
| | - Jorge Vicente Conde
- Division of Plant and Crop Sciences, School of Biosciences, University of Nottingham, Loughborough LE12 5RD, UK
| | - Cristina Sousa Correia
- Division of Plant and Crop Sciences, School of Biosciences, University of Nottingham, Loughborough LE12 5RD, UK
| | - Simon P Pearce
- Division of Plant and Crop Sciences, School of Biosciences, University of Nottingham, Loughborough LE12 5RD, UK
| | - George W Bassel
- Division of Plant and Crop Sciences, School of Biosciences, University of Nottingham, Loughborough LE12 5RD, UK
| | - Bulut Hamali
- Department of Biochemistry and Cell Biology, Max F. Perutz Laboratories, University of Vienna, Dr. Bohr Gasse 9, Vienna 1030, Austria
| | - Prabhavathi Talloji
- Department of Biochemistry and Cell Biology, Max F. Perutz Laboratories, University of Vienna, Dr. Bohr Gasse 9, Vienna 1030, Austria
| | - Daniel F A Tomé
- School of Life Sciences, University of Warwick, Coventry CV4 7AL, UK
| | - Alberto Coego
- Instituto de Biología Molecular y Celular de Plantas, Consejo Superior de Investigaciones Científicas-Universidad Politécnica de Valencia, Ciudad Politécnica de la Innovación, 46022 Valencia, Spain
| | - Jim Beynon
- School of Life Sciences, University of Warwick, Coventry CV4 7AL, UK
| | - David Alabadí
- Instituto de Biología Molecular y Celular de Plantas, Consejo Superior de Investigaciones Científicas-Universidad Politécnica de Valencia, Ciudad Politécnica de la Innovación, 46022 Valencia, Spain
| | - Andreas Bachmair
- Department of Biochemistry and Cell Biology, Max F. Perutz Laboratories, University of Vienna, Dr. Bohr Gasse 9, Vienna 1030, Austria
| | - José León
- Instituto de Biología Molecular y Celular de Plantas, Consejo Superior de Investigaciones Científicas-Universidad Politécnica de Valencia, Ciudad Politécnica de la Innovación, 46022 Valencia, Spain
| | - Julie E Gray
- Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield S10 2TN, UK
| | - Frederica L Theodoulou
- Biological Chemistry and Crop Protection Department, Rothamsted Research, Harpenden AL5 2JQ, UK
| | - Michael J Holdsworth
- Division of Plant and Crop Sciences, School of Biosciences, University of Nottingham, Loughborough LE12 5RD, UK.
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13
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Abstract
Tremendous progress in plant peroxisome research has revealed unexpected metabolic functions for plant peroxisomes. Besides photorespiration and lipid metabolism, plant peroxisomes play a key role in many metabolic and signaling pathways, such as biosynthesis of phytohormones, pathogen defense, senescence-associated processes, biosynthesis of biotin and isoprenoids, and metabolism of urate, polyamines, sulfite, phylloquinone, volatile benzenoids, and branched chain amino acids. These peroxisomal pathways require an interplay with other cellular compartments, including plastids, mitochondria, and the cytosol. Consequently, a considerable number of substrates, intermediates, end products, and cofactors have to shuttle across peroxisome membranes. However, our knowledge of their membrane passage is still quite limited. This review describes the solute transport processes required to connect peroxisomes with other cell compartments. Furthermore, we discuss the known and yet-to-be-defined transport proteins that mediate these metabolic exchanges across the peroxisomal bilayer.
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Affiliation(s)
- Nicole Linka
- Department of Plant Biochemistry, Heinrich Heine University Düsseldorf, Universitätsstrasse 1, 40225, Düsseldorf, Germany,
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14
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Nyathi Y, Zhang X, Baldwin JM, Bernhardt K, Johnson B, Baldwin SA, Theodoulou FL, Baker A. Pseudo half-molecules of the ABC transporter, COMATOSE, bind Pex19 and target to peroxisomes independently but are both required for activity. FEBS Lett 2012; 586:2280-6. [PMID: 22710125 DOI: 10.1016/j.febslet.2012.05.065] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2012] [Accepted: 05/30/2012] [Indexed: 11/25/2022]
Abstract
Peroxisomal ABC transporters of animals and fungi are "half-size" proteins which dimerise to form a functional transporter. However, peroxisomal ABC transporters of land plants are synthesised as a single polypeptide which represents a fused heterodimer. The N- and C-terminal pseudo-halves of COMATOSE (CTS; AtABCD1) were expressed as separate polypeptides which bound Pex19 in vitro and targeted independently to the peroxisome membrane in yeast, where they were stable but not functional. When co-expressed, the pseudo-halves were fully functional as indicated by ATPase activity and rescue of the pxa1pxa2Δ mutant for growth on oleate. The functional significance of heterodimer asymmetry is discussed.
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Affiliation(s)
- Yvonne Nyathi
- Centre for Plant Sciences, Irene Manton Building, University of Leeds, Leeds LS2 9JT, UK
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15
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Abstract
The transition from seed to seedling is an important step in the life cycle of plants, which is fuelled primarily by the breakdown of triacylglycerol (TAG) in 'oilseed' species. TAG is stored within cytosolic oil bodies, while the pathway for fatty acid β-oxidation resides in the peroxisome. Although the enzymology of fatty acid β-oxidation has been relatively well characterised, the processes by which fatty acids are liberated from oil bodies and enter the peroxisome are less well understood and, together with metabolite, cofactor and co-substrate transporters, represent key targets for future research in order to understand co-ordination of peroxisomal metabolism with that of other subcellular compartments.
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Affiliation(s)
- Frederica L Theodoulou
- Biological Chemistry and Crop Protection Department, Rothamsted Research, West Common, Harpenden, Hertfordshire, UK
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16
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Kemp S, Theodoulou FL, Wanders RJA. Mammalian peroxisomal ABC transporters: from endogenous substrates to pathology and clinical significance. Br J Pharmacol 2012; 164:1753-66. [PMID: 21488864 DOI: 10.1111/j.1476-5381.2011.01435.x] [Citation(s) in RCA: 76] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Peroxisomes are indispensable organelles in higher eukaryotes. They are essential for a number of important metabolic pathways, including fatty acid α- and β-oxidation, and biosynthesis of etherphospholipids and bile acids. However, the peroxisomal membrane forms an impermeable barrier to these metabolites. Therefore, peroxisomes need specific transporter proteins to transfer these metabolites across their membranes. The mammalian peroxisomal membrane harbours three ATP-binding cassette (ABC) transporters. In recent years, significant progress has been made in unravelling the functions of these ABC transporters. There is ample evidence that they are involved in the transport of very long-chain fatty acids, pristanic acid, di- and trihydroxycholestanoic acid, dicarboxylic acids and tetracosahexaenoic acid (C24:6ω3). Surprisingly, only one disease is associated with a deficiency of a peroxisomal ABC transporter. Mutations in the ABCD1 gene encoding the peroxisomal ABC transporter adrenoleukodystrophy protein are the cause for X-linked adrenoleukodystrophy, an inherited metabolic storage disorder. This review describes the current state of knowledge on the mammalian peroxisomal ABC transporters with a particular focus on their function in metabolite transport.
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Affiliation(s)
- Stephan Kemp
- Academic Medical Center, University of Amsterdam, Amsterdam, the Netherlands.
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17
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Salleh FM, Evans K, Goodall B, Machin H, Mowla SB, Mur LAJ, Runions J, Theodoulou FL, Foyer CH, Rogers HJ. A novel function for a redox-related LEA protein (SAG21/AtLEA5) in root development and biotic stress responses. Plant Cell Environ 2012; 35:418-29. [PMID: 21736589 DOI: 10.1111/j.1365-3040.2011.02394.x] [Citation(s) in RCA: 73] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
SAG21/AtLEA5 belongs to the late embryogenesis-associated (LEA) protein family. Although it has been implicated in growth and redox responses, its precise roles remain obscure. To address this problem, we characterized root and shoot development and response to biotic stress in SAG21/AtLEA5 over-expressor (OEX) and antisense (AS) lines. AS lines exhibited earlier flowering and senescence and reduced shoot biomass. Primary root length was reduced in AS lines, as was the number of laterals relative to the primary root. Root hair number was unchanged but root hair length was proportional to SAG21/AtLEA5 expression level, with longer root hairs in OEX lines and shorter root hairs in AS, relative to wild type. Growth of the fungal nectroph, Botrytis cinerea and of a virulent bacterial pathogen (Pseudomonas syringae pv. tomato) was affected by SAG21/AtLEA5 expression; however, growth of an avirulent P.syringae strain was unaffected. A SAG21/AtLEA5-YFP fusion was localized to mitochondria, raising the intriguing possibility that SAG21 interacts with proteins involved in mitochondrial ROS signalling, which in turn, impacts on root development and pathogen responses.
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Affiliation(s)
- Faezah Mohd Salleh
- School of Biological Sciences, Cardiff University, Cardiff, CF10 3TL, UK
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18
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Zhang X, De Marcos Lousa C, Schutte-Lensink N, Ofman R, Wanders RJ, Baldwin SA, Baker A, Kemp S, Theodoulou FL. Conservation of targeting but divergence in function and quality control of peroxisomal ABC transporters: an analysis using cross-kingdom expression. Biochem J 2011; 436:547-57. [PMID: 21476988 DOI: 10.1042/bj20110249] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2023]
Abstract
ABC (ATP-binding cassette) subfamily D transporters are found in all eukaryotic kingdoms and are known to play essential roles in mammals and plants; however, their number, organization and physiological contexts differ. Via cross-kingdom expression experiments, we have explored the conservation of targeting, protein stability and function between mammalian and plant ABCD transporters. When expressed in tobacco epidermal cells, the mammalian ABCD proteins ALDP (adrenoleukodystrophy protein), ALDR (adrenoleukodystrophy-related protein) and PMP70 (70 kDa peroxisomal membrane protein) targeted faithfully to peroxisomes and P70R (PMP70-related protein) targeted to the ER (endoplasmic reticulum), as in the native host. The Arabidopsis thaliana peroxin AtPex19_1 interacted with human peroxisomal ABC transporters both in vivo and in vitro, providing an explanation for the fidelity of targeting. The fate of X-linked adrenoleukodystrophy disease-related mutants differed between fibroblasts and plant cells. In fibroblasts, levels of ALDP in some 'protein-absent' mutants were increased by low-temperature culture, in some cases restoring function. In contrast, all mutant ALDP proteins examined were stable and correctly targeted in plant cells, regardless of their fate in fibroblasts. ALDR complemented the seed germination defect of the Arabidopsis cts-1 mutant which lacks the peroxisomal ABCD transporter CTS (Comatose), but neither ALDR nor ALDP was able to rescue the defect in fatty acid β-oxidation in establishing seedlings. Taken together, our results indicate that the mechanism for trafficking of peroxisomal membrane proteins is shared between plants and mammals, but suggest differences in the sensing and turnover of mutant ABC transporter proteins and differences in substrate specificity and/or function.
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Affiliation(s)
- Xuebin Zhang
- Biological Chemistry Department, Rothamsted Research, Harpenden, Herts. AL5 2JQ, UK
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19
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Theodoulou FL, Zhang X, De Marcos Lousa C, Nyathi Y, Baker A. Peroxisomal Transport Systems: Roles in Signaling and Metabolism. Signaling and Communication in Plants 2011. [DOI: 10.1007/978-3-642-14369-4_12] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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20
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Nyathi Y, De Marcos Lousa C, van Roermund CW, Wanders RJA, Johnson B, Baldwin SA, Theodoulou FL, Baker A. The Arabidopsis peroxisomal ABC transporter, comatose, complements the Saccharomyces cerevisiae pxa1 pxa2Delta mutant for metabolism of long-chain fatty acids and exhibits fatty acyl-CoA-stimulated ATPase activity. J Biol Chem 2010; 285:29892-902. [PMID: 20659892 PMCID: PMC2943281 DOI: 10.1074/jbc.m110.151225] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2010] [Revised: 07/08/2010] [Indexed: 12/26/2022] Open
Abstract
The Arabidopsis ABC transporter Comatose (CTS; AtABCD1) is required for uptake into the peroxisome of a wide range of substrates for β-oxidation, but it is uncertain whether CTS itself is the transporter or if the transported substrates are free acids or CoA esters. To establish a system for its biochemical analysis, CTS was expressed in Saccharomyces cerevisiae. The plant protein was correctly targeted to yeast peroxisomes, was assembled into the membrane with its nucleotide binding domains in the cytosol, and exhibited basal ATPase activity that was sensitive to aluminum fluoride and abrogated by mutation of a conserved Walker A motif lysine residue. The yeast pxa1 pxa2Δ mutant lacks the homologous peroxisomal ABC transporter and is unable to grow on oleic acid. Consistent with its exhibiting a function in yeast akin to that in the plant, CTS rescued the oleate growth phenotype of the pxa1 pxa2Δ mutant, and restored β-oxidation of fatty acids with a range of chain lengths and varying degrees of desaturation. When expressed in yeast peroxisomal membranes, the basal ATPase activity of CTS could be stimulated by fatty acyl-CoAs but not by fatty acids. The implications of these findings for the function and substrate specificity of CTS are discussed.
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Affiliation(s)
- Yvonne Nyathi
- From the Centre for Plant Sciences, Faculty of Biological Sciences, and
| | | | - Carlo W. van Roermund
- the Departments of Pediatrics and Clinical Chemistry, Laboratory of Genetic Metabolic Diseases, Academic Medical Centre, University of Amsterdam, 1105 AZ Amsterdam, The Netherlands, and
| | - Ronald J. A. Wanders
- the Departments of Pediatrics and Clinical Chemistry, Laboratory of Genetic Metabolic Diseases, Academic Medical Centre, University of Amsterdam, 1105 AZ Amsterdam, The Netherlands, and
| | - Barbara Johnson
- From the Centre for Plant Sciences, Faculty of Biological Sciences, and
| | - Stephen A. Baldwin
- the Institute of Membrane and Systems Biology, University of Leeds, Leeds LS2 9JT, United Kingdom
| | | | - Alison Baker
- From the Centre for Plant Sciences, Faculty of Biological Sciences, and
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21
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De Marcos Lousa C, Dietrich D, Johnson B, Baldwin SA, Holdsworth MJ, Theodoulou FL, Baker A. The NBDs that wouldn't die: A cautionary tale of the use of isolated nucleotide binding domains of ABC transporters. Commun Integr Biol 2009; 2:97-99. [PMID: 19704900 PMCID: PMC2686355] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2008] [Accepted: 12/15/2008] [Indexed: 05/28/2023] Open
Abstract
COMATOSE (CTS), the plant homologue of Adrenoleukodystrophy protein, is a full length ABC transporter localized in peroxisomes. In a recent article, we reported that the two-nucleotide binding domains of CTS are not functionally equivalent in vivo. Mutations in conserved residues in the Walker A (K487A) and B (D606N) motifs of NBD1 resulted in a null phenotype, whereas identical mutations in the equivalent residues in NBD2 (K1136A and D1276N) had no detectable effect.1 In order to study the effect of these mutations on the ATPase activity of the nucleotide binding domains, we cloned and expressed the isolated NBDs as maltose binding protein (MBP) fusion proteins. We show that ATPase activity is associated with the isolated MBP-NBDs. However, mutations of amino acids located in conserved motifs did not result in striking reduction in activity despite well characterized roles in ATP binding and hydrolysis.2 We urge caution in the interpretation of results obtained from the study of isolated NBD fusions and their extrapolation to the mechanism of ATP hydrolysis in ABC transporter proteins.
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Affiliation(s)
| | - Daniela Dietrich
- Division of Plant and Crop Science; University of Nottingham; Loughborough, UK
| | | | - Stephen A Baldwin
- Institute of Membrane and Systems Biology; University of Leeds; Leeds, UK
| | | | | | - Alison Baker
- Centre for Plant Sciences; University of Leeds; Leeds, UK
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22
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Linka N, Theodoulou FL, Haslam RP, Linka M, Napier JA, Neuhaus HE, Weber APM. Peroxisomal ATP import is essential for seedling development in Arabidopsis thaliana. Plant Cell 2008; 20:3241-57. [PMID: 19073763 PMCID: PMC2630453 DOI: 10.1105/tpc.108.062042] [Citation(s) in RCA: 87] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
Several recent proteomic studies of plant peroxisomes indicate that the peroxisomal matrix harbors multiple ATP-dependent enzymes and chaperones. However, it is unknown whether plant peroxisomes are able to produce ATP by substrate-level phosphorylation or whether external ATP fuels the energy-dependent reactions within peroxisomes. The existence of transport proteins that supply plant peroxisomes with energy for fatty acid oxidation and other ATP-dependent processes has not previously been demonstrated. Here, we describe two Arabidopsis thaliana genes that encode peroxisomal adenine nucleotide carriers, PNC1 and PNC2. Both proteins, when fused to enhanced yellow fluorescent protein, are targeted to peroxisomes. Complementation of a yeast mutant deficient in peroxisomal ATP import and in vitro transport assays using recombinant transporter proteins revealed that PNC1 and PNC2 catalyze the counterexchange of ATP with ADP or AMP. Transgenic Arabidopsis lines repressing both PNC genes were generated using ethanol-inducible RNA interference. A detailed analysis of these plants showed that an impaired peroxisomal ATP import inhibits fatty acid breakdown during early seedling growth and other beta-oxidation reactions, such as auxin biosynthesis. We show conclusively that PNC1 and PNC2 are essential for supplying peroxisomes with ATP, indicating that no other ATP generating systems exist inside plant peroxisomes.
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Affiliation(s)
- Nicole Linka
- Institut für Biochemie der Pflanzen, Heinrich-Heine Universität Düsseldorf, D-40225 Düsseldorf, Germany.
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23
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Dietrich D, Schmuths H, De Marcos Lousa C, Baldwin JM, Baldwin SA, Baker A, Theodoulou FL, Holdsworth MJ. Mutations in the Arabidopsis peroxisomal ABC transporter COMATOSE allow differentiation between multiple functions in planta: insights from an allelic series. Mol Biol Cell 2008; 20:530-43. [PMID: 19019987 DOI: 10.1091/mbc.e08-07-0745] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
COMATOSE (CTS), the Arabidopsis homologue of human Adrenoleukodystrophy protein (ALDP), is required for import of substrates for peroxisomal beta-oxidation. A new allelic series and a homology model based on the bacterial ABC transporter, Sav1866, provide novel insights into structure-function relations of ABC subfamily D proteins. In contrast to ALDP, where the majority of mutations result in protein absence from the peroxisomal membrane, all CTS mutants produced stable protein. Mutation of conserved residues in the Walker A and B motifs in CTS nucleotide-binding domain (NBD) 1 resulted in a null phenotype but had little effect in NBD2, indicating that the NBDs are functionally distinct in vivo. Two alleles containing mutations in NBD1 outside the Walker motifs (E617K and C631Y) exhibited resistance to auxin precursors 2,4-dichlorophenoxybutyric acid (2,4-DB) and indole butyric acid (IBA) but were wild type in all other tests. The homology model predicted that the transmission interfaces are domain-swapped in CTS, and the differential effects of mutations in the conserved "EAA motif" of coupling helix 2 supported this prediction, consistent with distinct roles for each NBD. Our findings demonstrate that CTS functions can be separated by mutagenesis and the structural model provides a framework for interpretation of phenotypic data.
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Affiliation(s)
- Daniela Dietrich
- Department of Plant and Crop Sciences, School of Biosciences, University of Nottingham, Sutton Bonington Campus, Loughborough, United Kingdom
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24
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Verrier PJ, Bird D, Burla B, Dassa E, Forestier C, Geisler M, Klein M, Kolukisaoglu U, Lee Y, Martinoia E, Murphy A, Rea PA, Samuels L, Schulz B, Spalding EJ, Yazaki K, Theodoulou FL. Plant ABC proteins--a unified nomenclature and updated inventory. Trends Plant Sci 2008; 13:151-9. [PMID: 18299247 DOI: 10.1016/j.tplants.2008.02.001] [Citation(s) in RCA: 459] [Impact Index Per Article: 28.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/01/2007] [Revised: 01/21/2008] [Accepted: 02/14/2008] [Indexed: 05/18/2023]
Abstract
The ABC superfamily comprises both membrane-bound transporters and soluble proteins involved in a broad range of processes, many of which are of considerable agricultural, biotechnological and medical potential. Completion of the Arabidopsis and rice genome sequences has revealed a particularly large and diverse complement of plant ABC proteins in comparison with other organisms. Forward and reverse genetics, together with heterologous expression, have uncovered many novel roles for plant ABC proteins, but this progress has been accompanied by a confusing proliferation of names for plant ABC genes and their products. A consolidated nomenclature will provide much-needed clarity and a framework for future research.
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Affiliation(s)
- Paul J Verrier
- Biomathematics and Bioinformatics Department, Rothamsted Research, Harpenden, AL5 2JQ, UK
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25
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Carrera E, Holman T, Medhurst A, Dietrich D, Footitt S, Theodoulou FL, Holdsworth MJ. Seed after-ripening is a discrete developmental pathway associated with specific gene networks in Arabidopsis. Plant J 2008; 53:214-24. [PMID: 18028281 PMCID: PMC2254144 DOI: 10.1111/j.1365-313x.2007.03331.x] [Citation(s) in RCA: 118] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/02/2007] [Revised: 09/10/2007] [Accepted: 09/17/2007] [Indexed: 05/18/2023]
Abstract
After-ripening (AR) is a time and environment regulated process occurring in the dry seed, which determines the germination potential of seeds. Both metabolism and perception of the phytohormone abscisic acid (ABA) are important in the initiation and maintenance of dormancy. However, molecular mechanisms that regulate the capacity for dormancy or germination through AR are unknown. To understand the relationship between ABA and AR, we analysed genome expression in Arabidopsis thaliana mutants defective in seed ABA synthesis (aba1-1) or perception (abi1-1). Even though imbibed mutant seeds showed no dormancy, they exhibited changes in global gene expression resulting from dry AR that were comparable with changes occurring in wild-type (WT) seeds. Core gene sets were identified that were positively or negatively regulated by dry seed storage. Each set included a gene encoding repression or activation of ABA function (LPP2 and ABA1, respectively), thereby suggesting a mechanism through which dry AR may modulate subsequent germination potential in WT seeds. Application of exogenous ABA to after-ripened WT seeds did not reimpose characteristics of freshly harvested seeds on imbibed seed gene expression patterns. It was shown that secondary dormancy states reinstate AR status-specific gene expression patterns. A model is presented that separates the action of ABA in seed dormancy from AR and dry storage regulated gene expression. These results have major implications for the study of genetic mechanisms altered in seeds as a result of crop domestication into agriculture, and for seed behaviour during dormancy cycling in natural ecosystems.
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Affiliation(s)
- Esther Carrera
- Crop Performance and Improvement Division, Rothamsted ResearchHarpenden, Hertfordshire AL5 2JQ, UK
| | - Tara Holman
- Department of Agricultural and Environmental Sciences, School of BioSciences, University of NottinghamNottingham LE12 5RD, UK
| | - Anne Medhurst
- Department of Agricultural and Environmental Sciences, School of BioSciences, University of NottinghamNottingham LE12 5RD, UK
| | - Daniela Dietrich
- Crop Performance and Improvement Division, Rothamsted ResearchHarpenden, Hertfordshire AL5 2JQ, UK
- Department of Agricultural and Environmental Sciences, School of BioSciences, University of NottinghamNottingham LE12 5RD, UK
| | - Steven Footitt
- Crop Performance and Improvement Division, Rothamsted ResearchHarpenden, Hertfordshire AL5 2JQ, UK
| | - Frederica L Theodoulou
- Crop Performance and Improvement Division, Rothamsted ResearchHarpenden, Hertfordshire AL5 2JQ, UK
| | - Michael J Holdsworth
- Department of Agricultural and Environmental Sciences, School of BioSciences, University of NottinghamNottingham LE12 5RD, UK
- Correspondence (fax +44 0 1159516233; e-mail )
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26
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Footitt S, Dietrich D, Fait A, Fernie AR, Holdsworth MJ, Baker A, Theodoulou FL. The COMATOSE ATP-binding cassette transporter is required for full fertility in Arabidopsis. Plant Physiol 2007; 144:1467-80. [PMID: 17468211 PMCID: PMC1914130 DOI: 10.1104/pp.107.099903] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
COMATOSE (CTS) encodes a peroxisomal ATP-binding cassette transporter required not only for beta-oxidation of storage lipids during germination and establishment, but also for biosynthesis of jasmonic acid and conversion of indole butyric acid to indole acetic acid. cts mutants exhibited reduced fertilization, which was rescued by genetic complementation, but not by exogenous application of jasmonic acid or indole acetic acid. Reduced fertilization was also observed in thiolase (kat2-1) and peroxisomal acyl-Coenzyme A synthetase mutants (lacs6-1,lacs7-1), indicating a general role for beta-oxidation in fertility. Genetic analysis revealed reduced male transmission of cts alleles and both cts pollen germination and tube growth in vitro were impaired in the absence of an exogenous carbon source. Aniline blue staining of pollinated pistils demonstrated that pollen tube growth was affected only when both parents bore the cts mutation, indicating that expression of CTS in either male or female tissues was sufficient to support pollen tube growth in vivo. Accordingly, abundant peroxisomes were detected in a range of maternal tissues. Although gamma-aminobutyric acid levels were reduced in flowers of cts mutants, they were unchanged in kat2-1, suggesting that alterations in gamma-aminobutyric acid catabolism do not contribute to the reduced fertility phenotype through altered pollen tube targeting. Taken together, our data support an important role for beta-oxidation in fertility in Arabidopsis (Arabidopsis thaliana) and suggest that this pathway could play a role in the mobilization of lipids in both pollen and female tissues.
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Affiliation(s)
- Steven Footitt
- Crop Performance and Improvement Division, Rothamsted Research, Harpenden, Hertfordshire, UK
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Carrera E, Holman T, Medhurst A, Peer W, Schmuths H, Footitt S, Theodoulou FL, Holdsworth MJ. Gene expression profiling reveals defined functions of the ATP-binding cassette transporter COMATOSE late in phase II of germination. Plant Physiol 2007; 143:1669-79. [PMID: 17322332 PMCID: PMC1851828 DOI: 10.1104/pp.107.096057] [Citation(s) in RCA: 75] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
Phase II of germination represents a key developmental stage of plant growth during which imbibed seeds either enter stage III of germination, completing the germination process via radicle protrusion, or remain dormant. In this study, we analyzed the influence of the peroxisomal ATP-binding cassette transporter COMATOSE (CTS) on the postimbibition seed transcriptome of Arabidopsis (Arabidopsis thaliana) and also investigated interactions between gibberellin (GA) and CTS function. A novel method for analysis of transcriptome datasets allowed visualization of developmental signatures of seeds, showing that cts-1 retains the capacity to after ripen, indicating a germination block late in phase II. Expression of the key GA biosynthetic genes GA3ox1 and 2 was greatly reduced in cts seeds and genetic analysis suggested that CTS was epistatic to RGL2, a germination-repressing DELLA protein that is degraded by GA. Comparative analysis of seed transcriptome datasets indicated that specific cohorts of genes were influenced by GA and CTS. CTS function was required for expression of the flavonoid biosynthetic pathway. Confocal imaging demonstrated the exclusive accumulation of flavonoids in the epidermis of wild-type seeds. In contrast, flavonoids were absent from cts and kat2-1 mutant seeds, but accumulated following the application of sucrose, indicating an essential role for beta-oxidation in inducing flavonoid biosynthetic genes. These results demonstrate that CTS functions very late in phase II of germination and that its function is required for the expression of specific gene sets related to an important biochemical pathway associated with seedling establishment and survival.
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Affiliation(s)
- Esther Carrera
- Centro de Genomica, Instituto Valenciano de Investigaciones Agrarias, Valencia, Spain
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28
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Mowla SB, Cuypers A, Driscoll SP, Kiddle G, Thomson J, Foyer CH, Theodoulou FL. Yeast complementation reveals a role for an Arabidopsis thaliana late embryogenesis abundant (LEA)-like protein in oxidative stress tolerance. Plant J 2006; 48:743-56. [PMID: 17092320 DOI: 10.1111/j.1365-313x.2006.02911.x] [Citation(s) in RCA: 74] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
A functional cloning approach using the oxidant-sensitive yeast mutant, Deltayap1, was employed to identify plant genes involved in tolerance of oxidative stress. In this screen, we identified an Arabidopsis late embryogenesis-abundant (LEA)-like protein, AtLEA5, which increased the tolerance of Deltayap1 cells to the oxidants H(2)O(2), diamide, menadione and tert-butyl hydroperoxide. Unlike canonical LEAs, AtLEA5 is constitutively expressed in roots and reproductive organs but not in seeds. In leaves of short-day grown plants, AtLEA5 transcripts exhibited a diurnal pattern of regulation, where transcripts were repressed in the light and abundant in the dark. Expression of AtLEA5 in leaves was induced by oxidants, ABA and dehydration. Use of abi1-1 (ABA-insensitive) and aba1-1 (ABA-deficient) Arabidopsis mutants indicated that drought induction of AtLEA5 required ABA synthesis but was independent of the ABI1 gene product. Abscisic acid and H(2)O(2) induction of AtLEA5 was also independent of the OXI1 protein kinase. Constitutive overexpression of AtLEA5 resulted in increased root growth and shoot biomass, both in optimal conditions and under H(2)O(2) stress. However, in comparison with wild type, photosynthesis in overexpressing plants was more susceptible to drought. These features suggest that AtLEA5 has a unique function among LEA proteins in that it plays a specific role in protection against oxidative stress involving decreased photosynthesis. This protein functions as part of a complex network of defences that contribute to robustness of plants under stress by minimizing the negative effects of oxidation.
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Affiliation(s)
- Shaheen B Mowla
- Crop Performance and Improvement Division, Rothamsted Research, Harpenden, Herts AL5 2JQ, UK
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29
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Rottensteiner H, Theodoulou FL. The ins and outs of peroxisomes: Co-ordination of membrane transport and peroxisomal metabolism. Biochimica et Biophysica Acta (BBA) - Molecular Cell Research 2006; 1763:1527-40. [PMID: 17010456 DOI: 10.1016/j.bbamcr.2006.08.012] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/23/2006] [Revised: 08/15/2006] [Accepted: 08/18/2006] [Indexed: 11/28/2022]
Abstract
Peroxisomes perform a range of metabolic functions which require the movement of substrates, co-substrates, cofactors and metabolites across the peroxisomal membrane. In this review, we discuss the evidence for and against specific transport systems involved in peroxisomal metabolism and how these operate to co-ordinate biochemical reactions within the peroxisome with those in other compartments of the cell.
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Affiliation(s)
- Hanspeter Rottensteiner
- Medical Faculty of the Ruhr-University of Bochum, Department of Physiological Chemistry, Section of Systems Biochemistry, 44780 Bochum, Germany.
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30
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Baker A, Graham IA, Holdsworth M, Smith SM, Theodoulou FL. Chewing the fat: beta-oxidation in signalling and development. Trends Plant Sci 2006; 11:124-32. [PMID: 16490379 DOI: 10.1016/j.tplants.2006.01.005] [Citation(s) in RCA: 81] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/11/2005] [Revised: 12/01/2005] [Accepted: 01/30/2006] [Indexed: 05/06/2023]
Abstract
Peroxisomal beta-oxidation is involved not only in fatty acid catabolism and lipid housekeeping but also in metabolism of hormones and amino acids in plants. Recent research in model species has led to new insights into the roles of this pathway in signalling and development, in particular regarding the involvement of beta-oxidation in jasmonic acid biosynthesis. Analysis of associated processes, such as the glyoxylate cycle and redox metabolism has also highlighted the importance of integration of beta-oxidation with cytosolic and mitochondrial metabolism. Mutations that disrupt beta-oxidation can have extremely pleiotropic effects, indicating important and varied roles for this pathway throughout the plant life cycle and making this an exciting topic for future research.
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Affiliation(s)
- Alison Baker
- Centre for Plant Sciences, University of Leeds, Leeds LS2 9JT, UK.
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31
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Abstract
Peroxisomes perform a range of different functions, dependent upon organism, tissue type, developmental stage or environmental conditions, many of which are connected with lipid metabolism. This review summarises recent research on ATP binding cassette (ABC) transporters of the peroxisomal membrane (ABC subfamily D) and their roles in plants, fungi and animals. Analysis of mutants has revealed that peroxisomal ABC transporters play key roles in specific metabolic and developmental functions in different organisms. A common function is import of substrates for beta-oxidation but much remains to be determined concerning transport substrates and mechanisms which appear to differ significantly between phyla.
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Affiliation(s)
- Frederica L Theodoulou
- Crop Performance and Improvement Division, Rothamsted Research, Harpenden, Hertfordshire AL5 2JQ, United Kingdom.
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32
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Footitt S, Marquez J, Schmuths H, Baker A, Theodoulou FL, Holdsworth M. Analysis of the role of COMATOSE and peroxisomal beta-oxidation in the determination of germination potential in Arabidopsis. J Exp Bot 2006; 57:2805-14. [PMID: 16844736 DOI: 10.1093/jxb/erl045] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
Comparative physiological analysis of mutant Arabidopsis seeds under defined environmental conditions was used to analyse the relative contributions of components of peroxisomal beta-oxidation in the control of seed germination potential. The COMATOSE (CTS) and KAT2 loci were shown to play essential roles in regulating germination and establishment potentials, whereas LACS6 and LACS7 loci only influenced establishment following germination. The viability and desiccation tolerance of three different mutant alleles of CTS were shown to be intermediate between that of dormant and non-dormant wild-type seeds. Analysis of ttg-1 cts-1 double mutant seeds demonstrated that the cts lesion did not influence after-ripening capacity. These data demonstrate the importance of peroxisomal beta-oxidation in the control of germination potential, but suggest that breakdown of stored lipid is not an important prerequisite for germination. A function is suggested for CTS following after-ripening within pathways related to the progression of germination prior to radicle emergence.
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Affiliation(s)
- Steven Footitt
- Crop Performance and Improvement Division, Rothamsted Research, Harpenden, Hertfordshire AL5 2JQ, UK
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33
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Theodoulou FL, Job K, Slocombe SP, Footitt S, Holdsworth M, Baker A, Larson TR, Graham IA. Jasmonic acid levels are reduced in COMATOSE ATP-binding cassette transporter mutants. Implications for transport of jasmonate precursors into peroxisomes. Plant Physiol 2005; 137:835-40. [PMID: 15761209 PMCID: PMC1065384 DOI: 10.1104/pp.105.059352] [Citation(s) in RCA: 173] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/05/2005] [Revised: 01/13/2005] [Accepted: 01/13/2005] [Indexed: 05/18/2023]
Affiliation(s)
- Frederica L Theodoulou
- Crop Performance and Improvement Division, Rothamsted Research, Harpenden, Hertfordshire AL5 2JQ, United Kingdom.
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34
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Affiliation(s)
- F L Theodoulou
- Biochemistry and Physiology Department, AFRC Institute of Arable Crops Research, Harpenden, UK
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35
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Mittova V, Theodoulou FL, Kiddle G, Gómez L, Volokita M, Tal M, Foyer CH, Guy M. Coordinate induction of glutathione biosynthesis and glutathione-metabolizing enzymes is correlated with salt tolerance in tomato. FEBS Lett 2003; 554:417-21. [PMID: 14623104 DOI: 10.1016/s0014-5793(03)01214-6] [Citation(s) in RCA: 84] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
The acclimation of reduced glutathione (GSH) biosynthesis and GSH-utilizing enzymes to salt stress was studied in two tomato species that differ in stress tolerance. Salt increased GSH content and GSH:GSSG (oxidized glutathione) ratio in oxidative stress-tolerant Lycopersicon pennellii (Lpa) but not in Lycopersicon esculentum (Lem). These changes were associated with salt-induced upregulation of gamma-glutamylcysteine synthetase protein, an effect which was prevented by preincubation with buthionine sulfoximine. Salt treatment induced glutathione peroxidase and glutathione-S-transferase but not glutathione reductase activities in Lpa. These results suggest a mechanism of coordinate upregulation of synthesis and metabolism of GSH in Lpa, that is absent from Lem.
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Affiliation(s)
- Valentina Mittova
- Albert Katz Department of Drylands Biotechnologies, Jacob Blaustein Institute for Desert Research, Ben-Gurion University of the Negev, Sede Boqer Campus 84990, Israel
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36
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Millar AH, Mittova V, Kiddle G, Heazlewood JL, Bartoli CG, Theodoulou FL, Foyer CH. Control of ascorbate synthesis by respiration and its implications for stress responses. Plant Physiol 2003; 133:443-7. [PMID: 14555771 PMCID: PMC1540335 DOI: 10.1104/pp.103.028399] [Citation(s) in RCA: 183] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Affiliation(s)
- A Harvey Millar
- Plant Molecular Biology Group, School of Biomedical and Chemical Sciences, University of Western Australia, Crawley 6009, Australia
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37
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Lao SH, Loutre C, Brazier M, Coleman JOD, Cole DJ, Edwards R, Theodoulou FL. 3,4-Dichloroaniline is detoxified and exported via different pathways in Arabidopsis and soybean. Phytochemistry 2003; 63:653-61. [PMID: 12842137 DOI: 10.1016/s0031-9422(03)00289-9] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
The metabolic fate of [UL-14C]-3,4-dichloroaniline (DCA) was investigated in Arabidopsis root cultures and soybean plants over a 48 h period following treatment via the root media. DCA was rapidly taken up by both species and metabolised, predominantly to N-malonyl-DCA in soybean and N-glucosyl-DCA in Arabidopsis. Synthesis occurred in the roots and the respective conjugates were largely exported into the culture medium, a smaller proportion being retained within the plant tissue. Once conjugated, the DCA metabolites in the medium were not then readily taken up by roots of either species. The difference in the routes of DCA detoxification in the two plants could be explained partly by the relative activities of the respective conjugating enzymes, soybean containing high DCA-N-malonyltransferase activity, while in Arabidopsis DCA-N-glucosyltransferase activity predominated. A pre-treatment of plants with DCA increased DCA-N-malonyltransferase activity in soybean but not in Arabidopsis, indicating differential regulation of this enzyme in the two plant species. This study demonstrates that DCA can undergo two distinct detoxification mechanisms which both lead to the export of conjugated metabolites from roots into the surrounding medium in contrast to the vacuolar deposition more commonly associated with the metabolism of xenobiotics in plants.
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Affiliation(s)
- Si-Houy Lao
- Crop Performance and Improvement Division, Rothamsted Research, Harpenden AL5 2JQ, UK
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38
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Theodoulou FL, Clark IM, He XL, Pallett KE, Cole DJ, Hallahan DL. Co-induction of glutathione-S-transferases and multidrug resistance associated protein by xenobiotics in wheat. Pest Manag Sci 2003; 59:202-14. [PMID: 12587874 DOI: 10.1002/ps.576] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Herbicide safeners are known to protect monocotyledonous crops from herbicide injury by accelerating the metabolism of herbicides. We have investigated the effects of the safener cloquintocetmexyl, which protects small-grain cereals against the graminicidal herbicide, clodinafop-propargyl. Subtractive suppression hybridisation was used to identify wheat genes which are up-regulated by treatment not only with cloquintocet-mexyl but also with phenobarbital, which is known to stimulate xenobiotic metabolism in animals and plants. DNA sequences of five glutathione transferases (GSTs) belonging to three different classes and a multidrug resistance associated protein (MRP) homologue were identified in the screen. The chemical inducibility of these clones was confirmed by Northern analysis. The MRP protein was shown to be induced by treatments with cloquintocet-mexyl and phenobarbital and to be localised to the tonoplast. Since clodinafop-propargyl is not known to be metabolised by glutathionylation, the significance of GST induction is interpreted in terms of a generalised response to chemical stress, particularly the generation of active oxygen species. This work establishes herbicide safeners as useful tools for the identification of genes encoding herbicide-metabolising enzymes.
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Abstract
Glutathione is one of the major redox buffers in most aerobic cells, and it has a broad spectrum of functions in plants. Recent discoveries implicate this thiol peptide in signalling and cellular homeostasis. Glutathione can sense intracellular redox status: perturbations of glutathione reduction state are transduced into changes in gene expression. This central role demands precise control of both the concentration and the reduction state of glutathione in different compartments. In addition to the regulation of glutathione biosynthesis and redox state, attention is now turning to the role of glutathione transporters.
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Abstract
We have expressed the CRNA high affinity nitrate transporter from Emericella (Aspergillus) nidulans in Xenopus oocytes and used electrophysiology to study its properties. This method was used because there are no convenient radiolabeled substrates for the transporter. Oocytes injected with crnA mRNA showed nitrate-, nitrite-, and chlorite-dependent currents. Although the gene was originally identified by chlorate selection there was no evidence for transport of this anion. The gene selection is explained by the high affinity of the transporter for chlorite, and the fact that this ion contaminates solutions of chlorate. The pH-dependence of the anion-elicited currents was consistent with H(+)-coupled mechanism of transport. At any given voltage, currents showed hyperbolic kinetics with respect to extracellular H(+), and these data could be fitted with a Michaelis-Menten relationship. But this equation did not adequately describe transport of the anion substrates. At higher concentrations of the anion substrates and more negative membrane voltages, the currents were decreased, but this effect was independent of changes in external pH. These more complicated kinetics could be fit by an equation containing two Michaelis-Menten terms. The substrate inhibition of the currents could be explained by a transport reaction cycle that included two routes for the transfer of nitrate across the membrane, one on the empty carrier and the other proton coupled. The model predicts that the substrate inhibition of transporter current depends on the cytosolic nitrate concentration. This is the first time a high affinity nitrate transport activity has been characterized in a heterologous system and the measurements show how the properties of the CRNA transporter are modified by changes in the membrane potential, external pH, and nitrate concentration. The physiological significance of these observations is discussed.
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Affiliation(s)
- J J Zhou
- Biochemistry and Physiology Department, Integrated Approach to Crop Research (IACR)-Rothamsted, Harpenden, Herts, AL5 2JQ, United Kingdom
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Abstract
The ATP binding cassette (ABC) superfamily is a large, ubiquitous and diverse group of proteins, most of which mediate transport across biological membranes. ABC transporters have been shown to function not only as ATP-dependent pumps, but also as ion channels and channel regulators. Whilst members of this gene family have been extensively characterised in mammalian and microbial systems, the study of plant ABC transporters is a relatively new field of investigation. Sequences of over 20 plant ABC proteins have been published and include homologues of P-glycoprotein, MRP, PDR5 and organellar transporters. At present, functions have been assigned to a small proportion of these genes and only the MRP subclass has been extensively characterised. This review aims to summarise literature relevant to the study of plant ABC transporters, to review methods of cloning, to discuss the utility of yeast and mammalian systems as models and to speculate on possible roles of uncharacterised ABC transporters in plants.
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Affiliation(s)
- F L Theodoulou
- Biochemistry and Physiology Department, IACR-Rothamsted, Harpenden, UK.
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Zhou JJ, Theodoulou FL, Muldin I, Ingemarsson B, Miller AJ. Cloning and functional characterization of a Brassica napus transporter that is able to transport nitrate and histidine. J Biol Chem 1998; 273:12017-23. [PMID: 9575142 DOI: 10.1074/jbc.273.20.12017] [Citation(s) in RCA: 122] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
A full-length cDNA for a membrane transporter was isolated from Brassica napus by its sequence homology to a previously cloned Arabidopsis low affinity nitrate transporter. The cDNA encodes a predicted protein of 589 amino acid residues with 12 putative transmembrane domains. The transporter belongs to a multigene family with members that have been identified in bacteria, fungi, plants, and animals and that are able to transport a range of different nitrogen-containing substrates, including amino acids, peptides, and nitrate. To identify the substrates of this plant gene, we have expressed the protein in Xenopus oocytes. The properties of the transporter are consistent with a proton cotransport mechanism for nitrate, and the voltage dependence of the Km for nitrate was determined. The Km for nitrate was shown to increase from 4 to 14 mM as the membrane voltage became more negative from -40 to -180 mV. Oocytes expressing the gene could accumulate internal nitrate to concentrations higher than those measured in water-injected controls. A range of different substrate molecules for the transporter was tested, but of these, histidine gave the largest currents, although the affinity was in the millimolar range. The pH dependence of the activity of the transporter was different for the substrates, with histidine transport favored at alkaline and nitrate at acid external pH. Kinetic analysis of the mechanism of histidine transport suggests a cotransport of protons and the neutral form of the amino acid, with the Km for histidine decreasing at more negative membrane voltages. This gene is the first member of this family of transporters for which the transport of two very different types of substrate, nitrate and histidine, has been demonstrated.
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Affiliation(s)
- J J Zhou
- Biochemistry and Physiology Department, Integrated Approach to Crop Research (IACR)-Rothamsted Experimental Station, Harpenden, Hertfordshire AL5 2JQ, United Kingdom
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Abstract
P-glycoproteins are members of a large superfamily of transport proteins (the 'traffic ATPases') that utilize ATP to translocate a wide range of substrates across biological membranes. Using a PCR-based approach, and degenerate oligonucleotides corresponding to conserved motifs, two 300-bp cDNA fragments (pBMDR1 and pBMDR2) with a significant sequence similarity to mammalian P-glycoproteins were amplified from barley (Hordeum vulgare) root poly A+ RNA and used as probes to screen a barley root cDNA library. A single full-length clone pHVMDR2 coding for a polypeptide of 1232 residues (c. 134 kDa) was isolated. Comparison of this barley sequence with Arabidopsis ATPGP1 and human MDR1 and MDR3 P-glycoprotein sequences showed that the barley cDNA has 44%, 37% and 38% amino acid (aa) identity, respectively, with these sequences, and conserved structural features. RNase protection analysis showed that HVMDR2 mRNA is expressed at low levels in both barley roots and leaves. Southern blot analyses indicated that there is a small multigene family related to P-glycoproteins in barley. Possible functions for these barley P-glycoproteins are discussed.
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MESH Headings
- ATP Binding Cassette Transporter, Subfamily B
- ATP Binding Cassette Transporter, Subfamily B, Member 1/chemistry
- ATP Binding Cassette Transporter, Subfamily B, Member 1/genetics
- ATP-Binding Cassette Transporters/chemistry
- ATP-Binding Cassette Transporters/genetics
- Amino Acid Sequence
- Base Sequence
- Cloning, Molecular
- DNA, Complementary/genetics
- DNA, Plant/genetics
- Gene Dosage
- Gene Expression Regulation, Plant
- Genes, Plant/genetics
- Hordeum/genetics
- Molecular Sequence Data
- Phylogeny
- Plant Leaves/chemistry
- Plant Roots/chemistry
- RNA, Messenger/analysis
- RNA, Plant/chemistry
- Sequence Analysis, DNA
- Sequence Homology, Amino Acid
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Affiliation(s)
- T G Davies
- Biochemistry and Physiology Department, IACR-Rothamsted, Harpenden, Hertfordshire, UK.
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44
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Abstract
The Xenopus oocyte is a robust and convenient system for the transient expression of many different animal proteins and it has recently been demonstrated that oocytes can also translate, process, and target plant proteins. This expression system can also be used to clone genes, characterize function, and study posttranslational processing of proteins. Here we describe the methodology for the expression of plant proteins, in particular membrane proteins, in Xenopus oocytes.
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Affiliation(s)
- F L Theodoulou
- Biochemistry and Physiology Department, Rothamsted Experimental Station, Harpenden, Hertfordshire, England
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45
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Miller AJ, Smith SJ, Theodoulou FL. The heterologous expression of H(+)-coupled transporters in Xenopus oocytes. Symp Soc Exp Biol 1994; 48:167-177. [PMID: 7597641] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
The Xenopus oocyte has become a convenient and robust system for the expression of many different animal transport proteins and it has now been demonstrated that oocytes can also translate, process and target plant membrane proteins. Here we review the background to this expression system and discuss how it can be used to express plant transporters. A H+/hexose cotransporter (STP1) from Arabidopsis thaliana has been successfully expressed in oocytes and further characterization has shown the transporter to have properties similar to the same transporter expressed in yeast. However, the expression of H(+)-coupled transporters may present problems for oocyte intracellular pH regulation, because the influx of protons during their operation may acidify the cell. To investigate this possibility, proton-selective microelectrodes have been used to measure intracellular pH during symport of H+ and hexose in oocytes expressing STP1. These measurements showed that oocyte cytosolic pH is unaltered during H+/glucose cotransport, but is sensitive to changes in external pH.
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Affiliation(s)
- A J Miller
- Biochemistry and Physiology Department, Rothamsted Experimental Station, AFRC-IACR, Harpenden, Hertfordshire, UK
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