title: Thioredoxin, a master regulator of the tricarboxylic acid cycle in plant mitochondria.
abstract: Plant mitochondria have a fully operational tricarboxylic acid (TCA) cycle that plays a central role in generating ATP and providing carbon skeletons for a range of biosynthetic processes in both heterotrophic and photosynthetic tissues. The cycle enzyme-encoding genes have been well characterized in terms of transcriptional and effector-mediated regulation and have also been subjected to reverse genetic analysis. However, despite this wealth of attention, a central question remains unanswered: "What regulates flux through this pathway in vivo?" Previous proteomic experiments with Arabidopsis discussed below have revealed that a number of mitochondrial enzymes, including members of the TCA cycle and affiliated pathways, harbor thioredoxin (TRX)-binding sites and are potentially redox-regulated. We have followed up on this possibility and found TRX to be a redox-sensitive mediator of TCA cycle flux. In this investigation, we first characterized, at the enzyme and metabolite levels, mutants of the mitochondrial TRX pathway in Arabidopsis: the NADP-TRX reductase a and b double mutant (ntra ntrb) and the mitochondrially located thioredoxin o1 (trxo1) mutant. These studies were followed by a comparative evaluation of the redistribution of isotopes when (13)C-glucose, (13)C-malate, or (13)C-pyruvate was provided as a substrate to leaves of mutant or WT plants. In a complementary approach, we evaluated the in vitro activities of a range of TCA cycle and associated enzymes under varying redox states. The combined dataset suggests that TRX may deactivate both mitochondrial succinate dehydrogenase and fumarase and activate the cytosolic ATP-citrate lyase in vivo, acting as a direct regulator of carbon flow through the TCA cycle and providing a mechanism for the coordination of cellular function.
authors: Max-Planck-Institut für Molekulare Pflanzenphysiologie,14476 Potsdam-Golm, Germany; Max Planck Partner Group at the Departamento de Biologia Vegetal, Universidade Federal de Viçosa, 36570-900 Viçosa, MG, Brazil;
authors: Danilo M
authors: DM
authors: Daloso
authors: Max-Planck-Institut für Molekulare Pflanzenphysiologie,14476 Potsdam-Golm, Germany;
authors: Karolin
authors: K
authors: Müller
authors: Max-Planck-Institut für Molekulare Pflanzenphysiologie,14476 Potsdam-Golm, Germany;
authors: Toshihiro
authors: T
authors: Obata
authors: Max-Planck-Institut für Molekulare Pflanzenphysiologie,14476 Potsdam-Golm, Germany;
authors: Alexandra
authors: A
authors: Florian
authors: Max-Planck-Institut für Molekulare Pflanzenphysiologie,14476 Potsdam-Golm, Germany;
authors: Takayuki
authors: T
authors: Tohge
authors: Max-Planck-Institut für Molekulare Pflanzenphysiologie,14476 Potsdam-Golm, Germany;
authors: Alexandra
authors: A
authors: Bottcher
authors: Laboratoire Génome et Développement des Plantes, Unité Mixte de Recherche 5096, Centre National de la Recherche Scientifique, Université de Perpignan Via Domitia, 66860 Perpignan, France;
authors: Christophe
authors: C
authors: Riondet
authors: Laboratoire Génome et Développement des Plantes, Unité Mixte de Recherche 5096, Centre National de la Recherche Scientifique, Université de Perpignan Via Domitia, 66860 Perpignan, France;
authors: Laetitia
authors: L
authors: Bariat
authors: Instituto de Biotecnología, Instituto Nacional de Tecnología Agrícola, Consejo Nacional de Investigaciones Científicas y Técnicas, B1712WAA Castelar, Argentina; and.
authors: Fernando
authors: F
authors: Carrari
authors: Max Planck Partner Group at the Departamento de Biologia Vegetal, Universidade Federal de Viçosa, 36570-900 Viçosa, MG, Brazil;
authors: Adriano
authors: A
authors: Nunes-Nesi
authors: Department of Plant and Microbial Biology, University of California, Berkeley, CA 94720 view@berkeley.edu jpr@univ-perp.fr wlaraujo@ufv.br fernie@mpimp-golm.mpg.de.
authors: Bob B
authors: BB
authors: Buchanan
authors: Laboratoire Génome et Développement des Plantes, Unité Mixte de Recherche 5096, Centre National de la Recherche Scientifique, Université de Perpignan Via Domitia, 66860 Perpignan, France; view@berkeley.edu jpr@univ-perp.fr wlaraujo@ufv.br fernie@mpimp-golm.mpg.de.
authors: Jean-Philippe
authors: JP
authors: Reichheld
authors: Max Planck Partner Group at the Departamento de Biologia Vegetal, Universidade Federal de Viçosa, 36570-900 Viçosa, MG, Brazil; view@berkeley.edu jpr@univ-perp.fr wlaraujo@ufv.br fernie@mpimp-golm.mpg.de.
authors: Wagner L
authors: WL
authors: Araújo
authors: Max-Planck-Institut für Molekulare Pflanzenphysiologie,14476 Potsdam-Golm, Germany; view@berkeley.edu jpr@univ-perp.fr wlaraujo@ufv.br fernie@mpimp-golm.mpg.de.
authors: Alisdair R
authors: AR
authors: Fernie
mesh_terms: D017360:Arabidopsis / Q000235:genetics / Q000378:metabolism; D002247:Carbon Isotopes; D002951:Citrates / Q000378:metabolism; D002952:Citric Acid Cycle; D017343:Genes, Plant; D005816:Genetic Complementation Test; D055432:Metabolomics; D008928:Mitochondria / Q000378:metabolism*; D008954:Models, Biological; D009154:Mutation / Q000235:genetics; D018515:Plant Leaves / Q000201:enzymology; D018517:Plant Roots / Q000235:genetics / Q000378:metabolism; D018087:Plastids / Q000378:metabolism; D015203:Reproducibility of Results; D012639:Seeds / Q000254:growth & development / Q000378:metabolism; D013879:Thioredoxins / Q000378:metabolism*
chemical_list: D002247:Carbon Isotopes; D002951:Citrates; D013879:Thioredoxins
keywords: ATP-citrate lyase; Arabidopsis; citric acid cycle regulation; redox regulation; thioredoxin TCA cycle regulation
references: Phytochemistry. 2011 Jul;72(10):1081-91
references: 21146842
references: Science. 2003 Aug 1;301(5633):653-7
references: 12893945
references: Plant Cell Environ. 2012 Feb;35(2):202-16
references: 21410714
references: Plant Physiol. 2010 Jun;153(2):611-21
references: 20118274
references: Biochem J. 1937 Apr;31(4):645-60
references: 16746382
references: PLoS One. 2012;7(8):e42809
references: 22912743
references: J Exp Bot. 2002 Apr;53(370):773-87
references: 11912221
references: New Phytol. 2011 Jan;189(1):148-59
references: 20946418
references: Annu Rev Plant Physiol Plant Mol Biol. 2001 Jun;52:561-591
references: 11337409
references: Plant Physiol. 2009 Oct;151(2):603-19
references: 19675153
references: Proteomics. 2007 Nov;7(22):4158-70
references: 17994621
references: Front Plant Sci. 2014 Jun 10;5:266
references: 24959171
references: Trends Plant Sci. 2010 Aug;15(8):462-70
references: 20554469
references: Arabidopsis Book. 2011;9:e0142
references: 22303267
references: Plant Cell. 2005 Jan;17(1):182-203
references: 15608338
references: Trends Plant Sci. 2007 Mar;12(3):125-34
references: 17293156
references: Proc Natl Acad Sci U S A. 2004 Feb 24;101(8):2642-7
references: 14983062
references: J Exp Bot. 2005 Jun;56(416):1481-9
references: 15851411
references: Science. 2011 Dec 16;334(6062):1551-3
references: 22174252
references: Arch Biochem Biophys. 1991 May 15;287(1):195-8
references: 1897989
references: Plant Cell. 2008 Oct;20(10):2848-59
references: 18952776
references: Mol Plant. 2009 Mar;2(2):249-58
references: 19825611
references: J Biol Chem. 1972 Feb 10;247(3):667-79
references: 4333508
references: FEBS Lett. 2005 Jan 17;579(2):337-42
references: 15642341
references: J Bacteriol. 1975 Apr;122(1):224-34
references: 804468
references: Curr Opin Plant Biol. 2012 Jun;15(3):308-14
references: 22244081
references: J Biol Chem. 2007 Nov 9;282(45):32640-54
references: 17848555
references: J Biol Chem. 2013 Mar 22;288(12):8365-79
references: 23335511
references: Plant Physiol. 2006 Jun;141(2):412-22
references: 16648214
references: Plant Cell. 2013 Feb;25(2):694-714
references: 23444331
references: Proc Natl Acad Sci U S A. 2004 Oct 5;101(40):14545-50
references: 15385674
references: Trends Plant Sci. 2011 Sep;16(9):489-98
references: 21684795
references: Plant Cell. 2007 Jun;19(6):1851-65
references: 17586656
references: Biochem J. 1991 Jun 15;276 ( Pt 3):643-8
references: 1648348
references: Annu Rev Plant Biol. 2011;62:79-104
references: 21332361
references: Plant J. 2004 Aug;39(4):668-79
references: 15272882
references: Plant Physiol. 2011 Jan;155(1):2-18
references: 21205630
references: J Exp Bot. 2012 Apr;63(7):2705-16
references: 22268146
references: Proc Natl Acad Sci U S A. 2001 Nov 20;98(24):14144-9
references: 11717467
references: Plant J. 2014 Feb;77(3):367-79
references: 24274116
references: Plant Physiol. 2010 Mar;152(3):1501-13
references: 20089769
references: Biochim Biophys Acta. 2003 Sep 30;1606(1-3):117-25
references: 14507432
references: Proc Natl Acad Sci U S A. 2013 Feb 19;110(8):3185-90
references: 23382251
references: Mol Plant. 2014 Jan;7(1):156-69
references: 24198232
references: Proc Natl Acad Sci U S A. 2008 Jan 15;105(2):797-802
references: 18184808
references: Mol Plant. 2010 Nov;3(6):973-96
references: 20926550
references: Mol Plant. 2009 Mar;2(2):336-43
references: 19825618
references: Plant Cell Physiol. 2013 Jun;54(6):875-92
references: 23444301
references: Plant Cell. 2010 May;22(5):1549-63
references: 20501910
references: Trends Plant Sci. 2010 Sep;15(9):515-21
references: 20688558
references: Curr Opin Plant Biol. 2013 Jun;16(3):335-43
references: 23462640
references: Mitochondrion. 2008 Jan;8(1):47-60
references: 18033742
references: Proc Natl Acad Sci U S A. 2009 Jun 16;106(24):9908-13
references: 19470473
references: Trends Plant Sci. 2003 Nov;8(11):546-53
references: 14607100
references: Nat Protoc. 2006;1(1):387-96
references: 17406261
references: Plant Cell Environ. 2012 Jan;35(1):1-21
references: 21477125
references: Proc Natl Acad Sci U S A. 2010 Feb 23;107(8):3900-5
references: 20133584
references: Plant Physiol. 2007 Nov;145(3):626-39
references: 17885090
references: Proc Natl Acad Sci U S A. 2006 May 23;103(21):8287-92
references: 16698923
references: Antioxid Redox Signal. 2005 Jul-Aug;7(7-8):919-29
references: 15998247
references: Plant J. 2014 Jul;79(2):270-84
references: 24844815
references: Trends Plant Sci. 2010 Jun;15(6):330-6
references: 20403720
references: Nat Protoc. 2010 Jun;5(6):1210-27
references: 20539294
references: Proc Natl Acad Sci U S A. 2002 Dec 10;99(25):16325-30
references: 12456891
references: Proc Natl Acad Sci U S A. 2004 May 11;101(19):7475-80
references: 15123830
references: Plant Physiol. 2011 Sep;157(1):386-404
references: 21775496