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https://locus.ufv.br//handle/123456789/19445
Tipo: | Artigo |
Título: | Thioredoxin, a master regulator of the tricarboxylic acid cycle in plant mitochondria |
Autor(es): | Daloso, Danilo M. Müller, Karolin Obata, Toshihiro Florian, Alexandra Tohge, Takayuki Bottcher, Alexandra Riondet, Christophe Bariat, Laetitia Carrari, Fernando Nunes-Nesi, Adriano Buchanan, Bob B. Reichheld, Jean-Philippe Araújo, Wagner L. Fernie, Alisdair R. |
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 enzymeencoding 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. |
Palavras-chave: | Arabidopsis Redox regulation Thioredoxin TCA cycle regulation Citric acid cycle regulation |
Editor: | Proceedings of the National Academy of Sciences of the United States of America |
Tipo de Acesso: | National Academy of Sciences |
URI: | https://doi.org/10.1073/pnas.1424840112 http://www.locus.ufv.br/handle/123456789/19445 |
Data do documento: | 2-Fev-2015 |
Aparece nas coleções: | Artigos |
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Arquivo | Descrição | Tamanho | Formato | |
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artigo.pdf Until 2100-12-31 | Texto completo | 878,59 kB | Adobe PDF | Visualizar/Abrir ACESSO RESTRITO |
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