Thioredoxin-mediated regulation of (photo)respiration and central metabolism. (27th February 2021)

• Record Type: Journal Article
• Authors: da Fonseca-Pereira, Paula; Souza, Paulo V L; Fernie, Alisdair R; Timm, Stefan; Daloso, Danilo M; Araújo, Wagner L
• Editors: Lawson, Tracy
• Is Part Of: Journal of experimental botany. Volume 72:Number 17(2021)
• Page Start: 5987
• Page End: 6002
• Publication Date: 2021-02-27
• Subjects: Metabolic control -- metabolic regulation -- mitochondrial thioredoxins -- photorespiration -- redox metabolism -- TCA cycle; Botany -- Periodicals; Botany, Experimental -- Periodicals; Plant physiology -- Periodicals; 580
• DOI: 10.1093/jxb/erab098
• Languages: English
• ISSNs: 0022-0957

Abstract

Abstract : Recent evidence indicates that the thioredoxin (TRX) system regulates key enzymes of mitochondrial (photo)respiratory metabolism, extending the role of TRX-mediated metabolic regulation beyond the plastids. Abstract: Thioredoxins (TRXs) are ubiquitous proteins engaged in the redox regulation of plant metabolism. Whilst the light-dependent TRX-mediated activation of Calvin–Benson cycle enzymes is well documented, the role of extraplastidial TRXs in the control of the mitochondrial (photo)respiratory metabolism has been revealed relatively recently. Mitochondrially located TRX o1 has been identified as a regulator of alternative oxidase, enzymes of, or associated with, the tricarboxylic acid (TCA) cycle, and the mitochondrial dihydrolipoamide dehydrogenase (mtLPD) involved in photorespiration, the TCA cycle, and the degradation of branched chain amino acids. TRXs are seemingly a major point of metabolic regulation responsible for activating photosynthesis and adjusting mitochondrial photorespiratory metabolism according to the prevailing cellular redox status. Furthermore, TRX-mediated (de)activation of TCA cycle enzymes contributes to explain the non-cyclic flux mode of operation of this cycle in illuminated leaves. Here we provide an overview on the decisive role of TRXs in the coordination of mitochondrial metabolism in the light and provide in silico evidence for other redox-regulated photorespiratory enzymes. We further discuss the consequences of mtLPD regulation beyond photorespiration and provide outstanding questions that should be addressed in future studies to improve our understanding of the role of TRXs in the regulation of central metabolism.