Thioredoxins （TRX） are key components of cellular redox balance, regulating many target proteins through thiol/disulfide exchange reactions. In higher plants, TRX constitute a complex multigenic family whose members...Thioredoxins （TRX） are key components of cellular redox balance, regulating many target proteins through thiol/disulfide exchange reactions. In higher plants, TRX constitute a complex multigenic family whose members have been found in almost all cellular compartments. Although chloroplastic and cytosolic TRX systems have been largely studied, the presence of a nuclear TRX system has been elusive for a long time. Nucleoredoxins （NRX） are potential nuclear TRX found in most eukaryotic organisms. In contrast to mammals, which harbor a unique NRX, angiosperms gen- erally possess multiple NRX organized in three subfamilies. Here, we show thatArabidopsis thaliana has two NRXgenes （AtNRX1 and AtNRX2）, respectively, belonging to subgroups I and III. While NRX1 harbors typical TRX active sites （WCG/ PPC）, NRX2 has atypical active sites （WCRPC and WCPPF）. Nevertheless, both NRXl and NRX2 have disulfide reduction capacities, although NRX1 alone can be reduced by the thioredoxin reductase NTRA. We also show that both NRX1 and NRX2 have a dual nuclear/cytosolic localization. Interestingly, we found that NTRA, previously identified as a cytosolic protein, is also partially localized in the nucleus, suggesting that a complete TRX system is functional in the nucleus. We show that NRX1 is mainly found as a dimer in vivo. nrxl and nrx2 knockout mutant plants exhibit no phenotypic perturbations under standard growth conditions. However, the nrxl mutant shows a reduced pollen fertility phenotype, suggesting a specific role of NRX1 at the haploid phase.展开更多
Osmotic stress caused by drought or high salt concentrations is a major threat that limits plant development and affect crop productivity.In the context of climate change,understanding the mechanisms by which plants p...Osmotic stress caused by drought or high salt concentrations is a major threat that limits plant development and affect crop productivity.In the context of climate change,understanding the mechanisms by which plants perceive their environment to adapt to their development is a major question.A common feature of plants being exposed to osmotic stress is the accumulation of excessive reactive oxygen species(ROS)(Martinière et al.,2019).ROS can oxidatively damage biological molecules,such as nucleic acids,proteins,and lipids,but also play important signaling functions.To protect from ROS-induced oxidation,living organisms have developed a large panel of enzymatic and non-enzymatic systems to remove ROS and oxidized molecules.展开更多
文摘Thioredoxins （TRX） are key components of cellular redox balance, regulating many target proteins through thiol/disulfide exchange reactions. In higher plants, TRX constitute a complex multigenic family whose members have been found in almost all cellular compartments. Although chloroplastic and cytosolic TRX systems have been largely studied, the presence of a nuclear TRX system has been elusive for a long time. Nucleoredoxins （NRX） are potential nuclear TRX found in most eukaryotic organisms. In contrast to mammals, which harbor a unique NRX, angiosperms gen- erally possess multiple NRX organized in three subfamilies. Here, we show thatArabidopsis thaliana has two NRXgenes （AtNRX1 and AtNRX2）, respectively, belonging to subgroups I and III. While NRX1 harbors typical TRX active sites （WCG/ PPC）, NRX2 has atypical active sites （WCRPC and WCPPF）. Nevertheless, both NRXl and NRX2 have disulfide reduction capacities, although NRX1 alone can be reduced by the thioredoxin reductase NTRA. We also show that both NRX1 and NRX2 have a dual nuclear/cytosolic localization. Interestingly, we found that NTRA, previously identified as a cytosolic protein, is also partially localized in the nucleus, suggesting that a complete TRX system is functional in the nucleus. We show that NRX1 is mainly found as a dimer in vivo. nrxl and nrx2 knockout mutant plants exhibit no phenotypic perturbations under standard growth conditions. However, the nrxl mutant shows a reduced pollen fertility phenotype, suggesting a specific role of NRX1 at the haploid phase.
基金supported by the Center National de la Recherche Scientifiqueby the University of Perpignan Via Domitia,and by the Agence Nationale de la Recherche(ANR-RE-PHARE19-CE12-0027 and ANR-RoxRNase20-CE12-0025-01).
文摘Osmotic stress caused by drought or high salt concentrations is a major threat that limits plant development and affect crop productivity.In the context of climate change,understanding the mechanisms by which plants perceive their environment to adapt to their development is a major question.A common feature of plants being exposed to osmotic stress is the accumulation of excessive reactive oxygen species(ROS)(Martinière et al.,2019).ROS can oxidatively damage biological molecules,such as nucleic acids,proteins,and lipids,but also play important signaling functions.To protect from ROS-induced oxidation,living organisms have developed a large panel of enzymatic and non-enzymatic systems to remove ROS and oxidized molecules.
