scholarly journals Insights into the function of NADPH thioredoxin reductase C (NTRC) based on identification of NTRC-interacting proteins in vivo

2019 ◽  
Vol 70 (20) ◽  
pp. 5787-5798 ◽  
Author(s):  
Maricruz González ◽  
Víctor Delgado-Requerey ◽  
Julia Ferrández ◽  
Antonio Serna ◽  
Francisco Javier Cejudo
Keyword(s):  
Redox Regulation ◽  
Fluorescent Protein ◽  
Affinity Purification ◽  
Photosynthetic Apparatus ◽  
Thioredoxin Reductase ◽  
Redox System ◽  
Negative Control ◽  
Bimolecular Fluorescence Complementation ◽  
Redox Systems

Abstract Redox regulation in heterotrophic organisms relies on NADPH, thioredoxins (TRXs), and an NADPH-dependent TRX reductase (NTR). In contrast, chloroplasts harbor two redox systems, one that uses photoreduced ferredoxin (Fd), an Fd-dependent TRX reductase (FTR), and TRXs, which links redox regulation to light, and NTRC, which allows the use of NADPH for redox regulation. It has been shown that NTRC-dependent regulation of 2-Cys peroxiredoxin (PRX) is critical for optimal function of the photosynthetic apparatus. Thus, the objective of the present study was the analysis of the interaction of NTRC and 2-Cys PRX in vivo and the identification of proteins interacting with them with the aim of identifying chloroplast processes regulated by this redox system. To assess this objective, we generated Arabidopsis thaliana plants expressing either an NTRC–tandem affinity purification (TAP)-Tag or a green fluorescent protein (GFP)–TAP-Tag, which served as a negative control. The presence of 2-Cys PRX and NTRC in complexes isolated from NTRC–TAP-Tag-expressing plants confirmed the interaction of these proteins in vivo. The identification of proteins co-purified in these complexes by MS revealed the relevance of the NTRC–2-Cys PRX system in the redox regulation of multiple chloroplast processes. The interaction of NTRC with selected targets was confirmed in vivo by bimolecular fluorescence complementation (BiFC) assays.

scholarly journals The Lack of Mitochondrial Thioredoxin TRXo1 Affects In Vivo Alternative Oxidase Activity and Carbon Metabolism under Different Light Conditions

2019 ◽  
Vol 60 (11) ◽  
pp. 2369-2381 ◽  
Author(s):  
Igor Florez-Sarasa ◽  
Toshihiro Obata ◽  
N�stor Fern�ndez Del-Saz ◽  
Jean-Philippe Reichheld ◽  
Etienne H Meyer ◽  
...  
Keyword(s):  
Carbon Metabolism ◽  
Redox State ◽  
Redox Regulation ◽  
Alternative Oxidase ◽  
Tricarboxylic Acid Cycle ◽  
Reduced Form ◽  
Photosynthetic Parameters ◽  
Primary Metabolism ◽  
Redox Systems

Abstract The alternative oxidase (AOX) constitutes a nonphosphorylating pathway of electron transport in the mitochondrial respiratory chain that provides flexibility to energy and carbon primary metabolism. Its activity is regulated in vitro by the mitochondrial thioredoxin (TRX) system which reduces conserved cysteines residues of AOX. However, in vivo evidence for redox regulation of the AOX activity is still scarce. In the present study, the redox state, protein levels and in vivo activity of the AOX in parallel to photosynthetic parameters were determined in Arabidopsis knockout mutants lacking mitochondrial trxo1 under moderate (ML) and high light (HL) conditions, known to induce in vivo AOX activity. In addition, 13C- and 14C-labeling experiments together with metabolite profiling were performed to better understand the metabolic coordination between energy and carbon metabolism in the trxo1 mutants. Our results show that the in vivo AOX activity is higher in the trxo1 mutants at ML while the AOX redox state is apparently unaltered. These results suggest that mitochondrial thiol redox systems are responsible for maintaining AOX in its reduced form rather than regulating its activity in vivo. Moreover, the negative regulation of the tricarboxylic acid cycle by the TRX system is coordinated with the increased input of electrons into the AOX pathway. Under HL conditions, while AOX and photosynthesis displayed similar patterns in the mutants, photorespiration is restricted at the level of glycine decarboxylation most likely as a consequence of redox imbalance.

scholarly journals In Vivo Quantitative Estimation of DNA-Dependent Interaction of Sox2 and Oct4 Using BirA-Catalyzed Site-Specific Biotinylation

Biomolecules ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 142 ◽  
Author(s):  
Arman Kulyyassov ◽  
Vasily Ogryzko
Keyword(s):  
Transcription Factors ◽  
Protein Interactions ◽  
Fluorescent Protein ◽  
Quantitative Estimation ◽  
Multiple Reaction Monitoring ◽  
Negative Control ◽  
Protein Protein Interactions ◽  
Close Proximity ◽  
Green Fluorescent

Protein–protein interactions of core pluripotency transcription factors play an important role during cell reprogramming. Cell identity is controlled by a trio of transcription factors: Sox2, Oct4, and Nanog. Thus, methods that help to quantify protein–protein interactions may be useful for understanding the mechanisms of pluripotency at the molecular level. Here, a detailed protocol for the detection and quantitative analysis of in vivo protein–protein proximity of Sox2 and Oct4 using the proximity-utilizing biotinylation (PUB) method is described. The method is based on the coexpression of two proteins of interest fused to a biotin acceptor peptide (BAP)in one case and a biotin ligase enzyme (BirA) in the other. The proximity between the two proteins leads to more efficient biotinylation of the BAP, which can be either detected by Western blotting or quantified using proteomics approaches, such as a multiple reaction monitoring (MRM) analysis. Coexpression of the fusion proteins BAP-X and BirA-Y revealed strong biotinylation of the target proteins when X and Y were, alternatively, the pluripotency transcription factors Sox2 and Oct4, compared with the negative control where X or Y was green fluorescent protein (GFP), which strongly suggests that Sox2 and Oct4 come in close proximity to each other and interact.

Testicular injection of busulfan for recipient preparation in transplantation of spermatogonial stem cells in mice

2016 ◽  
Vol 28 (12) ◽  
pp. 1916 ◽  
Author(s):  
Yusheng Qin ◽  
Ling Liu ◽  
Yanan He ◽  
Wenzhi Ma ◽  
Huabin Zhu ◽  
...  
Keyword(s):  
Germ Cells ◽  
Fluorescent Protein ◽  
Positive Control ◽  
Negative Control ◽  
Seminiferous Tubules ◽  
Red Fluorescent Protein ◽  
Efferent Duct ◽  
Testicular Injection ◽  
Transplantation Recipient

Intraperitoneal busulfan injections are used to prepare recipients for spermatogonial stem cell (SSC) transplantation but they are associated with haematopoietic toxicity. Testicular injections of busulfan have been proposed to overcome this limitation. To date, testicular injections have not been studied in the mouse model. Therefore, in the present study we used ICR mice as recipients for SSC transplantation and prepared these mice by testicular injection of busulfan on both sides (2, 3, 4 or 6 mg kg–1 per side). Following this, donor germ cells expressing red fluorescent protein (RFP) from transgenic C57BL/6J male mice were transplanted into recipients via the efferent duct on Days 16–17 after busulfan treatment. Positive control mice were prepared by intraperitoneal injection of 40 mg kg–1 busulfan and negative control mice were treated with bilateral testicular injection of 50% dimethyl sulfoxide. On Day 49 after transplantation, recipient mice that were RFP-positive by in vivo imaging were mated with ICR female mice. Donor-derived germ cell colonies with red fluorescence were observed on Day 60 after transplantation, and donor-derived offspring were obtained. The results demonstrated that endogenous germ cells were successfully eliminated in the seminiferous tubules via testicular busulfan administration, and that exogenous SSCs successfully undergo spermatogenesis in the testes of recipient mice prepared by testicular injections of busulfan. In addition to its effects on recipient preparation, this method was safe in rodents and could possibly be adapted for use in other species.

In vivo associations of Escherichia coli NarJ with a peptide of the first 50 residues of nitrate reductase catalytic subunit NarG

2009 ◽  
Vol 55 (2) ◽  
pp. 179-188 ◽  
Author(s):  
Haiming Li ◽  
Raymond J. Turner
Keyword(s):  
Escherichia Coli ◽  
Nitrate Reductase ◽  
Fluorescent Protein ◽  
Yellow Fluorescent Protein ◽  
Catalytic Subunit ◽  
Bimolecular Fluorescence Complementation ◽  
E Coli ◽  
N Terminus ◽  
Tat System

The catalytic subunit of many Escherichia coli redox enzymes bares a twin-arginine translocation (Tat)-dependent signal peptide in its precursor, which directs the redox enzyme complex to this Sec-independent pathway. NarG of the E. coli nitrate reductase NarGHI complex possesses a vestige twin-arginine motif at its N terminus. During the cofactor insertion, and assembly and folding of the NarG–NarH complex, a chaperone protein, NarJ, is thought to interact with the N terminus and an unknown second site of NarG. Our previous in vitro study provided evidence that NarJ’s role shows some Tat system dependence. In this work, we investigated the associations of NarJ with a peptide of the first 50 residues of NarG (NarG50) in living cells. Two approaches were used: the Förster resonance energy transfer (FRET) based on yellow fluorescent protein – cyan fluorescent protein (YFP–CFP) and the bimolecular fluorescence complementation (BiFC). Compared with the wild-type (WT) E. coli cotransformants expressing both NarJ–YFP and NarG50–CFP, tat gene mutants gave an apparent FRET efficiency (Eapp) that was on the order of 25%–40% lower. These experiments implied a Tat system dependency of the in vivo associations between NarJ and the NarG50 peptide. In the BiFC assay, a 4-fold lower specific fluorescence intensity was observed for the E. coli WT cotransformants expressing both NarJ–Yc and NarG50–Yn than for its tat mutants, again suggesting a Tat dependence of the interactions. Fluorescence microscopy showed a “dot”/unipolar distribution of the reassembled YFP–NarJ:NarG50 both in WT and tat mutants, demonstrating a distinct localization of the interaction. Thus, although the degree of the interaction shows Tat dependence, the cell localization is less so. Taken together, these data further support that NarJ’s activity on NarG may be assisted by the Tat system.

scholarly journals The glutaredoxin mono- and di-thiol mechanisms for deglutathionylation are functionally equivalent: implications for redox systems biology

2015 ◽  
Vol 35 (1) ◽  
Author(s):  
Lefentse N. Mashamaite ◽  
Johann M. Rohwer ◽  
Ché S. Pillay
Keyword(s):  
Systems Biology ◽  
Active Site ◽  
Redox Regulation ◽  
Computational Models ◽  
Kinetic Modelling ◽  
Side Reaction ◽  
Kinetic Properties ◽  
Computational Systems Biology ◽  
Redox Systems

Glutathionylation plays a central role in cellular redox regulation and anti-oxidative defence. Grx (Glutaredoxins) are primarily responsible for reversing glutathionylation and their activity therefore affects a range of cellular processes, making them prime candidates for computational systems biology studies. However, two distinct kinetic mechanisms involving either one (monothiol) or both (dithiol) active-site cysteines have been proposed for their deglutathionylation activity and initial studies predicted that computational models based on either of these mechanisms will have different structural and kinetic properties. Further, a number of other discrepancies including the relative activity of active-site mutants and contrasting reciprocal plot kinetics have also been reported for these redoxins. Using kinetic modelling, we show that the dithiol and monothiol mechanisms are identical and, we were also able to explain much of the discrepant data found within the literature on Grx activity and kinetics. Moreover, our results have revealed how an apparently futile side-reaction in the monothiol mechanism may play a significant role in regulating Grx activity in vivo.

scholarly journals In vivo BiFC analysis of Y14 and NXF1 mRNA export complexes: preferential localization within and around SC35 domains

2006 ◽  
Vol 172 (3) ◽  
pp. 373-381 ◽  
Author(s):  
Ute Schmidt ◽  
Karsten Richter ◽  
Axel Bernhard Berger ◽  
Peter Lichter
Keyword(s):  
Nuclear Export ◽  
Fluorescent Protein ◽  
Specific Binding ◽  
Yellow Fluorescent Protein ◽  
Bimolecular Fluorescence Complementation ◽  
Nuclear Speckles ◽  
Mcf7 Cells ◽  
Permeabilized Cells ◽  
Preferential Localization

The bimolecular fluorescence complementation (BiFC) assay, which allows the investigation of interacting molecules in vivo, was applied to study complex formation between the splicing factor Y14 and nuclear export factor 1 (NXF1), which evidence indicates are functionally associated with nuclear mRNA. Y14 linked to the COOH terminus of yellow fluorescent protein (YFP; YC-Y14), and NXF1 fused to the NH2 terminus of YFP (YN-NXF1) expressed in MCF7 cells yielded BiFC upon specific binding. Fluorescence accumulated within and around nuclear speckles, suggesting the involvement of speckles in mRNA processing and export. Accordingly, BiFC depended on transcription and full-length NXF1. Coimmunoprecipitation of YC-Y14 with YN-NXF1, NXF1, Y14, and RNA indicated that YC-Y14 and YN-NXF1 functionally associate with RNA. Fluorescence recovery after photobleaching and fluorescence loss in photobleaching revealed that roughly half of the accumulated BiFC complexes were immobile in vivo. This immobile fraction was readily depleted by adenosine triphosphate (ATP) administration in permeabilized cells. These results suggest that a fraction of RNA, which remains in the nucleus for several hours despite its association with splicing and export proteins, accumulates in speckles because of an ATP-dependent mechanism.

Distinct electron transfer from ferredoxin–thioredoxin reductase to multiple thioredoxin isoforms in chloroplasts

2017 ◽  
Vol 474 (8) ◽  
pp. 1347-1360 ◽  
Author(s):  
Keisuke Yoshida ◽  
Toru Hisabori
Keyword(s):  
Electron Transfer ◽  
Redox Regulation ◽  
Thioredoxin Reductase ◽  
Reducing Power ◽  
Redox Potentials ◽  
Regulation Network ◽  
Electron Transfers ◽  
Kinetics Of

Thiol-based redox regulation is considered to support light-responsive control of various chloroplast functions. The redox cascade via ferredoxin–thioredoxin reductase (FTR)/thioredoxin (Trx) has been recognized as a key to transmitting reducing power; however, Arabidopsis thaliana genome sequencing has revealed that as many as five Trx subtypes encoded by a total of 10 nuclear genes are targeted to chloroplasts. Because each Trx isoform seems to have a distinct target selectivity, the electron distribution from FTR to multiple Trxs is thought to be the critical branch point for determining the consequence of chloroplast redox regulation. In the present study, we aimed to comprehensively characterize the kinetics of electron transfer from FTR to 10 Trx isoforms. We prepared the recombinant FTR protein from Arabidopsis in the heterodimeric form containing the Fe–S cluster. By reconstituting the FTR/Trx system in vitro, we showed that FTR prepared here was enzymatically active and suitable for uncovering biochemical features of chloroplast redox regulation. A series of redox state determinations using the thiol-modifying reagent, 4-acetamido-4′-maleimidylstilbene-2,2′-disulfonate, indicated that all chloroplast Trx isoforms are commonly reduced by FTR; however, significantly different efficiencies were evident. These differences were apparently correlated with the distinct midpoint redox potentials among Trxs. Even when the experiments were performed under conditions of hypothetical in vivo stoichiometry of FTR and Trxs, a similar trend in distinguishable electron transfers was observed. These data highlight an aspect of highly organized circuits in the chloroplast redox regulation network.

scholarly journals RNA Viruses vs. DNA Synthesis: A General Viral Strategy That May Contribute to the Protective Antiviral Effects of Selenium

2020 ◽  
Author(s):  
Ethan Will Taylor
Keyword(s):  
Dna Synthesis ◽  
Rna Synthesis ◽  
Rna Viruses ◽  
Thioredoxin Reductase ◽  
Selenium Deficiency ◽  
Redox System ◽  
Redox Systems ◽  
Dna Viruses ◽  
Antisense Knockdown ◽  
Hiv 1

The biosynthesis of DNA inherently competes with RNA synthesis because it depends on the reduction of ribonucleotides (RNA precursors) to 2’-deoxyribonucleotides by ribonucleotide reductase (RNR). Hence, RNA viruses can increase viral RNA production in cells by partially blocking the synthesis of DNA, e.g. by downregulating the mammalian selenoprotein thioredoxin reductase (TR), which normally acts to sustain DNA synthesis by regenerating reduced thioredoxin, a hydrogen donor for RNR. Computational and preliminary experimental evidence supports the hypothesis that a number of pathogenic RNA viruses, including HIV-1, Ebola, Zika, some flu viruses, and SARS-CoV-2, target TR isoforms by antisense. TR knockdown would create a host antioxidant defect that could be partially rectified by increased selenium intake, or be exacerbated by selenium deficiency, contributing to viral pathogenesis. There are several non-selenium-dependent means that viruses might also exploit to slow DNA synthesis, such as targeting RNR itself, or components of the glutaredoxin system, which serves as a backup redox system for RNR. HIV-1 substantially downregulates glutathione synthesis, so it interferes with both the thioredoxin and glutaredoxin systems. Computational results suggest that, like Ebola, SARS-CoV-2 targets TR3 by antisense. TR3 is the only TR isoform that includes an N-terminal glutaredoxin domain, so antisense knockdown of TR3 may also affect both redox systems, favoring RNA synthesis. In contrast, some DNA viruses encode their own glutaredoxins, thioredoxin-like proteins and even RNR homologues – so they are doing just the opposite, favoring DNA synthesis. This is clear evidence that viruses can benefit from shifting the RNA:DNA balance to their advantage.

scholarly journals A toolbox for efficient proximity-dependent biotinylation in zebrafish embryos

2021 ◽  
Author(s):  
Shimon M Rosenthal ◽  
Tvisha Misra ◽  
Hala Abdouni ◽  
Tess C Branon ◽  
Alice Y Ting ◽  
...  
Keyword(s):  
Cell Culture ◽  
Fluorescent Protein ◽  
Protein Complexes ◽  
Mammalian Cell Culture ◽  
Model Organism ◽  
Negative Control ◽  
Lamin A ◽  
Zebrafish Embryos ◽  
Time Resolved

Understanding how proteins are organized in compartments is essential to elucidating their function. While proximity-dependent approaches such as BioID have enabled a massive increase in information about organelles, protein complexes and other structures in cell culture, to date there have been only a few studies in living vertebrates. Here, we adapted proximity labeling for protein discovery in vivo in the vertebrate model organism, zebrafish. Using lamin A (LMNA) as bait and green fluorescent protein (GFP) as a negative control, we developed, optimized, and benchmarked in vivo TurboID and miniTurbo labeling in early zebrafish embryos. We developed both an mRNA injection protocol and a transgenic system in which transgene expression is controlled by a heat shock promoter. In both cases, biotin is provided directly in the egg water, and we demonstrate that 12 hours of labeling are sufficient for biotinylation of prey proteins, which should permit time-resolved analysis of development. After statistical scoring, we found that the proximal partners of LMNA detected in each system were enriched for nuclear envelope and nuclear membrane proteins, and included many orthologs of human proteins identified as proximity partners of lamin A in mammalian cell culture. The tools and protocols developed here will allow zebrafish researchers to complement genetic tools with powerful proteomics approaches.

scholarly journals NTRC-dependent redox balance of 2-Cys peroxiredoxins is needed for optimal function of the photosynthetic apparatus

2017 ◽  
Vol 114 (45) ◽  
pp. 12069-12074 ◽  
Author(s):  
Juan Manuel Pérez-Ruiz ◽  
Belén Naranjo ◽  
Valle Ojeda ◽  
Manuel Guinea ◽  
Francisco Javier Cejudo
Keyword(s):  
Redox Regulation ◽  
Photosynthetic Apparatus ◽  
Reducing Power ◽  
Redox Balance ◽  
Light Energy ◽  
Energy Utilization ◽  
Antioxidant Systems ◽  
Redox Systems ◽  
Triple Mutant ◽  
Low Efficiency

Thiol-dependent redox regulation allows the rapid adaptation of chloroplast function to unpredictable changes in light intensity. Traditionally, it has been considered that chloroplast redox regulation relies on photosynthetically reduced ferredoxin (Fd), thioredoxins (Trxs), and an Fd-dependent Trx reductase (FTR), the Fd-FTR-Trxs system, which links redox regulation to light. More recently, a plastid-localized NADPH-dependent Trx reductase (NTR) with a joint Trx domain, termed NTRC, was identified. NTRC efficiently reduces 2-Cys peroxiredoxins (Prxs), thus having antioxidant function, but also participates in redox regulation of metabolic pathways previously established to be regulated by Trxs. Thus, the NTRC, 2-Cys Prxs, and Fd-FTR-Trxs redox systems may act concertedly, but the nature of the relationship between them is unknown. Here we show that decreased levels of 2-Cys Prxs suppress the phenotype of the Arabidopsis thaliana ntrc KO mutant. The excess of oxidized 2-Cys Prxs in NTRC-deficient plants drains reducing power from chloroplast Trxs, which results in low efficiency of light energy utilization and impaired redox regulation of Calvin–Benson cycle enzymes. Moreover, the dramatic phenotype of the ntrc-trxf1f2 triple mutant, lacking NTRC and f-type Trxs, was also suppressed by decreased 2-Cys Prxs contents, as the ntrc-trxf1f2-Δ2cp mutant partially recovered the efficiency of light energy utilization and exhibited WT rate of CO2 fixation and growth phenotype. The suppressor phenotype was not caused by compensatory effects of additional chloroplast antioxidant systems. It is proposed that the Fd-FTR-Trx and NTRC redox systems are linked by the redox balance of 2-Cys Prxs, which is crucial for chloroplast function.

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