Protein Modification to Probe Intradynein Interactions and In Vivo Redox State

2007 ◽  
pp. 71-83 ◽  
Author(s):  
Ken-ichi Wakabayashi ◽  
Miho Sakato ◽  
Stephen M. King
Keyword(s):  
Protein Modification ◽  
Redox State

Protein Modification to Probe Intradynein Interactions and In Vivo Redox State

2007 ◽  
pp. 71-84
Author(s):  
Ken-ichi Wakabayashi ◽  
Miho Sakato ◽  
Stephen M. King
Keyword(s):  
Protein Modification ◽  
Redox State

In‐Vivo Two‐Photon Visualization and Quantitative Detection of Redox State of Cancer

2022 ◽  
Author(s):  
Wei Wang ◽  
Chenlu Wang ◽  
Guoming Liu ◽  
Long Jin ◽  
Zexi Lin ◽  
...  
Keyword(s):  
Redox State ◽  
Quantitative Detection ◽  
Two Photon

In vivo recording of epidermal stem cell redox state

2017 ◽  
Vol 108 ◽  
pp. S38
Author(s):  
Alexander Martin Wolf ◽  
Shigeo Ohta
Keyword(s):  
Stem Cell ◽  
Redox State ◽  
Epidermal Stem Cell

scholarly journals Resolving diurnal dynamics of the chloroplastic glutathione redox state in Arabidopsis reveals its photosynthetically-derived oxidation

2021 ◽  
Author(s):  
Zechariah Haber ◽  
Nardy Lampl ◽  
Andreas J Meyer ◽  
Einat Zelinger ◽  
Matanel Hipsch ◽  
...  
Keyword(s):  
Redox State ◽  
Fluorescent Protein ◽  
Operating Efficiency ◽  
High Temporal Resolution ◽  
Fluctuating Light ◽  
Gsh Metabolism ◽  
Glutathione Cycle ◽  
Green Fluorescent ◽  
Glutathione Redox

Abstract Plants are subjected to fluctuations in light intensity, and this causes unbalanced photosynthetic electron fluxes and overproduction of reactive oxygen species (ROS). Electrons needed for ROS detoxification are drawn, at least partially, from the cellular glutathione (GSH) pool via the ascorbate-glutathione cycle. Here, we explore the dynamics of the chloroplastic glutathione redox potential (chl-EGSH) using high-temporal-resolution monitoring of Arabidopsis (Arabidopsis thaliana) lines expressing the reduction-oxidation sensitive green fluorescent protein 2 (roGFP2in chloroplasts. This was carried out over several days, under dynamic environmental conditions and in correlation with PSII operating efficiency. Peaks in chl-EGSH oxidation during dark-to-light and light-to-dark transitions were observed. Increasing light intensities triggered a binary oxidation response, with a threshold around the light saturating point, suggesting two regulated oxidative states of the chl-EGSH. These patterns were not affected in npq1 plants, which are impaired in nonphotochemical quenching. Oscillations between the two oxidation states were observed under fluctuating light in WT and npq1 plants, but not in pgr5 plants, suggesting a role for PSI photoinhibition in regulating the chl-EGSH dynamics. Remarkably, pgr5 plants showed an increase in chl-EGSH oxidation during the nights following light stresses, linking daytime photoinhibition and nighttime GSH metabolism. This work provides a systematic view of the dynamics of the in vivo chloroplastic glutathione redox state during varying light conditions.

scholarly journals Selective inactivation of USP18 isopeptidase activity in vivo enhances ISG15 conjugation and viral resistance

2015 ◽  
Vol 112 (5) ◽  
pp. 1577-1582 ◽  
Author(s):  
Lars Ketscher ◽  
Ronny Hannß ◽  
David J. Morales ◽  
Anja Basters ◽  
Susana Guerra ◽  
...  
Keyword(s):  
Protease Activity ◽  
Protein Modification ◽  
Negative Regulator ◽  
Viral Resistance ◽  
Regulatory Function ◽  
Influenza B Virus ◽  
Influenza B ◽  
Minimal Risk ◽  
Independent Manner

Protein modification by the ubiquitin-like protein ISG15 is an interferon (IFN) effector system, which plays a major role in antiviral defense. ISG15 modification is counteracted by the isopeptidase USP18, a major negative regulator of IFN signaling, which was also shown to exert its regulatory function in an isopeptidase-independent manner. To dissect enzymatic and nonenzymatic functions of USP18 in vivo, we generated knock-in mice (USP18C61A/C61A) expressing enzymatically inactive USP18. USP18C61A/C61A mice displayed increased levels of ISG15 conjugates, validating that USP18 is a major ISG15 isopeptidase in vivo. Unlike USP18−/− mice, USP18C61A/C61A animals did not exhibit morphological abnormalities, fatal IFN hypersensitivity, or increased lethality, clearly showing that major USP18 functions are unrelated to its protease activity. Strikingly, elevated ISGylation in USP18C61A/C61A mice was accompanied by increased viral resistance against vaccinia virus and influenza B virus infections. Enhanced resistance upon influenza B infection in USP18C61A/C61A mice was completely reversed in USP18C61A/C61A mice, which additionally lack ISG15, providing evidence that the observed reduction in viral titers is ISG15 dependent. These results suggest that increasing ISGylation by specific inhibition of USP18 protease activity could constitute a promising antiviral strategy with only a minimal risk of severe adverse effects.

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 Molecular basis for t6A modification in human mitochondria

2020 ◽  
Vol 48 (6) ◽  
pp. 3181-3194 ◽  
Author(s):  
Jing-Bo Zhou ◽  
Yong Wang ◽  
Qi-Yu Zeng ◽  
Shi-Xin Meng ◽  
En-Duo Wang ◽  
...  
Keyword(s):  
Base Pair ◽  
Molecular Basis ◽  
Protein Modification ◽  
Trna Modification ◽  
Anticodon Loop ◽  
Recognition Mechanism ◽  
Trna Recognition ◽  
Translational Accuracy

Abstract N 6-Threonylcarbamoyladenosine (t6A) is a universal tRNA modification essential for translational accuracy and fidelity. In human mitochondria, YrdC synthesises an l-threonylcarbamoyl adenylate (TC-AMP) intermediate, and OSGEPL1 transfers the TC-moiety to five tRNAs, including human mitochondrial tRNAThr (hmtRNAThr). Mutation of hmtRNAs, YrdC and OSGEPL1, affecting efficient t6A modification, has been implicated in various human diseases. However, little is known about the tRNA recognition mechanism in t6A formation in human mitochondria. Herein, we showed that OSGEPL1 is a monomer and is unique in utilising C34 as an anti-determinant by studying the contributions of individual bases in the anticodon loop of hmtRNAThr to t6A modification. OSGEPL1 activity was greatly enhanced by introducing G38A in hmtRNAIle or the A28:U42 base pair in a chimeric tRNA containing the anticodon stem of hmtRNASer(AGY), suggesting that sequences of specific hmtRNAs are fine-tuned for different modification levels. Moreover, using purified OSGEPL1, we identified multiple acetylation sites, and OSGEPL1 activity was readily affected by acetylation via multiple mechanisms in vitro and in vivo. Collectively, we systematically elucidated the nucleotide requirement in the anticodon loop of hmtRNAs, and revealed mechanisms involving tRNA sequence optimisation and post-translational protein modification that determine t6A modification levels.

Two-dimensional analysis of the redox state of the rat cerebral cortex in vivo by NADH fluorescence photography

1977 ◽  
Vol 119 (2) ◽  
pp. 357-373 ◽  
Author(s):  
Sungchul Ji ◽  
Britton Chance ◽  
Bradley H. Stuart ◽  
Robert Nathan
Keyword(s):  
Cerebral Cortex ◽  
Dimensional Analysis ◽  
Redox State ◽  
Rat Cerebral Cortex ◽  
Two Dimensional ◽  
Nadh Fluorescence
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