scholarly journals KEAP1–NRF2 signalling and autophagy in protection against oxidative and reductive proteotoxicity

2015 ◽  
Vol 469 (3) ◽  
pp. 347-355 ◽  
Author(s):  
Matthew Dodson ◽  
Matthew Redmann ◽  
Namakkal S. Rajasekaran ◽  
Victor Darley-Usmar ◽  
Jianhua Zhang
Keyword(s):  
Cell Signalling ◽  
Redox Status ◽  
Cellular Damage ◽  
Post Translational Modification ◽  
Redox Stress ◽  
Post Translational Modifications ◽  
Protein Thiols ◽  
Normal Metabolism ◽  
Thiol Redox ◽  
Cellular Pathogenesis

Maintaining cellular redox status to allow cell signalling to occur requires modulation of both the controlled production of oxidants and the thiol-reducing networks to allow specific regulatory post-translational modification of protein thiols. The oxidative stress hypothesis captured the concept that overproduction of oxidants can be proteotoxic, but failed to predict the recent finding that hyperactivation of the KEAP1–NRF2 system also leads to proteotoxicity. Furthermore, sustained activation of thiol redox networks by KEAP1–NRF2 induces a reductive stress, by decreasing the lifetime of necessary oxidative post-translational modifications required for normal metabolism or cell signalling. In this context, it is now becoming clear why antioxidants or hyperactivation of antioxidant pathways with electrophilic therapeutics can be deleterious. Furthermore, it suggests that the autophagy–lysosomal pathway is particularly important in protecting the cell against redox-stress-induced proteotoxicity, since it can degrade redox-damaged proteins without causing aberrant changes to the redox network needed for metabolism or signalling. In this context, it is important to understand: (i) how NRF2-mediated redox signalling, or (ii) the autophagy-mediated antioxidant/reductant pathways sense cellular damage in the context of cellular pathogenesis. Recent studies indicate that the modification of protein thiols plays an important role in the regulation of both the KEAP1–NRF2 and autophagy pathways. In the present review, we discuss evidence demonstrating that the KEAP1–NRF2 pathway and autophagy act in concert to combat the deleterious effects of proteotoxicity. These findings are discussed with a special emphasis on their impact on cardiovascular disease and neurodegeneration.

Modulation of the specific glutathionylation of mitochondrial proteins in the yeast Saccharomyces cerevisiae under basal and stress conditions

2017 ◽  
Vol 474 (7) ◽  
pp. 1175-1193 ◽  
Author(s):  
Rachel Gergondey ◽  
Camille Garcia ◽  
Christophe H. Marchand ◽  
Stephane D. Lemaire ◽  
Jean-Michel Camadro ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Saccharomyces Cerevisiae ◽  
Adaptive Response ◽  
Metabolic Response ◽  
Covalent Binding ◽  
Redox Status ◽  
Stress Conditions ◽  
Post Translational Modification ◽  
Yeast Saccharomyces Cerevisiae ◽  
Protein Thiols

The potential biological consequences of oxidative stress and changes in glutathione levels include the oxidation of susceptible protein thiols and reversible covalent binding of glutathione to the –SH groups of proteins by S-glutathionylation. Mitochondria are central to the response to oxidative stress and redox signaling. It is therefore crucial to explore the adaptive response to changes in thiol-dependent redox status in these organelles. We optimized the purification protocol of glutathionylated proteins in the yeast Saccharomyces cerevisiae and present a detailed proteomic analysis of the targets of protein glutathionylation in cells undergoing constitutive metabolism and after exposure to various stress conditions. This work establishes the physiological importance of the glutathionylation process in S. cerevisiae under basal conditions and provides evidence for an atypical and unexpected cellular distribution of the process between the cytosol and mitochondria. In addition, our data indicate that each oxidative condition (diamide, GSSG, H2O2, or the presence of iron) elicits an adaptive metabolic response affecting specific mitochondrial metabolic pathways, mainly involved in the energetic maintenance of the cells. The correlation of protein modifications with intracellular glutathione levels suggests that protein deglutathionylation may play a role in protecting mitochondria from oxidative stress. This work provides further insights into the diversity of proteins undergoing glutathionylation and the role of this post-translational modification as a regulatory process in the adaptive response of the cell.

scholarly journals Elamipretide (SS-31) Treatment Attenuates Age-Associated Post-Translational Modifications of Heart Proteins

2021 ◽  
Author(s):  
Jeremy A Whitson ◽  
Miguel Martin-Perez ◽  
Tong Zhang ◽  
Matthew J Gaffrey ◽  
Gennifer E Merrihew ◽  
...  
Keyword(s):  
Heart Function ◽  
Shotgun Proteomics ◽  
Mouse Heart ◽  
Post Translational Modifications ◽  
Functional Deficits ◽  
Age Related ◽  
Parallel Reaction Monitoring ◽  
Protein Thiols ◽  
Thiol Redox ◽  
Effects Of Aging

It has been demonstrated that elamipretide (SS-31) rescues age-related functional deficits in the heart but the full set of mechanisms behind this have yet to be determined. We investigated the hypothesis that elamipretide influences post-translational modifications to heart proteins. The S-glutathionylation and phosphorylation proteomes of mouse hearts were analyzed using shotgun proteomics to assess the effects of aging on these post-translational modifications and the ability of the mitochondria-targeted drug elamipretide to reverse age-related changes. Aging led to an increase in oxidation of protein thiols demonstrated by increased S-glutathionylation of cysteine residues on proteins from Old (24 months old at the start of the study) mouse hearts compared to Young (5-6 months old). This shift in the oxidation state of the proteome was almost completely reversed by 8-weeks of treatment with elamipretide. Many of the significant changes that occurred were in proteins involved in mitochondrial or cardiac function. We also found changes in the mouse heart phosphoproteome that were associated with age, some of which were partially restored with elamipretide treatment. Parallel reaction monitoring of a subset of phosphorylation sites revealed that the unmodified peptide reporting for Myot S231 increased with age, but not its phosphorylated form and that both phosphorylated and unphosphorylated forms of the peptide covering cMyBP-C S307 increased, but that elamipretide treatment did not affect these changes. These results suggest that changes to thiol redox state and phosphorylation status are two ways in which age may affect mouse heart function, which can be restored by treatment with elamipretide.

scholarly journals Protein Lipoxidation: Basic Concepts and Emerging Roles

Antioxidants ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 295
Author(s):  
Álvaro Viedma-Poyatos ◽  
Patricia González-Jiménez ◽  
Ophélie Langlois ◽  
Idoia Company-Marín ◽  
Corinne M. Spickett ◽  
...  
Keyword(s):  
Cell Signalling ◽  
Stress Protein ◽  
Cytoskeletal Proteins ◽  
Detailed Knowledge ◽  
Post Translational Modification ◽  
Complex Interplay ◽  
Protein Targets ◽  
Post Translational Modifications ◽  
Lipid Species ◽  
Functionally Diverse

Protein lipoxidation is a non-enzymatic post-translational modification that consists of the covalent addition of reactive lipid species to proteins. This occurs under basal conditions but increases in situations associated with oxidative stress. Protein targets for lipoxidation include metabolic and signalling enzymes, cytoskeletal proteins, and transcription factors, among others. There is strong evidence for the involvement of protein lipoxidation in disease, including atherosclerosis, neurodegeneration, and cancer. Nevertheless, the involvement of lipoxidation in cellular regulatory mechanisms is less understood. Here we review basic aspects of protein lipoxidation and discuss several features that could support its role in cell signalling, including its selectivity, reversibility, and possibilities for regulation at the levels of the generation and/or detoxification of reactive lipids. Moreover, given the great structural variety of electrophilic lipid species, protein lipoxidation can contribute to the generation of multiple structurally and functionally diverse protein species. Finally, the nature of the lipoxidised proteins and residues provides a frameshift for a complex interplay with other post-translational modifications, including redox and redox-regulated modifications, such as oxidative modifications and phosphorylation, thus strengthening the importance of detailed knowledge of this process.

scholarly journals Thiol Redox Transitions in Cell Signaling: a Lesson from N-Acetylcysteine

2010 ◽  
Vol 10 ◽  
pp. 1192-1202 ◽  
Author(s):  
Tiziana Parasassi ◽  
Roberto Brunelli ◽  
Graziella Costa ◽  
Marco De Spirito ◽  
Ewa Krasnowska ◽  
...  
Keyword(s):  
Gene Expression ◽  
Cell Signaling ◽  
Global Gene Expression ◽  
Redox Status ◽  
Post Translational Modification ◽  
Redox Switch ◽  
Redox Transitions ◽  
Thiol Redox ◽  
Redox Switches ◽  
External Stimuli

The functional status of cells is under the control of external stimuli affecting the function of critical proteins and eventually gene expression. Signal sensing and transduction by messengers to specific effectors operate by post-translational modification of proteins, among which thiol redox switches play a fundamental role that is just beginning to be understood. The maintenance of the redox status is, indeed, crucial for cellular homeostasis and its dysregulation towards a more oxidized intracellular environment is associated with aberrant proliferation, ultimately related to diseases such as cancer, cardiovascular disease, and diabetes. Redox transitions occur in sensitive cysteine residues of regulatory proteins relevant to signaling, their evolution to metastable disulfides accounting for the functional redox switch. N-acetylcysteine (NAC) is a thiol-containing compound that is able to interfere with redox transitions of thiols and, thus, in principle, able to modulate redox signaling. We here review the redox chemistry of NAC, then screen possible mechanisms to explain the effects observed in NAC-treated normal and cancer cells; such effects involve a modification of global gene expression, thus of functions and morphology, with a leitmotif of a switch from proliferation to terminal differentiation. The regulation of thiol redox transitions in cell signaling is, therefore, proposed as a new tool, holding promise not only for a deeper explanation of mechanisms, but indeed for innovative pharmacological interventions.

Dicarbonyl derived post-translational modifications: chemistry bridging biology and aging-related disease

2020 ◽  
Vol 64 (1) ◽  
pp. 97-110
Author(s):  
Christian Sibbersen ◽  
Mogens Johannsen
Keyword(s):  
Mass Spectrometry ◽  
Future Research ◽  
Amino Acid Residues ◽  
Post Translational Modification ◽  
Dicarbonyl Compounds ◽  
Protein Targets ◽  
Post Translational Modifications ◽  
Reactive Protein ◽  
Glycation End Products ◽  
Direct Mass Spectrometry

Abstract In living systems, nucleophilic amino acid residues are prone to non-enzymatic post-translational modification by electrophiles. α-Dicarbonyl compounds are a special type of electrophiles that can react irreversibly with lysine, arginine, and cysteine residues via complex mechanisms to form post-translational modifications known as advanced glycation end-products (AGEs). Glyoxal, methylglyoxal, and 3-deoxyglucosone are the major endogenous dicarbonyls, with methylglyoxal being the most well-studied. There are several routes that lead to the formation of dicarbonyl compounds, most originating from glucose and glucose metabolism, such as the non-enzymatic decomposition of glycolytic intermediates and fructosyl amines. Although dicarbonyls are removed continuously mainly via the glyoxalase system, several conditions lead to an increase in dicarbonyl concentration and thereby AGE formation. AGEs have been implicated in diabetes and aging-related diseases, and for this reason the elucidation of their structure as well as protein targets is of great interest. Though the dicarbonyls and reactive protein side chains are of relatively simple nature, the structures of the adducts as well as their mechanism of formation are not that trivial. Furthermore, detection of sites of modification can be demanding and current best practices rely on either direct mass spectrometry or various methods of enrichment based on antibodies or click chemistry followed by mass spectrometry. Future research into the structure of these adducts and protein targets of dicarbonyl compounds may improve the understanding of how the mechanisms of diabetes and aging-related physiological damage occur.

scholarly journals Immunological discrimination of β-tubulin isoforms in developing mouse brain. Post-translational modification of non-class-III β-tubulins

1992 ◽  
Vol 288 (3) ◽  
pp. 919-924 ◽  
Author(s):  
I Linhartová ◽  
P Dráber ◽  
E Dráberová ◽  
V Viklický
Keyword(s):  
Mouse Brain ◽  
Specific Class ◽  
Class Iii ◽  
Post Translational Modification ◽  
Beta Tubulin ◽  
Developmentally Regulated ◽  
Post Translational Modifications ◽  
Tubulin Isotypes ◽  
Tubulin Isoforms ◽  
Developing Mouse Brain

Individual beta-tubulin isoforms in developing mouse brain were characterized using immunoblotting, after preceding high-resolution isoelectric focusing, with monoclonal antibodies against different structural regions of beta-tubulin. Some of the antibodies reacted with a limited number of tubulin isoforms in all stages of brain development and in HeLa cells. The epitope for the TU-14 antibody was located in the isotype-defining domain and was present on the beta-tubulin isotypes of classes I, II and IV, but absent on the neuron-specific class-III isotype. The data suggest that non-class-III beta-tubulins in mouse brain are substrates for developmentally regulated post-translational modifications and that beta-tubulins of non-neuronal cells are also post-translationally modified.

scholarly journals Protocol for determining protein cysteine thiol redox status using western blot analysis

2021 ◽  
Vol 2 (2) ◽  
pp. 100566
Author(s):  
Bikram Datt Pant ◽  
Sunhee Oh ◽  
Kirankumar S. Mysore
Keyword(s):  
Western Blot ◽  
Blot Analysis ◽  
Western Blot Analysis ◽  
Redox Status ◽  
Thiol Redox

scholarly journals Post translational modifications of milk proteins in geographically diverse goat breeds

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
P. K. Rout ◽  
M. Verma
Keyword(s):  
Protein Function ◽  
Whey Proteins ◽  
Milk Proteins ◽  
Goat Milk ◽  
Peptide Sequence ◽  
Cow Milk ◽  
Post Translational Modification ◽  
Post Translational Modifications ◽  
Functional Roles ◽  
Dpp Iv

AbstractGoat milk is a source of nutrition in difficult areas and has lesser allerginicity than cow milk. It is leading in the area for nutraceutical formulation and drug development using goat mammary gland as a bioreactor. Post translational modifications of a protein regulate protein function, biological activity, stabilization and interactions. The protein variants of goat milk from 10 breeds were studied for the post translational modifications by combining highly sensitive 2DE and Q-Exactive LC-MS/MS. Here we observed high levels of post translational modifications in 201 peptides of 120 goat milk proteins. The phosphosites observed for CSN2, CSN1S1, CSN1S2, CSN3 were 11P, 13P, 17P and 6P, respectively in 105 casein phosphopeptides. Whey proteins BLG and LALBA showed 19 and 4 phosphosites respectively. Post translational modification was observed in 45 low abundant non-casein milk proteins mainly associated with signal transduction, immune system, developmental biology and metabolism pathways. Pasp is reported for the first time in 47 sites. The rare conserved peptide sequence of (SSSEE) was observed in αS1 and αS2 casein. The functional roles of identified phosphopeptides included anti-microbial, DPP-IV inhibitory, anti-inflammatory and ACE inhibitory. This is first report from tropics, investigating post translational modifications in casein and non-casein goat milk proteins and studies their interactions.

scholarly journals System-wide identification and prioritization of enzyme substrates by thermal analysis

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Amir Ata Saei ◽  
Christian M. Beusch ◽  
Pierre Sabatier ◽  
Juan Astorga Wells ◽  
Hassan Gharibi ◽  
...  
Keyword(s):  
Thermal Analysis ◽  
Thioredoxin Reductase ◽  
Structural Level ◽  
Post Translational Modification ◽  
Post Translational Modifications ◽  
Enzyme Substrate ◽  
Thioredoxin Reductase 1 ◽  
Enzyme Substrates ◽  
Substrate Proteins

AbstractDespite the immense importance of enzyme–substrate reactions, there is a lack of general and unbiased tools for identifying and prioritizing substrate proteins that are modified by the enzyme on the structural level. Here we describe a high-throughput unbiased proteomics method called System-wide Identification and prioritization of Enzyme Substrates by Thermal Analysis (SIESTA). The approach assumes that the enzymatic post-translational modification of substrate proteins is likely to change their thermal stability. In our proof-of-concept studies, SIESTA successfully identifies several known and novel substrate candidates for selenoprotein thioredoxin reductase 1, protein kinase B (AKT1) and poly-(ADP-ribose) polymerase-10 systems. Wider application of SIESTA can enhance our understanding of the role of enzymes in homeostasis and disease, opening opportunities to investigate the effect of post-translational modifications on signal transduction and facilitate drug discovery.

scholarly journals Role of Host-Mediated Post-Translational Modifications (PTMs) in RNA Virus Pathogenesis

2020 ◽  
Vol 22 (1) ◽  
pp. 323
Author(s):  
Ramesh Kumar ◽  
Divya Mehta ◽  
Nimisha Mishra ◽  
Debasis Nayak ◽  
Sujatha Sunil
Keyword(s):  
Rna Virus ◽  
Viral Proteins ◽  
Post Translational Modification ◽  
Host Proteins ◽  
Viral Protein Synthesis ◽  
Post Translational Modifications ◽  
Small Proteins ◽  
Cellular Machinery ◽  
Chemical Groups

Being opportunistic intracellular pathogens, viruses are dependent on the host for their replication. They hijack host cellular machinery for their replication and survival by targeting crucial cellular physiological pathways, including transcription, translation, immune pathways, and apoptosis. Immediately after translation, the host and viral proteins undergo a process called post-translational modification (PTM). PTMs of proteins involves the attachment of small proteins, carbohydrates/lipids, or chemical groups to the proteins and are crucial for the proteins’ functioning. During viral infection, host proteins utilize PTMs to control the virus replication, using strategies like activating immune response pathways, inhibiting viral protein synthesis, and ultimately eliminating the virus from the host. PTM of viral proteins increases solubility, enhances antigenicity and virulence properties. However, RNA viruses are devoid of enzymes capable of introducing PTMs to their proteins. Hence, they utilize the host PTM machinery to promote their survival. Proteins from viruses belonging to the family: Togaviridae, Flaviviridae, Retroviridae, and Coronaviridae such as chikungunya, dengue, zika, HIV, and coronavirus are a few that are well-known to be modified. This review discusses various host and virus-mediated PTMs that play a role in the outcome during the infection.

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