scholarly journals Post-Translational Modifications of Nitrate Reductases Autoregulates Nitric Oxide Biosynthesis in Arabidopsis

2021 ◽  
Vol 22 (2) ◽  
pp. 549
Author(s):  
Álvaro Costa-Broseta ◽  
MariCruz Castillo ◽  
José León
Keyword(s):  
Nitric Oxide ◽  
Stress Responses ◽  
Feedback Loop ◽  
Nitrate Assimilation ◽  
Wild Type ◽  
Post Translational Modifications ◽  
Lysine Residues ◽  
Living Organisms ◽  
Regulatory Feedback Loop ◽  
Nitrate Reductases

Nitric oxide (NO) is a regulator of growth, development, and stress responses in living organisms. Plant nitrate reductases (NR) catalyze the reduction of nitrate to nitrite or, alternatively, to NO. In plants, NO action and its targets remain incompletely understood, and the way NO regulates its own homeostasis remains to be elucidated. A significant transcriptome overlapping between NO-deficient mutant and NO-treated wild type plants suggests that NO could negatively regulate its biosynthesis. A significant increase in NO content was detected in transgenic plants overexpressing NR1 and NR2 proteins. In turn, NR protein and activity as well as NO content, decreased in wild-type plants exposed to a pulse of NO gas. Tag-aided immunopurification procedures followed by tandem mass spectrometry allowed identifying NO-triggered post-translational modifications (PTMs) and ubiquitylation sites in NRs. Nitration of tyrosine residues and S-nitrosation of cysteine residues affected key amino acids involved in binding the essential FAD and molybdenum cofactors. NO-related PTMs were accompanied by ubiquitylation of lysine residues flanking the nitration and S-nitrosation sites. NO-induced PTMs of NRs potentially inhibit their activities and promote their proteasome-mediated degradation. This auto-regulatory feedback loop may control nitrate assimilation to ammonium and nitrite-derived production of NO under complex environmental conditions.

scholarly journals Nitrite and nitric oxide are important in the adjustment of primary metabolism during the hypersensitive response in tobacco

2019 ◽  
Vol 70 (17) ◽  
pp. 4571-4582 ◽  
Author(s):  
Luis A J Mur ◽  
Aprajita Kumari ◽  
Yariv Brotman ◽  
Jurgen Zeier ◽  
Julien Mandon ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Pseudomonas Syringae ◽  
Hypersensitive Response ◽  
Nitrate Assimilation ◽  
Pathogen Resistance ◽  
No Production ◽  
Primary Metabolism ◽  
Metabolomic Analysis ◽  
Wild Type ◽  
Sufficient Reduction

Abstract Nitrate and ammonia deferentially modulate primary metabolism during the hypersensitive response in tobacco. In this study, tobacco RNAi lines with low nitrite reductase (NiRr) levels were used to investigate the roles of nitrite and nitric oxide (NO) in this process. The lines accumulate NO2–, with increased NO generation, but allow sufficient reduction to NH4+ to maintain plant viability. For wild-type (WT) and NiRr plants grown with NO3–, inoculation with the non-host biotrophic pathogen Pseudomonas syringae pv. phaseolicola induced an accumulation of nitrite and NO, together with a hypersensitive response (HR) that resulted in decreased bacterial growth, increased electrolyte leakage, and enhanced pathogen resistance gene expression. These responses were greater with increases in NO or NO2– levels in NiRr plants than in the WT under NO3– nutrition. In contrast, WT and NiRr plants grown with NH4+ exhibited compromised resistance. A metabolomic analysis detected 141 metabolites whose abundance was differentially changed as a result of exposure to the pathogen and in response to accumulation of NO or NO2–. Of these, 13 were involved in primary metabolism and most were linked to amino acid and energy metabolism. HR-associated changes in metabolism that are often linked with primary nitrate assimilation may therefore be influenced by nitrite and NO production.

scholarly journals Human sirtuins are differentially sensitive to inhibition by nitrosating agents and other cysteine oxidants

2020 ◽  
Vol 295 (25) ◽  
pp. 8524-8536 ◽  
Author(s):  
Kelsey S. Kalous ◽  
Sarah L. Wynia-Smith ◽  
Steven B. Summers ◽  
Brian C. Smith
Keyword(s):  
Nitric Oxide ◽  
Hydrogen Peroxide ◽  
Comparative Study ◽  
Inflammatory Disease ◽  
Disease Development ◽  
Dependent Manner ◽  
Cysteine Modification ◽  
Chemical Probe ◽  
Post Translational Modifications ◽  
Lysine Residues

Sirtuins (e.g. human Sirt1–7) catalyze the removal of acyl groups from lysine residues in proteins in an NAD+-dependent manner, and loss of sirtuin deacylase activity correlates with the development of aging-related diseases. Although multiple reports suggest that sirtuin activity is regulated by oxidative post-translational modifications of cysteines during inflammation and aging, no systematic comparative study of potential direct sirtuin cysteine oxidative modifications has been performed. Here, using IC50 and kinact/KI analyses, we quantified the ability of nitrosothiols (S-nitrosoglutathione and S-nitroso-N-acetyl-d,l-penicillamine), nitric oxide, oxidized GSH, and hydrogen peroxide to post-translationally modify and inhibit the deacylase activity of Sirt1, Sirt2, Sirt3, Sirt5, and Sirt6. The inhibition was correlated with cysteine modification and assessed with chemical-probe and blot-based assays for cysteine S-nitrosation, sulfenylation, and glutathionylation. We show that the primarily nuclear sirtuins Sirt1 and Sirt6, as well as the primarily cytosolic sirtuin Sirt2, are modified and inhibited by cysteine S-nitrosation in response to exposure to both free nitric oxide and nitrosothiols (kinact/KI ≥ 5 m−1 s−1), which is the first report of Sirt2 and Sirt6 inhibition by S-nitrosation. Surprisingly, the mitochondrial sirtuins Sirt3 and Sirt5 were resistant to inhibition by cysteine oxidants. Collectively, these results suggest that nitric oxide–derived oxidants may causatively link nuclear and cytosolic sirtuin inhibition to aging-related inflammatory disease development.

scholarly journals A Regulatory Feedback Loop between RpoS and SpoT Supports the Survival of Legionella pneumophila in Water

2014 ◽  
Vol 81 (3) ◽  
pp. 918-928 ◽  
Author(s):  
Hana Trigui ◽  
Paulina Dudyk ◽  
Jinrok Oh ◽  
Jong-In Hong ◽  
Sebastien P. Faucher
Keyword(s):  
Legionella Pneumophila ◽  
Type Strain ◽  
Feedback Loop ◽  
Wild Type Strain ◽  
Disease Outbreaks ◽  
Stringent Response ◽  
Water Medium ◽  
Wild Type ◽  
Content Type ◽  
Regulatory Feedback Loop

ABSTRACTLegionella pneumophilais a waterborne pathogen, and survival in the aquatic environment is central to its transmission to humans. Therefore, identifying genes required for its survival in water could help prevent Legionnaires' disease outbreaks. In the present study, we investigate the role of the sigma factor RpoS in promoting survival in water, whereL. pneumophilaexperiences severe nutrient deprivation. TherpoSmutant showed a strong survival defect compared to the wild-type strain in defined water medium. The transcriptome of therpoSmutant during exposure to water revealed that RpoS represses genes associated with replication, translation, and transcription, suggesting that the mutant fails to shut down major metabolic programs. In addition, therpoSmutant is transcriptionally more active than the wild-type strain after water exposure. This could be explained by a misregulation of the stringent response in therpoSmutant. Indeed, therpoSmutant shows an increased expression ofspoTand a corresponding decrease in the level of (p)ppGpp, which is due to the presence of a negative feedback loop between RpoS and SpoT. Therefore, the lack of RpoS causes an aberrant regulation of the stringent response, which prevents the induction of a successful response to starvation.

scholarly journals RSK1 SUMOylation is required for KSHV lytic replication

2021 ◽  
Vol 17 (12) ◽  
pp. e1010123
Author(s):  
Zhenshan Liu ◽  
Chengrong Liu ◽  
Xin Wang ◽  
Wenwei Li ◽  
Jingfan Zhou ◽  
...  
Keyword(s):  
Kinase Activity ◽  
Mapk Pathway ◽  
Amino Acid Position ◽  
Lytic Replication ◽  
Wild Type ◽  
Post Translational Modifications ◽  
Cellular Processes ◽  
Phosphorylation Level ◽  
Lysine Residues ◽  
Substrate Phosphorylation

RSK1, a downstream kinase of the MAPK pathway, has been shown to regulate multiple cellular processes and is essential for lytic replication of a variety of viruses, including Kaposi’s sarcoma-associated herpesvirus (KSHV). Besides phosphorylation, it is not known whether other post-translational modifications play an important role in regulating RSK1 function. We demonstrate that RSK1 undergoes robust SUMOylation during KSHV lytic replication at lysine residues K110, K335, and K421. SUMO modification does not alter RSK1 activation and kinase activity upon KSHV ORF45 co-expression, but affects RSK1 downstream substrate phosphorylation. Compared to wild-type RSK1, the overall phosphorylation level of RxRxxS*/T* motif is significantly declined in RSK1K110/335/421R expressing cells. Specifically, SUMOylation deficient RSK1 cannot efficiently phosphorylate eIF4B. Sequence analysis showed that eIF4B has one SUMO-interacting motif (SIM) between the amino acid position 166 and 170 (166IRVDV170), which mediates the association between eIF4B and RSK1 through SUMO-SIM interaction. These results indicate that SUMOylation regulates the phosphorylation of RSK1 downstream substrates, which is required for efficient KSHV lytic replication.

Novel players fine-tune plant trade-offs

2015 ◽  
Vol 58 ◽  
pp. 83-100 ◽  
Author(s):  
Selena Gimenez-Ibanez ◽  
Marta Boter ◽  
Roberto Solano
Keyword(s):  
Ubiquitin Ligase ◽  
Feedback Loop ◽  
Molecular Level ◽  
26S Proteasome ◽  
Signalling Molecules ◽  
Transcriptional Reprogramming ◽  
Trade Offs ◽  
Jaz Proteins ◽  
Regulatory Feedback Loop ◽  
Fine Tune

Jasmonates (JAs) are essential signalling molecules that co-ordinate the plant response to biotic and abiotic challenges, as well as co-ordinating several developmental processes. Huge progress has been made over the last decade in understanding the components and mechanisms that govern JA perception and signalling. The bioactive form of the hormone, (+)-7-iso-jasmonyl-l-isoleucine (JA-Ile), is perceived by the COI1–JAZ co-receptor complex. JASMONATE ZIM DOMAIN (JAZ) proteins also act as direct repressors of transcriptional activators such as MYC2. In the emerging picture of JA-Ile perception and signalling, COI1 operates as an E3 ubiquitin ligase that upon binding of JA-Ile targets JAZ repressors for degradation by the 26S proteasome, thereby derepressing transcription factors such as MYC2, which in turn activate JA-Ile-dependent transcriptional reprogramming. It is noteworthy that MYCs and different spliced variants of the JAZ proteins are involved in a negative regulatory feedback loop, which suggests a model that rapidly turns the transcriptional JA-Ile responses on and off and thereby avoids a detrimental overactivation of the pathway. This chapter highlights the most recent advances in our understanding of JA-Ile signalling, focusing on the latest repertoire of new targets of JAZ proteins to control different sets of JA-Ile-mediated responses, novel mechanisms of negative regulation of JA-Ile signalling, and hormonal cross-talk at the molecular level that ultimately determines plant adaptability and survival.

scholarly journals InsP7is a small-molecule regulator of NUDT3-mediated mRNA decapping and processing-body dynamics

2020 ◽  
Vol 117 (32) ◽  
pp. 19245-19253 ◽  
Author(s):  
Soumyadip Sahu ◽  
Zhenzhen Wang ◽  
Xinfu Jiao ◽  
Chunfang Gu ◽  
Nikolaus Jork ◽  
...  
Keyword(s):  
Stress Responses ◽  
Messenger Rna ◽  
Control Process ◽  
Stem Cell Differentiation ◽  
Wild Type ◽  
Inositol Pyrophosphate ◽  
Body Dynamics ◽  
Processing Body ◽  
The Stability

Regulation of enzymatic 5′ decapping of messenger RNA (mRNA), which normally commits transcripts to their destruction, has the capacity to dynamically reshape the transcriptome. For example, protection from 5′ decapping promotes accumulation of mRNAs into processing (P) bodies—membraneless, biomolecular condensates. Such compartmentalization of mRNAs temporarily removes them from the translatable pool; these repressed transcripts are stabilized and stored until P-body dissolution permits transcript reentry into the cytosol. Here, we describe regulation of mRNA stability and P-body dynamics by the inositol pyrophosphate signaling molecule 5-InsP7(5-diphosphoinositol pentakisphosphate). First, we demonstrate 5-InsP7inhibits decapping by recombinant NUDT3 (Nudix [nucleoside diphosphate linked moiety X]-type hydrolase 3) in vitro. Next, in intact HEK293 and HCT116 cells, we monitored the stability of a cadre of NUDT3 mRNA substrates following CRISPR-Cas9 knockout ofPPIP5Ks(diphosphoinositol pentakisphosphate 5-kinases type 1 and 2, i.e.,PPIP5KKO), which elevates cellular 5-InsP7levels by two- to threefold (i.e., within the physiological rheostatic range). ThePPIP5KKO cells exhibited elevated levels of NUDT3 mRNA substrates and increased P-body abundance. Pharmacological and genetic attenuation of 5-InsP7synthesis in the KO background reverted both NUDT3 mRNA substrate levels and P-body counts to those of wild-type cells. Furthermore, liposomal delivery of a metabolically resistant 5-InsP7analog into wild-type cells elevated levels of NUDT3 mRNA substrates and raised P-body abundance. In the context that cellular 5-InsP7levels normally fluctuate in response to changes in the bioenergetic environment, regulation of mRNA structure by this inositol pyrophosphate represents an epitranscriptomic control process. The associated impact on P-body dynamics has relevance to regulation of stem cell differentiation, stress responses, and, potentially, amelioration of neurodegenerative diseases and aging.

scholarly journals PIAS1 potentiates the anti-EBV activity of SAMHD1 through SUMOylation

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Farjana Saiada ◽  
Kun Zhang ◽  
Renfeng Li
Keyword(s):  
Lytic Replication ◽  
Dependent Manner ◽  
Dna Viruses ◽  
Post Translational Modifications ◽  
Protein Protein Interaction ◽  
Barr Virus ◽  
Sumo Ligase ◽  
Lysine Residues ◽  
Epstein Barr ◽  
Rna And Dna

Abstract Background Sterile alpha motif and HD domain 1 (SAMHD1) is a deoxynucleotide triphosphohydrolase (dNTPase) that restricts the infection of a variety of RNA and DNA viruses, including herpesviruses. The anti-viral function of SAMHD1 is associated with its dNTPase activity, which is regulated by several post-translational modifications, including phosphorylation, acetylation and ubiquitination. Our recent studies also demonstrated that the E3 SUMO ligase PIAS1 functions as an Epstein-Barr virus (EBV) restriction factor. However, whether SAMHD1 is regulated by PIAS1 to restrict EBV replication remains unknown. Results In this study, we showed that PIAS1 interacts with SAMHD1 and promotes its SUMOylation. We identified three lysine residues (K469, K595 and K622) located on the surface of SAMHD1 as the major SUMOylation sites. We demonstrated that phosphorylated SAMHD1 can be SUMOylated by PIAS1 and SUMOylated SAMHD1 can also be phosphorylated by viral protein kinases. We showed that SUMOylation-deficient SAMHD1 loses its anti-EBV activity. Furthermore, we demonstrated that SAMHD1 is associated with EBV genome in a PIAS1-dependent manner. Conclusion Our study reveals that PIAS1 synergizes with SAMHD1 to inhibit EBV lytic replication through protein–protein interaction and SUMOylation.

scholarly journals Comprehensive Analysis of the Histone Deacetylase Gene Family in Chinese Cabbage (Brassica rapa): From Evolution and Expression Pattern to Functional Analysis of BraHDA3

Agriculture ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 244
Author(s):  
Seung Hee Eom ◽  
Tae Kyung Hyun
Keyword(s):  
Functional Analysis ◽  
Brassica Rapa ◽  
Chinese Cabbage ◽  
Stress Responses ◽  
Histone Deacetylases ◽  
Expression Patterns ◽  
Evolutionary Relationship ◽  
Gene Families ◽  
Physiological Processes ◽  
Lysine Residues

Histone deacetylases (HDACs) are known as erasers that remove acetyl groups from lysine residues in histones. Although plant HDACs play essential roles in physiological processes, including various stress responses, our knowledge concerning HDAC gene families and their evolutionary relationship remains limited. In Brassica rapa genome, we identified 20 HDAC genes, which are divided into three major groups: RPD3/HDA1, HD2, and SIR2 families. In addition, seven pairs of segmental duplicated paralogs and one pair of tandem duplicated paralogs were identified in the B. rapa HDAC (BraHDAC) family, indicating that segmental duplication is predominant for the expansion of the BraHDAC genes. The expression patterns of paralogous gene pairs suggest a divergence in the function of BraHDACs under various stress conditions. Furthermore, we suggested that BraHDA3 (homologous of Arabidopsis HDA14) encodes the functional HDAC enzyme, which can be inhibited by Class I/II HDAC inhibitor SAHA. As a first step toward understanding the epigenetic responses to environmental stresses in Chinese cabbage, our results provide a solid foundation for functional analysis of the BraHDAC family.

Neuregulin-1 Compensates for Endothelial Nitric Oxide Synthase Deficiency

2021 ◽  
Author(s):  
Hadis Shakeri ◽  
Jente R.A. Boen ◽  
Sofie De Moudt ◽  
Jhana O. Hendrickx ◽  
Arthur J.A. Leloup ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Cardiac Fibrosis ◽  
Separate Experiment ◽  
No Production ◽  
Ang Ii ◽  
Wild Type ◽  
Paracrine Factor ◽  
Renal Hypertrophy ◽  
Neuregulin 1 ◽  
Endothelial Nitric Oxide

Endothelial cells (ECs) secrete different paracrine signals that modulate the function of adjacent cells; two examples of these paracrine signals are nitric oxide (NO) and neuregulin-1 (NRG1), a cardioprotective growth factor. Currently, it is undetermined whether one paracrine factor can compensate for the loss of another. Herein, we hypothesized that NRG1 can compensate for endothelial NO synthase (eNOS) deficiency. Methods. We characterized eNOS null and wild type (WT) mice by cardiac ultrasound and histology and we determined circulating NRG1 levels. In a separate experiment, 8 groups of mice were divided into 4 groups of eNOS null mice and wild type (WT) mice; half of the mice received angiotensin II (Ang II) to induce a more severe phenotype. Mice were randomized to daily injections with NRG1 or vehicle for 28 days. Results. eNOS deficiency increased NRG1 plasma levels, indicating that ECs increase their NRG1 expression when NO production is deleted. eNOS deficiency also increased blood pressure, lowered heart rate, induced cardiac fibrosis, and affected diastolic function. In eNOS null mice, Ang II administration increased cardiac fibrosis, but also induced cardiac hypertrophy and renal fibrosis. NRG1 administration prevented the cardiac and renal hypertrophy and fibrosis caused by Ang II infusion and eNOS deficiency. Moreover, Nrg1 expression in the myocardium is shown to be regulated by miR-134. Conclusion. This study indicates that administration of endothelium-derived NRG1 can compensate for eNOS deficiency in the heart and kidneys.

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