Ulva prolifera,the primary causative species of green tide,has garnered significant attention due to its robust growth and reproductive capacity under high salt stress.However,there has been relatively little research...Ulva prolifera,the primary causative species of green tide,has garnered significant attention due to its robust growth and reproductive capacity under high salt stress.However,there has been relatively little research on the regulation of high salt stress in this species.In this study,we observed that high salt stress suppressed the growth of U.prolifera and leading to the nitric oxide(NO)accumulation,along with increased gene expression levels and enzyme activity of S-nitrosoglutathione reductase(GSNOR).Treatment with GSNOR inhibitor resulted in elevated NO levels under high salt stress,accompanied by reduced activity of antioxidant enzymes and decreased glutathione(GSH)accumulation,making U.prolifera more sensitive to high salt stress.Conversely,NO scavenger treatment not only reduced NO levels,but also weakened the high salt stress tolerance of U.prolifera.Furthermore,using tandem mass tags(TMT)switch analysis and mass spectrometry,we observed a significant increase in S nitrosylated protein levels in U.prolifera under high salt stress,with further augmentation upon GSNOR inhibitor treatment.We also found high salt stress induced S-nitrosylation(SNO)of glutathione reductase(GR),which is negatively regulated by GSNOR,resulting in increased GR activity.Our results show that under short-term high salt stress,the elevated expression level of GSNOR avoided excessive accumulation of NO,and a certain amount of NO enhanced the activity of antioxidant enzymes through SNO modification,which improve the high salt stress tolerance of U.prolifera,whereas under long-term high salt stress,excessive NO was toxic to U.prolifera.展开更多
The phytohormone auxin plays crucial roles in nearly every aspect of plant growth and development.Auxin signaling is activated through the phytohormone-induced proteasomal degradation of the Auxin/INDOLE-3-ACETIC ACID...The phytohormone auxin plays crucial roles in nearly every aspect of plant growth and development.Auxin signaling is activated through the phytohormone-induced proteasomal degradation of the Auxin/INDOLE-3-ACETIC ACID(Aux/IAA)family of transcriptional repressors.Notably,many auxin-modulated physiological processes are also regulated by nitric oxide(NO)that executes its biological effects predominantly through protein S-nitrosylation at specific cysteine residues.However,little is known about the molecular mechanisms in regulating the interactive NO and auxin networks.Here,we show that NO represses auxin signaling by inhibiting IAA17 protein degradation.NO induces the S-nitrosylation of Cys-70 located in the intrinsically disordered region of IAA17,which inhibits the TIR1-IAA17 interaction and consequently the proteasomal degradation of IAA17.The accumulation of a higher level of IAA17 attenuates auxin response.Moreover,an IAA17^(C70W)nitrosomimetic mutation renders the accumulation of a higher level of the mutated protein,thereby causing partial resistance to auxin and defective lateral root development.Taken together,these results suggest that S-nitrosylation of IAA17 at Cys-70 inhibits its interaction with TIR1,thereby negatively regulating auxin signaling.This study provides unique molecular insights into the redox-based auxin signaling in regulating plant growth and development.展开更多
A peptide hormone, ghrelin, recognized for its role in the regulation of nitric oxide production has emerged as an important modulator of oral mucosal inflammatory responses to periodontopathic bacterium, P. gingivali...A peptide hormone, ghrelin, recognized for its role in the regulation of nitric oxide production has emerged as an important modulator of oral mucosal inflammatory responses to periodontopathic bacterium, P. gingivalis. As cSrc kinase plays a major role in controlling the activity of nitric oxide synthase (NOS) system, in this study we investigated the influence of P. gingivalis LPS on the processes of Src activation in rat sublingual gland acinar cells. The LPS-induced enhancement in the activity of inducible (i) iNOS and the impairment in constitutive (c) cNOS were reflected in the suppression in cSrc activity and the extent of its phosphorylation at Tyr416. Further, we show that the countering effect of ghrelin on the LPS-induced changes in cSrc activity and the extent of its phosphorylation was accompanied by a marked reduction in iNOS and the increase in cNOS activation through phosphorylation at Ser1179. Moreover, the effect of ghrelin on cSrc activation was associated with the kinase S-nitrosylation that was susceptible to the blockage by cNOS inhibition. Our findings suggest that P. gingivalis-induced up-regulation in iNOS leads to disturbances in cNOS phosphorylation that exerts the detrimental effect on the processes of cSrc activation through cNOS mediated S-nitrosylation. We also show that the effect of ghrelin on P. gingivalis-induced inflammatory changes are manifested in the enhancement in cSrc activation through S-nitrosylation and the increase in its phosphorylation at Tyr416.展开更多
Ghrelin, a peptide hormone, newly identified in oral mucosal tissue, has emerged re-cently as a principal modulator of the in-flammatory responses to bacterial infection through the regulation of nitric oxide syn-thas...Ghrelin, a peptide hormone, newly identified in oral mucosal tissue, has emerged re-cently as a principal modulator of the in-flammatory responses to bacterial infection through the regulation of nitric oxide syn-thase system. In this study, using rat sub-lingual salivary gland acinar cells, we report that lipopolysaccharide (LPS) of periodon-topathic bacterium, P. gingivalis- induced enhancement in the activity of inducible ni-tric oxide synthase (iNOS) was associated with the suppression in Akt kinase activity and the impairment in constitutive (c) cNOS phosphorylation. Further, we show that the detrimental effect of the LPS on Akt activa-tion, manifested in the kinase protein S-nitrosylation and a decrease in its phos-phorylation at Ser473, was susceptible to suppression by iNOS inhibitor, 1400W. Moreover, we demonstrate that a peptide hormone, ghrelin, countered the LPS- induced changes in Akt activity and NOS system. This effect of ghrelin was reflected in the decreased in Akt S-nitrosylation and the increase in its phosphorylation at Ser473, as well as cNOS activation through phos-phorylation. Our findings suggest that P. gingivalis-induced up-regulation in iNOS leads to Akt kinase inactivation through S-nitrosylation that impacts cNOS activation through phosphorylation. We also show that the countering effect of ghrelin on P. gingivalis-induced disturbances in Akt ac-tivation are manifested in a decrease in the kinase S-nitrosylation and the increase in its phosphorylation.展开更多
Disturbances in nitric oxide synthase (NOS) and cyclooxygenase (COX) isozyme systems, manifested by the excessive NO and prostaglandin (PGE2) generation, are well-recognized features of gastric mucosal inflammatory re...Disturbances in nitric oxide synthase (NOS) and cyclooxygenase (COX) isozyme systems, manifested by the excessive NO and prostaglandin (PGE2) generation, are well-recognized features of gastric mucosal inflammatory responses to H. pylori infection. In this study, we report that H. pylori LPS-induced enhancement in gastric mucosal inducible (i) iNOS expression and COX-2 activation was accompanied by the impairment in constitutive (c) cNOS phosphorylation, up-regulation in the inhibitory κB kinase-β (IKKβ) activation and the increase in the transcriptional factor, NF-κB, nuclear translocation. Further, we show that abrogation of cNOS control over NF-κB activation has lead to induction of iNOS expression and COX-2 activation through S-nitrosylation. Moreover, we demonstrate that the modulatory effect of peptide hormone, ghrelin, on the LPS-induced changes was reflected in the increase in Src/Akt-dependent cNOS activation through phosphorylation and the suppression of IKK-β activity through cNOS-mediated IKK-β protein S-nitrosylation. As a result, ghrelin exerted the inhibitory effect on NF-κB nuclear translocation, thus causing the repression of iNOS gene induction and the inhibition in COX-2 activation through iNOS-dependent S-nitrosylation. Our findings point to cNOS activation as a pivotal element in the signaling cascade by which ghrelin exerts modulatory control over proinflammatory events triggered in gastric mucosa by H. pylori infection.展开更多
Gastric mucosal inflammatory responses to H. pylori lipopolysaccharide (LPS), are characterized by the excessive NO and prostaglandin (PGE2) generation due to the disturbances in nitric oxide synthase (NOS) and cycloo...Gastric mucosal inflammatory responses to H. pylori lipopolysaccharide (LPS), are characterized by the excessive NO and prostaglandin (PGE2) generation due to the disturbances in nitric oxide synthase (NOS) and cyclooxygenase (COX) systems. Here, we report that the LPS-induced enhancement in gastric mucosal inducible (i) iNOS) activity and up-regulation in PGE2 production was associated with the suppression in Akt kinase activity and the impairment in constitutive (c) cNOS activation. The stimulatory effect of the LPS on PGE2 production, furthermore, was susceptible to suppression by COX-2 inhibitor, NS-398, and iNOS inhibitor, 1400 W. Further, we show that the countering effect of peptide hormone, ghrelin, on the LPS-induced changes was reflected in up-regu- lation in Akt activity and the increase in cNOS activation through phosphorylation, and accompanied by the suppression in iNOS expression and the reduction in COX-2 activity associated with the loss in COX-2 protein S-nitrosylation. Moreover, the effect of ghre-lin on the LPS-induced COX-2 S-nitrosylation was subject to repression by Akt inhibition. Our findings demonstrate that induction in iNOS with H. pylori in- fection leads to COX-2 activation through S-nitro- sylation and up-regulation in PGE2 generation, and that ghrelin counters these untoward consequences of the LPS through Akt-mediated up-regulation in cNO- S activation required for the iNOS gene repression.展开更多
Ghrelin, a peptide hormone produced mainly in the stomach, has emerged recently as an important regulator of nitric oxide synthase (NOS) and cyclooxygenase (COX) enzyme systems, the products of which play direct cytop...Ghrelin, a peptide hormone produced mainly in the stomach, has emerged recently as an important regulator of nitric oxide synthase (NOS) and cyclooxygenase (COX) enzyme systems, the products of which play direct cytoprotective function in the maintenance of gastric mucosal integrity. In this study, using gastric mucosal cells, we report on the role of ghrelin in countering the cytotoxic effect of ethanol on mucin synthesis. We show that the countering effect of ghrelin on mucin synthesis was associated with the increase in NO and PGE2 production, and characterized by a marked up-regulation in cytosolic phospholipase A2 (cPLA2) activity. The ghrelin-induced up-regulation in mucin synthesis, like that of cPLA2 activity, was subject to suppression by Src inhibitor, PP2 and ERK inhibitor, PD98059, as well as ascorbate. Moreover, the loss in countering effect of ghrelin on the ethanol cytotoxicity and mucin synthesis was attained with cNOS inhibitor, L-NAME as well as COX-1 inhibitor SC-560. The effect of L-NAME was reflected in the inhibition of ghrelin-induced mucosal cell capacity for NO production, cPLA2 S-nitrosylation and PGE2 generation, whereas COX-1 inhibitor caused only the inhibition in PGE2 generation. Our findings suggest that the activation of gastric mucosal cPLA2 through cNOS-induced S-nitrosylation plays an essential role in the countering effect of ghrelin on the disturbances in gastric mucin synthesis caused by ethanol cytotoxicity.展开更多
Disturbances in nitric oxide synthase (NOS) system and the excessive prostaglandin (PGE2) generation are well-recognized features of oral mucosal inflammatory responses to periodontopathic bacterium, P. gingivalis. Em...Disturbances in nitric oxide synthase (NOS) system and the excessive prostaglandin (PGE2) generation are well-recognized features of oral mucosal inflammatory responses to periodontopathic bacterium, P. gingivalis. Employing rat sublingual gland acinar cells, we show that P. gingivalis LPS-induced up-regulation in PGE2 generation and the enhancement in inducible (i) iNOS activity was associated with COX-2 activation through S-nitrosylation, and accompanied by the suppression in cSrc activity and the impairment in constitutive (c) cNOS phosphorylation. Further, we demonstrate that the countering effect of peptide hormone, ghrelin, on the LPS-induced changes was reflected in the increased cNOS activation through phosphorylation, repression in iNOS induction, and the reduction in PGE2 generation associated with the loss of COX-2 protein S-nitrosylation. Moreover, the effect of ghrelin on cNOS phosphorylation and the LPS-induced COX-2 S-nitrosylation was susceptible to the blockage by cSrc inhibition. Our findings suggest that P. gingivalis-induced up-regulation in iNOS leads to COX-2 S-nitrosylation and up-regulation in PGE2 generation, and that the countering effect of ghrelin is mediated through Src-dependent cNOS activation that is obligatory for the maintenance of iNOS gene suppression.展开更多
The S-Nitrosylation of protein thiol groups by NO is a widely recognized protein modification. The treat-ment of cells with NOBF4 induces the S-nitrosylation of FE65. In this study, we present evidence showing that FE...The S-Nitrosylation of protein thiol groups by NO is a widely recognized protein modification. The treat-ment of cells with NOBF4 induces the S-nitrosylation of FE65. In this study, we present evidence showing that FE65 modified by NO (Nitric Oxide) via S-nitrosylation induces functional changes in the protein that inhibits the HAT activity of Tip60. The results of mutational analysis of FE65 demonstrated further that the cysteine residue of FE65 (Cys440) is critical to the process of S-nitrosylation. The mutation of the cysteine residue which completely ablated the S-nitrosylation of FE65 also lost its inhibitory effects on Tip60 HAT activity. Thus, our findings show, for the first time, that the novel regulation mechanism of Tip60 activity may operate via FE65 binding, which is enhanced by S-nitrosylation on the FE65 Cys440 residue. This study describes the interaction between FE65 and Tip60, which is enhanced by a posttransla-tional modification of FE65 (through S-nitrosylation) by NO, promoting the association of the FE65-Tip60 protein complex and inhibiting both the HAT activity of Tip60 and cell death.展开更多
Protein post-translational modifications such as phosphorylation and S-nitrosylation regulate protein functions and cellular programs in eukaryotes.Moreover,extensive evidence suggests crosstalk between these modifica...Protein post-translational modifications such as phosphorylation and S-nitrosylation regulate protein functions and cellular programs in eukaryotes.Moreover,extensive evidence suggests crosstalk between these modifications.However,we lack a comprehensive method for the simultaneous detection and analysis of multiple post-translational modifications.Here,we present an optimized workflow that identifies phosphorylation and S-nitrosylation sites using a novel phosphate affinity tag switch technique.Validation with model proteins and complex biological samples confirmed the high sensitivity,coverage,and reproducibility of this method.Applying this method to Arabidopsis thaliana seedlings revealed 12,552 phosphorylation sites and 6,108 S-nitrosylation sites,representing the largest single-study dataset of S-nitrosylation sites to date.This approach enhances our understanding of post-translational modification dynamics in plant signaling,stress responses,and metabolism.展开更多
Background:Keloids are aberrant dermal wound healing characterized by invasive growth,extracellular matrix deposition,cytokine overexpression and easy recurrence.Many factors have been implicated as pathological cause...Background:Keloids are aberrant dermal wound healing characterized by invasive growth,extracellular matrix deposition,cytokine overexpression and easy recurrence.Many factors have been implicated as pathological causes of keloids,particularly hyperactive inflammation,tension alignment and genetic predisposition.S-Nitrosylation(SNO),a unique form of protein modification,is associated with the local inflammatory response but its function in excessive fibrosis and keloid formation remains unknown.We aimed to discover the association between protein SNO and keloid formation.Methods:Normal and keloid fibroblasts were isolated from collected normal skin and keloid tissues.The obtained fibroblasts were cultured in DMEM supplemented with 10%fetal bovine serum and 1%penicillin/streptomycin.The effects of DJ-1 on cell proliferation,apoptosis,migration and invasion,and on the expression of proteins were assayed.TurboID-based proximity labelling and liquid chromatography-mass spectrometry were conducted to explore the potential targets of DJ-1.Biotin-switch assays and transnitrosylation reactions were used to detect protein SNO.Quantitative data were compared by two-tailed Student’s t test.Results:We found that DJ-1 served as an essential positive modulator to facilitate keloid cell proliferation,migration and invasion.A higher S-nitrosylated DJ-1(SNO-DJ-1)level was observed in keloids,and the effect of DJ-1 on keloids was dependent on SNO of the Cys106 residue of the DJ-1 protein.SNO-DJ-1 was found to increase the level of phosphatase and tensin homolog(PTEN)S-nitrosylated at its Cys136 residue via transnitrosylation in keloids,thus diminishing the phosphatase activity of PTEN and activating the PI3K/AKT/mTOR pathway.Furthermore,Cys106-mutant DJ-1 is refractory to SNO and abrogates DJ-1-PTEN coupling and the SNO of the PTEN protein,thus repressing the PI3K/AKT/mTOR pathway and alleviating keloid formation.Importantly,the biological effect of DJ-1 in keloids is dependent on the SNO-DJ-1/SNO-PTEN/PI3K/AKT/mTOR axis.Conclusions:For the first time,this study demonstrated the effect of transnitrosylation from DJ-1 to PTEN on promoting keloid formation via the PI3K/AKT/mTOR signaling pathway,suggesting that SNO of DJ-1 may be a novel therapeutic target for keloid treatment.展开更多
Nitric oxide （NO） as an immunoregulatory molecule, predominantly depending on S-nitrosylation, acts as a versatile player that executes its regulation and signal transduction for exerting its multi-functions and ple...Nitric oxide （NO） as an immunoregulatory molecule, predominantly depending on S-nitrosylation, acts as a versatile player that executes its regulation and signal transduction for exerting its multi-functions and pleiotropy. Apoptosis of immune cells is an intricate process coupled with positive/negative selection depending on integrated diverse endogenous and exogenous signals and functions to sustain homeostasis in the immune system. Here, the dual roles of NO depending on its concentration in apoptosis are reviewed, breeding up a switch mode in the apoptotic process. Following comments of different switches from apoptosis-death, a new finding of checkpoint （early fluorescence point） of GSNO-initiated thymocyte apoptosis and NOS-GSNOR double control are highlighted. Moreover, S-nitrosylation/denitrosylation, being as a redox switch, logically approaches to networks of metabolism itself and further accesses the neuroendicrine-immune-free radical network as a whole. Moreover, the host defense mediated by NO on pathogens, via protein S-nitrosylation are also discussed.展开更多
A dilemma about whether thionitroxide radical (RSNHO) or S-nitrosothiol (RSNO) is observed in protein S-nitrosylation has arisen recently. To illustrate the effect of chemical environment on these structures, this pap...A dilemma about whether thionitroxide radical (RSNHO) or S-nitrosothiol (RSNO) is observed in protein S-nitrosylation has arisen recently. To illustrate the effect of chemical environment on these structures, this paper presents quantum mechanical molecular dynamics of thionitroxide, and cis-and trans-S-nitrosothiols in the gas phase, methanol, and water. By using Car-Parrinello molecular dynamics (CPMD), we have observed that there is free rotation about the S-N bond at 300 K in thionitroxide, but no such rotation is observed for S-nitrosothiol. The C-S-N-O torsion angle distribution in thionitroxide is s-ignificantly dependent upon the surrounding environment, leading to either gauche-, cis-, or trans-conformation. In the case of S-nitrosothiol the C-S-N-O plane is twisted slightly by 5°-15° in the cis-isomer, while the periplanar structure is well-retained in the trans-isomer. The calculated results are in agreement with the X-ray crystallographic data of small molecular RSNO species. Interestingly, for both compounds, the CPMD simulations show that solvation can cause a decrease in the S-N bond length. Moreover, the oxygen atom of thionitroxide is found to be a good hydrogen-bond acceptor, forming an oxyanion-hole-like hydrogen bonding network.展开更多
Neural growth inhibitory factor （GIF）, a member of metallothionein family （metallothionein-3, MT3）, was well known by its distinct neural growth inhibitory activity, which is not shown by other MT isoforms. Howeve...Neural growth inhibitory factor （GIF）, a member of metallothionein family （metallothionein-3, MT3）, was well known by its distinct neural growth inhibitory activity, which is not shown by other MT isoforms. However, till now, people still did not know clearly how GIF exerts its biological functions. Since it has been reported that GIF might serve as NO scavenger and was related to the release of zinc, our study was focused on the interaction of GIF and NO. By studying the reactions of human GIF and human MTlg with SNOC-a type of NO donor, it was found that GIF was more reactive than MT-lg toward SNOC. In order to further figure out if the high reactivity of GIF in this reaction resulted from the acid-base catalysis, several mutants were constructed： E23K, E41G/E43A, E23K/E41G/E43A. By studying their basic properties and the reactions toward SNOC, it was found that the S-nitrosylation of GIF was not only related to the acid-base catalysis, but also to the accessibility of metal-thiolate clusters.展开更多
In response to dynamically altered environments,plants must finely coordinate the balance between growth and stress responses for their survival.However,the underpinning regulatory mechanisms remain largely elusive.Th...In response to dynamically altered environments,plants must finely coordinate the balance between growth and stress responses for their survival.However,the underpinning regulatory mechanisms remain largely elusive.The phytohormone gibberellin promotes growth via a derepression mechanism by proteasomal degradation of the DELLA transcription repressors.Conversely,the stress-induced burst of nitric oxide(NO)enhances stress tolerance,largely relying on NO-mediated S-nitrosylation,a redox-based posttranslational modification.Here,we show that S-nitrosylation of Cys-374 in the Arabidopsis RGA protein,a key member of DELLAs,inhibits its interaction with the F-box protein SLY1,thereby preventing its proteasomal degradation under salinity condition.The accumulation of RGA consequently retards growth but enhances salt tolerance.We propose that NO negatively regulates gibberellin signaling via S-nitrosylation of RGA to coordinate the balance of growth and stress responses when challenged by adverse environments.展开更多
In plants,the ubiquitin–proteasome system(UPS)plays a central role in hormonal regulation,including the action of the phytohormone auxin,which orchestrates numerous aspects of growth and development.Auxin modulates r...In plants,the ubiquitin–proteasome system(UPS)plays a central role in hormonal regulation,including the action of the phytohormone auxin,which orchestrates numerous aspects of growth and development.Auxin modulates redox metabolism and promotes the accumulation of nitric oxide(NO)in various tissues and physiological contexts.NO functions as a redox signaling molecule,exerting its effects in part through the reversible oxidation of cysteine residues via a post-translational modification known as S-nitrosylation.Recent findings highlight a dynamic interplay between S-nitrosylation and the ubiquitination machinery,shaping critical aspects of auxin-mediated plant responses.In this review,we summarize current knowledge on redox regulation of UPS components involved in auxinmediated pathways and propose new perspectives on the integration of hormonal and redox signaling in plants.We describe and discuss the complexity of the latest evidence supporting the role of NO as a second messenger in auxin signaling,with S-nitrosylation acting as a regulatory mechanism that fine-tunes the UPS to control developmental outcomes.We focused on the direct effects of NO that include S-nitrosylation of specific cysteine residues of substrates,adaptors,and substrate receptors belonging to different CULLIN1-and CULLIN4-based E3 ubiquitin ligase complexes.展开更多
Protein S-nitrosation(SNO),an essential posttranslational modification(PTM)elicited by nitric oxide(NO)1,regulates a broad range of physiological/pathological processes2.Recently,a study led by Jonathan Stamler3 publi...Protein S-nitrosation(SNO),an essential posttranslational modification(PTM)elicited by nitric oxide(NO)1,regulates a broad range of physiological/pathological processes2.Recently,a study led by Jonathan Stamler3 published in Cell explores the discovery and characterization of an enzyme that selectively S-nitrosylates proteins to regulate insulin signaling.展开更多
Nitric oxide(NO)has emerged as an important signal molecule in plants,having myriad roles in plant devel-opment.In addition,NO also orchestrates both biotic and abiotic stress responses,during which intensive cellular...Nitric oxide(NO)has emerged as an important signal molecule in plants,having myriad roles in plant devel-opment.In addition,NO also orchestrates both biotic and abiotic stress responses,during which intensive cellular metabolic reprogramming occurs.Integral to these responses is the location of NO biosynthetic and scavenging pathways in diverse cellular compartments,enabling plants to effectively organize signal transduction pathways.NO regulates plant metabolism and,in turn,metabolic pathways reciprocally regu-late NO accumulation and function.Thus,these diverse cellular processes are inextricably linked.This re-view addresses the numerous redox pathways,located in the various subcellular compartments that pro-duce NO,in addition to the mechanisms underpinning NO scavenging.We focus on how this molecular dance is integrated into the metabolic state of the cell.Within this context,a reciprocal relationship be-tween NO accumulation and metabolite production is often apparent.We also showcase cellular pathways,including those associated with nitrate reduction,that provide evidence for this integration of NO function and metabolism.Finally,we discuss the potential importance of the biochemical reactions governing NO levels in determining plant responses to a changing environment.展开更多
Post-translational modifications(PTMs)are central to the modulation of protein activity,stability,subcellular localization,and interaction with partners.They greatly expand the diversity and functionality of the prote...Post-translational modifications(PTMs)are central to the modulation of protein activity,stability,subcellular localization,and interaction with partners.They greatly expand the diversity and functionality of the proteome and have taken the center stage as key players in regulating numerous cellular and physiological processes.Increasing evidence indicates that in addition to a single regulatory PTM,many proteins are modified by multiple different types of PTMs in an orchestrated manner to collectively modulate the biological outcome.Such PTM crosstalk creates a combinatorial explosion in the number of proteoforms in a cell and greatly improves the ability of plants to rapidly mount and fine-tune responses to different external and internal cues.While PTM crosstalk has been investigated in depth in humans,animals,and yeast,the study of interplay between different PTMs in plants is still at its infant stage.In the past decade,investigations showed that PTMs are widely involved and play critical roles in the regulation of interactions between plants and pathogens.In particular,ubiquitination has emerged as a key regulator of plant immunity.This review discusses recent studies of the crosstalk between ubiquitination and six other PTMs,i.e.,phosphorylation,SUMOylation,poly(ADP-ribosyl)ation,acetylation,redox modification,and glycosylation,in the regulation of plant immunity.The two basic ways by which PTMs communicate as well as the underlying mechanisms and diverse outcomes of the PTM crosstalk in plant immunity are highlighted.展开更多
Cross talk between phytohormones, nitric oxide （NO）, and auxin has been implicated in the control of plant growth and development. Two recent reports indicate that NO promoted auxin signaling but inhibited auxin tra...Cross talk between phytohormones, nitric oxide （NO）, and auxin has been implicated in the control of plant growth and development. Two recent reports indicate that NO promoted auxin signaling but inhibited auxin transport probably through S-nitrosylation. However, genetic evidence for the effect of S-nitrosylation on auxin physiology has been lacking. In this study, we used a genetic approach to understand the broader role of S-nitrosylation in auxin physiology in Arabidopsis. We compared auxin signaling and transport in Col-0 and gsnorl-3, a loss-of-function GSNOR1 mutant defective in protein de-nitrosylation. Our results showed that auxin signaling was impaired in the gsnorl-3 mutant as revealed by significantly reduced DR5-GUS/ DR5-GFP accumulation and compromised degradation of AXR3NT-GUS, a useful reporter in interrogating auxin-mediated degradation of Aux/IAA by auxin receptors. In addition, polar auxin transport was compro- mised in gsnorl-3, which was correlated with universally reduced levels of PIN or GFP-PIN proteins in the roots of the mutant in a manner independent of transcription and 26S proteasome degradation. Our results suggest that S-nitrosylation and GSNORl-mediated de-nitrosylation contribute to auxin physiology, and impaired auxin signaling and compromised auxin transport are responsible for the auxin-related morpho- logical phenotypes displayed by the gsnorl-3 mutant.展开更多
基金Supported by the National Natural Science Foundation of China(No.42276100)the Project Funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)。
文摘Ulva prolifera,the primary causative species of green tide,has garnered significant attention due to its robust growth and reproductive capacity under high salt stress.However,there has been relatively little research on the regulation of high salt stress in this species.In this study,we observed that high salt stress suppressed the growth of U.prolifera and leading to the nitric oxide(NO)accumulation,along with increased gene expression levels and enzyme activity of S-nitrosoglutathione reductase(GSNOR).Treatment with GSNOR inhibitor resulted in elevated NO levels under high salt stress,accompanied by reduced activity of antioxidant enzymes and decreased glutathione(GSH)accumulation,making U.prolifera more sensitive to high salt stress.Conversely,NO scavenger treatment not only reduced NO levels,but also weakened the high salt stress tolerance of U.prolifera.Furthermore,using tandem mass tags(TMT)switch analysis and mass spectrometry,we observed a significant increase in S nitrosylated protein levels in U.prolifera under high salt stress,with further augmentation upon GSNOR inhibitor treatment.We also found high salt stress induced S-nitrosylation(SNO)of glutathione reductase(GR),which is negatively regulated by GSNOR,resulting in increased GR activity.Our results show that under short-term high salt stress,the elevated expression level of GSNOR avoided excessive accumulation of NO,and a certain amount of NO enhanced the activity of antioxidant enzymes through SNO modification,which improve the high salt stress tolerance of U.prolifera,whereas under long-term high salt stress,excessive NO was toxic to U.prolifera.
基金supported by grants from the National Natural Science Foundation of China (31830017)Chinese Academy of Sciences (XDB27030207)+1 种基金the Hainan Excellent Talent TeamState Key Laboratory of Plant Genomics (SKLPG2023-22)
文摘The phytohormone auxin plays crucial roles in nearly every aspect of plant growth and development.Auxin signaling is activated through the phytohormone-induced proteasomal degradation of the Auxin/INDOLE-3-ACETIC ACID(Aux/IAA)family of transcriptional repressors.Notably,many auxin-modulated physiological processes are also regulated by nitric oxide(NO)that executes its biological effects predominantly through protein S-nitrosylation at specific cysteine residues.However,little is known about the molecular mechanisms in regulating the interactive NO and auxin networks.Here,we show that NO represses auxin signaling by inhibiting IAA17 protein degradation.NO induces the S-nitrosylation of Cys-70 located in the intrinsically disordered region of IAA17,which inhibits the TIR1-IAA17 interaction and consequently the proteasomal degradation of IAA17.The accumulation of a higher level of IAA17 attenuates auxin response.Moreover,an IAA17^(C70W)nitrosomimetic mutation renders the accumulation of a higher level of the mutated protein,thereby causing partial resistance to auxin and defective lateral root development.Taken together,these results suggest that S-nitrosylation of IAA17 at Cys-70 inhibits its interaction with TIR1,thereby negatively regulating auxin signaling.This study provides unique molecular insights into the redox-based auxin signaling in regulating plant growth and development.
文摘A peptide hormone, ghrelin, recognized for its role in the regulation of nitric oxide production has emerged as an important modulator of oral mucosal inflammatory responses to periodontopathic bacterium, P. gingivalis. As cSrc kinase plays a major role in controlling the activity of nitric oxide synthase (NOS) system, in this study we investigated the influence of P. gingivalis LPS on the processes of Src activation in rat sublingual gland acinar cells. The LPS-induced enhancement in the activity of inducible (i) iNOS and the impairment in constitutive (c) cNOS were reflected in the suppression in cSrc activity and the extent of its phosphorylation at Tyr416. Further, we show that the countering effect of ghrelin on the LPS-induced changes in cSrc activity and the extent of its phosphorylation was accompanied by a marked reduction in iNOS and the increase in cNOS activation through phosphorylation at Ser1179. Moreover, the effect of ghrelin on cSrc activation was associated with the kinase S-nitrosylation that was susceptible to the blockage by cNOS inhibition. Our findings suggest that P. gingivalis-induced up-regulation in iNOS leads to disturbances in cNOS phosphorylation that exerts the detrimental effect on the processes of cSrc activation through cNOS mediated S-nitrosylation. We also show that the effect of ghrelin on P. gingivalis-induced inflammatory changes are manifested in the enhancement in cSrc activation through S-nitrosylation and the increase in its phosphorylation at Tyr416.
文摘Ghrelin, a peptide hormone, newly identified in oral mucosal tissue, has emerged re-cently as a principal modulator of the in-flammatory responses to bacterial infection through the regulation of nitric oxide syn-thase system. In this study, using rat sub-lingual salivary gland acinar cells, we report that lipopolysaccharide (LPS) of periodon-topathic bacterium, P. gingivalis- induced enhancement in the activity of inducible ni-tric oxide synthase (iNOS) was associated with the suppression in Akt kinase activity and the impairment in constitutive (c) cNOS phosphorylation. Further, we show that the detrimental effect of the LPS on Akt activa-tion, manifested in the kinase protein S-nitrosylation and a decrease in its phos-phorylation at Ser473, was susceptible to suppression by iNOS inhibitor, 1400W. Moreover, we demonstrate that a peptide hormone, ghrelin, countered the LPS- induced changes in Akt activity and NOS system. This effect of ghrelin was reflected in the decreased in Akt S-nitrosylation and the increase in its phosphorylation at Ser473, as well as cNOS activation through phos-phorylation. Our findings suggest that P. gingivalis-induced up-regulation in iNOS leads to Akt kinase inactivation through S-nitrosylation that impacts cNOS activation through phosphorylation. We also show that the countering effect of ghrelin on P. gingivalis-induced disturbances in Akt ac-tivation are manifested in a decrease in the kinase S-nitrosylation and the increase in its phosphorylation.
文摘Disturbances in nitric oxide synthase (NOS) and cyclooxygenase (COX) isozyme systems, manifested by the excessive NO and prostaglandin (PGE2) generation, are well-recognized features of gastric mucosal inflammatory responses to H. pylori infection. In this study, we report that H. pylori LPS-induced enhancement in gastric mucosal inducible (i) iNOS expression and COX-2 activation was accompanied by the impairment in constitutive (c) cNOS phosphorylation, up-regulation in the inhibitory κB kinase-β (IKKβ) activation and the increase in the transcriptional factor, NF-κB, nuclear translocation. Further, we show that abrogation of cNOS control over NF-κB activation has lead to induction of iNOS expression and COX-2 activation through S-nitrosylation. Moreover, we demonstrate that the modulatory effect of peptide hormone, ghrelin, on the LPS-induced changes was reflected in the increase in Src/Akt-dependent cNOS activation through phosphorylation and the suppression of IKK-β activity through cNOS-mediated IKK-β protein S-nitrosylation. As a result, ghrelin exerted the inhibitory effect on NF-κB nuclear translocation, thus causing the repression of iNOS gene induction and the inhibition in COX-2 activation through iNOS-dependent S-nitrosylation. Our findings point to cNOS activation as a pivotal element in the signaling cascade by which ghrelin exerts modulatory control over proinflammatory events triggered in gastric mucosa by H. pylori infection.
文摘Gastric mucosal inflammatory responses to H. pylori lipopolysaccharide (LPS), are characterized by the excessive NO and prostaglandin (PGE2) generation due to the disturbances in nitric oxide synthase (NOS) and cyclooxygenase (COX) systems. Here, we report that the LPS-induced enhancement in gastric mucosal inducible (i) iNOS) activity and up-regulation in PGE2 production was associated with the suppression in Akt kinase activity and the impairment in constitutive (c) cNOS activation. The stimulatory effect of the LPS on PGE2 production, furthermore, was susceptible to suppression by COX-2 inhibitor, NS-398, and iNOS inhibitor, 1400 W. Further, we show that the countering effect of peptide hormone, ghrelin, on the LPS-induced changes was reflected in up-regu- lation in Akt activity and the increase in cNOS activation through phosphorylation, and accompanied by the suppression in iNOS expression and the reduction in COX-2 activity associated with the loss in COX-2 protein S-nitrosylation. Moreover, the effect of ghre-lin on the LPS-induced COX-2 S-nitrosylation was subject to repression by Akt inhibition. Our findings demonstrate that induction in iNOS with H. pylori in- fection leads to COX-2 activation through S-nitro- sylation and up-regulation in PGE2 generation, and that ghrelin counters these untoward consequences of the LPS through Akt-mediated up-regulation in cNO- S activation required for the iNOS gene repression.
文摘Ghrelin, a peptide hormone produced mainly in the stomach, has emerged recently as an important regulator of nitric oxide synthase (NOS) and cyclooxygenase (COX) enzyme systems, the products of which play direct cytoprotective function in the maintenance of gastric mucosal integrity. In this study, using gastric mucosal cells, we report on the role of ghrelin in countering the cytotoxic effect of ethanol on mucin synthesis. We show that the countering effect of ghrelin on mucin synthesis was associated with the increase in NO and PGE2 production, and characterized by a marked up-regulation in cytosolic phospholipase A2 (cPLA2) activity. The ghrelin-induced up-regulation in mucin synthesis, like that of cPLA2 activity, was subject to suppression by Src inhibitor, PP2 and ERK inhibitor, PD98059, as well as ascorbate. Moreover, the loss in countering effect of ghrelin on the ethanol cytotoxicity and mucin synthesis was attained with cNOS inhibitor, L-NAME as well as COX-1 inhibitor SC-560. The effect of L-NAME was reflected in the inhibition of ghrelin-induced mucosal cell capacity for NO production, cPLA2 S-nitrosylation and PGE2 generation, whereas COX-1 inhibitor caused only the inhibition in PGE2 generation. Our findings suggest that the activation of gastric mucosal cPLA2 through cNOS-induced S-nitrosylation plays an essential role in the countering effect of ghrelin on the disturbances in gastric mucin synthesis caused by ethanol cytotoxicity.
文摘Disturbances in nitric oxide synthase (NOS) system and the excessive prostaglandin (PGE2) generation are well-recognized features of oral mucosal inflammatory responses to periodontopathic bacterium, P. gingivalis. Employing rat sublingual gland acinar cells, we show that P. gingivalis LPS-induced up-regulation in PGE2 generation and the enhancement in inducible (i) iNOS activity was associated with COX-2 activation through S-nitrosylation, and accompanied by the suppression in cSrc activity and the impairment in constitutive (c) cNOS phosphorylation. Further, we demonstrate that the countering effect of peptide hormone, ghrelin, on the LPS-induced changes was reflected in the increased cNOS activation through phosphorylation, repression in iNOS induction, and the reduction in PGE2 generation associated with the loss of COX-2 protein S-nitrosylation. Moreover, the effect of ghrelin on cNOS phosphorylation and the LPS-induced COX-2 S-nitrosylation was susceptible to the blockage by cSrc inhibition. Our findings suggest that P. gingivalis-induced up-regulation in iNOS leads to COX-2 S-nitrosylation and up-regulation in PGE2 generation, and that the countering effect of ghrelin is mediated through Src-dependent cNOS activation that is obligatory for the maintenance of iNOS gene suppression.
文摘The S-Nitrosylation of protein thiol groups by NO is a widely recognized protein modification. The treat-ment of cells with NOBF4 induces the S-nitrosylation of FE65. In this study, we present evidence showing that FE65 modified by NO (Nitric Oxide) via S-nitrosylation induces functional changes in the protein that inhibits the HAT activity of Tip60. The results of mutational analysis of FE65 demonstrated further that the cysteine residue of FE65 (Cys440) is critical to the process of S-nitrosylation. The mutation of the cysteine residue which completely ablated the S-nitrosylation of FE65 also lost its inhibitory effects on Tip60 HAT activity. Thus, our findings show, for the first time, that the novel regulation mechanism of Tip60 activity may operate via FE65 binding, which is enhanced by S-nitrosylation on the FE65 Cys440 residue. This study describes the interaction between FE65 and Tip60, which is enhanced by a posttransla-tional modification of FE65 (through S-nitrosylation) by NO, promoting the association of the FE65-Tip60 protein complex and inhibiting both the HAT activity of Tip60 and cell death.
基金support of the Science and Technology Program of Guangdong Province(2023A0505090005,2021TQ06N115)the Natural Science Foundation of Guangdong Province(2022A1515110962)+1 种基金the Special Fund for Scientific Innovation Strategy-Construction of High-Level Academy of Agriculture Science(R2021YJ-YB3010,R2023PY-JG025,2023QZ-NK04,GDNKY-ZQQZ-K5)Modern Seed Industry Innovation Capability Enhancement Project of Guangdong Academy of Agricultural Sciences.
文摘Protein post-translational modifications such as phosphorylation and S-nitrosylation regulate protein functions and cellular programs in eukaryotes.Moreover,extensive evidence suggests crosstalk between these modifications.However,we lack a comprehensive method for the simultaneous detection and analysis of multiple post-translational modifications.Here,we present an optimized workflow that identifies phosphorylation and S-nitrosylation sites using a novel phosphate affinity tag switch technique.Validation with model proteins and complex biological samples confirmed the high sensitivity,coverage,and reproducibility of this method.Applying this method to Arabidopsis thaliana seedlings revealed 12,552 phosphorylation sites and 6,108 S-nitrosylation sites,representing the largest single-study dataset of S-nitrosylation sites to date.This approach enhances our understanding of post-translational modification dynamics in plant signaling,stress responses,and metabolism.
基金supported by grants from the National Natural Science Foundation of China(No.82272273,No.82072181,No.81871565,No.81571908)the Sun Yat-sen University Clinical Research 5010 Program(No.2018003).
文摘Background:Keloids are aberrant dermal wound healing characterized by invasive growth,extracellular matrix deposition,cytokine overexpression and easy recurrence.Many factors have been implicated as pathological causes of keloids,particularly hyperactive inflammation,tension alignment and genetic predisposition.S-Nitrosylation(SNO),a unique form of protein modification,is associated with the local inflammatory response but its function in excessive fibrosis and keloid formation remains unknown.We aimed to discover the association between protein SNO and keloid formation.Methods:Normal and keloid fibroblasts were isolated from collected normal skin and keloid tissues.The obtained fibroblasts were cultured in DMEM supplemented with 10%fetal bovine serum and 1%penicillin/streptomycin.The effects of DJ-1 on cell proliferation,apoptosis,migration and invasion,and on the expression of proteins were assayed.TurboID-based proximity labelling and liquid chromatography-mass spectrometry were conducted to explore the potential targets of DJ-1.Biotin-switch assays and transnitrosylation reactions were used to detect protein SNO.Quantitative data were compared by two-tailed Student’s t test.Results:We found that DJ-1 served as an essential positive modulator to facilitate keloid cell proliferation,migration and invasion.A higher S-nitrosylated DJ-1(SNO-DJ-1)level was observed in keloids,and the effect of DJ-1 on keloids was dependent on SNO of the Cys106 residue of the DJ-1 protein.SNO-DJ-1 was found to increase the level of phosphatase and tensin homolog(PTEN)S-nitrosylated at its Cys136 residue via transnitrosylation in keloids,thus diminishing the phosphatase activity of PTEN and activating the PI3K/AKT/mTOR pathway.Furthermore,Cys106-mutant DJ-1 is refractory to SNO and abrogates DJ-1-PTEN coupling and the SNO of the PTEN protein,thus repressing the PI3K/AKT/mTOR pathway and alleviating keloid formation.Importantly,the biological effect of DJ-1 in keloids is dependent on the SNO-DJ-1/SNO-PTEN/PI3K/AKT/mTOR axis.Conclusions:For the first time,this study demonstrated the effect of transnitrosylation from DJ-1 to PTEN on promoting keloid formation via the PI3K/AKT/mTOR signaling pathway,suggesting that SNO of DJ-1 may be a novel therapeutic target for keloid treatment.
基金The work was supported by the National Basic Research Program of China （2006CB911000, 2006CB503900）the National Natural Science Foundation of China （30770512, 39770202）.
文摘Nitric oxide （NO） as an immunoregulatory molecule, predominantly depending on S-nitrosylation, acts as a versatile player that executes its regulation and signal transduction for exerting its multi-functions and pleiotropy. Apoptosis of immune cells is an intricate process coupled with positive/negative selection depending on integrated diverse endogenous and exogenous signals and functions to sustain homeostasis in the immune system. Here, the dual roles of NO depending on its concentration in apoptosis are reviewed, breeding up a switch mode in the apoptotic process. Following comments of different switches from apoptosis-death, a new finding of checkpoint （early fluorescence point） of GSNO-initiated thymocyte apoptosis and NOS-GSNOR double control are highlighted. Moreover, S-nitrosylation/denitrosylation, being as a redox switch, logically approaches to networks of metabolism itself and further accesses the neuroendicrine-immune-free radical network as a whole. Moreover, the host defense mediated by NO on pathogens, via protein S-nitrosylation are also discussed.
基金supported by the National High-Tech R&DProgram of China "863" (2012AA020403)the National Basic Research Program of China "973" (2012CB72100)+3 种基金Shanghai Municipal Council of Science and Technology (10PJ1405200)the Specialized Research Fund for the Doctoral Program of Higher Education (Z1025507)Shanghai Municipal Education Commission (Oriental Professorial Scholarship 0900000171)the National Natural Science Foundation of China (30821005)
文摘A dilemma about whether thionitroxide radical (RSNHO) or S-nitrosothiol (RSNO) is observed in protein S-nitrosylation has arisen recently. To illustrate the effect of chemical environment on these structures, this paper presents quantum mechanical molecular dynamics of thionitroxide, and cis-and trans-S-nitrosothiols in the gas phase, methanol, and water. By using Car-Parrinello molecular dynamics (CPMD), we have observed that there is free rotation about the S-N bond at 300 K in thionitroxide, but no such rotation is observed for S-nitrosothiol. The C-S-N-O torsion angle distribution in thionitroxide is s-ignificantly dependent upon the surrounding environment, leading to either gauche-, cis-, or trans-conformation. In the case of S-nitrosothiol the C-S-N-O plane is twisted slightly by 5°-15° in the cis-isomer, while the periplanar structure is well-retained in the trans-isomer. The calculated results are in agreement with the X-ray crystallographic data of small molecular RSNO species. Interestingly, for both compounds, the CPMD simulations show that solvation can cause a decrease in the S-N bond length. Moreover, the oxygen atom of thionitroxide is found to be a good hydrogen-bond acceptor, forming an oxyanion-hole-like hydrogen bonding network.
文摘Neural growth inhibitory factor （GIF）, a member of metallothionein family （metallothionein-3, MT3）, was well known by its distinct neural growth inhibitory activity, which is not shown by other MT isoforms. However, till now, people still did not know clearly how GIF exerts its biological functions. Since it has been reported that GIF might serve as NO scavenger and was related to the release of zinc, our study was focused on the interaction of GIF and NO. By studying the reactions of human GIF and human MTlg with SNOC-a type of NO donor, it was found that GIF was more reactive than MT-lg toward SNOC. In order to further figure out if the high reactivity of GIF in this reaction resulted from the acid-base catalysis, several mutants were constructed： E23K, E41G/E43A, E23K/E41G/E43A. By studying their basic properties and the reactions toward SNOC, it was found that the S-nitrosylation of GIF was not only related to the acid-base catalysis, but also to the accessibility of metal-thiolate clusters.
基金supported by grants from the National Natural Science Foundation of China (31830017 and 31521001)Chinese Academy of Sciences (XDB27030207)State Key Laboratory of Plant Genomics (SKLPG2020-22)
文摘In response to dynamically altered environments,plants must finely coordinate the balance between growth and stress responses for their survival.However,the underpinning regulatory mechanisms remain largely elusive.The phytohormone gibberellin promotes growth via a derepression mechanism by proteasomal degradation of the DELLA transcription repressors.Conversely,the stress-induced burst of nitric oxide(NO)enhances stress tolerance,largely relying on NO-mediated S-nitrosylation,a redox-based posttranslational modification.Here,we show that S-nitrosylation of Cys-374 in the Arabidopsis RGA protein,a key member of DELLAs,inhibits its interaction with the F-box protein SLY1,thereby preventing its proteasomal degradation under salinity condition.The accumulation of RGA consequently retards growth but enhances salt tolerance.We propose that NO negatively regulates gibberellin signaling via S-nitrosylation of RGA to coordinate the balance of growth and stress responses when challenged by adverse environments.
基金supported by grants from CONICET(PIP 0237 to MCT)Agencia Nacional de Promoción Científica y Tecnológica(ANPCYT,grant PICT-2020-0178 to MJI)Universidad Nacional deMar del Plata(EXA 1217/24 and 1179/24 to MCT).
文摘In plants,the ubiquitin–proteasome system(UPS)plays a central role in hormonal regulation,including the action of the phytohormone auxin,which orchestrates numerous aspects of growth and development.Auxin modulates redox metabolism and promotes the accumulation of nitric oxide(NO)in various tissues and physiological contexts.NO functions as a redox signaling molecule,exerting its effects in part through the reversible oxidation of cysteine residues via a post-translational modification known as S-nitrosylation.Recent findings highlight a dynamic interplay between S-nitrosylation and the ubiquitination machinery,shaping critical aspects of auxin-mediated plant responses.In this review,we summarize current knowledge on redox regulation of UPS components involved in auxinmediated pathways and propose new perspectives on the integration of hormonal and redox signaling in plants.We describe and discuss the complexity of the latest evidence supporting the role of NO as a second messenger in auxin signaling,with S-nitrosylation acting as a regulatory mechanism that fine-tunes the UPS to control developmental outcomes.We focused on the direct effects of NO that include S-nitrosylation of specific cysteine residues of substrates,adaptors,and substrate receptors belonging to different CULLIN1-and CULLIN4-based E3 ubiquitin ligase complexes.
基金supported by grants from the Natural Science Foundation of Xinjiang Uygur Autonomous Region(2022D01D38 and 2023D01D16,China)the National Natural Science Foundation of China(No.82473773,82173681,82104004 and 82273780)+3 种基金the Key Research and Development Program of Xinjiang Uygur Autonomous Region(2023B03012-1,China)the Prevention and Treatment of High Incidence Diseases in Central Asia Fund(SKL-HIDCA-2024-4,China)the Fundamental Research Funds for the Central Universities of China Pharmaceutical University(No.2632023TD04,China)the“Double First-Class”University projects(CPU2022PZQ15 from China Pharmaceutical University,China).
文摘Protein S-nitrosation(SNO),an essential posttranslational modification(PTM)elicited by nitric oxide(NO)1,regulates a broad range of physiological/pathological processes2.Recently,a study led by Jonathan Stamler3 published in Cell explores the discovery and characterization of an enzyme that selectively S-nitrosylates proteins to regulate insulin signaling.
基金supported by SERB core grant CRG/2019/004534 and DBT project BT/PR23711/BPA/118/343/2017.Work on vitamin Bp and N meta-bolism in the labs of KJ.G.and T.B.F.is supported by an Indo-Swiss Joint Aesearch Programme on Blue Siy Research DBTIN/Swiss/47/JGKV 2018-19 and IZLZ3.183193.Work on nitric oxide in the G.J.L.lab is sup-ported by the BSAC,the Darwin Trust,and the Wellcome Tust.Work in the lab ofT.B.F.is supported by the SNF(grant 31003A-141117/1)and the University of Geneva.KJG.and A.R.F.acknowledge support from DST-DAAD project INT/FRG/DAAD/P-07/2018.
文摘Nitric oxide(NO)has emerged as an important signal molecule in plants,having myriad roles in plant devel-opment.In addition,NO also orchestrates both biotic and abiotic stress responses,during which intensive cellular metabolic reprogramming occurs.Integral to these responses is the location of NO biosynthetic and scavenging pathways in diverse cellular compartments,enabling plants to effectively organize signal transduction pathways.NO regulates plant metabolism and,in turn,metabolic pathways reciprocally regu-late NO accumulation and function.Thus,these diverse cellular processes are inextricably linked.This re-view addresses the numerous redox pathways,located in the various subcellular compartments that pro-duce NO,in addition to the mechanisms underpinning NO scavenging.We focus on how this molecular dance is integrated into the metabolic state of the cell.Within this context,a reciprocal relationship be-tween NO accumulation and metabolite production is often apparent.We also showcase cellular pathways,including those associated with nitrate reduction,that provide evidence for this integration of NO function and metabolism.Finally,we discuss the potential importance of the biochemical reactions governing NO levels in determining plant responses to a changing environment.
基金supported by a grant from the National Science Foundation(IOS-1645659)to L.Z.No conflict of interest declared.
文摘Post-translational modifications(PTMs)are central to the modulation of protein activity,stability,subcellular localization,and interaction with partners.They greatly expand the diversity and functionality of the proteome and have taken the center stage as key players in regulating numerous cellular and physiological processes.Increasing evidence indicates that in addition to a single regulatory PTM,many proteins are modified by multiple different types of PTMs in an orchestrated manner to collectively modulate the biological outcome.Such PTM crosstalk creates a combinatorial explosion in the number of proteoforms in a cell and greatly improves the ability of plants to rapidly mount and fine-tune responses to different external and internal cues.While PTM crosstalk has been investigated in depth in humans,animals,and yeast,the study of interplay between different PTMs in plants is still at its infant stage.In the past decade,investigations showed that PTMs are widely involved and play critical roles in the regulation of interactions between plants and pathogens.In particular,ubiquitination has emerged as a key regulator of plant immunity.This review discusses recent studies of the crosstalk between ubiquitination and six other PTMs,i.e.,phosphorylation,SUMOylation,poly(ADP-ribosyl)ation,acetylation,redox modification,and glycosylation,in the regulation of plant immunity.The two basic ways by which PTMs communicate as well as the underlying mechanisms and diverse outcomes of the PTM crosstalk in plant immunity are highlighted.
文摘Cross talk between phytohormones, nitric oxide （NO）, and auxin has been implicated in the control of plant growth and development. Two recent reports indicate that NO promoted auxin signaling but inhibited auxin transport probably through S-nitrosylation. However, genetic evidence for the effect of S-nitrosylation on auxin physiology has been lacking. In this study, we used a genetic approach to understand the broader role of S-nitrosylation in auxin physiology in Arabidopsis. We compared auxin signaling and transport in Col-0 and gsnorl-3, a loss-of-function GSNOR1 mutant defective in protein de-nitrosylation. Our results showed that auxin signaling was impaired in the gsnorl-3 mutant as revealed by significantly reduced DR5-GUS/ DR5-GFP accumulation and compromised degradation of AXR3NT-GUS, a useful reporter in interrogating auxin-mediated degradation of Aux/IAA by auxin receptors. In addition, polar auxin transport was compro- mised in gsnorl-3, which was correlated with universally reduced levels of PIN or GFP-PIN proteins in the roots of the mutant in a manner independent of transcription and 26S proteasome degradation. Our results suggest that S-nitrosylation and GSNORl-mediated de-nitrosylation contribute to auxin physiology, and impaired auxin signaling and compromised auxin transport are responsible for the auxin-related morpho- logical phenotypes displayed by the gsnorl-3 mutant.
