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
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
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
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
Hydrogen sulfide (H_(2)S) is one of the three known gas signal transducers, and since its potential physiological role was reported, the literature on H_(2)S has been increasing. H_(2)S is involved in processes such a...Hydrogen sulfide (H_(2)S) is one of the three known gas signal transducers, and since its potential physiological role was reported, the literature on H_(2)S has been increasing. H_(2)S is involved in processes such as vasodilation, neurotransmission, angiogenesis, inflammation, and the prevention of ischemia-reperfusion injury, and its mechanism remains to be further studied. At present, the role of post-translational processing of proteins has been considered as a possible mechanism for the involvement of H_(2)S in a variety of physiological processes. Current studies have shown that H_(2)S is involved in S-sulfhydration, phosphorylation, and S-nitrosylation of proteins, etc. This paper focuses on the effects of protein modification involving H_(2)S on physiological and pathological processes, looking forward to providing guidance for subsequent research.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
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
Nitric oxide(NO)is a short-lived gaseous free radical that predominantly functions as a messenger and effector molecule.It affects a variety of physiological processes,including programmed cell death(PCD)through cycli...Nitric oxide(NO)is a short-lived gaseous free radical that predominantly functions as a messenger and effector molecule.It affects a variety of physiological processes,including programmed cell death(PCD)through cyclic guanosine monophosphate(cGMP)-dependent and-independent pathways.In this field,dominant discoveries are the diverse apoptosis networks in mammalian cells,which involve signals primarily via death receptors(extrinsic pathway)or the mitochondria(intrinsic pathway)that recruit caspases as effector molecules.In plants,PCD shares some similarities with animal cells,but NO is involved in PCD induction via interacting with pathways of phytohormones.NO has both promoting and suppressing effects on cell death,depending on a variety of factors,such as cell type,cellular redox status,and the flux and dose of local NO.In this article,we focus on how NO regulates the apoptotic signal cascade through protein S-nitrosylation and review the recent progress on mechanisms of PCD in both mammalian and plant cells.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
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
S-Nitros(yl)ation is a ubiquitous redox-based post-translational modification of protein cysteine thiols by nitric oxide or its derivatives,which transduces the bioactivity of nitric oxide(NO)by regulation of protein ...S-Nitros(yl)ation is a ubiquitous redox-based post-translational modification of protein cysteine thiols by nitric oxide or its derivatives,which transduces the bioactivity of nitric oxide(NO)by regulation of protein conformation,activity,stability,localization and pro-tein-protein interactions.These years,more and more S-nitrosated proteins were identified in physiological and pathological processes and the number is still growing.Here we developed a database named SNO-base(http://www.nitrosation.org),which collected S-nitrosation targets extracted from literatures up to June 1st,2012.SNObase contained 2561 instances,and provided information about S-nitrosation targets,sites,biological model,related diseases,trends of S-nitrosation level and effects of S-nitrosation on protein function.With SNObase,we did functional analysis for all the SNO targets:In the gene ontology(GO)biological process category,some processes were discovered to be related to S-nitrosation(“response to drug”,“regulation of cell motion”)besides the previously reported related processes.In the GO cellular component category,cytosol and mitochondrion were both enriched.From the KEGG pathway enrichment results,we found SNO targets were enriched in different diseases,which suggests possible significant roles of S-nitrosation in the progress of these diseases.This SNObase means to be a database with precise,comprehensive and easily accessible information,an environment to help researchers integrate data with comparison and relevancy analysis between different groups or works,and also an SNO knowledgebase offering feasibility for systemic and global analysis of S-nitrosation in interdisciplinary studies.展开更多
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.
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.
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(No.81802718 and 81670088)the Training Program for Young Backbone Teachers of Institutions of Higher Learning in Henan Province,China(No.2020GGJS038)the Foundation of Science&Technology Department of Henan Province,China(No.202102310480,222102310490,and 222102310495).
文摘Hydrogen sulfide (H_(2)S) is one of the three known gas signal transducers, and since its potential physiological role was reported, the literature on H_(2)S has been increasing. H_(2)S is involved in processes such as vasodilation, neurotransmission, angiogenesis, inflammation, and the prevention of ischemia-reperfusion injury, and its mechanism remains to be further studied. At present, the role of post-translational processing of proteins has been considered as a possible mechanism for the involvement of H_(2)S in a variety of physiological processes. Current studies have shown that H_(2)S is involved in S-sulfhydration, phosphorylation, and S-nitrosylation of proteins, etc. This paper focuses on the effects of protein modification involving H_(2)S on physiological and pathological processes, looking forward to providing guidance for subsequent research.
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.
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This work was supported by funding from the National Natural Science Foundation of China(Grant Nos.30600407,30825029)an international exchange grant provided by the National Natural Science Foundation of China and the Royal Society of Edinburgh.
文摘Nitric oxide(NO)is a short-lived gaseous free radical that predominantly functions as a messenger and effector molecule.It affects a variety of physiological processes,including programmed cell death(PCD)through cyclic guanosine monophosphate(cGMP)-dependent and-independent pathways.In this field,dominant discoveries are the diverse apoptosis networks in mammalian cells,which involve signals primarily via death receptors(extrinsic pathway)or the mitochondria(intrinsic pathway)that recruit caspases as effector molecules.In plants,PCD shares some similarities with animal cells,but NO is involved in PCD induction via interacting with pathways of phytohormones.NO has both promoting and suppressing effects on cell death,depending on a variety of factors,such as cell type,cellular redox status,and the flux and dose of local NO.In this article,we focus on how NO regulates the apoptotic signal cascade through protein S-nitrosylation and review the recent progress on mechanisms of PCD in both mammalian and plant cells.
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.
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 the National Basic Research Program of China(973 Program)(Nos.2011CB910900,2012CB911000,2011CB503900)the National Natural Sciences Foundation of China(Grant No.31030023)the Knowledge Innovation Program of the Chinese Academy of Sciences.
文摘S-Nitros(yl)ation is a ubiquitous redox-based post-translational modification of protein cysteine thiols by nitric oxide or its derivatives,which transduces the bioactivity of nitric oxide(NO)by regulation of protein conformation,activity,stability,localization and pro-tein-protein interactions.These years,more and more S-nitrosated proteins were identified in physiological and pathological processes and the number is still growing.Here we developed a database named SNO-base(http://www.nitrosation.org),which collected S-nitrosation targets extracted from literatures up to June 1st,2012.SNObase contained 2561 instances,and provided information about S-nitrosation targets,sites,biological model,related diseases,trends of S-nitrosation level and effects of S-nitrosation on protein function.With SNObase,we did functional analysis for all the SNO targets:In the gene ontology(GO)biological process category,some processes were discovered to be related to S-nitrosation(“response to drug”,“regulation of cell motion”)besides the previously reported related processes.In the GO cellular component category,cytosol and mitochondrion were both enriched.From the KEGG pathway enrichment results,we found SNO targets were enriched in different diseases,which suggests possible significant roles of S-nitrosation in the progress of these diseases.This SNObase means to be a database with precise,comprehensive and easily accessible information,an environment to help researchers integrate data with comparison and relevancy analysis between different groups or works,and also an SNO knowledgebase offering feasibility for systemic and global analysis of S-nitrosation in interdisciplinary studies.