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1.
Arginine methylation constitutes a posttranslational modification dependent on the action of protein arginine methyltransferases (PRMTs). Using S-adenosylmethionine as a methyl donor, PRMTs catalyze the formation of monomethylarginine (L-NMMA), asymmetric dimethylarginine (ADMA), or symmetric dimethylarginine (SDMA). Protein arginine methylation is involved in the regulation of signal transduction, RNA export, and cell proliferation, but a quantitative view of arginine methylation of the cell and tissue proteome remains to be performed. In this study, we developed a high-performance liquid chromatography (HPLC)-based method to accurately quantify methylated arginines in free and protein-incorporated amino acid pools of cell and tissue extracts, using protein precipitation and hydrolysis, HPLC separation, and fluorescence detection for the simultaneous quantification of L-arginine (L-Arg), L-NMMA, ADMA, and SDMA. This method permits accurate assessment of the degree of protein arginine methylation in complex biological samples. Using this method, we determined dynamic changes in protein methylation in vitro in cells subjected to proteasome inhibition. We furthermore demonstrate differential methylation patterns in heart and kidney lysates in vivo. Thus, the described method will greatly facilitate our understanding of the role of arginine methylation in physiology and pathophysiology and of the effects of pharmacological interventions on arginine methylation in select cell culture models.  相似文献   

2.
3.
Arginine methylation is a common posttranslational modification (PTM) that alters roughly 0.5% of all arginine residues in the cells. There are three types of arginine methylation: monomethylarginine (MMA), asymmetric dimethylarginine (ADMA), and symmetric dimethylarginine (SDMA). These three PTMs are enriched on RNA-binding proteins and on histones, and also impact signal transduction cascades. To date, over thirty arginine methylation sites have been cataloged on the different core histones. These modifications alter protein structure, impact interactions with DNA, and also generate docking sites for effector molecules. The primary “readers” of methylarginine marks are Tudor domain-containing proteins. The complete family of thirty-six Tudor domain-containing proteins has yet to be fully characterized, but at least ten bind methyllysine motifs and eight bind methylarginine motifs. In this review, we will highlight the biological roles of the Tudor domains that interact with arginine methylated motifs, and also address other types of interactions that are regulated by these particular PTMs. This article is part of a Special Issue entitled: Molecular mechanisms of histone modification function.  相似文献   

4.
N(G), N(G)-Dimethyl-L-arginine (asymmetric dimethylarginine: ADMA) is an endogenous competitive inhibitor of nitric oxide synthase (NOS). Plasma ADMA concentrations have been reported to increase in connection with diseases associated with an impaired endothelial L-arginine/NO pathway. In this study, we investigated the metabolism of ADMA in circulating blood cell populations to elucidate the regulatory mechanism of elevation of plasma ADMA, a novel risk factor for cardiovascular disease. We found by RT-PCR and Western blot analyses that protein arginine methyltransferase (PRMT)1 and dimethylarginine dimethylaminohydrolase (DDAH)-1, responsible for the biosynthesis and degradation of ADMA respectively, are expressed in erythrocytes (ECs), leukocytes, and platelets. We also identified a major ADMA-containing protein in ECs as catalase, confirmed by GST-pull down assay to bind to PRMT1 in vitro. This is the first report that the ADMA-metabolizing system, including the arginine methylation of proteins and the breakdown of free ADMA, occurs in circulating blood cell-populations, and that catalase in ECs might be a potential protein targeted by PRMT1.  相似文献   

5.
The enzyme dimethylarginine dimethylaminohydrolase (DDAH) is responsible for the hydrolysis of asymmetric dimethylarginine (ADMA) to L-citrulline and dimethylamine. DDAH is currently investigated as a promising target for therapeutic interventions, as ADMA has been found to be elevated in cardiovascular disease. In many tissues continuous endogenous formation of ADMA and L-citrulline poses considerable limitations to the presently used assays for DDAH activity, which are commonly based on the measurement of ADMA or L-citrulline. We therefore developed a stable-isotope-based assay suitable for 96-well plates to determine DDAH activity. Using deuterium-labeled ADMA ([(2)H(6)]-ADMA) as substrate and double stable-isotope labeled ADMA ([(13)C(5)-(2)H(6)]-ADMA) as internal standard we were able to simultaneously determine formation and metabolism of ADMA in renal and liver tissue of mice by LC-tandem MS. Endogenous formation of ADMA could largely be abolished by addition of protease inhibitors, while metabolism of [(2)H(6)]-ADMA was not significantly altered. The intra-assay coefficient of variation for the determination of endogenous ADMA and [(2)H(6)]-ADMA was 2.4% and 4.8% in renal and liver tissue, respectively. The inter-assay coefficient of variation for DDAH activity based on degradation of [(2)H(6)]-ADMA determined in separate samples from the same organs was determined to be 8.9% and 10% for mouse kidney and liver, respectively. The present DDAH activity assay allows for the first time to simultaneously determine DDAH activity and endogenous formation of ADMA, SDMA, and L-arginine in tissue.  相似文献   

6.
We have identified a protein, FLJ12673 or FBXO11, that contains domains characteristically present in protein arginine methyltransferases (PRMTs). Immuno-purified protein expressed from one of the four splice variants in HeLa cells and in Escherichia coli exhibited methyltransferase activity. Monomethylarginine, symmetric, and asymmetric dimethylarginine (SDMA, ADMA) were formed on arginine residues. Accordingly, we have designated the protein PRMT9. PRMT9 is the third member of the PRMT family that forms SDMA modifications in proteins. Structurally, this protein is distinct from all other known PRMTs implying that convergent evolution allowed this protein to develop the ability to methylate arginine residues and evolved elements conserved in PRMTs to accomplish this.  相似文献   

7.
N G,N G-Dimethyl-L-arginine (asymmetric dimethylarginine: ADMA) is an endogenous competitive inhibitor of nitric oxide synthase (NOS). Plasma ADMA concentrations have been reported to increase in connection with diseases associated with an impaired endothelial L-arginine/NO pathway. In this study, we investigated the metabolism of ADMA in circulating blood cell populations to elucidate the regulatory mechanism of elevation of plasma ADMA, a novel risk factor for cardiovascular disease. We found by RT-PCR and Western blot analyses that protein arginine methyltransferase (PRMT)1 and dimethylarginine dimethylaminohydrolase (DDAH)-1, responsible for the biosynthesis and degradation of ADMA respectively, are expressed in erythrocytes (ECs), leukocytes, and platelets. We also identified a major ADMA-containing protein in ECs as catalase, confirmed by GST-pull down assay to bind to PRMT1 in vitro. This is the first report that the ADMA-metabolizing system, including the arginine methylation of proteins and the breakdown of free ADMA, occurs in circulating blood cell-populations, and that catalase in ECs might be a potential protein targeted by PRMT1.  相似文献   

8.
Protein arginine methyltransferases (PRMTs) catalyze the post-translational methylation of specific arginyl groups within targeted proteins to regulate fundamental biological responses in eukaryotic cells. The major Type I PRMT enzyme, PRMT1, strictly generates monomethyl arginine (MMA) and asymmetric dimethylarginine (ADMA), but not symmetric dimethylarginine (SDMA). Multiple diseases can arise from the dysregulation of PRMT1, including heart disease and cancer, which underscores the need to elucidate the origin of product specificity. Molecular dynamics (MD) simulations were carried out for WT PRMT1 and its M48F, H293A, H293S, and H293S-M48F mutants bound with S-adenosylmethionine (AdoMet) and the arginine substrate in an unmethylated or methylated form. Experimental site-directed mutagenesis and analysis of the resultant products were also performed. Two specific PRMT1 active site residues, Met48 and His293, have been determined to play a key role in dictating product specificity, as: (1) the single mutation of Met48 to Phe enabled PRMT1 to generate MMA, ADMA, and a limited amount of SDMA; (2) the single mutation of His293 to Ser formed the expected MMA and ADMA products only; whereas (3) the double mutant H293S-M48F-PRMT1 produced SMDA as the major product with limited amounts of MMA and ADMA. Calculating the formation of near-attack conformers resembling SN2 transition states leading to either the ADMA or SDMA products finds that Met48 and His293 may enable WT PRMT1 to yield ADMA exclusively by precluding MMA from binding in an orientation more conducive to SDMA formation, i.e., the methyl group bound at the arginine Nη2 position.  相似文献   

9.
Nitric oxide (NO) has been suggested to play a key role in the pathogenesis of pulmonary hypertension (PH). To determine which mechanism exists to affect NO production, we examined the concentration of endogenous nitric oxide synthase (NOS) inhibitors and their catabolizing enzyme dimethylarginine dimethylaminohydrolase (DDAH) activity and protein expression (DDAH1 and DDAH2) in pulmonary artery endothelial cells (PAECs) of rats given monocrotaline (MCT). We also measured NOS and arginase activities and NOS protein expression. Twenty-four days after MCT administration, PH and right ventricle (RV) hypertrophy were established. Endothelium-dependent, but not endothelium-independent, relaxation and cGMP production were significantly impaired in pulmonary artery specimens of MCT group. The constitutive NOS activity and protein expression in PAECs were significantly reduced in MCT group, whereas the arginase, which shares l-arginine as a common substrate with NOS, activity was significantly enhanced in PAECs of MCT group. The contents of monomethylarginine (MMA) and asymmetric dimethylarginine (ADMA), but not symmetric dimethylarginine (SDMA), were increased in PAECs of MCT group. The DDAH activity and DDAH1, but not DDAH2, protein expression were significantly reduced in PAECs of MCT group. These results suggest that the impairment of cGMP production as a marker of NO production is possibly due to the blunted endothelial NOS activity resulting from the downregulation of endothelial NOS protein, accumulation of endogenous NOS inhibitors, and accelerated arginase activity in PAECs of PH rats. The decreased overall DDAH activity accompanied by the downregulation of DDAH1 would bring about the accumulation of endogenous NOS inhibitors.  相似文献   

10.
Elevated levels of asymmetric dimethylarginine (ADMA) correlate with risk factors for cardiovascular disease. ADMA is generated by the catabolism of proteins methylated on arginine residues by protein arginine methyltransferases (PRMTs) and is degraded by dimethylarginine dimethylaminohydrolase. Reports have shown that dimethylarginine dimethylaminohydrolase activity is down-regulated and PRMT1 protein expression is up-regulated under oxidative stress conditions, leading many to conclude that ADMA accumulation occurs via increased synthesis by PRMTs and decreased degradation. However, we now report that the methyltransferase activity of PRMT1, the major PRMT isoform in humans, is impaired under oxidative conditions. Oxidized PRMT1 displays decreased activity, which can be rescued by reduction. This oxidation event involves one or more cysteine residues that become oxidized to sulfenic acid (-SOH). We demonstrate a hydrogen peroxide concentration-dependent inhibition of PRMT1 activity that is readily reversed under physiological H2O2 concentrations. Our results challenge the unilateral view that increased PRMT1 expression necessarily results in increased ADMA synthesis and demonstrate that enzymatic activity can be regulated in a redox-sensitive manner.  相似文献   

11.
Accumulation of S-adenosylhomocysteine (AdoHcy), the homocysteine (Hcy) precursor and a potent methyltransferase inhibitor, may mediate the neurological and vascular complications associated with elevated Hcy. Protein arginine methylation is a crucial post-translational modification and generates monomethylarginine (MMA) and dimethylarginine (asymmetric, ADMA, and symmetric, SDMA) residues. We aimed at determining whether protein arginine methylation status is disturbed in an animal model of diet-induced hyperhomocysteinemia (HHcy). HHcy was achieved by dietary manipulation of Wistar rats: methionine-enrichment (HM), B vitamins deficiency (LV), or both (HMLV). Total Hcy, S-adenosylmethionine (AdoMet), AdoHcy, MMA, ADMA and SDMA concentrations in plasma or tissues (heart, brain and liver) were determined by adequate high-performance liquid chromatography or liquid chromatography-electrospray ionization-tandem mass spectrometry methods. Moreover, in tissues from the HMLV group, histone arginine asymmetric dimethylation was evaluated by Western blotting, and the histone methylation marks H3R17me2a, H3R8me2a and H4R3me2a were studied. HHcy was induced by all special diets, with elevation of AdoHcy concentrations in liver (LV and HMLV) and heart (HMLV) (all versus control). Plasma ADMA levels were lower in all hyperhomocysteinemic animals. Protein-incorporated ADMA levels were decreased in brain and in heart (both for the LV and HMLV groups). Moreover, in brain of animals exposed to the HMLV diet, the H3R8me2a mark was profoundly decreased. In conclusion, our results show that diet-induced Hcy elevation disturbs global protein arginine methylation in a tissue-specific manner and affects histone arginine methylation in brain. Future research is warranted to disclose the functional implications of the global protein and histone arginine hypomethylation triggered by Hcy elevation.  相似文献   

12.
Endogenously produced nitric oxide synthase inhibitor, asymmetric methylarginine (ADMA) is associated with vascular dysfunction and endothelial leakage. We studied the role of ADMA, and the enzymes metabolizing it, dimethylarginine dimethylaminohydrolases (DDAH) in the regulation of endothelial barrier function in pulmonary macrovascular and microvascular cells in vitro and in lungs of genetically modified heterozygous DDAHI knockout mice in vivo. We show that ADMA increases pulmonary endothelial permeability in vitro and in in vivo and that this effect is mediated by nitric oxide (NO) acting via protein kinase G (PKG) and independent of reactive oxygen species formation. ADMA-induced remodeling of actin cytoskeleton and intercellular adherens junctions results from a decrease in PKG-mediated phosphorylation of vasodilator-stimulated phosphoprotein (VASP) and a subsequent down-regulation of Rac1 activity. The effects of ADMA on endothelial permeability, Rac1 activation and VASP phosphorylation are prevented by overexpression of active DDAHI and DDAHII, whereas inactive DDAH mutants have no effect. These findings demonstrate for the first time that ADMA metabolism critically determines pulmonary endothelial barrier function by modulating Rac1-mediated remodeling of the actin cytoskeleton and intercellular junctions.  相似文献   

13.
Asymmetric dimethylarginine (ADMA), an endogenous inhibitor of nitric oxide (NO) synthase, has been proposed to be a mediator of vascular dysfunction during hyperhomocysteinemia. Levels of ADMA are regulated by dimethylarginine dimethylaminohydrolase (DDAH). Using both in vitro and in vivo approaches, we tested the hypothesis that hyperhomocysteinemia causes downregulation of the two genes encoding DDAH (Ddah1 and Ddah2). In the MS-1 murine endothelial cell line, the addition of homocysteine decreased NO production but did not elevate ADMA or alter levels of Ddah1 or Ddah2 mRNA. Mice heterozygous for cystathionine beta-synthase (Cbs) and their wild-type littermates were fed either a control diet or a high-methionine/low-folate (HM/LF) diet to produce varying degrees of hyperhomocysteinemia. Maximal relaxation of the carotid artery to the endothelium-dependent dilator acetylcholine was decreased by approximately 50% in Cbs(+/-) mice fed the HM/LF diet compared with Cbs(+/+) mice fed the control diet (P < 0.001). Compared with control mice, hyperhomocysteinemic mice had lower levels of Ddah1 mRNA in the liver (P < 0.001) and lower levels of Ddah2 mRNA in the liver, lung, and kidney (P < 0.05). Downregulation of DDAH expression in hyperhomocysteinemic mice did not result in an increase in plasma ADMA, possibly due to a large decrease in hepatic methylation capacity (S-adenosylmethionine-to-S-adenosylhomocysteine ratio). Our findings demonstrate that hyperhomocysteinemia causes tissue-specific decreases in DDAH expression without altering plasma ADMA levels in mice with endothelial dysfunction.  相似文献   

14.
《Bioscience Hypotheses》2008,1(3):145-146
Hepatorenal syndrome (HRS) is a major complication of cholestatic liver disease (CLD), characterized by vasoconstriction. Since nitric oxide (NO) is a potent vasodilator, NO deficiency has been proposed to cause HRS. Retention of bile acid plays a role in liver damage; however, whether bile acid triggers extrahepatic tissue damage is unclear. Farnesoid X receptor (FXR) is a bile acid-sensor nuclear receptor abundant in the kidney. We recently found increased oxidative stress and asymmetric dimethylarginine (ADMA) are major causes of NO deficiency. We hypothesize that impaired regulation of FXR and its target genes by bile acid within the kidney resulting in HRS through two major mechanisms: First, increased oxidative stress due to decreased glutathione/reduced glutathione ratio, which is regulated by FXR-target genes, multidrug resistance-associated proteins (MRPs); Second, increased ADMA due to impaired regulation of protein arginine methyltransferase (PRMT, ADMA-synthesizing enzyme) 1 and dimethylarginine dimethylaminohydrolase (DDAH, ADMA-metabolizing enzyme) by FXR. Therefore, FXR agonist may be a therapeutic approach to treat HRS via reducing oxidative stress and ADMA to restore NO in CLD.  相似文献   

15.
Asymmetric (N(G),N(G))-dimethylarginine (ADMA) inhibits nitric oxide (NO) synthases (NOS). ADMA is a risk factor for endothelial dysfunction, cardiovascular mortality, and progression of chronic kidney disease. Two isoforms of dimethylarginine dimethylaminohydrolase (DDAH) metabolize ADMA. DDAH-1 is the predominant isoform in the proximal tubules of the kidney and in the liver. These organs extract ADMA from the circulation. DDAH-2 is the predominant isoform in the vasculature, where it is found in endothelial cells adjacent to the cell membrane and in intracellular vesicles and in vascular smooth muscle cells among the myofibrils and the nuclear envelope. In vivo gene silencing of DDAH-1 in the rat and DDAH +/- mice both have increased circulating ADMA, whereas gene silencing of DDAH-2 reduces vascular NO generation and endothelium-derived relaxation factor responses. DDAH-2 also is expressed in the kidney in the macula densa and distal nephron. Angiotensin type 1 receptor activation in kidneys reduces the expression of DDAH-1 but increases the expression of DDAH-2. This rapidly evolving evidence of isoform-specific distribution and regulation of DDAH expression in the kidney and blood vessels provides potential mechanisms for nephron site-specific regulation of NO production. In this review, the recent advances in the regulation and function of DDAH enzymes, their roles in the regulation of NO generation, and their possible contribution to endothelial dysfunction in patients with cardiovascular and kidney diseases are discussed.  相似文献   

16.
The balance between nitric oxide (NO) and vasoconstrictors like endothelin is essential for vascular tone and endothelial function. L-Arginine is converted to NO and L-citrulline by NO synthase (NOS). Asymmetric dimethylarginine (ADMA) and symmetric dimethylarginine (SDMA) are endogenous inhibitors of NO formation. ADMA is degraded by dimethylamino dimethylhydrolases (DDAHs), while SDMA is exclusively eliminated by the kidney. In the present article we report a LC-tandem MS method for the simultaneous determination of arginine, ADMA, and SDMA in plasma. This method is designed for high sample throughput of only 20-mul aliquots of human or mouse plasma. The analysis time is reduced to 1.6 min by LC-tandem MS electrospray ionisation (ESI) in the positive mode. The mean plasma levels of l-arginine, ADMA, and SDMA were 74+/-19 (SD), 0.46+/-0.09, and 0.37+/-0.07 microM in healthy humans (n=85), respectively, and 44+/-14, 0.72+/-0.23, and 0.19+/-0.06 microM in C57BL/6 mice. Also, the molar ratios of arginine to ADMA were different in man and mice, i.e. 166+/-50 and 85+/-22, respectively.  相似文献   

17.
Asymmetric dimethylarginine (ADMA) is an endogenous inhibitor of nitric oxide synthase and is metabolised by dimethylarginine dimethylaminohydrolase (DDAH). Elevated levels of circulating ADMA correlate with various cardiovascular pathologies less is known about the cellular effects of altered DDAH activity. We modified DDAH activity in cells and measured the changes in ADMA levels, morphological phenotypes on Matrigel, and expression of vascular endothelial growth factor (VEGF). DDAH over-expressing ECV304 cells secreted less ADMA and when grown on Matrigel had enhanced tube formation compared to untransfected cells. VEGF mRNA levels were 2.1-fold higher in both ECV304 and murine endothelial cells (sEnd.1) over-expressing DDAH. In addition the DDAH inhibitor, S-2-amino-4(3-methylguanidino)butanoic acid (4124W 1mM), markedly reduced human umbilical vein endothelial cell tube formation in vitro. We have found that upregulating DDAH activity lowers ADMA levels, increases the levels of VEGF mRNA in endothelial cells, and enhances tube formation in an in vitro model, whilst blockade of DDAH reduces tube formation.  相似文献   

18.
Human protein arginine methyltransferase (PRMT) 9 symmetrically dimethylates arginine residues on splicing factor SF3B2 (SAP145) and has been functionally linked to the regulation of alternative splicing of pre-mRNA. Site-directed mutagenesis studies on this enzyme and its substrate had revealed essential unique residues in the double E loop and the importance of the C-terminal duplicated methyltransferase domain. In contrast to what had been observed with other PRMTs and their physiological substrates, a peptide containing the methylatable Arg-508 of SF3B2 was not recognized by PRMT9 in vitro. Although amino acid substitutions of residues surrounding Arg-508 had no great effect on PRMT9 recognition of SF3B2, moving the arginine residue within this sequence abolished methylation. PRMT9 and PRMT5 are the only known mammalian enzymes capable of forming symmetric dimethylarginine (SDMA) residues as type II PRMTs. We demonstrate here that the specificity of these enzymes for their substrates is distinct and not redundant. The loss of PRMT5 activity in mouse embryo fibroblasts results in almost complete loss of SDMA, suggesting that PRMT5 is the primary SDMA-forming enzyme in these cells. PRMT9, with its duplicated methyltransferase domain and conserved sequence in the double E loop, appears to have a unique structure and specificity among PRMTs for methylating SF3B2 and potentially other polypeptides.  相似文献   

19.
Post-translational methylation of arginine residues in proteins leads to generation of N(G)-monomethylarginine (MMA) and both symmetric and asymmetric dimethylarginine (SDMA and ADMA), that are released into the cytosol upon proteolysis. Both MMA and ADMA are inhibitors of nitric oxide synthase and especially elevated levels of ADMA are associated with endothelial dysfunction and cardiovascular disease. Plasma concentrations of ADMA and SDMA are very low, typically between 0.3 and 0.8 microM, making their quantification by HPLC an analytical challenge. Sample preparation usually involves a cleanup step by solid-phase extraction on cation-exchange columns followed by derivatization of amino acids into fluorescent adducts. Because ADMA and SDMA concentrations in healthy subjects show a very narrow distribution, with a between-subject variability of 13% for ADMA and 19% for SDMA, very low imprecision is an essential assay feature. Procedures for sample cleanup, derivatization, and chromatographic separation of arginine and its methylated analogs are the main topics of this review. In addition, important aspects of method validation, pre-analytical factors, and reference values are discussed.  相似文献   

20.
To investigate the effect of three red wines (RWs) from different growing areas and made from different grapes on asymmetric dimethylarginine (ADMA), an endogenous inhibitor of nitric oxide synthase, in young and senescent human endothelial cells (ECs). All RWs decreased ADMA levels, but 2-fold concentration of German RW was necessary to reach the same effect on ADMA compared to Italian RW and French RW without affecting the cell viability and morphology. The ADMA-lowering effect of RW was increased in senescent compared to young cells, accompanied by enhanced activity of the metabolizing enzyme: dimethylarginine dimethylaminohydrolase (DDAH) II, whereas the same amount in the upregulated protein expression of DDAH II and the downregulated protein expression of the synthesizing enzyme: protein arginine methyltransferase 1 was revealed. These effects were associated with decreased 8-iso-prostaglandin F and peroxynitrite formation, enhanced protein expression of NAD+-dependent class III histone deacetylase sirtuin (SIRT) 1, and downregulated protein expression of histone senescence factor p53. Blockade of SIRT1 activity abolished the effect of red wine on ADMA. These data are the first demonstration that RW by activating SIRT1 impairs synthesis and increases metabolism of ADMA. This effect of RW is accentuated in senescent cells probably due to enhanced DDAH activity.  相似文献   

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