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Sang-gyu Park - One of the best experts on this subject based on the ideXlab platform.
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serum aminoacyl trna synthetase interacting Multifunctional Protein 1 aimp1 a novel disease activity predictive biomarker of systemic lupus erythematosus
Clinical and Experimental Rheumatology, 2018Co-Authors: Shin Hee Hong, Younhee Park, Seung Min Jung, Jason Jungsik Song, Yongbeom Park, Sang-gyu ParkAbstract:OBJECTIVES: Secreted aminoacyl-tRNA synthetase-interacting Multifunctional Protein-1 (AIMP1) has been reported to have pro-inflammatory properties. The aim of this study was to evaluate the clinical significance of serum AIMP1 in patients with systemic lupus erythematosus (SLE). METHODS: Serum levels of AIMP1 were measured in 160 patients with SLE using a human AIMP1 ELISA kit. Eighty patients were classified as active SLE (SLEDAI-2K ≥ 5), and 80 patients were classified as stable SLE. Correlation between serum AIMP1, SLE disease activity index-2000 (SLEDAI-2K), and laboratory variables related to disease activity or inflammatory burdens were assessed using Pearson's correlation analysis. The optimal cut-off value for serum AIMP1 to predict active SLE was estimated by using a receiver operator characteristic curve, and logistic regression analysis was used to compare the odds ratios (ORs) of laboratory variables in predicting active SLE. RESULTS: The median serum AIMP1 was higher in patients with active SLE than those with stable SLE (8.0 vs. 6.5 ng/ml, p<0.001). Serum AIMP1 demonstrated correlation with SLEDAI-2K and laboratory variables related to disease activity or inflammatory burdens. The optimal cut-off AIMP1 to predict active SLE was 10.09. Multivariate logistic regression analysis including conventional laboratory variables demonstrated that serum AIMP1 ≥10.09 ng/ml (OR 3.919, 95% confidence interval 1.223-12.564, p=0.022) was useful in predicting active SLE. CONCLUSIONS: Serum levels of AIMP1 were associated with disease activity of SLE and could predict active SLE based on SLEDAI-2K.
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serum aminoacyl trna synthetase interacting Multifunctional Protein 1 aimp1 a novel disease activity predictive biomarker of systemic lupus erythematosus
Clinical and Experimental Rheumatology, 2018Co-Authors: Shin Hee Hong, Younhee Park, Seung Min Jung, Jason Jungsik Song, Yongbeom Park, Sang-gyu ParkAbstract:OBJECTIVES: Secreted aminoacyl-tRNA synthetase-interacting Multifunctional Protein-1 (AIMP1) has been reported to have pro-inflammatory properties. The aim of this study was to evaluate the clinical significance of serum AIMP1 in patients with systemic lupus erythematosus (SLE). METHODS: Serum levels of AIMP1 were measured in 160 patients with SLE using a human AIMP1 ELISA kit. Eighty patients were classified as active SLE (SLEDAI-2K ≥ 5), and 80 patients were classified as stable SLE. Correlation between serum AIMP1, SLE disease activity index-2000 (SLEDAI-2K), and laboratory variables related to disease activity or inflammatory burdens were assessed using Pearson's correlation analysis. The optimal cut-off value for serum AIMP1 to predict active SLE was estimated by using a receiver operator characteristic curve, and logistic regression analysis was used to compare the odds ratios (ORs) of laboratory variables in predicting active SLE. RESULTS: The median serum AIMP1 was higher in patients with active SLE than those with stable SLE (8.0 vs. 6.5 ng/ml, p<0.001). Serum AIMP1 demonstrated correlation with SLEDAI-2K and laboratory variables related to disease activity or inflammatory burdens. The optimal cut-off AIMP1 to predict active SLE was 10.09. Multivariate logistic regression analysis including conventional laboratory variables demonstrated that serum AIMP1 ≥10.09 ng/ml (OR 3.919, 95% confidence interval 1.223-12.564, p=0.022) was useful in predicting active SLE. CONCLUSIONS: Serum levels of AIMP1 were associated with disease activity of SLE and could predict active SLE based on SLEDAI-2K.
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aminoacyl trna synthetase interacting Multifunctional Protein 1 p43 controls endoplasmic reticulum retention of heat shock Protein gp96 its pathological implications in lupus like autoimmune diseases
American Journal of Pathology, 2007Co-Authors: Sang-gyu Park, Bumjoon Park, Yeong Wook Song, Zihai LiAbstract:Aminoacyl-tRNA synthetase-interacting Multifunctional Protein 1 (AIMP1; previously known as p43) is a Multifunctional Protein that was initially found in multitRNA synthetase complex. In the present study, screening of the AIMP1-binding Proteins revealed that AIMP1 can form a molecular complex with heat shock Protein gp96. AIMP1 enhances gp96 dimerization and the interaction between gp96 and KDEL receptor-1 (KDELR-1), which mediates the retrieval of KDEL-containing Proteins from Golgi to the endoplasmic reticulum (ER). The interaction between gp96 and KDELR-1 was reduced in AIMP1-deficient cells, and this disturbed ER retention of gp96 and increased its cell surface localization. Moreover, this localization of gp96 at the cell surface was suppressed by its interaction with AIMP1 and enhanced by the depletion of endogenous AIMP1. In addition, AIMP1-deficient mice showed dendritic cell activation attributable to increased gp96 surface presentation and lupus-like autoimmune phenotypes. These results suggest that AIMP1 acts as a regulator of the ER retention of gp96 and provide a new perspective of the regulatory mechanism underlying immune stimulation by gp96.
David R Evans - One of the best experts on this subject based on the ideXlab platform.
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Protein kinase a phosphorylation of the Multifunctional Protein cad antagonizes activation by the map kinase cascade
Molecular and Cellular Biochemistry, 2007Co-Authors: Damian H Kotsis, Frederic Sigoillot, Elizabeth Masko, Roberto Di Gregorio, Hedeel Guyevans, David R EvansAbstract:The flux through the de novo pyrimidine biosynthetic pathway is controlled by the Multifunctional Protein CAD, which catalyzes the first three steps. The cell cycle dependent regulation of pyrimidine biosynthesis is a consequence of sequential phosphorylation of CAD Thr456 and Ser1406 by the MAP kinase and PKA cascades, respectively. Coordinated regulation of the pathway requires precise timing of the two phosphorylation events. These studies show that phosphorylation of purified CAD by PKA antagonizes MAP kinase phosphorylation, and vice versa. Similar results were observed in vivo. Forskolin activation of PKA in BHK-21 cells resulted in a 8.5 fold increase in Ser1406 phosphorylation and severely curtailed the MAP kinase mediated phosphorylation of CAD Thr456. Moreover, the relative activity of MAP kinase and PKA was found to determine the extent of Thr456 phosphorylation. Transfectants expressing elevated levels of MAP kinase resulted in a 11-fold increase in Thr456 phosphorylation, whereas transfectants that overexpress PKA reduced Thr456 phosphorylation 5-fold. While phosphorylation of one site by one kinase may induce conformational changes that interfere with phosphorylation by the other, the observation that both MAP kinase and PKA form stable complexes with CAD suggest that the mutual antagonism is the result of steric interference by the bound kinases. The reciprocal antagonism of CAD phosphorylation by MAP kinase and PKA provides an elegant mechanism to coordinate the cell cycle-dependent regulation of pyrimidine biosynthesis ensuring that signals for up- and down-regulation of the pathway do not conflict.
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autophosphorylation of the mammalian Multifunctional Protein that initiates de novo pyrimidine biosynthesis
Journal of Biological Chemistry, 2002Co-Authors: Frederic Sigoillot, David R EvansAbstract:Abstract CAD, a large Multifunctional Protein that carries carbamoyl phosphate synthetase (CPSase), aspartate transcarbamoylase, and dihydroorotase activities, catalyzes the first three steps of de novo pyrimidine biosynthesis in mammalian cells. The CPSase component, which catalyzes the initial, rate-limiting step, exhibits complex regulatory mechanisms involving allosteric effectors and phosphorylation that control the flux of metabolites through the pathway. Incubation of CAD with ATP in the absence of exogenous kinases resulted in the incorporation of 1 mol of Pi/mol of CAD monomer. Mass spectrometry analysis of tryptic digests showed that Thr1037 located within the CAD CPS.B subdomain was specifically modified. The reaction is specific for MgATP, ADP was a competitive inhibitor, and the native tertiary structure of the Protein was required. Phosphorylation occurred after denaturation, further purification of CAD by SDS gel electrophoresis, and renaturation on a nitrocellulose membrane, strongly suggesting that phosphate incorporation resulted from an intrinsic kinase activity and was not the result of contaminating kinases. Chemical modification with the ATP analog, 5′-p-fluorosulfonylbenzoyladenosine, showed that one or both of the active sites that catalyze the ATP-dependent partial reactions are also involved in autophosphorylation. The rate of phosphorylation was dependent on the concentration of CAD, indicating that the reaction was, at least in part, intermolecular. Autophosphorylation resulted in a 2-fold increase in CPSase activity, an increased sensitivity to the feedback inhibitor UTP, and decreased allosteric activation by 5-phosphoribosyl-1-pyrophosphate, functional changes that were distinctly different from those resulting from phosphorylation by either the Protein kinase A or mitogen-activated Protein kinase cascades.
Santiago Ramonmaiques - One of the best experts on this subject based on the ideXlab platform.
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cad a Multifunctional Protein leading de novo pyrimidine biosynthesis
eLS, 2017Co-Authors: Maria Morenomorcillo, Santiago RamonmaiquesAbstract:Pyrimidines are essential precursors for DNA (deoxyribonucleic acid) and RNA (ribonucleic acid) synthesis, Protein glycosylation and lipid synthesis. In resting cells, pyrimidines are largely obtained through salvage pathways, but in proliferating cells, particularly in tumours, the synthesis of pyrimidines de novo is indispensable to fuel the high demand of nucleic acids and other cellular components. In animals, the de novo pathway is initiated and controlled by CAD, a ∼240-kDa Multifunctional Protein with four different enzymatic domains: glutaminase (GLN), carbamoyl phosphate synthetase (CPS), dihydroorotase (DHO) and aspartate transcarbamoylase (ATC). In contrast, in bacteria, archaeans and plants, GLN, CPS, DHO and ATC are distinct monofunctional Proteins. The structures of a number of these enzymes from bacteria and archaea are known, but until recently, there was no structural information about CAD other than that it self-assembles into ∼1.5-megaDa hexamers. Key Concepts De novo synthesis of pyrimidine nucleotides is essential for cell growth and proliferation. In animals, the Multifunctional Protein CAD catalyses the first three reactions of de novo pyrimidine synthesis. CAD is a 243-kDa polypeptide with four enzymatic domains [glutaminase (GLN), carbamoyl phosphate synthetase (CPS), dihydroorotase (DHO) and aspartate transcarbamoylase (ATC)] that oligomerises into 1.5-megaDa hexamers. In bacteria, GLN, CPS, DHO and ATC are individual Proteins for which structural information is available. The crystal structures of the DHO and ATC domains of human CAD were recently reported. The GLN and CPS domains of CAD are expected to be similar to the Escherichia coli CPS and human mitochondrial CPS1 crystal structures. A model of CAD is proposed that sets the DHO and ATC domains as the central framework of the hexameric particles. Keywords: nucleotide metabolism; Multifunctional Protein; glutaminase; carbamoyl phosphate synthetase; dihydroorotase; aspartate transcarbamoylase; URA2; Protein structure; X-ray crystallography
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structural insight into the core of cad the Multifunctional Protein leading de novo pyrimidine biosynthesis
Structure, 2017Co-Authors: Maria Morenomorcillo, A Grandegarcia, Alba Ruizramos, Francisco Del Canoochoa, Jasminka Boskovic, Santiago RamonmaiquesAbstract:Summary CAD, the Multifunctional Protein initiating and controlling de novo biosynthesis of pyrimidines in animals, self-assembles into ∼1.5 MDa hexamers. The structures of the dihydroorotase (DHO) and aspartate transcarbamoylase (ATC) domains of human CAD have been previously determined, but we lack information on how these domains associate and interact with the rest of CAD forming a multienzymatic unit. Here, we prove that a construct covering human DHO and ATC oligomerizes as a dimer of trimers and that this arrangement is conserved in CAD-like from fungi, which holds an inactive DHO-like domain. The crystal structures of the ATC trimer and DHO-like dimer from the fungus Chaetomium thermophilum confirm the similarity with the human CAD homologs. These results demonstrate that, despite being inactive, the fungal DHO-like domain has a conserved structural function. We propose a model that sets the DHO and ATC complex as the central element in the architecture of CAD.
Paul P Van Veldhoven - One of the best experts on this subject based on the ideXlab platform.
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peroxisomal Multifunctional Protein 2 deficiency causes neuroinflammation and degeneration of purkinje cells independent of very long chain fatty acid accumulation
Neurobiology of Disease, 2013Co-Authors: Simon Verheijden, Paul P Van Veldhoven, Astrid Bottelbergs, Olga Krysko, Dmitri V Krysko, Lien Beckers, Stephanie De Munter, Sabine Wyns, Wim Kulik, Klausarmin NaveAbstract:Although peroxisome biogenesis and β-oxidation disorders are well known for their neurodevelopmental defects, patients with these disorders are increasingly diagnosed with neurodegenerative pathologies. In order to investigate the cellular mechanisms of neurodegeneration in these patients, we developed a mouse model lacking Multifunctional Protein 2 (MFP2, also called D-bifunctional Protein), a central enzyme of peroxisomal β-oxidation, in all neural cells (Nestin-Mfp2(-/-)) or in oligodendrocytes (Cnp-Mfp2(-/-)) and compared these models with an already established general Mfp2 knockout. Nestin-Mfp2 but not Cnp-Mfp2 knockout mice develop motor disabilities and ataxia, similar to the general mutant. Deterioration of motor performance correlates with the demise of Purkinje cell axons in the cerebellum, which precedes loss of Purkinje cells and cerebellar atrophy. This closely mimics spinocerebellar ataxias of patients affected with mild peroxisome β-oxidation disorders. However, general knockouts have a much shorter life span than Nestin-Mfp2 knockouts which is paralleled by a disparity in activation of the innate immune system. Whereas in general mutants a strong and chronic proinflammatory reaction proceeds throughout the brain, elimination of MFP2 from neural cells results in minor neuroinflammation. Neither the extent of the inflammatory reaction nor the cerebellar degeneration could be correlated with levels of very long chain fatty acids, substrates of peroxisomal β-oxidation. In conclusion, MFP2 has multiple tasks in the adult brain, including the maintenance of Purkinje cells and the prevention of neuroinflammation but this is not mediated by its activity in oligodendrocytes nor by its role in very long chain fatty acid degradation.
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peroxisomal Multifunctional Protein 2 the enzyme the patients and the knockout mouse model
Biochimica et Biophysica Acta, 2006Co-Authors: Steven Huyghe, Guy P Mannaerts, Myriam Baes, Paul P Van VeldhovenAbstract:The mammalian Multifunctional Protein-2 (MFP-2, also called Multifunctional enzyme 2, D-bifunctional enzyme or 17-beta-estradiol dehydrogenase type IV) was identified by several groups about a decade ago. It plays a central role in peroxisomal beta-oxidation as it handles most, if not all, peroxisomal beta-oxidation substrates. Deficiency of this enzyme in man causes a severe developmental syndrome with abnormalities in several organs but in particular in the brain, leading to death within the first year of life. Accumulation of branched-long-chain fatty acids and very-long-chain fatty acids and a disturbed synthesis of bile acids were documented in these patients. A mouse model with MFP-2 deficiency only partly phenocopies the human disease. Although the expected metabolic abnormalities are present, no neurodevelopmental aberrations are observed. However, the survival of these mice into adulthood allowed to document the importance of this enzyme for the normal functioning of the brain, eyes and testis. In the present review, the identification and biochemical characteristics of MFP-2, and the consequences of MFP-2 dysfunction in humans and in mice will be discussed.
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the human peroxisomal Multifunctional Protein involved in bile acid synthesis activity measurement deficiency in zellweger syndrome and chromosome mapping
Biochimica et Biophysica Acta, 1997Co-Authors: Dmitry Novikov, Martine Dieuaidenoubhani, Joris Vermeesch, Beatrice Fournier, Guy P Mannaerts, Paul P Van VeldhovenAbstract:Abstract The dehydrogenation of 24R,25R-varanoyl-CoA, the physiological intermediate formed during the peroxisomal breakdown of the bile acid intermediate trihydroxycoprostanic acid, was studied in human liver. The reaction appeared to be catalyzed by two different enzymes. A first one, present in the cytosol, did not discriminate between the four possible varanoyl-CoA isomers and did not require the CoA moiety. The second enzymic activity was associated with peroxisomes and acted only on the 24R,25R-isomer, in which the 24-hydroxy group possesses the d -configuration. The d -specific dehydrogenase is part of a 79 kDa Protein which represents the human counterpart of a recently discovered second Multifunctional Protein in rat liver peroxisomes, named Multifunctional Protein 2 (MFP-2). Human MFP-2, like its rat counterpart, is also responsible for the formation (by hydratation) of 24R,25R-varanoyl-CoA. A deficiency of MFP-2 in Zellweger liver could be demonstrated immunologically by using antibodies against the rat enzyme and enzymically — after removal of the cytosol — by using 24R,25R-varanoyl-CoA. The gene coding for MFP-2 was mapped to chromosome 5q2.3. ©1997 Elsevier Science B.V. All rights reserved.
Frederic Sigoillot - One of the best experts on this subject based on the ideXlab platform.
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Protein kinase a phosphorylation of the Multifunctional Protein cad antagonizes activation by the map kinase cascade
Molecular and Cellular Biochemistry, 2007Co-Authors: Damian H Kotsis, Frederic Sigoillot, Elizabeth Masko, Roberto Di Gregorio, Hedeel Guyevans, David R EvansAbstract:The flux through the de novo pyrimidine biosynthetic pathway is controlled by the Multifunctional Protein CAD, which catalyzes the first three steps. The cell cycle dependent regulation of pyrimidine biosynthesis is a consequence of sequential phosphorylation of CAD Thr456 and Ser1406 by the MAP kinase and PKA cascades, respectively. Coordinated regulation of the pathway requires precise timing of the two phosphorylation events. These studies show that phosphorylation of purified CAD by PKA antagonizes MAP kinase phosphorylation, and vice versa. Similar results were observed in vivo. Forskolin activation of PKA in BHK-21 cells resulted in a 8.5 fold increase in Ser1406 phosphorylation and severely curtailed the MAP kinase mediated phosphorylation of CAD Thr456. Moreover, the relative activity of MAP kinase and PKA was found to determine the extent of Thr456 phosphorylation. Transfectants expressing elevated levels of MAP kinase resulted in a 11-fold increase in Thr456 phosphorylation, whereas transfectants that overexpress PKA reduced Thr456 phosphorylation 5-fold. While phosphorylation of one site by one kinase may induce conformational changes that interfere with phosphorylation by the other, the observation that both MAP kinase and PKA form stable complexes with CAD suggest that the mutual antagonism is the result of steric interference by the bound kinases. The reciprocal antagonism of CAD phosphorylation by MAP kinase and PKA provides an elegant mechanism to coordinate the cell cycle-dependent regulation of pyrimidine biosynthesis ensuring that signals for up- and down-regulation of the pathway do not conflict.
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autophosphorylation of the mammalian Multifunctional Protein that initiates de novo pyrimidine biosynthesis
Journal of Biological Chemistry, 2002Co-Authors: Frederic Sigoillot, David R EvansAbstract:Abstract CAD, a large Multifunctional Protein that carries carbamoyl phosphate synthetase (CPSase), aspartate transcarbamoylase, and dihydroorotase activities, catalyzes the first three steps of de novo pyrimidine biosynthesis in mammalian cells. The CPSase component, which catalyzes the initial, rate-limiting step, exhibits complex regulatory mechanisms involving allosteric effectors and phosphorylation that control the flux of metabolites through the pathway. Incubation of CAD with ATP in the absence of exogenous kinases resulted in the incorporation of 1 mol of Pi/mol of CAD monomer. Mass spectrometry analysis of tryptic digests showed that Thr1037 located within the CAD CPS.B subdomain was specifically modified. The reaction is specific for MgATP, ADP was a competitive inhibitor, and the native tertiary structure of the Protein was required. Phosphorylation occurred after denaturation, further purification of CAD by SDS gel electrophoresis, and renaturation on a nitrocellulose membrane, strongly suggesting that phosphate incorporation resulted from an intrinsic kinase activity and was not the result of contaminating kinases. Chemical modification with the ATP analog, 5′-p-fluorosulfonylbenzoyladenosine, showed that one or both of the active sites that catalyze the ATP-dependent partial reactions are also involved in autophosphorylation. The rate of phosphorylation was dependent on the concentration of CAD, indicating that the reaction was, at least in part, intermolecular. Autophosphorylation resulted in a 2-fold increase in CPSase activity, an increased sensitivity to the feedback inhibitor UTP, and decreased allosteric activation by 5-phosphoribosyl-1-pyrophosphate, functional changes that were distinctly different from those resulting from phosphorylation by either the Protein kinase A or mitogen-activated Protein kinase cascades.