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Riu IH, Shin IS, Do SI. Sp1 modulates ncOGT activity to alter target recognition and enhanced thermotolerance in E. coli. Biochem Biophys Res Commun 2008; 372:203-9. [PMID: 18486602 DOI: 10.1016/j.bbrc.2008.05.034] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2008] [Accepted: 05/05/2008] [Indexed: 10/22/2022]
Abstract
cDNAs encoding three isoforms of OGT (ncOGT, mOGT, and sOGT) were expressed in Escherichia coli in which the coexpression system of OGT with target substrates was established in vivo. No endogenous bacterial proteins were significantly O-GlcNAcylated by any type of OGT isoform while co-expressed p62 and Sp1 were strongly O-GlcNAcylated by ncOGT. These results suggest that most of bacterial proteins appear not to be recognized as right substrates by mammalian OGT whereas cytosolic environments may supply UDP-GlcNAc enough to proceed to O-GlcNAcylation in E. coli. Under these conditions, sOGT was auto-O-GlcNAcylated whereas ncOGT and mOGT were not. Importantly, we found that when Sp1 was coexpressed, ncOGT can O-GlcNAcylate not only Sp1 but also many bacterial proteins. Our findings suggest that Sp1 may modulate the capability of target recognition of ncOGT by which ncOGT can be led to newly recognize bacterial proteins as target substrates, finally generating the O-glyco-bacteria. Our results demonstrate that the O-glyco-bacteria showed enhanced thermal resistance to allow cell survival at a temperature as high as 52 degrees C.
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Affiliation(s)
- In-Hyun Riu
- Department of Life Science, Laboratory of Functional Glycomics, Ajou University, San 5, Wonchon-dong, Youngtong-gu, Suwon City 443-749, Republic of Korea
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52
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Xing D, Feng W, Nöt LG, Miller AP, Zhang Y, Chen YF, Majid-Hassan E, Chatham JC, Oparil S. Increased protein O-GlcNAc modification inhibits inflammatory and neointimal responses to acute endoluminal arterial injury. Am J Physiol Heart Circ Physiol 2008; 295:H335-42. [PMID: 18469144 DOI: 10.1152/ajpheart.01259.2007] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Inflammation plays a major role in vascular disease. We have shown that leukocyte infiltration and inflammatory mediator expression contribute to vascular remodeling after endoluminal injury. This study tested whether increasing protein O-linked-N-acetylglucosamine (O-GlcNAc) levels with glucosamine (GlcN) and O-(2-acetamido-2-deoxy-d-glucopyranosylidene) amino-N-phenylcarbamate (PUGNAc) inhibits acute inflammatory and neointimal responses to endoluminal arterial injury. Ovariectomized rats were treated with a single injection of GlcN (0.3 mg/g ip), PUGNAc (7 nmol/g ip) or vehicle (V) 2 h before balloon injury of the right carotid artery. O-GlcNAc-modified protein levels decreased markedly in injured arteries of V-treated rats at 30 min, 2 h, and 24 h after injury but returned to control (contralateral uninjured) levels after 14 days. Both GlcN and PUGNAc increased O-GlcNAc-modified protein levels in injured arteries compared with V controls at 30 min postinjury; the GlcN-mediated increase persisted at 24 h but was not evident at 14 days. Proinflammatory mediator expression increased markedly after injury and was reduced significantly (30-50%) by GlcN and PUGNAc. GlcN and PUGNAc also inhibited infiltration of neutrophils and monocytes in injured arteries. Chronic (14 days) treatment with GlcN reduced neointima formation in injured arteries by 50% compared with V controls. Acute GlcN and PUGNAc treatment increases O-GlcNAc-modified protein levels and inhibits acute inflammatory responses in balloon-injured rat carotid arteries; 14 day GlcN treatment inhibits neointima formation in these vessels. Augmenting O-GlcNAc modification of proteins in the vasculature may represent a novel anti-inflammatory and vasoprotective mechanism.
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Affiliation(s)
- Dongqi Xing
- Department of Medicine, Univ. of Alabama at Birmingham, Birmingham, Alabama 35294, USA.
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53
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Laurent N, Voglmeir J, Wright A, Blackburn J, Pham NT, Wong SCC, Gaskell SJ, Flitsch SL. Enzymatic glycosylation of peptide arrays on gold surfaces. Chembiochem 2008; 9:883-7. [PMID: 18330850 PMCID: PMC2635019 DOI: 10.1002/cbic.200700692] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2007] [Indexed: 11/10/2022]
Affiliation(s)
- Nicolas Laurent
- Manchester Interdisciplinary Biocentre and School of Chemistry The University of Manchester 131 Princess Street Manchester M1 7DN (UK)
| | - Josef Voglmeir
- Manchester Interdisciplinary Biocentre and School of Chemistry The University of Manchester 131 Princess Street Manchester M1 7DN (UK)
| | - Adam Wright
- Manchester Interdisciplinary Biocentre and School of Chemistry The University of Manchester 131 Princess Street Manchester M1 7DN (UK)
| | - Jonathan Blackburn
- Centre for Proteomic and Genomic Research Institute of Infectious Disease & Molecular Medicine, University of Cape Town Observatory 7925 Cape Town (South Africa)
| | - Nhan T. Pham
- SUPA and School of Physics, University of Edinburgh Kings Buildings, Mayfield Road, Edinburgh EH9 3JZ (UK)
| | - Stephen C. C. Wong
- Manchester Interdisciplinary Biocentre and School of Chemistry The University of Manchester 131 Princess Street Manchester M1 7DN (UK)
| | - Simon J. Gaskell
- Manchester Interdisciplinary Biocentre and School of Chemistry The University of Manchester 131 Princess Street Manchester M1 7DN (UK)
| | - Sabine L. Flitsch
- Manchester Interdisciplinary Biocentre and School of Chemistry The University of Manchester 131 Princess Street Manchester M1 7DN (UK)
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54
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Abstract
An early and rapid response to severe injury or trauma is the development of hyperglycemia, which has long been thought to be an essential survival response by providing fuel for vital organ systems and facilitating mobilization of interstitial fluid reserves by increasing osmolarity. However, glucose can also be metabolized via the hexosamine biosynthesis pathway (HBP), leading to the synthesis of uridine diphosphate N-acetyl-glucosamine(UDP-GlcNAc). UDP-GlcNAc is a substrate for the addition, via an O-linkage, of a single N-acetylglucosamine to serine or threonine residues of nuclear and cytoplasmic proteins (O-glycosylation, O-GlcNAc). There is increasing appreciation that protein O-glycosylation is a highly dynamic posttranslational modification that plays a key role in signal transduction pathways. Sustained increases in O-GlocNAc have been implicated in the development of diabetes and diabetic complications; however, recent studies have demonstrated that stress leads to a transient increase in O-GlcNAc levels that is associated with increased tolerance to stress. Indeed, activation of pathways leading to O-GlcNAc formation improves cell survival after I/R injury, whereas inhibition of O-GlcNAc formation decreases cell survival. In addition, in rodent models of trauma-hemorrhage, increasing O-GlcNAc levels during resuscitation improves cardiac function and organ perfusion and attenuates the inflammatory response. At the cellular level, increasing O-GlcNAc levels attenuates nuclear factor-kappaB activation. It is noteworthy that other metabolic-based treatments for severe injury such as glucose-insulin-potassium and glutamine also lead to increased HBP flux and O-GlcNAc levels. The goal of this review is to summarize our current understanding of the role of the HBP and O-GlcNAc on the regulation of cell function and survival and to present evidence to support the notion that activation of these pathways represents a novel treatment strategy for severe injury and trauma.
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Affiliation(s)
- John C Chatham
- Department of Medicine, Division of Cardiovascular Disease, University of Alabama at Birmingham, Birmingham, Alabama 35294-0005, USA.
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55
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Immunochemical methods for the rapid screening of the o-glycosidically linked N-acetylglucosamine modification of proteins. METHODS IN MOLECULAR BIOLOGY (CLIFTON, N.J.) 2008; 446:267-80. [PMID: 18373264 DOI: 10.1007/978-1-60327-084-7_19] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
for the rapid screening of specific post-translational modifications antibody-based methods are very well suited and applicable without demanding expenditure. Here we describe the immunochemical detection of the O-glycosidically linked cytosolic N-acetylglucosamine modification of proteins, which has attracted increasing interest in the last years. Two different monoclonal antibodies were used in enzyme-linked immunosorbent assays (ELISA), Western blots of 1- and 2- dimension (1D and 2D) separated proteins and immunohistochemical analysis of tissue sections. Slight differences in the recognition of this post-translational epitope by the 2 antibodies are observed and will be discussed.
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56
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Broyer RM, Quaker GM, Maynard HD. Designed amino acid ATRP initiators for the synthesis of biohybrid materials. J Am Chem Soc 2008; 130:1041-7. [PMID: 18161975 DOI: 10.1021/ja0772546] [Citation(s) in RCA: 94] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A synthetic strategy to prepare peptide-polymer conjugates with precise sites of attachment is described. Amino acids modified with atom transfer radical polymerization (ATRP) initiators for the polymerization of styrenes and methacrylates were prepared. Fmoc-4-(1-chloroethyl)-phenylalanine (5) was synthesized in four steps from Fmoc-tyrosine. HATU-mediated amidation with glycine-OMe resulted in dipeptide (6). The initiator was effective for Cu(I)/bipyridine mediated bulk polymerization of styrene. Kinetic studies indicated a controlled polymerization, with high conversion (97%), and a polydispersity index (PDI) of 1.25. Fmoc-O-(2-bromoisobutyryl)-serine tert-butyl ester (10) was synthesized from Fmoc-Ser(OTrt)-OH in three steps. This initiator was employed in the ATRP of 2-hydroxyethyl methacrylate (HEMA), and kinetic studies indicated a controlled polymerization. Different monomer to initiator ratios resulted in poly(HEMA) of different molecular weights and narrow PDIs (1.14-1.25). Conversions were between 70 and 99%. HEMA modified with N-acetyl-D-glucosamine (GlcNAc) was also polymerized to 84% conversion and the resulting PDI was 1.19. The t-butyl ester protecting group of 10 was removed, and the resulting amino acid (11) was incorporated into VM(11)VVQTK by standard solid-phase peptide synthesis. Polymerization resulted in the glycopolymer-peptide conjugate in 93% conversion and a PDI of 1.14.
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Affiliation(s)
- Rebecca M Broyer
- Department of Chemistry and Biochemistry and the California NanoSystems Institute, University of California, 607 Charles E. Young Drive East, Los Angeles, California 90096-1569, USA
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57
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Fülöp N, Feng W, Xing D, He K, Nőt LG, Brocks CA, Marchase RB, Miller AP, Chatham JC. Aging leads to increased levels of protein O-linked N-acetylglucosamine in heart, aorta, brain and skeletal muscle in Brown-Norway rats. Biogerontology 2008; 9:139. [PMID: 18185980 DOI: 10.1007/s10522-007-9123-5] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2007] [Accepted: 12/19/2007] [Indexed: 10/22/2022]
Abstract
Changes in the levels of O-linked N-acetyl-glucosamine (O-GlcNAc) on nucleocytoplasmic protein have been associated with a number of age-related diseases such as Alzheimer's and diabetes; however, there is relatively little information regarding the impact of age on tissue O-GlcNAc levels. Therefore, the goal of this study was to determine whether senescence was associated with alterations in O-GlcNAc in heart, aorta, brain and skeletal muscle and if so whether there were also changes in the expression of enzymes critical in regulating O-GlcNAc levels, namely, O-GlcNAc transferase (OGT), O-GlcNAcase and glutamine:fructose-6-phosphate amidotransferase (GFAT). Tissues were harvested from 5- and 24-month old Brown-Norway rats; UDP-GlcNAc, a precursor of O-GlcNAc was assessed by HPLC, O-GlcNAc and OGT levels were assessed by immunoblot analysis and GFAT1/2, OGT, O-GlcNAcase mRNA levels were determined by RT-PCR. In the 24-month old animals serum insulin and triglyceride levels were significantly increased compared to the 5-month old group; however, glucose levels were unchanged. Protein O-GlcNAc levels were significantly increased with age (30-107%) in all tissues examined; however, paradoxically the expression of OGT, which catalyzes O-GlcNAc formation, was decreased by approximately 30% in the heart, aorta and brain. In the heart increased O-GlcNAc was associated with increased UDP-GlcNAc levels and elevated GFAT mRNA while in other tissues we found no difference in UDP-GlcNAc or GFAT mRNA levels. These results demonstrate that senescence is associated with increased O-GlcNAc levels in multiple tissues and support the notion that dysregulation of pathways leading to O-GlcNAc formation may play an important role in the development of age-related diseases.
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Affiliation(s)
- Norbert Fülöp
- Department of Medicine, University of Alabama at Birmingham, Birmingham, AL, 35294-0005, USA
| | - Wenguang Feng
- Department of Medicine, University of Alabama at Birmingham, Birmingham, AL, 35294-0005, USA
| | - Dongqi Xing
- Department of Medicine, University of Alabama at Birmingham, Birmingham, AL, 35294-0005, USA
| | - Kai He
- Department of Medicine, University of Alabama at Birmingham, Birmingham, AL, 35294-0005, USA
| | - László G Nőt
- Department of Cell Biology, MCLM 684, University of Alabama at Birmingham, Birmingham, AL, 35294, USA
| | - Charlye A Brocks
- Department of Medicine, University of Alabama at Birmingham, Birmingham, AL, 35294-0005, USA
| | - Richard B Marchase
- Department of Cell Biology, MCLM 684, University of Alabama at Birmingham, Birmingham, AL, 35294, USA
| | - Andrew P Miller
- Department of Medicine, University of Alabama at Birmingham, Birmingham, AL, 35294-0005, USA
| | - John C Chatham
- Department of Medicine, University of Alabama at Birmingham, Birmingham, AL, 35294-0005, USA.
- Department of Cell Biology, MCLM 684, University of Alabama at Birmingham, Birmingham, AL, 35294, USA.
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58
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Azuma Y, Miura K, Higai K, Matsumoto K. Protein O-N-acetylglucosaminylation modulates promoter activities of cyclic AMP response element and activator protein 1 and enhances E-selectin expression on HuH-7 human hepatoma cells. Biol Pharm Bull 2008; 30:2284-9. [PMID: 18057713 DOI: 10.1248/bpb.30.2284] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
High glucose accelerates O-N-acetylglucosaminylation (O-GlcNAcylation) of proteins and causes diabetic complications. In the present study, we found that treatment of HuH-7 human hepatoma cells with high glucose or the protein O-N-acetylglucosaminidase (O-GlcNAcase) inhibitor O-(2-acetoamide-2-deoxy-D-glucopyranosylidene)amino-N-phenylcarbamate (PUGNAc) increased the cell surface expression of E-selectin. A dual luciferase reporter assay indicated that high glucose and PUGNAc suppressed promoter activities of the cyclic AMP response element (CRE) and enhanced those of activator protein 1 (AP-1). Enhanced CRE promoter activities in HuH-7 cells treated with dibutyryl cAMP or co-transfected with a protein kinase A expression vector pFC-PKA that enhances the phosphorylation of CRE binding protein (CREB) were suppressed by PUGNAc. In contrast, PUGNAc further increased the enhanced AP-1 promoter activity in cells transfected with a mitogen-activated protein kinase kinase kinase expression vector pFC-MEKK that enhances c-Jun phosphorylation. Immuno-blotting using an anti-O-GlcNAc antibody revealed that high glucose and PUGNAc accelerated protein O-GlcNAcylation and that there were substantial differences in the O-GlcNAcylated proteins in the cytoplasmic and nuclear fractions. In addition, PUGNAc increased the nuclear import of O-GlcNAcylated CREB. These results suggest that protein O-GlcNAcylation modulates the promoter activities of E-selectin gene, suppression of CRE and enhancement of AP-1, and enhances E-selectin protein expression on hepatocytes.
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Affiliation(s)
- Yutaro Azuma
- Department of Clinical Chemistry, School of Pharmaceutical Sciences, Toho University, 2-2-1 Miyama, Funabashi, Chiba247-8510, Japan.
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59
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Bork K, Kannicht C, Nöhring S, Reutter W, Weidemann W, Hart GW, Horstkorte R. N-Propanoylmannosamine interferes with O-GlcNAc modification of the tyrosine 3-monooxygenase and stimulates dopamine secretion. J Neurosci Res 2008; 86:647-52. [PMID: 17896794 DOI: 10.1002/jnr.21526] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
The most consistent neurochemical abnormality in Parkinson's disease is degeneration of dopaminergic neurons in the substantia nigra, leading to a reduction of striatal dopamine levels. The rate-limiting step in the biosynthesis of dopamine, noradrenalin, and adrenalin is catalyzed by tyrosine 3-monooxygenase (=tyrosine hydroxylase), which catalyzes the formation of L-DOPA. In earlier studies, we demonstrated that the novel synthetic sialic acid precursor N-propanoylmannosamine is a potent stimulator of axonal growth and promotes reestablishment of the perforant pathway from layer II of cortical neurons to the outer molecular layer of the dentate gyrus. Here we show that application of N-propanoylmannosamine leads to increased biosynthesis and secretion of dopamine. This increased biosynthesis of dopamine is due to decreased expression of O-linked N-acetylglucosamine on tyrosine 3-monooxygenase. Intracellular attachment of O-linked N-acetylglucosamine to serine and threonine residues hinders phosphorylation, thereby regulating the activity of the proteins concerned. We therefore propose a model in which the application of ManNProp leads to increased phosphorylation and activation of tyrosine 3-monooxygenase, which in turn leads to an increased synthesis of dopamine.
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Affiliation(s)
- Kaya Bork
- Charité-Universitätsmedizin Berlin, Berlin, Germany
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60
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Nakano S, Shinde A, Fujita K, Ito H, Kusaka H. Histone H1 is released from myonuclei and present in rimmed vacuoles with DNA in inclusion body myositis. Neuromuscul Disord 2008; 18:27-33. [PMID: 17888663 DOI: 10.1016/j.nmd.2007.08.005] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2007] [Revised: 08/06/2007] [Accepted: 08/14/2007] [Indexed: 10/22/2022]
Abstract
To investigate myonuclear alterations in sporadic inclusion body myositis (s-IBM), we immuno-localized histones in muscles in 11 patients. The examination showed that vacuolar rims were frequently positive for histone H1. In triple-color fluorescence study, the H1-positive products were found on the inner side of an emerin-positive circle with DNA. Moreover, H1-positive materials appeared to be released into the cytoplasm in some vacuoles and myonuclei. The localization of H1 was different from phosphorylated Elk-1, which is a nuclear protein, but abnormally accumulated in the cytoplasm in s-IBM. The results strongly support the hypothesis that rimmed vacuoles are derived from the nucleus. The cytoplasmic H1-release suggests dysfunction of nuclear membranes in an early phase of the nuclear disintegration. We hypothesize that, in s-IBM muscles, compromised nuclear envelope may permit release of some nuclear components such as histone H1 and cannot facilitate the incorporation of others to the nucleus as in pElk-1.
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MESH Headings
- Active Transport, Cell Nucleus/genetics
- Aged
- Aged, 80 and over
- Cell Nucleus/metabolism
- Cell Nucleus/pathology
- Cytoplasm/metabolism
- Cytoplasm/pathology
- DNA/genetics
- DNA/metabolism
- Female
- Fluorescent Antibody Technique/methods
- Histones/genetics
- Histones/metabolism
- Humans
- Male
- Middle Aged
- Muscle Fibers, Skeletal/metabolism
- Muscle Fibers, Skeletal/pathology
- Muscle, Skeletal/metabolism
- Muscle, Skeletal/pathology
- Muscle, Skeletal/physiopathology
- Myositis, Inclusion Body/metabolism
- Myositis, Inclusion Body/pathology
- Myositis, Inclusion Body/physiopathology
- Nuclear Envelope/metabolism
- Nuclear Envelope/pathology
- Vacuoles/metabolism
- Vacuoles/pathology
- ets-Domain Protein Elk-1/genetics
- ets-Domain Protein Elk-1/metabolism
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Affiliation(s)
- Satoshi Nakano
- Department of Neurology, Kansai Medical University, Moriguchi 570-8507, Japan.
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61
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Gesslbauer B, Rek A, Falsone F, Rajkovic E, Kungl AJ. Proteoglycanomics: tools to unravel the biological function of glycosaminoglycans. Proteomics 2007; 7:2870-80. [PMID: 17654462 DOI: 10.1002/pmic.200700176] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Glycosylation is the most frequent PTM and contributes significantly to the function of proteins depending on the type of glycosylation. Especially glycan structures like the glycosaminoglycans are considered to constitute themselves the major function of the glycoconjugate which is therefore termed proteoglycan. Here we review recent views on and novel tools for analysing the proteoglycanome, which are directly related to the type of glycanation under investigation. We define the major function of the proteoglycanome to be its interaction with various proteins in many different (patho-)physiological conditions. This is exemplified by the differential glycosaminoglycan-interactome of healthy versus arthritic patient sera.
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Affiliation(s)
- Bernd Gesslbauer
- Institute of Pharmaceutical Sciences, University of Graz, Graz, Austria
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62
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Nöt LG, Marchase RB, Fülöp N, Brocks CA, Chatham JC. Glucosamine administration improves survival rate after severe hemorrhagic shock combined with trauma in rats. Shock 2007; 28:345-52. [PMID: 17545939 DOI: 10.1097/shk.0b013e3180487ebb] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
We have previously shown that glucosamine administration resulted in higher cardiac output and improved tissue perfusion after trauma-hemorrhage with resuscitation in rats, which was associated with the increased levels of protein O-linked-N-acetylglucosamine (O-GlcNAc). The purpose of the study was to evaluate the effect of glucosamine on the survival, without resuscitation, in rats. Adult male rats underwent midline laparotomy and 55% of total blood volume was withdrawn for 25 min under isoflurane anesthesia. At the end of the hemorrhage period, 2.5 mL of 150 mM glucosamine or equivalent osmolarity of mannitol solution was injected intravenously for 10 min. The survival time, mean blood pressure, heart rate, and central body temperature were monitored continuously; then, the O-GlcNAc levels in heart, brain, liver, and muscle were measured by means of Western blot analysis. Glucosamine administration significantly increased the survival rate in comparison with mannitol administration (percentage of survival after 2 h, 47% vs. 20%; P < 0.05). The mean arterial pressure was significantly higher in the glucosamine group for 18 min after treatment. The protein O-GlcNAc levels, assessed 30 min after glucosamine treatment, were significantly increased in the heart, brain, and liver. These data demonstrate that i.v. glucosamine administration improves the survival rate after trauma-hemorrhage without resuscitation; this effect may be related to the glucosamine-induced increase in protein O-glycosylation. Furthermore, the increase in mean arterial pressure may suggest a vasoactive and/or positive inotropic effect of glucosamine in hypovolemic shock.
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Affiliation(s)
- Laszlo G Nöt
- Department of Cell Biology, University of Alabama at Birmingham, Birmingham, Alabama 35294-0005, USA
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63
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Ahmad I, Hoessli DC, Gupta R, Walker-Nasir E, Rafik SM, Choudhary MI, Shakoori AR. In silico determination of intracellular glycosylation and phosphorylation sites in human selectins: implications for biological function. J Cell Biochem 2007; 100:1558-72. [PMID: 17230456 DOI: 10.1002/jcb.21156] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Post-translational modifications provide the proteins with the possibility to perform functions in addition to those determined by their primary sequence. However, analysis of multifunctional protein structures in the environment of cells and body fluids is made especially difficult by the presence of other interacting proteins. Bioinformatics tools are therefore helpful to predict protein multifunctionality through the identification of serine and threonine residues wherein the hydroxyl group is likely to become modified by phosphorylation or glycosylation. Moreover, serines and threonines where both modifications are likely to occur can also be predicted (YinYang sites), to suggest further functional versatility. Structural modifications of hydroxyl groups of P-, E-, and L-selectins have been predicted and possible functions resulting from such modifications are proposed. Functional changes of the three selectins are based on the assumption that transitory and reversible protein modifications by phosphate and O-GlcNAc cause specific conformational changes and generate binding sites for other proteins. The computer-assisted prediction of glycosylation and phosphorylation sites in selectins should be helpful to assess the contribution of dynamic protein modifications in selectin-mediated inflammatory responses and cell-cell adhesion processes that are difficult to determine experimentally.
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Affiliation(s)
- Ishtiaq Ahmad
- Institute of Molecular Sciences and Bioinformatics, Lahore, Pakistan
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64
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Jang BC, Sung SH, Park JG, Park JW, Bae JH, Shin DH, Park GY, Han SB, Suh SI. Glucosamine hydrochloride specifically inhibits COX-2 by preventing COX-2 N-glycosylation and by increasing COX-2 protein turnover in a proteasome-dependent manner. J Biol Chem 2007; 282:27622-32. [PMID: 17635918 DOI: 10.1074/jbc.m610778200] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
COX-2 and its products, including prostaglandin E(2), are involved in many inflammatory processes. Glucosamine (GS) is an amino monosaccharide and has been widely used for alternative regimen of (osteo) arthritis. However, the mechanism of action of GS on COX-2 expression remains unclear. Here we describe a new action mechanism of glucosamine hydrochloride (GS-HCl) to tackle endogenous and agonist-driven COX-2 at protein level. GS-HCl (but not GS sulfate, N-acetyl GS, or galactosamine HCl) resulted in a shift in the molecular mass of COX-2 from 72-74 to 66-70 kDa and concomitant inhibition of prostaglandin E(2) production in a concentration-dependent manner in interleukin (IL)-1beta-treated A549 human lung epithelial cells. Remarkably, GS-HCl-mediated decrease in COX-2 molecular mass was associated with inhibition of COX-2 N-glycosylation during translation, as assessed by the effect of tunicamycin, the protein N-glycosylation inhibitor, or of cycloheximide, the translation inhibitor, on COX-2 modification. Specifically, the effect of low concentration of GS-HCl (1 mM) or of tunicamycin (0.1 microg/ml) to produce the aglycosylated COX-2 was rescued by the proteasomal inhibitor MG132 but not by the lysosomal or caspase inhibitors. However, the proteasomal inhibitors did not show an effect at 5 mM GS-HCl, which produced the aglycosylated or completely deglycosylated form of COX-2. Notably, GS-HCl (5 mM) also facilitated degradation of the higher molecular species of COX-2 in IL-1beta-treated A549 cells that was retarded by MG132. GS-HCl (5 mM) was also able to decrease the molecular mass of endogenous and IL-1beta- or tumor necrosis factor-alpha-driven COX-2 in different human cell lines, including Hep2 (bronchial) and H292 (laryngeal). However, GS-HCl did not affect COX-1 protein expression. These results demonstrate for the first time that GS-HCl inhibits COX-2 activity by preventing COX-2 co-translational N-glycosylation and by facilitating COX-2 protein turnover during translation in a proteasome-dependent manner.
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Affiliation(s)
- Byeong-Churl Jang
- Chronic Disease Research Center and Institute for Medical Science, Keimyung University School of Medicine, Daegu, South Korea.
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65
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Hedou J, Cieniewski-Bernard C, Leroy Y, Michalski JC, Mounier Y, Bastide B. O-linked N-acetylglucosaminylation is involved in the Ca2+ activation properties of rat skeletal muscle. J Biol Chem 2007; 282:10360-9. [PMID: 17289664 DOI: 10.1074/jbc.m606787200] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
O-Linked N-acetylglucosaminylation termed O-GlcNAc is a dynamic cytosolic and nuclear glycosylation that is dependent both on glucose flow through the hexosamine biosynthesis pathway and on phosphorylation because of the existence of a balance between phosphorylation and O-GlcNAc. This glycosylation is a ubiquitous post-translational modification, which probably plays an important role in many aspects of protein functions. We have previously reported that, in skeletal muscle, proteins of the glycolytic pathway, energetic metabolism, and contractile proteins were O-GlcNAc-modified and that O-Glc-NAc variations could control the muscle protein homeostasis and be implicated in the regulation of muscular atrophy. In this paper, we report O-N-acetylglucosaminylation of a number of key contractile proteins (i.e. myosin heavy and light chains and actin), which suggests that this glycosylation could be involved in skeletal muscle contraction. Moreover, our results showed that incubation of skeletal muscle skinned fibers in N-acetyl-d-glucosamine, in a concentration solution known to inhibit O-GlcNAc-dependent interactions, induced a decrease in calcium sensitivity and affinity of muscular fibers, whereas the cooperativity of the thin filament proteins was not modified. Thus, our results suggest that O-GlcNAc is involved in contractile protein interactions and could thereby modulate muscle contraction.
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Affiliation(s)
- Julie Hedou
- Laboratoire de Plasticité Neuromusculaire, Unité de Neurosciences et Physiologie Adaptatives, UPRES EA 4052, 59655 Villeneuve d'Ascq Cedex, France
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66
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Abstract
O-linked N-acetylglucosamine (O-GlcNAc) is a monosaccharide posttranslational modification that modifies serine/threonine residues of nucleocytoplasmic proteins in metazoans. O-GlcNAc, like phosphorylation, is dynamic and responsive to numerous stimuli in diverse regulatory pathways. O-GlcNAc may also be found adjacent to or at the same sites as phosphorylation, demonstrating the potential for a reciprocal function on some of these proteins. Like most posttranslational modifications, O-GlcNAc is substoichiometric and may be found at multiple sites with other posttranslational modifications present. Additionally, there is no consensus sequence defining the addition of O-GlcNAc to the peptide backbone, further complicating identification and site mapping. This chapter describes several strategies to confirm that proteins are O-GlcNAc modified and provide subsequent determination of O-GlcNAc attachment sites. We have listed the strengths and limitations of each protocol to allow readers to decide which suits their system and availability of resources. These protocols include galactosyltransferase labeling, immunoblotting, using mass spectrometry based on beta-elimination followed by Michael addition with dithiothreitol, and chemoenzymatic labeling, enrichment, and detection.
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Affiliation(s)
- Stephen A Whelan
- Department of Biological Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD, USA
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Sáez ME, Martínez-Larrad MT, Ramírez-Lorca R, González-Sánchez JL, Zabena C, Martinez-Calatrava MJ, González A, Morón FJ, Ruiz A, Serrano-Ríos M. Calpain-5 gene variants are associated with diastolic blood pressure and cholesterol levels. BMC MEDICAL GENETICS 2007; 8:1. [PMID: 17227582 PMCID: PMC1783645 DOI: 10.1186/1471-2350-8-1] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/08/2006] [Accepted: 01/16/2007] [Indexed: 11/16/2022]
Abstract
Background Genes implicated in common complex disorders such as obesity, type 2 diabetes mellitus (T2DM) or cardiovascular diseases are not disease specific, since clinically related disorders also share genetic components. Cysteine protease Calpain 10 (CAPN10) has been associated with T2DM, hypertension, hypercholesterolemia, increased body mass index (BMI) and polycystic ovary syndrome (PCOS), a reproductive disorder of women in which isunlin resistance seems to play a pathogenic role. The calpain 5 gene (CAPN5) encodes a protein homologue of CAPN10. CAPN5 has been previously associated with PCOS by our group. In this new study, we have analysed the association of four CAPN5 gene variants(rs948976A>G, rs4945140G>A, rs2233546C>T and rs2233549G>A) with several cardiovascular risk factors related to metabolic syndrome in general population. Methods Anthropometric measurements, blood pressure, insulin, glucose and lipid profiles were determined in 606 individuals randomly chosen from a cross-sectional population-based epidemiological survey in the province of Segovia in Central Spain (Castille), recruited to investigate the prevalence of anthropometric and physiological parameters related to obesity and other components of the metabolic syndrome. Genotypes at the four polymorphic loci in CAPN5 gene were detected by polymerase chain reaction (PCR). Results Genotype association analysis was significant for BMI (p ≤ 0.041), diastolic blood pressure (p = 0.015) and HDL-cholesterol levels (p = 0.025). Different CAPN5 haplotypes were also associated with diastolic blood pressure (DBP) (0.0005 ≤ p ≤ 0.006) and total cholesterol levels (0.001 ≤ p ≤ 0.029). In addition, the AACA haplotype, over-represented in obese individuals, is also more frequent in individuals with metabolic syndrome defined by ATPIII criteria (p = 0.029). Conclusion As its homologue CAPN10, CAPN5 seems to influence traits related to increased risk for cardiovascular diseases. Our results also may suggest CAPN5 as a candidate gene for metabolic syndrome.
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Affiliation(s)
- María E Sáez
- Departamento de Genómica Estructural. Neocodex. Sevilla, Spain
| | | | | | | | - Carina Zabena
- Departamento de Medicina Interna II. Hospital Clínico San Carlos. Madrid, Spain
| | | | - Alejandro González
- Unidad de reproducción y genética humana. Centro Avanzado de Fertilidad (CAF). Jerez de la Frontera, Cádiz, Spain
| | | | - Agustín Ruiz
- Departamento de Genómica Estructural. Neocodex. Sevilla, Spain
| | - Manuel Serrano-Ríos
- Departamento de Medicina Interna II. Hospital Clínico San Carlos. Madrid, Spain
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Fülöp N, Zhang Z, Marchase RB, Chatham JC. Glucosamine cardioprotection in perfused rat hearts associated with increased O-linked N-acetylglucosamine protein modification and altered p38 activation. Am J Physiol Heart Circ Physiol 2007; 292:H2227-36. [PMID: 17208994 PMCID: PMC2850194 DOI: 10.1152/ajpheart.01091.2006] [Citation(s) in RCA: 90] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We have shown that, in the perfused heart, glucosamine improved functional recovery following ischemia and that this appeared to be mediated via an increase in O-linked N-acetylglucosamine (O-GlcNAc) levels on nucleocytoplasmic proteins. Several kinase pathways, specifically Akt and the mitogen-activated protein kinases (MAPKs) p38 and ERK1/2, which have been implicated in ischemic cardioprotection, have also been reported to be modified in response to increased O-GlcNAc levels. Therefore, the goals of this study were to determine the effect of ischemia on O-GlcNAc levels and to evaluate whether the cardioprotection resulting from glucosamine treatment could be attributed to changes in ERK1/2, Akt, and p38 phosphorylation. Isolated rat hearts were perfused with or without 5 mM glucosamine and were subjected to 5, 10, or 30 min of low-flow ischemia or 30 min of low-flow ischemia and 60 min of reperfusion. Glucosamine treatment attenuated ischemic contracture and improved functional recovery at the end of reperfusion. Glucosamine treatment increased flux through the hexosamine biosynthesis pathway and increased O-GlcNAc levels but had no effect on ATP levels. Glucosamine did not alter the response of either ERK1/2 or Akt to ischemia-reperfusion; however, it significantly attenuated the ischemia-induced increase in p38 phosphorylation and paradoxically increased p38 phosphorylation at the end of reperfusion. These data support the notion that O-GlcNAc may play an important role as an internal stress response and that glucosamine-induced cardioprotection may be mediated via the p38 MAPK pathway.
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Affiliation(s)
- Norbert Fülöp
- Department of Medicine, MCLM 684, University of Alabama at Birmingham, Birmingham Alabama 35294
| | - Zhenghao Zhang
- Department of Physiology, MCLM 684, University of Alabama at Birmingham, Birmingham Alabama 35294
| | - Richard B. Marchase
- Department of Cell Biology, MCLM 684, University of Alabama at Birmingham, Birmingham Alabama 35294
| | - John C. Chatham
- Department of Medicine, MCLM 684, University of Alabama at Birmingham, Birmingham Alabama 35294
- Department of Physiology, MCLM 684, University of Alabama at Birmingham, Birmingham Alabama 35294
- Department of Cell Biology, MCLM 684, University of Alabama at Birmingham, Birmingham Alabama 35294
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69
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Raman P, Krukovets I, Marinic TE, Bornstein P, Stenina OI. Glycosylation mediates up-regulation of a potent antiangiogenic and proatherogenic protein, thrombospondin-1, by glucose in vascular smooth muscle cells. J Biol Chem 2006; 282:5704-14. [PMID: 17178709 DOI: 10.1074/jbc.m610965200] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Accelerated development of atherosclerotic lesions remains the most frequent and dangerous complication of diabetes, accounting for 80% of deaths among diabetics. However, our understanding of the pathways mediating glucose-induced gene expression in vascular cells remains controversial and incomplete. We have identified an intracellular metabolic pathway activated by high glucose in human aortic smooth muscle cells that mediates up-regulation of thrombospondin-1 (TSP-1). TSP-1 is a potent antiangiogenic and proatherogenic protein that may represent an important link between diabetes and vascular complications. Using different glucose analogs and metabolites sharing distinct, limited metabolic steps with glucose, we demonstrated that activation of TSP-1 transcription is mediated by the hexosamine pathway of glucose catabolism, possibly resulting in modulation of the activity of nuclear proteins activity through their glycosylation. Specific inhibitors of glutamine: fructose 6-phosphate amidotransferase (GFAT), an enzyme controlling the hexosamine pathway, as well as direct inhibitors of protein glycosylation efficiently inhibited TSP-1 transcription and the activity of a TSP-1 promoter-reporter construct stimulated by high glucose. Overexpression of recombinant GFAT resulted in increased TSP-1 levels. Pharmacological inhibition of GFAT or protein glycosylation inhibited increased proliferation of human aortic smooth muscle cells caused by glucose. We have demonstrated that the hexosamine metabolic pathway mediates up-regulation of TSP-1 by high glucose. Our results suggest that the hexosamine pathway and intracellular glycosylation may control important steps in initiation and development of atherosclerotic lesions.
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Affiliation(s)
- Priya Raman
- Department of Molecular Cardiology, Joseph J. Jacobs Center for Thrombosis and Vascular Biology, Cleveland Clinic, Cleveland, Ohio 44195, USA
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70
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Vázquez-Dorbatt V, Maynard HD. Biotinylated glycopolymers synthesized by atom transfer radical polymerization. Biomacromolecules 2006; 7:2297-302. [PMID: 16903674 DOI: 10.1021/bm060105f] [Citation(s) in RCA: 107] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Biotinylated glycopolymers that bind to the protein streptavidin were synthesized by atom transfer radical polymerization (ATRP). Poly(methacrylate)s with pendent N-acetyl-d-glucosamines were prepared by polymerizing the protected monomer, followed by deprotection. Alternatively, the unprotected monomer was directly polymerized. Both paths provided well-defined glycopolymers with narrow molecular weight distributions (PDI = 1.07-1.23). The number-average molecular weights determined by gel permeation chromatography increased with increasing initial monomer-to-initiator ratios. The polymers were synthesized using a biotin-functionalized initiator for ATRP. Confirmation of the end group and binding to the protein streptavidin was achieved by (1)H NMR and surface plamon resonance.
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Affiliation(s)
- Vimary Vázquez-Dorbatt
- Department of Chemistry and Biochemistry and California Nanosystems Institute, University of California, Los Angeles, 607 Charles E. Young Drive East, Los Angeles, California 90095-1569, USA
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71
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Mikesh LM, Ueberheide B, Chi A, Coon JJ, Syka JEP, Shabanowitz J, Hunt DF. The utility of ETD mass spectrometry in proteomic analysis. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2006; 1764:1811-22. [PMID: 17118725 PMCID: PMC1853258 DOI: 10.1016/j.bbapap.2006.10.003] [Citation(s) in RCA: 395] [Impact Index Per Article: 21.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/05/2006] [Revised: 10/04/2006] [Accepted: 10/09/2006] [Indexed: 10/24/2022]
Abstract
Mass spectrometry has played an integral role in the identification of proteins and their post-translational modifications (PTM). However, analysis of some PTMs, such as phosphorylation, sulfonation, and glycosylation, is difficult with collision-activated dissociation (CAD) since the modification is labile and preferentially lost over peptide backbone fragmentation, resulting in little to no peptide sequence information. The presence of multiple basic residues also makes peptides exceptionally difficult to sequence by conventional CAD mass spectrometry. Here we review the utility of electron transfer dissociation (ETD) mass spectrometry for sequence analysis of post-translationally modified and/or highly basic peptides. Phosphorylated, sulfonated, glycosylated, nitrosylated, disulfide bonded, methylated, acetylated, and highly basic peptides have been analyzed by CAD and ETD mass spectrometry. CAD fragmentation typically produced spectra showing limited peptide backbone fragmentation. However, when these peptides were fragmented using ETD, peptide backbone fragmentation produced a complete or almost complete series of ions and thus extensive peptide sequence information. In addition, labile PTMs remained intact. These examples illustrate the utility of ETD as an advantageous tool in proteomic research by readily identifying peptides resistant to analysis by CAD. A further benefit is the ability to analyze larger, non-tryptic peptides, allowing for the detection of multiple PTMs within the context of one another.
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Affiliation(s)
- Leann M Mikesh
- Department of Chemistry, University of Virginia, Charlottesville, VA 22904
| | - Beatrix Ueberheide
- Department of Chemistry, University of Virginia, Charlottesville, VA 22904
| | - An Chi
- Department of Chemistry, University of Virginia, Charlottesville, VA 22904
| | - Joshua J Coon
- Department of Chemistry, University of Virginia, Charlottesville, VA 22904
| | - John E P Syka
- Department of Engineering Physics Program, University of Virginia, Charlottesville, VA 22904
- Department of Thermo Electron, San Jose, CA 95134
| | | | - Donald F Hunt
- Department of Chemistry, University of Virginia, Charlottesville, VA 22904
- Department of Pathology, Health Sciences Center, University of Virginia, Charlottesville, VA 22908
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Liu J, Marchase RB, Chatham JC. Glutamine-induced protection of isolated rat heart from ischemia/reperfusion injury is mediated via the hexosamine biosynthesis pathway and increased protein O-GlcNAc levels. J Mol Cell Cardiol 2006; 42:177-85. [PMID: 17069847 PMCID: PMC1779903 DOI: 10.1016/j.yjmcc.2006.09.015] [Citation(s) in RCA: 114] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/30/2006] [Revised: 08/31/2006] [Accepted: 09/20/2006] [Indexed: 11/29/2022]
Abstract
It has been shown that glutamine protects the heart from ischemia/reperfusion (I/R) injury; however, the mechanisms underlying this protection have not been identified. Glutamine:fructose-6-phosphate amidotransferase (GFAT) regulates the entry of glucose into the hexosamine biosynthesis pathway (HBP), and activation of this pathway has been shown to be cardioprotective. Glutamine is required for metabolism of glucose via GFAT; therefore, the goal of this study was to determine whether glutamine cardioprotection could be attributed to increased flux through the HBP and elevated levels of O-linked N-acetylglucosamine (O-GlcNAc) on proteins. Hearts from male rats were isolated and perfused with Krebs-Henseliet buffer containing 5 mM glucose, and global, no-flow ischemia was induced for 20 min followed by 60 min of reperfusion. Thirty-minute pre-treatment with 2.5 mM glutamine significantly improved functional recovery (RPP: 15.6+/-5.7% vs. 59.4+/-6.1%; p<0.05) and decreased cardiac troponin I release (25.4+/-3.0 vs. 4.7+/-1.9 ng/ml; p<0.05) during reperfusion. This protection was associated with a significant increase in the levels of protein O-GlcNAc and ATP. Pre-treatment with 80 muM azaserine, an inhibitor of GFAT, completely reversed the protection seen with glutamine and prevented the increase in protein O-GlcNAc. O-GlcNAc transferase (OGT) catalyzes the formation of O-GlcNAc, and inhibition of OGT with 5 mM alloxan also reversed the protection associated with glutamine. These data support the hypothesis that in the ex vivo perfused heart glutamine cardioprotection is due, at least in part, to enhanced flux through the HBP and increased protein O-GlcNAc levels.
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Affiliation(s)
| | | | - John C. Chatham
- Department of Cell Biology
- Department of Medicine, University of Alabama at Birmingham,
Birmingham, AL 35294
- Address correspondence to: John C. Chatham,
Department of Medicine, 684 MCLM Building, University of Alabama at Birmingham,
Birmingham, AL 35294-0005, Tel: 205 934-0240, Fax: 205 934-0950, e-mail:
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73
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Champattanachai V, Marchase RB, Chatham JC. Glucosamine protects neonatal cardiomyocytes from ischemia-reperfusion injury via increased protein-associated O-GlcNAc. Am J Physiol Cell Physiol 2006; 292:C178-87. [PMID: 16899550 DOI: 10.1152/ajpcell.00162.2006] [Citation(s) in RCA: 134] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Increased levels of protein O-linked N-acetylglucosamine (O-GlcNAc) have been shown to increase cell survival following stress. Therefore, the goal of this study was to determine whether in isolated neonatal rat ventricular myocytes (NRVMs) an increase in protein O-GlcNAcylation resulted in improved survival and viability following ischemia-reperfusion (I/R). NRVMs were exposed to 4 h of ischemia and 16 h of reperfusion, and cell viability, necrosis, apoptosis, and O-GlcNAc levels were assessed. Treatment of cells with glucosamine, hyperglycemia, or O-(2-acetamido-2-deoxy-D-glucopyranosylidene)-amino-N-phenylcarbamate(PUGNAc), an inhibitor of O-GlcNAcase, significantly increased O-GlcNAc levels and improved cell viability, as well as reducing both necrosis and apoptosis compared with untreated cells following I/R. Alloxan, an inhibitor of O-GlcNAc transferase, markedly reduced O-GlcNAc levels and exacerbated I/R injury. The improved survival with hyperglycemia was attenuated by azaserine, which inhibits glucose metabolism via the hexosamine biosynthesis pathway. Reperfusion in the absence of glucose reduced O-GlcNAc levels on reperfusion compared with normal glucose conditions and decreased cell viability. O-GlcNAc levels significantly correlated with cell viability during reperfusion. The effects of glucosamine and PUGNAc on cellular viability were associated with reduced calcineurin activation as measured by translocation of nuclear factor of activated T cells, suggesting that increased O-GlcNAc levels may attenuate I/R induced increase in cytosolic Ca(2+). These data support the concept that activation of metabolic pathways leading to an increase in O-GlcNAc levels is an endogenous stress-activated response and that augmentation of this response improves cell survival. Thus strategies designed to activate these pathways may represent novel interventions for inducing cardioprotection.
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Affiliation(s)
- Voraratt Champattanachai
- University of Alabama at Birmingham, 1530 3rd Avenue South, MCLM 684, Birmingham, AL 35294-0005, USA
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74
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Yang S, Zou LY, Bounelis P, Chaudry I, Chatham JC, Marchase RB. Glucosamine administration during resuscitation improves organ function after trauma hemorrhage. Shock 2006; 25:600-7. [PMID: 16721268 DOI: 10.1097/01.shk.0000209563.07693.db] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Stress-induced hyperglycemia is necessary for maximal rates of survival after severe hemorrhage; however, the responsible mechanisms are not clear. One consequence of hyperglycemia is an increase in hexosamine biosynthesis, which leads to increases in levels of O-linked attachment of N-acetyl-glucosamine (O-GlcNAc) on nuclear and cytoplasmic proteins. This modification has been shown to lead to improved survival of isolated cells after stress. In view of this, we hypothesized that glucosamine (GlcNH2), which more selectively increases the levels of O-GlcNAc administration after shock, will have salutary effects on organ function after trauma hemorrhage (TH). Fasted male rats that underwent midline laparotomy were bled to a mean arterial blood pressure of 40 mmHg for 90 min and then resuscitated with Ringer lactate (four times the shed blood volume). Administration of 2.5 mL of 150 mmol L GlcNH2 midway during resuscitation improved cardiac output 2-fold compared with controls that received 2.5 mL of 150 mmol L NaCl. GlcNH2 also improved perfusion of various organs systems, including kidney and brain, and attenuated the TH-induced increase in serum levels of IL-6 (902+/-224 vs. 585+/-103 pg mL) and TNF-alpha (540+/-81 vs. 345+/-110 pg mL) (values are mean+/-SD). GlcNH2 administration resulted in significant increase in protein-associated O-GlcNAc in the heart and brain after TH. Thus, GlcNH2 administered during resuscitation improves recovery from TH, as assessed by cardiac function, organ perfusion, and levels of circulating inflammatory cytokines. This protection correlates with enhanced levels of nucleocytoplasmic protein O-GlcNAcylation and suggests that increased O-GlcNAc could be the mechanism that links stress-induced hyperglycemia to improved outcomes.
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Affiliation(s)
- Shaolong Yang
- Department of Surgery, Division of Cardiovascular Disease, University of Alabama at Birmingham, Birmingham, AL 35294-0005, USA
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75
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Csiszár A. Structural and functional diversity of adaptor proteins involved in tyrosine kinase signalling. Bioessays 2006; 28:465-79. [PMID: 16615089 DOI: 10.1002/bies.20411] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Adaptors are proteins of multi-modular structure without enzymatic activity. Their capacity to organise large, temporary protein complexes by linking proteins together in a regulated and selective fashion makes them of outstanding importance in the establishment and maintenance of specificity and efficiency in all known signal transduction pathways. This review focuses on the structural and functional characterisation of adaptors involved in tyrosine kinase (TK) signalling. TK-linked adaptors can be distinguished by their domain composition and binding specificities. However, such structural classifications have proven inadequate as indicators of functional roles. A better way to understand the logic of signalling networks might be to look at functional aspects of adaptor proteins such as signalling specificity, negative versus positive contribution to signal propagation, or their position in the signalling hierarchy. All of these functions are dynamic, suggesting that adaptors have important regulatory roles rather than acting only as stable linkers in signal transduction.
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76
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Kim YH, Song M, Oh YS, Heo K, Choi JW, Park JM, Kim SH, Lim S, Kwon HM, Ryu SH, Suh PG. Inhibition of phospholipase C-beta1-mediated signaling by O-GlcNAc modification. J Cell Physiol 2006; 207:689-96. [PMID: 16538662 DOI: 10.1002/jcp.20609] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Here we report inhibition of phospholipase C-beta1 (PLC-beta1)-mediated signaling by post-translational glycosylation with beta-N-acetylglucosamine (O-GlcNAc modification). In C2C12 myoblasts, isoform-specific knock-down experiments using siRNA showed that activation of bradykinin (BK) receptor led to stimulation of PLC-beta1 and subsequent intracellular Ca2+ mobilization. In C2C12 myotubes, O-GlcNAc modification of PLC-beta1 was markedly enhanced in response to treatment with glucosamine (GlcNH2), an inhibitor of O-GlcNAase (PUGNAc) and hyperglycemia. This was associated with more than 50% inhibition of intracellular production of IP3 and Ca2+ mobilization in response to BK. Since the abundance of PLC-beta1 remained unchanged, these data suggest that O-GlcNAc modification of PLC-beta1 led to inhibition of its activity. Moreover, glucose uptake stimulated by BK was significantly blunted by treatment with PUGNAc. These data support the notion that O-GlcNAc modification negatively modulates the activity of PLC-beta1.
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Affiliation(s)
- Yun-Hee Kim
- Department of Life Science, Division of Molecular and Life Science, Pohang University of Science and Technology, Pohang, Korea
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78
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Gandy JC, Rountree AE, Bijur GN. Akt1 is dynamically modified with O-GlcNAc following treatments with PUGNAc and insulin-like growth factor-1. FEBS Lett 2006; 580:3051-8. [PMID: 16684529 PMCID: PMC2493066 DOI: 10.1016/j.febslet.2006.04.051] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2006] [Revised: 04/10/2006] [Accepted: 04/13/2006] [Indexed: 11/21/2022]
Abstract
The Ser/Thr kinase Akt1 is activated by growth factors subsequent to its phosphorylation on Thr308 and Ser473. In the present study, Akt1 was found to be constitutively modified with O-GlcNAc. Treatment of SH-SY5Y cells with O(2-acetamido-2-deoxy-D-glucopyranosylidene)amino-N-phenylcarbamate (PUGNAc), which inhibits the enzymatic removal of O-GlcNAc from proteins, increased cytosolic O-GlcNAc-Akt1 levels. Treatment of cells with insulin-like growth factor-1 (IGF-1) also increased O-GlcNAc-Akt1 levels and increased Akt1 phosphorylation. PUGNAc treatment did not attenuate IGF-1 induced Akt1 phosphorylation. These results indicate that Akt1 can be simultaneously modified with O-GlcNAc and phosphorylated. However, PUGNAc induced the nuclear accumulation of Akt1 suggesting that the O-GlcNAc-modification on Akt1 may play a role in Akt1 nuclear localization.
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Affiliation(s)
| | | | - Gautam N. Bijur
- *Corresponding author. Fax: +1 205 934 2500. E-mail address: (G.N. Bijur). 0014-5793/$32.00
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79
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Triggle CR, Howarth A, Cheng ZJ, Ding H. Twenty-five years since the discovery of endothelium-derived relaxing factor (EDRF): does a dysfunctional endothelium contribute to the development of type 2 diabetes? Can J Physiol Pharmacol 2006; 83:681-700. [PMID: 16333371 DOI: 10.1139/y05-069] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Twenty-five years ago, the discovery of endothelium-derived relaxing factor opened a door that revealed a new and exciting role for the endothelium in the regulation of blood flow and led to the discovery that nitric oxide (NO) multi-tasked as a novel cell-signalling molecule. During the next 25 years, our understanding of both the importance of the endothelium as well as NO has greatly expanded. No longer simply a barrier between the blood and vascular smooth muscle, the endothelium is now recognized as a complex tissue with heterogeneous properties. The endothelium is the source of not only NO but also numerous vasoactive molecules and signalling pathways, some of which are still not fully characterized such as the putative endothelium-derived relaxing factor. Dysfunction of the endothelium is a key risk factor for the development of macro- and microvascular disease and, by coincidence, the discovery that NO was generated in the endothelium corresponds approximately in time with the increased incidence of type 2 diabetes. Primarily linked to dietary and lifestyle changes, we are now facing a global pandemic of type 2 diabetes. Characterized by insulin resistance and hyperglycaemia, type 2 diabetes is increasingly being diagnosed in adolescents as well as children. Is there a link between dietary-related hyperglycaemic insults to the endothelium, blood flow changes, and the development of insulin resistance? This review explores the evidence for and against this hypothesis.
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Affiliation(s)
- Chris R Triggle
- School of Medical Sciences, Bundoora West Campus, RMIT University, Victoria, Australia
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80
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Cooksey RC, Pusuluri S, Hazel M, McClain DA. Hexosamines regulate sensitivity of glucose-stimulated insulin secretion in beta-cells. Am J Physiol Endocrinol Metab 2006; 290:E334-40. [PMID: 16188910 DOI: 10.1152/ajpendo.00265.2005] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Hexosamines serve a nutrient-sensing function through enzymatic O-glycosylation of proteins. We previously characterized transgenic (Tg) mice with overexpression of the rate-limiting enzyme in hexosamine production, glutamine:fructose-6-phosphate amidotransferase, in beta-cells. Animals were hyperinsulinemic, resulting in peripheral insulin resistance. Glucose tolerance deteriorated with age, and males developed diabetes. We therefore examined islet function in these mice by perifusion in vitro. Young (2-mo-old) Tg animals had enhanced sensitivity to glucose of insulin secretion. Insulin secretion was maximal at 20 mM and half maximal at 9.9 +/- 0.5 mM glucose in Tg islets compared with maximal at 30 mM and half maximal at 13.5 +/- 0.7 mM glucose in wild type (WT; P < 0.005). Young Tg animals secreted more insulin in response to 20 mM glucose (Tg, 1,254 +/- 311; WT, 425 +/- 231 pg x islet(-1) x 35 min(-1); P < 0.01). Islets from older (8-mo-old) Tg mice became desensitized to glucose, with half-maximal secretion at 16.1 +/- 0.8 mM glucose, compared with 11.8 +/- 0.7 mM in WT (P < 0.05). Older Tg mice secreted less insulin in response to 20 mM glucose (Tg, 2,256 +/- 342; WT, 3,493 +/- 367 pg x islet(-1) x 35 min(-1); P < 0.05). Secretion in response to carbachol was similar in WT and Tg at both ages. Glucose oxidation was blunted in older Tg islets. At 5 mM glucose, islet CO2 production was comparable between Tg and WT. However, WT mice increased islet CO2 production 2.7 +/- 0.4-fold in 20 mM glucose, compared with only 1.4 +/- 0.1-fold in Tg (P < 0.02). Results demonstrate that hexosamines are involved in nutrient sensing for insulin secretion, acting at least in part by modulating glucose oxidation pathways. Prolonged excess hexosamine flux results in glucose desensitization and mimics glucose toxicity.
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Affiliation(s)
- Robert C Cooksey
- Veterans Administration Medical Center and Division of Endocrinology and Metabolism, University of Utah School of Medicine, 30 N. 2030 East, Salt Lake City, UT 84132, USA
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81
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Lazarus BD, Love DC, Hanover JA. Recombinant O-GlcNAc transferase isoforms: identification of O-GlcNAcase, yes tyrosine kinase, and tau as isoform-specific substrates. Glycobiology 2006; 16:415-21. [PMID: 16434389 DOI: 10.1093/glycob/cwj078] [Citation(s) in RCA: 103] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
O-linked N-acetylglucosaminyltransferase (OGT) catalyzes the transfer of O-linked GlcNAc to serine or threonine residues of a variety of substrate proteins, including nuclear pore proteins, transcription factors, and proteins implicated in diabetes and neurodegenerative disorders. We have identified two nucleocytoplasmic isoforms of OGT (ncOGT and sOGT) and one isoform that localizes to the mitochondria (mOGT). These three isoforms contain identical catalytic regions but differ in the number of tetratricopeptide repeat motifs found at the N-terminus of each enzyme. We expressed each of these OGT isoforms in a soluble form in Escherichia coli and have used them to identify novel targets including the Src-family tyrosine kinase yes and O-GlcNAc-ase. We demonstrate that some substrate proteins, such as Nup62 and casein kinase II, are glycosylated by both ncOGT and mOGT, while others such as O-GlcNAcase and tau are specifically modified by ncOGT. The yes kinase was specifically modified by mOGT. The short isoform of OGT (sOGT) did not glycosylate any of the substrates tested, although it retains a potentially active catalytic domain. Our findings demonstrate the potential utility of recombinant OGT in identifying new targets and illustrate the necessity to examine all active isoforms of the enzyme. The identification of a tyrosine kinase and O-GlcNAcase as OGT targets suggests the potential for OGT participation in numerous signal transduction cascades.
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Affiliation(s)
- Brooke D Lazarus
- Laboratory of Cell Biology and Biochemistry, NIDDK, National Institutes of Health, Bethesda, MD 20897-0851, USA
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82
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Davidoff AJ. CONVERGENCE OF GLUCOSE- AND FATTY ACID-INDUCED ABNORMAL MYOCARDIAL EXCITATION-CONTRACTION COUPLING AND INSULIN SIGNALLING. Clin Exp Pharmacol Physiol 2006; 33:152-8. [PMID: 16445715 DOI: 10.1111/j.1440-1681.2006.04343.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
1. Myocardial insulin resistance and abnormal Ca(2+) regulation are hallmarks of hypertrophic and diabetic hearts, but deprivation of energetic substrates does not tell the whole story. Is there a link between the aetiology of these dysfunctions? 2. Diabetic cardiomyopathy is defined as phenotypic changes in the heart muscle cell independent of associated coronary vascular disease. The cellular consequences of diabetes on excitation-contraction (E-C) coupling and insulin signalling are presented in various models of diabetes in order to set the stage for exploring the pathogenesis of heart disease. 3. Excess glucose or fatty acids can lead to augmented flux through the hexosamine biosynthesis pathway (HBP). The formation of uridine 5 cent-diphosphate-hexosamines has been shown to be involved in abnormal E-C coupling and myocardial insulin resistance. 4. There is growing evidence that O-linked glycosylation (downstream of HBP) may regulate the function of cytosolic and nuclear proteins in a dynamic manner, similar to phosphorylation and perhaps involving reciprocal or synergistic modification of serine/threonine sites. 5. This review focuses on the question of whether there is a role for HBP and dynamic O-linked glycosylation in the development of myocardial insulin resistance and abnormal E-C coupling. The emerging concept that O-linked glycosylation is a regulatory, post-translational modification of cytosolic/nuclear proteins that interacts with phosphorylation in the heart is explored.
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Affiliation(s)
- Amy J Davidoff
- Department of Pharmacology, College of Osteopathic Medicine, University of New England, Biddeford, ME, USA.
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83
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Nagy T, Champattanachai V, Marchase RB, Chatham JC. Glucosamine inhibits angiotensin II-induced cytoplasmic Ca2+elevation in neonatal cardiomyocytes via protein-associatedO-linkedN-acetylglucosamine. Am J Physiol Cell Physiol 2006; 290:C57-65. [PMID: 16107505 DOI: 10.1152/ajpcell.00263.2005] [Citation(s) in RCA: 83] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We previously reported that glucosamine and hyperglycemia attenuate the response of cardiomyocytes to inositol 1,4,5-trisphosphate-generating agonists such as ANG II. This appears to be related to an increase in flux through the hexosamine biosynthesis pathway (HBP) and decreased Ca2+entry into the cells; however, a direct link between HBP and intracellular Ca2+homeostasis has not been established. Therefore, using neonatal rat ventricular myocytes, we investigated the relationship between glucosamine treatment; the concentration of UDP- N-acetylglucosamine (UDP-GlcNAc), an end product of the HBP; and the level of protein O-linked N-acetylglucosamine ( O-GlcNAc) on ANG II-mediated changes in intracellular free Ca2+concentration ([Ca2+]i). We found that glucosamine blocked ANG II-induced [Ca2+]iincrease and that this phenomenon was associated with a significant increase in UDP-GlcNAc and O-GlcNAc levels. O-(2-acetamido-2-deoxy-d-glucopyranosylidene)-amino- N-phenylcarbamate, an inhibitor of O-GlcNAcase that increased O-GlcNAc levels without changing UDP-GlcNAc concentrations, mimicked the effect of glucosamine on the ANG II-induced increase in [Ca2+]i. An inhibitor of O-GlcNAc-transferase, alloxan, prevented the glucosamine-induced increase in O-GlcNAc but not the increase in UDP-GlcNAc; however, alloxan abrogated the inhibition of the ANG II-induced increase in [Ca2+]i. These data support the notion that changes in O-GlcNAc levels mediated via increased HBP flux may be involved in the regulation of [Ca2+]ihomeostasis in the heart.
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Affiliation(s)
- Tamas Nagy
- Dept. of Cell Biology, Univ. of Alabama at Birmingham, 1530 Third Ave. South, 684 MCLM Bldg., Birmingham, AL 35294-0005, USA
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84
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Schulz R, Rassaf T, Massion PB, Kelm M, Balligand JL. Recent advances in the understanding of the role of nitric oxide in cardiovascular homeostasis. Pharmacol Ther 2005; 108:225-56. [PMID: 15949847 DOI: 10.1016/j.pharmthera.2005.04.005] [Citation(s) in RCA: 98] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2005] [Accepted: 04/15/2005] [Indexed: 02/04/2023]
Abstract
Nitric oxide synthases (NOS) are the enzymes responsible for nitric oxide (NO) generation. To date, 3 distinct NOS isoforms have been identified: neuronal NOS (NOS1), inducible NOS (NOS2), and endothelial NOS (NOS3). Biochemically, NOS consists of a flavin-containing reductase domain, a heme-containing oxygenase domain, and regulatory sites. NOS catalyse an overall 5-electron oxidation of one Nomega-atom of the guanidino group of L-arginine to form NO and L-citrulline. NO exerts a plethora of biological effects in the cardiovascular system. The basal formation of NO in mitochondria by a mitochondrial NOS seems to be one of the main regulators of cellular respiration, mitochondrial transmembrane potential, and transmembrane proton gradient. This review focuses on recent advances in the understanding of the role of enzyme and enzyme-independent NO formation, regulation of NO bioactivity, new aspects of NO on cardiac function and morphology, and the clinical impact and perspectives of these recent advances in our knowledge on NO-related pathways.
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Affiliation(s)
- R Schulz
- Institut für Pathophysiologie, Zentrum für Innere Medizin des Universitätsklinikums Essen, Germany.
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85
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86
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Guinez C, Morelle W, Michalski JC, Lefebvre T. O-GlcNAc glycosylation: a signal for the nuclear transport of cytosolic proteins? Int J Biochem Cell Biol 2005; 37:765-74. [PMID: 15694836 DOI: 10.1016/j.biocel.2004.12.001] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2004] [Indexed: 11/28/2022]
Abstract
Year 2004 marks the 20th anniversary of the discovery of O-linked N-acetylglucosamine (O-GlcNAc) by Gerald W. Hart. Despite interest for O-GlcNAc, the functions played by this single monosaccharide remain poorly understood, though numerous roles have been suggested, among which is the involvement of O-GlcNAc in the nuclear transport of cytosolic proteins. This idea was first sustained by studies on bovine serum albumin that showed that the protein could be actively carried to the nucleus when it was modified with sugars. In this paper, we will review data on this puzzling problem. We will first describe the well-established nuclear localisation signal (NLS)-dependent nuclear transport by presenting the different factors involved, and then, we will examine where and how O-GlcNAc could be involved in nuclear transport. Whereas it has been suggested that O-GlcNAc could interfere at two levels in the nuclear transport both by modifying proteins to be translocated to the nucleus and by modifying the nucleoporins of the nuclear pore complex, according to us, this second idea seems unlikely. Part of this study will also be dedicated to a relatively new concept in the nuclear transport: the role of the 70-kDa heat shock proteins (HSP70). The action of the chaperone in nuclear translocation was put forward 10 years ago, but new findings suggest that this mechanism could be linked to O-GlcNAc glycosylation.
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Affiliation(s)
- Céline Guinez
- Unité Mixte de Recherches 8576 du CNRS, Glycobiologie Structurale et Fonctionnelle, IFR 118, USTL, Bâtiment C9, 59655 Villeneuve d'Ascq, France
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87
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Stevens SM, Chung AY, Chow MC, McClung SH, Strachan CN, Harmon AC, Denslow ND, Prokai L. Enhancement of phosphoprotein analysis using a fluorescent affinity tag and mass spectrometry. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2005; 19:2157-62. [PMID: 15988732 DOI: 10.1002/rcm.2027] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
A fluorescent affinity tag (FAT) was synthesized and was utilized to selectively modify phosphorylated serine and threonine residues via beta-elimination and Michael addition chemistries in a 'one-step' reaction. This labeling technique was used for covalent modification of both phosphoproteins and phosphopeptides, allowing identification of these molecular species by fluorescence imaging after solution- or gel-based separation methods. In addition to the strong fluorescence of the rhodamine tag, a commercially available antibody can be used to enrich low-abundance post-labeled phosphopeptides present in complex mixtures. Application of this methodology to phosphorylation-site mapping has been evaluated for a phosphoprotein standard, bovine beta-casein. Initial results demonstrated low femtomole detection limits after fluorescence image analysis of FAT-labeled proteins or peptides.
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Affiliation(s)
- Stanley M Stevens
- University of Florida, Protein Chemistry Core Facility, ICBR, Gainesville, FL 32610-0156, USA.
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88
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Eichacker LA, Granvogl B, Mirus O, Müller BC, Miess C, Schleiff E. Hiding behind Hydrophobicity. J Biol Chem 2004; 279:50915-22. [PMID: 15452135 DOI: 10.1074/jbc.m405875200] [Citation(s) in RCA: 83] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Proteomics of membrane proteins is essential for the understanding of cellular function. However, mass spectrometric analysis of membrane proteomes has been less successful than the proteomic determination of soluble proteins. To elucidate the mystery of transmembrane proteins in mass spectrometry, we present a detailed statistical analysis of experimental data derived from chloroplast membranes. This approach was further accomplished by the analysis of the Arabidopsis thaliana proteome after in silico digestion. We demonstrate that both the length and the hydrophobicity of the proteolytic fragments containing transmembrane segments are major determinants for detection by mass spectrometry. Based on a comparative analysis, we discuss possibilities to overcome the problem and provide possible protocols to shift the hydrophobicity of transmembrane segment-containing peptides to facilitate their detection.
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Affiliation(s)
- Lutz A Eichacker
- Department für Biologie I, Ludwig-Maximilians Universität München, Menzinger Strasse 67, 80368 München, Germany.
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89
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Khidekel N, Ficarro SB, Peters EC, Hsieh-Wilson LC. Exploring the O-GlcNAc proteome: direct identification of O-GlcNAc-modified proteins from the brain. Proc Natl Acad Sci U S A 2004; 101:13132-7. [PMID: 15340146 PMCID: PMC516536 DOI: 10.1073/pnas.0403471101] [Citation(s) in RCA: 237] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
The covalent modification of intracellular proteins by O-linked beta-N-acetylglucosamine (O-GlcNAc) is emerging as a crucial regulatory posttranslational modification akin to phosphorylation. Numerous studies point to the significance of O-GlcNAc in cellular processes such as nutrient sensing, protein degradation, and gene expression. Despite its importance, the breadth and functional roles of O-GlcNAc are only beginning to be elucidated. Advances in our understanding will require the development of new strategies for the detection and study of O-GlcNAc-modified proteins in vivo. Herein we report the direct, high-throughput analysis of O-GlcNAc-glycosylated proteins from the mammalian brain. The proteins were identified by using a chemoenzymatic approach that exploits an engineered galactosyltransferase enzyme to selectively label O-GlcNAc proteins with a ketone-biotin tag. The tag permits enrichment of low-abundance O-GlcNAc species from complex mixtures and localization of the modification to short amino acid sequences. Using this approach, we discovered 25 O-GlcNAc-glycosylated proteins from the brain, including regulatory proteins associated with gene expression, neuronal signaling, and synaptic plasticity. The functional diversity represented by this set of proteins suggests an expanded role for O-GlcNAc in regulating neuronal function. Moreover, the chemoenzymatic strategy described here should prove valuable for identifying O-GlcNAc-modified proteins in various tissues and facilitate studies of the physiological significance of O-GlcNAc across the proteome.
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Affiliation(s)
- Nelly Khidekel
- Division of Chemistry and Chemical Engineering, California Institute of Technology, 1200 East California Boulevard, Pasadena, CA 91125, USA
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90
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Seo J, Lee KJ. Post-translational modifications and their biological functions: proteomic analysis and systematic approaches. BMB Rep 2004; 37:35-44. [PMID: 14761301 DOI: 10.5483/bmbrep.2004.37.1.035] [Citation(s) in RCA: 162] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Recently produced information on post-translational modifications makes it possible to interpret their biological regulation with new insights. Various protein modifications finely tune the cellular functions of each protein. Understanding the relationship between post-translational modifications and functional changes ("post-translatomics") is another enormous project, not unlike the human genome project. Proteomics, combined with separation technology and mass spectrometry, makes it possible to dissect and characterize the individual parts of post-translational modifications and provide a systemic analysis. Systemic analysis of post-translational modifications in various signaling pathways has been applied to illustrate the kinetics of modifications. Availability will advance new technologies that improve sensitivity and peptide coverage. The progress of "post-translatomics", novel analytical technologies that are rapidly emerging, offer a great potential for determining the details of the modification sites.
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Affiliation(s)
- Jawon Seo
- Center for Cell Signaling Research, Division of Molecular Life Sciences and College of Pharmacy, Ewha Womans University, Seoul 120-750, Korea
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91
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Kumar R, Musiyenko A, Oldenburg A, Adams B, Barik S. Post-translational generation of constitutively active cores from larger phosphatases in the malaria parasite, Plasmodium falciparum: implications for proteomics. BMC Mol Biol 2004; 5:6. [PMID: 15230980 PMCID: PMC459218 DOI: 10.1186/1471-2199-5-6] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2004] [Accepted: 07/01/2004] [Indexed: 11/16/2022] Open
Abstract
Background Although the complete genome sequences of a large number of organisms have been determined, the exact proteomes need to be characterized. More specifically, the extent to which post-translational processes such as proteolysis affect the synthesized proteins has remained unappreciated. We examined this issue in selected protein phosphatases of the protease-rich malaria parasite, Plasmodium falciparum. Results P. falciparum encodes a number of Ser/Thr protein phosphatases (PP) whose catalytic subunits are composed of a catalytic core and accessory domains essential for regulation of the catalytic activity. Two examples of such regulatory domains are found in the Ca+2-regulated phosphatases, PP7 and PP2B (calcineurin). The EF-hand domains of PP7 and the calmodulin-binding domain of PP2B are essential for stimulation of the phosphatase activity by Ca+2. We present biochemical evidence that P. falciparum generates these full-length phosphatases as well as their catalytic cores, most likely as intermediates of a proteolytic degradation pathway. While the full-length phosphatases are activated by Ca+2, the processed cores are constitutively active and either less responsive or unresponsive to Ca+2. The processing is extremely rapid, specific, and occurs in vivo. Conclusions Post-translational cleavage efficiently degrades complex full-length phosphatases in P. falciparum. In the course of such degradation, enzymatically active catalytic cores are produced as relatively stable intermediates. The universality of such proteolysis in other phosphatases or other multi-domain proteins and its potential impact on the overall proteome of a cell merits further investigation.
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Affiliation(s)
- Rajinder Kumar
- Department of Biochemistry and Molecular Biology, University of South Alabama, College of Medicine, 307 University Blvd., Mobile, Alabama, USA 36688-0002
| | - Alla Musiyenko
- Department of Biochemistry and Molecular Biology, University of South Alabama, College of Medicine, 307 University Blvd., Mobile, Alabama, USA 36688-0002
| | - Anja Oldenburg
- Department of Biochemistry and Molecular Biology, University of South Alabama, College of Medicine, 307 University Blvd., Mobile, Alabama, USA 36688-0002
| | - Brian Adams
- Department of Biochemistry and Molecular Biology, University of South Alabama, College of Medicine, 307 University Blvd., Mobile, Alabama, USA 36688-0002
| | - Sailen Barik
- Department of Biochemistry and Molecular Biology, University of South Alabama, College of Medicine, 307 University Blvd., Mobile, Alabama, USA 36688-0002
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92
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Guinez C, Lemoine J, Michalski JC, Lefebvre T. 70-kDa-heat shock protein presents an adjustable lectinic activity towards O-linked N-acetylglucosamine. Biochem Biophys Res Commun 2004; 319:21-6. [PMID: 15158436 DOI: 10.1016/j.bbrc.2004.04.144] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2004] [Indexed: 11/26/2022]
Abstract
Numerous works demonstrated that the dynamic O-GlcNAc glycosylation could protect against the proteasomal degradation by modifying the target proteins and the proteasome itself. Considering that Hsp70 is a crucial component in the quality control of protein conformation in the proteasomal pathway, we investigated the possibility that Hsp70 physically interacts with O-GlcNAc proteins through a lectinic activity. First, we demonstrate that in HepG2 cells, Hsp70 can specifically bind to O-GlcNAc residues but also is itself modified by O-GlcNAc. Second, when cells were deprived of glucose (nutrient stress), Hsp70 lectinic activity markedly increased whereas its glycosylation dramatically decreased. On the other hand, a 42 degrees C thermic stress did not affect any of these features. Lastly, the nature of O-GlcNAc modified proteins co-immunoprecipitating with Hsp70 was similar for cells submitted to the thermic and to nutrient stress. These results strongly suggest that O-GlcNAc influences protein stability through specific interaction with 70-kDa-heat shock protein members.
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Affiliation(s)
- Céline Guinez
- UMR 8576 du CNRS, IFR 118, Unité de Glycobiologie Structurale et Fonctionnelle, Bâtiment C9, Cité Scientifique, 59655 Villeneuve d'Ascq cedex, France
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93
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Huber SC, Hardin SC. Numerous posttranslational modifications provide opportunities for the intricate regulation of metabolic enzymes at multiple levels. CURRENT OPINION IN PLANT BIOLOGY 2004; 7:318-22. [PMID: 15134753 DOI: 10.1016/j.pbi.2004.03.002] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
The metabolic plasticity displayed by plants during normal development, and in response to environmental fluctuations and stressors, is essential for their growth and survival. The capacity to regulate metabolic enzymes intricately arises in part from posttranslational modifications that can affect enzymatic activity, intracellular localization, protein-protein interactions, and stability. Protein phosphorylation and thiol/disulfide redox modulation are important modifications in plants, and it is likely that O-glycosylation and S-nitrosylation will also emerge as important mechanisms. Recent advances in the field of proteomics, in particular the development of novel and specific chemistries for the detection of a diverse number of modifications, are rapidly expanding our awareness of possible modifications and our understanding of the enzymes whose functions are likely to be regulated posttranslationally.
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Affiliation(s)
- Steven C Huber
- United States Department of Agriculture-Agricultural Research Service, Photosynthesis Research Unit and Department of Plant Biology, University of Illinois, Urbana, Illinois 61801, USA.
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94
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Zachara NE, Hart GW. O-GlcNAc modification: a nutritional sensor that modulates proteasome function. Trends Cell Biol 2004; 14:218-21. [PMID: 15130576 DOI: 10.1016/j.tcb.2004.03.005] [Citation(s) in RCA: 75] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The addition of O-linked beta-N-acetylglucosamine (O-GlcNAc) to serine and threonine residues is a post-translational modification of nucleocytoplasmic proteins that is thought to act in a manner analogous to protein phosphorylation. Recent work shows that many proteins of the metazoan proteasome are modified by O-GlcNAc and that the level of glycosylation is responsive to the nutritional state of the cell. Moreover, increased glycosylation of the 19S (or PA700) regulatory subcomplex has been correlated with decreased proteasomal activity, suggesting a new model of proteasomal regulation.
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Affiliation(s)
- Natasha E Zachara
- Department of Biological Chemistry, The Johns Hopkins University Medical School, Baltimore, MD 21205-2185, USA
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95
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Lopez MF, Melov S, Johnson F, Nagulko N, Golenko E, Kuzdzal S, Ackloo S, Mikulskis A. Proteomic analysis of mitochondrial proteins. INTERNATIONAL REVIEW OF NEUROBIOLOGY 2004; 61:31-48. [PMID: 15482810 DOI: 10.1016/s0074-7742(04)61002-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/30/2023]
Affiliation(s)
- Mary F Lopez
- PerkinElmer Life and Analytical Sciences, Boston, Massachusetts 02118, USA
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