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Glyceraldehyde-3-Phosphate Dehydrogenase Restricted in Cytoplasmic Location by Viral GP5 Facilitates Porcine Reproductive and Respiratory Syndrome Virus Replication via Its Glycolytic Activity. J Virol 2021; 95:e0021021. [PMID: 34160254 DOI: 10.1128/jvi.00210-21] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Porcine reproductive and respiratory syndrome virus (PRRSV) is one of the most important endemic swine pathogens, causing enormous losses in the global swine industry. Commercially available vaccines only partially prevent or counteract the virus infection and correlated losses. PRRSV's replication mechanism has not been well understood. In this study, glyceraldehyde-3-phosphate dehydrogenase (GAPDH) was screened to bind with the viral major envelope glycoprotein 5 (GP5) after PRRSV infection. The interacting sites are located within a 13-amino-acid (aa) region (aa 93 to 105) of GP5 and at Lys227 of GAPDH. Interestingly, viral GP5 restricts the translocation of GAPDH from the cytoplasm to the nucleus. Moreover, cytoplasmic GAPDH facilitates PRRSV replication by virtue of its glycolytic activity. The results suggest that PRRSV GP5 restricts GAPDH to the nucleus and exploits its glycolytic activity to stimulate virus replication. The data provide insight into the role of GAPDH in PRRSV replication and reveal a potential target for controlling viral infection. IMPORTANCE PRRSV poses a severe economic threat to the pig industry. PRRSV GP5, the major viral envelope protein, plays an important role in viral infection, pathogenicity, and immunity. However, interactions between GP5 and host proteins have not yet been well studied. Here, we show that GAPDH interacts with GP5 through binding a 13-aa sequence (aa 93 to 105) in GP5, while GP5 interacts with GAPDH at the K277 amino acid residue of GAPDH. We demonstrate that GP5 interacts with GAPDH in the cytoplasm during PPRSV infection, inhibiting GAPDH entry into the nucleus. PRRSV exploits the glycolytic activity of GAPDH to promote viral replication. These results enrich our understanding of PRRSV infection and pathogenesis and open a new avenue for antiviral prevention and PRRSV treatment strategies.
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Sphingosine-1-phosphate promotes erythrocyte glycolysis and oxygen release for adaptation to high-altitude hypoxia. Nat Commun 2016; 7:12086. [PMID: 27417539 PMCID: PMC4947158 DOI: 10.1038/ncomms12086] [Citation(s) in RCA: 147] [Impact Index Per Article: 18.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2015] [Accepted: 05/26/2016] [Indexed: 12/19/2022] Open
Abstract
Sphingosine-1-phosphate (S1P) is a bioactive signalling lipid highly enriched in mature erythrocytes, with unknown functions pertaining to erythrocyte physiology. Here by employing nonbiased high-throughput metabolomic profiling, we show that erythrocyte S1P levels rapidly increase in 21 healthy lowland volunteers at 5,260 m altitude on day 1 and continue increasing to 16 days with concurrently elevated erythrocyte sphingonisne kinase 1 (Sphk1) activity and haemoglobin (Hb) oxygen (O2) release capacity. Mouse genetic studies show that elevated erythrocyte Sphk1-induced S1P protects against tissue hypoxia by inducing O2 release. Mechanistically, we show that intracellular S1P promotes deoxygenated Hb anchoring to the membrane, enhances the release of membrane-bound glycolytic enzymes to the cytosol, induces glycolysis and thus the production of 2,3-bisphosphoglycerate (2,3-BPG), an erythrocyte-specific glycolytic intermediate, which facilitates O2 release. Altogether, we reveal S1P as an intracellular hypoxia-responsive biolipid promoting erythrocyte glycolysis, O2 delivery and thus new therapeutic opportunities to counteract tissue hypoxia. The presence of the signalling lipid Sphingosine 1-phosphate (S1P) in erythrocytes has unclear physiological implications. Here the authors show that the S1P-generating enzyme Sphingosine kinase type 1 and its product S1P play an important role in the red blood cell adaptation to hypoxic environments in mice and humans.
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Chernyshova ES, Zaikina YS, Tsvetovskaya GA, Strokotov DI, Yurkin MA, Serebrennikova ES, Volkov L, Maltsev VP, Chernyshev AV. Influence of magnesium sulfate on HCO3/Cl transmembrane exchange rate in human erythrocytes. J Theor Biol 2016; 393:194-202. [PMID: 26780645 DOI: 10.1016/j.jtbi.2015.12.023] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2015] [Revised: 12/16/2015] [Accepted: 12/18/2015] [Indexed: 10/22/2022]
Abstract
Magnesium sulfate (MgSO4) is widely used in medicine but molecular mechanisms of its protection through influence on erythrocytes are not fully understood and are considerably controversial. Using scanning flow cytometry, in this work for the first time we observed experimentally (both in situ and in vitro) a significant increase of HCO3(-)/Cl(-) transmembrane exchange rate of human erythrocytes in the presence of MgSO4 in blood. For a quantitative analysis of the obtained experimental data, we introduced and verified a molecular kinetic model, which describes activation of major anion exchanger Band 3 (or AE1) by its complexation with free intracellular Mg(2+) (taking into account Mg(2+) membrane transport and intracellular buffering). Fitting the model to our in vitro experimental data, we observed a good correspondence between theoretical and experimental kinetic curves that allowed us to evaluate the model parameters and to estimate for the first time the association constant of Mg(2+) with Band 3 as KB~0.07mM, which is in agreement with known values of the apparent Mg(2+) dissociation constant (from 0.01 to 0.1mM) that reflects experiments on enrichment of Mg(2+) at the inner erythrocyte membrane (Gunther, 2007). Results of this work partly clarify the molecular mechanisms of MgSO4 action in human erythrocytes. The method developed allows one to estimate quantitatively a perspective of MgSO4 treatment for a patient. It should be particularly helpful in prenatal medicine for early detection of pathologies associated with the risk of fetal hypoxia.
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Affiliation(s)
- Ekaterina S Chernyshova
- Voevodsky Institute of Chemical Kinetics and Combustion, Institutskaya 3, 630090 Novosibirsk, Russia; Novosibirsk State University, Pirogova 2, 630090 Novosibirsk, Russia
| | - Yulia S Zaikina
- Medical Centre of Siberian Branch of the Russian Academy of Science, Pirogova 25, 630090 Novosibirsk, Russia
| | - Galina A Tsvetovskaya
- ANO "Center of New Medical Technologies in Akademgorodok", Pirogova 25/4, 630090 Novosibirsk, Russia; Institute of Chemical Biology and Fundamental Medicine, Lavrentiev Avenue 8, 630090 Novosibirsk, Russia
| | - Dmitry I Strokotov
- Voevodsky Institute of Chemical Kinetics and Combustion, Institutskaya 3, 630090 Novosibirsk, Russia; Novosibirsk State Medical University, Krasny Prospect 52, 630091 Novosibirsk, Russia
| | - Maxim A Yurkin
- Voevodsky Institute of Chemical Kinetics and Combustion, Institutskaya 3, 630090 Novosibirsk, Russia; Novosibirsk State University, Pirogova 2, 630090 Novosibirsk, Russia
| | - Elena S Serebrennikova
- Medical Centre of Siberian Branch of the Russian Academy of Science, Pirogova 25, 630090 Novosibirsk, Russia
| | - Leonid Volkov
- Centre de Recherches Cliniques Etienne-Le Bel, 3001 12 Av. Nord Sherbrooke loc. # 4867, Quebec, Canada J1H 5N4
| | - Valeri P Maltsev
- Voevodsky Institute of Chemical Kinetics and Combustion, Institutskaya 3, 630090 Novosibirsk, Russia; Novosibirsk State University, Pirogova 2, 630090 Novosibirsk, Russia; Novosibirsk State Medical University, Krasny Prospect 52, 630091 Novosibirsk, Russia
| | - Andrei V Chernyshev
- Voevodsky Institute of Chemical Kinetics and Combustion, Institutskaya 3, 630090 Novosibirsk, Russia; Novosibirsk State University, Pirogova 2, 630090 Novosibirsk, Russia.
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Luo GY, Sun L, Wei EX, Tan X, Liu TCY. The effects of low-intensity He-Ne laser irradiation on erythrocyte metabolism. Lasers Med Sci 2015; 30:2313-8. [PMID: 26407713 DOI: 10.1007/s10103-015-1806-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2014] [Accepted: 09/10/2015] [Indexed: 10/23/2022]
Abstract
Low-intensity laser irradiation (LILI) can improve the deformability of red blood cells (RBCs). It might be due to the LILI effects on adenosine triphosphate (ATP) level. However, ATP content may not be a valid surrogate marker for RBC deformability. The LILI effects on RBC glycolysis were studied in this paper. Hypertonic RBCs were used in this study. After 5 min irradiation with low-intensity He-Ne laser irradiation (LHNL) at 632.8 nm and 4.4 mW/cm(2), the concentration of intracellular glucose and the activities of phosphofructokinase (PFK) and glyceraldehyde-3-phosphate dehydrogenase (GAPDH) were measured, respectively. There was no significant change in intracellular glucose concentration. The activity of PFK decreased significantly, but the activity of GAPDH increased significantly. In hypertonic RBCs, LHNL irradiation may decrease the activity of energy-consuming enzymes, but increases the activity of energy-generating enzymes in glycolysis, to improve the RBC deformability.
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Affiliation(s)
- Gang-Yue Luo
- School of Life Sciences, South China Normal University, Guangzhou, 510631, China
| | - Li Sun
- Medical College, Jinan University, Guangzhou, 510632, China
| | - En-Xiu Wei
- Laboratory of Laser Sports Medicine, South China Normal University, University Town, Guangzhou, 510006, China
| | - Xiaodong Tan
- Department of Otolaryngology, Northwestern University, Chicago, IL, 60611, USA
| | - Timon Cheng-Yi Liu
- Laboratory of Laser Sports Medicine, South China Normal University, University Town, Guangzhou, 510006, China.
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Abstract
The concept of the cytosol as a space that contains discrete zones of metabolites is discussed relative to the contribution of GAPDH. GAPDH is directed to very specific cell compartments. This chapter describes the utilization of GAPDH's enzymatic function for focal demands (i.e. ATP/ADP and NAD(+)/NADH), and offers a speculative role for GAPDH as perhaps moderating local concentrations of inorganic phosphate and hydrogen ions (i.e. co-substrate and co-product of the glycolytic reaction, respectively). Where known, the structural features of the binding between GAPDH and the compartment components are discussed. The nuances, which are associated with the intracellular distribution of GAPDH, appear to be specific to the cell-type, particularly with regards to the various plasma membrane proteins to which GAPDH binds. The chapter includes discussion on the curious observation of GAPDH being localized to the external surface of the plasma membrane in a human cell type. The default perspective has been that GAPDH localization is synonymous with compartmentation of glycolytic energy. The chapter discusses GAPDH translocation to the nucleus and to non-nuclear cellular structures, emphasizing its glycolytic function. Nevertheless, it is becoming clear that alternate functions of GAPDH play a role in compartmentation, particularly in the translocation to the nucleus.
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Affiliation(s)
- Norbert W Seidler
- Department of Biochemistry, Kansas City University of Medicine and Biosciences, Kansas City, MO, USA
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Casella S, Piccione D, Ielati S, Bocchino EG, Piccione G. Sulfate influx on band 3 protein of equine erythrocyte membrane (Equus caballus) using different experimental temperatures and buffer solutions. Cell Biochem Funct 2012; 31:333-7. [PMID: 23015199 DOI: 10.1002/cbf.2904] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2012] [Revised: 08/27/2012] [Accepted: 09/06/2012] [Indexed: 11/09/2022]
Abstract
The aim of this study was to assess the anion transport in equine erythrocytes through the measurement of the sulfate uptake operating from band 3 using different experimental temperatures and buffer solutions. Blood samples of six clinically healthy horses were collected via jugular vein puncture, and an emochrome-citometric examination was performed. The blood was divided into four aliquots and by centrifugation and aspiration the plasma and buffy coat were carefully discarded. The red blood cells were washed with an isosmotic medium and centrifuged. The obtained cell suspensions were incubated with two different experimental buffer solutions (buffer A: 115 mM Na2SO4, 10 mM NaCl, 20 mM ethylenediaminetetraacetic acid, 30 mM glucose; and buffer B: 115 mM Na2SO4, 10 mM NaCl, 20 mM ethylenediaminetetraacetic acid, 30 mM MgCl2) in a water bath for 1 h at 25 °C and 37 °C. Normal erythrocytes, suspended at 3% hematocrit, were used to measure the SO4= influx by absorption spectrophotometry at 425 nm wavelength. Unpaired Student's t-test showed a statistically significant decrease (P < 0.01) of rate constants in equine erythrocytes at 25 °C versus 37 °C using both experimental buffer solutions. Comparing the buffer A with buffer B unpaired Student's t-test showed statistically lower values (P < 0.0001) for A solution versus B solution both at 25 °C and at 37 °C. The greater inhibition of SO4 (=) influx measured in equine erythrocytes indicates the increased formation of the sulfydryl bonds in band 3 and the modulation of the sulfydryl groups, culminating in the conformational changes in band 3.
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Affiliation(s)
- S Casella
- Dipartimento di Scienze Sperimentali e Biotecnologie Applicate, Sezione di Fisiologia Applicata ed Etologia Comparata. Facoltà di Medicina Veterinaria, Università degli Studi di Messina, Polo Universitario dell'Annunziata, 98168, Messina, Italy.
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Hald B, Madsen MF, Danø S, Quistorff B, Sørensen PG. Quantitative evaluation of respiration induced metabolic oscillations in erythrocytes. Biophys Chem 2008; 141:41-8. [PMID: 19162390 DOI: 10.1016/j.bpc.2008.12.008] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2008] [Revised: 12/15/2008] [Accepted: 12/20/2008] [Indexed: 11/19/2022]
Abstract
The changes in the partial pressures of oxygen and carbon dioxide (P(O(2)) and P(CO(2))) during blood circulation alter erythrocyte metabolism, hereby causing flux changes between oxygenated and deoxygenated blood. In the study we have modeled this effect by extending the comprehensive kinetic model by Mulquiney and Kuchel [P.J. Mulquiney, and P.W. Kuchel. Model of 2,3-bisphosphoglycerate metabolism in the human erythrocyte based on detailed enzyme kinetic equations: equations and parameter refinement, Biochem. J. 1999, 342, 581-596.] with a kinetic model of hemoglobin oxy-/deoxygenation transition based on an oxygen dissociation model developed by Dash and Bassingthwaighte [R. Dash, and J. Bassingthwaighte. Blood HbO(2) and HbCO(2) dissociation curves at varied O(2), CO(2), pH, 2,3-DPG and temperature levels, Ann. Biomed. Eng., 2004, 32(12), 1676-1693.]. The system has been studied during transitions from the arterial to the venous phases by simply forcing P(O(2)) and P(CO(2)) to follow the physiological values of venous and arterial blood. The investigations show that the system passively follows a limit cycle driven by the forced oscillations of P(O(2)) and is thus inadequately described solely by steady state consideration. The metabolic system exhibits a broad distribution of time scales. Relaxations of modes with hemoglobin and Mg(2+) binding reactions are very fast, while modes involving glycolytic, membrane transport and 2,3-BPG shunt reactions are much slower. Incomplete slow mode relaxations during the 60 s period of the forced transitions cause significant overshoots of important fluxes and metabolite concentrations - notably ATP, 2,3-BPG, and Mg(2+). The overshoot phenomenon arises in consequence of a periodical forcing and is likely to be widespread in nature - warranting a special consideration for relevant systems.
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Affiliation(s)
- Bjørn Hald
- Department of Biomedical Sciences, University of Copenhagen, Denmark.
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Kinoshita A, Tsukada K, Soga T, Hishiki T, Ueno Y, Nakayama Y, Tomita M, Suematsu M. Roles of hemoglobin Allostery in hypoxia-induced metabolic alterations in erythrocytes: simulation and its verification by metabolome analysis. J Biol Chem 2007; 282:10731-41. [PMID: 17289676 DOI: 10.1074/jbc.m610717200] [Citation(s) in RCA: 74] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
When erythrocytes are exposed to hypoxia, hemoglobin (Hb) stabilizes in the T-state by capturing 2,3-bisphosphoglycerate. This process could reduce the intracellular pool of glycolytic substrates, jeopardizing cellular energetics. Recent observations suggest that hypoxia-induced activation of glycolytic enzymes is correlated with their release from Band III (BIII) on the cell membrane. Based on these data, we developed a mathematical model of erythrocyte metabolism and compared hypoxia-induced differences in predicted activities of the enzymes, their products, and cellular energetics between models with and without the interaction of Hb with BIII. The models predicted that the allostery-dependent Hb interaction with BIII accelerates consumption of upstream glycolytic substrates such as glucose 6-phosphate and increases downstream products such as phosphoenolpyruvate. This prediction was consistent with metabolomic data from capillary electrophoresis mass spectrometry. The hypoxia-induced alterations in the metabolites resulted from acceleration of glycolysis, as judged by increased conversion of [(13)C]glucose to [(13)C]lactate. The allostery-dependent interaction of Hb with BIII appeared to contribute not only to maintenance of energy charge but also to further synthesis of 2,3-bisphosphoglycerate, which could help sustain stabilization of T-state Hb during hypoxia. Furthermore, such an activation of glycolysis was not observed when Hb was stabilized in R-state by treating the cells with CO. These results suggest that Hb allostery in erythrocytes serves as an O(2)-sensing trigger that drives glycolytic acceleration to stabilize intracellular energetics and promote the ability to release O(2) from the cells.
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Affiliation(s)
- Ayako Kinoshita
- Institute for Advanced Biosciences, Keio University, Tsuruoka, Yamagata 997-0017, Japan
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Abstract
Previous work has shown that GAPDH (glyceraldehyde-3-phosphate dehydrogenase), aldolase, PFK (phosphofructokinase), PK (pyruvate kinase) and LDH (lactate dehydrogenase) assemble into a GE (glycolytic enzyme) complex on the inner surface of the human erythrocyte membrane. In an effort to define the molecular architecture of this complex, we have undertaken to localize the binding sites of these enzymes more accurately. We report that: (i) a major aldolase-binding site on the erythrocyte membrane is located within N-terminal residues 1-23 of band 3 and that both consensus sequences D6DYED10 and E19EYED23 are necessary to form a single enzyme-binding site; (ii) GAPDH has two tandem binding sites on band 3, located in residues 1-11 and residues 12-23 respectively; (iii) a PFK-binding site resides between residues 12 and 23 of band 3; (iv) no GEs bind to the third consensus sequence (residues D902EYDE906) at the C-terminus of band 3; and (v) the LDH- and PK-binding sites on the erythrocyte membrane do not reside on band 3. Taken together, these results argue that band 3 provides a nucleation site for the GE complex on the human erythrocyte membrane and that other components near band 3 must also participate in organizing the enzyme complex.
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Affiliation(s)
- Haiyan Chu
- Chemistry Department, Purdue University, 560 Oval Drive, West Lafayette, IN 47907, U.S.A
| | - Philip S. Low
- Chemistry Department, Purdue University, 560 Oval Drive, West Lafayette, IN 47907, U.S.A
- To whom correspondence should be addressed (email )
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Raikar LS, Vallejo J, Lloyd PG, Hardin CD. Overexpression of caveolin-1 results in increased plasma membrane targeting of glycolytic enzymes: The structural basis for a membrane associated metabolic compartment. J Cell Biochem 2006; 98:861-71. [PMID: 16453288 DOI: 10.1002/jcb.20732] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Although membrane-associated glycolysis has been observed in a variety of cell types, the mechanism of localization of glycolytic enzymes to the plasma membrane is not known. We hypothesized that caveolin-1 (CAV-1) serves as a scaffolding protein for glycolytic enzymes and may play a role in the organization of cell metabolism. To test this hypothesis, we over-expressed CAV-1 in cultured A7r5 (rat aorta vascular smooth muscle; VSM) cells. Confocal immunofluorescence microscopy was used to study the distribution of phosphofructokinase (PFK) and CAV-1 in the transfected cells. Areas of interest (AOI) were analyzed in a central Z-plane across the cell transversing the perinuclear region. To quantify any shift in PFK localization resulting from CAV-1 over-expression, we calculated a periphery to center (PC) index by taking the average of the two outer AOIs from each membrane region and dividing by the central one or two AOIs. We found the PC index to be 1.92 +/- 0.57 (mean +/- SEM, N = 8) for transfected cells and 0.59 +/- 0.05 (mean +/- SEM, N = 11) for control cells. Colocalization analysis demonstrated that the percentage of PFK associated with CAV-1 increased in transfected cells compared to control cells. The localization of aldolase (ALD) was also shifted towards the plasma membrane (and colocalized with PFK) in CAV-1 over-expressing cells. These results demonstrate that CAV-1 creates binding sites for PFK and ALD that may be of higher affinity than those binding sites localized in the cytoplasm. We conclude that CAV-1 functions as a scaffolding protein for PFK, ALD and perhaps other glycolytic enzymes, either through direct interaction or accessory proteins, thus contributing to compartmented metabolism in vascular smooth muscle.
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Affiliation(s)
- Leena S Raikar
- Department of Medical Pharmacology and Physiology, University of Missouri, Columbia, Missouri 65212, USA
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Szemraj J, Sobolewska B, Gulczynska E, Wilczynski J, Zylinska L. Magnesium sulfate effect on erythrocyte membranes of asphyxiated newborns. Clin Biochem 2005; 38:457-64. [PMID: 15820777 DOI: 10.1016/j.clinbiochem.2005.02.005] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2004] [Revised: 02/09/2005] [Accepted: 02/16/2005] [Indexed: 11/25/2022]
Abstract
OBJECTIVES Magnesium sulfate has been recognized as a neuroprotective agent against hypoxia-ischemia, mainly by the protection from the excitotoxicity associated with increased glutamate concentration. However, the mechanism of MgSO4 action is not fully understood and is considerably controversial. DESIGN AND METHODS During the 2 first hours of life, the asphyxiated full-term newborns were treated intravenously with one dose of MgSO4 250 mg/kg body weight. At birth, after 6 and 48 h of life the activity of ATP-dependent enzymes in erythrocyte membranes: Mg2+-ATPase, Ca2+-ATPase, protein kinases A and C, were determined. Using monoclonal antibodies, the band 3 and its phosphotyrosine level were also assayed. RESULTS The time-dependent decrease of Ca2+-ATPase activity was detected in untreated newborns, whereas MgSO4 prevented this reduction. After 48 h, protein kinases activities differed in MgSO4-treated and untreated groups. Magnesium therapy increased the amount of band 3 and diminished proteolytic degradation of this protein. CONCLUSION Our results demonstrated, for the first time, that magnesium sulfate treatment significantly altered the activities of some important enzymes in erythrocyte membrane from asphyxiated newborns. It also reduced the post-asphyxial damages of membrane compounds. These data may partly explain the molecular mechanisms of MgSO4 action in asphyxiated newborns.
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Affiliation(s)
- Janusz Szemraj
- Department of Molecular Neurochemistry, Medical University of Lodz, 6/8 Mazowiecka Str, 92-215 Lodz, Poland
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Nakayama Y, Kinoshita A, Tomita M. Dynamic simulation of red blood cell metabolism and its application to the analysis of a pathological condition. Theor Biol Med Model 2005; 2:18. [PMID: 15882454 PMCID: PMC1142344 DOI: 10.1186/1742-4682-2-18] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2004] [Accepted: 05/09/2005] [Indexed: 02/06/2023] Open
Abstract
Background Cell simulation, which aims to predict the complex and dynamic behavior of living cells, is becoming a valuable tool. In silico models of human red blood cell (RBC) metabolism have been developed by several laboratories. An RBC model using the E-Cell simulation system has been developed. This prototype model consists of three major metabolic pathways, namely, the glycolytic pathway, the pentose phosphate pathway and the nucleotide metabolic pathway. Like the previous model by Joshi and Palsson, it also models physical effects such as osmotic balance. This model was used here to reconstruct the pathology arising from hereditary glucose-6-phosphate dehydrogenase (G6PD) deficiency, which is the most common deficiency in human RBC. Results Since the prototype model could not reproduce the state of G6PD deficiency, the model was modified to include a pathway for de novo glutathione synthesis and a glutathione disulfide (GSSG) export system. The de novo glutathione (GSH) synthesis pathway was found to compensate partially for the lowered GSH concentrations resulting from G6PD deficiency, with the result that GSSG could be maintained at a very low concentration due to the active export system. Conclusion The results of the simulation were consistent with the estimated situation of real G6PD-deficient cells. These results suggest that the de novo glutathione synthesis pathway and the GSSG export system play an important role in alleviating the consequences of G6PD deficiency.
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Affiliation(s)
- Yoichi Nakayama
- Institute for Advanced Biosciences, Keio University, Tsuruoka, 997-0017, Japan
| | - Ayako Kinoshita
- Institute for Advanced Biosciences, Keio University, Tsuruoka, 997-0017, Japan
| | - Masaru Tomita
- Institute for Advanced Biosciences, Keio University, Tsuruoka, 997-0017, Japan
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Vallejo J, Hardin CD. Expression of caveolin-1 in lymphocytes induces caveolae formation and recruitment of phosphofructokinase to the plasma membrane. FASEB J 2005; 19:586-7. [PMID: 15665033 DOI: 10.1096/fj.04-2380fje] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Compartmentation of carbohydrate metabolism has been shown in a wide range of tissues including reports of one compartment of glycolysis associated with the plasma membrane of cells. However, only in the erythrocyte has the physical basis for plasma membrane-associated glycolytic pathway been established. We have previously found that phosphofructokinase (PFK) appeared to colocalize with the fairly ubiquitous plasma membrane protein caveolin-1 (CAV-1), consistent with a role for CAV-1 as an anchor for glycolysis to the plasma membrane. To test the hypothesis that CAV-1 functions as a scaffolding protein for PFK, we transfected human lymphocytes (a cell without CAV-1 expression) with human CAV-1 cDNA. We demonstrate that expression of CAV-1 in lymphocytes results in the formation of caveolae at the plasma membrane and affects the subcellular localization of PFK by recruiting PFK to the plasma membrane. Targeting of PFK by CAV-1 also was validated by the significant colocalization between the proteins after transfection, which resulted in a correlation of 0.97 +/- 0.004 between the two fluorophores. This finding is significant in as much as it illustrates the CAV-1 feasibility of generating binding sites for glycolytic enzymes on the plasma membrane. We therefore conclude that CAV-1 functions as a scaffolding protein for PFK and that this may contribute to the elucidation of the basis for carbohydrate compartmentation to the plasma membrane in a wide variety of cell types.
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Affiliation(s)
- Johana Vallejo
- Department of Medical Pharmacology and Physiology, University of Missouri, Columbia, MO 65212, USA
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Ding Y, Jiang W, Su Y, Zhou H, Zhang Z. Expression and purification of recombinant cytoplasmic domain of human erythrocyte band 3 with hexahistidine tag or chitin-binding tag in Escherichia coli. Protein Expr Purif 2004; 34:167-75. [PMID: 15003247 DOI: 10.1016/j.pep.2003.10.019] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2003] [Revised: 10/17/2003] [Indexed: 11/30/2022]
Abstract
The cytoplasmic domain of erythrocyte band 3 (cdb3) serves as a center of membrane organization in the erythrocytes by its interaction with multiple proteins including ankyrin, protein 4.1, protein 4.2, hemoglobin, and several glycolytic enzymes. In this paper, human cdb3 was cloned into three different expression vectors controlled by T7 polymerase promoter and induced with isopropyl beta-D-thiogalactopyranoside in Escherichia coli. Two of the fusion proteins containing hexahistidine tag in the N-terminal or C-terminal were purified by immobilized metal affinity column chromatography. The third recombinant cdb3 containing the affinity chitin-binding tag was purified using chitin beads followed by specific self-cleavage, which released cdb3 according to the mechanism of protein splicing. The molecular weights of purified recombinant proteins were verified by mass spectrometry. The pH-dependent properties of the intrinsic tryptophan fluorescence of the three kinds of recombinant cdb3 were compared with that of the cdb3 extracted from the erythrocytes, showing that there were no significant differences between them. Using pull-down assay combined with Western blot analysis, the interaction between recombinant cdb3 and protein 4.2 C3 fragment was verified. These demonstrated that the recombinant proteins were both structurally and functionally active. The typical yields of cdb3 purified with hexahistidine tag in the N-terminal, C-terminal, and cleaved from chitin bead were 10.6, 9.6, and 1.5 mg from 1L culture medium, respectively.
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Affiliation(s)
- Yu Ding
- Department of Physiology and Biophysics, School of Life Sciences, Fudan University, Shanghai 200433, China
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Tziatzios C, Schubert D, Lotz M, Gundogan D, Betz H, Schägger H, Haase W, Duong F, Collinson I. The bacterial protein-translocation complex: SecYEG dimers associate with one or two SecA molecules. J Mol Biol 2004; 340:513-24. [PMID: 15210351 DOI: 10.1016/j.jmb.2004.04.076] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2004] [Revised: 04/26/2004] [Accepted: 04/30/2004] [Indexed: 11/25/2022]
Abstract
In bacteria, the Sec-protein transport complex facilitates the passage of most secretory and membrane proteins across and into the plasma membrane. The core complex SecYEG forms the protein channel and engages either ribosomes or the ATPase SecA, which drive translocation of unfolded polypeptide chains through the complex and into the periplasmic space. Escherichia coli SecYEG forms dimers in membranes, but in detergent solution the population of these dimers is low. However, we find that stable dimers can be assembled by the addition of a monoclonal antibody. Normally, a stable SecYEG-SecA complex can only form on isolated membranes or on reconstituted proteo-liposomes. The antibody-stabilised SecYEG dimer binds one SecA molecule in detergent solution. In the presence of AMPPNP, a non-hydrolysable analogue of ATP, a complex forms containing one antibody and two each of SecYEG and SecA. SecYEG monomers or tetramers do not associate to a significant degree with SecA. The observed variability in the stoichiometry of SecYEG and SecA association and its nucleotide modulation may be important and necessary for the protein translocation reaction.
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Affiliation(s)
- Christos Tziatzios
- Institute für Biophysik, JWG-Universität, 60590 Frankfurt am Main, Germany
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