Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:2.5.1.18 (glutathione S-transferase)
 22,582 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We investigated the effects of anoxia (8 h) and different periods of reoxygenation (20 and 40 min) on the oxidative balance in anterior and posterior gills of the crab Chasmagnathus granulata. Enzyme activity of catalase and GST was increased in the gills of the animals submitted to anoxia, and SOD activity was decreased. These enzymes returned approximately to control levels during the anoxia recovery time. These results demonstrated enzyme activities change with variations in environmental oxygen levels. The posterior gills showed a higher antioxidant enzyme activity than anterior gills. In the gills, there were no changes in the non-enzymatic antioxidant system (TRAP) during anoxia. On the other hand, during anoxia recovery, an increase of TRAP in both gills was observed. Anoxia does not change lipid peroxidation (TBARS) in the gills. During anoxia recuperation, an increase in levels of TBARS was observed. Thus the results demonstrate that C. granulata has a similar strategy of preparation for oxidative stress as observed in other intertidal species, enabling the crabs to survive in an environment with extreme variations in physical and chemical characteristics, such as salt marshes.
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PMID:Effects of environmental anoxia and different periods of reoxygenation on oxidative balance in gills of the estuarine crab Chasmagnathus granulata. 1562 9

Latency of Epstein-Barr virus (EBV) is maintained by the transmembrane protein latent membrane protein (LMP) 2A, which mimics the B-cell receptor (BCR) and perturbs BCR signaling. LMP2A contains a cytoplasmic N-terminal domain composed of 119 amino acids, which provides signals that are responsible for the association with various signal molecules, resulting in negative regulation of B-cell signaling and the EBV lytic cycle. In the present study, to obtain N-terminal domain of LMP2A (LMP2A NTD, 13 kDa) in Escherichia coli for structural analysis, a strategy for obtaining the unfused form of LMP2A NTD without any fusion partners was proposed. Recombinant LMP2A NTD has previously been expressed using the GST fusion system in E. coli [Virology 268 (2000) 178, J. Virol. 71 (1997) 4752, Mol. Cell. Biol. 20 (2000) 8526]. However, we were unable to obtain untagged LMP2A NTD from this construct because of rapid proteolysis by thrombin. To overcome the proteolysis by thrombin, C-terminal His-tagged LMP2A NTD and intein-fused LMP2A NTD were prepared. As a result, LMP2A NTD without a fusion partner could be successfully obtained using non-enzymatic cleavage. The secondary structure of the recombinant LMP2A NTD was analyzed using circular dichroism. In aqueous solution, LMP2A NTD adopts an unordered structure, which was not affected by varying pH and salt concentration. In addition, any secondary structural components of LMP2A NTD were not induced in the membrane-mimicking environments, suggesting that LMP2A NTD may intrinsically have a random coil-like structure. The biological activity of recombinant LMP2A NTD was monitored by chemical shift perturbation in HSQC spectra of LMP2A NTD with or without WW domains, which result supports that the structural change induced by WW domains is restricted within narrow region.
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PMID:Expression and characterization of N-terminal domain of Epstein-Barr virus latent membrane protein 2A in Escherichia coli. 1580 16

Transgenic cotton (Gossypium hirsutum L.) lines expressing the tobacco glutathione S-transferase (GST) Nt107 were evaluated for tolerance to chilling, salinity, and herbicides, antioxidant enzyme activity, antioxidant compound levels, and lipid peroxidation. Although transgenic seedlings exhibited ten-fold and five-fold higher GST activity under normal and salt-stress conditions, respectively, germinating seedlings did not show improved tolerance to salinity, chilling conditions, or herbicides. Glutathione peroxidase (GPX) activity in transgenic seedlings was 30% to 60% higher under normal conditions, but was not different than GPX activity in wild-type seedlings under salt-stress conditions. Glutathione reductase, superoxide dismutase, ascorbate peroxidase, and monodehydroascorbate reductase activities were not increased in transgenic seedlings under salt-stress conditions, while dehydroascorbate reductase activity was decreased in transgenic seedlings under salt-stress conditions. Transgenic seedlings had 50% more oxidized glutathione when exposed to salt stress. Ascorbate levels were not increased in transgenic seedlings under salt-stress conditions. Malondialdehyde content in transgenic seedlings was nearly double that of wild-type seedlings under normal conditions and did not increase under salt-stress conditions. These results show that expression of Nt107 in cotton does not provide adequate protection against oxidative stress and suggests that the endogenous antioxidant system in cotton may be disrupted by the expression of the tobacco GST.
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PMID:Transgenic cotton (Gossypium hirsutum L.) seedlings expressing a tobacco glutathione S-transferase fail to provide improved stress tolerance. 1582 6

In yeast and mammalian systems, it is well established that transcriptional down-regulation by DNA-binding repressors involves core histone deacetylation, mediated by their interaction within a complex containing histone deacetylase (e.g. HDA1), as well as various other proteins (e.g. SIN3, SAP18, SAP30, and RbAp46). Here we identify that a Arabidopsis thaliana gene related in sequence to SAP18, designated AtSAP18, functions in transcription regulation in plants subjected to salt stress. The AtSAP18 loss- of-function mutant is more sensitive to NaCl, and is impaired in chlorophyll synthesis as compared to the wild-type. Using GST pull-down, two-hybrid, and transient transcription assays, we have characterized SAP18 and HDA1 orthologues and provide evidence that SAP18 and HDA1 function as transcriptional repressors. We further demonstrate that they associate with Ethylene-Responsive Element binding Factors (ERFs) to create a hormone-sensitive multimeric repressor complex under conditions of environmental stress. Our results indicate that AtSAP18 functions to link the HDA complex to transcriptional repressors that are bound to chromatin in a sequence-specific manner, thereby providing the specificity of signal transduction accompanying transcriptional repression under stress conditions.
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PMID:AtSAP18, an orthologue of human SAP18, is involved in the regulation of salt stress and mediates transcriptional repression in Arabidopsis. 1642 62

Intracellular Ca2+ signals are transduced by the binding of Ca2+ to sensor proteins, which subsequently modify the activity of their target proteins. Identification of these target proteins is, therefore, important for an understanding of cellular signalling processes. We have investigated the binding partners of four EF-hand Ca2+-binding proteins. Three proteins of the neuronal calcium sensor (NCS) family, hippocalcin, NCS-1 and neurocalcin delta were prepared as N-terminally tagged GST fusion proteins, and the less closely related protein L-CaBP1 was prepared in both N- and C-terminally tagged forms, the latter requiring generation of a new vector. Immobilised fusion proteins were used to purify binding partners from bovine brain cytosol and membrane extracts in the presence of 1 microM free Ca2+. Bound proteins were eluted with Ca2+-free and high-salt buffers and eluted proteins were identified by MALDI-MS and Western blotting. New protein targets detected included ARF1, Ca2+-dependent activator protein for secretion 1, cyclic nucleotide 3',5'-phosphodiesterase, the vacuolar ATPase, AP1 and AP2 complexes and the type I TGF-beta receptor. While certain of these interactions occurred with more than one of the Ca2+-binding proteins, others were found to be specific targets for particular Ca2+ sensors, and many of these did not overlap with known calmodulin-binding proteins. These findings provide new clues to the functional roles of the neuronal calcium sensor proteins.
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PMID:Analysis of the interacting partners of the neuronal calcium-binding proteins L-CaBP1, hippocalcin, NCS-1 and neurocalcin delta. 1647 Jun 52

Polyamines (PAs), such as putrescine, spermidine, and spermine, are present in all living organism and implicate in a wide range of cellular physiological processes. We have used transgenic technology in an attempt to evaluate their potential for mitigating the adverse effects of several abiotic stresses in plants. Sense construct of full-length cDNA for S-adenosylmethionine decarboxylase (SAMDC), a key enzyme in PA biosynthesis, from carnation (Dianthus caryophyllus L.) flower was introduced into tobacco (Nicotiana tabacum L.) by Agrobacterium tumefaciens-mediated transformation. Several transgenic lines overexpressing SAMDC gene under the control of cauliflower mosaic virus 35S promoter accumulated soluble total PAs by 2.2 (S16-S-4) to 3.1 (S16-S-1) times than wild-type plants. The transgenic tobacco did not show any difference in organ phenotype compared to the wild-type. The number and weight of seeds increased, and net photosynthetic rate also increased in transgenic plants. Stress-induced damage was attenuated in these transgenic plants, in the symptom of visible yellowing and chlorophyll degradation after all experienced stresses such as salt stress, cold stress, acidic stress, and abscisic acid treatment. H2O2-induced damage was attenuated by spermidine treatment. Transcripts for antioxidant enzymes (ascorbate peroxidase, manganase superoxide dismutase, and glutathione S-transferase) in transgenic plants and GUS activity transformed with SAMDC promoter::GUS fusion were induced more significantly by stress treatment, compared to control. These results that the transgenic plants with sense SAMDC cDNA are more tolerant to abiotic stresses than wild-type plants suggest that PAs may play an important role in contributing stress tolerance in plants.
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PMID:Overexpression of carnation S-adenosylmethionine decarboxylase gene generates a broad-spectrum tolerance to abiotic stresses in transgenic tobacco plants. 1664 82

In coastal areas, the application of pyrethroid insecticides and the resulting sediment residues pose a potential threat to marine benthic ecosystems. Pyrethroids cause acute toxicity and exhibit a wide range of sublethal effects on fish and crustaceans when exposure is aqueous. Fiddler crabs that inhabit salt marsh sediment are sensitive to sediment-associated pollutants and serve as a sentinel species for xenobiotic exposure. We exposed adult U. pugnax to salt marsh sediment spiked with different 60% trans/40% cis permethrin concentrations for 96 h, and evaluated changes in oxygen consumption rate, hemolymph osmolarity, and glutathione S-transferase activity (GST) following exposure. Marsh sediment was not lethal to U. pugnax at permethrin concentrations of 100-10,000 microg/kg. Sediment-bound permethrin had no significant effect on respiration and osmoregulation. Exposure caused an induction of hepatopancreas GST in a dose-dependent manner. Gill and midgut tissues showed induction at permethrin concentrations at 10,000 microg/kg. We conclude that short term exposure to permethrin-contaminated sediment does not pose a significant threat to this species or impact respiration and osmoregulation. Furthermore, increased GST activity allows us to evaluate this enzyme's induction as a generalist biomarker for sediment-bound pyrethroid exposures.
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PMID:No acute toxicity to Uca pugnax, the mud fiddler crab, following a 96-h exposure to sediment-bound permethrin. 1821 39

The in vitro aggregation of the model GST-GFP fusion protein was induced by several effectors, including those mimicking variations occurring under cell stress conditions. In particular, we examined the effects of thermal treatments, redox state and pH variations, salt addition, and freezing and thawing cycles. The resulting aggregates displayed different morphologies as seen by electron microscopy, and different secondary and tertiary structures, as indicated by Fourier transform infrared spectroscopy and fluorescence. Therefore, proteins can be forced to undergo multiple aggregation pathways that lead to assemblies with different molecular structures and, possibly, specific physiological and pathological roles. In conclusion, great caution should be taken in inferring conclusions on protein aggregation and disaggregation in vivo from results obtained using aggregates produced under non-physiological perturbations.
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PMID:Physical and chemical perturbations induce the formation of protein aggregates with different structural features. 1822 22

Recent studies have identified a novel family of oxidized phosphatidylcholines (oxPC(CD36)) that serve as highly specific ligands for scavenger receptor CD36. oxPC(CD36) accumulate in vivo and mediate macrophage foam cell formation as well as promote platelet hyper-reactivity in hyperlipidemia via CD36. The structural basis of oxPC(CD36) binding to CD36 has not been elucidated. We used liquid-phase binding to glutathione S-transferase fusion proteins containing various regions of CD36 to initially identify the region spanning CD36 amino acids 157-171 to contain a major binding site for oxPC(CD36). A bell-shaped pH profile and salt concentration dependence suggest an electrostatic mechanism of the binding. Two conserved, positively charged amino acids in the region 157-171 (lysines at positions 164 and 166) were identified as critical for oxPC(CD36) and oxidized low density lipoprotein (oxLDL) binding to CD36. Lysine neutralization with chemical modifier or site-directed mutagenesis of lysine 164/166 to alanine or glutamate, but not to arginine, abolished binding. Cells expressing full-length CD36 with mutated lysines (164 and 166) failed to recognize oxPC(CD36) and oxLDL. Synthetic peptides mimicking the CD36 binding site, but not mutated or scrambled peptides, effectively prevented: (i) oxLDL binding to CD36, (ii) macrophage foam cell formation induced by oxLDL, and (iii) platelet activation by oxPC(CD36). These data indicate that CD36 (160-168) represents the core of the oxPC(CD36) binding site with lysines 164/166 being indispensable for the binding.
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PMID:Mapping and characterization of the binding site for specific oxidized phospholipids and oxidized low density lipoprotein of scavenger receptor CD36. 1824 80

Two cysteine proteinase inhibitors (cystatins) from Arabidopsis thaliana, designated AtCYSa and AtCYSb, were characterized. Recombinant GST-AtCYSa and GST-AtCYSb were expressed in Escherichia coli and purified. They inhibit the catalytic activity of papain, which is generally taken as evidence for cysteine proteinase inhibitor function. Northern blot analyses showed that the expressions of AtCYSa and AtCYSb gene in Arabidopsis cells and seedlings were strongly induced by multiple abiotic stresses from high salt, drought, oxidant, and cold. Interestingly, the promoter region of AtCYSa gene contains a dehydration-responsive element (DRE) and an abscisic acid (ABA)-responsive element (ABRE), which identifies it as a DREB1A and AREB target gene. Under normal conditions, AtCYSa was expressed in 35S: DREB1A and 35S: AREB1 plants at a higher level than in WT plants, while AtCYSa gene was expressed in 35S: DREB2A plants at the same level as in WT plants. Under stress conditions (salt, drought and cold), AtCYSa was expressed more in all three transgenic plants than in WT plants. Over-expression of AtCYSa and AtCYSb in transgenic yeast and Arabidopsis plants increased the resistance to high salt, drought, oxidative, and cold stresses. Taken together, these data raise the possibility of using AtCYSa and AtCYSb to genetically improve environmental stresses tolerance in plants.
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PMID:Two cysteine proteinase inhibitors from Arabidopsis thaliana, AtCYSa and AtCYSb, increasing the salt, drought, oxidation and cold tolerance. 1852 28


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