Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: 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)

The bph locus of Pseudomonas sp. LB400, encoding biphenyl/polychlorinated biphenyl (PCB) degradation, contains a region of about 3.5 kb of hitherto unknown function, between bphC and bphD. This DNA segment has now been characterized. Four structural genes have been located and identified by a combination of expression cloning, enzyme activity tests and DNA sequencing. The region contains four closely spaced cistrons (bphKHJI) encoding a glutathione S-transferase (GST), a 2-hydroxypenta-2,4-dienoate hydratase, an acetaldehyde dehydrogenase (acylating) and a 4-hydroxy-2-oxovalerate aldolase, respectively. The latter three are enzymes required for conversion of the aliphatic end product of bphABCD-encoded catabolism of biphenyls to Krebs cycle intermediates. The discovery of these genes provides a rationale for growth of the strain on chlorinated biphenyls which yield chlorinated benzoates as dead-end metabolites. The sequences of the enzymes involved are 54-71% identical to those of homologous enzymes encoded by the dmp and xyl operons. The role of the GST in the degradation of biphenyls is less clear, but since it was found to contain, in the putative xenobiotic substrate-binding domain, a region which shares about 29% of identical amino acids with a bacterial tetrachlorohydroquinone dehalogenase, it may be involved in dehalogenation of PCB-degradative intermediates.
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PMID:The biphenyl/polychlorinated biphenyl-degradation locus (bph) of Pseudomonas sp. LB400 encodes four additional metabolic enzymes. 802 64

We previously identified human CAP, a homolog of the yeast adenylyl cyclase-associated protein. Previous studies suggest that the N-terminal and C-terminal domains of CAP have distinct functions. We have explored the interactions of human CAP with various proteins. First, by performing yeast two-hybrid screens, we have identified peptides from several proteins that interact with the C-terminal and/or the N-terminal domains of human CAP. These peptides include regions derived from CAP and BAT3, a protein with unknown function. We have further shown that MBP fusions with these peptides can associate in vitro with the N-terminal or C-terminal domains of CAP fused to GST. Our observations indicate that CAP contains regions in both the N-terminal and C-terminal domains that are capable of interacting with each other or with themselves. Furthermore, we found that myc-epitope-tagged CAP coimmunoprecipitates with HA-epitope-tagged CAP from either yeast or mammalian cell extracts. Similar results demonstrate that human CAP can also interact with human CAP2. We also show that human CAP interacts with actin, both by the yeast two-hybrid test and by coimmunoprecipitation of epitope-tagged CAP from yeast or mammalian cell extracts. This interaction requires the C-terminal domain of CAP, but not the N-terminal domain. Thus CAP appears to be capable of interacting in vivo with other CAP molecules, CAP2, and actin. We also show that actin co-immunoprecipitates with HA-CAP2 from mammalian cell extracts.
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PMID:Mammalian CAP interacts with CAP, CAP2, and actin. 876 50

Protein tyrosine phosphatase 1B (PTP1B) is a protein tyrosine phosphatase of unknown function, although increasing evidence supports a role for this phosphatase in insulin action. We have investigated the interaction of PTP1B with the insulin receptor using a PTP1B glutathione S-transferase (GST) fusion protein with a point mutation in the enzyme's catalytic domain. This fusion protein is catalytically inactive, but the phosphatase's phosphotyrosine binding site is maintained. The activated insulin receptor was precipitated from purified receptor preparations and whole-cell lysates by the inactive PTP1B-GST, demonstrating a direct association between the insulin receptor and PTP1B. A p120 of unknown identity was also precipitated from whole-cell lysates by the PTP1B fusion protein, but IRS-1 (pp185) was not. A catalytically inactive [35S]PTP1B-fusion protein bound directly to immobilized insulin receptor kinase domains and was displaced in a concentration-dependent manner. Finally, tyrosine-phosphorylated PTP1B was precipitated from whole-cell lysates by an anti-insulin receptor antibody after insulin stimulation. The site of interaction between PTP1B and the insulin receptor was studied using phosphopeptides modeled after the receptor's kinase domain, the NPXY domain, and the COOH-terminal. Each phosphopeptide inhibited the PTP1B-GST:insulin receptor interaction. Study of mutant insulin receptors demonstrated that activation of the kinase domain is necessary for the PTP1B:insulin receptor interaction, but receptors with deletion of the NPXY domain or of the COOH-terminal can still bind to the PTP1B-GST. We conclude that PTP1B can associate directly with the activated insulin receptor at multiple different phosphotyrosine sites and that dephosphorylation by PTP1B may play a significant role in insulin receptor signal transduction.
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PMID:Protein tyrosine phosphatase 1B interacts with the activated insulin receptor. 882 75

Saccharomyces cerevisiae mutants that were unable to utilize extracellular ethanolamine for phosphatidylethanolamine synthesis were isolated. Two of them carried recessive chromosomal mutations in a same gene and were defective in CTP:phosphoethanolamine cytidylyltransferase (ECT) activity in vitro (Ect-). In an Ect- mutant that also carried the cho1 mutation, phosphatidylethanolamine accounted for less than 2% of total phospholipids, suggesting the importance of ECT in phosphatidylethanolamine synthesis. By screening a genomic library on a low copy number vector, three complementary clones of different size were isolated. A 2.8-kb common DNA region carried an open reading frame (ORF) of 969 bp in length, of which a truncated from failed to complement the Ect- mutation. This ORF was identical to the previously isolated MUQ1 gene of unknown function. Its deduced amino acid sequence had significant similarity to CTP: phosphocholine cytidylyl-transferases of yeast and rat. The entire ORF, when combined with the glutathione S-transferase gene and expressed in Escherichia coli, exhibited ECT activity. These results indicate that the cloned gene encodes a catalytic subunit of ECT of S. cerevisiae.
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PMID:Isolation and characterization of ECT1 gene encoding CTP: phosphoethanolamine cytidylyltransferase of Saccharomyces cerevisiae. 898 74

Components of cellular stress responses can be identified by correlating changes in stress tolerance with gain or loss of function of defined genes. Previous work has shown that yeast cells deficient in Ppz1 protein phosphatase or overexpressing Hal3p, a novel regulatory protein of unknown function, exhibit increased resistance to sodium and lithium, whereas cells lacking Hal3p display increased sensitivity. These effects are largely a result of changes in expression of ENA1, encoding the major cation extrusion pump of yeast cells. Disruption or overexpression of HAL3 (also known as SIS2) has no effect on salt tolerance in the absence of PPZ1, suggesting that Hal3p might function upstream of Ppz1p in a novel signal transduction pathway. Hal3p is recovered from crude yeast homogenates by using immobilized, bacterially expressed Ppz1p fused to glutathione S-transferase, and it also copurifies with affinity-purified glutathione S-transferase-Ppz1p from yeast extracts. In both cases, the interaction is stronger when only the carboxyl-terminal catalytic phosphatase domain of Ppz1p is expressed. In vitro experiments reveal that the protein phosphatase activity of Ppz1p is inhibited by Hal3p. Overexpression of Hal3p suppresses the reduced growth rate because of the overexpression of Ppz1p and aggravates the lytic phenotype of a slt2/mpk1 mitogen-activated protein kinase mutant (thus mimicking the deletion of PPZ1). Therefore, Hal3p might modulate diverse physiological functions of the Ppz1 phosphatase, such as salt stress tolerance and cell cycle progression, by acting as a inhibitory subunit.
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PMID:The yeast halotolerance determinant Hal3p is an inhibitory subunit of the Ppz1p Ser/Thr protein phosphatase. 963 53

The deduced product of the Bacillus subtilis ytvP gene is similar to that of ORF13, a gene of unknown function in the Lactococcus lactis histidine biosynthesis operon. A B. subtilis ytvP mutant was auxotrophic for histidine. The only enzyme of the histidine biosynthesis pathway that remained uncharacterized in B. subtilis was histidinol phosphate phosphatase (HolPase), catalyzing the penultimate step of this pathway. HolPase activity could not be detected in crude extracts of the ytvP mutant, while purified glutathione S-transferase-YtvP fusion protein exhibited strong HolPase activity. These observations demonstrated that HolPase is encoded by ytvP in B. subtilis and led us to rename this gene hisJ. Together with the HolPase of Saccharomyces cerevisiae and the presumed HolPases of L. lactis and Schizosaccharomyces pombe, HisJ constitutes a family of related enzymes that are not homologous to the HolPases of Escherichia coli, Salmonella typhimurium, and Haemophilus influenzae.
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PMID:Histidinol phosphate phosphatase, catalyzing the penultimate step of the histidine biosynthesis pathway, is encoded by ytvP (hisJ) in Bacillus subtilis. 1032 33

Cdc42 is a member of the Rho GTPase family that regulates multiple cellular activities, including actin polymerization, kinase-signaling activation, and cell polarization. MSE55 is a nonkinase CRIB (Cdc42/Rac interactive-binding) domain-containing molecule of unknown function. Using glutathione S-transferase-capture experiments, we show that MSE55 binds to Cdc42 in a GTP-dependent manner. MSE55 binding to Cdc42 required an intact CRIB domain, because a MSE55 CRIB domain mutant no longer interacted with Cdc42. To study the function of MSE55 we transfected either wild-type MSE55 or a MSE55 CRIB mutant into mammalian cells. In Cos-7 cells, wild-type MSE55 localized at membrane ruffles and increased membrane actin polymerization, whereas expression of the MSE55 CRIB mutant showed fewer membrane ruffles. In contrast to these results, MSE55 induced the formation of long, actin-based protrusions in NIH 3T3 cells as detected by immunofluorescence and live-cell video microscopy. MSE55-induced protrusion formation was blocked by expression of dominant-negative N17Cdc42, but not by expression of dominant-negative N17Rac. These findings indicate that MSE55 is a Cdc42 effector protein that mediates actin cytoskeleton reorganization at the plasma membrane.
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PMID:MSE55, a Cdc42 effector protein, induces long cellular extensions in fibroblasts. 1043 Aug 99

Neuronal Cdc2-like kinase (Nclk) is involved in the regulation of neuronal differentiation and neuro-cytoskeleton dynamics. The active kinase consists of a catalytic subunit, Cdk5, and a 25 kDa activator protein (p25nck5a) derived from a 35 kDa neuronal-specific protein (p35nck5a). As an extension of our previous study (Qi, Z., Tang, D., Zhu, X., Fujita, D.J., Wang, J.H., 1998. Association of neurofilament proteins with neuronal Cdk5 activator. J. Biol. Chem. 270, 2329-2335), which showed that neurofilament is one of the p35nck5a-associated proteins, we now report the isolation of three other novel p35nck5a-associated proteins using the yeast two-hybrid screen. The full-length forms of these three novel proteins, designated C42, C48 and C53, have a molecular mass of 66, 24, and 57 kDa, respectively. Northern analysis indicates that these novel proteins are widely expressed in human tissues, including the heart, brain, skeletal muscle, placenta, lung, liver, kidney and pancreas. The bacterially expressed glutathione S-transferase (GST)-fusion forms of these three proteins were able to co-precipitate p35nck5a complexed with Cdk5 from insect cell lysate. Among these three proteins, only C48 and C53 can be phosphorylated by Nclk, suggesting that they may be the substrates of Nclk. Sequence homology searches have suggested that the C48 protein is marginally related to restin protein, whereas the C42 protein has homologues of unknown function in Caenorhabditis elegans and Arabidopsis thaliana.
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PMID:Cloning of three novel neuronal Cdk5 activator binding proteins. 1072 22

Recent purification and cDNA cloning of the endoplasmic reticulum processing enzyme glucosidase II have revealed that it is composed of two soluble proteins: a catalytic alpha-subunit and a beta-subunit of unknown function, both of which are highly conserved in mammals. Since the beta-subunit, which contains a C-terminal His-Asp-Glu-Leu (HDEL) motif, may function to link the catalytic subunit to the KDEL receptor as a retrieval mechanism, we sought to map the regions of the mouse beta-subunit protein responsible for mediating the association with the alpha-subunit. By screening a panel of recombinant beta-subunit glutathione S-transferase fusion proteins for the ability to precipitate glucosidase II activity, we have identified two non-overlapping interaction domains (ID1 and ID2) within the beta-subunit. ID1 encompasses 118 amino acids at the N-terminus of the mature polypeptide, spanning the cysteine-rich element in this region. ID2, located near the C-terminus, is contained within amino acids 273-400, a region occupied in part by a stretch of acidic residues. Variable usage of 7 alternatively spliced amino acids within ID2 was found not to influence the association of the two sub-units. We theorize that the catalytic subunit of glucosidase II binds synergistically to ID1 and ID2, explaining the high associative stability of the enzyme complex.
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PMID:Two distinct domains of the beta-subunit of glucosidase II interact with the catalytic alpha-subunit. 1076 37

At present, only a little is known about the transcriptional regulation in chondrocytes submitted to various physicomechanical factors known to exist in articular cartilage. Recently, we have investigated the effects of hydrostatic pressure on transcriptional control in chondrocytes using human chondrosarcoma and immortalized chondrocyte cell lines for the experiments. Hydrostatic pressure was applied on the cells in a special computer-controlled, water-filled pressure chamber, where cyclic and static pressures up to 32 MPa can be created. Differential display RT-PCR and probing of cDNA arrays are the methods we have used to study differential gene expression due to hydrostatic pressure. By differential display RT-PCR experiments, we have observed several differentially expressed cDNA bands under continuous 30 MPa hydrostatic pressure, while 30 MPa cyclic pressure at 1 Hz produced much fewer changes. In the first phase of our studies, we have focused on the effects of 30 MPa hydrostatic pressure because it causes a unique hsp70-mediated stress response in immortalized chondrocytes. Differential display RT-PCR screening provided us with several clones that derive from low-abundance mRNAs, such as death-associated protein 3 (DAP3), a nucleotide-binding protein which increases due to interferon-gamma induced cell death; PTZ-17 (or p311), a seizure-related protein; H-NUC, a nuclear DNA binding protein; and one new gene of unknown function. In Northern blots, an induction was confirmed for the new gene, DAP3 and PTZ-17 were down-regulated in some but not in all parallel experiments; however, basal level of H-NUC mRNA was too low to be detected in Northern blots. We then chose to widen our screening to a number of known genes arrayed as cDNA blots. Under 30 MPa continuous hydrostatic pressure, four different time points were chosen (0, 3, 6 and 24 h) for the experiments. The screening of 588 cDNAs showed 15 up-regulated and 6 down-regulated genes. Consistently with our previous results hsp70 was highly induced, as well as hsp40, a chaperone protein functioning together with hsp70. Gadd45 and to a lesser extent Gadd153 (stress genes induced by, e.g., ionizing radiation and ischaemia) were up-regulated, as well as p21waf1,cip1, a protein participating in cell cycle regulation that can interact with Gadd45. Northern blots confirmed Gadd45 induction. Down-regulated transcripts included, e.g., DAD-1, glutathione S-transferase pI, DNA-binding inhibitor ID-1H, and cytoplasmic dynein light chain.
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PMID:Transcriptional activation in chondrocytes submitted to hydrostatic pressure. 1091 81


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