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 appearance of differentiated hepatocytes in the adult rat pancreas as well as pancreatic-type tissue in the adult rat liver can be experimentally induced (Reddy et al.: J. Cell Biol., 98:2082-2090, 1984; Rao et al., J. Histochem. Cytochem., 34:197-201, 1986). These observations suggest a lineage relationship between cell compartments present in rat liver and pancreas. The present data demonstrate that epithelial cell lines with almost identical phenotypes can be established from adult rat liver and pancreas. The established cell lines showed similar morphologies as established by light- and electron-microscopic studies. The cell lines showed a unique expression pattern of intermediate filament proteins. Vimentin, actin, and beta-tubulin were present in all cell lines. In addition, simple epithelial type II cytokeratins 7 and 8 were found to be coexpressed with the type I cytokeratin 14 in several of the cell lines. Neither the type I cytokeratins 18 and 19, which are the normal partners for cytokeratins 8 and 7 in filament formation, nor the type II cytokeratin 5 could be detected despite the fact that filaments were formed by both cytokeratins 8 and 14. This suggests that cytokeratin 14 acts as an indiscriminate type I cytokeratin in filament formation in the established cell lines. The cell lines expressed the same sets of LDH and aldolase isoenzymes and identical sets of glutathione transferase subunits. In addition, the epithelial cell lines from liver and pancreas were equally sensitive to the growth-inhibitory effects of TGF-beta 1. No expression of tissue- or cell-specific proteins such as alpha-fetoprotein, albumin, amylase, elastase, or gamma-glutamyl transpeptidase were detected. The almost identical phenotypes of the hepatic and pancreatic cell lines suggest that they may be derived from a common primitive epithelial cell type present in both rat liver and pancreas. In contrast to parenchymal cells, these cells have an extended capacity for proliferation in vitro and may represent a progeny from a "precursor" or "stem" cell compartment in vivo.
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PMID:Evidence for a common cell of origin for primitive epithelial cells isolated from rat liver and pancreas. 171 Feb 29

Ethacrynic acid (EA) is a plant phenolic acid that is both an inhibitor and an inducer of glutathione S-transferase (GST) activity. To determine contributory factors in the increased GST activity caused by EA treatment, human colon carcinoma HT29 cells were compared with a cloned EA-resistant population (HT6-8) maintained in medium containing 72 microM EA. Several factors are involved in the increased expression of GST pi in HT6-8. For example, nuclear run-on experiments showed an approximately 2-fold increase in the rate of transcription of GST pi. In addition, the half-life of GST pi transcript was increased from 4.1 (wild type, HT29, HT4-1) to 8.4 hr. The half-life of GST pi protein was 1-2 hr in HT4-1 cells versus 8-9 hr in HT6-8 cells. When either human ovarian carcinoma cells (SKOV3) or human prostatic carcinoma cells (DU145) were treated with EA, the half-life of the GST pi transcript was also increased. The transcript half-lives of another thiol-metabolism enzyme, gamma-glutamylcysteine synthetase (gamma-GCS), and a phase II detoxification enzyme, dihydrodiol dehydrogenase (DDH), were also increased in HT6-8, SKOV3 and DU145 cells treated with EA. However, the half-lives of transcripts from "housekeeping genes," such as glyceraldehyde 3-phosphate dehydrogenase (G3PDH), beta-actin and beta-tubulin, were not changed in these cell lines following EA. Apparently, a number of coordinated factors are involved in EA-enhanced expression of GST pi and other detoxification enzymes.
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PMID:Influence of ethacrynic acid on glutathione S-transferase pi transcript and protein half-lives in human colon cancer cells. 748 39

The Nm23 protein is a nucleoside diphosphate kinase (NDPK) and is thought to play a critical role in metastatic behavior. It has been reported that a NDPK activity is present in microtubules assembled in vitro. Since microtubule assembly is determinant in cell growth and differentiation, we investigated whether Nm23-M1 forms molecular complexes with beta-tubulin in murine cells either actively proliferating or differentiating. For this purpose a polyclonal antibody against the GST-Nm23-M1 fusion protein was generated and employed to detect Nm23-M1/beta-tubulin complexes in murine tumor cells derived from the Lewis lung carcinoma (3LL) and in undifferentiated and differentiated myogenic cells (C2C12). Immunoblotting and immunoprecipitation experiments performed using the anti-fusion protein antibody demonstrated that the Nm23-M1 protein is detectable in in vitro tumor cell lines and in in vivo primary tumors but not in spontaneous lung metastases. These data are in good agreement with data previously reported. Immunoprecipitation experiments demonstrated that the Nm23-M1 protein forms complexes with beta-tubulin in in vitro tumor cell lines, but not in primary tumors. Furthermore, the Nm23-M1 protein forms complexes with beta-tubulin in myogenic cells prior to and after differentiation. Interestingly, however, the level of the Nm23-M1/beta-tubulin complexes is remarkably increased in differentiated myotubes. In conclusion, the results indicate that the Nm23-M1 protein forms molecular complexes with beta-tubulin and that the number of complexes increases during the differentiation process of murine cells.
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PMID:The association of the Nm23-M1 protein and beta-tubulin correlates with cell differentiation. 769 25

Natural resistance to infection with intracellular parasites, such as Leishmania, Salmonella, and Mycobacterium, is controlled in mice by the expression of a single dominant gene locus designated Lsh/Ity/Bcg. Natural resistance-associated macrophage protein gene 1 (NRAMP1) was isolated as a candidate gene. NRAMP1 encodes an M(r) 60000 polypeptide with 10-12 potential transmembrane domains and an evolutionary conserved consensus transport motif. The present study shows that the human NRAMP1 molecule is expressed in all cell lineages of macrophage/monocyte and B- and T-lymphocytes. Immunohistochemical analysis using antihuman NRAMP1 antibody provides the direct evidence that the NRAMP1 molecule is located and distributed on the plasma membrane. An NRAMP1-glutathione S-transferase (GST) fusion protein was used to affinity-purify a protein, bound to the NH2-terminal cytoplasmic domain of NRAMP1. It was found that the NRAMP1 molecule was associated with alpha- and beta-tubulin of microtubules. These results suggest that NRAMP1 may function as a molecule, possessing the abilities of membrane-anchoring and microtubule-binding, for the microtubule-mediated transport of vesicles and be a new class of microtubule-associated proteins.
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PMID:Location of NRAMP1 molecule on the plasma membrane and its association with microtubules. 912 60

The mixed lineage kinase 2 (MLK2) protein contains several structurally distinct domains including an src homology (SH) 3 domain, a kinase catalytic domain, two leucine zippers, a basic motif and a cdc42/rac interactive binding motif. These domains have been recognized mainly for their involvement in protein-protein interactions in signal transduction networks. The SH3 domain in particular has been implicated in control of signaling events. To identify proteins that interact with MLK2, the N-terminal 100 amino acids, including the SH3 domain, were expressed as a glutathione S-transferase (GST) fusion protein. This fusion protein (MLK2N) was used as an affinity ligand to isolate binding proteins from lysates of 35S-radiolabeled MDA-MB231 breast carcinoma cells. When the radiolabeled binding proteins were subjected to 2-DE, proteins of Mr 55,000, 31,500 and 34,000 bound consistently to the MLK2N domain fusion protein, but not to the GST control. Two of the binding proteins were isolated from whole cell lysates by preparative 2-DE and subjected to in-gel digestion and capillary or microbore reverse-phase high performance liquid chromatography (RP-HPLC). Resultant peptides were analyzed by peptide mass fingerprinting, N-terminal Edman degradation or tandem mass spectrometry. The 55,000 protein was identified as the cytoskeletal protein, beta-tubulin, and this was verified by immunoblotting of proteins in the MLK2N binding fraction with anti-tubulin antibodies. The 31,500 protein has been identified as prohibitin, a protein that has been implicated in both signal transduction and cell cycle arrest.
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PMID:Two-dimensional electrophoretic analysis of mixed lineage kinase 2 N-terminal domain binding proteins. 962 20

Overexpression of 'tissue' transglutaminase (tTG) in the human neuroblastoma cells increases spontaneous apoptosis and renders these cells highly susceptible to death induced by various stimuli. We used immunoprecipitation to identify cellular proteins that interact specifically with tTG in SK-N-BE(2) -derived stable transfectants. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis showed that tTG binding proteins have molecular masses of 110, 50, 22, 14, and 12 kDa. Microsequencing and computer search analyses allowed us to identify these polypeptides as the beta-tubulin (50 kDa), the histone H2B (14 kDa), and two GST P1-1-truncated forms (22 and 12 kDa). The specificity of the interaction between tTG and these proteins was confirmed by competing tTG binding with purified enzyme and by detecting tTG in immunoprecipitates obtained using beta-tubulin or GST P1-1 mAb's. Here we demonstrate that the GST P1-1 acts as an efficient acyl donor as well as acceptor tTG substrate both in cells and in vitro. The tTG-catalyzed polymerization of GST P1-1 leads to its functional inactivation and is competitively inhibited by GSH. By contrast, the tTG-beta-tubulin interaction does not result in the cross-linking of this cytoskeletal protein, which suggests that microtubules act as the anchorage site for tTG and GST P1-1 interaction.
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PMID:Identification of 'tissue' transglutaminase binding proteins in neural cells committed to apoptosis. 997 24

The translationally controlled protein P23 was discovered by the early induction of its rate of synthesis after mitogenic stimulation of mouse fibroblasts. P23 is expressed in almost all mammalian tissues and it is highly conserved between animals, plants and yeast. Based on its amino acid sequence, P23 cannot be attributed to any known protein family, and its cellular function remains to be elucidated. Here, we present evidence that P23 has properties of a tubulin binding protein that associates with microtubules in a cell cycle-dependent manner. (1) P23 is a cytoplasmic protein that occurs in complexes of 100-150 kDa, and part of P23 can be immunoprecipitated from HeLa cell extracts with anti-tubulin antibodies. (2) In immunolocalisation experiments we find P23 associated with microtubules during G1, S, G2 and early M phase of the cell cycle. At metaphase, P23 is also bound to the mitotic spindle, and it is detached from the spindle during metaphase-anaphase transition. (3) A GST-P23 fusion protein interacts with alpha- and beta-tubulin, and recombinant P23 binds to taxol-stabilised microtubules in vitro. The tubulin binding domain of P23 was identified by mutational analysis; it shows similarity to part of the tubulin binding domain of the microtubule-associated protein MAP-1B. (4) Overexpression of P23 results in cell growth retardation and in alterations of cell morphology. Moreover, elevation of P23 levels leads to microtubule rearrangements and to an increase in microtubule mass and stability.
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PMID:The growth-related, translationally controlled protein P23 has properties of a tubulin binding protein and associates transiently with microtubules during the cell cycle. 1008 60

The interaction between elongation factor 1alpha (EF-1alpha) and alpha/beta-tubulins has been analyzed in vivo and in vitro. An association of both alpha- and beta-tubulins with EF-1alpha in the lysate of Tetrahymena pyriformis was detected by co-immunoprecipitation analysis. In contrast, in vitro biomolecular interaction analysis with glutathione S-transferase (GST) fusion proteins revealed that GST-beta-tubulin, but not GST-alpha-tubulin, can bind to GST-EF-1alpha. Two beta-tubulin binding sites have been identified to reside in the domains I and III of EF-1alpha. In addition, beta-tubulin itself seems to have two distinct interaction sites for each of the domains. Since domain II of EF-1alpha did not interact with beta-tubulin, we have re-evaluated the phylogenetic status of ciliates using EF-1alpha sequences devoid of domain II. The phylogenetic tree thus obtained was significantly different from that inferred from the whole sequence of EF-1alpha, suggesting the presence of functional constraints on the molecular evolution of EF-1alpha.
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PMID:Biochemical analysis of the interaction between elongation factor 1alpha and alpha/beta-tubulins from a ciliate, Tetrahymena pyriformis. 1040 69

There are five regulatory subunit isoforms of phosphoinositide 3-kinase (PI 3-kinase), which are classified into three groups: proteins of 85 kDa (p85alpha and p85beta), 55 kDa (p55alpha and p55gamma) and 50 kDa (p50alpha). Structural differences between the three groups reside in the N-terminus. To elucidate the unique functional role of the 55 kDa regulatory subunits, GST (glutathione S-transferase) fusion proteins containing a unique N-terminal portion consisting of a 34-amino-acid sequence of p55alpha or p55gamma (GST-p55alpha/gammaN(1-34)) were used as affinity matrices to screen rat brain cell extracts for proteins to which this portion binds specifically. A protein that bound was identified as beta-tubulin by protein sequencing. In addition, not only the beta isoform of tubulin, but also the alpha and gamma isoforms, were detected in the protein absorbed from cell lysates with GST-p55gammaN(1-34) and GST-p55alphaN(1-34) by immunoblotting. Indeed, the only regulatory subunit present in the purified microtubule assembly from rat brain was the 55 kDa isoform; neither 85 kDa nor 50 kDa subunits were detected. These results indicate endogenous binding of 55 kDa regulatory subunits of PI 3-kinase to tubulin in the brain. Finally, we measured tubulin-associated PI 3-kinase activity in CHO/IR cells overexpressing each of the five regulatory subunit isoforms. Only in cells expressing p55alpha or p55gamma was there a significant elevation of tubulin-associated PI 3-kinase activity in response to insulin. These results suggest that the p55alpha and p55gamma regulatory subunits have important roles in regulating PI 3-kinase activity, particularly for microtubules at the cell periphery.
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PMID:The N-terminal 34 residues of the 55 kDa regulatory subunits of phosphoinositide 3-kinase interact with tubulin. 1067 70

The microtubule disrupting agent 2-fluoro-1-methoxy-4-pentafluorophenylsu lfonamidobenzene (T138067) binds covalently and selectively to beta-tubulin and has been shown to evade drug-efflux pumps that confer multidrug resistance to other antimitotic drugs that are used in cancer chemotherapy (Shan et al., 1999). In addition to these resistance mechanisms, eukaryotic cells have developed other protection mechanisms that involve enzymes that modify electrophilic xenobiotics. To determine whether T138067 is a substrate for such enzymatic detoxification pathways, a metabolism study was initiated. GSH conjugation was shown to play a major role in T138067 metabolism. T138067-GSH conjugates were isolated from the culture media of T138067-treated cells and the bile of mice treated i.v. with T138067. The major T138067-GSH degradation products were also isolated from these sources. 19F NMR studies of the metabolites showed that metabolic conversions occurred through substitution of the para fluorine atom in the pentafluorophenyl ring of T138067. The T138067-GSH conjugate was also isolated from T138067 incubation buffer that had been exposed to mouse, rat, dog, or human liver slices, suggesting that this mechanism is not species-specific. All three human glutathione S-transferases (alpha, mu, and pi), which are expressed in a wide variety of tissues including human tumors, were shown to metabolize T138067 effectively in vitro. The combined data show that T138067 is being metabolized, in vitro and in vivo, predominantly via a glutathione S-transferase-mediated metabolic pathway.
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PMID:Glutathione S-transferase metabolism of the antineoplastic pentafluorophenylsulfonamide in tissue culture and mice. 1090 6


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