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

The Philadelphia chromosome translocation generates a chimeric oncogene, BCR/ABL, which causes chronic myelogenous leukemia (CML). In primary neutrophils from patients with CML, the major novel tyrosine-phosphorylated protein is CRKL, an SH2-SH3-SH3 linker protein which has an overall homology of 60% to CRK, the human homologue of the v-crk oncogene product. Anti-CRKL immunoprecipitates from CML cells, but not normal cells, were found to contain p210BCR/ABL and c-ABL. Several other phosphoproteins were also detected in anti-CRKL immunoprecipitates, one of which has been identified as paxillin, a 68-kDa focal adhesion protein which we have previously shown to be phosphorylated by p210BCR/ABL. Using GST-CRKL fusion proteins, the SH3 domains of CRKL were found to bind c-ABL and p210BCR/ABL, while the SH2 domain of CRKL bound to paxillin, suggesting that CRKL could physically link p210BCR/ABL to paxillin. Paxillin contains three tyrosines in Tyr-X-X-Pro (Y-X-X-P) motifs consistent with amino acid sequences predicted to be optimal for binding to the CRKL-SH2 domain (at positions Tyr-31, Tyr-118, and Tyr-181). Each of these tyrosine residues was mutated to a phenylalanine residue, and in vitro binding assays indicated that paxillin tyrosines at positions 31 and 118, but not 181, are likely to be involved in CRKL-SH2 binding. These results suggest that the p210BCR/ABL oncogene may be physically linked to the focal adhesion-associated protein paxillin in hematopoietic cells by CRKL. This interaction could contribute to the known adhesive defects of CML cells.
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PMID:CRKL links p210BCR/ABL with paxillin in chronic myelogenous leukemia cells. 749 40

The c-ABL tyrosine kinase is activated following either the loss or mutation of its Src homology domain 3 (SH3), resulting in both increased autophosphorylation and phosphorylation of cellular substrates and cellular transformation. This suggests that the SH3 domain negatively regulates c-ABL kinase activity. For several reasons this regulation is thought to involve a cellular protein that binds to the SH3 domain. Hyperexpression of c-ABL results in an activation of its kinase, the kinase activity of purified c-ABL protein in the absence of cellular proteins is independent of either the presence or absence of a SH3 domain, and point mutations and deletions within the SH3 domain are sufficient to activate c-ABL transforming ability. To identify proteins that interact with the c-ABL SH3 domain, we screened a cDNA library by the yeast two-hybrid system, using the c-ABL SH3SH2 domains as bait. We identified a novel protein, AAP1 (ABL-associated protein 1), that associates with these c-ABL domains and fails to bind to the SH3 domain in the activated oncoprotein BCRABL. Kinase experiments demonstrated that in the presence of AAP1, the ability of c-ABL to phosphorylate either glutathione S-transferase-CRK or enolase was inhibited. In contrast, AAP1 had little effect on the phosphorylation of glutathione S-transferase-CRK by the activated ABL oncoproteins v-ABL and BCRABL. We conclude that AAP1 inhibits c-ABL tyrosine kinase activity but has little effect on the tyrosine kinase activities of oncogenic BCRABL or v-ABL protein and propose that AAP1 functions as a trans regulator of c-ABL kinase. Our data also indicate that loss of susceptibility to AAP1 regulation correlates with oncogenicity of the activated forms of c-ABL.
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PMID:c-ABL tyrosine kinase activity is regulated by association with a novel SH3-domain-binding protein. 894 60

BCR-ABL is a chimeric oncoprotein that exhibits deregulated tyrosine kinase activity and is implicated in the pathogenesis of Philadelphia chromosome (Ph1)-positive leukemia. We have previously shown SH2-containing phosphotyrosine phosphatase SHP-2 forms stable complexes with BCR-ABL and Grb2 in BCR-ABL-transformed cells (Tauchi, T., Feng, G. S., Shen, R., Song, H. Y., Donner, D., Pawson, T., and Broxmeyer, H. E. (1994) J. Biol. Chem. 269, 15381-15387). To elucidate the structural requirement of BCR-ABL for the interactions with SH2-containing signaling molecules, we examined a series of BCR-ABL mutants which include the Grb2 binding site-deleted BCR-ABL (1-63 BCR/ABL), the tetramerization domain-deleted BCR-ABL (64-509 BCR/ABL), and the SH2 domain-deleted BCR-ABL (BCR/ABL deltaSH2). These BCR-ABL mutants were previously shown to reduce the transforming activity in fibroblasts. We found that the tetramerization domain-deleted BCR-ABL did not induce the tyrosine phosphorylation of SHP-2 and the interactions of BCR-ABL, SHP-2, and Grb2. In vitro kinase assays have also shown that the tetramerization domain-deleted BCR-ABL mutant did not phosphorylate GST-SHP-2 in vitro. SHP-2 was co-immunoprecipitated with phosphatidylinositol 3-kinase in BCR/ABL p210-transformed cells; however, this interaction was not observed in the tetramerization domain-deleted BCR-ABL mutant. Therefore the tetramerization domain of BCR-ABL is essential for interactions of these downstream molecules.
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PMID:A coiled-coil tetramerization domain of BCR-ABL is essential for the interactions of SH2-containing signal transduction molecules. 899 49

BCR-ABL is a chimeric oncoprotein that exhibits deregulated tyrosine kinase activity and is implicated in the pathogenesis of Philadelphia chromosome (ph1)-positive leukemia. We have previously shown SH2-containing phosphotyrosine phosphatase SHP-2 forms stable complexes with BCR-ABL and Grb2 in BCR-ABL transformed cells (T., Tauchi, et al. J. Biol. Chem. 269, 15381, 1994). To elucidate the structural requirement of BCR-ABL for the interactions with SH2-containing signaling molecules, we examined a series of BCR-ABL mutants which include the Grb2 binding site deleted BCR-ABL (1-63 BCR/ABL), the tetramerization domain deleted BCR-ABL (64-509 BCR/ABL), and the SH2 domain deleted BCR-ABL (BCR/ABL delta SH2). These BCR-ABL mutants were previously shown to reduce the transforming activity in fibroblasts. We found that the tetramerization domain deleted BCR-ABL did not induce the tyrosine phosphorylation of SHP-2 and the interactions of BCR-ABL, SHP-2, and Grb2. In vitro kinase assays have also shown the tetramerization domain deleted BCR-ABL mutant did not phosphorylate GST-SHP-2 in vitro. SHP-2 was co-immunoprecipitated with P13Kinase in BCR/ABL p210 transformed cells, however this interaction was not observed in the tetramerization domain deleted BCR-ABL mutant. Therefore the tetramerization domain of BCR-ABL is essential for interactions of these downstream molecules.
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PMID:A coiled-coil tetramerization domain of BCR-ABL is essential for the interactions of SH2-containing signal transduction molecules. 918 66

The BCR gene is involved in the formation of the BCR-ABL oncogene responsible for the pathogenesis of Philadelphia chromosome-positive human leukemias. We have previously shown that P210 BCR-ABL binds to the xeroderma pigmentosum group B protein (XPB) through the portion of BCR that is homologous to the catalytic domain of GDP-GTP exchangers such as yeast CDC24 and Dbl. In the baculovirus overexpression system which facilitates binding of coexpressed proteins, we now show that XPB binds to the intact BCR protein efficiently but not to CDC24 or Dbl, suggesting specificity of this interaction. The binding of endogenous BCR and XPB proteins was also detected in Hela cells, and this was inhibited by a blocking peptide. Full-length (1-782) XPB and its truncated form (203-782), which does not contain the nuclear localization signal, were tagged with glutathione S-transferase (GST) and were expressed in Rat1 fibroblasts. GST-XPB(203-782) was localized predominantly in the cytoplasm and bound to BCR but not to p62, one of the other components in TFIIH. GST-XPB(1-782) was largely in the nucleus and bound to p62 and BCR. Although the biological significance of the binding remains to be uncovered, BCR binds to the XPB/p62 complex.
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PMID:BCR binds to the xeroderma pigmentosum group B protein. 1040 66

Our laboratory has been involved in the study of glutathione-sulfhydryl-transferase-pi (GST-pi) for several years. We have recently observed that during haematopoiesis in BMSC liquid cultures from CML patients who were candidates for transplant GST-pi was expressed in presumably malignant cells during different stages of cellular maturation. To confirm this finding, in the present work we are detecting GST-pi expression by immunofluorescence in BCR-ABL+ and BCR-ABL- cells done by FISH of PB from 30 CML patients during different clinical status: treatment (T), hematological relapse (R), blastic crisis (BC) or post-allotrasplant (PT). As well as in PB from 30 Blood-Bank donors. The results were %BCR-ABL+ GST-pi+ cells: T = 1-67, R = 33-69, BC = 90-100 and PT = 1-2; %BCR-ABL- GST-pi+ cells: T = 2-31, R = 5-18, BC = 0-10 and PT = 2-5; %BCR-ABL- GST-pi- cells: T = 2-97, R = 13-62, BC = 0 and PT = 93-96; %BCR-ABL+ GST-pi- cells: T = 0, R = 0, BC = 0 and PT = 0. GST-pi was not expressed in donor cells. The results obtained confirm our previous observations and suggest that GST-pi expression might be used for the evaluation of the minimal residual disease in CML patients.
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PMID:GST-pi expression in BCR-ABL+ and BCR-ABL- cells from CML patients. 1095 10

We have previously reported that the Jak2 tyrosine kinase but not Jak1 is tyrosine phosphorylated in the absence of IL-3 in Bcr-Abl positive M3.16 cells, which are rendered IL-3 independent by BCR-ABL gene expression. We have explored the involvement of Jak2 tyrosine phosphorylation in Bcr-Abl oncogenic effects. Our results indicate that Jak2 became tyrosine-phosphorylated in a number of cell lines expressing Bcr-Abl, when maintained in medium lacking IL-3, whereas Bcr-Abl negative cells lacked Jak2 tyrosine phosphorylation. Jak2 was poorly tyrosine-phosphorylated in cells expressing the SH2 deletion mutant of Bcr-Abl compared to either wild-type Bcr-Abl or its SH3 deletion mutant. Moreover, tyrosine phosphorylation of Jak2 by Bcr-Abl was inhibited by the Abl tyrosine kinase inhibitor, STI 571, in a dose-dependent manner. This inhibition of Bcr-Abl kinase by the drug did not interfere with the ability of Jak2 and Bcr-Abl to form a complex. Studies with deletion mutants of Bcr-Abl indicated that the C-terminal domain of Abl within Bcr-Abl was involved in complex formation with Jak2. Similarly, GST-Abl pull-down assays confirmed the strong binding to Jak2 by the C-terminus of Abl. Jak2 peptide substrate studies indicated that the Bcr-Abl and Abl tyrosine kinases specifically phosphorylated Y1007 of Jak2 but only poorly phosphorylated Y1008. Phosphorylation of Y1007 of Jak2 is known to be critical for its tyrosine kinase activation. Tyrosine residue 1007 of Jak2 was phosphorylated in 32Dp210 cells as measured by Western blotting with a phosphotyrosine 1007 sequence-specific antibody. A kinase-inactive Jak2 mutant blocked the colony forming ability of K562 cells. Tumor formation of K562 cells in nude mice was similarly inhibited by this kinase-inactive Jak2 mutant. This inhibition was independent of Stat5 tyrosine phosphorylation. Furthermore, tyrosine-phosphorylated Jak2 was detected in blood cells from CML patients in blast crisis but not in a normal marrow sample. In summary, these findings provide strong evidence that the Jak2 tyrosine kinase is a critical factor in Bcr-Abl malignant transformation.
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PMID:Involvement of Jak2 tyrosine phosphorylation in Bcr-Abl transformation. 1159 27

Recent study has shown that nuclear glutathione S-transferase (GST) pi accumulates in cancer cells resistant to doxorubicin hydrochloride (DOX) and may function to prevent nuclear DNA damage caused by DOX (Goto et al., FASEB J., 15, 2702 - 2714 (2001)). It is not clear if the amount of nuclear GSTpi increases in response to other anti-cancer drugs and if so, what is the physiological significance of the nuclear transfer of GSTpi in the acquisition of drug-resistance in cancer cells. In the present study, we employed three cancer cell lines, HCT8 human colonic cancer cells, A549 human lung adenocarcinoma cells, and T98G human glioblastoma cells. We estimated the nuclear transfer of GSTpi induced by the anti-cancer drugs cisplatin (CDDP), irinotecan hydrochloride (CPT-11), etoposide (VP-16) and 5-fluorouracil (5-FU). It was found that: (1) Nuclear GSTpi accumulated in these cancer cells in response to CDDP, DOX, CPT-11, VP-16 and 5-FU. (2) An inhibitor of the nuclear transport of GSTpi, edible mushroom lectin (Agaricus bisporus lectin, ABL), increased the sensitivity of the cancer cells to DOX and CDDP, and partially to CPT-11. Treatment with ABL had no apparent effect on the cytotoxicity of VP-16 and 5-FU. These results suggest that inhibitors of the nuclear transfer of GSTpi have practical value in producing an increase of sensitivity to DOX, CDDP and CPT-11.
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PMID:Significance of nuclear glutathione S-transferase pi in resistance to anti-cancer drugs. 1235 59

Expression of BCR-ABL is the leading cause of chronic myelogenous leukemia. In chronic myelogenous leukemia cells, c-Abl expression is silenced by promoter methylation. In addition, the level of c-Abl needs to be tightly and constantly regulated due to its cytotoxicity and its rapid degradation after activation. Yet the regulation of c-Abl expression remains unclear. In an effort to gain better understanding of c-Abl function, we performed a glutathione S-transferase-Abl pull-down screen and identified TopBP1, a topoisomerase IIbeta-binding protein that contains Brca1 C-terminal motifs and has been implicated in DNA damage response. Their physical interaction was verified by in vitro and in vivo assays with TopBP1 found as a substrate of Abl proteins. TopBP1 could repress the expression of c-Abl at both mRNA and protein levels. Reporter assays indicate that TopBP1 directly repressed the promoter activity of c-Abl. Furthermore, TopBP1 repressed expression of c-Abl through a novel mechanism that involved histone deacetylation and DNA methylation. This transcriptional repression was inhibited by c-Abl in a kinase-dependent manner. The dual antagonistic interplay between c-Abl and TopBP1 may also provide a mechanism for fine-tuning of c-Abl levels.
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PMID:Identification of TopBP1 as a c-Abl-interacting protein and a repressor for c-Abl expression. 1596 88