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)

RRR-alpha-tocopherol succinate (vitamin E succinate, VES) is a potent, selective apoptotic agent for cancer cells but not normal cells. VES has been shown to inhibit the growth of a wide variety of tumor cells in cell culture and animal models. Studies addressing mechanisms of action of VES-induced apoptosis have identified transforming growth factor-beta, Fas/CD95-APO-1, and mitogen-activated protein kinase (MAPK) signaling pathway involvement. Here we show that MAPKs, the extracellular signal-regulated kinases (ERK), and the stress-activated protein kinases, c-Jun NH2-terminal kinases (JNK), but not p38, are critical mediators in VES-induced apoptosis of human breast cancer MDA-MB-435 cells. VES activates ERK1/2 and JNK both in level and duration of kinase activity. Expression of dominant negative mutants of ERK1, MAPK/ERK activator-1, or JNK1 but not p38 blocked phosphorylation of the substrate glutathione S-transferase-c-Jun and inhibited VES-induced apoptosis. Increased phosphorylation and transactivation activity of nuclear transcription factors c-Jun, ATF-2, and Elk-1 are observed after VES treatments; however, only c-Jun and ATF-2 appear to be involved in VES-induced apoptosis based on antisense blockage experiments. Collectively, these results imply a critical role for ERK1 and JNK1 but not p38 in VES-induced apoptosis of human MDA-MB-435 breast cancer cells.
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PMID:Activation of extracellular signal-regulated kinase and c-Jun-NH(2)-terminal kinase but not p38 mitogen-activated protein kinases is required for RRR-alpha-tocopheryl succinate-induced apoptosis of human breast cancer cells. 1152 56

Apoptosis-linked gene 2 (ALG-2) is a member of the family of Ca(2+)-binding proteins with penta-EF-hand and is essential for the execution of apoptosis by various signals including Fas activation. We studied the regulation of ALG-2 during Fas-mediated apoptosis in Jurkat cells. The 22-kDa ALG-2 protein is cleaved and becomes a 19-kDa protein after Fas activation. The appearance of 19-kDa ALG-2 protein increases for 4 h after treatment with 200 ng/ml of anti-Fas Ab treatment and gradually degrades afterward. Confocal microscopic analysis showed that ALG-2 translocated from the plasma membrane to the cytosol during Fas-mediated apoptosis. Therefore, we examined if ALG-2 interacts with Fas. The protein-protein interaction of ALG-2 with Fas was demonstrated using yeast two-hybrid assays as well as in vitro GST pull-down assay. Endogenous ALG-2 was immunoprecipitated with anti-Fas Ab in Jurkat cells without Fas activation. However, the endogenous ALG-2 was no longer immunoprecipitated with anti-Fas Ab 2 h after anti-Fas Ab treatment. This study, for the first time, presents a direct molecular connection of ALG-2 to apoptosis by its direct interaction with Fas, and enlists ALG-2 as a new member of posttranslationally modified proteins during Fas-mediated apoptotic process.
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PMID:Apoptosis-linked gene 2 binds to the death domain of Fas and dissociates from Fas during Fas-mediated apoptosis in Jurkat cells. 1160 59

p75(NTR), a nerve growth factor co-receptor that has been implicated in apoptosis of neurons, is structurally related to Fas and the receptors for tumor necrosis factor-alpha that display ligand independent assembly into trimers. Using embryonic day 17 fetal rat cortical neurons and p75(NTR)-expressing NIH-3T3 cells, we now show that p75(NTR) exists as a trimer as well as a monomer. Furthermore, we have reported and others have confirmed that amyloid beta binds p75(NTR), and that this binding leads to apoptotic cell death. We now report that amyloid beta binds to trimers of p75(NTR) as well as to p75(NTR) monomers but not to the p140(trkA), the nerve growth factor co-receptor that mediates neuronal survival. Furthermore, amyloid beta activates p75(NTR), strongly inducing the transcription of c-Jun mRNA and stimulating the stress-activated c-Jun NH(2)-terminal kinase, as measured by phosphorylation of its substrate (glutathione S-transferase-c-Jun-(1-79)). Our data suggest that p75(NTR) may be present as a preformed trimer that binds amyloid beta to induce receptor activation, and support the hypothesis that p75(NTR) activation by amyloid beta is causally related to Alzheimer's disease.
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PMID:Amyloid beta binds trimers as well as monomers of the 75-kDa neurotrophin receptor and activates receptor signaling. 1175 26

Activation of the tumor necrosis factor R1/Fas receptor results in the cleavage of cytosolic BID to truncated tBID. tBID translocates to the mitochondria to induce the oligomerization of BAX or BAK, resulting in the release of cytochrome c (Cyt c). Here we demonstrate that in tumor necrosis factor alpha-activated FL5.12 cells, tBID becomes part of a 45-kDa cross-linkable mitochondrial complex that does not include BAX or BAK. Using fluorescence resonance energy transfer analysis and co-immunoprecipitation, we demonstrate that tBID-tBID interactions occur in the mitochondria of living cells. Cross-linking experiments using a tBID-GST chimera indicated that tBID forms homotrimers in the mitochondrial membrane. To test the functional consequence of tBID oligomerization, we expressed a chimeric FKBP-tBID molecule. Enforced dimerization of FKBP-tBID by the bivalent ligand FK1012 resulted in Cyt c release, caspase activation, and apoptosis. Surprisingly, enforced dimerization of tBID did not result in the dimerization of either BAX or BAK. Moreover, a tBID BH3 mutant (G94E), which does not interact with or induce the dimerization of either BAX or BAK, formed the 45-kDa complex and induced both Cyt c release and apoptosis. Thus, tBID oligomerization may represent an alternative mechanism for inducing mitochondrial dysfunction and apoptosis.
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PMID:tBID Homooligomerizes in the mitochondrial membrane to induce apoptosis. 1180 84

We generated and characterized novel antibodies specific for a cleavage site of human caspase-8/FLICE and its substrate, FLICE-like inhibitory protein (FLIP). The synthetic peptides used as immunogens were CQGDNYQKGIPVETD (#791) and VSEGQLEDSSLLEVD (#1342), which corresponded to cleaved regions of N-terminal fragments of caspase-8 and FLIP generated by active caspase-8, respectively. Each antibody purified from rabbit antiserum reacted specifically with the immunogen but not with the peptide corresponding to the unproteolyzed form, as assessed by ELISA. In vitro cleavage of GST-FLIP by active caspase-8 generated an N-terminal fragment (GST-p43) and a C-terminal one (p12). Consistent with other in vivo data, the FLIP cleavage site follows the Asp residue, LEVD(376)GPAMKNVEF, identified on N-terminal sequencing of the p12 fragment. #1342-antibody (#1342-Ab) recognized the GST-p43 fragment but not the uncleaved protein, thus confirming its specificity. When the antibodies were used for immunoblotting, flow cytometry, and confocal laser microscopy, the proteolysis of caspase-8 and FLIP, and the subcellular localization of their digests could be monitored in apoptotic U937 cells. Interestingly, a significant increase in the percentage of cells exhibiting caspase-8 and FLIP cleavage was observed upon Fas stimulation in interferon-gamma-treated U937 cells, in which the susceptibility to Fas is extremely enhanced. In contrast, U937 cells treated with vitamin D(3) or all-trans retinoic acid showed Fas-resistance, and caspase-8 processing and FLIP cleavage were strongly inhibited. In conclusion, we established a system based on the cleavage site-directed antibodies to monitor the dynamics of caspase-8 processing and activation during apoptosis. Using this system, we found that Fas-susceptibility changes during U937 differentiation occur upstream of caspase-8 processing/activation.
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PMID:Monitoring of caspase-8/FLICE processing and activation upon Fas stimulation with novel antibodies directed against a cleavage site for caspase-8 and its substrate, FLICE-like inhibitory protein (FLIP). 1209 60

Mechanisms leading to morphological changes of the small intestine during coeliac disease (CD) are not yet completely recognized; however, two main processes have been suggested recently: remodeling of mucosa by matrix metalloproteinases, and mucosal atrophy by apoptosis. The aim of this study was analysis of the expression of proteins regulating apoptosis in the small intestine of children with active CD (ACD) and potential CD (PCD). Jejunal biopsies of 43 children with PCD and untreated ACD and 21 control samples were analyzed by means of standard indirect immunohistochemical technique for Fas, Fas ligand (Fas-L), tissue transglutaminase (tTG), Bcl-2, and glutathione S-transferase (GST) expression. We found significantly lower numbers of Fas-expressing enterocytes in the ACD patients than in PCD patients and controls. Similarly, the number of Fas-positive mucosal lymphocytes was decreased in ACD when compared with PCD. The number of Fas-L- and tTG-expressing enterocytes and mucosal lymphocytes was higher in both PCD and ACD. On the other hand, the number of Bcl-2-positive mucosal lymphocytes in PCD as well as ACD was significantly lower. The expression of tTG in extracellular matrix was significantly higher in PCD and ACD when compared with controls. Our results showed that Fas and/or Fas-L, Bcl-2, and tTG may be involved in apoptotic pathways leading to mucosal atrophy in children with CD. tTG changes are in agreement with the presumed role of this protein in the pathogenesis of CD.
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PMID:Immunohistochemical study of the apoptotic mechanisms in the intestinal mucosa during children's coeliac disease. 1269 66

BRCA1 is a tumor suppressor gene mutated in cases of hereditary breast and ovarian cancer. BRCA1 protein is involved in apoptosis and growth/tumor suppression. In this study, we present evidence that p65/RelA, one of the two subunits of the transcription factor NF-kappaB, binds to the BRCA1 protein. Treatment of 293T cells with the cytokine tumor necrosis factor-alpha induces an interaction between endogenous p65/RelA and BRCA1. GST-protein affinity assay experiments reveal that the Rel homology domain of the p65/RelA subunit of NF-kappaB interacts with multiple sites within the N-terminal region of BRCA1. Transient transfection of BRCA1 significantly enhances the ability of the tumor necrosis factor-alpha or interleukin-1beta to activate transcription from the promoters of NF-kappaB target genes. Mutation of the NF-kappaB-binding sites in the NF-kappaB reporter blocks the effect of BRCA1 on transcription. Also the ability of BRCA1 to activate NF-kappaB target genes is inhibited by a super-stable inhibitor of NF-kappaB and by the chemical inhibitor SN-50. These data indicate that BRCA1 acts as a co-activator with NF-kappaB. In addition, we show that cells infected with an adenovirus expressing BRCA1 up-regulate the endogenous expression of NF-kappaB target genes Fas and interferon-beta. Together, this information suggests that BRCA1 may play a role in cell life-death decisions following cell stress by modulation of the activity of NF-kappaB.
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PMID:BRCA1 augments transcription by the NF-kappaB transcription factor by binding to the Rel domain of the p65/RelA subunit. 1270 Feb 28

NF-kappaB regulates the expression of various genes involved in cell growth and differentiation, immune response and inhibition of apoptosis. Recently, some death effector domain (DED)-containing proteins, such as FADD and c-FLIP were reported to activate NF-kappaB. We previously reported that the prodomain-only isoforms of caspase-8 and -10 (PDCasp8/10), containing two DED motifs, could inhibit Fas-mediated apoptosis. Here, we demonstrate that these isoforms also activate NF-kappaB, implying this to be one of the mechanisms by which these polypeptides inhibit apoptosis. The GST pull-down assay revealed that, among upstream kinases that activate NF-kappaB, only NIK and RIP, but not RICK or IKKalpha/beta, could directly bind to PDCasp8/10. In addition, both modules ofDED in PDCasp8/10 were required for these interactions as well as NF-kappaB activation. Experiments using a kinase-dead mutant of IKKalpha and an RIP mutant lacking a kinase domain, both of which function as dominant-negative mutants for their wild-type counterparts, blocked PDCasp8/10-mediated NF-kappaB activation. Using small interfering RNA technology, we further demonstrate that the down-regulation of IKKalpha but not IKKbeta significantly inhibits PDCasp8-mediated NF-kappaB activation. Taken together, these results suggest that caspase-8 and -10 have roles in a non- or anti-apoptotic signaling pathway leading to NF-kappaB activation through RIP, NIK and IKKalpha.
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PMID:Caspase-8 and caspase-10 activate NF-kappaB through RIP, NIK and IKKalpha kinases. 1288 66

We performed a yeast two-hybrid screen using p73alpha, which is a member of the p53 family, as bait. We found that the p53 family members were functionally associated with Daxx, which was described originally as a cytoplasmic mediator of Fas signaling, but has been identified recently as a nuclear protein that co-localizes with the promyelocytic leukemia (PML) protein and regulates transcription. Extensive yeast two-hybrid assays indicated a physical interaction between a region including the oligomerization domain (OD) of p73alpha (amino acids 345-380) or p53 (amino acids 319-360) and amino acids 161-311 and 667-740 (C-terminal S/P/T-rich domain) of hDaxx, which is the common binding region of Fas, ASK1 and PML. This interaction was further confirmed by in vitro GST pull-down and in vivo immunoprecipitation assays. Both Daxx and p73/p53 co-localized in nuclear dot-like structures, which are probably nuclear PML oncogenic domains (PODs) or the nuclear domain NB10. Transient co-expression of Daxx resulted in strong inhibition of p73- and p53-mediated transcriptional activation of the synthetic p53-responsive and p21WAF1 promoters. Consequently, Gal4-Daxx repressed basal transcription in a dose-dependent manner. Treatment with trichostatin A, which is an inhibitor of histone deacetylase, or PML over-expression relieved Daxx-mediated transcriptional repression of p53. The mechanism underlying PML-mediated derepression appears to be competitive binding between Daxx, p53 and PML. Taken together, these findings delineate a transcriptional regulatory network that is modulated by differential Daxx-p53-PML interactions in the nuclear PODs. Therefore, Daxx is implicated in the regulation of the cell cycle and apoptosis through transcriptional regulation of p53 and possibly its family members.
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PMID:Identification of Daxx interacting with p73, one of the p53 family, and its regulation of p53 activity by competitive interaction with PML. 1295 72

Fas (APO-1/CD95) is a cell surface receptor that initiates apoptotic pathways, and its cytoplasmic domain interacts with various molecules suggesting that Fas signaling is complex and regulated by multiple proteins. Calmodulin (CaM) is an intracellular Ca(2+)-binding protein, and it mediates many of the effects of Ca2+. Here, we demonstrate that CaM binds to Fas directly and identify the CaM-binding site on the cytoplasmic death domain (DD) of Fas. Fas binds to CaM-Sepharose and is co-immunoprecipitated with CaM. Other death receptors, such as tumor necrosis factor receptor, DR4, and DR5 do not bind to CaM. The interaction between Fas and CaM is Ca(2+)-dependent. Deletion mapping analysis with various GST-fused Fas cytoplasmic domain fragments revealed that the fragment containing helices 1, 2, and 3 of the Fas DD has the CaM-binding ability. Sequence analysis of this fragment predicted a potential CaM-binding site in helix 2 and connected loops. A valine 254 to asparagine mutation in this region, which is analogous to the identified mutant allele of Fas in lpr mice that have a deficiency in Fas-mediated apoptosis, showed reduced CaM binding. Computer modeling of the interaction between CaM and helix 2 of the Fas DD predicted that amino acids, which are important for Fas-CaM binding, and point mutations of these amino acids caused reduced Fas-CaM binding. The interaction between Fas and CaM is increased approximately 2-fold early upon Fas activation (at 30 min) and is decreased to approximately 50% of control at 2 h. These findings suggest a novel function of CaM in Fas-mediated apoptosis.
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PMID:Calmodulin binding to the Fas death domain. Regulation by Fas activation. 1459


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