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

---

Query: EC:2.5.1.18 (glutathione S-transferase)
22,582 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Translation initiation factor (eIF) 4G represents a critical link between mRNAs and 40S ribosomal subunits during translation initiation. It interacts directly with the cap-binding protein eIF4E through its N-terminal part, and binds eIF3 and eIF4A through the central and C-terminal region. We expressed and purified recombinant variants of human eIF4G lacking the N-terminal domain as GST-fusion proteins, and studied their function in cell-free translation reactions. Both eIF4G lacking its N-terminal part (aa 486-1404) and the central part alone (aa 486-935) exert a dominant negative effect on the translation of capped mRNAs. Furthermore, these polypeptides potently stimulate the translation of uncapped mRNAs. Although this stimulation is cap-independent, it is shown to be dependent on the accessibility of the mRNA 5' end. These results reveal two unexpected features of eIF4G-mediated translation. First, the C-terminal eIF4A binding site is dispensable for activation of uncapped mRNA translation. Second, translation of uncapped mRNA still requires 5' end-dependent ribosome binding. These new findings are incorporated into existing models of mammalian translation initiation.
...
PMID:Translational activation of uncapped mRNAs by the central part of human eIF4G is 5' end-dependent. 967 Oct 55

eIF1 is a universally conserved translation factor that is necessary for scanning and involved in initiation site selection. We have determined the solution structure of human eIF1 with an N-terminal His tag using NMR spectroscopy. Residues 29-113 of the native sequence form a tightly packed domain with two alpha-helices on one side of a five-stranded parallel and antiparallel beta-sheet. The fold is new but similar to that of several ribosomal proteins and RNA-binding domains. A likely binding site is indicated by yeast mutations and conserved residues located together on the surface. No interaction with recombinant eIF5 or the initiation site RNA GCCACAAUGGCA was detected by NMR, but GST pull-down experiments show that eIF1 binds specifically to the p110 subunit of eIF3. This interaction explains how eIF1 is recruited to the 40S ribosomal subunit.
...
PMID:Structure and interactions of the translation initiation factor eIF1. 1022 74

Erythroid protein 4.1 (4.1R) is an 80-kd cytoskeletal protein that stabilizes the membrane-skeletal network structure underlying the lipid bilayer. Using the carboxyl terminal domain (22/24 kd) of 4.1R as bait in a yeast 2-hybrid screen, we isolated cDNA clones encoding a polypeptide of eIF3-p44, which represents a subunit of a eukaryotic translation initiation factor 3 (eIF3) complex. The eIF3 complex consists of at least 10 subunits that play an essential role in the pathway of protein translation initiation. Northern blot analysis revealed that eIF3-p44 (approximately 1.35 kb) is constitutively expressed in many tissues. The essential sequence for this interaction was mapped to the carboxyl-terminus of 4.1R (residues 525-622) and a region (residues 54-321) of eIF3-p44. The direct association between 4.1R and eIF3-p44 was further confirmed by in vitro binding assays and coimmunoprecipitation studies. To characterize the functions of eIF3-p44, we depleted eIF3-p44 from rabbit reticulocyte lysates either by anti-eIF3-p44 antibody or by GST/4.1R-80 fusion protein. Our results show that the eIF3-p44 depleted cell-free translation system was unable to synthesize proteins efficiently. The direct association between 4.1R and elF3-p44 suggests that 4.1R may act as an anchor protein that links the cytoskeleton network to the translation apparatus. (Blood. 2000;96:747-753)
...
PMID:Protein 4.1R binding to eIF3-p44 suggests an interaction between the cytoskeletal network and the translation apparatus. 1088 44

The protein kinase PKR (dsRNA-dependent protein kinase) phosphorylates the eukaryotic translation initiation factor eIF2alpha to downregulate protein synthesis in virus-infected cells. Two double-stranded RNA binding domains (dsRBDs) in the N-terminal half of PKR are thought to bind the activator double-stranded RNA, mediate dimerization of the protein and target PKR to the ribosome. To investigate further the importance of dimerization for PKR activity, fusion proteins were generated linking the PKR kinase domain to heterologous dimerization domains. Whereas the isolated PKR kinase domain (KD) was non-functional in vivo, expression of a glutathione S-transferase-KD fusion, or co-expression of KD fusions containing the heterodimerization domains of the Xlim-1 and Ldb1 proteins, restored PKR activity in yeast cells. Finally, coumermycin-mediated dimerization of a GyrB-KD fusion protein increased eIF2alpha phosphorylation and inhibited reporter gene translation in mammalian cells. These results demonstrate the critical importance of dimerization for PKR activity in vivo, and suggest that a primary function of double-stranded RNA binding to the dsRBDs of native PKR is to promote dimerization and activation of the kinase domain.
...
PMID:Heterologous dimerization domains functionally substitute for the double-stranded RNA binding domains of the kinase PKR. 1144 14

Mammalian target of rapamycin (mTOR) controls initiation of translation through regulation of ribosomal p70S6 kinase (S6K1) and eukaryotic translation initiation factor-4E (eIF4E) binding protein (4E-BP). mTOR is considered to be located predominantly in cytosolic or membrane fractions and may shuttle between the cytoplasm and nucleus. In most previous studies a single cell line, E1A-immortalized human embryonic kidney cells (HEK293), has been used. Here we show that in human malignant cell lines, human fibroblasts, and murine myoblasts mTOR is predominantly nuclear. In contrast, mTOR is largely excluded from the nucleus in HEK293 cells. Hybrids between HEK293 and Rh30 rhabdomyosarcoma cells generated cells co-expressing markers unique to HEK293 (E1A) and Rh30 (MyoD). mTOR distribution was mainly nuclear with detectable levels in the cytoplasm. mTOR isolated from Rh30 nuclei phosphorylated recombinant GST-4E-BP1 (Thr-46) in vitro and thus has kinase activity. We next investigated the cellular distribution of mTOR substrates 4E-BP, S6K1, and eIF4E. 4E-BP was exclusively detected in cytoplasmic fractions in all cell lines. S6K1 was localized in the cytoplasm in colon carcinoma, HEK293 cells, and IMR90 fibroblasts. S6K1 was readily detected in all cellular fractions derived from rhabdomyosarcoma cells. eIF4E was detected in all fractions derived from rhabdomyosarcoma cells but was not detectable in nuclear fractions from colon carcinoma HEK293 or IMR90 cells.
...
PMID:Predominant nuclear localization of mammalian target of rapamycin in normal and malignant cells in culture. 1200 Jul 55

Programmed cell death 4 (PDCD4) has a common MI domain sharing with death associated protein 5 (DAP5) and a component of eukaryotic translation initiation factor (eIF4G) complex and it might also work as a tumor suppressor. We could find that the message and product of Pdcd4 gene were up-regulated in senescent human diploid fibroblasts. In yeast two hybrid analysis, the C-terminal region of PDCD4 interacted with ribosomal protein S13 (RPS13), ribosomal protein L5 (RPL5), and TI-227H. In in vitro binding assay, RPS13, a component of 40S ribosome was stably bound to PDCD4. We also found that PDCD4 was localized to polysome fractions. We could pull out eIF4G with GST-PDCD4, but eIF4E did not interact with PDCD4. From these results, we could assume that PDCD4 might regulate the eIF4G-dependent translation through direct interactions with eIF4G and RPS13 in senescent fibroblasts.
...
PMID:Up-regulation of PDCD4 in senescent human diploid fibroblasts. 1205 47

Mammalian translation initiation factor 3 (eIF3) is a multisubunit complex containing at least 12 subunits with an apparent aggregate mass of approximately 700 kDa. eIF3 binds to the 40S ribosomal subunit, promotes the binding of methionyl-tRNAi and mRNA, and interacts with several other initiation factors to form the 40S initiation complex. Human cDNAs encoding 11 of the 12 subunits have been isolated previously; here we report the cloning and characterization of a twelfth subunit, a 28-kDa protein named eIF3k. Evidence that eIF3k is present in the eIF3 complex was obtained. A monoclonal anti-eIF3a (p170) Ig coimmunoprecipitates eIF3k with the eIF3 complex. Affinity purification of histidine-tagged eIF3k from transiently transfected COS cells copurifies other eIF3 subunits. eIF3k colocalizes with eIF3 on 40S ribosomal subunits. eIF3k coexpressed with five other 'core' eIF3 subunits in baculovirus-infected insect cells, forms a stable, immunoprecipitatable, complex with the 'core'. eIF3k interacts directly with eIF3c, eIF3g and eIF3j by glutathione S-transferase pull-down assays. Sequences homologous with eIF3k are found in the genomes of Caenorhabitis elegans, Arabidopsis thaliana and Drosophila melanogaster, and a homologous protein has been reported to be present in wheat eIF3. Its ubiquitous expression in human tissues, yet its apparent absence in Saccharomyces cerevisiae and Schizosaccharomyces pombe, suggest a unique regulatory role for eIF3k in higher organisms. The studies of eIF3k complete the characterization of mammalian eIF3 subunits.
...
PMID:Characterization of eIF3k: a newly discovered subunit of mammalian translation initiation factor elF3. 1451 25

Glycogen synthase kinase 3beta (GSK-3beta) negatively regulates cardiac hypertrophy. A potential target mediating the antihypertrophic effect of GSK-3beta is eukaryotic translation initiation factor 2Bepsilon (eIF2Bepsilon). Overexpression of GSK-3beta increased the cellular kinase activity toward GST-eIF2Bepsilon in neonatal rat cardiac myocytes, whereas LiCl (10 mmol/L) or isoproterenol (ISO) (10 micromol/L), a treatment known to inhibit GSK-3beta, decreased it. Immunoblot analyses using anti-S535 phosphospecific eIF2Bepsilon antibody showed that S535 phosphorylation of endogenous eIF2Bepsilon was decreased by LiCl or ISO, suggesting that GSK-3beta is the predominant kinase regulating phosphorylation of eIF2Bepsilon-S535 in cardiac myocytes. Decreases in eIF2Bepsilon-S535 phosphorylation were also observed in a rat model of cardiac hypertrophy in vivo. Overexpression of wild-type eIF2Bepsilon alone moderately increased cell size (+31+/-11%; P<0.05 versus control), whereas treatment of eIF2Bepsilon-transduced myocytes with LiCl (+73+/-22% versus eIF2Bepsilon only; P<0.05) or ISO (+84+/-33% versus eIF2Bepsilon only; P<0.05) enhanced the effect of eIF2Bepsilon. Overexpression of eIF2Bepsilon-S535A, which is not phosphorylated by GSK-3beta, increased cell size (+107+/-35%) as strongly as ISO (+95+/-25%), and abolished antihypertrophic effects of GSK-3beta, indicating that S535 phosphorylation of eIF2Bepsilon critically mediates antihypertrophic effects of GSK-3beta. Furthermore, expression of eIF2Bepsilon-F259L, a dominant-negative mutant, inhibited ISO-induced hypertrophy, indicating that eIF2Bepsilon is required for beta-adrenergic hypertrophy. Interestingly, expression of eIF2Bepsilon-S535A partially increased cytoskeletal reorganization, whereas it did not increase expression of atrial natriuretic factor gene. These results suggest that GSK-3beta is the predominant kinase mediating phosphorylation of eIF2Bepsilon-S535 in cardiac myocytes, which in turn plays an important role in regulating cardiac hypertrophy primarily through protein synthesis.
...
PMID:Phosphorylation of eukaryotic translation initiation factor 2Bepsilon by glycogen synthase kinase-3beta regulates beta-adrenergic cardiac myocyte hypertrophy. 1500 29

cAMP response element-binding protein (CREB)-binding protein (CBP) plays an important role as a general co-integrator of multiple signaling pathways and interacts with a large number of transcription factors and co-factors, through its numerous protein-binding domains. To identify nuclear factors associated with CBP in developing orofacial tissue, a yeast two-hybrid screen of a cDNA library derived from orofacial tissue from gestational day 11 to 13 mouse embryos was conducted. Using the carboxy terminus (amino acid residues 1676-2441) of CBP as bait, several novel proteins that bind CBP were identified, including an Msx-interacting-zinc finger protein, CDC42 interaction protein 4/thyroid hormone receptor interactor 10, SH3-domain GRB2-like 1, CCR4-NOT transcription complex subunit 3, adaptor protein complex AP-1 beta1 subunit, eukaryotic translation initiation factor 2B subunit 1 (alpha), and cyclin G-associated kinase. Results of the yeast two-hybrid screen were confirmed by glutathione S-transferase pull-down assays. The identification of these proteins as novel CBP-binding partners allows exploration of new mechanisms by which CBP regulates and integrates diverse cell signaling pathways.
...
PMID:Identification of novel CBP interacting proteins in embryonic orofacial tissue. 1575 56

We previously isolated a monoclonal antibody named PH2 that inhibits phosphatidylserine-mediated phagocytosis of apoptotic cells by macrophages. We report here the identification of the cognate antigen. A protein bound by PH2 in Western blotting was identified as the 170-kDa subunit of eukaryotic translation initiation factor 3 (eIF3 p170/eIF3a). When eIF3a was expressed in a culture cell line as a protein fused to green fluorescence protein, the fusion protein was detected at the cell surface only after the induction of apoptosis. The same phenomenon was seen when the localization of endogenous eIF3a was determined using anti-eIF3a antibody, and eIF3a seemed to be partially degraded during apoptosis. Furthermore, bacterially expressed N-terminal half of eIF3a fused to glutathione S-transferase bound to the surface of macrophages and inhibited phagocytosis of apoptotic cells by macrophages when it was added to phagocytosis reactions. These results collectively suggest that eIF3a translocates to the cell surface upon apoptosis, probably after partial degradation, and bridges apoptotic cells and macrophages to enhance phagocytosis.
...
PMID:Externalization and recognition by macrophages of large subunit of eukaryotic translation initiation factor 3 in apoptotic cells. 1597 69


1 2 Next >>

---