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:2.7.11.1 (protein kinase)
81,284 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Heme-hemopexin or cobalt protoporphyrin (CoPP)-hemopexin (a model ligand for hemopexin receptor occupancy) is shown to increase transcription of the metallothionein-1 (MT-1) gene by activation of a signaling pathway. Promoter deletion analysis followed by transient transfection assays show that 110 base pairs (-153 to -43) of 5'-flanking region of the murine MT-1 promoter are sufficient for increasing transcription in response to heme-hemopexin or to CoPP-hemopexin in mouse hepatoma cells. The protein kinase C inhibitor, 1-(5-isoquinolinesulfonyl)-2-methylpiperazine dihydrochloride (H7), prevented the increase in MT-1 transcription by heme-hemopexin, CoPP-hemopexin, or phorbol 12-myristate 13-acetate, but the protein kinase A inhibitor, HA1004, was without effect. N-Acetylcysteine (NAC) and glutathione, as well as superoxide dismutase and catalase, inhibited both the increase in endogenous MT-1 mRNA and the activation of reporter gene activity by heme-hemopexin, CoPP-hemopexin, and phorbol 12-myristate 13-acetate. In sum, these data suggest that reactive oxygen intermediates are generated by heme-hemopexin via events associated with receptor binding, including protein kinase C activation. Induction of heme oxygenase-1 expression, in contrast to MT-1, is significantly less sensitive to NAC. Deletion and mutation analyses of the MT-1 proximal promoter revealed that the sequence 5'-GTGACTATGC-3' (from -98 to -89 base pairs) is, in part, responsible for the hemopexin-mediated regulation of MT-1 which is inhibited by H7. Regulation via this element is also induced by H2O2 showing that it is an antioxidant response element. Heme itself acts via more distal elements on the MT-1 promoter. In contrast to NAC and glutathione, diethyl dithiocarbamate and pyrrolidine dithiocarbamate, which inactivate reactive oxygen intermediates and chelate Zn(II), synergistically augment the induction of MT-1 mRNA levels and reporter gene activity in response to heme-hemopexin via the antioxidant response element by both metal-responsive element-dependent and -independent mechanisms.
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PMID:Mechanism of metallothionein gene regulation by heme-hemopexin. Roles of protein kinase C, reactive oxygen species, and cis-acting elements. 759 95

We examined the effect of insulin on nuclear factor kappa B (NF-kappa B) activity in Chinese ovary (CHO) cells overexpressing wild-type (CHO-R cells) or -defective insulin receptors mutated at Tyr1162 and Tyr1163 autophosphorylation sites (CHO-Y2 cells). In CHO-R cells, insulin caused a specific, time-, and concentration-dependent activation of NF-kappa B. The insulin-induced DNA-binding complex was identified as the p50/p65 heterodimer. Insulin activation of NF-kappa B: 1) was related to insulin receptor number and tyrosine kinase activity since it was markedly reduced in parental CHO cells which proved to respond to insulin growth factor-1 and phorbol 12-myristate 13-acetate (PMA) activation, and was dramatically decreased in CHO-Y2 cells; 2) persisted in the presence of cycloheximide and was blocked by pyrrolidine dithiocarbamate, aspirin and sodium salicylate, three compounds interfering with I kappa B degradation and/or NF-kappa B.I kappa B complex dissociation; 3) was independent of both PMA-sensitive and atypical (zeta) protein kinases C; and 4) was dependent on Raf-1 kinase activity since insulin-stimulated NF-kappa B DNA binding activity was inhibited by 8-bromo-cAMP, a Raf-1 kinase inhibitor. Moreover, insulin activation of NF-kappa B-driven luciferase reporter gene expression was blocked in CHO-R cells expressing a Raf-1 dominant negative mutant. This is the first evidence that insulin activates NF-kappa B in mammalian cells through a post-translational mechanism requiring both insulin receptor tyrosine kinase and Raf-1 kinase activities.
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PMID:Insulin activates nuclear factor kappa B in mammalian cells through a Raf-1-mediated pathway. 759 58

A series of balanol analogs in which the perhydroazepine ring and the p-hydroxybenzamide moiety were combined into an acyclic linked unit have been prepared and evaluated for their inhibitory properties against the serine/threonine kinase PKC. Several low-micromolar to low-nanomolar inhibitors of the alpha, beta I, beta II, gamma, delta, epsilon and eta PKC isozymes were prepared. In general, these acyclic balanol analogs were found to be highly selective for PKC over the serine/threonine kinase PKA. The type and number of atoms linking the benzophenone ester to the p-hydroxyphenyl group necessary for optimal PKC inhibition were investigated. The most potent compounds contained a three-carbon linker in which the carboxamide moiety of balanol had been replaced by a methylene group. The effect of placing substituents on the three-carbon chain was also investigated. The preferred compounds contained either a 2-benzenesulfonamido (6b) or a 1-methyl (21b) substituent. The preferred compounds 6b and 21b were tested against a panel of serine/threonine kinases and found to be highly selective for PKC. The more active enantiomer of 6b, (S)-12b, was 3-10-fold more active than the R-enantiomer against the PKC isozymes. The effect of making the analogs more rigid by making the three-carbon chain part of a five-membered ring, but with retention of the methylene replacement for the carboxamide moiety, led to potent PKC inhibitors including anti-substituted pyrrolidine analog 35b and the most potent PKC inhibitor in the series, anti-substituted cyclopentane analog 29b. The anti cyclopentane analog 29b, was a low-micromolar inhibitor of the PMA-induced superoxide burst in neutrophils, and its carboxylic ester was a high-nanomolar inhibitor of neutrophils. Finally esterification of 21b, (S)-12b, and 35b turned these potent PKC inhibitors into low-micromolar inhibitors of neutrophils.
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PMID:Synthesis and protein kinase C inhibitory activities of acyclic balanol analogs that are highly selective for protein kinase C over protein kinase A. 897 50

Previously, our laboratory reported that lactosylceramide (LacCer) stimulated human aortic smooth muscle cell proliferation via specific activation of p44 mitogen-activated protein kinase (MAPK) in the p21(ras)/Raf-1/MEK2 pathway and induced expression of the transcription factor c-fos downstream to the p44 MAPK signaling cascade (Bhunia A. K., Han, H., Snowden, A., and Chatterjee S. (1996) J. Biol. Chem. 271, 10660-10666). In the present study, we explored the role of free oxygen radicals in LacCer-mediated induction of cell proliferation. Superoxide levels were measured by the lucigenin chemiluminescence method, MAPK activity was measured by immunocomplex kinase assays, and Western blot analysis and c-fos expression were measured by Northern blot assay. We found that LacCer (10 microM) stimulates endogenous superoxide production (7-fold compared with control) in human aortic smooth muscle cells specifically by activating membrane-associated NADPH oxidase, but not NADH or xanthine oxidase. This process was inhibited by an inhibitor of NADPH oxidase, diphenylene iodonium (DPI), and by antioxidants, N-acetyl-L-cysteine (NAC) or pyrrolidine dithiocarbamate. NAC and DPI both abrogated individual steps in the signaling pathway leading to cell proliferation. For example, the p21(ras).GTP loading, p44 MAPK activity, and induction of transcription factor c-fos all were inhibited by NAC and DPI as well as an antioxidant pyrrolidine dithiocarbamate or reduced glutathione (GSH). In contrast, depletion of GSH by L-buthionine (S, R)-sulfoximine up-regulated the above described signaling cascade. In sum, LacCer, by virtue of activating NADPH oxidase, produces superoxide (a redox stress signaling molecule), which mediates cell proliferation via activation of the kinase cascade. Our findings may explain the potential role of LacCer in the pathogenesis of atherosclerosis involving the proliferation of aortic smooth muscle cells.
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PMID:Redox-regulated signaling by lactosylceramide in the proliferation of human aortic smooth muscle cells. 918 53

The interleukin-1 receptor type I (IL-1RI) is associated with other proteins thus forming a complex system by which IL-1 exerts its various signals. The initiating event is still uncertain, but activation of a recently described receptor-associated protein kinase is one of the earliest events detectable (Martin et al., Eur. J. Immunol. 1994. 24: 1566). IL-1 signaling is commonly accompanied by oxidative processes and is thought to be subject to redox regulation. We therefore investigated whether the activation of the IL-1RI-associated protein kinase could be a target for redox regulation and whether an altered activity of the kinase could influence IL-1-mediated NF-kappa B activation. A murine T cell line, EL4, was stimulated with IL-1 with and without pretreatment with different compounds known to influence the cellular redox status. Thiol modifying agents like diamide, menadione, pyrrolidine dithiocarbamate (PDTC), diethyl dithiocarbamate or phenylarsine oxide inhibited the IL-1-induced activation of the IL-1RI-associated protein kinase. N-Acetylcysteine, alpha,alpha'-dipyridyl, aminotriazole or nitrofurantoin did not show any effect. The inhibition by PDTC was reversible unless glutathione synthesis was blocked by buthionine sulfoximine. The described conditions which inhibited or prevented the activation of the IL-1RI-associated kinase similarly impaired the activation of NF-kappa B in EL4 cells. From these observations we conclude that free thiols in the IL-1RI complex are essential for the activation of the IL-1RI-associated protein kinase and that this process is mandatory for IL-1 signaling leading to NF-kappa B activation.
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PMID:Thiol modulation inhibits the interleukin (IL)-1-mediated activation of an IL-1 receptor-associated protein kinase and NF-kappa B. 939 32

Studies on the mechanisms of inducible and constitutive activity of NF-kappaB transcription factors have been hampered by the lack of appropriate mutant cell lines. We have analyzed the defect in the murine S107 plasmacytoma cell line, which was previously found to lack both constitutive and inducible NF-kappaB activity. Our analysis shows that these cells bear a specific defect that interferes with NF-kappaB induction by many diverse stimuli, such as lipopolysaccharide, phorbol 12-myristate 13-acetate, UV light, x-rays, and H2O2. This does not however represent a general signal transduction defect, because AP-1 transcription factors are readily induced by the same stimuli. Phosphatase inhibitors such as okadaic acid as well as calyculin A can efficiently induce NF-kappaB in S107 cells via a pathway apparently insensitive to the radical scavenger pyrrolidine dithiocarbamate. Furthermore, MEKK1 a protein kinase supposedly induced by some of the above stimuli, is also capable of activating NF-kappaB. Interestingly, both the potent physiological inducer of NF-kappaB TNFalpha as well as endoplasmic reticulum overload can induce NF-kappaB via a PDTC sensitive pathway. In all cases, DNA-binding NF-kappaB complexes are comprised predominantly of p50-RelA heterodimers, and NF-kappaB activation results in the induction of transiently transfected or resident reporter genes. In summary, these results suggest that the pathways for many NF-kappaB-inducing stimuli converge at a specific junction, and this pivotal step is mutated in the S107 cell line. Yet there are alternative routes bypassing this critical step that also lead to NF-kappaB induction. These routes utilized by tumor necrosis factor alpha and endoplasmic reticulum overload are still intact in this cell line.
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PMID:The mutant plasmacytoma cell line S107 allows the identification of distinct pathways leading to NF-kappaB activation. 956 56

The mechanism of the expression of intercellular adhesion molecule-1 (ICAM-1) on epithelial cells was analyzed using NCI-H292 cells, a human bronchial epithelial cell line. Treatment with interferon-gamma (100 U/ml) or the protein kinase C activator 12-O-tetradecanoylphorbol 13-acetate (TPA) (16.2 nM) induced ICAM-1 expression. The interferon-gamma-induced ICAM-1 expression was reduced by the tyrosine kinase inhibitor genistein (4',5,7-trihydroxyisoflavone) (37 to 185 microM), but not by the protein kinase C inhibitor Ro 31-8425 ((3-[8-(aminomethyl)-6,7,8,9-tetrahydropyrido [1.2-a]indol-10-yl]-4-(1-methyl-1 H-pyrrole-2,3-dione) (10 microM). The TPA-induced ICAM-1 expression was reduced by the protein kinase C inhibitor Ro 31-8425 (1 to 10 microM), but not by the tyrosine kinase inhibitor genistein (185 microM). The protein kinase A inhibitor H-89 (N-[2-((p-bromocinnamyl)amino)ethyl]-5-isoquinolinesulfonamide) did not affect the ICAM-1 expression induced by interferon-gamma or TPA. Pyrrolidine dithiocarbamate (1-pyrrolidinecarbodithioic acid) (100 microM), an inhibitor of nuclear factor kappaB (NF-kappaB) activation. enhanced the ICAM-1 expression induced by interferon-y, but reduced that induced by TPA. The changes in ICAM-1 expression on the cell surface were correlated with the changes in ICAM-1 mRNA levels. Combined treatment with interferon-gamma and TPA induced more than additive ICAM-1 expression. These findings suggest that interferon-gamma induces ICAM-1 expression by a tyrosine kinase-dependent mechanism, but that TPA induces it by a protein kinase C- and NF-kappaB-dependent mechanism.
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PMID:Analysis of the expression of intercellular adhesion molecule-1 in cells of the human bronchial epithelial cell line NCI-H292. 960 Jun 38

We examined the effect of an antioxidant and protein kinase inhibitors on prostaglandin E2 (PGE2) release from Balb/c 3T3 mouse fibroblast cells induced by quinolone phototoxicity. Simultaneous administration of sparfloxacin (SPFX) or lomefloxacin (LFLX) at 12.5 to 100 microM and ultraviolet-A (UVA) irradiation for 10 min markedly elevated PGE2 concentration in the incubation medium, whereas levofloxacin (LVFX) at concentrations up to 100 microM and UVA irradiation did not increase PGE2 concentration. Pretreatment with 100 microM pyrrolidine dithiocarbamate (PDTC), an antioxidant, or 1 microM calphostin C, a selective inhibitor of protein kinase C (PKC), completely inhibited the elevation of PGE2 in the 24-h incubation medium; pretreatment with 10 microM H7, a cyclic nucleotide-dependent protein kinase, and PKC or 1 microM herbimycin A, a tyrosine kinase inhibitor, inhibited the PGE2 elevation by 29 to 39%. Conversely, 25 nM staurosporine significantly augmented the PGE2 elevation by quinolones plus UVA. Interleukin-1beta (IL-1beta) and tumor necrosis factor alpha (TNFalpha) were not detected in the incubation medium of 3T3 cells after quinolone plus UVA, corresponding to the lack of effect of antibodies against IL-1alpha, IL-1beta, and TNFalpha on PGE2 release from 3T3 cells. These results suggest that PGE2 production in 3T3 cells by quinolone phototoxicity is modulated by reactive oxygen species, PKC, and tyrosine kinase, but not by IL-1 or TNFalpha.
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PMID:Involvement of reactive oxygen species, protein kinase C, and tyrosine kinase in prostaglandin E2 production in Balb/c 3T3 mouse fibroblast cells by quinolone phototoxicity. 963 9

Bovine retinal pigmented epithelial cells express an inducible nitric oxide synthase (NOS-2) after activation with interferon-gamma (IFN-gamma) and lipopolysaccharide (LPS). Experiments were performed to investigate the involvement of interferon regulatory factor-1 (IRF-1) on NOS-2 induction and its regulation by NOS-2 inhibitors such as pyrrolidine dithiocarbamate (PDTC), an antioxidant, or protein kinase inhibitors. Analysis by transitory transfections showed that LPS, alone or with IFN-gamma, stimulated activity of the murine NOS-2 promoter fragment linked upstream of luciferase and its suppression by PDTC and by the different protein kinase inhibitors, genistein (tyrosine kinase inhibitor), PD98059 (mitogen-actived protein (MAP) kinase kinase inhibitor), and SB 203580 (p38 MAP inhibitor). Using specific antibodies, we have confirmed that extracellular signal-regulated kinases and p38 MAP kinase were activated by LPS and IFN-gamma in retinal pigmented epithelial cells. Analysis by reverse transcriptase-polymerase chain reaction, Western blot, and electrophoretic mobility shift assay demonstrated that IFN-gamma alone or combined with LPS induced an accumulation of IRF-1 mRNA and protein and IRF-1 DNA binding. Transfections assays with the IRF-1 promoter showed an induction of this promoter with IFN-gamma, potentiated by LPS. The decrease of LPS/IFN-gamma-induced IRF-1 promoter activity, IRF-1 synthesis, and IRF-1 activation, by PDTC, genistein, PD98059, and SB 203580, could explained in part the inhibition of the NOS-2 induction by these compounds. Our results demonstrate that IRF-1 is necessary for NOS-2 induction by LPS and IFN-gamma and that its synthesis requires the involvement of a redox-sensitive step, the activation of tyrosine kinases, and extracellular signal-regulated kinases 1/2 and p38 MAP kinases.
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PMID:Role of interferon regulatory factor-1 and mitogen-activated protein kinase pathways in the induction of nitric oxide synthase-2 in retinal pigmented epithelial cells. 998 18

This study examined the role of the protein kinase C (PKC) signalling pathway in the regulation of expression of human complement factor I (CFI) gene. The production of CFI by Hep G2 cells was enhanced in a dose- and time-dependent fashion by 12-O-tetradecanoyl-1,2-phorbol 13-acetate (TPA), a potent PKC activator. 4Alpha-phorbol didecanoate, an inactive phorbol ester, had no effect on CFI synthesis. The TPA-dependent increase in CFI secretion was correlated with an increase in CFI mRNA levels. Forskolin, a cAMP-inducing agent, augmented the TPA response. W7, an inhibitor of protein kinase A and genistein, an inhibitor of protein tyrosine kinase(s) both did not prevent the increase in CFI expression mediated by TPA. However, calphostin C, a specific inhibitor of PKC, abolished the TPA-induced increase in CFI mRNA levels. Down regulation of intracellular PKC levels by prior exposure of Hep G2 cells to a high concentration of TPA also blocked the increase in CFI mRNA levels induced by TPA suggesting that the TPA effects were mediated via activation of PKC. mRNA decay studies indicated that the half-life of CFI mRNA in TPA-induced cells was not significantly different from control. Nuclear run-on transcriptional assays on the other hand demonstrated that whereas the CFI gene is transcribed under basal conditions in Hep G2 cells, TPA induced a 3-4 fold increase in the transcription rate of CFI gene in 24 h. The transcription rate of GAPDH gene did not change, indicating that the effects were not general on gene transcription. Transient transfections of Hep G2 cells with chloramphenicol acetyltransferase reporter gene (CAT) constructs containing a series of sequential 5' deletions of the CFI promoter and CAT assays showed that the sequence between -136 and -130, containing an AP-1 consensus sequence (TGAGTCA) was required for the TPA response. This observation was substantiated by the finding that mutation of this AP-1 site to TttaTCA or TtAtcCA abolished the TPA responsiveness. The enhancement of the activity of transfected chimeric CAT constructs by TPA was abrogated by calphostin C and by pyrrolidine dithiocarbamate (an inhibitor of NF-kappaB and AP-1 transactivation). These results indicate that TPA regulation of CFI gene requires PKC signalling and is mediated by via a TPA response element (TRE) in the CFI promoter region located at -136/-130 and involves the transactivation of AP-1 and NF-kappaB transcription factors. We suggest that PKC may be one of the intracellular pathways that control CFI gene expression and that cellular processes (involving growth factors, hormones, cytokines etc.) that activate PKC may upregulate the expression of the CFI gene.
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PMID:Transcriptional modulation of the human complement factor I gene in Hep G2 cells by protein kinase C activation. 1063 Jun 30


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