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: UNIPROT:P05412 (c-Jun)
11,453 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Hypoxia and reoxygenation are principal components of myocardial ischemia and reperfusion and have distinctive effects on the tissue. Both conditions have been associated with inflammation, necrosis, apoptosis, and myocardial infarction. Using a cell culture model of ischemia and reperfusion in which cardiac myocytes were exposed to cycles of hypoxia and reoxygenation, we report here that reoxygenation, but not hypoxia alone, caused sustained approximately 10-fold increases in phosphorylation of the amino-terminal domain of the c-jun transcription factor. The activation was similar to treatments with anisomycin or okadaic acid and correlated with the hypoxia-mediated depression of intracellular glutathione. Reoxygenation-induced c-Jun kinase activity was reduced by preincubating myocytes during the hypoxia phase with the spin-trap agent alpha-phenyl N-tert-butylnitrone or with N-acetylcysteine. The kinase activation was also inhibited by the tyrosine kinase inhibitor genistein but not by other protein kinase inhibitors. These results implicate unquenched reactive oxygen intermediates as the stimulus that initiates a kinase pathway involving the stress-activated protein kinases (JNKs/SAPKs) in reoxygenated cardiac myocytes.
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PMID:Hypoxia/reoxygenation stimulates Jun kinase activity through redox signaling in cardiac myocytes. 904 53

Stimulation of high affinity IgE Fc receptors (FcepsilonRI) in basophils and mast cells activates the tyrosine kinases Lyn and Syk and causes the tyrosine phosphorylation of phospholipase C-gamma, resulting in the Ca2+- and protein kinase C-dependent secretion of inflammatory mediators. Concomitantly, FcepsilonRI stimulation initiates a number of signaling events resulting in the activation of mitogen-activated protein kinase (MAPK) and c-Jun NH2-terminal kinase (JNK), which, in turn, regulate nuclear responses, including cytokine gene expression. To dissect the signaling pathway(s) linking FcepsilonRI to MAPK and JNK, we reconstructed their respective biochemical routes by expression of a chimeric interleukin-2 receptor alpha subunit (Tac)-FcepsilonRI gamma chain (Tacgamma) in COS-7 cells. Cross-linking of Tacgamma did not affect MAPK in COS-7 cells, but when coexpressed with the tyrosine kinase Syk, Tacgamma stimulation potently induced Syk and Shc tyrosine phosphorylation and MAPK activation. In contrast, Tacgamma did not signal JNK activation, even when coexpressed with Syk. Ectopic expression of a hematopoietic-specific guanine nucleotide exchange factor (GEF), Vav, reconstituted the Tacgamma-induced, Syk- and Rac1-dependent JNK activation; and tyrosine-phosphorylation of Vav by Syk stimulated its GEF activity for Rac1. Thus, these data strongly suggest that Vav plays a critical role linking FcepsilonRI and Syk to the Rac1-JNK pathway. Furthermore, these findings define a novel signal transduction pathway involving a multimeric cell surface receptor acting on a cytosolic tyrosine kinase, which, in turn, phosphorylates a GEF, thereby regulating its activity toward a small GTP-binding protein and promoting the activation of a kinase cascade.
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PMID:Tyrosine phosphorylation of the vav proto-oncogene product links FcepsilonRI to the Rac1-JNK pathway. 909 26

We studied the signal transduction mechanism that is involved in c-Jun phosphorylation evident after glucose deprivation in MCF-7/ADR cells. Glucose deprivation caused an immediate increase in tyrosine phosphorylation in MCF-7/ADR cells and specifically activated Lyn kinase, a src family tyrosine kinase. In addition, hypoglycemic treatment strongly activated c-Jun N-terminal kinase 1 (JNK1), leading to the phosphorylation and activation of c-Jun. Experiments with Lyn antisense oligonucleotides demonstrated that Lyn kinase activation was responsible for the activation of JNK1 but not extracellular signal-regulated kinase. We also observed glucose deprivation-induced Ras activation in MCF-7/ADR cells. These results indicate a possible Ras-dependent signaling pathway involving Lyn kinase and JNK1, which leads to the glucose deprivation-induced responses in MCF-7/ADR cells.
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PMID:Hypoglycemia-induced c-Jun phosphorylation is mediated by c-Jun N-terminal kinase 1 and Lyn kinase in drug-resistant human breast carcinoma MCF-7/ADR cells. 911 18

1. Extracellular adenosine 5'-triphosphate (ATP) and uridine 5'-triphosphate (UTP) have been shown to activate a nucleotide receptor (P2U receptor) in rat mesangial cells that mediates phosphoinositide and phosphatidylcholine hydrolysis by phospholipases C and D, respectively. This is followed by an increased activity of the mitogen-activated protein kinase cascade and cell proliferation. Here we show that ATP and UTP potently stimulate the stress-activated protein kinase pathway and phosphorylation of the transcription factor c-Jun. 2. Both nucleotides stimulated a rapid (within 5 min) and concentration-dependent activation of stress-activated protein kinases as measured by the phosphorylation of c-Jun in a solid phase kinase assay. 3. When added at 100 microM the rank order of potency of a series of nucleotide analogues for stimulation of c-Jun phosphorylation was UTP > ATP = UDP = ATP gamma S > 2-methylthio-ATP > beta gamma-imido-ATP = ADP > AMP = UMP = adenosine = uridine. Activation of stress-activated protein kinase activity by ATP and UTP was dose-dependently attenuated by suramin. 4. Down-regulation of protein kinase C-alpha, -delta and -epsilon isoenzymes by 24 h treatment of the cells with 12-O-tetradecanoylphorbol 13-acetate did not inhibit ATP- and UTP-induced activation of c-Jun phosphorylation. Furthermore, the specific protein kinase C inhibitors, CGP 41251 and Ro 31-8220, did not inhibit nucleotide-stimulated c-Jun phosphorylation, suggesting that protein kinase C is not involved in ATP- and UTP-triggered stress-activated protein kinase activation. 5. Pretreatment of the cells with pertussis toxin or the tyrosine kinase inhibitor, genistein, strongly attenuated ATP- and UTP-induced c-Jun phosphorylation. Furthermore, N-acetyl-cysteine completely blocked the activation of stress-activated protein kinase in response to extracellular nucleotide stimulation. 6. In summary, these results suggest that ATP and UTP trigger the activation of the stress-activated protein kinase module in mesangial cells by a pathway independent of protein kinase C but requiring a pertussis toxin-sensitive G-protein and tyrosine kinase activation.
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PMID:Stimulation by extracellular ATP and UTP of the stress-activated protein kinase cascade in rat renal mesangial cells. 913 85

The c-Abl nonreceptor tyrosine kinase and the c-Jun NH2-terminal kinase (JNK/stress-activated protein kinase) are activated during the injury response to the DNA-damaging agent cisplatin. Loss of DNA mismatch repair activity results in resistance to cisplatin in human cancer cells, suggesting that the mismatch repair proteins function as a detector for cisplatin DNA adducts. To identify signaling pathways activated by this detector, we investigated the effect of the loss of DNA mismatch repair function on the ability of cisplatin to activate the JNK and c-Abl kinases. The results demonstrate that cisplatin activates JNK kinase 3.8 +/- 0.2-fold more efficiently in DNA mismatch repair-proficient than repair-deficient cells, and that activation of c-Abl is completely absent in the DNA mismatch repair-deficient cells. Furthermore, the results show that cisplatin-induced activation of JNK occurs through a stress-activated protein kinase/extracellular signal-regulated kinase kinase 1-independent mechanism. We conclude that activation of JNK and c-Abl by cisplatin is in part dependent upon the integrity of DNA mismatch repair function, suggesting that these kinases are part of the signal transduction pathway activated when mismatch repair proteins recognize cisplatin adducts in DNA.
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PMID:Differential induction of c-Jun NH2-terminal kinase and c-Abl kinase in DNA mismatch repair-proficient and -deficient cells exposed to cisplatin. 924 57

Bioflavonoid quercetin is known as an anti-cancer agent that induces apoptosis of tumor cells. Currently, however, little is understood about the effect of this drug on the function of normal cells. In this report, we address an unexpected, novel action of quercetin against apoptosis. Pretreatment with quercetin protected mesangial cells from hydrogen peroxide (H2O2)-induced apoptosis. A similar effect was observed in other cell types including LLC-PK1 epithelial cells and NRK49F fibroblasts. To explore the molecular mechanisms involved, we tested the effect of quercetin on c-Jun/activator protein-1 AP-1), the crucial mediator for H2O2-initiated apoptosis. Northern blot analysis revealed that quercetin suppressed the c-jun expression by H2O2. This was correlated with blunted activation of 12-O-tetradecanoylphorbol 13-acetate response element (TRE) in response to H2O2. These results suggested that quercetin inhibited apoptosis via intervention in the c-Jun/AP-1 pathway. To further investigate the action of quercetin, its effect on tyrosine kinases was studied. Immunoblot analysis revealed that H2O2 induced tyrosine phosphorylation. Quercetin inhibited this process in a dose-dependent manner. Inactivation of tyrosine kinases was an event upstream of c-Jun/AP-1, because tyrosine kinase inhibitors suppressed both activation of c-Jun/AP-1 and induction of apoptosis by H2O2. These findings elucidated the novel action of quercetin as an apoptosis inhibitor. This cytoprotective effect was found to be via suppression of the tyrosine kinase-c-Jun/AP-1 pathway triggered by oxidant stress.
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PMID:Unexpected protection of glomerular mesangial cells from oxidant-triggered apoptosis by bioflavonoid quercetin. 927 81

Prostaglandin H2 synthase (PGHS)-1 and PGHS-2 expression was examined in primary cultures of human amnion cells, an in vitro model of amnion tissue. Epidermal growth factor (EGF), the protein kinase C (PKC) activating phorbol ester TPA, and the protein phosphatase inhibitor, okadaic acid (OA), stimulated PGHS activity and the level of PGHS-2 mRNA, but did not affect the level of PGHS-1 mRNA. In situ hybridization suggested that the same population of cells responded to EGF, TPA and OA. Okadaic acid promoted PGHS activity independently of PKC. EGF stimulated the activity of extracellular signal-regulated protein kinase (Erk) and N-terminal c-Jun kinase (Jnk). OA increased Jnk activity but had no effect on Erk activity, while TPA had no influence on either Erk or Jnk activity. PD098059, a selective inhibitor of the Erk-activating kinase MEK, blocked the stimulation of PGHS expression by EGF, but did not decrease stimulation in response to OA. Herbimycin A, a tyrosine kinase inhibitor, suppressed the stimulation of PGHS activity and PGHS-2 mRNA abundance by all three stimulants, and blocked signalling via the Erk and Jnk mitogen-activated protein kinase pathways. Thus, growth factor stimulation, PKC activation and protein phosphatase inhibition induced the expression of PGHS-2 in primary amnion cells by distinct regulatory mechanisms involving tyrosine kinase(s). Tyrosine kinase inhibitors may constitute a new category of PGHS-2 inhibitors that act by blocking the expression of the enzyme.
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PMID:Regulation of prostaglandin H2 synthase-2 expression in primary human amnion cells by tyrosine kinase dependent mechanisms. 951 44

Collagenase-3 (MMP-13) is a matrix metalloproteinase (MMP) originally identified in breast carcinomas which is also produced at significant levels during fetal ossification and in arthritic processes. In this work, we have found that transforming growth factor beta1 (TGF-beta1), a growth factor widely assumed to be inhibitory for MMPs, strongly induces collagenase-3 expression in human KMST fibroblasts. In contrast, this growth factor down-regulated the expression in these cells of collagenase-1 (MMP-1), an enzyme highly related to collagenase-3 in terms of structure and enzymatic properties. The positive effect of TGF-beta1 on collagenase-3 expression was dose- and time-dependent, but independent of the effects of this growth factor on cell proliferation rate. Analysis of the signal transduction mechanisms underlying the up-regulating effect of TGF-beta1 on collagenase-3 expression demonstrated that this growth factor acts through a signaling pathway involving protein kinase C and tyrosine kinase activities. Functional analysis of the collagenase-3 gene promoter region revealed that the inductive effect of TGF-beta1 is partially mediated by an AP-1 site. Comparative analysis with the promoter region of the collagenase-1 gene which contains an AP-1 site at equivalent position, confirmed that TGF-beta1 did not have any effect on CAT activity levels of this promoter. Finally, by using electrophoretic mobility shift assays and antibody supershift analysis, we propose that c-Fos, c-Jun, and JunD may play major roles in the collagenase-3 activation by TGF-beta1 in human fibroblasts.
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PMID:Differential effects of transforming growth factor-beta on the expression of collagenase-1 and collagenase-3 in human fibroblasts. 954 14

We have previously shown that extracellular ATP caused cell death in PC12 cells through activation of its receptors. Oxidative stress has been implicated as a mechanism of cell death caused by extracellular ATP. In the present study we examined the possible signal transduction cascades leading to cell death by extracellular ATP. We found, using the electrophoretic mobility shift assay, that transcription factor AP-1 DNA binding activity was stimulated by extracellular ATP. Northern blot analysis showed that mRNA levels of c-fos, c-jun were elevated after treatment with ATP. The stimulation was receptor mediated, since it was blocked by the ATP receptor antagonist, suramin. The stimulated AP-1 binding was also blocked by the antioxidant N-acetyl-L-cysteine, indicating that reactive oxygen species generated following ATP stimulation were involved in the induction of AP-1 activity. It appears that both translational and posttranslational events contributed to the increased AP-1 DNA binding since cyclohexamide (a protein synthesis inhibitor), genistein (tyrosine kinase inhibitor) and staurosporine (PKC inhibitor) each partially blocked the AP-1 activation. Changes in AP-1 DNA binding activity may modulate expression of target genes involved in cell death pathways.
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PMID:Activation of transcription factor AP-1 by extracellular ATP in PC12 cells. 956 90

Treatment of renal mesangial cells with the vasoconstrictor angiotensin II stimulates a concentration-dependent increase in stress-activated protein kinase (SAPK) activity as measured by phosphorylation of the substrate c-Jun. Time course studies reveal a transient SAPK activation by angiotensin II which is maximal after 5-10 min of stimulation and rapidly declines thereafter to basal levels within 30 min. Using the highly selective angiotensin II AT1 receptor antagonist valsartan, a concentration-dependent inhibition of angiotensin II-induced SAPK activity is observed, clearly implying the AT1-receptor in this angiotensin II-mediated response. To further elucidate the mechanism involved in angiotensin II-induced SAPK activation, cells were treated with different inhibitors. Genistein, a tyrosine kinase inhibitor, greatly blocks (by 90%) the angiotensin II response, whereas pertussis toxin only partially inhibits angiotensin II-activated SAPK activity (by 76%). A highly potent protein kinase C inhibitor [3-[1-[3-(amidinothio)propyl-1H-indoyl-3-yl]-3-(1-methyl-1H- indoyl-3-yl) maleimide methane sulfonate], Ro 31-8220, as well as protein kinase C depletion from the cells by prolonged phorbol ester pretreatment, fail to inhibit the angiotensin II-induced SAPK activation. In summary these results suggest that angiotensin II AT1-receptor is able to activate the SAPK cascade in mesangial cells by a pathway independent of protein kinase C, but requiring both pertussis-toxin-sensitive and -insensitive G-proteins and tyrosine kinase activation.
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PMID:Angiotensin II stimulation of the stress-activated protein kinases in renal mesangial cells is mediated by the angiotensin AT1 receptor subtype. 957 Apr 79


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