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)

Cytokine modulation of elastin gene expression was examined by assay of elastin mRNA abundance and by transient transfections of cultured human skin fibroblasts and rat aortic smooth muscle cells with elastin promoter/reporter gene (chloramphenicol acetyltransferase, CAT) constructs. Incubation of cells with human recombinant tumor necrosis factor-alpha (TNF-alpha) markedly suppressed the elastin mRNA levels in a time- and dose-dependent manner by up to 91%. TNF-alpha also suppressed the expression of the elastin promoter/CAT construct by up to 70% in transiently transfected cells, indicating regulation at the transcriptional level. This suppression was temporally preceded by rapid and transient up-regulation of c-jun and c-fos genes. The down-regulatory effect of TNF-alpha on elastin promoter activity was abolished by co-transfections with a synthetic double-stranded AP-1 oligomer. Furthermore, co-transfection of the elastin promoter construct with c-jun and c-fos expression plasmids resulted in a marked decrease in the promoter activity. Elucidation of the cis-regulatory elements in the elastin promoter by 5' deletion construct analysis implicated a region -290 to -198 containing one AP-1 binding site. The functional role of this AP-1 site was further tested by gel retardation assays which indicated formation of a DNA-protein complex specific for TNF-alpha treated cells. This complex could be partially dissociated by a competing oligomer containing the consensus AP-1 binding site. These observations suggest that the inhibitory effects of TNF-alpha on elastin gene expression involve the transcription factor AP-1. Interferon-gamma also suppressed the elastin gene expression at the mRNA level by approximately 52%, but it had no effect on the elastin promoter activity, suggesting post-transcriptional mechanisms. These results indicate that mediators released from inflammatory cells can modulate elastin gene expression, and such modulation may play a role in diseases characterized by altered accumulation of elastic fibers in tissues.
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PMID:Tumor necrosis factor-alpha down-regulates human elastin gene expression. Evidence for the role of AP-1 in the suppression of promoter activity. 128 83

The cAMP-responsive element/activating transcription factor (CRE/ATF) element (also known as NF-ELAM1) of the endothelial leukocyte adhesion molecule-1 (ELAM-1) promoter is necessary for full cytokine responsiveness. It differs from a consensus cAMP-responsive element (CRE) by 1 nucleotide (G-->A conversion) and does not mediate transcriptional activation in response to cAMP. We reported previously that cAMP actually decreases ELAM-1 synthesis induced by tumor necrosis factor (TNF). We now show that cAMP decreases the ELAM-1 promoter response to TNF in transient transfection assays in bovine aortic endothelial cells and that cAMP-mediated inhibition maps to the CRE/ATF element. Electrophoretic mobility shift assays using the ELAM-1 CRE/ATF DNA sequence reveal three complexes. Antibody supershift assays suggest the slowest migrating form (complex 1) contains ATF2, the middle form (complex 2) contains ATF2 and c-Jun, and the fastest migrating form (complex 3) contains a CRE-binding protein. TNF increases c-Jun-containing complex 2 while diminishing complex 1, whereas cAMP decreases complex 2 and increases complex 1. Complex 3 is unchanged by either treatment, and the CRE-binding protein is not phosphorylated. Our data suggest that a change in the composition of the proteins binding to the CRE/ATF promoter element contributes to the competing effects of TNF and cAMP on ELAM-1 gene expression.
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PMID:cAMP and tumor necrosis factor competitively regulate transcriptional activation through and nuclear factor binding to the cAMP-responsive element/activating transcription factor element of the endothelial leukocyte adhesion molecule-1 (E-selectin) promoter. 751 52

The transactivating function of the c-Jun proto-oncogene component of the AP-1 transcription factor is acutely regulated by a wide variety of cellular signals via modulation of phosphorylation of two serines (63 and 73). The viral oncoprotein, v-Jun, while containing homologous serines, is not phosphorylated in cells. A novel family of stress-activated protein kinases (SAPKs), also termed Jun N-terminal domain kinases (JNKs), are responsible for mediating S63/73 phosphorylation in response to a variety of cellular stimuli including tumor necrosis factor-alpha, heat stress and u.v. light. The p54 alpha 1, alpha 2, p54 beta and p46 beta SAPKs are shown to bind directly to c-Jun but not to v-Jun, with an absolute requirement for c-Jun amino acids 31-47, a region deleted in v-Jun. Inactive SAPKs tightly bind c-Jun in resting cells and may be a manifestation of the 'delta' inhibitor, a previously described repressor of c-Jun function.
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PMID:Stress-activated protein kinases bind directly to the delta domain of c-Jun in resting cells: implications for repression of c-Jun function. 789 27

JNK protein kinases are distantly related to mitogen-activated protein kinases (ERKs) and are activated by dual phosphorylation on Tyr and Thr. The JNK protein kinase group includes the 46-kDa isoform JNK1. Here we describe the molecular cloning of a second member of the JNK group, the 55-kDa protein kinase JNK2. The activities of both JNK isoforms are markedly increased by exposure of cells to UV radiation. Furthermore, JNK protein kinase activation is observed in cells treated with tumor necrosis factor. Although both JNK isoforms phosphorylate the NH2-terminal activation domain of the transcription factor c-Jun, the activity of JNK2 was approximately 10-fold greater than that of JNK1. This difference in c-Jun phosphorylation correlates with increased binding of c-Jun to JNK2 compared with JNK1. The distinct in vitro biochemical properties of these JNK isoforms suggest that they may have different functions in vivo. Evidence in favor of this hypothesis was obtained from the observation that JNK1, but not JNK2, complements a defect in the expression of the mitogen-activated protein kinase HOG1 in the yeast Saccharomyces cerevisiae. Together, these data indicate a role for the JNK group of protein kinases in the signal transduction pathway initiated by proinflammatory cytokines and UV radiation.
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PMID:Signal transduction by tumor necrosis factor mediated by JNK protein kinases. 796 72

During an acute phase response following inflammatory stimuli, specific changes occur in the synthesis and secretion of many hepatic proteins. Because the expression of differentiated function requires the coordinated regulation of many genes, we investigated the activity of general and tissue-specific transcription factors using a rat liver model of the acute phase response induced by Freund's adjuvant. Nuclear extracts and RNAs were prepared throughout a 48-h posttreatment period. Mobility shift assays revealed increased binding activity by nuclear factor-kappa B, interleukin-6 (IL-6) responsive element binding protein, and activating protein 1 (AP-1). Two AP-1 complexes were induced during the acute phase response, and correlation between their presence and transcription activity was demonstrated by transfection studies. Elevated binding activity of AP-1 also correlated with elevated levels of c-jun, junD, junB, and c-fos mRNAs. Western blots showed elevated hepatic levels of c-Jun but not c-Fos proteins during the acute phase response. In addition, IL-6, tumor necrosis factor-alpha, and IL-1 beta, cytokine regulators of the acute phase response, stimulated expression of an AP-1 responsive reporter gene introduced by DNA-mediated transfection into adult rat hepatocytes in primary culture. These findings demonstrate the complexity of AP-1 hepatic transcription factor responses to humoral regulators with direct hepatocellular effects.
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PMID:Activation of activating protein 1 during hepatic acute phase response. 843 Aug 10

The c-Jun N-terminal kinases (JNK) are activated by various stimuli, including UV light, interleukin-1, tumor necrosis factor-alpha (TNF-alpha), and CD28 costimulation. Induction of JNK by TNF-alpha, a strong apoptosis inducer, implies a possible role of JNK in the regulation of programmed cell death. Present studies show that lethal doses of gamma radiation (GR) induced JNK activities at the early phase of apoptosis in Jurkat T-cells. We demonstrate that JNK1 was activated by either the T-cell activation signals, anti-CD28 monoclonal antibody plus phorbol 12-myristate 13-acetate (PMA), or the apoptosis-inducing treatment, GR; however, the induction patterns were different. In contrast to the rapid and transient JNK1 activation caused by CD28 signaling plus PMA, GR induced a delayed and persistent JNK1 activation. This implies a distinct regulatory mechanism and specific function of JNK1 in irradiated cells. The nuclear and cytosolic JNK1 activities were simultaneously increased in the irradiated cells without an evident change in the protein levels. The abilities of GR to induce JNK1 activation and DNA fragmentation were correlated. Peripheral blood lymphocytes were more sensitive to GR than Jurkat cells in JNK1 induction. The responsiveness of JNK1 to GR suggests the involvement of JNK1 in the initiation of the apoptosis process.
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PMID:Persistent activation of c-Jun N-terminal kinase 1 (JNK1) in gamma radiation-induced apoptosis. 855 65

The Rel family of transcription factors are important mediators of various cytokine stimuli such as interleukin (IL)-1, tumor necrosis factor (TNF)-alpha, and CD28 costimulation in T cell effector responses. These stimuli induce Rel family DNA-binding activity to the kappaB enhancer and CD28 response elements of many cytokine gene promoters leading to cytokine production. Consistent with the importance of Rel family induction during immune responses, c-Rel knockout mice exhibit profound defects in T cell functions including IL-2 secretion and T cell proliferative responses to CD28 plus T cell receptor costimulation. The novel protein kinases, c-Jun NH2-terminal kinases (JNKs)/stress-activated protein kinases, are also activated by TNF-alpha, IL-1, and CD28 costimulation. Because of the common regulation of c-Rel and JNK1 by these agents in T cells, we investigated the role of JNK1 in c-Rel activation. We found that MAP kinase kinase kinase (MEKK) 1, a JNK1 activator, induced transcription from the human immunodeficiency virus-1 long terminal repeat and IL-2R alpha promoters in a kappaB-dependent manner. Coexpression of IkappaBalpha, a c-Rel inhibitor, inhibited the MEKK1-induced transcriptional activity. JNK1 synergized with MEKK1 in activating transcription from a kappaB-driven heterologous promoter. Furthermore, JNK1 associated with c-Rel in vivo in Jurkat T cells by coimmunoprecipitation assays and bound directly to c-Rel in a yeast two-hybrid assay. c-Rel also competed with c-Jun in in vitro kinase assays. However, JNK1 did not phosphorylate c-Rel, NF-kappaB, and IkappaB alpha in vitro, indicating that c-Rel may serve as a docking molecule to allow JNK1 phosphorylation of certain Rel-associated proteins. Transactivation of the IL-2Ralpha and HIV-kappaB-driven promoters by c-Rel was augmented by coexpression of MEKK1. These results demonstrate the first significant role for the MEKK1 kinase cascade module in c-Rel-mediated transcription.
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PMID:Interaction between c-Rel and the mitogen-activated protein kinase kinase kinase 1 signaling cascade in mediating kappaB enhancer activation. 862 42

Aggregation of the high-affinity Fc receptors for immunoglobulin E (IgE) (FcepsilonRI) on the surface of mast cells initiates intracellular signal transduction pathways including the tyrosine phosphorylation of cellular proteins, phosphoinositide hydrolysis, an increase in intracellular calcium, and protein kinase C activation. These signals are believed to be involved in the exocytic release of inflammatory mediators such as vasoactive amines, cytokines, and lipid metabolites. However, the downstream consequences of these early activation events are not well defined. One exception is the activation of the extracellular signal-regulated kinases/mitogen-activated protein kinases. One member of the mitogen-activated protein kinase superfamily, designated c-Jun amino-terminal kinase (JNK), has been recently identified. JNK is activated following dual phosphorylation at a Thr-Pro-Tyr motif in response to diverse stimuli including tumor necrosis factor-alpha, heat shock, or ultraviolet irradiation. We found that JNK was strongly activated by antigen cross-linking in a mouse mast cell line passively sensitized with ovalbumin-specific IgE. Anti-mouse IgE antibody also activated JNK. MEK kinase 1 (MEKK1) which activates the JNK activator, JNK kinase (JNKK), was similarly activated by antigen stimulation. JNK but not p42(erk2) activation induced by antigen was significantly inhibited in the presence of wortmannin, a known inhibitor of phosphatidylinositol 3-kinase. These results indicate that in response to the aggregation of FcepsilonRI on mast cells, phosphatidylinositol 3-kinase activation is involved in the stimulation of the MEKK1, JNKK, JNK pathway.
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PMID:Aggregation of the FcepsilonRI on mast cells stimulates c-Jun amino-terminal kinase activity. A response inhibited by wortmannin. 866 3

Mitogen-activated protein (MAP) kinases are a multigene family activated by many extracellular stimuli. There are three groups of MAP kinases based on their dual phosphorylation motifs, TEY, TPY, and TGY, which are termed extracellular signal-regulated protein kinases (ERK1/2), c-Jun N-terminal kinases, and p38, respectively. A new MAP kinase family member termed Big MAP kinase 1 (BMK1) or ERK5 was recently cloned. BMK1 has a TEY sequence similar to ERK1/2 but has unique COOH-terminal and loop-12 domains. To define BMK1 regulation, its activation in cultured rat vascular smooth muscle cells was characterized. Angiotensin II, phorbol ester, platelet-derived growth factor, and tumor necrosis factor-alpha were the strongest stimuli for ERK1/2 but were weak activators of BMK1. In contrast, H2O2 caused concentration-dependent activation of BMK1 but not ERK1/2. Sorbitol activated both BMK1 and ERK1/2. BMK1 activation by H2O2 was calcium-dependent and appeared ubiquitous as shown by stimulation in human skin fibroblasts, human vascular smooth muscle cells, and human umbilical vein endothelial cells. These findings demonstrate that activation of BMK1 is different from ERK1/2 and suggest an important role for BMK1 as a redox-sensitive kinase.
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PMID:Big mitogen-activated protein kinase 1 (BMK1) is a redox-sensitive kinase. 866 94

We have reported previously that activation of human umbilical vein endothelial cells (HUVECs) through CD40, using a recombinant soluble form of trimerized CD40 ligand, leads to induction of E-selectin, vascular cell adhesion molecule-1 (VCAM-1), and intercellular adhesion molecule-1 (ICAM-1). Here, we compare the effects of CD40 ligand with those of tumor necrosis factor (TNF) and interleukin 1 (IL-1). All three ligands induce transient increases in E-selectin (peak 4 h) and VCAM-1 (peak 8-24 h), as well as sustained increases in ICAM-1 (plateau 24 h). Quantitatively, TNF is more potent than IL-1, which is much more potent than CD40 ligand. The same hierarchy is observed for transcriptional activation of an E-selectin promoter reporter gene construct in transiently transfected HUVECs. TNF and CD40 ligand each induced activation of the transcription factors NF-kappa B, IRF-1, and ATF-2/c-Jun, measured by electrophoretic mobility shift assays, but this response appeared quantitatively similar. All three agents transiently (peak 30 min) activated Jun NH2-terminal kinase (JNK), which has been implicated in transcription of E-selectin through its actions on ATF-2/c-Jun. Activation of JNK again showed a hierarchy of potency (TNF > IL-1 >> CD40 ligand), although the time course of induction was similar for all three agents. After 44 h of pretreatment, TNF, IL-1, and CD40 ligand each display homologous desensitization for reinduction of surface expression of E-selectin. A similar pattern of homologous desensitization for reactivation of JNK was observed. We conclude that TNF, IL-1, and CD40 ligand all activate similar responses in ECs, and that homologous desensitization of JNK may explain the inability of individual cytokines to reinduce E-selectin expression.
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PMID:Activation and homologous desensitization of human endothelial cells by CD40 ligand, tumor necrosis factor, and interleukin 1. 869 Nov 31


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