Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:2.7.11.24 (mitogen-activated protein kinase)
 95,810 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

In bivalve molluscs, cell-mediated immunity is carried out by circulating hemocytes, resembling the monocyte/macrophage lineage of vertebrates, that can kill the microbes through phagocytosis and various cytotoxic reactions. Previous data demonstrated that activation of MAPKs (Mitogen Activated Protein Kinases) is involved in the response of mussel hemocytes (Mytilus galloprovincialis Lam.) to bacterial challenge. In this work, the possibility that modulation of components of tyrosine kinase-mediated cell signalling may participate in the activation of mussel hemocytes was investigated. Cell pre-treatment with the macrophage activator IFN gamma significantly increased the bactericidal activity of mussel hemocytes towards E. coli. Human recombinant IFN gamma stimulated tyrosine phosphorylation of different members of STAT-like proteins (Signal Transducers and Activators of Transcription), as evaluated by Western blotting of hemocyte protein extracts with specific anti-phospho-STAT antibodies. A similar increase in phosphorylation of immunoreactive STATs was observed in hemocytes incubated with E. coli, this indicating that tyrosine phosphorylation of STAT-like members represents a physiological step in hemocyte activation. IFN gamma lead to persistent phosphorylation of immunoreactive STAT1, a transcription factor that plays a critical role in innate immunity towards Gram negative bacteria in mammalian systems; moreover, hemocyte pretreatment with IFN gamma significantly increased bacteria-induced STAT1 phosphorylation, whereas IFN alpha did not. IFN gamma also transiently affected the phosphorylation state of different MAPKs. The extent and time course of MAPK phosphorylation induced by IFN gamma were distinct from those elicited by either IFN alpha or bacterial challenge. Overall, the results indicate that the hemocyte function can be modulated by heterologous cytokines and bacterial signals that act in concert through tyrosine kinase-mediated transduction pathways converging on STAT- and MAPK-like members.
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PMID:Tyrosine kinase-mediated cell signalling in the activation of Mytilus hemocytes: possible role of STAT-like proteins. 1472 Apr 63

The replication of hepatitis B virus (HBV) in hepatocytes is strongly inhibited in response to IFN-alpha/beta and IFN-gamma. Although it has been previously demonstrated that IFN-alpha/beta eliminates HBV RNA-containing capsids from the cell in a proteasome-dependent manner, the precise cellular pathway that mediates this antiviral effect has not been identified. Because IFN-induced signal transduction involves kinase-mediated activation of gene expression, we used an immortalized hepatocyte cell line that replicates HBV in an IFN-sensitive manner to investigate the role of cellular kinase activity and the cellular transcription and translation machinery in the antiviral effect. Our results indicate that Janus kinase activity is required for the antiviral effect of IFN against HBV, but that phosphatidylinositol 3-kinase, cyclin-dependent kinase, mitogen-activated protein kinase, and NF-kappaB activity are not. Additionally, we found that inhibitors of cellular transcription and translation completely abolish the antiviral effect, which also appears to require cellular kinase activity downstream of signal transduction and gene expression. Collectively, these results identify IFN-regulated pathways that interrupt the HBV replication cycle by eliminating viral RNA-containing capsids from the cell, and they provide direction for discovery of the terminal effector molecules that ultimately mediate this antiviral effect.
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PMID:Signal transduction pathways that inhibit hepatitis B virus replication. 1475 13

It has been widely shown that many plant-derived compounds present significant anti-inflammatory effects. For this reason, they represent potential molecules for the development of new drugs, especially designed for the treatment and/or control of chronic inflammatory states such as rheumatism, asthma, inflammatory bowel diseases, atherosclerosis, etc. This review focuses on the naturally-occurring compounds with anti-inflammatory properties and attempts to correlate their actions with the modulation of cytokines and associated intracellular signalling pathways; it continues the review published in the November, 2003 issue of Planta Medica. Abbreviations. AP-1:activator protein-1 CCR1:chemokine receptor 1 CINC-1:cytokine-induced neutrophil chemoattractant 1 COX:cyclooxygenase EGCG:(-)-epigallocatechin gallate ELAM-1:endothelial-leukocyte adhesion molecule-1 ERK:extracellular signal-regulated kinase GRO:growth-related oncogene HUVEC:human umbilical vein endothelial cells ICAM-1:intercellular adhesion molecule-1 IFN:interferon IL:interleukin iNOS:inducible nitric oxide synthase IRA:the natural interleukin receptor activation JAK:janus kinase JNK:c-Jun NH2-terminal kinase LPS:lipopolysaccharide MAPK:mitogen-activated protein kinases MCP:monocyte chemotactic protein MHC:major histocompatibility complex MIP:macrophage inflammatory protein MMP:matrix metalloproteinases MPO:myeloperoxidase NF-kappaBnuclear factor kappa B NO:nitric oxide PAF:platelet aggregation factor PGEE:prostaglandin PK:protein kinase PMA/TPA:phorbol myristate acetate RANTES:regulated upon activation normal T-cell expressed and secreted TGF-beta:transforming growth factor-beta TNFalpha:tumour necrosis factor VCAM-1:vascular cell adhesion molecule-1
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PMID:Anti-inflammatory compounds of plant origin. Part II. modulation of pro-inflammatory cytokines, chemokines and adhesion molecules. 1499 84

LPS binding to Toll-like receptor 4 induces a large number of genes through activation of NF-kappaB and IFN-regulatory factor-3 (IRF-3). However, no previous reports have tested the role of serum proteins in LPS-induced gene expression profiles. To investigate how serum proteins affect LPS-induced signaling, we investigated LPS-inducible genes in PBMC using an oligonucleotide probe-array system. Approximately 120 genes up-regulated by LPS were hierarchically divided into two clusters. Induction of one cluster, containing only IFN-inducible genes, was serum dependent. Real-time PCR analysis confirmed that IFN-inducible genes were induced only in the presence of serum, whereas inflammatory genes were induced both in the presence and absence of serum. Further analysis demonstrated that addition of LPS-binding protein (LBP), but not of soluble CD14 to the serum-free medium enabled the induction of IFN-inducible genes and IFN-beta itself by LPS in human monocytes. The mRNAs for IFN-beta and IFN-inducible genes were induced by LPS only in the presence of serum from LBP(+/+) mice, and not in the presence of serum from LBP(-/-) mice. Blocking experiments also confirmed the involvement of LBP in this phenomenon. Immunoblotting analysis showed that phosphorylation of c-Jun N-terminal kinase, p38, IRF-3, tyrosine kinase 2, and STAT1 by LPS, but not of NF-kappaB and extracellular signal-regulated kinase was abrogated in the absence of LBP. This critical role for LBP implies the presence of possible mechanisms linking LBP to the intracellular signaling between Toll-like receptor 4 and IRF-3, leading to the induction of IFN-beta by LPS.
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PMID:Lipopolysaccharide-binding protein critically regulates lipopolysaccharide-induced IFN-beta signaling pathway in human monocytes. 1512 6

Protein kinase C-theta (PKC-theta) plays important roles in the activation and survival of lymphocytes and is the predominant PKC isoform expressed in T-cells. Interferons regulate T-cell function and activation, but the precise signaling mechanisms by which they mediate such effects have not been elucidated. We determined whether PKC-theta is engaged in interferon (INF) signaling in T-cells. Both Type I (alpha, beta) and Type II (gamma) IFNs induced phosphorylation of PKC-theta in human T-cell lines and primary human T-lymphocytes. Such phosphorylation of PKC-theta resulted in activation of its kinase domain, suggesting that this kinase plays a functional role in interferon signaling. Consistent with this, inhibition of PKC-theta protein expression using small interfering RNAs (siRNA) abrogated IFN-alpha- and IFN-gamma-dependent gene transcription via GAS elements. Similarly, blocking of PKC-theta kinase activity by overexpression of a dominant-negative PKC-theta mutant also blocked GAS-driven transcription, further demonstrating a requirement for PKC-theta in IFN-dependent transcriptional activation. The effects of PKC-theta on IFN-dependent gene transcription were not mediated by regulation of the IFN-activated STAT pathway, as siRNA-mediated PKC-theta knockdown had no effects on STAT1 phosphorylation and binding of STAT1-containing complexes to SIE/GAS elements. On the other hand, siRNA-mediated PKC-theta inhibition blocked phosphorylation/activation of MKK4, suggesting that interferon-dependent PKC-theta activation regulates downstream engagement of MAP kinase pathways. Altogether, these findings demonstrate that PKC-theta is an interferon-inducible kinase and strongly suggest that it plays an important role in the generation of interferon-responses in T-cells.
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PMID:Engagement of protein kinase C-theta in interferon signaling in T-cells. 1515 Feb 72

Expression of interferon-tau gene (IFNT) by conceptuses of cattle and sheep must be in phase with the physiological state of the mother if the pregnancy is to be successful. IFNT has a close-to-consensus AP1 site (-71 to -64), overlapping a binding site for Ets-2 (-79 to -70), the key transcription factor controlling IFNT expression. When a bovine IFNT gene control region-luciferase (luc) construct was transfected into mouse 3T3 fibroblasts in the presence of Ets-2 and oncogenic Ras, luc expression was activated (50- to 100-fold). Mutations in either the activator protein 1 (AP1) site or the Ets-2 site of this construct abolished this effect. Similarly, a mutation of Thr72 of the Ets-2 or the addition of a specific inhibitor for the MAPK signal transduction pathway also markedly reduced expression. IFNT promoter activity was up-regulated in response to colony-stimulating factor-1 in 3T3 cells expressing the colony-stimulating factor-1 receptor c-fms. This response did not occur when the AP1 site or the Ets-2 binding sites were mutated. Nor was the response observed in 3T3 cells expressing an inactive form of c-fms. The experiments indicate that IFNT can be activated by growth factors operating through the Ras/MAPK pathway. The Ets-2 and AP1 binding sites are essential for such effects. The AP1 site, however, is noncanonical and unable to bind either cJun or cFos. These data emphasize the importance of a complex Ets-2 enhancer for expression of IFNT and suggest a means whereby the mother can exert control over conceptus IFN-tau production.
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PMID:Regulation of interferon-tau (IFN-tau) gene promoters by growth factors that target the Ets-2 composite enhancer: a possible model for maternal control of IFN-tau production by the conceptus during early pregnancy. 1521 85

We studied the role of 15-deoxy-delta (12,14)-PGJ2 (15d-PGJ2), a macrophage inhibitor with reported therapeutic effects on experimental allergic encephalomyelitis, in human astrocyte activation in vitro. 15d-PGJ2 inhibited a broad range of astrocyte inflammatory gene expression induced by IL-1, including cytokines (TNFalpha and IL-6), chemokines (RANTES/CCL5 and IP-10/CXCL10) and inducible nitric oxide synthase. 15d-PGJ2 inhibited transactivation of NF-kappaB-dependent promoters, as well as p38 and JNK MAPK phosphorylation induced by IL-1, while having no inhibitory effect on IFN-induced Stat signaling pathways. Our results demonstrating 15d-PGJ2-mediated astrocyte deactivation through inhibition of NF-kappaB are similar to those described for macrophages, and add astrocytes as additional targets for this prostaglandin (PG).
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PMID:15-deoxy-delta (12,14)-PGJ2 inhibits astrocyte IL-1 signaling: inhibition of NF-kappaB and MAP kinase pathways and suppression of cytokine and chemokine expression. 1526 71

Regulation of cytokine and chemokine expression in microglia may have implications for CNS inflammatory disorders. In this study we examined the role of the cyclopentenone PG 15-deoxy-Delta(12,14)-PGJ(2) (15d-PGJ(2)) in microglial inflammatory activation in primary cultures of human fetal microglia. 15d-PGJ(2) potently inhibited the expression of microglial cytokines (IL-1, TNF-alpha, and IL-6). We found that 15d-PGJ(2) had differential effects on the expression of two alpha-chemokines; whereas the Glu-Lys-Arg (ELR)(-) chemokine IFN-inducible protein-10/CXCL10 was inhibited, the ELR(+) chemokine IL-8/CXCL8 was not inhibited. These findings were shown in primary human microglia and the human monocytic cells line THP-1 cells, using diverse cell stimuli such as bacterial endotoxin, proinflammatory cytokines (IL-1 and TNF-alpha), IFN-beta, and HIV-1. Furthermore, IL-8/CXCL8 expression was induced by 15d-PGJ(2) alone or in combination with TNF-alpha or HIV-1. Combined results from EMSA, Western blot analysis, and immunocytochemistry showed that 15d-PGJ(2) inhibited NF-kappaB, Stat1, and p38 MAPK activation in microglia. Adenoviral transduction of super-repressor IkappaBalpha, dominant negative MKK6, and dominant negative Ras demonstrated that NF-kappaB and p38 MAPK were involved in LPS-induced IFN-inducible protein 10/CXCL10 production. Interestingly, although LPS-induced IL-8/CXCL8 was dependent on NF-kappaB, the baseline or 15d-PGJ(2)-mediated IL-8/CXCL8 production was NF-kappaB independent. Our results demonstrate that 15d-PGJ(2) has opposing effects on the expression of two alpha-chemokines. These data may have implications for CNS inflammatory diseases.
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PMID:15-deoxy-Delta12,14-prostaglandin J2 inhibits IFN-inducible protein 10/CXC chemokine ligand 10 expression in human microglia: mechanisms and implications. 1532 15

During early pregnancy in ruminants, a type I interferon (IFN-tau) signals from the conceptus to the mother to ensure the functional survival of the corpus luteum. IFN-tau operates through binding to the type I IFN receptor (IFNR). Here we have explored the possibility that IFNAR2, one of the two subunits of the receptor, might interact with hitherto unknown signal transduction factors in the uterus that link IFN action to pathways other than the well established Janus kinase-signal transducer and activator of transcription pathways. A yeast two-hybrid screen of an ovine (ov) endometrial cDNA library with the carboxyl-terminal 185 amino acids of ovIFNAR2 as bait identified stress-activated protein kinase-interacting protein 1 (ovSin1) as a protein that bound constitutively through its own carboxyl terminus to the receptor. ovSin1 is a little studied, 522-amino acid-long polypeptide (molecular weight, 59,200) that is highly conserved across vertebrates, but has identifiable orthologs in Drosophila and yeast. It appears to be expressed ubiquitously in mammals, although in low abundance, in a wide range of mammalian tissues in addition to endometrium. Sin1 mRNA occurs in at least two alternatively spliced forms, the smaller of which lacks a 108-bp internal exon. ovSin1, although not exhibiting features of a membrane-spanning protein, such as IFNAR2, is concentrated predominantly in luminal and glandular epithelial cells of the uterine endometrium. When ovSin1 and ovIFNAR2 are coexpressed, the two proteins can be coimmunoprecipitated and colocalized to the plasma membrane and to perinuclear structures. Sin1 provides a possible link among type I IFN action, stress-activated signaling pathways, and control of prostaglandin production.
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PMID:Interaction of stress-activated protein kinase-interacting protein-1 with the interferon receptor subunit IFNAR2 in uterine endometrium. 1534 82

Adaptive cellular immunity is required to clear HSV-1 infection in the periphery. Myeloid dendritic cells (DCs) are the first professional Ag-presenting cell to encounter the virus after primary and secondary infection and thus the consequences of their infection are important in understanding the pathogenesis of the disease and the response to the virus. Following HSV-1 infection, both uninfected and infected human DCs acquire a more mature phenotype. In this study, we demonstrate that type I IFN secreted from myeloid DC mediates bystander activation of the uninfected DCs. Furthermore, we confirm that this IFN primes DCs for elevated IL-12 p40 and p70 secretion. However, secretion of IFN is not responsible for the acquisition of a mature phenotype by HSV-1-infected DC. Rather, virus binding to a receptor on the cell surface induces DC maturation directly, through activation of the NF-kappaB and p38 MAPK pathways. The binding of HSV glycoprotein D is critical to the acquisition of a mature phenotype and type I IFN secretion. The data therefore demonstrate that DCs can respond to HSV exposure directly through recognition of viral envelope structures. In the context of natural HSV infection, the coupling of viral entry to the activation of DC signaling pathways is likely to be counterbalanced by viral disruption of DC maturation. However, the parallel release of type I IFN may result in paracrine activation so that the DCs are nonetheless able to mount an adaptive immune response.
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PMID:Herpes simplex virus type-1-induced activation of myeloid dendritic cells: the roles of virus cell interaction and paracrine type I IFN secretion. 1535 61


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