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)

This paper describes the development of a robust, miniaturizable, and quantitative fluorescence-based assay for mitogen-activated protein kinase kinase 7 (MKK7). As a first step, the basic steady-state kinetics of the MKK7-catalyzed phosphorylation of c-Jun N-terminal kinases (JNKs) 1, 2, and 3 were defined using standard radiometric methods. Subsequently, the authors found that in addition to the holo JNKs, a series of novel small peptides (based on the region around the JNK phosphorylation site) are also substrates, provided that these were prephosphorylated on the Y residue of the TPY motif. One of these peptide substrates was used in the development of a fluorescence polarization-based assay using an antibody as a sensor. The assay was successfully miniaturized for use with conventional fluorescence polarization (FP) reader technology in 8.5 microl and on the single microl scale using Evotec proprietary 2-dimensional fluorescence intensity distribution analysis (2D-FIDA) anisotropy and liquid handling technology. The steady-state kinetic parameters derived using the FP or 2D-FIDA anisotropy format assays correlated well with those generated using a radiometric assay. Moreover, the quantitative sensitivity to known inhibitors was maintained independent of the format and assay volume. In addition, the authors found that the 2D-FIDA anisotropy assay exhibited superior performance statistics (typical Z' = approximately 0.5) relative to conventional FP (typical Z' = 0.3) and yielded the additional benefit of order-of-magnitude savings in terms of reagent costs. The 2D-FIDA anisotropy assay was used to carry out a successful high-throughput screening in 1-microl final volume against company file compounds.
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PMID:Development of a 1-microl scale assay for mitogen-activated kinase kinase 7 using 2-D fluorescence intensity distribution analysis anisotropy. 1459 57

Homeodomain-interacting protein kinase 2 (HIPK2) is a serine/threonine kinase involved in transcriptional regulation and apoptosis. Here we demonstrate that HIPK2 regulates transforming growth factor (TGF) beta-induced c-Jun NH(2)-terminal kinase (JNK) activation and apoptosis. HIPK2 colocalizes with Daxx, a protein acting in TGF-beta-induced JNK activation and apoptosis, in promyelocytic leukemia (PML) nuclear bodies, and triggers PML-nuclear body disruption and release of Daxx. HIPK2 interacts in vitro and in vivo via its kinase domain with Daxx, and a fraction of Daxx coprecipitates with HIPK2 under physiological conditions. Moreover, overexpression of HIPK2 leads to Daxx phosphorylation, and ectopic expression of HIPK2 activates the JNK signaling pathway, which is enhanced by coexpression of Daxx. HIPK2 signals to JNK via a pathway using Daxx and the mitogen-activated protein kinase kinases MKK4/SEK1 and MKK7. Ectopic expression of HIPK2 and Daxx potentiates TGF-beta-induced apoptosis in human p53-deficient hepatocellular carcinoma cells. Finally, we demonstrate that knockdown of endogenous HIPK2 using RNA interference inhibits TGF-beta-induced JNK activation and apoptosis. Taken together, our findings indicate that HIPK2 participates in the TGF-beta signaling pathway leading to JNK activation and apoptosis.
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PMID:HIPK2 regulates transforming growth factor-beta-induced c-Jun NH(2)-terminal kinase activation and apoptosis in human hepatoma cells. 1467 85

The mitogen-activated protein kinase (MAPK) c-Jun N-terminal kinase (JNK) is a critical regulator of collagenase-1 production in rheumatoid arthritis (RA). The MAPKs are regulated by upstream kinases, including MAPK kinases (MAPKKs) and MAPK kinase kinases (MAP3Ks). The present study was designed to evaluate the expression and regulation of the JNK pathway by MAP3K in arthritis. RT-PCR studies of MAP3K gene expression in RA and osteoarthritis synovial tissue demonstrated mitogen-activated protein kinase/ERK kinase kinase (MEKK) 1, MEKK2, apoptosis-signal regulating kinase-1, TGF-beta activated kinase 1 (TAK1) gene expression while only trace amounts of MEKK3, MEKK4, and MLK3 mRNA were detected. Western blot analysis demonstrated immunoreactive MEKK2, TAK1, and trace amounts of MEKK3 but not MEKK1 or apoptosis-signal regulating kinase-1. Analysis of MAP3K mRNA in cultured fibroblast-like synoviocytes (FLS) showed that all of the MAP3Ks examined were expressed. Western blot analysis of FLS demonstrated that MEKK1, MEKK2, and TAK1 were readily detectable and were subsequently the focus of functional studies. In vitro kinase assays using MEKK2 immunoprecipitates demonstrated that IL-1 increased MEKK2-mediated phosphorylation of the key MAPKKs that activate JNK (MAPK kinase (MKK)4 and MKK7). Furthermore, MEKK2 immunoprecipitates activated c-Jun in an IL-1 dependent manner and this activity was inhibited by the selective JNK inhibitor SP600125. Of interest, MEKK1 immunoprecipitates from IL-1-stimulated FLS appeared to activate c-Jun through the JNK pathway and TAK1 activation of c-Jun was dependent on JNK, ERK, and p38. These data indicate that MEKK2 is a potent activator of the JNK pathway in FLS and that signal complexes including MEKK2, MKK4, MKK7, and/or JNK are potential therapeutic targets in RA.
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PMID:Regulation of c-Jun N-terminal kinase by MEKK-2 and mitogen-activated protein kinase kinase kinases in rheumatoid arthritis. 1473 42

During the development of multicellular organisms, concerted actions of molecular signalling networks determine whether cells undergo proliferation, differentiation, death or ageing. Here we show that genetic inactivation of the stress signalling kinase, MKK7, a direct activator of JNKs in mice, results in embryonic lethality and impaired proliferation of hepatocytes. Beginning at passage 4-5, mkk7(-/-) mouse embryonic fibroblasts (MEFs) display impaired proliferation, premature senescence and G2/M cell cycle arrest. Similarly, loss of c-Jun or expression of a c-JunAA mutant in which the JNK phosphorylation sites were replaced with alanine results in a G2/M cell-cycle block. The G2/M cell-cycle kinase CDC2 was identified as a target for the MKK7-JNK-c-Jun pathway. These data show that the MKK7-JNK-c-Jun signalling pathway couples developmental and environmental cues to CDC2 expression, G2/M cell cycle progression and cellular senescence in fibroblasts.
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PMID:MKK7 couples stress signalling to G2/M cell-cycle progression and cellular senescence. 1503 80

Stress-activated protein kinase/c-Jun NH2-terminal kinase (SAPK/JNK), which belongs to the family of mitogen-activated protein kinase (MAPK), is activated by many types of cellular stress or extracellular signals. Recent studies, including the analysis with knockout cells and mice, have led towards understanding the molecular mechanism of stress-induced SAPK/JNK activation and the physiological roles of SAPK/JNK in embryonic development and immune responses. Two SAPK/JNK activators, SEK1 and MKK7, are required for full activation of SAPK/JNK, which responds to various stimuli in an all-or-none manner in mouse embryonic stem (ES) cells. SAPK/JNK activation plays essential roles in organogenesis during mouse development by regulating cell proliferation, survival or apoptosis and in immune responses by regulating cytokine gene expression. Furthermore, SAPK/JNK is involved in regulation of mRNA stabilization, cell migration, and cytoskeletal integrity. Thus, SAPK/JNK has a wide range of functions in mammalian cells.
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PMID:Activation mechanism and physiological roles of stress-activated protein kinase/c-Jun NH2-terminal kinase in mammalian cells. 1506 57

The c-Jun N-terminal kinase (JNK/SAPK) signaling cascade controls a spectrum of cellular processes, including cell growth, differentiation, transformation, and apoptosis. We recently demonstrated that stress kinase MKK7, a direct activator of JNKs, couples stress signaling to G2/M cell cycle progression, CDC2 expression, and cellular senescence. We further explored other molecules involved in JNK pathway and found that both MKK4, another direct activator of JNK, and c-Jun, a direct substrate of JNK, have similar roles to MKK7. Here we discuss the importance of the MKK4/MKK7-JNK-c-Jun pathway linking stress and developmental signals to cell proliferation, cell cycle progression, cellular senescence, and apoptosis including recent unpublished data from our lab.
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PMID:Stress kinase MKK7: savior of cell cycle arrest and cellular senescence. 1510 16

c-Jun NH(2)-terminal kinase (JNK), also known as stress-activated protein kinase (SAPK), is activated primarily by inflammatory cytokines and environmental stresses including toxic metal exposure. To reveal the upstream kinase responsible for JNK activation by toxic metals, the phosphorylation status and the activity of JNK were examined in mouse embryonic stem (ES) cells lacking MKK4 or MKK7 following exposure to CdCl(2) or HgCl(2). Treatment with CdCl(2) or HgCl(2) induced the phosphorylation of JNK in a dose- and time-dependent manner in wild-type ES cells. In both mkk4(-/-) and mkk7(-/-) ES cells, CdCl(2)- or HgCl(2)-induced phosphorylation and activation of JNK were suppressed significantly. However, in mkk7(-/-) ES cells treated with CdCl(2) and HgCl(2), JNK activation was not abolished (suppressed by 56% and 78%, respectively). These findings suggest that the full activation of JNK by toxic metal exposure requires both MKK4 and MKK7, and these upstream kinases might contribute differentially in JNK activation between mouse ES cells exposed to CdCl(2) and HgCl(2).
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PMID:Requirement of MKK4 and MKK7 for CdCl2- or HgCl2-induced activation of c-Jun NH2-terminal kinase in mouse embryonic stem cells. 1530 99

Activation of the cytoplasmic (Ras-Raf-MEK-ERK) signaling cascade was shown to be both, necessary and sufficient for transformation in vitro as well as in vivo. However, over the last years the involvement of stress-activated protein kinases (SAPKs)/Jun N-terminal kinases (JNKs), and their substrate c-Jun in the process of cellular transformation has been suggested. To dissect the mechanisms through which JNK signaling contributes to the transformation process we employed a recently generated constitutively active version of this kinase, SAPKbeta-MKK7, which behaves like a weakly transforming oncogene in vitro. Dissection of the transforming potential of oncogenic JNK demonstrates that it is sufficient for tumor induction in nude mice. In vitro studies and analysis of tumor material support the conclusion that oncogenic JNK primarily transforms through its effects on cell proliferation and tumor vascularization but does not affect cell survival.
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PMID:Tumor induction by activated JNK occurs through deregulation of cellular growth. 1537 40

CYLD is a tumor suppressor that is mutated in familial cylindromatosis, an autosomal dominant predisposition to multiple tumors of the skin appendages. Recent studies suggest that transfected CYLD has deubiquitinating enzyme activity and inhibits the activation of transcription factor NF-kappaB. However, the role of endogenous CYLD in regulating cell signaling remains poorly defined. Here we report a critical role for CYLD in negatively regulating the c-Jun NH(2)-terminal kinase (JNK). CYLD knockdown by RNA interference results in hyper-activation of JNK by diverse immune stimuli, including tumor necrosis factor-alpha, interleukin-1, lipopolysaccharide, and an agonistic anti-CD40 antibody. The JNK-inhibitory function of CYLD appears to be specific for immune receptors because the CYLD knockdown has no significant effect on stress-induced JNK activation. Consistently, CYLD negatively regulates the activation of MKK7, an upstream kinase known to mediate JNK activation by immune stimuli. We further demonstrate that CYLD also negatively regulates IkappaB kinase, although this function of CYLD is seen in a receptor-dependent manner. These findings identify the JNK signaling pathway as a major downstream target of CYLD and suggest a receptor-dependent role of CYLD in regulating the IkappaB kinase pathway.
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PMID:Negative regulation of JNK signaling by the tumor suppressor CYLD. 1549

Stress-activated protein kinase/c-Jun NH(2)-terminal kinase (SAPK/JNK) is activated by many types of cellular stresses and extracellular signals. Recent studies, including the analysis with knockout mice, have led to progress towards understanding the physiological roles of SAPK/JNK activation in embryonic development in addition to immune responses. SAPK/JNK activation plays essential roles in organogenesis during mouse development by regulating cell survival, apoptosis, and proliferation. Two SAPK/JNK activators, SEK1 and MKK7, are required for fetal liver formation and full activation of SAPK/JNK, which responds to various stimuli in an all-or-none manner. This article focuses on physiological roles of SAPK/JNK activation in fetal liver formation and in apoptosis regulation.
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PMID:Physiological roles of SAPK/JNK signaling pathway. 1549 81


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