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)

Stat3 is a latent transcription factor activated by various cytokines and growth factors. Phosphorylation on Tyr-705 is a prerequisite for dimer formation, nuclear translocation, binding to its cognate DNA sequences, and regulation of the target gene transcription. Ser-727 phosphorylation of Stat3 plays an additional role in the regulation of transcription. MEK kinase 1 (MEKK1) is a mitogen-activated protein kinase (MAPK) kinase kinase (MAPKKK) that activates the c-Jun NH(2)-terminal kinase signaling pathway. Here we report that MEKK1 is involved in the regulation of Stat3 activation by growth factors. Kinase-inactive MEKK1 inhibits Stat3 phosphorylation on tyrosine and serine, and its transcriptional activity stimulated by epidermal growth factor and platelet-derived growth factor in different cell types. In contrast, active MEKK1 induces Stat3 tyrosine and serine phosphorylation leading to a functionally active Stat3 capable of binding DNA and enhancing transcription. Ser-727 is phosphorylated by MEKK1 in vitro, whereas Tyr-705 phosphorylation induced by MEKK1 involves Src and Janus kinases in vivo. These data demonstrate for the first time a novel role of MEKK1 to modulate tyrosine kinases that results in the activation of specific members of STAT family.
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PMID:Regulation of Stat3 activation by MEK kinase 1. 1127 53

Endothelin-1 (ET-1) is a vasoconstrictor peptide known to be a potent mitogen for glomerular mesangial cells (GMC). In the current study, it is demonstrated that ET-1 treatment of GMC results in serine phosphorylation of the 66-kDa isoform of the adapter protein Shc (p66(Shc)). ET-1-induced serine phosphorylation of p66(Shc) requires activation of the mitogen-activated protein kinase (MAPK)/extracellular signal-regulated kinase (ERK) signaling module and is efficiently inhibited by both a MAPK/ERK kinase (MEK)-selective inhibitor and adenovirus-mediated transfer of a dominant interfering MEK1 mutant. Furthermore, adenovirus-mediated transfer of a constitutively active MEK1 mutant was found to markedly increase p66(Shc) serine phosphorylation. Adenoviruses encoding constitutively active mutants of MAPK kinases 3 and 6 (upstream kinases of p38(MAPK)) and 7 (upstream kinase of c-Jun NH(2)-terminal kinase) failed to induce serine phosphorylation of this adaptor protein. Serine phosphorylation of p66(Shc) resulted in its association with the serine binding motif-containing protein 14-3-3. ET-1-induced phosphorylation of a serine encompassed in the 14-3-3 binding motif of p66(Shc) was confirmed in experiments employing anti-phospho-14-3-3 binding motif antibodies. These studies are the first to demonstrate that G protein-coupled receptors stimulate serine phosphorylation of p66(Shc) and the first to report the formation of a signaling complex between p66(Shc) and 14-3-3.
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PMID:Endothelin-1 induces serine phosphorylation of the adaptor protein p66Shc and its association with 14-3-3 protein in glomerular mesangial cells. 1134 45

Transcriptional activation of eukaryotic genes often requires the cooperative action of many proteins. The interleukin 6 (IL-6) response element (IRE) is activated by signal transducer and activator of transcription 3 (STAT3), and stimulation with IL-6 leads to STAT3 tyr705 phosphorylation, dimerization, translocation to the nucleus and transactivation of target gene promoters containing IREs. Here, we report that IL-6 and 12-O-tetradecanoylphorbol-13-acetate (TPA) synergistically transactivate the IRE in HepG2 cells, which is coupled to a strong upregulation of c-Jun and c-Fos expression by TPA via the mitogen-activated protein kinase (MAPK) pathway. Overexpression of c-Jun and c-Fos strongly enhanced STAT3-driven IRE transactivation as well as transactivation of the human intercellular adhesion molecule (ICAM)-1 promoter. In contrast, c-Jun mutants lacking the transactivation domain, the DNA-binding domain, or mutants in which the serine residues 63 and 73 were replaced by alanine, did not cooperate with STAT3. In immunoprecipitation experiments, a direct association of STAT3 with c-Jun and c-Fos was observed in response to IL-6. Furthermore, c-Jun/STAT3 and c-Fos/STAT3 complexes were detected on IRE probes in electrophoretic mobility shift assay (EMSA) experiments, but did not bind nor transactivate the TPA response element (TRE). These results demonstrate that activator protein-1 (AP-1) transcription factors can cooperate with STAT3 in IRE transactivation in the absence of direct AP-1 DNA binding.
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PMID:c-Jun and c-Fos cooperate with STAT3 in IL-6-induced transactivation of the IL-6 respone element (IRE). 1135 8

Transforming growth factor (TGF)-beta plays a central role in fibrosis, contributing both to the influx and activation of inflammatory cells, as well as to activation of fibroblasts to elaborate extracellular matrix. In the past few years, new insight has been gained into signal transduction pathways downstream of the TGF-beta receptor serine-threonine kinases with the identification of a family of evolutionarily conserved Smad proteins. Two receptor-activated Smad proteins, Smad2 and Smad3, are phosphorylated by the activated TGF-beta type I receptor kinase, after which they partner with the common mediator, Smad4, and are translocated to the nucleus to where they participate in transcriptional complexes to control expression of target genes. We have shown in wound healing studies of mice null for Smad3, that loss of this key signaling intermediate interferes with the chemotaxis of inflammatory cells to TGF-beta as well as with their ability to autoinduce TGF-beta. Moreover, studies with mouse embryo fibroblasts null for Smad3 show that TGF-beta-dependent induction of c-Jun and c-Fos, important in induction of collagen as well as in autoinduction of TGF-beta, is mediated by Smad3. Based on these observations, we hypothesize that loss of Smad3 will confer resistance to fibrosis and result in reduced inflammatory cell infiltrates, reduced autoinduction of TGF-beta, important to sustain the process, and reduced elaboration of collagen. Preliminary observations in a model of radiation-induced fibrosis confirm this hypothesis and suggest that inhibitors of Smad3 might have clinical application both to improve wound healing and to reduce fibrosis.
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PMID:Is Smad3 a major player in signal transduction pathways leading to fibrogenesis? 1145 11

In response to DNA damage, p53 protein transiently stabilizes and accumulates in the nucleus, where it performs its role as a transcription factor. Phosphorylation of p53 increases its sequence-specific DNA-binding activity. In the present study, we have examined the effect of methylmethane sulfonate (MMS) to HCT-116 human colon cancer cells on the phosphorylation of p53. Results show that p53 protein becomes phosphorylated at serine 15 (Ser15) and Ser392 residues after treatment with MMS in a time-dependent manner. Increased levels of phospho-p53(Ser15) and phospho-p53(Ser392) were maintained up to 50 h of the MMS treatment. We also examined the involvement of probable kinase(s), which could be responsible for MMS-induced phosphorylation of p53 at Ser15 and Ser392. In vitro phosphorylation assay, carried out with the immunoprecipates of MMS-treated cells, showed an increased phosphorylation of p53 by c-Jun kinase 1 (JNK1) at early time points (2.5 h). However, with cyclin-dependent kinase (Cdk2) and TFIIH complex associated kinase CAK, the phosphorylation of p53 was increased at later time points (25 h). The phosphorylation of p53 by Cdc2 and MAPK (p38) kinases remained unaffected in the MMS-treated versus untreated cells. The MMS-induced phosphorylation of p53 correlates with our previous findings of p53's ability for increased sequence-specific DNA-binding and transcriptional activity in the cells treated with DNA alkylating agents.
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PMID:DNA alkylation-induced phosphorylation of p53 and activation of kinases in colon cancer cells. 1149 44

The molecular basis of X-linked lymphoproliferative (XLP) disease has been attributed to mutations in the signaling lymphocytic activation molecule-associated protein (SAP), an src homology 2 domain-containing intracellular signaling molecule known to interact with the lymphocyte-activating surface receptors signaling lymphocytic activation molecule and 2B4. To investigate the effect of SAP defects on TCR signal transduction, herpesvirus saimiri-immortalized CD4 Th cells from XLP patients and normal healthy individuals were examined for their response to TCR stimulation. CD4 T cells of XLP patients displayed elevated levels of tyrosine phosphorylation compared with CD4 T cells from healthy individuals. In addition, downstream serine/threonine kinases are constitutively active in CD4 T cells of XLP patients. In contrast, TCR-mediated activation of Akt, c-Jun-NH(2)-terminal kinases, and extracellular signal-regulated kinases in XLP CD4 T cells was transient and rapidly diminished when compared with that in control CD4 T cells. Consequently, XLP CD4 T cells exhibited severe defects in up-regulation of IL-2 and IFN-gamma cytokine production upon TCR stimulation and in MLRs. Finally, SAP specifically interacted with a 75-kDa tyrosine-phosphorylated protein upon TCR stimulation. These results demonstrate that CD4 T cells from XLP patients exhibit aberrant TCR signal transduction and that the defect in SAP function is likely responsible for this phenotype.
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PMID:Abnormal T cell receptor signal transduction of CD4 Th cells in X-linked lymphoproliferative syndrome. 1150 8

Phosphorylation of inositol 1,3,4-trisphosphate by inositol 1,3,4-trisphosphate 5/6-kinase is the first committed step in the formation of higher phosphorylated forms of inositol. We have shown that the eight proteins called the COP9 signalosome complex copurify with calf brain 5/6-kinase. Because the complex has been shown to phosphorylate c-Jun in vitro, we tested both the complex and 5/6-kinase and found that both are able to phosphorylate c-Jun and ATF-2 on serine/threonine residues. These findings establish a link between two major signal transduction systems: the inositol phosphates and the stress response system.
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PMID:Inositol 1,3,4-trisphosphate 5/6-kinase is a protein kinase that phosphorylates the transcription factors c-Jun and ATF-2. 1153 64

The c-Jun N-terminal protein kinase mitogen-activated protein kinases (JNK MAPKs) are an evolutionarily-conserved family of serine/threonine protein kinases. First identified in 1990 when intraperitoneal injection of the protein synthesis inhibitor cycloheximide activated a 54 kDa protein kinase, the JNK MAPKs have now taken on a prominent role in signal transduction. This research has revealed a number of levels of complexity. Alternative gene splicing is now recognised to result in ten different JNK MAPK isoforms of 46-55 kDa, and these isoforms differ in their substrate affinities. Furthermore, although originally classified as stress-activated protein kinases (SAPKs), or SAPKs, the JNK MAPKs are also critical mediators of signal transduction in response to stimulation by cytokines and some growth factors. JNK MAPKs have been shown to be critical mediators in dorsal closure in developing Drosophila embryos, and targeted knockout of murine JNK MAPKs has suggested a critical involvement of these kinases in mammalian embryonic development. Recent work has also highlighted their importance in programmed cell death. Thus, the JNK MAPKs may provide a critical target for regulation in both normal and diseased states.
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PMID:The c-Jun N-terminal protein kinase family of mitogen-activated protein kinases (JNK MAPKs). 1155 21

Mice lacking expression of the p66 isoform of the ShcA adaptor protein (p66(ShcA)) are less susceptible to oxidative stress and have an extended life span. Specifically, phosphorylation of p66(ShcA) at serine 36 is critical for the cell death response elicited by oxidative damage. We sought to identify the kinase(s) responsible for this phosphorylation. Utilizing the SH-SY5Y human neuroblastoma cell model, it is demonstrated that p66(ShcA) is phosphorylated on serine/threonine residues in response to UV irradiation. Both c-Jun N-terminal kinases (JNKs) and p38 mitogen-activated protein kinases are activated by UV irradiation, and we show that both are capable of phosphorylating serine 36 of p66(ShcA) in vitro. However, treatment of cells with a multiple lineage kinase inhibitor, CEP-1347, that blocks UV-induced JNK activation, but not p38, phosphatidylinositol 3-kinase, or MEK1 inhibitors, prevented p66(ShcA) phosphorylation in SH-SY5Y cells. Consistent with this finding, transfected activated JNK1, but not the kinase-dead JNK1, leads to phosphorylation of serine 36 of p66(ShcA) in Chinese hamster ovary cells. In conclusion, JNKs are the kinases that phosphorylate serine 36 of p66(ShcA) in response to UV irradiation in SH-SY5Y cells, and blocking p66(ShcA) phosphorylation by intervening in the JNK pathway may prevent cellular damage due to light-induced oxidative stress.
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PMID:c-Jun N-terminal kinase specifically phosphorylates p66ShcA at serine 36 in response to ultraviolet irradiation. 1160 89

The neuronal growth-associated protein SCG10 is enriched in the growth cones of neurons where it destabilizes microtubules and thus contributes to the dynamic assembly and disassembly of microtubules. Since its microtubule-destabilizing activity is regulated by phosphorylation, SCG10 may link extracellular signals to rearrangements of the neuronal cytoskeleton. To identify signal transduction pathways that may lead to SCG10 phosphorylation, we tested a series of serine-threonine-directed protein kinases that phosphorylate SCG10 in vitro. We demonstrate that purified SCG10 can be phosphorylated by two subclasses of mitogen-activated protein (MAP) kinases, c-Jun N-terminal/stress-activated protein kinase (JNK/SAPK) and p38 MAP kinase. Moreover, SCG10 was found to bind tightly and specifically to JNK3/SAPKbeta. JNK3/SAPKbeta phosphorylation occurs at Ser-62 and Ser-73, residues that result in reduced microtubule-destabilizing activity for SCG10. Endogenous SCG10 also undergoes increased phosphorylation in sympathetic neurons at times of JNK3/SAPKbeta activation following deprivation from nerve growth factor. Together these observations indicate that activation of JNK/SAPKs provides a pathway for phosphorylation of SCG10 and control of growth cone microtubule formation following neuronal exposure to cellular stresses.
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PMID:c-Jun N-terminal kinase-3 (JNK3)/stress-activated protein kinase-beta (SAPKbeta) binds and phosphorylates the neuronal microtubule regulator SCG10. 1171 27


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