Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:1.14.14.3 (luciferase)
 38,195 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The kinases and regulatory proteins that convey signals initiated by transforming growth factor-beta (TGF-beta) to the nucleus are poorly characterized. To study the role of the extracellular signal-regulated kinase (ERK) pathway in this process, we transiently transfected NIH 3T3 fibroblasts with TGF-beta-responsive luciferase reporter genes and expression vectors designed to interrupt this kinase cascade. Mitogen-activated protein (MAP) kinase phosphatase-1 and a dominant negative MAP/ERK kinase 1 mutant reduced stimulation of plasminogen activator inhibitor-1 (PAI-1) promoter activity by TGF-beta1 from 11.5- to 4-fold and 4.9-fold, respectively. Similar results were observed with the type I collagen promoters. TGF-beta1 increased ERK1 activity 4.5-fold at 5 min and 3. 1-fold at 3 h, while Jun kinase and p38 activity were not affected. Cotransfection of a dominant negative mutant of the small G protein, Rac, but not dominant negative Ras, Cdc42, or Rho mutants, reduced the effects of TGF-beta1 on the PAI-1 promoter by approximately half. In support of a role for Rac in signaling by TGF-beta, GTP binding to Rac was increased 3.7-fold following exposure of NIH 3T3 cells to TGF-beta1 for 3 min. These findings indicate that TGF-beta1 modulates gene expression partly through ERK and Rac in NIH 3T3 cells.
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PMID:Extracellular signal-regulated kinase and the small GTP-binding protein, Rac, contribute to the effects of transforming growth factor-beta1 on gene expression. 866 31

G protein-coupled receptor agonists initiate a cascade of signaling events in neonatal rat ventricular myocytes that culminates in changes in gene expression and cell growth characteristic of hypertrophy. These responses have been previously shown to be dependent on Gq and Ras. Rho, a member of the Ras superfamily of GTPases, regulates cytoskeletal rearrangement and transcriptional activation of the c-fos serum response element. Immunofluorescence staining of cardiomyocytes shows that Rho is present and predominantly cytosolic. We used two inhibitors of Rho function, dominant negative N19RhoA and Clostridium botulinum C3 transferase, to examine the possible requirement for Rho in alpha1-adrenergic receptor-mediated hypertrophy. Both inhibitors markedly attenuated atrial natriuretic factor (ANF) reporter gene expression induced by alpha1-adrenergic receptor stimulation with phenylephrine, and virtually abolished the increase in ANF reporter gene expression induced by GTPase-deficient Galphaq. These effects were reproduced with the myosin light chain-2 reporter gene. Notably, N19RhoA did not block the ability of activated Ras to induce ANF and myosin light chain-2 reporter gene expression. Furthermore, activation of the extracellular signal-regulated kinase by phenylephrine was not blocked by N19RhoA, nor was it stimulated by an activated mutant of RhoA. Since activated RhoA and Ras produce a large synergistic effect on ANF-luciferase gene expression, we conclude that Rho functions in a pathway separate from but complementary to Ras. Our results provide direct evidence that Rho is an effector of Galphaq signaling and suggest for the first time that a low molecular weight GTPase other than Ras is involved in regulating myocardial cell growth and gene expression in response to heterotrimeric G protein-linked receptor activation.
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PMID:Rho is required for Galphaq and alpha1-adrenergic receptor signaling in cardiomyocytes. Dissociation of Ras and Rho pathways. 894 Jan 18

The molecular bases of the versatile functions of Rho-like GTPases are still unknown. Using luciferase assays with rat 3Y1 cells, we found that Rac1 is integrated downstream of Ras in the TRE (TPA response element) activation pathway. Coexpression of a mutant of p65PAK, PAK/RD, lacking the kinase domain but containing the Cdc42/Rac interactive binding (CRIB) region, suppressed the TRE activation and cell transformation caused by constitutively activated forms of Ras (RasV12) and Rac1 (Rac1V12). PAK/RD is a good tool to investigate the signaling pathways in which Rac and Cdc42 are involved.
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PMID:A domain containing the Cdc42/Rac interactive binding (CRIB) region of p65PAK inhibits transcriptional activation and cell transformation mediated by the Ras-Rac pathway. 911 69

The oncogenic proteins encoded by papovaviruses, the tumor antigens, have been extensively used as model systems to study mitogenic signaling and cell transformation. These proteins stimulate cell growth in cultured cells and induce tumors in virus infected or transgenic animals. One of these proteins, polyomavirus middle-T, acts like a constitutively activated tyrosine growth factor receptor. Middle-T recruits several cellular enzymes into a multifunctional complex located at cellular membranes. This results in the activation of cellular enzymes involved in the regulation of cell signaling, like tyrosine kinases of the Src family, a phosphatidylinositol 3-kinase and a GDP/GTP exchange factor for Ras. These activities are all required for stimulation of cell growth by middle-T and activate members of the MAP kinase family. Here we investigate the role of T antigen-activated pathways in the stimulation of transcription of immediate early genes. These genes are essential for progression of resting cells into S phase. Our data show that Rho family GTPases play an essential role in cell transformation by middle-T. Furthermore, we demonstrate that the c-fos promoter is activated by two Ras-initiated signaling cascades. One is Raf-dependent and requires binding of SHC and PI 3-kinase to the middle-T complex. This pathway signals via ternary complex factor (TCF) to the serum response element (SRE) of the c-fos promoter. Signaling to TCF by Raf also depends on functional Rac, but not CDC42, as demonstrated in luciferase reporter assays with an ETS domain-containing promoter. The second pathway is Raf-independent, does not require SHC but functional PI 3-kinase, and transduces signals via Rac to serum response factor (SRF). Microinjection of dominant negative Rac1 blocks nuclear translocation of ERK1 in middle-T-expressing cells. This lends support to the idea that the two signaling cascades initiated by Ras show crosstalk at the level of MAP kinase-mediated signaling to nuclear transcription factors.
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PMID:A role for the small GTPase Rac in polyomavirus middle-T antigen-mediated activation of the serum response element and in cell transformation. 912 74

Interstitial collagenases participate in the remodeling of skeletal matrix and are regulated by fibroblast growth factor (FGF). A 0.2-kb fragment of the proximal human interstitial collagenase [matrix metalloproteinase (MMP1)] promoter conveys 4- to 8-fold induction of a luciferase reporter in response to FGF2 in MC3T3-E1 osteoblasts. By 5'-deletion, this response maps to nucleotides -100 to -50 relative to the transcription initiation site. The 63- bp MMP1 promoter fragment -123 to -61 confers this FGF2 response on the rous sarcoma virus minimal promoter. Intact Ets and AP1 cognates in this element are both required for responsiveness. The AP1 site supports basal and FGF-inducible promoter activity. The intact Ets cognate represses basal transcriptional activity in both heterologous and native promoter contexts and is also required for FGF activation. FGF2 up-regulates a DNA-binding activity that recognizes the MMP1 AP1 cognate and contains immunoreactive Fra1 and c-Jun. Both constitutive and FGF-inducible DNA-binding activities are present in MC3T3-E1 cells that recognize the MMP1 Ets cognate; prototypic Ets transcriptional activators are not present in these complexes. Inhibitors of protein kinase C, phosphatidyl inositol 3-OH kinase, and calmodulin-dependent protein kinase do not attenuate MMP1 promoter activation. FGF2 activates ERK1/ERK2 signaling in osteoblasts; however, 25 microM MAPK-ERK kinase (MEK) inhibitor PD98059 (inhibits by > 85% the phosphorylation of ERK1/ERK2) has no effect on MMP1 promoter activation by FGF2. Ligand-activated and constitutively active FGF receptors initiate MMP1 induction. Dominant negative Ras abrogates MMP1 induction by constitutively active FGFR2-ROS, but dominant negative Rho and Rac do not inhibit induction. The mitogen-activated protein kinase (MAPK) phosphatase MKP2 [inactivates extracellular regulated kinase (ERK) = Jun N-terminal kinase (JNK) > p38 MAPK] completely abrogates MMP1 activation, whereas PAC1 (inactivates ERK = p38 > JNK) attenuates but does not completely prevent induction. Thus, a Ras- and MKP2-regulated MAPK pathway, independent of ERK1/ERK2 MAPK activity, mediates FGF2 transcriptional activation of MMP1 in MC3T3-E1 osteoblasts, converging upon the bipartite Ets-AP1 element. The DNA-protein interactions and signal cascades mediating FGF induction of the MMP1 promoter are distinct from two other recently described FGF response elements: the MMP1 promoter (-123 to -61) represents a third FGF-activated transcriptional unit.
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PMID:Fibroblast growth factor receptor signaling activates the human interstitial collagenase promoter via the bipartite Ets-AP1 element. 921 60

Rac, one member of Rho family GTPases, stimulates c-fos serum response element (SRE)-luciferase reporter gene in Rat-2 fibroblast cells. By transient transfection analysis, we demonstrated that the activation of phospholipase A2 (PLA2) and the subsequent production of arachidonic acid (AA) are essential for Rac-induced c-fos SRE activation, implying a critical role for PLA2 in the Rac-signalling pathway to the nucleus. Either pretreatment with mepacrine, a specific inhibitor of PLA2, or co-transfection with the expression plasmid of lipocortin-1, a proposed inhibitory protein of PLA2, selectively abolished RacV12-induced SRE activation. Further, we demonstrated that subsequent metabolism of AA, a major product of Rac-activated PLA2, by lipoxygenase (LO) is essential for Rac-induced c-fos SRE activation. In agreement with the role of the PLA2-AA-LO cascade as a potential mediator of Rac signalling to the nucleus, the addition of exogenous AA stimulated c-fos SRE-luciferase activity in an LO-dependent manner. Together, our results demonstrate that 'Rac-activated PLA2 and subsequent AA metabolism by LO' constitute a novel and specific pathway in Rac GTPase-induced c-fos SRE activation.
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PMID:Nuclear signalling by rac GTPase: essential role of phospholipase A2. 929 Nov 1

Rho regulates various cell functions, including cell morphology and motility. However, the functional role of Rho on the signaling pathway in myocardial cells (MCs) is unknown. In the present study, we attempted to explore the mode of Rho action for c-fos gene expression in MCs. Expression of the c-fos promoter/enhancer linked to the luciferase reporter gene (c-fos luciferase) was stimulated by the wild type of RhoA and the point-mutated active form of RhoA (RhoA Val14) but not the biologically inactive effector domain mutant of RhoA. Rho GDP dissociation inhibitor inhibited the action of RhoA on c-fos luciferase expression. The deletion analysis revealed that the c-fos serum response element (SRE) and the 12-O-tetradecanoylphorbol-13-acetate response element (TRE) mainly account for c-fos luciferase expression by RhoA Val14. The c-fos SRE mutant, which contains an intact binding site for the serum response factor but lacks the ternary complex factor binding site, was activated by RhoA Val14. The action of RhoA Val14 on c-fos luciferase expression was not inhibited by downregulation of protein kinase C, protein kinase C inhibitors, or tyrosine kinase inhibitors. These results indicate that activated RhoA stimulates c-fos gene expression through the c-fos SRE and TRE and that the signaling pathway from activated RhoA to the c-fos promoter/enhancer is independent of these inhibitor-sensitive pathways in MCs.
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PMID:Activated RhoA stimulates c-fos gene expression in myocardial cells. 935 40

We previously observed that the trophic actions of gastrin (G17) on the AR42J rat acinar cell line are mediated by mitogen-activated protein kinase (MAPK)-induced c-fos gene transcription via protein kinase C (PKC)-dependent and -independent pathways. In this study, we further investigated the signaling pathways that target c-fos in response to G17. G17 led to a sixfold induction in luciferase activity in cells transfected with plasmids containing the -356+109 sequence of the murine c-fos promoter, which includes the Sis-inducible element (SIE), serum response element (SRE), and the Ca2+/cAMP response element (CRE) regulatory elements. Addition of either the selective PKC inhibitor GF-109203X or the MAPK/extracellular signal-regulated kinase inhibitor PD-98059 resulted in an 80% reduction in luciferase activity. G17 induced the transcriptional activity of both Elk-1 and Sap-1a, transcription factors that bind to the E26 transformation specific (Ets) DNA sequence of the SRE, and this effect was inhibited by both GF-109203X and PD-98059. Point mutations in the Ets sequence led to a 4-fold induction of c-fos transcription stimulated by G17 and to a 1.3-fold induction in response to epidermal growth factor (EGF). In contrast, mutations in the CA rich G (CArG) sequence of the SRE prevented transcriptional activation by both G17 and EGF. G17 induction of the Ets mutant construct was unaffected by either GF-109203X or PD-98059. Because activation of the SRE involves the small GTP-binding protein Rho A, we examined the role of Rho A in G17 induction of c-fos transcription. Inactivation of Rho A by either the specific inhibitor C3 or by expression of a dominant negative Rho A gene inhibited G17 induction of both the wild-type and the Ets mutant constructs by 60%. C3 also inhibited G17-stimulated AR42J cell proliferation. Thus G17 targets the c-fos promoter CArG sequence via Rho A-dependent pathways, and Rho A appears to play an important role in the regulation of the trophic action of G17.
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PMID:Gastrin induces c-fos gene transcription via multiple signaling pathways. 995 Aug 15

Several extracellular stimuli mediated by G protein-coupled receptors activate c-fos promoter. Recently, we and other groups have demonstrated that signals from G protein-coupled receptors stimulate mitogen-activated protein kinases (MAPKs), extracellular signal-regulated kinase (ERK), c-Jun N-terminal kinase (JNK), and p38 MAPK. The activation of these three MAPKs is mediated in part by the G protein betagamma subunit (Gbetagamma). In this study, we characterized the signals from Gbetagamma to c-fos promoter using transient transfection of c-fos luciferase into human embryonal kidney 293 cells. Activation of m2 muscarinic acetylcholine receptor and overexpression of Gbetagamma, but not constitutively active Galphai2, stimulated c-fos promoter activity. The c-fos promoter activation by m2 receptor and Gbetagamma was inhibited by beta-adrenergic receptor kinase C-terminal peptide (betaARKct), which functions as a Gbetagamma antagonist. MEK1 inhibitor PD98059 and kinase-deficient mutant of JNK kinase, but not p38 MAPK inhibitor SB203580, attenuated the m2 receptor- and Gbetagamma-induced c-fos promoter activation. Activated mutants of Ras and Rho stimulated the c-fos promoter activity, and the dominant negative mutants of Ras and Rho inhibited the c-fos promoter activation by m2 receptor and Gbetagamma. Moreover, c-fos promoter activation by m2 receptor, Gbetagamma, and active Rho, but not active Ras, was inhibited by botulinum C3 toxin. These data indicated that both Ras- and Rho-dependent signaling pathways are essential for c-fos promoter activation mediated by Gbetagamma.
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PMID:Activation of c-fos promoter by Gbetagamma-mediated signaling: involvement of Rho and c-Jun N-terminal kinase. 1005 39

The transforming growth factor (TGF)-beta signal-transduction cascade from the cell membrane to the nuclear target is poorly characterised. Here we report that treatment with TGF-beta1 induces the levels of endogenous c-fos mRNA in Rat-2 fibroblast cells. In addition, by transient transfection analysis, TGF-beta1 was shown to stimulate c-fos serum response element (SRE)-driven reporter gene activity in a dose- and time-dependent manner, suggesting that SRE is one of the nuclear targets of TGF-beta1. To understand the signalling cascade by which TGF-beta1 mediates the transactivation of c-fos SRE, cells were either pre-treated with various inhibitors or co-transfected with expression plasmids encoding inhibitory proteins for Rho GTPase together with the SRE-luciferase reporter gene. Our results showed that an inhibition of protein kinase C (PKC) or RhoA selectively repressed the stimulation of c-fos SRE by TGF-beta1, implying the possible roles of PKC and RhoA GTPase in TGF-beta1-induced signalling to c-fos SRE.
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PMID:Involvement of protein kinase C and rho GTPase in the nuclear signalling pathway by transforming growth factor-beta1 in rat-2 fibroblast cells. 1020 47


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