Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:2.7.11.13 (protein kinase C)
 49,245 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The CEF-4/9E3 cytokine gene is expressed aberrantly in chicken embryo fibroblasts (CEF) transformed by the Rous sarcoma virus. The expression of CEF-4 is dependent on both transcriptional and post-transcriptional mechanisms of regulation. The characterization of the promoter region indicated that three distinct regulatory elements corresponding to an AP-1 binding site (or TRE), a PRDII/kappaB domain, and a CAAT box are involved in the activation by pp60(v-)src. In this report we investigate the signaling pathways controlling the expression of the TRE and PRDII domain. The expression of a dominant negative mutant of p21(ras) reduced the activity of both elements. In contrast a similar mutant of c-Raf-1 affected modestly the activation dependent on the TRE but not PRDII. The stress-activated protein kinase (SAPK)/Jun N-terminal kinase (JNK) pathway was important for the activity of PRDII and the TRE but was not markedly stimulated by pp60(v-)src. The addition of calphostin C and the inhibition of protein kinase C (PKC) diminished the accumulation of the CEF-4 mRNA and reduced the activity of a TRE-controlled promoter. Likewise, the depletion of PKC by chronic treatment with phorbol esters inhibited the activation of the TRE. Rous sarcoma virus-transformed CEF treated with calphostin C were also flatter, did not display a high degree of criss-crossing, and appeared morphologically normal. Hence PKC was important for the activation of AP-1 and the morphological transformation of CEF. The constitutive expression of CEF-4 was correlated with transformation only when dependent on the TRE. This was not true for PRDII, which was the only element required for the constitutive activation to the CEF-4 promoter in nontransformed cells treated chronically with phorbol esters.
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PMID:Multiple signaling pathways control the activation of the CEF-4/9E3 cytokine gene by pp60v-src. 879 20

Experiments were designed to clarify the role of c-Jun/c-Fos and of putative phorbol 12-myristate-13-acetate-(PMA)-responsive elements (TREs) in the induction of plasminogen-activator inhibitor 1 (PAI-1) gene transcription in the human hepatoma cell line HepG2 by activators of protein kinase C (PKC). Treatment of HepG2 cells with the phorbol ester PMA or serum rapidly and transiently increased c-Jun and c-Fos mRNA and protein levels prior to PAI-1 induction. This induction of PAI-1 gene transcription was found to be dependent on ongoing protein synthesis. An essential role of c-Jun and c-Fos in basal and PMA-stimulated transcription of the PAI-1 gene is demonstrated by our finding that antisense c-jun and c-fos oligodeoxynucleotides both strongly reduced basal and PMA-stimulated PAI-1 synthesis. Since it has already been shown that two TREs between positions -58 and -50 and between -79 and -72 of the PAI-1 promoter are essential for basal and PMA-induced PAI-1 promoter activity ([16]), we examined binding of nuclear proteins to these elements. The protein-binding activity to the TRE between positions -79 and -72 shows very strong PMA induction of an unknown factor, which is not related to c-Jun or c-Fos. The TRE binding between positions -58 and -50 forms two complexes, both containing c-Jun protein. The faster migrating complex primarily contains c-Jun homodimers. The amount of the faster migrating complex is enhanced more than 30-fold in PMA-treated cells, due to a strongly increased binding of c-Jun homodimers and, to a minor extent, to binding of c-Jun/c-Fos heterodimers. Dissociation experiments suggest that the c-Jun/c-Fos heterodimers bind with much lower affinity compared to binding of c-Jun homodimers. Together with the finding that both antisense c-jun and antisense c-fos oligodeoxynucleotides reduced the amount of c-Jun homodimer, we conclude that binding of c-Jun homodimer to the TRE at positions -58 to -50 is important in the basal activity and PMA activation of the PAI-1 promoter in HepG2 cells.
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PMID:Role of c-Jun and proximal phorbol 12-myristate-13-acetate-(PMA)-responsive elements in the regulation of basal and PMA-stimulated plasminogen-activator inhibitor-1 gene expression in HepG2. 891 35

1,25-Dihydroxyvitamin D3 (calcitriol) at 100 nmol/l elicited morphological differentiation and expression of collagen IV in mouse F9 embryonal carcinoma cells, and its effect was enhanced and accelerated by dibutyryl-cAMP (db-cAMP). The RAR beta 2 promoter was also activated, as evidenced by an increase in beta-galactosidase activity in an F9 reporter cell line with a stably integrated RAR beta 2-lacZ construct. All three effects were slower and less extensive with calcitriol than with retinoic acid, even in the presence of db-cAMP. Activation of the RAR beta 2 promoter by calcitriol required its TRE sequence, whereas db-cAMP required the CRE. TPA also activated the RAR beta 2 promoter, requiring a functional TRE. Thus, in the RAR beta 2 promoter the TRE sequence, whose function has so far been unidentified, mediates the effects of calcitriol and TPA. RAR beta 2 promoter activation by calcitriol was blocked by inhibitors of protein kinase C indicating that calcitriol elicits its effect via protein kinase C. Therefore, calcitriol induces differentiation of F9 mouse embryonal carcinoma cells at least in part by a pathway different from the classical one operative with retinoic acids.
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PMID:Induction of mouse embryonal carcinoma cell differentiation and activation of the retinoic acid receptor beta 2 promoter by 1,25-dihydroxyvitamin D3. 896 Mar 71

Tissue-type plasminogen activator (t-PA) gene expression in human endothelial cells and HeLa cells is stimulated by the protein kinase C activator phorbol 12-myristate 13-acetate (PMA) at the level of transcription. To study the mechanism of transcriptional regulation, we have characterized a segment of the t-PA gene extending from -135 to +100 by in vivo footprinting analysis [dimethyl sulphate (DMS) method] and gel mobility shift assay. In vivo footprinting analysis revealed changes in cleavage pattern in five distinct promoter elements in both endothelial cells and HeLa cells, including a PMA-responsive element (TRE), a CTF/NF-1 binding site and three GC-boxes, and an altered cleavage pattern of the TRE and CTF/NF-1 element after PMA treatment of HeLa cells. Although endothelial cells and HeLa cells differed in the exact G residues protected by nuclear proteins,in vitro bandshift analysis showed that nuclear protein binding to the t-PA promoter was qualitatively and quantitatively very similar in both cell types, except for the TRE. Protein binding to the TRE under non- stimulated conditions was much higher in human endothelial cells than in HeLa cells, and this TRE-bound protein showed a lower dissociation rate in the endothelial cells than in HeLa cells. In endothelial cells, the proteins bound to the TRE consisted mainly of the AP-1 family members JunD and Fra-2, while in HeLa cells predominantly JunD, FosB and Fra-2 were bound. The proteins bound to the other protected promoter elements were identified as SP-1 (GC-box II and III) and CTF/NF-1 (CTF/NF-1 binding site). After PMA treatment of the cells, AP-1 and SP-1 binding was increased two-fold in endothelial cell nuclear extracts and >20-fold in HeLa nuclear extracts. In the endothelial cells, all Jun and Fos forms (c-Jun, JunB, JunD, c-Fos, FosB, Fra-1 and Fra-2) were part of the AP-1 complex after PMA induction. In HeLa cells, the complex consisted predominantly of c-Jun and the Fos family members FosB and Fra-2. In the light of previous studies involving mutational analysis of the human and murine t-PA promoter our results underline an important role of the five identified promoter regions in basal and PMA-stimulated t-PA gene expression in intact human endothelial cells and HeLa cells. The small differences in DMS protection pattern and differences in the individual AP-1 components bound in endothelial cells and HeLa cells point to subtle cell-type specific differences in t-PA gene regulation.
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PMID:Cell-type specific DNA-protein interactions at the tissue-type plasminogen activator promoter in human endothelial and HeLa cells in vivo and in vitro. 901 59

Activating protein-1 (AP-1) binding phorbol ester responsive elements (TRE) are located downstream of the transcription initiation site in the U5 region of the human immunodeficiency virus type-1 (HIV-1) long terminal repeat (LTR). These downstream sequence elements, termed DSE, can bind cFos and junD and transmit protein kinase C (PKC) activation signals to the LTR. Further studies suggested the DSE might also bind AP-1-related proteins of the CREB/ATF family. Since enhanced HIV-1 expression is associated with activation of the cAMP-dependent protein kinase A (PKA) signaling pathway, we determined whether binding of CREB/ATF proteins to the DSE mediate cAMP/PKA activation of the HIV-1 LTR. In the present study. DSE binding complexes in nuclear protein extracta from colonic epithelial cells are shown to contain ATF-1, ATF-2, and CREB and transfection of either an ATF-2 or PKA expressing plasmid transactivated the DSE. Cholera toxin (Ctx), a potent activator of the cAMP/PKA pathway. Increased HIV-1 virus production from a latently infected promonocytic cell line, U1. Ctx increased LTR promoter activity and increased the CREB content of DSE binding complexes. Transfection of U1 cells with a series of mutant LTR reporter constructs demonstrated that the Ctx response was in large part mediated by the DSE. The Ctx response was also mediated by a heterologous promoter containing multiple TRE sites. Nuclear protein extracts from a T-cell line infected by HIV-1 contained higher levels of CREB/ATF proteins and manifested increased CREB/ATF binding activity. Collectively, these results indicate the DSE are TRE-like cAMP responsive elements that bind both AP-1 and CREB/ATF permitting induction of the HIV-1 LTR by both PKC and PKA activation signals.
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PMID:U5 region of the human immunodeficiency virus type 1 long terminal repeat contains TRE-like cAMP-responsive elements that bind both AP-1 and CREB/ATF proteins. 920 Dec 33

In this study, the regulatory elements involved in ICAM-1 transcriptional response to phorbol ester (12-0-tetradecanoylphorbol-13-acetate; TPA) have been investigated in the human neuroblastoma cell line, SK-N-SH. TPA induced intercellular adhesion molecule 1 (ICAM-1) protein expression in SK-N-SH cells within 24 h of treatment as judged by indirect immunofluorescence. Basal ICAM-1 mRNA levels were barely detectable in untreated SK-N-SH cells but were induced by TPA to a maximal level with 4 h and were reduced thereafter. Analysis of the 5' promoter sequence of ICAM-1 revealed two regions that functioned equally in the TPA induction of ICAM-1 transcription. The first region (-145 to -227) contained a nuclear factor-kappa B (NF kappa B) element. The second region (-316 to -390) contained a putative TPA-responsive element (TRE; TGATTCA) and a TATA box. Deletion and point mutation of the latter region indicated that the TRE was indeed the functional element within this region and acted fully and independently of all other elements including the TATA box at position -352. This TRE bound TPA induced specific nuclear complexes in vitro containing junD, c-jun, c-fos, and fra2 but not cAMP-responsive element binding/activating transcription factor family proteins. ICAM-TRE binding activity was induced within 30 min following TPA treatment. This preceded the appearance of ICAM-NF kappa B site binding activity. Cotransfection of c-jun and c-fos expression vectors into SK-N-SH cells induced transactivation from ICAM-1 promoter constructs containing the intact but not mutated TRE site. Primer extension analyses revealed that TPA had induced transcription exclusively at two sites -40 and -41 bp upstream of the translation start site. These data show that the ICAM-TRE and its cognate jun- and fos-containing transcription factors play a predominant role in the transcriptional response of ICAM-1 to the protein kinase C activator TPA in SK-N-SH cells.
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PMID:Transcriptional regulation of intercellular adhesion molecule 1 by phorbol ester in human neuroblastoma cell line SK-N-SH involves jun- and fos-containing activator protein 1 site binding complex(es). 921 73

The human histone H3.3B gene belongs to the group of replacement histone genes, which are up-regulated during differentiation of cells. Here we provide evidence that a cAMP response element/PMA response element (CRE/TRE) located in the proximal promoter contributes to the expression of the H3.3B gene. (1) Band shift and supershift analysis demonstrated the binding of AP-1 and transcription factors of the CRE-binding protein/activating-transcription-factor family to the H3.3B CRE/TRE. (2) Treatment of HeLa cells with PMA led to a 4-fold increase in H3. 3B mRNA levels within 2 h, whereas transcription of the cell cycle-dependent H3 histone genes remained constant. In contrast with PMA, cAMP did not affect H3.3B transcription. (3) PMA treatment of cells transiently transfected with H3.3B promoter constructs linked to a luciferase gene caused a 4-5-fold increase in reporter gene activity, whereas mutation of the CRE/TRE element abolished the PMA response. These results demonstrate that activation of the protein kinase C pathway by PMA results in an early up-regulation of H3.3B gene expression via the CRE/TRE element. Furthermore treatment with PMA apparently leads to differential induction of H3 histone subtype genes and this in turn can result in a remodelling of chromatin structure of cells before or during differentiation processes.
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PMID:cAMP/phorbol ester response element is involved in transcriptional regulation of the human replacement histone gene H3.3B. 944 89

Connexin (Cx) 26, a major gap junction protein expressed in mammary epithelial cells, has been considered to be a tumor suppressor gene candidate. This study investigated the molecular mechanism of transcriptional up-regulation of Cx26 by phorbol ester (TPA) in human immortalized MCF-10 mammary epithelial cells and MDA-MB-231 mammary cancer cells. Such up-regulation was mediated through the protein kinase C pathway and could be blocked by the PKC inhibitor, calphostin C. Based on the results of the nuclear run-on assay, there was a TPA-induced increase in the rate of transcriptional initiation. We identified a TPA-induced DNase I hypersensitivity (DH) region approximately 1 kb 5' upstream of the ATG translation starting site. Sequence analysis revealed that this DH region was located in intron 1 and contained two TRE-like TGAT/ATCA elements, two 5'TTCA3' motifs and a 5'AGGAAG3' PEA3 motif. Both TRE-like elements were capable of binding AP1. TPA inducibility of this DH region was seen by the CAT reporter assay and appeared to be direction-dependent suggesting a functional cooperation between PEA3/TTCA and TRE.
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PMID:Gap junction Cx26 gene modulation by phorbol esters in benign and malignant human mammary cells. 952 50

RRR-alpha-Tocopherol, but not RRR-beta-tocopherol, negative regulates proliferation of vascular smooth muscle cells at physiological concentrations. At the same concentrations RRR-alpha-tocopherol inhibits protein kinase C activity, whereas RRR-beta-tocopherol is ineffective. Furthermore, RRR-beta-tocopherol prevents the inhibition of cell growth and of protein kinase C activity caused by RRR-alpha-tocopherol. The negative regulation by RRR-alpha-tocopherol of protein kinase C activity appears to be the cause of smooth muscle cell growth inhibition. RRR-alpha-Tocopherol does not act by binding to protein kinase C directly but presumably by preventing protein kinase C activation. A second RRR-alpha-tocopherol effect has been found at the level of AP 1, the latter becoming activated by RRR-alpha-tocopherol under condition of protein kinase C inhibition or down regulation. AP-1 inhibition by RRR-alpha-tocopherol is seen, however, under condition of protein kinase C stimulation. Compositional changes of AP-1 have been found to be at the basis of the RRR-alpha-tocopherol effects. RRR-beta-tocopherol, provided with similar antioxidant properties, not only it does not affect AP 1 but it prevents the effects of RRR-alpha-tocopherol. Moreover, it has been observed that RRR-alpha-tocopherol is able to affect TRE regulated gene transcription. It is concluded that RRR-alpha-tocopherol acts specifically in vascular smooth muscle cells, by controlling a signal transduction pathway leading to cell proliferation by a non-antioxidant mechanism.
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PMID:RRR-alpha-tocopherol regulation of gene transcription in response to the cell oxidant status. 955 25

This article will firstly briefly review the newer generation of immunosuppressant drugs, focusing mainly on tacrolimus (FK-506), sirolimus (rapamycin), mycophenolate mofetil (RS-61443) and leflunomide (HWA 486) and then describe work carried out at the Lilly Research Centre on analogues of leflunomide and subsequent diversion into a structurally distinct series of compounds, the naphthopyrans. A clear structure activity relationship exists within this series and selected data from a Concanavalin A stimulated T-cell proliferation assay are presented to illustrate this. Although the compounds proved to possess little in vivo activity in our rheumatoid arthritis program, examination of the compounds in in vitro and in vivo models within the diabetic complications group showed the compounds behaved as would be anticipated for inhibitors of protein kinase C, although this direct mode of action was clearly not correct. Mechanistic investigations revealed that the favoured compound 290181 blocks phorbol 12,13-dibutyrate-induced binding of transcription factor proteins to the PEA3/TRE sequence of the promoter region of the urokinase plasminogen activator gene. The compounds also showed antiproliferative effects on vascular smooth muscle cells, an in vitro activity that translated into in vivo efficacy in a rat model of restenosis. Mechanistic studies here demonstrated that 290181 blocks proliferation in the G2/M phase of the cell cycle by binding directly to a novel site on tubulin. Finally the compounds were shown to inhibit the release of neutral proteases from interleukin-1 stimulated articular chondrocytes, this activity having implications in the degenerative aspects of osteoarthritis.
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PMID:Antiproliferative naphthopyrans: biological activity, mechanistic studies and therapeutic potential. 956 1


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