Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:2.7.11.1 (protein kinase)
 81,284 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

2,3,7,8-Tetrachloro-p-dioxin (TCDD) induced a modest stimulation of nuclear protein phosphorylation in explant tissue cultures in 10 min, followed by a substantial decrease in the level of total protein phosphorylation activity in the nucleus. Curiously, this TCDD-induced decline in nuclear protein phosphorylation was accompanied by an increase in cytosolic and extranuclear protein phosphorylation activity. One of the main causes for such a decrease in the protein phosphorylation activity in the nucleus appears to be related to some increase in protein phosphatase activities as judged by the counteractions of okadaic acid and Na3VO4 to the above effect. In addition, TCDD induced changes in nuclear protein kinase activities as well. Manganese-stimulated protein kinase was found to be the predominant type of nuclear protein phosphorylating activity affected by TCDD, with 60% of the total activity due to heparin-sensitive casein kinase II (CK II), a major nuclear protein kinase. The level of CK II activity in the nuclear protein preparation from adipose tissue of TCDD-treated guinea pigs (1 microgram/kg) in the presence of 100 nM heparin was only 35% of the control value after 24 hr. In addition, TCDD was found to increase the protein kinase C and microtubule-associated protein 2 kinase activities as early as 15 min after treatment in isolated adipose tissues in culture. Under in situ incubation conditions with explant tissues in culture, TCDD rapidly enhanced the DNA binding activity of the transcriptional factor AP-1, whereas the same treatment reduced c-Myc DNA binding activity. Genistein, a specific protein tyrosine kinase inhibitor, abolished the stimulatory effect of TCDD on AP-1 binding activity, but not on DNA binding activity of c-Myc. Phorbol ester (TPA) increased the binding activity of AP-1 and c-Myc, as expected. However, TCDD in combination with TPA caused a slight reduction in binding activity of both transcriptional factors. On the other hand, in the presence of forskolin, the stimulatory effect of TCDD on AP-1 binding activity and the inhibitory effect on c-Myc were still apparent. Okadaic acid almost abolished the binding activity of c-Myc, whereas in combination with TCDD a stimulatory effect was found. These observations are consistent with the idea that TCDD regulates the DNA binding activity of AP-1 and c-Myc mainly through modulating their states of phosphorylation by altering protein kinase and phosphatase activities.
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PMID:Regulation by 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) of the DNA binding activity of transcriptional factors via nuclear protein phosphorylation in guinea pig adipose tissue. 748 34

Pulsatile GnRH regulates the biosynthesis and secretion of gonadotropins. Continuous administration of GnRH is known to desensitize gonadotropin secretion, but its effects on gonadotropin gene expression are less well characterized. We used a cell line of gonadotrope lineage (alpha T3 cells) to examine GnRH regulation of glycoprotein hormone alpha-subunit gene transcription. The alpha-subunit promoter, linked to a luciferase reporter gene (alpha LUC), was stably transfected into alpha T3 cells. Treatment with GnRH stimulated alpha LUC activity 3-fold. Stimulation of alpha LUC by GnRH was transient, with maximal activity after 6 h of treatment, followed by a return to baseline after 24 h. Stimulation of alpha-promoter activity by GnRH was inhibited entirely by a 10-fold molar excess of antide, a GnRH antagonist. Antide partially blocked GnRH stimulation even when added 4 h after GnRH, suggesting that a brief exposure to GnRH is not sufficient for maximal transcriptional stimulation. alpha LUC activity was also stimulated by treatment with 8-bromo-cAMP (3.5-fold), phorbol 12-myristate 13-acetate (TPA; 2.6-fold), or Bay K 8644 (3.3-fold). To assess whether the transient nature of GnRH stimulation was due to transcriptional desensitization, cells were pretreated with GnRH, followed by a second treatment with GnRH, cAMP, TPA, or Bay K. After pretreatment with GnRH, no further stimulation was seen after the addition of GnRH or TPA, but alpha LUC activity was further stimulated after the addition of either cAMP or Bay K. These findings indicate that the pathway for transcriptional activation by GnRH is desensitized and suggest that GnRH also desensitizes TPA-mediated stimulation. Similarly, pretreatment with TPA, but not cAMP or Bay K, prevented subsequent stimulation by GnRH. We conclude that GnRH transiently stimulates alpha gene transcription and that desensitization occurs with continuous exposure to GnRH, probably because of down-regulation of the protein kinase-C pathway.
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PMID:Gonadotropin-releasing hormone causes transcriptional stimulation followed by desensitization of the glycoprotein hormone alpha promoter in transfected alpha T3 gonadotrope cells. 750 27

The rat insulinoma beta-cell line RINm5F, which shares some homology with pancreatic islets, was used to study nitric oxide synthase induction. Nitric oxide is involved during beta-cell destruction and possibly in propagation of insulin-dependent diabetes mellitus. The cytokine interleukin-1 (IL-1) turned out to be the ultimate inducer, whereas tumour necrosis factor-alpha (TNF) and unexpectedly the phorbol ester TPA (12-O-tetradecanoylphorbol-13-acetate; 10 nM) synergistically promoted nitrite accumulation. Besides employing TPA directly, the synergistic effect of TNF could be traced back to protein kinase C activation since protein kinase C inhibitors (IC50 value for staurosporine: 4 nM) potently suppressed nitrite production in the case of IL-1/TNF administration. Further experiments using anti-TNF antibodies aimed to an autocrine loop following IL-1 addition to RINm5F cells, possibly involved in nitrite generation. Moreover, the nitric oxide synthase inductive IL-1 signal was antagonized by lipophilic cAMP analogues. Our results for nitrite accumulation in RINm5F cells point to activating protein kinase C and inhibitory protein kinase A signalling pathways.
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PMID:Modulation of inducible nitric oxide synthase in RINm5F cells. 751 91

The protein tyrosine phosphatase PTP-PEST is an 88 kDa cytosolic enzyme which is ubiquitously expressed in mammalian tissues. We have expressed PTP-PEST using recombinant baculovirus, and purified the protein essentially to homogeneity in order to investigate phosphorylation as a potential mechanism of regulation of the enzyme. PTP-PEST is phosphorylated in vitro by both cyclic AMP-dependent protein kinase (PKA) and protein kinase C (PKC) at two major sites, which we have identified as Ser39 and Ser435. PTP-PEST is also phosphorylated on both Ser39 and Ser435 following treatment of intact HeLa cells with TPA, forskolin or isobutyl methyl xanthine (IBMX). Phosphorylation of Ser39 in vitro decreases the activity of PTP-PEST by reducing its affinity for substrate. In addition, PTP-PEST immunoprecipitated from TPA-treated cells displayed significantly lower PTP activity than enzyme obtained from untreated cells. Our results suggest that both PKC and PKA are capable of phosphorylating, and therefore inhibiting, PTP-PEST in vivo, offering a mechanism whereby signal transduction pathways acting through either PKA or PKC may directly influence cellular processes involving reversible tyrosine phosphorylation.
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PMID:PTP-PEST: a protein tyrosine phosphatase regulated by serine phosphorylation. 752 Aug 67

We have investigated the regulatory role of PGI2 and its stable analogs, i.e., iloprost and cicaprost, on 12(S)-HETE- and TPA-enhanced tumor cell integrin expression and adhesion. Walker 256 carcinosarcoma cells express alpha IIb beta 3 integrin receptors, which mediate their adhesion to endothelium, subendothelial matrix and fibronectin. Adhesion is enhanced by treatment with exogenous 12(S)-HETE but not 12(R)-HETE or other lipoxygenase-derived hydroxy fatty acids, as well as by TPA. Both 12(S)-HETE and TPA enhanced alpha IIb beta 3 expression on W256 cells. PGI2 iloprost and cicaprost inhibited both 12(S)-HETE- and TPA-enhanced adhesion to endothelium and subendothelial matrix as well as alpha IIb beta 3 expression on W256 cells. The mechanism responsible for the effect of PGI2 was explored. Prostacyclin treatment of W256 cells resulted in an enhanced production of cAMP in a time- and dose-dependent manner. Pre-treatment of tumor cells with increasing concentrations of adenosine resulted in a dose-dependent decrease in the PGI2 effect on TPA or 12(S)-HETE-enhanced adhesion, suggesting that the PGI2 effect is mediated through PKA. Dibutyryl cAMP also blocked the 12(S)-HETE- or TPA-enhanced adhesion, and adenosine pre-treatment did not result in an inhibition of the dibutyryl cAMP effect. Collectively, our results suggest that the cyclooxygenase metabolite PGI2 can antagonize the lipoxygenase metabolite 12(S)-HETE- and TPA-enhanced alpha IIb beta 3 expression and tumor cell adhesion via activation of adenylate cyclase and elevation of intracellular levels of cAMP.
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PMID:Inhibition of TPA and 12(S)-HETE-stimulated tumor cell adhesion by prostacyclin and its stable analogs: rationale for their antimetastatic effects. 753 Feb 35

1. During osmotic swelling, cultured osteoblastic cells (ROS 17/2.8) exhibited activation of large amplitude Cl- currents in the whole-cell configuration of the patch-clamp technique. Effects of hypotonic shock on cell volume and membrane conductance were rapidly reversed on return to isotonic conditions. 2. Voltage command pulses in the range -80 to +50 mV produce instantaneous activation of Cl- currents. At potentials more positive than +50 mV the current exhibited time-dependent inactivation. The instantaneous current-voltage relationship was outwardly rectifying. 3. The anion permeability sequence of the induced current was SCN- (2.2) > i- (1.9) > Br- (1.5) > Cl- (1.0) > F- (0.8) > gluconate- (0.2). This corresponds to Eisenman's sequence I. 4. The volume-sensitive Cl- current was effectively inhibited by the Cl- channel blockers 4,4'- diisothiocyanatostilbene-2,2-disulphonic acid (DIDS) and 5-nitro-2-(3-phenylpropylamino) benzoic acid (NPPB). Outward currents were more effectively suppressed by DIDS than inward currents. The concentrations for 50% inhibition (IC50) of outward and inward currents were 81 and 298 microM, respectively. NPPB was equally effective at inhibiting outward and inward currents (IC50 of 64 microM). The current was relatively insensitive to diphenylamine-2-carboxylate (DPC), 500 microM producing only 22.5 +/- 4.0% inhibition. 5. Inhibitors of protein kinase A (H-89, 1 microM) and tyrosine kinase (tyrphostin A25, 200 microM) were without effect upon activation of Cl- currents in response to hypotonic shock. Under isotonic conditions, elevation of intracellular Ca2+ by ionomycin (1 microM) or activation of protein kinase C by 12-O-tetradecanoylphorbol 13-acetate (TPA, 0.1 microM) failed to evoke increases in basal Cl- conductance levels. 6. It is concluded that an outwardly rectifying Cl- conductance is activated upon osmotic swelling and may be involved in cell volume regulation of ROS 17/2.8 cells.
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PMID:Characterization of a volume-sensitive chloride current in rat osteoblast-like (ROS 17/2.8) cells. 756 9

Although changes in the expression of key steroidogenic enzymes such as cytochrome P450 cholesterol side-chain cleavage, 17 alpha-hydroxylase (P450c17), aldosterone synthase, and 3 beta-hydroxysteroid dehydrogenase (3 beta HSD) in the human adrenal cortex are known to be controlled by factors activating the protein kinase A or protein kinase C signaling pathways, little is known concerning the effects of increased intracellular Ca2+. In this study we describe the effects of K+, an agent known to increase intracellular Ca2+ through the opening of voltage-sensitive Ca2+ channels, on steroidogenesis in H295R human adrenocortical cells and corresponding changes in expression of these vital steroidogenic enzymes. Treatment of cells for 48 h with K+ (14 mM) resulted in an increase in aldosterone (3.5-fold) as well as the 17 alpha-hydroxylated steroids cortisol (2.9-fold) and dehydroepiandrosterone (DHEA; 3.7-fold). This action of K+ was accompanied by a dose-dependent (P < 0.05 at 6 mM K+ or above) and time-dependent (P < 0.05 at 24 h and beyond) increase in expression of P450c17 and, to a lesser extent, cytochrome P450 cholesterol side-chain cleavage messenger RNA (mRNA). Treatment with K+ also caused a time-dependent increase in aldosterone synthase mRNA levels, which were detectable by 12 h. Treatment with K+, however, was without effect on 3 beta HSD expression. These effects contrast with those of (Bu)2cAMP, which stimulated a greater increase in cortisol and DHEA secretion as well as P450c17 expression. The effects of K+ treatment also differ from those of AII, which promoted a greater aldosterone secretory response (5.7-fold), but a lesser effect on DHEA secretion (2.2-fold) and P450c17 expression. Although AII and TPA (known activators of protein kinase C) as well as forskolin and (Bu)2cAMP (known activators of protein kinase A) increased the expression of 3 beta HSD mRNA, K+ treatment was without effect, suggesting that elevation of [Ca2+]i in response to K+ did not activate the protein kinase C or protein kinase A signaling pathways. Furthermore, the effects of K+ on steroid secretion and 17 alpha-hydroxylase activity were reproduced by the voltage-sensitive Ca2+ channel activator BAYK 8644, and increases in P450c17 mRNA in response to K+ were reversed by the Ca2+ channel antagonist, nifedipine. We conclude that K+ can modulate the expression of key steroidogenic enzymes in H295R cells through the Ca2+ signaling pathway without involvement of the protein kinase A or protein kinase C pathways.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Ca(2+)-regulated expression of steroid hydroxylases in H295R human adrenocortical cells. 758 23

Basic fibroblast growth factor (bFGF) has been shown to be a potent mitogen and a promoter of angiogenesis. It has been hypothesized that the expression of the bFGF gene may be induced by stress of various types. To test that hypothesis, we investigated the expression of the bFGF gene during heat treatment in adriamycin-resistant (MCF-7/ADR) and -sensitive (MCF-7) human breast carcinoma cells. Under normal growth conditions, the bFGF mRNA was detected in MCF-7/ADR cells, while it was not detectable in MCF-7 cells by Northern blot analysis. During heating at 41 degrees C, the level of bFGF mRNA increased in MCF-7/ADR cells and the message became detectable in the MCF-7 cell line. However, after continuous heating at 41 degrees C for 24 h, the bFGF mRNA level decreased to control level in MCF-7/ADR cells. Interestingly, simultaneous treatment with heat and 60 micrograms/ml H-7 (1-(isoquinolinylsulfonyl)-2-methylpiperazine, a potent PKC inhibitor) decreased the level of bFGF mRNA in MCF-7/ADR cells. These results suggest that a protein kinase, likely PKC, is involved in the transcriptional regulation of the heat-enhanced bFGF gene expression in human breast carcinoma cells. Although no heat shock element can be identified in the promoter of the bFGF gene, we observed that the AP-1 binding activity to a TPA responsive element (TRE)-like sequence in the promoter of bFGF gene was enhanced by heat, as tested by mobility shift assay. Antibody developed against the c-Jun and c-Fos proteins inhibited the AP-1 binding activity to TRE. Therefore, the AP-1 complex appears to be responsible for the heat-enhanced binding to the TRE-like motif of the bFGF gene. Furthermore, the increased AP-1 binding activity does not require new protein synthesis but activation of the preexisting c-Jun proteins.
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PMID:Heat-induced bFGF gene expression in the absence of heat shock element correlates with enhanced AP-1 binding activity. 762 86

We have studied two proteins potentially involved in the regulation of the 25-OH-D-1-hydroxylase, which is located in the renal mitochondria and which is responsible for the production of the steroid hormone 1,25(OH)2D3. The endogenous inhibitor of cyclic AMP-dependent protein kinase, PKI, is down regulated by 1,25(OH)2D3. Having cloned and sequenced PKI cDNA, we studied its message levels and found them to be regulated by 1,25(OH)2D3 tissue specifically in the kidney and in kidney cell culture. In other experiments we over expressed the ferredoxin component of the 1-hydroxylase and found it to be physically and chemically indistinguishable from those of classic steroidogenic tissues. The mRNA encoding the ferredoxin component is up-regulated by chronic vitamin D deficiency, which at the same time leads to sustained elevation in 1-hydroxylase activity; no short term effect of 1,25(OH)2D3 on ferredoxin mRNA in kidney cell culture could be demonstrated. Finally, there was an association between decreased phosphorylation of ferredoxin and decreased 1-hydroxylase activity brought about by treatment of cultured kidney cells with TPA. Control of the renal signaling events involved in the production of 1,25(OH)2D3 remains a fruitful area of investigation in the field of the metabolism and actions of vitamin D and its metabolites.
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PMID:Regulation of the ferredoxin component of renal hydroxylases at transcriptional and postranslational levels and of the protein inhibitor of cyclic AMP-dependent kinase. 762 15

The adult mammalian temporomandibular joint (TM) disc is a fibrocartilaginous tissue that undergoes normal developmental remodeling, requiring removal of the existing extracellular matrix and its replacement by new matrix macromolecules. This remodeling is probably mediated by matrix-degrading enzymes, but to date none has been demonstrated in association with the TMJ disc. We characterized, identified, and determined the regulation of proteinases and proteinase inhibitor (PIs) synthesized by TMJ disc cells in organ and cell cultures. TMJ discs were retrieved from 14-week-old male NZW rabbits and both tissue- and disc-derived cells were cultured in serum-free medium. The conditioned media were retrieved at 12-hour intervals and assayed for proteinases and PIs in gelatin- and casein-impregnated polyacrylamide gels. Three proteinases with gelatinolytic activities at 92 kDa, 72 kDa, and 42/57 kDa and one caseinolytic activity at 51/54 kDa were detected. All were inhibited by 1,10-1 phenanthroline, thus characterizing these enzymes as matrix metalloproteinases (MMPs), most likely 92-kDa gelatinase (proMMP-9), 72-kDa gelatinase (proMMP-2), procollagenase (proMMP-1), and prostromelysin (proMMP-3). The identity of the latter two MMPs was confirmed by Western blots. Two PIs and 30 kDa and 20 kDa, probably tissue inhibitors of metalloproteinase (TIMP) and TIMP-2, were observed on reverse zymograms. TPA, a protein kinase-C agonist, increased the expression of 92-kDa gelatinase and 30-kDa PI by both explanted discs and isolated disc cells. The profile of MMPs constitutively expressed by disc cells is similar to that of synovial fibroblasts but different from that of chondrocytes.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Characterization and identification of proteinases and proteinase inhibitors synthesized by temporomandibular joint disc cells. 762 41


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