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

Nitric oxide (NO) upregulates ciliary beat frequency (CBF). The present study evaluates mechanisms of the NO-cyclic guanosine monophosphate (cGMP) pathway regulation of CBF. Rat tracheal explants were loaded with 4,5-diaminofluorescein diacetate for the demonstration of NO production by ciliated epithelial cells after L-arginine (L-Arg) stimulation. CBF was measured using phase contrast microscopy and videotape analysis. The roles of NO, soluble guanylate cyclase (sGC), cGMP-dependent protein kinase (PK) G, and phosphodiesterase (PDE) V in regulation of CBF were evaluated. NO synthase (NOS) was activated with L-Arg or inhibited with N(G)-monomethyl-L-Arg. sGC was stimulated with NO donors 1-hydroxy-2-oxo-3- (N-ethyl-2-aminoethyl)-3-ethyl-1-triazene and S-nitroso-L-glutathione or mimicked by 8-bromo-guanosine 3', 5'-cyclic monophosphate (8-Br-cGMP) and inhibited with 1H-[1,2, 4]oxadiazole[4,3-a]quinoxalin-1-one. The effects of the PKG inhibition with KT5823 and PDE V inhibition with Zaprinast were also examined. The studies demonstrate that ciliated epithelial cells produce NO, which is correlated with CBF stimulation. L-Arg dose- and time-dependently increases CBF, and NO donors, 8-Br-cGMP, and Zaprinast also enhance CBF. Inhibitors of NOS, sGC, and PKG can block the stimulant effect of L-Arg on CBF. Thus, NO is a regulator of CBF acting via sGC and PKG. The NO-cGMP signaling pathway regulates CBF in an autocrine manner in cultured rat ciliated airway epithelium.
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PMID:Regulation of ciliary beat frequency by the nitric oxide-cyclic guanosine monophosphate signaling pathway in rat airway epithelial cells. 1091 83

1. The effects of authentic NO and the NO donor S-nitroso-N-acetylpenicillamine (SNAP) on swelling-activated chloride currents (Iswell) were investigated in freshly dispersed rabbit portal vein smooth muscle cells. Iswell was recorded with the perforated patch configuration of the whole-cell patch clamp technique. 2. In approximately 50 % of cells NO and SNAP inhibited the amplitude of Iswell by about 45 % in a voltage-independent manner. Iswell was also inhibited by an inhibitor of NO-sensitive guanylate cyclase (1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one (ODQ) and by KT5823, an inhibitor of cGMP-dependent protein kinase. 3. In other cells both NO and SNAP enhanced Iswell by about 40 % in a voltage-independent manner. A similar increase was produced by application of the cell-permeable cGMP analogue 8-bromo-guanosine 3', 5'-cyclic monophosphate (8-Br-cGMP). However, 8-Br-cGMP had no effect on current amplitude in cells pre-treated with KT5823. In contrast 8-Br-cGMP increased the amplitude of Iswell in cells which had been pre-treated with ODQ. 4. SNAP also modulated Iswell recorded in the conventional whole-cell configuration with internal solutions containing 10 mM EGTA to rule out any contribution from Ca2+-activated Cl- currents. 5. These data suggest that the amplitude of Iswell can be enhanced by NO via a cGMP-dependent phosphorylation and inhibited by NO in a cGMP-independent manner.
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PMID:Dual modulation of swelling-activated chloride current by NO and NO donors in rabbit portal vein myocytes. 1101 99

Estrogen increases secretion of cervical mucus in women, and the effect depends on fragmentation of the cytoskeleton. The objective of the present study was to understand the molecular mechanism of estrogen action. Treatment of human cervical epithelial cells with 17beta-estradiol, sodium nitroprusside (SNP), or 8-bromoguanosine 3', 5'-cyclic monophosphate (8-Br-cGMP) increased cellular monomeric G-actin and decreased polymerized F-actin. The effects of estradiol were blocked by tamoxifen, by the guanylate cyclase inhibitor LY-83583, and by the cGMP-dependent protein kinase inhibitor KT-5823. The effects of SNP were blocked by LY-83583 and KT-5823, while the effects of 8-Br-cGMP were blocked only by KT-5823. Treatment with phalloidin decreased paracellular permeability and G-actin. Treatment with 17beta-estradiol, SNP, or 8-Br-cGMP attenuated SNP-induced phosphorylation of [(32)P]adenylate NAD in vitro: tamoxifen blocked the effect of estrogen; LY-83583 blocked the effect of SNP but not that of 8-Br-cGMP, while KT-5823 blocked effects of both SNP and 8-Br-cGMP. These results indicate that estrogen, nitric oxide (NO), and cGMP stimulate actin depolymerization. A possible mechanism is NO-induced, cGMP-dependent protein kinase augmentation of ADP-ribosylation of monomeric actin.
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PMID:cGMP-dependent ADP depolymerization of actin mediates estrogen increase in cervical epithelial permeability. 1107 20

ATP and UTP induced a dual inotropic effect in rat left atria: first a decrease and then an increase in contractile tension were observed. PPADS, an antagonist of P2X receptors, inhibited positive inotropism induced by ATP and alpha,beta-meATP. Chiefly, we investigated intracellular mechanisms responsible for the positive inotropism. We tested cromakalim and glibenclamide, an activator and an inhibitor, respectively, of ATP-sensitive K(+) channels. These compounds did not influence the effects of ATP. IBMX, a phosphodiesterase inhibitor, and H-7, an inhibitor of protein kinase C and cAMP-dependent protein kinase, did not modify the inotropic effects of ATP. Instead, H-8, an inhibitor of cAMP- and cGMP-dependent protein kinases, strongly inhibited the positive effects of both ATP and UTP, suggesting the possible involvement of cGMP in the inotropism. Also, LY 83583, an inhibitor of cGMP production, reduced positive inotropism by alpha,beta-meATP, ATP and UTP. Moreover, 8-Br-cGMP (50 microM), a stable analogue of cGMP, inhibited positive inotropism by all nucleotides. Lastly, we determined intracellular cGMP levels by RIA; the cyclic nucleotide increased during positive inotropism induced by ATP and UTP. The results regarding positive inotropism suggest that: (a) ATP acts through P2X receptors, while UTP may act by P2X, but also through PPADS-insensitive receptors; and (b) changes in intracellular cGMP concentration are involved in this inotropic effect.
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PMID:Do ATP and UTP involve cGMP in positive inotropism on rat atria? 1123 39

We tested both relaxation and cGMP generation by atrial (ANP), brain (BNP), and C-type natriuretic peptide (CNP) in oxytocin-stimulated myometrium from near-term pregnant guinea pigs to investigate the ability and mechanism of natriuretic peptides to inhibit myometrial contractility. Myometrial strips were contracted by 10(-8) M oxytocin, and relaxation to the cumulative addition (10(-9)-10(-6) M) of the natriuretic peptides measured. Maximal relaxation to BNP was significantly greater than to ANP (52 versus 32% respectively; p < 0.05), whereas CNP failed to produce relaxation. However, the increase in cGMP produced by BNP (10(-7) M) was significantly less than that produced by ANP (10(-7) M) (4.5 versus 7.0 times basal; p < 0.05); CNP did not increase myometrial cGMP. Anantin, a competitive blocker of the guanylate cyclase A receptor, significantly reduced the increase in cGMP produced by ANP and BNP, but had no effect on relaxation induced by either peptide. Rp-8-Br-cGMP, an inhibitor of the cGMP-dependent protein kinase, did not alter BNP-induced relaxation. The atrial natriuretic peptide-fragment 4-23 amide, a natriuretic peptide clearance receptor agonist, failed to inhibit oxytocin-stimulated myometrial contraction. We conclude that natriuretic peptide induced relaxation of oxytocin-stimulated myometrium from the pregnant guinea pig is not mediated by either guanylate cyclase A or B activation, is independent of the cGMP pathway, and does not involve clearance receptor activation. Our results suggest that natriuretic peptide-induced relaxation of pregnant myometrium is mediated via a novel mechanism.
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PMID:Natriuretic peptide-induced relaxation of myometrium from the pregnant guinea pig is not mediated by guanylate cyclase activation. 1125 43

1.Voltage-gated K+ channels containing Kv3 subunits play specific roles in the repolarization of action potentials. Kv3 channels are expressed in selective populations of CNS neurons and are thought to be important in facilitating sustained and/or repetitive high frequency firing. Regulation of the activity of Kv3 channels by neurotransmitters could have profound effects on the repetitive firing characteristics of those neurons. 2.Kv3 channels are found in several neuronal populations in the CNS that express nitric oxide synthases (NOSs). We therefore investigated whether Kv3 channels are modulated by the signalling gas nitric oxide (NO). 3. We found that Kv3.1 and Kv3.2 currents are potentially suppressed by D-NONOate and other NO donors. The effects of NO on these currents are mediated by the activation of guanylyl cyclase (GC), since they are prevented by Methylene Blue, an inhibitor of GC, and by ODQ, a specific inhibitor of the soluble form of GC. Moreover, application of 8-Br-cGMP, a permeant analogue of cGMP, also blocked Kv3.1 and Kv3.2 currents. 4.KT5283, a cGMP-dependent protein kinase (PKG) blocker, prevented the inhibition of Kv3.1 and Kv3.2 currents by D-NONOate and 8-Br-cGMP. This indicates that activation of PKG as a result of the increase in intracellular cGMP levels produced by D-NONOate or 8-Br-cGMP is necessary for channel block. 5. Although the effects of NO on Kv3.1 and Kv3.2 channels require PKG activity, two observations suggest that they are not mediated by phosphorylation of channel proteins: (a) the reagents affect both Kv3.2 and Kv3.1 channels, although only Kv3.2 proteins have a putative PKA-PKG phosphorylation site, and (b) mutation of the PKA-PKG phosphorylation site in Kv3.2 does not interfere with the effects of NO or cGMP. 6. The inhibitory effects of NO and cGMP on Kv3.1 and Kv3.2 currents appear to be mediated by the activation of serine-threonine phosphatase, since they are blocked by low doses of okadaic acid. Furthermore, direct intracellular application of the catalytic subunit of protein phosphatase 2A inhibited Kv3.2 currents, indicating that activity of PKG-induced phosphatase is necessary and sufficient to inhibit these channels. 7. The results suggest that basal phosphorylation of Kv3 channel proteins is required for proper channel function. Activation of phosphatases via NO or other signals that increase cGMP might be a potent mechanism to regulate Kv3 channel activity in neurons.
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PMID:Modulation of Kv3 potassium channels expressed in CHO cells by a nitric oxide-activated phosphatase. 1128 Nov 23

The expression and phosphorylation state of the vasodilator-stimulated phosphoprotein (VASP), a membrane-associated focal adhesion protein, was investigated in human neutrophils. Adhesion and spreading of neutrophils induced the rapid phosphorylation of VASP. The phosphorylation of VASP was dependent on cell spreading, as VASP was expressed as a dephosphorylated protein in round adherent cells and was phosphorylated at the onset of changes in cell shape from round to spread cells. Immunofluorescence microscopy demonstrated that VASP was localized at the cell cortex in round cells and redistributed to focal adhesions at the ventral surface of the cell body during cell spreading. Dual labeling of spread cells indicated that VASP was colocalized with F-actin in filopodia and in focal adhesions, suggesting that the phosphorylation of VASP during cell spreading may be involved in focal adhesion complex organization and actin dynamics. VASP is a prominent substrate for both cGMP-dependent protein kinase (cGK) and cAMP-dependent protein kinase. Evidence suggested that cGK regulated neutrophil spreading, as both VASP phosphorylation and neutrophil spreading were inhibited by Rp-8-pCPT-cGMPS (cGK inhibitor), but not KT5720 (cAMP-dependent protein kinase inhibitor). In contrast, neutrophil spreading was accelerated when cGMP levels were elevated with 8-Br-cGMP, a direct activator of cGK. Furthermore, the same conditions that lead to VASP phosphorylation during neutrophil adherence and spreading induced significant elevations of cGMP in neutrophils. These results indicate that cGMP/cGK signal transduction is required for neutrophil spreading, and that VASP is a target for cGK regulation.
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PMID:The vasodilator-stimulated phosphoprotein is regulated by cyclic GMP-dependent protein kinase during neutrophil spreading. 1131 94

Nitric oxide (NO), an endothelium-dependent relaxing factor, regulates relaxation, proliferation, and migration of smooth muscle cells (SMCs) and most likely attenuates developing vascular disease such as atherosclerosis. We investigated whether or not NO is associated with regulation of aortic elasticity. S-Nitrosoglutathione (GSNO), a NO donor, stimulated tropoelastin synthesis in cultured SMCs during both the quiescent and proliferating phases. The stimulation of tropoelastin synthesis was dose-dependent within 1-100 nM. Maximum stimulation was detected by treatment with 100 nM GSNO for 24 h. 8-Bromoguanosine 3',5'-cyclic monophosphate (8-Br-cGMP), an exogenous cyclic GMP analog, also upregulated tropoelastin synthesis. Tropoelastin and lysyl oxidase mRNA expression, as assessed by Northern blot analysis, was also stimulated by GSNO. Administration of KT5823, a cyclic GMP-dependent protein kinase inhibitor, inhibited the GSNO-induced tropoelastin synthesis. These results indicate that the stimulatory effects of GSNO are due to cyclic GMP dependent protein kinase (PKG) activation by NO. In conclusion, NO seems to enhance aortic elasticity via tropoelastin and lysyl oxidase upregulation.
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PMID:Nitric oxide stimulates elastin expression in chick aortic smooth muscle cells. 1137 60

Rat vascular smooth muscle cells (VSMCs) express at least two mRNAs for K-Cl cotransporters (KCC): KCC1 and KCC3. cGMP-dependent protein kinase I regulates KCC3 mRNA expression in these cells. Here, we show evidence implicating the nitric oxide (NO)/cGMP signaling pathway in the expression of KCC1 mRNA, considered to be the major cell volume regulator. VSMCs, expressing soluble guanylyl cyclase (sGC) and PKG-I isoforms showed a time- and concentration-dependent increase in KCC1 mRNA levels after treatment with sodium nitroprusside as demonstrated by semiquantitative RT-PCR. sGC-dependent regulation of KCC1 mRNA expression was confirmed using YC-1, a NO-independent sGC stimulator. The sGC inhibitor LY83583 blocked the effects of sodium nitroprusside and YC-1. Moreover, 8-Br-cGMP increased KCC1 mRNA expression in a concentration- and time-dependent fashion. The 8-Br-cGMP effect was partially blocked by KT5823 but not by actinomycin D. However, actinomycin D and cycloheximide increased basal KCC1 mRNA in an additive manner, suggesting different mechanisms of action for both drugs. These findings suggest that in VSMCs, the NO/cGMP-signaling pathway participates in KCC1 mRNA regulation at the post-transcriptional level.
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PMID:Nitric oxide signaling pathway regulates potassium chloride cotransporter-1 mRNA expression in vascular smooth muscle cells. 1155 13

The effect of nitric oxide on p11 expression was studied in an immortalized human bronchial epithelial cell line (BEAS-2B cells). Three nitric oxide donors were used: spermine NONOate (SP), (+/-)-S-nitroso-N-acetylpenicillamine (SNAP), and S-nitrosoglutathione (SNOG). All three nitric oxide donors had similar effects resulting in dose-dependent and time-dependent accumulation of p11 protein and an increase of steady-state p11 mRNA. Studies using a reporter gene containing the region from -1499 to +89 of the p11 promoter demonstrated an increase in transcriptional activity after stimulation with NO donors for 4 h. These effects were abolished at the promoter and protein level using protein kinase G inhibitors (KT5823 and R(p)-8-pCPT-cGMPS). Incubation of transfected cells with a cell permeable cGMP analogue (8-Br-cGMP) resulted in a dose-related increase of promoter activity. An electrophoretic mobility shift assay of nuclear proteins extracted from BEAS-2B cells identified an AP-1 site located at -82 to -77 of the p11 promoter region as an NO- and cGMP- dependent response element. These data were confirmed using a c-jun dominant negative mutant vector and a c-jun expression plasmid. Therefore, we conclude that nitric oxide-induced p11 expression in human bronchial epithelial cells is mediated at least in part through increased binding of activator protein one to the p11 promoter.
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PMID:p11 expression in human bronchial epithelial cells is increased by nitric oxide in a cGMP-dependent pathway involving protein kinase G activation. 1157 Dec 84


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