Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:4.6.1.1 (adenylate cyclase)
19,190 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Further decoding of a novel adenylyl cyclase signaling mechanism (ACSM) of the action of insulin and related peptides detected earlier (Pertseva et al. Comp Biochem Physiol B Biochem Mol Biol 1995;112:689-95 and Pertseva et al. Biochem Pharmacol 1996;52:1867-74) was carried out with special attention given to the role of protein kinase C (PKC) in the ACSM. It was shown for the first time that transduction of the insulin signal via the ACSM followed by adenylyl cyclase (AC, EC 4.6.1.1) activation was blocked in the muscle tissues of rat and mollusc Anodonta cygnea in the presence of pertussis toxin, inducing the impairment of G(i)-protein function, wortmannin, an inhibitor of phosphatidylinositol 3-kinase (PI3-K), and calphostin C, a blocker of PKC. The cholera toxin treatment of muscle membranes led to an increase in basal AC activity and a decrease in enzyme insulin reactivity. Phorbol ester and diacylglycerol activation of PKC (acute treatment) induced the inhibition of the insulin AC activating effect. This negative influence was also observed in the case of the AC system activated by biogenic amines. It was first concluded that the ACSM of insulin action involves the following signaling chain: receptor tyrosine kinase => G(i) (betagamma) => PI3-K => PKCzeta (?) => G(s) => AC => adenosine 3',5'-cyclic monophosphate. It was also concluded that the PKC system has a dual role in the ACSM: (1) a regulatory role (PKC sensitive to phorbol esters) that is manifested as a negative feedback modulation of insulin signal transduction via the ACSM; (2) a transductory role, which consists in direct participation of atypical PKC (PKCzeta) in the process of insulin signal transduction via the ACSM.
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PMID:A dual role of protein kinase C in insulin signal transduction via adenylyl cyclase signaling system in muscle tissues of vertebrates and invertebrates. 1132 32

We have previously demonstrated that endothelin (ET)-1 and its subtype A receptor (ET-AR) expression are increased in lung under hypoxic conditions and that activation of ET-AR by ET-1 is a major mediator of hypoxia-induced pulmonary hypertension in the rat. The present study tested the hypothesis that the hypoxia-responsive tyrosine kinase receptor-activating growth factors fibroblast growth factor (FGF)-1, FGF-2, and platelet-derived growth factor (PDGF)-BB stimulate expression of the ET-AR in pulmonary arterial smooth muscle cells (PASMCs). Quiescent rat PASMCs were incubated under hypoxia (1% O2), or with FGF-1, FGF-2, PDGF-BB, vascular endothelial growth factor, ET-1, angiotensin II, or atrial natriuretic peptide under normoxic conditions for 24 h. FGF-1 and -2 and PDGF-BB, but not hypoxia, vascular endothelial growth factor, ET-1, angiotensin II, or atrial natriuretic peptide, significantly increased ET-AR mRNA levels. FGF-1-induced ET-AR expression was inhibited by FGF-receptor inhibitor PD-166866, MEK inhibitor U-0126, transcription inhibitor actinomycin D, and translation inhibitor cycloheximide. In contrast, the stimulatory effect of FGF-1 on ET-AR mRNA expression was not altered by PI3 kinase, PKA, PKC, or adenylate cyclase inhibitors. PASMC ET-AR gene transcription, assessed by nuclear-runoff analysis, was increased by FGF-1. These results provide novel finding that ET-AR in PASMCs in vitro is unresponsive to hypoxia per se but is robustly simulated by tyrosine kinase receptor-associated growth factors (FGF-1, FGF-2, PDGF-BB) that themselves are stimulated by hypoxia in lung. This observation suggests a novel signaling mechanism that may be responsible for overexpression of ET-AR in lung, and may contribute to the hypoxia-induced pulmonary vasoconstriction, hypertension, and vascular remodeling in hypoxia-adapted animal.
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PMID:Fibroblast growth factor mediates hypoxia-induced endothelin-- a receptor expression in lung artery smooth muscle cells. 1285 19

Melanophores are pigmented cells capable of quick colour changes through coordinated transport of their intracellular pigment granules. We demonstrate the involvement of phosphoinositide 3-kinase (PI3-K) in Xenopus and Labrus aggregation by the use of the PI3-K inhibitor, LY-294002. In Xenopus, wortmannin-insensitive PI3-K was found to be essential for the aggregation, mitogen-activated protein kinase (MAPK) activation and tyrosine phosphorylation of a 280-kDa protein, and for the maintenance of low cyclic adenosine 3':5'-monophosphate (cAMP) during the aggregated state. Pre-aggregated cells disperse completely to LY-294002 at 50-100 muM, involving a transient elevation in cAMP due to adenylate cyclase (AC) stimulation or to inhibition of cyclic nucleotide phosphodiesterase (PDE). The inactive analogue LY-303511 did not induce dispersion at the same concentrations. PDE4 and/or PDE2 was found to be involved in melanosome aggregation. The similar kinetics of LY-294002 and various PDE inhibitors indicates that the elevation of cAMP might be due to inhibition of PDE. In Labrus melanophores, LY-294002 had a less dramatic effect, probably due to less dependence on PDE in regulation of cAMP levels. In Xenopus aggregation, we suggest that melatonin stimulation of the Mel1c receptor via G(beta gamma) activates PI3-K that, directly or indirectly via MAPK, activates PDE.
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PMID:Phosphoinositide 3-kinase is involved in Xenopus and Labrus melanophore aggregation. 1457 67

We have previously shown that, in glioma C6 cells, two nucleotide ADP-sensitive receptors coexist: P2Y1, coupled to PLC and responsible for Ca2+ release, and P2Y12, negatively coupled to adenylate cyclase. In the present study, we examined the effects of the stimulation of these two receptors on ERK1/2 and PI3-K activation, and cell proliferation in either serum-deprived or nonstarved C6 cells. In response to ADP and its analogues, in serum-starved cells, both p44 ERK1 and p42 ERK2 were activated in a time-dependent manner, as monitored by Western blot analysis using an antiphospho-p42/p44 MAPK antibody. The phosphorylation was reduced both by removal of the extracellular Ca2+ and partially or almost completely by MRS2179 or AR-C69931MX, specific antagonists of the P2Y1 and P2Y12 receptors, respectively. The inhibitory effect of antagonists was additive. These data indicate the involvement of both receptors, P2Y1 and P2Y12, in the ERK1/2 activation, but the P2Y12 receptor contribution predominates. ERK1/2 activity was positively correlated with cell proliferation of cultured glioma C6 cells. In nonstarved cells, ADP markedly decreased the PI3-K activity. In contrast, in serum-starved cells, ADP evoked an increase in the PI3-K activity. Blocking of the P2Y1 receptor by MRS2179 additionally increased this ADP response. These results suggest that the P2Y1 receptor has an inhibitory and the P2Y12 receptor a stimulatory effect on PI3-K signalling pathway. RT-PCR analysis revealed different mRNA expression of both receptors in starved and nonstarved cells. In nonstarved cells, the P2Y1 receptor mRNA predominates, whereas in serum-deprived cells the expression of P2Y12 mRNA becomes more pronounced. British Journal of Pharmacology (2004) 141, 497-507. doi:10.1038/sj.bjp.0705639
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PMID:Differential effects of P2Y1 and P2Y12 nucleotide receptors on ERK1/ERK2 and phosphatidylinositol 3-kinase signalling and cell proliferation in serum-deprived and nonstarved glioma C6 cells. 1471 52

We here show that GLP-1 and the long-acting GLP-1 analogue, liraglutide, interfere with diabetes-associated apoptotic processes in the beta-cell. Studies using primary neonatal rat islets showed that native GLP-1 and liraglutide inhibited both cytokine- and free fatty acid-induced apoptosis in a dose-dependent manner. The anti-apoptotic effect of liraglutide was mediated by the GLP-1 receptor as the specific GLP-1 receptor antagonist, exendin(9-39), blocked the effects. The adenylate cyclase activator, forskolin, had an anti-apoptotic effect similar to those of GLP-1 and liraglutide indicating that the effect was cAMP-mediated. Blocking the PI3 kinase pathway using wortmannin but not the MAP kinase pathways by PD98059 inhibited the effects of liraglutide. In conclusion, GLP-1 receptor activation has anti-apoptotic effect on both cytokine, and free fatty acid-induced apoptosis in primary islet-cells, thus suggesting that the long-acting GLP-1 analogue, liraglutide, may be useful for retaining beta-cell mass in both type 1 and type 2 diabetic patients.
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PMID:The long-acting glucagon-like peptide-1 analogue, liraglutide, inhibits beta-cell apoptosis in vitro. 1579 22

Herpes simplex viruses types 1 (HSV-1) and 2 (HSV-2) are associated with a wide range of diseases related to infection of epithelial or neuronal tissues. The two viruses evidence distinct pathogenesis aspects, which are likely mediated by distinct viral genes. One such gene is UL39, which codes for the large subunit of ribonucleotide reductase (R1, also known as ICP6 and ICP10 for HSV-1 and HSV-2 respectively). The HSV-2 R1 has serine-threonine protein kinase (PK) activity, which is located within the first 411 amino acids (ICP10PK). ICP10PK is a constitutively activated growth factor receptor (GFR) that signals through the Ras/MEK/ERK pathway. It has transforming activity in immortalized cells, mitogenic (but not transforming) activity in normal diploid cells, and anti-apoptotic (survival) activity in post mitotic neurons in the central nervous system (CNS). In addition to the Ras/MEK/ERK, ICP10PK also activates the PI3-K/Akt pathway, upregulates the Ras family member Rap-1 and adenylate cyclase and activates the B-Raf kinase activity. ICP10 PK appears to have a cellular origin. Its conservation is most likely to reflect the ability to impart an evolutionary advantage, particularly in the face of pro-apoptotic viral genes. Indeed, activation of the Ras/MEK/ERK pathway by ICP10PK is required for virus growth.
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PMID:The herpes simplex virus type 2 protein ICP10PK: a master of versatility. 1597 May 36

Antidepressant drugs inhibit the corticotropin-releasing-hormone (CRH) gene promoter activity in the differentiated Neuro-2A cells, but a molecular mechanism of their action has been poorly recognized. The aim of the present study was to elucidate the involvement of some intracellular signal transduction pathways in imipramine-induced inhibition of CRH gene activity in the differentiated Neuro-2A cells, stably transfected with a human CRH promoter fragment linked to the chloramphenicol acetyltransferase (CAT) reporter gene. It was found that wortmannin (0.1muM), an inhibitor of phosphatidylinositol 3-kinase (PI3-K) and forskolin (10, 25muM), an activator of adenylate cyclase enhanced the basal activity of CRH gene promoter, whereas inhibitors of protein kinase A, calcium/calmodulin kinase (CaMK) and mitogen-activated protein kinase (MAPK) had opposite effects. Moreover, wortmannin at a low concentration (0.01muM) significantly reversed the inhibitory effect of imipramine on CRH-CAT activity, whereas other protein kinase inhibitors were inactive or even enhanced the imipramine effects. The involvement of PI3-K/Akt pathway in the imipramine action was confirmed by Western blot study, which showed that this drug increased phospho-Ser-473 Akt level, but had no effect on total Akt and glycogen synthase kinase (GSK-3beta) levels. These results indicate that the inhibitory effect of imipramine on the CRH gene promoter activity in Neuro-2A cells is mainly connected with enhancement of PI-3K/Akt pathway.
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PMID:Inhibitory effect of imipramine on the human corticotropin-releasing-hormone gene promoter activity operates through a PI3-K/AKT mediated pathway. 1599 64

ADP activates human platelets through two G-protein coupled receptors, P2Y1 and P2Y12, to induce a range of functional responses. Here we have addressed the role and mechanism of P2Y12 in modulating ADP-induced platelet shape change. Although the response depended upon activation of P2Y1, it was potentiated by P2Y12 as the P2Y12-selective antagonists AR-C69931MX and 2MeSAMP partially inhibited shape change in the later phase of the response. This was paralleled by inhibition of pseudopod formation, platelet spheration, actin polymerisation and myosin light chain phosphorylation. P2Y12 is known to couple to activation of PI3 kinase and inhibition of adenylate cyclase, but we showed that neither of these signalling events couples to regulation of shape change by this receptor. However, by assessment of phosphorylation of its major substrate myosin light chain phosphatase, we provide direct evidence for activation of Rho kinase by ADP, and that although P2Y1 is required for activation of Rho kinase, P2Y12 is able to potentiate its activity. We conclude that P2Y12 plays a potentiatory role in ADP-induced shape change through regulation of the Rho kinase pathway, potentiating both myosin phosphorylation and actin polymerisation, and this forms part of an important signalling pathway additional to its well-established Gi-coupled pathways.
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PMID:Evidence that the purinergic receptor P2Y12 potentiates platelet shape change by a Rho kinase-dependent mechanism. 1623 3

Trypanosoma cruzi metacyclic trypomastigotes of the major phylogenetic lineages use specific signaling pathways to invade host cells. Using a panel of drugs, we studied if the differences in the ability of extracellular amastigotes (EA) from G (T. cruzi I) and CL (T. cruzi II) strains to invade host cells could be associated to activation of specific signaling routes. Sonicated extracts from G or CL strain EA induced transient raises in HeLa cell intracellular Ca(2+) levels in a dose-dependent manner. Treatment of EA with drugs that affect Ca(2+) release from inositol-1,4,5-triphosphate-sensitive stores did not significantly affect the infectivity of either strain, whereas EA of both strains treated with ionomycin plus NH(4)Cl or nigericin that release Ca(2+) from acidocalcisomes had their infectivity reduced. Treatment of parasites with adenylate cyclase activator forskolin increased the infectivity of both strains towards HeLa cells. These data, taken together, suggest that, for host cell invasion, G and CL strain EA engage signaling pathways that lead to an increase of cyclic adenosine monophosphate and Ca(2+) mobilization from acidocalcisomes. Moreover, treatment of EA with genistein reduced by approximately 45% the invasion of HeLa cells by G but not by CL strain, implicating a protein tyrosine kinase in the process. In line with this, HeLa cell extracts contained a protein tyrosine kinase activity that mediated the phosphorylation of 87- and 175-kDa polypeptides of EA from G but not from CL strain. Regarding the target cell response, the activation of host PI3 kinase appears to be required for invasion by either strain as treatment of HeLa cells with wortmannin reduced EA infectivity. These data overall reinforce the concept that cell invasion by T. cruzi EA markedly differs from the process involving metacyclic trypomastigotes.
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PMID:Cell invasion by Trypanosoma cruzi amastigotes of distinct infectivities: studies on signaling pathways. 1679 32

Aquaporin8 (AQP8) is a transmembrane water channel that is found mainly in hepatocytes. The direct involvement of AQP8 in high glucose condition has not been established. Therefore, this study examined the effects of high glucose on AQP8 and its related signal pathways in primary cultured chicken hepatocytes. High glucose increased the movement of AQP8 from the intracellular membrane to plasma membrane in a 30 mM glucose concentration and in a time- (> or =10 min) dependent manner. On the other hand, 30 mM mannitol did not affect the translocation of AQP8, which suggested the absence of osmotic effect. Thirty millimolar glucose increased intracellular cyclic adenosine 3, 5-monophosphate (cAMP) level. Moreover, high glucose level induced Akt phosphorylation, protein kinase C (PKC) activation, p44/42 mitogen-activated protein kinases (MAPKs), p38 MAPK, and c-jun NH2-terminal kinase (JNK) phosphorylation. On the other hand, inhibition of each pathway by SQ 22536 (adenylate cyclase inhibitor), LY 294002 (PI3-K phosphatidylinositol 3-kinase inhibitor), Akt inhibitor, staurosporine (PKC inhibitor), PD 98059 (MEK inhibitor), SB 203580 (p38 MAPK inhibitor), or SP 600125 (JNK inhibitor) blocked 30 mM glucose-induced AQP8 translocation, respectively. In addition, inhibition of microtubule movement with nocodazole blocked high glucose-induced AQP8 translocation. High glucose level also increased the level of kinesin light chain and dynein protein expression. In conclusion, high glucose level stimulates AQP8 via cAMP, PI3-K/Akt, PKC, and MAPKs pathways in primary cultured chicken hepatocytes.
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PMID:High glucose induced translocation of Aquaporin8 to chicken hepatocyte plasma membrane: involvement of cAMP, PI3K/Akt, PKC, MAPKs, and microtubule. 1766 57


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