Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0043167 (pertussis)
 19,595 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

In solubilized bovine brain membrane preparations AlF4- (20 microM AlCl3 plus 10 mM NaF) and 50 nM guanosine 5-O-(2-thiotriphosphate) (GTP gamma S) promoted a rapid but transient inhibition of phospholipase C (PLC) activity. Maximal inhibition was evident within 7 min of incubation, followed by reversal of inhibition. In contrast, 10 microM GTP gamma S did not induce inhibition of PLC activity but rather produced a time-dependent stimulation of PLC activity. GTP gamma S-dependent inhibition of PLC activity was concentration-dependent with half-maximal inhibition at 1 nM. Inhibition was antagonized by guanosine 5-O-(2-thiodiphosphate (GDP beta S). Pertussis toxin delayed the onset of inhibition by GTP gamma S but did not prevent the inhibitory effect. alpha o-GTP gamma S or alpha o-GDP had little effect on PLC activity. alpha i-GTP gamma S and alpha i-GDP produced a 15% inhibition of PLC activity. Beta gamma subunits did not inhibit basal PLC activity but did attenuate the net degree of inhibition due to GTP gamma S. Inhibition was associated with a decrease in the Ca2+ sensitivity of PLC. Preincubation of membranes with anti-PLC-beta 1 antibody, but not anti-PLC-gamma 1 or anti-PLC-delta 1, prevented the GTP gamma S-mediated inhibition of PLC. These studies implicate PLC-beta 1 as an effector system that is under negative modulation by a G protein-dependent mechanism.
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PMID:G protein-mediated inhibition of phospholipase C activity in a solubilized membrane preparation. 847 13

Corticosteroid regulation of Na/K-ATPase is of key importance in the modulation of Na+ transport across renal tubular epithelia. In amphibian renal cells, aldosterone induction of Na/K-ATPase alpha 1 and beta 1 subunit gene transcription is mediated by an indirect mechanism dependent on the synthesis of a labile protein. In mammalian target cells, while both mineralo- and glucocorticoids increase the levels of Na/K-ATPase alpha 1 and beta 1 subunit mRNA and enzyme activity, they are diminished by glycyrrhetinic acid (GE), the active ingredient of licorice. To investigate the mechanisms underlying the regulation of mammalian renal Na/K-ATPase, levels of alpha 1 and beta 1 mRNA were measured in rat kidney epithelial (NRK-52E) cells treated with a range of concentrations of aldosterone, corticosterone and GE in the presence of a specific inhibitor of mRNA synthesis, dichlororibofuranosylbenzimidazole (DRB), an inhibitor of total RNA synthesis, actinomycin D (ActD), and the protein synthesis inhibitor cycloheximide (CHX). In addition, GE was co-incubated with the sodium channel antagonist benzamiloride (BZ). The increase in both alpha 1 and beta 1 mRNA levels following aldosterone and corticosterone was completely abolished by treatment with ActD and DRB, while CHX did not affect this response. Similarly, the GE-induced decrease in alpha 1 and beta 1 mRNA was also completely abolished by ActD and DRB, but not by CHX or by BZ. The half-lives of alpha 1 and beta 1 mRNA in these cells (means +/- S.E.M., n = 4), estimated from the rate of mRNA decay in the presence of DRB, were 6.8 +/- 0.3 and 4.8 +/- 0.2 h respectively. This was unaffected by GE. The inhibitory action of GE on alpha 1 and beta 1 mRNA levels was accompanied by a dose-dependent decrease in levels of intracellular cAMP (means +/- S.E.M., n = 4) from 395 +/- 28 fmol cAMP/microgram total cell protein to between 275 +/- 19 fmol/micrograms total cell protein (0.1 microM GE) and 78 +/- 11 fmol/micrograms total cell protein (10 microM GE). This was abolished following down-regulation of protein kinase C by prolonged treatment with the phorbol ester tetradecanoylphorbol-13-acetate (TPA), and by pertussis toxin (PT), but not by cholera toxin (CT). Indeed, subunit mRNA levels were increased by 8-bromo-cAMP (2.2-fold) and stimulators of adenylate cyclase activity, i.e. forskolin (2.1-fold), PT (2.1-fold) and CT (1.9-fold), but not by TPA.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Transcriptional regulation of Na/K-ATPase by corticosteroids, glycyrrhetinic acid and second messenger pathways in rat kidney epithelial cells. 854 17

Protein phosphorylation was investigated in [32P]-labeled cardiomyocytes isolated from adult rat heart ventricles. The beta-adrenergic stimulation (by isoproterenol, ISO) increased the phosphorylation of inhibitory subunit of troponin (TN-I), C-protein and phospholamban (PLN). Such stimulation was largely mediated by increased adenylyl cyclase (AC) activity, increased myoplasmic cyclic AMP and increased cyclic AMP dependent protein kinase (A-kinase)-catalyzed phosphorylation of these proteins in view of the following observations: (a) dibutyryl-and bromo-derivatives of cyclic AMP mimicked the stimulatory effect of ISO on protein phosphorylation while (b) Rp-cyclic AMP was found to attenuate ISO-dependent stimulation. Unexpectedly, 8-bromo cyclic GMP was found to markedly increase TN-I and PLN phosphorylation. Both beta 1- and beta 2-adrenoceptors were present and ISO binding to either receptor was found to stimulate myocyte AC. However, the stimulation of the beta 2-AR only marginally increased while the stimulation of beta 1-AR markedly increased PLN phosphorylation. Other stimuli that increase tissue cyclic AMP levels also increased PLN and TN-I phosphorylation and these included isobutylmethylxanthine (non-specific phosphodiesterase inhibitor), milrinone (inhibits cardiotonic inhibitable phosphodiesterase, sometimes called type III or IV) and forskolin (which directly stimulates adenylyl cyclase). Cholinergic agonists acting on cardiomyocyte M2-muscarinic receptors that are coupled to AC via pertussis toxin(PT)-sensitive G proteins inhibited AC and attenuated ISO-dependent increases in PLN and TN-I phosphorylation. The in vivo PT treatment, which ADP-ribosylated Gi-like protein(s) in the myocytes, markedly attenuated muscarinic inhibitory effect on PLN and TN-I phosphorylation on one hand and, increased the beta-adrenergic stimulation, on the other. Controlled exposure of isolated myocytes to N-ethyl maleimide, also led to the findings similar to those seen following the PT treatment. Exposure of myocytes to phorbol, 12-myristate, 13-acetate (PMA) increased the protein phosphorylation, augmenting the stimulation by ISO, and such augmentation was antagonized by propranolol suggesting modulation of the beta-adrenoceptor coupled AC pathway by PMA. Okadaic acid (OA) exposure of myocytes also increased protein phosphorylation with the results supporting the roles for type 1 and 2A protein phosphatases in the dephosphorylation of PLN and TN-I. Interestingly OA treatment attenuated the muscarinic inhibitory effect which was restored by subsequent brief exposure of myocytes to PMA. While the stimulation of alpha adrenoceptors exerted little effect on the phosphorylation of PLN and TN-I, inactivation of alpha adrenoceptors by chloroethylclonidine (CEC), augmented beta-adrenergically stimulated phosphorylation. KCl-dependent depolarization of myocytes was observed to potentiate ISO-dependent increase in phosphorylation (incubation period 15 sec to 1 min) as well as to accelerate the time-dependent decline in this phosphorylation seen upon longer incubation. Verapamil decreased ISO-stimulated protein phosphorylation in the depolarized myocytes. Depolarization was found to have little effect on the muscarinic inhibitory action on phosphorylation. Prior treatment of myocytes with PMA, was found to augment ISO-stimulated protein phosphorylation in the depolarized myocytes. Such augmented increases were completely blocked by propranolol. Forskolin also stimulated PLN and TN-I phosphorylation. Prior exposure of myocytes to forskolin followed by incubation in the depolarized and polarized media showed that PLN was dephosphorylated more rapidly in the depolarized myocytes. The results support the view that both cyclic AMP and calcium signals cooperatively increase the rates of phosphorylation of TN-I and PLN in the depolarized cardiomyocytes during beta-adrenergic stimulation. (ABSTRACT TRUNCATED)
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PMID:Regulation of phospholamban and troponin-I phosphorylation in the intact rat cardiomyocytes by adrenergic and cholinergic stimuli: roles of cyclic nucleotides, calcium, protein kinases and phosphatases and depolarization. 856 20

+/- -Higenamine (demethylcoclaurine), a cardiotonic principle from aconite root, chronotropic and inotropic actions mediated through beta 1-adrenergic receptors. We have investigated the influence of cholera toxin (CTX), a Gs-protein activator, and pertussis toxin (PTX), a Gi-protein inhibitor on the chronotropic interaction between higenamine and a muscarinic agonist, acetylcholine (ACh) in the isolated right atria of mice. CTX (100nm, 1h) pretreatment accentuated the inhibitory responses to cumulative applications of ACh (30nM--30 microns for the positive chronotropic effects induced by higenamine (100nM), isoproterenol (3 and 10 nM) or dobutamine (100nM). In normal atria (CTX-untreated), ACh physiologically antagonized the positive chronotropic effects of these beta-adrenergic agonists. Pretreatment with PTX (150 microgram/kg, i.p., 3d) abolished the CTX (100nm, 1 h)-induced accentuation in the inhibitory effect of ACh against higenamine. PTX pretreatment also attenuated the physiological antagonism by ACh against higenamine in normal atria. The negative chronotropic effect of ACh was not affected by a submaximal concentration of forskolin (1 micron). The These results suggest an accentuated antagonism between higenamine and ACH in CTX-treated, but not in untreated, isolated right atria of mice, which may occur through a functional interaction between the beta1-adrenergic-Gs and muscarinic-Gi systems.
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PMID:Cholera toxin accentuates the antagonism by acetylcholine of higenamine-induced positive chronotropy is isolated right atria of mice. 859 68

The gamma subunit of heterotrimeric G proteins is isoprenylated and methylated on its carboxyl terminal cysteine residue. While retinal transducin is farnesylated, all other gamma subunits are modified by geranylgeranylation. An immobilized form of pig liver esterase (iPLE) is able to hydrolyze the methyl ester of a geranylgeranylated beta gamma isoform (beta 1 gamma 2). Since methylation is the only reversible reaction in the isoprenylation pathway, it could be a site of regulation of G protein activity. With both the methylated and demethylated beta 1 gamma 2 now available, the role of methylation for a geranylgeranylated heterotrimeric G protein may be addressed. Here, it is reported that methylation has no effect on the ability of beta gamma to interact with an alpha subunit, as probed by ADP-ribosylation studies with pertussis toxin, and has a small effect (less than 2-fold) on the ability of geranylgeranylated beta gamma to activate phosphatidylinositol-specific phospholipase C (PIPLC) and phosphoinositide 3 kinase (PI3K). In binding studies, demethylation only slightly decreased the ability of beta 1 gamma 2 to adhere to azolectin vesicles. Therefore, methylation of heterotrimeric G proteins appears to have only a minor effect in signal transduction processes which can be correlated to a decrease in hydrophobicity of the beta gamma subunit.
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PMID:The role of G protein methylation in the function of a geranylgeranylated beta gamma isoform. 865 28

The introduction of D1A dopamine receptors and mu-opioid receptors into HEK 293 cells that were also transiently transfected with adenylyl cyclase cDNA imparted to dopamine and to mu-opioid receptor agonists the ability to modulate the activity of the expressed adenylyl cyclase. Dopamine added to cells expressing D1A receptors and type V adenylyl cyclase significantly stimulated type V enzyme activity. The concomitant addition of morphine produced a dose-dependent inhibition of dopamine-stimulated type V adenylyl cyclase activity. On the other hand, if the HEK 293 cells were transfected with cDNA for type VII adenylyl cyclase instead of the type V isoform, morphine stimulated this adenylyl cyclase activity beyond the stimulation produced by dopamine. Both the inhibitory and stimulatory effects of morphine were blocked by naloxone or pretreatment of the transfected HEK 293 cells with pertussis toxin. When expressed in the HEK 293 cells, the alpha subunit of transducin, which is considered to be the putative scavenger of the beta gamma subunits of G proteins, suppressed the stimulatory effect of morphine on type VII adenylyl cyclase. We also expressed the adenylyl cyclases in cells that were transfected with D1A receptor and G beta 1 and G gamma 2 cDNAs. Dopamine was more efficacious in stimulating type VII adenylyl cyclase activity in cells concomitantly transfected with the beta gamma subunit cDNAs than in cells not transfected with these G protein subunits. Transfection with beta gamma subunit cDNAs did not affect dopamine stimulation of type V adenylyl cyclase activity, and morphine-induced inhibition of type V adenylyl cyclase activity was still evident in cells cotransfected with the alpha subunit of transducin. These data support the contention that the effects on type VII adenylyl cyclase activity mediated through the G1/G(o) proteins may depend on the actions of the beta gamma subunits. The same is not the case for type V adenylyl cyclase. Our data demonstrate that both qualitative and quantitative responses to mu-opioid receptor stimulation depend on the isoform of adenylyl cyclase expressed in neurons or other cells of the body.
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PMID:mu-Opioid receptors inhibit dopamine-stimulated activity of type V adenylyl cyclase but enhance dopamine-stimulated activity of type VII adenylyl cyclase. 870 Jan 17

In view of the lack of information regarding the status of beta-adrenoceptor mediated signal transduction mechanisms at severe stages of congestive heart failure, the status of beta-adrenoceptors, G-proteins and adenylyl cyclase activities was examined in 220-275 day old cardiomyopathic hamster hearts. Although no changes in the Kd values for beta 1- and beta 2-adrenoceptors were seen, the number of beta 1-adrenoceptors, unlike that of beta 2-adrenoceptors, was markedly decreased in cardiac membranes from failing hearts. The activation of adenylyl cyclase in the failing hearts by different concentrations of isoproterenol was also attenuated in comparison to the control preparations. The basal adenylyl cyclase activity in cardiac membranes from the failing hearts was not altered; however, the stimulated enzyme activities, when measured in the presence of forskolin, NaF or Gpp(NH)p were depressed significantly. The functional activity of Gs-proteins (measured by cholera toxin stimulation of adenylyl cyclase) was depressed whereas that of Gi-proteins (measured by pertussis toxin stimulation of adenylyl cyclase) was increased in the failing hearts. Not only were the Gs- and Gi-protein contents (measured by immunoblotting) increased, the bioactivities of these proteins as determined by ADP-ribosylations in the presence of cholera toxin and pertussis toxin, respectively, were also higher in failing hearts in comparison to the control values. Northern blot analysis revealed that the signals for Gs- and Gi-protein mRNAs were augmented at this stage of heart failure. These results indicate that the loss of adrenergic support at severe stages of congestive heart failure in cardiomyopathic hamsters may involve a reduction in the number of beta 1-adrenoceptors, and an increase in Gi-protein contents as well as bioactivities in addition to an uncoupling of Gs-proteins from the catalytic site of adenylyl cyclase in cardiac membrane.
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PMID:Beta-adrenoceptor mediated signal transduction in congestive heart failure in cardiomyopathic (UM-X7.1) hamsters. 873 46

Bombesin stimulation of inositol 1,4,5-trisphosphate (Ins P3) formation in rat sonicated pancreatic acinar cells was inhibited by an antibody directed against the pertussis toxin (PTX)-sensitive GTP-binding G alpha i3 protein but not by an anti-G alpha q-11 antibody. After solubilization and gel filtration, [125I-Tyr4]bombesin binding sites were recovered in a peak of protein of 67 approximately 90 kDa with a maximal enrichment corresponding to a molecular mass of 83-kDa. Results obtained from the non-hydrolysable GTP analog guanosine-5'-[gamma-thio]triphosphate (GTP gamma S) binding, PTX-stimulated ADP-ribosylation and immunoblotting showed that the 83-kDa fraction contained the G alpha i3 protein but not the G alpha q-11 protein. Furthermore, GTP gamma S increased the bombesin binding dissociation constant (KD) from 0.32 to 0.60 nM, while the anti-G alpha i3 antibody decreased the maximal binding capacity (Bmax) from 50 to 25 fmol/mg protein without affecting the KD. Mixing solubilized bombesin binding sites with a phospholipase C (PLC) preparation from rat pancreas reconstituted a bombesin-stimulated PLC activity which was markedly inhibited by the anti-G alpha i3 antibody but unaffected by the anti-G alpha q-11 antibody. In addition, this stimulation was inhibited by an anti-PLC beta 1 antibody. This result supports the involvement of the PLC beta 1 isoform in bombesin receptor activation.
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PMID:Bombesin activation of phospholipase C beta 1 in rat acinar pancreatic cells involves the pertussis toxin-sensitive G alpha i3 protein. 879 79

1. We sought to reconstitute and characterize G-protein linked phosphatidyl-D-inositol 4,5-bisphosphate (PIP2)-directed phospholipase C (PLC) isoform activity in pig aortic vascular smooth muscle. 2. Six soluble PLC isoforms, namely gamma 1, delta 1 and beta 1 to beta 4 were partially separated by heparin affinity chromatography and were identified by Western blotting using specific antibodies. 3. In separate experiments, PLC activity was measured in the eluted fractions. Four of the partially resolved PLC isoforms gamma 1, beta 4, beta 2 and beta 1, showed corresponding activity using exogenous [3H]-PIP2 as substrate. 4. The isolated soluble PLC isoforms were reconstituted with receptors and guanyl nucleotide regulatory proteins (G-proteins) by addition of plasma membranes, the phospholipids which had been prelabelled with [3H]-myo-inositol. When so reconstituted PLC beta 2, beta 3 and beta 4 were inhibited (40 +/- 9, 47 +/- 12 and 40 +/- 5% respectively n = 12, +/-s.e.mean and each P < 0.05) by the addition of 1 mM guanosine 5'[beta gamma-imido]triphosphate (p[NH]ppG). 5. By contrast, when plasma membranes were preincubated with pertussis toxin to inhibit the activity of G-protein subunits G alpha i/alpha o the activities of PLC beta 2, beta 3 and beta 4 were stimulated (46 +/- 11, 31 +/- 9 and 37 +/- 8% respectively, n = 12, +/- s.e.mean and each P < 0.05) by the addition of p[NH]ppG. 6. Using well resolved fractions containing only PLC beta 3, time-dependent activity in the presence of p[NH]ppG was measurable only with membranes pretreated with pertussis toxin. 7. PLC beta 3 activity, measured with pertussis pretreated membranes, showed a dose-dependent increase in the presence of p[NH]ppG or guanosine 5'-[gamma-thio]triphosphate (GTP[S]). This increase with 10 microM p[NH]ppG or GTP[S] 10% +/- 4 and 12% +/- 5 respectively (both P < 0.05 vs control without GTP analogue +/- s.e.mean, n = 10) was abolished by 50 microM guanosine 5'-[beta-thio]diphosphate (GDP[S]) which also reduced constitutive PLC beta 3 activity by 9% +/- 4. 8. G-protein antibodies were used to neutralize PLC activity. Antibody to G alpha q/alpha 11, added to membrane fractions pretreated with pertussis toxin and assayed with GTP[S], reduced PLC beta 3 activity by 21% +/- 6 P < 0.02, n = 6, but was without effect on non-pertussis pretreated membranes. Antibodies to G alpha i1/alpha i2 had no effect. Antibodies to G-protein beta subunits had no effect on PLC beta 3 activity with pertussis pretreated preparations but activity without pertussis pretreatment was increased by 30% +/- 10, P < 0.03, n = 6. All results were expressed as % change from controls containing rabbit IgG. 9. In conclusion, pig aortic vascular smooth muscle contains six PLC isoforms. Activation of pertussis sensitive G-protein by GTP analogues results in inhibition of PLC beta 3 activity from liberated G-protein beta gamma subunits. Stimulation of PLC beta 3 activity is associated with a G-protein of the G alpha q family acting through the alpha subunit. The results suggest that the G-protein linked PLC beta isoforms in vascular smooth muscle demonstrate dual regulation by an inhibitory pertussis-sensitive pathway and a stimulatory G-protein of the G alpha q family, which is the case for PLC beta 3. This dual regulation is analogous to that of adenyl cyclase.
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PMID:Phospholipase C isoforms in vascular smooth muscle and their regulation by G-proteins. 879 75

The mechanism(s) whereby hepatocytes restore denuded areas remains unknown. We therefore studied the recovery of denuded areas made in monolayers of primary cultures of rat hepatocytes. Minimal recovery occurred in cells plated on plastic. Plating on Matrigel produced modest recovery (25% at 24 h), whereas plating on a type I collagen substrate resulted in > 70% recovery at 24 h. The rate of recovery on collagen could be attenuated by a monoclonal antibody directed against the extracellular domain of the beta 1-integrin subunit. Monoclonal antibodies directed against CD44 (the hyaluron receptor) and E-cadherin did not influence the rate of recovery. Recovery could be stimulated, in a dose-dependent fashion, by epidermal and hepatocyte growth factors. The effects of epidermal and hepatocyte growth factors to promote recovery occurred in the absence of 5-bromo-2'-deoxyuridine uptake, suggesting a proliferation-independent mechanism. Transforming growth factor-beta 1 inhibited recovery. Exposure to selected cytokines (interleukins 1 and 2), an adenine nucleotide [adenosine 5'-O-(3-thiotriphosphate)], adenosine, pertussis toxin, and selected agents that bind to fibronectin and other matrix component adhesive sites (heparin and the RGD peptide) did not influence the rate of recovery of hepatocytes. However, the peptide DGEA, which can bind to collagen adhesive sites, attenuated recovery. These studies demonstrate that primary cultures of rat hepatocytes require a particular type of extracellular matrix to renew denuded areas and that the beta 1-integrin subunit may be involved in this recovery process. Hepatocyte recovery of denuded areas can be modulated by growth factors in both a stimulatory (epidermal and hepatocyte growth factors) and an inhibitory (transforming growth factor-beta 1) fashion.
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PMID:Mechanisms of recovery from mechanical injury of cultured rat hepatocytes. 884


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