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

A number of different protein kinases phosphorylate purified heavy chains or the 20-kDa light chain of smooth muscle myosin. The physiological significance of these phosphorylation reactions has been examined in intact smooth muscle. Myosin heavy chain was slightly phosphorylated (0.08 mol of phosphate/mol) under control conditions in bovine tracheal tissue. Treatment with carbachol, isoproterenol, or phorbol 12,13-dibutyrate resulted in no significant change. In contrast, heavy chain was phosphorylated to 0.30 mol of phosphate/mol of heavy chain in tracheal smooth muscle cells in culture. This value increased significantly with ionomycin treatment. In control tissues, 9% of the light chain was monophosphorylated with 32P in the serine site phosphorylated by myosin light chain kinase. Carbachol (0.1 microM) alone resulted in contraction and 42% monophosphorylated light chain with 32P only in the serine site phosphorylated by myosin light chain kinase. Similarly, stimulation with histamine, 5-hydroxytryptamine, or KCl resulted in 32P incorporation into only the myosin light chain kinase serine site. Phorbol 12,13-dibutyrate (1 microM) alone resulted in 22% monophosphorylated light chain. However, only 25% of the 32P was in the myosin light chain kinase serine site, whereas 75% was in a serine site phosphorylated by protein kinase C. Phorbol 12,13-dibutyrate plus carbachol resulted in 27% monophosphorylated light chain; 75% of the 32P was in the myosin light chain kinase serine site, with the remainder in the protein kinase C serine site. These results indicate that phorbol esters act to increase phosphorylation of myosin light chain by protein kinase C. However, receptor-mediated stimulation or depolarization leading to tracheal smooth muscle contraction results in phosphorylation of myosin light chain by myosin light chain kinase alone.
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PMID:Phosphorylation of smooth muscle myosin heavy and light chains. Effects of phorbol dibutyrate and agonists. 259 71

1. We studied effects of the phorbol ester, phorbol 12,13-dibutyrate (PDB), on carbachol-induced contractions of swine trachealis muscle. PDB (1-10 microM) markedly inhibited 5.5 microM-carbachol-induced inositol phosphate synthesis allowing us to study (a) whether the membrane potential-independent component of force (pharmacomechanical coupling component) developed in carbachol-stimulated trachealis muscle is dependent on activation of inositol phospholipid metabolism, and (b) whether carbachol-induced membrane depolarization and contraction are altered in muscle where second messenger signals generated by inositol phospholipid metabolism are inhibited and activation of protein kinase C (PKC) is already maximal. 2. Application of PDB (10 microM) to unstimulated trachealis muscle resulted in a small slowly developing contraction associated with a 10 m V membrane depolarization. PDB-evoked contractions were not influenced by Na+ or Cl- ion substitutions, or administration of amiloride, all of which inhibited PDB-evoked membrane depolarization. 3. Pre-treatment with PDB had no effect on [K+]-force, or [K+]-membrane potential relationships, over a range of extracellular [K+] from 40 to 70 mM. Pretreatment with PDB had no effect on extracellular [Ca2+]-force relationships during 40 mM-K+. 4. Carbachol-evoked contractions of muscle treated with PDB became similar to K+ contractions in regard to effects of organic Ca2+ antagonist drugs or decrease in bathing solution [Ca2+]. At low carbachol concentrations, verapamil plus PDB completely inhibited force development. With 5.5 microM-carbachol, over 90% of total carbachol-induced force was inhibited by verapamil, or nifedipine, plus PDB. 5. Control carbachol-evoked contractions were associated with 20-25 mV membrane depolarizations. In PDB-treated muscle, carbachol-evoked contraction occurred with a blunted depolarization, i.e. about 5 mV. 6. Force controlled by pharmacomechanical coupling mechanisms operating during maintained carbachol-evoked contractions was inhibited by treatment with PDB. Carbachol-induced force dependent on pharmacomechanical coupling mechanisms could be explained by signals generated via inositol phospholipid metabolism. 7. Electromechanical coupling mechanisms were augmented during carbachol in PDB-treated muscle. This appears to be due primarily to changes in the properties or number of surface membrane voltage-gated Ca2+ channels. 8. Data suggest an important role of PKC-mediated phosphorylations for control of both pharmacomechanical coupling mechanisms mediated by activation of inositol phospholipid metabolism and electromechanical coupling mechanisms mediated by effects on operation of surface membrane ion channels.
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PMID:Phorbol ester effects on coupling mechanisms during cholinergic contraction of swine tracheal smooth muscle. 260 Aug 31

1. Mouse atria were incubated with [3H]-noradrenaline, and the outflow of radioactivity due to electrical field stimulation (5 Hz, 60 s) was used as an index of noradrenaline release. Angiotensin II (0.01 and 0.1 microM) significantly enhanced the stimulation-induced (S-I) outflow of radioactivity. 2. Phorbol 12-myristate 13-acetate (0.001, 0.03, 0.1 and 1.0 microM), a protein kinase C activating phorbol ester, significantly enhanced the S-I outflow of radioactivity. When angiotensin II (0.1 microM) was present with the concentration of phorbol 12-myristate 13-acetate that was maximally effective in increasing the S-I outflow (0.1 microM), the enhancement of S-I outflow produced by angiotensin II was maintained. 3. Polymyxin B (70 microM), an inhibitor of protein kinase C, significantly inhibited the S-I outflow. Polymyxin B also inhibited the enhancement of the S-I outflow produced by angiotensin II (0.1 microM). 4. In another series of experiments mice were injected with pertussis toxin (1.5 micrograms per mouse), 4 days before their atria were removed. The effectiveness of pertussis toxin pretreatment was determined indirectly using carbachol. Carbachol caused a concentration-dependent fall in both the rate and force of beating of isolated spontaneously beating atria from mice pretreated with vehicle. This effect of carbachol was not seen with atria from mice pretreated with pertussis toxin. 5. Pertussis toxin pretreatment did not alter the enhancement of the S-I outflow of radioactivity produced by angiotensin II (0.01 and 0.1 microM). 6. These results suggest that angiotensin II receptor modulation of noradrenaline release is not mediated through either a pertussis toxin sensitive guanine nucleotide-binding protein or activation of protein kinase C.
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PMID:Effect of phorbol ester and pertussis toxin on the enhancement of noradrenaline release by angiotensin II in mouse atria. 272 Feb 95

We undertook these studies to examine the mechanisms by which carbachol inhibits somatostatin release. For these studies, we utilized cultured D-cells isolated from the canine gastric fundus. Carbachol inhibited somatostatin release induced by both pentagastrin and 12-O-tetradecanoyl-phorbol-13-acetate but did not alter the redistribution of protein kinase C induced by these agents. In contrast, carbachol diminished the increase in D-cell cytosolic free calcium levels ([Ca2+]i) induced by pentagastrin, and this effect was no longer evident after pretreatment of D-cells with pertussis toxin. Although carbachol by itself had no effect on [Ca2+]i, after pretreatment of D-cells with pertussis toxin, carbachol both enhanced [Ca2+]i and stimulated somatostatin release. These data indicate that carbachol activates signals in D-cells that result in both increase and decrease in [Ca2+]i. The latter effect, which appears to be mediated via a pertussis toxin-sensitive guanine nucleotide binding protein, may be one mechanism responsible for cholinergic inhibition of somatostatin release.
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PMID:Carbachol inhibits stimulant-induced increases in fundic D-cell cytosolic Ca2+ concentration. 276 14

The role of G proteins and protein kinase C in mediating muscarine receptor-linked prostanoid synthesis by the rat urinary bladder was investigated using the G protein activator, sodium fluoride (NaF); the protein kinase C activators, phorbol myristate (PMA) and phorbol dibutyrate (PDBU); the protein kinase C inhibitor, H7, and the parasympathomimetic, carbachol. NaF stimulated in vitro rat urinary bladder prostacyclin (PGI2) synthesis (EC50 = 6 mmol.l-1), an action inhibited by the presence of EDTA (10 mmol.l-1). Carbachol potentiated the stimulatory action of NaF. NaF (10 mmol.l-1)-stimulated PGI2 synthesis was inhibited by the calcium channel blockers verapamil, nifedipine and the protein kinase C inhibitor, H7, in concentration-dependent manners. Carbachol-stimulated PGI2 synthesis was also inhibited by H7. PDBU and PMA were without effect on de novo, NaF- or carbachol-stimulated urinary bladder PGI2 synthesis. Other prostanoids (PGF2 and PGF2 alpha) were stimulated to the ame degree as PGI2 by NaF, and inhibited equally by H7 and calcium channel blockers. Dibutyryl adenosine 3':5'-cyclic monophosphate was without effect on de novo or NaF-stimulated prostanoid synthesis. Since fluoride activates G proteins, these data indicate that: (1) muscarine receptor-prostanoid synthesis coupling is mediated by G proteins in the rat urinary bladder; (2) fluoride action is mediated by protein kinase C and not adenyl cyclase, probably through activation of phospholipase C and therefore the generation of the protein kinase C activator, diacyl glycerol; (3) activated protein kinase C may initiate Ca2++ mobilisation linked to prostanoid synthesis; and (4) the lack of effect of the phorbol esters on urinary bladder PGI2 synthesis, in contrast to that on other smooth muscle, indicates that in different smooth muscle tissues there are varying forms of protein kinase C.
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PMID:Fluoride but not phorbol esters stimulate rat urinary bladder prostanoid synthesis: investigations into the roles of G proteins and protein kinase C. 282 37

The protein kinase C activator 4 beta-phorbol 12,13-dibutyrate (PDB) enhanced the electrically stimulated release of radiolabelled noradrenaline (NA), acetylcholine (ACh) and 5-hydroxytryptamine (5-HT) from dorsal hippocampal slices of the rat in vitro in a concentration-dependent manner. 4 alpha-Phorbol 12,13 didecanoate did not have an effect on the electrically stimulated release of any of the neuromessengers. Carbachol, which when present in the superfusion medium alone inhibited [14C]ACh release, significantly reduced the effect of PDB on the release of this neuromessenger. In the presence of either clonidine or [Leu5]enkephalin, which by themselves inhibited the electrically stimulated release of [3H]NA, the effect of PDB was significantly reduced. The enhancing effects of yohimbine and PDB on the electrically stimulated release of [3H]NA were additive. In all three cases, thus, the net effects of PDB were of a similar magnitude, whether the various compounds were present or not. Taken together, the present data suggest that the diacylglycerol/protein kinase C pathway is involved in the stimulus-evoked release of NA, ACh and 5-HT from dorsal hippocampal nerve terminals. Protein kinase C seems not to be involved in the modulation of the release of NA via presynaptic alpha 2-adrenoceptors and delta-opioid receptors and in that of ACh via presynaptic ACh receptors in that brain region.
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PMID:Phorbol 12,13-dibutyrate enhances electrically stimulated neuromessenger release from rat dorsal hippocampal slices in vitro. 288 98

Carbachol (CCh), a muscarinic agonist that elicits the formation of inositol trisphosphate (IP3) and diacylglycerol (DG), induces a calcium-dependent [3H]norepinephrine ([3H]NE) release [IC50 = (2.7 +/- 0.5) X 10(-4) M] in rat brain slices. Similarly, other muscarinic agonists evoke [3H]NE release which is specifically inhibited by muscarinic antagonists such as 3-quinuclidinyl benzilate, atropine, and N-methyl-4-piperidyl benzilate. The atropine-sensitive evoked release is effectively inhibited by neomycin (IC50 = 50 microM), a phospholipase C inhibitor that interferes with IP3-dependent cellular processes. In addition, polymyxin B, a rather selective inhibitor of protein kinase C (PK-C), abolishes the agonist-mediated release with a half-maximal effective concentration of 0.53 microM (750 ng/ml). These results have a significant implication for the mechanism by which agonists generating IP3 and DG act as inducers of neurotransmitter release in the CNS. However, since both neomycin and polymyxin B act also as N-calcium-channel blockers, other possible mechanisms are discussed. The CCh-induced release suggests that in the CNS an agonist-receptor interaction leads to a calcium-dependent neurotransmitter release, most likely via promoting the IP3/DG as second messengers followed by activation of PK-C.
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PMID:Muscarinic agonists evoke neurotransmitter release: possible roles for phosphatidyl inositol bisphosphate breakdown products in neuromodulation. 290 Aug 76

Development of an enriched cultured cell system allowed us to investigate the mechanism of cholinergic inhibition of somatostatin release stimulated by adenosine 3',5'-cyclic monophosphate (cAMP) and Ca2+-protein kinase C-dependent pathways of cell activation. After a 24-h culture on rat tail collagen, D-cells, quantified by immunohistochemistry, were 18-fold enriched compared with unelutriated dispersed cells. Somatostatin release from cultured cells was expressed as a percent of the somatostatin released by a specific stimulus in control cells. Under basal conditions release of somatostatin was 2.3 +/- 0.6% of the total cell content. Epinephrine (1 microM) and cholecystokinin octapeptide (10 nM) increased somatostatin release to 6.98 +/- 1.25 and 10.72 +/- 1.64%, respectively. Carbachol (1 microM) completely inhibited somatostatin release stimulated by epinephrine and reduced cholecystokinin octapeptide-stimulated release to 75% of control levels. Carbachol inhibition of the response to both epinephrine and cholecystokinin octapeptide was totally prevented by 5 h of treatment of the cells with pertussis toxin (300 ng/ml). Somatostatin release in response to the diterpene forskolin (10 microM), dibutyryl cAMP (300 microM), the phorbol ester beta-phorbol 12-myristate 13-acetate (0.1 microM), and the calcium ionophore A23187 (1 microM) was also inhibited by carbachol and prevented by pertussis toxin pretreatment. The ADP-ribosylase inhibitor isonicotinamide (1 mM) selectively blocked the effect of pertussis toxin without altering other stimulatory or inhibitory responses. These data are consistent with the view that carbachol inhibits somatostatin release at guanyl nucleotide-binding protein and/or another pertussis toxin-sensitive site.
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PMID:Pertussis toxin-sensitive cholinergic inhibition of somatostatin release from canine D-cells. 290 2

The hydro-osmotic response of the toad urinary bladder to antidiuretic hormone (ADH) and cyclic AMP was inhibited by phorbol myristate acetate (PMA) and 4 beta- phorbol dideconate (4 beta-PDD), activators of protein kinase C (PKC). The inactive epimer of 4 beta-PDD, had no effect on the ADH response. The osmotic transfer of water in the absence of ADH was unaffected by PMA. PKC activity, localized in the soluble fraction of isolated toad bladder cells, was activated by PMA. ADH initially inhibited and subsequently stimulated 32Pi incorporation into phosphatidic acid (PA) and phosphatidylinositol (PI). Carbachol, which inhibits ADH-induced water flow, also stimulated 32P incorporation into PA and PI. It is suggested that phosphoinositide breakdown to diacylglycerol may activate PKC which functions to attenuate the hormone-mediated permeability response.
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PMID:Calcium/phospholipid-dependent protein kinase and its relationship to antidiuretic hormone in toad urinary bladder epithelium. 300 55

We have examined the effect of secretagogues on cytosolic free Ca2+ (Cai) in the hamster clonal beta-cell line HIT-T15 using the Ca2+-binding fluorescent indicator Quin 2. Stimulation of HIT cells by glucose increased Cai in a dose-dependent manner; raising the medium glucose concentration from zero to 2 mM increased Cai by 36%, from 89 +/- 4 to 121 +/- 6 nM (mean +/- S.E.M., n = 23). Further raising the medium glucose concentration to 10 mM increased Cai to 139 +/- 6 nM. Cai was maximum and plateaued at 4 min after each addition of glucose. Addition of 40 mM K+ to the medium rapidly depolarized the HIT cells and increased Cai to 407 +/- 48 nM. The increases in Cai in response to glucose of K+ were blocked by the simultaneous presence of verapamil (50 microM). Stimulation by glucose or K+ also increased insulin release in parallel incubations of Quin 2-loaded HIT cells. Carbamylcholine chloride, forskolin or the phorbol ester 12-O-tetradecanoylphorbol acetate had no significant effect on Cai in glucose-stimulated HIT cells monitored 5 min after the addition of each test agent, despite increasing insulin release by 241, 239 and 216% respectively. These data support the hypothesis that potentiators of insulin release which activate cAMP-dependent protein kinase or protein kinase C do not increase Cai but sensitize the secretory mechanism to Ca2+.
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PMID:Effect of secretagogues on cytosolic free Ca2+ and insulin release in the hamster clonal beta-cell line HIT-T15. 307 76


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