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)

Leukotriene C4 (LTC4) is known to be a potent mitogen for cultured human neonatal melanocytes. We now demonstrate that leukotriene B4 (LTB4) can induce pigmentation in cultured human neonatal melanocytes in a dose-dependent fashion. The LTC4-induced mitogenesis is blocked by the cyclic nucleotide-dependent kinase inhibitor N-[2-(methyl-amino)ethyl]-5-isoquinolinesulfonamide dihydrochloride (H8). The LTB4-induced pigmentation is blocked by the protein kinase C inhibitor 1-(5-isoquinolinesulfonyl)-2-methylpiperazine dihydrochloride (H7). We propose that LTB4-induced pigmentation and LTC4-induced mitogenesis are important in vivo signals. Their different effects in our culture system are blocked by different protein kinase inhibitors.
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PMID:Leukotriene B4-induced human melanocyte pigmentation and leukotriene C4-induced human melanocyte growth are inhibited by different isoquinolinesulfonamides. 130 61

The tumor promoter 12-O-tetradecanoylphorbol-13-acetate (TPA) at 10(-9) M stimulated the formation of osteoclast-like multinucleated cells (MNCs) in the presence of 1 alpha,25-dihydroxyvitamin D3 in rat bone marrow cultures. However, at 10(-7) M, it clearly inhibited 1 alpha,25-dihydroxyvitamin D3-dependent osteoclast-like MNC formation at 6 days of culture. In cultures treated with 10(-7) M TPA, numerous MNCs that lack the marker enzyme tartrate-resistant acid phosphatase (TRAP) were formed. These TRAP-negative MNCs had neither receptors for calcitonin nor dentine-resorbing activity. The reactivity of the cells against antirat macrophage antibodies was completely different from that of authentic osteoclasts. These data suggest that TRAP-negative MNCs formed in the presence of 10(-7) M TPA are macrophage polykaryons. Time-course studies showed that 10(-7) M TPA stimulated osteoclast-like MNC formation at 4 days of culture, but these osteoclast-like MNCs were converted to TRAP-negative MNCs. Furthermore, 1-(5-isoquinolinyl-sulfonyl)2-methylpiperazine (H-7), a protein kinase-C inhibitor, inhibited osteoclast-like MNC formation in a dose-dependent fashion. These results suggest that activation of protein kinase-C may play a role in osteoclast differentiation.
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PMID:12-O-tetradecanoylphorbol-13-acetate inhibits osteoclast-like cell differentiation in rat bone marrow cultures by inducing macrophage polykaryons. 131 Feb 76

Effects of parathyroid hormone substance (PTH) on the voltage-activated calcium current (ICa) were studied on intracellularly perfused neurones of the snail, Helix pomatia, under voltage-clamp conditions. Application of 0.1 nM PTH produced a marked potentiation of the current. The effect developed slowly (60-70 min) and remained after removal of PTH. Potentiation could be observed in most neurones, but varied considerably from cell to cell; in some neurones ICa was increased 2- to 3-fold. Addition of ethylenebis(oxonitrilo)tetraacetate (EGTA, 10 mM) to, or removal of adenosine 5'-triphosphate (ATP, 2 mM) from the intracellular perfusing solution resulted in a suppression or attenuation of the potentiating effect. The effect could be reproduced by the synthetic 1-34 amino acid fragment of PTH. Extracellularly applied protein kinase-C (PK-C) activator phorbol ester phorbol 12-myristate 13-acetate (PMA, 0.1-10 microM) produced a similar slow increase in ICa (up to 1.5- to 2-fold), while its inactive analogue (4 alpha-phorbol ester) had no effect on ICa. The effects of PTH and PMA were not additive. PK-C inhibitors [1-(5-isoquinoline-sulphonyl)-2-methylpiperazine hydrochloride] (H-7, 100 microM) and staurosporine (100 microM) as well as calcium channel antagonists Cd2+, verapamil, nifedipine and nimodipine depressed the effect of PTH. The chloride channel blocker 4,4'-diisothiocyanato-stilbene-2,2'-disulphonic acid (DIDS, 1 mM) did not affect the potentiating action of PTH. Activation of the adenylate cyclase system also potentiated ICa in some neurones, but this effect had a different time course and was additive to the effect of PTH.2=
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PMID:Parathyroid hormone enhances calcium current in snail neurones--simulation of the effect by phorbol esters. 132 Feb 49

Insulin induced phosphorylation and activation of the cGMP inhibited cAMP phosphodiesterase (cGI-PDE) in human platelets were demonstrated after isolation of the enzyme with specific polyclonal cGI-PDE antibodies. The demonstration of this insulin effect required suppression of basal cGI-PDE phosphorylation, through the use of the protein kinase inhibitor H-7 (1-(5-isoquinolinylsulfonyl)-2-methylpiperazine). The human platelet insulin receptor beta-subunit, previously identified as a 97 kDa polypeptide, was detected with the use of wheat germ agglutinin chromatography and anti-phosphotyrosine antibodies. These results suggest that insulin, through phosphorylation/activation of cGI-PDE, could decrease cAMP/cAMP dependent protein kinase (cAMP-PK) activity and thereby make the platelets more sensitive towards aggregating agents.
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PMID:Insulin induced phosphorylation and activation of the cGMP-inhibited cAMP phosphodiesterase in human platelets. 132 13

The respective roles of cAMP-dependent protein kinase (protein kinase A [PKA]) and protein kinase C (PKC) in the early stages of neurite outgrowth were examined in SH-SY-5Y human neuroblastoma cells. Forskolin or dbcAMP, agents that increase intracellular cAMP levels, and intracellular delivery of PKA catalytic subunit induced neurite outgrowth. The PKA inhibitor, N-(2-guanidinoethyl)-5-isoquinolinesulfonamide (HA 1004), prevented the increases, and decreased further the percentage of cells possessing short, filopodia-like neurites in the absence of inducers. In contrast to effects on PKA activation, PKC activation by 12-0-tetradecanoylphorbol-13-acetate (TPA) reduced the percentage of filopodia-like neurites elaborated by otherwise untreated cells, and prevented neurite outgrowth induced by PKA activators. PKC inhibitors 1-(5-isoquinolinesulfonyl)-2-methylpiperazine dihydrochloride (H7), staurosporine, and sphingosine induced neurite outgrowth. Neurites induced by PKA activation contained higher levels of tubulin immunoreactivity than those induced by PKC inhibition. Furthermore, PKA-induced neurites rapidly retracted in the presence of colchicine, while those elaborated following PKC inhibition were more resistant. These data suggest that neurites elaborated in response to PKA activation are dependent upon microtubule polymerization, and that neurite induction following PKC inhibition is mediated by a different mechanism. PKA activators and PKC inhibitors exerted additive effects on neurite outgrowth, suggesting that the distinct pathways regulated by these two kinases function cooperatively during neuritogenesis.
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PMID:Opposing influences of protein kinase activities on neurite outgrowth in human neuroblastoma cells: initiation by kinase A and restriction by kinase C. 133 89

1. A giant patch method was used to study the stimulatory effect of cytoplasmic MgATP on outward Na(+)-Ca2+ exchange current in inside-out cardiac membrane patches (1-10 G omega seals with 14-24 microns pipette tip diameters) excised from guinea-pig, rabbit and mouse myocytes. 2. To establish the validity of the method with respect to structure, bleb formation was examined with electron microscopy and with confocal fluorescence light microscopy. The blebs, which form as the sarcolemma detaches, excluded intracellular organelles and transverse tubules. The blebbed cells contained normal sarcomeres, sarcoplasmic reticulum, triads and diads. 3. To further establish the validity of the method for ion transport studies, measurements of Na(+)-K+ pump currents and charge movements are described briefly which demonstrate (i) free access to the cytoplasmic membrane side, (ii) MgATP dependence comparable to reconstituted pump (Kd, 94 microns), (iii) fast, rigorous concentration control and (iv) Na(+)-K+ pump densities in the range of whole-cell densities. 4. Stimulation of outward Na(+)-Ca2+ exchange current by MgATP attenuated exchange current decay during step increments of cytoplasmic sodium, shifted the secondary activation of outward exchange current by cytoplasmic calcium to lower free calcium concentrations and, particularly in mouse cardiac sarcolemma, induced cytoplasmic calcium-independent current. 5. Upon removal of MgATP the stimulatory effect usually decayed with a t50 (half-time) of about 3 min. However, the reversal took place much more rapidly (t50, 5-20 s) in patches from individual guinea-pig and rabbit myocyte batches. When decay was rapid, secondary activation by cytoplasmic calcium was shifted to higher free cytoplasmic calcium concentrations (Kd, 10-65 microns-free calcium). 6. With repeated applications of MgATP the rate and magnitude of the stimulatory effect progressively decreased. 7. The Kd for MgATP of the initial rate of stimulation of outward exchange current was 3 mM or greater. When decay was rapid, the steady-state dependence of exchange current on MgATP also had a Kd of 3 mM or greater. 8. Stimulation of Na(+)-Ca2+ exchange current by MgATP occurred in the absence of cytoplasmic calcium with 9 mM-EGTA. 9. The stimulatory effect of 2 mM-MgATP was not inhibited by up to 200 microM of the protein kinase inhibitor 1-(5-isoquinoline sulphonyl)-2-methylpiperazine (H7), or by peptide inhibitors of cyclic AMP-dependent protein kinase, protein kinase C and calcium-calmodulin-dependent protein kinase II.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:The giant cardiac membrane patch method: stimulation of outward Na(+)-Ca2+ exchange current by MgATP. 133 2

1. Messenger RNAs for the subunits of the muscle nicotinic acetylcholine receptor (nAChR) were expressed in Xenopus oocytes. A two-electrode voltage clamp was used to measure the acetylcholine (ACh)-induced macroscopic currents. In addition, patch-clamp techniques were used to study nAChR channels in whole cells and in outside-out patches excised from BC3H-1 cells and in patches from oocytes. The single-channel and macroscopic currents were modified by compounds that are usually used to study protein phosphorylation. 2. IBMX (3-isobutyl-1-methylxanthine) is a phosphodiesterase inhibitor. Because it elevates the intracellular concentration of adenosine 3',5'-cyclic monophosphate (cAMP), IBMX is often used to indirectly activate cAMP-dependent protein kinase. H-7 [1-(5-isoquinolinylsulfonyl)-2-methylpiperazine] is mainly used as a rather nonspecific inhibitor of protein kinase activity. Both IBMX and H-7 directly inhibit ACh-induced currents independent of their action on phosphorylation. This direct effect of these compounds is similar to the previously reported inhibition of nAChRs and K+ channels by forskolin, which is commonly used to elevate intracellular cAMP. 3. Macroscopic currents induced in the oocytes by 50 microM ACh had an average peak current of 605 nA, and the currents decayed biexponentially with tau of 15 and 225 s. When 300 microM H-7 was added simultaneously with the ACh, the average peak current was 228 nA and the tau were 1 and 108 s. When 500 microM IBMX was added simultaneously with the ACh, the average peak current was 308 nA and the tau were 9 and 237 s. H-7 and IBMX decreased the peak current induced by ACh, and the compounds increased the decay rate of the current. Under these experimental conditions, the IC50 for reduction of peak amplitude at -30 mV was 160 microM for H-7 and 475 microM for IBMX. 4. H-7 preferentially inhibits the open conformation of the nAChR channel, but there is also some inhibition of the closed channel. The inhibition is voltage dependent: inhibition decreases e-fold per 34 mV depolarization. H-7 does not become trapped within the closed channel and does not significantly alter desensitization under our experimental conditions. 5. H-7 and IBMX interrupt or terminate single-channel openings in membrane patches excised from oocytes or BC3H-1 cells.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Nicotinic acetylcholine receptors are directly affected by agents used to study protein phosphorylation. 138 18

We have investigated the role of protracted phosphatase inhibition and the consecutive protracted protein phosphorylation on neuronal viability. We found that in primary cultures of cerebellar granule neurons, the protracted (24-h) inhibition of the serine/threonine protein phosphatases 1 and 2A (EC 3.1.3.16) by treatment of the cultures with okadaic acid (OKA; 5-20 nM) caused neurotoxicity that could be inhibited by the protein kinase inhibitor 1-(5-isoquinolinylsulfonyl)-2-methylpiperazine (H7) or by the previous down-regulation of the neuronal protein kinase C (PKC; ATP:protein phosphotransferase; EC 2.7.1.37). PKC was down-regulated by exposure of the cultures for 24 h to 100 nM phorbol 12-myristate 13-acetate (TPA). The effect of the drugs used in the viability studies on the pattern of protein phosphorylation was measured by quantitative autoradiography. In particular, the 50- and 80-kDa protein bands showed dramatic changes in the degree of phosphorylation: increase by OKA and brief TPA treatment; decrease by H7 or 24 h of TPA treatment; and inhibition of the OKA-induced increase by H7 or 24 h of TPA treatment. The results suggest that the protracted phosphorylation, in particular that mediated by PKC, may lead to neuronal death and are in line with our previous suggestion that prolonged PKC translocation is operative in glutamate neurotoxicity.
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PMID:Pathological phosphorylation causes neuronal death: effect of okadaic acid in primary culture of cerebellar granule cells. 140 5

Catecholamines have been shown to activate hypothalamic corticotropin-releasing factor-41 (CRF) synthesis and release. In order to study the mechanisms involved, fetal hypothalamic cells were cultured and CRF release was measured by radioimmunoassay. Norepinephrine (NE) induced CRF release in a dose-dependent manner. Further studies were performed with a protein kinase C inhibitor, H-7(1-(5-isoquinolinesulfonyl)-2-methylpiperazine) and a protein kinase A inhibitor, IP-20. NE-stimulated CRF release was reduced by H-7 (5 and 50 microM) in a dose-dependent fashion, while 5 microM IP-20 resulted in a small but significant inhibition. Pretreatment of the cells for 15 h with 20 and 200 nM 12-O-tetradecanoylphorbol-13-acetate, which down-regulates protein kinase C activity, blocked the release of CRF in response to NE (1 microM), further supporting protein kinase C as a mediator for NE-activated CRF release. Pretreatment with 50 and 500 ng/ml pertussis toxin (15 h) resulted in a dose-dependent inhibition of NE-activated CRF release. Both dexamethasone and aldosterone at the concentrations of 1 microM reduced NE-induced CRF release. These results suggest that CRF can be released from hypothalamic neurons in response to NE through both protein kinase C- and protein kinase A-dependent mechanisms, and that pertussis toxin-sensitive G-proteins are also involved in this response. Furthermore, glucocorticoids and mineralocorticoids can reduce NE-activated CRF release from cultured hypothalamic cells.
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PMID:Mechanisms of norepinephrine mediated corticotropin-releasing factor-41 release from cultured fetal hypothalamic cells. 148 3

The protein kinase inhibitor 1-(5'-isoquinolinesulfonyl)-2-methylpiperazine (H7) has been widely used because of its ability to inhibit cyclic AMP- and cyclic GMP-dependent protein kinases (PKA and PKG) and protein kinase C (PKC) at roughly equal concentrations; it is much less potent on other kinases. Previous studies in other laboratories have found that H7 samples from different commercial sources have different properties in cellular studies and protein kinase C inhibition assays. We now report the results of chemical and biological tests which show that H7 samples also differ in chemical structure, again depending on their commercial source. Chemical synthesis and NMR spectroscopy indicate that H7 from most suppliers has the structure originally proposed for H7, while "H7" from another supplier is in fact its 3-methylpiperazine positional isomer.
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PMID:The structure and biological activities of the widely used protein kinase inhibitor, H7, differ depending on the commercial source. 153 Jun 23


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