Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:2.7.11.17 (CaMKII)
 4,029 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

1. Extracellular adenosine 5'-triphosphate (ATP) is an agonist for a P2Z receptor on human lymphocytes which mediates opening of a cation-selective ion channel, activation of phospholipase D and shedding of the adhesion molecule, L-selectin, from the cell surface. The isoquinolinesulphonamides, KN-62, (1-[N, O-bis(5-isoquinolinesulphonyl)-N-methyl-L-tyrosyl]-4-phenylpiperaz ine), a selective antagonist of Ca2+/calmodulin-dependent protein kinase II (CaMKII), and KN-04, (N-[1-[N-methyl-p-(5 isoquinoline sulphonyl)benzyl]-2-(4 phenylpiperazine)ethyl]-5-isoquinolinesulphonamide) an inactive analogue, were used to investigate the possible role of CaMKII in these diverse effects of extracellular ATP. 2. KN-62 potently antagonized ATP-stimulated Ba2+ influx into fura-2 loaded human lymphocytes with an IC50 of 12.7 +/- 1.5 nM (n = 3) and complete inhibition of the flux at a concentration of 500 nM. Similarly, KN-62 inhibited ATP-stimulated ethidium+ uptake, measured by time resolved flow cytometry, with an IC50 of 13.1 +/- 2.6 nM (n = 4) and complete inhibition of the flux at 500 nM. 3. KN-04 antagonized ATP-stimulated Ba2+ influx with an IC50 of 17.3 +/- 2.7 nM (n = 3). Similarly, KN-04 inhibited ATP-stimulated ethidium+ uptake with an IC50 of 37.2 +/- 8.9 nM (n = 4). Both fluxes were completely inhibited at 500 nM KN-04. 4. ATP-stimulated phospholipase D activity, measured in [3H]-oleic acid-labelled lymphocytes by the transphosphatidylation reaction, was antagonized by KN-62 and KN-04, with 50% inhibition at 5.9 +/- 1.2 and 9.7 +/- 2.8 nM (n = 3), respectively. Both KN-62 and KN-04 inhibited ATP-stimulated shedding of L-selectin, measured by flow cytometric analysis of cell surface L-selectin, with IC50 values of 31.5 +/- 4.5 and 78.7 +/- 10.8 nM (n = 3), respectively. Neither of the isoquinolinesulphonamides (500 nM) inhibited phorbol ester- or ionomycin-stimulated phospholipase D activity or phorbol ester-induced shedding of L-selectin. 5. The inhibitory effect of KN-62 or KN-04 on P2Z-mediated responses was slow in onset (5 min) and only partially reversed by washing the cells. 6. Both KN-62 and KN-04 (at 500 nM) had no effect on uridine 5'-triphosphate (UTP)-stimulated Ca2+ transients in fura-2 loaded human neutrophils, a response which is mediated by the P2Y2 receptor. 7. Thus, KN-62 and KN-04 are potent antagonists of the P2Z receptor and at nanomolar concentrations inhibit all known responses mediated by the P2Z receptor of human lymphocytes. In contrast, KN-62 and KN-04 had no effect on responses mediated by the P2Y2 receptor of neutrophils. Moreover, since KN-62 and KN-04 are almost equipotent, the P2Z-mediated responses do not involve CaMKII, but indicate that the isoquinolinesulphonamides are potent and direct inhibitors of the P2Z-receptor.
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PMID:The isoquinoline derivative KN-62 a potent antagonist of the P2Z-receptor of human lymphocytes. 911 69

Fluid and ion transport across biliary epithelium contributes to bile flow. Alterations of this function may explain hepatobiliary complications in cystic fibrosis (CF). We investigated electrogenic anion transport across intact non-CF and CF human gallbladder mucosa in Ussing-type chambers. In non-CF tissues, baseline transmural potential difference (PD), short-circuit current (Isc), and resistance (R) were -2.2 +/- 0.3 mV (lumen negative), 40.7 +/- 7.8 microA/cm2, and 66.5 +/- 9.6 Omega. cm2, respectively (n = 14). The addition of forskolin (10(-5) mol/L) to the apical and basolateral baths and that of adenosine 5'-triphosphate (ATP) (10(-4) mol/L) to the apical bath induced significant increases in Isc by 8.0 +/- 1.4 and 10.3 +/- 1.8 microA/cm2, respectively. Depletion of bathing solutions in Cl- and HCO3- significantly reduced baseline Isc and the forskolin- and ATP-induced increases in Isc. Anion secretion was stimulated by extracellular ATP via P2Y2 purinoceptors, as indicated by the effects of different nucleotides on Isc and on 36Cl efflux in cultured gallbladder epithelial cells. This effect was mediated by cytosolic calcium increase and Ca2+/calmodulin-dependent protein kinase II, as ascertained by using inhibitors. In CF preparations, basal PD and Isc were lower than in non-CF, and the response to forskolin was abolished, whereas the response to ATP was enhanced (P <.05 for all). We conclude that electrogenic anion secretion occurs in human gallbladder mucosa under basal state and is stimulated by an adenosine 3',5'-cyclic monophosphate (cAMP)-dependent pathway mediated by cystic fibrosis transmembrane conductance regulator (CFTR), and by exogenous ATP via a CFTR-independent pathway that is up-regulated in CF and involves P2Y2 purinoceptors and a calcium-dependent pathway.
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PMID:Regulation of electrogenic anion secretion in normal and cystic fibrosis gallbladder mucosa. 986 42

The involvement of P2Y receptors, which are activated by extracellular nucleotides, in proliferative regulation of human lung epithelial cells is unclear. Here we show that extracellular ATP and UTP stimulate bromodeoxyuridine (BrdU) incorporation into epithelial cell lines. The nucleotide efficacy profile [ATP = ADP > UDP >or= UTP > adenosine >or= 2-methylthioadenosine-5'-diphosphate, with alpha,beta-methylene adenosine 5'-triphosphate, 2',3'-O-(4-benzoylbenzoyl)adenosine 5'-triphosphate, AMP, UMP, and ATPalphaS inactive] and PCR analysis indicate involvement of P2Y2 and P2Y6 receptors. The signal transduction pathway, which, via the P2Y2 receptor, transmits the proliferative activity of ATP or UTP in A549 cells downstream of phospholipase C, depends on Ca2+/calmodulin-dependent protein kinase II and nuclear factor-kappaB, but not on protein kinase C. Signaling does not involve the mitogen-activated protein kinases extracellular signal-regulated kinases-1 and -2, the phosphatidylinositol 3-kinase pathway, or Src kinases. Thus nucleotides regulate proliferation of human lung epithelial cells by a novel pathway. The stimulatory effect of UTP, but not ATP, in A549 cells is attenuated by preincubation with interleukin-1beta and interleukin-6, but not tumor necrosis factor-alpha. This indicates an important role for the pyrimidine-activated P2Y receptor in the inflammatory response of lung epithelia. ATP antagonizes the antiproliferative effect of the anticancer drugs paclitaxel and etoposide, whereas it enhances the activity of cisplatin about fourfold. Thus pathways activated by extracellular nucleotides differentially control proliferation of lung epithelial tumor cells.
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PMID:ATP- and UTP-activated P2Y receptors differently regulate proliferation of human lung epithelial tumor cells. 1269 58

Immune cell function is modulated by changes in extracellular nucleotide levels. Here we used reverse transcription-PCR analyses, single cell Ca2+ imaging, and knock-out mice to define the receptors mediating nucleotide-induced Ca2+ signaling in resident peritoneal macrophages. In Ca2+-free buffer, the potent (K0.5<1 microm) stimulatory effect of UTP (or ATP) on endoplasmic reticulum (ER) Ca2+ release was abolished in cells isolated from P2Y2/P2Y4 double knock-out mice. Moreover, P2Y4(0/-), but not P2Y2-/-, macrophages responded to UTP. In P2Y2-/- macrophages, we could elicit Ca2+ responses to "pure" P2X receptor activation by applying ATP in buffer containing Ca2+. Purified UDP and ADP were ineffective agonists, although modest UDP-induced Ca2+ responses could be elicited in macrophages after "activation" with lipopolysaccharide and interferon-gamma. Notably, in Ca2+-free buffer, UTP-induced Ca2+ transients decayed within 1 min, and there was no response to repeated agonist challenge. Measurements of ER [Ca2+] with mag-fluo-4 showed that ER Ca2+ stores were depleted under these conditions. When extracellular Ca2+ was available, ER Ca2+ stores refilled, but Ca2+ increased to only approximately 40% of the initial value upon repeated UTP challenge. This apparent receptor desensitization persisted in GRK2+/- and GRK6-/- macrophages and after inhibition of candidate kinases protein kinase C and calmodulin-dependent kinase II. Initial challenge with UTP also reduced Ca2+ mobilization by complement component C5a (and vice versa). In conclusion, homologous receptor desensitization is not the major mechanism that rapidly dampens Ca2+ signaling mediated by P2Y2, the sole Gq-coupled receptor for UTP or ATP in macrophages. UDP responsiveness (P2Y6 receptor expression) increases following macrophage activation.
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PMID:Knock-out mice reveal the contributions of P2Y and P2X receptors to nucleotide-induced Ca2+ signaling in macrophages. 1698 Feb 98