lonomycin-stimulated Arachidonic Acid Release in Human Platelets: a Role for Protein Kinase C and Tyrosine Phosphorylation

1996 ◽  
Vol 76 (02) ◽  
pp. 248-252 ◽  
Author(s):  
Philip G Hargreaves ◽  
Susanne Jenner ◽  
Janet E Merritt ◽  
Stewart O Sage ◽  
Richard W Farndale
Keyword(s):  
Arachidonic Acid ◽  
Protein Kinase C ◽  
Protein Kinase ◽  
Tyrosine Phosphorylation ◽  
Human Platelets ◽  
Protein Tyrosine Phosphorylation ◽  
Arachidonic Acid Release ◽  
Protein Tyrosine ◽  
Kinase C ◽  
Acid Release

SummaryCollagen (10-90 Μg/ml) and ionomycin (1 ΜM; a calcium iono-phore) each evoked rises in intracellular free calcium, protein kinase C activity and arachidonic acid release in human platelets, and as previously demonstrated for collagen, ionomycin (1 p,M) stimulated protein tyrosine phosphorylation. However, at lower concentrations (60 and 250 nM) ionomycin selectively mobilised calcium. Ro31-8220 (a selective inhibitor of protein kinase C) inhibited (by 50%) ionomycin-stimulated arachidonic acid release. Genistein (an inhibitor of protein tyrosine kinases) also reduced by 50% ionomycin-stimulated arachidonic acid release. In combination, genistein and Ro31-8220 abolished ionomycin-stimulated arachidonic acid release. These findings show 1) that a rise in calcium is not sufficient, and 2) the activation of both protein kinase C and protein tyrosine phosphorylation is necessary, for full ionomycin-stimulated arachidonic acid release in human platelets.

scholarly journals Hydrogen peroxide-induced c-fos expression is mediated by arachidonic acid release: role of protein kinase C

1993 ◽  
Vol 21 (5) ◽  
pp. 1259-1263 ◽  
Author(s):  
Gadiparthi N. Rao ◽  
Bernard Lassegue ◽  
Kathy K. Griendling ◽  
R. Wayne Alexander ◽  
Bradford C. Berk
Keyword(s):  
Hydrogen Peroxide ◽  
Arachidonic Acid ◽  
Protein Kinase C ◽  
Protein Kinase ◽  
Arachidonic Acid Release ◽  
Kinase C ◽  
Acid Release ◽  
Fos Expression

scholarly journals Plasma from uninephrectomized rats stimulates phospholipid methylation and arachidonic acid release in renal-cortical slices

1989 ◽  
Vol 260 (2) ◽  
pp. 365-369 ◽  
Author(s):  
H Banfić ◽  
Z Gatalica
Keyword(s):  
Arachidonic Acid ◽  
Protein Kinase C ◽  
Protein Kinase ◽  
Phospholipase A2 ◽  
Arachidonic Acid Release ◽  
Kinase C ◽  
Graded Response ◽  
Acid Release ◽  
Cortical Slices

Phospholipid methylation and arachidonic acid release in renal-cortical slices was investigated in vitro after addition of plasma from uninephrectomized or sham-operated rats. Plasma from uninephrectomized rats (‘uni-plasma’) stimulated phospholipid methylation when obtained within the first 3 h after uninephrectomy. With different amounts of added plasma a graded response in phospholipid methylation was obtained. Addition of 50 nM-12-O-tetradecanoylphorbol 13-acetate for 10 min to intact slices also stimulated phospholipid methylation, whereas incubation of slices before addition of ‘uni-plasma’ with 100 microM-1-(5-isoquinolinylsulphonyl)-2-methylpiperazine prevented it, suggesting that protein kinase C stimulates phospholipid methylation in renal-cortical slices. Plasma from uninephrectomized rats also stimulates [3H]arachidonic acid release from phosphatidylcholine (PtdCho) and phosphatidylethanolamine (PtdEtn) via activation of phospholipase A2. Two mechanisms of phospholipase A2 activation are proposed: first, in which it is activated by protein kinase C and releases 3H radioactivity from PtdCho, and second, in which phospholipase A2 is stimulated by Ca2+ ions and releases 3H radioactivity from PtdEtn.

scholarly journals Permissive stimulation of Ca(2+)-induced phospholipase A2 by an adenosine receptor agonist in a pertussis toxin-sensitive manner in FRTL-5 thyroid cells: a new ‘cross-talk’ mechanism in Ca2+ signalling.

1994 ◽  
Vol 299 (3) ◽  
pp. 845-851 ◽  
Author(s):  
S Shimegi ◽  
F Okajima ◽  
Y Kondo
Keyword(s):  
Arachidonic Acid ◽  
Protein Kinase C ◽  
Protein Kinase ◽  
Phospholipase A2 ◽  
Phospholipase C ◽  
Arachidonic Acid Release ◽  
Thyroid Cells ◽  
Kinase C ◽  
Adenosine Receptor Agonist ◽  
Acid Release

We have described the pertussis toxin (PTX)-sensitive potentiation of P2-purinergic agonist-induced phospholipase C activation, Ca2+ mobilization and arachidonic acid release by an adenosine receptor agonist, N6-(L-2-phenylisopropyl)adenosine (PIA), which alone cannot influence any of these cellular activities [Okajima, Sato, Nazarea, Sho and Kondo (1989) J. Biol. Chem. 264, 13029-13037]. In the present study we have found that arachidonic acid release was associated with lysophosphatidylcholine production, and conclude that arachidonic acid is produced by phospholipase A2 in FRTL-5 thyroid cells. This led us to assume that PIA augments P2-purinergic arachidonic acid release by increasing [Ca2+]i which, in turn, activates Ca(2+)-sensitive phospholipase A2. The arachidonic acid-releasing response to PIA was, however, always considerably higher (3.1-fold increase) than the Ca2+ response (1.3-fold increase) to the adenosine derivative. In addition, arachidonic acid release induced by the [Ca2+]i increase caused by thapsigargin, an endoplasmic-reticulum Ca(2+)-ATPase inhibitor, or calcium ionophores was also potentiated by PIA without any effect on [Ca2+]i and phospholipase C activity. This action of PIA was also PTX-sensitive, but not affected by the forskolin- or cholera toxin-induced increase in the cellular cyclic AMP (cAMP), suggesting that a PTX-sensitive G-protein(s) and not cAMP mediates the PIA-induced potentiation of Ca(2+)-generated phospholipase A2 activation. Although acute phorbol ester activation of protein kinase C induced arachidonic acid release, P2-purinergic and alpha 1-adrenergic stimulation of arachidonic acid release was markedly increased by the protein kinase C down-regulation caused by the phorbol ester. This suggests a suppressive role for protein kinase C in the agonist-induced activation of arachidonic acid release. We conclude that PIA (and perhaps any of the G1-activating agonists) augments an agonist (maybe any of the Ca(2+)-mobilizing agents)-induced arachidonic acid release by activation of Ca(2+)-dependent phospholipase A2 in addition to enhancement of agonist-induced phospholipase C followed by an increase in [Ca2+]i.

Calcium-independent phospholipase A2 is regulated by a novel protein kinase C in human coronary artery endothelial cells

2005 ◽  
Vol 288 (2) ◽  
pp. C475-C482 ◽  
Author(s):  
Maureen C. Meyer ◽  
Pamela J. Kell ◽  
Michael H. Creer ◽  
Jane McHowat
Keyword(s):  
Endothelial Cells ◽  
Arachidonic Acid ◽  
Protein Kinase C ◽  
Coronary Artery ◽  
Protein Kinase ◽  
Arachidonic Acid Release ◽  
Human Coronary Artery ◽  
Phospholipid Hydrolysis ◽  
Kinase C ◽  
Acid Release

We demonstrated previously that thrombin stimulation of endothelial cells activates a membrane-associated, Ca2+-independent phospholipase A2 (iPLA2) that selectively hydrolyzes arachidonylated plasmalogen phospholipids. We report that incubation of human coronary artery endothelial cells (HCAEC) with phorbol 12-myristate 13-acetate (PMA) to activate protein kinase C (PKC) resulted in hydrolysis of cellular phospholipids similar to that observed with thrombin stimulation (0.05 IU/ml; 10 min). Thrombin stimulation resulted in a decrease in arachidonylated plasmenylcholine (2.7 ± 0.1 vs. 5.3 ± 0.4 nmol PO4/mg of protein) and plasmenylethanolamine (7.5 ± 1.0 vs. 12.0 ± 0.9 nmol PO4/mg of protein). Incubation with PMA resulted in decreases in arachidonylated plasmenylcholine (3.2 ± 0.3 nmol PO4/mg of protein) and plasmenylethanolamine (6.0 ± 1.0 nmol PO4/mg of protein). Incubation of HCAEC with the selective iPLA2 inhibitor bromoenol lactone (5 mM; 10 min) inhibited accelerated plasmalogen phospholipid hydrolysis in response to both PMA and thrombin stimulation. Incubation of HCAEC with PMA (100 nM; 5 min) resulted in increased arachidonic acid release (7.1 ± 0.3 vs. 1.1 ± 0.1%) and increased production of lysoplasmenylcholine (1.4 ± 0.2 vs. 0.6 ± 0.1 nmol PO4/mg of protein), similar to the responses observed with thrombin stimulation. Downregulation of PKC by prolonged exposure to PMA (100 nM; 24 h) completely inhibited thrombin-stimulated increases in arachidonic acid release (7.1 ± 0.6 to 0.5 ± 0.1%) and lysoplasmenylcholine production (2.0 ± 0.1 to 0.2 ± 0.1 nmol PO4/mg of protein). These data suggest that PKC activates iPLA2 in HCAEC, leading to accelerated plasmalogen phospholipid hydrolysis and increased phospholipid metabolite production.

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