title: Tyrosine kinase is involved in angiotensin II-stimulated phospholipase D activation in aortic smooth muscle cells: function of Ca2+ influx.
abstract: In the present study, we examined the effect of angiotensin II (Ang II) on phosphatidylcholine-hydrolyzing phospholipase D activity in subcultured rat aortic smooth muscle cells (SMC). Ang II dose-dependently stimulated the formation of choline and inositol phosphates. The effect of Ang II on the formation of inositol phosphates (EC50 was 0.249 +/- 0.091 nM) was more potent than that on the formation of choline (EC50 was 2.39 +/- 1.29 nM). A combination of Ang II and 12-O-tetradecanoylphorbol-13-acetate (TPA), an activator of protein kinase C, additively stimulated the formation of choline. Staurosporine, an inhibitor of protein kinases, inhibited the TPA-induced formation of choline, but had little effect on the Ang II-induced choline formation. Ang II stimulated Ca2+ influx from extracellular space time- and dose-dependently. The depletion of extracellular Ca2+ by (ethylenebis(oxyethylenenitrilo)) tetraacetic acid (EGTA) significantly reduced the Ang II-induced formation of choline. Genistein and tyrphostin, protein tyrosine kinase inhibitors, significantly suppressed the Ang II-induced Ca2+ influx. Genistein and tyrphostin also suppressed the Ang II-induced formation of choline. These results suggest that Ang II stimulates phosphatidylcholine-hydrolyzing phospholipase D due to Ca2+ influx from the extracellular space in rat aortic SMC, and that protein tyrosine kinase is involved in the Ang II-induced Ca2+ influx, resulting in the promotion of phosphatidylcholine hydrolysis.
authors.affiliation: First Department of Internal Medicine, Nagoya University School of Medicine, Japan.
authors.forename: A
authors.initials: A
authors.lastname: Suzuki
authors.forename: J
authors.initials: J
authors.lastname: Shinoda
authors.forename: Y
authors.initials: Y
authors.lastname: Oiso
authors.forename: O
authors.initials: O
authors.lastname: Kozawa
mesh_terms: D000470:Alkaloids / Q000494:pharmacology; D000804:Angiotensin II / Q000494:pharmacology*; D000818:Animals; D001011:Aorta / Q000166:cytology*; D001692:Biological Transport; D000001:Calcimycin / Q000494:pharmacology; D002118:Calcium / Q000502:physiology*; D002478:Cells, Cultured; D002794:Choline / Q000096:biosynthesis; D004789:Enzyme Activation / Q000187:drug effects; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005110:Extracellular Space / Q000378:metabolism; D019833:Genistein; D007295:Inositol Phosphates / Q000096:biosynthesis; D007476:Ionophores / Q000494:pharmacology; D007529:Isoflavones / Q000494:pharmacology; D008563:Membrane Lipids / Q000378:metabolism; D009124:Muscle Proteins / Q000378:metabolism*; D009131:Muscle, Smooth, Vascular / Q000187:drug effects* / Q000201:enzymology; D010713:Phosphatidylcholines / Q000378:metabolism; D043265:Phosphatidylinositol Diacylglycerol-Lyase; D010739:Phospholipase D / Q000378:metabolism*; D010727:Phosphoric Diester Hydrolases / Q000378:metabolism; D010766:Phosphorylation / Q000187:drug effects; D011493:Protein Kinase C / Q000378:metabolism; D011499:Protein Processing, Post-Translational / Q000187:drug effects; D011505:Protein-Tyrosine Kinases / Q000502:physiology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D015398:Signal Transduction / Q000187:drug effects; D019311:Staurosporine; D013729:Terpenes / Q000494:pharmacology; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D019284:Thapsigargin
chemical_list: D000470:Alkaloids; D004791:Enzyme Inhibitors; D007295:Inositol Phosphates; D007476:Ionophores; D007529:Isoflavones; D008563:Membrane Lipids; D009124:Muscle Proteins; D010713:Phosphatidylcholines; D013729:Terpenes; D000804:Angiotensin II; D000001:Calcimycin; D019284:Thapsigargin; D019833:Genistein; D011505:Protein-Tyrosine Kinases; D011493:Protein Kinase C; D010727:Phosphoric Diester Hydrolases; D010739:Phospholipase D; C065017:glycoprotein phospholipase D; D043265:Phosphatidylinositol Diacylglycerol-Lyase; D019311:Staurosporine; D002794:Choline; D013755:Tetradecanoylphorbol Acetate; D002118:Calcium