title: Nitric oxide activates PKCalpha and inhibits Na+-K+-ATPase in opossum kidney cells.
abstract: Nitric oxide (NO) reduces the molecular activity of Na+-K+-ATPase in opossum kidney (OK) cells, a proximal tubule cell line. In the present study, we investigated the cellular mechanisms for the inhibitory effect of NO on Na+-K+-ATPase. Sodium nitroprusside (SNP), a NO donor, inhibited Na+-K+-ATPase in OK cells, but not in LLC-PK1 cells, another proximal tubule cell line. Similarly, phorbol 12-myristate 13-acetate, a protein kinase C (PKC) activator, inhibited Na+-K+-ATPase in OK, but not in LLC-PK1, cells. PKC inhibitors staurosporine or calphostin C, but not the protein kinase G inhibitor KT-5823, abolished the inhibitory effect of NO on Na+-K+-ATPase in OK cells. Immunoblotting demonstrated that treatment with NO donors caused significant translocation of PKCalpha from cytosolic to particulate fractions in OK, but not in LLC-PK1, cells. Furthermore, the translocation of PKCalpha in OK cells was attenuated by either the phospholipase C inhibitor U-73122 or the soluble guanylate cyclase inhibitor 1H-[1,2,4]oxadiazolo-[4,3-a]quinoxalin-1-one. U-73122 also blunted the inhibitory effect of SNP on Na+-K+-ATPase in OK cells. The phospholipase A2 inhibitor AACOCF3 did not blunt the inhibitory effect of SNP on Na+-K+-ATPase in OK cells. AACOCF3 alone, however, also decreased Na+-K+-ATPase activity in OK cells. In conclusion, our results demonstrate that NO activates PKCalpha in OK, but not in LLC-PK1, cells. The activation of PKCalpha in OK cells by NO is associated with inhibition of Na+-K+-ATPase.
authors.affiliation: Departments of Medicine and Physiology and Biophysics, Mayo Clinic and Foundation, Rochester, Minnesota 55905, USA.
authors.forename: M
authors.initials: M
authors.lastname: Liang
authors.forename: F G
authors.initials: FG
authors.lastname: Knox
mesh_terms: D000470:Alkaloids / Q000494:pharmacology; D000818:Animals; D001095:Arachidonic Acids / Q000494:pharmacology; D002227:Carbazoles; D002460:Cell Line; D004789:Enzyme Activation; D004791:Enzyme Inhibitors / Q000494:pharmacology; D004963:Estrenes / Q000494:pharmacology; D007211:Indoles; D007527:Isoenzymes / Q000378:metabolism*; D007668:Kidney / Q000201:enzymology*; D007687:Kidney Tubules, Proximal / Q000201:enzymology; D007700:Kinetics; D009281:Naphthalenes / Q000494:pharmacology; D009569:Nitric Oxide / Q000502:physiology*; D020030:Nitric Oxide Donors / Q000494:pharmacology*; D009599:Nitroprusside / Q000494:pharmacology*; D009893:Opossums; D011493:Protein Kinase C / Q000378:metabolism*; D051571:Protein Kinase C-alpha; D011760:Pyrrolidinones / Q000494:pharmacology; D000254:Sodium-Potassium-Exchanging ATPase / Q000037:antagonists & inhibitors*; D019311:Staurosporine / Q000494:pharmacology; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology
chemical_list: D000470:Alkaloids; D001095:Arachidonic Acids; D002227:Carbazoles; D004791:Enzyme Inhibitors; D004963:Estrenes; D007211:Indoles; D007527:Isoenzymes; D009281:Naphthalenes; D020030:Nitric Oxide Donors; D011760:Pyrrolidinones; C081565:arachidonyltrifluoromethane; C060229:1-(6-((3-methoxyestra-1,3,5(10)-trien-17-yl)amino)hexyl)-1H-pyrrole-2,5-dione; C073601:KT 5823; D009599:Nitroprusside; D009569:Nitric Oxide; D011493:Protein Kinase C; D051571:Protein Kinase C-alpha; D000254:Sodium-Potassium-Exchanging ATPase; D019311:Staurosporine; C058819:calphostin C; D013755:Tetradecanoylphorbol Acetate