title: Inhibitory effect of calcium-binding protein regucalcin on protein kinase C activity in rat renal cortex cytosol.
abstract: The effect of regucalcin, a calcium-binding protein, on Ca2+-and phospholipid-dependent protein kinase (protein kinase C) activity in the cytosol of rat kidney cortex was investigated. With increasing concentrations of Ca2+, phosphatidylserine or dioctanoylglycerol in the reaction mixture, regucalcin (10[-8] M) caused a remarkable inhibition of protein kinase C activity. Regucalcin did not have a significant effect on protein kinase C activity in the presence of phosphatidylserine or dioctanoylglycerol without Ca2+ addition. Moreover, regucalcin significantly inhibited phorbol 12-myristate 13-acetate (PMA)-increased protein kinase C activity. Meanwhile, staurosporine (10[-9] M) caused a significant inhibition of protein kinase C activity. This inhibition was further enhanced by regucalcin addition. Regucalcin itself did not have protein kinase activity in either the presence or the absence of both Ca2+ and phospholipids. These results clearly indicate that regucalcin has an inhibitory effect on protein kinase C activity in the cytosol of rat kidney cortex. This inhibitory effect may be partly due to the regucalcin-induced Ca2+ binding.
authors.affiliation: Laboratory of Endocrinology and Molecular Metabolism, Graduate School of Nutritional Sciences, University of Shizuoka, Yada, Shizuoka City, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Kurota
authors.forename: M
authors.initials: M
authors.lastname: Yamaguchi
mesh_terms: D000818:Animals; D002135:Calcium-Binding Proteins / Q000494:pharmacology*; D002265:Carboxylic Ester Hydrolases; D003600:Cytosol / Q000187:drug effects / Q000201:enzymology; D004075:Diglycerides / Q000494:pharmacology; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D047908:Intracellular Signaling Peptides and Proteins; D007672:Kidney Cortex / Q000187:drug effects / Q000201:enzymology*; D008297:Male; D010718:Phosphatidylserines / Q000494:pharmacology; D011493:Protein Kinase C / Q000037:antagonists & inhibitors*; D051381:Rats; D017208:Rats, Wistar; D015238:Sulfotransferases; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology
chemical_list: D002135:Calcium-Binding Proteins; D004075:Diglycerides; D004791:Enzyme Inhibitors; D047908:Intracellular Signaling Peptides and Proteins; D010718:Phosphatidylserines; C044295:1,2-dioctanoylglycerol; D011493:Protein Kinase C; D015238:Sulfotransferases; C028152:alcohol sulfotransferase; D002265:Carboxylic Ester Hydrolases; C513325:Rgn protein, rat; D013755:Tetradecanoylphorbol Acetate