Inhibitory effect of calcium-binding protein regucalcin on protein kinase C activity in rat liver cytosol.
Regucalcin, a calcium-binding protein isolated from rat liver cytosol, inhibited Ca2(+)- and phospholipid-dependent protein kinase (protein kinase C) activity in hepatic cytosol. With the increasing concentrations of Ca2+ or phosphatidylserine in the medium, regucalcin caused a remarkable inhibition of protein kinase C activity. Moreover, regucalcin significantly inhibited dioctanoylglycerol-activated protein kinase C. Regucalcin itself did not have protein kinase activity in either the presence or the absence of Ca2+ and phospholipids. These findings clearly indicate that regucalcin has an inhibitory effect on protein kinase C in hepatic cytosol. This inhibitory effect of regucalcin may be due to the regucalcin-induced Ca2+ binding and/or the direct binding of regucalcin to protein kinase C.
Yamaguchi
M
M
Department of Environmental Biochemistry, School of Pharmaceutical Sciences, University of Shizuoka, Japan.
Mori
S
S
D000818:Animals; D002118:Calcium / Q000494:pharmacology; D002135:Calcium-Binding Proteins / Q000494:pharmacology*; D002265:Carboxylic Ester Hydrolases; D003600:Cytosol / Q000201:enzymology; D004075:Diglycerides / Q000494:pharmacology; D047908:Intracellular Signaling Peptides and Proteins; D008099:Liver / Q000201:enzymology*; D008297:Male; D010718:Phosphatidylserines / Q000494:pharmacology; D011493:Protein Kinase C / Q000037:antagonists & inhibitors*; D051381:Rats; D011919:Rats, Inbred Strains; D015238:Sulfotransferases
D002135:Calcium-Binding Proteins; D004075:Diglycerides; 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; D002118:Calcium