Regulation of reconstituted renal Na+/H+ exchanger by calcium-dependent protein kinases.
Studies were performed to determine the effect of protein phosphorylation mediated by calcium-calmodulin-dependent multifunctional protein kinase II and calcium-phospholipid-dependent protein kinase on Na+/H+ exchange activity. Proteins from the apical membrane of the proximal tubule of the rabbit kidney were solubilized in octyl glucoside and incubated in phosphorylating solutions containing the protein kinase. 22Na+ uptake was determined subsequently after reconstitution of the proteins into proteoliposomes. Calcium-calmodulin-dependent multifunction protein kinase II inhibited the amiloride-sensitive component of proton gradient-stimulated Na+ uptake in a dose-dependent manner. The inhibitory effect of this kinase had an absolute requirement for calmodulin, Ca2+, and ATP. Calcium-phospholipid-dependent protein kinase stimulated the amiloride-sensitive component of proton gradient-stimulated Na+ uptake in a dose-dependent manner. The stimulating effect of this kinase had an absolute requirement for ATP, Ca2+, and an active phorbol ester. These experiments indicate that Na+/H+ exchange activity of proteoliposomes reconstituted with proteins from renal brush-border membranes are inhibited by protein phosphorylation mediated by calcium-calmodulin-dependent multifunctional protein kinase II and stimulated by that mediated by calcium-calmodulin-dependent protein kinase.
Weinman
E J
EJ
Department of Medicine, University of Texas Medical School, Houston 77025.
Dubinsky
W P
WP
Fisher
K
K
Steplock
D
D
Dinh
Q
Q
Chang
L
L
Shenolikar
S
S
D000255:Adenosine Triphosphate / Q000378:metabolism; D000818:Animals; D001345:Autoradiography; D001693:Biological Transport, Active; D002147:Calmodulin / Q000378:metabolism*; D002352:Carrier Proteins / Q000378:metabolism*; D002462:Cell Membrane / Q000378:metabolism; D004591:Electrophoresis, Polyacrylamide Gel; D006863:Hydrogen-Ion Concentration; D007687:Kidney Tubules, Proximal / Q000378:metabolism*; D008871:Microvilli / Q000378:metabolism; D010766:Phosphorylation; D011493:Protein Kinase C / Q000378:metabolism; D011494:Protein Kinases / Q000378:metabolism*; D011817:Rabbits; D017923:Sodium-Hydrogen Exchangers; D017871:Calcium-Calmodulin-Dependent Protein Kinases
D000255:Adenosine Triphosphate; D002147:Calmodulin; D002352:Carrier Proteins; D011493:Protein Kinase C; D011494:Protein Kinases; D017923:Sodium-Hydrogen Exchangers; D017871:Calcium-Calmodulin-Dependent Protein Kinases