Stimulation of ouabain-sensitive 86Rb+ uptake and Na+,K+-ATPase alpha-subunit phosphorylation by a cAMP-dependent signalling pathway in intact cells from rat kidney cortex.
We investigated in intact cortical kidney tubules the role of PKA-mediated phosphorylation in the short-term control of Na+,K+-ATPase activity. The phosphorylation level of Na+,K+-ATPase was evaluated after immunoprecipitation of the enzyme from 32P-labelled cortical tubules and the cation transport activity of Na+,K+-ATPase was measured by ouabain-sensitive 86Rb+ uptake. Incubation of cells with cAMP analogues (8-bromo-cAMP, dibutyryl-cAMP) or with forskolin plus 3-isobutyl-1-methylxanthine increased the phosphorylation level of the Na+,K+-ATPase alpha-subunit and stimulated ouabain-sensitive 86Rb+ uptake. Inhibition of PKA by H-89 blocked the effects of dibutyryl-cAMP on both phosphorylation and 86Rb+ uptake processes. The results suggest that phosphorylation by PKA stimulates the Na+,K+-ATPase activity.
Division of Néphrology, Hôpital Cantonal Universitaire, Genève, Switzerland.
M L
ML
Carranza
E
E
Féraille
M
M
Kiroytcheva
M
M
Rousselot
H
H
Favre
D015056:1-Methyl-3-isobutylxanthine / Q000494:pharmacology; D015124:8-Bromo Cyclic Adenosine Monophosphate / Q000494:pharmacology; D000818:Animals; D003994:Bucladesine / Q000494:pharmacology; D005576:Colforsin / Q000494:pharmacology; D000242:Cyclic AMP / Q000378:metabolism*; D017868:Cyclic AMP-Dependent Protein Kinases / Q000378:metabolism*; D066298:In Vitro Techniques; D017136:Ion Transport; D007672:Kidney Cortex / Q000201:enzymology / Q000378:metabolism*; D007684:Kidney Tubules / Q000201:enzymology / Q000378:metabolism; D008297:Male; D010042:Ouabain / Q000494:pharmacology; D010766:Phosphorylation; D051381:Rats; D017208:Rats, Wistar; D012413:Rubidium / Q000378:metabolism*; D015398:Signal Transduction; D000254:Sodium-Potassium-Exchanging ATPase / Q000378:metabolism*
D005576:Colforsin; D015124:8-Bromo Cyclic Adenosine Monophosphate; D010042:Ouabain; D003994:Bucladesine; D000242:Cyclic AMP; D017868:Cyclic AMP-Dependent Protein Kinases; D000254:Sodium-Potassium-Exchanging ATPase; D012413:Rubidium; D015056:1-Methyl-3-isobutylxanthine