Adrenergic, dopaminergic, and muscarinic receptor stimulation leads to PKA phosphorylation of Na-K-ATPase.
Na-K-adenosinetriphosphatase (Na-K-ATPase) is a potential target for phosphorylation by protein kinase A (PKA) and C (PKC). We have investigated whether the Na-K-ATPase alpha-subunit becomes phosphorylated at its PKA or PKC phosphorylation sites upon stimulation of G protein-coupled receptors primarily linked either to the PKA or the PKC pathway. COS-7 cells, transiently or stably expressing Bufo marinus Na-K-ATPase wild-type alpha- or mutant alpha-subunits affected in its PKA or PKC phosphorylation site, were transfected with recombinant DNA encoding beta 2- or alpha 1-adrenergic (AR), dopaminergic (D1A-R), or muscarinic cholinergic (M1-AChR) receptor subspecies. Agonist stimulation of beta 2-AR or D1A-R led to phosphorylation of the wild-type alpha-subunit, as well as the PKC mutant, but not of the PKA mutant, indicating that these receptors can phosphorylate the Na-K-ATPase via PKA activation. Surprisingly, stimulation of the alpha 1B-AR, alpha 1C-AR, and M1-AChR also increased the phosphorylation of the wild-type alpha-subunit and its PKC mutant but not of its PKA mutant. Thus the phosphorylation induced by these primarily phospholipase C-linked receptors seems mainly mediated by PKA activation. These data indicate that the Na-K-ATPase alpha-subunit can act as an ultimate target for PKA phosphorylation in a cascade starting with agonist-receptor interaction and leading finally to a phosphorylation-mediated regulation of the enzyme.
Beguin
P
P
Institute of Pharmacology and Toxicology, University of Lausanne, Switzerland.
Beggah
A
A
Cotecchia
S
S
Geering
K
K
D000818:Animals; D002024:Bufo marinus / Q000235:genetics; D002460:Cell Line; D017868:Cyclic AMP-Dependent Protein Kinases / Q000819:agonists / Q000378:metabolism*; D018491:Dopamine Agonists / Q000494:pharmacology; D004837:Epinephrine / Q000494:pharmacology; D018721:Muscarinic Agonists / Q000494:pharmacology; D009154:Mutation; D010766:Phosphorylation; D011493:Protein Kinase C / Q000235:genetics / Q000378:metabolism; D011941:Receptors, Adrenergic / Q000378:metabolism*; D011954:Receptors, Dopamine / Q000378:metabolism*; D011976:Receptors, Muscarinic / Q000378:metabolism*; D000254:Sodium-Potassium-Exchanging ATPase / Q000235:genetics / Q000378:metabolism*; D014162:Transfection
D018491:Dopamine Agonists; D018721:Muscarinic Agonists; D011941:Receptors, Adrenergic; D011954:Receptors, Dopamine; D011976:Receptors, Muscarinic; D017868:Cyclic AMP-Dependent Protein Kinases; D011493:Protein Kinase C; D000254:Sodium-Potassium-Exchanging ATPase; D004837:Epinephrine