Phosphorylation of the catalytic subunit of Na+,K(+)-ATPase inhibits the activity of the enzyme.
We have examined two distinct protein kinases, cAMP-dependent protein kinase and protein kinase C, for their ability to phosphorylate and regulate the activity of three different types of Na+,K(+)-ATPase preparation. cAMP-dependent protein kinase phosphorylated purified shark rectal gland Na+,K(+)-ATPase to a stoichiometry of approximately 1 mol of phosphate per mol of alpha subunit. Protein kinase C phosphorylated purified shark rectal gland Na+,K(+)-ATPase to a stoichiometry of approximately 2 mol of phosphate per mol of alpha subunit. The phosphorylation by each of the kinases was associated with an inhibition of Na+,K(+)-ATPase activity of about 40-50%. These two protein kinases also inhibited the activity of a partially purified preparation of Na+,K(+)-ATPase from rat renal cortex and the activity of Na+,K(+)-ATPase present in preparations of basolateral membrane vesicles from rat renal cortex.
Bertorello
A M
AM
Department of Pediatrics, St. Göran's Children's Hospital, Karolinska Institutet, Stockholm, Sweden.
Aperia
A
A
Walaas
S I
SI
Nairn
A C
AC
Greengard
P
P
D000818:Animals; D015180:Electrophoresis, Gel, Two-Dimensional; D007700:Kinetics; D046911:Macromolecular Substances; D010449:Peptide Mapping; D010748:Phosphopeptides / Q000302:isolation & purification; D010766:Phosphorylation; D011493:Protein Kinase C / Q000378:metabolism*; D011494:Protein Kinases / Q000378:metabolism*; D012007:Rectum; D012627:Sebaceous Glands / Q000201:enzymology; D012754:Sharks; D000254:Sodium-Potassium-Exchanging ATPase / Q000302:isolation & purification / Q000378:metabolism*
D046911:Macromolecular Substances; D010748:Phosphopeptides; D011494:Protein Kinases; D011493:Protein Kinase C; D000254:Sodium-Potassium-Exchanging ATPase