Phosphorylation of the Na,K-ATPase by Ca,phospholipid-dependent and cAMP-dependent protein kinases. Mapping of the region phosphorylated by Ca,phospholipid-dependent protein kinase.
Ca,phospholipid-dependent (PKC) and cAMP-dependent (PKA) protein kinases phosphorylate the alpha-subunit of the Na,K-ATPase from duck salt gland with the incorporation of 0.3 and 0.5 mol 32P/mol of alpha-subunit, respectively. PKA (in contrast to PKC) phosphorylates the alpha-subunit only in the presence of detergents. Limited tryptic digestion of the Na,K-ATPase phosphorylated by PKC demonstrates that 32P is incorporated into the N-terminal 41-kDa fragment of the alpha-subunit. Selective chymotrypsin cleavage of phosphorylated enzyme yields a 35-kDa radioactive fragment derived from the central region of the alpha-subunit molecule. These findings suggest that PKC phosphorylates the alpha-subunit of the Na,K-ATPase within the region restricted by C3 and T1 cleavage sites.
Department of Biochemistry, Faculty of Biology, Moscow State University, Russia.
A V
AV
Chibalin
O D
OD
Lopina
S P
SP
Petukhov
L A
LA
Vasilets
D000818:Animals; D004372:Ducks; D066298:In Vitro Techniques; D010446:Peptide Fragments / Q000302:isolation & purification; D010766:Phosphorylation; D011487:Protein Conformation; D011493:Protein Kinase C / Q000378:metabolism; D011494:Protein Kinases / Q000378:metabolism*; D012491:Salt Gland / Q000378:metabolism; D000254:Sodium-Potassium-Exchanging ATPase / Q000737:chemistry / Q000378:metabolism*
D010446:Peptide Fragments; D011494:Protein Kinases; D011493:Protein Kinase C; D000254:Sodium-Potassium-Exchanging ATPase