title: Modulation of the activity of the (Ca2+ + Mg2+)-dependent adenosine triphosphatase of the human erythrocyte.
abstract: We previously reported that the activity of the (Ca2+ + Mg2+)-dependent adenosine triphosphatase (ATPase) of the human erythrocyte membrane is inhibited by micromolar or nanomolar concentrations of cyclic AMP. Our further studies have now indicated that the inhibition of (Ca2+ + Mg2+)-dependent phosphohydrolase activity requires the participation of a membrane-associated cyclic AMP-dependent protein kinase and a membrane-associated protein substrate that is distinct from the ATPase itself. We have furthermore, identified a 20 kDa membrane protein which undergoes phosphorylation that is promoted by micromolar, but not millimolar, concentrations of cyclic AMP and which, when phosphorylated, undergoes dephosphorylation that is promoted by Ca2+. We suggest that this membrane component can participate in the modulation of the activity of the (Ca2+ + Mg2+)-dependent ATPase of the human erythrocyte.
mesh_terms: D017301:Ca(2+) Mg(2+)-ATPase; D000252:Calcium-Transporting ATPases / Q000097:blood*; D000242:Cyclic AMP / Q000494:pharmacology*; D004910:Erythrocyte Membrane / Q000201:enzymology*; D004912:Erythrocytes / Q000201:enzymology*; D006801:Humans; D007700:Kinetics; D008565:Membrane Proteins / Q000097:blood; D010766:Phosphorylation; D011494:Protein Kinases / Q000097:blood*; D012995:Solubility
chemical_list: D008565:Membrane Proteins; D000242:Cyclic AMP; D011494:Protein Kinases; D017301:Ca(2+) Mg(2+)-ATPase; D000252:Calcium-Transporting ATPases