[The evaluation of the role of endogenous Ca-dependent regulators and protein kinases in activating and inhibiting ion-transport ATPases].
The data on hormonal regulation of ATP-driving ion pumps are contradictory depending on the object used: whether native cells or isolated membranes. To eliminate this contrariety, we studied the ion transporting ATPases in saponin-permeabilized cells in the presence of all endogenous regulators. In permeabilized erythrocytes we obtained the presence of Ca(2+)-dependent activation of Ca(2+)-ATPase by factor(s) not affected by calmodulin antagonist R24571. We obtained also Ca(2+)-dependent activation and inhibition of Na+,K(+)-ATPase. At a concentration of Mg(2+)-ions corresponding to the intracellular level (370 microM), the 0.5-0.7 microM Ca(2+)-activated Na+,K(+)-ATPase (up to 3-fold), whereas the 1-5 microM Ca2+ inhibited it. The cyclic AMP (10(-5) M) inhibited or eliminated Ca(2+)-dependent activation. The decrease in Mg(2+)-ion concentration to 50 microM eliminated the activation and strengthened the inhibition, which reached 100% at the 1-2 microM Ca2+ concentration. The washing of membranes with EGTA eliminated Ca2+ effects on Na+,K(+)-ATPase. These data suggest that the ion-transporting ATPases are activated or inhibited by Ca(2+)-dependent regulators whose activities may be changed by protein kinase catalysed phosphorylation.
Petruniaka
V V
VV
Paniushkina
E A
EA
D000251:Adenosine Triphosphatases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D000818:Animals; D001692:Biological Transport / Q000187:drug effects; D000252:Calcium-Transporting ATPases / Q000037:antagonists & inhibitors / Q000097:blood; D002147:Calmodulin / Q000097:blood* / Q000187:drug effects; D002463:Cell Membrane Permeability / Q000187:drug effects; D004789:Enzyme Activation / Q000187:drug effects; D004910:Erythrocyte Membrane / Q000187:drug effects / Q000201:enzymology; D007477:Ions; D011494:Protein Kinases / Q000097:blood* / Q000187:drug effects; D012503:Saponins / Q000494:pharmacology; D000254:Sodium-Potassium-Exchanging ATPase / Q000037:antagonists & inhibitors / Q000097:blood
D002147:Calmodulin; D007477:Ions; D012503:Saponins; D011494:Protein Kinases; D000251:Adenosine Triphosphatases; D000252:Calcium-Transporting ATPases; D000254:Sodium-Potassium-Exchanging ATPase
Otsenka roli éndogennykh Ca-zavisimykh reguliatorov i proteinkinaz v aktivatsii i ingibirovanii iontransportnykh ATFaz.