Modulation of the Na,K-ATPase by Ca and intracellular proteins.
The activity of the Na,K-ATPase can be sensitive to physiological changes in Cai. Intracellular proteins such as calnaktin, calmodulin, and protein kinase C could regulate the pump during transient changes in Cai. The mechanisms by which these proteins interact with the Na,K-ATPase, their distribution in different kinds of cells, and their role in regulating the Na,K-ATPase are not yet determined. Preliminary data indicate that an increase in Cai within the physiological range could be associated with either a stimulation or an inhibition of enzyme activity or a change in the affinity of the Na,K-ATPase for ouabain. The type of response probably depends on the kind of cell, its associated intracellular proteins, and its physiological state. Ca and intracellular proteins could play a key role in the regulation of the Na,K-ATPase by hormones.
Yingst
D R
DR
Department of Physiology, Wayne State University, Detroit, Michigan 48201.
D002118:Calcium / Q000502:physiology*; D002147:Calmodulin / Q000502:physiology*; D011493:Protein Kinase C / Q000502:physiology*; D000254:Sodium-Potassium-Exchanging ATPase / Q000502:physiology*
D002147:Calmodulin; D011493:Protein Kinase C; D000254:Sodium-Potassium-Exchanging ATPase; D002118:Calcium