Na⁺/K⁺ ATPase

The Na⁺/K⁺ ATPase is a membrane protein that is composed of two subunits - α and β. The pump maintains an essential electrochemical gradient within cells through the active transport of sodium (Na⁺) and potassium (K⁺) ions, and is the driving force for membrane excitability.

The Na⁺ gradient set by the Na⁺/K⁺ ATPase is functionally coupled to the Na⁺/Ca²⁺ exchanger (NCX) and therefore the Na⁺/K⁺ ATPase can also indirectly influence intracellular calcium concentration. For example, inhibition of the Na⁺/K⁺ ATPase in vascular smooth muscle cells and cardiomyocytes leads to the reversal of the Na⁺/Ca²⁺ exchanger and results in an increased force of contraction in the heart muscle and in arteries. This effect is induced therapeutically in the treatment of heart failure.

The Na⁺/K⁺ ATPase is also involved in additional cellular processes including excitability of nerves, and the transport of glucose and amino acids across the cell membrane. More recently, evidence has emerged of a second role for the Na⁺/K⁺ ATPase as a signaling mediator: the extracellular loops of the catalytic α subunit act as a receptor for cardiac glycosides. Upon ligand binding to the extracellular loops, the Na⁺/K⁺ ATPase interacts with neighboring proteins and influences cellular functions including protein synthesis.

External sources of pharmacological information for Na⁺/K⁺ ATPase :

• BJP Guide

Na⁺/K⁺ ATPase Gene Data