Hyperpolarization-activated inward leakage currents caused by deletion or mutation of carboxy-terminal tyrosines of the Na+/K+-ATPase {alpha} subunit.

ABSTRACT: The Na(+)/K(+)-ATPase mediates electrogenic transport by exporting three Na(+) ions in exchange for two K(+) ions across the cell membrane per adenosine triphosphate molecule. The location of two Rb(+) ions in the crystal structures of the Na(+)/K(+)-ATPase has defined two "common" cation binding sites, I and II, which accommodate Na(+) or K(+) ions during transport. The configuration of site III is still unknown, but the crystal structure has suggested a critical role of the carboxy-terminal KETYY motif for the formation of this "unique" Na(+) binding site. Our two-electrode voltage clamp experiments on Xenopus oocytes show that deletion of two tyrosines at the carboxy terminus of the human Na(+)/K(+)-ATPase alpha(2) subunit decreases the affinity for extracellular and intracellular Na(+)

SUBMITTER: Meier S 

PROVIDER: S-EPMC2812498 | biostudies-literature | 2010 Feb

REPOSITORIES: biostudies-literature