Key result
Cys-to-Tyr mutation in Na-K-ATPase alpha-1 subunit reduces sensitivity to digitoxin and external K+ versus wild type.
Why the study?
The role of the Cys residue in the first transmembrane region of the Na(+)-K(+)-ATPase alpha 1-subunit in ion transport activity and cardiac glycoside binding was unclear.
Population
HeLa cells expressing wild-type or mutant Na(+)-K(+)-ATPase alpha 1-subunit cDNAs
Comparison
Cys-to-Tyr or Cys-to-Ala mutations vs wild-type alpha 1-subunit
Design
Preclinical experimental study
Authors
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No immediate change to digitoxin use; extends molecular mapping of Na/K-ATPase interactions but leaves clinical translation open.
The Cys residue in the first transmembrane region of the Na(+)-K(+)-ATPase alpha 1-subunit is critical for both cardiac glycoside binding and sensitivity to external K+.
Yamamoto et al. (1996) studied this question. Mutations in the first transmembrane region of Na(+)-K(+)-ATPase alpha 1-subunit vs. Wild-type alpha 1-subunit was evaluated on Pump currents and sensitivity to cardiac glycosides and external K+. A Cys-to-Tyr mutation in the Na(+)-K(+)-ATPase alpha 1-subunit decreased sensitivity to digitoxin and external K+ compared with wild type, indicating this residue participates in both interactions.
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