IMR Press / FBL / Volume 10 / Issue 3 / DOI: 10.2741/1724

Frontiers in Bioscience-Landmark (FBL) is published by IMR Press from Volume 26 Issue 5 (2021). Previous articles were published by another publisher on a subscription basis, and they are hosted by IMR Press on as a courtesy and upon agreement with Frontiers in Bioscience.


The γ subunit of Na/K-ATPase: an exceptional, small transmembrane protein

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1 Division of Renal Medicine, University of Colorado Health Sciences Center, School of Medicine, 4200 E. 9th Ave., Denver, CO 80262, USA

Academic Editor: Joseph Shapiro

Front. Biosci. (Landmark Ed) 2005, 10(3), 2604–2610;
Published: 1 September 2005
(This article belongs to the Special Issue Regulation and function of NaK-ATPase in health and disease)

The γ subunit has been characterized as a fine-tuning modulator of the Na/K-ATPase expressed in kidney tissues. This small single transmembrane domain protein interacts with the alpha subunit of Na/K-ATPase to increase affinity for ATP and decrease affinity for Na allowing medullary cells to continue pump activity under reduced cellular ATP levels. The γ subunit is undetectable in kidney cell cultures grown under isotonic conditions and expression is induced with acute or chronic exposure to hypertonicity. The γ subunit demonstrates remarkable regulatory complexity including induction by chloride ions rather than sodium, the differential expression of at least 2 isoforms, involvement of separate MAP kinase signaling pathways for transcription (JNK) and translation (PI3K) as well as cell type regulation of expression. Mutation in the transmembrane domain of the γ subunit has been implicated in cases of primary hypomagnesemia. Alternative roles have been established for the γ subunit in embryonic development and quite possibly additional functions in cell signaling as yet unrecognized may be possible.

γ subunit
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