Document Type
Article
Publication Date
Spring 4-6-2007
Abstract
Recent studies have ascribed many non-pumping functions to the Na/K-ATPase. Here, we present experimental evidence demonstrating that over half of the plasma membrane Na/KATPase in LLC-PK1 cells is performing cellular functions other than ion pumping. This “non-pumping” pool of Na/K-ATPase, like the pumping pump, binds ouabain. Depletion of either cholesterol or caveolin-1 moves some of the “non-pumping” Na/KATPase into the pumping pool. Graded knock-down of the 1 subunit of the Na/K-ATPase eventually results in loss of this “non-pumping” pool while preserving the pumping pool. Our prior studies indicate that a loss of the non-pumping pool is associated with a loss of receptor function as evidenced by the failure of ouabain administration to induce the activation of Src and/or ERK. Therefore, our new findings suggest that a substantial amount of surface-expressed Na/K-ATPase, at least in some types of cells, may function as non-canonical ouabain-binding receptors.
Recommended Citation
Liang M, J Tian, L Liu, S Pierre, J Liu, J Shapiro, and ZJ Xie. 2007. Identification of a pool of non-pumping Na/K-ATPase. J. Biol. Chem. 282:10585-93.
Comments
The version of record is available from the publisher at http://www.jbc.org/content/282/14/10585.full.pdf+html. This research was originally published in The Journal of Biological Chemistry. Man Liang, Jiang Tian, Lijun Liu, Sandrine Pierre, Jiang Liu, Joseph Shapiro, and Zi-Jian Xie. Identification of a pool of non-pumping Na/K-ATPase. Journal of Biological Chemistry. 2007; 282:10585-10593. © the American Society for Biochemistry and Molecular Biology. Reprinted with permission. All rights reserved. DOI 10.1074/jbc.M609181200