Regulation of Na/K-ATPase expression by cholesterol: isoform specificity and the molecular mechanism

Am J Physiol Cell Physiol. 2020 Dec 1;319(6):C1107-C1119. doi: 10.1152/ajpcell.00083.2020. Epub 2020 Sep 30.


We have reported that the reduction in plasma membrane cholesterol could decrease cellular Na/K-ATPase α1-expression through a Src-dependent pathway. However, it is unclear whether cholesterol could regulate other Na/K-ATPase α-isoforms and the molecular mechanisms of this regulation are not fully understood. Here we used cells expressing different Na/K-ATPase α isoforms and found that membrane cholesterol reduction by U18666A decreased expression of the α1-isoform but not the α2- or α3-isoform. Imaging analyses showed the cellular redistribution of α1 and α3 but not α2. Moreover, U18666A led to redistribution of α1 to late endosomes/lysosomes, while the proteasome inhibitor blocked α1-reduction by U18666A. These results suggest that the regulation of the Na/K-ATPase α-subunit by cholesterol is isoform specific and α1 is unique in this regulation through the endocytosis-proteasome pathway. Mechanistically, loss-of-Src binding mutation of A425P in α1 lost its capacity for regulation by cholesterol. Meanwhile, gain-of-Src binding mutations in α2 partially restored the regulation. Furthermore, through studies in caveolin-1 knockdown cells, as well as subcellular distribution studies in cell lines with different α-isoforms, we found that Na/K-ATPase, Src, and caveolin-1 worked together for the cholesterol regulation. Taken together, these new findings reveal that the putative Src-binding domain and the intact Na/K-ATPase/Src/caveolin-1 complex are indispensable for the isoform-specific regulation of Na/K-ATPase by cholesterol.

Keywords: Na/K-ATPase isoforms; Src-binding domain; caveolin-1; cholesterol.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Androstenes / pharmacology
  • Animals
  • Anticholesteremic Agents / pharmacology
  • Caveolin 1 / genetics
  • Caveolin 1 / metabolism*
  • Cell Line
  • Cell Membrane / metabolism
  • Cholesterol / metabolism*
  • Isoenzymes / metabolism
  • Liver / metabolism
  • Rats
  • Signal Transduction / physiology
  • Sodium-Potassium-Exchanging ATPase / metabolism*
  • Swine
  • src-Family Kinases / metabolism


  • Androstenes
  • Anticholesteremic Agents
  • Cav1 protein, rat
  • Caveolin 1
  • Isoenzymes
  • 3-beta-(2-(diethylamino)ethoxy)androst-5-en-17-one
  • Cholesterol
  • src-Family Kinases
  • Sodium-Potassium-Exchanging ATPase