Regulation of Na/K-ATPase expression by cholesterol: isoform specificity and the molecular mechanism. Am J Physiol Cell Physiol 2020 Dec 01;319(6):C1107-C1119
Date
10/01/2020Pubmed ID
32997514Pubmed Central ID
PMC7792677DOI
10.1152/ajpcell.00083.2020Scopus ID
2-s2.0-85098226317 (requires institutional sign-in at Scopus site) 5 CitationsAbstract
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.
Author List
Zhang J, Li X, Yu H, Larre I, Dube PR, Kennedy DJ, Tang WHW, Westfall K, Pierre SV, Xie Z, Chen YAuthor
Yiliang Chen PhD Assistant Professor in the Medicine department at Medical College of WisconsinMESH terms used to index this publication - Major topics in bold
AndrostenesAnimals
Anticholesteremic Agents
Caveolin 1
Cell Line
Cell Membrane
Cholesterol
Isoenzymes
Liver
Rats
Signal Transduction
Sodium-Potassium-Exchanging ATPase
Swine
src-Family Kinases
