The beta subunit modulates potassium activation of the Na-K pump

Details

Serval ID
serval:BIB_E02FAF341E5B
Type
Article: article from journal or magazin.
Collection
Publications
Institution
Title
The beta subunit modulates potassium activation of the Na-K pump
Journal
Annals of the New York Academy of Sciences
Author(s)
Jaisser  F., Horisberger  J. D., Rossier  B. C.
ISSN
0077-8923 (Print)
Publication state
Published
Issued date
11/1992
Volume
671
Pages
113-9
Notes
Journal Article
Research Support, Non-U.S. Gov't --- Old month value: Nov 30
Abstract
We recently cloned the alpha 1 and the beta 1 and beta 3 subunits of the Na,K-ATPase of the toad Bufo marinus. To investigate possible functional differences between beta 1 and beta 3, we studied the potassium activation of Na-K pumps expressed in the oocyte of Xenopus laevis. Na-K pump activity was measured as K(+)-induced current in voltage-clamped oocytes. We could take advantage of the relative resistance to ouabain conferred by the Bufo alpha subunit to study specifically the exogenously expressed Na-K pumps after inhibition of the ouabain-sensitive endogenous Xenopus Na-K pumps. Coinjection of Bufo alpha 1 subunit cRNA with either beta 1 or beta 3 cRNAs results in the expression of functional Na-K pumps that share similar low ouabain sensitivity but differ in their K+ half activation constant (K1/2). Similar results were obtained with Xenopus alpha 1 and beta 1 or beta 3 subunits and with Bufo/Xenopus heterodimers. We conclude that some specific sequence of the beta subunit can influence the activation of the Na,K pump by extracellular K+ ions.
Keywords
Animals Bufo marinus Enzyme Activation Kinetics Macromolecular Substances Na(+)-K(+)-Exchanging ATPase/drug effects/*metabolism/*physiology Ouabain/pharmacology Potassium/*metabolism/pharmacology Xenopus laevis
Pubmed
Create date
24/01/2008 12:38
Last modification date
20/08/2019 16:04
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