Bufo marinus bladder H-K-ATPase carries out electroneutral ion transport
Details
Serval ID
serval:BIB_DAAF2C60C5E0
Type
Article: article from journal or magazin.
Collection
Publications
Institution
Title
Bufo marinus bladder H-K-ATPase carries out electroneutral ion transport
Journal
American Journal of Physiology. Renal Physiology
ISSN
0363-6127 (Print)
Publication state
Published
Issued date
11/2001
Volume
281
Number
5
Pages
F869-74
Notes
Journal Article
Research Support, Non-U.S. Gov't --- Old month value: Nov
Research Support, Non-U.S. Gov't --- Old month value: Nov
Abstract
Bufo marinus bladder H-K-ATPase belongs to the Na-K-ATPase and H-K-ATPase subfamily of oligomeric P-type ATPases and is closely related to rat and human nongastric H-K-ATPases. It has been demonstrated that this ATPase transports K(+) into the cell in exchange for protons and sodium ions, but the stoichiometry of this cation exchange is not yet known. We studied the electrogenic properties of B. marinus bladder H-K-ATPase expressed in Xenopus laevis oocytes. In a HEPES-buffered solution, K(+) activation of the H-K-ATPase induced a slow-onset inward current that reached an amplitude of approximately 20 nA after 1-2 min. When measurements were performed in a solution containing 25 mM HCO at a PCO(2) of 40 Torr, the negative current activated by K(+) was reduced. In noninjected oocytes, intracellular alkalization activated an inward current similar to that due to B. marinus H-K-ATPase. We conclude that the transport activity of the nongastric B. marinus H-K-ATPase is not intrinsically electrogenic but that the inward current observed in oocytes expressing this ion pump is secondary to intracellular alkalization induced by proton transport.
Keywords
4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid/pharmacology
Animals
Bicarbonates/pharmacology
Biological Transport
*Bufo marinus
Carbon Dioxide/pharmacology
Electric Conductivity
Female
Gene Expression
H(+)-K(+)-Exchanging ATPase/genetics/*metabolism
Hydrogen-Ion Concentration
Membrane Potentials
Na(+)-K(+)-Exchanging ATPase/metabolism
Oocytes/metabolism
Rubidium Radioisotopes/metabolism
Transfection
Urinary Bladder/*enzymology
Xenopus laevis
Pubmed
Web of science
Create date
24/01/2008 13:28
Last modification date
20/08/2019 16:59