Mechanisms of urinary K+ and H+ excretion: primary structure and functional expression of a novel H,K-ATPase
Details
Serval ID
serval:BIB_473E499CA107
Type
Article: article from journal or magazin.
Collection
Publications
Institution
Title
Mechanisms of urinary K+ and H+ excretion: primary structure and functional expression of a novel H,K-ATPase
Journal
Journal of Cell Biology
ISSN
0021-9525 (Print)
Publication state
Published
Issued date
12/1993
Volume
123
Number
6 Pt 1
Pages
1421-9
Notes
Comparative Study
Journal Article
Research Support, Non-U.S. Gov't --- Old month value: Dec
Journal Article
Research Support, Non-U.S. Gov't --- Old month value: Dec
Abstract
The kidney plays an essential role in regulating potassium and acid balance. A major site for these regulations is in the collecting tubule. In the present study, we report the primary sequence of a novel alpha subunit of the P-ATPase gene family, which we isolated from the urinary bladder epithelium of the toad Bufo marinus, the amphibian equivalent of the mammalian collecting tubule. The cDNA encodes a protein of 1,042 amino acids which shares approximately 67% identity with the alpha 1 subunit of the ouabain-inhibitable Na,K-ATPase and approximately 69% identity with the alpha subunit of the SCH28080-inhibitable gastric H,K-ATPase. When coexpressed in Xenopus oocytes with a beta subunit isolated from the same cDNA library, the ATPase is able to transport rubidium (a potassium surrogate) inward, and hydrogen outward, leading to alkalization of the intracellular compartment and acidification of the external medium. The novel ATPase has a unique pharmacological profile showing intermediate sensitivity to both ouabain and SCH28080. Our findings indicate that the bladder ATPase is a member of a new ion motive P-ATPase subfamily. The bladder ATPase is expressed in the urinary tract but not in the stomach or the colon. This H,K-ATPase may be one of the molecules involved in H+ and K+ homeostasis, mediating the transport of these ions across urinary epithelia and therefore regulating their urinary excretion.
Keywords
Amino Acid Sequence
Animals
Base Sequence
Bufo marinus
Cloning, Molecular
DNA Primers/chemistry
Gene Expression
H(+)-K(+)-Exchanging ATPase/chemistry/*metabolism
Hydrogen-Ion Concentration
Imidazoles/metabolism
Kidney/enzymology
Molecular Sequence Data
Multigene Family
Ouabain/metabolism
Potassium/*urine
Protein Binding
RNA, Messenger/genetics
Rats
Sequence Alignment
Sequence Homology, Amino Acid
Tissue Distribution
Urinary Bladder/enzymology
Pubmed
Web of science
Open Access
Yes
Create date
24/01/2008 13:28
Last modification date
20/08/2019 14:53