Nongastric H,K-ATPase: structure and functional properties

Details

Serval ID
serval:BIB_1D66DE2B4EE2
Type
Article: article from journal or magazin.
Collection
Publications
Institution
Title
Nongastric H,K-ATPase: structure and functional properties
Journal
Annals of the New York Academy of Sciences
Author(s)
Modyanov  N., Pestov  N., Adams  G., Crambert  G., Tillekeratne  M., Zhao  H., Korneenko  T., Shakhparonov  M., Geering  K.
ISSN
0077-8923 (Print)
Publication state
Published
Issued date
04/2003
Volume
986
Pages
183-7
Notes
Journal Article
Research Support, Non-U.S. Gov't
Research Support, U.S. Gov't, P.H.S. --- Old month value: Apr
Abstract
Nongastric H,K-ATPases whose catalytic subunits (AL1) encoded by human ATP1AL1 and homologous animal genes comprise the third distinct group within the X,K-ATPase family. No unique nongastric beta has been identified. Precise in situ colocalization and strong association of AL1 with beta1 of Na,K-ATPase was detected in apical membranes of rodent prostate epithelium. In this tissue, beta1NK serves as an authentic subunit of both the Na,K- and nongastric H,K-pumps. Upon expression in Xenopus oocytes the human AL1 can assemble with beta1NK, and more efficiently with gastric betaHK, into functional H,K-pumps. Both AL1/beta complexes exhibit a similar K-affinity, and their K-transport depends on intra- and extracellular Na. These data provide new evidence that nongastric H,K-ATPase can perform Na/K-exchange, and indicate that beta does not significantly affect this ion-pump function. Analysis of human nongastric H,K-ATPase expressed in Sf-21 insect cells revealed that AL1/betaHK exhibits substantial enzymatic activities in K-free medium and K stimulates, but Na has inhibitory effect on ATP hydrolysis. Thus, although the nongastric H,K-ATPase can function as Na/K exchanger, its reaction mechanism is different from that of the Na,K-ATPase. Human nongastric H,K-ATPase is highly sensitive to bufalin, digoxin, and digitoxin, but almost resistant to digoxigenin and ouabagenin.
Keywords
Animals Cell Membrane/enzymology Epithelial Cells/enzymology H(+)-K(+)-Exchanging ATPase/*chemistry/*metabolism Humans Ions/metabolism Male Oocytes/enzymology Prostate/cytology/enzymology Protein Subunits/chemistry/metabolism Xenopus
Pubmed
Web of science
Create date
24/01/2008 12:28
Last modification date
20/08/2019 12:53
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