Nongastric H,K-ATPase: structure and functional properties
Détails
ID Serval
serval:BIB_1D66DE2B4EE2
Type
Article: article d'un périodique ou d'un magazine.
Collection
Publications
Institution
Titre
Nongastric H,K-ATPase: structure and functional properties
Périodique
Annals of the New York Academy of Sciences
ISSN
0077-8923 (Print)
Statut éditorial
Publié
Date de publication
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
Research Support, Non-U.S. Gov't
Research Support, U.S. Gov't, P.H.S. --- Old month value: Apr
Résumé
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.
Mots-clé
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
Création de la notice
24/01/2008 13:28
Dernière modification de la notice
20/08/2019 13:53