Renal expression of the gene encoding the gastric H(+)-K(+)-ATPase beta-subunit.
The gastric mucosal parietal cells and cells of the renal collecting duct both possess H(+)-K(+)-adenosinetriphosphatase (H(+)-K(+)-ATPase) activities. In the stomach, the H(+)-K(+)-ATPase (EC 3.6.1.3) is responsible for acidification of luminal contents. The kidney H(+)-K(+)-ATPase protein(s) contribute to potassium reabsorption and secretion of hydrogen ions to maintain potassium and acid-base homeostasis. The stomach H(+)-K(+)-ATPase is well defined and consists of an alpha-catalytic subunit of apparent molecular mass of 95 kDa and a highly glycosylated beta-subunit of 60-90 kDa. The molecular identity of the protein that mediates the H(+)-K(+)-ATPase activity in the kidney has been addressed in this paper. A combination of RNA hybridizations, polymerase chain reaction analysis of kidney RNA, and sequence analysis of cDNAs indicated that gastric H(+)-K(+)-ATPase beta-subunit mRNA is present in kidney. Immunoblotting with antibodies specific for the gastric H(+)-K(+)-ATPase beta-subunit detected proteins, which, after deglycosylation, had the same molecular mass as the gastric beta-subunit in membrane protein preparations from rabbit, pig, rat, and mouse kidneys. Furthermore, we have used transgenic mice to demonstrate that the gastric H(+)-K(+)-ATPase beta-subunit gene contains cis-acting regulatory sequences that are active in both gastric parietal cells and the renal collecting ducts. Overall, these data indicate that the gastric H(+)-K(+)-ATPase beta-subunit is found in the kidney and probably associates with the gastric H(+)-K(+)-ATPase alpha-subunit and/or other P-type ATPase alpha-subunits, thus contributing to acid-base and potassium homeostasis.
Callaghan
J M
JM
Department of Pathology and Immunology, Monash University Medical School, Alfred Hospital, Prahran, Melbourne, Australia.
Tan
S S
SS
Khan
M A
MA
Curran
K A
KA
Campbell
W G
WG
Smolka
A J
AJ
Toh
B H
BH
Gleeson
P A
PA
Wingo
C S
CS
Cain
B D
BD
D000818:Animals; D000911:Antibodies, Monoclonal; D001483:Base Sequence; D018076:DNA, Complementary / Q000235:genetics; D005753:Gastric Mucosa / Q000201:enzymology; D015870:Gene Expression; D005809:Genes, Regulator; D017506:H(+)-K(+)-Exchanging ATPase / Q000737:chemistry / Q000235:genetics* / Q000276:immunology; D007150:Immunohistochemistry; D007668:Kidney / Q000201:enzymology*; D051379:Mice; D008822:Mice, Transgenic; D008969:Molecular Sequence Data; D016133:Polymerase Chain Reaction; D011487:Protein Conformation; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D011817:Rabbits; D013552:Swine
D000911:Antibodies, Monoclonal; D018076:DNA, Complementary; D012333:RNA, Messenger; D017506:H(+)-K(+)-Exchanging ATPase