Selective assembly of V-ATPase subunit isoforms in mouse kidney.
The kidney plays vital roles in acid-base homeostasis, and the reabsorption of water, ions, and proteins. These processes are achieved through acidification of urine and endosomes of proximal tubule epithelial cells. Multisubunit vacuolar-type proton ATPase (V-ATPase) is one of the major acidification-machinery proteins that localizes to the apical or basolateral plasma membranes of intercalated cells in collecting ducts and the endosomal region at the base of brush border microvilli in proximal tubules. Multiple subunit isoforms of V-ATPase, which are expressed in kidney, have been identified. One obvious question is whether the pumps at different locations in the kidney have their own unique subunit identities. We have used a combination of methods to study this enzyme in kidney including immunocytochemical staining and immunoprecipitation analyses. The subunit isoforms of V-ATPase exhibited selective association/assembly in kidney: kidney-specific isoforms predominantly formed the intercalated cell proton pump, whereas the pump located in the brush border comprised ubiquitously expressed counterparts.
Sun-Wada
Ge-Hong
GH
Department of Biochemistry, Faculty of Pharmaceutical Sciences, Doshisha Women's College, Kyoto, Japan. kwada@dwc.doshisha.ac.jp
Tabata
Hiroyuki
H
Kawamura
Nobuyuki
N
D000818:Animals; D007668:Kidney / Q000201:enzymology* / Q000378:metabolism; D007684:Kidney Tubules / Q000166:cytology / Q000201:enzymology; D051379:Mice; D008871:Microvilli / Q000201:enzymology; D020033:Protein Isoforms / Q000032:analysis; D021122:Protein Subunits / Q000032:analysis; D014018:Tissue Distribution; D025262:Vacuolar Proton-Translocating ATPases / Q000032:analysis / Q000096:biosynthesis*
D020033:Protein Isoforms; D021122:Protein Subunits; D025262:Vacuolar Proton-Translocating ATPases