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Distal urinary acidification from Homer Smith to the present
S L Gluck1, M Iyori, L S Holliday
1Department of Medicine, Washington University School of Medicine, St. Louis, Missouri, USA. sgluck@imgate.wustl.edu
Kidney International
|June 1, 1996
Summary
Collecting duct intercalated cells use V-ATPase for acid-base balance. Different cell types regulate this proton pump through structural variations, regulatory proteins, and membrane trafficking for precise control.
Area of Science:
- Nephrology
- Cell Biology
- Physiology
Background:
- Collecting duct intercalated cells are crucial for regulating net acid excretion.
- These cells utilize vacuolar-type H+-ATPase (V-ATPase) for bicarbonate reabsorption, regeneration, and secretion, maintaining acid-base homeostasis.
Observation:
- Intercalated cells employ V-ATPase on their plasma membrane and associated tubulovesicles, distinct from H+-exchange mechanisms.
- Regulation of V-ATPase activity involves multiple mechanisms across different renal cell types.
Findings:
- Renal epithelial cells express diverse V-ATPase structural forms with varying enzymatic properties.
- Cytosolic regulatory proteins interact with V-ATPase, modulating its activity.
- Alpha intercalated cells control luminal V-ATPase via vesicle-mediated traffic, while beta intercalated cells regulate basolateral V-ATPase through assembly/disassembly in response to extracellular pH.
Implications:
- Understanding these regulatory mechanisms is key to comprehending kidney function in acid-base balance.
- Variations in V-ATPase structure and regulation contribute to cell-specific control of proton transport.
- Further research into unidentified mediators of V-ATPase trafficking is warranted.