Regulation of renal Na(+)-H+ exchanger by cAMP-dependent protein kinase.
Octyl glucoside-extracted rabbit renal brush-border membrane (BBM) proteins were sequentially fractionated using anion exchange chromatography, and the fractions were tested for Na(+)-H+ exchange activity, amiloride sensitivity, and the effect of adenosine 3',5'-cyclic monophosphate (cAMP)-dependent protein kinase (PKA) after reconstitution into artificial lipid vesicles. Compared with the initial protein extract, an anionic protein fraction eluting with 0.2-0.4 M NaCl (fraction B) demonstrated increased Na(+)-H+ exchange activity. Fraction B also demonstrated sensitivity to inhibition by amiloride but was not regulated by PKA. Co-reconstitution of fraction B with a BBM protein fraction highly enriched in a 42-kDa polypeptide restored the inhibitory response to PKA. These experiments suggest that, as assayed in a solubilized and reconstituted system, the Na(+)-H+ exchanger contains a dissociable PKA regulatory component, possibly a polypeptide of 42 kDa.
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Related Subject Headings
- Sodium-Hydrogen Exchangers
- Sodium
- Proteins
- Protein Kinases
- Phosphorylation
- Microvilli
- Liposomes
- Kidney
- Hydrogen-Ion Concentration
- Electrophoresis, Polyacrylamide Gel
Citation
Published In
DOI
ISSN
Publication Date
Volume
Issue
Start / End Page
Location
Related Subject Headings
- Sodium-Hydrogen Exchangers
- Sodium
- Proteins
- Protein Kinases
- Phosphorylation
- Microvilli
- Liposomes
- Kidney
- Hydrogen-Ion Concentration
- Electrophoresis, Polyacrylamide Gel