Reconstitution of cAMP-dependent protein kinase regulated renal Na+-H+ exchanger.

Published

Journal Article

Studies were performed to determine if the Na+-H+ exchanger, solubilized from renal brush border membranes from the rabbit and assayed in reconstituted artificial proteoliposomes, could be regulated by cAMP-dependent protein kinase. Octyl glucoside solubilized renal apical membrane proteins from the rabbit kidney were phosphorylated by incubation with ATP and highly purified catalytic subunit of cAMP-dependent kinase. 22Na+ uptake was determined subsequently after reconstitution of the proteins into proteoliposomes. cAMP-dependent protein kinase resulted in sustained protein phosphorylation and a concentration-dependent decrease in the amiloride-sensitive component of pH gradient-stimulated sodium uptake. The inhibitory effect of cAMP-dependent protein kinase demonstrated an absolute requirement for ATP and was blocked by the specific protein inhibitor of this kinase. cAMP-dependent protein kinase also inhibited 22Na+ uptake in the absence of a pH gradient (pHin 6.0, pHout 6.0) and the inhibitory effect was blocked by the specific inhibitor of the kinase. Solubilized membrane proteins exhibited little endogenous protein kinase or protein phosphatase activity. These studies indicate that Na+-H+ exchange activity of proteoliposomes reconstituted with proteins from renal brush border membranes is inhibited by phosphorylation of selected proteins by cAMP-dependent protein kinase. These findings also indicate that the regulatory components of the Na+-H+ exchanger remain active during the process of solubilization and reconstitution of renal apical membrane proteins.

Full Text

Duke Authors

Cited Authors

  • Weinman, EJ; Dubinsky, WP; Shenolikar, S

Published Date

  • January 1988

Published In

Volume / Issue

  • 101 / 1

Start / End Page

  • 11 - 18

PubMed ID

  • 2835485

Pubmed Central ID

  • 2835485

Electronic International Standard Serial Number (EISSN)

  • 1432-1424

International Standard Serial Number (ISSN)

  • 0022-2631

Digital Object Identifier (DOI)

  • 10.1007/bf01872815

Language

  • eng