Na+-K+-ATPase in frog esophagus mucociliary cell membranes: Inhibition by protein kinase C activation

Irena Gertsberg, Irena Brodsky, Zvi Priel, Michael Danilenko

Research output: Contribution to journalArticlepeer-review

4 Scopus citations

Abstract

We examined protein kinase C (PKC)-dependent regulation of Na+-K+- ATPase in frog mucociliary cells. Activation of PKC by 12-O- tetradecanoylphorbol-13-acetate (TPA) or 1,2-dioctanoyl-sn-glycerol (diC8) either in intact cells or isolated membranes resulted in a specific inhibition of Na+-K+ATPase activity by ~25-45%. The inhibitory effects in membranes exhibited time dependence and dose dependence [half-maximal inhibition concentration (IC50) = 0.5 ± 0.1 nM and 2.4 ± 0.2 μM, respectively, for TPA and diC8] and were not influenced by Ca2+. Analysis of the ouabain inhibition pattern revealed the presence of two Na+-K+- ATPase isoforms with IC50 values for cardiac glycoside of 2.6 ± 0.8 nM and 409 ± 65 nM, respectively. Most importantly, the isoform possessing a higher affinity for ouabain was almost completely inhibited by TPA, whereas its counterpart was hardly sensitive to the PKC activator. The results suggest that, in frog mucociliary cells, PKC regulates Na+-K+-ATPase and that this action is related to the specific Na+-K+-ATPase isoform.

Original languageEnglish
Pages (from-to)C1842-C1848
JournalAmerican Journal of Physiology - Cell Physiology
Volume273
Issue number6 42-6
DOIs
StatePublished - 1 Jan 1997

Keywords

  • Ouabain
  • Phorbol esters
  • Sodium-potassium-adenosinetriphosphatase isoforms

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