Na,K-ATPase α1-subunit dephosphorylation by protein phosphatase 2A is necessary for its recruitment to the plasma membrane

Emilia Lecuona*, Laura Dada, Haiying Sun, Maria L. Butti, Guofei Zhou, Teng Leong Chew, Jacob I Sznajder

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

38 Scopus citations

Abstract

In alveolar epithelial cells, G-protein coupled-receptors agonists (GPCR) induce the recruitment of the Na,K-ATPase to the plasma membrane. Here we report that for the recruitment of the Na,K-ATPase to occur, dephosphorylation of its α1-subunit at serine 18 is necessary, as demonstrated by in vitro phosphorylation, mutation of the serine 18 to alanine, and use of a specific phospho-antibody. Several approaches strongly suggest dephosphorylation to be mediated by protein phosphatase 2A (PP2A): 1) Na,K-ATPase dephosphorylation and recruitment were prevented by okadaic acid (OA); 2) the Na,K-ATPase α1-subunit is an in vitro substrate for PP2A; and 3) glutathione S-transferase (GST)-fusion proteins binding assays demonstrate a direct interaction between the catalytic subunit of PP2A and the first 90 amino acids of the Na,K-ATPase α1-subunit. Finally, GPCR agonists induced a rapid translocation of PP2A from the cytosol to the membrane fraction, which corresponded with increased coimmunoprecipitation and colocalization of PP2A and the Na,K-ATPase. Accordingly, we provide evidence that GPCR agonists promote PP2A translocation to the membrane fraction, leading to the dephosphorylation of the Na,K-ATPase α1-subunit at the serine 18 residue and its recruitment to the cell plasma membrane, which is of biological and physiological importance.

Original languageEnglish (US)
Pages (from-to)E2146-E2155
JournalFASEB Journal
Volume20
Issue number14
DOIs
StatePublished - Dec 2006

Keywords

  • Alveolar epithelial cells
  • G-protein-coupled receptor agonists
  • Intracellular trafficking

ASJC Scopus subject areas

  • Biotechnology
  • Biochemistry
  • Molecular Biology
  • Genetics

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