Novel role for Na,K-ATPase in phosphatidylinositol 3-kinase signaling and suppression of cell motility

Mol Biol Cell. 2005 Mar;16(3):1082-94. doi: 10.1091/mbc.e04-05-0427. Epub 2004 Dec 22.


The Na,K-ATPase, consisting of alpha- and beta-subunits, regulates intracellular ion homeostasis. Recent studies have demonstrated that Na,K-ATPase also regulates epithelial cell tight junction structure and functions. Consistent with an important role in the regulation of epithelial cell structure, both Na,K-ATPase enzyme activity and subunit levels are altered in carcinoma. Previously, we have shown that repletion of Na,K-ATPase beta1-subunit (Na,K-beta) in highly motile Moloney sarcoma virus-transformed Madin-Darby canine kidney (MSV-MDCK) cells suppressed their motility. However, until now, the mechanism by which Na,K-beta reduces cell motility remained elusive. Here, we demonstrate that Na,K-beta localizes to lamellipodia and suppresses cell motility by a novel signaling mechanism involving a cross-talk between Na,K-ATPase alpha1-subunit (Na,K-alpha) and Na,K-beta with proteins involved in phosphatidylinositol 3-kinase (PI3-kinase) signaling pathway. We show that Na,K-alpha associates with the regulatory subunit of PI3-kinase and Na,K-beta binds to annexin II. These molecular interactions locally activate PI3-kinase at the lamellipodia and suppress cell motility in MSV-MDCK cells, independent of Na,K-ATPase ion transport activity. Thus, these results demonstrate a new role for Na,K-ATPase in regulating carcinoma cell motility.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, U.S. Gov't, Non-P.H.S.
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Actins / chemistry
  • Actins / metabolism
  • Animals
  • Annexin A2 / chemistry
  • Annexin A2 / genetics
  • Cell Line
  • Cell Movement
  • Chromatography, Liquid
  • Chromones / pharmacology
  • Cloning, Molecular
  • Cytoplasm / metabolism
  • Cytoskeleton
  • Dogs
  • Epithelial Cells / cytology
  • Glutathione Transferase / metabolism
  • Immunoblotting
  • Immunoprecipitation
  • Ions
  • Mass Spectrometry
  • Microscopy, Confocal
  • Microscopy, Fluorescence
  • Models, Biological
  • Morpholines / pharmacology
  • Peptide-N4-(N-acetyl-beta-glucosaminyl) Asparagine Amidase / metabolism
  • Phalloidine / pharmacology
  • Phosphatidylinositol 3-Kinases / metabolism*
  • Protein Binding
  • Protein Structure, Tertiary
  • Recombinant Fusion Proteins / metabolism
  • Signal Transduction
  • Sodium-Potassium-Exchanging ATPase / chemistry
  • Sodium-Potassium-Exchanging ATPase / physiology*
  • Tight Junctions
  • rac1 GTP-Binding Protein / metabolism


  • Actins
  • Annexin A2
  • Chromones
  • Ions
  • Morpholines
  • Recombinant Fusion Proteins
  • Phalloidine
  • 2-(4-morpholinyl)-8-phenyl-4H-1-benzopyran-4-one
  • Glutathione Transferase
  • Peptide-N4-(N-acetyl-beta-glucosaminyl) Asparagine Amidase
  • rac1 GTP-Binding Protein
  • Sodium-Potassium-Exchanging ATPase