Na,K-ATPase beta1-subunit increases the translation efficiency of the alpha1-subunit in MSV-MDCK cells

Mol Biol Cell. 2004 Jul;15(7):3224-32. doi: 10.1091/mbc.e04-03-0222. Epub 2004 May 7.


The Na,K-ATPase consists of an alpha- and beta-subunit. Moloney sarcoma virus-transformed MDCK cells (MSV-MDCK) express low levels of Na,K-ATPase beta(1)-subunit. Ectopic expression of Na,K-ATPase beta(1)-subunit in these cells increased the protein levels of the alpha(1)-subunit of Na,K-ATPase. This increase was not due to altered transcription of the alpha(1)-subunit gene or half-life of the alpha(1)-subunit protein because both alpha(1)-subunit mRNA levels and half-life of the alpha(1)-subunit protein were comparable in MSV-MDCK and beta(1)-subunit expressing MSV-MDCK cells. However, short pulse labeling revealed that the initial translation rate of the alpha(1)-subunit in beta(1)-subunit expressing MSV-MDCK cells was six- to sevenfold higher compared with MSV-MDCK cells. The increased translation was specific to alpha(1)-subunit because translation rates of occludin and beta-catenin, membrane and cytosolic proteins, respectively, were not altered. In vitro cotranslation/translocation experiments using rabbit reticulocyte lysate and rough microsomes revealed that the alpha(1)-subunit mRNA is more efficiently translated in the presence of beta(1)-subunit. Furthermore, sucrose density gradient analysis revealed significantly more alpha(1)-subunit transcript associated with the polysomal fraction in beta(1)-subunit expressing MSV-MDCK cells compared with MSV-MDCK cells, indicating that in mammalian cells the Na,K-ATPase beta(1)-subunit is involved in facilitating the translation of the alpha(1)-subunit mRNA in the endoplasmic reticulum.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Cell Extracts / chemistry
  • Cell Line, Transformed
  • Cell Membrane / chemistry
  • Dogs
  • Gene Expression Regulation, Enzymologic*
  • Moloney murine sarcoma virus / metabolism
  • Polyribosomes / chemistry
  • Polyribosomes / metabolism
  • Protein Biosynthesis*
  • Protein Subunits / analysis
  • Protein Subunits / biosynthesis
  • Protein Subunits / genetics
  • Protein Subunits / metabolism
  • Protein Subunits / physiology*
  • RNA, Messenger / analysis
  • RNA, Messenger / metabolism
  • Sodium-Potassium-Exchanging ATPase / analysis
  • Sodium-Potassium-Exchanging ATPase / metabolism
  • Sodium-Potassium-Exchanging ATPase / physiology*
  • Up-Regulation


  • Cell Extracts
  • Protein Subunits
  • RNA, Messenger
  • Sodium-Potassium-Exchanging ATPase