Na,K-ATPase beta1-subunit increases the translation efficiency of the alpha1-subunit in MSV-MDCK cells. Academic Article uri icon

Overview

abstract

  • 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 date

  • May 7, 2004

Research

keywords

  • Gene Expression Regulation, Enzymologic
  • Protein Biosynthesis
  • Protein Subunits
  • Sodium-Potassium-Exchanging ATPase

Identity

PubMed Central ID

  • PMC452578

Scopus Document Identifier

  • 3042724904

Digital Object Identifier (DOI)

  • 10.1091/mbc.e04-03-0222

PubMed ID

  • 15133131

Additional Document Info

volume

  • 15

issue

  • 7