N-myc downstream-regulated gene 2, a novel estrogen-targeted gene, is involved in the regulation of Na+/K+-ATPase

J Biol Chem. 2011 Sep 16;286(37):32289-99. doi: 10.1074/jbc.M111.247825. Epub 2011 Jul 19.

Abstract

Na(+)/K(+)-ATPase, a plasma membrane protein abundantly expressed in epithelial tissues, has been identified and linked to numerous biological events, including ion transport and reabsorption. In Na(+)/K(+)-ATPase, the β-subunit plays a fundamental role in the structural integrity and functional maturation of holoenzyme. Estrogens are important circulating hormones that can regulate Na(+)/K(+)-ATPase abundance and activity; however, the specific molecules participating in this process are largely unknown. Here, we characterize that N-myc downstream-regulated gene 2 (NDRG2) is an estrogen up-regulated gene. 17β-Estradiol binds with estrogen receptor β but not estrogen receptor α to up-regulate NDRG2 expression via transcriptional activation. We also find that NDRG2 interacts with the β1-subunit of Na(+)/K(+)-ATPase and stabilizes the β1-subunit by inhibiting its ubiquitination and degradation. NDRG2-induced prolongation of the β1-subunit protein half-life is accompanied by a similar increase in Na(+)/K(+)-ATPase-mediated Na(+) transport and Na(+) current in epithelial cells. In addition, NDRG2 silencing largely attenuates the accumulation of β1-subunit regulated by 17β-estradiol. Our results demonstrate that estrogen/NDRG2/Na(+)/K(+)-ATPase β1 pathway is important in promoting Na(+)/K(+)-ATPase activity and suggest this novel pathway might have substantial roles in ion transport, fluid balance, and homeostasis.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Estradiol / pharmacology*
  • Estrogen Receptor beta / genetics
  • Estrogen Receptor beta / metabolism
  • Estrogens / pharmacology*
  • HeLa Cells
  • Homeostasis / drug effects
  • Homeostasis / physiology
  • Humans
  • Ion Transport / drug effects
  • Ion Transport / physiology
  • Sodium / metabolism
  • Sodium-Potassium-Exchanging ATPase / biosynthesis*
  • Sodium-Potassium-Exchanging ATPase / genetics
  • Transcription, Genetic / drug effects*
  • Transcription, Genetic / physiology
  • Tumor Suppressor Proteins / genetics
  • Tumor Suppressor Proteins / metabolism*
  • Up-Regulation / drug effects*
  • Up-Regulation / physiology

Substances

  • Estrogen Receptor beta
  • Estrogens
  • NDRG2 protein, human
  • Tumor Suppressor Proteins
  • Estradiol
  • Sodium
  • Sodium-Potassium-Exchanging ATPase