HuR stabilizes vacuolar H+-translocating ATPase mRNA during cellular energy depletion

J Biol Chem. 2005 Nov 11;280(45):37957-64. doi: 10.1074/jbc.M502883200. Epub 2005 Sep 9.

Abstract

V-ATPases are multisubunit membrane proteins that use ATP binding and hydrolysis to transport protons across membranes against a concentration gradient. Although some cell types express plasma membrane forms of these transporters, all eukaryotes require V-ATPases to maintain an acidic pH in membrane-bound compartments of endocytic and secretory networks to facilitate protein trafficking and processing. Mammalian cells that completely lack V-ATPases are not viable; yet, the abundance of V-ATPases can differ among cell types by an order of magnitude or more, requiring precise control of their expression. We previously showed that mRNA stability appears to play a major role in regulating overall abundance of V-ATPases. In this report, we demonstrate that the stability of V-ATPase mRNA is regulated through AU-rich elements in 3'-untranslated regions. Unlike some mRNAs that are short-lived due to the presence of these elements, V-ATPase mRNAs have half-lives of hours to days. However, during stress induced by ATP depletion, AU-rich elements are necessary to maintain stability of these transcripts and their presence in the cytoplasm. HuR, an RNA-binding protein that interacts with and stabilizes AU-rich mRNAs, shows increased binding to some V-ATPase mRNAs during ATP depletion. siRNA-mediated knockdown of HuR results in diminished V-ATPase expression. These results indicate that AU-rich elements and associated proteins can play a role in regulation of even very stable mRNAs by protecting against loss during cellular stress.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • AT Rich Sequence / genetics
  • Adenosine Triphosphate / metabolism*
  • Amino Acid Sequence
  • Animals
  • Antigens, Surface / metabolism*
  • Cell Line
  • ELAV Proteins
  • ELAV-Like Protein 1
  • Energy Metabolism
  • Humans
  • RNA Interference
  • RNA Stability
  • RNA, Messenger / genetics
  • RNA, Messenger / metabolism
  • RNA, Small Interfering / genetics
  • RNA, Small Interfering / metabolism
  • RNA-Binding Proteins / metabolism*
  • Vacuolar Proton-Translocating ATPases / genetics*
  • Vacuolar Proton-Translocating ATPases / metabolism*

Substances

  • Antigens, Surface
  • ELAV Proteins
  • ELAV-Like Protein 1
  • ELAVL1 protein, human
  • RNA, Messenger
  • RNA, Small Interfering
  • RNA-Binding Proteins
  • Adenosine Triphosphate
  • ATP6V1E2 protein, human
  • Vacuolar Proton-Translocating ATPases