The Drosophila deoxyhypusine hydroxylase homologue nero and its target eIF5A are required for cell growth and the regulation of autophagy

J Cell Biol. 2009 Jun 29;185(7):1181-94. doi: 10.1083/jcb.200904161. Epub 2009 Jun 22.

Abstract

Hypusination is a unique posttranslational modification by which lysine is transformed into the atypical amino acid hypusine. eIF5A (eukaryotic initiation factor 5A) is the only known protein to contain hypusine. In this study, we describe the identification and characterization of nero, the Drosophila melanogaster deoxyhypusine hydroxylase (DOHH) homologue. nero mutations affect cell and organ size, bromodeoxyuridine incorporation, and autophagy. Knockdown of the hypusination target eIF5A via RNA interference causes phenotypes similar to nero mutations. However, loss of nero appears to cause milder phenotypes than loss of eIF5A. This is partially explained through a potential compensatory mechanism by which nero mutant cells up-regulate eIF5A levels. The failure of eIF5A up-regulation to rescue nero mutant phenotypes suggests that hypusination is required for eIF5A function. Furthermore, expression of enzymatically impaired forms of DOHH fails to rescue nero clones, indicating that hypusination activity is important for nero function. Our data also indicate that nero and eIF5A are required for cell growth and affect autophagy and protein synthesis.

Publication types

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

MeSH terms

  • Animals
  • Animals, Genetically Modified
  • Autophagy / physiology*
  • Cell Cycle / physiology
  • Cell Growth Processes / physiology*
  • Drosophila Proteins / genetics
  • Drosophila Proteins / metabolism
  • Drosophila melanogaster / anatomy & histology
  • Drosophila melanogaster / enzymology*
  • Drosophila melanogaster / genetics
  • Gene Knockdown Techniques
  • Mixed Function Oxygenases / chemistry*
  • Mixed Function Oxygenases / genetics
  • Mixed Function Oxygenases / metabolism*
  • Peptide Initiation Factors / genetics
  • Peptide Initiation Factors / metabolism*
  • Phenotype
  • Protein Processing, Post-Translational
  • RNA Interference
  • RNA-Binding Proteins / genetics
  • RNA-Binding Proteins / metabolism*
  • Recombinant Fusion Proteins / genetics
  • Recombinant Fusion Proteins / metabolism

Substances

  • Drosophila Proteins
  • Peptide Initiation Factors
  • RNA-Binding Proteins
  • Recombinant Fusion Proteins
  • eukaryotic translation initiation factor 5A
  • Mixed Function Oxygenases
  • deoxyhypusine hydroxylase