The nucleolar protein Esf2 interacts directly with the DExD/H box RNA helicase, Dbp8, to stimulate ATP hydrolysis

Nucleic Acids Res. 2006 Jun 13;34(10):3189-99. doi: 10.1093/nar/gkl419. Print 2006.

Abstract

While 18 putative RNA helicases are involved in ribosome biogenesis in Saccharomyces cerevisiae, their enzymatic properties have remained largely biochemically uncharacterized. To better understand their function, we examined the enzymatic properties of Dpb8, a DExD/H box protein previously shown to be required for the synthesis of the 18S rRNA. As expected for an RNA helicase, we demonstrate that recombinant Dbp8 has ATPase activity in vitro, and that this activity is dependent on an intact ATPase domain. Strikingly, we identify Esf2, a nucleolar putative RNA binding protein, as a binding partner for Dbp8, and show that it enhances Dbp8 ATPase activity by decreasing the K(M) for ATP. Thus, we have uncovered Esf2 as the first example of a protein co-factor that has a stimulatory effect on a nucleolar RNA helicase. We show that Esf2 can bind to pre-rRNAs and speculate that it may function to bring Dbp8 to the pre-rRNA, thereby both regulating its enzymatic activity and guiding Dbp8 to its site of action.

Publication types

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

MeSH terms

  • Adenosine Triphosphatases / chemistry
  • Adenosine Triphosphatases / metabolism
  • Adenosine Triphosphate / metabolism*
  • Amino Acid Motifs
  • DEAD-box RNA Helicases
  • Hydrolysis
  • Nuclear Proteins / chemistry
  • Nuclear Proteins / metabolism*
  • Protein Structure, Tertiary
  • RNA Helicases / chemistry
  • RNA Helicases / metabolism*
  • RNA, Ribosomal / chemistry
  • RNA, Ribosomal / metabolism
  • Saccharomyces cerevisiae Proteins / chemistry
  • Saccharomyces cerevisiae Proteins / metabolism*

Substances

  • Esf2 protein, S cerevisiae
  • Nuclear Proteins
  • RNA, Ribosomal
  • Saccharomyces cerevisiae Proteins
  • Adenosine Triphosphate
  • Adenosine Triphosphatases
  • DBP8 protein, S cerevisiae
  • DEAD-box RNA Helicases
  • RNA Helicases