Serum-deprivation stimulates cap-binding by PARN at the expense of eIF4E, consistent with the observed decrease in mRNA stability

  1. Lookup NU author(s)
  2. Dr Richard Temperley
  3. Professor Robert Lightowlers
  4. Professor Zofia Chrzanowska-Lightowlers
Author(s)Seal R, Temperley RJ, Wilusz J, Lightowlers RN, Chrzanowska-Lightowlers ZMA
Publication type Article
JournalNucleic Acids Research
ISSN (print)0305-1048
ISSN (electronic)1362-4954
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PARN, a poly(A)-specific ribonuclease, binds the 5' cap-structure of mRNA and initiates deadenylation-dependent decay. Eukaryotic initiation factor 4E (eIF4E) also binds to the cap structure, an interaction that is critical for initiating cap-dependent translation. The stability of various mRNA transcripts in human cell lines is reduced under conditions of serum starvation as determined by both functional and chemical half-lives. Serum starvation also leads to enhanced cap association by PARN. In contrast, the 5' cap occupancy by eIF4E decreases under serum-deprivation, as does the translation of reporter transcripts. Further, we show that PARN is a phosphoprotein and that this modification can be modulated by serum status. Taken together, these data are consistent with a natural competition existing at the 5' cap structure between PARN and eIF4E that may be regulated by changes in post-translational modifications. These phosphorylation-induced changes in the interplay of PARN and eIF4E may determine whether the mRNA is translated or decayed.
PublisherOxford University Press
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