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Nucleic Acids Res. 2005 Jan 14;33(1):376-87. Print 2005.

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

Author information

1
Department of Neurology, The Medical School, University of Newcastle upon Tyne, Framlington Place, Newcastle upon Tyne, NE2 4HH, UK.

Abstract

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.

PMID:
15653638
PMCID:
PMC546156
DOI:
10.1093/nar/gki169
[Indexed for MEDLINE]
Free PMC Article

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