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

Lookup NU author(s): Dr Richard Temperley, Professor Robert Lightowlers, Professor Zofia Chrzanowska-Lightowlers



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.

Publication metadata

Author(s): Seal R, Temperley RJ, Wilusz J, Lightowlers RN, Chrzanowska-Lightowlers ZMA

Publication type: Article

Publication status: Published

Journal: Nucleic Acids Research

Year: 2005

Volume: 33

Issue: 1

Pages: 376-387

Date deposited: 24/10/2007

ISSN (print): 0305-1048

ISSN (electronic): 1362-4954

Publisher: Oxford University Press


DOI: 10.1093/nar/gki169


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