The eukaryotic translation initiation factor eIF4E is responsible for the recognition of the mRNA cap structure and, as such, plays a key role in the selection of mRNAs for translation. The interaction of eIF4E with the 'multi-adaptor' eIF4G (and thus recruitment of ribosomes to mRNA) can be regulated via competitive binding of 4E-binding proteins (4E-BPs). 4E-BPs have broad functions in cell growth, proliferation and development. We have found that disruption of the genes for either of the yeast 4E-BPs (Eap1p or Caf20p) leads to an inhibition of pseudohyphal growth in the resulting diploid yeast strain following nitrogen limitation. Specific 4E-binding domain mutations destroy the capacity of each 4E-BP gene to complement the non-pseudohyphal phenotype, suggesting that a translational function for the 4E-BPs is important for pseudohyphal growth. In addition, neither of the 4E-BP deletion strains is deficient in global or stress-regulated protein synthesis. However, our evidence reveals that the two 4E-BPs are functionally distinct with regard to pseudohyphal growth. Therefore, this work supports a model where the yeast 4E-BPs are acting on specific mRNAs to facilitate a defined proliferative response to environmental stress in yeast.

• PMID: 17083129
• DOI full text
• PubMed

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Journal Article | Research Support, Non-U.S. Gov't

Authors

Ibrahimo S, Holmes LE, Ashe MP

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