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Updated: Jul 6, 2026
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Monitoring eIF4F Assembly by Measuring eIF4E-eIF4G Interaction in Live Cells
Published on: May 1, 2020
The eIF4E RNA regulon promotes the Akt signaling pathway
Biljana Culjkovic1, Keith Tan, Slobodanka Orolicki
1Institute for Research in Immunology and Cancer, Université de Montréal, Montréal, Québec H4M 1J6, Canada.
The Journal of Cell Biology
|April 9, 2008
Summary
Eukaryotic initiation factor 4E (eIF4E) promotes cell survival by activating Akt signaling. This protein enhances cellular proliferation and rescues cells from apoptosis, partly through up-regulating NBS1 expression.
Area of Science:
- Cell Biology
- Molecular Biology
- Cancer Research
Background:
- Eukaryotic initiation factor 4E (eIF4E) is crucial for cellular proliferation and survival.
- The precise mechanisms by which eIF4E confers resistance to apoptosis, particularly during serum starvation, remain incompletely understood.
- Akt signaling is a key pathway involved in cell survival and proliferation.
Purpose of the Study:
- To elucidate the molecular mechanisms by which eIF4E promotes survival and rescues cells from apoptosis.
- To investigate the role of the Akt pathway in eIF4E-mediated apoptotic rescue.
- To identify upstream regulators and downstream effectors involved in this process.
Main Methods:
- Overexpression of wild-type and mutant eIF4E in fibroblasts.
- Assessment of cell survival and apoptosis under serum-deprived conditions.
- Analysis of Akt pathway activation, including Akt1 and upstream activators like NBS1.
- Evaluation of mRNA export and translation efficiency.
- Investigation of the role of promyelocytic leukemia protein (PML) as a negative regulator.
Main Results:
- eIF4E overexpression enhances survival signaling through Akt activation, requiring Akt1 for apoptotic rescue.
- A translation-defective but mRNA export-competent eIF4E mutant effectively rescues cells, indicating a role beyond translation initiation.
- eIF4E up-regulates Nijmegen breakage syndrome 1 (NBS1), an upstream activator of the phosphoinositide-3 kinase-Akt pathway.
- eIF4E also up-regulates downstream effectors of the Akt pathway, amplifying its pro-survival signals.
- Promyelocytic leukemia protein (PML) inhibits eIF4E-mediated Akt activation and apoptotic rescue, partly by blocking NBS1 mRNA export.
Conclusions:
- eIF4E promotes cell survival and rescues cells from apoptosis by coordinately regulating gene expression to potentiate Akt activation.
- NBS1 up-regulation and subsequent Akt pathway activation are critical components of eIF4E's pro-survival function.
- PML acts as a negative regulator, suppressing eIF4E's ability to activate Akt and rescue cells from apoptosis.
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