Related Experiment Video

Updated: Jul 8, 2026

Monitoring eIF4F Assembly by Measuring eIF4E-eIF4G Interaction in Live Cells
08:47

Monitoring eIF4F Assembly by Measuring eIF4E-eIF4G Interaction in Live Cells

Published on: May 1, 2020

Translation initiation factor 4E (eIF4E) is regulated by cell death inhibitor, Diap1

Sun Kyung Lee1, Ji Sun Lee, Ki Soon Shin

  • 1Department of Life and Nanopharmaceutical Sciences, Kyung Hee University, Seoul 130-701, Korea.

Molecules and Cells
|January 10, 2008
PubMed

Insights

Drosophila Inhibitor of Apoptosis Protein 1 (Diap1) directly targets translation initiation factor 4E (eIF4E) for degradation. This finding reveals a novel mechanism regulating eIF4E protein levels and impacting cell growth.

Area of Science:

  • Molecular Biology
  • Cell Biology
  • Biochemistry

Background:

  • Translation initiation factor 4E (eIF4E) is crucial for protein synthesis and its dysregulation is linked to cancer.
  • Existing knowledge on eIF4E regulation includes transcriptional control, phosphorylation, and inhibitor binding, but basal protein level control remains unclear.

Purpose of the Study:

  • To investigate the mechanisms regulating the protein level of translation initiation factor 4E (eIF4E) under basal conditions.
  • To identify novel regulators of eIF4E protein stability and their functional consequences.

Main Methods:

  • Direct binding assays to confirm interaction between Diap1 and eIF4E.
  • Ubiquitination assays to assess Diap1's E3 ligase activity on eIF4E.
  • Proteasome inhibition assays to confirm proteasomal degradation pathway.
  • Western blotting to measure protein levels of eIF4E and Cyclin D1.
  • Cell growth assays to evaluate the impact of Diap1 on eIF4E-mediated growth stimulation.

Main Results:

  • Diap1 directly binds to eIF4E.
  • Diap1 poly-ubiquitinates eIF4E, targeting it for proteasome-dependent degradation.
  • Diap1 expression reduces Cyclin D1 protein levels.
  • Diap1 inhibits growth stimulation caused by eIF4E overexpression.

Conclusions:

  • The level of eIF4E protein is regulated by Diap1 through proteasomal degradation.
  • Inhibitor of Apoptosis Proteins (IAPs), like Diap1, may regulate cap-dependent translation by controlling eIF4E protein levels.
  • This provides a new perspective on the role of IAPs in cellular processes beyond apoptosis.

More Related Videos

Xenopus laevis as a Model to Identify Translation Impairment10:24

Xenopus laevis as a Model to Identify Translation Impairment

Published on: September 27, 2015

Preparation of Cell-lines for Conditional Knockdown of Gene Expression and Measurement of the Knockdown Effects on E4orf4-Induced Cell Death13:54

Preparation of Cell-lines for Conditional Knockdown of Gene Expression and Measurement of the Knockdown Effects on E4orf4-Induced Cell Death

Published on: October 21, 2012

Related Concept Videos

Regulation of the Unfolded Protein Response01:31

Regulation of the Unfolded Protein Response

Inositol-requiring kinase one or IRE1 is the most conserved eukaryotic unfolded protein response (UPR) receptor. It is a type I transmembrane protein kinase receptor with a distinctive site-specific RNase activity. As the binding mechanics of the misfolded proteins with the N-terminal domain of IRE-1 are unclear, three binding models — direct, indirect, and allosteric -- are proposed for receptor activation. Nevertheless, it is known that once a misfolded protein associates with IRE1, it...
The Extrinsic Apoptotic Pathway01:17

The Extrinsic Apoptotic Pathway

The extrinsic apoptotic pathway is initiated when extracellular death-inducing signals, such as specific cytokines, activate the death receptors expressed on the cell surface. The immune cells involved in this pathway are natural killer cells (NK cells) and cytotoxic T-lymphocytes. NK cells are critical in innate immune response, while cytotoxic T-lymphocytes are associated with adaptive immune response. These cells recognize specific receptors expressed on the altered cells and activate...
Improving Translational Accuracy02:07

Improving Translational Accuracy

Base complementarity between the three base pairs of mRNA codon and the tRNA anticodon is not a failsafe mechanism. Inaccuracies can range from a single mismatch to no correct base pairing at all. The free energy difference between the correct and nearly correct base pairs can be as small as 3 kcal/ mol. With complementarity being the only proofreading step, the estimated error frequency would be one wrong amino acid in every 100 amino acids incorporated. However, error frequencies observed in...
Initiation of Translation02:33

Initiation of Translation

Initiating translation is complex because it involves multiple molecules. Initiator tRNA, ribosomal subunits, and eukaryotic initiation factors (eIFs) are all required to assemble on the initiation codon of mRNA. This process consists of several steps that are mediated by different eIFs.
First, the initiator tRNA must be selected from the pool of elongator tRNAs by eukaryotic initiation factor 2 (eIF2). The initiator tRNA (Met-tRNAi) has conserved sequence elements including modified bases at...
Eukaryotic Transcription Inhibitors01:52

Eukaryotic Transcription Inhibitors

Certain biochemical processes, such as embryonic development and cell growth regulation, depend on the repression of specific genes. DNA binding proteins known as eukaryotic transcription inhibitors regulate the repression of gene expression in eukaryotes. The presence of these inhibitors at the required location and time in the cell is triggered by the presence of hormones and additional signals from other cells.
Eukaryotic transcription inhibitors usually contain two distinct domains, a DNA...
Transcription Elongation Factors02:35

Transcription Elongation Factors

Transcription elongation is a dynamic process that alters depending upon the sequence heterogeneity of the DNA being transcribed. Hence, it is not surprising that the elongation complex's composition also varies along the way while transcribing a gene.
The transcription elongation is regulated via pausing of RNA polymerase on several occasions during transcription. In bacteria, these halts are necessary because the transcription of DNA into mRNA is coupled to the translation of that mRNA into a...