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Updated: Jun 2, 2026
08:47
Monitoring eIF4F Assembly by Measuring eIF4E-eIF4G Interaction in Live Cells
Published on: May 1, 2020
Human eIF4AIII interacts with an eIF4G-like partner, NOM1, revealing an evolutionarily conserved function outside the
Andrei Alexandrov1, David Colognori, Joan A Steitz
1Department of Molecular Biophysics and Biochemistry, Howard Hughes Medical Institute, Yale University School of Medicine, New Haven, Connecticut 06536, USA.
Genes & Development
|May 18, 2011
Summary
Yeast Fal1p is functionally similar to human eIF4AIII, interacting with Sgd1p. This conserved complex, including human NOM1 and eIF4AIII, plays a role in pre-rRNA processing.
Area of Science:
- Molecular Biology
- RNA Processing
- Protein Interactions
Background:
- Saccharomyces cerevisiae possesses Fal1p, a DEAD-box helicase homologous to human eIF4AIII, despite lacking the exon junction complex (EJC).
- The function of Fal1p and its interacting partners in yeast and human systems remains incompletely understood.
Purpose of the Study:
- To investigate the functional orthology between yeast Fal1p and human eIF4AIII.
- To identify and characterize interacting partners of Fal1p and eIF4AIII.
- To elucidate the role of the conserved Fal1p/Sgd1p and eIF4AIII/NOM1 complex in cellular processes.
Main Methods:
- Complementation assays using human eIF4AIII in fal1Δ yeast.
- Genetic interaction studies between fal1 and sgd1 mutations.
- X-ray crystallography-based structural comparisons.
- In vitro and in vivo co-immunoprecipitation assays.
- RNA interference (RNAi)-mediated knockdown in human cells.
Main Results:
- Human eIF4AIII complements lethal and rRNA biogenesis defects in fal1Δ yeast, confirming functional orthology.
- Yeast Fal1p genetically interacts with Sgd1p, an eIF4G-like protein.
- Direct physical interactions were demonstrated between yeast Sgd1p and Fal1p, and their human orthologs, eIF4AIII and NOM1.
- Human NOM1 is identified as a novel interacting partner of eIF4AIII.
- Knockdown of eIF4AIII and NOM1 in human cells reveals their involvement in pre-rRNA processing.
Conclusions:
- Yeast Fal1p and human eIF4AIII are functional orthologs.
- A conserved complex involving eIF4A-like helicases (Fal1p/eIF4AIII) and eIF4G-like proteins (Sgd1p/NOM1) exists in yeast and humans.
- This complex plays a crucial role in pre-rRNA processing, extending the known functions of these proteins beyond translation initiation and EJC formation.
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