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eIF5A Functions Globally in Translation Elongation and Termination
Anthony P Schuller1, Colin Chih-Chien Wu1, Thomas E Dever2
1Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
Molecular Cell
|April 11, 2017
Summary
The eukaryotic translation factor eIF5A plays a crucial role in protein synthesis. This study reveals eIF5A is essential for both translation elongation and termination, impacting protein production globally.
Area of Science:
- Molecular Biology
- Protein Synthesis
- Gene Expression Regulation
Background:
- The eukaryotic translation factor eIF5A was initially identified as an initiation factor.
- Previous research indicated eIF5A's role in promoting translation elongation, particularly for proline-rich sequences.
Purpose of the Study:
- To investigate the broader role of eIF5A in translation elongation.
- To uncover a potential function of eIF5A in translation termination.
- To elucidate the mechanism by which eIF5A influences protein synthesis.
Main Methods:
- Ribosome profiling in an eIF5A-depleted strain.
- In vitro biochemical assays using a reconstituted translation system.
Main Results:
- Ribosome profiling revealed global elongation defects and ribosome stalling at various sequences, not just proline repeats, upon eIF5A depletion.
- Accumulation of ribosomes at stop codons and in the 3' UTR indicated a defect in translation termination.
- In vitro experiments demonstrated eIF5A's promotion of translation of stalling sequences and a significant increase (over 17-fold) in peptidyl-tRNA hydrolysis rate.
Conclusions:
- Eukaryotic translation factor eIF5A has a broad function in both translation elongation and termination.
- These findings explain the high cellular abundance and essential nature of eIF5A for protein synthesis.
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