1. Biochemistry and Chemical Biology
  2. Chromosomes and Gene Expression
Download icon

Fail-safe control of translation initiation by dissociation of eIF2α phosphorylated ternary complexes

  1. Martin D Jennings
  2. Christopher J Kershaw
  3. Tomas Adomavicius
  4. Graham D Pavitt  Is a corresponding author
  1. The University of Manchester, United Kingdom
Research Article
  • Cited 36
  • Views 2,109
  • Annotations
Cite this article as: eLife 2017;6:e24542 doi: 10.7554/eLife.24542

Abstract

Phosphorylation of eIF2α controls translation initiation by restricting the levels of active eIF2-GTP-Met-tRNAi ternary complexes (TC). This modulates the expression of all eukaryotic mRNAs and contributes to the cellular integrated stress response. Key to controlling the activity of eIF2 are translation factors eIF2B and eIF5, thought to primarily function with eIF2-GDP and TC respectively. Using a steady-state kinetics approach with purified proteins we demonstrate that eIF2B binds to eIF2 with equal affinity irrespective of the presence or absence of competing guanine nucleotides. We show that eIF2B can compete with Met-tRNAi for eIF2-GTP and can destabilize TC. When TC is formed with unphosphorylated eIF2, eIF5 can out-compete eIF2B to stabilize TC-eIF5 complexes. However when TC-eIF5 is formed with phosphorylated eIF2, eIF2B outcompetes eIF5 and destabilizes TC. These data uncover competition between eIF2B and eIF5 for TC and identify that phosphorylated eIF2-GTP translation initiation intermediate complexes can be inhibited by eIF2B.

Article and author information

Author details

  1. Martin D Jennings

    Division of Molecular and Cellular Function, The University of Manchester, Manchester, United Kingdom
    Competing interests
    The authors declare that no competing interests exist.
  2. Christopher J Kershaw

    Division of Molecular and Cellular Function, The University of Manchester, Manchester, United Kingdom
    Competing interests
    The authors declare that no competing interests exist.
  3. Tomas Adomavicius

    Division of Molecular and Cellular Function, The University of Manchester, Manchester, United Kingdom
    Competing interests
    The authors declare that no competing interests exist.
  4. Graham D Pavitt

    Division of Molecular and Cellular Function, The University of Manchester, Manchester, United Kingdom
    For correspondence
    graham.pavitt@manchester.ac.uk
    Competing interests
    The authors declare that no competing interests exist.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0002-8593-2418

Funding

Biotechnology and Biological Sciences Research Council (BB/L020157/1)

  • Graham D Pavitt

Biotechnology and Biological Sciences Research Council (BB/M006565/1)

  • Graham D Pavitt

Biotechnology and Biological Sciences Research Council (BB/L000652/1)

  • Graham D Pavitt

The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.

Reviewing Editor

  1. Nahum Sonenberg, McGill University, Canada

Publication history

  1. Received: December 21, 2016
  2. Accepted: March 16, 2017
  3. Accepted Manuscript published: March 18, 2017 (version 1)
  4. Version of Record published: April 25, 2017 (version 2)

Copyright

© 2017, Jennings et al.

This article is distributed under the terms of the Creative Commons Attribution License permitting unrestricted use and redistribution provided that the original author and source are credited.

Metrics

  • 2,109
    Page views
  • 470
    Downloads
  • 36
    Citations

Article citation count generated by polling the highest count across the following sources: Crossref, Scopus, PubMed Central.

Download links

A two-part list of links to download the article, or parts of the article, in various formats.

Downloads (link to download the article as PDF)

Download citations (links to download the citations from this article in formats compatible with various reference manager tools)

Open citations (links to open the citations from this article in various online reference manager services)

  1. Further reading

Further reading

    1. Biochemistry and Chemical Biology
    2. Cell Biology
    Thomas S McAlear, Susanne Bechstedt
    Research Article Updated

    Cells increase microtubule dynamics to make large rearrangements to their microtubule cytoskeleton during cell division. Changes in microtubule dynamics are essential for the formation and function of the mitotic spindle, and misregulation can lead to aneuploidy and cancer. Using in vitro reconstitution assays we show that the mitotic spindle protein Cytoskeleton-Associated Protein 2 (CKAP2) has a strong effect on nucleation of microtubules by lowering the critical tubulin concentration 100-fold. CKAP2 increases the apparent rate constant ka of microtubule growth by 50-fold and increases microtubule growth rates. In addition, CKAP2 strongly suppresses catastrophes. Our results identify CKAP2 as the most potent microtubule growth factor to date. These finding help explain CKAP2’s role as an important spindle protein, proliferation marker, and oncogene.

    1. Biochemistry and Chemical Biology
    2. Developmental Biology
    Lucas C Pantaleão et al.
    Research Article Updated

    Maternal obesity during pregnancy has immediate and long-term detrimental effects on the offspring heart. In this study, we characterized the cardiac and circulatory lipid profiles in late gestation E18.5 fetuses of diet-induced obese pregnant mice and established the changes in lipid abundance and fetal cardiac transcriptomics. We used untargeted and targeted lipidomics and transcriptomics to define changes in the serum and cardiac lipid composition and fatty acid metabolism in male and female fetuses. From these analyses we observed: (1) maternal obesity affects the maternal and fetal serum lipidome distinctly; (2) female fetal heart lipidomes are more sensitive to maternal obesity than males; (3) changes in lipid supply might contribute to early expression of lipolytic genes in mouse hearts exposed to maternal obesity. These results highlight the existence of sexually dimorphic responses of the fetal heart to the same in utero obesogenic environment and identify lipids species that might mediate programming of cardiovascular health.