mRNA-programmed translation pauses in the targeting of E. coli membrane proteins

  1. Nir Fluman
  2. Sivan Navon
  3. Eitan Bibi
  4. Yitzhak Pilpel  Is a corresponding author
  1. Weizmann Institute of Science, Israel

Abstract

In all living organisms, ribosomes translating membrane proteins are targeted to membrane translocons early in translation, by the ubiquitous Signal Recognition Particle (SRP) system. In eukaryotes, the SRP Alu domain arrests translation elongation of membrane proteins until targeting is complete. Curiously however, the Alu domain is lacking in most eubacteria. Here, by analyzing genome-wide data on translation rates, we identified a potential compensatory mechanism in E. coli that serves to slow down translation during membrane protein targeting. The underlying mechanism is likely programmed into the coding sequence, where Shine-Dalgarno-like elements trigger elongation pauses at strategic positions during early stages of translation. We provide experimental evidence that slow translation during targeting improves membrane protein production fidelity, as it correlates with better folding of overexpressed membrane proteins. Thus, slow elongation is important for membrane protein targeting in E. coli, which utilizes mechanisms different from the eukaryotic one to control translation speed.

Article and author information

Author details

  1. Nir Fluman

    Weizmann Institute of Science, Rehovot, Israel
    Competing interests
    The authors declare that no competing interests exist.
  2. Sivan Navon

    Weizmann Institute of Science, Rehovot, Israel
    Competing interests
    The authors declare that no competing interests exist.
  3. Eitan Bibi

    Weizmann Institute of Science, Rehovot, Israel
    Competing interests
    The authors declare that no competing interests exist.
  4. Yitzhak Pilpel

    Weizmann Institute of Science, Rehovot, Israel
    For correspondence
    Pilpel@weizmann.ac.il
    Competing interests
    The authors declare that no competing interests exist.

Reviewing Editor

  1. Nahum Sonenberg, McGill University, Canada

Version history

  1. Received: May 21, 2014
  2. Accepted: August 16, 2014
  3. Accepted Manuscript published: August 18, 2014 (version 1)
  4. Version of Record published: September 23, 2014 (version 2)

Copyright

© 2014, Fluman 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

  • 4,593
    views
  • 442
    downloads
  • 65
    citations

Views, downloads and citations are aggregated across all versions of this paper published by eLife.

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)

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

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

  1. Nir Fluman
  2. Sivan Navon
  3. Eitan Bibi
  4. Yitzhak Pilpel
(2014)
mRNA-programmed translation pauses in the targeting of E. coli membrane proteins
eLife 3:e03440.
https://doi.org/10.7554/eLife.03440

Share this article

https://doi.org/10.7554/eLife.03440

Further reading

    1. Cell Biology
    Yuki Date, Yukiko Sasazawa ... Shinji Saiki
    Research Article

    The autophagy-lysosome pathway plays an indispensable role in the protein quality control by degrading abnormal organelles and proteins including a-synuclein (aSyn) associated with the pathogenesis of Parkinson's disease (PD). However, the activation of this pathway is mainly by targeting lysosomal enzymic activity. Here, we focused on the autophagosome-lysosome fusion process around the microtubule-organizing center (MTOC) regulated by lysosomal positioning. Through high-throughput chemical screening, we identified 6 out of 1,200 clinically approved drugs enabling the lysosomes to accumulate around the MTOC with autophagy flux enhancement. We further demonstrated that these compounds induce the lysosomal clustering through a JIP4-TRPML1-dependent mechanism. Among them, the lysosomal-clustering compound albendazole promoted the autophagy-dependent degradation of Triton-X-insoluble, proteasome inhibitor-induced aggregates. In a cellular PD model, albendazole boosted insoluble aSyn degradation. Our results revealed that lysosomal clustering can facilitate the breakdown of protein aggregates, suggesting that lysosome-clustering compounds may offer a promising therapeutic strategy against neurodegenerative diseases characterized by the presence of aggregate-prone proteins.

    1. Cell Biology
    Yuhao Wang, Linhao Ruan ... Rong Li
    Research Article

    Mitochondria are the cellular energy hub and central target of metabolic regulation. Mitochondria also facilitate proteostasis through pathways such as the ‘mitochondria as guardian in cytosol’ (MAGIC) whereby cytosolic misfolded proteins (MPs) are imported into and degraded inside mitochondria. In this study, a genome-wide screen in Saccharomyces cerevisiae uncovered that Snf1, the yeast AMP-activated protein kinase (AMPK), inhibits the import of MPs into mitochondria while promoting mitochondrial biogenesis under glucose starvation. We show that this inhibition requires a downstream transcription factor regulating mitochondrial gene expression and is likely to be conferred through substrate competition and mitochondrial import channel selectivity. We further show that Snf1/AMPK activation protects mitochondrial fitness in yeast and human cells under stress induced by MPs such as those associated with neurodegenerative diseases.