Phenotypic diversity and temporal variability in a bacterial signaling network revealed by single-cell FRET

  1. Johannes M Keegstra
  2. Keita Kamino
  3. François Anquez
  4. Milena D Lazova
  5. Thierry Emonet
  6. Thomas S Shimizu  Is a corresponding author
  1. AMOLF Institute, Netherlands
  2. Yale University, United States

Abstract

We present in vivo single-cell FRET measurements in the Escherichia coli chemotaxis system that reveal pervasive signaling variability, both across cells in isogenic populations and within individual cells over time. We quantify cell-to-cell variability of adaptation, ligand response, as well as steady-state output level, and analyze the role of network design in shaping this diversity from gene expression noise. In the absence of changes in gene expression, we find that single cells demonstrate strong temporal fluctuations. We provide evidence that such signaling noise can arise from at least two sources: (i) stochastic activities of adaptation enzymes, and (ii) receptor-kinase dynamics in the absence of adaptation. We demonstrate that under certain conditions, (ii) can generate giant fluctuations that drive signaling activity of the entire cell into a stochastic two-state switching regime. Our findings underscore the importance of molecular noise, arising not only in gene expression but also in protein networks.

Article and author information

Author details

  1. Johannes M Keegstra

    AMOLF Institute, Amsterdam, Netherlands
    Competing interests
    The authors declare that no competing interests exist.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0002-8877-4881
  2. Keita Kamino

    AMOLF Institute, Amsterdam, Netherlands
    Competing interests
    The authors declare that no competing interests exist.
  3. François Anquez

    AMOLF Institute, Amsterdam, Netherlands
    Competing interests
    The authors declare that no competing interests exist.
  4. Milena D Lazova

    AMOLF Institute, Amsterdam, Netherlands
    Competing interests
    The authors declare that no competing interests exist.
  5. Thierry Emonet

    Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, United States
    Competing interests
    The authors declare that no competing interests exist.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0002-6746-6564
  6. Thomas S Shimizu

    AMOLF Institute, Amsterdam, Netherlands
    For correspondence
    shimizu@amolf.nl
    Competing interests
    The authors declare that no competing interests exist.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0003-0040-7380

Funding

Nederlandse Organisatie voor Wetenschappelijk Onderzoek (NWO Vidi 680-47-515)

  • Thomas S Shimizu

Stichting voor Fundamenteel Onderzoek der Materie (FOM Projectruimte 11PR2958)

  • Thomas S Shimizu

Paul G. Allen Family Foundation (11562)

  • Thierry Emonet
  • Thomas S Shimizu

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

Reviewing Editor

  1. Naama Barkai, Weizmann Institute of Science, Israel

Version history

  1. Received: April 4, 2017
  2. Accepted: November 17, 2017
  3. Accepted Manuscript published: December 12, 2017 (version 1)
  4. Accepted Manuscript updated: December 14, 2017 (version 2)
  5. Version of Record published: February 12, 2018 (version 3)

Copyright

© 2017, Keegstra 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

  • 3,713
    views
  • 622
    downloads
  • 48
    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. Johannes M Keegstra
  2. Keita Kamino
  3. François Anquez
  4. Milena D Lazova
  5. Thierry Emonet
  6. Thomas S Shimizu
(2017)
Phenotypic diversity and temporal variability in a bacterial signaling network revealed by single-cell FRET
eLife 6:e27455.
https://doi.org/10.7554/eLife.27455

Share this article

https://doi.org/10.7554/eLife.27455

Further reading

    1. Computational and Systems Biology
    2. Genetics and Genomics
    Weichen Song, Yongyong Shi, Guan ning Lin
    Tools and Resources

    We propose a new framework for human genetic association studies: at each locus, a deep learning model (in this study, Sei) is used to calculate the functional genomic activity score for two haplotypes per individual. This score, defined as the Haplotype Function Score (HFS), replaces the original genotype in association studies. Applying the HFS framework to 14 complex traits in the UK Biobank, we identified 3619 independent HFS–trait associations with a significance of p < 5 × 10−8. Fine-mapping revealed 2699 causal associations, corresponding to a median increase of 63 causal findings per trait compared with single-nucleotide polymorphism (SNP)-based analysis. HFS-based enrichment analysis uncovered 727 pathway–trait associations and 153 tissue–trait associations with strong biological interpretability, including ‘circadian pathway-chronotype’ and ‘arachidonic acid-intelligence’. Lastly, we applied least absolute shrinkage and selection operator (LASSO) regression to integrate HFS prediction score with SNP-based polygenic risk scores, which showed an improvement of 16.1–39.8% in cross-ancestry polygenic prediction. We concluded that HFS is a promising strategy for understanding the genetic basis of human complex traits.

    1. Computational and Systems Biology
    Qianmu Yuan, Chong Tian, Yuedong Yang
    Tools and Resources

    Revealing protein binding sites with other molecules, such as nucleic acids, peptides, or small ligands, sheds light on disease mechanism elucidation and novel drug design. With the explosive growth of proteins in sequence databases, how to accurately and efficiently identify these binding sites from sequences becomes essential. However, current methods mostly rely on expensive multiple sequence alignments or experimental protein structures, limiting their genome-scale applications. Besides, these methods haven’t fully explored the geometry of the protein structures. Here, we propose GPSite, a multi-task network for simultaneously predicting binding residues of DNA, RNA, peptide, protein, ATP, HEM, and metal ions on proteins. GPSite was trained on informative sequence embeddings and predicted structures from protein language models, while comprehensively extracting residual and relational geometric contexts in an end-to-end manner. Experiments demonstrate that GPSite substantially surpasses state-of-the-art sequence-based and structure-based approaches on various benchmark datasets, even when the structures are not well-predicted. The low computational cost of GPSite enables rapid genome-scale binding residue annotations for over 568,000 sequences, providing opportunities to unveil unexplored associations of binding sites with molecular functions, biological processes, and genetic variants. The GPSite webserver and annotation database can be freely accessed at https://bio-web1.nscc-gz.cn/app/GPSite.