1. Structural Biology and Molecular Biophysics
  2. Microbiology and Infectious Disease

Structural basis for the hijacking of endosomal sorting nexin proteins by Chlamydia trachomatis

  1. Blessy Paul
  2. Hyun Sung Kim
  3. Markus C Kerr
  4. Wilhelmina M Huston
  5. Rohan D Teasdale  Is a corresponding author
  6. Brett M Collins  Is a corresponding author
  1. The University of Queensland, Australia
  2. University of Technology Sydney, Australia
https://doi.org/10.7554/eLife.22311
Share this article
Cite this article
  1. Blessy Paul
  2. Hyun Sung Kim
  3. Markus C Kerr
  4. Wilhelmina M Huston
  5. Rohan D Teasdale
  6. Brett M Collins
(2017)
Structural basis for the hijacking of endosomal sorting nexin proteins by Chlamydia trachomatis
eLife 6:e22311.
https://doi.org/10.7554/eLife.22311
  2. Download BibTeX
  3. Download .RIS

Abstract

During infection chlamydial pathogens form an intracellular membrane-bound replicative niche termed the inclusion, which is enriched with bacterial transmembrane proteins called Incs. Incs bind and manipulate host cell proteins to promote inclusion expansion and provide camouflage against innate immune responses. Sorting nexin (SNX) proteins that normally function in endosomal membrane trafficking are a major class of inclusion-associated host proteins, and are recruited by IncE/CT116. Crystal structures of the SNX5 phox-homology (PX) domain in complex with IncE define the precise molecular basis for these interactions. The binding site is unique to SNX5 and related family members SNX6 and SNX32. Intriguingly the site is also conserved in SNX5 homologues throughout evolution, suggesting that IncE captures SNX5-related proteins by mimicking a native host protein interaction. These findings thus provide the first mechanistic insights both into how chlamydial Incs hijack host proteins, and how SNX5-related PX domains function as scaffolds in protein complex assembly.

Data availability

The following data sets were generated
    1. Collins B
    (2016) Structure of the SNX5 PX domain
    Publicly available at the University of Queensland eSpace (UQ: 409277).
    http://espace.library.uq.edu.au/view/UQ:409277

Article and author information

Author details

  1. Blessy Paul

    Institute for Molecular Bioscience, The University of Queensland, Brisbane, Australia
    Competing interests
    The authors declare that no competing interests exist.

  2. Hyun Sung Kim

    Institute for Molecular Bioscience, The University of Queensland, Brisbane, Australia
    Competing interests
    The authors declare that no competing interests exist.

  3. Markus C Kerr

    Institute for Molecular Bioscience, The University of Queensland, Brisbane, Australia
    Competing interests
    The authors declare that no competing interests exist.

  4. Wilhelmina M Huston

    School of Life Sciences, University of Technology Sydney, Sydney, Australia
    Competing interests
    The authors declare that no competing interests exist.

  5. Rohan D Teasdale

    Institute for Molecular Bioscience, The University of Queensland, Brisbane, Australia
    For correspondence
    r.teasdale@imb.uq.edu.au
    Competing interests
    The authors declare that no competing interests exist.

  6. Brett M Collins

    Institute for Molecular Bioscience, The University of Queensland, Brisbane, Australia
    For correspondence
    b.collins@imb.uq.edu.au
    Competing interests
    The authors declare that no competing interests exist.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0002-6070-3774

Funding

National Health and Medical Research Council (APP1058734)

  • Brett M Collins

National Health and Medical Research Council (606788)

  • Rohan D Teasdale

National Health and Medical Research Council (APP1041929)

  • Brett M Collins

National Health and Medical Research Council (APP1061574)

  • Rohan D Teasdale

Australian Research Council (DP0985029)

  • Brett M Collins

Australian Research Council (DP150100364)

  • Brett M Collins

Australian Research Council (DE120102321)

  • Markus C Kerr

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

Copyright

© 2017, Paul 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

  • 2,360
    views
  • 549
    downloads
  • 64
    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. Blessy Paul
  2. Hyun Sung Kim
  3. Markus C Kerr
  4. Wilhelmina M Huston
  5. Rohan D Teasdale
  6. Brett M Collins
(2017)
Structural basis for the hijacking of endosomal sorting nexin proteins by Chlamydia trachomatis
eLife 6:e22311.
https://doi.org/10.7554/eLife.22311

Share this article

https://doi.org/10.7554/eLife.22311

Categories and tags

Research organism

Further reading

    1. Structural Biology and Molecular Biophysics
    2. Microbiology and Infectious Disease

    Chlamydia interfere with an interaction between the mannose-6-phosphate receptor and sorting nexins to counteract host restriction

    Cherilyn A Elwell, Nadine Czudnochowski ... Oren S Rosenberg
    Research Article Updated

    Chlamydia trachomatis is an obligate intracellular pathogen that resides in a membrane-bound compartment, the inclusion. The bacteria secrete a unique class of proteins, Incs, which insert into the inclusion membrane and modulate the host-bacterium interface. We previously reported that IncE binds specifically to the Sorting Nexin 5 Phox domain (SNX5-PX) and disrupts retromer trafficking. Here, we present the crystal structure of the SNX5-PX:IncE complex, showing IncE bound to a unique and highly conserved hydrophobic groove on SNX5. Mutagenesis of the SNX5-PX:IncE binding surface disrupts a previously unsuspected interaction between SNX5 and the cation-independent mannose-6-phosphate receptor (CI-MPR). Addition of IncE peptide inhibits the interaction of CI-MPR with SNX5. Finally, C. trachomatis infection interferes with the SNX5:CI-MPR interaction, suggesting that IncE and CI-MPR are dependent on the same binding surface on SNX5. Our results provide new insights into retromer assembly and underscore the power of using pathogens to discover disease-related cell biology.

    1. Structural Biology and Molecular Biophysics

    ATP-release pannexin channels are gated by lysophospholipids

    Erik Henze, Russell N Burkhardt ... Toshimitsu Kawate
    Research Article

    In addition to its role as cellular energy currency, adenosine triphosphate (ATP) serves as an extracellular messenger that mediates diverse cell-to-cell communication. Compelling evidence supports that ATP is released from cells through pannexins, a family of membrane proteins that form heptameric large-pore channels. However, the activation mechanisms that trigger ATP release by pannexins remain poorly understood. Here, we discover lysophospholipids as endogenous pannexin activators, using activity-guided fractionation of mouse tissue extracts combined with untargeted metabolomics and electrophysiology. We show that lysophospholipids directly and reversibly activate pannexins in the absence of other proteins. Secretomics experiments reveal that lysophospholipid-activated pannexin 1 leads to the release of not only ATP but also other signaling metabolites, such as 5’-methylthioadenosine, which is important for immunomodulation. We also demonstrate that lysophospholipids activate endogenous pannexin 1 in human monocytes, leading to the release of IL-1β through inflammasome activation. Our results provide a connection between lipid metabolism and purinergic signaling, both of which play major roles in immune responses.

    1. Structural Biology and Molecular Biophysics

    Engineering cardiolipin binding to an artificial membrane protein reveals determinants for lipid-mediated stabilization

    Mia L Abramsson, Robin A Corey ... Michael Landreh
    Research Article

    Integral membrane proteins carry out essential functions in the cell, and their activities are often modulated by specific protein-lipid interactions in the membrane. Here, we elucidate the intricate role of cardiolipin (CDL), a regulatory lipid, as a stabilizer of membrane proteins and their complexes. Using the in silico-designed model protein TMHC4_R (ROCKET) as a scaffold, we employ a combination of molecular dynamics simulations and native mass spectrometry to explore the protein features that facilitate preferential lipid interactions and mediate stabilization. We find that the spatial arrangement of positively charged residues as well as local conformational flexibility are factors that distinguish stabilizing from non-stabilizing CDL interactions. However, we also find that even in this controlled, artificial system, a clear-cut distinction between binding and stabilization is difficult to attain, revealing that overlapping lipid contacts can partially compensate for the effects of binding site mutations. Extending our insights to naturally occurring proteins, we identify a stabilizing CDL site within the E. coli rhomboid intramembrane protease GlpG and uncover its regulatory influence on enzyme substrate preference. In this work, we establish a framework for engineering functional lipid interactions, paving the way for the design of proteins with membrane-specific properties or functions.