Toxoplasma gondii F-actin forms an extensive filamentous network required for material exchange and parasite maturation

  1. Javier Periz
  2. Jamie Whitelaw
  3. Clare Harding
  4. Simon Gras
  5. Mario Igor Del Rosario Minina
  6. Fernanda Latorre-Barragan
  7. Leandro Lemgruber
  8. Madita Alice Reimer
  9. Robert Insall
  10. Aoife Heaslip  Is a corresponding author
  11. Markus Meissner  Is a corresponding author
  1. University of Glasgow, United Kingdom
  2. Cancer Research UK Beatson Institute, United Kingdom
  3. University of Vermont, United States

Abstract

Apicomplexan actin is important during the parasite's life cycle. Its polymerization kinetics are unusual, permitting only short, unstable F-actin filaments. It has not been possible to study actin in vivo and so its physiological roles have remained obscure, leading to models distinct from conventional actin behaviour. Here a modified version of the commercially available Actin-Chromobody® was tested as a novel tool for visualising F-actin dynamics in Toxoplasma gondii. Cb labels filamentous actin structures within the parasite cytosol and labels an extensive F-actin network that connects parasites within the parasitophorous vacuole and allows vesicles to be exchanged between parasites. In the absence of actin, parasites lack a residual body and inter-parasite connections and grow in an asynchronous and disorganized manner. Collectively, these data identify new roles for actin in the intracellular phase of the parasites lytic cycle and provide a robust new tool for imaging parasitic F-actin dynamics.

Article and author information

Author details

  1. Javier Periz

    Division of Infection and Immunity, Institute of Biomedical Life Sciences, University of Glasgow, Glasgow, United Kingdom
    Competing interests
    The authors declare that no competing interests exist.
  2. Jamie Whitelaw

    Division of Infection and Immunity, Institute of Biomedical Life Sciences, University of Glasgow, Glasgow, United Kingdom
    Competing interests
    The authors declare that no competing interests exist.
  3. Clare Harding

    Division of Infection and Immunity, Institute of Biomedical Life Sciences, University of Glasgow, Glasgow, United Kingdom
    Competing interests
    The authors declare that no competing interests exist.
  4. Simon Gras

    Division of Infection and Immunity, Institute of Biomedical Life Sciences, University of Glasgow, Glasgow, United Kingdom
    Competing interests
    The authors declare that no competing interests exist.
  5. Mario Igor Del Rosario Minina

    Division of Infection and Immunity, Institute of Biomedical Life Sciences, University of Glasgow, Glasgow, United Kingdom
    Competing interests
    The authors declare that no competing interests exist.
  6. Fernanda Latorre-Barragan

    Division of Infection and Immunity, Institute of Biomedical Life Sciences, University of Glasgow, Glasgow, United Kingdom
    Competing interests
    The authors declare that no competing interests exist.
  7. Leandro Lemgruber

    Division of Infection and Immunity, Institute of Biomedical Life Sciences, University of Glasgow, Glasgow, United Kingdom
    Competing interests
    The authors declare that no competing interests exist.
  8. Madita Alice Reimer

    Division of Infection and Immunity, Institute of Biomedical Life Sciences, University of Glasgow, Glasgow, United Kingdom
    Competing interests
    The authors declare that no competing interests exist.
  9. Robert Insall

    Cancer Research UK Beatson Institute, Bearsden, United Kingdom
    Competing interests
    The authors declare that no competing interests exist.
  10. Aoife Heaslip

    Department of Molecular Physiology and Biophysics Burlington, University of Vermont, Vermont, United States
    For correspondence
    aoife.heaslip@uconn.edu
    Competing interests
    The authors declare that no competing interests exist.
  11. Markus Meissner

    Division of Infection and Immunity, Institute of Biomedical Life Sciences, University of Glasgow, Glasgow, United Kingdom
    For correspondence
    markus.meissner@glasgow.ac.uk
    Competing interests
    The authors declare that no competing interests exist.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0002-4816-5221

Funding

Wellcome (087582/Z/08/Z)

  • Markus Meissner

H2020 European Research Council (ERC-2012-StG 309255-EndoTox)

  • Markus Meissner

Wellcome (WT103972AIA)

  • Clare Harding

National Institute for Health Research (AI121885)

  • Aoife Heaslip

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

Reviewing Editor

  1. Anna Akhmanova, Utrecht University, Netherlands

Publication history

  1. Received: December 12, 2016
  2. Accepted: March 9, 2017
  3. Accepted Manuscript published: March 21, 2017 (version 1)
  4. Version of Record published: March 31, 2017 (version 2)

Copyright

© 2017, Periz 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.

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  1. Javier Periz
  2. Jamie Whitelaw
  3. Clare Harding
  4. Simon Gras
  5. Mario Igor Del Rosario Minina
  6. Fernanda Latorre-Barragan
  7. Leandro Lemgruber
  8. Madita Alice Reimer
  9. Robert Insall
  10. Aoife Heaslip
  11. Markus Meissner
(2017)
Toxoplasma gondii F-actin forms an extensive filamentous network required for material exchange and parasite maturation
eLife 6:e24119.
https://doi.org/10.7554/eLife.24119

Further reading

  1. A parasite called Toxoplasma gondii builds a scaffold inside human and other animal cells to help it multiply and cause disease.

    1. Cell Biology
    2. Physics of Living Systems
    Robert Kiewisz et al.
    Research Article Updated

    During cell division, kinetochore microtubules (KMTs) provide a physical linkage between the chromosomes and the rest of the spindle. KMTs in mammalian cells are organized into bundles, so-called kinetochore-fibers (k-fibers), but the ultrastructure of these fibers is currently not well characterized. Here, we show by large-scale electron tomography that each k-fiber in HeLa cells in metaphase is composed of approximately nine KMTs, only half of which reach the spindle pole. Our comprehensive reconstructions allowed us to analyze the three-dimensional (3D) morphology of k-fibers and their surrounding MTs in detail. We found that k-fibers exhibit remarkable variation in circumference and KMT density along their length, with the pole-proximal side showing a broadening. Extending our structural analysis then to other MTs in the spindle, we further observed that the association of KMTs with non-KMTs predominantly occurs in the spindle pole regions. Our 3D reconstructions have implications for KMT growth and k-fiber self-organization models as covered in a parallel publication applying complementary live-cell imaging in combination with biophysical modeling (Conway et al., 2022). Finally, we also introduce a new visualization tool allowing an interactive display of our 3D spindle data that will serve as a resource for further structural studies on mitosis in human cells.