Kinetochores attached to microtubule-ends are stabilised by Astrin bound PP1 to ensure proper chromosome segregation

  1. Duccio Conti
  2. Parveen Gul
  3. Asifa Islam
  4. José M Martín-Durán
  5. Richard W Pickersgill
  6. Viji M Draviam  Is a corresponding author
  1. Queen Mary University of London, United Kingdom

Abstract

Microtubules segregate chromosomes by attaching to macromolecular kinetochores. Only microtubule-end attached kinetochores can be pulled apart; how these end-on attachments are selectively recognised and stabilised is not known. Using the kinetochore and microtubule-associated protein, Astrin, as a molecular probe, we show that end-on attachments are rapidly stabilised by spatially-restricted delivery of PP1 near the C-terminus of Ndc80, a core kinetochore-microtubule linker. PP1 is delivered by the evolutionarily conserved tail of Astrin and this promotes Astrin's own enrichment creating a highly-responsive positive feedback, independent of biorientation. Abrogating Astrin:PP1-delivery disrupts attachment stability, which is not rescued by inhibiting Aurora-B, an attachment destabiliser, but is reversed by artificially tethering PP1 near the C-terminus of Ndc80. Constitutive Astrin:PP1-delivery disrupts chromosome congression and segregation, revealing a dynamic mechanism for stabilising attachments. Thus, Astrin-PP1 mediates a dynamic 'lock' that selectively and rapidly stabilises end-on attachments, independent of biorientation, and ensures proper chromosome segregation.

Data availability

All data generated or analysed during this study are included in the manuscript and supporting files.

Article and author information

Author details

  1. Duccio Conti

    Department of Biochemistry, School of Biological and Chemical Sciences, Queen Mary University of London, London, United Kingdom
    Competing interests
    The authors declare that no competing interests exist.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0003-4009-5940
  2. Parveen Gul

    Department of Biochemistry, School of Biological and Chemical Sciences, Queen Mary University of London, London, United Kingdom
    Competing interests
    The authors declare that no competing interests exist.
  3. Asifa Islam

    Department of Biochemistry, School of Biological and Chemical Sciences, Queen Mary University of London, London, United Kingdom
    Competing interests
    The authors declare that no competing interests exist.
  4. José M Martín-Durán

    Department of Biochemistry, School of Biological and Chemical Sciences, Queen Mary University of London, London, United Kingdom
    Competing interests
    The authors declare that no competing interests exist.
  5. Richard W Pickersgill

    Department of Biochemistry, School of Biological and Chemical Sciences, Queen Mary University of London, London, United Kingdom
    Competing interests
    The authors declare that no competing interests exist.
  6. Viji M Draviam

    Department of Biochemistry, School of Biological and Chemical Sciences, Queen Mary University of London, London, United Kingdom
    For correspondence
    v.draviam@qmul.ac.uk
    Competing interests
    The authors declare that no competing interests exist.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0001-8295-3689

Funding

Queen Mary University of London (SBC8DRA2)

  • Viji M Draviam

Biotechnology and Biological Sciences Research Council (R01003X/1)

  • Viji M Draviam

Cancer Research UK (C28598/A9787)

  • Viji M Draviam

Medical Research Council (MR/K50127X/1)

  • Duccio Conti

Islamic Development Bank

  • Parveen Gul

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

Reviewing Editor

  1. Jennifer G. DeLuca, Colorado State University, United States

Publication history

  1. Received: June 14, 2019
  2. Accepted: December 1, 2019
  3. Accepted Manuscript published: December 6, 2019 (version 1)
  4. Version of Record published: December 24, 2019 (version 2)

Copyright

© 2019, Conti 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

  • 3,384
    Page views
  • 451
    Downloads
  • 12
    Citations

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

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. Duccio Conti
  2. Parveen Gul
  3. Asifa Islam
  4. José M Martín-Durán
  5. Richard W Pickersgill
  6. Viji M Draviam
(2019)
Kinetochores attached to microtubule-ends are stabilised by Astrin bound PP1 to ensure proper chromosome segregation
eLife 8:e49325.
https://doi.org/10.7554/eLife.49325

Further reading

    1. Cell Biology
    Meng Zhao, Niels Banhos Dannieskiold-Samsøe ... Katrin J Svensson
    Research Article

    The secreted protein Isthmin-1 (Ism1) mitigates diabetes by increasing adipocyte and skeletal muscle glucose uptake by activating the PI3K-Akt pathway. However, while both Ism1 and insulin converge on these common targets, Ism1 has distinct cellular actions suggesting divergence in downstream intracellular signaling pathways. To understand the biological complexity of Ism1 signaling, we performed phosphoproteomic analysis after acute exposure, revealing overlapping and distinct pathways of Ism1 and insulin. We identify a 53 % overlap between Ism1 and insulin signaling and Ism1-mediated phosphoproteome-wide alterations in ~ 450 proteins that are not shared with insulin. Interestingly, we find several unknown phosphorylation sites on proteins related to protein translation, mTOR pathway and, unexpectedly, muscle function in the Ism1 signaling network. Physiologically, Ism1 ablation in mice results in altered proteostasis, including lower muscle protein levels under fed and fasted conditions, reduced amino acid incorporation into proteins, and reduced phosphorylation of the key protein synthesis effectors Akt and downstream mTORC1 targets. As metabolic disorders such as diabetes are associated with accelerated loss of skeletal muscle protein content, these studies define a non-canonical mechanism by which this anti-diabetic circulating protein controls muscle biology.

    1. Cell Biology
    Jia Chen, Daniel St Johnston
    Research Article

    In the adult Drosophila midgut, basal intestinal stem cells give rise to enteroblasts that integrate into the epithelium as they differentiate into enterocytes. Integrating enteroblasts must generate a new apical domain and break through the septate junctions between neighbouring enterocytes, while maintaining barrier function. We observe that enteroblasts form an apical membrane initiation site (AMIS) when they reach the septate junction between the enterocytes. Cadherin clears from the apical surface and an apical space appears between above the enteroblast. New septate junctions then form laterally with the enterocytes and the AMIS develops into an apical domain below the enterocyte septate junction. The enteroblast therefore forms a pre-assembled apical compartment before it has a free apical surface in contact with the gut lumen. Finally, the enterocyte septate junction disassembles and the enteroblast/pre-enterocyte reaches the gut lumen with a fully-formed brush border. The process of enteroblast integration resembles lumen formation in mammalian epithelial cysts, highlighting the similarities between the fly midgut and mammalian epithelia.