1. Cell Biology

Ordered dephosphorylation initiated by the selective proteolysis of cyclin B drives mitotic exit

  1. James Holder  Is a corresponding author
  2. Shabaz Mohammed
  3. Francis A Barr  Is a corresponding author
  1. University of Oxford, United Kingdom
https://doi.org/10.7554/eLife.59885
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  1. James Holder
  2. Shabaz Mohammed
  3. Francis A Barr
(2020)
Ordered dephosphorylation initiated by the selective proteolysis of cyclin B drives mitotic exit
eLife 9:e59885.
https://doi.org/10.7554/eLife.59885
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Abstract

APC/C-mediated proteolysis of cyclin B and securin promotes anaphase entry, inactivating CDK1 and permitting chromosome segregation, respectively. Reduction of CDK1 activity relieves inhibition of the CDK1-counteracting phosphatases PP1 and PP2A-B55, allowing wide-spread dephosphorylation of substrates. Meanwhile, continued APC/C activity promotes proteolysis of other mitotic regulators. Together, these activities orchestrate a complex series of events during mitotic exit. However, the relative importance of regulated proteolysis and dephosphorylation in dictating the order and timing of these events remains unclear. Using high temporal-resolution proteomics, we compare the relative extent of proteolysis and protein dephosphorylation. This reveals highly-selective rapid proteolysis of cyclin B, securin and geminin at the metaphase-anaphase transition, followed by slow proteolysis of other substrates. Dephosphorylation requires APC/C-dependent destruction of cyclin B and was resolved into PP1-dependent categories with unique sequence motifs. We conclude that dephosphorylation initiated by selective proteolysis of cyclin B drives the bulk of changes observed during mitotic exit.

Data availability

Source data files have been provided for Figures 2, 3, 6 and 7. These include a processed form of the raw data, where some extraneous metadata has been removed.Full raw data is available at PRIDE with the following accession numbers: FIgure 2 Total Proteome PXD019791, Figure 2 Phospho-proteome PXD019788, Figure 3 PXD019795, Figure 6 PXD019787, Figure 7 PXD019786

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The following previously published data sets were used

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Author details

  1. James Holder

    Sir William Dunn School of Pathology, University of Oxford, Oxford, United Kingdom
    For correspondence
    james.holder@path.ox.ac.uk
    Competing interests
    The authors declare that no competing interests exist.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0001-7597-3104

  2. Shabaz Mohammed

    Biochemistry Department, University of Oxford, Oxford, United Kingdom
    Competing interests
    The authors declare that no competing interests exist.

  3. Francis A Barr

    Department of Biochemistry, University of Oxford, Oxford, United Kingdom
    For correspondence
    francis.barr@bioch.ox.ac.uk
    Competing interests
    The authors declare that no competing interests exist.

Funding

Cancer Research UK (Program Grant)

  • James Holder
  • Francis A Barr

Wellcome (PhD Award)

  • James Holder

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

Copyright

© 2020, Holder 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. James Holder
  2. Shabaz Mohammed
  3. Francis A Barr
(2020)
Ordered dephosphorylation initiated by the selective proteolysis of cyclin B drives mitotic exit
eLife 9:e59885.
https://doi.org/10.7554/eLife.59885

Share this article

https://doi.org/10.7554/eLife.59885

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