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

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

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.

"This ORCID iD identifies the author of this article:" 0000-0003-4009-5940
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.
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.
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.
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.
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.

"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

Jennifer G. DeLuca, Colorado State University, United States

Publication history

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

Copyright

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.