The spindle checkpoint maintains genomic stability by ensuring that mitosis cannot proceed until all chromosomes are correctly aligned on the spindle. Several kinases, including Bub1, BubR1 and aurora B, are implicated in spindle checkpoint function but exactly how anaphase onset is regulated remains unclear. On p. 3639, Stephen Taylor and co-workers reveal new details of the spindle checkpoint in human somatic cells by showing that Bub1 and aurora B cooperate to maintain BubR1-mediated inhibition of the anaphase promoting complex/cyclosome (APC/C), which targets anaphase inhibitors for degradation. The authors use time-lapse microscopy, RNAi-mediated knockdown of Bub1, chemical inhibition of aurora B, and microtubule-disrupting agents to build a new model for the spindle checkpoint. In this, the checkpoint has two arms: the Bub1 arm monitors attachment of microtubules to kinetochores (the proteinaceous structures that link chromosomes to the spindle) whereas the aurora B arm monitors bi-orientation (attachment of kinetochore pairs to spindles from opposite poles). The arms converge on the mitotic checkpoint complex, which includes BubR1, to promote its binding to and inhibition of APC/C, thereby delaying the metaphase-to-anaphase transition until all the chromosomes are correctly aligned on the spindle.
A two-armed spindle checkpoint
A two-armed spindle checkpoint. J Cell Sci 15 August 2005; 118 (16): e1602. doi:
Download citation file:
Advertisement
Cited by
Introducing our new Editors
We welcome three new Editors to Journal of Cell Science - Robert Parton, Richa Rikhy and Simon Cook. You can read more about them in the Editorial from our Editor-in-Chief Michael Way.
2024 Journal Meeting 'Diversity and Evolution in Cell Biology'
Registration is open for our 2024 Journal Meeting Diversity and Evolution in Cell Biology, which aims to bring together evolutionary biologists and cell biologists investigating diverse aspects of cellular physiology. Final registration deadline: 3 May 2024.
Workshop: Physics of the Early Embryonic Cell Divisions
Early-career researchers interested in the roles of nuclear lipids, apply now for one of the ten funded places at this Workshop, which will take place 11-14 November 2024. Application deadline: 17 May.
Reasons to submit to Journal of Cell Science
There are many benefits to publishing in Journal of Cell Science - read more about why you should choose JCS or visit our submission page now.
Propose a new Workshop for 2026
We are now accepting proposals for our 2026 Workshops programme. We aim to be responsive to the community and open to novel initiatives, so if you have a new idea for a biological workshop that you feel would work well, please apply. Applications deadline: 19 July 2024.