Bub3p Facilitates Spindle Checkpoint Silencing in Fission Yeast.
Hardwick lab paper featured in Molecular Biology of the Cell.
Authors
Vanoosthuyse V, Meadows JC, van d Sar SJ, Millar JB, Hardwick KG.
Mol Biol Cell. 2009 Oct 21. [Epub ahead of print]
Summary
Although critical for spindle checkpoint signalling, the role kinetochores play in APC inhibition remains unclear. Here we show that spindle checkpoint proteins are severely depleted from unattached kinetochores in fission yeast cells lacking Bub3p. Surprisingly, a robust mitotic arrest is maintained in the vast majority of bub3D cells, yet they die, suggesting that Bub3p is essential for successful checkpoint recovery. During recovery, two defects are observed: 1) cells mis-segregate chromosomes and 2) anaphase onset is significantly delayed. We show that Bub3p is required to activate the APC upon inhibition of Aurora kinase activity in checkpoint-arrested cells, suggesting that Bub3p is required for efficient checkpoint silencing downstream of Aurora kinase. Together, these results suggest that spindle checkpoint signals can be amplified in the nucleoplasm, yet kinetochore localisation of spindle checkpoint components is required for proper recovery from a spindle checkpoint-dependent arrest.
Copyright © 2009 by The American Society for Cell Biology