PT  - JOURNAL ARTICLE
AU  - Babhrubahan Roy
AU  - Vikash Verma
AU  - Janice Sim
AU  - Adrienne Fontan
AU  - Ajit P. Joglekar
TI  - Minimization of a harmful cross-talk between mitotic checkpoint silencing and error correction
AID  - 10.1101/459594
DP  - 2019 Jan 01
TA  - bioRxiv
PG  - 459594
4099  - http://biorxiv.org/content/early/2019/06/10/459594.short
4100  - http://biorxiv.org/content/early/2019/06/10/459594.full
AB  - Accurate chromosome segregation during cell division requires that the pair of sister kinetochores on each chromosome attach to microtubules originating from opposite spindle poles. This is ensured by the combined action of the Spindle Assembly Checkpoint (SAC), which detects unattached kinetochores, and an error correction mechanism that destabilizes incorrect attachment of both sister kinetochores to the same spindle pole. These processes are downregulated by Protein Phosphatase 1 (PP1), which both silences the SAC and stabilizes kinetochore-microtubule attachments. We find that this dual PP1 role can be problematic: if PP1 is recruited to the kinetochore for SAC silencing prior to chromosome biorientation, it interferes with error correction. We show that to mitigate this cross-talk, the yeast kinetochore uses independent PP1 sources to stabilize correct attachments and to silence the SAC, and also delays the recruitment of PP1 for SAC silencing. Consequently, chromosome biorientation precedes SAC silencing ensuring accurate chromosome segregation.