TY - JOUR
T1 - Inefficient degradation of cyclin B1 re-activates the spindle checkpoint right after sister chromatid disjunction
AU - Clijsters, Linda
AU - Van Zon, Wouter
AU - Ter Riet, Bas
AU - Voets, Erik
AU - Boekhout, Michiel
AU - Ogink, Janneke
AU - Rumpf-Kienzl, Cornelia
AU - Wolthuis, Rob M.F.
PY - 2014/8/1
Y1 - 2014/8/1
N2 - Sister chromatid separation creates a sudden loss of tension on kinetochores, which could, in principle, re-activate the spindle checkpoint in anaphase. This so-called "anaphase problem" is probably avoided by timely inactivation of cyclin B1-Cdk1, which may prevent the spindle tension sensing Aurora B kinase from destabilizing kinetochore-microtubule interactions as they lose tension in anaphase. However, exactly how spindle checkpoint re-activation is prevented remains unclear. Here, we investigated how different degrees of cyclin B1 stabilization affected the spindle checkpoint in metaphase and anaphase. Cells expressing a strongly stabilized (R42A) mutant of cyclin B1 degraded APC/CCdc20 substrates normally, showing that checkpoint release was not inhibited by high cyclin B1-Cdk1 activity. However, after this initial wave of APC/CCdc20 activity, the spindle checkpoint returned in cells with uncohesed sister chromatids. Expression of a lysine mutant of cyclin B1 that is degraded only slightly inefficiently allowed a normal metaphase-to-anaphase transition. Strikingly, however, the spindle checkpoint returned in cells that had not degraded the cyclin B1 mutant 10-15 min after anaphase onset. When cyclin B1 remained in late anaphase, cytokinesis stalled, and translocation of INCENP from separated sister chromatids to the spindle midzone was blocked. This late anaphase arrest required the activity of Aurora B and Mps1. In conclusion, our results reveal that complete removal of cyclin B1 is essential to prevent the return of the spindle checkpoint following sister chromatid disjunction. Speculatively, increasing activity of APC/C Cdc20 in late anaphase helps to keep cyclin B1 levels low.
AB - Sister chromatid separation creates a sudden loss of tension on kinetochores, which could, in principle, re-activate the spindle checkpoint in anaphase. This so-called "anaphase problem" is probably avoided by timely inactivation of cyclin B1-Cdk1, which may prevent the spindle tension sensing Aurora B kinase from destabilizing kinetochore-microtubule interactions as they lose tension in anaphase. However, exactly how spindle checkpoint re-activation is prevented remains unclear. Here, we investigated how different degrees of cyclin B1 stabilization affected the spindle checkpoint in metaphase and anaphase. Cells expressing a strongly stabilized (R42A) mutant of cyclin B1 degraded APC/CCdc20 substrates normally, showing that checkpoint release was not inhibited by high cyclin B1-Cdk1 activity. However, after this initial wave of APC/CCdc20 activity, the spindle checkpoint returned in cells with uncohesed sister chromatids. Expression of a lysine mutant of cyclin B1 that is degraded only slightly inefficiently allowed a normal metaphase-to-anaphase transition. Strikingly, however, the spindle checkpoint returned in cells that had not degraded the cyclin B1 mutant 10-15 min after anaphase onset. When cyclin B1 remained in late anaphase, cytokinesis stalled, and translocation of INCENP from separated sister chromatids to the spindle midzone was blocked. This late anaphase arrest required the activity of Aurora B and Mps1. In conclusion, our results reveal that complete removal of cyclin B1 is essential to prevent the return of the spindle checkpoint following sister chromatid disjunction. Speculatively, increasing activity of APC/C Cdc20 in late anaphase helps to keep cyclin B1 levels low.
KW - APC/C
KW - Anaphase
KW - Cdc20
KW - Cdk1
KW - Cyclin B1
KW - Metaphase
KW - Spindle checkpoint
UR - http://www.scopus.com/inward/record.url?scp=84905910336&partnerID=8YFLogxK
U2 - https://doi.org/10.4161/cc.29336
DO - https://doi.org/10.4161/cc.29336
M3 - Article
C2 - 25483188
SN - 1538-4101
VL - 13
SP - 2370
EP - 2378
JO - Cell Cycle
JF - Cell Cycle
IS - 15
ER -