Mps1 directs the assembly of Cdc20 inhibitory complexes during interphase and mitosis to control M phase timing and spindle checkpoint signaling.
The spindle assembly checkpoint (SAC) in mammals uses cytosolic and kinetochore-based signaling pathways to inhibit anaphase. In this study, we use chemical genetics to show that the protein kinase Mps1 regulates both aspects of the SAC. Human MPS1-null cells were generated via gene targeting and reconstituted with either the wild-type kinase (Mps1(wt)) or a mutant version (Mps1(as)) sensitized to bulky purine analogues. Mps1 inhibition sharply accelerated anaphase onset, such that cells completed mitosis in 12 min, and prevented Cdc20's association with either Mad2 or BubR1 during interphase, i.e., before the appearance of functional kinetochores. Furthermore, intramitotic Mps1 inhibition evicted Bub1 and all other known SAC transducers from the outer kinetochore, but contrary to a recent study, did not perturb aurora B-dependent phosphorylation. We conclude that Mps1 has two complementary roles in SAC regulation: (1) initial cytoplasmic activation of Cdc20 inhibitors and (2) recruitment of factors that promote sustained anaphase inhibition and chromosome biorientation to unattached kinetochores.
Maciejowski
John
J
Memorial Sloan-Kettering Cancer Center, New York, NY 10065, USA.
George
Kelly A
KA
Terret
Marie-Emilie
ME
Zhang
Chao
C
Shokat
Kevan M
KM
Jallepalli
Prasad V
PV
D000705:Anaphase / Q000502:physiology*; D002135:Calcium-Binding Proteins / Q000235:genetics / Q000378:metabolism; D064199:Cdc20 Proteins; D018797:Cell Cycle Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D002455:Cell Division / Q000502:physiology*; D002461:Cell Line, Transformed; D002877:Chromosomes, Human / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D007399:Interphase / Q000502:physiology*; D018386:Kinetochores / Q000378:metabolism; D064246:Mad2 Proteins; D046912:Multiprotein Complexes / Q000235:genetics / Q000378:metabolism*; D017346:Protein Serine-Threonine Kinases / Q000235:genetics / Q000378:metabolism*; D011505:Protein-Tyrosine Kinases; D012097:Repressor Proteins / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction / Q000502:physiology*
D002135:Calcium-Binding Proteins; D064199:Cdc20 Proteins; D018797:Cell Cycle Proteins; C577697:MAD2L1 protein, human; D064246:Mad2 Proteins; D046912:Multiprotein Complexes; D012097:Repressor Proteins; C577488:CDC20 protein, human; D011505:Protein-Tyrosine Kinases; C584277:BUB1 protein, human; C090464:Bub1 spindle checkpoint protein; D017346:Protein Serine-Threonine Kinases; C075840:TTK protein, human