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p31(comet) acts to ensure timely spindle checkpoint silencing subsequent to kinetochore attachment

Hagan, Robert S
Manak, Michael S
Buch, Håkon Kirkeby
Meier, Michelle G
Shah, Jagesh V
Sorger, Peter K
Published in Molecular Biology of the Cell. 2011, vol. 22, no. 22, p. 4236-46
Abstract The spindle assembly checkpoint links the onset of anaphase to completion of chromosome-microtubule attachment and is mediated by the binding of Mad and Bub proteins to kinetochores of unattached or maloriented chromosomes. Mad2 and BubR1 traffic between kinetochores and the cytosol, thereby transmitting a "wait anaphase" signal to the anaphase-promoting complex. It is generally assumed that this signal dissipates automatically upon kinetochore-microtubule binding, but it has been shown that under conditions of nocodazole-induced arrest p31(comet), a Mad2-binding protein, is required for mitotic progression. In this article we investigate the localization and function of p31(comet) during normal, unperturbed mitosis in human and marsupial cells. We find that, like Mad2, p31(comet) traffics on and off kinetochores and is also present in the cytosol. Cells depleted of p31(comet) arrest in metaphase with mature bipolar kinetochore-microtubule attachments, a satisfied checkpoint, and high cyclin B levels. Thus p31(comet) is required for timely mitotic exit. We propose that p31(comet) is an essential component of the machinery that silences the checkpoint during each cell cycle.
Keywords Adaptor Proteins, Signal Transducing/metabolismAnimalsCalcium-Binding Proteins/metabolismCell Cycle/drug effectsCell Cycle Proteins/metabolismCell LineChromosomes, Human/metabolismChromosomes, Mammalian/metabolismCyclin B/analysisCytosolHumansKinetochores/metabolismM Phase Cell Cycle CheckpointsMicrotubules/metabolismMitosis/drug effectsMitotic Spindle Apparatus/metabolismNocodazole/pharmacologyNuclear Proteins/metabolismPotoroidaeProtein TransportProtein-Serine-Threonine Kinases/metabolismRNA InterferenceRepressor Proteins/metabolismSignal TransductionTubulin Modulators/pharmacology
PMID: 21965286
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HAGAN, Robert S et al. p31(comet) acts to ensure timely spindle checkpoint silencing subsequent to kinetochore attachment. In: Molecular Biology of the Cell, 2011, vol. 22, n° 22, p. 4236-46.

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Deposited on : 2013-01-22

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