PP1 initiates the dephosphorylation of MASTL, triggering mitotic exit and bistability in human cells.
J Cell Sci
; 129(7): 1340-54, 2016 Apr 01.
Article
em En
| MEDLINE
| ID: mdl-26872783
ABSTRACT
Entry into mitosis is driven by the phosphorylation of thousands of substrates, under the master control of Cdk1. During entry into mitosis, Cdk1, in collaboration with MASTL kinase, represses the activity of the major mitotic protein phosphatases, PP1 and PP2A, thereby ensuring mitotic substrates remain phosphorylated. For cells to complete and exit mitosis, these phosphorylation events must be removed, and hence, phosphatase activity must be reactivated. This reactivation of phosphatase activity presumably requires the inhibition of MASTL; however, it is not currently understood what deactivates MASTL and how this is achieved. In this study, we identified that PP1 is associated with, and capable of partially dephosphorylating and deactivating, MASTL during mitotic exit. Using mathematical modelling, we were able to confirm that deactivation of MASTL is essential for mitotic exit. Furthermore, small decreases in Cdk1 activity during metaphase are sufficient to initiate the reactivation of PP1, which in turn partially deactivates MASTL to release inhibition of PP2A and, hence, create a feedback loop. This feedback loop drives complete deactivation of MASTL, ensuring a strong switch-like activation of phosphatase activity during mitotic exit.
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Texto completo:
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Base de dados:
MEDLINE
Assunto principal:
Proteínas Serina-Treonina Quinases
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Quinases Ciclina-Dependentes
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Proteína Fosfatase 1
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Proteína Fosfatase 2
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Proteínas Associadas aos Microtúbulos
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Mitose
Limite:
Humans
Idioma:
En
Revista:
J Cell Sci
Ano de publicação:
2016
Tipo de documento:
Article
País de afiliação:
Austrália