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Loss of the Greatwall Kinase Weakens the Spindle Assembly Checkpoint

Diril, M. Kasim ; Bisteau, Xavier ; Kitagawa, Mayumi ; Caldez, Matias J. ; Wee, Sheena ; Gunaratne, Jayantha ; Lee, Sang Hyun and Kaldis, Philipp LU (2016) In PLoS Genetics 12(9). p.1-26
Abstract

The Greatwall kinase/Mastl is an essential gene that indirectly inhibits the phosphatase activity toward mitotic Cdk1 substrates. Here we show that although Mastl knockout (MastlNULL) MEFs enter mitosis, they progress through mitosis without completing cytokinesis despite the presence of misaligned chromosomes, which causes chromosome segregation defects. Furthermore, we uncover the requirement of Mastl for robust spindle assembly checkpoint (SAC) maintenance since the duration of mitotic arrest caused by microtubule poisons in MastlNULL MEFs is shortened, which correlates with premature disappearance of the essential SAC protein Mad1 at the kinetochores. Notably, MastlNULL MEFs display reduced... (More)

The Greatwall kinase/Mastl is an essential gene that indirectly inhibits the phosphatase activity toward mitotic Cdk1 substrates. Here we show that although Mastl knockout (MastlNULL) MEFs enter mitosis, they progress through mitosis without completing cytokinesis despite the presence of misaligned chromosomes, which causes chromosome segregation defects. Furthermore, we uncover the requirement of Mastl for robust spindle assembly checkpoint (SAC) maintenance since the duration of mitotic arrest caused by microtubule poisons in MastlNULL MEFs is shortened, which correlates with premature disappearance of the essential SAC protein Mad1 at the kinetochores. Notably, MastlNULL MEFs display reduced phosphorylation of a number of proteins in mitosis, which include the essential SAC kinase MPS1. We further demonstrate that Mastl is required for multi-site phosphorylation of MPS1 as well as robust MPS1 kinase activity in mitosis. In contrast, treatment of MastlNULL cells with the phosphatase inhibitor okadaic acid (OKA) rescues the defects in MPS1 kinase activity, mislocalization of phospho-MPS1 as well as Mad1 at the kinetochore, and premature SAC silencing. Moreover, using in vitro dephosphorylation assays, we demonstrate that Mastl promotes persistent MPS1 phosphorylation by inhibiting PP2A/B55-mediated MPS1 dephosphorylation rather than affecting Cdk1 kinase activity. Our findings establish a key regulatory function of the Greatwall kinase/Mastl->PP2A/B55 pathway in preventing premature SAC silencing.

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author
publishing date
type
Contribution to journal
publication status
published
subject
in
PLoS Genetics
volume
12
issue
9
article number
e1006310
pages
1 - 26
publisher
Public Library of Science
external identifiers
  • scopus:84990196016
  • pmid:27631493
ISSN
1553-7390
DOI
10.1371/journal.pgen.1006310
language
English
LU publication?
no
id
a87c147b-4084-4432-887d-eae767f4f413
date added to LUP
2019-09-18 13:46:50
date last changed
2019-11-27 03:23:20
@article{a87c147b-4084-4432-887d-eae767f4f413,
  abstract     = {<p>The Greatwall kinase/Mastl is an essential gene that indirectly inhibits the phosphatase activity toward mitotic Cdk1 substrates. Here we show that although Mastl knockout (Mastl<sup>NULL</sup>) MEFs enter mitosis, they progress through mitosis without completing cytokinesis despite the presence of misaligned chromosomes, which causes chromosome segregation defects. Furthermore, we uncover the requirement of Mastl for robust spindle assembly checkpoint (SAC) maintenance since the duration of mitotic arrest caused by microtubule poisons in Mastl<sup>NULL</sup> MEFs is shortened, which correlates with premature disappearance of the essential SAC protein Mad1 at the kinetochores. Notably, Mastl<sup>NULL</sup> MEFs display reduced phosphorylation of a number of proteins in mitosis, which include the essential SAC kinase MPS1. We further demonstrate that Mastl is required for multi-site phosphorylation of MPS1 as well as robust MPS1 kinase activity in mitosis. In contrast, treatment of Mastl<sup>NULL</sup> cells with the phosphatase inhibitor okadaic acid (OKA) rescues the defects in MPS1 kinase activity, mislocalization of phospho-MPS1 as well as Mad1 at the kinetochore, and premature SAC silencing. Moreover, using in vitro dephosphorylation assays, we demonstrate that Mastl promotes persistent MPS1 phosphorylation by inhibiting PP2A/B55-mediated MPS1 dephosphorylation rather than affecting Cdk1 kinase activity. Our findings establish a key regulatory function of the Greatwall kinase/Mastl-&gt;PP2A/B55 pathway in preventing premature SAC silencing.</p>},
  author       = {Diril, M. Kasim and Bisteau, Xavier and Kitagawa, Mayumi and Caldez, Matias J. and Wee, Sheena and Gunaratne, Jayantha and Lee, Sang Hyun and Kaldis, Philipp},
  issn         = {1553-7390},
  language     = {eng},
  month        = {09},
  number       = {9},
  pages        = {1--26},
  publisher    = {Public Library of Science},
  series       = {PLoS Genetics},
  title        = {Loss of the Greatwall Kinase Weakens the Spindle Assembly Checkpoint},
  url          = {http://dx.doi.org/10.1371/journal.pgen.1006310},
  doi          = {10.1371/journal.pgen.1006310},
  volume       = {12},
  year         = {2016},
}