Drosophila Polo regulates the spindle assembly checkpoint through Mps1-dependent BubR1 phosphorylation

Conde, Carlos; Osswald, Mariana; Barbosa, João; Moutinho‐Santos, Tatiana; Pinheiro, Diana; Guimarães, Sofia; Matos, Irina; Maiato, Hélder; Sunkel, Cláudio E.

doi:10.1038/emboj.2013.109

Cited by 47 publications

(81 citation statements)

References 77 publications

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“…Long‐lasting Polo activation or permanent Spindly Ser499 phosphorylation stalls KTs in labile interactions with MTs. Our data confirm a destabilizing role for Polo in KT‐MT attachments which has also been shown to operate through the control the kinase exerts over the recruitment and activation of Aurora B and the MT depolymerizing motor Kif2b (Hood et al , ; Conde et al , ; Carmena et al , ). Hence, high levels of active Polo in early mitosis ensure efficient correction of merotelic and syntelic attachments, errors that typically occur upon nuclear envelope breakdown as a result of stochastic interactions between KTs and spindle MTs (Paul et al , ; Zaytsev & Grishchuk, ).…”

Section: Discussionsupporting

confidence: 83%

Polo regulates Spindly to prevent premature stabilization of kinetochore–microtubule attachments

et al. 2019

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Accurate chromosome segregation in mitosis requires sister kinetochores to bind to microtubules from opposite spindle poles. The stability of kinetochore-microtubule attachments is fine-tuned to prevent or correct erroneous attachments while preserving amphitelic interactions. Polo kinase has been implicated in both stabilizing and destabilizing kinetochore-microtubule attachments. However, the mechanism underlying Polo-destabilizing activity remains elusive. Here, resorting to an RNAi screen in Drosophila for suppressors of a constitutively active Polo mutant, we identified a strong genetic interaction between Polo and the Rod-ZW10-Zwilch (RZZ) complex, whose kinetochore accumulation has been shown to antagonize microtubule stability. We find that Polo phosphorylates Spindly and impairs its ability to bind to Zwilch. This precludes dynein-mediated removal of the RZZ from kinetochores and consequently delays the formation of stable end-on attachments. We propose that high Polo-kinase activity following mitotic entry directs the RZZ complex to minimize premature stabilization of erroneous attachments, whereas a decrease in active Polo in later mitotic stages allows the formation of stable amphitelic spindle attachments. Our findings demonstrate that Polo tightly regulates the RZZ-Spindly-dynein module during mitosis to ensure the fidelity of chromosome segregation.

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Section: Discussionsupporting

confidence: 83%

Polo regulates Spindly to prevent premature stabilization of kinetochore–microtubule attachments

et al. 2019

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“…Since Drosophila Spc105/KNL1 inherently lacks phospho-regulatable MELTs (Schittenhelm et al, 2009; Conde et al, 2013) but PP1 is still required for timely mitotic exit in flies (Chen et al, 2007), we resorted to this model organism to uncover novel SAC-silencing mechanisms that might have been overlooked in other systems.…”

Section: Resultsmentioning

confidence: 99%

“…Immunostaining was performed as described previously (Conde et al, 2013). Images were collected in Leica TCS SP5 II laser scanning confocal microscope (Leica Microsystems, Germany).…”

Section: Methodsmentioning

confidence: 99%

Protein Phosphatase 1 inactivates Mps1 to ensure efficient Spindle Assembly Checkpoint silencing

Moura

Osswald

Leça

et al. 2017

eLife

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Faithfull genome partitioning during cell division relies on the Spindle Assembly Checkpoint (SAC), a conserved signaling pathway that delays anaphase onset until all chromosomes are attached to spindle microtubules. Mps1 kinase is an upstream SAC regulator that promotes the assembly of an anaphase inhibitor through a sequential multi-target phosphorylation cascade. Thus, the SAC is highly responsive to Mps1, whose activity peaks in early mitosis as a result of its T-loop autophosphorylation. However, the mechanism controlling Mps1 inactivation once kinetochores attach to microtubules and the SAC is satisfied remains unknown. Here we show in vitro and in Drosophila that Protein Phosphatase 1 (PP1) inactivates Mps1 by dephosphorylating its T-loop. PP1-mediated dephosphorylation of Mps1 occurs at kinetochores and in the cytosol, and inactivation of both pools of Mps1 during metaphase is essential to ensure prompt and efficient SAC silencing. Overall, our findings uncover a mechanism of SAC inactivation required for timely mitotic exit.DOI: http://dx.doi.org/10.7554/eLife.25366.001

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“…Full-length BubR1 has been shown (13) to sustain more robust mitotic checkpoint signaling than the kinetochore localization-competent variant BubR1 N , which contains the Bub3 and N-terminal Cdc20 binding sites but is missing the internal Cdc20 binding site and the kinase domain. Although the role of the BubR1 kinase domain remains controversial [with evidence that kinase activity is stimulated by binding to CENP-E (45) and conflicting with evidence that it is an inactive pseudokinase (46)], BubR1 has been recently proposed to be required for Cdc20 recruitment to the Drosophila melanogaster kinetochore (47,48). These findings led us to test whether BubR1 localization to the kinetochore enhances recruitment of Cdc20 to kinetochores in human cells.…”

Section: Bub3-mediated Kinetochore Recruitment Of Bubr1 Enhances Mitoticmentioning

confidence: 99%

Bimodal activation of BubR1 by Bub3 sustains mitotic checkpoint signaling

Han¹,

Vitre²,

Fachinetti³

et al. 2014

Proc. Natl. Acad. Sci. U.S.A.

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Significance The mitotic checkpoint (or the spindle assembly checkpoint) ensures genome integrity by preventing premature chromosome segregation. The pathway is triggered locally by kinetochores, multiprotein complexes assembled onto centromeres. Unattached kinetochores produce Mad2 bound to Cdc20, the mitotic activator of the E3 ubiquitin ligase APC/C. The initial Mad2–Cdc20 complex is then converted into the final mitotic checkpoint inhibitor Bub3–BubR1–Cdc20 that blocks APC/C (anaphase promoting complex or cyclosome)-dependent ubiquitination of cyclin B and securin, thereby stabilizing them and preventing an advance to anaphase. In this study, we identify dual mechanisms by which Bub3 promotes mitotic checkpoint signaling. Bub3 binding to BubR1 promotes two distinct BubR1–Cdc20 interactions, one acting at unattached kinetochores and the other cytoplasmically to facilitate production of the mitotic checkpoint inhibitor.

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Drosophila Polo regulates the spindle assembly checkpoint through Mps1-dependent BubR1 phosphorylation

Cited by 47 publications

References 77 publications

Polo regulates Spindly to prevent premature stabilization of kinetochore–microtubule attachments

Polo regulates Spindly to prevent premature stabilization of kinetochore–microtubule attachments

Protein Phosphatase 1 inactivates Mps1 to ensure efficient Spindle Assembly Checkpoint silencing

Bimodal activation of BubR1 by Bub3 sustains mitotic checkpoint signaling

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