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

Moura, Margarida; Osswald, Mariana; Leça, Nelson; Barbosa, João; Pereira, António J.; Maiato, Hélder; Sunkel, Cláudio E.; Conde, Carlos

doi:10.7554/elife.25366

Cited by 49 publications

(59 citation statements)

References 79 publications

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“…In flies, the KNL1-MELTs are not phosphoregulated and MPS1/PLK1 activities are not required to recruit the BUB complex to kinetochores 44,45 . However, in this situation, PP1 binds directly to MPS1 to inhibit its activity and silence the downstream SAC signal 46 . Therefore, the use of regulated phosphatases to silence local kinase activity may be a conserved feature of SAC signalling.…”

Section: Discussionmentioning

confidence: 99%

Kinetochore phosphatases suppress autonomous kinase activity to control the spindle assembly checkpoint

Smith

Saurin

2019

Preprint

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Local phosphatase regulation is critical for determining when phosphorylation signals are activated or deactivated. A typical example is the spindle assembly checkpoint (SAC) during mitosis, which regulates kinetochore PP1 and PP2A-B56 activities to switch-off signalling events at the correct time. In this case, kinetochore phosphatase activation dephosphorylates MELT motifs on KNL1 to remove SAC proteins, including the BUB complex. We show here that, surprisingly, neither PP1 or PP2A are required to dephosphorylate the MELT motifs. Instead, they remove polo-like kinase 1 (PLK1) from the BUB complex, which can otherwise maintain MELT phosphorylation in an autocatalytic manner. This is their principle role in the SAC, because both phosphatases become redundant if PLK1 is inhibited or BUB-PLK1 interaction is prevented. Therefore, phosphatase regulation is critical for the SAC, but primarily to restrain and extinguish autonomous kinase activity. We propose that these circuits have evolved to generate a semi-autonomous SAC signal that can be synchronously silenced following kinetochore-microtubule tension.

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Section: Discussionmentioning

confidence: 99%

Kinetochore phosphatases suppress autonomous kinase activity to control the spindle assembly checkpoint

Smith

Saurin

2019

Preprint

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“…Unlike in mammals, Drosophila homozygous mutants for mad2 SAC gene (mad2 ∆ ) are viable and fertile [26]. Our laboratory characterized another SAC mutant (ald G4422 ) which encodes the mps1 gene [27][28], that allows survival of a small percentage of homozygous flies until adult stages.…”

Section: Drosophila Intestinal Stem Cells Are Sac Competentmentioning

confidence: 99%

Aneuploidy promotes intestinal dysplasia in Drosophila

Resende

Monteiro

Brás

et al. 2018

Preprint

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Aneuploidy is associated with different human diseases, particularly cancer, but how different cell types within tissues respond to aneuploidy is not fully understood. In some studies, aneuploidy has been shown to have a deleterious effect and lead to cell death, however it has also been shown to be a causal event of tumorigenesis in other contexts.Here, we show that Drosophila intestinal stem cells have a particular tolerance to aneuploidy and do not activate apoptosis in response to chromosome misegregation like other non-stem cells. Instead, we observe the development of tissue dysplasia characterized by an accumulation of progenitor cells, increased stem cell proliferation rate, and an excess of cells of the enteroendocrine lineage. Our findings highlight the importance of mechanisms acting to prevent aneuploidy within tissue stem cells and provide an in vivo model of how these cells can act as reservoirs for genomic alterations that can lead to dysplasia.

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“…Both PP2A-B56 and PP1 have been implicated in KNL1 dephosphorylation and SAC silencing (Espert et al, 2014;Nijenhuis et al, 2014). PP1 has been shown to dephosphorylate the MPS1 T-loop in flies (Moura et al, 2017), but it is not clear whether this mechanism is conserved in mammals. PP2A-B56 exists in several spatially distinct populations in mammalian mitotic cells (Qian et al, 2013;Vallardi et al, 2019).…”

Section: Introductionmentioning

confidence: 99%

Checkpoint signaling and error correction require regulation of the MPS1 T-loop by PP2A-B56

Hayward

Bancroft

Mangat

et al. 2019

Journal of Cell Biology

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Supplemental Figure legendsFigure S1. MPS1 autophosphorylation and localisation are regulated by PP2A-B56. (A) Control depleted or MPS1-depleted HeLa MPS1-GFP mitotic cells were treated with MPS1 inhibitor or DMSO for 5 min as indicated. Cells were stained with antibodies against MPS1 pT676 and CENP-C. Total MPS1-GFP was detected by GFP fluorescence. (B) Recombinant, insect cell expressed wild type (WT) or kinasedead (KD) His-MPS1 was treated with l-phosphatase or reaction buffer alone and analysed by SDS-PAGE and Coomassie Brilliant Blue staining (CBB) or Western blotting with antibodies against MPS1 pT676. (C) MPS1 T-loop phosphorylation and endogenous MPS1 levels were assessed in control depleted mitotic HeLa MPS1-GFP cells or HeLa MPS1-GFP cells depleted of PP1αβγ (siPP1), PP2CA (siPP2A), PPP4C (siPP4), PPP5C (siPP5) or PPP6C (siPP6) and treated with MPS1i as indicated. Mean kinetochore MPS1 pT676 phosphorylation (D) and MPS1-GFP kinetochore levels ± SEM (E) relative to CENP-C are plotted. Values are from three independent experiments with 15 kinetochores measured in at least 10 cells per condition. (F) Representative Western blot analysis of PP1, PP2A, PP4, PP5 and PP6 depletion efficiencies. Actin is shown as a loading control. (G) Representative Western blot of PP2A-B55 and PP2A-B56 depletion efficiencies. Actin is used as a loading control. (H) Western blot of HeLa-Flp-In/TREx GFP-BUBR1 WT or GFP-

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

Cited by 49 publications

References 79 publications

Kinetochore phosphatases suppress autonomous kinase activity to control the spindle assembly checkpoint

Kinetochore phosphatases suppress autonomous kinase activity to control the spindle assembly checkpoint

Aneuploidy promotes intestinal dysplasia in Drosophila

Checkpoint signaling and error correction require regulation of the MPS1 T-loop by PP2A-B56

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