Protein phosphatase 1 inactivates Mps1 to ensure efficient spindle assembly checkpoint silencing
Abstract
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.
Article and author information
Author details
Funding
FEDER-Fundo Europeu de Desenvolvimento Regional funds through the COMPETE 2020 (Norte-01-0145-FEDER-000029)
- Margarida Moura
- Claudio E Sunkel
- Carlos Conde
Fundação para a Ciência e a Tecnologia (PTDC7BEX-BCM/1921/2014-PR041602)
- Claudio E Sunkel
Fundação para a Ciência e a Tecnologia (PEst-C/SAU/LA0002/2013-Incentivo2014-BGCT)
- Claudio E Sunkel
Fundação para a Ciência e a Tecnologia (FCT Investigator grant IF/01755/2014)
- Carlos Conde
Fundação para a Ciência e a Tecnologia (GABBA PhD Program grant PD/BD/105746/2014)
- Mariana Osswald
Fundação para a Ciência e a Tecnologia (FCT PhD grant SFRH/BD/87871/2012)
- João Barbosa
European Research Council (PRECISE)
- Helder Maiato
European Research Council (CODECHECK)
- Helder Maiato
FLAD Life Science
- Helder Maiato
The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.
Reviewing Editor
- Andrea Musacchio, Max Planck Institute of Molecular Physiology, Germany
Version history
- Received: January 23, 2017
- Accepted: April 29, 2017
- Accepted Manuscript published: May 2, 2017 (version 1)
- Accepted Manuscript updated: May 4, 2017 (version 2)
- Version of Record published: May 16, 2017 (version 3)
Copyright
© 2017, Moura et al.
This article is distributed under the terms of the Creative Commons Attribution License permitting unrestricted use and redistribution provided that the original author and source are credited.
Metrics
-
- 9,967
- views
-
- 711
- downloads
-
- 45
- citations
Views, downloads and citations are aggregated across all versions of this paper published by eLife.
Download links
Downloads (link to download the article as PDF)
Open citations (links to open the citations from this article in various online reference manager services)
Cite this article (links to download the citations from this article in formats compatible with various reference manager tools)
Further reading
-
- Cell Biology
Retinal pigment epithelium (RPE) cells show heterogeneous levels of pigmentation when cultured in vitro. To know whether their color in appearance is correlated with the function of the RPE, we analyzed the color intensities of human-induced pluripotent stem cell-derived RPE cells (iPSC-RPE) together with the gene expression profile at the single-cell level. For this purpose, we utilized our recent invention, Automated Live imaging and cell Picking System (ALPS), which enabled photographing each cell before RNA-sequencing analysis to profile the gene expression of each cell. While our iPSC-RPE were categorized into four clusters by gene expression, the color intensity of iPSC-RPE did not project any specific gene expression profiles. We reasoned this by less correlation between the actual color and the gene expressions that directly define the level of pigmentation, from which we hypothesized the color of RPE cells may be a temporal condition not strongly indicating the functional characteristics of the RPE.
-
- Cancer Biology
- Cell Biology
Pancreatic ductal adenocarcinoma carries a dismal prognosis, with high rates of metastasis and few treatment options. Hyperactivation of KRAS in almost all tumours drives RAC1 activation, conferring enhanced migratory and proliferative capacity as well as macropinocytosis. Macropinocytosis is well understood as a nutrient scavenging mechanism, but little is known about its functions in trafficking of signaling receptors. We find that CYRI-B is highly expressed in pancreatic tumours in a mouse model of KRAS and p53-driven pancreatic cancer. Deletion of Cyrib (the gene encoding CYRI-B protein) accelerates tumourigenesis, leading to enhanced ERK and JNK-induced proliferation in precancerous lesions, indicating a potential role as a buffer of RAC1 hyperactivation in early stages. However, as disease progresses, loss of CYRI-B inhibits metastasis. CYRI-B depleted tumour cells show reduced chemotactic responses to lysophosphatidic acid, a major driver of tumour spread, due to impaired macropinocytic uptake of the lysophosphatidic acid receptor-1. Overall, we implicate CYRI-B as a mediator of growth and signaling in pancreatic cancer, providing new insights into pathways controlling metastasis.