NCBI Summary:
This gene encodes a dual specificity protein kinase with the ability to phosphorylate tyrosine, serine and threonine. Associated with cell proliferation, this protein is essential for chromosome alignment at the centromere during mitosis and is required for centrosome duplication. It has been found to be a critical mitotic checkpoint protein for accurate segregation of chromosomes during mitosis. Tumorigenesis may occur when this protein fails to degrade and produces excess centrosomes resulting in aberrant mitotic spindles. Alternative splicing results in multiple transcript variants. [provided by RefSeq, Nov 2009]
Mps1 kinase-dependent Sgo2 centromere localisation mediates cohesin protection in mouse oocyte meiosis I. El Yakoubi W et al. (2017) A key feature of meiosis is the step-wise removal of cohesin, the protein complex holding sister chromatids together, first from arms in meiosis I and then from the centromere region in meiosis II. Centromeric cohesin is protected by Sgo2 from Separase-mediated cleavage, in order to maintain sister chromatids together until their separation in meiosis II. Failures in step-wise cohesin removal result in aneuploid gametes, preventing the generation of healthy embryos. Here, we report that kinase activities of Bub1 and Mps1 are required for Sgo2 localisation to the centromere region. Mps1 inhibitor-treated oocytes are defective in centromeric cohesin protection, whereas oocytes devoid of Bub1 kinase activity, which cannot phosphorylate H2A at T121, are not perturbed in cohesin protection as long as Mps1 is functional. Mps1 and Bub1 kinase activities localise Sgo2 in meiosis I preferentially to the centromere and pericentromere respectively, indicating that Sgo2 at the centromere is required for protection.In meiosis I centromeric cohesin is protected by Sgo2 from Separase-mediated cleavage ensuring that sister chromatids are kept together until their separation in meiosis II. Here the authors demonstrate that Bub1 and Mps1 kinase activities are required for Sgo2 localisation to the centromere region.//////////////////
DNA damage induces a kinetochore-based ATM/ATR-independent SAC arrest unique to the first meiotic division in mouse oocytes.
Lane SIR et al. (2017) Mouse oocytes carrying DNA damage arrest in meiosis I, thereby preventing creation of embryos with deleterious mutations. The arrest is dependent on the spindle assembly checkpoint, which results in anaphase-promoting complex (APC) inhibition. However, little is understood about how this checkpoint is engaged following DNA damage. Here, we find that within minutes DNA damage assembles checkpoint proteins at the kinetochore, not at damage sites along chromosome arms, such that the APC is fully inhibited within 30 min. Despite this robust response, there is no measurable loss in k-fibres, or tension across the bivalent. Through pharmacological inhibition we observed the response is dependent on Mps1 kinase, Aurora kinase, and haspin. Using oocyte specific knockouts we find the response does not require the DNA damage response kinases ATM or ATR. Furthermore, checkpoint activation does not occur in response to DNA damage in fully mature eggs during meiosis II, despite the divisions being separated by just a few hours. Therefore, mouse oocytes have a unique ability to sense DNA damage rapidly by activating the checkpoint at their kinetochores.//////////////////
Non-canonical function of spindle assembly checkpoint proteins after APC activation reduces aneuploidy in mouse oocytes. Lane SI 2014 et al.
The spindle assembly checkpoint (SAC) prevents aneuploidy by coupling anaphase onset, through anaphase-promoting complex (APC) activation, with chromosome attachment to spindle microtubules. Here, we examine APC activity in oocytes, noted for their susceptibility to chromosome mis-segregation during the first meiotic division (MI). We find that MI oocytes only contain sub-maximal APC activity, measured through cyclin B1-GFP degradation, because inhibition of SAC proteins when the APC is normally fully active increases cyclin B1 degradation twofold and reduces the length of this division by 2?h. In addition, inhibiting the SAC component Mps1 only when the APC is already active increases aneuploidy rates in the resulting egg by up to 30%. We therefore establish that the activities of SAC proteins and the APC co-exist in oocytes, and such concurrence has a vital role in reducing aneuploidy rates by extending MI, probably by allowing time for numerous erroneous microtubule attachments to be corrected.
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Expression regulated by
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Ovarian localization
Oocyte
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Follicle stages
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Phenotypes
Mutations
1 mutations
Species: mouse
Mutation name: None
type: null mutation fertility: infertile - ovarian defect Comment: Mps1 at kinetochores is essential for female mouse meiosis I. Hached K et al. In female meiosis, chromosome missegregations lead to the generation of aneuploid oocytes and can cause the development of trisomies or infertility. Because mammalian female meiosis I is error prone, the full functionality of control mechanisms, such as the spindle assembly checkpoint (SAC), has been put into question. The SAC monitors the correct orientation, microtubule occupancy and tension on proteinaceous structures named kinetochores. Although it has been shown previously that the SAC exists in meiosis I, where attachments are monopolar, the role of microtubule occupancy for silencing the SAC and the importance of certain essential SAC components, such as the kinase Mps1, are unknown in mammalian oocytes. Using a conditional loss-of-function approach, we address the role of Mps1 in meiotic progression and checkpoint control in meiosis I. Our data demonstrate that kinetochore localization of Mps1 is required for the proper timing of prometaphase and is essential for SAC control, chromosome alignment and aurora C localization in meiosis I. The absence of Mps1 from kinetochores severely impairs chromosome segregation in oocyte meiosis I and, therefore, fertility in mice. In addition, we settle a long-standing question in showing that kinetochore-microtubule attachments are present in prometaphase I at a time when most of the SAC protein Mad2 disappears from kinetochores.