1
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Xu Y, Chao A, Rinaldin M, Kickuth A, Brugués J, Di Talia S. The cell cycle oscillator and spindle length set the speed of chromosome separation in Drosophila embryos. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.06.17.598879. [PMID: 38948726 PMCID: PMC11212860 DOI: 10.1101/2024.06.17.598879] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/02/2024]
Abstract
Anaphase is tightly controlled in space and time to ensure proper separation of chromosomes. The mitotic spindle, the self-organized microtubule structure driving chromosome segregation, scales in size with the available cytoplasm. Yet, the relationship between spindle size and chromosome movement remains poorly understood. Here, we address how the movement of chromosomes changes during the cleavage divisions of the Drosophila blastoderm. We show that the speed of chromosome separation gradually decreases during the 4 nuclear divisions of the blastoderm. This reduction in speed is accompanied by a similar reduction in the length of the spindle, thus ensuring that these two quantities are tightly linked. Using a combination of genetic and quantitative imaging approaches, we find that two processes contribute to controlling the speed at which chromosomes move at mitotic exit: the activity of molecular motors important for microtubule depolymerization and the cell cycle oscillator. Specifically, we found that the levels of Klp10A, Klp67A, and Klp59C, three kinesin-like proteins important for microtubule depolymerization, contribute to setting the speed of chromosome separation. This observation is supported by quantification of microtubule dynamics indicating that poleward flux rate scales with the length of the spindle. Perturbations of the cell cycle oscillator using heterozygous mutants of mitotic kinases and phosphatases revealed that the duration of anaphase increases during the blastoderm cycles and is the major regulator of chromosome velocity. Thus, our work suggests a potential link between the biochemical rate of mitotic exit and the forces exerted by the spindle. Collectively, we propose that the cell cycle oscillator and spindle length set the speed of chromosome separation in anaphase.
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Affiliation(s)
- Yitong Xu
- Department of Cell Biology, Duke University Medical Center, Durham NC 27705, USA
| | - Anna Chao
- Department of Cell Biology, Duke University Medical Center, Durham NC 27705, USA
| | - Melissa Rinaldin
- Cluster of Excellence Physics of Life, TU Dresden, Dresden, 01307 Germany
- Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, 01307 Germany
- Center of Systems Biology, Dresden, 01307 Germany
| | - Alison Kickuth
- Cluster of Excellence Physics of Life, TU Dresden, Dresden, 01307 Germany
- Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, 01307 Germany
- Center of Systems Biology, Dresden, 01307 Germany
| | - Jan Brugués
- Cluster of Excellence Physics of Life, TU Dresden, Dresden, 01307 Germany
- Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, 01307 Germany
- Center of Systems Biology, Dresden, 01307 Germany
| | - Stefano Di Talia
- Department of Cell Biology, Duke University Medical Center, Durham NC 27705, USA
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2
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Leça N, Barbosa F, Rodriguez-Calado S, Moura M, Pedroso PD, Pinto I, Verza AE, Bange T, Sunkel CE, Barisic M, Maresca TJ, Conde C. Proximity-based activation of AURORA A by MPS1 potentiates error correction. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.06.11.598300. [PMID: 38948877 PMCID: PMC11213139 DOI: 10.1101/2024.06.11.598300] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/02/2024]
Abstract
Faithfull cell division relies on mitotic chromosomes becoming bioriented with each pair of sister kinetochores bound to microtubules oriented toward opposing spindle poles. Erroneous kinetochore-microtubule attachments often form during early mitosis, but are destabilized through the phosphorylation of outer kinetochore proteins by centromeric AURORA B kinase (ABK) and centrosomal AURORA A kinase (AAK), thus allowing for re-establishment of attachments until biorientation is achieved. MPS1-mediated phosphorylation of NDC80 has also been shown to directly weaken the kinetochore-microtubule interface in yeast. In human cells, MPS1 has been proposed to transiently accumulate at end-on attached kinetochores and phosphorylate SKA3 to promote microtubule release. Whether MPS1 directly targets NDC80 and/or promotes the activity of AURORA kinases in metazoans remains unclear. Here, we report a novel mechanism involving communication between kinetochores and centrosomes, wherein MPS1 acts upstream of AAK to promote error correction. MPS1 on pole-proximal kinetochores phosphorylates the C-lobe of AAK thereby increasing its activation at centrosomes. This proximity-based activation ensures the establishment of a robust AAK activity gradient that locally destabilizes mal-oriented kinetochores near spindle poles. Accordingly, MPS1 depletion from Drosophila cells causes severe chromosome misalignment and erroneous kinetochore-microtubule attachments, which can be rescued by tethering either MPS1 or constitutively active AAK mutants to centrosomes. Proximity-based activation of AAK by MPS1 also occurs in human cells to promote AAK-mediated phosphorylation of the NDC80 N-terminal tail. These findings uncover an MPS1-AAK cross-talk that is required for efficient error correction, showcasing the ability of kinetochores to modulate centrosome outputs to ensure proper chromosome segregation.
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3
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Shinoda N, Horikoshi M, Taira Y, Muramoto M, Hirayama S, Murata S, Miura M. Caspase cleaves Drosophila BubR1 to modulate spindle assembly checkpoint function and lifespan of the organism. FEBS J 2023; 290:4200-4223. [PMID: 37151120 DOI: 10.1111/febs.16811] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2022] [Revised: 03/23/2023] [Accepted: 05/04/2023] [Indexed: 05/09/2023]
Abstract
Caspases cleave over 1500 substrates in the human proteome in both lethal and non-lethal scenarios. However, reports of the physiological consequences of substrate cleavage are limited. Additionally, the manner in which caspase cleaves only a subset of substrates in the non-lethal scenario remains to be elucidated. BubR1, a spindle assembly checkpoint component, is a caspase substrate in humans, the physiological function of which remains unclear. Here, we found that caspases, especially Drice, cleave Drosophila BubR1 between the N-terminal KEN box motif and C-terminal kinase domain. By using proximity labelling, we found that Drice, but not Dcp-1, is in proximity to BubR1, suggesting that protein proximity facilitates substrate preference. The cleaved fragments displayed altered subcellular localization and protein-protein interactions. Flies that harboured cleavage-resistant BubR1 showed longer duration of BubR1 localization to the kinetochore upon colchicine treatment. Furthermore, these flies showed extended lifespan. Thus, we propose that the caspase-mediated cleavage of BubR1 limits spindle assembly checkpoint and organismal lifespan. Our results highlight the importance of the individual analysis of substrates in vivo to determine the biological significance of caspase-dependent non-lethal cellular processes.
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Affiliation(s)
- Natsuki Shinoda
- Department of Genetics, Graduate School of Pharmaceutical Sciences, The University of Tokyo, Bunkyo-ku, Japan
| | - Misuzu Horikoshi
- Department of Genetics, Graduate School of Pharmaceutical Sciences, The University of Tokyo, Bunkyo-ku, Japan
| | - Yusuke Taira
- Department of Genetics, Graduate School of Pharmaceutical Sciences, The University of Tokyo, Bunkyo-ku, Japan
| | - Masaya Muramoto
- Department of Genetics, Graduate School of Pharmaceutical Sciences, The University of Tokyo, Bunkyo-ku, Japan
| | - Shoshiro Hirayama
- Laboratory of Protein Metabolism, Graduate School of Pharmaceutical Sciences, The University of Tokyo, Bunkyo-ku, Japan
| | - Shigeo Murata
- Laboratory of Protein Metabolism, Graduate School of Pharmaceutical Sciences, The University of Tokyo, Bunkyo-ku, Japan
| | - Masayuki Miura
- Department of Genetics, Graduate School of Pharmaceutical Sciences, The University of Tokyo, Bunkyo-ku, Japan
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4
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Zhang Y, Chen R, Gong L, Huang W, Li P, Zhai Z, Ling E. Regulation of intestinal stem cell activity by a mitotic cell cycle regulator Polo in Drosophila. G3 (BETHESDA, MD.) 2023; 13:jkad084. [PMID: 37154439 PMCID: PMC10234410 DOI: 10.1093/g3journal/jkad084] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/05/2023] [Accepted: 03/31/2023] [Indexed: 05/10/2023]
Abstract
Maintaining a definite and stable pool of dividing stem cells plays an important role in organ development. This process requires an appropriate progression of mitosis for proper spindle orientation and polarity to ensure the ability of stem cells to proliferate and differentiate correctly. Polo-like kinases (Plks)/Polo are the highly conserved serine/threonine kinases involved in the initiation of mitosis as well as in the progression of the cell cycle. Although numerous studies have investigated the mitotic defects upon loss of Plks/Polo in cells, little is known about the in vivo consequences of stem cells with abnormal Polo activity in the context of tissue and organism development. The current study aimed to investigate this question using the Drosophila intestine, an organ dynamically maintained by the intestinal stem cells (ISCs). The results indicated that the polo depletion caused a reduction in the gut size due to a gradual decrease in the number of functional ISCs. Interestingly, the polo-deficient ISCs showed an extended G2/M phase and aneuploidy and were subsequently eliminated by premature differentiation into enterocytes (ECs). In contrast, the constitutively active Polo (poloT182D) suppressed ISC proliferation, induced abnormal accumulation of β-tubulin in cells, and drove ISC loss via apoptosis. Therefore, Polo activity should be properly maintained for optimal stem cell function. Further analysis suggested that polo was a direct target gene of Sox21a, a Sox transcription factor that critically regulates stem cell activity. Together, this study provided a novel perspective on the correlation between the progression of mitosis and the ISC function in Drosophila.
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Affiliation(s)
- Ying Zhang
- Research Center for Translational Medicine at Shanghai East Hospital, School of Life Sciences and Technology, Tongji University, Shanghai 200092, China
- CAS Key Laboratory of Insect Developmental and Evolutionary Biology, CAS Center for Excellence in Molecular Plant Sciences, The Chinese Academy of Science, Shanghai 200032, China
- University of Chinese Academy of Sciences, Beijing 101408, China
| | - Rongbing Chen
- CAS Key Laboratory of Insect Developmental and Evolutionary Biology, CAS Center for Excellence in Molecular Plant Sciences, The Chinese Academy of Science, Shanghai 200032, China
- University of Chinese Academy of Sciences, Beijing 101408, China
| | - Liyuan Gong
- CAS Key Laboratory of Insect Developmental and Evolutionary Biology, CAS Center for Excellence in Molecular Plant Sciences, The Chinese Academy of Science, Shanghai 200032, China
- University of Chinese Academy of Sciences, Beijing 101408, China
| | - Wuren Huang
- CAS Key Laboratory of Insect Developmental and Evolutionary Biology, CAS Center for Excellence in Molecular Plant Sciences, The Chinese Academy of Science, Shanghai 200032, China
| | - Ping Li
- Research Center for Translational Medicine at Shanghai East Hospital, School of Life Sciences and Technology, Tongji University, Shanghai 200092, China
| | - Zongzhao Zhai
- Hunan Provincial Key Laboratory of Animal Intestinal Function and Regulation, College of Life Sciences, Hunan Normal University, Changsha 410081, China
| | - Erjun Ling
- CAS Key Laboratory of Insect Developmental and Evolutionary Biology, CAS Center for Excellence in Molecular Plant Sciences, The Chinese Academy of Science, Shanghai 200032, China
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5
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Audett MR, Johnson EL, McGory JM, Barcelos DM, Szalai EO, Przewloka MR, Maresca TJ. The microtubule- and PP1-binding activities of Drosophila melanogaster Spc105 control the kinetics of SAC satisfaction. Mol Biol Cell 2022; 33:ar1. [PMID: 34705493 PMCID: PMC8886820 DOI: 10.1091/mbc.e21-06-0307-t] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2021] [Revised: 08/31/2021] [Accepted: 10/22/2021] [Indexed: 11/18/2022] Open
Abstract
KNL1 is a large intrinsically disordered kinetochore (KT) protein that recruits spindle assembly checkpoint (SAC) components to mediate SAC signaling. The N-terminal region (NTR) of KNL1 possesses two activities that have been implicated in SAC silencing: microtubule (MT) binding and protein phosphatase 1 (PP1) recruitment. The NTR of Drosophila melanogaster KNL1 (Spc105) has never been shown to bind MTs or to recruit PP1. Furthermore, the phosphoregulatory mechanisms known to control SAC protein binding to KNL1 orthologues is absent in D. melanogaster. Here, these apparent discrepancies are resolved using in vitro and cell-based assays. A phosphoregulatory circuit that utilizes Aurora B kinase promotes SAC protein binding to the central disordered region of Spc105 while the NTR binds directly to MTs in vitro and recruits PP1-87B to KTs in vivo. Live-cell assays employing an optogenetic oligomerization tag and deletion/chimera mutants are used to define the interplay of MT and PP1 binding by Spc105 and the relative contributions of both activities to the kinetics of SAC satisfaction.
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Affiliation(s)
- Margaux R. Audett
- Biology Department, University of Massachusetts, Amherst, Amherst MA 01003
- Molecular and Cellular Biology Graduate Program, University of Massachusetts, Amherst, Amherst MA 01003
| | - Erin L. Johnson
- Biology Department, University of Massachusetts, Amherst, Amherst MA 01003
| | - Jessica M. McGory
- Biology Department, University of Massachusetts, Amherst, Amherst MA 01003
- Molecular and Cellular Biology Graduate Program, University of Massachusetts, Amherst, Amherst MA 01003
| | - Dylan M. Barcelos
- Biology Department, University of Massachusetts, Amherst, Amherst MA 01003
| | - Evelin Oroszne Szalai
- Institute for Life Sciences, School of Biological Sciences, University of Southampton, Southampton SO17 1BJ, UK
| | - Marcin R. Przewloka
- Institute for Life Sciences, School of Biological Sciences, University of Southampton, Southampton SO17 1BJ, UK
| | - Thomas J. Maresca
- Biology Department, University of Massachusetts, Amherst, Amherst MA 01003
- Molecular and Cellular Biology Graduate Program, University of Massachusetts, Amherst, Amherst MA 01003
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6
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Cordeiro MH, Smith RJ, Saurin AT. Kinetochore phosphatases suppress autonomous Polo-like kinase 1 activity to control the mitotic checkpoint. J Cell Biol 2020; 219:e202002020. [PMID: 33125045 PMCID: PMC7608062 DOI: 10.1083/jcb.202002020] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2020] [Revised: 08/20/2020] [Accepted: 10/12/2020] [Indexed: 01/04/2023] Open
Abstract
Local phosphatase regulation is needed at kinetochores to silence the mitotic checkpoint (a.k.a. spindle assembly checkpoint [SAC]). A key event in this regard is the dephosphorylation of MELT repeats on KNL1, which removes SAC proteins from the kinetochore, including the BUB complex. We show here that PP1 and PP2A-B56 phosphatases are primarily required to remove Polo-like kinase 1 (PLK1) from the BUB complex, which can otherwise maintain MELT phosphorylation in an autocatalytic manner. This appears to be their principal role in the SAC because both phosphatases become redundant if PLK1 is inhibited or BUB-PLK1 interaction is prevented. Surprisingly, MELT dephosphorylation can occur normally under these conditions even when the levels or activities of PP1 and PP2A are strongly inhibited at kinetochores. Therefore, these data imply that kinetochore phosphatase regulation is critical for the SAC, but primarily to restrain and extinguish autonomous PLK1 activity. This is likely a conserved feature of the metazoan SAC, since the relevant PLK1 and PP2A-B56 binding motifs have coevolved in the same region on MADBUB homologues.
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Affiliation(s)
| | | | - Adrian T. Saurin
- Division of Cellular Medicine, School of Medicine, University of Dundee, Dundee, UK
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7
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Cunha-Silva S, Osswald M, Goemann J, Barbosa J, Santos LM, Resende P, Bange T, Ferrás C, Sunkel CE, Conde C. Mps1-mediated release of Mad1 from nuclear pores ensures the fidelity of chromosome segregation. J Cell Biol 2020; 219:133569. [PMID: 31913420 PMCID: PMC7054998 DOI: 10.1083/jcb.201906039] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2019] [Revised: 10/20/2019] [Accepted: 11/28/2019] [Indexed: 12/26/2022] Open
Abstract
The spindle assembly checkpoint (SAC) relies on the recruitment of Mad1-C-Mad2 to unattached kinetochores but also on its binding to Megator/Tpr at nuclear pore complexes (NPCs) during interphase. However, the molecular underpinnings controlling the spatiotemporal redistribution of Mad1-C-Mad2 as cells progress into mitosis remain elusive. Here, we show that activation of Mps1 during prophase triggers Mad1 release from NPCs and that this is required for kinetochore localization of Mad1-C-Mad2 and robust SAC signaling. We find that Mps1 phosphorylates Megator/Tpr to reduce its interaction with Mad1 in vitro and in Drosophila cells. Importantly, preventing Mad1 from binding to Megator/Tpr restores Mad1 accumulation at kinetochores, the fidelity of chromosome segregation, and genome stability in larval neuroblasts of mps1-null mutants. Our findings demonstrate that the subcellular localization of Mad1 is tightly coordinated with cell cycle progression by kinetochore-extrinsic activity of Mps1. This ensures that both NPCs in interphase and kinetochores in mitosis can generate anaphase inhibitors to efficiently preserve genomic stability.
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Affiliation(s)
- Sofia Cunha-Silva
- i3S, Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal.,Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, Portugal.,Programa Doutoral em Biologia Molecular e Celular (MCbiology), Instituto de Ciências Biomédicas Abel Salazar, Universidade do Porto, Porto, Portugal
| | - Mariana Osswald
- i3S, Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal.,Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, Portugal
| | - Jana Goemann
- i3S, Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal.,Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, Portugal
| | - João Barbosa
- i3S, Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal.,Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, Portugal
| | - Luis M Santos
- Faculty of Medicine, University of Geneva, Geneva, Switzerland
| | - Pedro Resende
- i3S, Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal.,Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, Portugal
| | - Tanja Bange
- Max-Planck-Institut für Molekulare Physiologie, Dortmund, Germany
| | - Cristina Ferrás
- i3S, Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal.,Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, Portugal
| | - Claudio E Sunkel
- i3S, Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal.,Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, Portugal.,Departamento de Biologia Molecular, Instituto de Ciências Biomédicas Abel Salazar, Porto, Portugal
| | - Carlos Conde
- i3S, Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal.,Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, Portugal
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8
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Ju JQ, Li XH, Pan MH, Xu Y, Xu Y, Sun MH, Sun SC. Mps1 controls spindle assembly, SAC, and DNA repair in the first cleavage of mouse early embryos. J Cell Biochem 2020; 122:290-300. [PMID: 33025669 DOI: 10.1002/jcb.29858] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2020] [Revised: 08/28/2020] [Accepted: 09/14/2020] [Indexed: 11/08/2022]
Abstract
Monopolar spindle-1 (Mps1) is a critical interphase regulator that also involves into the spindle assembly checkpoint for the cell cycle control in both mitosis and meiosis. However, the functions of Mps1 during mouse early embryo development is still unclear. In this study, we reported the important roles of Mps1 in the first cleavage of mouse embryos. Our data indicated that the loss of Mps1 activity caused precocious cleavage of zygotes to 2-cell embryos; however, prolonged culture disturbed the early embryo development to the blastocyst. We found that the spindle organization was disrupted after Mps1 inhibition, and the chromosomes were misaligned in the first cleavage. Moreover, the kinetochore-microtubule attachment was lost and Aurora B failed to accumulate to the kinetochores, indicating that the spindle assembly checkpoint (SAC) was activated. Furthermore, the inhibition of Mps1 activity resulted in an increase of DNA damage, which further induced oxidative stress, showing with positive γ-H2A.X signal and increased reactive oxygen species level. Ultimately, irreparable DNA damage and oxidative stress-activated apoptosis and autophagy, which was confirmed by the positive Annexin-V signal and increased autophagosomes. Taken together, our data indicated that Mps1 played important roles in the control of SAC and DNA repair during mouse early embryo development.
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Affiliation(s)
- Jia-Qian Ju
- College of Animal Science and Technology, Nanjing Agricultural University, Nanjing, China
| | - Xiao-Han Li
- College of Animal Science and Technology, Nanjing Agricultural University, Nanjing, China
| | - Meng-Hao Pan
- College of Animal Science and Technology, Nanjing Agricultural University, Nanjing, China
| | - Yi Xu
- College of Animal Science and Technology, Nanjing Agricultural University, Nanjing, China
| | - Yao Xu
- College of Animal Science and Technology, Nanjing Agricultural University, Nanjing, China
| | - Ming-Hong Sun
- College of Animal Science and Technology, Nanjing Agricultural University, Nanjing, China
| | - Shao-Chen Sun
- College of Animal Science and Technology, Nanjing Agricultural University, Nanjing, China
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9
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Cunha-Silva S, Conde C. From the Nuclear Pore to the Fibrous Corona: A MAD Journey to Preserve Genome Stability. Bioessays 2020; 42:e2000132. [PMID: 32885448 DOI: 10.1002/bies.202000132] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2020] [Revised: 07/22/2020] [Indexed: 11/09/2022]
Abstract
The relationship between kinetochores and nuclear pore complexes (NPCs) is intimate but poorly understood. Several NPC components and associated proteins are relocated to mitotic kinetochores to assist in different activities that ensure faithful chromosome segregation. Such is the case of the Mad1-c-Mad2 complex, the catalytic core of the spindle assembly checkpoint (SAC), a surveillance pathway that delays anaphase until all kinetochores are attached to spindle microtubules. Mad1-c-Mad2 is recruited to discrete domains of unattached kinetochores from where it promotes the rate-limiting step in the assembly of anaphase-inhibitory complexes. SAC proficiency further requires Mad1-c-Mad2 to be anchored at NPCs during interphase. However, the mechanistic relevance of this arrangement for SAC function remains ill-defined. Recent studies uncover the molecular underpinnings that coordinate the release of Mad1-c-Mad2 from NPCs with its prompt recruitment to kinetochores. Here, current knowledge on Mad1-c-Mad2 function and spatiotemporal regulation is reviewed and the critical questions that remain unanswered are highlighted.
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Affiliation(s)
- Sofia Cunha-Silva
- i3S, Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, 4200-135, Portugal.,IBMC, Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, 4200-135, Portugal.,Programa Doutoral em Biologia Molecular e Celular (MCbiology), Instituto de Ciências Biomédicas Abel Salazar (ICBAS), Universidade do Porto, Porto, 4050-313, Portugal
| | - Carlos Conde
- i3S, Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, 4200-135, Portugal.,IBMC, Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, 4200-135, Portugal
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10
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Ólafsson G, Thorpe PH. Polo kinase recruitment via the constitutive centromere-associated network at the kinetochore elevates centromeric RNA. PLoS Genet 2020; 16:e1008990. [PMID: 32810142 PMCID: PMC7455000 DOI: 10.1371/journal.pgen.1008990] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2020] [Revised: 08/28/2020] [Accepted: 07/13/2020] [Indexed: 12/23/2022] Open
Abstract
The kinetochore, a multi-protein complex assembled on centromeres, is essential to segregate chromosomes during cell division. Deficiencies in kinetochore function can lead to chromosomal instability and aneuploidy-a hallmark of cancer cells. Kinetochore function is controlled by recruitment of regulatory proteins, many of which have been documented, however their function often remains uncharacterized and many are yet to be identified. To identify candidates of kinetochore regulation we used a proteome-wide protein association strategy in budding yeast and detected many proteins that are involved in post-translational modifications such as kinases, phosphatases and histone modifiers. We focused on the Polo-like kinase, Cdc5, and interrogated which cellular components were sensitive to constitutive Cdc5 localization. The kinetochore is particularly sensitive to constitutive Cdc5 kinase activity. Targeting Cdc5 to different kinetochore subcomplexes produced diverse phenotypes, consistent with multiple distinct functions at the kinetochore. We show that targeting Cdc5 to the inner kinetochore, the constitutive centromere-associated network (CCAN), increases the levels of centromeric RNA via an SPT4 dependent mechanism.
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Affiliation(s)
- Guðjón Ólafsson
- School of Biological and Chemical Sciences, Queen Mary, University of London, London, United Kingdom
| | - Peter H. Thorpe
- School of Biological and Chemical Sciences, Queen Mary, University of London, London, United Kingdom
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11
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Landmann C, Pierre-Elies P, Goutte-Gattat D, Montembault E, Claverie MC, Royou A. The Mre11-Rad50-Nbs1 complex mediates the robust recruitment of Polo to DNA lesions during mitosis in Drosophila. J Cell Sci 2020; 133:jcs244442. [PMID: 32487663 DOI: 10.1242/jcs.244442] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2020] [Accepted: 05/20/2020] [Indexed: 12/21/2022] Open
Abstract
The DNA damage sensor Mre11-Rad50-Nbs1 complex and Polo kinase are recruited to DNA lesions during mitosis. However, their mechanism of recruitment is elusive. Here, using live-cell imaging combined with micro-irradiation of single chromosomes, we analyze the dynamics of Polo and Mre11 at DNA lesions during mitosis in Drosophila These two proteins display distinct kinetics. Whereas Polo kinetics at double-strand breaks (DSBs) are Cdk1-driven, Mre11 promptly but briefly associates with DSBs regardless of the phase of mitosis and re-associates with DSBs in the proceeding interphase. Mechanistically, Polo kinase activity is required for its own recruitment and that of the mitotic proteins BubR1 and Bub3 to DSBs. Moreover, depletion of Rad50 severely impaired Polo kinetics at mitotic DSBs. Conversely, ectopic tethering of Mre11 to chromatin was sufficient to recruit Polo. Our study highlights a novel pathway that links the DSB sensor Mre11-Rad50-Nbs1 complex and Polo kinase to initiate a prompt, decisive response to the presence of DNA damage during mitosis.
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Affiliation(s)
- Cedric Landmann
- CNRS, UMR5095, University of Bordeaux, European Institute of Chemistry and Biology, 2 rue Robert Escarpit, 33607 Pessac, France
| | - Priscillia Pierre-Elies
- CNRS, UMR5095, University of Bordeaux, European Institute of Chemistry and Biology, 2 rue Robert Escarpit, 33607 Pessac, France
| | - Damien Goutte-Gattat
- CNRS, UMR5095, University of Bordeaux, European Institute of Chemistry and Biology, 2 rue Robert Escarpit, 33607 Pessac, France
| | - Emilie Montembault
- CNRS, UMR5095, University of Bordeaux, European Institute of Chemistry and Biology, 2 rue Robert Escarpit, 33607 Pessac, France
| | - Marie-Charlotte Claverie
- CNRS, UMR5095, University of Bordeaux, European Institute of Chemistry and Biology, 2 rue Robert Escarpit, 33607 Pessac, France
| | - Anne Royou
- CNRS, UMR5095, University of Bordeaux, European Institute of Chemistry and Biology, 2 rue Robert Escarpit, 33607 Pessac, France
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12
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Barbosa J, Conde C, Sunkel C. RZZ-SPINDLY-DYNEIN: you got to keep 'em separated. Cell Cycle 2020; 19:1716-1726. [PMID: 32544383 PMCID: PMC7469663 DOI: 10.1080/15384101.2020.1780382] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2020] [Revised: 06/03/2020] [Accepted: 06/05/2020] [Indexed: 10/24/2022] Open
Abstract
To maintain genome stability, chromosomes must be equally distributed among daughter cells at the end of mitosis. The accuracy of chromosome segregation requires sister-kinetochores to stably attach to microtubules emanating from opposite spindle poles. However, initial kinetochore-microtubule interactions are able to turnover so that defective attachment configurations that typically arise during early mitosis may be corrected. Growing evidence supports a role for the RZZ complex in preventing the stabilization of erroneous kinetochore-microtubule attachments. This inhibitory function of RZZ toward end-on attachments is relieved by DYNEIN-mediated transport of the complex as chromosomes congress and appropriate interactions with microtubules are established. However, it remains unclear how DYNEIN is antagonized to prevent premature RZZ removal. We recently described a new mechanism that sheds new light on this matter. We found that POLO kinase phosphorylates the DYNEIN adaptor SPINDLY to promote the uncoupling between RZZ and DYNEIN. Elevated POLO activity during prometaphase ensures that RZZ is retained at kinetochores to allow the dynamic turnover of kinetochore-microtubule interactions and prevent the stabilization of erroneous attachments. Here, we discuss additional interpretations to explain a model for POLO-dependent regulation of the RZZ-SPINDLY-DYNEIN module during mitosis.
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Affiliation(s)
- João Barbosa
- IBMC - Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, Portugal
- i3S, Instituto de Investigação e Inovação em Saúde da Universidade do Porto, Porto, Portugal
| | - Carlos Conde
- IBMC - Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, Portugal
- i3S, Instituto de Investigação e Inovação em Saúde da Universidade do Porto, Porto, Portugal
| | - Claudio Sunkel
- IBMC - Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, Portugal
- i3S, Instituto de Investigação e Inovação em Saúde da Universidade do Porto, Porto, Portugal
- ICBAS - Instituto de Ciência Biomédicas Abel Salazar da Universidade do Porto, Porto, Portugal
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13
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Matellán L, Monje-Casas F. Regulation of Mitotic Exit by Cell Cycle Checkpoints: Lessons From Saccharomyces cerevisiae. Genes (Basel) 2020; 11:E195. [PMID: 32059558 PMCID: PMC7074328 DOI: 10.3390/genes11020195] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2020] [Revised: 02/07/2020] [Accepted: 02/11/2020] [Indexed: 02/06/2023] Open
Abstract
In order to preserve genome integrity and their ploidy, cells must ensure that the duplicated genome has been faithfully replicated and evenly distributed before they complete their division by mitosis. To this end, cells have developed highly elaborated checkpoints that halt mitotic progression when problems in DNA integrity or chromosome segregation arise, providing them with time to fix these issues before advancing further into the cell cycle. Remarkably, exit from mitosis constitutes a key cell cycle transition that is targeted by the main mitotic checkpoints, despite these surveillance mechanisms being activated by specific intracellular signals and acting at different stages of cell division. Focusing primarily on research carried out using Saccharomyces cerevisiae as a model organism, the aim of this review is to provide a general overview of the molecular mechanisms by which the major cell cycle checkpoints control mitotic exit and to highlight the importance of the proper regulation of this process for the maintenance of genome stability during the distribution of the duplicated chromosomes between the dividing cells.
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Affiliation(s)
| | - Fernando Monje-Casas
- Centro Andaluz de Biología Molecular y Medicina Regenerativa (CABIMER), Spanish National Research Council (CSIC)—University of Seville—University Pablo de Olavide, Avda, Américo Vespucio, 24, 41092 Sevilla, Spain;
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14
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Barbosa J, Martins T, Bange T, Tao L, Conde C, Sunkel C. Polo regulates Spindly to prevent premature stabilization of kinetochore-microtubule attachments. EMBO J 2020; 39:e100789. [PMID: 31849090 PMCID: PMC6960449 DOI: 10.15252/embj.2018100789] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2019] [Revised: 11/26/2019] [Accepted: 12/02/2019] [Indexed: 12/13/2022] Open
Abstract
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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Affiliation(s)
- João Barbosa
- IBMC—Instituto de Biologia Molecular e CelularUniversidade do PortoPortoPortugal
- i3S, Instituto de Investigação e Inovação em Saúde da Universidade do PortoPortoPortugal
| | | | - Tanja Bange
- MPI für molekulare PhysiologieDortmundGermany
| | - Li Tao
- Department of BiologyUniversity of HawaiiHiloHIUSA
| | - Carlos Conde
- IBMC—Instituto de Biologia Molecular e CelularUniversidade do PortoPortoPortugal
- i3S, Instituto de Investigação e Inovação em Saúde da Universidade do PortoPortoPortugal
| | - Claudio Sunkel
- IBMC—Instituto de Biologia Molecular e CelularUniversidade do PortoPortoPortugal
- i3S, Instituto de Investigação e Inovação em Saúde da Universidade do PortoPortoPortugal
- ICBAS—Instituto de Ciência Biomédica de Abel SalazarUniversidade do PortoPortoPortugal
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15
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Cell Cycle Kinase Polo Is Controlled by a Widespread 3' Untranslated Region Regulatory Sequence in Drosophila melanogaster. Mol Cell Biol 2019; 39:MCB.00581-18. [PMID: 31085682 DOI: 10.1128/mcb.00581-18] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2019] [Accepted: 05/04/2019] [Indexed: 01/06/2023] Open
Abstract
Alternative polyadenylation generates transcriptomic diversity, although the physiological impact and regulatory mechanisms involved are still poorly understood. The cell cycle kinase Polo is controlled by alternative polyadenylation in the 3' untranslated region (3'UTR), with critical physiological consequences. Here, we characterized the molecular mechanisms required for polo alternative polyadenylation. We identified a conserved upstream sequence element (USE) close to the polo proximal poly(A) signal. Transgenic flies without this sequence show incorrect selection of polo poly(A) signals with consequent downregulation of Polo expression levels and insufficient/defective activation of Polo kinetochore targets Mps1 and Aurora B. Deletion of the USE results in abnormal mitoses in neuroblasts, revealing a role for this sequence in vivo We found that Hephaestus binds to the USE RNA and that hephaestus mutants display defects in polo alternative polyadenylation concomitant with a striking reduction in Polo protein levels, leading to mitotic errors and aneuploidy. Bioinformatic analyses show that the USE is preferentially localized upstream of noncanonical polyadenylation signals in Drosophila melanogaster genes. Taken together, our results revealed the molecular mechanisms involved in polo alternative polyadenylation, with remarkable physiological functions in Polo expression and activity at the kinetochores, and disclosed a new in vivo function for USEs in Drosophila melanogaster.
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16
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Qi F, Zhou J, Liu M. Microtubule-interfering agents, spindle defects, and interkinetochore tension. J Cell Physiol 2019; 235:26-30. [PMID: 31219174 DOI: 10.1002/jcp.28978] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2019] [Accepted: 05/29/2019] [Indexed: 01/29/2023]
Abstract
Microtubule-interfering agents have been very useful both as biological tools in studying mitosis and as chemotherapeutic agents against cancer. It remains poorly understood how these agents converge on the spindle assembly checkpoint (SAC) to halt mitotic progression, while inhibiting microtubule dynamics by different mechanisms. Cells arrested at mitosis by various microtubule-interfering agents exhibit strikingly different defects in the mitotic spindle. However, all the arrested cells possess the 3F3/2 phosphoepitope at the sister kinetochores of chromosomes, indicating the decrease of tension across the paired kinetochores. In addition, microtubule-interfering agents result in a comparable reduction in the distance between sister kinetochores, suggesting that these agents decrease interkinetochore tension to similar degrees. Here, we discuss recent progress that suggests impairment of kinetochore-microtubule attachment and reduction of interkinetochore tension as common mechanisms underlying the persistent SAC activation in response to diverse microtubule-interfering agents.
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Affiliation(s)
- Feifei Qi
- Shandong Provincial Key Laboratory of Animal Resistance Biology, Collaborative Innovation Center of Cell Biology in Universities of Shandong, Institute of Biomedical Sciences, College of Life Sciences, Shandong Normal University, Jinan, Shandong, China
| | - Jun Zhou
- Shandong Provincial Key Laboratory of Animal Resistance Biology, Collaborative Innovation Center of Cell Biology in Universities of Shandong, Institute of Biomedical Sciences, College of Life Sciences, Shandong Normal University, Jinan, Shandong, China
| | - Min Liu
- Shandong Provincial Key Laboratory of Animal Resistance Biology, Collaborative Innovation Center of Cell Biology in Universities of Shandong, Institute of Biomedical Sciences, College of Life Sciences, Shandong Normal University, Jinan, Shandong, China
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17
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Wang LI, Das A, McKim KS. Sister centromere fusion during meiosis I depends on maintaining cohesins and destabilizing microtubule attachments. PLoS Genet 2019; 15:e1008072. [PMID: 31150390 PMCID: PMC6581285 DOI: 10.1371/journal.pgen.1008072] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2019] [Revised: 06/18/2019] [Accepted: 05/16/2019] [Indexed: 11/26/2022] Open
Abstract
Sister centromere fusion is a process unique to meiosis that promotes co-orientation of the sister kinetochores, ensuring they attach to microtubules from the same pole during metaphase I. We have found that the kinetochore protein SPC105R/KNL1 and Protein Phosphatase 1 (PP1-87B) regulate sister centromere fusion in Drosophila oocytes. The analysis of these two proteins, however, has shown that two independent mechanisms maintain sister centromere fusion. Maintenance of sister centromere fusion by SPC105R depends on Separase, suggesting cohesin proteins must be maintained at the core centromeres. In contrast, maintenance of sister centromere fusion by PP1-87B does not depend on either Separase or WAPL. Instead, PP1-87B maintains sister centromeres fusion by regulating microtubule dynamics. We demonstrate that this regulation is through antagonizing Polo kinase and BubR1, two proteins known to promote stability of kinetochore-microtubule (KT-MT) attachments, suggesting that PP1-87B maintains sister centromere fusion by inhibiting stable KT-MT attachments. Surprisingly, C(3)G, the transverse element of the synaptonemal complex (SC), is also required for centromere separation in Pp1-87B RNAi oocytes. This is evidence for a functional role of centromeric SC in the meiotic divisions, that might involve regulating microtubule dynamics. Together, we propose two mechanisms maintain co-orientation in Drosophila oocytes: one involves SPC105R to protect cohesins at sister centromeres and another involves PP1-87B to regulate spindle forces at end-on attachments.
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Affiliation(s)
- Lin-Ing Wang
- Waksman Institute and Department of Genetics, Rutgers, the State University of New Jersey, Piscataway, New Jersey, United States of America
| | - Arunika Das
- Waksman Institute and Department of Genetics, Rutgers, the State University of New Jersey, Piscataway, New Jersey, United States of America
| | - Kim S. McKim
- Waksman Institute and Department of Genetics, Rutgers, the State University of New Jersey, Piscataway, New Jersey, United States of America
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18
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Osswald M, Santos AF, Morais-de-Sá E. Light-Induced Protein Clustering for Optogenetic Interference and Protein Interaction Analysis in Drosophila S2 Cells. Biomolecules 2019; 9:biom9020061. [PMID: 30759894 PMCID: PMC6406598 DOI: 10.3390/biom9020061] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2018] [Revised: 01/30/2019] [Accepted: 01/30/2019] [Indexed: 12/19/2022] Open
Abstract
Drosophila Schneider 2 (S2) cells are a simple and powerful system commonly used in cell biology because they are well suited for high resolution microscopy and RNAi-mediated depletion. However, understanding dynamic processes, such as cell division, also requires methodology to interfere with protein function with high spatiotemporal control. In this research study, we report the adaptation of an optogenetic tool to Drosophila S2 cells. Light-activated reversible inhibition by assembled trap (LARIAT) relies on the rapid light-dependent heterodimerization between cryptochrome 2 (CRY2) and cryptochrome-interacting bHLH 1 (CIB1) to form large protein clusters. An anti-green fluorescent protein (GFP) nanobody fused with CRY2 allows this method to quickly trap any GFP-tagged protein in these light-induced protein clusters. We evaluated clustering kinetics in response to light for different LARIAT modules, and showed the ability of GFP-LARIAT to inactivate the mitotic protein Mps1 and to disrupt the membrane localization of the polarity regulator Lethal Giant Larvae (Lgl). Moreover, we validated light-induced co-clustering assays to assess protein-protein interactions in S2 cells. In conclusion, GFP-based LARIAT is a versatile tool to answer different biological questions, since it enables probing of dynamic processes and protein-protein interactions with high spatiotemporal resolution in Drosophila S2 cells.
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Affiliation(s)
- Mariana Osswald
- Epithelial Polarity and Cell Division, i3S, Instituto de Investigação e Inovação em Saúde, Universidade do Porto, 4200-135 Porto, Portugal.
- IBMC, Instituto de Biologia Molecular e Celular, Universidade do Porto, 4200-135 Porto, Portugal.
| | - A Filipa Santos
- Epithelial Polarity and Cell Division, i3S, Instituto de Investigação e Inovação em Saúde, Universidade do Porto, 4200-135 Porto, Portugal.
- IBMC, Instituto de Biologia Molecular e Celular, Universidade do Porto, 4200-135 Porto, Portugal.
| | - Eurico Morais-de-Sá
- Epithelial Polarity and Cell Division, i3S, Instituto de Investigação e Inovação em Saúde, Universidade do Porto, 4200-135 Porto, Portugal.
- IBMC, Instituto de Biologia Molecular e Celular, Universidade do Porto, 4200-135 Porto, Portugal.
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19
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Moura M, Conde C. Phosphatases in Mitosis: Roles and Regulation. Biomolecules 2019; 9:E55. [PMID: 30736436 PMCID: PMC6406801 DOI: 10.3390/biom9020055] [Citation(s) in RCA: 47] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2018] [Revised: 01/31/2019] [Accepted: 02/01/2019] [Indexed: 02/07/2023] Open
Abstract
Mitosis requires extensive rearrangement of cellular architecture and of subcellular structures so that replicated chromosomes can bind correctly to spindle microtubules and segregate towards opposite poles. This process originates two new daughter nuclei with equal genetic content and relies on highly-dynamic and tightly regulated phosphorylation of numerous cell cycle proteins. A burst in protein phosphorylation orchestrated by several conserved kinases occurs as cells go into and progress through mitosis. The opposing dephosphorylation events are catalyzed by a small set of protein phosphatases, whose importance for the accuracy of mitosis is becoming increasingly appreciated. This review will focus on the established and emerging roles of mitotic phosphatases, describe their structural and biochemical properties, and discuss recent advances in understanding the regulation of phosphatase activity and function.
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Affiliation(s)
- Margarida Moura
- IBMC-Instituto de Biologia Molecular e Celular, Universidade do Porto, 4200-135 Porto, Portugal.
- i3S-Instituto de Investigação e Inovação em Saúde da Universidade do Porto, 4200-135, Porto, Portugal.
- Programa Doutoral em Biologia Molecular e Celular (MCbiology), Instituto de Ciências Biomédicas Abel Salazar (ICBAS), Universidade do Porto, 4050-313 Porto, Portugal.
| | - Carlos Conde
- IBMC-Instituto de Biologia Molecular e Celular, Universidade do Porto, 4200-135 Porto, Portugal.
- i3S-Instituto de Investigação e Inovação em Saúde da Universidade do Porto, 4200-135, Porto, Portugal.
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20
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Resende LP, Monteiro A, Brás R, Lopes T, Sunkel CE. Aneuploidy in intestinal stem cells promotes gut dysplasia in Drosophila. J Cell Biol 2018; 217:3930-3946. [PMID: 30282810 PMCID: PMC6219720 DOI: 10.1083/jcb.201804205] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2018] [Revised: 08/01/2018] [Accepted: 08/31/2018] [Indexed: 12/17/2022] Open
Abstract
Aneuploidy is associated with different human diseases including cancer. However, different cell types appear to respond differently to aneuploidy, either by promoting tumorigenesis or causing cell death. We set out to study the behavior of adult Drosophila melanogaster intestinal stem cells (ISCs) after induction of chromosome missegregation either by abrogation of the spindle assembly checkpoint or through kinetochore disruption or centrosome amplification. These conditions induce moderate levels of aneuploidy in ISCs, and we find no evidence of apoptosis. Instead, we observe a significant accumulation of ISCs associated with increased stem cell proliferation and an excess of enteroendocrine cells. Moreover, aneuploidy causes up-regulation of the JNK pathway throughout the posterior midgut, and specific inhibition of JNK signaling in ISCs is sufficient to prevent dysplasia. Our findings highlight the importance of understanding the behavior of different stem cell populations to aneuploidy and how these can act as reservoirs for genomic alterations that can lead to tissue pathologies.
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Affiliation(s)
- Luís Pedro Resende
- Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal
- Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, Portugal
| | - Augusta Monteiro
- Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal
- Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, Portugal
| | - Rita Brás
- Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal
- Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, Portugal
| | - Tatiana Lopes
- Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal
- Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, Portugal
| | - Claudio E Sunkel
- Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal
- Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, Portugal
- Instituto de Ciências Biomédicas de Abel Salazar, Universidade do Porto, Porto, Portugal
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21
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Combes G, Alharbi I, Braga LG, Elowe S. Playing polo during mitosis: PLK1 takes the lead. Oncogene 2017; 36:4819-4827. [PMID: 28436952 DOI: 10.1038/onc.2017.113] [Citation(s) in RCA: 110] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2017] [Revised: 03/16/2017] [Accepted: 03/18/2017] [Indexed: 12/18/2022]
Abstract
Polo-like kinase 1 (PLK1), the prototypical member of the polo-like family of serine/threonine kinases, is a pivotal regulator of mitosis and cytokinesis in eukaryotes. Many layers of regulation have evolved to target PLK1 to different subcellular structures and to its various mitotic substrates in line with its numerous functions during mitosis. Collective work is starting to illuminate an important set of substrates for PLK1: the mitotic kinases that together ensure the fidelity of the cell division process. Amongst these, recent developments argue that PLK1 regulates the activity of the histone kinases Aurora B and Haspin to define centromere identity, of MPS1 to initiate spindle checkpoint signaling, and of BUB1 and its pseudokinase paralog BUBR1 to coordinate spindle checkpoint activation and inactivation. Here, we review the recent work describing the regulation of these kinases by PLK1. We highlight common themes throughout and argue that a major mitotic function of PLK1 is as a master regulator of these key kinases.
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Affiliation(s)
- G Combes
- Program in Molecular and Cellular biology, Faculty of Medicine, Université Laval, Quebec City, Quebec, Canada
- Axe of Reproduction, Mother and Youth Health, CHU de Québec Research Centre, Quebec City, Quebec, Canada
| | - I Alharbi
- Program in Molecular and Cellular biology, Faculty of Medicine, Université Laval, Quebec City, Quebec, Canada
- Axe of Reproduction, Mother and Youth Health, CHU de Québec Research Centre, Quebec City, Quebec, Canada
| | - L G Braga
- Program in Molecular and Cellular biology, Faculty of Medicine, Université Laval, Quebec City, Quebec, Canada
- Axe of Reproduction, Mother and Youth Health, CHU de Québec Research Centre, Quebec City, Quebec, Canada
| | - S Elowe
- Program in Molecular and Cellular biology, Faculty of Medicine, Université Laval, Quebec City, Quebec, Canada
- Axe of Reproduction, Mother and Youth Health, CHU de Québec Research Centre, Quebec City, Quebec, Canada
- Department of Pediatrics, Faculty of Medicine, Université Laval, Quebec City, Quebec, Canada
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22
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Moura M, Osswald M, Leça N, Barbosa J, Pereira AJ, Maiato H, Sunkel CE, Conde C. Protein Phosphatase 1 inactivates Mps1 to ensure efficient Spindle Assembly Checkpoint silencing. eLife 2017; 6. [PMID: 28463114 PMCID: PMC5433843 DOI: 10.7554/elife.25366] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2017] [Accepted: 04/29/2017] [Indexed: 12/13/2022] Open
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. DOI:http://dx.doi.org/10.7554/eLife.25366.001
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Affiliation(s)
- Margarida Moura
- i3S, Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal.,Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, Portugal
| | - Mariana Osswald
- i3S, Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal.,Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, Portugal
| | - Nelson Leça
- i3S, Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal.,Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, Portugal
| | - João Barbosa
- i3S, Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal.,Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, Portugal
| | - António J Pereira
- i3S, Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal.,Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, Portugal
| | - Helder Maiato
- i3S, Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal.,Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, Portugal.,Departamento de Biomedicina, Unidade de Biologia Experimental, FMUP - Faculdade de Medicina da Universidade do Porto, Porto, Portugal
| | - Claudio E Sunkel
- i3S, Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal.,Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, Portugal.,Departamento de Biologia Molecular, ICBAS - Instituto de Ciências Biomédicas Abel Salazar, Porto, Portugal
| | - Carlos Conde
- i3S, Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal.,Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, Portugal
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23
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Calpain A controls mitotic synchrony in the Drosophila blastoderm embryo. Mech Dev 2017; 144:141-149. [DOI: 10.1016/j.mod.2016.05.005] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2016] [Revised: 05/27/2016] [Accepted: 05/31/2016] [Indexed: 01/10/2023]
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24
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Aurora-A promotes the establishment of spindle assembly checkpoint by priming the Haspin-Aurora-B feedback loop in late G2 phase. Cell Discov 2017; 3:16049. [PMID: 28101375 PMCID: PMC5223110 DOI: 10.1038/celldisc.2016.49] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2016] [Accepted: 11/22/2016] [Indexed: 12/11/2022] Open
Abstract
Aurora-A kinase functions mainly in centrosome maturation, separation and spindle formation. It has also been found to be amplified or overexpressed in a range of solid tumors, which is linked with tumor progression and poor prognosis. Importantly, Aurora-A inhibitors are being studied in a number of ongoing clinical trials. However, whether and how Aurora-A has a role in the regulation of the mitotic checkpoint is controversial. Additionally, the function of nuclear-accumulated Aurora-A in late G2 phase is not clear. Here we show that knockout, inhibition or blockade of the nuclear entry of Aurora-A severely decreased the centromere localization of Aurora-B and the phosphorylation of histone H3 threonine 3 (H3T3-ph) mediated by the kinase Haspin in late G2 phase. We further reveal that nuclear-accumulated Aurora-A phosphorylates Haspin at multiple sites at its N-terminus and that this promotes H3T3-ph and the rapid recruitment to the centromere of the chromosomal passenger complex. In addition, Aurora-A facilitates the association of Aurora-B with their common substrates: Haspin and Plk1. Notably, these functions of Aurora-A are mostly independent of Plk1. Thus we demonstrate that, in late G2 and prophase, Aurora-A phosphorylates Haspin to trigger the Haspin-H3T3-ph-Aurora-B positive feedback loop that supports the timely establishment of the chromosomal passenger complex and the mitotic checkpoint before spindle assembly.
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25
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Restuccia A, Yang F, Chen C, Lu L, Dai W. Mps1 is SUMO-modified during the cell cycle. Oncotarget 2016; 7:3158-70. [PMID: 26675261 PMCID: PMC4823097 DOI: 10.18632/oncotarget.6552] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2015] [Accepted: 11/21/2015] [Indexed: 11/30/2022] Open
Abstract
Mps1 is a dual specificity protein kinase that regulates the spindle assembly checkpoint and mediates proper microtubule attachment to chromosomes during mitosis. However, the molecular mechanism that controls Mps1 protein level and its activity during the cell cycle remains unclear. Given that sumoylation plays an important role in mitotic progression, we investigated whether Mps1 was SUMO-modified and whether sumoylation affects its activity in mitosis. Our results showed that Mps1 was sumoylated in both asynchronized and mitotic cell populations. Mps1 was modified by both SUMO-1 and SUMO-2. Our further studies revealed that lysine residues including K71, K287, K367 and K471 were essential for Mps1 sumoylation. Sumoylation appeared to play a role in mediating kinetochore localization of Mps1, thus affecting normal mitotic progression. Furthermore, SUMO-resistant mutants of Mps1 interacted with BubR1 more efficiently than it did with the wild-type control. Combined, our results indicate that Mps1 is SUMO-modified that plays an essential role in regulating Mps1 functions during mitosis.
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Affiliation(s)
- Agnese Restuccia
- Division of Virus-Associated Carcinogenesis, German Cancer Research Center, Heidelberg, Germany
| | - Feikun Yang
- Departments of Environmental Medicine, Biochemistry and Molecular Pharmacology, New York University Langone Medical Center, Tuxedo Park, NY, USA
| | - Changyan Chen
- Center for Drug Discovery, Northeastern University, Boston, MA, USA
| | - Lou Lu
- Division of Molecular Medicine, Department of Medicine, David Geffen School of Medicine, University of California Los Angeles, Torrance, CA, USA
| | - Wei Dai
- Departments of Environmental Medicine, Biochemistry and Molecular Pharmacology, New York University Langone Medical Center, Tuxedo Park, NY, USA
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26
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Manic G, Corradi F, Sistigu A, Siteni S, Vitale I. Molecular Regulation of the Spindle Assembly Checkpoint by Kinases and Phosphatases. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2016; 328:105-161. [PMID: 28069132 DOI: 10.1016/bs.ircmb.2016.08.004] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The spindle assembly checkpoint (SAC) is a surveillance mechanism contributing to the preservation of genomic stability by monitoring the microtubule attachment to, and/or the tension status of, each kinetochore during mitosis. The SAC halts metaphase to anaphase transition in the presence of unattached and/or untensed kinetochore(s) by releasing the mitotic checkpoint complex (MCC) from these improperly-oriented kinetochores to inhibit the anaphase-promoting complex/cyclosome (APC/C). The reversible phosphorylation of a variety of substrates at the kinetochore by antagonistic kinases and phosphatases is one major signaling mechanism for promptly turning on or turning off the SAC. In such a complex network, some kinases act at the apex of the SAC cascade by either generating (monopolar spindle 1, MPS1/TTK and likely polo-like kinase 1, PLK1), or contributing to generate (Aurora kinase B) kinetochore phospho-docking sites for the hierarchical recruitment of the SAC proteins. Aurora kinase B, MPS1 and budding uninhibited by benzimidazoles 1 (BUB1) also promote sister chromatid biorientation by modulating kinetochore microtubule stability. Moreover, MPS1, BUB1, and PLK1 seem to play key roles in APC/C inhibition by mechanisms dependent and/or independent on MCC assembly. The protein phosphatase 1 and 2A (PP1 and PP2A) are recruited to kinetochores to oppose kinase activity. These phosphatases reverse the phosphorylation of kinetochore targets promoting the microtubule attachment stabilization, sister kinetochore biorientation and SAC silencing. The kinase-phosphatase network is crucial as it renders the SAC a dynamic, graded-signaling, high responsive, and robust process thereby ensuring timely anaphase onset and preventing the generation of proneoplastic aneuploidy.
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Affiliation(s)
- G Manic
- Regina Elena National Cancer Institute, Rome, Italy.
| | - F Corradi
- Department of Biology, University of Rome "Tor Vergata", Rome, Italy
| | - A Sistigu
- Regina Elena National Cancer Institute, Rome, Italy
| | - S Siteni
- Regina Elena National Cancer Institute, Rome, Italy; Department of Biology, University of Rome "Roma Tre", Rome, Italy
| | - I Vitale
- Regina Elena National Cancer Institute, Rome, Italy; Department of Biology, University of Rome "Tor Vergata", Rome, Italy.
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27
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Zich J, May K, Paraskevopoulos K, Sen O, Syred HM, van der Sar S, Patel H, Moresco JJ, Sarkeshik A, Yates JR, Rappsilber J, Hardwick KG. Mps1Mph1 Kinase Phosphorylates Mad3 to Inhibit Cdc20Slp1-APC/C and Maintain Spindle Checkpoint Arrests. PLoS Genet 2016; 12:e1005834. [PMID: 26882497 PMCID: PMC4755545 DOI: 10.1371/journal.pgen.1005834] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2015] [Accepted: 01/09/2016] [Indexed: 01/01/2023] Open
Abstract
The spindle checkpoint is a mitotic surveillance system which ensures equal segregation of sister chromatids. It delays anaphase onset by inhibiting the action of the E3 ubiquitin ligase known as the anaphase promoting complex or cyclosome (APC/C). Mad3/BubR1 is a key component of the mitotic checkpoint complex (MCC) which binds and inhibits the APC/C early in mitosis. Mps1Mph1 kinase is critical for checkpoint signalling and MCC-APC/C inhibition, yet few substrates have been identified. Here we identify Mad3 as a substrate of fission yeast Mps1Mph1 kinase. We map and mutate phosphorylation sites in Mad3, producing mutants that are targeted to kinetochores and assembled into MCC, yet display reduced APC/C binding and are unable to maintain checkpoint arrests. We show biochemically that Mad3 phospho-mimics are potent APC/C inhibitors in vitro, demonstrating that Mad3p modification can directly influence Cdc20Slp1-APC/C activity. This genetic dissection of APC/C inhibition demonstrates that Mps1Mph1 kinase-dependent modifications of Mad3 and Mad2 act in a concerted manner to maintain spindle checkpoint arrests. When cells divide they need to ensure that a complete copy of their genetic material is transmitted to both daughter cells. Cells have evolved many controls to ensure that every division is carried out with very high fidelity. The spindle checkpoint is one such control, which acts as a surveillance system during mitosis. Defects in this checkpoint control lead to unequal segregation of DNA/chromosomes, termed aneuploidy, which is responsible for human birth defects and is very common in tumour cells. The molecular components of the spindle checkpoint, identified initially through yeast genetics, include several protein kinases. Surprisingly few of their substrates have been identified. Here we identify the checkpoint protein Mad3 as an important substrate of the Mps1Mph1 kinase. We show that Mps1Mph1-dependent modification of Mad3 and Mad2 acts to delay cell division in situations where the genetic material would not be equally inherited by daughter cells. This delay enables the cell to correct any problems within the division machinery and thus avoid aneuploidy.
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Affiliation(s)
- Judith Zich
- Wellcome Trust Centre for Cell Biology, Institute of Cell Biology, University of Edinburgh, Edinburgh, United Kingdom
| | - Karen May
- Wellcome Trust Centre for Cell Biology, Institute of Cell Biology, University of Edinburgh, Edinburgh, United Kingdom
| | - Konstantinos Paraskevopoulos
- Wellcome Trust Centre for Cell Biology, Institute of Cell Biology, University of Edinburgh, Edinburgh, United Kingdom
| | - Onur Sen
- Wellcome Trust Centre for Cell Biology, Institute of Cell Biology, University of Edinburgh, Edinburgh, United Kingdom
| | - Heather M. Syred
- Wellcome Trust Centre for Cell Biology, Institute of Cell Biology, University of Edinburgh, Edinburgh, United Kingdom
| | - Sjaak van der Sar
- Wellcome Trust Centre for Cell Biology, Institute of Cell Biology, University of Edinburgh, Edinburgh, United Kingdom
| | - Hitesh Patel
- Edinburgh Cancer Research UK Centre, Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh, United Kingdom
| | - James J. Moresco
- Scripps Research Institute, La Jolla, California, United States of America
| | - Ali Sarkeshik
- Scripps Research Institute, La Jolla, California, United States of America
| | - John R. Yates
- Scripps Research Institute, La Jolla, California, United States of America
| | - Juri Rappsilber
- Wellcome Trust Centre for Cell Biology, Institute of Cell Biology, University of Edinburgh, Edinburgh, United Kingdom
- Department of Bioanalytics, Institute of Biotechnology, Technische Universitat Berlin, Berlin, Germany
| | - Kevin G. Hardwick
- Wellcome Trust Centre for Cell Biology, Institute of Cell Biology, University of Edinburgh, Edinburgh, United Kingdom
- * E-mail:
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28
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Derive N, Landmann C, Montembault E, Claverie MC, Pierre-Elies P, Goutte-Gattat D, Founounou N, McCusker D, Royou A. Bub3-BubR1-dependent sequestration of Cdc20Fizzy at DNA breaks facilitates the correct segregation of broken chromosomes. J Cell Biol 2016; 211:517-32. [PMID: 26553926 PMCID: PMC4639866 DOI: 10.1083/jcb.201504059] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
BubR1 depends on its association with Bub3 to localize on DNA breaks during mitosis, where it sequesters Cdc20Fizzy and induces the inhibition of the APC/C locally, promoting the faithful segregation of broken chromatids. The presence of DNA double-strand breaks during mitosis is particularly challenging for the cell, as it produces broken chromosomes lacking a centromere. This situation can cause genomic instability resulting from improper segregation of the broken fragments into daughter cells. We recently uncovered a process by which broken chromosomes are faithfully transmitted via the BubR1-dependent tethering of the two broken chromosome ends. However, the mechanisms underlying BubR1 recruitment and function on broken chromosomes were largely unknown. We show that BubR1 requires interaction with Bub3 to localize on the broken chromosome fragments and to mediate their proper segregation. We also find that Cdc20, a cofactor of the E3 ubiquitin ligase anaphase-promoting complex/cyclosome (APC/C), accumulates on DNA breaks in a BubR1 KEN box–dependent manner. A biosensor for APC/C activity demonstrates a BubR1-dependent local inhibition of APC/C around the segregating broken chromosome. We therefore propose that the Bub3–BubR1 complex on broken DNA inhibits the APC/C locally via the sequestration of Cdc20, thus promoting proper transmission of broken chromosomes.
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Affiliation(s)
- Nicolas Derive
- Université de Bordeaux, Institut Européen de Chimie et Biologie, Institut de Biochimie et Génétique Cellulaires, Unité Mixte de Recherche 5095, 33607 Pessac, France Centre National de la Recherche Scientifique, Institut Européen de Chimie et Biologie, Institut de Biochimie et Génétique Cellulaires, Unité Mixte de Recherche 5095, 33607 Pessac, France
| | - Cedric Landmann
- Université de Bordeaux, Institut Européen de Chimie et Biologie, Institut de Biochimie et Génétique Cellulaires, Unité Mixte de Recherche 5095, 33607 Pessac, France Centre National de la Recherche Scientifique, Institut Européen de Chimie et Biologie, Institut de Biochimie et Génétique Cellulaires, Unité Mixte de Recherche 5095, 33607 Pessac, France
| | - Emilie Montembault
- Université de Bordeaux, Institut Européen de Chimie et Biologie, Institut de Biochimie et Génétique Cellulaires, Unité Mixte de Recherche 5095, 33607 Pessac, France Centre National de la Recherche Scientifique, Institut Européen de Chimie et Biologie, Institut de Biochimie et Génétique Cellulaires, Unité Mixte de Recherche 5095, 33607 Pessac, France
| | - Marie-Charlotte Claverie
- Université de Bordeaux, Institut Européen de Chimie et Biologie, Institut de Biochimie et Génétique Cellulaires, Unité Mixte de Recherche 5095, 33607 Pessac, France Centre National de la Recherche Scientifique, Institut Européen de Chimie et Biologie, Institut de Biochimie et Génétique Cellulaires, Unité Mixte de Recherche 5095, 33607 Pessac, France
| | - Priscillia Pierre-Elies
- Université de Bordeaux, Institut Européen de Chimie et Biologie, Institut de Biochimie et Génétique Cellulaires, Unité Mixte de Recherche 5095, 33607 Pessac, France Centre National de la Recherche Scientifique, Institut Européen de Chimie et Biologie, Institut de Biochimie et Génétique Cellulaires, Unité Mixte de Recherche 5095, 33607 Pessac, France
| | - Damien Goutte-Gattat
- Université de Bordeaux, Institut Européen de Chimie et Biologie, Institut de Biochimie et Génétique Cellulaires, Unité Mixte de Recherche 5095, 33607 Pessac, France Centre National de la Recherche Scientifique, Institut Européen de Chimie et Biologie, Institut de Biochimie et Génétique Cellulaires, Unité Mixte de Recherche 5095, 33607 Pessac, France
| | - Nabila Founounou
- Université de Bordeaux, Institut Européen de Chimie et Biologie, Institut de Biochimie et Génétique Cellulaires, Unité Mixte de Recherche 5095, 33607 Pessac, France Centre National de la Recherche Scientifique, Institut Européen de Chimie et Biologie, Institut de Biochimie et Génétique Cellulaires, Unité Mixte de Recherche 5095, 33607 Pessac, France
| | - Derek McCusker
- Université de Bordeaux, Institut Européen de Chimie et Biologie, Institut de Biochimie et Génétique Cellulaires, Unité Mixte de Recherche 5095, 33607 Pessac, France Centre National de la Recherche Scientifique, Institut Européen de Chimie et Biologie, Institut de Biochimie et Génétique Cellulaires, Unité Mixte de Recherche 5095, 33607 Pessac, France
| | - Anne Royou
- Université de Bordeaux, Institut Européen de Chimie et Biologie, Institut de Biochimie et Génétique Cellulaires, Unité Mixte de Recherche 5095, 33607 Pessac, France Centre National de la Recherche Scientifique, Institut Européen de Chimie et Biologie, Institut de Biochimie et Génétique Cellulaires, Unité Mixte de Recherche 5095, 33607 Pessac, France
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29
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O'Connor A, Maffini S, Rainey MD, Kaczmarczyk A, Gaboriau D, Musacchio A, Santocanale C. Requirement for PLK1 kinase activity in the maintenance of a robust spindle assembly checkpoint. Biol Open 2015; 5:11-9. [PMID: 26685311 PMCID: PMC4728306 DOI: 10.1242/bio.014969] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
During mitotic arrest induced by microtubule targeting drugs, the weakening of the spindle assembly checkpoint (SAC) allows cells to progress through the cell cycle without chromosome segregation occurring. PLK1 kinase plays a major role in mitosis and emerging evidence indicates that PLK1 is also involved in establishing the checkpoint and maintaining SAC signalling. However, mechanistically, the role of PLK1 in the SAC is not fully understood, with several recent reports indicating that it can cooperate with either one of the major checkpoint kinases, Aurora B or MPS1. In this study, we assess the role of PLK1 in SAC maintenance. We find that in nocodazole-arrested U2OS cells, PLK1 activity is continuously required for maintaining Aurora B protein localisation and activity at kinetochores. Consistent with published data we find that upon PLK1 inhibition, phosphoThr3-H3, a marker of Haspin activity, is reduced. Intriguingly, Aurora B inhibition causes PLK1 to relocalise from kinetochores into fewer and much larger foci, possibly due to incomplete recruitment of outer kinetochore proteins. Importantly, PLK1 inhibition, together with partial inhibition of Aurora B, allows efficient SAC override to occur. This phenotype is more pronounced than the phenotype observed by combining the same PLK1 inhibitors with partial MPS1 inhibition. We also find that PLK1 inhibition does not obviously cooperate with Haspin inhibition to promote SAC override. These results indicate that PLK1 is directly involved in maintaining efficient SAC signalling, possibly by cooperating in a positive feedback loop with Aurora B, and that partially redundant mechanisms exist which reinforce the SAC.
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Affiliation(s)
- Aisling O'Connor
- Centre for Chromosome Biology, School of Natural Sciences, National University of Ireland Galway, Galway, Ireland
| | - Stefano Maffini
- Max-Planck Institute of Molecular Physiology, Department of Mechanistic Cell Biology, Dortmund 44227, Germany
| | - Michael D Rainey
- Centre for Chromosome Biology, School of Natural Sciences, National University of Ireland Galway, Galway, Ireland
| | - Agnieszka Kaczmarczyk
- Centre for Chromosome Biology, School of Natural Sciences, National University of Ireland Galway, Galway, Ireland
| | - David Gaboriau
- Centre for Chromosome Biology, School of Natural Sciences, National University of Ireland Galway, Galway, Ireland
| | - Andrea Musacchio
- Max-Planck Institute of Molecular Physiology, Department of Mechanistic Cell Biology, Dortmund 44227, Germany Centre for Medical Biotechnology, Faculty of Biology, University Duisburg-Essen, Universitätsstrasse, Essen 45141, Germany
| | - Corrado Santocanale
- Centre for Chromosome Biology, School of Natural Sciences, National University of Ireland Galway, Galway, Ireland
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30
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Peng F, Zhao Y, Huang X, Chen C, Sun L, Zhuang L, Xue L. Loss of Polo ameliorates APP-induced Alzheimer's disease-like symptoms in Drosophila. Sci Rep 2015; 5:16816. [PMID: 26597721 PMCID: PMC4657023 DOI: 10.1038/srep16816] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2015] [Accepted: 10/15/2015] [Indexed: 12/13/2022] Open
Abstract
The amyloid precursor protein (APP) has been implicated in the pathogenesis of Alzheimer’s disease (AD). Despite extensive studies, little is known about the regulation of APP’s functions in vivo. Here we report that expression of human APP in Drosophila, in the same temporal-spatial pattern as its homolog APPL, induced morphological defects in wings and larval NMJ, larva and adult locomotion dysfunctions, male choice disorder and lifespan shortening. To identify additional genes that modulate APP functions, we performed a genetic screen and found that loss of Polo, a key regulator of cell cycle, partially suppressed APP-induced morphological and behavioral defects in larval and adult stages. Finally, we showed that eye-specific expression of APP induced retina degeneration and cell cycle re-entry, both phenotypes were mildly ameliorated by loss of Polo. These results suggest Polo is an important in vivo regulator of the pathological functions of APP, and provide insight into the role of cell cycle re-entry in AD pathogenesis.
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Affiliation(s)
- Fei Peng
- Institute of Intervention Vessel, Shanghai 10th People's Hospital, Shanghai Key Laboratory of Signaling and Disease Research, School of Life Science and Technology, Tongji University, 1239 Siping Road, Shanghai 200092, China
| | - Yu Zhao
- Institute of Intervention Vessel, Shanghai 10th People's Hospital, Shanghai Key Laboratory of Signaling and Disease Research, School of Life Science and Technology, Tongji University, 1239 Siping Road, Shanghai 200092, China
| | - Xirui Huang
- Institute of Intervention Vessel, Shanghai 10th People's Hospital, Shanghai Key Laboratory of Signaling and Disease Research, School of Life Science and Technology, Tongji University, 1239 Siping Road, Shanghai 200092, China
| | - Changyan Chen
- Institute of Intervention Vessel, Shanghai 10th People's Hospital, Shanghai Key Laboratory of Signaling and Disease Research, School of Life Science and Technology, Tongji University, 1239 Siping Road, Shanghai 200092, China
| | - Lili Sun
- School of Life Science and Technology, Tongji University, 1239 Siping Road, Shanghai 200092, P.R. China
| | - Luming Zhuang
- Institute of Intervention Vessel, Shanghai 10th People's Hospital, Shanghai Key Laboratory of Signaling and Disease Research, School of Life Science and Technology, Tongji University, 1239 Siping Road, Shanghai 200092, China
| | - Lei Xue
- Institute of Intervention Vessel, Shanghai 10th People's Hospital, Shanghai Key Laboratory of Signaling and Disease Research, School of Life Science and Technology, Tongji University, 1239 Siping Road, Shanghai 200092, China
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31
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Caous R, Pascal A, Romé P, Richard-Parpaillon L, Karess R, Giet R. Spindle assembly checkpoint inactivation fails to suppress neuroblast tumour formation in aurA mutant Drosophila. Nat Commun 2015; 6:8879. [PMID: 26568519 PMCID: PMC4660220 DOI: 10.1038/ncomms9879] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2015] [Accepted: 10/10/2015] [Indexed: 12/18/2022] Open
Abstract
Tissue homeostasis requires accurate control of cell proliferation, differentiation and chromosome segregation. Drosophila sas-4 and aurA mutants present brain tumours with extra neuroblasts (NBs), defective mitotic spindle assembly and delayed mitosis due to activation of the spindle assembly checkpoint (SAC). Here we inactivate the SAC in aurA and sas-4 mutants to determine whether the generation of aneuploidy compromises NB proliferation. Inactivation of the SAC in the sas-4 mutant impairs NB proliferation and disrupts euploidy. By contrast, disrupting the SAC in the aurA mutant does not prevent NB amplification, tumour formation or chromosome segregation. The monitoring of Mad2 and cyclin B dynamics in live aurA NBs reveals that SAC satisfaction is not coupled to cyclin B degradation. Thus, the NBs of aurA mutants present delayed mitosis, with accurate chromosome segregation occurring in a SAC-independent manner. We report here the existence of an Aurora A-dependent mechanism promoting efficient, timed cyclin B degradation.
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Affiliation(s)
- Renaud Caous
- Institut de Génétique et Développement de Rennes-Université de Rennes I-CNRS- UMR 6290, 2 avenue du Pr Léon Bernard, 35043 Rennes, France
| | - Aude Pascal
- Institut de Génétique et Développement de Rennes-Université de Rennes I-CNRS- UMR 6290, 2 avenue du Pr Léon Bernard, 35043 Rennes, France
| | - Pierre Romé
- Institut de Génétique et Développement de Rennes-Université de Rennes I-CNRS- UMR 6290, 2 avenue du Pr Léon Bernard, 35043 Rennes, France
| | - Laurent Richard-Parpaillon
- Institut de Génétique et Développement de Rennes-Université de Rennes I-CNRS- UMR 6290, 2 avenue du Pr Léon Bernard, 35043 Rennes, France
| | - Roger Karess
- Institut Jacques Monod-Université Paris Diderot-Paris 7, 15 rue Hélène Brion, 75205 Paris, France
| | - Régis Giet
- Institut de Génétique et Développement de Rennes-Université de Rennes I-CNRS- UMR 6290, 2 avenue du Pr Léon Bernard, 35043 Rennes, France
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32
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von Schubert C, Cubizolles F, Bracher JM, Sliedrecht T, Kops GJPL, Nigg EA. Plk1 and Mps1 Cooperatively Regulate the Spindle Assembly Checkpoint in Human Cells. Cell Rep 2015; 12:66-78. [PMID: 26119734 DOI: 10.1016/j.celrep.2015.06.007] [Citation(s) in RCA: 81] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2015] [Revised: 05/14/2015] [Accepted: 06/01/2015] [Indexed: 01/13/2023] Open
Abstract
Equal mitotic chromosome segregation is critical for genome integrity and is monitored by the spindle assembly checkpoint (SAC). We have previously shown that the consensus phosphorylation motif of the essential SAC kinase Monopolar spindle 1 (Mps1) is very similar to that of Polo-like kinase 1 (Plk1). This prompted us to ask whether human Plk1 cooperates with Mps1 in SAC signaling. Here, we demonstrate that Plk1 promotes checkpoint signaling at kinetochores through the phosphorylation of at least two Mps1 substrates, including KNL-1 and Mps1 itself. As a result, Plk1 activity enhances Mps1 catalytic activity as well as the recruitment of the SAC components Mad1:C-Mad2 and Bub3:BubR1 to kinetochores. We conclude that Plk1 strengthens the robustness of SAC establishment at the onset of mitosis and supports SAC maintenance during prolonged mitotic arrest.
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Affiliation(s)
- Conrad von Schubert
- Biozentrum, University of Basel, Klingelbergstrasse 50/70, 4056 Basel, Switzerland
| | - Fabien Cubizolles
- Biozentrum, University of Basel, Klingelbergstrasse 50/70, 4056 Basel, Switzerland
| | - Jasmine M Bracher
- Biozentrum, University of Basel, Klingelbergstrasse 50/70, 4056 Basel, Switzerland
| | - Tale Sliedrecht
- Molecular Cancer Research, University Medical Center Utrecht, 3584 CG, Utrecht, the Netherlands; Center for Molecular Medicine, University Medical Center Utrecht, 3584 CG, Utrecht, the Netherlands; Cancer Genomics Netherlands, University Medical Center Utrecht, 3584 CG, Utrecht, the Netherlands
| | - Geert J P L Kops
- Molecular Cancer Research, University Medical Center Utrecht, 3584 CG, Utrecht, the Netherlands; Center for Molecular Medicine, University Medical Center Utrecht, 3584 CG, Utrecht, the Netherlands; Cancer Genomics Netherlands, University Medical Center Utrecht, 3584 CG, Utrecht, the Netherlands
| | - Erich A Nigg
- Biozentrum, University of Basel, Klingelbergstrasse 50/70, 4056 Basel, Switzerland.
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33
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Kapanidou M, Lee S, Bolanos-Garcia VM. BubR1 kinase: protection against aneuploidy and premature aging. Trends Mol Med 2015; 21:364-72. [DOI: 10.1016/j.molmed.2015.04.003] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2014] [Revised: 03/23/2015] [Accepted: 04/07/2015] [Indexed: 11/28/2022]
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34
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Savoian MS, Glover DM. Differing requirements for Augmin in male meiotic and mitotic spindle formation in Drosophila. Open Biol 2015; 4:140047. [PMID: 24829288 PMCID: PMC4042853 DOI: 10.1098/rsob.140047] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Animal cells divide using a microtubule-based, bipolar spindle. Both somatic, mitotic cells and sperm-producing male meiotic spermatocytes use centrosome-dependent and acentrosomal spindle-forming mechanisms. Here, we characterize the largely undefined, centrosome-independent spindle formation pathway used during male meiosis. Our live and fixed cell analyses of Drosophila spermatocytes reveal that acentrosomal microtubules are nucleated at kinetochores and in the vicinity of chromatin and that together these assemble into functional spindles. Mutational studies indicate that γ-tubulin and its extra-centrosomal targeting complex, Augmin, are vital for this process. In addition, Augmin facilitates efficient spindle assembly in the presence of centrosomes. In contrast to the pronounced recruitment of Augmin on spindles in other cell types, the complex is absent from those of spermatocytes but does accumulate on kinetochores. Polo kinase facilitates this kinetochore recruitment while inhibiting Augmin's spindle association, and this in turn dictates γ-tubulin distribution and spindle density. Polo's negative regulation of Augmin in male meiosis contrasts with its requirement in loading Augmin along mitotic spindles in somatic Drosophila cells. Together our data identify a novel mechanism of acentrosomal spindle formation in spermatocytes and reveal its divergence from that used in mitotic cells.
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Affiliation(s)
- Matthew S Savoian
- Department of Genetics, University of Cambridge, Downing Site, Cambridge CB2 3EH, UK
| | - David M Glover
- Department of Genetics, University of Cambridge, Downing Site, Cambridge CB2 3EH, UK
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35
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Bimodal activation of BubR1 by Bub3 sustains mitotic checkpoint signaling. Proc Natl Acad Sci U S A 2014; 111:E4185-93. [PMID: 25246557 DOI: 10.1073/pnas.1416277111] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
The mitotic checkpoint (also known as the spindle assembly checkpoint) prevents premature anaphase onset through generation of an inhibitor of the E3 ubiquitin ligase APC/C, whose ubiquitination of cyclin B and securin targets them for degradation. Combining in vitro reconstitution and cell-based assays, we now identify dual mechanisms through which Bub3 promotes mitotic checkpoint signaling. Bub3 enhances signaling at unattached kinetochores not only by facilitating binding of BubR1 but also by enhancing Cdc20 recruitment to kinetochores mediated by BubR1's internal Cdc20 binding site. Downstream of kinetochore-produced complexes, Bub3 promotes binding of BubR1's conserved, amino terminal Cdc20 binding domain to a site in Cdc20 that becomes exposed by initial Mad2 binding. This latter Bub3-stimulated event generates the final mitotic checkpoint complex of Bub3-BubR1-Cdc20 that selectively inhibits ubiquitination of securin and cyclin B by APC/C(Cdc20). Thus, Bub3 promotes two distinct BubR1-Cdc20 interactions, involving each of the two Cdc20 binding sites of BubR1 and acting at unattached kinetochores or cytoplasmically, respectively, to facilitate production of the mitotic checkpoint inhibitor.
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Ling Y, Zhang X, Bai Y, Li P, Wei C, Song T, Zheng Z, Guan K, Zhang Y, Zhang B, Liu X, Ma RZ, Cao C, Zhong H, Xu Q. Overexpression of Mps1 in colon cancer cells attenuates the spindle assembly checkpoint and increases aneuploidy. Biochem Biophys Res Commun 2014; 450:1690-5. [PMID: 25063032 DOI: 10.1016/j.bbrc.2014.07.071] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2014] [Accepted: 07/15/2014] [Indexed: 12/25/2022]
Abstract
The spindle assembly checkpoint kinase Mps1 is highly expressed in several types of cancers, but its cellular involvement in tumorigenesis is less defined. Herein, we confirm that Mps1 is overexpressed in colon cancer tissues. Further, we find that forced expression of Mps1 in the colon cancer cell line SW480 enables cells to become resistant to both Mps1 inhibition-induced checkpoint depletion and cell death. Overexpression of Mps1 also increases genome instability in tumor cells owing to a weakened spindle assembly checkpoint. Collectively, our findings suggest that high levels of Mps1 contribute to tumorigenesis by attenuating the spindle assembly checkpoint.
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Affiliation(s)
- Youguo Ling
- Department of Life Science, Anhui University, Hefei, China; Beijing Institute of Biotechnology, Beijing, China
| | - Xiaojuan Zhang
- Center for Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China
| | - Yuanyuan Bai
- Beijing Institute of Biotechnology, Beijing, China
| | - Ping Li
- Beijing Institute of Biotechnology, Beijing, China
| | - Congwen Wei
- Beijing Institute of Biotechnology, Beijing, China
| | - Ting Song
- Beijing Institute of Biotechnology, Beijing, China
| | - Zirui Zheng
- Beijing Institute of Biotechnology, Beijing, China
| | - Kai Guan
- Beijing Institute of Biotechnology, Beijing, China
| | | | - Buchang Zhang
- Department of Life Science, Anhui University, Hefei, China
| | - Xuedong Liu
- University of Colorado at Boulder, Boulder, CO, USA
| | - Runlin Z Ma
- Center for Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China
| | - Cheng Cao
- Beijing Institute of Biotechnology, Beijing, China.
| | - Hui Zhong
- Beijing Institute of Biotechnology, Beijing, China.
| | - Quanbin Xu
- Beijing Institute of Biotechnology, Beijing, China.
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Catch and release: how do kinetochores hook the right microtubules during mitosis? Trends Genet 2014; 30:150-9. [PMID: 24631209 DOI: 10.1016/j.tig.2014.02.004] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2013] [Revised: 02/13/2014] [Accepted: 02/14/2014] [Indexed: 11/22/2022]
Abstract
Sport fishermen keep tension on their lines to prevent hooked fish from releasing. A molecular version of this angler's trick, operating at kinetochores, ensures accuracy during mitosis: the mitotic spindle attaches randomly to chromosomes and then correctly bioriented attachments are stabilized due to the tension exerted on them by opposing microtubules. Incorrect attachments, which lack tension, are unstable and release quickly, allowing another chance for biorientation. Stabilization of molecular interactions by tension also occurs in other physiological contexts, such as cell adhesion, motility, hemostasis, and tissue morphogenesis. Here, we review models for the stabilization of kinetochore attachments with an eye toward emerging models for other force-activated systems. Although attention in the mitosis field has focused mainly on one kinase-based mechanism, multiple mechanisms may act together to stabilize properly bioriented kinetochores and some principles governing other tension-sensitive systems may also apply to kinetochores.
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Feijão T, Afonso O, Maia AF, Sunkel CE. Stability of kinetochore-microtubule attachment and the role of different KMN network components in Drosophila. Cytoskeleton (Hoboken) 2013; 70:661-75. [PMID: 23959943 DOI: 10.1002/cm.21131] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2013] [Revised: 08/02/2013] [Accepted: 08/06/2013] [Indexed: 11/11/2022]
Abstract
Kinetochores bind spindle microtubules and also act as signaling centers that monitor this interaction. Defects in kinetochore assembly lead to chromosome missegregation and aneuploidy. The interaction between microtubules and chromosomes involves a conserved super-complex of proteins, known as the KNL1Mis12Ndc80 (KMN) network, composed by the KNL1 (Spc105), Mis12, and Ndc80 complexes. Previous studies indicate that all components of the network are required for kinetochore-microtubule attachment and all play relevant functions in chromosome congression, biorientation, and segregation. Here, we report a comparative study addressing the role of the different KMN components using dsRNA and in vivo fluorescence microscopy in Drosophila S2 cells allowing us to suggest that different KMN network components might perform different roles in chromosome segregation and the mitotic checkpoint signaling. Depletion of different components results in mostly lateral kinetochore-microtubule attachments that are relatively stable on depletion of Mis12 or Ndc80 but very unstable after Spc105 depletion. In vivo analysis on depletion of Mis12, Ndc80, and to some extent Spc105, shows that lateral kinetochore-microtubule interactions are still functional allowing poleward kinetochore movement. We also find that different KMN network components affect differently the localization of spindle assembly checkpoint (SAC) proteins at kinetochores. Depletion of Ndc80 and Spc105 abolishes the mitotic checkpoint, whereas depletion of Mis12 causes a delay in mitotic progression. Taken together, our results suggest that Mis12 and Ndc80 complexes help to properly orient microtubule attachment, whereas Spc105 plays a predominant role in the kinetochore-microtubule attachment as well as in the poleward movement of chromosomes, SAC response, and cell viability.
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Affiliation(s)
- Tália Feijão
- IBMC, Instituto de Biologia Molecular e Celular, Molecular Genetics, Universidade do Porto, Rua do Campo Alegre 823, 4150-180, Porto, Portugal
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Conde C, Osswald M, Sunkel CE. All together now: Polo joins the kinase network controlling the spindle assembly checkpoint in Drosophila. Fly (Austin) 2013; 7:224-8. [PMID: 23989224 DOI: 10.4161/fly.26231] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Maintenance of genomic stability during eukaryotic cell division relies on the Spindle Assembly Checkpoint (SAC), which has evolved as a surveillance mechanism that monitors kinetochore-microtubule attachment and prevents APC/C-mediated mitotic exit until all chromosomes are properly attached to the mitotic spindle. Reversible protein phosphorylation has long been accredited as a regulatory mechanism of the SAC. Nevertheless, knowledge of how several mitotic kinases act in concert within the signaling pathway to orchestrate SAC function is still emerging. In a recent study, we undertook a comprehensive dissection of the hierarchical framework controlling SAC function in Drosophila cells. We found that Polo lies at the top of the SAC pathway promoting the efficient recruitment of Mps1 to unattached kinetochores. This renders Mps1 fully active to control BubR1 phosphorylation that generates the 3F3/2 phosphoepitope at tensionless kinetochores. We have proposed that Polo is required for SAC function and that the molecular outcome of Mps1-dependent 3F3/2 formation is to promote the association of Cdc20 with BubR1 allowing proper kinetochore recruitment of Cdc20 and efficient assembly of the Mitotic Checkpoint Complex (MCC) required for a sustained SAC response.
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Affiliation(s)
- Carlos Conde
- IBMC; Instituto de Biologia Molecular e Celular; Universidade do Porto; Porto, Portugal
| | - Mariana Osswald
- IBMC; Instituto de Biologia Molecular e Celular; Universidade do Porto; Porto, Portugal
| | - Claudio E Sunkel
- IBMC; Instituto de Biologia Molecular e Celular; Universidade do Porto; Porto, Portugal; ICBAS; Department of Molecular Biology; Instituto de Ciências Biomédicas Abel Salazar; Universidade do Porto; Porto, Portugal
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