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GİRGİN SM, ÇAYDAŞI AKOCA. Bud14 function is crucial for spindle pole body size maintenance. Turk J Biol 2024; 48:267-278. [PMID: 39296336 PMCID: PMC11407341 DOI: 10.55730/1300-0152.2702] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2024] [Revised: 08/23/2024] [Accepted: 08/05/2024] [Indexed: 09/21/2024] Open
Abstract
Background/aim Spindle pole bodies (SPB), the functional equivalent of centrosomes in yeast, duplicate through generation of a new SPB next to the old one. However, SPBs are dynamic structures that can grow and exchange, and mechanisms that regulate SPB size remain largely unknown. This study aims to elucidate the role of Bud14 in SPB size maintenance in Saccharomyces cerevisiae. Materials and methods We employed quantitative fluorescence microscopy to assess the relative and absolute amounts of SPB structural proteins at SPBs of wildtype cells and in cells lacking BUD14 (bud14Δ). Quantifications were performed using asynchronous cell cultures, as well as cultures synchronously progressing through the cell cycle and upon different cell cycle arrests. We also utilized mutants that allow the separation of Bud14 functions. Results Our results indicate that higher levels of SPB inner, outer, and central plaque proteins are present at the SPBs of bud14Δ cells compared to wildtype cells during anaphase, as well as during nocodazole-induced M-phase arrest. However, during α-factor mediated G1 arrest, inner and outer plaque proteins responded differently to the absence of BUD14. A Bud14 mutant that cannot interact with the Protein Phosphatase 1 (Glc7) phenocopied bud14Δ in terms of SPB-bound levels of the inner plaque protein Spc110, whereas disruption of Bud14-Kel1-Kel2 complex did not alter Spc110 levels at SPBs. In cells synchronously released from α-factor arrest, lack of Bud14-Glc7 caused increase of Spc110 at the SPBs at early stages of the cell cycle. Conclusion We identified Bud14 as a critical protein for SPB size maintenance. The interaction of Bud14 with Glc7, but not with the Kelch proteins, is indispensable for restricting levels of Spc110 incorporated into the SPBs.
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Affiliation(s)
- Sevilay Münire GİRGİN
- Department of Molecular Biology and Genetics, Collage of Sciences, Koç University, İstanbul,
Turkiye
| | - Ayşe KOCA ÇAYDAŞI
- Department of Molecular Biology and Genetics, Collage of Sciences, Koç University, İstanbul,
Turkiye
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2
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The N-Terminal Domain of Bfa1 Coordinates Mitotic Exit Independent of GAP Activity in Saccharomyces cerevisiae. Cells 2022; 11:cells11142179. [PMID: 35883622 PMCID: PMC9316867 DOI: 10.3390/cells11142179] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2022] [Revised: 07/06/2022] [Accepted: 07/07/2022] [Indexed: 12/10/2022] Open
Abstract
The spindle position checkpoint (SPOC) of budding yeast delays mitotic exit in response to misaligned spindles to ensure cell survival and the maintenance of genomic stability. The GTPase-activating protein (GAP) complex Bfa1–Bub2, a key SPOC component, inhibits the GTPase Tem1 to induce mitotic arrest in response to DNA and spindle damage, as well as spindle misorientation. However, previous results strongly suggest that Bfa1 exerts a GAP-independent function in blocking mitotic exit in response to misaligned spindles. Thus, the molecular mechanism by which Bfa1 controls mitotic exit in response to misaligned spindles remains unclear. Here, we observed that overexpression of the N-terminal domain of Bfa1 (Bfa1-D16), which lacks GAP activity and cannot localize to the spindle pole body (SPB), induced cell cycle arrest along with hyper-elongation of astral microtubules (aMTs) as Bfa1 overexpression in Δbub2. We found that Δbub2 cells overexpressing Bfa1 or Bfa1-D16 inhibited activation of Mob1, which is responsible for mitotic exit. In anaphase-arrested cells, Bfa1-D16 overexpression inhibited Tem1 binding to the SPB as well as Bfa1 overexpression. Additionally, endogenous levels of Bfa1-D16 showed minor SPOC activity that was not regulated by Kin4. These results suggested that Bfa1-D16 may block mitotic exit through inhibiting Tem1 activity outside of SPBs. Alternatively, Bfa1-D16 dispersed out of SPBs may block Tem1 binding to SPBs by physically interacting with Tem1 as previously reported. Moreover, we observed hyper-elongated aMTs in tem1-3, cdc15-2, and dbf2-2 mutants that induce anaphase arrest and cannot undergo mitotic exit at restrictive temperatures, suggesting that aMT dynamics are closely related to the regulation of mitotic exit. Altogether, these observations suggest that Bfa1 can control the SPOC independent of its GAP activity and SPB localization.
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3
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Strini EJ, Bertolino LT, San Martin JAB, Souza HAO, Pessotti F, Pinoti VF, Ferreira PB, De Paoli HC, Lubini G, Del-Bem LE, Quiapim AC, Mondin M, Araujo APU, Eloy NB, Barberis M, Goldman MHS. Stigma/Style Cell-Cycle Inhibitor 1, a Regulator of Cell Proliferation, Interacts With a Specific 14-3-3 Protein and Is Degraded During Cell Division. FRONTIERS IN PLANT SCIENCE 2022; 13:857745. [PMID: 35444668 PMCID: PMC9013909 DOI: 10.3389/fpls.2022.857745] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/19/2022] [Accepted: 03/14/2022] [Indexed: 06/14/2023]
Abstract
The final shape and size of plant organs are determined by a network of genes that modulate cell proliferation and expansion. Among those, SCI1 (Stigma/style Cell-cycle Inhibitor 1) functions by inhibiting cell proliferation during pistil development. Alterations in SCI1 expression levels can lead to remarkable stigma/style size changes. Recently, we demonstrated that SCI1 starts to be expressed at the specification of the Nicotiana tabacum floral meristem and is expressed at all floral meristematic cells. To elucidate how SCI1 regulates cell proliferation, we screened a stigma/style cDNA library through the yeast two-hybrid (Y2H) system, using SCI1 as bait. Among the interaction partners, we identified the 14-3-3D protein of the Non-Epsilon group. The interaction between SCI1 and 14-3-3D was confirmed by pulldown and co-immunoprecipitation experiments. 14-3-3D forms homo- and heterodimers in the cytoplasm of plant cells and interacts with SCI1 in the nucleus, as demonstrated by Bimolecular Fluorescence Complementation (BiFC). Analyses of SCI1-GFP fluorescence through the cell-cycle progression revealed its presence in the nucleoli during interphase and prophase. At metaphase, SCI1-GFP fluorescence faded and was no longer detected at anaphase, reappearing at telophase. Upon treatment with the 26S proteasome inhibitor MG132, SCI1-GFP was stabilized during cell division. Site-directed mutagenesis of seven serines into alanines in the predicted 14-3-3 binding sites on the SCI1 sequence prevented its degradation during mitosis. Our results demonstrate that SCI1 degradation at the beginning of metaphase is dependent on the phosphorylation of serine residues and on the action of the 26S proteasome. We concluded that SCI1 stability/degradation is cell-cycle regulated, consistent with its role in fine-tuning cell proliferation.
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Affiliation(s)
- Edward J. Strini
- Departamento de Biologia, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, University of São Paulo, Ribeirão Preto, Brazil
- PPG-Genética, Faculdade de Medicina de Ribeirão Preto, University of São Paulo, Ribeirão Preto, Brazil
| | - Lígia T. Bertolino
- Departamento de Biologia, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, University of São Paulo, Ribeirão Preto, Brazil
- PPG-Genética, Faculdade de Medicina de Ribeirão Preto, University of São Paulo, Ribeirão Preto, Brazil
| | - Juca A. B. San Martin
- Departamento de Biologia, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, University of São Paulo, Ribeirão Preto, Brazil
| | - Hebréia A. O. Souza
- Departamento de Biologia, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, University of São Paulo, Ribeirão Preto, Brazil
| | - Francine Pessotti
- Departamento de Biologia, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, University of São Paulo, Ribeirão Preto, Brazil
- PPG-Genética, Faculdade de Medicina de Ribeirão Preto, University of São Paulo, Ribeirão Preto, Brazil
| | - Vitor F. Pinoti
- Departamento de Biologia, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, University of São Paulo, Ribeirão Preto, Brazil
- PPG-Genética, Faculdade de Medicina de Ribeirão Preto, University of São Paulo, Ribeirão Preto, Brazil
| | - Pedro B. Ferreira
- Departamento de Biologia, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, University of São Paulo, Ribeirão Preto, Brazil
- PPG-Genética, Faculdade de Medicina de Ribeirão Preto, University of São Paulo, Ribeirão Preto, Brazil
| | - Henrique C. De Paoli
- Departamento de Biologia, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, University of São Paulo, Ribeirão Preto, Brazil
- PPG-Genética, Faculdade de Medicina de Ribeirão Preto, University of São Paulo, Ribeirão Preto, Brazil
| | - Greice Lubini
- Departamento de Biologia, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, University of São Paulo, Ribeirão Preto, Brazil
- PPG-Genética, Faculdade de Medicina de Ribeirão Preto, University of São Paulo, Ribeirão Preto, Brazil
| | - Luiz-Eduardo Del-Bem
- Departamento de Botânica, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Andréa C. Quiapim
- Departamento de Biologia, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, University of São Paulo, Ribeirão Preto, Brazil
| | - Mateus Mondin
- Departamento de Genética, Escola Superior de Agricultura Luiz de Queiroz, University of São Paulo, Piracicaba, Brazil
| | - Ana Paula U. Araujo
- São Carlos Institute of Physics, University of São Paulo, São Carlos, Brazil
| | - Nubia B. Eloy
- Departamento de Ciências Biológicas, Escola Superior de Agricultura Luiz de Queiroz, University of São Paulo, Piracicaba, Brazil
| | - Matteo Barberis
- Systems Biology, School of Biosciences and Medicine, Faculty of Health and Medical Sciences, University of Surrey, Guildford, United Kingdom
- Centre for Mathematical and Computational Biology, CMCB, University of Surrey, Guildford, United Kingdom
- Synthetic Systems Biology and Nuclear Organization, Swammerdam Institute for Life Sciences, University of Amsterdam, Amsterdam, Netherlands
| | - Maria Helena S. Goldman
- Departamento de Biologia, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, University of São Paulo, Ribeirão Preto, Brazil
- PPG-Genética, Faculdade de Medicina de Ribeirão Preto, University of São Paulo, Ribeirão Preto, Brazil
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4
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Howell RSM, Klemm C, Thorpe PH, Csikász-Nagy A. Unifying the mechanism of mitotic exit control in a spatiotemporal logical model. PLoS Biol 2020; 18:e3000917. [PMID: 33180788 PMCID: PMC7685450 DOI: 10.1371/journal.pbio.3000917] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2020] [Revised: 11/24/2020] [Accepted: 10/09/2020] [Indexed: 11/18/2022] Open
Abstract
The transition from mitosis into the first gap phase of the cell cycle in budding yeast is controlled by the Mitotic Exit Network (MEN). The network interprets spatiotemporal cues about the progression of mitosis and ensures that release of Cdc14 phosphatase occurs only after completion of key mitotic events. The MEN has been studied intensively; however, a unified understanding of how localisation and protein activity function together as a system is lacking. In this paper, we present a compartmental, logical model of the MEN that is capable of representing spatial aspects of regulation in parallel to control of enzymatic activity. We show that our model is capable of correctly predicting the phenotype of the majority of mutants we tested, including mutants that cause proteins to mislocalise. We use a continuous time implementation of the model to demonstrate that Cdc14 Early Anaphase Release (FEAR) ensures robust timing of anaphase, and we verify our findings in living cells. Furthermore, we show that our model can represent measured cell-cell variation in Spindle Position Checkpoint (SPoC) mutants. This work suggests a general approach to incorporate spatial effects into logical models. We anticipate that the model itself will be an important resource to experimental researchers, providing a rigorous platform to test hypotheses about regulation of mitotic exit.
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Affiliation(s)
- Rowan S M Howell
- The Francis Crick Institute, London, United Kingdom.,Randall Centre for Cell and Molecular Biophysics, King's College London, London, United Kingdom
| | - Cinzia Klemm
- School of Biological and Chemical Sciences, Queen Mary University, London, United Kingdom
| | - Peter H Thorpe
- School of Biological and Chemical Sciences, Queen Mary University, London, United Kingdom
| | - Attila Csikász-Nagy
- Randall Centre for Cell and Molecular Biophysics, King's College London, London, United Kingdom.,Faculty of Information Technology and Bionics, Pázmány Péter Catholic University, Budapest, Hungary
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5
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Jiménez J, Queralt E, Posas F, de Nadal E. The regulation of Net1/Cdc14 by the Hog1 MAPK upon osmostress unravels a new mechanism regulating mitosis. Cell Cycle 2020; 19:2105-2118. [PMID: 32794416 PMCID: PMC7513861 DOI: 10.1080/15384101.2020.1804222] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
During evolution, cells have developed a plethora of mechanisms to optimize survival in a changing and unpredictable environment. In this regard, they have evolved networks that include environmental sensors, signaling transduction molecules and response mechanisms. Hog1 (yeast) and p38 (mammals) stress-activated protein kinases (SAPKs) are activated upon stress and they drive a full collection of cell adaptive responses aimed to maximize survival. SAPKs are extensively used to learn about the mechanisms through which cells adapt to changing environments. In addition to regulating gene expression and metabolism, SAPKs control cell cycle progression. In this review, we will discuss the latest findings related to the SAPK-driven regulation of mitosis upon osmostress in yeast.
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Affiliation(s)
- Javier Jiménez
- Departament De Ciències Experimentals I De La Salut, Universitat Pompeu Fabra (UPF) , Barcelona, Spain.,Department of Ciències Bàsiques, Facultat De Medicina I Ciències De La Salut, Universitat Internacional De Catalunya , Barcelona, Spain
| | - Ethel Queralt
- Cell Cycle Group, Institut d'Investigacions Biomèdica De Bellvitge (IDIBELL), L'Hospitalet De Llobregat , Barcelona, Spain
| | - Francesc Posas
- Departament De Ciències Experimentals I De La Salut, Universitat Pompeu Fabra (UPF) , Barcelona, Spain.,Institute for Research in Biomedicine (IRB Barcelona), the Barcelona Institute of Science and Technology , 08028 Barcelona, Spain
| | - Eulàlia de Nadal
- Departament De Ciències Experimentals I De La Salut, Universitat Pompeu Fabra (UPF) , Barcelona, Spain.,Institute for Research in Biomedicine (IRB Barcelona), the Barcelona Institute of Science and Technology , 08028 Barcelona, Spain
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6
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Skruzny M, Pohl E, Gnoth S, Malengo G, Sourjik V. The protein architecture of the endocytic coat analyzed by FRET microscopy. Mol Syst Biol 2020; 16:e9009. [PMID: 32400111 PMCID: PMC7218409 DOI: 10.15252/msb.20199009] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2019] [Revised: 04/02/2020] [Accepted: 04/03/2020] [Indexed: 12/16/2022] Open
Abstract
Endocytosis is a fundamental cellular trafficking pathway, which requires an organized assembly of the multiprotein endocytic coat to pull the plasma membrane into the cell. Although the protein composition of the endocytic coat is known, its functional architecture is not well understood. Here, we determine the nanoscale organization of the endocytic coat by FRET microscopy in yeast Saccharomyces cerevisiae. We assessed pairwise proximities of 18 conserved coat-associated proteins and used clathrin subunits and protein truncations as molecular rulers to obtain a high-resolution protein map of the coat. Furthermore, we followed rearrangements of coat proteins during membrane invagination and their binding dynamics at the endocytic site. We show that the endocytic coat proteins are not confined inside the clathrin lattice, but form distinct functional layers above and below the lattice. Importantly, key endocytic proteins transverse the clathrin lattice deeply into the cytoplasm connecting thus the membrane and cytoplasmic parts of the coat. We propose that this design enables an efficient and regulated function of the endocytic coat during endocytic vesicle formation.
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Affiliation(s)
- Michal Skruzny
- Department of Systems and Synthetic MicrobiologyMax Planck Institute for Terrestrial MicrobiologyMarburgGermany
- LOEWE Center for Synthetic Microbiology (SYNMIKRO)MarburgGermany
| | - Emma Pohl
- Department of Systems and Synthetic MicrobiologyMax Planck Institute for Terrestrial MicrobiologyMarburgGermany
- LOEWE Center for Synthetic Microbiology (SYNMIKRO)MarburgGermany
| | - Sandina Gnoth
- Department of Systems and Synthetic MicrobiologyMax Planck Institute for Terrestrial MicrobiologyMarburgGermany
- LOEWE Center for Synthetic Microbiology (SYNMIKRO)MarburgGermany
| | - Gabriele Malengo
- Department of Systems and Synthetic MicrobiologyMax Planck Institute for Terrestrial MicrobiologyMarburgGermany
- LOEWE Center for Synthetic Microbiology (SYNMIKRO)MarburgGermany
| | - Victor Sourjik
- Department of Systems and Synthetic MicrobiologyMax Planck Institute for Terrestrial MicrobiologyMarburgGermany
- LOEWE Center for Synthetic Microbiology (SYNMIKRO)MarburgGermany
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7
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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: 16] [Impact Index Per Article: 4.0] [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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8
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Skruzny M, Pohl E, Abella M. FRET Microscopy in Yeast. BIOSENSORS 2019; 9:E122. [PMID: 31614546 PMCID: PMC6956097 DOI: 10.3390/bios9040122] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/30/2019] [Revised: 09/19/2019] [Accepted: 09/30/2019] [Indexed: 02/06/2023]
Abstract
Förster resonance energy transfer (FRET) microscopy is a powerful fluorescence microscopy method to study the nanoscale organization of multiprotein assemblies in vivo. Moreover, many biochemical and biophysical processes can be followed by employing sophisticated FRET biosensors directly in living cells. Here, we summarize existing FRET experiments and biosensors applied in yeasts Saccharomyces cerevisiae and Schizosaccharomyces pombe, two important models of fundamental biomedical research and efficient platforms for analyses of bioactive molecules. We aim to provide a practical guide on suitable FRET techniques, fluorescent proteins, and experimental setups available for successful FRET experiments in yeasts.
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Affiliation(s)
- Michal Skruzny
- Department of Systems and Synthetic Microbiology, Max Planck Institute for Terrestrial Microbiology, 35043 Marburg, Germany.
- LOEWE Center for Synthetic Microbiology (SYNMIKRO), 35043 Marburg, Germany.
| | - Emma Pohl
- Department of Systems and Synthetic Microbiology, Max Planck Institute for Terrestrial Microbiology, 35043 Marburg, Germany
- LOEWE Center for Synthetic Microbiology (SYNMIKRO), 35043 Marburg, Germany
| | - Marc Abella
- Department of Systems and Synthetic Microbiology, Max Planck Institute for Terrestrial Microbiology, 35043 Marburg, Germany
- LOEWE Center for Synthetic Microbiology (SYNMIKRO), 35043 Marburg, Germany
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9
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Howell RSM, Csikász-Nagy A, Thorpe PH. Synthetic Physical Interactions with the Yeast Centrosome. G3 (BETHESDA, MD.) 2019; 9:2183-2194. [PMID: 31076383 PMCID: PMC6643875 DOI: 10.1534/g3.119.400117] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/21/2019] [Accepted: 05/02/2019] [Indexed: 12/30/2022]
Abstract
The yeast centrosome or Spindle Pole Body (SPB) is an organelle situated in the nuclear membrane, where it nucleates spindle microtubules and acts as a signaling hub. Various studies have explored the effects of forcing individual proteins to interact with the yeast SPB, however no systematic study has been performed. We used synthetic physical interactions to detect proteins that inhibit growth when forced to associate with the SPB. We found the SPB to be especially sensitive to relocalization, necessitating a novel data analysis approach. This novel analysis of SPI screening data shows that regions of the cell are locally more sensitive to forced relocalization than previously thought. Furthermore, we found a set of associations that result in elevated SPB number and, in some cases, multi-polar spindles. Since hyper-proliferation of centrosomes is a hallmark of cancer cells, these associations point the way for the use of yeast models in the study of spindle formation and chromosome segregation in cancer.
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Affiliation(s)
- Rowan S M Howell
- The Francis Crick Institute, London, NW1 1AT UK
- Randall Division of Cell and Molecular Biophysics, King's College, London, SE1 1UL UK
| | - Attila Csikász-Nagy
- Randall Division of Cell and Molecular Biophysics, King's College, London, SE1 1UL UK
- Faculty of Information Technology and Bionics, Pázmány Péter Catholic University, Budapest, 1083 Hungary
| | - Peter H Thorpe
- School of Biological and Chemical Sciences, Queen Mary University, London, E1 4NS UK
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10
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Budding Yeast BFA1 Has Multiple Positive Roles in Directing Late Mitotic Events. G3-GENES GENOMES GENETICS 2018; 8:3397-3410. [PMID: 30166350 PMCID: PMC6222586 DOI: 10.1534/g3.118.200672] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
The proper regulation of cell cycle transitions is paramount to the maintenance of cellular genome integrity. In Saccharomyces cerevisiae, the mitotic exit network (MEN) is a Ras-like signaling cascade that effects the transition from M phase to G1 during the cell division cycle in budding yeast. MEN activation is tightly regulated. It occurs during anaphase and is coupled to mitotic spindle position by the spindle position checkpoint (SPoC). Bfa1 is a key component of the SPoC and functions as part of a two-component GAP complex along with Bub2 The GAP activity of Bfa1-Bub2 keeps the MEN GTPase Tem1 inactive in cells with mispositioned spindles, thereby preventing inappropriate mitotic exit and preserving genome integrity. Interestingly, a GAP-independent role for Bfa1 in mitotic exit regulation has been previously identified. However the nature of this Bub2-independent role and its biological significance are not understood. Here we show that Bfa1 also activates the MEN by promoting the localization of Tem1 primarily to the daughter spindle pole body (dSPB). We demonstrate that the overexpression of BFA1 is lethal due to defects in Tem1 localization, which is required for its activity. In addition, our studies demonstrate a Tem1-independent role for Bfa1 in promoting proper cytokinesis. Cells lacking TEM1, in which the essential mitotic exit function is bypassed, exhibit cytokinesis defects. These defects are suppressed by the overexpression of BFA1 We conclude that Bfa1 functions to both inhibit and activate late mitotic events.
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11
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Botchkarev VV, Haber JE. Functions and regulation of the Polo-like kinase Cdc5 in the absence and presence of DNA damage. Curr Genet 2018; 64:87-96. [PMID: 28770345 PMCID: PMC6249032 DOI: 10.1007/s00294-017-0727-2] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2017] [Revised: 07/24/2017] [Accepted: 07/26/2017] [Indexed: 12/20/2022]
Abstract
Polo-like kinases are essential cell cycle regulators that are conserved from yeast to humans. Unlike higher eukaryotes, who express multiple Polo-like kinase family members that perform many important functions, budding yeast express only a single Polo-like kinase, Cdc5, which is the homolog of mammalian cell cycle master regulator Polo-like kinase 1. Cdc5 is a fascinating multifaceted protein that is programmed to target its many substrates in a timely, sequential manner to ensure proper cell cycle progression. Over the years, many lessons about Polo-like kinase 1 have been learned by studying Cdc5 in budding yeast. Cdc5 has been well documented in regulating mitotic entry, chromosome segregation, mitotic exit, and cytokinesis. Cdc5 also plays important roles during cell division after DNA damage. Here, we briefly review the many functions of Cdc5 and its regulation in the absence and presence of DNA damage.
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Affiliation(s)
- Vladimir V Botchkarev
- Department of Biology, Rosenstiel Basic Medical Sciences Research Center, Brandeis University, Waltham, MA, 02454, USA
- Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, MA, 02215, USA
- Department of Genetics, Harvard Medical School, Boston, MA, 02115, USA
| | - James E Haber
- Department of Biology, Rosenstiel Basic Medical Sciences Research Center, Brandeis University, Waltham, MA, 02454, USA.
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12
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Differential abundance and transcription of 14-3-3 proteins during vegetative growth and sexual reproduction in budding yeast. Sci Rep 2018; 8:2145. [PMID: 29391437 PMCID: PMC5794856 DOI: 10.1038/s41598-018-20284-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2017] [Accepted: 01/16/2018] [Indexed: 12/02/2022] Open
Abstract
14-3-3 is a family of relatively low molecular weight, acidic, dimeric proteins, conserved from yeast to metazoans including humans. Apart from their role in diverse cellular processes, these proteins are also known for their role in several clinical implications. Present proteomic and biochemical comparison showed increased abundance and differential phosphorylation of these proteins in meiotic cells. Double deletion of bmh1−/−bmh2−/− leads to complete absence of sporulation with cells arrested at G1/S phase while further incubation of cells in sporulating media leads to cell death. In silico analysis showed the presence of 14-3-3 interacting motifs in bonafide members of kinetochore complex (KC) and spindle pole body (SPB), while present cell biological data pointed towards the possible role of yeast Bmh1/2 in regulating the behaviour of KC and SPB. We further showed the involvement of 14-3-3 in segregation of genetic material and expression of human 14-3-3β/α was able to complement the function of endogenous 14-3-3 protein even in the complex cellular process like meiosis. Our present data also established haplosufficient nature of BMH1/2. We further showed that proteins synthesized during mitotic growth enter meiotic cells without de novo synthesis except for meiotic-specific proteins required for induction and meiotic progression in Saccharomyces cerevisiae.
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13
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Xiang X. Nuclear movement in fungi. Semin Cell Dev Biol 2017; 82:3-16. [PMID: 29241689 DOI: 10.1016/j.semcdb.2017.10.024] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2017] [Revised: 10/17/2017] [Accepted: 10/23/2017] [Indexed: 12/22/2022]
Abstract
Nuclear movement within a cell occurs in a variety of eukaryotic organisms including yeasts and filamentous fungi. Fungal molecular genetic studies identified the minus-end-directed microtubule motor cytoplasmic dynein as a critical protein for nuclear movement or orientation of the mitotic spindle contained in the nucleus. Studies in the budding yeast first indicated that dynein anchored at the cortex via its anchoring protein Num1 exerts pulling force on an astral microtubule to orient the anaphase spindle across the mother-daughter axis before nuclear division. Prior to anaphase, myosin V interacts with the plus end of an astral microtubule via Kar9-Bim1/EB1 and pulls the plus end along the actin cables to move the nucleus/spindle close to the bud neck. In addition, pushing or pulling forces generated from cortex-linked polymerization or depolymerization of microtubules drive nuclear movements in yeasts and possibly also in filamentous fungi. In filamentous fungi, multiple nuclei within a hyphal segment undergo dynein-dependent back-and-forth movements and their positioning is also influenced by cytoplasmic streaming toward the hyphal tip. In addition, nuclear movement occurs at various stages of fungal development and fungal infection of plant tissues. This review discusses our current understanding on the mechanisms of nuclear movement in fungal organisms, the importance of nuclear positioning and the regulatory strategies that ensure the proper positioning of nucleus/spindle.
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Affiliation(s)
- Xin Xiang
- Department of Biochemistry and Molecular Biology, Uniformed Services University of the Health Sciences - F. Edward Hébert School of Medicine, Bethesda, MD, USA.
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14
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Lengefeld J, Yen E, Chen X, Leary A, Vogel J, Barral Y. Spatial cues and not spindle pole maturation drive the asymmetry of astral microtubules between new and preexisting spindle poles. Mol Biol Cell 2017; 29:10-28. [PMID: 29142076 PMCID: PMC5746063 DOI: 10.1091/mbc.e16-10-0725] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2017] [Revised: 10/31/2017] [Accepted: 11/07/2017] [Indexed: 11/17/2022] Open
Abstract
The distinct behavior of the spindle pole bodies (SPBs) during spindle orientation in yeast metaphase does not result from them being differently mature, but astral microtubule organization correlates with the subcellular position rather than the age of the SPBs. In many asymmetrically dividing cells, the microtubule-organizing centers (MTOCs; mammalian centrosome and yeast spindle pole body [SPB]) nucleate more astral microtubules on one of the two spindle poles than the other. This differential activity generally correlates with the age of MTOCs and contributes to orienting the mitotic spindle within the cell. The asymmetry might result from the two MTOCs being in distinctive maturation states. We investigated this model in budding yeast. Using fluorophores with different maturation kinetics to label the outer plaque components of the SPB, we found that the Cnm67 protein is mobile, whereas Spc72 is not. However, these two proteins were rapidly as abundant on both SPBs, indicating that SPBs mature more rapidly than anticipated. Superresolution microscopy confirmed this finding for Spc72 and for the γ-tubulin complex. Moreover, astral microtubule number and length correlated with the subcellular localization of SPBs rather than their age. Kar9-dependent orientation of the spindle drove the differential activity of the SPBs in astral microtubule organization rather than intrinsic differences between the spindle poles. Together, our data establish that Kar9 and spatial cues, rather than the kinetics of SPB maturation, control the asymmetry of astral microtubule organization between the preexisting and new SPBs.
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Affiliation(s)
- Jette Lengefeld
- Department of Biology, Institute of Biochemistry, ETH Zurich, 8093 Zurich, Switzerland
| | - Eric Yen
- Department of Biology, McGill University, Montreal, QC H3G 0B1, Canada
| | - Xiuzhen Chen
- Department of Biology, Institute of Biochemistry, ETH Zurich, 8093 Zurich, Switzerland
| | - Allen Leary
- Department of Biology, McGill University, Montreal, QC H3G 0B1, Canada
| | - Jackie Vogel
- Department of Biology, McGill University, Montreal, QC H3G 0B1, Canada
| | - Yves Barral
- Department of Biology, Institute of Biochemistry, ETH Zurich, 8093 Zurich, Switzerland
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15
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Geymonat M, Segal M. Intrinsic and Extrinsic Determinants Linking Spindle Pole Fate, Spindle Polarity, and Asymmetric Cell Division in the Budding Yeast S. cerevisiae. Results Probl Cell Differ 2017; 61:49-82. [PMID: 28409300 DOI: 10.1007/978-3-319-53150-2_3] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
The budding yeast S. cerevisiae is a powerful model to understand the multiple layers of control driving an asymmetric cell division. In budding yeast, asymmetric targeting of the spindle poles to the mother and bud cell compartments respectively orients the mitotic spindle along the mother-bud axis. This program exploits an intrinsic functional asymmetry arising from the age distinction between the spindle poles-one inherited from the preceding division and the other newly assembled. Extrinsic mechanisms convert this age distinction into differential fate. Execution of this program couples spindle orientation with the segregation of the older spindle pole to the bud. Remarkably, similar stereotyped patterns of inheritance occur in self-renewing stem cell divisions underscoring the general importance of studying spindle polarity and differential fate in yeast. Here, we review the mechanisms accounting for this pivotal interplay between intrinsic and extrinsic asymmetries that translate spindle pole age into differential fate.
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Affiliation(s)
- Marco Geymonat
- Department of Genetics, University of Cambridge, Downing Street, Cambridge, CB2 3EH, UK
| | - Marisa Segal
- Department of Genetics, University of Cambridge, Downing Street, Cambridge, CB2 3EH, UK.
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16
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Rüthnick D, Neuner A, Dietrich F, Kirrmaier D, Engel U, Knop M, Schiebel E. Characterization of spindle pole body duplication reveals a regulatory role for nuclear pore complexes. J Cell Biol 2017; 216:2425-2442. [PMID: 28659328 PMCID: PMC5551709 DOI: 10.1083/jcb.201612129] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2016] [Revised: 04/25/2017] [Accepted: 05/22/2017] [Indexed: 02/08/2023] Open
Abstract
The spindle pole body (SPB) of budding yeast duplicates once per cell cycle. In G1, the satellite, an SPB precursor, assembles next to the mother SPB (mSPB) on the cytoplasmic side of the nuclear envelope (NE). How the growing satellite subsequently inserts into the NE is an open question. To address this, we have uncoupled satellite growth from NE insertion. We show that the bridge structure that separates the mSPB from the satellite is a distance holder that prevents deleterious fusion of both structures. Binding of the γ-tubulin receptor Spc110 to the central plaque from within the nucleus is important for NE insertion of the new SPB. Moreover, we provide evidence that a nuclear pore complex associates with the duplicating SPB and helps to insert the SPB into the NE. After SPB insertion, membrane-associated proteins including the conserved Ndc1 encircle the SPB and retain it within the NE. Thus, uncoupling SPB growth from NE insertion unmasks functions of the duplication machinery.
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Affiliation(s)
- Diana Rüthnick
- Zentrum für Molekulare Biologie at the University of Heidelberg, German Cancer Research Center-Center for Molecular Biology Alliance, Heidelberg, Germany
| | - Annett Neuner
- Zentrum für Molekulare Biologie at the University of Heidelberg, German Cancer Research Center-Center for Molecular Biology Alliance, Heidelberg, Germany
| | - Franziska Dietrich
- Zentrum für Molekulare Biologie at the University of Heidelberg, German Cancer Research Center-Center for Molecular Biology Alliance, Heidelberg, Germany
| | - Daniel Kirrmaier
- Zentrum für Molekulare Biologie at the University of Heidelberg, German Cancer Research Center-Center for Molecular Biology Alliance, Heidelberg, Germany
| | - Ulrike Engel
- Nikon Imaging Center at the University of Heidelberg, Bioquant, Heidelberg, Germany
| | - Michael Knop
- Zentrum für Molekulare Biologie at the University of Heidelberg, German Cancer Research Center-Center for Molecular Biology Alliance, Heidelberg, Germany
| | - Elmar Schiebel
- Zentrum für Molekulare Biologie at the University of Heidelberg, German Cancer Research Center-Center for Molecular Biology Alliance, Heidelberg, Germany
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17
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Huang J, Liu F, Liu Z, Tang H, Wu H, Gong Q, Chen J. Immune Checkpoint in Glioblastoma: Promising and Challenging. Front Pharmacol 2017; 8:242. [PMID: 28536525 PMCID: PMC5422441 DOI: 10.3389/fphar.2017.00242] [Citation(s) in RCA: 107] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2017] [Accepted: 04/18/2017] [Indexed: 12/18/2022] Open
Abstract
Glioblastoma (GBM) is a severe malignant brain cancer with poor overall survival. Conventional intervention remains dismal to prevent recurrence and deterioration of GBM cell. Recent years have witnessed exciting breakthroughs in novel immune strategies, especially checkpoint inhibitors, some of which have become adjuvant setting after standard of care in melanoma. Several clinical trials of checkpoint inhibitors are ongoing in glioblastoma and other brain carcinomas. Plus, synergistic combinations of checkpoint inhibitors with conventional therapy strategies—radiotherapy, temozolomide, bevacizumab, and corticosteroids are now being exploited and applied in clinical settings. This review highlights the recent developments of checkpoints in GBM immunotherapy to provide a brief and comprehensive review of current treatment options. Furthermore, we will discuss challenges remained, such as unique immune system of central nervous system (CNS), immune-related toxicities, synergies, and adverse interactions of combination therapies.
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Affiliation(s)
- Jing Huang
- Department of Psychiatry, the Second Xiangya Hospital, Central South UniversityChangsha, China.,Mental Health Institute of the Second Xiangya Hospital, Chinese National Clinical Research Center on Mental Disorders (Xiangya), Chinese National Technology Institute on Mental Disorders, Hunan Key Laboratory of Psychiatry and Mental Health, Central South UniversityChangsha, China
| | - Fangkun Liu
- Department of Neurosurgery, Xiangya Hospital, Central South University (CSU)Changsha, China
| | - Zhixiong Liu
- Department of Neurosurgery, Xiangya Hospital, Central South University (CSU)Changsha, China
| | - Hui Tang
- Department of Psychiatry, the Second Xiangya Hospital, Central South UniversityChangsha, China.,Mental Health Institute of the Second Xiangya Hospital, Chinese National Clinical Research Center on Mental Disorders (Xiangya), Chinese National Technology Institute on Mental Disorders, Hunan Key Laboratory of Psychiatry and Mental Health, Central South UniversityChangsha, China
| | - Haishan Wu
- Department of Psychiatry, the Second Xiangya Hospital, Central South UniversityChangsha, China.,Mental Health Institute of the Second Xiangya Hospital, Chinese National Clinical Research Center on Mental Disorders (Xiangya), Chinese National Technology Institute on Mental Disorders, Hunan Key Laboratory of Psychiatry and Mental Health, Central South UniversityChangsha, China
| | - Qianni Gong
- Department of Minimally Invasive Surgery, the Second Xiangya Hospital, Central South UniversityChangsha, China
| | - Jindong Chen
- Department of Psychiatry, the Second Xiangya Hospital, Central South UniversityChangsha, China.,Mental Health Institute of the Second Xiangya Hospital, Chinese National Clinical Research Center on Mental Disorders (Xiangya), Chinese National Technology Institute on Mental Disorders, Hunan Key Laboratory of Psychiatry and Mental Health, Central South UniversityChangsha, China
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18
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The Mitotic Exit Network Regulates Spindle Pole Body Selection During Sporulation of Saccharomyces cerevisiae. Genetics 2017; 206:919-937. [PMID: 28450458 DOI: 10.1534/genetics.116.194522] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2016] [Accepted: 04/11/2017] [Indexed: 01/11/2023] Open
Abstract
Age-based inheritance of centrosomes in eukaryotic cells is associated with faithful chromosome distribution in asymmetric cell divisions. During Saccharomyces cerevisiae ascospore formation, such an inheritance mechanism targets the yeast centrosome equivalents, the spindle pole bodies (SPBs) at meiosis II onset. Decreased nutrient availability causes initiation of spore formation at only the younger SPBs and their associated genomes. This mechanism ensures encapsulation of nonsister genomes, which preserves genetic diversity and provides a fitness advantage at the population level. Here, by usage of an enhanced system for sporulation-induced protein depletion, we demonstrate that the core mitotic exit network (MEN) is involved in age-based SPB selection. Moreover, efficient genome inheritance requires Dbf2/20-Mob1 during a late step in spore maturation. We provide evidence that the meiotic functions of the MEN are more complex than previously thought. In contrast to mitosis, completion of the meiotic divisions does not strictly rely on the MEN whereas its activity is required at different time points during spore development. This is reminiscent of vegetative MEN functions in spindle polarity establishment, mitotic exit, and cytokinesis. In summary, our investigation contributes to the understanding of age-based SPB inheritance during sporulation of S. cerevisiae and provides general insights on network plasticity in the context of a specialized developmental program. Moreover, the improved system for a developmental-specific tool to induce protein depletion will be useful in other biological contexts.
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19
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Kumar R. An account of fungal 14-3-3 proteins. Eur J Cell Biol 2017; 96:206-217. [PMID: 28258766 DOI: 10.1016/j.ejcb.2017.02.006] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2017] [Revised: 02/21/2017] [Accepted: 02/21/2017] [Indexed: 01/09/2023] Open
Abstract
14-3-3s are a group of relatively low molecular weight, acidic, dimeric, protein(s) conserved from single-celled yeast to multicellular vertebrates including humans. Despite lacking catalytic activity, these proteins have been shown to be involved in multiple cellular processes. Apart from their role in normal cellular physiology, recently these proteins have been implicated in various medical consequences. In this present review, fungal 14-3-3 protein localization, interactions, transcription, regulation, their role in the diverse cellular process including DNA duplication, cell cycle, protein trafficking or secretion, apoptosis, autophagy, cell viability under stress, gene expression, spindle positioning, role in carbon metabolism have been discussed. In the end, I also highlighted various roles of yeasts 14-3-3 proteins in tabular form. Thus this review with primary emphasis on yeast will help in appreciating the significance of 14-3-3 proteins in cell physiology.
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Affiliation(s)
- Ravinder Kumar
- Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Powai, Mumbai 400 076, Maharashtra, India.
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20
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Botchkarev VV, Garabedian MV, Lemos B, Paulissen E, Haber JE. The budding yeast Polo-like kinase localizes to distinct populations at centrosomes during mitosis. Mol Biol Cell 2017; 28:1011-1020. [PMID: 28228549 PMCID: PMC5391178 DOI: 10.1091/mbc.e16-05-0324] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2016] [Revised: 01/09/2017] [Accepted: 02/17/2017] [Indexed: 02/02/2023] Open
Abstract
The yeast Polo kinase Cdc5 changes its localization at centrosomes during the cell cycle. Cdc5 localizes to the nuclear centrosome surface in early mitosis and relocalizes to the cytoplasmic centrosome side in late anaphase. Cdc14 and Bfa1 play important roles in regulating Cdc5 centrosome localization. The budding yeast Polo-like kinase Cdc5 is a key regulator of many mitotic events. Cdc5 coordinates its functions spatially and temporally by changing its localization during the cell cycle: Cdc5 is imported into the nucleus in G2 phase and released to the cytoplasm in anaphase, where it accumulates at the bud neck. Cdc5 also localizes to the spindle pole bodies (SPBs) from S phase until the end of mitosis. Whether Cdc5 changes its SPB population during the cell cycle is not known. We find that Cdc5 localizes to distinct SPB subpopulations, depending on the mitotic stage. Cdc5 localizes to the nuclear side of the SPBs during metaphase and early anaphase and to the cytoplasmic surface of the SPBs during late anaphase. Cdc14 is necessary to relocalize Cdc5 from the nuclear SPB plaque. Accumulation of Cdc5 at the daughter SPB in late anaphase is controlled by Bfa1. We also show that Cdc5 and Bfa1 are found in spatially distinct locations at the SPBs during G2/M arrest after DNA damage. Collectively our data reveal that Cdc5 is a dynamic component of the SPBs during mitosis and provide new insight into its regulation during both late mitotic events and DNA damage–induced G2/M arrest.
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Affiliation(s)
- Vladimir V Botchkarev
- Rosenstiel Basic Medical Sciences Research Center and Department of Biology, Brandeis University, Waltham, MA 02454
| | - Mikael V Garabedian
- Rosenstiel Basic Medical Sciences Research Center and Department of Biology, Brandeis University, Waltham, MA 02454
| | - Brenda Lemos
- Rosenstiel Basic Medical Sciences Research Center and Department of Biology, Brandeis University, Waltham, MA 02454
| | - Eric Paulissen
- Rosenstiel Basic Medical Sciences Research Center and Department of Biology, Brandeis University, Waltham, MA 02454
| | - James E Haber
- Rosenstiel Basic Medical Sciences Research Center and Department of Biology, Brandeis University, Waltham, MA 02454
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21
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Caydasi AK, Khmelinskii A, Duenas-Sanchez R, Kurtulmus B, Knop M, Pereira G. Temporal and compartment-specific signals coordinate mitotic exit with spindle position. Nat Commun 2017; 8:14129. [PMID: 28117323 PMCID: PMC5286211 DOI: 10.1038/ncomms14129] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2016] [Accepted: 12/02/2016] [Indexed: 02/06/2023] Open
Abstract
The spatiotemporal control of mitotic exit is crucial for faithful chromosome segregation during mitosis. In budding yeast, the mitotic exit network (MEN) drives cells out of mitosis, whereas the spindle position checkpoint (SPOC) blocks MEN activity when the anaphase spindle is mispositioned. How the SPOC operates at a molecular level remains unclear. Here, we report novel insights into how mitotic signalling pathways orchestrate chromosome segregation in time and space. We establish that the key function of the central SPOC kinase, Kin4, is to counterbalance MEN activation by the cdc fourteen early anaphase release (FEAR) network in the mother cell compartment. Remarkably, Kin4 becomes dispensable for SPOC function in the absence of FEAR. Cells lacking both FEAR and Kin4 show that FEAR contributes to mitotic exit through regulation of the SPOC component Bfa1 and the MEN kinase Cdc15. Furthermore, we uncover controls that specifically promote mitotic exit in the daughter cell compartment. The mitotic exit network (MEN) triggers mitotic exit and can be blocked by the spindle position checkpoint (SPOC). Here the authors show that SPOC kinase Kin4 counterbalances MEN activation by the Cdc fourteen early anaphase release (FEAR) network in the mother cell and that in the absence of FEAR mitotic exit requires daughter cell-confined factors.
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Affiliation(s)
- Ayse Koca Caydasi
- DKFZ-ZMBH Alliance, Department of Cell and Tumour Biology, German Cancer Research Centre (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg, Germany.,Centre for Organismal Studies (COS), University of Heidelberg, Im Neuenheimer Feld 230, 69120 Heidelberg, Germany
| | - Anton Khmelinskii
- DKFZ-ZMBH Alliance, Centre for Molecular Biology (ZMBH), University of Heidelberg, Im Neuenheimer Feld 282, 69120 Heidelberg, Germany
| | - Rafael Duenas-Sanchez
- DKFZ-ZMBH Alliance, Department of Cell and Tumour Biology, German Cancer Research Centre (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg, Germany.,Centre for Organismal Studies (COS), University of Heidelberg, Im Neuenheimer Feld 230, 69120 Heidelberg, Germany
| | - Bahtiyar Kurtulmus
- DKFZ-ZMBH Alliance, Department of Cell and Tumour Biology, German Cancer Research Centre (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg, Germany.,Centre for Organismal Studies (COS), University of Heidelberg, Im Neuenheimer Feld 230, 69120 Heidelberg, Germany
| | - Michael Knop
- DKFZ-ZMBH Alliance, Department of Cell and Tumour Biology, German Cancer Research Centre (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg, Germany.,DKFZ-ZMBH Alliance, Centre for Molecular Biology (ZMBH), University of Heidelberg, Im Neuenheimer Feld 282, 69120 Heidelberg, Germany
| | - Gislene Pereira
- DKFZ-ZMBH Alliance, Department of Cell and Tumour Biology, German Cancer Research Centre (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg, Germany.,Centre for Organismal Studies (COS), University of Heidelberg, Im Neuenheimer Feld 230, 69120 Heidelberg, Germany
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22
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Fox C, Zou J, Rappsilber J, Marston AL. Cdc14 phosphatase directs centrosome re-duplication at the meiosis I to meiosis II transition in budding yeast. Wellcome Open Res 2017. [DOI: 10.12688/wellcomeopenres.10507.1] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
BackgroundGametes are generated through a specialized cell division called meiosis, in which ploidy is reduced by half because two consecutive rounds of chromosome segregation, meiosis I and meiosis II, occur without intervening DNA replication. This contrasts with the mitotic cell cycle where DNA replication and chromosome segregation alternate to maintain the same ploidy. At the end of mitosis, CDKs are inactivated. This low CDK state in late mitosis/G1 allows for critical preparatory events for DNA replication and centrosome/spindle pole body (SPB) duplication. However, their execution is inhibited until S phase, where further preparatory events are also prevented. This “licensing” ensures that both the chromosomes and the centrosomes/SPBs replicate exactly once per cell cycle, thereby maintaining constant ploidy. Crucially, between meiosis I and meiosis II, centrosomes/SPBs must be re-licensed, but DNA re-replication must be avoided. In budding yeast, the Cdc14 protein phosphatase triggers CDK down regulation to promote exit from mitosis. Cdc14 also regulates the meiosis I to meiosis II transition, though its mode of action has remained unclear.MethodsFluorescence and electron microscopy was combined with proteomics to probe SPB duplication in cells with inactive or hyperactive Cdc14.ResultsWe demonstrate that Cdc14 ensures two successive nuclear divisions by re-licensing SPBs at the meiosis I to meiosis II transition. We show that Cdc14 is asymmetrically enriched on a single SPB during anaphase I and provide evidence that this enrichment promotes SPB re-duplication. Cells with impaired Cdc14 activity fail to promote extension of the SPB half-bridge, the initial step in morphogenesis of a new SPB. Conversely, cells with hyper-active Cdc14 duplicate SPBs, but fail to induce their separation.ConclusionOur findings implicate reversal of key CDK-dependent phosphorylations in the differential licensing of cyclical events at the meiosis I to meiosis I transition.
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23
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Fox C, Zou J, Rappsilber J, Marston AL. Cdc14 phosphatase directs centrosome re-duplication at the meiosis I to meiosis II transition in budding yeast. Wellcome Open Res 2017; 2:2. [PMID: 28133632 PMCID: PMC5266553 DOI: 10.12688/wellcomeopenres.10507.2] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Background: Gametes are generated through a specialized cell division called meiosis, in which ploidy is reduced by half because two consecutive rounds of chromosome segregation, meiosis I and meiosis II, occur without intervening DNA replication. This contrasts with the mitotic cell cycle where DNA replication and chromosome segregation alternate to maintain the same ploidy. At the end of mitosis, cyclin-dependent kinases (CDKs) are inactivated. This low CDK state in late mitosis/G1 allows for critical preparatory events for DNA replication and centrosome/spindle pole body (SPB) duplication. However, their execution is inhibited until S phase, where further preparatory events are also prevented. This “licensing” ensures that both the chromosomes and the centrosomes/SPBs replicate exactly once per cell cycle, thereby maintaining constant ploidy. Crucially, between meiosis I and meiosis II, centrosomes/SPBs must be re-licensed, but DNA re-replication must be avoided. In budding yeast, the Cdc14 protein phosphatase triggers CDK down regulation to promote exit from mitosis. Cdc14 also regulates the meiosis I to meiosis II transition, though its mode of action has remained unclear. Methods: Fluorescence and electron microscopy was combined with proteomics to probe SPB duplication in cells with inactive or hyperactive Cdc14. Results: We demonstrate that Cdc14 ensures two successive nuclear divisions by re-licensing SPBs at the meiosis I to meiosis II transition. We show that Cdc14 is asymmetrically enriched on a single SPB during anaphase I and provide evidence that this enrichment promotes SPB re-duplication. Cells with impaired Cdc14 activity fail to promote extension of the SPB half-bridge, the initial step in morphogenesis of a new SPB. Conversely, cells with hyper-active Cdc14 duplicate SPBs, but fail to induce their separation. Conclusion: Our findings implicate reversal of key CDK-dependent phosphorylations in the differential licensing of cyclical events at the meiosis I to meiosis II transition.
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Affiliation(s)
- Colette Fox
- The Wellcome Trust Centre for Cell Biology, Institute of Cell Biology, School of Biological Sciences, Edinburgh, UK
| | - Juan Zou
- The Wellcome Trust Centre for Cell Biology, Institute of Cell Biology, School of Biological Sciences, Edinburgh, UK
| | - Juri Rappsilber
- The Wellcome Trust Centre for Cell Biology, Institute of Cell Biology, School of Biological Sciences, Edinburgh, UK.,Chair of Bioanalytics, Institute of Biotechnology, Technische Universität Berlin, Berlin, Germany
| | - Adele L Marston
- The Wellcome Trust Centre for Cell Biology, Institute of Cell Biology, School of Biological Sciences, Edinburgh, UK
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24
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Abstract
In budding yeast, alignment of the anaphase spindle along the mother-bud axis is crucial for maintaining genome integrity. If the anaphase spindle becomes misaligned in the mother cell compartment, cells arrest in anaphase because the mitotic exit network (MEN), an essential Ras-like GTPase signaling cascade, is inhibited by the spindle position checkpoint (SPoC). Distinct localization patterns of MEN and SPoC components mediate MEN inhibition. Most components of the MEN localize to spindle pole bodies. If the spindle becomes mispositioned in the mother cell compartment, cells arrest in anaphase due to inhibition of the MEN by the mother cell-restricted SPoC kinase Kin4. Here we show that a bud-localized activating signal is necessary for full MEN activation. We identify Lte1 as this signal and show that Lte1 activates the MEN in at least two ways. It inhibits small amounts of Kin4 that are present in the bud via its central domain. An additional MEN-activating function of Lte1 is mediated by its N- and C-terminal GEF domains, which, we propose, directly activate the MEN GTPase Tem1. We conclude that control of the MEN by spindle position is exerted by both negative and positive regulatory elements that control the pathway's GTPase activity.
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Affiliation(s)
- Jill E Falk
- David H. Koch Institute for Integrative Cancer Research, Howard Hughes Medical Institute, Massachusetts Institute of Technology, Cambridge, MA 02139
| | - Ian W Campbell
- David H. Koch Institute for Integrative Cancer Research, Howard Hughes Medical Institute, Massachusetts Institute of Technology, Cambridge, MA 02139
| | - Kelsey Joyce
- Department of Biology, Emmanuel College, Boston, MA 02115
| | - Jenna Whalen
- Department of Biology, Emmanuel College, Boston, MA 02115
| | - Anupama Seshan
- Department of Biology, Emmanuel College, Boston, MA 02115
| | - Angelika Amon
- David H. Koch Institute for Integrative Cancer Research, Howard Hughes Medical Institute, Massachusetts Institute of Technology, Cambridge, MA 02139
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25
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Falk JE, Campbell IW, Joyce K, Whalen J, Seshan A, Amon A. LTE1 promotes exit from mitosis by multiple mechanisms. Mol Biol Cell 2016; 27:3991-4001. [PMID: 27798238 PMCID: PMC5156540 DOI: 10.1091/mbc.e16-08-0563] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2016] [Revised: 10/19/2016] [Accepted: 10/20/2016] [Indexed: 12/22/2022] Open
Abstract
In budding yeast, the spindle position checkpoint ensures that cells exit from mitosis only when their spindle is properly aligned along the mother–bud axis. Exit from mitosis is controlled by both negative signals in the mother cell compartment and positive signals in the bud. In budding yeast, alignment of the anaphase spindle along the mother–bud axis is crucial for maintaining genome integrity. If the anaphase spindle becomes misaligned in the mother cell compartment, cells arrest in anaphase because the mitotic exit network (MEN), an essential Ras-like GTPase signaling cascade, is inhibited by the spindle position checkpoint (SPoC). Distinct localization patterns of MEN and SPoC components mediate MEN inhibition. Most components of the MEN localize to spindle pole bodies. If the spindle becomes mispositioned in the mother cell compartment, cells arrest in anaphase due to inhibition of the MEN by the mother cell–restricted SPoC kinase Kin4. Here we show that a bud-localized activating signal is necessary for full MEN activation. We identify Lte1 as this signal and show that Lte1 activates the MEN in at least two ways. It inhibits small amounts of Kin4 that are present in the bud via its central domain. An additional MEN-activating function of Lte1 is mediated by its N- and C-terminal GEF domains, which, we propose, directly activate the MEN GTPase Tem1. We conclude that control of the MEN by spindle position is exerted by both negative and positive regulatory elements that control the pathway’s GTPase activity.
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Affiliation(s)
- Jill E Falk
- David H. Koch Institute for Integrative Cancer Research, Howard Hughes Medical Institute, Massachusetts Institute of Technology, Cambridge, MA 02139
| | - Ian W Campbell
- David H. Koch Institute for Integrative Cancer Research, Howard Hughes Medical Institute, Massachusetts Institute of Technology, Cambridge, MA 02139
| | - Kelsey Joyce
- Department of Biology, Emmanuel College, Boston, MA 02115
| | - Jenna Whalen
- Department of Biology, Emmanuel College, Boston, MA 02115
| | - Anupama Seshan
- Department of Biology, Emmanuel College, Boston, MA 02115
| | - Angelika Amon
- David H. Koch Institute for Integrative Cancer Research, Howard Hughes Medical Institute, Massachusetts Institute of Technology, Cambridge, MA 02139
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