1
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Durant M, Mucelli X, Huang LS. Meiotic Cytokinesis in Saccharomyces cerevisiae: Spores That Just Need Closure. J Fungi (Basel) 2024; 10:132. [PMID: 38392804 PMCID: PMC10890087 DOI: 10.3390/jof10020132] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2024] [Revised: 01/30/2024] [Accepted: 02/04/2024] [Indexed: 02/24/2024] Open
Abstract
In the budding yeast Saccharomyces cerevisiae, sporulation occurs during starvation of a diploid cell and results in the formation of four haploid spores forming within the mother cell ascus. Meiosis divides the genetic material that is encapsulated by the prospore membrane that grows to surround the haploid nuclei; this membrane will eventually become the plasma membrane of the haploid spore. Cellularization of the spores occurs when the prospore membrane closes to capture the haploid nucleus along with some cytoplasmic material from the mother cell, and thus, closure of the prospore membrane is the meiotic cytokinetic event. This cytokinetic event involves the removal of the leading-edge protein complex, a complex of proteins that localizes to the leading edge of the growing prospore membrane. The development and closure of the prospore membrane must be coordinated with other meiotic exit events such as spindle disassembly. Timing of the closure of the prospore membrane depends on the meiotic exit pathway, which utilizes Cdc15, a Hippo-like kinase, and Sps1, an STE20 family GCKIII kinase, acting in parallel to the E3 ligase Ama1-APC/C. This review describes the sporulation process and focuses on the development of the prospore membrane and the regulation of prospore membrane closure.
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Affiliation(s)
- Matthew Durant
- Department of Biology, University of Massachusetts Boston, Boston, MA 02125, USA
| | - Xheni Mucelli
- Department of Biology, University of Massachusetts Boston, Boston, MA 02125, USA
| | - Linda S Huang
- Department of Biology, University of Massachusetts Boston, Boston, MA 02125, USA
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2
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A continuous-time stochastic Boolean model provides a quantitative description of the budding yeast cell cycle. Sci Rep 2022; 12:20302. [PMID: 36434030 PMCID: PMC9700812 DOI: 10.1038/s41598-022-24302-6] [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: 06/27/2022] [Accepted: 11/14/2022] [Indexed: 11/26/2022] Open
Abstract
The cell division cycle is regulated by a complex network of interacting genes and proteins. The control system has been modeled in many ways, from qualitative Boolean switching-networks to quantitative differential equations and highly detailed stochastic simulations. Here we develop a continuous-time stochastic model using seven Boolean variables to represent the activities of major regulators of the budding yeast cell cycle plus one continuous variable representing cell growth. The Boolean variables are updated asynchronously by logical rules based on known biochemistry of the cell-cycle control system using Gillespie's stochastic simulation algorithm. Time and cell size are updated continuously. By simulating a population of yeast cells, we calculate statistical properties of cell cycle progression that can be compared directly to experimental measurements. Perturbations of the normal sequence of events indicate that the cell cycle is 91% robust to random 'flips' of the Boolean variables, but 9% of the perturbations induce lethal mistakes in cell cycle progression. This simple, hybrid Boolean model gives a good account of the growth and division of budding yeast cells, suggesting that this modeling approach may be as accurate as detailed reaction-kinetic modeling with considerably less demands on estimating rate constants.
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3
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Jeong SM, Bui QT, Kwak M, Lee JY, Lee PCW. Targeting Cdc20 for cancer therapy. Biochim Biophys Acta Rev Cancer 2022; 1877:188824. [DOI: 10.1016/j.bbcan.2022.188824] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2022] [Revised: 09/26/2022] [Accepted: 10/06/2022] [Indexed: 11/26/2022]
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4
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Adler SO, Spiesser TW, Uschner F, Münzner U, Hahn J, Krantz M, Klipp E. A yeast cell cycle model integrating stress, signaling, and physiology. FEMS Yeast Res 2022; 22:6592118. [PMID: 35617157 PMCID: PMC9246278 DOI: 10.1093/femsyr/foac026] [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: 01/14/2022] [Revised: 04/22/2022] [Accepted: 05/23/2022] [Indexed: 11/25/2022] Open
Abstract
The cell division cycle in eukaryotic cells is a series of highly coordinated molecular interactions that ensure that cell growth, duplication of genetic material, and actual cell division are precisely orchestrated to give rise to two viable progeny cells. Moreover, the cell cycle machinery is responsible for incorporating information about external cues or internal processes that the cell must keep track of to ensure a coordinated, timely progression of all related processes. This is most pronounced in multicellular organisms, but also a cardinal feature in model organisms such as baker's yeast. The complex and integrative behavior is difficult to grasp and requires mathematical modeling to fully understand the quantitative interplay of the single components within the entire system. Here, we present a self-oscillating mathematical model of the yeast cell cycle that comprises all major cyclins and their main regulators. Furthermore, it accounts for the regulation of the cell cycle machinery by a series of external stimuli such as mating pheromones and changes in osmotic pressure or nutrient quality. We demonstrate how the external perturbations modify the dynamics of cell cycle components and how the cell cycle resumes after adaptation to or relief from stress.
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Affiliation(s)
- Stephan O Adler
- Theoretical Biophysics, Humboldt-Universität zu Berlin, Invalidenstr. 42, 10115 Berlin, Germany
| | - Thomas W Spiesser
- Theoretical Biophysics, Humboldt-Universität zu Berlin, Invalidenstr. 42, 10115 Berlin, Germany
| | - Friedemann Uschner
- Theoretical Biophysics, Humboldt-Universität zu Berlin, Invalidenstr. 42, 10115 Berlin, Germany.,Institute for Medical Informatics and Biometry, Technische Universität Dresden, Fetscherstr. 74, 01307 Dresden, Sachsen, Germany
| | - Ulrike Münzner
- Theoretical Biophysics, Humboldt-Universität zu Berlin, Invalidenstr. 42, 10115 Berlin, Germany.,Laboratory of Cell Systems, Institute for Protein Research, Osaka University, 3-2 Yamadaoka, 565-0871, Suita, Osaka, Japan
| | - Jens Hahn
- Theoretical Biophysics, Humboldt-Universität zu Berlin, Invalidenstr. 42, 10115 Berlin, Germany
| | - Marcus Krantz
- Theoretical Biophysics, Humboldt-Universität zu Berlin, Invalidenstr. 42, 10115 Berlin, Germany
| | - Edda Klipp
- Theoretical Biophysics, Humboldt-Universität zu Berlin, Invalidenstr. 42, 10115 Berlin, Germany
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5
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Lázari LC, Wolf IR, Schnepper AP, Valente GT. LncRNAs of Saccharomyces cerevisiae bypass the cell cycle arrest imposed by ethanol stress. PLoS Comput Biol 2022; 18:e1010081. [PMID: 35587936 PMCID: PMC9232138 DOI: 10.1371/journal.pcbi.1010081] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2021] [Revised: 06/24/2022] [Accepted: 04/05/2022] [Indexed: 11/19/2022] Open
Abstract
Ethanol alters many subsystems of Saccharomyces cerevisiae, including the cell cycle. Two ethanol-responsive lncRNAs in yeast interact with cell cycle proteins, and here, we investigated the role of these RNAs in cell cycle. Our network dynamic modeling showed that higher and lower ethanol-tolerant strains undergo cell cycle arrest in mitosis and G1 phases, respectively, during ethanol stress. The higher population rebound of the lower ethanol-tolerant phenotype after stress relief responds to the late phase arrest. We found that the lncRNA lnc9136 of SEY6210 (a lower ethanol-tolerant strain) induces cells to skip mitosis arrest. Simulating an overexpression of lnc9136 and analyzing CRISPR–Cas9 mutants lacking this lncRNA suggest that lnc9136 induces a regular cell cycle even under ethanol stress, indirectly regulating Swe1p and Clb1/2 by binding to Gin4p and Hsl1p. Notably, lnc10883 of BY4742 (a higher ethanol-tolerant strain) does not prevent G1 arrest in this strain under ethanol stress. However, lnc19883 circumvents DNA and spindle damage checkpoints, maintaining a functional cell cycle by interacting with Mec1p or Bub1p even in the presence of DNA/spindle damage. Overall, we present the first evidence of direct roles for lncRNAs in regulating yeast cell cycle proteins, the dynamics of this system in different ethanol-tolerant phenotypes, and a new yeast cell cycle model. Ethanol is a cell stressor in yeast that dampen ethanol production. LncRNAs are RNAs that control many cellular processes. Computational simulations allow us to study the dynamism of cell systems. Therefore, we built a computational model of the yeast cell cycle to investigate how cells respond to ethanol stress. Simulations showed that ethanol stress or spindle damage arrests the cell cycle. Furthermore, the performance of higher and lower ethanol-tolerant strains in poststress recovery growth seems to be related to the cell cycle phase in which cells are stalled. However, two lncRNAs maintain the activity of the cell cycle even in yeast cells under these stresses by repressing specific cell cycle proteins. Finally, this model facilitates analyses of the yeast cell cycle for applied or basic science purposes.
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Affiliation(s)
- Lucas Cardoso Lázari
- Department of Parasitology, Institute of Biomedical Sciences, Sāo Paulo University (USP), Sao Paulo, Brazil
- Department of Bioprocess and Biotechnology, School of Agriculture, Sao Paulo State University (UNESP), Botucatu, Brazil
| | - Ivan Rodrigo Wolf
- Department of Bioprocess and Biotechnology, School of Agriculture, Sao Paulo State University (UNESP), Botucatu, Brazil
- Department of Structural and Functional Biology, Institute of Bioscience at Botucatu, Sao Paulo State University (UNESP), Botucatu, Brazil
| | - Amanda Piveta Schnepper
- Department of Bioprocess and Biotechnology, School of Agriculture, Sao Paulo State University (UNESP), Botucatu, Brazil
| | - Guilherme Targino Valente
- Department of Bioprocess and Biotechnology, School of Agriculture, Sao Paulo State University (UNESP), Botucatu, Brazil
- Max Planck Institute for Heart and Lung Research, Bad Nauheim, Germany
- * E-mail: ,
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6
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Greenwood BL, Stuart DT. Synchronization of Saccharomyces cerevisiae Cells for Analysis of Progression Through the Cell Cycle. Methods Mol Biol 2022; 2579:145-168. [PMID: 36045205 DOI: 10.1007/978-1-0716-2736-5_12] [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] [Indexed: 06/15/2023]
Abstract
The cell division cycle is a fundamental process required for proliferation of all living organisms. The eukaryotic cell cycle follows a basic template with an ordered series of events beginning with G1 (Gap1) phase, followed successively by S (Synthesis) phase, G2 (Gap 2) phase, and M-phase (Mitosis). The process is tightly regulated in response to signals from both the internal and external milieu. The budding yeast S. cerevisiae is an outstanding model for the study of the cell cycle and its regulatory process. The basic events and regulatory processes of the S. cerevisiae cell cycle are highly conserved with other eukaryotes. The organism grows rapidly in simple medium, has a sequenced annotated genome, well-established genetics, and is amenable to analysis by proteomics and microscopy. Additionally, a range of tools and techniques are available to generate cultures of S. cerevisiae that are homogenously arrested or captured at specific phases of the cell cycle and upon release from that arrest these can be used to monitor cell cycle events as the cells synchronously proceed through a division cycle. In this chapter, we describe a series of commonly used techniques that are used to generate synchronized populations of S. cerevisiae and provide an overview of methods that can be used to monitor the progression of the cells through the cell division cycle.
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Affiliation(s)
| | - David T Stuart
- Department of Biochemistry, University of Alberta, Edmonton, AB, Canada.
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7
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Hayashi H, Kishi T. A Set of Plasmid-Based Modules for Easy Switching of C-Terminal Epitope Tags in Saccharomyces cerevisiae. Microorganisms 2021; 9:2505. [PMID: 34946108 PMCID: PMC8707574 DOI: 10.3390/microorganisms9122505] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2021] [Revised: 11/29/2021] [Accepted: 11/30/2021] [Indexed: 11/24/2022] Open
Abstract
Epitope tagging is a powerful strategy for analyzing the functions of targeted proteins. The use of this strategy has become more convenient with the development of the epitope switch, which is another type of epitope tagging designed to convert the previously tagged epitopes on the chromosome to other epitopes of interest. Various modules for C-terminal epitope switching have been developed and amplified using the one-step polymerase chain reaction (PCR) method before transformation. However, PCR amplification occasionally generates mutations that affect the fidelity of epitope switching. Here, we constructed several plasmids to isolate modules for epitope switching through digestion by restriction enzymes. The isolated modules contained DNA sequences for homologous recombination, various epitopes (13×Myc, 6×HA, GFP, Venus, YFP, mCherry, and CFP), and a transformation marker (Candida glabrata LEU2). The restriction enzyme-digested plasmids were used to directly transform the cells for epitope switching. We demonstrate the efficient and accurate switching of the MX6 module-based C-terminal tandem affinity purification tags to each aforementioned epitope. We believe that our plasmids can serve as powerful tools for the functional analysis of yeast proteins.
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Affiliation(s)
| | - Tsutomu Kishi
- College of Engineering, Nihon University, Koriyama, Fukushima 963-8642, Japan;
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8
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Niwa T, Akaike Y, Watanabe K, Chibazakura T. Hyperactivation of cyclin A-CDK induces centrosome overduplication and chromosome tetraploidization in mouse cells. Biochem Biophys Res Commun 2021; 549:91-97. [PMID: 33667714 DOI: 10.1016/j.bbrc.2021.02.079] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2021] [Accepted: 02/18/2021] [Indexed: 11/17/2022]
Abstract
Mammalian cyclin A-CDK (cyclin-dependent kinase) activity during mitotic exit is regulated by two redundant pathways, cyclin degradation and CDK inhibitors (CKIs). Ectopic expression of a destruction box-truncated (thereby stabilized) mutant of cyclin A in the mouse embryonic fibroblasts nullizygous for three CKIs (p21, p27, and p107) results in constitutive activation ("hyperactivation") of cyclin A-CDK and induces rapid tetraploidization, suggesting loss of the two redundant pathways causes genomic instability. To elucidate the mechanism underlying teraploidization by hyperactive cyclin A-CDK, we first examined if the induction of tetraploidization depends on specific cell cycle stage(s). Arresting the cell cycle at either S phase or M phase blocked the induction of tetraploidization, which was restored by subsequent release from the arrest. These results suggest that both S- and M-phase progressions are necessary for the tetraploidization by hyperactive cyclin A-CDK and that the tetraploidization is not caused by chromosome endoreduplication but by mitotic failure. We also observed that the induction of tetraploidization is associated with excessive duplication of centrosomes, which was suppressed by S-phase but not M-phase block, suggesting that hyperactive cyclin A-CDK promotes centrosome overduplication during S phase. Time-lapse microscopy revealed that hyperactive cyclin A-CDK can lead cells to bypass cell division and enter pseudo-G1 state. These observations implicate that hyperactive cyclin A-CDK causes centrosome overduplication, which leads to mitotic slippage and subsequent tetraploidization.
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Affiliation(s)
- Tetsuo Niwa
- Department of Bioscience, Tokyo University of Agriculture, 1-1-1 Sakuragaoka, Setagaya-ku, Tokyo, 156-8502, Japan
| | - Yasunori Akaike
- Department of Bioscience, Tokyo University of Agriculture, 1-1-1 Sakuragaoka, Setagaya-ku, Tokyo, 156-8502, Japan
| | - Kaichi Watanabe
- Department of Bioscience, Tokyo University of Agriculture, 1-1-1 Sakuragaoka, Setagaya-ku, Tokyo, 156-8502, Japan
| | - Taku Chibazakura
- Department of Bioscience, Tokyo University of Agriculture, 1-1-1 Sakuragaoka, Setagaya-ku, Tokyo, 156-8502, Japan.
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9
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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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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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Zhao Y, Wang D, Zhang Z, Lu Y, Yang X, Ouyang Q, Tang C, Li F. Critical slowing down and attractive manifold: A mechanism for dynamic robustness in the yeast cell-cycle process. Phys Rev E 2020; 101:042405. [PMID: 32422801 DOI: 10.1103/physreve.101.042405] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2019] [Accepted: 01/13/2020] [Indexed: 11/07/2022]
Abstract
Biological processes that execute complex multiple functions, such as the cell cycle, must ensure the order of sequential events and maintain dynamic robustness against various fluctuations. Here, we examine the mechanisms and fundamental structure that achieve these properties in the cell cycle of the budding yeast Saccharomyces cerevisiae. We show that this process behaves like an excitable system containing three well-decoupled saddle-node bifurcations to execute DNA replication and mitosis events. The yeast cell-cycle regulatory network can be divided into three modules-the G1/S phase, early M phase, and late M phase-wherein both positive feedback loops in each module and interactions among modules play important roles. Specifically, when the cell-cycle process operates near the critical points of the saddle-node bifurcations, a critical slowing down effect takes place. Such interregnum then allows for an attractive manifold and sufficient duration for cell-cycle events, within which to assess the completion of DNA replication and mitosis, e.g., spindle assembly. Moreover, such arrangement ensures that any fluctuation in an early module or event will not transmit to a later module or event. Thus, our results suggest a possible dynamical mechanism of the cell-cycle process to ensure event order and dynamic robustness and give insight into the evolution of eukaryotic cell-cycle processes.
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Affiliation(s)
- Yao Zhao
- School of Physics, Peking University, Beijing 100871, China.,Center for Quantitative Biology, Peking University, Beijing 100871, China
| | - Dedi Wang
- School of Physics, Peking University, Beijing 100871, China.,Center for Quantitative Biology, Peking University, Beijing 100871, China
| | - Zhiwen Zhang
- School of Physics, Peking University, Beijing 100871, China.,Center for Quantitative Biology, Peking University, Beijing 100871, China
| | - Ying Lu
- Department of Systems Biology, Harvard Medical School, Boston, Massachusetts 02115, USA
| | - Xiaojing Yang
- Center for Quantitative Biology, Peking University, Beijing 100871, China
| | - Qi Ouyang
- School of Physics, Peking University, Beijing 100871, China.,Center for Quantitative Biology, Peking University, Beijing 100871, China
| | - Chao Tang
- School of Physics, Peking University, Beijing 100871, China.,Center for Quantitative Biology, Peking University, Beijing 100871, China
| | - Fangting Li
- School of Physics, Peking University, Beijing 100871, China.,Center for Quantitative Biology, Peking University, Beijing 100871, China
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12
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Machín F, Ayra-Plasencia J. Are Anaphase Events Really Irreversible? The Endmost Stages of Cell Division and the Paradox of the DNA Double-Strand Break Repair. Bioessays 2020; 42:e2000021. [PMID: 32363600 DOI: 10.1002/bies.202000021] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2020] [Revised: 03/16/2020] [Indexed: 12/25/2022]
Abstract
It has been recently demonstrated that yeast cells are able to partially regress chromosome segregation in telophase as a response to DNA double-strand breaks (DSBs), likely to find a donor sequence for homology-directed repair (HDR). This regression challenges the traditional concept that establishes anaphase events as irreversible, hence opening a new field of research in cell biology. Here, the nature of this new behavior in yeast is summarized and the underlying mechanisms are speculated about. It is also discussed whether it can be reproduced in other eukaryotes. Overall, this work brings forwards the need of understanding how cells attempt to repair DSBs when transiting the latest stages of mitosis, i.e., anaphase and telophase.
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Affiliation(s)
- Félix Machín
- Unidad de Investigación, Hospital Universitario Nuestra Señora de Candelaria, Santa Cruz de Tenerife, 38010, Spain.,Instituto de Tecnologías Biomédicas, Universidad de La Laguna, Santa Cruz de Tenerife, 38200, Spain.,Universidad Fernando Pessoa Canarias, Las Palmas de Gran Canaria, 35450, Spain
| | - Jessel Ayra-Plasencia
- Unidad de Investigación, Hospital Universitario Nuestra Señora de Candelaria, Santa Cruz de Tenerife, 38010, Spain.,Instituto de Tecnologías Biomédicas, Universidad de La Laguna, Santa Cruz de Tenerife, 38200, Spain
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13
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Corno A, Chiroli E, Gross F, Vernieri C, Matafora V, Maffini S, Cosentino Lagomarsino M, Bachi A, Ciliberto A. Cellular response upon proliferation in the presence of an active mitotic checkpoint. Life Sci Alliance 2019; 2:2/3/e201900380. [PMID: 31068378 PMCID: PMC6507650 DOI: 10.26508/lsa.201900380] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2019] [Revised: 04/26/2019] [Accepted: 04/29/2019] [Indexed: 11/24/2022] Open
Abstract
Cells that replicate with an active mitotic checkpoint remain capable to mount multiple times an efficient arrest, are bigger than unperturbed cells, rely more heavily on Cdh1, and have an altered protein expression profile. Eukaryotic cells treated with microtubule-targeting agents activate the spindle assembly checkpoint to arrest in mitosis and prevent chromosome mis-segregation. A fraction of mitotically arrested cells overcomes the block and proliferates even under persistent checkpoint-activating conditions. Here, we asked what allows proliferation in such unfavourable conditions. We report that yeast cells are delayed in mitosis at each division, implying that their spindle assembly checkpoint remains responsive. The arrest causes their cell cycle to be elongated and results in a size increase. Growth saturates at mitosis and correlates with the repression of various factors involved in translation. Contrary to unperturbed cells, growth of cells with an active checkpoint requires Cdh1. This peculiar cell cycle correlates with global changes in protein expression whose signatures partly overlap with the environmental stress response. Hence, cells dividing with an active checkpoint develop recognisable specific traits that allow them to successfully complete cell division notwithstanding a constant mitotic checkpoint arrest. These properties distinguish them from unperturbed cells. Our observation may have implications for the identification of new therapeutic windows and targets in tumors.
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Affiliation(s)
- Andrea Corno
- Istituto Firc di Oncologia Molecolare, Milan, Italy
| | | | | | - Claudio Vernieri
- Istituto Firc di Oncologia Molecolare, Milan, Italy.,Medical Oncology Department, Fondazione IRCCS Istituto Nazionale Tumori, Milan, Italy
| | | | - Stefano Maffini
- Department of Mechanistic Cell Biology, Max Planck Institute of Molecular Physiology, Dortmund, Germany
| | | | - Angela Bachi
- Istituto Firc di Oncologia Molecolare, Milan, Italy
| | - Andrea Ciliberto
- Istituto Firc di Oncologia Molecolare, Milan, Italy .,Istituto di Genetica Molecolare, Consiglio Nazionale delle Ricerche, Pavia, Italy
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14
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Cho CY, Motta FC, Kelliher CM, Deckard A, Haase SB. Reconciling conflicting models for global control of cell-cycle transcription. Cell Cycle 2017; 16:1965-1978. [PMID: 28934013 PMCID: PMC5638368 DOI: 10.1080/15384101.2017.1367073] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2017] [Accepted: 08/07/2017] [Indexed: 10/18/2022] Open
Abstract
Models for the control of global cell-cycle transcription have advanced from a CDK-APC/C oscillator, a transcription factor (TF) network, to coupled CDK-APC/C and TF networks. Nonetheless, current models were challenged by a recent study that concluded that the cell-cycle transcriptional program is primarily controlled by a CDK-APC/C oscillator in budding yeast. Here we report an analysis of the transcriptome dynamics in cyclin mutant cells that were not queried in the previous study. We find that B-cyclin oscillation is not essential for control of phase-specific transcription. Using a mathematical model, we demonstrate that the function of network TFs can be retained in the face of significant reductions in transcript levels. Finally, we show that cells arrested at mitotic exit with non-oscillating levels of B-cyclins continue to cycle transcriptionally. Taken together, these findings support a critical role of a TF network and a requirement for CDK activities that need not be periodic.
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Affiliation(s)
- Chun-Yi Cho
- Department of Biology, Duke University, Durham, NC, USA
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15
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Powers BL, Hall MC. Re-examining the role of Cdc14 phosphatase in reversal of Cdk phosphorylation during mitotic exit. J Cell Sci 2017; 130:2673-2681. [PMID: 28663385 DOI: 10.1242/jcs.201012] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2016] [Accepted: 06/26/2017] [Indexed: 01/12/2023] Open
Abstract
Inactivation of cyclin-dependent kinase (Cdk) and reversal of Cdk phosphorylation are universally required for mitotic exit. In budding yeast (Saccharomyces cerevisiae), Cdc14 is essential for both and thought to be the major Cdk-counteracting phosphatase. However, Cdc14 is not required for mitotic exit in many eukaryotes, despite highly conserved biochemical properties. The question of how similar enzymes could have such disparate influences on mitotic exit prompted us to re-examine the contribution of budding yeast Cdc14. By using an auxin-inducible degron, we show that severe Cdc14 depletion has no effect on the kinetics of mitotic exit and bulk Cdk substrate dephosphorylation, but causes a cell separation defect and is ultimately lethal. Phosphoproteomic analysis revealed that Cdc14 is highly selective for distinct Cdk sites in vivo and does not catalyze widespread Cdk substrate dephosphorylation. We conclude that additional phosphatases likely contribute substantially to Cdk substrate dephosphorylation and coordination of mitotic exit in budding yeast, similar to in other eukaryotes, and the critical mitotic exit functions of Cdc14 require trace amounts of enzyme. We propose that Cdc14 plays very specific, and often different, roles in counteracting Cdk phosphorylation in all species.
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Affiliation(s)
- Brendan L Powers
- Department of Biochemistry and Center for Cancer Research, Purdue University, West Lafayette, IN 47907, USA
| | - Mark C Hall
- Department of Biochemistry and Center for Cancer Research, Purdue University, West Lafayette, IN 47907, USA
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16
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Wang R, Burton JL, Solomon MJ. Transcriptional and post-transcriptional regulation of Cdc20 during the spindle assembly checkpoint in S. cerevisiae. Cell Signal 2017; 33:41-48. [PMID: 28189585 DOI: 10.1016/j.cellsig.2017.02.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2016] [Revised: 01/21/2017] [Accepted: 02/06/2017] [Indexed: 01/26/2023]
Abstract
The anaphase-promoting complex (APC) is a ubiquitin ligase responsible for promoting the degradation of many cell cycle regulators. One of the activators and substrate-binding proteins for the APC is Cdc20. It has been shown previously that Cdc20 can promote its own degradation by the APC in normal cycling cells mainly through a cis-degradation mode (i.e. via an intramolecular mechanism). However, how Cdc20 is degraded during the spindle assembly checkpoint (SAC) is still not fully clear. In this study, we used a dual-Cdc20 system to investigate this issue and found that the cis-degradation mode is also the major pathway responsible for Cdc20 degradation during the SAC. In addition, we found that there is an inverse relationship between APCCdc20 activity and the transcriptional activity of the CDC20 promoter, which likely occurs through feedback regulation by APCCdc20 substrates, such as the cyclins Clb2 and Clb5. These findings contribute to our understanding of how the inhibition of APCCdc20 activity and enhanced Cdc20 degradation are required for proper spindle checkpoint arrest.
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Affiliation(s)
- Ruiwen Wang
- Institute of Life Sciences, College of Biological Science and Engineering, Fuzhou University, Fuzhou, Fujian Province 350108, China.
| | - Janet L Burton
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06520-8114, USA
| | - Mark J Solomon
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06520-8114, USA.
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17
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Degradation of the Mitotic Cyclin Clb3 Is not Required for Mitotic Exit but Is Necessary for G1 Cyclin Control of the Succeeding Cell Cycle. Genetics 2016; 204:1479-1494. [PMID: 27794027 DOI: 10.1534/genetics.116.194837] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2016] [Accepted: 10/25/2016] [Indexed: 02/07/2023] Open
Abstract
B-type cyclins promote mitotic entry and inhibit mitotic exit. In Saccharomyces cerevisiae, four B-type cyclins, Clb1-4, carry out essential mitotic roles, with substantial but incomplete overlap of function among them. Previous work in many organisms has indicated that B-type cyclin-dependent inhibition of mitotic exit imposes a requirement for mitotic destruction of B-type cyclins. For instance, precise genomic removal of the Clb2 destruction box (D box) prevents mitotic proteolysis of Clb2, and blocks mitotic exit. Here, we show that, despite significant functional overlap between Clb2 and Clb3, D-box-dependent Clb3 proteolysis is completely dispensable for mitotic exit. Removal of the Clb3 D box results in abundant Clb3 protein and associated kinase throughout the cell cycle, but mitotic exit occurs with close to normal timing. Clb3 degradation is required for pre-Start G1 control in the succeeding cell cycle. Deleting the CLB3 D box essentially eliminates all time delay before cell cycle Start following division, even in very small newborn cells. CLB3∆db cells show no cell cycle arrest response to mating pheromone, and CLB3∆db completely bypasses the requirement for CLN G1 cyclins, even in the absence of the early expressed B-type cyclins CLB5,6 Thus, regulated mitotic proteolysis of Clb3 is specifically required to make passage of Start in the succeeding cell cycle "memoryless"-dependent on conditions within that cycle, and independent of events such as B-type cyclin accumulation that occurred in the preceding cycle.
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18
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Chen C, Lim HH, Shi J, Tamura S, Maeshima K, Surana U, Gan L. Budding yeast chromatin is dispersed in a crowded nucleoplasm in vivo. Mol Biol Cell 2016; 27:3357-3368. [PMID: 27605704 PMCID: PMC5170867 DOI: 10.1091/mbc.e16-07-0506] [Citation(s) in RCA: 60] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2016] [Accepted: 09/01/2016] [Indexed: 11/11/2022] Open
Abstract
Chromatin organization has an important role in the regulation of eukaryotic systems. Although recent studies have refined the three-dimensional models of chromatin organization with high resolution at the genome sequence level, little is known about how the most fundamental units of chromatin-nucleosomes-are positioned in three dimensions in vivo. Here we use electron cryotomography to study chromatin organization in the budding yeast Saccharomyces cerevisiae Direct visualization of yeast nuclear densities shows no evidence of 30-nm fibers. Aside from preribosomes and spindle microtubules, few nuclear structures are larger than a tetranucleosome. Yeast chromatin does not form compact structures in interphase or mitosis and is consistent with being in an "open" configuration that is conducive to high levels of transcription. From our study and those of others, we propose that yeast can regulate its transcription using local nucleosome-nucleosome associations.
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Affiliation(s)
- Chen Chen
- Department of Biological Sciences and Centre for BioImaging Sciences, National University of Singapore, Singapore 117543, Singapore
| | - Hong Hwa Lim
- Institute of Molecular and Cell Biology, Agency for Science Technology and Research, Proteos, Singapore 138673, Singapore.,Bioprocessing Technology Institute, Singapore 138668, Singapore
| | - Jian Shi
- Department of Biological Sciences and Centre for BioImaging Sciences, National University of Singapore, Singapore 117543, Singapore
| | - Sachiko Tamura
- National Institute of Genetics and Sokendai, Graduate University for Advanced Studies, Mishima, Shizuoka 411-8540, Japan
| | - Kazuhiro Maeshima
- National Institute of Genetics and Sokendai, Graduate University for Advanced Studies, Mishima, Shizuoka 411-8540, Japan
| | - Uttam Surana
- Institute of Molecular and Cell Biology, Agency for Science Technology and Research, Proteos, Singapore 138673, Singapore.,Bioprocessing Technology Institute, Singapore 138668, Singapore.,Department of Pharmacology, National University of Singapore, Singapore 117543, Singapore
| | - Lu Gan
- Department of Biological Sciences and Centre for BioImaging Sciences, National University of Singapore, Singapore 117543, Singapore
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19
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Höckner S, Neumann-Arnold L, Seufert W. Dual control by Cdk1 phosphorylation of the budding yeast APC/C ubiquitin ligase activator Cdh1. Mol Biol Cell 2016; 27:2198-212. [PMID: 27226481 PMCID: PMC4945139 DOI: 10.1091/mbc.e15-11-0787] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2015] [Accepted: 05/18/2016] [Indexed: 12/15/2022] Open
Abstract
The antagonism between cyclin-dependent kinases (Cdks) and the ubiquitin ligase APC/C-Cdh1 is central to eukaryotic cell cycle control. APC/C-Cdh1 targets cyclin B and other regulatory proteins for degradation, whereas Cdks disable APC/C-Cdh1 through phosphorylation of the Cdh1 activator protein at multiple sites. Budding yeast Cdh1 carries nine Cdk phosphorylation sites in its N-terminal regulatory domain, most or all of which contribute to inhibition. However, the precise role of individual sites has remained unclear. Here, we report that the Cdk phosphorylation sites of yeast Cdh1 are organized into autonomous subgroups and act through separate mechanisms. Cdk sites 1-3 had no direct effect on the APC/C binding of Cdh1 but inactivated a bipartite nuclear localization sequence (NLS) and thereby controlled the partitioning of Cdh1 between cytoplasm and nucleus. In contrast, Cdk sites 4-9 did not influence the cell cycle-regulated localization of Cdh1 but prevented its binding to the APC/C. Cdk sites 4-9 reside near two recently identified APC/C interaction motifs in a pattern conserved with the human Cdh1 orthologue. Thus a Cdk-inhibited NLS goes along with Cdk-inhibited APC/C binding sites in yeast Cdh1 to relay the negative control by Cdk1 phosphorylation of the ubiquitin ligase APC/C-Cdh1.
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Affiliation(s)
- Sebastian Höckner
- Department of Genetics, University of Regensburg, D-93040 Regensburg, Germany
| | - Lea Neumann-Arnold
- Department of Genetics, University of Regensburg, D-93040 Regensburg, Germany
| | - Wolfgang Seufert
- Department of Genetics, University of Regensburg, D-93040 Regensburg, Germany
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20
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Laomettachit T, Chen KC, Baumann WT, Tyson JJ. A Model of Yeast Cell-Cycle Regulation Based on a Standard Component Modeling Strategy for Protein Regulatory Networks. PLoS One 2016; 11:e0153738. [PMID: 27187804 PMCID: PMC4871373 DOI: 10.1371/journal.pone.0153738] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2015] [Accepted: 04/04/2016] [Indexed: 12/14/2022] Open
Abstract
To understand the molecular mechanisms that regulate cell cycle progression in eukaryotes, a variety of mathematical modeling approaches have been employed, ranging from Boolean networks and differential equations to stochastic simulations. Each approach has its own characteristic strengths and weaknesses. In this paper, we propose a “standard component” modeling strategy that combines advantageous features of Boolean networks, differential equations and stochastic simulations in a framework that acknowledges the typical sorts of reactions found in protein regulatory networks. Applying this strategy to a comprehensive mechanism of the budding yeast cell cycle, we illustrate the potential value of standard component modeling. The deterministic version of our model reproduces the phenotypic properties of wild-type cells and of 125 mutant strains. The stochastic version of our model reproduces the cell-to-cell variability of wild-type cells and the partial viability of the CLB2-dbΔ clb5Δ mutant strain. Our simulations show that mathematical modeling with “standard components” can capture in quantitative detail many essential properties of cell cycle control in budding yeast.
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Affiliation(s)
- Teeraphan Laomettachit
- Genetics, Bioinformatics, and Computational Biology Program, Virginia Polytechnic Institute and State University, Blacksburg, Virginia, United States of America
| | - Katherine C. Chen
- Department of Biological Sciences, Virginia Polytechnic Institute and State University, Blacksburg, Virginia, United States of America
| | - William T. Baumann
- Department of Electrical and Computer Engineering, Virginia Polytechnic Institute and State University, Blacksburg, Virginia, United States of America
| | - John J. Tyson
- Department of Biological Sciences, Virginia Polytechnic Institute and State University, Blacksburg, Virginia, United States of America
- * E-mail:
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21
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Wang H, Huang ZX, Au Yong JY, Zou H, Zeng G, Gao J, Wang Y, Wong AHH, Wang Y. CDK phosphorylates the polarisome scaffold Spa2 to maintain its localization at the site of cell growth. Mol Microbiol 2016; 101:250-64. [DOI: 10.1111/mmi.13386] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Affiliation(s)
- Haitao Wang
- Institute of Molecular and Cell Biology, Agency for Science, Technology, and Research; Singapore
- Faculty of Health Sciences; University of Macau; Macau China
| | - Zhen-Xing Huang
- Institute of Molecular and Cell Biology, Agency for Science, Technology, and Research; Singapore
| | - Jie Ying Au Yong
- Institute of Molecular and Cell Biology, Agency for Science, Technology, and Research; Singapore
| | - Hao Zou
- Institute of Molecular and Cell Biology, Agency for Science, Technology, and Research; Singapore
| | - Guisheng Zeng
- Institute of Molecular and Cell Biology, Agency for Science, Technology, and Research; Singapore
| | - Jiaxin Gao
- Institute of Molecular and Cell Biology, Agency for Science, Technology, and Research; Singapore
| | - Yanming Wang
- Institute of Molecular and Cell Biology, Agency for Science, Technology, and Research; Singapore
| | | | - Yue Wang
- Institute of Molecular and Cell Biology, Agency for Science, Technology, and Research; Singapore
- Department of Biochemistry, Yong Loo Lin School of Medicine; National University of Singapore; Singapore
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22
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Aravamudhan P, Goldfarb AA, Joglekar AP. The kinetochore encodes a mechanical switch to disrupt spindle assembly checkpoint signalling. Nat Cell Biol 2015; 17:868-79. [PMID: 26053220 PMCID: PMC4630029 DOI: 10.1038/ncb3179] [Citation(s) in RCA: 105] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2014] [Accepted: 04/23/2015] [Indexed: 12/14/2022]
Abstract
The spindle assembly checkpoint (SAC) is a unique signalling mechanism that responds to the state of attachment of the kinetochore to spindle microtubules. SAC signalling is activated by unattached kinetochores, and it is silenced after these kinetochores form end-on microtubule attachments. Although the biochemical cascade of SAC signalling is well understood, how kinetochore-microtubule attachment disrupts it remained unknown. Here we show that, in budding yeast, end-on microtubule attachment to the kinetochore physically separates the Mps1 kinase, which probably binds to the calponin homology domain of Ndc80, from the kinetochore substrate of Mps1, Spc105 (KNL1 orthologue). This attachment-mediated separation disrupts the phosphorylation of Spc105, and enables SAC silencing. Additionally, the Dam1 complex may act as a barrier that shields Spc105 from Mps1. Together these data suggest that the protein architecture of the kinetochore encodes a mechanical switch. End-on microtubule attachment to the kinetochore turns this switch off to silence the SAC.
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Affiliation(s)
| | - Alan A. Goldfarb
- Cell and developmental biology, University of Michigan, 109 Zina Pitcher Place, 3067 BSRB, Ann Arbor, MI-48109, USA
| | - Ajit P. Joglekar
- Biophysics, University of Michigan, Ann Arbor, MI-48109, USA
- Cell and developmental biology, University of Michigan, 109 Zina Pitcher Place, 3067 BSRB, Ann Arbor, MI-48109, USA
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23
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Roccuzzo M, Visintin C, Tili F, Visintin R. FEAR-mediated activation of Cdc14 is the limiting step for spindle elongation and anaphase progression. Nat Cell Biol 2015; 17:251-61. [PMID: 25706236 DOI: 10.1038/ncb3105] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2014] [Accepted: 01/09/2015] [Indexed: 01/01/2023]
Abstract
Cleavage of cohesins and cyclin-dependent kinase (CDK) inhibition are thought to be sufficient for triggering chromosome segregation. Here we identify an essential requirement for anaphase chromosome movement. We show that, at anaphase onset, the phosphatase Cdc14 and the polo-like kinase Cdc5 are redundantly required to drive spindle elongation. This role of Cdc14 is mediated by the FEAR network, a group of proteins that activates Cdc14 at anaphase onset, and we suggest that Cdc5 facilitates both Cdc14 activation and CDK inhibition. We further identify the kinesin-5 motor protein Cin8 as a key target of Cdc14. Indeed, Cin8 mutants lacking critical CDK phosphorylation sites suppress the requirement for Cdc14 and Cdc5 in anaphase spindle elongation. Our results indicate that cohesin dissolution and CDK inhibition per se are not sufficient to drive sister chromatid segregation but that the motor protein Cin8 must be activated to elongate the spindle.
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Affiliation(s)
- Michela Roccuzzo
- Department of Experimental Oncology, European Institute of Oncology, Milan 20139, Italy
| | - Clara Visintin
- Department of Experimental Oncology, European Institute of Oncology, Milan 20139, Italy
| | - Federico Tili
- Department of Experimental Oncology, European Institute of Oncology, Milan 20139, Italy
| | - Rosella Visintin
- Department of Experimental Oncology, European Institute of Oncology, Milan 20139, Italy
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24
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Su H, Wan Q, Tian XJ, He FF, Gao P, Tang H, Ye C, Fan D, Chen S, Wang YM, Meng XF, Zhang C. MAD2B contributes to podocyte injury of diabetic nephropathy via inducing cyclin B1 and Skp2 accumulation. Am J Physiol Renal Physiol 2015; 308:F728-36. [PMID: 25651564 DOI: 10.1152/ajprenal.00409.2014] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2014] [Accepted: 01/19/2015] [Indexed: 11/22/2022] Open
Abstract
It is well documented that mitotic arrest deficiency (MAD)2B can inhibit the anaphase-promoting complex/cyclosome (APC/C) via cadherin (Cdh)1 and, consequently, can destroy the effective mitotic spindle checkpoint control. Podocytes have been observed to rapidly detach and die when being forced to bypass cell cycle checkpoints. However, the role of MAD2B, a cell cycle regulator, in podocyte impairment of diabetic nephropathy (DN) is unclear. In the present study, we investigated the significance of MAD2B in the pathogenesis of DN in patients, an animal model, and in vitro podocyte cultures. By Western blot and immunohistochemistry analyses, we found that MAD2B was evidently upregulated under high glucose milieu in vivo and in vitro, whereas Cdh1 was inhibited with high glucose exposure. Overexpression of MAD2B in podocytes by plasmid DNA transfection suppressed expression of Cdh1 and triggered the accumulation of cyclin B1 and S phase kinase-associated protein (Skp)2, two key molecules involving in cell cycle regulation, and the subsequent podocyte insult. In contrast, MAD2B deletion alleviated the high glucose-induced reduction of Cdh1 as well as the elevation of cyclin B1 and Skp2, which rescued the podocyte from damage. Taken together, our data demonstrate that MAD2B may play an important role in high glucose-mediated podocyte injury of DN via modulation of Cdh1, cyclin B1, and Skp2 expression.
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Affiliation(s)
- Hua Su
- Department of Nephrology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Qiang Wan
- Department of Nephrology, Shandong Provincial Hospital Affiliated to Shandong University, Jinan, China; and
| | - Xiu-Juan Tian
- Department of Nephrology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Fang-Fang He
- Department of Nephrology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Pan Gao
- Department of Nephrology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Hui Tang
- Department of Nephrology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Chen Ye
- Department of Nephrology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Di Fan
- Department of Nephrology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Shan Chen
- Department of Nephrology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Yu-Mei Wang
- Department of Nephrology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Xian-Fang Meng
- Department of Neurobiology, School of Basic Medical Sciences, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Chun Zhang
- Department of Nephrology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China;
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25
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Lu D, Hsiao JY, Davey NE, Van Voorhis VA, Foster SA, Tang C, Morgan DO. Multiple mechanisms determine the order of APC/C substrate degradation in mitosis. ACTA ACUST UNITED AC 2014; 207:23-39. [PMID: 25287299 PMCID: PMC4195823 DOI: 10.1083/jcb.201402041] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
To ensure proper mitotic progression, robust ordering of the destruction of APC/CCdc20 substrates is driven by the integration of molecular mechanisms ranging from phosphorylation-dependent interaction with substrates to sensing of the status of the spindle assembly checkpoint. The ubiquitin protein ligase anaphase-promoting complex or cyclosome (APC/C) controls mitosis by promoting ordered degradation of securin, cyclins, and other proteins. The mechanisms underlying the timing of APC/C substrate degradation are poorly understood. We explored these mechanisms using quantitative fluorescence microscopy of GFP-tagged APC/CCdc20 substrates in living budding yeast cells. Degradation of the S cyclin, Clb5, begins early in mitosis, followed 6 min later by the degradation of securin and Dbf4. Anaphase begins when less than half of securin is degraded. The spindle assembly checkpoint delays the onset of Clb5 degradation but does not influence securin degradation. Early Clb5 degradation depends on its interaction with the Cdk1–Cks1 complex and the presence of a Cdc20-binding “ABBA motif” in its N-terminal region. The degradation of securin and Dbf4 is delayed by Cdk1-dependent phosphorylation near their Cdc20-binding sites. Thus, a remarkably diverse array of mechanisms generates robust ordering of APC/CCdc20 substrate destruction.
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Affiliation(s)
- Dan Lu
- Department of Physiology and Department of Biochemistry and Biophysics and Department of Cellular and Molecular Pharmacology, University of California, San Francisco, CA 94158
| | - Jennifer Y Hsiao
- Department of Physiology and Department of Biochemistry and Biophysics and Department of Cellular and Molecular Pharmacology, University of California, San Francisco, CA 94158
| | - Norman E Davey
- Department of Physiology and Department of Biochemistry and Biophysics and Department of Cellular and Molecular Pharmacology, University of California, San Francisco, CA 94158
| | - Vanessa A Van Voorhis
- Department of Physiology and Department of Biochemistry and Biophysics and Department of Cellular and Molecular Pharmacology, University of California, San Francisco, CA 94158
| | - Scott A Foster
- Department of Physiology and Department of Biochemistry and Biophysics and Department of Cellular and Molecular Pharmacology, University of California, San Francisco, CA 94158
| | - Chao Tang
- Center for Quantitative Biology and Peking-Tsinghua Center for Life Sciences, Peking University, Beijing 100871, China
| | - David O Morgan
- Department of Physiology and Department of Biochemistry and Biophysics and Department of Cellular and Molecular Pharmacology, University of California, San Francisco, CA 94158
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26
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Li J, Gao JZ, Du JL, Huang ZX, Wei LX. Increased CDC20 expression is associated with development and progression of hepatocellular carcinoma. Int J Oncol 2014; 45:1547-55. [PMID: 25069850 DOI: 10.3892/ijo.2014.2559] [Citation(s) in RCA: 108] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2014] [Accepted: 04/22/2014] [Indexed: 11/05/2022] Open
Abstract
Cell division cycle 20 (CDC20) encodes a regulatory protein interacting with the anaphase-promoting complex/cyclosome (APC/C) in the cell cycle and plays important roles in tumorigenesis and progression of multiple tumors. The present study aimed to investigate the clinical significance of CDC20 in hepatocellular carcinoma (HCC) and the role of CDC20 in the progression of HCC. By bioinformatics analysis, CDC20 was found to be the major node in HCC molecular interaction networks. Quantitative PCR and western blot analyses were applied to examine CDC20 expression in 16 paired primary HCC tissues. Immunohistochemistry (IHC) was performed to examine CDC20 protein expression in 132 matched paraffin-embedded HCC tissues and to analyze the relationship between CDC20 staining and clinical characteristics. Small interfering RNA (siRNA) targeting CDC20 was synthesized and transfected into HepG2 cells to investigate the role of CDC20 in cell growth and the cell cycle. Results show that CDC20 expression was upregulated in HCC tissues compared to adjacent non-tumor liver tissues. In the 132 matched HCC tissues, high expression levels of CDC20 were detected in 68.18% HCC samples, and overexpression of CDC20 was positively correlated with gender (P=0.013), tumor differentiation (P=0.000), TNM stage (P=0.012), P53 and Ki-67 expression (P=0.023 and P=0.007, respectively). Cells transfected with CDC20 siRNA showed a decrease in cell proliferation and increase in the number of cells in G2/M-phase. In conclusion, increased expression of CDC20 was demonstrated to be associated with the development and progression of HCC, and may be regarded as a promising therapeutic target for HCC.
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Affiliation(s)
- Jia Li
- Department of Pathology, Chinese PLA General Hospital, Beijing 100853, P.R. China
| | - Jian-Zhi Gao
- Department of Pathology, Chinese PLA General Hospital, Beijing 100853, P.R. China
| | - Jing-Li Du
- Department of Pathology, Chinese PLA General Hospital, Beijing 100853, P.R. China
| | - Zhong-Xi Huang
- Cancer Institute, Southern Medical University, Guangzhou, Guangdong 510515, P.R. China
| | - Li-Xin Wei
- Department of Pathology, Chinese PLA General Hospital, Beijing 100853, P.R. China
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27
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Lianga N, Williams EC, Kennedy EK, Doré C, Pilon S, Girard SL, Deneault JS, Rudner AD. A Wee1 checkpoint inhibits anaphase onset. ACTA ACUST UNITED AC 2013; 201:843-62. [PMID: 23751495 PMCID: PMC3678162 DOI: 10.1083/jcb.201212038] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
The budding yeast Wee1 kinase Swe1 restrains the metaphase-to-anaphase transition by preventing the Cdk1-dependent phosphorylation and activation of APCCdc20. Cdk1 drives both mitotic entry and the metaphase-to-anaphase transition. Past work has shown that Wee1 inhibition of Cdk1 blocks mitotic entry. Here we show that the budding yeast Wee1 kinase, Swe1, also restrains the metaphase-to-anaphase transition by preventing Cdk1 phosphorylation and activation of the mitotic form of the anaphase-promoting complex/cyclosome (APCCdc20). Deletion of SWE1 or its opposing phosphatase MIH1 (the budding yeast cdc25+) altered the timing of anaphase onset, and activation of the Swe1-dependent morphogenesis checkpoint or overexpression of Swe1 blocked cells in metaphase with reduced APC activity in vivo and in vitro. The morphogenesis checkpoint also depended on Cdc55, a regulatory subunit of protein phosphatase 2A (PP2A). cdc55Δ checkpoint defects were rescued by mutating 12 Cdk1 phosphorylation sites on the APC, demonstrating that the APC is a target of this checkpoint. These data suggest a model in which stepwise activation of Cdk1 and inhibition of PP2ACdc55 triggers anaphase onset.
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Affiliation(s)
- Noel Lianga
- Ottawa Institute of Systems Biology and Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, Ontario K1H 8M5, Canada
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28
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Koltovaya NA. Involvement of cyclin-dependent kinase CDK1/CDC28 in regulation of cell cycle. RUSS J GENET+ 2013. [DOI: 10.1134/s1022795413050086] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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29
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Abstract
Productive cell proliferation involves efficient and accurate splitting of the dividing cell into two separate entities. This orderly process reflects coordination of diverse cytological events by regulatory systems that drive the cell from mitosis into G1. In the budding yeast Saccharomyces cerevisiae, separation of mother and daughter cells involves coordinated actomyosin ring contraction and septum synthesis, followed by septum destruction. These events occur in precise and rapid sequence once chromosomes are segregated and are linked with spindle organization and mitotic progress by intricate cell cycle control machinery. Additionally, critical paarts of the mother/daughter separation process are asymmetric, reflecting a form of fate specification that occurs in every cell division. This chapter describes central events of budding yeast cell separation, as well as the control pathways that integrate them and link them with the cell cycle.
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Khong JH, Zhang T, Gunaratne J, Blackstock W, Surana U. "Reductional anaphase" in replication-defective cells is caused by ubiquitin-conjugating enzyme Cdc34-mediated deregulation of the spindle. Cell Cycle 2012; 11:2896-910. [PMID: 22805765 DOI: 10.4161/cc.21303] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Equal partitioning of the duplicated chromosomes into two daughter cells during cell division is a coordinated process and is initiated only after completion of DNA synthesis. However, this strict order of execution breaks down in CDC6-deficient cells. Cdc6, an evolutionarily conserved protein, is required for the assembly of pre-replicative complexes (pre-RCs) and is essential for the initiation of DNA replication. Yeast cells lacking Cdc6 function, though unable to initiate DNA replication, proceed to undergo "reductional anaphase" by partitioning the unreplicated chromosomes and lose viability rapidly. This extreme form of genomic instability in cdc6 cells is thought to be due to inactivation of a pre-RC based, Cdc6-dependent checkpoint mechanism that, during normal cell cycle, inhibits premature onset of mitosis until pre-RC is assembled. Here, we show that chromosome segregation in cdc6 mutant is caused not by precocious initiation of mitosis in the absence of a checkpoint, but by the deregulation of spindle dynamics induced via a regulatory network involving the ubiquitin-conjugating enzyme Cdc34, microtubule-associated proteins (MAPs) and the anaphase-promoting complex (APC) activator Cdh1. This regulatory circuit governs spindle behavior in the early part of the division cycle and precipitates catastrophic chromosome segregation in the absence of DNA replication.
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Affiliation(s)
- Jenn Hui Khong
- Institute of Molecular and Cell Biology, A*STAR (Agency for Science, Technology and Research), Singapore
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Regulation of APC/C-Cdh1 and its function in neuronal survival. Mol Neurobiol 2012; 46:547-54. [PMID: 22836916 PMCID: PMC3496556 DOI: 10.1007/s12035-012-8309-2] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2012] [Accepted: 07/12/2012] [Indexed: 12/22/2022]
Abstract
Neurons are post-mitotic cells that undergo an active downregulation of cell cycle-related proteins to survive. The activity of the anaphase-promoting complex/cyclosome (APC/C), an E3 ubiquitin ligase that regulates cell cycle progression in proliferating cells, plays a relevant role in post-mitotic neurons. Recent advances in the study of the regulation of APC/C have documented that the APC/C-activating cofactor, Cdh1, is essential for the function(s) of APC/C in neuronal survival. Here, we review the normal regulation of APC/C activity in proliferating cells and neurons. We conclude that in neurons the APC/C-Cdh1 complex actively downregulates the stability of the cell cycle protein cyclin B1 and the glycolytic enzyme 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase-3. Keeping these proteins destabilized is critical both for preventing the aberrant reentry of post-mitotic neurons into the cell cycle and for maintaining their reduced antioxidant status. Further understanding of the pathophysiological regulation of these proteins by APC/C-Cdh1 in neurons will be important for the search for novel therapeutic targets against neurodegeneration.
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Kato T, Daigo Y, Aragaki M, Ishikawa K, Sato M, Kaji M. Overexpression of CDC20 predicts poor prognosis in primary non-small cell lung cancer patients. J Surg Oncol 2012; 106:423-30. [DOI: 10.1002/jso.23109] [Citation(s) in RCA: 110] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2012] [Accepted: 03/06/2012] [Indexed: 01/29/2023]
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Hancioglu B, Tyson JJ. A mathematical model of mitotic exit in budding yeast: the role of Polo kinase. PLoS One 2012; 7:e30810. [PMID: 22383977 PMCID: PMC3285609 DOI: 10.1371/journal.pone.0030810] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2011] [Accepted: 12/21/2011] [Indexed: 12/20/2022] Open
Abstract
Cell cycle progression in eukaryotes is regulated by periodic activation and inactivation of a family of cyclin-dependent kinases (Cdk's). Entry into mitosis requires phosphorylation of many proteins targeted by mitotic Cdk, and exit from mitosis requires proteolysis of mitotic cyclins and dephosphorylation of their targeted proteins. Mitotic exit in budding yeast is known to involve the interplay of mitotic kinases (Cdk and Polo kinases) and phosphatases (Cdc55/PP2A and Cdc14), as well as the action of the anaphase promoting complex (APC) in degrading specific proteins in anaphase and telophase. To understand the intricacies of this mechanism, we propose a mathematical model for the molecular events during mitotic exit in budding yeast. The model captures the dynamics of this network in wild-type yeast cells and 110 mutant strains. The model clarifies the roles of Polo-like kinase (Cdc5) in the Cdc14 early anaphase release pathway and in the G-protein regulated mitotic exit network.
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Affiliation(s)
- Baris Hancioglu
- Department of Biological Sciences, Virginia Polytechnic Institute and State University, Blacksburg, Virginia, United States of America.
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Martinez JS, Hall H, Bartolowits MD, Hall MC. Acm1 contributes to nuclear positioning by inhibiting Cdh1-substrate interactions. Cell Cycle 2012; 11:384-94. [PMID: 22189709 DOI: 10.4161/cc.11.2.18944] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
The anaphase-promoting complex (APC) is tightly regulated during cell division, often by pseudosubstrate binding to its coactivators Cdh1 and Cdc20. Budding yeast Acm1 is a Cdh1 pseudosubstrate inhibitor whose biological function is unknown. We show here that cells lacking Acm1 have defects in nuclear positioning and spindle morphology during mitosis. However, Cdh1 substrates are not destabilized in the absence of Acm1 and expression of inactive Cdh1 mutants that retain substrate binding is sufficient for the acm1 phenotype. We conclude that Acm1 is not required to inhibit APC(Cdh1) activity but rather prevents untimely Cdh1-substrate interactions. We further provide evidence suggesting that the substrate primarily responsible for the acm1 phenotype is the bud neck-localized kinase, Hsl1. Our results imply that at least some coactivator-substrate interactions require regulation. Several unrelated APC pseudosubstrates have been identified in diverse eukaryotes and their ability to simultaneously inhibit enzymatic activity and substrate binding may partly explain why this regulatory mechanism has been selected repeatedly during evolution.
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Affiliation(s)
- Juan S Martinez
- Department of Biochemistry and Center for Cancer Research, Purdue University, West Lafayette, IN, USA
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Chin CF, Bennett AM, Ma WK, Hall MC, Yeong FM. Dependence of Chs2 ER export on dephosphorylation by cytoplasmic Cdc14 ensures that septum formation follows mitosis. Mol Biol Cell 2011; 23:45-58. [PMID: 22072794 PMCID: PMC3248903 DOI: 10.1091/mbc.e11-05-0434] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Sequestration of Cdc14 from the cytoplasm ensures Chs2 ER retention after MEN activation. The interdependence of chromosome segregation, MEN activation, decrease in mitotic CDK activity, and Cdc14 dispersal provides an effective mechanism for cells to order late mitotic events. Cytokinesis, which leads to the physical separation of two dividing cells, is normally restrained until after nuclear division. In Saccharomyces cerevisiae, chitin synthase 2 (Chs2), which lays down the primary septum at the mother–daughter neck, also ensures proper actomyosin ring constriction during cytokinesis. During the metaphase-to-anaphase transition, phosphorylation of Chs2 by the mitotic cyclin-dependent kinase (Cdk1) retains Chs2 at the endoplasmic reticulum (ER), thereby preventing its translocation to the neck. Upon Cdk1 inactivation at the end of mitosis, Chs2 is exported from the ER and targeted to the neck. The mechanism for triggering Chs2 ER export thus far is unknown. We show here that Chs2 ER export requires the direct reversal of the inhibitory Cdk1 phosphorylation sites by Cdc14 phosphatase, the ultimate effector of the mitotic exit network (MEN). We further show that only Cdc14 liberated by the MEN after completion of chromosome segregation, and not Cdc14 released in early anaphase by the Cdc fourteen early anaphase release pathway, triggers Chs2 ER exit. Presumably, the reduced Cdk1 activity in late mitosis further favors dephosphorylation of Chs2 by Cdc14. Thus, by requiring declining Cdk1 activity and Cdc14 nuclear release for Chs2 ER export, cells ensure that septum formation is contingent upon chromosome separation and exit from mitosis.
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Affiliation(s)
- Cheen Fei Chin
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
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Cdk1 promotes kinetochore bi-orientation and regulates Cdc20 expression during recovery from spindle checkpoint arrest. EMBO J 2011; 31:403-16. [PMID: 22056777 DOI: 10.1038/emboj.2011.385] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2011] [Accepted: 10/02/2011] [Indexed: 11/08/2022] Open
Abstract
The spindle assembly checkpoint (SAC), an evolutionarily conserved surveillance pathway, prevents chromosome segregation in response to conditions that disrupt the kinetochore-microtubule attachment. Removal of the checkpoint-activating stimulus initiates recovery during which spindle integrity is restored, kinetochores become bi-oriented, and cells initiate anaphase. Whether recovery ensues passively after the removal of checkpoint stimulus, or requires mediation by specific effectors remains uncertain. Here, we report two unrecognized functions of yeast Cdk1 required for efficient recovery from SAC-induced arrest. We show that Cdk1 promotes kinetochore bi-orientation during recovery by restraining premature spindle elongation thereby extinguishing SAC signalling. Moreover, Cdk1 is essential for sustaining the expression of Cdc20, an activator of the anaphase promoting complex/cyclosome (APC/C) required for anaphase progression. We suggest a model in which Cdk1 activity promotes recovery from SAC-induced mitotic arrest by regulating bi-orientation and APC/C activity. Our findings provide fresh insights into the regulation of mitosis and have implications for the therapeutic efficacy of anti-mitotic drugs.
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Wurzenberger C, Gerlich DW. Phosphatases: providing safe passage through mitotic exit. Nat Rev Mol Cell Biol 2011; 12:469-82. [PMID: 21750572 DOI: 10.1038/nrm3149] [Citation(s) in RCA: 236] [Impact Index Per Article: 18.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
The mitosis-to-interphase transition involves dramatic cellular reorganization from a state that supports chromosome segregation to a state that complies with all functions of an interphase cell. This process, termed mitotic exit, depends on the removal of mitotic phosphorylations from a broad range of substrates. Mitotic exit regulation involves inactivation of mitotic kinases and activation of counteracting protein phosphatases. The key mitotic exit phosphatase in budding yeast, Cdc14, is now well understood. By contrast, in animal cells, it is now emerging that mitotic exit relies on distinct regulatory networks, including the protein phosphatases PP1 and PP2A.
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Affiliation(s)
- Claudia Wurzenberger
- Institute of Biochemistry, Department of Biology, Swiss Federal Institute of Technology Zürich (ETHZ), HPM D11.3, Schafmattstrasse 18, 8093 Zürich, Switzerland
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A model of yeast cell-cycle regulation based on multisite phosphorylation. Mol Syst Biol 2011; 6:405. [PMID: 20739927 PMCID: PMC2947364 DOI: 10.1038/msb.2010.55] [Citation(s) in RCA: 93] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2009] [Accepted: 06/20/2010] [Indexed: 12/12/2022] Open
Abstract
In order for the cell's genome to be passed intact from one generation to the next, the events of the cell cycle (DNA replication, mitosis, cell division) must be executed in the correct order, despite the considerable molecular noise inherent in any protein-based regulatory system residing in the small confines of a eukaryotic cell. To assess the effects of molecular fluctuations on cell-cycle progression in budding yeast cells, we have constructed a new model of the regulation of Cln- and Clb-dependent kinases, based on multisite phosphorylation of their target proteins and on positive and negative feedback loops involving the kinases themselves. To account for the significant role of noise in the transcription and translation steps of gene expression, the model includes mRNAs as well as proteins. The model equations are simulated deterministically and stochastically to reveal the bistable switching behavior on which proper cell-cycle progression depends and to show that this behavior is robust to the level of molecular noise expected in yeast-sized cells (approximately 50 fL volume). The model gives a quantitatively accurate account of the variability observed in the G1-S transition in budding yeast, which is governed by an underlying sizer+timer control system.
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Ball DA, Ahn TH, Wang P, Chen KC, Cao Y, Tyson JJ, Peccoud J, Baumann WT. Stochastic exit from mitosis in budding yeast: model predictions and experimental observations. Cell Cycle 2011; 10:999-1009. [PMID: 21350333 PMCID: PMC3100879 DOI: 10.4161/cc.10.6.14966] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2010] [Revised: 01/27/2011] [Accepted: 01/27/2011] [Indexed: 11/19/2022] Open
Abstract
Unlike many mutants that are completely viable or inviable, the CLB2-dbΔ clb5Δ mutant of Saccharomyces cerevisiae is inviable in glucose but partially viable on slower growth media such as raffinose. On raffinose, the mutant cells can bud and divide but in each cycle there is a chance that a cell will fail to divide (telophase arrest), causing it to exit the cell cycle. This effect gives rise to a stochastic phenotype that cannot be explained by a deterministic model. We measure the inter-bud times of wild type and mutant cells growing on raffinose and compute statistics and distributions to characterize the mutant's behavior. We convert a detailed deterministic model of the budding yeast cell cycle to a stochastic model and determine the extent to which it captures the stochastic phenotype of the mutant strain. Predictions of the mathematical model are in reasonable agreement with our experimental data and suggest directions for improving the model. Ultimately, the ability to accurately model stochastic phenotypes may prove critical to understanding disease and therapeutic interventions in higher eukaryotes.
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Affiliation(s)
- David A Ball
- Virginia Polytechnic Institute and State University, Blacksburg, VA, USA
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Orthologues of the anaphase-promoting complex/cyclosome coactivators Cdc20p and Cdh1p are important for mitotic progression and morphogenesis in Candida albicans. EUKARYOTIC CELL 2011; 10:696-709. [PMID: 21398510 DOI: 10.1128/ec.00263-10] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
The conserved anaphase-promoting complex/cyclosome (APC/C) system mediates protein degradation during mitotic progression. Conserved coactivators Cdc20p and Cdh1p regulate the APC/C during early to late mitosis and G(1) phase. Candida albicans is an important fungal pathogen of humans, and it forms highly polarized cells when mitosis is blocked through depletion of the polo-like kinase Cdc5p or other treatments. However, the mechanisms governing mitotic progression and associated polarized growth in the pathogen are poorly understood. In order to gain insights into these processes, we characterized C. albicans orthologues of Cdc20p and Cdh1p. Cdc20p-depleted cells were blocked in early or late mitosis with elevated levels of Cdc5p and the mitotic cyclin Clb2p, suggesting that Cdc20p is essential and has some conserved functions during mitosis. However, the yeast cells formed highly polarized buds in contrast to the large doublets of S. cerevisiae cdc20 mutants, implying a distinct role in morphogenesis. In comparison, cdh1Δ/cdh1Δ cells were viable but showed enrichment of Clb2p and Cdc5p, suggesting that Cdh1p may influence mitotic exit. The cdh1Δ/cdh1Δ phenotype was pleiotropic, consisting of normal or enlarged yeast, pseudohyphae, and some elongated buds, whereas S. cerevisiae cdh1Δ yeast cells were reduced in size. Thus, C. albicans Cdh1p may have some distinct functions. Finally, absence of Cdh1p or Cdc20p had a minor or no effect on hyphal development, respectively. Overall, the results suggest that Cdc20p and Cdh1p may be APC/C activators that are important for mitosis but also morphogenesis in C. albicans. Their novel features imply additional variations in function and underscore rewiring in the emerging mitotic regulatory networks of the pathogen.
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Vinod PK, Freire P, Rattani A, Ciliberto A, Uhlmann F, Novak B. Computational modelling of mitotic exit in budding yeast: the role of separase and Cdc14 endocycles. J R Soc Interface 2011; 8:1128-41. [PMID: 21288956 DOI: 10.1098/rsif.2010.0649] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
The operating principles of complex regulatory networks are best understood with the help of mathematical modelling rather than by intuitive reasoning. Hereby, we study the dynamics of the mitotic exit (ME) control system in budding yeast by further developing the Queralt's model. A comprehensive systems view of the network regulating ME is provided based on classical experiments in the literature. In this picture, Cdc20-APC is a critical node controlling both cyclin (Clb2 and Clb5) and phosphatase (Cdc14) branches of the regulatory network. On the basis of experimental situations ranging from single to quintuple mutants, the kinetic parameters of the network are estimated. Numerical analysis of the model quantifies the dependence of ME control on the proteolytic and non-proteolytic functions of separase. We show that the requirement of the non-proteolytic function of separase for ME depends on cyclin-dependent kinase activity. The model is also used for the systematic analysis of the recently discovered Cdc14 endocycles. The significance of Cdc14 endocycles in eukaryotic cell cycle control is discussed as well.
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Affiliation(s)
- P K Vinod
- Department of Biochemistry, Oxford Centre for Integrative Systems Biology, University of Oxford, South Parks Road, Oxford OX1 3QU, UK
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Abstract
Alternation of chromosome replication and segregation is essential for successful completion of the cell cycle and it requires an oscillation of Cdk1 (cyclin-dependent kinase 1)-CycB (cyclin B) activity. In the present review, we illustrate the essential features of checkpoint controlled and uncontrolled cell-cycle oscillations by using mechanical metaphors. Despite variations in the molecular details of the oscillatory mechanism, the underlying network motifs responsible for the oscillations are always well-conserved. The checkpoint-controlled cell cycles are always driven by a negative-feedback loop amplified by double-negative feedbacks (antagonism).
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Robbins JA, Cross FR. Regulated degradation of the APC coactivator Cdc20. Cell Div 2010; 5:23. [PMID: 20831816 PMCID: PMC2949745 DOI: 10.1186/1747-1028-5-23] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2010] [Accepted: 09/10/2010] [Indexed: 12/23/2022] Open
Abstract
Background Cdc20 is a highly conserved activator of the anaphase-promoting complex (APC), promoting cell-cycle-regulated ubiquitination and proteolysis of a number of critical cell-cycle-regulatory targets including securin and mitotic cyclins. APC-Cdc20 activity is tightly regulated, and this regulation is likely important for accurate cell cycle control. One significant component of Cdc20 regulation is thought to be Cdc20 proteolysis. However, published literature suggests different mechanisms and requirements for Cdc20 proteolysis. The degree to which Cdc20 proteolysis is cell-cycle regulated, the dependence of Cdc20 proteolysis on Cdc20 destruction boxes (recognition sequences for APC-mediated ubiqutination, either by Cdc20 or by the related Cdh1 APC activator), and the need for APC itself for Cdc20 proteolysis all have been disputed to varying extents. In animals, Cdc20 proteolysis is thought to be mediated by Cdh1, contributing an intrinsic order of APC activation by Cdc20 and then by Cdh1. One report suggests a Cdh1 requirement for Cdc20 proteolysis in budding yeast; this idea has not been tested further. Results We characterized Cdc20 proteolysis using Cdc20 expressed from its endogenous locus; previous studies generally employed strongly overexpressed Cdc20, which can cause significant artifacts. We analyzed Cdc20 proteolysis with or without mutations in previously identified destruction box sequences, using varying methods of cell cycle synchronization, and in the presence or absence of Cdh1. Cdc20 instability is only partially dependent on destruction boxes. A much stronger dependence on Cdh1 for Cdc20 proteolysis was observed, but Cdh1-independent proteolysis was also clearly observed. Cdc20 proteolysis independent of both destruction boxes and Cdh1 was especially detectable around the G1/S transition; Cdh1-dependent proteolysis was most notable in late mitosis and G1. Conclusions Cdc20 proteolysis is under complex control, with different systems operating at different points in the cell cycle. This complexity is likely to explain apparent conflicts in previously published literature on this subject. A major mode of control of Cdc20 proteolysis occurs in late mitosis/early G1 and is Cdh1-dependent, as in animal cells; this mode may contribute to the known sequential activation of the APC by Cdc20 followed by Cdh1. An independent mode of Cdc20 proteolysis, independent of destruction boxes and Cdh1, occurs at G1/S; we do not know the mechanism or function of this mode of proteolysis, but speculate that it may contribute to sharpening and restricting activation of APC-Cdc20 to early mitosis.
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Affiliation(s)
- Jonathan A Robbins
- Laboratory of Yeast Molecular Genetics, The Rockefeller University, New York, NY, USA.
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Lu Y, Cross FR. Periodic cyclin-Cdk activity entrains an autonomous Cdc14 release oscillator. Cell 2010; 141:268-79. [PMID: 20403323 DOI: 10.1016/j.cell.2010.03.021] [Citation(s) in RCA: 74] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2009] [Revised: 12/24/2009] [Accepted: 03/17/2010] [Indexed: 12/22/2022]
Abstract
One oscillation of Cyclin-dependent kinase (Cdk) activity, largely driven by periodic synthesis and destruction of cyclins, is tightly coupled to a single complete eukaryotic cell division cycle. Tight linkage of different steps in diverse cell-cycle processes to Cdk activity has been proposed to explain this coupling. Here, we demonstrate an intrinsically oscillatory module controlling nucleolar release and resequestration of the Cdc14 phosphatase, which is essential for mitotic exit in budding yeast. We find that this Cdc14 release oscillator functions at constant and physiological cyclin-Cdk levels, and is therefore independent of the Cdk oscillator. However, the frequency of the release oscillator is regulated by cyclin-Cdk activity. This observation together with its mechanism suggests that the intrinsically autonomous Cdc14 release cycles are locked at once-per-cell-cycle through entrainment by the Cdk oscillator in wild-type cells. This concept may have broad implications for the structure and evolution of eukaryotic cell-cycle control.
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Affiliation(s)
- Ying Lu
- The Rockefeller University, 1230 York Avenue, New York, New York 10065, USA
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45
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Adenovirus protein E4orf4 induces premature APCCdc20 activation in Saccharomyces cerevisiae by a protein phosphatase 2A-dependent mechanism. J Virol 2010; 84:4798-809. [PMID: 20164229 DOI: 10.1128/jvi.02434-09] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Protein phosphatase 2A (PP2A) has been implicated in cell cycle progression and mitosis; however, the complexity of PP2A regulation via multiple B subunits makes its functional characterization a significant challenge. The human adenovirus protein E4orf4 has been found to induce both high Cdk1 activity and the accumulation of cells in G(2)/M in both mammalian and yeast cells, effects which are largely dependent on the B55/Cdc55 regulatory subunit of PP2A. Thus, E4orf4 represents a unique means by which the function of a specific form of PP2A can be delineated in vivo. In Saccharomyces cerevisiae, only two PP2A regulatory subunits exist, Cdc55 and Rts1. Here, we show that E4orf4-induced toxicity depends on a functional interaction with Cdc55. E4orf4 expression correlates with the inappropriate reduction of Pds1 and Scc1 in S-phase-arrested cells. The unscheduled loss of these proteins suggests the involvement of PP2A(Cdc55) in the regulation of the Cdc20 form of the anaphase-promoting complex (APC). Contrastingly, activity of the Hct1 form of the APC is not induced by E4orf4, as demonstrated by the observed stability of its substrates. We propose that E4orf4, being a Cdc55-specific inhibitor of PP2A, demonstrates the role of PP2A(Cdc55) in regulating APC(Cdc20) activity.
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König C, Maekawa H, Schiebel E. Mutual regulation of cyclin-dependent kinase and the mitotic exit network. ACTA ACUST UNITED AC 2010; 188:351-68. [PMID: 20123997 PMCID: PMC2819678 DOI: 10.1083/jcb.200911128] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
The mitotic exit network (MEN) is a spindle pole body (SPB)-associated, GTPase-driven signaling cascade that controls mitotic exit. The inhibitory Bfa1-Bub2 GTPase-activating protein (GAP) only associates with the daughter SPB (dSPB), raising the question as to how the MEN is regulated on the mother SPB (mSPB). Here, we show mutual regulation of cyclin-dependent kinase 1 (Cdk1) and the MEN. In early anaphase Cdk1 becomes recruited to the mSPB depending on the activity of the MEN kinase Cdc15. Conversely, Cdk1 negatively regulates binding of Cdc15 to the mSPB. In addition, Cdk1 phosphorylates the Mob1 protein to inhibit the activity of Dbf2-Mob1 kinase that regulates Cdc14 phosphatase. Our data revise the understanding of the spatial regulation of the MEN. Although MEN activity in the daughter cells is controlled by Bfa1-Bub2, Cdk1 inhibits MEN activity at the mSPB. Consistent with this model, only triple mutants that lack BUB2 and the Cdk1 phosphorylation sites in Mob1 and Cdc15 show mitotic exit defects.
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Affiliation(s)
- Cornelia König
- Zentrum für Molekulare Biologie der Universität Heidelberg (ZMBH), ZMBH-DKFZ Alliance, 69120 Heidelberg, Germany
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Analysis of the mitotic exit control system using locked levels of stable mitotic cyclin. Mol Syst Biol 2009; 5:328. [PMID: 19920813 PMCID: PMC2795472 DOI: 10.1038/msb.2009.78] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2009] [Accepted: 09/25/2009] [Indexed: 12/14/2022] Open
Abstract
Cyclin-dependent kinase (Cdk) both promotes mitotic entry (spindle assembly and anaphase) and inhibits mitotic exit (spindle disassembly and cytokinesis), leading to an elegant quantitative hypothesis that a single cyclin oscillation can function as a ratchet to order these events. This ratchet is at the core of a published ODE model for the yeast cell cycle. However, the ratchet model requires appropriate cyclin dose-response thresholds. Here, we test the inhibition of mitotic exit in budding yeast using graded levels of stable mitotic cyclin (Clb2). In opposition to the ratchet model, stable levels of Clb2 introduced dose-dependent delays, rather than hard thresholds, that varied by mitotic exit event. The ensuing cell cycle was highly abnormal, suggesting a novel reason for cyclin degradation. Cdc14 phosphatase antagonizes Clb2-Cdk, and Cdc14 is released from inhibitory nucleolar sequestration independently of stable Clb2. Thus, Cdc14/Clb2 balance may be the appropriate variable for mitotic regulation. Although our results are inconsistent with the aforementioned ODE model, revision of the model to allow Cdc14/Clb2 balance to control mitotic exit corrects these discrepancies, providing theoretical support for our conclusions.
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Khmelinskii A, Roostalu J, Roque H, Antony C, Schiebel E. Phosphorylation-dependent protein interactions at the spindle midzone mediate cell cycle regulation of spindle elongation. Dev Cell 2009; 17:244-56. [PMID: 19686685 DOI: 10.1016/j.devcel.2009.06.011] [Citation(s) in RCA: 88] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2009] [Revised: 04/14/2009] [Accepted: 06/19/2009] [Indexed: 12/28/2022]
Abstract
The metaphase-to-anaphase transition is one of the most dramatic and highly regulated steps in cell division. At anaphase onset the protease separase dissolves sister chromatid cohesion. Simultaneously, the mitotic spindle elongates as interpolar microtubules (iMTs) slide apart at the spindle midzone, ensuring chromosome segregation. However, it remains unclear how spindle elongation is coordinated with cell cycle progression. Here we demonstrate that phosphorylation of the midzone organizer Ase1 controls localization and function of Cin8, a kinesin-5 that slides iMTs relative to each other. Phosphorylation of Ase1 by Cdk1 (cyclin-dependent kinase) inhibits Cin8 binding to iMTs, preventing bending and collapse of the metaphase spindle. In anaphase Ase1 dephosphorylation by the separase-activated phosphatase Cdc14 is necessary and sufficient for Cin8 recruitment to the midzone, where it drives spindle elongation. Our results reveal that sliding forces at the midzone are activated by separase and explain how spindle elongation is triggered with anaphase entry.
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Affiliation(s)
- Anton Khmelinskii
- Zentrum für Molekulare Biologie der Universität Heidelberg, DKFZ-ZMBH Allianz, Im Neuenheiemer Feld 282, Heidelberg 69117, Germany
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Wäsch R, Robbins JA, Cross FR. The emerging role of APC/CCdh1 in controlling differentiation, genomic stability and tumor suppression. Oncogene 2009; 29:1-10. [PMID: 19826416 DOI: 10.1038/onc.2009.325] [Citation(s) in RCA: 87] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Deregulation of the G1/G0 phase of the cell cycle can lead to cancer. During G1, most cells commit alternatively to DNA replication and division, or to cell-cycle exit and differentiation. The anaphase-promoting complex or cyclosome (APC/C) activated by Cdh1 coordinately eliminates positive cell-cycle regulators as well as inhibitors of differentiation, thereby coupling cell-cycle exit and differentiation. Misregulation of Cdh1 thus has the potential to promote both cell-cycle re-entry and either perturbed differentiation or dedifferentiation. In addition, APC/C(Cdh1) is required to maintain genomic stability. As a result, loss of Cdh1 can contribute to tumorigenesis in the form of proliferation of poorly differentiated and genetically unstable cells.
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Affiliation(s)
- R Wäsch
- Department of Hematology and Oncology, University Medical Center, Freiburg, Germany.
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50
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Zhang T, Nirantar S, Lim HH, Sinha I, Surana U. DNA damage checkpoint maintains CDH1 in an active state to inhibit anaphase progression. Dev Cell 2009; 17:541-51. [PMID: 19853567 DOI: 10.1016/j.devcel.2009.09.006] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2008] [Revised: 02/20/2009] [Accepted: 09/18/2009] [Indexed: 01/11/2023]
Abstract
DNA damage checkpoint prevents segregation of damaged chromosomes by imposing cell-cycle arrest. In budding yeast, Mec1, Chk1, and Rad53 (homologous to human ATM/ATR, Chk1, and Chk2 kinases, respectively) are among the main effectors of this pathway. The DNA damage checkpoint is thought to inhibit chromosome segregation by preventing separase-mediated cleavage of cohesins. Here, we describe a regulatory network that prevents segregation of damaged chromosomes by restricting spindle elongation and acts in parallel with inhibition of cohesin cleavage. This control circuit involves Rad53, polo kinase, the anaphase-promoting complex activator Cdh1, and the bimC kinesin family proteins Cin8 and Kip1. The inhibition of polo kinase by Rad53-dependent phosphorylation prevents it from inactivating Cdh1. As a result, Cdh1 remains in a partially active state and limits Cin8 and Kip1 accumulation, thereby restraining spindle elongation. Hence, the DNA damage checkpoint suppresses both cohesin cleavage and spindle elongation to preserve chromosome stability.
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Affiliation(s)
- Tao Zhang
- Institute of Molecular and Cell Biology, A*STAR (Agency for Science, Technology and Research) 61, Biopolis Drive, Proteos, Singapore 138673
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