1
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Som S, Paul R. Mechanistic model for nuclear migration in hyphae during mitosis. Phys Rev E 2023; 108:014401. [PMID: 37583222 DOI: 10.1103/physreve.108.014401] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2023] [Accepted: 06/13/2023] [Indexed: 08/17/2023]
Abstract
Saccharomyces cerevisiae and Candida albicans, the two well-known human pathogens, can be found in all three morphologies, i.e., yeast, pseudohyphae, and true hyphae. The cylindrical daughter-bud (germ tube) grows very long for true hyphae, and the cell cycle is delayed compared to the other two morphologies. The place of the nuclear division is specific for true hyphae determined by the position of the septin ring. However, the septin ring can localize anywhere inside the germ tube, unlike the mother-bud junction in budding yeast. Since the nucleus often migrates a long path in the hyphae, the underlying mechanism must be robust for executing mitosis in a timely manner. We explore the mechanism of nuclear migration through hyphae in light of mechanical interactions between astral microtubules and the cell cortex. We report that proper migration through constricted hyphae requires a large dynein pull applied on the astral microtubules from the hyphal cortex. This is achieved when the microtubules frequently slide along the hyphal cortex so that a large population of dyneins actively participate, pulling on them. Simulation shows timely migration when the dyneins from the mother cortex do not participate in pulling on the microtubules. These findings are robust for long migration and positioning of the nucleus in the germ tube at the septin ring.
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Affiliation(s)
- Subhendu Som
- Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700032, India
| | - Raja Paul
- Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700032, India
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2
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Ecklund KH, Bailey ME, Kossen KA, Dietvorst CK, Asbury CL, Markus SM. The microtubule-associated protein She1 coordinates directional spindle positioning by spatially restricting dynein activity. J Cell Sci 2021; 134:273583. [PMID: 34854468 DOI: 10.1242/jcs.258510] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2021] [Accepted: 10/27/2021] [Indexed: 11/20/2022] Open
Abstract
Dynein motors move the mitotic spindle to the cell division plane in many cell types, including in budding yeast, in which dynein is assisted by numerous factors including the microtubule-associated protein (MAP) She1. Evidence suggests that She1 plays a role in polarizing dynein-mediated spindle movements toward the daughter cell; however, how She1 performs this function is unknown. We find that She1 assists dynein in maintaining the spindle in close proximity to the bud neck, such that, at anaphase onset, the chromosomes are segregated to mother and daughter cells. She1 does so by attenuating the initiation of dynein-mediated spindle movements within the mother cell, thus ensuring such movements are polarized toward the daughter cell. Our data indicate that this activity relies on She1 binding to the microtubule-bound conformation of the dynein microtubule-binding domain, and to astral microtubules within mother cells. Our findings reveal how an asymmetrically localized MAP directionally tunes dynein activity by attenuating motor activity in a spatially confined manner.
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Affiliation(s)
- Kari H Ecklund
- Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, Colorado 80523, USA
| | - Megan E Bailey
- Department of Physiology and Biophysics, University of Washington, Seattle, Washington 98195, USA
| | - Kelly A Kossen
- Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, Colorado 80523, USA
| | - Carsten K Dietvorst
- Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, Colorado 80523, USA
| | - Charles L Asbury
- Department of Physiology and Biophysics, University of Washington, Seattle, Washington 98195, USA
| | - Steven M Markus
- Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, Colorado 80523, USA
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3
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Jain K, Khetan N, Yadav SA, Palani S, Athale CA. Collective dynein transport of the nucleus by pulling on astral microtubules during Saccharomyces cerevisiae mitosis. Yeast 2021; 38:352-366. [PMID: 33547820 DOI: 10.1002/yea.3552] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2020] [Revised: 01/19/2021] [Accepted: 01/25/2021] [Indexed: 11/06/2022] Open
Abstract
Positioning the nucleus at the bud neck during Saccharomyces cerevisiae mitosis involves pulling forces of cytoplasmic dynein localized in the daughter cell. Although genetic analysis has revealed a complex network positioning the nucleus, quantification of the forces acting on the nucleus and the number of dyneins driving the process has remained difficult. To better understand the collective forces involved in nuclear positioning, we compare a model of dyneins-driven microtubule (MT) pulling, MT pushing, and cytoplasmic drag to experiments. During S. cerevisiae mitosis, MTs interacting with the cortex nucleated by the daughter spindle pole body (SPB) (SPB-D) are longer than the mother SPB (SPB-M), increasing further during spindle elongation in anaphase. Interphasic SPB mobility is effectively diffusive, while the mitotic mobility is directed. By optimizing a computational model of the mobility of the nucleus due to diffusion and MTs pushing at the cell membrane to experiment, we estimate the viscosity governing the drag force on nuclei during positioning. A force balance model of mitotic SPB mobility compared to experimental mobility suggests that even one or two dynein dimers are sufficient to move the nucleus in the bud neck. Using stochastic computer simulations of a budding cell, we find that punctate dynein localization can generate sufficient force to reel in the nucleus to the bud neck. Compared to uniform motor localization, puncta involve fewer motors suggesting a functional role for motor clustering. Stochastic simulations also suggest that a higher number of force generators than predicted by force balance may be required to ensure the robustness of spindle positioning.
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Affiliation(s)
- Kunalika Jain
- Division of Biology, IISER Pune, Dr. Homi Bhabha Road, Pune, Maharashtra, 411008, India
| | - Neha Khetan
- Division of Biology, IISER Pune, Dr. Homi Bhabha Road, Pune, Maharashtra, 411008, India
| | - Shivani A Yadav
- Division of Biology, IISER Pune, Dr. Homi Bhabha Road, Pune, Maharashtra, 411008, India
| | - Saravanan Palani
- Centre for Mechanochemical Cell Biology and Division of Biomedical Sciences, Warwick Medical School, University of Warwick, Coventry, UK.,Department of Biochemistry, Indian Institute of Science (IISc), C.V. Raman Road, Bangalore, Karnataka, 560012, India
| | - Chaitanya A Athale
- Division of Biology, IISER Pune, Dr. Homi Bhabha Road, Pune, Maharashtra, 411008, India
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4
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Markus SM, Marzo MG, McKenney RJ. New insights into the mechanism of dynein motor regulation by lissencephaly-1. eLife 2020; 9:59737. [PMID: 32692650 PMCID: PMC7373426 DOI: 10.7554/elife.59737] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2020] [Accepted: 07/13/2020] [Indexed: 12/20/2022] Open
Abstract
Lissencephaly (‘smooth brain’) is a severe brain disease associated with numerous symptoms, including cognitive impairment, and shortened lifespan. The main causative gene of this disease – lissencephaly-1 (LIS1) – has been a focus of intense scrutiny since its first identification almost 30 years ago. LIS1 is a critical regulator of the microtubule motor cytoplasmic dynein, which transports numerous cargoes throughout the cell, and is a key effector of nuclear and neuronal transport during brain development. Here, we review the role of LIS1 in cellular dynein function and discuss recent key findings that have revealed a new mechanism by which this molecule influences dynein-mediated transport. In addition to reconciling prior observations with this new model for LIS1 function, we also discuss phylogenetic data that suggest that LIS1 may have coevolved with an autoinhibitory mode of cytoplasmic dynein regulation.
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Affiliation(s)
- Steven M Markus
- Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, United States
| | - Matthew G Marzo
- Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, United States
| | - Richard J McKenney
- Department of Molecular and Cellular Biology, University of California, Davis, Davis, United States
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5
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Estrem C, Moore JK. Astral microtubule forces alter nuclear organization and inhibit DNA repair in budding yeast. Mol Biol Cell 2019; 30:2000-2013. [PMID: 31067146 PMCID: PMC6727761 DOI: 10.1091/mbc.e18-12-0808] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022] Open
Abstract
Dividing cells must balance the maintenance of genome integrity with the generation of cytoskeletal forces that control chromosome position. In this study, we investigate how forces on astral microtubules impact the genome during cell division by using live-cell imaging of the cytoskeleton, chromatin, and DNA damage repair in budding yeast. Our results demonstrate that dynein-dependent forces on astral microtubules are propagated through the spindle during nuclear migration and when in excess can increase the frequency of double-stranded breaks (DSBs). Under these conditions, we find that homology-directed repair of DSBs is delayed, indicating antagonism between nuclear migration and the mechanism of homology-directed repair. These effects are partially rescued by mutants that weaken pericentric cohesion or mutants that decrease constriction on the nucleus as it moves through the bud neck. We propose that minimizing nuclear movement aids in finding a donor strand for homologous recombination.
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Affiliation(s)
- Cassi Estrem
- Department of Cell and Developmental Biology, University of Colorado School of Medicine, Aurora, CO 80045
| | - Jeffrey K Moore
- Department of Cell and Developmental Biology, University of Colorado School of Medicine, Aurora, CO 80045
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6
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Denarier E, Brousse C, Sissoko A, Andrieux A, Boscheron C. A neurodevelopmental TUBB2B β-tubulin mutation impairs Bim1 (yeast EB1)-dependent spindle positioning. Biol Open 2019; 8:bio.038620. [PMID: 30674462 PMCID: PMC6361202 DOI: 10.1242/bio.038620] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Malformations of the human cerebral cortex can be caused by mutations in tubulins that associate to compose microtubules. Cerebral cortical folding relies on neuronal migration and on progenitor proliferation partly dictated by microtubule-dependent mitotic spindle positioning. A single amino acid change, F265L, in the conserved TUBB2B β-tubulin gene has been identified in patients with abnormal cortex formation. A caveat for studying this mutation in mammalian cells is that nine genes encode β-tubulin in human. Here, we generate a yeast strain expressing F265L tubulin mutant as the sole source of β-tubulin. The F265L mutation does not preclude expression of a stable β-tubulin protein which is incorporated into microtubules. However, impaired cell growth was observed at high temperatures along with altered microtubule dynamics and stability. In addition, F265L mutation produces a highly specific mitotic spindle positioning defect related to Bim1 (yeast EB1) dysfunction. Indeed, F265L cells display an abnormal Bim1 recruitment profile at microtubule plus-ends. These results indicate that the F265L β-tubulin mutation affects microtubule plus-end complexes known to be important for microtubule dynamics and for microtubule function during mitotic spindle positioning.
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Affiliation(s)
- Eric Denarier
- Univ. Grenoble Alpes, Grenoble Institut des Neurosciences, GIN, F-38000, Grenoble, France.,Institut National de la Santé et de la Recherche Médicale (INSERM), U1216, F-38000, Grenoble, France.,Commissariat à l'Energie Atomique et aux Energies Alternatives (CEA), Biosciences and Biotechnology Institute of Grenoble, Grenoble, France
| | - Carine Brousse
- Institut National de la Transfusion Sanguine (INTS), F-75015 Paris, France
| | | | - Annie Andrieux
- Univ. Grenoble Alpes, Grenoble Institut des Neurosciences, GIN, F-38000, Grenoble, France.,Institut National de la Santé et de la Recherche Médicale (INSERM), U1216, F-38000, Grenoble, France.,Commissariat à l'Energie Atomique et aux Energies Alternatives (CEA), Biosciences and Biotechnology Institute of Grenoble, Grenoble, France
| | - Cécile Boscheron
- Univ. Grenoble Alpes, Grenoble Institut des Neurosciences, GIN, F-38000, Grenoble, France .,Institut National de la Santé et de la Recherche Médicale (INSERM), U1216, F-38000, Grenoble, France.,Institut de Biologie Structurale (IBS) , F-38000 Grenoble, France
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7
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She1 affects dynein through direct interactions with the microtubule and the dynein microtubule-binding domain. Nat Commun 2017; 8:2151. [PMID: 29247176 PMCID: PMC5732302 DOI: 10.1038/s41467-017-02004-2] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2017] [Accepted: 10/31/2017] [Indexed: 01/31/2023] Open
Abstract
Cytoplasmic dynein is an enormous minus end-directed microtubule motor. Rather than existing as bare tracks, microtubules are bound by numerous microtubule-associated proteins (MAPs) that have the capacity to affect various cellular functions, including motor-mediated transport. One such MAP is She1, a dynein effector that polarizes dynein-mediated spindle movements in budding yeast. Here, we characterize the molecular basis by which She1 affects dynein, providing the first such insight into which a MAP can modulate motor motility. We find that She1 affects the ATPase rate, microtubule-binding affinity, and stepping behavior of dynein, and that microtubule binding by She1 is required for its effects on dynein motility. Moreover, we find that She1 directly contacts the microtubule-binding domain of dynein, and that their interaction is sensitive to the nucleotide-bound state of the motor. Our data support a model in which simultaneous interactions between the microtubule and dynein enables She1 to directly affect dynein motility. Dynein is a microtubule motor the motility of which is affected by the microtubule-associated protein She1. Here, the authors show that She1 alters dynein stepping behavior and increases its microtubule affinity through simultaneous interactions with the microtubule and dynein microtubule binding domain.
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8
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Xiang X. Nuclear movement in fungi. Semin Cell Dev Biol 2017; 82:3-16. [PMID: 29241689 DOI: 10.1016/j.semcdb.2017.10.024] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2017] [Revised: 10/17/2017] [Accepted: 10/23/2017] [Indexed: 12/22/2022]
Abstract
Nuclear movement within a cell occurs in a variety of eukaryotic organisms including yeasts and filamentous fungi. Fungal molecular genetic studies identified the minus-end-directed microtubule motor cytoplasmic dynein as a critical protein for nuclear movement or orientation of the mitotic spindle contained in the nucleus. Studies in the budding yeast first indicated that dynein anchored at the cortex via its anchoring protein Num1 exerts pulling force on an astral microtubule to orient the anaphase spindle across the mother-daughter axis before nuclear division. Prior to anaphase, myosin V interacts with the plus end of an astral microtubule via Kar9-Bim1/EB1 and pulls the plus end along the actin cables to move the nucleus/spindle close to the bud neck. In addition, pushing or pulling forces generated from cortex-linked polymerization or depolymerization of microtubules drive nuclear movements in yeasts and possibly also in filamentous fungi. In filamentous fungi, multiple nuclei within a hyphal segment undergo dynein-dependent back-and-forth movements and their positioning is also influenced by cytoplasmic streaming toward the hyphal tip. In addition, nuclear movement occurs at various stages of fungal development and fungal infection of plant tissues. This review discusses our current understanding on the mechanisms of nuclear movement in fungal organisms, the importance of nuclear positioning and the regulatory strategies that ensure the proper positioning of nucleus/spindle.
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Affiliation(s)
- Xin Xiang
- Department of Biochemistry and Molecular Biology, Uniformed Services University of the Health Sciences - F. Edward Hébert School of Medicine, Bethesda, MD, USA.
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9
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Maekawa H, Neuner A, Rüthnick D, Schiebel E, Pereira G, Kaneko Y. Polo-like kinase Cdc5 regulates Spc72 recruitment to spindle pole body in the methylotrophic yeast Ogataea polymorpha. eLife 2017; 6:24340. [PMID: 28853395 PMCID: PMC5626484 DOI: 10.7554/elife.24340] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2016] [Accepted: 08/17/2017] [Indexed: 11/17/2022] Open
Abstract
Cytoplasmic microtubules (cMT) control mitotic spindle positioning in many organisms, and are therefore pivotal for successful cell division. Despite its importance, the temporal control of cMT formation remains poorly understood. Here we show that unlike the best-studied yeast Saccharomyces cerevisiae, position of pre-anaphase nucleus is not strongly biased toward bud neck in Ogataea polymorpha and the regulation of spindle positioning becomes active only shortly before anaphase. This is likely due to the unstable property of cMTs compared to those in S. cerevisiae. Furthermore, we show that cMT nucleation/anchoring is restricted at the level of recruitment of the γ-tubulin complex receptor, Spc72, to spindle pole body (SPB), which is regulated by the polo-like kinase Cdc5. Additionally, electron microscopy revealed that the cytoplasmic side of SPB is structurally different between G1 and anaphase. Thus, polo-like kinase dependent recruitment of γ-tubulin receptor to SPBs determines the timing of spindle orientation in O. polymorpha. Before a cell divides, it needs to duplicate its genetic material to provide the new daughter cell with a full set of genetic information. To do so, the cell forms a complex of proteins called the spindle apparatus, which is made up of string-like microtubules that divide the chromosomes evenly. In many organisms, the position of the spindle determines where in the cell this separation happens. However, in baker’s yeast, the location where the cell will divide is determined well before the spindle is formed. Unlike many other eukaryotic cells, these yeast cells divide asymmetrically and create buds that will form the new daughter cells. The position of this bud determines where the spindle should be located and where the chromosomes separate. The spindle itself is then organised by a structure called the spindle pole body, which connects to microtubules inside the cell nucleus and microtubules in the cell plasma. Several proteins control where and how the spindle forms, including a protein called the spindle pole component 72, or Spc72 for short, and an enzyme called Cdc5. However, until now it was unclear how spindle formation is timed and controlled in other yeast species. Now, Maekawa et al. have used fluorescent markers and time lapse microscopy to examine how the spindle forms in the yeast species Ogataea polymorpha, an important industrial yeast used to produce medicines and alcohol. The results show that in O. polymorpha, the positioning and orientation of the spindle only occurred very late in the cell cycle and the microtubules in the cell plasma remained unstable until the chromosomes were about to separate. This was linked to changes in the level of Spc72, which increased at the spindle pole body before the chromosomes separated and then dropped again. This was controlled by Cdc5. Understanding when and where microtubules are formed is an important step in understanding how cells divide. This is the first example of a budding yeast that creates new microtubules in the cell plasma every time the cell divides. Unravelling the molecular differences between yeast species could lead to new ways to optimise the use of industrial yeasts like O. polymorpha, or to combat disease-causing ones.
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Affiliation(s)
- Hiromi Maekawa
- Graduate School of Engineering, Osaka University, Suita, Japan.,Faculty of Agriculture, Kyushu University, Fukuoka, Japan
| | - Annett Neuner
- Zentrum für Molekulare Biologie der Universität Heidelberg, DKFZ-ZMBH Alliance, Heidelberg, Germany
| | - Diana Rüthnick
- Zentrum für Molekulare Biologie der Universität Heidelberg, DKFZ-ZMBH Alliance, Heidelberg, Germany
| | - Elmar Schiebel
- Zentrum für Molekulare Biologie der Universität Heidelberg, DKFZ-ZMBH Alliance, Heidelberg, Germany
| | - Gislene Pereira
- Centre for Organismal Studies, University of Heidelberg, Heidelberg, Germany.,Division of Centrosomes and Cilia, German Cancer Research Centre (DKFZ), DKFZ-ZMBH Alliance, Heidelberg, Germany
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10
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Zhu Y, An X, Tomaszewski A, Hepler PK, Lee WL. Microtubule cross-linking activity of She1 ensures spindle stability for spindle positioning. J Cell Biol 2017; 216:2759-2775. [PMID: 28794129 PMCID: PMC5584168 DOI: 10.1083/jcb.201701094] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2017] [Revised: 04/24/2017] [Accepted: 06/02/2017] [Indexed: 12/19/2022] Open
Abstract
Dynein orients the spindle by pulling on astral microtubules from the cortex. In Saccharomyces cerevisiae, the microtubule-associated protein She1 specifically inhibits dynein in the mother compartment to promote spindle movements toward the bud. Zhu et al. demonstrate that She1 also stabilizes interpolar microtubules, ensuring spindle integrity during dynein-mediated spindle positioning. Dynein mediates spindle positioning in budding yeast by pulling on astral microtubules (MTs) from the cell cortex. The MT-associated protein She1 regulates dynein activity along astral MTs and directs spindle movements toward the bud cell. In addition to localizing to astral MTs, She1 also targets to the spindle, but its role on the spindle remains unknown. Using function-separating alleles, live-cell spindle assays, and in vitro biochemical analyses, we show that She1 is required for the maintenance of metaphase spindle stability. She1 binds and cross-links MTs via a C-terminal MT-binding site. She1 can also self-assemble into ring-shaped oligomers. In cells, She1 stabilizes interpolar MTs, preventing spindle deformations during movement, and we show that this activity is regulated by Ipl1/Aurora B phosphorylation during cell cycle progression. Our data reveal how She1 ensures spindle integrity during spindle movement across the bud neck and suggest a potential link between regulation of spindle integrity and dynein pathway activity.
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Affiliation(s)
- Yili Zhu
- Molecular and Cellular Biology Graduate Program, University of Massachusetts, Amherst, MA.,Biology Department, University of Massachusetts, Amherst, MA
| | - Xiaojing An
- Biology Department, University of Massachusetts, Amherst, MA
| | | | - Peter K Hepler
- Biology Department, University of Massachusetts, Amherst, MA
| | - Wei-Lih Lee
- Biology Department, University of Massachusetts, Amherst, MA
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11
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Villoria MT, Ramos F, Dueñas E, Faull P, Cutillas PR, Clemente-Blanco A. Stabilization of the metaphase spindle by Cdc14 is required for recombinational DNA repair. EMBO J 2016; 36:79-101. [PMID: 27852625 PMCID: PMC5210157 DOI: 10.15252/embj.201593540] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2015] [Revised: 10/05/2016] [Accepted: 10/18/2016] [Indexed: 11/24/2022] Open
Abstract
Cells are constantly threatened by multiple sources of genotoxic stress that cause DNA damage. To maintain genome integrity, cells have developed a coordinated signalling network called DNA damage response (DDR). While multiple kinases have been thoroughly studied during DDR activation, the role of protein dephosphorylation in the damage response remains elusive. Here, we show that the phosphatase Cdc14 is essential to fulfil recombinational DNA repair in budding yeast. After DNA double‐strand break (DSB) generation, Cdc14 is transiently released from the nucleolus and activated. In this state, Cdc14 targets the spindle pole body (SPB) component Spc110 to counterbalance its phosphorylation by cyclin‐dependent kinase (Cdk). Alterations in the Cdk/Cdc14‐dependent phosphorylation status of Spc110, or its inactivation during the induction of a DNA lesion, generate abnormal oscillatory SPB movements that disrupt DSB‐SPB interactions. Remarkably, these defects impair DNA repair by homologous recombination indicating that SPB integrity is essential during the repair process. Together, these results show that Cdc14 promotes spindle stability and DSB‐SPB tethering during DNA repair, and imply that metaphase spindle maintenance is a critical feature of the repair process.
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Affiliation(s)
- María Teresa Villoria
- Cell Cycle and Genome Stability Group, Instituto de Biología Funcional y Genómica Consejo Superior de Investigaciones Científicas (CSIC) Universidad de Salamanca (USAL), Salamanca, Spain
| | - Facundo Ramos
- Cell Cycle and Genome Stability Group, Instituto de Biología Funcional y Genómica Consejo Superior de Investigaciones Científicas (CSIC) Universidad de Salamanca (USAL), Salamanca, Spain
| | - Encarnación Dueñas
- Cell Cycle and Genome Stability Group, Instituto de Biología Funcional y Genómica Consejo Superior de Investigaciones Científicas (CSIC) Universidad de Salamanca (USAL), Salamanca, Spain
| | - Peter Faull
- Biological Mass Spectrometry and Proteomics Laboratory, Medical Research Council Clinical Science Centre Imperial College, London, UK
| | - Pedro Rodríguez Cutillas
- Biological Mass Spectrometry and Proteomics Laboratory, Medical Research Council Clinical Science Centre Imperial College, London, UK
| | - Andrés Clemente-Blanco
- Cell Cycle and Genome Stability Group, Instituto de Biología Funcional y Genómica Consejo Superior de Investigaciones Científicas (CSIC) Universidad de Salamanca (USAL), Salamanca, Spain
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12
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Dasso M. Kar9 Controls the Cytoplasm by Visiting the Nucleus. Dev Cell 2016; 36:360-1. [PMID: 26906732 DOI: 10.1016/j.devcel.2016.02.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Kar9 positions mitotic spindles during budding yeast cell division. Reporting in this issue of Developmental Cell, Schweiggert et al. (2016) show that modulation of Kar9 stability mediates crosstalk between cytoplasmic and nuclear microtubules, using an elaborate mechanism that involves regulated nuclear transport as well as SUMOylation and ubiquitination.
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Affiliation(s)
- Mary Dasso
- Division of Molecular and Cellular Biology, National Institute for Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA.
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13
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di Pietro F, Echard A, Morin X. Regulation of mitotic spindle orientation: an integrated view. EMBO Rep 2016; 17:1106-30. [PMID: 27432284 DOI: 10.15252/embr.201642292] [Citation(s) in RCA: 201] [Impact Index Per Article: 25.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2016] [Accepted: 06/17/2016] [Indexed: 12/18/2022] Open
Abstract
Mitotic spindle orientation is essential for cell fate decisions, epithelial maintenance, and tissue morphogenesis. In most animal cell types, the dynein motor complex is anchored at the cell cortex and exerts pulling forces on astral microtubules to position the spindle. Early studies identified the evolutionarily conserved Gαi/LGN/NuMA complex as a key regulator that polarizes cortical force generators. In recent years, a combination of genetics, biochemistry, modeling, and live imaging has contributed to decipher the mechanisms of spindle orientation. Here, we highlight the dynamic nature of the assembly of this complex and discuss the molecular regulation of its localization. Remarkably, a number of LGN-independent mechanisms were described recently, whereas NuMA remains central in most pathways involved in recruiting force generators at the cell cortex. We also describe the emerging role of the actin cortex in spindle orientation and discuss how dynamic astral microtubule formation is involved. We further give an overview on instructive external signals that control spindle orientation in tissues. Finally, we discuss the influence of cell geometry and mechanical forces on spindle orientation.
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Affiliation(s)
- Florencia di Pietro
- Cell Division and Neurogenesis Laboratory, Ecole Normale Supérieure CNRS Inserm Institut de Biologie de l'Ecole Normale Supérieure (IBENS) PSL Research University, Paris, France Institute of Doctoral Studies (IFD), Sorbonne Universités Université Pierre et Marie Curie-Université Paris 6, Paris, France
| | - Arnaud Echard
- Membrane Traffic and Cell Division Laboratory, Cell Biology and Infection Department, Institut Pasteur, Paris, France Centre National de la Recherche Scientifique, Unité Mixte de Recherche 3691, Paris, France
| | - Xavier Morin
- Cell Division and Neurogenesis Laboratory, Ecole Normale Supérieure CNRS Inserm Institut de Biologie de l'Ecole Normale Supérieure (IBENS) PSL Research University, Paris, France
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14
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Sutradhar S, Yadav V, Sridhar S, Sreekumar L, Bhattacharyya D, Ghosh SK, Paul R, Sanyal K. A comprehensive model to predict mitotic division in budding yeasts. Mol Biol Cell 2015; 26:3954-65. [PMID: 26310442 PMCID: PMC4710229 DOI: 10.1091/mbc.e15-04-0236] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2015] [Accepted: 08/14/2015] [Indexed: 12/26/2022] Open
Abstract
A mechanistic in silico model predicts mitotic events and effects of perturbation in budding yeasts belonging to Ascomycota and Basidiomycota. The model identifies distinct pathways based on the population of cytoplasmic microtubules and cortical dyneins as determinants of nuclear and spindle positioning in these phyla. High-fidelity chromosome segregation during cell division depends on a series of concerted interdependent interactions. Using a systems biology approach, we built a robust minimal computational model to comprehend mitotic events in dividing budding yeasts of two major phyla: Ascomycota and Basidiomycota. This model accurately reproduces experimental observations related to spindle alignment, nuclear migration, and microtubule (MT) dynamics during cell division in these yeasts. The model converges to the conclusion that biased nucleation of cytoplasmic microtubules (cMTs) is essential for directional nuclear migration. Two distinct pathways, based on the population of cMTs and cortical dyneins, differentiate nuclear migration and spindle orientation in these two phyla. In addition, the model accurately predicts the contribution of specific classes of MTs in chromosome segregation. Thus we present a model that offers a wider applicability to simulate the effects of perturbation of an event on the concerted process of the mitotic cell division.
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Affiliation(s)
- Sabyasachi Sutradhar
- Department of Solid State Physics, Indian Association for the Cultivation of Science, Kolkata 700032, India
| | - Vikas Yadav
- Molecular Mycology Laboratory, Molecular Biology and Genetics Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore 560064, India
| | - Shreyas Sridhar
- Molecular Mycology Laboratory, Molecular Biology and Genetics Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore 560064, India
| | - Lakshmi Sreekumar
- Molecular Mycology Laboratory, Molecular Biology and Genetics Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore 560064, India
| | - Dibyendu Bhattacharyya
- Tata Memorial Centre, Advanced Centre for Treatment Research and Education in Cancer, Kharghar, Navi Mumbai 410210, India
| | - Santanu Kumar Ghosh
- Department of Biosciences and Bioengineering, Indian Institute of Technology, Bombay, Powai, Mumbai 400076, India
| | - Raja Paul
- Department of Solid State Physics, Indian Association for the Cultivation of Science, Kolkata 700032, India
| | - Kaustuv Sanyal
- Molecular Mycology Laboratory, Molecular Biology and Genetics Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore 560064, India
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15
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Baumgärtner S, Tolić IM. Astral microtubule pivoting promotes their search for cortical anchor sites during mitosis in budding yeast. PLoS One 2014; 9:e93781. [PMID: 24721997 PMCID: PMC3983083 DOI: 10.1371/journal.pone.0093781] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2013] [Accepted: 03/10/2014] [Indexed: 11/18/2022] Open
Abstract
Positioning of the mitotic spindle is crucial for proper cell division. In the budding yeast Saccharomyces cerevisiae, two mechanisms contribute to spindle positioning. In the Kar9 pathway, astral microtubules emanating from the daughter-bound spindle pole body interact via the linker protein Kar9 with the myosin Myo2, which moves the microtubule along the actin cables towards the neck. In the dynein pathway, astral microtubules off-load dynein onto the cortical anchor protein Num1, which is followed by dynein pulling on the spindle. Yet, the mechanism by which microtubules target cortical anchor sites is unknown. Here we quantify the pivoting motion of astral microtubules around the spindle pole bodies, which occurs during spindle translocation towards the neck and through the neck. We show that this pivoting is largely driven by the Kar9 pathway. The microtubules emanating from the daughter-bound spindle pole body pivot faster than those at the mother-bound spindle pole body. The Kar9 pathway reduces the time needed for an astral microtubule inside the daughter cell to start pulling on the spindle. Thus, we propose a new role for microtubule pivoting: By pivoting around the spindle pole body, microtubules explore the space laterally, which helps them search for cortical anchor sites in the context of spindle positioning in budding yeast.
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Affiliation(s)
- Stephan Baumgärtner
- Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, Germany
| | - Iva M. Tolić
- Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, Germany
- Division of Molecular Biology, Ruđer Bošković Institute, Zagreb, Croatia
- * E-mail:
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16
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Laporte D, Courtout F, Salin B, Ceschin J, Sagot I. An array of nuclear microtubules reorganizes the budding yeast nucleus during quiescence. ACTA ACUST UNITED AC 2013; 203:585-94. [PMID: 24247429 PMCID: PMC3840927 DOI: 10.1083/jcb.201306075] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The microtubule cytoskeleton is a highly dynamic network. In dividing cells, its complex architecture not only influences cell shape and movement but is also crucial for chromosome segregation. Curiously, nothing is known about the behavior of this cellular machinery in quiescent cells. Here we show that, upon quiescence entry, the Saccharomyces cerevisiae microtubule cytoskeleton is drastically remodeled. Indeed, while cytoplasmic microtubules vanish, the spindle pole body (SPB) assembles a long and stable monopolar array of nuclear microtubules that spans the entire nucleus. Consequently, the nucleolus is displaced. Kinetochores remain attached to microtubule tips but lose SPB clustering and distribute along the microtubule array, leading to a large reorganization of the nucleus. When cells exit quiescence, the nuclear microtubule array slowly depolymerizes and, by pulling attached centromeres back to the SPB, allows the recovery of a typical Rabl-like configuration. Finally, mutants that do not assemble a nuclear array of microtubules are impaired for both quiescence survival and exit.
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Affiliation(s)
- Damien Laporte
- Université de Bordeaux, Institut de Biochimie et Génétique Cellulaires, F-33077 Bordeaux Cedex, France
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17
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Akhshi TK, Wernike D, Piekny A. Microtubules and actin crosstalk in cell migration and division. Cytoskeleton (Hoboken) 2013; 71:1-23. [DOI: 10.1002/cm.21150] [Citation(s) in RCA: 110] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2013] [Revised: 10/02/2013] [Accepted: 10/06/2013] [Indexed: 12/22/2022]
Affiliation(s)
| | - Denise Wernike
- Department of Biology; Concordia University; Montreal Quebec Canada
| | - Alisa Piekny
- Department of Biology; Concordia University; Montreal Quebec Canada
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18
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Abstract
Asymmetric cell division (ACD), a mechanism for cell-type diversification in both prokaryotes and eukaryotes, is accomplished through highly coordinated cell-fate segregation, genome partitioning, and cell division. Whereas important paradigms have arisen from the study of animal embryonic divisions, the strategies for choreographing the dynamic subprocesses are, in fact, highly varied. This review examines divergent mechanisms of ACD across different kingdoms. Examples discussed show that there is no obligatory hierarchy among the dynamic events and that asymmetry can emerge from each event, but cell polarization more often occurs as the initial instructive process for patterning ACD especially in the multicellular context.
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Affiliation(s)
- Rong Li
- Stowers Institute for Medical Research, 1000 East 50th Street, Kansas City, MO 64110, USA.
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Best HA, Matthews JH, Heathcott RW, Hanna R, Leahy DC, Coorey NVC, Bellows DS, Atkinson PH, Miller JH. Laulimalide and peloruside A inhibit mitosis of Saccharomyces cerevisiae by preventing microtubule depolymerisation-dependent steps in chromosome separation and nuclear positioning. MOLECULAR BIOSYSTEMS 2013; 9:2842-52. [DOI: 10.1039/c3mb70211a] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
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