1
|
Aquino-Perez C, Safaralizade M, Podhajecky R, Wang H, Lansky Z, Grosse R, Macurek L. FAM110A promotes mitotic spindle formation by linking microtubules with actin cytoskeleton. Proc Natl Acad Sci U S A 2024; 121:e2321647121. [PMID: 38995965 PMCID: PMC11260166 DOI: 10.1073/pnas.2321647121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2024] [Accepted: 06/06/2024] [Indexed: 07/14/2024] Open
Abstract
Precise segregation of chromosomes during mitosis requires assembly of a bipolar mitotic spindle followed by correct attachment of microtubules to the kinetochores. This highly spatiotemporally organized process is controlled by various mitotic kinases and molecular motors. We have recently shown that Casein Kinase 1 (CK1) promotes timely progression through mitosis by phosphorylating FAM110A leading to its enrichment at spindle poles. However, the mechanism by which FAM110A exerts its function in mitosis is unknown. Using structure prediction and a set of deletion mutants, we mapped here the interaction of the N- and C-terminal domains of FAM110A with actin and tubulin, respectively. Next, we found that the FAM110A-Δ40-61 mutant deficient in actin binding failed to rescue defects in chromosomal alignment caused by depletion of endogenous FAM110A. Depletion of FAM110A impaired assembly of F-actin in the proximity of spindle poles and was rescued by expression of the wild-type FAM110A, but not the FAM110A-Δ40-61 mutant. Purified FAM110A promoted binding of F-actin to microtubules as well as bundling of actin filaments in vitro. Finally, we found that the inhibition of CK1 impaired spindle actin formation and delayed progression through mitosis. We propose that CK1 and FAM110A promote timely progression through mitosis by mediating the interaction between spindle microtubules and filamentous actin to ensure proper mitotic spindle formation.
Collapse
Affiliation(s)
- Cecilia Aquino-Perez
- Cancer Cell Biology, Institute of Molecular Genetics, Czech Academy of Sciences, PragueCZ14220, Czech Republic
| | - Mahira Safaralizade
- Institute for Clinical and Experimental Pharmacology and Toxicology I, Medical Faculty, University of Freiburg, Freiburg79104, Germany
| | - Roman Podhajecky
- Institute of Biotechnology, Czech Academy of Sciences, Biocev, VestecCZ25250, Czech Republic
| | - Hong Wang
- Institute for Clinical and Experimental Pharmacology and Toxicology I, Medical Faculty, University of Freiburg, Freiburg79104, Germany
- Centre for Integrative Biological Signaling Studies, University of Freiburg, Freiburg79104, Germany
| | - Zdenek Lansky
- Institute of Biotechnology, Czech Academy of Sciences, Biocev, VestecCZ25250, Czech Republic
| | - Robert Grosse
- Institute for Clinical and Experimental Pharmacology and Toxicology I, Medical Faculty, University of Freiburg, Freiburg79104, Germany
- Centre for Integrative Biological Signaling Studies, University of Freiburg, Freiburg79104, Germany
| | - Libor Macurek
- Cancer Cell Biology, Institute of Molecular Genetics, Czech Academy of Sciences, PragueCZ14220, Czech Republic
| |
Collapse
|
2
|
Garrido-Casado M, Asensio-Juárez G, Vicente-Manzanares M. Nonmuscle Myosin II Regulation Directs Its Multiple Roles in Cell Migration and Division. Annu Rev Cell Dev Biol 2021; 37:285-310. [PMID: 34314591 DOI: 10.1146/annurev-cellbio-042721-105528] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Nonmuscle myosin II (NMII) is a multimeric protein complex that generates most mechanical force in eukaryotic cells. NMII function is controlled at three main levels. The first level includes events that trigger conformational changes that extend the complex to enable its assembly into filaments. The second level controls the ATPase activity of the complex and its binding to microfilaments in extended NMII filaments. The third level includes events that modulate the stability and contractility of the filaments. They all work in concert to finely control force generation inside cells. NMII is a common endpoint of mechanochemical signaling pathways that control cellular responses to physical and chemical extracellular cues. Specific phosphorylations modulate NMII activation in a context-dependent manner. A few kinases control these phosphorylations in a spatially, temporally, and lineage-restricted fashion, enabling functional adaptability to the cellular microenvironment. Here, we review mechanisms that control NMII activity in the context of cell migration and division. Expected final online publication date for the Annual Review of Cell and Developmental Biology, Volume 37 is October 2021. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.
Collapse
Affiliation(s)
- Marina Garrido-Casado
- Molecular Mechanisms Program, Centro de Investigación del Cáncer and Instituto de Biología Molecular y Celular del Cáncer, Consejo Superior de Investigaciones Científicas, University of Salamanca, 37007 Salamanca, Spain;
| | - Gloria Asensio-Juárez
- Molecular Mechanisms Program, Centro de Investigación del Cáncer and Instituto de Biología Molecular y Celular del Cáncer, Consejo Superior de Investigaciones Científicas, University of Salamanca, 37007 Salamanca, Spain;
| | - Miguel Vicente-Manzanares
- Molecular Mechanisms Program, Centro de Investigación del Cáncer and Instituto de Biología Molecular y Celular del Cáncer, Consejo Superior de Investigaciones Científicas, University of Salamanca, 37007 Salamanca, Spain;
| |
Collapse
|
3
|
Sato M, Kakui Y, Toya M. Tell the Difference Between Mitosis and Meiosis: Interplay Between Chromosomes, Cytoskeleton, and Cell Cycle Regulation. Front Cell Dev Biol 2021; 9:660322. [PMID: 33898463 PMCID: PMC8060462 DOI: 10.3389/fcell.2021.660322] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2021] [Accepted: 03/02/2021] [Indexed: 12/04/2022] Open
Abstract
Meiosis is a specialized style of cell division conserved in eukaryotes, particularly designed for the production of gametes. A huge number of studies to date have demonstrated how chromosomes behave and how meiotic events are controlled. Yeast substantially contributed to the understanding of the molecular mechanisms of meiosis in the past decades. Recently, evidence began to accumulate to draw a perspective landscape showing that chromosomes and microtubules are mutually influenced: microtubules regulate chromosomes, whereas chromosomes also regulate microtubule behaviors. Here we focus on lessons from recent advancement in genetical and cytological studies of the fission yeast Schizosaccharomyces pombe, revealing how chromosomes, cytoskeleton, and cell cycle progression are organized and particularly how these are differentiated in mitosis and meiosis. These studies illuminate that meiosis is strategically designed to fulfill two missions: faithful segregation of genetic materials and production of genetic diversity in descendants through elaboration by meiosis-specific factors in collaboration with general factors.
Collapse
Affiliation(s)
- Masamitsu Sato
- Laboratory of Cytoskeletal Logistics, Center for Advanced Biomedical Sciences (TWIns), Waseda University, Tokyo, Japan.,Institute for Advanced Research of Biosystem Dynamics, Waseda Research Institute for Science and Engineering, Graduate School of Advanced Science and Engineering, Waseda University, Tokyo, Japan.,Institute for Medical-Oriented Structural Biology, Waseda University, Tokyo, Japan
| | - Yasutaka Kakui
- Laboratory of Cytoskeletal Logistics, Center for Advanced Biomedical Sciences (TWIns), Waseda University, Tokyo, Japan.,Waseda Institute for Advanced Study, Waseda University, Tokyo, Japan
| | - Mika Toya
- Laboratory of Cytoskeletal Logistics, Center for Advanced Biomedical Sciences (TWIns), Waseda University, Tokyo, Japan.,Institute for Advanced Research of Biosystem Dynamics, Waseda Research Institute for Science and Engineering, Graduate School of Advanced Science and Engineering, Waseda University, Tokyo, Japan.,Major in Bioscience, Global Center for Science and Engineering, Faculty of Science and Engineering, Waseda University, Tokyo, Japan
| |
Collapse
|
4
|
Renda F, Khodjakov A. Role of spatial patterns and kinetochore architecture in spindle morphogenesis. Semin Cell Dev Biol 2021; 117:75-85. [PMID: 33836948 PMCID: PMC8762378 DOI: 10.1016/j.semcdb.2021.03.016] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2021] [Revised: 03/25/2021] [Accepted: 03/25/2021] [Indexed: 12/30/2022]
Abstract
Mitotic spindle is a self-assembling macromolecular machine responsible for the faithful segregation of chromosomes during cell division. Assembly of the spindle is believed to be governed by the 'Search & Capture' (S&C) principle in which dynamic microtubules explore space in search of kinetochores while the latter capture microtubules and thus connect chromosomes to the spindle. Due to the stochastic nature of the encounters between kinetochores and microtubules, the time required for incorporating all chromosomes into the spindle is profoundly affected by geometric constraints, such as the size and shape of kinetochores as well as their distribution in space at the onset of spindle assembly. In recent years, several molecular mechanisms that control these parameters have been discovered. It is now clear that stochastic S&C takes place in structured space, where components are optimally distributed and oriented to minimize steric hindrances. Nucleation of numerous non-centrosomal microtubules near kinetochores accelerates capture, while changes in the kinetochore architecture at various stages of spindle assembly promote proper connection of sister kinetochores to the opposite spindle poles. Here we discuss how the concerted action of multiple facilitating mechanisms ensure that the spindle assembles rapidly yet with a minimal number of errors.
Collapse
Affiliation(s)
- Fioranna Renda
- Biggs Laboratory, Wadsworth Center, New York State Department of Health, Empire State Plaza, Albany, NY 12237, United States.
| | - Alexey Khodjakov
- Biggs Laboratory, Wadsworth Center, New York State Department of Health, Empire State Plaza, Albany, NY 12237, United States; Rensselaer Polytechnic Institute, Troy, NY 12180, United States.
| |
Collapse
|
5
|
Shagieva GS, Alieva IB, Chaponnier C, Dugina VB. Divergent Impact of Actin Isoforms on Division of Epithelial Cells. BIOCHEMISTRY (MOSCOW) 2021; 85:1072-1063. [PMID: 33050852 DOI: 10.1134/s0006297920090072] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
We investigated distribution and functions of beta- and gamma-cytoplasmic actins (CYAs) at different stages of non-neoplastic epithelial cell division using laser scanning microscopy (LSM). Here, we demonstrated that beta- and gamma-CYAs are spatially segregated in the early prophase, anaphase, telophase, and cytokinesis. Small interfering RNA (siRNA) experiments revealed that in both beta-CYA- and gamma-CYA-depleted cells, the number of cells was significantly reduced compared with the siRNA controls. Beta-CYA depletion resulted in an enlargement of the cell area in metaphase and high percentage of polynuclear cells compared with the siRNA control, indicating a potential failure of cytokinesis. Gamma-CYA depletion resulted in a reduced percentage of mitotic cells. We also observed the interdependence between the actin isoforms and the microtubule system in mitosis: (i) a decrease in the gamma-CYA led to impaired mitotic spindle organization; (ii) suppression of tubulin polymerization caused impaired beta-CYA reorganization, as incubation with colcemid blocked the transfer of short beta-actin polymers from the basal to the cortical compartment. We conclude that both actin isoforms are essential for proper cell division, but each isoform has its own specific functional role in this process.
Collapse
Affiliation(s)
- G S Shagieva
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, 119992, Russia
| | - I B Alieva
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, 119992, Russia. .,Federal Research and Clinical Center of Physical-Chemical Medicine of the Federal Medical Biological Agency, Moscow, 119435, Russia
| | - C Chaponnier
- Department of Pathology and Immunology, Faculty of Medicine, University of Geneva, Geneva, 1205, Switzerland
| | - V B Dugina
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, 119992, Russia
| |
Collapse
|
6
|
Mogessie B. Advances and surprises in a decade of oocyte meiosis research. Essays Biochem 2020; 64:263-275. [PMID: 32538429 DOI: 10.1042/ebc20190068] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2020] [Revised: 05/22/2020] [Accepted: 05/26/2020] [Indexed: 12/30/2022]
Abstract
Eggs are produced from progenitor oocytes through meiotic cell division. Fidelity of meiosis is critical for healthy embryogenesis - fertilisation of aneuploid eggs that contain the wrong number of chromosomes is a leading cause of genetic disorders including Down's syndrome, human embryo deaths and infertility. Incidence of meiosis-related oocyte and egg aneuploidies increases dramatically with advancing maternal age, which further complicates the 'meiosis problem'. We have just emerged from a decade of meiosis research that was packed with exciting and transformative research. This minireview will focus primarily on studies of mechanisms that directly influence chromosome segregation.
Collapse
Affiliation(s)
- Binyam Mogessie
- School of Biochemistry, University of Bristol, Bristol BS8 1TD, U.K
| |
Collapse
|
7
|
Menanteau–Ledouble S, Gotesman M, Razzazi‐Fazeli E, Bergmann SM, El‐Matbouli M. Elucidation of putative binding partners for the protein encoded by ORF149 of cyprinid herpesvirus 3 in goldfish (Carassius auratus). JOURNAL OF FISH DISEASES 2020; 43:707-710. [PMID: 32323354 PMCID: PMC7318325 DOI: 10.1111/jfd.13171] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/11/2020] [Revised: 03/17/2020] [Accepted: 03/20/2020] [Indexed: 05/02/2023]
Affiliation(s)
- Simon Menanteau–Ledouble
- Clinical Division of Fish MedicineDepartment for Farm Animals and Veterinary Public HealthUniversity of Veterinary MedicineViennaAustria
| | - Michael Gotesman
- Department of BiologyNew York City College of Technology of the City University of New YorkBrooklynNYUSA
- Protein DivisionIbex Biosciences LLCCumberlandMDUSA
| | | | - Sven M. Bergmann
- Federal Research Institute for Animal HealthFriedrich‐Loeffler InstitutGreifswald‐Insel RiemsGermany
| | - Mansour El‐Matbouli
- Clinical Division of Fish MedicineDepartment for Farm Animals and Veterinary Public HealthUniversity of Veterinary MedicineViennaAustria
| |
Collapse
|
8
|
Kullmann JA, Meyer S, Pipicelli F, Kyrousi C, Schneider F, Bartels N, Cappello S, Rust MB. Profilin1-Dependent F-Actin Assembly Controls Division of Apical Radial Glia and Neocortex Development. Cereb Cortex 2019; 30:3467-3482. [DOI: 10.1093/cercor/bhz321] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2019] [Revised: 10/24/2019] [Accepted: 11/11/2019] [Indexed: 12/28/2022] Open
Abstract
Abstract
Neocortex development depends on neural stem cell proliferation, cell differentiation, neurogenesis, and neuronal migration. Cytoskeletal regulation is critical for all these processes, but the underlying mechanisms are only poorly understood. We previously implicated the cytoskeletal regulator profilin1 in cerebellar granule neuron migration. Since we found profilin1 expressed throughout mouse neocortex development, we here tested the hypothesis that profilin1 is crucial for neocortex development. We found no evidence for impaired neuron migration or layering in the neocortex of profilin1 mutant mice. However, proliferative activity at basal positions was doubled in the mutant neocortex during mid-neurogenesis, with a drastic and specific increase in basal Pax6+ cells indicative for elevated numbers of basal radial glia (bRG). This was accompanied by transiently increased neurogenesis and associated with mild invaginations resembling rudimentary neocortex folds. Our data are in line with a model in which profilin1-dependent actin assembly controls division of apical radial glia (aRG) and thereby the fate of their progenies. Via this mechanism, profilin1 restricts cell delamination from the ventricular surface and, hence, bRG production and thereby controls neocortex development in mice. Our data support the radial cone hypothesis” claiming that elevated bRG number causes neocortex folds.
Collapse
Affiliation(s)
- Jan A Kullmann
- Molecular Neurobiology Group, Institute of Physiological Chemistry, Philipps-University of Marburg, 35032 Marburg, Germany
- Center for Mind, Brain and Behavior (CMBB), University of Marburg and Justus-Liebig-University Giessen, Hans-Meerwein-Strasse 6, 35032 Marburg, Germany
| | - Sophie Meyer
- Molecular Neurobiology Group, Institute of Physiological Chemistry, Philipps-University of Marburg, 35032 Marburg, Germany
- Center for Mind, Brain and Behavior (CMBB), University of Marburg and Justus-Liebig-University Giessen, Hans-Meerwein-Strasse 6, 35032 Marburg, Germany
| | - Fabrizia Pipicelli
- Max-Planck Institute for Psychiatry, Kraepelinstrasse 2-10, 80804 Munich, Germany
- International Max Planck Research School for Translational Psychiatry (IMPRS-TP), Kraepelinstrasse 2-10, 80804 Munich, Germany
| | - Christina Kyrousi
- Max-Planck Institute for Psychiatry, Kraepelinstrasse 2-10, 80804 Munich, Germany
| | - Felix Schneider
- Molecular Neurobiology Group, Institute of Physiological Chemistry, Philipps-University of Marburg, 35032 Marburg, Germany
- Center for Mind, Brain and Behavior (CMBB), University of Marburg and Justus-Liebig-University Giessen, Hans-Meerwein-Strasse 6, 35032 Marburg, Germany
- DFG Research Training Group, Membrane Plasticity in Tissue Development and Remodeling, GRK 2213, Philipps-University of Marburg, 35032 Marburg, Germany
| | - Nora Bartels
- Molecular Neurobiology Group, Institute of Physiological Chemistry, Philipps-University of Marburg, 35032 Marburg, Germany
| | - Silvia Cappello
- Max-Planck Institute for Psychiatry, Kraepelinstrasse 2-10, 80804 Munich, Germany
| | - Marco B Rust
- Molecular Neurobiology Group, Institute of Physiological Chemistry, Philipps-University of Marburg, 35032 Marburg, Germany
- Center for Mind, Brain and Behavior (CMBB), University of Marburg and Justus-Liebig-University Giessen, Hans-Meerwein-Strasse 6, 35032 Marburg, Germany
- DFG Research Training Group, Membrane Plasticity in Tissue Development and Remodeling, GRK 2213, Philipps-University of Marburg, 35032 Marburg, Germany
| |
Collapse
|
9
|
Heikenwalder M, Lorentzen A. The role of polarisation of circulating tumour cells in cancer metastasis. Cell Mol Life Sci 2019; 76:3765-3781. [PMID: 31218452 PMCID: PMC6744547 DOI: 10.1007/s00018-019-03169-3] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2019] [Revised: 04/23/2019] [Accepted: 05/29/2019] [Indexed: 02/06/2023]
Abstract
Metastasis is the spread of cancer cells from a primary tumour to a distant site of the body. Metastasising tumour cells have to survive and readjust to different environments, such as heterogeneous solid tissues and liquid phase in lymph- or blood circulation, which they achieve through a high degree of plasticity that renders them adaptable to varying conditions. One defining characteristic of the metastatic process is the transition of tumour cells between different polarised phenotypes, ranging from differentiated epithelial polarity to migratory front-rear polarity. Here, we review the polarisation types adopted by tumour cells during the metastatic process and describe the recently discovered single-cell polarity in liquid phase observed in circulating tumour cells. We propose that single-cell polarity constitutes a mode of polarisation of the cell cortex that is uncoupled from the intracellular polarisation machinery, which distinguishes single-cell polarity from other types of polarity identified so far. We discuss how single-cell polarity can contribute to tumour metastasis and the therapeutic potential of this new discovery.
Collapse
Affiliation(s)
- Mathias Heikenwalder
- Divison of Chronic Inflammation and Cancer, German Cancer Research Center (DKFZ), 69120, Heidelberg, Germany.
| | - Anna Lorentzen
- Department of Molecular Biology and Genetics, Aarhus University, 8000, Aarhus, Denmark.
| |
Collapse
|
10
|
Plessner M, Knerr J, Grosse R. Centrosomal Actin Assembly Is Required for Proper Mitotic Spindle Formation and Chromosome Congression. iScience 2019; 15:274-281. [PMID: 31096079 PMCID: PMC6520610 DOI: 10.1016/j.isci.2019.04.022] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2019] [Revised: 03/29/2019] [Accepted: 04/17/2019] [Indexed: 02/07/2023] Open
Abstract
Cytoskeletal cross talk between actin filaments and microtubules is a common mechanism governing the assembly of cellular structures, i.e., during filopodia formation or cilia organization. However, potential actin-microtubule interactions during mammalian cell divisions are less well understood. At mitotic entry, centrosomes propagate the formation of the mitotic spindle, thereby aligning individual chromosomes to the metaphase plate, a process coined chromosome congression. Here, we identify actin filament assembly spatially defined at centrosomes contemporaneously with spindle microtubules forming during prometaphase. We show that pharmacological Arp2/3 complex inhibition as well as overexpression of the Arp2/3 complex inhibitory protein Arpin decreased spindle actin. As a consequence, mitotic spindle formation is impaired, which resulted in disorganized chromosome congression and ultimately mitotic defects in non-transformed cells. Thus centrosomal Arp2/3 complex activity plays a role in the maintenance of genomic integrity during mitosis.
Collapse
Affiliation(s)
- Matthias Plessner
- Institute of Pharmacology, University of Freiburg, Albertstr. 25, 79104 Freiburg, Germany; CIBSS - Centre for Integrative Biological Signalling Studies, University of Freiburg, Schänzlestr. 18, 79104 Freiburg, Germany.
| | - Julian Knerr
- Institute of Pharmacology, University of Freiburg, Albertstr. 25, 79104 Freiburg, Germany
| | - Robert Grosse
- Institute of Pharmacology, University of Freiburg, Albertstr. 25, 79104 Freiburg, Germany; CIBSS - Centre for Integrative Biological Signalling Studies, University of Freiburg, Schänzlestr. 18, 79104 Freiburg, Germany.
| |
Collapse
|
11
|
Kita AM, Swider ZT, Erofeev I, Halloran MC, Goryachev AB, Bement WM. Spindle-F-actin interactions in mitotic spindles in an intact vertebrate epithelium. Mol Biol Cell 2019; 30:1645-1654. [PMID: 31091161 PMCID: PMC6727749 DOI: 10.1091/mbc.e19-02-0126] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022] Open
Abstract
Mitotic spindles are well known to be assembled from and dependent on microtubules. In contrast, whether actin filaments (F-actin) are required for or are even present in mitotic spindles has long been controversial. Here we have developed improved methods for simultaneously preserving F-actin and microtubules in fixed samples and exploited them to demonstrate that F-actin is indeed associated with mitotic spindles in intact Xenopus laevis embryonic epithelia. We also find that there is an “F-actin cycle,” in which the distribution and organization of spindle F-actin changes over the course of the cell cycle. Live imaging using a probe for F-actin reveals that at least two pools of F-actin are associated with mitotic spindles: a relatively stable internal network of cables that moves in concert with and appears to be linked to spindles, and F-actin “fingers” that rapidly extend from the cell cortex toward the spindle and make transient contact with the spindle poles. We conclude that there is a robust endoplasmic F-actin network in normal vertebrate epithelial cells and that this network is also a component of mitotic spindles. More broadly, we conclude that there is far more internal F-actin in epithelial cells than is commonly believed.
Collapse
Affiliation(s)
- Angela M Kita
- Cellular and Molecular Biology Graduate Program, University of Wisconsin-Madison, Madison, WI 53706.,Laboratory of Cell and Molecular Biology, University of Wisconsin-Madison, Madison, WI 53706
| | - Zachary T Swider
- Cellular and Molecular Biology Graduate Program, University of Wisconsin-Madison, Madison, WI 53706.,Laboratory of Cell and Molecular Biology, University of Wisconsin-Madison, Madison, WI 53706
| | - Ivan Erofeev
- Centre for Synthetic and Systems Biology, University of Edinburgh, Edinburgh EH9 3JD, United Kingdom
| | - Mary C Halloran
- Department of Integrative Biology, University of Wisconsin-Madison, Madison, WI 53706.,Department of Neuroscience, University of Wisconsin-Madison, Madison, WI 53706
| | - Andrew B Goryachev
- Centre for Synthetic and Systems Biology, University of Edinburgh, Edinburgh EH9 3JD, United Kingdom
| | - William M Bement
- Cellular and Molecular Biology Graduate Program, University of Wisconsin-Madison, Madison, WI 53706.,Laboratory of Cell and Molecular Biology, University of Wisconsin-Madison, Madison, WI 53706.,Department of Integrative Biology, University of Wisconsin-Madison, Madison, WI 53706
| |
Collapse
|
12
|
|
13
|
Abstract
Fertilizable eggs develop from diploid precursor cells termed oocytes. Once every menstrual cycle, an oocyte matures into a fertilizable egg in the ovary. To this end, the oocyte eliminates half of its chromosomes into a small cell termed a polar body. The egg is then released into the Fallopian tube, where it can be fertilized. Upon fertilization, the egg completes the second meiotic division, and the mitotic division of the embryo starts. This review highlights recent work that has shed light on the cytoskeletal structures that drive the meiotic divisions of the oocyte in mammals. In particular, we focus on how mammalian oocytes assemble a microtubule spindle in the absence of centrosomes, how they position the spindle in preparation for polar body extrusion, and how the spindle segregates the chromosomes. We primarily focus on mouse oocytes as a model system but also highlight recent insights from human oocytes.
Collapse
Affiliation(s)
- Binyam Mogessie
- Department of Meiosis, Max Planck Institute for Biophysical Chemistry, 37077 Göttingen, Germany;
- Current affiliation: School of Biochemistry, University of Bristol, Bristol, BS8 1TD, United Kingdom
| | - Kathleen Scheffler
- Department of Meiosis, Max Planck Institute for Biophysical Chemistry, 37077 Göttingen, Germany;
| | - Melina Schuh
- Department of Meiosis, Max Planck Institute for Biophysical Chemistry, 37077 Göttingen, Germany;
| |
Collapse
|
14
|
Nuclear actin: ancient clue to evolution in eukaryotes? Histochem Cell Biol 2018; 150:235-244. [DOI: 10.1007/s00418-018-1693-6] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/29/2018] [Indexed: 12/31/2022]
|
15
|
Franchini V, De Sanctis S, Marinaccio J, De Amicis A, Coluzzi E, Di Cristofaro S, Lista F, Regalbuto E, Doria A, Giovenale E, Gallerano GP, Bei R, Benvenuto M, Masuelli L, Udroiu I, Sgura A. Study of the effects of 0.15 terahertz radiation on genome integrity of adult fibroblasts. ENVIRONMENTAL AND MOLECULAR MUTAGENESIS 2018; 59:476-487. [PMID: 29602275 DOI: 10.1002/em.22192] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/30/2017] [Revised: 03/06/2018] [Accepted: 03/08/2018] [Indexed: 05/18/2023]
Abstract
The applications of Terahertz (THz) technologies have significantly developed in recent years, and the complete understanding of the biological effects of exposure to THz radiation is becoming increasingly important. In a previous study, we found that THz radiation induced genomic damage in fetal fibroblasts. Although these cells demonstrated to be a useful model, exposure of human foetuses to THz radiation is highly improbable. Conversely, THz irradiation of adult dermal tissues is cause of possible concern for some professional and nonprofessional categories. Therefore, we extended our study to the investigation of the effects of THz radiation on adult fibroblasts (HDF). In this work, the effects of THz exposure on HDF cells genome integrity, cell cycle, cytological ultrastructure and proteins expression were assessed. Results of centromere-negative micronuclei frequencies, phosphorylation of H2AX histone, and telomere length modulation indicated no induction of DNA damage. Concordantly, no changes in the expression of proteins associated with DNA damage sensing and repair were detected. Conversely, our results showed an increase of centromere-positive micronuclei frequencies and chromosomal nondisjunction events, indicating induction of aneuploidy. Therefore, our results indicate that THz radiation exposure may affect genome integrity through aneugenic effects, and not by DNA breakage. Our findings are compared to published studies, and possible biophysical mechanisms are discussed. Environ. Mol. Mutagen. 59:476-487, 2018. © 2018 Wiley Periodicals, Inc.
Collapse
Affiliation(s)
- Valeria Franchini
- Scientific Department, Army Medical Center, Rome, Italy
- Department of Science, University "Roma Tre", Rome, Italy
| | | | | | | | - Elisa Coluzzi
- Department of Science, University "Roma Tre", Rome, Italy
| | | | | | - Elisa Regalbuto
- Scientific Department, Army Medical Center, Rome, Italy
- Department of Science, University "Roma Tre", Rome, Italy
| | - Andrea Doria
- Radiation Sources Laboratory, ENEA Frascati Research Center, Frascati, Italy
| | - Emilio Giovenale
- Radiation Sources Laboratory, ENEA Frascati Research Center, Frascati, Italy
| | | | - Roberto Bei
- Department of Clinical Sciences and Translational Medicine, University of Rome "Tor Vergata", Rome, Italy
| | - Monica Benvenuto
- Department of Clinical Sciences and Translational Medicine, University of Rome "Tor Vergata", Rome, Italy
| | - Laura Masuelli
- Department of Experimental Medicine, University of Rome "Sapienza", Rome, Italy
| | - Ion Udroiu
- Department of Science, University "Roma Tre", Rome, Italy
| | | |
Collapse
|
16
|
Sun H, Furt F, Vidali L. Myosin XI localizes at the mitotic spindle and along the cell plate during plant cell division in Physcomitrella patens. Biochem Biophys Res Commun 2018; 506:409-421. [PMID: 29339158 DOI: 10.1016/j.bbrc.2018.01.082] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2017] [Accepted: 01/11/2018] [Indexed: 01/08/2023]
Abstract
Cell division is a fundamental biological process that has been extensively investigated in different systems. Similar to most eukaryotic cells, plant cells assemble a mitotic spindle to separate replicated chromosomes. In contrast, to complete cell division, plant cells assemble a phragmoplast, which is composed of aligned microtubules and actin filaments. This structure helps transport vesicles containing new cell wall material, which then fuse to form the cell plate; the cell plate will expand to create the new dividing cell wall. Because vesicles are known to be transported by myosin motors during interphase, we hypothesized this could also be the case during cell division and we investigated the localization of the plant homologue of myosin V - myosin XI, in cell division. In this work, we used the protonemal cells of the moss Physcomitrella patens as a model, because of its simple cellular morphology and ease to generate transgenic cell lines expressing fluorescent tagged proteins. Using a fluorescent protein fusion of myosin XI, we found that, during mitosis, this molecule appears to associate with the kinetochores immediately after nuclear envelope breakdown. Following metaphase, myosin XI stays associated with the spindle's midzone during the rest of mitosis, and when the phragmoplast is formed, it concentrates at the cell plate. Using an actin polymerization inhibitor, latrunculin B, we found that the association of myosin XI with the mitotic spindle and the phragmoplast are only partially dependent on the presence of filamentous actin. We also showed that myosin XI on the spindle partially overlaps with a v-SNARE vesicle marker but is not co-localized with the endoplasmic reticulum and a RabA vesicle marker. These observations suggest an actin-dependent and an actin-independent behavior of myosin XI during cell division, and provide novel insights to our understanding of the function of myosin XI during plant cell division.
Collapse
Affiliation(s)
- Hao Sun
- Department of Biology and Biotechnology, Worcester Polytechnic Institute, Worcester, MA 01609, USA
| | - Fabienne Furt
- Department of Biology and Biotechnology, Worcester Polytechnic Institute, Worcester, MA 01609, USA
| | - Luis Vidali
- Department of Biology and Biotechnology, Worcester Polytechnic Institute, Worcester, MA 01609, USA.
| |
Collapse
|
17
|
Mogessie B, Schuh M. Actin protects mammalian eggs against chromosome segregation errors. Science 2017; 357:357/6353/eaal1647. [DOI: 10.1126/science.aal1647] [Citation(s) in RCA: 102] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2017] [Accepted: 06/28/2017] [Indexed: 11/02/2022]
|
18
|
Dewey EB, Johnston CA. Diverse mitotic functions of the cytoskeletal cross-linking protein Shortstop suggest a role in Dynein/Dynactin activity. Mol Biol Cell 2017; 28:2555-2568. [PMID: 28747439 PMCID: PMC5597327 DOI: 10.1091/mbc.e17-04-0219] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2017] [Revised: 06/19/2017] [Accepted: 07/19/2017] [Indexed: 12/20/2022] Open
Abstract
Shortstop (Shot), an actin–microtubule cross-linking protein, interacts with the Dynactin component Arp-1 to control mitotic spindle assembly and positioning in Drosophila. Shot is important for proper chromosome congression and segregation. Loss of Shot in epithelial tissue leads to significant apoptosis, which when blocked leads to epithelial–mesenchymal transition-like changes. Proper assembly and orientation of the bipolar mitotic spindle is critical to the fidelity of cell division. Mitotic precision fundamentally contributes to cell fate specification, tissue development and homeostasis, and chromosome distribution within daughter cells. Defects in these events are thought to contribute to several human diseases. The underlying mechanisms that function in spindle morphogenesis and positioning remain incompletely defined, however. Here we describe diverse roles for the actin-microtubule cross-linker Shortstop (Shot) in mitotic spindle function in Drosophila. Shot localizes to mitotic spindle poles, and its knockdown results in an unfocused spindle pole morphology and a disruption of proper spindle orientation. Loss of Shot also leads to chromosome congression defects, cell cycle progression delay, and defective chromosome segregation during anaphase. These mitotic errors trigger apoptosis in Drosophila epithelial tissue, and blocking this apoptotic response results in a marked induction of the epithelial–mesenchymal transition marker MMP-1. The actin-binding domain of Shot directly interacts with Actin-related protein-1 (Arp-1), a key component of the Dynein/Dynactin complex. Knockdown of Arp-1 phenocopies Shot loss universally, whereas chemical disruption of F-actin does so selectively. Our work highlights novel roles for Shot in mitosis and suggests a mechanism involving Dynein/Dynactin activation.
Collapse
Affiliation(s)
- Evan B Dewey
- Department of Biology, University of New Mexico, Albuquerque, NM 87131
| | | |
Collapse
|
19
|
Currier MA, Stehn JR, Swain A, Chen D, Hook J, Eiffe E, Heaton A, Brown D, Nartker BA, Eaves DW, Kloss N, Treutlein H, Zeng J, Alieva IB, Dugina VB, Hardeman EC, Gunning PW, Cripe TP. Identification of Cancer-Targeted Tropomyosin Inhibitors and Their Synergy with Microtubule Drugs. Mol Cancer Ther 2017; 16:1555-1565. [PMID: 28522589 DOI: 10.1158/1535-7163.mct-16-0873] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2016] [Revised: 03/30/2017] [Accepted: 05/11/2017] [Indexed: 12/20/2022]
Abstract
Actin filaments, with their associated tropomyosin polymers, and microtubules are dynamic cytoskeletal systems regulating numerous cell functions. While antimicrotubule drugs are well-established, antiactin drugs have been more elusive. We previously targeted actin in cancer cells by inhibiting the function of a tropomyosin isoform enriched in cancer cells, Tpm3.1, using a first-in-class compound, TR100. Here, we screened over 200 other antitropomyosin analogues for anticancer and on-target activity using a series of in vitro cell-based and biochemical assays. ATM-3507 was selected as the new lead based on its ability to disable Tpm3.1-containing filaments, its cytotoxicity potency, and more favorable drug-like characteristics. We tested ATM-3507 and TR100 alone and in combination with antimicrotubule agents against neuroblastoma models in vitro and in vivo Both ATM-3507 and TR100 showed a high degree of synergy in vitro with vinca alkaloid and taxane antimicrotubule agents. In vivo, combination-treated animals bearing human neuroblastoma xenografts treated with antitropomyosin combined with vincristine showed minimal weight loss, a significant and profound regression of tumor growth and improved survival compared with control and either drug alone. Antitropomyosin combined with vincristine resulted in G2-M phase arrest, disruption of mitotic spindle formation, and cellular apoptosis. Our data suggest that small molecules targeting the actin cytoskeleton via tropomyosin sensitize cancer cells to antimicrotubule agents and are tolerated together in vivo This combination warrants further study. Mol Cancer Ther; 16(8); 1555-65. ©2017 AACR.
Collapse
Affiliation(s)
- Mark A Currier
- Center for Childhood Cancer and Blood Diseases, Nationwide Children's Hospital, Columbus, Ohio.,Division of Hematology/Oncology/Blood and Marrow Transplantation, Nationwide Children's Hospital, Columbus, Ohio
| | - Justine R Stehn
- School of Medical Sciences, University of New South Wales Australia, Sydney, New South Wales, Australia.,Novogen Pty Ltd, Hornsby, New South Wales, Australia
| | - Ashleigh Swain
- School of Medical Sciences, University of New South Wales Australia, Sydney, New South Wales, Australia
| | - Duo Chen
- Center for Childhood Cancer and Blood Diseases, Nationwide Children's Hospital, Columbus, Ohio
| | - Jeff Hook
- School of Medical Sciences, University of New South Wales Australia, Sydney, New South Wales, Australia
| | - Eleanor Eiffe
- Novogen Pty Ltd, Hornsby, New South Wales, Australia
| | - Andrew Heaton
- School of Medical Sciences, University of New South Wales Australia, Sydney, New South Wales, Australia.,Novogen Pty Ltd, Hornsby, New South Wales, Australia
| | - David Brown
- School of Medical Sciences, University of New South Wales Australia, Sydney, New South Wales, Australia.,Novogen Pty Ltd, Hornsby, New South Wales, Australia
| | - Brooke A Nartker
- Center for Childhood Cancer and Blood Diseases, Nationwide Children's Hospital, Columbus, Ohio
| | - David W Eaves
- Division of Oncology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio
| | - Nina Kloss
- School of Medical Sciences, University of New South Wales Australia, Sydney, New South Wales, Australia
| | | | - Jun Zeng
- MedChemSoft Solutions, Wheelers Hill, Victoria, Australia
| | - Irina B Alieva
- School of Medical Sciences, University of New South Wales Australia, Sydney, New South Wales, Australia.,Department of Electron Microscopy, A.N. Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, Russia
| | - Vera B Dugina
- School of Medical Sciences, University of New South Wales Australia, Sydney, New South Wales, Australia.,Mathematical Methods in Biology, A.N. Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, Russia
| | - Edna C Hardeman
- School of Medical Sciences, University of New South Wales Australia, Sydney, New South Wales, Australia
| | - Peter W Gunning
- School of Medical Sciences, University of New South Wales Australia, Sydney, New South Wales, Australia
| | - Timothy P Cripe
- Center for Childhood Cancer and Blood Diseases, Nationwide Children's Hospital, Columbus, Ohio. .,Division of Hematology/Oncology/Blood and Marrow Transplantation, Nationwide Children's Hospital, Columbus, Ohio
| |
Collapse
|
20
|
STK16 regulates actin dynamics to control Golgi organization and cell cycle. Sci Rep 2017; 7:44607. [PMID: 28294156 PMCID: PMC5353726 DOI: 10.1038/srep44607] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2016] [Accepted: 02/09/2017] [Indexed: 11/30/2022] Open
Abstract
STK16 is a ubiquitously expressed, myristoylated, and palmitoylated serine/threonine protein kinase with underexplored functions. Recently, it was shown to be involved in cell division but the mechanism remains unclear. Here we found that human STK16 localizes to the Golgi complex throughout the cell cycle and plays important roles in Golgi structure regulation. STK16 knockdown or kinase inhibition disrupts actin polymers and causes fragmented Golgi in cells. In vitro assays show that STK16 directly binds to actin and regulates actin dynamics in a concentration- and kinase activity-dependent way. In addition, STK16 knockdown or kinase inhibition not only delays mitotic entry and prolongs mitosis, but also causes prometaphase and cytokinesis arrest. Therefore, we revealed STK16 as a novel actin binding protein that resides in the Golgi, which regulates actin dynamics to control Golgi structure and participate in cell cycle progression.
Collapse
|
21
|
Po'uha ST, Kavallaris M. Gamma-actin is involved in regulating centrosome function and mitotic progression in cancer cells. Cell Cycle 2016; 14:3908-19. [PMID: 26697841 DOI: 10.1080/15384101.2015.1120920] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Reorganization of the actin cytoskeleton during mitosis is crucial for regulating cell division. A functional role for γ-actin in mitotic arrest induced by the microtubule-targeted agent, paclitaxel, has recently been demonstrated. We hypothesized that γ-actin plays a role in mitosis. Herein, we investigated the effect of γ-actin in mitosis and demonstrated that γ-actin is important in the distribution of β-actin and formation of actin-rich retraction fibers during mitosis. The reduced ability of paclitaxel to induce mitotic arrest as a result of γ-actin depletion was replicated with a range of mitotic inhibitors, suggesting that γ-actin loss reduces the ability of broad classes of anti-mitotic agents to induce mitotic arrest. In addition, partial depletion of γ-actin enhanced centrosome amplification in cancer cells and caused a significant delay in prometaphase/metaphase. This prolonged prometaphase/metaphase arrest was due to mitotic defects such as uncongressed and missegregated chromosomes, and correlated with an increased presence of mitotic spindle abnormalities in the γ-actin depleted cells. Collectively, these results demonstrate a previously unknown role for γ-actin in regulating centrosome function, chromosome alignment and maintenance of mitotic spindle integrity.
Collapse
Affiliation(s)
- Sela T Po'uha
- a Children's Cancer Institute; Lowy Cancer Research Center; University of New South Wales ; Randwick , NSW , Australia
| | - Maria Kavallaris
- a Children's Cancer Institute; Lowy Cancer Research Center; University of New South Wales ; Randwick , NSW , Australia.,b ARC Center of Excellence in Convergent Bio-Nano Science and Technology; Australian Center for Nanomedicine; University of New South Wales ; Sydney , Australia
| |
Collapse
|
22
|
Sandquist JC, Larson ME, Hine KJ. Myosin-10 independently influences mitotic spindle structure and mitotic progression. Cytoskeleton (Hoboken) 2016; 73:351-64. [PMID: 27220038 DOI: 10.1002/cm.21311] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2015] [Revised: 05/17/2016] [Accepted: 05/20/2016] [Indexed: 12/30/2022]
Abstract
The iconic bipolar structure of the mitotic spindle is of extreme importance to proper spindle function. At best, spindle abnormalities result in a delayed mitosis, while worse outcomes include cell death or disease. Recent work has uncovered an important role for the actin-based motor protein myosin-10 in the regulation of spindle structure and function. Here we examine the contribution of the myosin tail homology 4 (MyTH4) domain of the myosin-10 tail to the protein's spindle functions. The MyTH4 domain is known to mediate binding to microtubules and we verify the suspicion that this domain contributes to myosin-10's close association with the spindle. More surprisingly, our data demonstrate that some but not all of myosin-10's spindle functions require microtubule binding. In particular, myosin-10's contribution to spindle pole integrity requires microtubule binding, whereas its contribution to normal mitotic progression does not. This is demonstrated by the observation that dominant negative expression of the wild-type MyTH4 domain produces multipolar spindles and an increased mitotic index, whereas overexpression of a version of the MyTH4 domain harboring point mutations that abrogate microtubule binding results in only the mitotic index phenotype. Our data suggest that myosin-10 helps to control the metaphase to anaphase transition in cells independent of microtubule binding. © 2016 Wiley Periodicals, Inc.
Collapse
Affiliation(s)
- Joshua C Sandquist
- Biology Department, Grinnell College, Grinnell, Iowa.,Department of Zoology, University of Wisconsin-Madison, Madison, Wisconsin
| | - Matthew E Larson
- Program in Cellular and Molecular Biology and the Medical Scientist Training Program, University of Wisconsin-Madison, Madison, Wisconsin
| | - Ken J Hine
- Biology Department, Grinnell College, Grinnell, Iowa
| |
Collapse
|
23
|
Liu J, Ji X, Li Z, Yang X, Wang W, Zhang X. G protein γ subunit 7 induces autophagy and inhibits cell division. Oncotarget 2016; 7:24832-47. [PMID: 27056891 PMCID: PMC5029746 DOI: 10.18632/oncotarget.8559] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2016] [Accepted: 02/28/2016] [Indexed: 11/25/2022] Open
Abstract
GNG7 (G protein γ subunit 7), a subunit of heterotrimeric G protein, is ubiquitously expressed in multiple tissues but is down-regulated in various cancers. Its expression could reduce tumor volume in mice but the mechanism was not clear. Here we show that GNG7 overexpression inhibits cell proliferation and increases cell death. GNG7 level is cell cycle-dependent and it regulates actin cytoskeleton and cell division. In addition, GNG7 is an autophagy inducer, which is the first reported Gγ protein involved in autophagy. GNG7 knockdown reduces Rapamycin and starvation-induced autophagy. Further analysis reveals that GNG7 inhibits MTOR in cells, a central regulator for autophagy and cell proliferation. In conclusion, GNG7 inhibits MTOR pathway to induce autophagy and cell death, inhibits cell division by regulating actin cytoskeleton. These combined effects lead to the antitumor capacity of GNG7.
Collapse
Affiliation(s)
- Juanjuan Liu
- High Magnetic Field Laboratory, Chinese Academy of Sciences, Hefei, Anhui, 230031, P. R. China
- University of Science and Technology of China, Hefei, Anhui, 230036, P. R. China
| | - Xinmiao Ji
- High Magnetic Field Laboratory, Chinese Academy of Sciences, Hefei, Anhui, 230031, P. R. China
| | - Zhiyuan Li
- High Magnetic Field Laboratory, Chinese Academy of Sciences, Hefei, Anhui, 230031, P. R. China
| | - Xingxing Yang
- High Magnetic Field Laboratory, Chinese Academy of Sciences, Hefei, Anhui, 230031, P. R. China
| | - Wenchao Wang
- High Magnetic Field Laboratory, Chinese Academy of Sciences, Hefei, Anhui, 230031, P. R. China
| | - Xin Zhang
- High Magnetic Field Laboratory, Chinese Academy of Sciences, Hefei, Anhui, 230031, P. R. China
| |
Collapse
|
24
|
Vilmos P, Kristó I, Szikora S, Jankovics F, Lukácsovich T, Kari B, Erdélyi M. The actin-binding ERM protein Moesin directly regulates spindle assembly and function during mitosis. Cell Biol Int 2016; 40:696-707. [PMID: 27006187 DOI: 10.1002/cbin.10607] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2015] [Accepted: 03/19/2016] [Indexed: 12/21/2022]
Abstract
Ezrin-Radixin-Moesin proteins are highly conserved, actin-binding cytoskeletal proteins that play an essential role in microvilli formation, T-cell activation, and tumor metastasis by linking actin filaments to the plasma membrane. Recent studies demonstrated that the only Ezrin-Radixin-Moesin protein of Drosophila melanogaster, Moesin, is involved in mitotic spindle function through stabilizing cell shape and microtubules at the cell cortex. We previously observed that Moesin localizes to the mitotic spindle; hence, we tested for the biological significance of this surprising localization and investigated whether it plays a direct role in spindle function. To separate the cortical and spindle functions of Moesin during mitosis we combined cell biological and genetic methods. We used early Drosophila embryos, in which mitosis occurs in the absence of a cell cortex, and found in vivo evidence for the direct requirement of Moesin in mitotic spindle assembly and function. We also found that the accumulation of Moesin precedes the construction of the microtubule spindle, and the fusiform structure formed by Moesin persists even after the microtubules have disassembled.
Collapse
Affiliation(s)
- Péter Vilmos
- Biological Research Center of the Hungarian Academy of Sciences, 6726 Szeged, Temesvári krt. 62., Hungary
| | - Ildikó Kristó
- Biological Research Center of the Hungarian Academy of Sciences, 6726 Szeged, Temesvári krt. 62., Hungary
| | - Szilárd Szikora
- Biological Research Center of the Hungarian Academy of Sciences, 6726 Szeged, Temesvári krt. 62., Hungary
| | - Ferenc Jankovics
- Biological Research Center of the Hungarian Academy of Sciences, 6726 Szeged, Temesvári krt. 62., Hungary
| | - Tamás Lukácsovich
- Department of Developmental and Cell Biology, University of California Irvine, Irvine, CA, 92697, USA
| | - Beáta Kari
- Biological Research Center of the Hungarian Academy of Sciences, 6726 Szeged, Temesvári krt. 62., Hungary
| | - Miklós Erdélyi
- Biological Research Center of the Hungarian Academy of Sciences, 6726 Szeged, Temesvári krt. 62., Hungary
| |
Collapse
|
25
|
Amicis AD, Sanctis SD, Cristofaro SD, Franchini V, Lista F, Regalbuto E, Giovenale E, Gallerano GP, Nenzi P, Bei R, Fantini M, Benvenuto M, Masuelli L, Coluzzi E, Cicia C, Sgura A. Biological effects of in vitro THz radiation exposure in human foetal fibroblasts. MUTATION RESEARCH-GENETIC TOXICOLOGY AND ENVIRONMENTAL MUTAGENESIS 2015; 793:150-60. [DOI: 10.1016/j.mrgentox.2015.06.003] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/04/2015] [Accepted: 06/05/2015] [Indexed: 11/26/2022]
|
26
|
Yamagishi Y, Abe H. Reorganization of actin filaments by ADF/cofilin is involved in formation of microtubule structures during Xenopus oocyte maturation. Mol Biol Cell 2015; 26:4387-400. [PMID: 26424802 PMCID: PMC4666134 DOI: 10.1091/mbc.e15-01-0035] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2015] [Accepted: 09/25/2015] [Indexed: 01/06/2023] Open
Abstract
We examined the reorganization of actin filaments and microtubules during Xenopus oocyte maturation. Surrounding the germinal vesicle (GV) in immature oocytes, the cytoplasmic actin filaments reorganized to accumulate beneath the vegetal side of the GV, where the microtubule-organizing center and transient microtubule array (MTOC-TMA) assembled, just before GV breakdown (GVBD). Immediately after GVBD, both Xenopus ADF/cofilin (XAC) and its phosphatase Slingshot (XSSH) accumulated into the nuclei and intranuclear actin filaments disassembled from the vegetal side with the shrinkage of the GV. As the MTOC-TMA developed well, cytoplasmic actin filaments were retained at the MTOC-TMA base region. Suppression of XAC dephosphorylation by anti-XSSH antibody injection inhibited both actin filament reorganization and proper formation and localization of both the MTOC-TMA and meiotic spindles. Stabilization of actin filaments by phalloidin also inhibited formation of the MTOC-TMA and disassembly of intranuclear actin filaments without affecting nuclear shrinkage. Nocodazole also caused the MTOC-TMA and the cytoplasmic actin filaments at its base region to disappear, which further impeded disassembly of intranuclear actin filaments from the vegetal side. XAC appears to reorganize cytoplasmic actin filaments required for precise assembly of the MTOC and, together with the MTOC-TMA, regulate the intranuclear actin filament disassembly essential for meiotic spindle formation.
Collapse
Affiliation(s)
- Yuka Yamagishi
- Department of Nanobiology, Graduate School of Advanced Integration Science, Chiba University, Chiba 263-8522, Japan
| | - Hiroshi Abe
- Department of Nanobiology, Graduate School of Advanced Integration Science, Chiba University, Chiba 263-8522, Japan
| |
Collapse
|
27
|
Direct Microtubule-Binding by Myosin-10 Orients Centrosomes toward Retraction Fibers and Subcortical Actin Clouds. Dev Cell 2015; 34:323-37. [PMID: 26235048 DOI: 10.1016/j.devcel.2015.06.013] [Citation(s) in RCA: 77] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2014] [Revised: 04/08/2015] [Accepted: 06/12/2015] [Indexed: 11/21/2022]
Abstract
Positioning of centrosomes is vital for cell division and development. In metazoan cells, spindle positioning is controlled by a dynamic pool of subcortical actin that organizes in response to the position of retraction fibers. These actin "clouds" are proposed to generate pulling forces on centrosomes and mediate spindle orientation. However, the motors that pull astral microtubules toward these actin structures are not known. Here, we report that the unconventional myosin, Myo10, couples actin-dependent forces from retraction fibers and subcortical actin clouds to centrosomes. Myo10-mediated centrosome positioning requires its direct microtubule binding. Computational image analysis of large microtubule populations reveals a direct effect of Myo10 on microtubule dynamics and microtubule-cortex interactions. Myo10's role in centrosome positioning is distinct from, but overlaps with, that of dynein. Thus, Myo10 plays a key role in integrating the actin and microtubule cytoskeletons to position centrosomes and mitotic spindles.
Collapse
|
28
|
Goins LM, Mullins RD. A novel tropomyosin isoform functions at the mitotic spindle and Golgi in Drosophila. Mol Biol Cell 2015; 26:2491-504. [PMID: 25971803 PMCID: PMC4571303 DOI: 10.1091/mbc.e14-12-1619] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2014] [Accepted: 05/05/2015] [Indexed: 12/28/2022] Open
Abstract
Most eukaryotic cells express multiple isoforms of the actin-binding protein tropomyosin that help construct a variety of cytoskeletal networks. Only one nonmuscle tropomyosin (Tm1A) has previously been described in Drosophila, but developmental defects caused by insertion of P-elements near tropomyosin genes imply the existence of additional, nonmuscle isoforms. Using biochemical and molecular genetic approaches, we identified three tropomyosins expressed in Drosophila S2 cells: Tm1A, Tm1J, and Tm2A. The Tm1A isoform localizes to the cell cortex, lamellar actin networks, and the cleavage furrow of dividing cells--always together with myosin-II. Isoforms Tm1J and Tm2A colocalize around the Golgi apparatus with the formin-family protein Diaphanous, and loss of either isoform perturbs cell cycle progression. During mitosis, Tm1J localizes to the mitotic spindle, where it promotes chromosome segregation. Using chimeras, we identified the determinants of tropomyosin localization near the C-terminus. This work 1) identifies and characterizes previously unknown nonmuscle tropomyosins in Drosophila, 2) reveals a function for tropomyosin in the mitotic spindle, and 3) uncovers sequence elements that specify isoform-specific localizations and functions of tropomyosin.
Collapse
Affiliation(s)
- Lauren M Goins
- Department of Cellular and Molecular Pharmacology, School of Medicine, University of California, San Francisco, San Francisco, CA 94158
| | - R Dyche Mullins
- Department of Cellular and Molecular Pharmacology, School of Medicine, University of California, San Francisco, San Francisco, CA 94158
| |
Collapse
|
29
|
Forer A, Johansen KM, Johansen J. Movement of chromosomes with severed kinetochore microtubules. PROTOPLASMA 2015; 252:775-781. [PMID: 25576435 DOI: 10.1007/s00709-014-0752-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/12/2014] [Accepted: 12/17/2014] [Indexed: 06/04/2023]
Abstract
Experiments dating from 1966 and thereafter showed that anaphase chromosomes continued to move poleward after their kinetochore microtubules were severed by ultraviolet microbeam irradiation. These observations were initially met with scepticism as they contradicted the prevailing view that kinetochore fibre microtubules pulled chromosomes to the pole. However, recent experiments using visible light laser microbeam irradiations have corroborated these earlier experiments as anaphase chromosomes again were shown to move poleward after their kinetochore microtubules were severed. Thus, multiple independent studies using different techniques have shown that chromosomes can indeed move poleward without direct microtubule connections to the pole, with only a kinetochore 'stub' of microtubules. An issue not yet settled is: what propels the disconnected chromosome? There are two not necessarily mutually exclusive proposals in the literature: (1) chromosome movement is propelled by the kinetochore stub interacting with non-kinetochore microtubules and (2) chromosome movement is propelled by a spindle matrix acting on the stub. In this review, we summarise the data indicating that chromosomes can move with severed kinetochore microtubules and we discuss proposed mechanisms for chromosome movement with severed kinetochore microtubules.
Collapse
Affiliation(s)
- Arthur Forer
- Biology Department, York University, North York, Ontario, M3J 1P3, Canada,
| | | | | |
Collapse
|
30
|
Deshpande S, Pfohl T. Real-time dynamics of emerging actin networks in cell-mimicking compartments. PLoS One 2015; 10:e0116521. [PMID: 25785606 PMCID: PMC4364982 DOI: 10.1371/journal.pone.0116521] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2014] [Accepted: 12/10/2014] [Indexed: 01/07/2023] Open
Abstract
Understanding the cytoskeletal functionality and its relation to other cellular components and properties is a prominent question in biophysics. The dynamics of actin cytoskeleton and its polymorphic nature are indispensable for the proper functioning of living cells. Actin bundles are involved in cell motility, environmental exploration, intracellular transport and mechanical stability. Though the viscoelastic properties of actin-based structures have been extensively probed, the underlying microstructure dynamics, especially their disassembly, is not fully understood. In this article, we explore the rich dynamics and emergent properties exhibited by actin bundles within flow-free confinements using a microfluidic set-up and epifluorescence microscopy. After forming entangled actin filaments within cell-sized quasi two-dimensional confinements, we induce their bundling using three different fundamental mechanisms: counterion condensation, depletion interactions and specific protein-protein interactions. Intriguingly, long actin filaments form emerging networks of actin bundles via percolation leading to remarkable properties such as stress generation and spindle-like intermediate structures. Simultaneous sharing of filaments in different links of the network is an important parameter, as short filaments do not form networks but segregated clusters of bundles instead. We encounter a hierarchical process of bundling and its subsequent disassembly. Additionally, our study suggests that such percolated networks are likely to exist within living cells in a dynamic fashion. These observations render a perspective about differential cytoskeletal responses towards numerous stimuli.
Collapse
Affiliation(s)
- Siddharth Deshpande
- Department of Chemistry, University of Basel, Klingelbergstrasse 80, CH-4056 Basel, Switzerland
| | - Thomas Pfohl
- Department of Chemistry, University of Basel, Klingelbergstrasse 80, CH-4056 Basel, Switzerland
| |
Collapse
|
31
|
Lu H, Zhao Q, Jiang H, Zhu T, Xia P, Seffens W, Aikhionbare F, Wang D, Dou Z, Yao X. Characterization of ring-like F-actin structure as a mechanical partner for spindle positioning in mitosis. PLoS One 2014; 9:e102547. [PMID: 25299690 PMCID: PMC4191959 DOI: 10.1371/journal.pone.0102547] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2014] [Accepted: 06/19/2014] [Indexed: 01/03/2023] Open
Abstract
Proper spindle positioning and orientation are essential for accurate mitosis which requires dynamic interactions between microtubule and actin filament (F-actin). Although mounting evidence demonstrates the role of F-actin in cortical cytoskeleton dynamics, it remains elusive as to the structure and function of F-actin-based networks in spindle geometry. Here we showed a ring-like F-actin structure surrounding the mitotic spindle which forms since metaphase and maintains in MG132-arrested metaphase HeLa cells. This cytoplasmic F-actin structure is relatively isotropic and less dynamic. Our computational modeling of spindle position process suggests a possible mechanism by which the ring-like F-actin structure can regulate astral microtubule dynamics and thus mitotic spindle orientation. We further demonstrated that inhibiting Plk1, Mps1 or Myosin, and disruption of microtubules or F-actin polymerization perturbs the formation of the ring-like F-actin structure and alters spindle position and symmetric division. These findings reveal a previously unrecognized but important link between mitotic spindle and ring-like F-actin network in accurate mitosis and enables the development of a method to theoretically illustrate the relationship between mitotic spindle and cytoplasmic F-actin.
Collapse
Affiliation(s)
- Huan Lu
- Anhui Key Laboratory of Cellular Dynamics and Chemical Biology, University of Science and Technology of China, Hefei, Anhui, China
| | - Qun Zhao
- Anhui Key Laboratory of Cellular Dynamics and Chemical Biology, University of Science and Technology of China, Hefei, Anhui, China
| | - Hao Jiang
- Anhui Key Laboratory of Cellular Dynamics and Chemical Biology, University of Science and Technology of China, Hefei, Anhui, China
| | - Tongge Zhu
- Anhui Key Laboratory of Cellular Dynamics and Chemical Biology, University of Science and Technology of China, Hefei, Anhui, China
- Department of Physiology, Morehouse School of Medicine, Atlanta, Georgia, United States of America
| | - Peng Xia
- Anhui Key Laboratory of Cellular Dynamics and Chemical Biology, University of Science and Technology of China, Hefei, Anhui, China
| | - William Seffens
- Department of Physiology, Morehouse School of Medicine, Atlanta, Georgia, United States of America
| | - Felix Aikhionbare
- Department of Physiology, Morehouse School of Medicine, Atlanta, Georgia, United States of America
| | - Dongmei Wang
- Anhui Key Laboratory of Cellular Dynamics and Chemical Biology, University of Science and Technology of China, Hefei, Anhui, China
| | - Zhen Dou
- Anhui Key Laboratory of Cellular Dynamics and Chemical Biology, University of Science and Technology of China, Hefei, Anhui, China
| | - Xuebiao Yao
- Anhui Key Laboratory of Cellular Dynamics and Chemical Biology, University of Science and Technology of China, Hefei, Anhui, China
- * E-mail:
| |
Collapse
|
32
|
Moorhouse KS, Burgess DR. How to be at the right place at the right time: the importance of spindle positioning in embryos. Mol Reprod Dev 2014; 81:884-95. [PMID: 25258000 DOI: 10.1002/mrd.22418] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2014] [Accepted: 08/26/2014] [Indexed: 01/03/2023]
Abstract
Spindle positioning is an imperative cellular process that regulates a number of different developmental events throughout embryogenesis. The spindle must be properly positioned in embryos not only for the segregation of chromosomes, but also to segregate developmental determinants into different daughter blastomeres. In this review, the role of spindle positioning is explored in several different developmental model systems, which have revealed the diversity of factors that regulate spindle positioning. The C. elegans embryo, the Drosophila neuroblast, and ascidian embryos have all been utilized for the study of polarity-dependent spindle positioning, and exploration of the proteins that are required for asymmetric cell division. Work in the sea urchin embryo has examined the influence of cell shape and factors that affect secondary furrow formation. The issue of size scaling in extremely large cells, as well as the requirement for spindle positioning in developmental fate decisions in vertebrates, has been addressed by work in the Xenopus embryo. Further work in mouse oocytes has examined the roles of actin and myosin in spindle positioning. The data generated from these model organisms have made unique contributions to our knowledge of spindle positioning. Future work will address how all of these different factors work together to regulate the position of the spindle.
Collapse
|
33
|
Machicoane M, de Frutos CA, Fink J, Rocancourt M, Lombardi Y, Garel S, Piel M, Echard A. SLK-dependent activation of ERMs controls LGN-NuMA localization and spindle orientation. ACTA ACUST UNITED AC 2014; 205:791-9. [PMID: 24958772 PMCID: PMC4068135 DOI: 10.1083/jcb.201401049] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
ERM activation by SLK kinase promotes polarized association at the mitotic cortex of LGN and NuMA, a necessary step in proper spindle orientation. Mitotic spindle orientation relies on a complex dialog between the spindle microtubules and the cell cortex, in which F-actin has been recently implicated. Here, we report that the membrane–actin linkers ezrin/radixin/moesin (ERMs) are strongly and directly activated by the Ste20-like kinase at mitotic entry in mammalian cells. Using microfabricated adhesive substrates to control the axis of cell division, we found that the activation of ERMs plays a key role in guiding the orientation of the mitotic spindle. Accordingly, impairing ERM activation in apical progenitors of the mouse embryonic neocortex severely disturbed spindle orientation in vivo. At the molecular level, ERM activation promotes the polarized association at the mitotic cortex of leucine-glycine-asparagine repeat protein (LGN) and nuclear mitotic apparatus (NuMA) protein, two essential factors for spindle orientation. We propose that activated ERMs, together with Gαi, are critical for the correct localization of LGN–NuMA force generator complexes and hence for proper spindle orientation.
Collapse
Affiliation(s)
- Mickael Machicoane
- Membrane Traffic and Cell Division Laboratory, Institut Pasteur, 75015 Paris, France Centre National de la Recherche Scientifique URA2582, 75015 Paris, France Sorbonne Universités, Université Pierre et Marie Curie, Université Paris 06, Institut de formation doctorale, 75252 Paris, France
| | - Cristina A de Frutos
- Institut de Biologie de L'Ecole Normale Supérieure, Ecole Normale Supérieure, 75005 Paris, France Institut National de la Santé et de la Recherche Médicale, U1024, Centre National de la Recherche Scientifique UMR8197, 75005 Paris, France
| | - Jenny Fink
- Systems Cell Biology of Cell Polarity and Cell Division Laboratory, Institut Curie, 75005 Paris, France Centre National de la Recherche Scientifique UMR144, 75005 Paris, France
| | - Murielle Rocancourt
- Membrane Traffic and Cell Division Laboratory, Institut Pasteur, 75015 Paris, France Centre National de la Recherche Scientifique URA2582, 75015 Paris, France
| | - Yannis Lombardi
- Membrane Traffic and Cell Division Laboratory, Institut Pasteur, 75015 Paris, France Centre National de la Recherche Scientifique URA2582, 75015 Paris, France
| | - Sonia Garel
- Institut de Biologie de L'Ecole Normale Supérieure, Ecole Normale Supérieure, 75005 Paris, France Institut National de la Santé et de la Recherche Médicale, U1024, Centre National de la Recherche Scientifique UMR8197, 75005 Paris, France
| | - Matthieu Piel
- Systems Cell Biology of Cell Polarity and Cell Division Laboratory, Institut Curie, 75005 Paris, France Centre National de la Recherche Scientifique UMR144, 75005 Paris, France
| | - Arnaud Echard
- Membrane Traffic and Cell Division Laboratory, Institut Pasteur, 75015 Paris, France Centre National de la Recherche Scientifique URA2582, 75015 Paris, France
| |
Collapse
|
34
|
Lancaster OM, Baum B. Shaping up to divide: coordinating actin and microtubule cytoskeletal remodelling during mitosis. Semin Cell Dev Biol 2014; 34:109-15. [PMID: 24607328 DOI: 10.1016/j.semcdb.2014.02.015] [Citation(s) in RCA: 72] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2014] [Accepted: 02/26/2014] [Indexed: 10/25/2022]
Abstract
Cell division requires the wholesale reorganization of cell architecture. At the same time as the microtubule network is remodelled to generate a bipolar spindle, animal cells entering mitosis replace their interphase actin cytoskeleton with a contractile mitotic actomyosin cortex that is tightly coupled to the plasma membrane--driving mitotic cell rounding. Here, we consider how these two processes are coordinated to couple chromosome segregation and cell division. In doing so we explore the relative roles of cell shape and the actin cortex in spindle morphogenesis, orientation and positioning.
Collapse
Affiliation(s)
- Oscar M Lancaster
- MRC Laboratory for Molecular Cell Biology, University College London, Gower Street, London WC1E 6BT, UK.
| | - Buzz Baum
- MRC Laboratory for Molecular Cell Biology, University College London, Gower Street, London WC1E 6BT, UK.
| |
Collapse
|
35
|
Caballero-Lima D, Sudbery PE. In Candida albicans, phosphorylation of Exo84 by Cdk1-Hgc1 is necessary for efficient hyphal extension. Mol Biol Cell 2014; 25:1097-110. [PMID: 24501427 PMCID: PMC3967973 DOI: 10.1091/mbc.e13-11-0688] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Candida albicans hyphae continue to grow throughout mitosis, and phosphorylation of Exo84 by Cdk is necessary for efficient hyphal growth. In contrast, phosphorylation of Exo84 by Cdk halts cell growth in Saccharomyces cerevisiae. The location of Cdk1 target sites in Exo84 explains how phosphoregulation mediates these different patterns of growth. The exocyst, a conserved multiprotein complex, tethers secretory vesicles before fusion with the plasma membrane; thus it is essential for cell surface expansion. In both Saccharomyces cerevisiae and mammalian cells, cell surface expansion is halted during mitosis. In S. cerevisiae, phosphorylation of the exocyst component Exo84 by Cdk1-Clb2 during mitosis causes the exocyst to disassemble. Here we show that the hyphae of the human fungal pathogen Candida albicans continue to extend throughout the whole of mitosis. We show that CaExo84 is phosphorylated by Cdk1, which is necessary for efficient hyphal extension. This action of Cdk1 depends on the hyphal-specific cyclin Hgc1, the homologue of G1 cyclins in budding yeast. Phosphorylation of CaExo84 does not alter its localization but does alter its affinity for phosphatidylserine, allowing it to recycle at the plasma membrane. The different action of Cdk1 on CaExo84 and ScExo84 is consistent with the different locations of the Cdk1 target sites in the two proteins. Thus this conserved component of polarized growth has evolved so that its phosphoregulation mediates the dramatically different patterns of growth shown by these two organisms.
Collapse
Affiliation(s)
- David Caballero-Lima
- Department of Molecular Biology and Biotechnology, University of Sheffield, Western Bank, Sheffield S10 2TN, United Kingdom
| | | |
Collapse
|
36
|
Epithelial junctions maintain tissue architecture by directing planar spindle orientation. Nature 2013; 500:359-62. [PMID: 23873041 DOI: 10.1038/nature12335] [Citation(s) in RCA: 147] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2012] [Accepted: 05/24/2013] [Indexed: 02/07/2023]
Abstract
During epithelial cell proliferation, planar alignment of the mitotic spindle coordinates the local process of symmetric cell cleavage with the global maintenance of polarized tissue architecture. Although the disruption of planar spindle alignment is proposed to cause epithelial to mesenchymal transition and cancer, the in vivo mechanisms regulating mitotic spindle orientation remain elusive. Here we demonstrate that the actomyosin cortex and the junction-localized neoplastic tumour suppressors Scribbled and Discs large 1 have essential roles in planar spindle alignment and thus the control of epithelial integrity in the Drosophila imaginal disc. We show that defective alignment of the mitotic spindle correlates with cell delamination and apoptotic death, and that blocking the death of misaligned cells is sufficient to drive the formation of basally localized tumour-like masses. These findings indicate a key role for junction-mediated spindle alignment in the maintenance of epithelial integrity, and also reveal a previously unknown cell-death-mediated tumour-suppressor function inherent in the polarized architecture of epithelia.
Collapse
|
37
|
Mitotic rounding alters cell geometry to ensure efficient bipolar spindle formation. Dev Cell 2013; 25:270-83. [PMID: 23623611 DOI: 10.1016/j.devcel.2013.03.014] [Citation(s) in RCA: 213] [Impact Index Per Article: 19.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2012] [Revised: 02/14/2013] [Accepted: 03/21/2013] [Indexed: 01/07/2023]
Abstract
Accurate animal cell division requires precise coordination of changes in the structure of the microtubule-based spindle and the actin-based cell cortex. Here, we use a series of perturbation experiments to dissect the relative roles of actin, cortical mechanics, and cell shape in spindle formation. We find that, whereas the actin cortex is largely dispensable for rounding and timely mitotic progression in isolated cells, it is needed to drive rounding to enable unperturbed spindle morphogenesis under conditions of confinement. Using different methods to limit mitotic cell height, we show that a failure to round up causes defects in spindle assembly, pole splitting, and a delay in mitotic progression. These defects can be rescued by increasing microtubule lengths and therefore appear to be a direct consequence of the limited reach of mitotic centrosome-nucleated microtubules. These findings help to explain why most animal cells round up as they enter mitosis.
Collapse
|
38
|
Iwase S, Sato R, De Bock PJ, Gevaert K, Fujiki S, Tawada T, Kuchitsu M, Yamagishi Y, Ono S, Abe H. Activation of ADF/cofilin by phosphorylation-regulated Slingshot phosphatase is required for the meiotic spindle assembly in Xenopus laevis oocytes. Mol Biol Cell 2013; 24:1933-46. [PMID: 23615437 PMCID: PMC3681698 DOI: 10.1091/mbc.e12-12-0851] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
We identify Xenopus ADF/cofilin (XAC) and its activator, Slingshot phosphatase (XSSH), as key regulators of actin dynamics essential for spindle microtubule assembly during Xenopus oocyte maturation. Phosphorylation of XSSH at multiple sites within the tail domain occurs just after germinal vesicle breakdown (GVBD) and is accompanied by dephosphorylation of XAC, which was mostly phosphorylated in immature oocytes. This XAC dephosphorylation after GVBD is completely suppressed by latrunculin B, an actin monomer-sequestering drug. On the other hand, jasplakinolide, an F-actin-stabilizing drug, induces dephosphorylation of XAC. Effects of latrunculin B and jasplakinolide are reconstituted in cytostatic factor-arrested extracts (CSF extracts), and XAC dephosphorylation is abolished by depletion of XSSH from CSF extracts, suggesting that XSSH functions as an actin filament sensor to facilitate actin filament dynamics via XAC activation. Injection of anti-XSSH antibody, which blocks full phosphorylation of XSSH after GVBD, inhibits both meiotic spindle formation and XAC dephosphorylation. Coinjection of constitutively active XAC with the antibody suppresses this phenotype. Treatment of oocytes with jasplakinolide also impairs spindle formation. These results strongly suggest that elevation of actin dynamics by XAC activation through XSSH phosphorylation is required for meiotic spindle assembly in Xenopus laevis.
Collapse
Affiliation(s)
- Shohei Iwase
- Department of Nanobiology, Graduate School of Advanced Integration Science, Chiba University, Chiba 263-8522, Japan
| | | | | | | | | | | | | | | | | | | |
Collapse
|
39
|
Sheykhani R, Baker N, Gomez-Godinez V, Liaw LH, Shah J, Berns MW, Forer A. The role of actin and myosin in PtK2 spindle length changes induced by laser microbeam irradiations across the spindle. Cytoskeleton (Hoboken) 2013; 70:241-59. [PMID: 23475753 DOI: 10.1002/cm.21104] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2012] [Revised: 02/07/2013] [Accepted: 02/20/2013] [Indexed: 11/08/2022]
Abstract
This study investigates spindle biomechanical properties to better understand how spindles function. In this report, laser microbeam cutting across mitotic spindles resulted in movement of spindle poles toward the spindle equator. The pole on the cut side moved first, the other pole moved later, resulting in a shorter but symmetric spindle. Intervening spindle microtubules bent and buckled during the equatorial movement of the poles. Because of this and because there were no detectable microtubules within the ablation zone, other cytoskeletal elements would seem to be involved in the equatorial movement of the poles. One possibility is actin and myosin since pharmacological poisoning of the actin-myosin system altered the equatorial movements of both irradiated and unirradiated poles. Immunofluorescence microscopy confirmed that actin, myosin and monophosphorylated myosin are associated with spindle fibers and showed that some actin and monophosphorylated myosin remained in the irradiated regions. Overall, our experiments suggest that actin, myosin and microtubules interact to control spindle length. We suggest that actin and myosin, possibly in conjunction with the spindle matrix, cause the irradiated pole to move toward the equator and that cross-talk between the two half spindles causes the unirradiated pole to move toward the equator until a balanced length is obtained.
Collapse
Affiliation(s)
- Rozhan Sheykhani
- Department of Biology, York University, Toronto, Ontario, Canada
| | | | | | | | | | | | | |
Collapse
|
40
|
Sheykhani R, Shirodkar PV, Forer A. The role of myosin phosphorylation in anaphase chromosome movement. Eur J Cell Biol 2013; 92:175-86. [PMID: 23566798 DOI: 10.1016/j.ejcb.2013.02.002] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2012] [Revised: 01/26/2013] [Accepted: 02/22/2013] [Indexed: 11/29/2022] Open
Abstract
This work deals with the role of myosin phosphorylation in anaphase chromosome movement. Y27632 and ML7 block two different pathways for phosphorylation of the myosin regulatory light chain (MRLC). Both stopped or slowed chromosome movement when added to anaphase crane-fly spermatocytes. To confirm that the effects of the pharmacological agents were on the presumed targets, we studied cells stained with antibodies against mono- or bi-phosphorylated myosin. For all chromosomes whose movements were affected by a drug, the corresponding spindle fibres of the affected chromosomes had reduced levels of 1P- and 2P-myosin. Thus the drugs acted on the presumed target and myosin phosphorylation is involved in anaphase force production. Calyculin A, an inhibitor of MRLC dephosphorylation, reversed and accelerated the altered movements caused by Y27632 and ML-7, suggesting that another phosphorylation pathway is involved in phosphorylation of spindle myosin. Staurosporine, a more general phosphorylation inhibitor, also reduced the levels of MRLC phosphorylation and caused anaphase chromosomes to stop or slow. The effects of staurosporine on chromosome movements were not reversed by Calyculin A, confirming that another phosphorylation pathway is involved in phosphorylation of spindle myosin.
Collapse
Affiliation(s)
- Rozhan Sheykhani
- Department of Biology, York University, Toronto, Ontario M3J 1P3, Canada
| | | | | |
Collapse
|
41
|
Hebert AM, DuBoff B, Casaletto JB, Gladden AB, McClatchey AI. Merlin/ERM proteins establish cortical asymmetry and centrosome position. Genes Dev 2013; 26:2709-23. [PMID: 23249734 DOI: 10.1101/gad.194027.112] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
The ability to generate asymmetry at the cell cortex underlies cell polarization and asymmetric cell division. Here we demonstrate a novel role for the tumor suppressor Merlin and closely related ERM proteins (Ezrin, Radixin, and Moesin) in generating cortical asymmetry in the absence of external cues. Our data reveal that Merlin functions to restrict the cortical distribution of the actin regulator Ezrin, which in turn positions the interphase centrosome in single epithelial cells and three-dimensional organotypic cultures. In the absence of Merlin, ectopic cortical Ezrin yields mispositioned centrosomes, misoriented spindles, and aberrant epithelial architecture. Furthermore, in tumor cells with centrosome amplification, the failure to restrict cortical Ezrin abolishes centrosome clustering, yielding multipolar mitoses. These data uncover fundamental roles for Merlin/ERM proteins in spatiotemporally organizing the cell cortex and suggest that Merlin's role in restricting cortical Ezrin may contribute to tumorigenesis by disrupting cell polarity, spindle orientation, and, potentially, genome stability.
Collapse
Affiliation(s)
- Alan M Hebert
- Massachusetts General Hospital Center for Cancer Research, Charlestown, Massachusetts 02129, USA
| | | | | | | | | |
Collapse
|
42
|
Yao C, Rath U, Maiato H, Sharp D, Girton J, Johansen KM, Johansen J. A nuclear-derived proteinaceous matrix embeds the microtubule spindle apparatus during mitosis. Mol Biol Cell 2012; 23:3532-41. [PMID: 22855526 PMCID: PMC3442402 DOI: 10.1091/mbc.e12-06-0429] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2012] [Revised: 07/12/2012] [Accepted: 07/26/2012] [Indexed: 01/03/2023] Open
Abstract
The concept of a spindle matrix has long been proposed. Whether such a structure exists, however, and what its molecular and structural composition are have remained controversial. In this study, using a live-imaging approach in Drosophila syncytial embryos, we demonstrate that nuclear proteins reorganize during mitosis to form a highly dynamic, viscous spindle matrix that embeds the microtubule spindle apparatus, stretching from pole to pole. We show that this "internal" matrix is a distinct structure from the microtubule spindle and from a lamin B-containing spindle envelope. By injection of 2000-kDa dextran, we show that the disassembling nuclear envelope does not present a diffusion barrier. Furthermore, when microtubules are depolymerized with colchicine just before metaphase the spindle matrix contracts and coalesces around the chromosomes, suggesting that microtubules act as "struts" stretching the spindle matrix. In addition, we demonstrate that the spindle matrix protein Megator requires its coiled-coil amino-terminal domain for spindle matrix localization, suggesting that specific interactions between spindle matrix molecules are necessary for them to form a complex confined to the spindle region. The demonstration of an embedding spindle matrix lays the groundwork for a more complete understanding of microtubule dynamics and of the viscoelastic properties of the spindle during cell division.
Collapse
Affiliation(s)
- Changfu Yao
- Department of Biochemistry, Biophysics, and Molecular Biology, Iowa State University, Ames, IA 50011
| | - Uttama Rath
- Department of Physiology and Biophysics, Albert Einstein College of Medicine, Bronx, NY 10461
| | - Helder Maiato
- Instituto de Biologia Molecular e Celular, Universidade do Porto, 4150-180 Porto, Portugal
| | - David Sharp
- Department of Physiology and Biophysics, Albert Einstein College of Medicine, Bronx, NY 10461
| | - Jack Girton
- Department of Biochemistry, Biophysics, and Molecular Biology, Iowa State University, Ames, IA 50011
| | - Kristen M. Johansen
- Department of Biochemistry, Biophysics, and Molecular Biology, Iowa State University, Ames, IA 50011
| | - Jørgen Johansen
- Department of Biochemistry, Biophysics, and Molecular Biology, Iowa State University, Ames, IA 50011
| |
Collapse
|
43
|
Spindle orientation in mammalian cerebral cortical development. Curr Opin Neurobiol 2012; 22:737-46. [PMID: 22554882 PMCID: PMC3500682 DOI: 10.1016/j.conb.2012.04.003] [Citation(s) in RCA: 116] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2012] [Accepted: 04/07/2012] [Indexed: 12/24/2022]
Abstract
In any mitotic cell, the orientation of the mitotic spindle determines the orientation of the cleavage plane and therefore the position of the two daughter cells. When combined with polarization of cellular components, spindle orientation is also a well-conserved means of generating daughter cells with asymmetric cell fates, such as progenitors and differentiated cell types. In the mammalian neocortex, the precise planar spindle orientation observed early during development is vital for symmetric proliferative divisions. During later stages, spindles can be oblique or even vertical but the role of this reorientation is somewhat less clear as asymmetric cell fates can arise independently of spindle orientation during this stage. Although decades of work have identified many key conserved regulators of spindle positioning, its precise role in cell fate determination in the mammalian neocortex has been enigmatic. Recent work focused on mInsc and LGN has now revealed an important role for spindle orientation in determination of specific asymmetric cell fates, namely intermediate progenitors and a new progenitor population, termed outer radial glia. In this way, spindle orientation helps determine the neurogenic outcome of asymmetric progenitor divisions, thereby influencing neuron output and cerebral cortical expansion.
Collapse
|
44
|
Walsh CJ. The structure of the mitotic spindle and nucleolus during mitosis in the amebo-flagellate Naegleria. PLoS One 2012; 7:e34763. [PMID: 22493714 PMCID: PMC3321029 DOI: 10.1371/journal.pone.0034763] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2011] [Accepted: 03/05/2012] [Indexed: 11/24/2022] Open
Abstract
Mitosis in the amebo-flagellate Naegleria pringsheimi is acentrosomal and closed (the nuclear membrane does not break down). The large central nucleolus, which occupies about 20% of the nuclear volume, persists throughout the cell cycle. At mitosis, the nucleolus divides and moves to the poles in association with the chromosomes. The structure of the mitotic spindle and its relationship to the nucleolus are unknown. To identify the origin and structure of the mitotic spindle, its relationship to the nucleolus and to further understand the influence of persistent nucleoli on cellular division in acentriolar organisms like Naegleria, three-dimensional reconstructions of the mitotic spindle and nucleolus were carried out using confocal microscopy. Monoclonal antibodies against three different nucleolar regions and α-tubulin were used to image the nucleolus and mitotic spindle. Microtubules were restricted to the nucleolus beginning with the earliest prophase spindle microtubules. Early spindle microtubules were seen as short rods on the surface of the nucleolus. Elongation of the spindle microtubules resulted in a rough cage of microtubules surrounding the nucleolus. At metaphase, the mitotic spindle formed a broad band completely embedded within the nucleolus. The nucleolus separated into two discreet masses connected by a dense band of microtubules as the spindle elongated. At telophase, the distal ends of the mitotic spindle were still completely embedded within the daughter nucleoli. Pixel by pixel comparison of tubulin and nucleolar protein fluorescence showed 70% or more of tubulin co-localized with nucleolar proteins by early prophase. These observations suggest a model in which specific nucleolar binding sites for microtubules allow mitotic spindle formation and attachment. The fact that a significant mass of nucleolar material precedes the chromosomes as the mitotic spindle elongates suggests that spindle elongation drives nucleolar division.
Collapse
Affiliation(s)
- Charles J Walsh
- Department of Biological Science, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America.
| |
Collapse
|
45
|
Spindle position in symmetric cell divisions during epiboly is controlled by opposing and dynamic apicobasal forces. Dev Cell 2012; 22:775-87. [PMID: 22406140 PMCID: PMC3332010 DOI: 10.1016/j.devcel.2012.01.002] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2011] [Revised: 11/08/2011] [Accepted: 01/11/2012] [Indexed: 11/21/2022]
Abstract
Orientation of cell division is a vital aspect of tissue morphogenesis and growth. Asymmetric divisions generate cell fate diversity and epithelial stratification, whereas symmetric divisions contribute to tissue growth, spreading, and elongation. Here, we describe a mechanism for positioning the spindle in symmetric cell divisions of an embryonic epithelium. We show that during the early stages of epiboly, spindles in the epithelium display dynamic behavior within the plane of the epithelium but are kept firmly within this plane to give a symmetric division. This dynamic stability relies on balancing counteracting forces: an apically directed force exerted by F-actin/myosin-2 via active cortical flow and a basally directed force mediated by microtubules and myosin-10. When both forces are disrupted, spindle orientation deviates from the epithelial plane, and epithelial surface is reduced. We propose that this dynamic mechanism maintains symmetric divisions while allowing the quick adjustment of division plane to facilitate even tissue spreading.
Collapse
|
46
|
Spindle positioning in mammalian oocytes. Exp Cell Res 2012; 318:1442-7. [PMID: 22406266 DOI: 10.1016/j.yexcr.2012.02.019] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2011] [Revised: 02/21/2012] [Accepted: 02/22/2012] [Indexed: 11/22/2022]
Abstract
To preserve the maternal stores accumulated during oogenesis for further embryo development, oocytes divide asymmetrically which minimizes the volume of cytoplasm lost with each set of haploid genome. To ensure asymmetric division to occur, oocytes have to position their division spindle asymmetrically as well as tailor the size of daughter cells to the chromatin mass. In this review, we will discuss the recent advances in the field, with emphasis on the control mechanisms involved in meiotic spindle positioning in mammalian oocytes.
Collapse
|