1
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Middelkoop TC, Neipel J, Cornell CE, Naumann R, Pimpale LG, Jülicher F, Grill SW. A cytokinetic ring-driven cell rotation achieves Hertwig's rule in early development. Proc Natl Acad Sci U S A 2024; 121:e2318838121. [PMID: 38870057 PMCID: PMC11194556 DOI: 10.1073/pnas.2318838121] [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: 10/30/2023] [Accepted: 05/03/2024] [Indexed: 06/15/2024] Open
Abstract
Hertwig's rule states that cells divide along their longest axis, usually driven by forces acting on the mitotic spindle. Here, we show that in contrast to this rule, microtubule-based pulling forces in early Caenorhabditis elegans embryos align the spindle with the short axis of the cell. We combine theory with experiments to reveal that in order to correct this misalignment, inward forces generated by the constricting cytokinetic ring rotate the entire cell until the spindle is aligned with the cell's long axis. Experiments with slightly compressed mouse zygotes indicate that this cytokinetic ring-driven mechanism of ensuring Hertwig's rule is general for cells capable of rotating inside a confining shell, a scenario that applies to early cell divisions of many systems.
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Affiliation(s)
- Teije C. Middelkoop
- Max Planck Institute of Molecular Cell Biology and Genetics, 01307Dresden, Germany
- Laboratory of Developmental Mechanobiology, Division Biocev, Institute of Molecular Genetics of the Czech Academy of Sciences, 14220Prague, Czech Republic
| | - Jonas Neipel
- Max Planck Institute for the Physics of Complex Systems, 01187Dresden, Germany
| | - Caitlin E. Cornell
- Department of Bioengineering, University of California, Berkeley, CA94720
| | - Ronald Naumann
- Max Planck Institute of Molecular Cell Biology and Genetics, 01307Dresden, Germany
| | - Lokesh G. Pimpale
- Max Planck Institute of Molecular Cell Biology and Genetics, 01307Dresden, Germany
| | - Frank Jülicher
- Max Planck Institute for the Physics of Complex Systems, 01187Dresden, Germany
- Cluster of Excellence Physics of Life, Technical University Dresden, 01062Dresden, Germany
| | - Stephan W. Grill
- Max Planck Institute of Molecular Cell Biology and Genetics, 01307Dresden, Germany
- Cluster of Excellence Physics of Life, Technical University Dresden, 01062Dresden, Germany
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2
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Stolpner NJ, Manzi NI, Su T, Dickinson DJ. Apical PAR protein caps orient the mitotic spindle in C. elegans early embryos. Curr Biol 2023; 33:4312-4329.e6. [PMID: 37729910 PMCID: PMC10615879 DOI: 10.1016/j.cub.2023.08.069] [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: 03/27/2023] [Revised: 07/24/2023] [Accepted: 08/23/2023] [Indexed: 09/22/2023]
Abstract
During embryonic development, oriented cell divisions are important for patterned tissue growth and cell fate specification. Cell division orientation is controlled in part by asymmetrically localized polarity proteins, which establish functional domains of the cell membrane and interact with microtubule regulators to position the mitotic spindle. For example, in the 8-cell mouse embryo, apical polarity proteins form caps on the outside, contact-free surface of the embryo that position the mitotic spindle to execute asymmetric cell division. A similar radial or "inside-outside" polarity is established at an early stage in many other animal embryos, but in most cases, it remains unclear how inside-outside polarity is established and how it influences downstream cell behaviors. Here, we explore inside-outside polarity in C. elegans somatic blastomeres using spatiotemporally controlled protein degradation and live embryo imaging. We show that PAR polarity proteins, which form apical caps at the center of the contact-free membrane, localize dynamically during the cell cycle and contribute to spindle orientation and proper cell positioning. Surprisingly, isolated single blastomeres lacking cell contacts are able to break symmetry and form PAR-3/atypical protein kinase C (aPKC) caps. Polarity caps form independently of actomyosin flows and microtubules and can regulate spindle orientation in cooperation with the key polarity kinase aPKC. Together, our results reveal a role for apical polarity caps in regulating spindle orientation in symmetrically dividing cells and provide novel insights into how these structures are formed.
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Affiliation(s)
- Naomi J Stolpner
- Department of Molecular Biosciences, The University of Texas at Austin, 2415 Speedway, PAT 206, Austin, TX 78712, USA
| | - Nadia I Manzi
- Department of Molecular Biosciences, The University of Texas at Austin, 2415 Speedway, PAT 206, Austin, TX 78712, USA
| | - Thomas Su
- Department of Molecular Biosciences, The University of Texas at Austin, 2415 Speedway, PAT 206, Austin, TX 78712, USA
| | - Daniel J Dickinson
- Department of Molecular Biosciences, The University of Texas at Austin, 2415 Speedway, PAT 206, Austin, TX 78712, USA.
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3
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Stolpner NJ, Manzi NI, Su T, Dickinson DJ. Apical PAR-3 caps orient the mitotic spindle in C. elegans early embryos. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.03.27.534341. [PMID: 37034756 PMCID: PMC10081169 DOI: 10.1101/2023.03.27.534341] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
During embryonic development, oriented cell divisions are important for patterned tissue growth and cell fate specification. Cell division orientation is controlled in part by asymmetrically localized polarity proteins, which establish functional domains of the cell membrane and interact with microtubule regulators to position the mitotic spindle. For example, in the 8-cell mouse embryo, apical polarity proteins form caps on the outside, contact-free surface of the embryo that position the mitotic spindle to execute asymmetric cell division. A similar radial or "inside-outside" polarity is established at an early stage in many other animal embryos, but in most cases it remains unclear how inside-outside polarity is established and how it influences downstream cell behaviors. Here, we explore inside-outside polarity in C. elegans somatic blastomeres using spatiotemporally controlled protein degradation and live embryo imaging. We show that PAR polarity proteins, which form apical caps at the center of the contact free membrane, localize dynamically during the cell cycle and contribute to spindle orientation and proper cell positioning. Surprisingly, apical PAR-3 can form polarity caps independently of actomyosin flows and the small GTPase CDC-42, and can regulate spindle orientation in cooperation with the key polarity kinase aPKC. Together, our results reveal a role for apical polarity caps in regulating spindle orientation in symmetrically dividing cells and provide novel insights into how these structures are formed.
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Affiliation(s)
- Naomi J. Stolpner
- Department of Molecular Biosciences, The University of Texas at Austin, 2415 Speedway, PAT 206, Austin, TX 78712
| | - Nadia I. Manzi
- Department of Molecular Biosciences, The University of Texas at Austin, 2415 Speedway, PAT 206, Austin, TX 78712
| | - Thomas Su
- Department of Molecular Biosciences, The University of Texas at Austin, 2415 Speedway, PAT 206, Austin, TX 78712
| | - Daniel J. Dickinson
- Department of Molecular Biosciences, The University of Texas at Austin, 2415 Speedway, PAT 206, Austin, TX 78712
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4
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The Roles of Par3, Par6, and aPKC Polarity Proteins in Normal Neurodevelopment and in Neurodegenerative and Neuropsychiatric Disorders. J Neurosci 2022; 42:4774-4793. [PMID: 35705493 DOI: 10.1523/jneurosci.0059-22.2022] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2022] [Revised: 04/30/2022] [Accepted: 05/02/2022] [Indexed: 11/21/2022] Open
Abstract
Normal neural circuits and functions depend on proper neuronal differentiation, migration, synaptic plasticity, and maintenance. Abnormalities in these processes underlie various neurodevelopmental, neuropsychiatric, and neurodegenerative disorders. Neural development and maintenance are regulated by many proteins. Among them are Par3, Par6 (partitioning defective 3 and 6), and aPKC (atypical protein kinase C) families of evolutionarily conserved polarity proteins. These proteins perform versatile functions by forming tripartite or other combinations of protein complexes, which hereafter are collectively referred to as "Par complexes." In this review, we summarize the major findings on their biophysical and biochemical properties in cell polarization and signaling pathways. We next summarize their expression and localization in the nervous system as well as their versatile functions in various aspects of neurodevelopment, including neuroepithelial polarity, neurogenesis, neuronal migration, neurite differentiation, synaptic plasticity, and memory. These versatile functions rely on the fundamental roles of Par complexes in cell polarity in distinct cellular contexts. We also discuss how cell polarization may correlate with subcellular polarization in neurons. Finally, we review the involvement of Par complexes in neuropsychiatric and neurodegenerative disorders, such as schizophrenia and Alzheimer's disease. While emerging evidence indicates that Par complexes are essential for proper neural development and maintenance, many questions on their in vivo functions have yet to be answered. Thus, Par3, Par6, and aPKC continue to be important research topics to advance neuroscience.
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5
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Chapa-Y-Lazo B, Hamanaka M, Wray A, Balasubramanian MK, Mishima M. Polar relaxation by dynein-mediated removal of cortical myosin II. J Cell Biol 2021; 219:151836. [PMID: 32497213 PMCID: PMC7401816 DOI: 10.1083/jcb.201903080] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2019] [Revised: 02/03/2020] [Accepted: 05/04/2020] [Indexed: 12/24/2022] Open
Abstract
Nearly six decades ago, Lewis Wolpert proposed the relaxation of the polar cell cortex by the radial arrays of astral microtubules as a mechanism for cleavage furrow induction. While this mechanism has remained controversial, recent work has provided evidence for polar relaxation by astral microtubules, although its molecular mechanisms remain elusive. Here, using C. elegans embryos, we show that polar relaxation is achieved through dynein-mediated removal of myosin II from the polar cortexes. Mutants that position centrosomes closer to the polar cortex accelerated furrow induction, whereas suppression of dynein activity delayed furrowing. We show that dynein-mediated removal of myosin II from the polar cortexes triggers a bidirectional cortical flow toward the cell equator, which induces the assembly of the actomyosin contractile ring. These results provide a molecular mechanism for the aster-dependent polar relaxation, which works in parallel with equatorial stimulation to promote robust cytokinesis.
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Affiliation(s)
- Bernardo Chapa-Y-Lazo
- Centre for Mechanochemical Cell Biology & Division of Biomedical Sciences, Warwick Medical School, Coventry, UK
| | - Motonari Hamanaka
- Centre for Mechanochemical Cell Biology & Division of Biomedical Sciences, Warwick Medical School, Coventry, UK.,Hokkaido University, Sapporo, Japan
| | - Alexander Wray
- Centre for Mechanochemical Cell Biology & Division of Biomedical Sciences, Warwick Medical School, Coventry, UK.,University of Nottingham, Nottingham, UK
| | - Mohan K Balasubramanian
- Centre for Mechanochemical Cell Biology & Division of Biomedical Sciences, Warwick Medical School, Coventry, UK
| | - Masanori Mishima
- Centre for Mechanochemical Cell Biology & Division of Biomedical Sciences, Warwick Medical School, Coventry, UK
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6
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Delattre M, Goehring NW. The first steps in the life of a worm: Themes and variations in asymmetric division in C. elegans and other nematodes. Curr Top Dev Biol 2021; 144:269-308. [PMID: 33992156 DOI: 10.1016/bs.ctdb.2020.12.006] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Starting with Boveri in the 1870s, microscopic investigation of early embryogenesis in a broad swath of nematode species revealed the central role of asymmetric cell division in embryonic axis specification, blastomere positioning, and cell fate specification. Notably, across the class Chromadorea, a conserved theme emerges-asymmetry is first established in the zygote and specifies its asymmetric division, giving rise to an anterior somatic daughter cell and a posterior germline daughter cell. Beginning in the 1980s, the emergence of Caenorhabditis elegans as a model organism saw the advent of genetic tools that enabled rapid progress in our understanding of the molecular mechanisms underlying asymmetric division, in many cases defining key paradigms that turn out to regulate asymmetric division in a wide range of systems. Yet, the consequence of this focus on C. elegans came at the expense of exploring the extant diversity of developmental variation exhibited across nematode species. Given the resurgent interest in evolutionary studies facilitated in part by new tools, here we revisit the diversity in this asymmetric first division, juxtaposing molecular insight into mechanisms of symmetry-breaking, spindle positioning and fate specification, with a consideration of plasticity and variability within and between species. In the process, we hope to highlight questions of evolutionary forces and molecular variation that may have shaped the extant diversity of developmental mechanisms observed across Nematoda.
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Affiliation(s)
- Marie Delattre
- Laboratory of Biology and Modeling of the Cell, Ecole Normale Supérieure de Lyon, CNRS, Inserm, UCBL, Lyon, France.
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7
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Gubieda AG, Packer JR, Squires I, Martin J, Rodriguez J. Going with the flow: insights from Caenorhabditis elegans zygote polarization. Philos Trans R Soc Lond B Biol Sci 2020; 375:20190555. [PMID: 32829680 PMCID: PMC7482210 DOI: 10.1098/rstb.2019.0555] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/09/2020] [Indexed: 12/12/2022] Open
Abstract
Cell polarity is the asymmetric distribution of cellular components along a defined axis. Polarity relies on complex signalling networks between conserved patterning proteins, including the PAR (partitioning defective) proteins, which become segregated in response to upstream symmetry breaking cues. Although the mechanisms that drive the asymmetric localization of these proteins are dependent upon cell type and context, in many cases the regulation of actomyosin cytoskeleton dynamics is central to the transport, recruitment and/or stabilization of these polarity effectors into defined subcellular domains. The transport or advection of PAR proteins by an actomyosin flow was first observed in the Caenorhabditis elegans zygote more than a decade ago. Since then a multifaceted approach, using molecular methods, high-throughput screens, and biophysical and computational models, has revealed further aspects of this flow and how polarity regulators respond to and modulate it. Here, we review recent findings on the interplay between actomyosin flow and the PAR patterning networks in the polarization of the C. elegans zygote. We also discuss how these discoveries and developed methods are shaping our understanding of other flow-dependent polarizing systems. This article is part of a discussion meeting issue 'Contemporary morphogenesis'.
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Affiliation(s)
| | | | | | | | - Josana Rodriguez
- Biosciences Institute, Newcastle University, Newcastle upon Tyne NE2 4HH, UK
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8
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Pimpale LG, Middelkoop TC, Mietke A, Grill SW. Cell lineage-dependent chiral actomyosin flows drive cellular rearrangements in early Caenorhabditis elegans development. eLife 2020; 9:54930. [PMID: 32644039 PMCID: PMC7394549 DOI: 10.7554/elife.54930] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2020] [Accepted: 07/05/2020] [Indexed: 12/15/2022] Open
Abstract
Proper positioning of cells is essential for many aspects of development. Daughter cell positions can be specified via orienting the cell division axis during cytokinesis. Rotatory actomyosin flows during division have been implied in specifying and reorienting the cell division axis, but how general such reorientation events are, and how they are controlled, remains unclear. We followed the first nine divisions of Caenorhabditis elegans embryo development and demonstrate that chiral counter-rotating flows arise systematically in early AB lineage, but not in early P/EMS lineage cell divisions. Combining our experiments with thin film active chiral fluid theory we identify a mechanism by which chiral counter-rotating actomyosin flows arise in the AB lineage only, and show that they drive lineage-specific spindle skew and cell reorientation events. In conclusion, our work sheds light on the physical processes that underlie chiral morphogenesis in early development.
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Affiliation(s)
- Lokesh G Pimpale
- Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, Germany.,Biotechnology Center, TU Dresden, Dresden, Germany.,Cluster of Excellence Physics of Life, TU Dresden, Dresden, Germany
| | - Teije C Middelkoop
- Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, Germany.,Biotechnology Center, TU Dresden, Dresden, Germany.,Cluster of Excellence Physics of Life, TU Dresden, Dresden, Germany
| | - Alexander Mietke
- Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, Germany.,Max Planck Institute for the Physics of Complex Systems, Dresden, Germany.,Chair of Scientific Computing for Systems Biology, Faculty of Computer Science, TU Dresden, Dresden, Germany.,Center for Systems Biology Dresden, Dresden, Germany.,Department of Mathematics, Massachusetts Institute of Technology, Cambridge, United States
| | - Stephan W Grill
- Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, Germany.,Biotechnology Center, TU Dresden, Dresden, Germany.,Cluster of Excellence Physics of Life, TU Dresden, Dresden, Germany
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9
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Cobbaut M, Karagil S, Bruno L, Diaz de la Loza MDC, Mackenzie FE, Stolinski M, Elbediwy A. Dysfunctional Mechanotransduction through the YAP/TAZ/Hippo Pathway as a Feature of Chronic Disease. Cells 2020; 9:cells9010151. [PMID: 31936297 PMCID: PMC7016982 DOI: 10.3390/cells9010151] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2019] [Revised: 01/02/2020] [Accepted: 01/04/2020] [Indexed: 02/07/2023] Open
Abstract
In order to ascertain their external environment, cells and tissues have the capability to sense and process a variety of stresses, including stretching and compression forces. These mechanical forces, as experienced by cells and tissues, are then converted into biochemical signals within the cell, leading to a number of cellular mechanisms being activated, including proliferation, differentiation and migration. If the conversion of mechanical cues into biochemical signals is perturbed in any way, then this can be potentially implicated in chronic disease development and processes such as neurological disorders, cancer and obesity. This review will focus on how the interplay between mechanotransduction, cellular structure, metabolism and signalling cascades led by the Hippo-YAP/TAZ axis can lead to a number of chronic diseases and suggest how we can target various pathways in order to design therapeutic targets for these debilitating diseases and conditions.
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Affiliation(s)
- Mathias Cobbaut
- Protein Phosphorylation Lab, Francis Crick Institute, London NW1 1AT, UK;
| | - Simge Karagil
- Department of Biomolecular Sciences, Kingston University, Kingston-upon-Thames KT1 2EE, UK; (S.K.); (L.B.); (M.S.)
| | - Lucrezia Bruno
- Department of Biomolecular Sciences, Kingston University, Kingston-upon-Thames KT1 2EE, UK; (S.K.); (L.B.); (M.S.)
- Department of Chemical and Pharmaceutical Sciences, Kingston University, Kingston-upon-Thames KT1 2EE, UK;
| | | | - Francesca E Mackenzie
- Department of Chemical and Pharmaceutical Sciences, Kingston University, Kingston-upon-Thames KT1 2EE, UK;
| | - Michael Stolinski
- Department of Biomolecular Sciences, Kingston University, Kingston-upon-Thames KT1 2EE, UK; (S.K.); (L.B.); (M.S.)
| | - Ahmed Elbediwy
- Department of Biomolecular Sciences, Kingston University, Kingston-upon-Thames KT1 2EE, UK; (S.K.); (L.B.); (M.S.)
- Correspondence:
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10
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Wang T, Ma G, Ang CS, Korhonen PK, Stroehlein AJ, Young ND, Hofmann A, Chang BCH, Williamson NA, Gasser RB. The developmental phosphoproteome of Haemonchus contortus. J Proteomics 2019; 213:103615. [PMID: 31846766 DOI: 10.1016/j.jprot.2019.103615] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2019] [Revised: 11/22/2019] [Accepted: 12/13/2019] [Indexed: 12/22/2022]
Abstract
Protein phosphorylation plays essential roles in many cellular processes. Despite recent progress in the genomics, transcriptomics and proteomics of socioeconomically important parasitic nematodes, there is scant phosphoproteomic data to underpin molecular biological discovery. Here, using the phosphopeptide enrichment-based LC-MS/MS and data-independent acquisition (DIA) quantitation, we characterised the first developmental phosphoproteome of the parasitic nematode Haemonchus contortus - one of the most pathogenic parasites of ruminant livestock. Totally, 1804 phosphorylated proteins with 4406 phosphorylation sites ('phosphosites') from different developmental stages/sexes were identified. Bioinformatic analyses of quantified 'phosphosites' exhibited distinctive stage- and sex-specific patterns during development, and identified a subset of phosphoproteins proposed to play crucial roles in processes such as spindle positioning, signal transduction and kinase activity. A sequence-based comparison of the phosphoproteome of H. contortus with those of two free-living nematode species (Caenorhabditis elegans and Pristionchus pacificus) suggested a limited number of common protein phosphorylation events among these species. Our findings infer active roles for protein phosphorylation in the adaptation of a parasitic nematode to a constantly changing external environment. The phosphoproteomic data set for H. contortus provides a basis to better understand phosphorylation and associated biological processes (e.g., regulation of signal transduction), and might enable the discovery of novel anthelmintic targets. SIGNIFICANCE: Here, we report the first phosphoproteome for a socioeconomically parasitic nematode (Haemonchus contortus). This phosphoproteome exhibits distinctive patterns during development, suggesting active roles of post-translational modification in the parasite's adaptation to changing environments within and outside of the host animal. This work sheds a light on the developmental phosphorylation in a parasitic nematode, and could enable the discovery of novel interventions against major pathogens.
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Affiliation(s)
- Tao Wang
- Department of Veterinary Biosciences, Melbourne Veterinary School, The University of Melbourne, Parkville, Victoria 3010, Australia.
| | - Guangxu Ma
- Department of Veterinary Biosciences, Melbourne Veterinary School, The University of Melbourne, Parkville, Victoria 3010, Australia.
| | - Ching-Seng Ang
- Bio21 Mass Spectrometry and Proteomics Facility, The University of Melbourne, Parkville, Victoria 3010, Australia.
| | - Pasi K Korhonen
- Department of Veterinary Biosciences, Melbourne Veterinary School, The University of Melbourne, Parkville, Victoria 3010, Australia.
| | - Andreas J Stroehlein
- Department of Veterinary Biosciences, Melbourne Veterinary School, The University of Melbourne, Parkville, Victoria 3010, Australia.
| | - Neil D Young
- Department of Veterinary Biosciences, Melbourne Veterinary School, The University of Melbourne, Parkville, Victoria 3010, Australia.
| | - Andreas Hofmann
- Department of Veterinary Biosciences, Melbourne Veterinary School, The University of Melbourne, Parkville, Victoria 3010, Australia.
| | - Bill C H Chang
- Department of Veterinary Biosciences, Melbourne Veterinary School, The University of Melbourne, Parkville, Victoria 3010, Australia.
| | - Nicholas A Williamson
- Bio21 Mass Spectrometry and Proteomics Facility, The University of Melbourne, Parkville, Victoria 3010, Australia.
| | - Robin B Gasser
- Department of Veterinary Biosciences, Melbourne Veterinary School, The University of Melbourne, Parkville, Victoria 3010, Australia.
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11
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Kotak S. Mechanisms of Spindle Positioning: Lessons from Worms and Mammalian Cells. Biomolecules 2019; 9:E80. [PMID: 30823600 PMCID: PMC6406873 DOI: 10.3390/biom9020080] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2019] [Revised: 02/13/2019] [Accepted: 02/18/2019] [Indexed: 02/06/2023] Open
Abstract
Proper positioning of the mitotic spindle is fundamental for specifying the site for cleavage furrow, and thus regulates the appropriate sizes and accurate distribution of the cell fate determinants in the resulting daughter cells during development and in the stem cells. The past couple of years have witnessed tremendous work accomplished in the area of spindle positioning, and this has led to the emergence of a working model unravelling in-depth mechanistic insight of the underlying process orchestrating spindle positioning. It is evident now that the correct positioning of the mitotic spindle is not only guided by the chemical cues (protein⁻protein interactions) but also influenced by the physical nature of the cellular environment. In metazoans, the key players that regulate proper spindle positioning are the actin-rich cell cortex and associated proteins, the ternary complex (Gα/GPR-1/2/LIN-5 in Caenorhabditis elegans, Gαi/Pins/Mud in Drosophila and Gαi1-3/LGN/NuMA in humans), minus-end-directed motor protein dynein and the cortical machinery containing myosin. In this review, I will mainly discuss how the abovementioned components precisely and spatiotemporally regulate spindle positioning by sensing the physicochemical environment for execution of flawless mitosis.
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Affiliation(s)
- Sachin Kotak
- Department of Microbiology and Cell Biology (MCB), Indian Institute of Science (IISc), Bangalore 560012, India.
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12
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Roman AC, Garrido-Jimenez S, Diaz-Chamorro S, Centeno F, Carvajal-Gonzalez JM. Centriole Positioning: Not Just a Little Dot in the Cell. Results Probl Cell Differ 2019; 67:201-221. [PMID: 31435796 DOI: 10.1007/978-3-030-23173-6_8] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
Organelle positioning as many other morphological parameters in a cell is not random. Centriole positioning as centrosomes or ciliary basal bodies is not an exception to this rule in cell biology. Indeed, centriole positioning is a tightly regulated process that occurs during development, and it is critical for many organs to function properly, not just during development but also in the adulthood. In this book chapter, we overview our knowledge on centriole positioning in different and highly specialized animal cells like photoreceptor or ependymal cells. We will also discuss recent advances in the discovery of molecular pathways involved in this process, mostly related to the cytoskeleton and the cell polarity pathways. And finally, we present quantitative methods that have been used to assess centriole positioning in different cell types although mostly in epithelial cells.
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Affiliation(s)
- Angel-Carlos Roman
- Facultad de Ciencias, Departamento de Bioquímica, Biología Molecular y Genética, Universidad de Extremadura, Badajoz, Spain
| | - Sergio Garrido-Jimenez
- Facultad de Ciencias, Departamento de Bioquímica, Biología Molecular y Genética, Universidad de Extremadura, Badajoz, Spain
| | - Selene Diaz-Chamorro
- Facultad de Ciencias, Departamento de Bioquímica, Biología Molecular y Genética, Universidad de Extremadura, Badajoz, Spain
| | - Francisco Centeno
- Facultad de Ciencias, Departamento de Bioquímica, Biología Molecular y Genética, Universidad de Extremadura, Badajoz, Spain
| | - Jose Maria Carvajal-Gonzalez
- Facultad de Ciencias, Departamento de Bioquímica, Biología Molecular y Genética, Universidad de Extremadura, Badajoz, Spain.
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13
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Pires HR, Boxem M. Mapping the Polarity Interactome. J Mol Biol 2018; 430:3521-3544. [DOI: 10.1016/j.jmb.2017.12.017] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2017] [Revised: 12/14/2017] [Accepted: 12/18/2017] [Indexed: 12/11/2022]
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14
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Ren M, Zhao L, Ding X, Krasteva N, Rui Q, Wang D. Developmental basis for intestinal barrier against the toxicity of graphene oxide. Part Fibre Toxicol 2018; 15:26. [PMID: 29929559 PMCID: PMC6013870 DOI: 10.1186/s12989-018-0262-4] [Citation(s) in RCA: 56] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2017] [Accepted: 05/21/2018] [Indexed: 01/23/2023] Open
Abstract
BACKGROUND Intestinal barrier is crucial for animals against translocation of engineered nanomaterials (ENMs) into secondary targeted organs. However, the molecular mechanisms for the role of intestinal barrier against ENMs toxicity are still largely unclear. The intestine of Caenorhabditis elegans is a powerful in vivo experimental system for the study on intestinal function. In this study, we investigated the molecular basis for intestinal barrier against toxicity and translocation of graphene oxide (GO) using C. elegans as a model animal. RESULTS Based on the genetic screen of genes required for the control of intestinal development at different aspects using intestine-specific RNA interference (RNAi) technique, we identified four genes (erm-1, pkc-3, hmp-2 and act-5) required for the function of intestinal barrier against GO toxicity. Under normal conditions, mutation of any of these genes altered the intestinal permeability. With the focus on PKC-3, an atypical protein kinase C, we identified an intestinal signaling cascade of PKC-3-SEC-8-WTS-1, which implies that PKC-3 might regulate intestinal permeability and GO toxicity by affecting the function of SEC-8-mediated exocyst complex and the role of WTS-1 in maintaining integrity of apical intestinal membrane. ISP-1 and SOD-3, two proteins required for the control of oxidative stress, were also identified as downstream targets for PKC-3, and functioned in parallel with WTS-1 in the regulation of GO toxicity. CONCLUSIONS Using C. elegans as an in vivo assay system, we found that several developmental genes required for the control of intestinal development regulated both the intestinal permeability and the GO toxicity. With the focus on PKC-3, we raised two intestinal signaling cascades, PKC-3-SEC-8-WTS-1 and PKC-3-ISP-1/SOD-3. Our results will strengthen our understanding the molecular basis for developmental machinery of intestinal barrier against GO toxicity and translocation in animals.
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Affiliation(s)
- Mingxia Ren
- Key Laboratory of Environmental Medicine Engineering in Ministry of Education, Medical School, Southeast University, Nanjing, 210009 China
| | - Li Zhao
- Key Laboratory of Environmental Medicine Engineering in Ministry of Education, Medical School, Southeast University, Nanjing, 210009 China
| | - Xuecheng Ding
- College of Life Sciences, Nanjing Agricultural University, Nanjing, 210095 China
| | - Natalia Krasteva
- Institute of Biophysics and Biomedical Engineering, Bulgarian Academy of Science, 1113 Sofia, Bulgaria
| | - Qi Rui
- College of Life Sciences, Nanjing Agricultural University, Nanjing, 210095 China
| | - Dayong Wang
- Key Laboratory of Environmental Medicine Engineering in Ministry of Education, Medical School, Southeast University, Nanjing, 210009 China
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15
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Heppert JK, Pani AM, Roberts AM, Dickinson DJ, Goldstein B. A CRISPR Tagging-Based Screen Reveals Localized Players in Wnt-Directed Asymmetric Cell Division. Genetics 2018; 208:1147-1164. [PMID: 29348144 PMCID: PMC5844328 DOI: 10.1534/genetics.117.300487] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2017] [Accepted: 01/08/2018] [Indexed: 11/18/2022] Open
Abstract
Oriented cell divisions are critical to establish and maintain cell fates and tissue organization. Diverse extracellular and intracellular cues have been shown to provide spatial information for mitotic spindle positioning; however, the molecular mechanisms by which extracellular signals communicate with cells to direct mitotic spindle positioning are largely unknown. In animal cells, oriented cell divisions are often achieved by the localization of force-generating motor protein complexes to discrete cortical domains. Disrupting either these force-generating complexes or proteins that globally affect microtubule stability results in defects in mitotic positioning, irrespective of whether these proteins function as spatial cues for spindle orientation. This poses a challenge to traditional genetic dissection of this process. Therefore, as an alternative strategy to identify key proteins that act downstream of intercellular signaling, we screened the localization of many candidate proteins by inserting fluorescent tags directly into endogenous gene loci, without overexpressing the proteins. We tagged 23 candidate proteins in Caenorhabditis elegans and examined each protein's localization in a well-characterized, oriented cell division in the four-cell-stage embryo. We used cell manipulations and genetic experiments to determine which cells harbor key localized proteins and which signals direct these localizations in vivo We found that Dishevelled and adenomatous polyposis coli homologs are polarized during this oriented cell division in response to a Wnt signal, but two proteins typically associated with mitotic spindle positioning, homologs of NuMA and Dynein, were not detectably polarized. These results suggest an unexpected mechanism for mitotic spindle positioning in this system, they pinpoint key proteins of interest, and they highlight the utility of a screening approach based on analyzing the localization of endogenously tagged proteins.
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Affiliation(s)
- Jennifer K Heppert
- Department of Biology, University of North Carolina at Chapel Hill, North Carolina 27599
| | - Ariel M Pani
- Department of Biology, University of North Carolina at Chapel Hill, North Carolina 27599
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, North Carolina 27599
| | - Allyson M Roberts
- Curriculum in Genetics and Molecular Biology, University of North Carolina at Chapel Hill, North Carolina 27599
| | - Daniel J Dickinson
- Department of Biology, University of North Carolina at Chapel Hill, North Carolina 27599
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, North Carolina 27599
| | - Bob Goldstein
- Department of Biology, University of North Carolina at Chapel Hill, North Carolina 27599
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, North Carolina 27599
- Curriculum in Genetics and Molecular Biology, University of North Carolina at Chapel Hill, North Carolina 27599
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16
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Sugioka K, Fielmich LE, Mizumoto K, Bowerman B, van den Heuvel S, Kimura A, Sawa H. Tumor suppressor APC is an attenuator of spindle-pulling forces during C. elegans asymmetric cell division. Proc Natl Acad Sci U S A 2018; 115:E954-E963. [PMID: 29348204 PMCID: PMC5798331 DOI: 10.1073/pnas.1712052115] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The adenomatous polyposis coli (APC) tumor suppressor has dual functions in Wnt/β-catenin signaling and accurate chromosome segregation and is frequently mutated in colorectal cancers. Although APC contributes to proper cell division, the underlying mechanisms remain poorly understood. Here we show that Caenorhabditis elegans APR-1/APC is an attenuator of the pulling forces acting on the mitotic spindle. During asymmetric cell division of the C. elegans zygote, a LIN-5/NuMA protein complex localizes dynein to the cell cortex to generate pulling forces on astral microtubules that position the mitotic spindle. We found that APR-1 localizes to the anterior cell cortex in a Par-aPKC polarity-dependent manner and suppresses anterior centrosome movements. Our combined cell biological and mathematical analyses support the conclusion that cortical APR-1 reduces force generation by stabilizing microtubule plus-ends at the cell cortex. Furthermore, APR-1 functions in coordination with LIN-5 phosphorylation to attenuate spindle-pulling forces. Our results document a physical basis for the attenuation of spindle-pulling force, which may be generally used in asymmetric cell division and, when disrupted, potentially contributes to division defects in cancer.
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Affiliation(s)
- Kenji Sugioka
- Multicellular Organization Laboratory, National Institute of Genetics, 411-8540 Mishima, Japan
- RIKEN Center for Developmental Biology, Chuo-ku, 650-0047 Kobe, Japan
- Institute of Molecular Biology, University of Oregon, Eugene, OR 97403
| | - Lars-Eric Fielmich
- Developmental Biology, Biology Department, Science 4 Life, Utrecht University, 3584 CH Utrecht, The Netherlands
| | - Kota Mizumoto
- RIKEN Center for Developmental Biology, Chuo-ku, 650-0047 Kobe, Japan
| | - Bruce Bowerman
- Institute of Molecular Biology, University of Oregon, Eugene, OR 97403
| | - Sander van den Heuvel
- Developmental Biology, Biology Department, Science 4 Life, Utrecht University, 3584 CH Utrecht, The Netherlands;
| | - Akatsuki Kimura
- Cell Architecture Laboratory, National Institute of Genetics, 411-8540 Mishima, Japan;
- Department of Genetics, School of Life Science, Sokendai, 411-8540 Mishima, Japan
| | - Hitoshi Sawa
- Multicellular Organization Laboratory, National Institute of Genetics, 411-8540 Mishima, Japan;
- RIKEN Center for Developmental Biology, Chuo-ku, 650-0047 Kobe, Japan
- Department of Genetics, School of Life Science, Sokendai, 411-8540 Mishima, Japan
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17
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Costache V, Hebras C, Pruliere G, Besnardeau L, Failla M, Copley RR, Burgess D, Chenevert J, McDougall A. Kif2 localizes to a subdomain of cortical endoplasmic reticulum that drives asymmetric spindle position. Nat Commun 2017; 8:917. [PMID: 29030551 PMCID: PMC5640700 DOI: 10.1038/s41467-017-01048-8] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2016] [Accepted: 08/16/2017] [Indexed: 12/22/2022] Open
Abstract
Asymmetric positioning of the mitotic spindle is a fundamental process responsible for creating sibling cell size asymmetry; however, how the cortex causes the depolymerization of astral microtubules during asymmetric spindle positioning has remained elusive. Early ascidian embryos possess a large cortical subdomain of endoplasmic reticulum (ER) that causes asymmetric spindle positioning driving unequal cell division. Here we show that the microtubule depolymerase Kif2 localizes to this subdomain of cortical ER. Rapid live-cell imaging reveals that microtubules are less abundant in the subdomain of cortical ER. Inhibition of Kif2 function prevents the development of mitotic aster asymmetry and spindle pole movement towards the subdomain of cortical ER, whereas locally increasing microtubule depolymerization causes exaggerated asymmetric spindle positioning. This study shows that the microtubule depolymerase Kif2 is localized to a cortical subdomain of endoplasmic reticulum that is involved in asymmetric spindle positioning during unequal cell division. Early ascidian embryos have a cortical subdomain of endoplasmic reticulum (ER) that controls asymmetric spindle positioning driving unequal cell division. Here the authors show that the microtubule depolymerase Kif2 is localized to a cortical subdomain of the ER that is involved in asymmetric spindle positioning.
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Affiliation(s)
- Vlad Costache
- Sorbonne Universités, UPMC Univ Paris 06, CNRS, Laboratoire de Biologie du Développement de Villefranche-sur-mer (LBDV), Observatoire Océanologique, Villefranche sur-mer, 06230, France
| | - Celine Hebras
- Sorbonne Universités, UPMC Univ Paris 06, CNRS, Laboratoire de Biologie du Développement de Villefranche-sur-mer (LBDV), Observatoire Océanologique, Villefranche sur-mer, 06230, France
| | - Gerard Pruliere
- Sorbonne Universités, UPMC Univ Paris 06, CNRS, Laboratoire de Biologie du Développement de Villefranche-sur-mer (LBDV), Observatoire Océanologique, Villefranche sur-mer, 06230, France
| | - Lydia Besnardeau
- Sorbonne Universités, UPMC Univ Paris 06, CNRS, Laboratoire de Biologie du Développement de Villefranche-sur-mer (LBDV), Observatoire Océanologique, Villefranche sur-mer, 06230, France
| | - Margaux Failla
- Sorbonne Universités, UPMC Univ Paris 06, CNRS, Laboratoire de Biologie du Développement de Villefranche-sur-mer (LBDV), Observatoire Océanologique, Villefranche sur-mer, 06230, France
| | - Richard R Copley
- Sorbonne Universités, UPMC Univ Paris 06, CNRS, Laboratoire de Biologie du Développement de Villefranche-sur-mer (LBDV), Observatoire Océanologique, Villefranche sur-mer, 06230, France
| | - David Burgess
- Boston College, Biology Department, 528 Higgins Hall, 140 Commonwealth Ave, Chestnut Hill, MA, 0246, USA
| | - Janet Chenevert
- Sorbonne Universités, UPMC Univ Paris 06, CNRS, Laboratoire de Biologie du Développement de Villefranche-sur-mer (LBDV), Observatoire Océanologique, Villefranche sur-mer, 06230, France.
| | - Alex McDougall
- Sorbonne Universités, UPMC Univ Paris 06, CNRS, Laboratoire de Biologie du Développement de Villefranche-sur-mer (LBDV), Observatoire Océanologique, Villefranche sur-mer, 06230, France.
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18
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Schmidt R, Fielmich LE, Grigoriev I, Katrukha EA, Akhmanova A, van den Heuvel S. Two populations of cytoplasmic dynein contribute to spindle positioning in C. elegans embryos. J Cell Biol 2017; 216:2777-2793. [PMID: 28739679 PMCID: PMC5584144 DOI: 10.1083/jcb.201607038] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2016] [Revised: 05/08/2017] [Accepted: 06/28/2017] [Indexed: 12/14/2022] Open
Abstract
The position of the mitotic spindle is tightly controlled in animal cells as it determines the plane and orientation of cell division. Contacts between cytoplasmic dynein and astral microtubules (MTs) at the cell cortex generate pulling forces that position the spindle. An evolutionarily conserved Gα-GPR-1/2Pins/LGN-LIN-5Mud/NuMA cortical complex interacts with dynein and is required for pulling force generation, but the dynamics of this process remain unclear. In this study, by fluorescently labeling endogenous proteins in Caenorhabditis elegans embryos, we show that dynein exists in two distinct cortical populations. One population directly depends on LIN-5, whereas the other is concentrated at MT plus ends and depends on end-binding (EB) proteins. Knockout mutants lacking all EBs are viable and fertile and display normal pulling forces and spindle positioning. However, EB protein-dependent dynein plus end tracking was found to contribute to force generation in embryos with a partially perturbed dynein function, indicating the existence of two mechanisms that together create a highly robust force-generating system.
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Affiliation(s)
- Ruben Schmidt
- Developmental Biology, Department of Biology, Faculty of Sciences, Utrecht University, Utrecht, Netherlands
- Cell Biology, Department of Biology, Faculty of Sciences, Utrecht University, Utrecht, Netherlands
| | - Lars-Eric Fielmich
- Developmental Biology, Department of Biology, Faculty of Sciences, Utrecht University, Utrecht, Netherlands
| | - Ilya Grigoriev
- Cell Biology, Department of Biology, Faculty of Sciences, Utrecht University, Utrecht, Netherlands
| | - Eugene A Katrukha
- Cell Biology, Department of Biology, Faculty of Sciences, Utrecht University, Utrecht, Netherlands
| | - Anna Akhmanova
- Cell Biology, Department of Biology, Faculty of Sciences, Utrecht University, Utrecht, Netherlands
| | - Sander van den Heuvel
- Developmental Biology, Department of Biology, Faculty of Sciences, Utrecht University, Utrecht, Netherlands
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19
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Fickentscher R, Weiss M. Physical determinants of asymmetric cell divisions in the early development of Caenorhabditis elegans. Sci Rep 2017; 7:9369. [PMID: 28839200 PMCID: PMC5571195 DOI: 10.1038/s41598-017-09690-4] [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: 03/10/2017] [Accepted: 07/25/2017] [Indexed: 01/06/2023] Open
Abstract
Asymmetric cell divisions are of fundamental importance for the development of multicellular organisms, e.g. for the generation of founder cells. Prime examples are asymmetric cell divisions in germline precursors during the early embryogenesis of the transparent roundworm Caenorhabditis elegans, one of the major developmental model organisms. However, due to a lack of quantitative data it has remained unclear how frequent unequal daughter cell sizes emerge in the worm’s early embryogenesis, and whether these originate from sterical or biochemical cues. Using quantitative light-sheet microscopy, we have found that about 40% of all cell divisions in C. elegans until gastrulation generate daughter cells with significantly different volumes. Removing the embryo’s rigid eggshell revealed asymmetric divisions in somatic cells to be primarily induced by steric effects. Division asymmetries in the germline remained unaltered and were correctly reproduced by a model based on a cell-size independent, eccentric displacement of the metaphase plate. Our data suggest that asymmetric cell divisions, imposed by physical determinants, are essential for establishing important cell-cell interactions that eventually fuel a successful embryogenesis.
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Affiliation(s)
- Rolf Fickentscher
- Experimental Physics I, University of Bayreuth, D-95440, Bayreuth, Germany
| | - Matthias Weiss
- Experimental Physics I, University of Bayreuth, D-95440, Bayreuth, Germany.
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20
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Mazel T. Crosstalk of cell polarity signaling pathways. PROTOPLASMA 2017; 254:1241-1258. [PMID: 28293820 DOI: 10.1007/s00709-017-1075-2] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2016] [Accepted: 01/02/2017] [Indexed: 06/06/2023]
Abstract
Cell polarity, the asymmetric organization of cellular components along one or multiple axes, is present in most cells. From budding yeast cell polarization induced by pheromone signaling, oocyte polarization at fertilization to polarized epithelia and neuronal cells in multicellular organisms, similar mechanisms are used to determine cell polarity. Crucial role in this process is played by signaling lipid molecules, small Rho family GTPases and Par proteins. All these signaling circuits finally govern the cytoskeleton, which is responsible for oriented cell migration, cell shape changes, and polarized membrane and organelle trafficking. Thus, typically in the process of cell polarization, most cellular constituents become polarized, including plasma membrane lipid composition, ion concentrations, membrane receptors, and proteins in general, mRNA, vesicle trafficking, or intracellular organelles. This review gives a brief overview how these systems talk to each other both during initial symmetry breaking and within the signaling feedback loop mechanisms used to preserve the polarized state.
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Affiliation(s)
- Tomáš Mazel
- Institute of Biology and Medical Genetics, First Faculty of Medicine, Charles University and General University Hospital in Prague, Albertov 4, 128 00, Prague 2, Czech Republic.
- State Institute for Drug Control, Šrobárova 48, 100 41, Prague 10, Czech Republic.
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21
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Bergstralh DT, Dawney NS, St Johnston D. Spindle orientation: a question of complex positioning. Development 2017; 144:1137-1145. [DOI: 10.1242/dev.140764] [Citation(s) in RCA: 68] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The direction in which a cell divides is determined by the orientation of its mitotic spindle at metaphase. Spindle orientation is therefore important for a wide range of developmental processes, ranging from germline stem cell division to epithelial tissue homeostasis and regeneration. In multiple cell types in multiple animals, spindle orientation is controlled by a conserved biological machine that mediates a pulling force on astral microtubules. Restricting the localization of this machine to only specific regions of the cortex can thus determine how the mitotic spindle is oriented. As we review here, recent findings based on studies in tunicate, worm, fly and vertebrate cells have revealed that the mechanisms for mediating this restriction are surprisingly diverse.
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Affiliation(s)
- Dan T. Bergstralh
- Department of Biology, University of Rochester, Rochester, NY 14627, USA
| | - Nicole S. Dawney
- Department of Biology, University of Rochester, Rochester, NY 14627, USA
| | - Daniel St Johnston
- The Gurdon Institute and the Department of Genetics, University of Cambridge, Tennis Court Road, Cambridge CB2 1QN, UK
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22
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Pacquelet A. Asymmetric Cell Division in the One-Cell C. elegans Embryo: Multiple Steps to Generate Cell Size Asymmetry. Results Probl Cell Differ 2017; 61:115-140. [PMID: 28409302 DOI: 10.1007/978-3-319-53150-2_5] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The first division of the one-cell C. elegans embryo has been a fundamental model in deciphering the mechanisms underlying asymmetric cell division. Polarization of the one-cell zygote is induced by a signal from the sperm centrosome and results in the asymmetric distribution of PAR proteins. Multiple mechanisms then maintain PAR polarity until the end of the first division. Once asymmetrically localized, PAR proteins control several essential aspects of asymmetric division, including the position of the mitotic spindle along the polarity axis. Coordination of the spindle and cytokinetic furrow positions is the next essential step to ensure proper asymmetric division. In this chapter, I review the different mechanisms underlying these successive steps of asymmetric division. Work from the last 30 years has revealed the existence of multiple and redundant regulatory pathways which ensure division robustness. Besides the essential role of PAR proteins, this work also emphasizes the importance of both microtubules and actomyosin throughout the different steps of asymmetric division.
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Affiliation(s)
- Anne Pacquelet
- CNRS, UMR6290, Rennes, France. .,Université de Rennes 1, Institut de Génétique et Développement de Rennes, Rennes, France. .,CNRS UMR6290-IGDR, 2 avenue du Professeur Léon Bernard, 35043, Rennes Cedex, France.
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23
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Wu HY, Nazockdast E, Shelley MJ, Needleman DJ. Forces positioning the mitotic spindle: Theories, and now experiments. Bioessays 2016; 39. [PMID: 28026040 DOI: 10.1002/bies.201600212] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
The position of the spindle determines the position of the cleavage plane, and is thus crucial for cell division. Although spindle positioning has been extensively studied, the underlying forces ultimately responsible for moving the spindle remain poorly understood. A recent pioneering study by Garzon-Coral et al. uses magnetic tweezers to perform the first direct measurements of the forces involved in positioning the mitotic spindle. Combining this with molecular perturbations and geometrical effects, they use their data to argue that the forces that keep the spindle in its proper position for cell division arise from astral microtubules growing and pushing against the cell's cortex. Here, we review these ground-breaking experiments, the various biomechanical models for spindle positioning that they seek to differentiate, and discuss new questions raised by these measurements.
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Affiliation(s)
- Hai-Yin Wu
- Department of Physics, Harvard University, Cambridge, MA, USA
- Faculty of Arts and Sciences Center for Systems Biology, Harvard University, Cambridge, MA, USA
| | - Ehssan Nazockdast
- Center for Computational Biology, Simons Foundation, New York, NY, USA
| | - Michael J Shelley
- Center for Computational Biology, Simons Foundation, New York, NY, USA
- Courant Institute of Mathematical Sciences, New York University, New York, NY, USA
| | - Daniel J Needleman
- Faculty of Arts and Sciences Center for Systems Biology, Harvard University, Cambridge, MA, USA
- John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, USA
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA, USA
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24
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Portegijs V, Fielmich LE, Galli M, Schmidt R, Muñoz J, van Mourik T, Akhmanova A, Heck AJR, Boxem M, van den Heuvel S. Multisite Phosphorylation of NuMA-Related LIN-5 Controls Mitotic Spindle Positioning in C. elegans. PLoS Genet 2016; 12:e1006291. [PMID: 27711157 PMCID: PMC5053539 DOI: 10.1371/journal.pgen.1006291] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2016] [Accepted: 08/10/2016] [Indexed: 11/18/2022] Open
Abstract
During cell division, the mitotic spindle segregates replicated chromosomes to opposite poles of the cell, while the position of the spindle determines the plane of cleavage. Spindle positioning and chromosome segregation depend on pulling forces on microtubules extending from the centrosomes to the cell cortex. Critical in pulling force generation is the cortical anchoring of cytoplasmic dynein by a conserved ternary complex of Gα, GPR-1/2, and LIN-5 proteins in C. elegans (Gα–LGN–NuMA in mammals). Previously, we showed that the polarity kinase PKC-3 phosphorylates LIN-5 to control spindle positioning in early C. elegans embryos. Here, we investigate whether additional LIN-5 phosphorylations regulate cortical pulling forces, making use of targeted alteration of in vivo phosphorylated residues by CRISPR/Cas9-mediated genetic engineering. Four distinct in vivo phosphorylated LIN-5 residues were found to have critical functions in spindle positioning. Two of these residues form part of a 30 amino acid binding site for GPR-1, which we identified by reverse two-hybrid screening. We provide evidence for a dual-kinase mechanism, involving GSK3 phosphorylation of S659 followed by phosphorylation of S662 by casein kinase 1. These LIN-5 phosphorylations promote LIN-5–GPR-1/2 interaction and contribute to cortical pulling forces. The other two critical residues, T168 and T181, form part of a cyclin-dependent kinase consensus site and are phosphorylated by CDK1-cyclin B in vitro. We applied a novel strategy to characterize early embryonic defects in lethal T168,T181 knockin substitution mutants, and provide evidence for sequential LIN-5 N-terminal phosphorylation and dephosphorylation in dynein recruitment. Our data support that phosphorylation of multiple LIN-5 domains by different kinases contributes to a mechanism for spatiotemporal control of spindle positioning and chromosome segregation. Protein kinases control biological processes by phosphorylating specific amino acids of substrate proteins. It remains a major challenge to identify which phosphorylation events are critical in vivo and how phosphorylation affects protein function. Recent developments in CRISPR/Cas9-based genetic engineering make it possible to substitute individual amino acids, which allows investigating the role of single and multi-site phosphorylation of substrates in vivo. Here, we focus on an intensively phosphorylated cell division protein, LIN-5NuMA. C. elegans LIN-5 participates in chromosome segregation and is essential for positioning the spindle and cell cleavage plane during asymmetric cell division. Previously, we demonstrated that the polarity kinase PKC-3 phosphorylates LIN-5 to inhibit its function. Our current analysis reveals four additional phosphorylated residues that are critical for LIN-5 function. Two of these residues contribute to the interaction of LIN-5 with its binding partner GPR-1/2, whereas the other two residues are critical in dynein motor recruitment by LIN-5. Together, our results reveal that multisite phosphorylation of LIN-5 is essential to ensure proper chromosome segregation and spindle positioning.
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Affiliation(s)
- Vincent Portegijs
- Developmental Biology, Department of Biology, Faculty of Science, Utrecht University, Utrecht, The Netherlands
| | - Lars-Eric Fielmich
- Developmental Biology, Department of Biology, Faculty of Science, Utrecht University, Utrecht, The Netherlands
| | - Matilde Galli
- Developmental Biology, Department of Biology, Faculty of Science, Utrecht University, Utrecht, The Netherlands
| | - Ruben Schmidt
- Developmental Biology, Department of Biology, Faculty of Science, Utrecht University, Utrecht, The Netherlands
- Cell Biology, Department of Biology, Faculty of Science, Utrecht University, Utrecht, The Netherlands
| | - Javier Muñoz
- Biomolecular Mass Spectrometry and Proteomics, Bijvoet Center for Biomolecular Research and Utrecht Institute for Pharmaceutical Sciences, Utrecht University, Utrecht, The Netherlands
| | - Tim van Mourik
- Developmental Biology, Department of Biology, Faculty of Science, Utrecht University, Utrecht, The Netherlands
| | - Anna Akhmanova
- Cell Biology, Department of Biology, Faculty of Science, Utrecht University, Utrecht, The Netherlands
| | - Albert J. R. Heck
- Biomolecular Mass Spectrometry and Proteomics, Bijvoet Center for Biomolecular Research and Utrecht Institute for Pharmaceutical Sciences, Utrecht University, Utrecht, The Netherlands
| | - Mike Boxem
- Developmental Biology, Department of Biology, Faculty of Science, Utrecht University, Utrecht, The Netherlands
| | - Sander van den Heuvel
- Developmental Biology, Department of Biology, Faculty of Science, Utrecht University, Utrecht, The Netherlands
- * E-mail:
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25
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Kotak S, Afshar K, Busso C, Gönczy P. Aurora A kinase regulates proper spindle positioning in C. elegans and in human cells. J Cell Sci 2016; 129:3015-25. [PMID: 27335426 DOI: 10.1242/jcs.184416] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2015] [Accepted: 06/16/2016] [Indexed: 01/04/2023] Open
Abstract
Accurate spindle positioning is essential for error-free cell division. The one-cell Caenorhabditis elegans embryo has proven instrumental for dissecting mechanisms governing spindle positioning. Despite important progress, how the cortical forces that act on astral microtubules to properly position the spindle are modulated is incompletely understood. Here, we report that the PP6 phosphatase PPH-6 and its associated subunit SAPS-1, which positively regulate pulling forces acting on spindle poles, associate with the Aurora A kinase AIR-1 in C. elegans embryos. We show that acute inactivation of AIR-1 during mitosis results in excess pulling forces on astral microtubules. Furthermore, we uncover that AIR-1 acts downstream of PPH-6-SAPS-1 in modulating spindle positioning, and that PPH-6-SAPS-1 negatively regulates AIR-1 localization at the cell cortex. Moreover, we show that Aurora A and the PP6 phosphatase subunit PPP6C are also necessary for spindle positioning in human cells. There, Aurora A is needed for the cortical localization of NuMA and dynein during mitosis. Overall, our work demonstrates that Aurora A kinases and PP6 phosphatases have an ancient function in modulating spindle positioning, thus contributing to faithful cell division.
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Affiliation(s)
- Sachin Kotak
- Swiss Institute for Experimental Cancer Research (ISREC), School of Life Sciences, Swiss Federal Institute of Technology (EPFL), Lausanne CH-1015, Switzerland
| | - Katayon Afshar
- Swiss Institute for Experimental Cancer Research (ISREC), School of Life Sciences, Swiss Federal Institute of Technology (EPFL), Lausanne CH-1015, Switzerland
| | - Coralie Busso
- Swiss Institute for Experimental Cancer Research (ISREC), School of Life Sciences, Swiss Federal Institute of Technology (EPFL), Lausanne CH-1015, Switzerland
| | - Pierre Gönczy
- Swiss Institute for Experimental Cancer Research (ISREC), School of Life Sciences, Swiss Federal Institute of Technology (EPFL), Lausanne CH-1015, Switzerland
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26
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Ananthanarayanan V. Activation of the motor protein upon attachment: Anchors weigh in on cytoplasmic dynein regulation. Bioessays 2016; 38:514-25. [PMID: 27143631 DOI: 10.1002/bies.201600002] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Cytoplasmic dynein is the major minus-end-directed motor protein in eukaryotes, and has functions ranging from organelle and vesicle transport to spindle positioning and orientation. The mode of regulation of dynein in the cell remains elusive, but a tantalising possibility is that dynein is maintained in an inhibited, non-motile state until bound to cargo. In vivo, stable attachment of dynein to the cell membrane via anchor proteins enables dynein to produce force by pulling on microtubules and serves to organise the nuclear material. Anchor proteins of dynein assume diverse structures and functions and differ in their interaction with the membrane. In yeast, the anchor protein has come to the fore as one of the key mediators of dynein activity. In other systems, much is yet to be discovered about the anchors, but future work in this area will prove invaluable in understanding dynein regulation in the cell.
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Singh D, Odedra D, Lehmann C, Pohl C. Acute heat shock leads to cortical domain internalization and polarity loss in theC. elegansembryo. Genesis 2016; 54:220-8. [DOI: 10.1002/dvg.22930] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2015] [Revised: 02/26/2016] [Accepted: 02/26/2016] [Indexed: 11/06/2022]
Affiliation(s)
- Deepika Singh
- Buchmann Institute for Molecular Life Sciences and Institute of Biochemistry II, Goethe University; Max-von-Laue-Strasse 15 Frankfurt (Main) 60438 Germany
| | - Devang Odedra
- Buchmann Institute for Molecular Life Sciences and Institute of Biochemistry II, Goethe University; Max-von-Laue-Strasse 15 Frankfurt (Main) 60438 Germany
| | - Christina Lehmann
- Buchmann Institute for Molecular Life Sciences and Institute of Biochemistry II, Goethe University; Max-von-Laue-Strasse 15 Frankfurt (Main) 60438 Germany
| | - Christian Pohl
- Buchmann Institute for Molecular Life Sciences and Institute of Biochemistry II, Goethe University; Max-von-Laue-Strasse 15 Frankfurt (Main) 60438 Germany
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Wu JC, Espiritu EB, Rose LS. The 14-3-3 protein PAR-5 regulates the asymmetric localization of the LET-99 spindle positioning protein. Dev Biol 2016; 412:288-297. [PMID: 26921457 DOI: 10.1016/j.ydbio.2016.02.020] [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: 03/05/2015] [Revised: 02/19/2016] [Accepted: 02/23/2016] [Indexed: 01/03/2023]
Abstract
PAR proteins play important roles in establishing cytoplasmic polarity as well as regulating spindle positioning during asymmetric division. However, the molecular mechanisms by which the PAR proteins generate asymmetry in different cell types are still being elucidated. Previous studies in Caenorhabditis elegans revealed that PAR-3 and PAR-1 regulate the asymmetric localization of LET-99, which in turn controls spindle positioning by affecting the distribution of the conserved force generating complex. In wild-type embryos, LET-99 is localized in a lateral cortical band pattern, via inhibition at the anterior by PAR-3 and at the posterior by PAR-1. In this report, we show that the 14-3-3 protein PAR-5 is also required for cortical LET-99 asymmetry. PAR-5 associated with LET-99 in pull-down assays, and two PAR-5 binding sites were identified in LET-99 using the yeast two-hybrid assay. Mutation of these sites abolished binding in yeast and altered LET-99 localization in vivo: LET-99 was present at the highest levels at the posterior pole of the embryo instead of a band in par-5 embryos. Together the results indicate that PAR-5 acts in a mechanism with PAR-1 to regulate LET-99 cortical localization.
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Affiliation(s)
- Jui-Ching Wu
- Department of Molecular and Cellular Biology, University of California, Davis, USA
| | - Eugenel B Espiritu
- Department of Molecular and Cellular Biology, University of California, Davis, USA
| | - Lesilee S Rose
- Department of Molecular and Cellular Biology, University of California, Davis, USA
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29
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Gallini S, Carminati M, De Mattia F, Pirovano L, Martini E, Oldani A, Asteriti IA, Guarguaglini G, Mapelli M. NuMA Phosphorylation by Aurora-A Orchestrates Spindle Orientation. Curr Biol 2016; 26:458-69. [PMID: 26832443 DOI: 10.1016/j.cub.2015.12.051] [Citation(s) in RCA: 56] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2015] [Revised: 11/30/2015] [Accepted: 12/16/2015] [Indexed: 11/30/2022]
Abstract
Spindle positioning is essential for tissue morphogenesis and homeostasis. The signaling network synchronizing spindle placement with mitotic progression relies on timely recruitment at the cell cortex of NuMA:LGN:Gαi complexes, in which NuMA acts as a receptor for the microtubule motor Dynein. To study the implication of Aurora-A in spindle orientation, we developed protocols for the partial inhibition of its activity. Under these conditions, in metaphase NuMA and Dynein accumulate abnormally at the spindle poles and do not reach the cortex, while the cortical distribution of LGN remains unperturbed. FRAP experiments revealed that Aurora-A governs the dynamic exchange between the cytoplasmic and the spindle pole-localized pools of NuMA. We show that Aurora-A phosphorylates directly the C terminus of NuMA on three Ser residues, of which Ser1969 determines the dynamic behavior and the spindle orientation functions of NuMA. Most interestingly, we identify a new microtubule-binding domain of NuMA, which does not overlap with the LGN-binding motif. Our study demonstrates that in metaphase the direct phosphorylation of NuMA by Aurora-A controls its cortical enrichment, and that this is the major event underlying the spindle orientation functions of Aurora-A in transformed and non-transformed cells in culture. Phosphorylation of NuMA by Aurora-A does not affect its affinity for microtubules or for LGN but rather determines the mobility of the protein at the spindle poles. The finding that NuMA can associate concomitantly with LGN and microtubules suggests that its microtubule-binding activity contributes to anchor Dynein-loaded microtubule +TIPs at cortical sites with LGN.
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Affiliation(s)
- Sara Gallini
- Department of Experimental Oncology, European Institute of Oncology, Via Adamello 16, 20139 Milan, Italy
| | - Manuel Carminati
- Department of Experimental Oncology, European Institute of Oncology, Via Adamello 16, 20139 Milan, Italy
| | - Fabiola De Mattia
- Institute of Molecular Biology and Pathology, CNR National Research Council, c/o Department of Biology and Biotechnology, Sapienza University of Rome, Via degli Apuli 4, 00185 Rome, Italy
| | - Laura Pirovano
- Department of Experimental Oncology, European Institute of Oncology, Via Adamello 16, 20139 Milan, Italy
| | - Emanuele Martini
- Cogentech S.c.a.r.l., Via Adamello 16, 20139 Milan, Italy; IFOM, the FIRC Institute of Molecular Oncology, Via Adamello 16, 20139 Milan, Italy
| | - Amanda Oldani
- Cogentech S.c.a.r.l., Via Adamello 16, 20139 Milan, Italy; IFOM, the FIRC Institute of Molecular Oncology, Via Adamello 16, 20139 Milan, Italy
| | - Italia Anna Asteriti
- Institute of Molecular Biology and Pathology, CNR National Research Council, c/o Department of Biology and Biotechnology, Sapienza University of Rome, Via degli Apuli 4, 00185 Rome, Italy
| | - Giulia Guarguaglini
- Institute of Molecular Biology and Pathology, CNR National Research Council, c/o Department of Biology and Biotechnology, Sapienza University of Rome, Via degli Apuli 4, 00185 Rome, Italy.
| | - Marina Mapelli
- Department of Experimental Oncology, European Institute of Oncology, Via Adamello 16, 20139 Milan, Italy.
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30
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Moorhouse KS, Gudejko HF, McDougall A, Burgess DR. Influence of cell polarity on early development of the sea urchin embryo. Dev Dyn 2015; 244:1469-84. [PMID: 26293695 PMCID: PMC4715636 DOI: 10.1002/dvdy.24337] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2015] [Revised: 08/11/2015] [Accepted: 08/13/2015] [Indexed: 12/25/2022] Open
Abstract
BACKGROUND Establishment and maintenance of cell polarity is critical for normal embryonic development. Previously, it was thought that the echinoderm embryo remained relatively unpolarized until the first asymmetric division at the 16-cell stage. Here, we analyzed roles of the cell polarity regulators, the PAR complex proteins, and how their disruption in early development affects later developmental milestones. RESULTS We found that PAR6, aPKC, and CDC42 localize to the apical cortex as early as the 2-cell stage and that this localization is retained through the gastrula stage. Of interest, PAR1 also colocalizes with these apical markers through the gastrula stage. Additionally, PAR1 was found to be in complex with aPKC, but not PAR6. PAR6, aPKC, and CDC42 are anchored in the cortical actin cytoskeleton by assembled myosin. Furthermore, assembled myosin was found to be necessary to maintain proper PAR6 localization through subsequent cleavage divisions. Interference with myosin assembly prevented the embryos from reaching the blastula stage, while transient disruptions of either actin or microtubules did not have this effect. CONCLUSIONS These observations suggest that disruptions of the polarity in the early embryo can have a significant impact on the ability of the embryo to reach later critical stages in development.
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Affiliation(s)
- Kathleen S. Moorhouse
- Department of Biology, Boston College, Chestnut Hill, Massachusetts
- Marine Biological Laboratory, Woods Hole, Massachusetts
| | - Heather F.M. Gudejko
- Department of Biology, Boston College, Chestnut Hill, Massachusetts
- Marine Biological Laboratory, Woods Hole, Massachusetts
| | - Alex McDougall
- UMR 7009, UPMC Sorbonne Universités, Centre National de la Recherche (CNRS), Observatoire Océanologique, 181 Chemin du Lazaret, 06230 Villefranche-sur-Mer, France
| | - David R. Burgess
- Department of Biology, Boston College, Chestnut Hill, Massachusetts
- Marine Biological Laboratory, Woods Hole, Massachusetts
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31
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Koliou X, Fedonidis C, Kalpachidou T, Mangoura D. Nuclear import mechanism of neurofibromin for localization on the spindle and function in chromosome congression. J Neurochem 2015; 136:78-91. [PMID: 26490262 DOI: 10.1111/jnc.13401] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2015] [Revised: 10/12/2015] [Accepted: 10/15/2015] [Indexed: 12/28/2022]
Abstract
Neurofibromatosis type-1 (NF-1) is caused by mutations in the tumor suppressor gene NF1; its protein product neurofibromin is a RasGTPase-activating protein, a property that has yet to explain aneuploidy, most often observed in astrocytes in NF-1. Here, we provide a mechanistic model for the regulated nuclear import of neurofibromin during the cell cycle and for a role in chromosome congression. Specifically, we demonstrate that neurofibromin, phosphorylated on Ser2808, a residue adjacent to a nuclear localization signal in the C-terminal domain (CTD), by Protein Kinase C-epsilon (PKC-ε), accumulates in a Ran-dependent manner and through binding to lamin in the nucleus at G2 in glioblastoma cells. Furthermore, we identify CTD as a tubulin-binding domain and show that a phosphomimetic substitution of its Ser2808 results in a predominantly nuclear localization. Confocal analysis shows that endogenous neurofibromin localizes on the centrosomes at interphase, as well as on the mitotic spindle, through direct associations with tubulins, in glioblastoma cells and primary astrocytes. More importantly, analysis of mitotic phenotypes after siRNA-mediated depletion shows that acute loss of this tumor suppressor protein leads to aberrant chromosome congression at the metaphase plate. Therefore, neurofibromin protein abundance and nuclear import are mechanistically linked to an error-free chromosome congression. Concerned with neurofibromin's, a tumor suppressor, mechanism of action, we demonstrate in astrocytic cells that its synthesis, phosphorylation by Protein Kinase C-ε on Ser2808 (a residue adjacent to a nuclear localization sequence), and nuclear import are cell cycle-dependent, being maximal at G2. During mitosis, neurofibromin is an integral part of the spindle, while its depletion leads to aberrant chromosome congression, possibly explaining the development of chromosomal instability in Neurofibromatosis type-1. Read the Editorial Highlight for this article on page 11. Cover Image for this issue: doi: 10.1111/jnc.13300.
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Affiliation(s)
- Xeni Koliou
- Basic Research Center, Biomedical Research Foundation of the Academy of Athens, Athens, Greece
| | - Constantinos Fedonidis
- Basic Research Center, Biomedical Research Foundation of the Academy of Athens, Athens, Greece
| | - Theodora Kalpachidou
- Basic Research Center, Biomedical Research Foundation of the Academy of Athens, Athens, Greece
| | - Dimitra Mangoura
- Basic Research Center, Biomedical Research Foundation of the Academy of Athens, Athens, Greece
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32
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Qi R, Xu N, Wang G, Ren H, Li S, Lei J, Lin Q, Wang L, Gu X, Zhang H, Jiang Q, Zhang C. The lamin-A/C-LAP2α-BAF1 protein complex regulates mitotic spindle assembly and positioning. J Cell Sci 2015; 128:2830-41. [PMID: 26092935 DOI: 10.1242/jcs.164566] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2014] [Accepted: 06/15/2015] [Indexed: 01/31/2023] Open
Abstract
Some nuclear proteins that are crucial in interphase relocate during the G2/M-phase transition in order to perform their mitotic functions. However, how they perform these functions and the underlying mechanisms remain largely unknown. Here, we report that a fraction of the nuclear periphery proteins lamin-A/C, LAP2α and BAF1 (also known as BANF1) relocate to the spindle and the cell cortex in mitosis. Knockdown of these proteins by using RNA interference (RNAi) induces short and fluffy spindle formation, and disconnection of the spindle from the cell cortex. Disrupting the microtubule assembly leads to accumulation of these proteins in the cell cortex, whereas depolymerizing the actin microfilaments results in the formation of short spindles. We further demonstrate that these proteins are part of a stable complex that links the mitotic spindle to the cell cortex and the spindle matrix by binding to spindle-associated dynein, the actin filaments in the cell cortex and the spindle matrix. Taken together, our findings unveil a unique mechanism where the nuclear periphery proteins lamin-A/C, LAP2α and BAF1 are assembled into a protein complex during mitosis in order to regulate assembly and positioning of the mitotic spindle.
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Affiliation(s)
- Ran Qi
- The Ministry of Education Key Laboratory of Cell Proliferation and Differentiation and the State Key Laboratory of Membrane Biology, College of Life Sciences, Beijing 100871, China
| | - Nan Xu
- The Ministry of Education Key Laboratory of Cell Proliferation and Differentiation and the State Key Laboratory of Membrane Biology, College of Life Sciences, Beijing 100871, China
| | - Gang Wang
- The Ministry of Education Key Laboratory of Cell Proliferation and Differentiation and the State Key Laboratory of Membrane Biology, College of Life Sciences, Beijing 100871, China
| | - He Ren
- The Ministry of Education Key Laboratory of Cell Proliferation and Differentiation and the State Key Laboratory of Membrane Biology, College of Life Sciences, Beijing 100871, China
| | - Si Li
- The Ministry of Education Key Laboratory of Cell Proliferation and Differentiation and the State Key Laboratory of Membrane Biology, College of Life Sciences, Beijing 100871, China
| | - Jun Lei
- The Ministry of Education Key Laboratory of Cell Proliferation and Differentiation and the State Key Laboratory of Membrane Biology, College of Life Sciences, Beijing 100871, China
| | - Qiaoyu Lin
- The Ministry of Education Key Laboratory of Cell Proliferation and Differentiation and the State Key Laboratory of Membrane Biology, College of Life Sciences, Beijing 100871, China
| | - Lihao Wang
- The Ministry of Education Key Laboratory of Cell Proliferation and Differentiation and the State Key Laboratory of Membrane Biology, College of Life Sciences, Beijing 100871, China
| | - Xin Gu
- The Ministry of Education Key Laboratory of Cell Proliferation and Differentiation and the State Key Laboratory of Membrane Biology, College of Life Sciences, Beijing 100871, China
| | - Hongyin Zhang
- Cancer Research Center, Peking University Hospital, Peking University, Beijing 100871, China
| | - Qing Jiang
- The Ministry of Education Key Laboratory of Cell Proliferation and Differentiation and the State Key Laboratory of Membrane Biology, College of Life Sciences, Beijing 100871, China
| | - Chuanmao Zhang
- The Ministry of Education Key Laboratory of Cell Proliferation and Differentiation and the State Key Laboratory of Membrane Biology, College of Life Sciences, Beijing 100871, China
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Rb and FZR1/Cdh1 determine CDK4/6-cyclin D requirement in C. elegans and human cancer cells. Nat Commun 2015; 6:5906. [PMID: 25562820 PMCID: PMC4354291 DOI: 10.1038/ncomms6906] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2014] [Accepted: 11/19/2014] [Indexed: 01/02/2023] Open
Abstract
Cyclin-dependent kinases 4 and 6 (CDK4/6) in complex with D-type cyclins promote cell cycle entry. Most human cancers contain overactive CDK4/6-cyclin D, and CDK4/6-specific inhibitors are promising anti-cancer therapeutics. Here, we investigate the critical functions of CDK4/6-cyclin D kinases, starting from an unbiased screen in the nematode Caenorhabditis elegans. We found that simultaneous mutation of lin-35, a retinoblastoma (Rb)-related gene, and fzr-1, an orthologue to the APC/C co-activator Cdh1, completely eliminates the essential requirement of CDK4/6-cyclin D (CDK-4/CYD-1) in C. elegans. CDK-4/CYD-1 phosphorylates specific residues in the LIN-35 Rb spacer domain and FZR-1 amino terminus, resembling inactivating phosphorylations of the human proteins. In human breast cancer cells, simultaneous knockdown of Rb and FZR1 synergistically bypasses cell division arrest induced by the CDK4/6-specific inhibitor PD-0332991. Our data identify FZR1 as a candidate CDK4/6-cyclin D substrate and point to an APC/CFZR1 activity as an important determinant in response to CDK4/6-inhibitors. In most human tumours, the cell cycle regulators Cdk4/6-cyclinD are overactive. Here the authors use C. elegans as a model system to identify downstream regulators that are critical in the response of tumour cells to Cdk4/6 inhibitors.
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34
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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.
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35
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Elric J, Etienne-Manneville S. Centrosome positioning in polarized cells: common themes and variations. Exp Cell Res 2014; 328:240-8. [PMID: 25218948 DOI: 10.1016/j.yexcr.2014.09.004] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2014] [Accepted: 09/01/2014] [Indexed: 12/17/2022]
Abstract
The centrosome position is tightly regulated during the cell cycle and during differentiated cellular functions. Because centrosome organizes the microtubule network to coordinate both intracellular organization and cell signaling, centrosome positioning is crucial to determine either the axis of cell division, the direction of cell migration or the polarized immune response of lymphocytes. Since alteration of centrosome positioning seems to promote cell transformation and tumor spreading, the molecular mechanisms controlling centrosome movement in response to extracellular and intracellular cues are under intense investigation. Evolutionary conserved pathways involving polarity proteins and cytoskeletal rearrangements are emerging as common regulators of centrosome positioning in a wide variety of cellular contexts.
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Affiliation(s)
- Julien Elric
- Institut Pasteur - CNRS URA 2582, Cell Polarity, Migration and Cancer Unit, 25 rue du Dr Roux, 75724 Paris Cedex 15, France; Université Pierre et Marie Curie, Cellule Pasteur UPMC, rue du Dr Roux, 75015 Paris, France
| | - Sandrine Etienne-Manneville
- Institut Pasteur - CNRS URA 2582, Cell Polarity, Migration and Cancer Unit, 25 rue du Dr Roux, 75724 Paris Cedex 15, France.
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36
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Herrera A, Saade M, Menendez A, Marti E, Pons S. Sustained Wnt/β-catenin signalling causes neuroepithelial aberrations through the accumulation of aPKC at the apical pole. Nat Commun 2014; 5:4168. [PMID: 24942669 DOI: 10.1038/ncomms5168] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2013] [Accepted: 05/19/2014] [Indexed: 11/09/2022] Open
Abstract
β-Catenin mediates the canonical Wnt pathway by stimulating Tcf-dependent transcription and also associates to N-cadherin at the apical complex (AC) of neuroblasts. Here, we show that while β-catenin activity is required to form the AC and to maintain the cell polarity, oncogenic mutations that render stable forms of β-catenin (sβ-catenin) maintain the stemness of neuroblasts, inhibiting their differentiation and provoking aberrant growth. In examining the transcriptional and structural roles of β-catenin, we find that while β-catenin/Tcf transcriptional activity induces atypical protein kinase C (aPKC) expression, an alternative effect of β-catenin restricts aPKC to the apical pole of neuroepithelial cells. In agreement, we show that a constitutively active form of aPKC reproduces the neuroepithelial aberrations induced by β-catenin. Therefore, we conclude that β-catenin controls the cell fate and polarity of the neuroblasts through the expression and localization of aPKC.
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Affiliation(s)
- Antonio Herrera
- Instituto de Investigaciones Biomédicas de Barcelona, CSIC-IDIBAPS, Rossellò 161, Barcelona 08036, Spain
| | - Murielle Saade
- Instituto de Biología Molecular de Barcelona, CSIC, Parc Científic de Barcelona, Baldiri Reixac 20, Barcelona 08028, Spain
| | - Anghara Menendez
- Instituto de Investigaciones Biomédicas de Barcelona, CSIC-IDIBAPS, Rossellò 161, Barcelona 08036, Spain
| | - Elisa Marti
- Instituto de Biología Molecular de Barcelona, CSIC, Parc Científic de Barcelona, Baldiri Reixac 20, Barcelona 08028, Spain
| | - Sebastian Pons
- 1] Instituto de Investigaciones Biomédicas de Barcelona, CSIC-IDIBAPS, Rossellò 161, Barcelona 08036, Spain [2] Instituto de Biología Molecular de Barcelona, CSIC, Parc Científic de Barcelona, Baldiri Reixac 20, Barcelona 08028, Spain
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37
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Sjöqvist M, Antfolk D, Ferraris S, Rraklli V, Haga C, Antila C, Mutvei A, Imanishi SY, Holmberg J, Jin S, Eriksson JE, Lendahl U, Sahlgren C. PKCζ regulates Notch receptor routing and activity in a Notch signaling-dependent manner. Cell Res 2014; 24:433-50. [PMID: 24662486 DOI: 10.1038/cr.2014.34] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2013] [Revised: 12/17/2013] [Accepted: 12/20/2013] [Indexed: 12/23/2022] Open
Abstract
Activation of Notch signaling requires intracellular routing of the receptor, but the mechanisms controlling the distinct steps in the routing process is poorly understood. We identify PKCζ as a key regulator of Notch receptor intracellular routing. When PKCζ was inhibited in the developing chick central nervous system and in cultured myoblasts, Notch-stimulated cells were allowed to undergo differentiation. PKCζ phosphorylates membrane-tethered forms of Notch and regulates two distinct routing steps, depending on the Notch activation state. When Notch is activated, PKCζ promotes re-localization of Notch from late endosomes to the nucleus and enhances production of the Notch intracellular domain, which leads to increased Notch activity. In the non-activated state, PKCζ instead facilitates Notch receptor internalization, accompanied with increased ubiquitylation and interaction with the endosomal sorting protein Hrs. Collectively, these data identify PKCζ as a key regulator of Notch trafficking and demonstrate that distinct steps in intracellular routing are differentially modulated depending on Notch signaling status.
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Affiliation(s)
- Marika Sjöqvist
- 1] Turku Centre for Biotechnology, University of Turku and Åbo Akademi University, 20520 Turku, Finland [2] Department of Biosciences, Åbo Akademi University, 20520 Turku, Finland
| | - Daniel Antfolk
- 1] Turku Centre for Biotechnology, University of Turku and Åbo Akademi University, 20520 Turku, Finland [2] Department of Biosciences, Åbo Akademi University, 20520 Turku, Finland
| | - Saima Ferraris
- Department of Biosciences, Åbo Akademi University, 20520 Turku, Finland
| | - Vilma Rraklli
- Ludwig Institute for Cancer Research, Karolinska Institute, Box 240, SE-171 77 Stockholm, Sweden
| | - Cecilia Haga
- 1] Turku Centre for Biotechnology, University of Turku and Åbo Akademi University, 20520 Turku, Finland [2] Department of Biosciences, Åbo Akademi University, 20520 Turku, Finland
| | - Christian Antila
- 1] Turku Centre for Biotechnology, University of Turku and Åbo Akademi University, 20520 Turku, Finland [2] Department of Biosciences, Åbo Akademi University, 20520 Turku, Finland
| | - Anders Mutvei
- Department of Cell and Molecular Biology, Karolinska Institutet, SE-171 77 Stockholm, Sweden
| | - Susumu Y Imanishi
- Turku Centre for Biotechnology, University of Turku and Åbo Akademi University, 20520 Turku, Finland
| | - Johan Holmberg
- 1] Ludwig Institute for Cancer Research, Karolinska Institute, Box 240, SE-171 77 Stockholm, Sweden [2] Department of Cell and Molecular Biology, Karolinska Institutet, SE-171 77 Stockholm, Sweden
| | - Shaobo Jin
- Department of Cell and Molecular Biology, Karolinska Institutet, SE-171 77 Stockholm, Sweden
| | - John E Eriksson
- 1] Turku Centre for Biotechnology, University of Turku and Åbo Akademi University, 20520 Turku, Finland [2] Department of Biosciences, Åbo Akademi University, 20520 Turku, Finland
| | - Urban Lendahl
- Department of Cell and Molecular Biology, Karolinska Institutet, SE-171 77 Stockholm, Sweden
| | - Cecilia Sahlgren
- 1] Turku Centre for Biotechnology, University of Turku and Åbo Akademi University, 20520 Turku, Finland [2] Department of Biosciences, Åbo Akademi University, 20520 Turku, Finland [3] Department of Biomedical Engineering, Technical University of Eindhoven, 2612 Eindhoven, The Netherlands
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38
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Ahmed SM, Angers S. Emerging non-canonical functions for heterotrimeric G proteins in cellular signaling. J Recept Signal Transduct Res 2013; 33:177-83. [PMID: 23721574 DOI: 10.3109/10799893.2013.795972] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Classically heterotrimeric G proteins have been described as the principal signal transducing machinery for G-protein-coupled receptors. Receptor activation catalyzes nucleotide exchange on the Gα protein, enabling Gα-GTP and Gβγ-subunits to engage intracellular effectors to generate various cellular effects such as second messenger production or regulation of ion channel conductivity. Recent genetic and proteomic screens have identified novel heterotrimeric G-protein-interacting proteins and expanded their functional roles. This review highlights some examples of recently identified interacting proteins and summarizes how they functionally connect heterotrimeric G proteins to previously underappreciated cellular roles.
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Affiliation(s)
- Syed M Ahmed
- Department of Pharmaceutical Sciences, Leslie Dan Faculty of Pharmacy, University of Toronto, Toronto, ON, Canada
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Akhshi TK, Wernike D, Piekny A. Microtubules and actin crosstalk in cell migration and division. Cytoskeleton (Hoboken) 2013; 71:1-23. [DOI: 10.1002/cm.21150] [Citation(s) in RCA: 110] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2013] [Revised: 10/02/2013] [Accepted: 10/06/2013] [Indexed: 12/22/2022]
Affiliation(s)
| | - Denise Wernike
- Department of Biology; Concordia University; Montreal Quebec Canada
| | - Alisa Piekny
- Department of Biology; Concordia University; Montreal Quebec Canada
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Bergstralh DT, Haack T, St Johnston D. Epithelial polarity and spindle orientation: intersecting pathways. Philos Trans R Soc Lond B Biol Sci 2013; 368:20130291. [PMID: 24062590 PMCID: PMC3785970 DOI: 10.1098/rstb.2013.0291] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
During asymmetric stem cell divisions, the mitotic spindle must be correctly oriented and positioned with respect to the axis of cell polarity to ensure that cell fate determinants are appropriately segregated into only one daughter cell. By contrast, epithelial cells divide symmetrically and orient their mitotic spindles perpendicular to the main apical–basal polarity axis, so that both daughter cells remain within the epithelium. Work in the past 20 years has defined a core ternary complex consisting of Pins, Mud and Gαi that participates in spindle orientation in both asymmetric and symmetric divisions. As additional factors that interact with this complex continue to be identified, a theme has emerged: there is substantial overlap between the mechanisms that orient the spindle and those that establish and maintain apical–basal polarity in epithelial cells. In this review, we examine several factors implicated in both processes, namely Canoe, Bazooka, aPKC and Discs large, and consider the implications of this work on how the spindle is oriented during epithelial cell divisions.
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Affiliation(s)
- Dan T Bergstralh
- The Gurdon Institute and the Department of Genetics, University of Cambridge, , Tennis Court Road, Cambridge CB2 1QN, UK
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41
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Kotak S, Gönczy P. Mechanisms of spindle positioning: cortical force generators in the limelight. Curr Opin Cell Biol 2013; 25:741-8. [PMID: 23958212 DOI: 10.1016/j.ceb.2013.07.008] [Citation(s) in RCA: 138] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2013] [Revised: 07/09/2013] [Accepted: 07/15/2013] [Indexed: 01/04/2023]
Abstract
Correct positioning of the spindle governs placement of the cytokinesis furrow and thus plays a crucial role in the partitioning of fate determinants and the disposition of daughter cells in a tissue. Converging evidence indicates that spindle positioning is often dictated by interactions between the plus-end of astral microtubules that emanate from the spindle poles and an evolutionary conserved cortical machinery that serves to pull on them. At the heart of this machinery lies a ternary complex (LIN-5/GPR-1/2/Gα in Caenorhabditis elegans and NuMA/LGN/Gαi in Homo sapiens) that promotes the presence of the motor protein dynein at the cell cortex. In this review, we discuss how the above components contribute to spindle positioning and how the underlying mechanisms are precisely regulated to ensure the proper execution of this crucial process in metazoan organisms.
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Affiliation(s)
- Sachin Kotak
- Swiss Institute for Experimental Cancer Research (ISREC), School of Life Sciences, Swiss Federal Institute of Technology (EPFL), Lausanne CH-1005, Switzerland
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42
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Mapelli M, Gonzalez C. On the inscrutable role of Inscuteable: structural basis and functional implications for the competitive binding of NuMA and Inscuteable to LGN. Open Biol 2013; 2:120102. [PMID: 22977735 PMCID: PMC3438535 DOI: 10.1098/rsob.120102] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2012] [Accepted: 07/20/2012] [Indexed: 11/12/2022] Open
Abstract
Alignment of the mitotic spindle to the cellular polarity axis is a prerequisite for asymmetric cell divisions. The protein network coordinating the spindle position with cortical polarity includes the molecular machinery pulling on astral microtubules, which is assembled on conserved NuMA:LGN:Gαi complexes, the polarity proteins Par3:Par6:aPKC and an adaptor molecule known as Inscuteable (Insc). To date, all these components were assumed to enter a macromolecular complex localized at polarity sites in mitosis. However, recent structural studies revealed the Insc and NuMA are mutually exclusive interactors of LGN, implying that the molecular mechanism of spindle coupling to polarity is more sophisticated than has been believed to date.
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Affiliation(s)
- Marina Mapelli
- Department of Experimental Oncology, European Institute of Oncology, Via Adamello 16, 20139 Milan, Italy.
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Abstract
The centrosome, a major organizer of microtubules, has important functions in regulating cell shape, polarity, cilia formation and intracellular transport as well as the position of cellular structures, including the mitotic spindle. By means of these activities, centrosomes have important roles during animal development by regulating polarized cell behaviors, such as cell migration or neurite outgrowth, as well as mitotic spindle orientation. In recent years, the pace of discovery regarding the structure and composition of centrosomes has continuously accelerated. At the same time, functional studies have revealed the importance of centrosomes in controlling both morphogenesis and cell fate decision during tissue and organ development. Here, we review examples of centrosome and centriole positioning with a particular emphasis on vertebrate developmental systems, and discuss the roles of centrosome positioning, the cues that determine positioning and the mechanisms by which centrosomes respond to these cues. The studies reviewed here suggest that centrosome functions extend to the development of tissues and organs in vertebrates.
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Affiliation(s)
- Nan Tang
- Department of Anatomy, Cardiovascular Research Institute, The University of California, San Francisco, USA.
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Berends CWH, Muñoz J, Portegijs V, Schmidt R, Grigoriev I, Boxem M, Akhmanova A, Heck AJR, van den Heuvel S. F-actin asymmetry and the endoplasmic reticulum-associated TCC-1 protein contribute to stereotypic spindle movements in the Caenorhabditis elegans embryo. Mol Biol Cell 2013; 24:2201-15. [PMID: 23699393 PMCID: PMC3708726 DOI: 10.1091/mbc.e13-02-0076] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
The position of the spindle apparatus determines the plane of cell cleavage and, therefore, the size and position of daughter cells, as well as the decision between symmetric and asymmetric cell division. We show that asymmetry in cortical actin and, remarkably, an endoplasmic reticulum–localized protein contribute to proper spindle positioning in the Caenorhabditis elegans embryo. The microtubule spindle apparatus dictates the plane of cell cleavage in animal cells. During development, dividing cells control the position of the spindle to determine the size, location, and fate of daughter cells. Spindle positioning depends on pulling forces that act between the cell periphery and astral microtubules. This involves dynein recruitment to the cell cortex by a heterotrimeric G-protein α subunit in complex with a TPR-GoLoco motif protein (GPR-1/2, Pins, LGN) and coiled-coil protein (LIN-5, Mud, NuMA). In this study, we searched for additional factors that contribute to spindle positioning in the one-cell Caenorhabditis elegans embryo. We show that cortical actin is not needed for Gα–GPR–LIN-5 localization and pulling force generation. Instead, actin accumulation in the anterior actually reduces pulling forces, possibly by increasing cortical rigidity. Examining membrane-associated proteins that copurified with GOA-1 Gα, we found that the transmembrane and coiled-coil domain protein 1 (TCC-1) contributes to proper spindle movements. TCC-1 localizes to the endoplasmic reticulum membrane and interacts with UNC-116 kinesin-1 heavy chain in yeast two-hybrid assays. RNA interference of tcc-1 and unc-116 causes similar defects in meiotic spindle positioning, supporting the concept of TCC-1 acting with kinesin-1 in vivo. These results emphasize the contribution of membrane-associated and cortical proteins other than Gα–GPR–LIN-5 in balancing the pulling forces that position the spindle during asymmetric cell division.
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Riche S, Zouak M, Argoul F, Arneodo A, Pecreaux J, Delattre M. Evolutionary comparisons reveal a positional switch for spindle pole oscillations in Caenorhabditis embryos. ACTA ACUST UNITED AC 2013; 201:653-62. [PMID: 23690175 PMCID: PMC3664713 DOI: 10.1083/jcb.201210110] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
In one-cell stage embryos of different worm species, a conserved positional switch controls the onset of mitotic spindle oscillations, whereas the maximum amplitude of oscillations is determined by the time spent in the oscillating phase. During the first embryonic division in Caenorhabditis elegans, the mitotic spindle is pulled toward the posterior pole of the cell and undergoes vigorous transverse oscillations. We identified variations in spindle trajectories by analyzing the outwardly similar one-cell stage embryo of its close relative Caenorhabditis briggsae. Compared with C. elegans, C. briggsae embryos exhibit an anterior shifting of nuclei in prophase and reduced anaphase spindle oscillations. By combining physical perturbations and mutant analysis in both species, we show that differences can be explained by interspecies changes in the regulation of the cortical Gα–GPR–LIN-5 complex. However, we found that in both species (1) a conserved positional switch controls the onset of spindle oscillations, (2) GPR posterior localization may set this positional switch, and (3) the maximum amplitude of spindle oscillations is determined by the time spent in the oscillating phase. By investigating microevolution of a subcellular process, we identify new mechanisms that are instrumental to decipher spindle positioning.
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Affiliation(s)
- Soizic Riche
- Laboratory of Molecular Biology of the Cell, UMR5239, Ecole Normale Supérieure de Lyon, Centre National de la Recherche Scientifique, 69007 Lyon, France
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46
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Using C. elegans to Decipher the Cellular and Molecular Mechanisms Underlying Neurodevelopmental Disorders. Mol Neurobiol 2013; 48:465-89. [DOI: 10.1007/s12035-013-8434-6] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2012] [Accepted: 02/26/2013] [Indexed: 10/27/2022]
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Buchholz VR, Gräf P, Busch DH. The smallest unit: effector and memory CD8(+) T cell differentiation on the single cell level. Front Immunol 2013; 4:31. [PMID: 23424063 PMCID: PMC3573211 DOI: 10.3389/fimmu.2013.00031] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2012] [Accepted: 01/26/2013] [Indexed: 12/16/2022] Open
Abstract
CD8+ T cell immune responses provide immediate protection against primary infection and durable memory capable of rapidly fighting off re-infection. Immediate protection and lasting memory are implemented by phenotypically and functionally distinct T cell subsets. While it is now widely accepted that these diverge from a common source of naïve T cells (Tn), the developmental relation and succession of effector and memory T cell subsets is still under intense debate. Recently, a distinct memory T cell subset has been suggested to possess stem cell-like features, sparking the hope to harness its capacity for self-renewal and diversification for successful therapy of chronic infections or malignant diseases. In this review we highlight current developmental models of memory generation, T cell subset diversification and T cell stemness. We discuss the importance of single cell monitoring techniques for adequately mapping these developmental processes and take a brief look at signaling components active in the putative stem cell-like memory T cell compartment.
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Affiliation(s)
- Veit R Buchholz
- Institute for Medical Microbiology, Immunology and Hygiene, Technische Universität München Munich, Germany
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Abstract
Cell polarity is crucial for many functions including cell migration, tissue organization and asymmetric cell division. In animal cells, cell polarity is controlled by the highly conserved PAR (PARtitioning defective) proteins. par genes have been identified in Caenorhabditis elegans in screens for maternal lethal mutations that disrupt cytoplasmic partitioning and asymmetric division. Although PAR proteins were identified more than 20 years ago, our understanding on how they regulate polarity and how they are regulated is still incomplete. In this chapter we review our knowledge of the processes of cell polarity establishment and maintenance, and asymmetric cell division in the early C. elegans embryo. We discuss recent findings that highlight new players in cell polarity and/or reveal the molecular details on how PAR proteins regulate polarity processes.
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Altelaar AFM, Munoz J, Heck AJR. Next-generation proteomics: towards an integrative view of proteome dynamics. Nat Rev Genet 2012. [PMID: 23207911 DOI: 10.1038/nrg3356] [Citation(s) in RCA: 515] [Impact Index Per Article: 42.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Next-generation sequencing allows the analysis of genomes, including those representing disease states. However, the causes of most disorders are multifactorial, and systems-level approaches, including the analysis of proteomes, are required for a more comprehensive understanding. The proteome is extremely multifaceted owing to splicing and protein modifications, and this is further amplified by the interconnectivity of proteins into complexes and signalling networks that are highly divergent in time and space. Proteome analysis heavily relies on mass spectrometry (MS). MS-based proteomics is starting to mature and to deliver through a combination of developments in instrumentation, sample preparation and computational analysis. Here we describe this emerging next generation of proteomics and highlight recent applications.
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Affiliation(s)
- A F Maarten Altelaar
- Biomolecular Mass Spectrometry and Proteomics, Bijvoet Center for Biomolecular Research and Utrecht Institute for Pharmaceutical Sciences, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands
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50
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Abstract
Nearly every cell type exhibits some form of polarity, yet the molecular mechanisms vary widely. Here we examine what we term 'chemical systems' where cell polarization arises through biochemical interactions in signaling pathways, 'mechanical systems' where cells polarize due to forces, stresses and transport, and 'mechanochemical systems' where polarization results from interplay between mechanics and chemical signaling. To reveal potentially unifying principles, we discuss mathematical conceptualizations of several prototypical examples. We suggest that the concept of local activation and global inhibition - originally developed to explain spatial patterning in reaction-diffusion systems - provides a framework for understanding many cases of cell polarity. Importantly, we find that the core ingredients in this framework - symmetry breaking, self-amplifying feedback, and long-range inhibition - involve processes that can be chemical, mechanical, or even mechanochemical in nature.
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