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Starr DA. A network of nuclear envelope proteins and cytoskeletal force generators mediates movements of and within nuclei throughout Caenorhabditis elegans development. Exp Biol Med (Maywood) 2019; 244:1323-1332. [PMID: 31495194 PMCID: PMC6880151 DOI: 10.1177/1535370219871965] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Nuclear migration and anchorage, together referred to as nuclear positioning, are central to many cellular and developmental events. Nuclear positioning is mediated by a conserved network of nuclear envelope proteins that interacts with force generators in the cytoskeleton. At the heart of this network are li nker of n ucleoskeleton and c ytoskeleton (LINC) complexes made of S ad1 and UN C-84 (SUN) proteins at the inner nuclear membrane and K larsicht, A NC-1, and S yne homology (KASH) proteins in the outer nuclear membrane. LINC complexes span the nuclear envelope, maintain nuclear envelope architecture, designate the surface of nuclei distinctly from the contiguous endoplasmic reticulum, and were instrumental in the early evolution of eukaryotes. LINC complexes interact with lamins in the nucleus and with various cytoplasmic KASH effectors from the surface of nuclei. These effectors regulate the cytoskeleton, leading to a variety of cellular outputs including pronuclear migration, nuclear migration through constricted spaces, nuclear anchorage, centrosome attachment to nuclei, meiotic chromosome movements, and DNA damage repair. How LINC complexes are regulated and how they function are reviewed here. The focus is on recent studies elucidating the best-understood network of LINC complexes, those used throughout Caenorhabditis elegans development.
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Affiliation(s)
- Daniel A Starr
- Department of Molecular and Cellular Biology,
University of California, Davis, CA 95616, USA
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2
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Tocco VJ, Neelam S, Zhang Q, Dickinson RB, Lele TP. Direct Force Probe for Nuclear Mechanics. Methods Mol Biol 2018; 1840:81-90. [PMID: 30141040 DOI: 10.1007/978-1-4939-8691-0_8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
Abstract
We describe a recently reported method for directly applying a known, nanonewton-scale force to the nucleus in a living, intact cell. First, a suction seal is applied on the nuclear surface using a micropipette. Then, the micropipette is translated away from the nucleus. The nucleus deforms and translates with the moving micropipette and then eventually detaches from the micropipette and recovers (roughly) its original shape and position. At the point of detachment, the resisting force (from the deformed nucleus and connected cytoskeleton) balances the suction force. Because the suction force is precisely known and reproducibly applied, this method therefore allows comparisons of nuclear response across disruptions to the cytoskeleton, nucleus, or cell. This method is useful for quantifying nuclear elastic properties in its native, integrated environment.
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Chuang M, Hsiao TI, Tong A, Xu S, Chisholm AD. DAPK interacts with Patronin and the microtubule cytoskeleton in epidermal development and wound repair. eLife 2016; 5. [PMID: 27661253 PMCID: PMC5053806 DOI: 10.7554/elife.15833] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2016] [Accepted: 09/22/2016] [Indexed: 12/11/2022] Open
Abstract
Epidermal barrier epithelia form a first line of defense against the environment, protecting animals against infection and repairing physical damage. In C. elegans, death-associated protein kinase (DAPK-1) regulates epidermal morphogenesis, innate immunity and wound repair. Combining genetic suppressor screens and pharmacological tests, we find that DAPK-1 maintains epidermal tissue integrity through regulation of the microtubule (MT) cytoskeleton. dapk-1 epidermal phenotypes are suppressed by treatment with microtubule-destabilizing drugs and mimicked or enhanced by microtubule-stabilizing drugs. Loss of function in ptrn-1, the C. elegans member of the Patronin/Nezha/CAMSAP family of MT minus-end binding proteins, suppresses dapk-1 epidermal and innate immunity phenotypes. Over-expression of the MT-binding CKK domain of PTRN-1 triggers epidermal and immunity defects resembling those of dapk-1 mutants, and PTRN-1 localization is regulated by DAPK-1. DAPK-1 and PTRN-1 physically interact in co-immunoprecipitation experiments, and DAPK-1 itself undergoes MT-dependent transport. Our results uncover an unexpected interdependence of DAPK-1 and the microtubule cytoskeleton in maintenance of epidermal integrity.
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Affiliation(s)
- Marian Chuang
- Section of Cell and Developmental Biology, Division of Biological Sciences, University of California, San Diego, San Diego, United States
| | - Tiffany I Hsiao
- Section of Cell and Developmental Biology, Division of Biological Sciences, University of California, San Diego, San Diego, United States
| | - Amy Tong
- Section of Cell and Developmental Biology, Division of Biological Sciences, University of California, San Diego, San Diego, United States
| | - Suhong Xu
- Section of Cell and Developmental Biology, Division of Biological Sciences, University of California, San Diego, San Diego, United States
| | - Andrew D Chisholm
- Section of Cell and Developmental Biology, Division of Biological Sciences, University of California, San Diego, San Diego, United States
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Quintin S, Gally C, Labouesse M. Noncentrosomal microtubules in C. elegans epithelia. Genesis 2016; 54:229-42. [PMID: 26789944 DOI: 10.1002/dvg.22921] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2015] [Revised: 01/12/2016] [Accepted: 01/14/2016] [Indexed: 11/12/2022]
Abstract
The microtubule cytoskeleton has a dual contribution to cell organization. First, microtubules help displace chromosomes and provide tracks for organelle transport. Second, microtubule rigidity confers specific mechanical properties to cells, which are crucial in cilia or mechanosensory structures. Here we review the recently uncovered organization and functions of noncentrosomal microtubules in C. elegans epithelia, focusing on how they contribute to nuclear positioning and protein transport. In addition, we describe recent data illustrating how the microtubule and actin cytoskeletons interact to achieve those functions.
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Affiliation(s)
- Sophie Quintin
- Development and Stem Cells Department, IGBMC - CNRS UMR 7104/INSERM U964/Université de Strasbourg, 1 Rue Laurent Fries, Illkirch, 67400, France
| | - Christelle Gally
- Development and Stem Cells Department, IGBMC - CNRS UMR 7104/INSERM U964/Université de Strasbourg, 1 Rue Laurent Fries, Illkirch, 67400, France
| | - Michel Labouesse
- Université Pierre Et Marie Curie, IBPS, CNRS UMR7622, 7 Quai St-Bernard, Paris, 75005, France
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Neelam S, Chancellor TJ, Li Y, Nickerson JA, Roux KJ, Dickinson RB, Lele TP. Direct force probe reveals the mechanics of nuclear homeostasis in the mammalian cell. Proc Natl Acad Sci U S A 2015; 112:5720-5. [PMID: 25901323 DOI: 10.1073/pnas.1502111112] [Citation(s) in RCA: 95] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
How cells maintain nuclear shape and position against various intracellular and extracellular forces is not well understood, although defects in nuclear mechanical homeostasis are associated with a variety of human diseases. We estimated the force required to displace and deform the nucleus in adherent living cells with a technique to locally pull the nuclear surface. A minimum pulling force of a few nanonewtons--far greater than typical intracellular motor forces--was required to significantly displace and deform the nucleus. Upon force removal, the original shape and position were restored quickly within a few seconds. This stiff, elastic response required the presence of vimentin, lamin A/C, and SUN (Sad1p, UNC-84)-domain protein linkages, but not F-actin or microtubules. Although F-actin and microtubules are known to exert mechanical forces on the nuclear surface through molecular motor activity, we conclude that the intermediate filament networks maintain nuclear mechanical homeostasis against localized forces.
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Bone CR, Tapley EC, Gorjánácz M, Starr DA. The Caenorhabditis elegans SUN protein UNC-84 interacts with lamin to transfer forces from the cytoplasm to the nucleoskeleton during nuclear migration. Mol Biol Cell 2014; 25:2853-65. [PMID: 25057012 PMCID: PMC4161519 DOI: 10.1091/mbc.e14-05-0971] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
The nucleoplasmic domain of the Caenorhabditis elegans SUN protein UNC-84 interacts with lamin. If this interaction is disrupted, a partial failure in nuclear migration occurs. Nuclear migration is a critical component of many cellular and developmental processes. The nuclear envelope forms a barrier between the cytoplasm, where mechanical forces are generated, and the nucleoskeleton. The LINC complex consists of KASH proteins in the outer nuclear membrane and SUN proteins in the inner nuclear membrane that bridge the nuclear envelope. How forces are transferred from the LINC complex to the nucleoskeleton is poorly understood. The Caenorhabditis elegans lamin, LMN-1, is required for nuclear migration and interacts with the nucleoplasmic domain of the SUN protein UNC-84. This interaction is weakened by the unc-84(P91S) missense mutation. These mutant nuclei have an intermediate nuclear migration defect—live imaging of nuclei or LMN-1::GFP shows that many nuclei migrate normally, others initiate migration before subsequently failing, and others fail to begin migration. At least one other component of the nucleoskeleton, the NET5/Samp1/Ima1 homologue SAMP-1, plays a role in nuclear migration. We propose a nut-and-bolt model to explain how forces are dissipated across the nuclear envelope during nuclear migration. In this model, SUN/KASH bridges serve as bolts through the nuclear envelope, and nucleoskeleton components LMN-1 and SAMP-1 act as both nuts and washers on the inside of the nucleus.
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Affiliation(s)
- Courtney R Bone
- Department of Molecular and Cellular Biology, University of California, Davis, Davis, CA 95618
| | - Erin C Tapley
- Department of Molecular and Cellular Biology, University of California, Davis, Davis, CA 95618
| | - Mátyás Gorjánácz
- European Molecular Biology Laboratory, 69117 Heidelberg, Germany
| | - Daniel A Starr
- Department of Molecular and Cellular Biology, University of California, Davis, Davis, CA 95618
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Burakov AV, Nadezhdina ES. Association of nucleus and centrosome: magnet or velcro? Cell Biol Int 2013; 37:95-104. [DOI: 10.1002/cbin.10016] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2012] [Accepted: 11/12/2012] [Indexed: 12/20/2022]
Affiliation(s)
- Anton V. Burakov
- A.N.Belozersky Institute of Physico-Chemical Biology of Lomonosov Moscow State University; Vorobjevy Gory, 1/40, Moscow 119992 Russia
| | - Elena S. Nadezhdina
- A.N.Belozersky Institute of Physico-Chemical Biology of Lomonosov Moscow State University; Vorobjevy Gory, 1/40, Moscow 119992 Russia
- Institute of Protein Research of Russian Academy of Science; Vavilova ul., 34, Moscow 119333 Russia
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Abstract
BioArchitecture is a term used to describe the organization and regulation of biological space. It applies to the principles which govern the structure of molecules, polymers and mutiprotein complexes, organelles, membranes and their organization in the cytoplasm and the nucleus. It also covers the integration of cells into their three dimensional environment at the level of cell-matrix, cell-cell interactions, integration into tissue/organ structure and function and finally into the structure of the organism. This review will highlight studies at all these levels which are providing a new way to think about the relationship between the organization of biological space and the function of biological systems.
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Affiliation(s)
- Peter Gunning
- School of Medical Sciences, University of New South Wales, Sydney, Australia.
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Sharanya D, Thillainathan B, Marri S, Bojanala N, Taylor J, Flibotte S, Moerman DG, Waterston RH, Gupta BP. Genetic control of vulval development in Caenorhabditis briggsae. G3 (Bethesda) 2012; 2:1625-41. [PMID: 23275885 PMCID: PMC3516484 DOI: 10.1534/g3.112.004598] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/31/2012] [Accepted: 10/19/2012] [Indexed: 01/23/2023]
Abstract
The nematode Caenorhabditis briggsae is an excellent model organism for the comparative analysis of gene function and developmental mechanisms. To study the evolutionary conservation and divergence of genetic pathways mediating vulva formation, we screened for mutations in C. briggsae that cause the egg-laying defective (Egl) phenotype. Here, we report the characterization of 13 genes, including three that are orthologs of Caenorhabditis elegans unc-84 (SUN domain), lin-39 (Dfd/Scr-related homeobox), and lin-11 (LIM homeobox). Based on the morphology and cell fate changes, the mutants were placed into four different categories. Class 1 animals have normal-looking vulva and vulva-uterine connections, indicating defects in other components of the egg-laying system. Class 2 animals frequently lack some or all of the vulval precursor cells (VPCs) due to defects in the migration of P-cell nuclei into the ventral hypodermal region. Class 3 animals show inappropriate fusion of VPCs to the hypodermal syncytium, leading to a reduced number of vulval progeny. Finally, class 4 animals exhibit abnormal vulval invagination and morphology. Interestingly, we did not find mutations that affect VPC induction and fates. Our work is the first study involving the characterization of genes in C. briggsae vulva formation, and it offers a basis for future investigations of these genes in C. elegans.
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Affiliation(s)
- Devika Sharanya
- Department of Biology, McMaster University, Hamilton, Ontario L8S 4K1, Canada
| | | | - Sujatha Marri
- Department of Biology, McMaster University, Hamilton, Ontario L8S 4K1, Canada
| | | | - Jon Taylor
- Michael Smith Laboratories, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada
| | - Stephane Flibotte
- Michael Smith Laboratories, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada
| | - Donald G. Moerman
- Michael Smith Laboratories, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada
- Department of Zoology, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada
| | - Robert H. Waterston
- Department of Genome Sciences, University of Washington, Seattle, Washington 98195-5065
| | - Bhagwati P. Gupta
- Department of Biology, McMaster University, Hamilton, Ontario L8S 4K1, Canada
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10
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Abstract
The microtubule network dictates much of the spatial patterning of the cytoplasm, and the coupling of microtubules to membranes controls the structure and positioning of organelles and directs membrane trafficking between them. The connection between membranes and the microtubule cytoskeleton, and the way in which organelles are shaped and moved by interactions with the cytoskeleton, have been studied intensively in recent years. In particular, recent work has expanded our thinking of this topic to include the mechanisms by which membranes are shaped and how cargo is selected for trafficking as a result of coupling to the cytoskeleton. In this Commentary, I will discuss the molecular basis for membrane-motor coupling and the physiological outcomes of this coupling, including the way in which microtubule-based motors affect membrane structure, cargo sorting and vectorial trafficking between organelles. Whereas many core concepts of these processes are now well understood, key questions remain about how the coupling of motors to membranes is established and controlled, about the regulation of cargo and/or motor loading and about the control of directionality.
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Affiliation(s)
- David J Stephens
- Cell Biology Laboratories, School of Biochemistry, University of Bristol, Medical Sciences Building, University Walk, Bristol BS8 1TD, UK.
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