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Winter L, Kustermann M, Ernhofer B, Höger H, Bittner RE, Schmidt WM. Proteins implicated in muscular dystrophy and cancer are functional constituents of the centrosome. Life Sci Alliance 2022; 5:5/11/e202201367. [PMID: 35790299 PMCID: PMC9259872 DOI: 10.26508/lsa.202201367] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2022] [Revised: 06/21/2022] [Accepted: 06/22/2022] [Indexed: 12/02/2022] Open
Abstract
This study demonstrates that the muscular dystrophy-associated proteins dystrophin, utrophin, dysferlin, and calpain-3 localize to the centrosome and that their absence leads to excess centrosomes, compromised nuclear morphology, impaired centrosome orientation, and defective microtubule nucleation. Aberrant expression of dystrophin, utrophin, dysferlin, or calpain-3 was originally identified in muscular dystrophies (MDs). Increasing evidence now indicates that these proteins might act as tumor suppressors in myogenic and non-myogenic cancers. As DNA damage and somatic aneuploidy, hallmarks of cancer, are early pathological signs in MDs, we hypothesized that a common pathway might involve the centrosome. Here, we show that dystrophin, utrophin, dysferlin, and calpain-3 are functional constituents of the centrosome. In myoblasts, lack of any of these proteins caused excess centrosomes, centrosome misorientation, nuclear abnormalities, and impaired microtubule nucleation. In dystrophin double-mutants, these defects were significantly aggravated. Moreover, we demonstrate that also in non-myogenic cells, all four MD-related proteins localize to the centrosome, including the muscle-specific full-length dystrophin isoform. Therefore, MD-related proteins might share a convergent function at the centrosome in addition to their diverse, well-established muscle-specific functions. Thus, our findings support the notion that cancer-like centrosome-related defects underlie MDs and establish a novel concept linking MDs to cancer.
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Affiliation(s)
- Lilli Winter
- Neuromuscular Research Department, Center for Anatomy and Cell Biology, Medical University of Vienna, Vienna, Austria
| | - Monika Kustermann
- Neuromuscular Research Department, Center for Anatomy and Cell Biology, Medical University of Vienna, Vienna, Austria
| | - Büsra Ernhofer
- Neuromuscular Research Department, Center for Anatomy and Cell Biology, Medical University of Vienna, Vienna, Austria
| | - Harald Höger
- Division for Laboratory Animal Science and Genetics, Medical University of Vienna, Himberg, Austria
| | - Reginald E Bittner
- Neuromuscular Research Department, Center for Anatomy and Cell Biology, Medical University of Vienna, Vienna, Austria
| | - Wolfgang M Schmidt
- Neuromuscular Research Department, Center for Anatomy and Cell Biology, Medical University of Vienna, Vienna, Austria
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2
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Janota CS, Pinto A, Pezzarossa A, Machado P, Costa J, Campinho P, Franco CA, Gomes ER. Shielding of actin by the endoplasmic reticulum impacts nuclear positioning. Nat Commun 2022; 13:2763. [PMID: 35589708 PMCID: PMC9120458 DOI: 10.1038/s41467-022-30388-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2021] [Accepted: 04/28/2022] [Indexed: 11/09/2022] Open
Abstract
Nuclear position is central to cell polarization, and its disruption is associated with various pathologies. The nucleus is moved away from the leading edge of migrating cells through its connection to moving dorsal actin cables, and the absence of connections to immobile ventral stress fibers. It is unclear how these asymmetric nucleo-cytoskeleton connections are established. Here, using an in vitro wound assay, we find that remodeling of endoplasmic reticulum (ER) impacts nuclear positioning through the formation of a barrier that shields immobile ventral stress fibers. The remodeling of ER and perinuclear ER accumulation is mediated by the ER shaping protein Climp-63. Furthermore, ectopic recruitment of the ER to stress fibers restores nuclear positioning in the absence of Climp-63. Our findings suggest that the ER mediates asymmetric nucleo-cytoskeleton connections to position the nucleus.
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Affiliation(s)
- Cátia Silva Janota
- Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal
| | - Andreia Pinto
- Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal.,Royal Brompton Hospital and Harefield NHS Foundation Trust, London, UK
| | - Anna Pezzarossa
- Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal.,Champalimaud Foundation, Champalimaud Centre for the Unknown, Lisbon, Portugal
| | - Pedro Machado
- Electron Microscopy Core Facility (EMCF), European Molecular Biology Laboratory, Heidelberg, Germany.,Centre for Ultrastructural Imaging, King's College London, London, UK
| | - Judite Costa
- Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal
| | - Pedro Campinho
- Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal.,Champalimaud Foundation, Champalimaud Centre for the Unknown, Lisbon, Portugal
| | - Cláudio A Franco
- Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal.,Instituto de Histologia e Biologia do Desenvolvimento, Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal
| | - Edgar R Gomes
- Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal. .,Instituto de Histologia e Biologia do Desenvolvimento, Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal.
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3
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Calero-Cuenca FJ, Osorio DS, Carvalho-Marques S, Sridhara SC, Oliveira LM, Jiao Y, Diaz J, Janota CS, Cadot B, Gomes ER. Ctdnep1 and Eps8L2 regulate dorsal actin cables for nuclear positioning during cell migration. Curr Biol 2021; 31:1521-1530.e8. [PMID: 33567288 PMCID: PMC8043254 DOI: 10.1016/j.cub.2021.01.007] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2019] [Revised: 11/12/2020] [Accepted: 01/06/2021] [Indexed: 11/30/2022]
Abstract
Cells actively position their nuclei within the cytoplasm for multiple cellular and physiological functions.1, 2, 3 Consequently, nuclear mispositioning is usually associated with cell dysfunction and disease, from muscular disorders to cancer metastasis.4, 5, 6, 7 Different cell types position their nuclei away from the leading edge during cell migration.8, 9, 10, 11 In migrating fibroblasts, nuclear positioning is driven by an actin retrograde flow originated at the leading edge that drives dorsal actin cables away from the leading edge. The dorsal actin cables connect to the nuclear envelope by the linker of nucleoskeleton and cytoskeleton (LINC) complex on transmembrane actin-associated nuclear (TAN) lines.12, 13, 14 Dorsal actin cables are required for the formation of TAN lines. How dorsal actin cables are organized to promote TAN lines formation is unknown. Here, we report a role for Ctdnep1/Dullard, a nuclear envelope phosphatase,15, 16, 17, 18, 19, 20, 21, 22 and the actin regulator Eps8L223, 24, 25 on nuclear positioning and cell migration. We demonstrate that Ctdnep1 and Eps8L2 directly interact, and this interaction is important for nuclear positioning and cell migration. We also show that Ctdnep1 and Eps8L2 are involved in the formation and thickness of dorsal actin cables required for TAN lines engagement during nuclear movement. We propose that Ctdnep1-Eps8L2 interaction regulates dorsal actin cables for nuclear movement during cell migration. Ctdnep1 and Eps8L2 are required for nuclear positioning and TAN lines formation Ctdnep1 directly interacts with Eps8L2 for nuclear movement and cell migration Ctdnep1-Eps8L2 interaction regulates dorsal actin organization
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Affiliation(s)
- Francisco J Calero-Cuenca
- Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina da Universidade de Lisboa, Avenida Professor Egas Moniz, 1649-028 Lisboa, Portugal
| | - Daniel S Osorio
- Center for Research in Myology, INSERM U974, CNRS FRE3617, Université Pierre et Marie Curie, Sorbonne Universités, GH Pitié Salpêtrière, 75013 Paris, France
| | - Sofia Carvalho-Marques
- Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina da Universidade de Lisboa, Avenida Professor Egas Moniz, 1649-028 Lisboa, Portugal
| | - Sreerama Chaitanya Sridhara
- Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina da Universidade de Lisboa, Avenida Professor Egas Moniz, 1649-028 Lisboa, Portugal
| | - Luis M Oliveira
- Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina da Universidade de Lisboa, Avenida Professor Egas Moniz, 1649-028 Lisboa, Portugal
| | - Yue Jiao
- Center for Research in Myology, INSERM U974, CNRS FRE3617, Université Pierre et Marie Curie, Sorbonne Universités, GH Pitié Salpêtrière, 75013 Paris, France
| | - Jheimmy Diaz
- Center for Research in Myology, INSERM U974, CNRS FRE3617, Université Pierre et Marie Curie, Sorbonne Universités, GH Pitié Salpêtrière, 75013 Paris, France
| | - Cátia S Janota
- Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina da Universidade de Lisboa, Avenida Professor Egas Moniz, 1649-028 Lisboa, Portugal
| | - Bruno Cadot
- Center for Research in Myology, INSERM U974, CNRS FRE3617, Université Pierre et Marie Curie, Sorbonne Universités, GH Pitié Salpêtrière, 75013 Paris, France
| | - Edgar R Gomes
- Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina da Universidade de Lisboa, Avenida Professor Egas Moniz, 1649-028 Lisboa, Portugal; Center for Research in Myology, INSERM U974, CNRS FRE3617, Université Pierre et Marie Curie, Sorbonne Universités, GH Pitié Salpêtrière, 75013 Paris, France; Instituto de Histologia e Biologia do Desenvolvimento, Faculdade de Medicina, Universidade de Lisboa, Avenida Professor Egas Moniz, 1649-028 Lisboa, Portugal.
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4
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Lim SM, Cruz VE, Antoku S, Gundersen GG, Schwartz TU. Structures of FHOD1-Nesprin1/2 complexes reveal alternate binding modes for the FH3 domain of formins. Structure 2021; 29:540-552.e5. [PMID: 33472039 DOI: 10.1016/j.str.2020.12.013] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2020] [Revised: 11/23/2020] [Accepted: 12/21/2020] [Indexed: 12/12/2022]
Abstract
The nuclear position in eukaryotes is controlled by a nucleo-cytoskeletal network, critical in cell differentiation, division, and movement. Forces are transmitted through conserved Linker of Nucleoskeleton and Cytoskeleton (LINC) complexes that traverse the nuclear envelope and engage on either side of the membrane with diverse binding partners. Nesprin-2-giant (Nes2G), a LINC element in the outer nuclear membrane, connects to the actin directly as well as through FHOD1, a formin primarily involved in actin bundling. Here, we report the crystal structure of Nes2G bound to FHOD1 and show that the presumed G-binding domain of FHOD1 is rather a spectrin repeat (SR) binding enhancer for the neighboring FH3 domain. The structure reveals that SR binding by FHOD1 is likely not regulated by the diaphanous-autoregulatory domain helix of FHOD1. Finally, we establish that Nes1G also has one FHOD1 binding SR, indicating that these abundant, giant Nesprins have overlapping functions in actin-bundle recruitment for nuclear movement.
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Affiliation(s)
- Sing Mei Lim
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Victor E Cruz
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Susumu Antoku
- Department of Pathology and Cell Biology, Columbia University, New York, NY 10032, USA
| | - Gregg G Gundersen
- Department of Pathology and Cell Biology, Columbia University, New York, NY 10032, USA
| | - Thomas U Schwartz
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
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5
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Antoku S, Wu W, Joseph LC, Morrow JP, Worman HJ, Gundersen GG. ERK1/2 Phosphorylation of FHOD Connects Signaling and Nuclear Positioning Alternations in Cardiac Laminopathy. Dev Cell 2020; 51:602-616.e12. [PMID: 31794718 DOI: 10.1016/j.devcel.2019.10.023] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2019] [Revised: 08/06/2019] [Accepted: 10/24/2019] [Indexed: 12/13/2022]
Abstract
Mutations in the lamin A/C gene (LMNA) cause cardiomyopathy and also disrupt nuclear positioning in fibroblasts. LMNA mutations causing cardiomyopathy elevate ERK1/2 activity in the heart, and inhibition of the ERK1/2 kinase activity ameliorates pathology, but the downstream effectors remain largely unknown. We now show that cardiomyocytes from mice with an Lmna mutation and elevated cardiac ERK1/2 activity have altered nuclear positioning. In fibroblasts, ERK1/2 activation negatively regulated nuclear movement by phosphorylating S498 of FHOD1. Expression of an unphosphorylatable FHOD1 variant rescued the nuclear movement defect in fibroblasts expressing a cardiomyopathy-causing lamin A mutant. In hearts of mice with LMNA mutation-induced cardiomyopathy, ERK1/2 mediated phosphorylation of FHOD3, an isoform highly expressed in cardiac tissue. Phosphorylation of FHOD1 and FHOD3 inhibited their actin bundling activity. These results show that phosphorylation of FHOD proteins by ERK1/2 is a critical switch for nuclear positioning and may play a role in the pathogenesis of cardiomyopathy caused by LMNA mutations.
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Affiliation(s)
- Susumu Antoku
- Department of Pathology and Cell Biology, Vagelos College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA
| | - Wei Wu
- Department of Pathology and Cell Biology, Vagelos College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA; Department of Medicine, Vagelos College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA
| | - Leroy C Joseph
- Department of Medicine, Vagelos College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA
| | - John P Morrow
- Department of Medicine, Vagelos College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA
| | - Howard J Worman
- Department of Pathology and Cell Biology, Vagelos College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA; Department of Medicine, Vagelos College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA
| | - Gregg G Gundersen
- Department of Pathology and Cell Biology, Vagelos College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA.
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6
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Methods to Measure Perinuclear Actin Dynamics During Nuclear Movement in Migrating Cells. Methods Mol Biol 2019; 2101:371-385. [PMID: 31879914 DOI: 10.1007/978-1-0716-0219-5_21] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/03/2023]
Abstract
The nucleus is specifically positioned within a cell in diverse biological contexts. There are multiple connections between the nuclear envelope and the cytoskeleton and these connections are involved in nuclear positioning. During cell polarization prior to cell migration, nuclear envelope proteins bind to the actin cytoskeleton and get organized into linear arrays, known as transmembrane actin-associated nuclear (TAN) lines to move the nucleus away from the leading edge. Here we describe methods to study perinuclear actin dynamics, including measurement of the thickness of actin cables coupled to TAN lines, measurement of the number of perinuclear actin cables, and ablation of perinuclear actin cables. These methods are used to identify mechanisms of nuclear positioning.
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7
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Zhu R, Gundersen GG. Centrifugal Displacement of Nuclei in Adherent Cells to Study LINC Complex-Dependent Mechanisms of Homeostatic Nuclear Positioning. Methods Mol Biol 2019; 1840:91-100. [PMID: 30141041 DOI: 10.1007/978-1-4939-8691-0_9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/09/2023]
Abstract
The positioning of the nucleus is critical for key cellular processes including division, migration, and differentiation. Traditional approaches to understanding the functions and mechanisms of nuclear positioning have relied upon cellular systems in which nuclei move in response to stimuli or developmental programs and use molecular or pharmacological perturbations of nuclear and cytoskeletal elements. Here, we describe a complimentary approach to perturbing nuclear position in adherent cells using centrifugal force and how this may be used to understand LINC complex mechanisms of homeostatic nuclear positioning.
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Affiliation(s)
- Ruijun Zhu
- Department of Pathology and Cell Biology, Columbia University, New York, NY, USA
| | - Gregg G Gundersen
- Department of Pathology and Cell Biology, Columbia University, New York, NY, USA.
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8
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Cain NE, Jahed Z, Schoenhofen A, Valdez VA, Elkin B, Hao H, Harris NJ, Herrera LA, Woolums BM, Mofrad MRK, Luxton GWG, Starr DA. Conserved SUN-KASH Interfaces Mediate LINC Complex-Dependent Nuclear Movement and Positioning. Curr Biol 2018; 28:3086-3097.e4. [PMID: 30245107 DOI: 10.1016/j.cub.2018.08.001] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2017] [Revised: 06/18/2018] [Accepted: 08/01/2018] [Indexed: 12/20/2022]
Abstract
Many nuclear positioning events involve linker of nucleoskeleton and cytoskeleton (LINC) complexes, which transmit forces generated by the cytoskeleton across the nuclear envelope. LINC complexes are formed by trans-luminal interactions between inner nuclear membrane SUN proteins and outer nuclear membrane KASH proteins, but how these interactions are regulated is poorly understood. We combine in vivo C. elegans genetics, in vitro wounded fibroblast polarization, and in silico molecular dynamics simulations to elucidate mechanisms of LINC complexes. The extension of the KASH domain by a single alanine residue or the mutation of the conserved tyrosine at -7 completely blocked the nuclear migration function of C. elegans UNC-83. Analogous mutations at -7 of mouse nesprin-2 disrupted rearward nuclear movements in NIH 3T3 cells, but did not disrupt ANC-1 in nuclear anchorage. Furthermore, conserved cysteines predicted to form a disulfide bond between SUN and KASH proteins are important for the function of certain LINC complexes, and might promote a developmental switch between nuclear migration and nuclear anchorage. Mutations of conserved cysteines in SUN or KASH disrupted ANC-1-dependent nuclear anchorage in C. elegans and Nesprin-2G-dependent nuclear movements in polarizing fibroblasts. However, the SUN cysteine mutation did not disrupt nuclear migration. Moreover, molecular dynamics simulations showed that a disulfide bond is necessary for the maximal transmission of cytoskeleton-generated forces by LINC complexes in silico. Thus, we have demonstrated functions for SUN-KASH binding interfaces, including a predicted intermolecular disulfide bond, as mechanistic determinants of nuclear positioning that may represent targets for regulation.
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Affiliation(s)
- Natalie E Cain
- Department of Molecular and Cellular Biology, University of California, Davis, 1 Shields Avenue, Davis, CA 95616, USA
| | - Zeinab Jahed
- Molecular Cell Biomechanics Laboratory, Departments of Bioengineering and Mechanical Engineering, University of California, Berkeley, 208A Stanley Hall, Berkeley, CA 94720, USA
| | - Amy Schoenhofen
- Department of Genetics, Cell Biology, and Development, University of Minnesota, 420 Washington Avenue SE, Minneapolis, MN 55455, USA
| | - Venecia A Valdez
- Department of Molecular and Cellular Biology, University of California, Davis, 1 Shields Avenue, Davis, CA 95616, USA
| | - Baila Elkin
- Department of Genetics, Cell Biology, and Development, University of Minnesota, 420 Washington Avenue SE, Minneapolis, MN 55455, USA
| | - Hongyan Hao
- Department of Molecular and Cellular Biology, University of California, Davis, 1 Shields Avenue, Davis, CA 95616, USA
| | - Nathan J Harris
- Department of Genetics, Cell Biology, and Development, University of Minnesota, 420 Washington Avenue SE, Minneapolis, MN 55455, USA
| | - Leslie A Herrera
- Department of Molecular and Cellular Biology, University of California, Davis, 1 Shields Avenue, Davis, CA 95616, USA
| | - Brian M Woolums
- Department of Genetics, Cell Biology, and Development, University of Minnesota, 420 Washington Avenue SE, Minneapolis, MN 55455, USA
| | - Mohammad R K Mofrad
- Molecular Cell Biomechanics Laboratory, Departments of Bioengineering and Mechanical Engineering, University of California, Berkeley, 208A Stanley Hall, Berkeley, CA 94720, USA
| | - G W Gant Luxton
- Department of Genetics, Cell Biology, and Development, University of Minnesota, 420 Washington Avenue SE, Minneapolis, MN 55455, USA
| | - Daniel A Starr
- Department of Molecular and Cellular Biology, University of California, Davis, 1 Shields Avenue, Davis, CA 95616, USA.
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Zhu R, Antoku S, Gundersen GG. Centrifugal Displacement of Nuclei Reveals Multiple LINC Complex Mechanisms for Homeostatic Nuclear Positioning. Curr Biol 2017; 27:3097-3110.e5. [PMID: 28988861 DOI: 10.1016/j.cub.2017.08.073] [Citation(s) in RCA: 55] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2017] [Revised: 07/26/2017] [Accepted: 08/30/2017] [Indexed: 11/18/2022]
Abstract
Nuclear movement is critical for developmental events, cell polarity, and migration and is usually mediated by linker of nucleoskeleton and cytoskeleton (LINC) complexes connecting the nucleus to cytoskeletal elements. Compared to active nuclear movement, relatively little is known about homeostatic positioning of nuclei, including whether it is an active process. To explore homeostatic nuclear positioning, we developed a method to displace nuclei in adherent cells using centrifugal force. Nuclei displaced by centrifugation rapidly recentered by mechanisms that depended on cell context. In cell monolayers with wounds oriented orthogonal to the force, nuclei were displaced toward the front and back of the cells on the two sides of the wound. Nuclei recentered from both positions, but at different rates and with different cytoskeletal linkage mechanisms. Rearward recentering was actomyosin, nesprin-2G, and SUN2 dependent, whereas forward recentering was microtubule, dynein, nesprin-2G, and SUN1 dependent. Nesprin-2G engaged actin through its N terminus and microtubules through a novel dynein interacting site near its C terminus. Both activities were necessary to maintain nuclear position in uncentrifuged cells. Thus, even when not moving, nuclei are actively maintained in position by engaging the cytoskeleton through the LINC complex.
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Affiliation(s)
- Ruijun Zhu
- Department of Pathology and Cell Biology, Columbia University, 630 West 168(th) Street, New York, NY 10032, USA
| | - Susumu Antoku
- Department of Pathology and Cell Biology, Columbia University, 630 West 168(th) Street, New York, NY 10032, USA
| | - Gregg G Gundersen
- Department of Pathology and Cell Biology, Columbia University, 630 West 168(th) Street, New York, NY 10032, USA.
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