1
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Storey EC, Holt I, Brown S, Synowsky S, Shirran S, Fuller HR. Proteomic characterization of human LMNA-related congenital muscular dystrophy muscle cells. Neuromuscul Disord 2024; 38:26-41. [PMID: 38554696 DOI: 10.1016/j.nmd.2024.03.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2024] [Revised: 03/08/2024] [Accepted: 03/11/2024] [Indexed: 04/02/2024]
Abstract
LMNA-related congenital muscular dystrophy (L-CMD) is caused by mutations in the LMNA gene, encoding lamin A/C. To further understand the molecular mechanisms of L-CMD, proteomic profiling using DIA mass spectrometry was conducted on immortalized myoblasts and myotubes from controls and L-CMD donors each harbouring a different LMNA mutation (R249W, del.32 K and L380S). Compared to controls, 124 and 228 differentially abundant proteins were detected in L-CMD myoblasts and myotubes, respectively, and were associated with enriched canonical pathways including synaptogenesis and necroptosis in myoblasts, and Huntington's disease and insulin secretion in myotubes. Abnormal nuclear morphology and reduced lamin A/C and emerin abundance was evident in all L-CMD cell lines compared to controls, while nucleoplasmic aggregation of lamin A/C was restricted to del.32 K cells, and mislocalization of emerin was restricted to R249W cells. Abnormal nuclear morphology indicates loss of nuclear lamina integrity as a common feature of L-CMD, likely rendering muscle cells vulnerable to mechanically induced stress, while differences between L-CMD cell lines in emerin and lamin A localization suggests that some molecular alterations in L-CMD are mutation specific. Nonetheless, identifying common proteomic alterations and molecular pathways across all three L-CMD lines has highlighted potential targets for the development of non-mutation specific therapies.
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Affiliation(s)
- Emily C Storey
- Wolfson Centre for Inherited Neuromuscular Disease, RJAH Orthopaedic Hospital, Oswestry, SY10 7AG, UK; The School of Pharmacy and Bioengineering, Keele University, ST5 5BG, UK
| | - Ian Holt
- Wolfson Centre for Inherited Neuromuscular Disease, RJAH Orthopaedic Hospital, Oswestry, SY10 7AG, UK; The School of Pharmacy and Bioengineering, Keele University, ST5 5BG, UK
| | - Sharon Brown
- Wolfson Centre for Inherited Neuromuscular Disease, RJAH Orthopaedic Hospital, Oswestry, SY10 7AG, UK; The School of Pharmacy and Bioengineering, Keele University, ST5 5BG, UK
| | - Silvia Synowsky
- BSRC Mass Spectrometry and Proteomics Facility, University of St Andrews, KY16 9ST, UK
| | - Sally Shirran
- BSRC Mass Spectrometry and Proteomics Facility, University of St Andrews, KY16 9ST, UK
| | - Heidi R Fuller
- Wolfson Centre for Inherited Neuromuscular Disease, RJAH Orthopaedic Hospital, Oswestry, SY10 7AG, UK; The School of Pharmacy and Bioengineering, Keele University, ST5 5BG, UK.
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2
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Kim HJ, Lee PCW, Hong JH. Overview of cellular homeostasis-associated nuclear envelope lamins and associated input signals. Front Cell Dev Biol 2023; 11:1173514. [PMID: 37250905 PMCID: PMC10213260 DOI: 10.3389/fcell.2023.1173514] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2023] [Accepted: 05/03/2023] [Indexed: 05/31/2023] Open
Abstract
With the discovery of the role of the nuclear envelope protein lamin in human genetic diseases, further diverse roles of lamins have been elucidated. The roles of lamins have been addressed in cellular homeostasis including gene regulation, cell cycle, cellular senescence, adipogenesis, bone remodeling as well as modulation of cancer biology. Features of laminopathies line with oxidative stress-associated cellular senescence, differentiation, and longevity and share with downstream of aging-oxidative stress. Thus, in this review, we highlighted various roles of lamin as key molecule of nuclear maintenance, specially lamin-A/C, and mutated LMNA gene clearly reveal aging-related genetic phenotypes, such as enhanced differentiation, adipogenesis, and osteoporosis. The modulatory roles of lamin-A/C in stem cell differentiation, skin, cardiac regulation, and oncology have also been elucidated. In addition to recent advances in laminopathies, we highlighted for the first kinase-dependent nuclear lamin biology and recently developed modulatory mechanisms or effector signals of lamin regulation. Advanced knowledge of the lamin-A/C proteins as diverse signaling modulators might be biological key to unlocking the complex signaling of aging-related human diseases and homeostasis in cellular process.
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Affiliation(s)
- Hyeong Jae Kim
- Department of Physiology, Lee Gil Ya Cancer and Diabetes Institute, Gachon University, Incheon, Republic of Korea
| | - Peter C. W. Lee
- Lung Cancer Research Center, Asan Medical Center, College of Medicine, University of Ulsan, Seoul, Republic of Korea
| | - Jeong Hee Hong
- Department of Physiology, Lee Gil Ya Cancer and Diabetes Institute, Gachon University, Incheon, Republic of Korea
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3
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Hansen E, Holaska JM. The nuclear envelope and metastasis. Oncotarget 2023; 14:317-320. [PMID: 37057891 PMCID: PMC10103595 DOI: 10.18632/oncotarget.28375] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2023] [Indexed: 04/15/2023] Open
Affiliation(s)
| | - James M. Holaska
- Correspondence to:James M. Holaska, Department of Biomedical Sciences, Cooper Medical School of Rowan University, Camden, NJ 08103, USA; Rowan University Graduate School of Biomedical Sciences, Stratford, NJ 08084, USA email
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4
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Scott NR, Parekh SH. A-type lamins involvement in transport and implications in cancer? Nucleus 2022; 13:221-235. [PMID: 36109835 PMCID: PMC9481127 DOI: 10.1080/19491034.2022.2118418] [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] [Indexed: 11/08/2022] Open
Abstract
Nuclear lamins and transport are intrinsically linked, but their relationship is yet to be fully unraveled. A multitude of complex, coupled interactions between lamins and nucleoporins (Nups), which mediate active transport into and out of the nucleus, combined with well documented dysregulation of lamins in many cancers, suggests that lamins and nuclear transport may play a pivotal role in carcinogenesis and the preservation of cancer. Changes of function related to lamin/Nup activity can principally lead to DNA damage, further increasing the genetic diversity within a tumor, which could lead to the reduction the effectiveness of antineoplastic treatments. This review discusses and synthesizes different connections of lamins to nuclear transport and offers a number of outlook questions, the answers to which could reveal a new perspective on the connection of lamins to molecular transport of cancer therapeutics, in addition to their established role in nuclear mechanics.
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Affiliation(s)
- Nicholas R. Scott
- Department of Biomedical Engineering, University of Texas at Austin, Austin, TX, USA
| | - Sapun H. Parekh
- Department of Biomedical Engineering, University of Texas at Austin, Austin, TX, USA
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5
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Stenvall CGA, Nyström JH, Butler-Hallissey C, Jansson T, Heikkilä TRH, Adam SA, Foisner R, Goldman RD, Ridge KM, Toivola DM. Cytoplasmic keratins couple with and maintain nuclear envelope integrity in colonic epithelial cells. Mol Biol Cell 2022; 33:ar121. [PMID: 36001365 PMCID: PMC9634972 DOI: 10.1091/mbc.e20-06-0387] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
Keratin intermediate filaments convey mechanical stability and protection against stress to epithelial cells. Keratins are essential for colon health, as seen in keratin 8 knockout (K8-/-) mice exhibiting a colitis phenotype. We hypothesized that keratins support the nuclear envelope and lamina in colonocytes. K8-/- colonocytes in vivo exhibit significantly decreased levels of lamins A/C, B1, and B2 in a colon-specific and cell-intrinsic manner. CRISPR/Cas9- or siRNA-mediated K8 knockdown in Caco-2 cells similarly decreased lamin levels, which recovered after reexpression of K8 following siRNA treatment. Nuclear area was not decreased, and roundness was only marginally increased in cells without K8. Down-regulation of K8 in adult K8flox/flox;Villin-CreERt2 mice following tamoxifen administration significantly decreased lamin levels at day 4 when K8 levels had reduced to 40%. K8 loss also led to reduced levels of plectin, LINC complex, and lamin-associated proteins. While keratins were not seen in the nucleoplasm without or with leptomycin B treatment, keratins were found intimately located at the nuclear envelope and complexed with SUN2 and lamin A. Furthermore, K8 loss in Caco-2 cells compromised nuclear membrane integrity basally and after shear stress. In conclusion, colonocyte K8 helps maintain nuclear envelope and lamina composition and contributes to nuclear integrity.
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Affiliation(s)
| | - Joel H. Nyström
- Cell Biology, Biosciences, Faculty of Science and Engineering, Åbo Akademi University
| | - Ciarán Butler-Hallissey
- Cell Biology, Biosciences, Faculty of Science and Engineering, Åbo Akademi University,Turku Bioscience Centre, University of Turku, and Åbo Akademi University, and,Aix Marseille Université, CNRS, INP UMR7051, NeuroCyto, 13005 Marseille, France
| | - Theresia Jansson
- Cell Biology, Biosciences, Faculty of Science and Engineering, Åbo Akademi University
| | - Taina R. H. Heikkilä
- Cell Biology, Biosciences, Faculty of Science and Engineering, Åbo Akademi University
| | | | - Roland Foisner
- Max Perutz Labs, Medical University of Vienna, Vienna Biocenter Campus, 1030 Vienna, Austria
| | | | - Karen M. Ridge
- Department of Cell and Developmental Biology and,Pulmonary and Critical Care Medicine, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611
| | - Diana M. Toivola
- Cell Biology, Biosciences, Faculty of Science and Engineering, Åbo Akademi University,InFLAMES Research Flagship Center, Åbo Akademi University, 20500 Turku, Finland,Turku Center for Disease Modeling, University of Turku, 20520 Turku, Finland,*Address correspondence to: Diana M. Toivola ()
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6
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Tang Y, Zhu L, Cho JS, Li XY, Weiss SJ. Matrix remodeling controls a nuclear lamin A/C-emerin network that directs Wnt-regulated stem cell fate. Dev Cell 2022; 57:480-495.e6. [PMID: 35150612 PMCID: PMC8891068 DOI: 10.1016/j.devcel.2022.01.015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2021] [Revised: 12/09/2021] [Accepted: 01/21/2022] [Indexed: 11/30/2022]
Abstract
Skeletal stem cells (SSCs) reside within a three-dimensional extracellular matrix (ECM) compartment and differentiate into multiple cell lineages, thereby controlling tissue maintenance and regeneration. Within this environment, SSCs can proteolytically remodel the surrounding ECM in response to growth factors that direct lineage commitment via undefined mechanisms. Here, we report that Mmp14-dependent ECM remodeling coordinates canonical Wnt signaling and guides stem cell fate by triggering an integrin-activated reorganization of the SCC cytoskeleton that controls nuclear lamin A/C levels via the linker of nucleoskeleton and cytoskeleton (LINC) complexes. In turn, SSC lamin A/C levels dictate the localization of emerin, an inner nuclear membrane protein whose ability to regulate β-catenin activity modulates Wnt signaling while directing lineage commitment in vitro and in vivo. These findings define a previously undescribed axis wherein SSCs use Mmp14-dependent ECM remodeling to control cytoskeletal and nucleoskeletal organization, thereby governing Wnt-dependent stem cell fate decisions.
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Affiliation(s)
- Yi Tang
- Division of Genetic Medicine, Department of Internal Medicine, University of Michigan, Ann Arbor, MI 48109, USA; Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109, USA.
| | - Lingxin Zhu
- Division of Genetic Medicine, Department of Internal Medicine, University of Michigan, Ann Arbor, MI 48109,Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109
| | - Jung-Sun Cho
- Division of Genetic Medicine, Department of Internal Medicine, University of Michigan, Ann Arbor, MI 48109,Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109
| | - Xiao-Yan Li
- Division of Genetic Medicine, Department of Internal Medicine, University of Michigan, Ann Arbor, MI 48109,Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109
| | - Stephen J. Weiss
- Division of Genetic Medicine, Department of Internal Medicine, University of Michigan, Ann Arbor, MI 48109,Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109,Corresponding Authors: Stephen J. Weiss, MD, , Life Sciences Institute, Mary Sue Coleman Hall, University of Michigan, 210 Washtenaw, Ann Arbor, MI 48109-2216, Yi Tang, PhD, , Life Sciences Institute, Mary Sue Coleman Hall, University of Michigan, 210 Washtenaw, Ann Arbor, MI 48109-2216
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7
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Abstract
Lamins interact with a host of nuclear membrane proteins, transcription factors, chromatin regulators, signaling molecules, splicing factors, and even chromatin itself to form a nuclear subcompartment, the nuclear lamina, that is involved in a variety of cellular processes such as the governance of nuclear integrity, nuclear positioning, mitosis, DNA repair, DNA replication, splicing, signaling, mechanotransduction and -sensation, transcriptional regulation, and genome organization. Lamins are the primary scaffold for this nuclear subcompartment, but interactions with lamin-associated peptides in the inner nuclear membrane are self-reinforcing and mutually required. Lamins also interact, directly and indirectly, with peripheral heterochromatin domains called lamina-associated domains (LADs) and help to regulate dynamic 3D genome organization and expression of developmentally regulated genes.
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Affiliation(s)
- Xianrong Wong
- Laboratory of Developmental and Regenerative Biology, Skin Research Institute of Singapore, Agency for Science, Technology and Research (A∗STAR), Singapore 138648
| | - Ashley J Melendez-Perez
- Department of Biological Chemistry and Center for Epigenetics, Johns Hopkins University of Medicine, Baltimore, Maryland 21205, USA
| | - Karen L Reddy
- Department of Biological Chemistry and Center for Epigenetics, Johns Hopkins University of Medicine, Baltimore, Maryland 21205, USA
- Sidney Kimmel Cancer Institute, Johns Hopkins University School of Medicine, Baltimore, Maryland 21231, USA
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8
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Pothapragada SP, Gupta P, Mukherjee S, Das T. Matrix mechanics regulates epithelial defence against cancer by tuning dynamic localization of filamin. Nat Commun 2022; 13:218. [PMID: 35017535 PMCID: PMC8752856 DOI: 10.1038/s41467-021-27896-z] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2020] [Accepted: 12/17/2021] [Indexed: 12/29/2022] Open
Abstract
In epithelia, normal cells recognize and extrude out newly emerged transformed cells by competition. This process is the most fundamental epithelial defence against cancer, whose occasional failure promotes oncogenesis. However, little is known about what factors determine the success or failure of this defence. Here we report that mechanical stiffening of extracellular matrix attenuates the epithelial defence against HRasV12-transformed cells. Using photoconversion labelling, protein tracking, and loss-of-function mutations, we attribute this attenuation to stiffening-induced perinuclear sequestration of a cytoskeletal protein, filamin. On soft matrix mimicking healthy epithelium, filamin exists as a dynamically single population, which moves to the normal cell-transformed cell interface to initiate the extrusion of transformed cells. However, on stiff matrix mimicking fibrotic epithelium, filamin redistributes into two dynamically distinct populations, including a new perinuclear pool that cannot move to the cell-cell interface. A matrix stiffness-dependent differential between filamin-Cdc42 and filamin-perinuclear cytoskeleton interaction controls this distinctive filamin localization and hence, determines the success or failure of epithelial defence on soft versus stiff matrix. Together, our study reveals how pathological matrix stiffening leads to a failed epithelial defence at the initial stage of oncogenesis. Epithelial cells have the ability to competitively remove potentially cancerous cells from the tissue. Here the authors discover that pathological stiffening of extracellular matrix leads to the loss of this basic epithelial defence against cancer.
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Affiliation(s)
- Shilpa P Pothapragada
- TIFR Centre for Interdisciplinary Sciences, Tata Institute of Fundamental Research Hyderabad (TIFR-H), Hyderabad, 500 046, India
| | - Praver Gupta
- TIFR Centre for Interdisciplinary Sciences, Tata Institute of Fundamental Research Hyderabad (TIFR-H), Hyderabad, 500 046, India
| | - Soumi Mukherjee
- TIFR Centre for Interdisciplinary Sciences, Tata Institute of Fundamental Research Hyderabad (TIFR-H), Hyderabad, 500 046, India.,Department of Biology, Purdue University, West Lafayette, IN, 47907, USA
| | - Tamal Das
- TIFR Centre for Interdisciplinary Sciences, Tata Institute of Fundamental Research Hyderabad (TIFR-H), Hyderabad, 500 046, India.
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9
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Wong X, Hoskins VE, Melendez-Perez AJ, Harr JC, Gordon M, Reddy KL. Lamin C is required to establish genome organization after mitosis. Genome Biol 2021; 22:305. [PMID: 34775987 PMCID: PMC8591896 DOI: 10.1186/s13059-021-02516-7] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2020] [Accepted: 10/08/2021] [Indexed: 01/11/2023] Open
Abstract
BACKGROUND The dynamic 3D organization of the genome is central to gene regulation and development. The nuclear lamina influences genome organization through the tethering of lamina-associated domains (LADs) to the nuclear periphery. Evidence suggests that lamins A and C are the predominant lamins involved in the peripheral association of LADs, potentially serving different roles. RESULTS Here, we examine chromosome architecture in mouse cells in which lamin A or lamin C are downregulated. We find that lamin C, and not lamin A, is required for the 3D organization of LADs and overall chromosome organization. Striking differences in localization are present as cells exit mitosis and persist through early G1 and are linked to differential phosphorylation. Whereas lamin A associates with the nascent nuclear envelope (NE) during telophase, lamin C remains in the interior, surrounding globular LAD aggregates enriched on euchromatic regions. Lamin C association with the NE is delayed until several hours into G1 and correlates temporally and spatially with the post-mitotic NE association of LADs. Post-mitotic LAD association with the NE, and global 3D genome organization, is perturbed only in cells depleted of lamin C, and not lamin A. CONCLUSIONS Lamin C regulates LAD dynamics during exit from mitosis and is a key regulator of genome organization in mammalian cells. This reveals an unexpectedly central role for lamin C in genome organization, including inter-chromosomal LAD-LAD segregation and LAD scaffolding at the NE, raising intriguing questions about the individual and overlapping roles of lamin A/C in cellular function and disease.
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Affiliation(s)
- Xianrong Wong
- Department of Biological Chemistry, Center for Epigenetics, School of Medicine, Johns Hopkins University, Baltimore, MD, 21205, USA.,Current Address: Laboratory of Developmental and Regenerative Biology, A*STAR Skin Research Labs, Agency for Science, Technology and Research (A*STAR), Immunos, Singapore, 138648, Singapore
| | - Victoria E Hoskins
- Department of Biological Chemistry, Center for Epigenetics, School of Medicine, Johns Hopkins University, Baltimore, MD, 21205, USA.,McKusick-Nathans Department of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA
| | - Ashley J Melendez-Perez
- Department of Biological Chemistry, Center for Epigenetics, School of Medicine, Johns Hopkins University, Baltimore, MD, 21205, USA
| | - Jennifer C Harr
- Department of Biological Chemistry, Center for Epigenetics, School of Medicine, Johns Hopkins University, Baltimore, MD, 21205, USA.,Department of Biological Sciences, St. Mary's University, San Antonio, TX, 78228, USA
| | - Molly Gordon
- Department of Biological Chemistry, Center for Epigenetics, School of Medicine, Johns Hopkins University, Baltimore, MD, 21205, USA.,Department of Cell Biology, Center for Cell Dynamics, School of Medicine, Johns Hopkins University, Baltimore, MD, 21205, USA
| | - Karen L Reddy
- Department of Biological Chemistry, Center for Epigenetics, School of Medicine, Johns Hopkins University, Baltimore, MD, 21205, USA. .,Sidney Kimmel Comprehensive Cancer Center, School of Medicine, Johns Hopkins University, Baltimore, MD, 21205, USA.
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10
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Expression of the Ebola Virus VP24 Protein Compromises the Integrity of the Nuclear Envelope and Induces a Laminopathy-Like Cellular Phenotype. mBio 2021; 12:e0097221. [PMID: 34225493 PMCID: PMC8406168 DOI: 10.1128/mbio.00972-21] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Ebola virus (EBOV) VP24 protein is a nucleocapsid-associated protein that inhibits interferon (IFN) gene expression and counteracts the IFN-mediated antiviral response, preventing nuclear import of signal transducer and activator of transcription 1 (STAT1). Proteomic studies to identify additional EBOV VP24 partners have pointed to the nuclear membrane component emerin as a potential element of the VP24 cellular interactome. Here, we have further studied this interaction and its impact on cell biology. We demonstrate that VP24 interacts with emerin but also with other components of the inner nuclear membrane, such as lamin A/C and lamin B. We also show that VP24 diminishes the interaction between emerin and lamin A/C and compromises the integrity of the nuclear membrane. This disruption is associated with nuclear morphological abnormalities, activation of a DNA damage response, the phosphorylation of extracellular signal-regulated kinase (ERK), and the induction of interferon-stimulated gene 15 (ISG15). Interestingly, expression of VP24 also promoted the cytoplasmic translocation and downmodulation of barrier-to-autointegration factor (BAF), a common interactor of lamin A/C and emerin, leading to repression of the BAF-regulated CSF1 gene. Importantly, we found that EBOV infection results in the activation of pathways associated with nuclear envelope damage, consistent with our observations in cells expressing VP24. In summary, here we demonstrate that VP24 acts at the nuclear membrane, causing morphological and functional changes in cells that recapitulate several of the hallmarks of laminopathy diseases.
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11
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Abstract
The cell nucleus is best known as the container of the genome. Its envelope provides a barrier for passive macromolecule diffusion, which enhances the control of gene expression. As its largest and stiffest organelle, the nucleus also defines the minimal space requirements of a cell. Internal or external pressures that deform a cell to its physical limits cause a corresponding nuclear deformation. Evidence is consolidating that the nucleus, in addition to its genetic functions, serves as a physical sensing device for critical cell body deformation. Nuclear mechanotransduction allows cells to adapt their acute behaviors, mechanical stability, paracrine signaling, and fate to their physical surroundings. This review summarizes the basic chemical and mechanical properties of nuclear components, and how these properties are thought to be utilized for mechanosensing. Expected final online publication date for the Annual Review of Cell and Developmental Biology, Volume 37 is October 2021. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.
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Affiliation(s)
- Philipp Niethammer
- Cell Biology Program, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA;
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12
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Chen NY, Kim PH, Tu Y, Yang Y, Heizer PJ, Young SG, Fong LG. Increased expression of LAP2β eliminates nuclear membrane ruptures in nuclear lamin-deficient neurons and fibroblasts. Proc Natl Acad Sci U S A 2021; 118:e2107770118. [PMID: 34161290 PMCID: PMC8237679 DOI: 10.1073/pnas.2107770118] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Defects or deficiencies in nuclear lamins cause pathology in many cell types, and recent studies have implicated nuclear membrane (NM) ruptures as a cause of cell toxicity. We previously observed NM ruptures and progressive cell death in the developing brain of lamin B1-deficient mouse embryos. We also observed frequent NM ruptures and DNA damage in nuclear lamin-deficient fibroblasts. Factors modulating susceptibility to NM ruptures remain unclear, but we noted low levels of LAP2β, a chromatin-binding inner NM protein, in fibroblasts with NM ruptures. Here, we explored the apparent link between LAP2β and NM ruptures in nuclear lamin-deficient neurons and fibroblasts, and we tested whether manipulating LAP2β expression levels would alter NM rupture frequency. In cortical plate neurons of lamin B1-deficient embryos, we observed a strong correlation between low LAP2β levels and NM ruptures. We also found low LAP2β levels and frequent NM ruptures in neurons of cultured Lmnb1-/- neurospheres. Reducing LAP2β expression in Lmnb1-/- neurons with an siRNA markedly increased the NM rupture frequency (without affecting NM rupture duration), whereas increased LAP2β expression eliminated NM ruptures and reduced DNA damage. Consistent findings were observed in nuclear lamin-deficient fibroblasts. Reduced LAP2β expression increased NM ruptures, whereas increased LAP2β expression virtually abolished NM ruptures. Increased LAP2β expression nearly abolished NM ruptures in cells subjected to mechanical stress (an intervention that increases NM ruptures). Our studies showed that increasing LAP2β expression bolsters NM integrity in nuclear lamin-deficient cells and markedly reduces NM rupture frequency.
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Affiliation(s)
- Natalie Y Chen
- Department of Medicine, University of California, Los Angeles, CA 90095
| | - Paul H Kim
- Department of Medicine, University of California, Los Angeles, CA 90095
| | - Yiping Tu
- Department of Medicine, University of California, Los Angeles, CA 90095
| | - Ye Yang
- Department of Medicine, University of California, Los Angeles, CA 90095
| | - Patrick J Heizer
- Department of Medicine, University of California, Los Angeles, CA 90095
| | - Stephen G Young
- Department of Medicine, University of California, Los Angeles, CA 90095;
- Department of Human Genetics, University of California, Los Angeles, CA 90095
- Molecular Biology Institute, University of California, Los Angeles, CA 90095
| | - Loren G Fong
- Department of Medicine, University of California, Los Angeles, CA 90095;
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13
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Chiu M, Trigg B, Taracena M, Wells M. Diverse cellular morphologies during lumen maturation in Anopheles gambiae larval salivary glands. INSECT MOLECULAR BIOLOGY 2021; 30:210-230. [PMID: 33305876 PMCID: PMC8142555 DOI: 10.1111/imb.12689] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/28/2020] [Revised: 10/29/2020] [Accepted: 12/07/2020] [Indexed: 06/12/2023]
Abstract
Mosquitoes are the greatest animal threat to human health, causing hundreds of millions of infections and around 1 million deaths each year. All mosquito-borne pathogens must traverse the salivary glands (SGs) to be transmitted to the next host, making this organ an ideal target for interventions. The adult SG develops from precursor cells located in the larval SG duct bud. Characterization of the larval SG has been limited. We sought to better understand larval SG architecture, secretion and gene expression. We developed an optimized method for larval SG staining and surveyed hundreds of larval stage 4 (L4) SGs using fluorescence confocal microscopy. Remarkable variation in SG cell and chromatin organization differed among individuals and across the L4 stage. Lumen formation occurred during L4 stage through secretion likely involving a coincident cellular apical lipid enrichment and extracellular vesicle-like structures. Meta-analysis of microarray data showed that larval SG gene expression is divergent from adult SGs, more similar to larval gastric cecae, but different from other larval gut compartments. This work highlights the variable cell architecture of larval Anopheles gambiae SGs and provides candidate targets for genetic strategies aiming to disrupt SGs and transmission of mosquito-borne pathogens.
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Affiliation(s)
- M Chiu
- Department of Cell Biology, The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
- The Johns Hopkins Malaria Research Institute, The Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, USA
| | - B Trigg
- Department of Cell Biology, The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
- The Johns Hopkins Malaria Research Institute, The Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, USA
| | - M Taracena
- Centers for Disease Control and Prevention (CDC), Atlanta, Georgia, USA
| | - M Wells
- Department of Cell Biology, The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
- The Johns Hopkins Malaria Research Institute, The Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, USA
- Department of Biomedical Sciences, Idaho College of Osteopathic Medicine (ICOM), Meridian, Idaho, USA
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14
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Yamamoto-Hino M, Kawaguchi K, Ono M, Furukawa K, Goto S. Lamin is essential for nuclear localization of the GPI synthesis enzyme PIG-B and GPI-anchored protein production in Drosophila. J Cell Sci 2020; 133:jcs.238527. [PMID: 32051283 PMCID: PMC7104860 DOI: 10.1242/jcs.238527] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2019] [Accepted: 01/28/2020] [Indexed: 01/13/2023] Open
Abstract
Membrane lipid biosynthesis is a complex process that occurs in various intracellular compartments. In Drosophila, phosphatidylinositol glycan-B (PIG-B), which catalyzes addition of the third mannose in glycosylphosphatidylinositol (GPI), localizes to the nuclear envelope (NE). Although this NE localization is essential for Drosophila development, the underlying molecular mechanism remains unknown. To elucidate this mechanism, we identified PIG-B-interacting proteins by performing immunoprecipitation followed by proteomic analysis. We then examined which of these proteins are required for the NE localization of PIG-B. Knockdown of Lamin Dm0, a B-type lamin, led to mislocalization of PIG-B from the NE to the endoplasmic reticulum. Lamin Dm0 associated with PIG-B at the inner nuclear membrane, a process that required the tail domain of Lamin Dm0. Furthermore, GPI moieties were distributed abnormally in the Lamin Dm0 mutant. These data indicate that Lamin Dm0 is involved in the NE localization of PIG-B and is required for proper GPI-anchor modification of proteins. Highlighted Article: Lamin plays a role in post-translational modification of plasma membrane proteins by tethering the GPI modification enzyme PIG-B to the inner nuclear membrane.
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Affiliation(s)
- Miki Yamamoto-Hino
- Department of Life Science, College of Science, Rikkyo University, Toshima-ku, Tokyo 171-8501, Japan
| | - Kohei Kawaguchi
- Department of Life Science, College of Science, Rikkyo University, Toshima-ku, Tokyo 171-8501, Japan
| | - Masaya Ono
- Department of Clinical Proteomics, National Cancer Center Hospital, Chu-o-ku, Tokyo 104-0045, Japan
| | - Kazuhiro Furukawa
- Department of Chemistry, Faculty of Science, Niigata University, Niigata 950-2181, Japan
| | - Satoshi Goto
- Department of Life Science, College of Science, Rikkyo University, Toshima-ku, Tokyo 171-8501, Japan
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15
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Pradhan R, Nallappa MJ, Sengupta K. Lamin A/C modulates spatial organization and function of the Hsp70 gene locus via nuclear myosin I. J Cell Sci 2020; 133:jcs236265. [PMID: 31988151 DOI: 10.1242/jcs.236265] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2019] [Accepted: 01/13/2020] [Indexed: 02/06/2023] Open
Abstract
The structure-function relationship of the nucleus is tightly regulated, especially during heat shock. Typically, heat shock activates molecular chaperones that prevent protein misfolding and preserve genome integrity. However, the molecular mechanisms that regulate nuclear structure-function relationships during heat shock remain unclear. Here, we show that lamin A and C (hereafter lamin A/C; both lamin A and C are encoded by LMNA) are required for heat-shock-mediated transcriptional induction of the Hsp70 gene locus (HSPA genes). Interestingly, lamin A/C regulates redistribution of nuclear myosin I (NM1) into the nucleus upon heat shock, and depletion of either lamin A/C or NM1 abrogates heat-shock-induced repositioning of Hsp70 gene locus away from the nuclear envelope. Lamins and NM1 also regulate spatial positioning of the SC35 (also known as SRSF2) speckles - important nuclear landmarks that modulates Hsp70 gene locus expression upon heat shock. This suggests an intricate crosstalk between nuclear lamins, NM1 and SC35 organization in modulating transcriptional responses of the Hsp70 gene locus during heat shock. Taken together, this study unravels a novel role for lamin A/C in the regulation of the spatial dynamics and function of the Hsp70 gene locus upon heat shock, via the nuclear motor protein NM1.This article has an associated First Person interview with the first author of the paper.
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Affiliation(s)
- Roopali Pradhan
- Biology, Main Building, First Floor, Room B-216, Indian Institute of Science Education and Research (IISER), Pune 411008, India
| | - Muhunden Jayakrishnan Nallappa
- Biology, Main Building, First Floor, Room B-216, Indian Institute of Science Education and Research (IISER), Pune 411008, India
| | - Kundan Sengupta
- Biology, Main Building, First Floor, Room B-216, Indian Institute of Science Education and Research (IISER), Pune 411008, India
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16
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Buchwalter A, Schulte R, Tsai H, Capitanio J, Hetzer M. Selective clearance of the inner nuclear membrane protein emerin by vesicular transport during ER stress. eLife 2019; 8:e49796. [PMID: 31599721 PMCID: PMC6802967 DOI: 10.7554/elife.49796] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2019] [Accepted: 10/09/2019] [Indexed: 12/17/2022] Open
Abstract
The inner nuclear membrane (INM) is a subdomain of the endoplasmic reticulum (ER) that is gated by the nuclear pore complex. It is unknown whether proteins of the INM and ER are degraded through shared or distinct pathways in mammalian cells. We applied dynamic proteomics to profile protein half-lives and report that INM and ER residents turn over at similar rates, indicating that the INM's unique topology is not a barrier to turnover. Using a microscopy approach, we observed that the proteasome can degrade INM proteins in situ. However, we also uncovered evidence for selective, vesicular transport-mediated turnover of a single INM protein, emerin, that is potentiated by ER stress. Emerin is rapidly cleared from the INM by a mechanism that requires emerin's LEM domain to mediate vesicular trafficking to lysosomes. This work demonstrates that the INM can be dynamically remodeled in response to environmental inputs.
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Affiliation(s)
- Abigail Buchwalter
- Cardiovascular Research InstituteUniversity of California, San FranciscoSan FranciscoUnited States
- Department of PhysiologyUniversity of California, San FranciscoSan FranciscoUnited States
- Chan Zuckerberg BiohubSan FranciscoUnited States
| | - Roberta Schulte
- The Salk Institute for Biological StudiesLa JollaUnited States
| | - Hsiao Tsai
- The Salk Institute for Biological StudiesLa JollaUnited States
| | | | - Martin Hetzer
- The Salk Institute for Biological StudiesLa JollaUnited States
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17
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Bianchi A, Manti PG, Lucini F, Lanzuolo C. Mechanotransduction, nuclear architecture and epigenetics in Emery Dreifuss Muscular Dystrophy: tous pour un, un pour tous. Nucleus 2019; 9:276-290. [PMID: 29619865 PMCID: PMC5973142 DOI: 10.1080/19491034.2018.1460044] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
The alteration of the several roles that Lamin A/C plays in the mammalian cell leads to a broad spectrum of pathologies that – all together – are named laminopathies. Among those, the Emery Dreifuss Muscular Dystrophy (EDMD) is of particular interest as, despite the several known mutations of Lamin A/C, the genotype–phenotype correlation still remains poorly understood; this suggests that the epigenetic background of patients might play an important role during the time course of the disease. Historically, both a mechanical role of Lamin A/C and a regulative one have been suggested as the driving force of laminopathies; however, those two hypotheses are not mutually exclusive. Recent scientific evidence shows that Lamin A/C sustains the correct gene expression at the epigenetic level thanks to the Lamina Associated Domains (LADs) reorganization and the crosstalk with the Polycomb Group of Proteins (PcG). Furthermore, the PcG-dependent histone mark H3K27me3 increases under mechanical stress, finally pointing out the link between the mechano-properties of the nuclear lamina and epigenetics. Here, we summarize the emerging mechanisms that could explain the high variability seen in Emery Dreifuss muscular dystrophy.
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Affiliation(s)
- Andrea Bianchi
- a CNR Institute of Cell Biology and Neurobiology, Istituto di Ricovero e Cura a Carattere Scientifico Fondazione Santa Lucia , Rome , Italy.,b Istituto Nazionale Genetica Molecolare Romeo ed Enrica Invernizzi , Milan , Italy
| | | | - Federica Lucini
- b Istituto Nazionale Genetica Molecolare Romeo ed Enrica Invernizzi , Milan , Italy
| | - Chiara Lanzuolo
- a CNR Institute of Cell Biology and Neurobiology, Istituto di Ricovero e Cura a Carattere Scientifico Fondazione Santa Lucia , Rome , Italy.,b Istituto Nazionale Genetica Molecolare Romeo ed Enrica Invernizzi , Milan , Italy.,c Istituto di Ricovero e Cura a Carattere Scientifico Fondazione Santa Lucia , Rome , Italy
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18
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Abstract
Cellular nuclei are bound by two uniformly separated lipid membranes that are fused with each other at numerous donut-shaped pores. These membranes are structurally supported by an array of distinct proteins with distinct mechanical functions. As a result, the nuclear envelope possesses unique mechanical properties, which enables it to resist cytoskeletal forces. Here, we review studies that are beginning to provide quantitative insights into nuclear membrane mechanics. We discuss how the mechanical properties of the fused nuclear membranes mediate their response to mechanical forces exerted on the nucleus and how structural reinforcement by different nuclear proteins protects the nuclear membranes against rupture. We also highlight some open questions in nuclear envelope mechanics, and discuss their relevance in the context of health and disease.
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Affiliation(s)
- Ashutosh Agrawal
- Department of Mechanical Engineering, University of Houston, Houston, TX 77204, USA
| | - Tanmay P Lele
- Department of Chemical Engineering, University of Florida, Gainesville, FL 32611, USA
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19
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Samson C, Petitalot A, Celli F, Herrada I, Ropars V, Le Du MH, Nhiri N, Jacquet E, Arteni AA, Buendia B, Zinn-Justin S. Structural analysis of the ternary complex between lamin A/C, BAF and emerin identifies an interface disrupted in autosomal recessive progeroid diseases. Nucleic Acids Res 2019; 46:10460-10473. [PMID: 30137533 PMCID: PMC6212729 DOI: 10.1093/nar/gky736] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2017] [Accepted: 08/02/2018] [Indexed: 01/22/2023] Open
Abstract
Lamins are the main components of the nucleoskeleton. Whereas their 3D organization was recently described using cryoelectron tomography, no structural data highlights how they interact with their partners at the interface between the inner nuclear envelope and chromatin. A large number of mutations causing rare genetic disorders called laminopathies were identified in the C-terminal globular Igfold domain of lamins A and C. We here present a first structural description of the interaction between the lamin A/C immunoglobulin-like domain and emerin, a nuclear envelope protein. We reveal that this lamin A/C domain both directly binds self-assembled emerin and interacts with monomeric emerin LEM domain through the dimeric chromatin-associated Barrier-to-Autointegration Factor (BAF) protein. Mutations causing autosomal recessive progeroid syndromes specifically impair proper binding of lamin A/C domain to BAF, thus destabilizing the link between lamin A/C and BAF in cells. Recent data revealed that, during nuclear assembly, BAF’s ability to bridge distant DNA sites is essential for guiding membranes to form a single nucleus around the mitotic chromosome ensemble. Our results suggest that BAF interaction with lamin A/C also plays an essential role, and that mutations associated with progeroid syndromes leads to a dysregulation of BAF-mediated chromatin organization and gene expression.
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Affiliation(s)
- Camille Samson
- Institut de Biologie Intégrative de la Cellule (I2BC), CEA, CNRS, Université Paris Sud, Université Paris-Saclay, Gif-sur-Yvette, France
| | - Ambre Petitalot
- Institut de Biologie Intégrative de la Cellule (I2BC), CEA, CNRS, Université Paris Sud, Université Paris-Saclay, Gif-sur-Yvette, France
| | - Florian Celli
- Institut de Biologie Intégrative de la Cellule (I2BC), CEA, CNRS, Université Paris Sud, Université Paris-Saclay, Gif-sur-Yvette, France
| | - Isaline Herrada
- Institut de Biologie Intégrative de la Cellule (I2BC), CEA, CNRS, Université Paris Sud, Université Paris-Saclay, Gif-sur-Yvette, France
| | - Virginie Ropars
- Institut de Biologie Intégrative de la Cellule (I2BC), CEA, CNRS, Université Paris Sud, Université Paris-Saclay, Gif-sur-Yvette, France
| | - Marie-Hélène Le Du
- Institut de Biologie Intégrative de la Cellule (I2BC), CEA, CNRS, Université Paris Sud, Université Paris-Saclay, Gif-sur-Yvette, France
| | - Naïma Nhiri
- Institut de Chimie des Substances Naturelles, Université Paris Sud, Université Paris-Saclay, CNRS UPR 2301, Gif-sur-Yvette, France
| | - Eric Jacquet
- Institut de Chimie des Substances Naturelles, Université Paris Sud, Université Paris-Saclay, CNRS UPR 2301, Gif-sur-Yvette, France
| | - Ana-Andrea Arteni
- Institut de Biologie Intégrative de la Cellule (I2BC), CEA, CNRS, Université Paris Sud, Université Paris-Saclay, Gif-sur-Yvette, France
| | - Brigitte Buendia
- Unité de Biologie Fonctionnelle et Adaptative (BFA), CNRS UMR 8251, Université Paris Diderot, Sorbonne Paris Cité, Paris, France
| | - Sophie Zinn-Justin
- Institut de Biologie Intégrative de la Cellule (I2BC), CEA, CNRS, Université Paris Sud, Université Paris-Saclay, Gif-sur-Yvette, France
- To whom correspondence should be addressed. Tel: +33 169083026;
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20
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Sidorenko E, Vartiainen MK. Nucleoskeletal regulation of transcription: Actin on MRTF. Exp Biol Med (Maywood) 2019; 244:1372-1381. [PMID: 31142145 DOI: 10.1177/1535370219854669] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
Myocardin-related transcription factor A (MRTF-A) and serum response factor (SRF) form an essential transcriptional complex that regulates the expression of many cytoskeletal genes in response to dynamic changes in the actin cytoskeleton. The nucleoskeleton, a “dynamic network of networks,” consists of numerous proteins that contribute to nuclear shape and to its various functions, including gene expression. In this review, we will discuss recent work that has identified many nucleoskeletal proteins, such as nuclear lamina and lamina-associated proteins, nuclear actin, and the linker of the cytoskeleton and nucleoskeleton complex as important regulators of MRTF-A/SRF transcriptional activity, especially in the context of mechanical control of transcription. Impact statement Regulation of gene expression is a fundamental cellular process that ensures the appropriate response of a cell to its surroundings. Alongside biochemical signals, mechanical cues, such as substrate rigidity, have been recognized as key regulators of gene expression. Nucleoskeletal components play an important role in mechanoresponsive transcription, particularly in controlling the activity of MRTF-A/SRF transcription factors. This ensures that the cell can balance the internal and external mechanical forces by fine-tuning the expression of cytoskeletal genes.
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Affiliation(s)
- Ekaterina Sidorenko
- Institute of Biotechnology, Helsinki Institute of Life Science, University of Helsinki, Helsinki 00014, Finland
| | - Maria K Vartiainen
- Institute of Biotechnology, Helsinki Institute of Life Science, University of Helsinki, Helsinki 00014, Finland
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21
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Sola-Carvajal A, Revêchon G, Helgadottir HT, Whisenant D, Hagblom R, Döhla J, Katajisto P, Brodin D, Fagerström-Billai F, Viceconte N, Eriksson M. Accumulation of Progerin Affects the Symmetry of Cell Division and Is Associated with Impaired Wnt Signaling and the Mislocalization of Nuclear Envelope Proteins. J Invest Dermatol 2019; 139:2272-2280.e12. [PMID: 31128203 DOI: 10.1016/j.jid.2019.05.005] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2018] [Revised: 05/02/2019] [Accepted: 05/08/2019] [Indexed: 12/17/2022]
Abstract
Hutchinson-Gilford progeria syndrome (HGPS) is the result of a defective form of the lamin A protein called progerin. While progerin is known to disrupt the properties of the nuclear lamina, the underlying mechanisms responsible for the pathophysiology of HGPS remain less clear. Previous studies in our laboratory have shown that progerin expression in murine epidermal basal cells results in impaired stratification and halted development of the skin. Stratification and differentiation of the epidermis is regulated by asymmetric stem cell division. Here, we show that expression of progerin impairs the ability of stem cells to maintain tissue homeostasis as a result of altered cell division. Quantification of basal skin cells showed an increase in symmetric cell division that correlated with progerin accumulation in HGPS mice. Investigation of the mechanisms underlying this phenomenon revealed a putative role of Wnt/β-catenin signaling. Further analysis suggested an alteration in the nuclear translocation of β-catenin involving the inner and outer nuclear membrane proteins, emerin and nesprin-2. Taken together, our results suggest a direct involvement of progerin in the transmission of Wnt signaling and normal stem cell division. These insights into the molecular mechanisms of progerin may help develop new treatment strategies for HGPS.
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Affiliation(s)
- Agustín Sola-Carvajal
- Department of Biosciences and Nutrition, Center for Innovative Medicine, Karolinska Institutet, Huddinge, Sweden.
| | - Gwladys Revêchon
- Department of Biosciences and Nutrition, Center for Innovative Medicine, Karolinska Institutet, Huddinge, Sweden
| | - Hafdis T Helgadottir
- Department of Biosciences and Nutrition, Center for Innovative Medicine, Karolinska Institutet, Huddinge, Sweden
| | - Daniel Whisenant
- Department of Biosciences and Nutrition, Center for Innovative Medicine, Karolinska Institutet, Huddinge, Sweden
| | - Robin Hagblom
- Department of Biosciences and Nutrition, Center for Innovative Medicine, Karolinska Institutet, Huddinge, Sweden
| | - Julia Döhla
- Department of Biosciences and Nutrition, Center for Innovative Medicine, Karolinska Institutet, Huddinge, Sweden; Institute of Biotechnology, University of Helsinki, Helsinki, Finland
| | - Pekka Katajisto
- Department of Biosciences and Nutrition, Center for Innovative Medicine, Karolinska Institutet, Huddinge, Sweden; Institute of Biotechnology, University of Helsinki, Helsinki, Finland
| | - David Brodin
- Bioinformatics and Expression Core Facility, Karolinska Institutet, Huddinge, Sweden
| | | | - Nikenza Viceconte
- Department of Biosciences and Nutrition, Center for Innovative Medicine, Karolinska Institutet, Huddinge, Sweden
| | - Maria Eriksson
- Department of Biosciences and Nutrition, Center for Innovative Medicine, Karolinska Institutet, Huddinge, Sweden.
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22
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Ranade D, Pradhan R, Jayakrishnan M, Hegde S, Sengupta K. Lamin A/C and Emerin depletion impacts chromatin organization and dynamics in the interphase nucleus. BMC Mol Cell Biol 2019; 20:11. [PMID: 31117946 PMCID: PMC6532135 DOI: 10.1186/s12860-019-0192-5] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2019] [Accepted: 04/16/2019] [Indexed: 12/26/2022] Open
Abstract
Background Nuclear lamins are type V intermediate filament proteins that maintain nuclear structure and function. Furthermore, Emerin - an interactor of Lamin A/C, facilitates crosstalk between the cytoskeleton and the nucleus as it also interacts with actin and Nuclear Myosin 1 (NM1). Results Here we show that the depletion of Lamin A/C or Emerin, alters the localization of the nuclear motor protein - Nuclear Myosin 1 (NM1) that manifests as an increase in NM1 foci in the nucleus and are rescued to basal levels upon the combined knockdown of Lamin A/C and Emerin. Furthermore, Lamin A/C-Emerin co-depletion destabilizes cytoskeletal organization as it increases actin stress fibers. This further impinges on nuclear organization, as it enhances chromatin mobility more toward the nuclear interior in Lamin A/C-Emerin co-depleted cells. This enhanced chromatin mobility was restored to basal levels either upon inhibition of Nuclear Myosin 1 (NM1) activity or actin depolymerization. In addition, the combined loss of Lamin A/C and Emerin alters the otherwise highly conserved spatial positions of chromosome territories. Furthermore, knockdown of Lamin A/C or Lamin A/C-Emerin combined, deregulates expression levels of a candidate subset of genes. Amongst these genes, both KLK10 (Chr.19, Lamina Associated Domain (LAD+)) and MADH2 (Chr.18, LAD-) were significantly repressed, while BCL2L12 (Chr.19, LAD-) is de-repressed. These genes differentially reposition with respect to the nuclear envelope. Conclusions Taken together, these studies underscore a remarkable interplay between Lamin A/C and Emerin in modulating cytoskeletal organization of actin and NM1 that impinges on chromatin dynamics and function in the interphase nucleus. Electronic supplementary material The online version of this article (10.1186/s12860-019-0192-5) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Devika Ranade
- Indian Institute of Science Education and Research (IISER)-Pune, Dr. Homi Bhabha Road, Biology, Room#B-216, 1st Floor, Main Building, Pashan, Pune, Maharashtra, 411008, India
| | - Roopali Pradhan
- Indian Institute of Science Education and Research (IISER)-Pune, Dr. Homi Bhabha Road, Biology, Room#B-216, 1st Floor, Main Building, Pashan, Pune, Maharashtra, 411008, India
| | - Muhunden Jayakrishnan
- Indian Institute of Science Education and Research (IISER)-Pune, Dr. Homi Bhabha Road, Biology, Room#B-216, 1st Floor, Main Building, Pashan, Pune, Maharashtra, 411008, India
| | - Sushmitha Hegde
- Indian Institute of Science Education and Research (IISER)-Pune, Dr. Homi Bhabha Road, Biology, Room#B-216, 1st Floor, Main Building, Pashan, Pune, Maharashtra, 411008, India
| | - Kundan Sengupta
- Indian Institute of Science Education and Research (IISER)-Pune, Dr. Homi Bhabha Road, Biology, Room#B-216, 1st Floor, Main Building, Pashan, Pune, Maharashtra, 411008, India.
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23
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Maurer M, Lammerding J. The Driving Force: Nuclear Mechanotransduction in Cellular Function, Fate, and Disease. Annu Rev Biomed Eng 2019; 21:443-468. [PMID: 30916994 DOI: 10.1146/annurev-bioeng-060418-052139] [Citation(s) in RCA: 137] [Impact Index Per Article: 27.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Cellular behavior is continuously affected by microenvironmental forces through the process of mechanotransduction, in which mechanical stimuli are rapidly converted to biochemical responses. Mounting evidence suggests that the nucleus itself is a mechanoresponsive element, reacting to cytoskeletal forces and mediating downstream biochemical responses. The nucleus responds through a host of mechanisms, including partial unfolding, conformational changes, and phosphorylation of nuclear envelope proteins; modulation of nuclear import/export; and altered chromatin organization, resulting in transcriptional changes. It is unclear which of these events present direct mechanotransduction processes and which are downstream of other mechanotransduction pathways. We critically review and discuss the current evidence for nuclear mechanotransduction, particularly in the context of stem cell fate, a largely unexplored topic, and in disease, where an improved understanding of nuclear mechanotransduction is beginning to open new treatment avenues. Finally, we discuss innovative technological developments that will allow outstanding questions in the rapidly growing field of nuclear mechanotransduction to be answered.
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Affiliation(s)
- Melanie Maurer
- Meinig School of Biomedical Engineering and Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, New York 14853, USA; ,
| | - Jan Lammerding
- Meinig School of Biomedical Engineering and Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, New York 14853, USA; ,
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24
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Vivante A, Brozgol E, Bronshtein I, Levi V, Garini Y. Chromatin dynamics governed by a set of nuclear structural proteins. Genes Chromosomes Cancer 2019; 58:437-451. [PMID: 30537111 DOI: 10.1002/gcc.22719] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2018] [Revised: 11/15/2018] [Accepted: 12/04/2018] [Indexed: 12/30/2022] Open
Abstract
During the past three decades, the study of nuclear and chromatin organization has become of great interest. The organization and dynamics of chromatin are directly responsible for many functions including gene regulation, genome replication, and maintenance. In order to better understand the details of these mechanisms, we need to understand the role of specific proteins that take part in these processes. The genome in the nucleus is organized in different length scales, ranging from the bead-like nucleosomes through topological associated domains up to chromosome territories. The mechanisms that maintain these structures, however, remain to be fully elucidated. Previous works highlighted the significance of lamin A, an important nucleoplasmic protein; however, there are other nuclear structural proteins that are also important for chromatin organization. Studying the organizational aspects of the nucleus is a complex task, and different methods have been developed and adopted for this purpose, including molecular and imaging methods. Here we describe the use of the live-cell imaging method and demonstrate that the dynamics of the nucleus is strongly related to its organizational mechanisms. We labeled different genomic sites in the nucleus and measured the effect of nuclear structural proteins on their dynamics. We studied lamin A, BAF, Emerin, lamin B, CTCF, and Cohesin and discuss how each of them affect chromatin dynamics. Our findings indicate that lamin A and BAF have a significant effect on chromosomes dynamics, while other proteins mildly affect the type of the diffusion while the volume of motion is not affected.
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Affiliation(s)
- Anat Vivante
- Physics Department and Nanotechnology Institute, Bar Ilan University, Ramat Gan, Israel
| | - Eugene Brozgol
- Physics Department and Nanotechnology Institute, Bar Ilan University, Ramat Gan, Israel
| | - Irena Bronshtein
- Physics Department and Nanotechnology Institute, Bar Ilan University, Ramat Gan, Israel
| | - Vered Levi
- Physics Department and Nanotechnology Institute, Bar Ilan University, Ramat Gan, Israel
| | - Yuval Garini
- Physics Department and Nanotechnology Institute, Bar Ilan University, Ramat Gan, Israel
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25
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Targeting of LRRC59 to the Endoplasmic Reticulum and the Inner Nuclear Membrane. Int J Mol Sci 2019; 20:ijms20020334. [PMID: 30650545 PMCID: PMC6359192 DOI: 10.3390/ijms20020334] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2018] [Revised: 01/08/2019] [Accepted: 01/10/2019] [Indexed: 01/12/2023] Open
Abstract
LRRC59 (leucine-rich repeat-containing protein 59) is a tail-anchored protein with a single transmembrane domain close to its C-terminal end that localizes to the endoplasmic reticulum (ER) and the nuclear envelope. Here, we investigate the mechanisms of membrane integration of LRRC59 and its targeting to the inner nuclear membrane (INM). Using purified microsomes, we show that LRRC59 can be post-translationally inserted into ER-derived membranes. The TRC-pathway, a major route for post-translational membrane insertion, is not required for LRRC59. Like emerin, another tail-anchored protein, LRRC59 reaches the INM, as demonstrated by rapamycin-dependent dimerization assays. Using different approaches to inhibit importin α/β-dependent nuclear import of soluble proteins, we show that the classic nuclear transport machinery does not play a major role in INM-targeting of LRRC59. Instead, the size of the cytoplasmic domain of LRRC59 is an important feature, suggesting that targeting is governed by passive diffusion.
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26
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Dutta S, Bhattacharyya M, Sengupta K. Changes in the Nuclear Envelope in Laminopathies. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1112:31-38. [PMID: 30637688 DOI: 10.1007/978-981-13-3065-0_3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/19/2023]
Abstract
Double-membrane-bound nucleus is the major organelle of every metazoan cell, which controls various nuclear processes like chromatin maintenance, DNA replication, transcription and nucleoskeleton-cytoskeleton coupling. Nuclear homeostasis depends on the integrity of nuclear membrane and associated proteins. Lamins, underlying the inner nuclear membrane (INM), play a crucial role in maintaining nuclear homeostasis. In this review, we have focussed on the disruption of nuclear homeostasis due to lamin A/C mutation which produces a plethora of diseases, termed as laminopathies.
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Affiliation(s)
- Subarna Dutta
- Biophysics & Structural Genomics Division, Saha Institute of Nuclear Physics, Kolkata, West Bengal, India
- Department of Biochemistry, University of Calcutta, Kolkata, West Bengal, India
| | | | - Kaushik Sengupta
- Biophysics & Structural Genomics Division, Saha Institute of Nuclear Physics, Kolkata, West Bengal, India.
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González-Cruz RD, Dahl KN, Darling EM. The Emerging Role of Lamin C as an Important LMNA Isoform in Mechanophenotype. Front Cell Dev Biol 2018; 6:151. [PMID: 30450357 PMCID: PMC6224339 DOI: 10.3389/fcell.2018.00151] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2018] [Accepted: 10/15/2018] [Indexed: 12/17/2022] Open
Abstract
Lamin A and lamin C isoforms of the gene LMNA are major structural and mechanotransductive components of the nuclear lamina. Previous reports have proposed lamin A as the isoform with the most dominant contributions to cellular mechanophenotype. Recently, expression of lamin C has also been shown to strongly correlate to cellular elastic and viscoelastic properties. Nevertheless, LMNA isoforms exist as part of a network that collectively provides structural integrity to the nucleus and their expression is ultimately regulated in a cell-specific manner. Thus, they have importance in mechanotransduction and structural integrity of the nucleus as well as potential candidates for biomarkers of whole-cell mechanophenotype. Therefore, a fuller discussion of lamin isoforms as mechanophenotypic biomarkers should compare both individual and ratiometric isoform contributions toward whole-cell mechanophenotype across different cell types. In this perspective, we discuss the distinctions between the mechanophenotypic correlations of individual and ratiometric lamins A:B1, C:B1, (A + C):B1, and C:A across cells from different lineages, demonstrating that the collective contribution of ratiometric lamin (A + C):B1 isoforms exhibited the strongest correlation to whole-cell stiffness. Additionally, we highlight the potential roles of lamin isoform ratios as indicators of mechanophenotypic change in differentiation and disease to demonstrate that the contributions of individual and collective lamin isoforms can occur as both static and dynamic biomarkers of mechanophenotype.
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Affiliation(s)
| | - Kris N Dahl
- Department of Chemical Engineering, Department of Biomedical Engineering, Carnegie Mellon University, Pittsburgh, PA, United States
| | - Eric M Darling
- Center for Biomedical Engineering, Brown University, Providence, RI, United States.,Department of Molecular Pharmacology, Physiology and Biotechnology, School of Engineering, Department of Orthopaedics, Brown University, Providence, RI, United States
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Steele-Stallard HB, Pinton L, Sarcar S, Ozdemir T, Maffioletti SM, Zammit PS, Tedesco FS. Modeling Skeletal Muscle Laminopathies Using Human Induced Pluripotent Stem Cells Carrying Pathogenic LMNA Mutations. Front Physiol 2018; 9:1332. [PMID: 30405424 PMCID: PMC6201196 DOI: 10.3389/fphys.2018.01332] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2018] [Accepted: 09/04/2018] [Indexed: 01/03/2023] Open
Abstract
Laminopathies are a clinically heterogeneous group of disorders caused by mutations in LMNA. The main proteins encoded by LMNA are Lamin A and C, which together with Lamin B1 and B2, form the nuclear lamina: a mesh-like structure located underneath the inner nuclear membrane. Laminopathies show striking tissue specificity, with subtypes affecting striated muscle, peripheral nerve, and adipose tissue, while others cause multisystem disease with accelerated aging. Although several pathogenic mechanisms have been proposed, the exact pathophysiology of laminopathies remains unclear, compounded by the rarity of these disorders and lack of easily accessible cell types to study. To overcome this limitation, we used induced pluripotent stem cells (iPSCs) from patients with skeletal muscle laminopathies such as LMNA-related congenital muscular dystrophy and limb-girdle muscular dystrophy 1B, to model disease phenotypes in vitro. iPSCs can be derived from readily accessible cell types, have unlimited proliferation potential and can be differentiated into cell types that would otherwise be difficult and invasive to obtain. iPSC lines from three skeletal muscle laminopathy patients were differentiated into inducible myogenic cells and myotubes. Disease-associated phenotypes were observed in these cells, including abnormal nuclear shape and mislocalization of nuclear lamina proteins. Nuclear abnormalities were less pronounced in monolayer cultures of terminally differentiated skeletal myotubes than in proliferating myogenic cells. Notably, skeletal myogenic differentiation of LMNA-mutant iPSCs in artificial muscle constructs improved detection of myonuclear abnormalities compared to conventional monolayer cultures across multiple pathogenic genotypes, providing a high-fidelity modeling platform for skeletal muscle laminopathies. Our results lay the foundation for future iPSC-based therapy development and screening platforms for skeletal muscle laminopathies.
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Affiliation(s)
- Heather B Steele-Stallard
- Department of Cell and Developmental Biology, University College London, London, United Kingdom.,Randall Centre for Cell and Molecular Biophysics, King's College London, London, United Kingdom
| | - Luca Pinton
- Department of Cell and Developmental Biology, University College London, London, United Kingdom.,Randall Centre for Cell and Molecular Biophysics, King's College London, London, United Kingdom
| | - Shilpita Sarcar
- Department of Cell and Developmental Biology, University College London, London, United Kingdom
| | - Tanel Ozdemir
- Department of Cell and Developmental Biology, University College London, London, United Kingdom.,Randall Centre for Cell and Molecular Biophysics, King's College London, London, United Kingdom
| | - Sara M Maffioletti
- Department of Cell and Developmental Biology, University College London, London, United Kingdom
| | - Peter S Zammit
- Randall Centre for Cell and Molecular Biophysics, King's College London, London, United Kingdom
| | - Francesco Saverio Tedesco
- Department of Cell and Developmental Biology, University College London, London, United Kingdom.,The Dubowitz Neuromuscular Centre, UCL Great Ormond Street Institute of Child Health, London, United Kingdom
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29
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Pradhan R, Ranade D, Sengupta K. Emerin modulates spatial organization of chromosome territories in cells on softer matrices. Nucleic Acids Res 2018; 46:5561-5586. [PMID: 29684168 PMCID: PMC6009696 DOI: 10.1093/nar/gky288] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2018] [Revised: 04/04/2018] [Accepted: 04/06/2018] [Indexed: 02/06/2023] Open
Abstract
Cells perceive and relay external mechanical forces into the nucleus through the nuclear envelope. Here we examined the effect of lowering substrate stiffness as a paradigm to address the impact of altered mechanical forces on nuclear structure-function relationships. RNA sequencing of cells on softer matrices revealed significant transcriptional imbalances, predominantly in chromatin associated processes and transcriptional deregulation of human Chromosome 1. Furthermore, 3-Dimensional fluorescence in situ hybridization (3D-FISH) analyses showed a significant mislocalization of Chromosome 1 and 19 Territories (CT) into the nuclear interior, consistent with their transcriptional deregulation. However, CT18 with relatively lower transcriptional dysregulation, also mislocalized into the nuclear interior. Furthermore, nuclear Lamins that regulate chromosome positioning, were mislocalized into the nuclear interior in response to lowered matrix stiffness. Notably, Lamin B2 overexpression retained CT18 near the nuclear periphery in cells on softer matrices. While, cells on softer matrices also activated emerin phosphorylation at a novel Tyr99 residue, the inhibition of which in a phospho-deficient mutant (emerinY99F), selectively retained chromosome 18 and 19 but not chromosome 1 territories at their conserved nuclear locations. Taken together, emerin functions as a key mechanosensor, that modulates the spatial organization of chromosome territories in the interphase nucleus.
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Affiliation(s)
- Roopali Pradhan
- Biology, Main Building, First Floor, Room#B-216, Indian Institute of Science Education and Research (IISER), Pune, Dr Homi Bhabha Road, Pashan, Pune 411008, Maharashtra, India
| | - Devika Ranade
- Biology, Main Building, First Floor, Room#B-216, Indian Institute of Science Education and Research (IISER), Pune, Dr Homi Bhabha Road, Pashan, Pune 411008, Maharashtra, India
| | - Kundan Sengupta
- Biology, Main Building, First Floor, Room#B-216, Indian Institute of Science Education and Research (IISER), Pune, Dr Homi Bhabha Road, Pashan, Pune 411008, Maharashtra, India
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30
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Naetar N, Ferraioli S, Foisner R. Lamins in the nuclear interior - life outside the lamina. J Cell Sci 2018; 130:2087-2096. [PMID: 28668931 DOI: 10.1242/jcs.203430] [Citation(s) in RCA: 107] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Nuclear lamins are components of the peripheral lamina that define the mechanical properties of nuclei and tether heterochromatin to the periphery. A-type lamins localize also to the nuclear interior, but the regulation and specific functions of this nucleoplasmic lamin pool are poorly understood. In this Commentary, we summarize known pathways that are potentially involved in the localization and dynamic behavior of intranuclear lamins, including their post-translational modifications and interactions with nucleoplasmic proteins, such as lamina-associated polypeptide 2α (LAP2α; encoded by TMPO). In addition, new data suggest that lamins in the nuclear interior have an important role in chromatin regulation and gene expression through dynamic binding to both hetero- and euchromatic genomic regions and promoter subdomains, thereby affecting epigenetic pathways and chromatin accessibility. Nucleoplasmic lamins also have a role in spatial chromatin organization and may be involved in mechanosignaling. In view of this newly emerging concept, we propose that the previously reported cellular phenotypes in lamin-linked diseases are, at least in part, rooted in an impaired regulation and/or function of the nucleoplasmic lamin A/C pool.
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Affiliation(s)
- Nana Naetar
- Center of Medical Biochemistry, Max F. Perutz Laboratories (MFPL), Medical University of Vienna, Vienna Biocenter (VBC), Dr.-Bohr-Gasse 9, Vienna A-1030, Austria
| | - Simona Ferraioli
- Center of Medical Biochemistry, Max F. Perutz Laboratories (MFPL), Medical University of Vienna, Vienna Biocenter (VBC), Dr.-Bohr-Gasse 9, Vienna A-1030, Austria
| | - Roland Foisner
- Center of Medical Biochemistry, Max F. Perutz Laboratories (MFPL), Medical University of Vienna, Vienna Biocenter (VBC), Dr.-Bohr-Gasse 9, Vienna A-1030, Austria
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31
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Ziat E, Mamchaoui K, Beuvin M, Nelson I, Azibani F, Spuler S, Bonne G, Bertrand AT. FHL1B Interacts with Lamin A/C and Emerin at the Nuclear Lamina and is Misregulated in Emery-Dreifuss Muscular Dystrophy. J Neuromuscul Dis 2018; 3:497-510. [PMID: 27911330 DOI: 10.3233/jnd-160169] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
BACKGROUND Emery-Dreifuss muscular dystrophy (EDMD) is associated with mutations in EMD and LMNA genes, encoding for the nuclear envelope proteins emerin and lamin A/C, indicating that EDMD is a nuclear envelope disease. We recently reported mutations in FHL1 gene in X-linked EDMD. FHL1 encodes FHL1A, and the two minor isoforms FHL1B and FHL1C. So far, none have been described at the nuclear envelope. OBJECTIVE To gain insight into the pathophysiology of EDMD, we focused our attention on the poorly characterized FHL1B isoform. METHODS The amount and the localisation of FHL1B were evaluated in control and diseased human primary myoblasts using immunofluorescence and western blotting. RESULTS We found that in addition to a cytoplasmic localization, this isoform strongly accumulated at the nuclear envelope of primary human myoblasts, like but independently of lamin A/C and emerin. During myoblast differentiation, we observed a major reduction of FHL1B protein expression, especially in the nucleus. Interestingly, we found elevated FHL1B expression level in myoblasts from an FHL1-related EDMD patient where the FHL1 mutation only affects FHL1A, as well as in myoblasts from an LMNA-related EDMD patient. CONCLUSIONS Altogether, the specific localization of FHL1B and its modulation in disease-patient's myoblasts confirmed FHL1-related EDMD as a nuclear envelope disease.
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Affiliation(s)
- Esma Ziat
- Sorbonne Universités, UPMC Univ Paris 06, INSERM UMRS974, CNRS FRE3617, Center of Research in Myology, F-75013 Paris, France.,Muscle Research Unit, Experimental and Clinical Research Center, A Joint Cooperation between Max-Delbrück-Center for Molecular Medicine and Charite Medical Faculty, Berlin, Germany
| | - Kamel Mamchaoui
- Sorbonne Universités, UPMC Univ Paris 06, INSERM UMRS974, CNRS FRE3617, Center of Research in Myology, F-75013 Paris, France
| | - Maud Beuvin
- Sorbonne Universités, UPMC Univ Paris 06, INSERM UMRS974, CNRS FRE3617, Center of Research in Myology, F-75013 Paris, France
| | - Isabelle Nelson
- Sorbonne Universités, UPMC Univ Paris 06, INSERM UMRS974, CNRS FRE3617, Center of Research in Myology, F-75013 Paris, France
| | - Feriel Azibani
- Sorbonne Universités, UPMC Univ Paris 06, INSERM UMRS974, CNRS FRE3617, Center of Research in Myology, F-75013 Paris, France
| | - Simone Spuler
- Muscle Research Unit, Experimental and Clinical Research Center, A Joint Cooperation between Max-Delbrück-Center for Molecular Medicine and Charite Medical Faculty, Berlin, Germany
| | - Gisèle Bonne
- Sorbonne Universités, UPMC Univ Paris 06, INSERM UMRS974, CNRS FRE3617, Center of Research in Myology, F-75013 Paris, France
| | - Anne T Bertrand
- Sorbonne Universités, UPMC Univ Paris 06, INSERM UMRS974, CNRS FRE3617, Center of Research in Myology, F-75013 Paris, France
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32
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Eisch V, Lu X, Gabriel D, Djabali K. Progerin impairs chromosome maintenance by depleting CENP-F from metaphase kinetochores in Hutchinson-Gilford progeria fibroblasts. Oncotarget 2017; 7:24700-18. [PMID: 27015553 PMCID: PMC5029735 DOI: 10.18632/oncotarget.8267] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2015] [Accepted: 03/04/2016] [Indexed: 01/26/2023] Open
Abstract
Hutchinson-Gilford progeria syndrome (HGPS, OMIM 176670) is a rare premature aging disorder that leads to death at an average age of 14.7 years due to myocardial infarction or stroke. The most common mutation in HGPS is at position G608G (GGC>GGT) within exon 11 of the LMNA gene. This mutation results in the deletion of 50 amino acids at the carboxyl-terminal tail of prelamin A, producing a truncated farnesylated protein called progerin. Lamins play important roles in the organization and structure of the nucleus. The nuclear build-up of progerin causes severe morphological and functional changes in interphase HGPS cells. In this study, we investigated whether progerin elicits spatiotemporal deviations in mitotic processes in HGPS fibroblasts. We analyzed the nuclear distribution of endogenous progerin during mitosis in relation to components of the nuclear lamina, nuclear envelope (NE) and nuclear pores. We found that progerin caused defects in chromosome segregation as early as metaphase, delayed NE reformation and trapped lamina components and inner NE proteins in the endoplasmic reticulum at the end of mitosis. Progerin displaced the centromere protein F (CENP-F) from metaphase chromosome kinetochores, which caused increased chromatin lagging, binucleated cells and genomic instability. This accumulation of progerin-dependent defects with each round of mitosis predisposes cells to premature senescence.
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Affiliation(s)
- Veronika Eisch
- Epigenetics of Aging, Department of Dermatology, TUM School of Medicine, Technical University Munich (TUM), Garching-Munich, Germany
| | - Xiang Lu
- Epigenetics of Aging, Department of Dermatology, TUM School of Medicine, Technical University Munich (TUM), Garching-Munich, Germany
| | - Diana Gabriel
- Epigenetics of Aging, Department of Dermatology, TUM School of Medicine, Technical University Munich (TUM), Garching-Munich, Germany
| | - Karima Djabali
- Epigenetics of Aging, Department of Dermatology, TUM School of Medicine, Technical University Munich (TUM), Garching-Munich, Germany
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33
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Gagliardi A, Besio R, Carnemolla C, Landi C, Armini A, Aglan M, Otaify G, Temtamy SA, Forlino A, Bini L, Bianchi L. Cytoskeleton and nuclear lamina affection in recessive osteogenesis imperfecta: A functional proteomics perspective. J Proteomics 2017; 167:46-59. [PMID: 28802583 PMCID: PMC5584732 DOI: 10.1016/j.jprot.2017.08.007] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2017] [Revised: 08/02/2017] [Accepted: 08/07/2017] [Indexed: 02/07/2023]
Abstract
Osteogenesis imperfecta (OI) is a collagen-related disorder associated to dominant, recessive or X-linked transmission, mainly caused by mutations in type I collagen genes or in genes involved in type I collagen metabolism. Among the recessive forms, OI types VII, VIII, and IX are due to mutations in CRTAP, P3H1, and PPIB genes, respectively. They code for the three components of the endoplasmic reticulum complex that catalyzes 3-hydroxylation of type I collagen α1Pro986. Under-hydroxylation of this residue leads to collagen structural abnormalities and results in moderate to lethal OI phenotype, despite the exact molecular mechanisms are still not completely clear. To shed light on these recessive forms, primary fibroblasts from OI patients with mutations in CRTAP (n=3), P3H1 (n=3), PPIB (n=1) genes and from controls (n=4) were investigated by a functional proteomic approach. Cytoskeleton and nucleoskeleton asset, protein fate, and metabolism were delineated as mainly affected. While western blot experiments confirmed altered expression of lamin A/C and cofilin-1, immunofluorescence analysis using antibody against lamin A/C and phalloidin showed an aberrant organization of nucleus and cytoskeleton. This is the first report describing an altered organization of intracellular structural proteins in recessive OI and pointing them as possible novel target for OI treatment. SIGNIFICANCE OI is a prototype for skeletal dysplasias. It is a highly heterogeneous collagen-related disorder with dominant, recessive and X-linked transmission. There is no definitive cure for this disease, thus a better understanding of the molecular basis of its pathophysiology is expected to contribute in identifying potential targets to develop new treatments. Based on this concept, we performed a functional proteomic study to delineate affected molecular pathways in primary fibroblasts from recessive OI patients, carrying mutations in CRTAP (OI type VII), P3H1 (OI type VIII), and PPIB (OI type IX) genes. Our analyses demonstrated the occurrence of an altered cytoskeleton and, for the first time in OI, of nuclear lamina organization. Hence, cytoskeleton and nucleoskeleton components may be considered as novel drug targets for clinical management of the disease. Finally, according to our analyses, OI emerged to share similar deregulated pathways and molecular aberrances, as previously described, with other rare disorders caused by different genetic defects. Those aberrances may provide common pharmacological targets to support classical clinical approach in treating different diseases.
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Affiliation(s)
- Assunta Gagliardi
- Functional Proteomics Laboratory, Department of Life Sciences, University of Siena, Siena, Italy; CIBIO, University of Trento, Trento, Italy
| | - Roberta Besio
- Department of Molecular Medicine, Biochemistry Unit, University of Pavia, Pavia, Italy
| | - Chiara Carnemolla
- Functional Proteomics Laboratory, Department of Life Sciences, University of Siena, Siena, Italy
| | - Claudia Landi
- Functional Proteomics Laboratory, Department of Life Sciences, University of Siena, Siena, Italy
| | - Alessandro Armini
- Functional Proteomics Laboratory, Department of Life Sciences, University of Siena, Siena, Italy
| | - Mona Aglan
- Department of Clinical Genetics, Human Genetics & Genome Research Division, Center of Excellence for Human Genetics, National Research Centre, Cairo, Egypt
| | - Ghada Otaify
- Department of Clinical Genetics, Human Genetics & Genome Research Division, Center of Excellence for Human Genetics, National Research Centre, Cairo, Egypt
| | - Samia A Temtamy
- Department of Clinical Genetics, Human Genetics & Genome Research Division, Center of Excellence for Human Genetics, National Research Centre, Cairo, Egypt
| | - Antonella Forlino
- Department of Molecular Medicine, Biochemistry Unit, University of Pavia, Pavia, Italy
| | - Luca Bini
- Functional Proteomics Laboratory, Department of Life Sciences, University of Siena, Siena, Italy
| | - Laura Bianchi
- Functional Proteomics Laboratory, Department of Life Sciences, University of Siena, Siena, Italy.
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Küchler P, Zimmermann G, Winzker M, Janning P, Waldmann H, Ziegler S. Identification of novel PDEδ interacting proteins. Bioorg Med Chem 2017; 26:1426-1434. [PMID: 28935183 DOI: 10.1016/j.bmc.2017.08.033] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2017] [Accepted: 08/20/2017] [Indexed: 12/15/2022]
Abstract
Prenylation is a post-translational modification that increases the affinity of proteins for membranes and mediates protein-protein interactions. The retinal rod rhodopsin-sensitive cGMP 3',5'-cyclic phosphodiesterase subunit delta (PDEδ) is a prenyl binding protein that is essential for the shuttling of small GTPases between different membrane compartments and, thus, for their proper functioning. Although the prenylome comprises up to 2% of the mammalian proteome, only few prenylated proteins are known to interact with PDEδ. A proteome-wide approach was employed to map the PDEδ interactome among the prenylome and revealed RAB23, CDC42 and CNP as novel PDEδ interacting proteins. Moreover, PDEδ associates with the lamin A mutant progerin in a prenyl-dependent manner. These findings shed new light on the role of PDEδ in binding (and regulating) prenylated proteins in cells.
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Affiliation(s)
- Philipp Küchler
- Department of Chemical Biology, Max-Planck-Institut für Molekulare Physiologie, Otto-Hahn-Straße 11, 44227 Dortmund, Germany; Lehrbereich Chemische Biologie, Fakultät Chemie, Technische Universität Dortmund, Otto-Hahn-Straße 6, 44227 Dortmund, Germany
| | - Gunther Zimmermann
- Department of Chemical Biology, Max-Planck-Institut für Molekulare Physiologie, Otto-Hahn-Straße 11, 44227 Dortmund, Germany; Lehrbereich Chemische Biologie, Fakultät Chemie, Technische Universität Dortmund, Otto-Hahn-Straße 6, 44227 Dortmund, Germany
| | - Michael Winzker
- Department of Chemical Biology, Max-Planck-Institut für Molekulare Physiologie, Otto-Hahn-Straße 11, 44227 Dortmund, Germany; Lehrbereich Chemische Biologie, Fakultät Chemie, Technische Universität Dortmund, Otto-Hahn-Straße 6, 44227 Dortmund, Germany
| | - Petra Janning
- Department of Chemical Biology, Max-Planck-Institut für Molekulare Physiologie, Otto-Hahn-Straße 11, 44227 Dortmund, Germany
| | - Herbert Waldmann
- Department of Chemical Biology, Max-Planck-Institut für Molekulare Physiologie, Otto-Hahn-Straße 11, 44227 Dortmund, Germany; Lehrbereich Chemische Biologie, Fakultät Chemie, Technische Universität Dortmund, Otto-Hahn-Straße 6, 44227 Dortmund, Germany.
| | - Slava Ziegler
- Department of Chemical Biology, Max-Planck-Institut für Molekulare Physiologie, Otto-Hahn-Straße 11, 44227 Dortmund, Germany.
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35
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Abstract
Cardiac and skeletal striated muscles are intricately designed machines responsible for muscle contraction. Coordination of the basic contractile unit, the sarcomere, and the complex cytoskeletal networks are critical for contractile activity. The sarcomere is comprised of precisely organized individual filament systems that include thin (actin), thick (myosin), titin, and nebulin. Connecting the sarcomere to other organelles (e.g., mitochondria and nucleus) and serving as the scaffold to maintain cellular integrity are the intermediate filaments. The costamere, on the other hand, tethers the sarcomere to the cell membrane. Unique structures like the intercalated disc in cardiac muscle and the myotendinous junction in skeletal muscle help synchronize and transmit force. Intense investigation has been done on many of the proteins that make up these cytoskeletal assemblies. Yet the details of their function and how they interconnect have just started to be elucidated. A vast number of human myopathies are contributed to mutations in muscle proteins; thus understanding their basic function provides a mechanistic understanding of muscle disorders. In this review, we highlight the components of striated muscle with respect to their interactions, signaling pathways, functions, and connections to disease. © 2017 American Physiological Society. Compr Physiol 7:891-944, 2017.
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Affiliation(s)
- Christine A Henderson
- Department of Cellular and Molecular Medicine, The University of Arizona, Tucson, Arizona, USA.,Sarver Molecular Cardiovascular Research Program, The University of Arizona, Tucson, Arizona, USA
| | - Christopher G Gomez
- Department of Cellular and Molecular Medicine, The University of Arizona, Tucson, Arizona, USA.,Sarver Molecular Cardiovascular Research Program, The University of Arizona, Tucson, Arizona, USA
| | - Stefanie M Novak
- Department of Cellular and Molecular Medicine, The University of Arizona, Tucson, Arizona, USA.,Sarver Molecular Cardiovascular Research Program, The University of Arizona, Tucson, Arizona, USA
| | - Lei Mi-Mi
- Department of Cellular and Molecular Medicine, The University of Arizona, Tucson, Arizona, USA.,Sarver Molecular Cardiovascular Research Program, The University of Arizona, Tucson, Arizona, USA
| | - Carol C Gregorio
- Department of Cellular and Molecular Medicine, The University of Arizona, Tucson, Arizona, USA.,Sarver Molecular Cardiovascular Research Program, The University of Arizona, Tucson, Arizona, USA
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36
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Le Thanh P, Meinke P, Korfali N, Srsen V, Robson MI, Wehnert M, Schoser B, Sewry CA, Schirmer EC. Immunohistochemistry on a panel of Emery-Dreifuss muscular dystrophy samples reveals nuclear envelope proteins as inconsistent markers for pathology. Neuromuscul Disord 2016; 27:338-351. [PMID: 28214269 PMCID: PMC5380655 DOI: 10.1016/j.nmd.2016.12.003] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2016] [Revised: 11/22/2016] [Accepted: 12/09/2016] [Indexed: 11/08/2022]
Abstract
Altered distribution of EDMD-linked proteins is not a general characteristic of EDMD. Tissue-specific proteins exhibit altered distributions in some EDMD patients. Variation in redistributed proteins in EDMD may underlie its clinical variability.
Reports of aberrant distribution for some nuclear envelope proteins in cells expressing a few Emery–Dreifuss muscular dystrophy mutations raised the possibility that such protein redistribution could underlie pathology and/or be diagnostic. However, this disorder is linked to 8 different genes encoding nuclear envelope proteins, raising the question of whether a particular protein is most relevant. Therefore, myoblast/fibroblast cultures from biopsy and tissue sections from a panel of nine Emery–Dreifuss muscular dystrophy patients (4 male, 5 female) including those carrying emerin and FHL1 (X-linked) and several lamin A (autosomal dominant) mutations were stained for the proteins linked to the disorder. As tissue-specific nuclear envelope proteins have been postulated to mediate the tissue-specific pathologies of different nuclear envelopathies, patient samples were also stained for several muscle-specific nuclear membrane proteins. Although linked proteins nesprin 1 and SUN2 and muscle-specific proteins NET5/Samp1 and Tmem214 yielded aberrant distributions in individual patient cells, none exhibited defects through the larger patient panel. Muscle-specific Tmem38A normally appeared in both the nuclear envelope and sarcoplasmic reticulum, but most patient samples exhibited a moderate redistribution favouring the sarcoplasmic reticulum. The absence of striking uniform defects in nuclear envelope protein distribution indicates that such staining will be unavailing for general diagnostics, though it remains possible that specific mutations exhibiting protein distribution defects might reflect a particular clinical variant. These findings further argue that multiple pathways can lead to the generally similar pathologies of this disorder while at the same time the different cellular phenotypes observed possibly may help explain the considerable clinical variation of EDMD.
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Affiliation(s)
- Phu Le Thanh
- Wellcome Trust Centre for Cell Biology, University of Edinburgh, Edinburgh, UK
| | - Peter Meinke
- Wellcome Trust Centre for Cell Biology, University of Edinburgh, Edinburgh, UK; Friedrich-Baur-Institute, Ludwig Maximilian University, Munich, Germany
| | - Nadia Korfali
- Wellcome Trust Centre for Cell Biology, University of Edinburgh, Edinburgh, UK
| | - Vlastimil Srsen
- Wellcome Trust Centre for Cell Biology, University of Edinburgh, Edinburgh, UK
| | - Michael I Robson
- Wellcome Trust Centre for Cell Biology, University of Edinburgh, Edinburgh, UK
| | - Manfred Wehnert
- Institute of Human Genetics, University of Greifswald, Greifswald, Germany
| | - Benedikt Schoser
- Friedrich-Baur-Institute, Ludwig Maximilian University, Munich, Germany
| | - Caroline A Sewry
- Dubowitz Neuromuscular Centre, Great Ormond Street Hospital for Children NHS Trust, London, UK
| | - Eric C Schirmer
- Wellcome Trust Centre for Cell Biology, University of Edinburgh, Edinburgh, UK.
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37
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The effect of the lamin A and its mutants on nuclear structure, cell proliferation, protein stability, and mobility in embryonic cells. Chromosoma 2016; 126:501-517. [PMID: 27534416 PMCID: PMC5509783 DOI: 10.1007/s00412-016-0610-9] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2016] [Revised: 07/11/2016] [Accepted: 08/02/2016] [Indexed: 01/26/2023]
Abstract
LMNA gene encodes for nuclear intermediate filament proteins lamin A/C. Mutations in this gene lead to a spectrum of genetic disorders, collectively referred to as laminopathies. Lamin A/C are widely expressed in most differentiated somatic cells but not in early embryos and some undifferentiated cells. To investigate the role of lamin A/C in cell phenotype maintenance and differentiation, which could be a determinant of the pathogenesis of laminopathies, we examined the role played by exogenous lamin A and its mutants in differentiated cell lines (HeLa, NHDF) and less-differentiated HEK 293 cells. We introduced exogenous wild-type and mutated (H222P, L263P, E358K D446V, and ∆50) lamin A into different cell types and analyzed proteins’ impact on proliferation, protein mobility, and endogenous nuclear envelope protein distribution. The mutants give rise to a broad spectrum of nuclear phenotypes and relocate lamin C. The mutations ∆50 and D446V enhance proliferation in comparison to wild-type lamin A and control cells, but no changes in exogenous protein mobility measured by FRAP were observed. Interestingly, although transcripts for lamins A and C are at similar level in HEK 293 cells, only lamin C protein is detected in western blots. Also, exogenous lamin A and its mutants, when expressed in HEK 293 cells underwent posttranscriptional processing. Overall, our results provide new insight into the maintenance of lamin A in less-differentiated cells. Embryonic cells are very sensitive to lamin A imbalance, and its upregulation disturbs lamin C, which may influence gene expression and many regulatory pathways.
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Bell ES, Lammerding J. Causes and consequences of nuclear envelope alterations in tumour progression. Eur J Cell Biol 2016; 95:449-464. [PMID: 27397692 DOI: 10.1016/j.ejcb.2016.06.007] [Citation(s) in RCA: 71] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2016] [Revised: 06/22/2016] [Accepted: 06/22/2016] [Indexed: 12/31/2022] Open
Abstract
Morphological changes in the size and shape of the nucleus are highly prevalent in cancer, but the underlying molecular mechanisms and the functional relevance remain poorly understood. Nuclear envelope proteins, which can modulate nuclear shape and organization, have emerged as key components in a variety of signalling pathways long implicated in tumourigenesis and metastasis. The expression of nuclear envelope proteins is altered in many cancers, and changes in levels of nuclear envelope proteins lamins A and C are associated with poor prognosis in multiple human cancers. In this review we highlight the role of the nuclear envelope in different processes important for tumour initiation and cancer progression, with a focus on lamins A and C. Lamin A/C controls many cellular processes with key roles in cancer, including cell invasion, stemness, genomic stability, signal transduction, transcriptional regulation, and resistance to mechanical stress. In addition, we discuss potential mechanisms mediating the changes in lamin levels observed in many cancers. A better understanding of cause-and-effect relationships between lamin expression and tumour progression could reveal important mechanisms for coordinated regulation of oncogenic processes, and indicate therapeutic vulnerabilities that could be exploited for improved patient outcome.
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Affiliation(s)
- Emily S Bell
- Meinig School of Biomedical Engineering & Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, NY 14853, United States
| | - Jan Lammerding
- Meinig School of Biomedical Engineering & Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, NY 14853, United States.
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Gesson K, Rescheneder P, Skoruppa MP, von Haeseler A, Dechat T, Foisner R. A-type lamins bind both hetero- and euchromatin, the latter being regulated by lamina-associated polypeptide 2 alpha. Genome Res 2016; 26:462-73. [PMID: 26798136 PMCID: PMC4817770 DOI: 10.1101/gr.196220.115] [Citation(s) in RCA: 135] [Impact Index Per Article: 16.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2015] [Accepted: 01/19/2016] [Indexed: 11/24/2022]
Abstract
Lamins are components of the peripheral nuclear lamina and interact with heterochromatic genomic regions, termed lamina-associated domains (LADs). In contrast to lamin B1 being primarily present at the nuclear periphery, lamin A/C also localizes throughout the nucleus, where it associates with the chromatin-binding protein lamina-associated polypeptide (LAP) 2 alpha. Here, we show that lamin A/C also interacts with euchromatin, as determined by chromatin immunoprecipitation of euchromatin- and heterochromatin-enriched samples. By way of contrast, lamin B1 was only found associated with heterochromatin. Euchromatic regions occupied by lamin A/C overlap with those bound by LAP2alpha, and lack of LAP2alpha in LAP2alpha-deficient cells shifts binding of lamin A/C toward more heterochromatic regions. These alterations in lamin A/C-chromatin interactions correlate with changes in epigenetic histone marks in euchromatin but do not significantly affect gene expression. Loss of lamin A/C in heterochromatic regions in LAP2alpha-deficient cells, however, correlated with increased gene expression. Our data show a novel role of nucleoplasmic lamin A/C and LAP2alpha in regulating euchromatin.
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Affiliation(s)
- Kevin Gesson
- Department of Medical Biochemistry, Medical University of Vienna, A-1030 Vienna, Austria
| | - Philipp Rescheneder
- Center for Integrative Bioinformatics Vienna, Max F. Perutz Laboratories (MFPL), Medical University of Vienna and University of Vienna, Vienna Biocenter (VBC), A-1030 Vienna, Austria
| | - Michael P Skoruppa
- Department of Medical Biochemistry, Medical University of Vienna, A-1030 Vienna, Austria
| | - Arndt von Haeseler
- Center for Integrative Bioinformatics Vienna, Max F. Perutz Laboratories (MFPL), Medical University of Vienna and University of Vienna, Vienna Biocenter (VBC), A-1030 Vienna, Austria; Bioinformatics and Computational Biology, Faculty of Computer Science, University of Vienna, A-1030 Vienna, Austria
| | - Thomas Dechat
- Department of Medical Biochemistry, Medical University of Vienna, A-1030 Vienna, Austria
| | - Roland Foisner
- Department of Medical Biochemistry, Medical University of Vienna, A-1030 Vienna, Austria
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MCLIP Detection of Novel Protein–Protein Interactions at the Nuclear Envelope. Methods Enzymol 2016; 569:503-15. [DOI: 10.1016/bs.mie.2015.08.022] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/16/2023]
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Herrada I, Samson C, Velours C, Renault L, Östlund C, Chervy P, Puchkov D, Worman HJ, Buendia B, Zinn-Justin S. Muscular Dystrophy Mutations Impair the Nuclear Envelope Emerin Self-assembly Properties. ACS Chem Biol 2015; 10:2733-42. [PMID: 26415001 DOI: 10.1021/acschembio.5b00648] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
More than 100 genetic mutations causing X-linked Emery-Dreifuss muscular dystrophy have been identified in the gene encoding the integral inner nuclear membrane protein emerin. Most mutations are nonsense or frameshift mutations that lead to the absence of emerin in cells. Only very few cases are due to missense or short in-frame deletions. Molecular mechanisms explaining the corresponding emerin variants' loss of function are particularly difficult to identify because of the mostly intrinsically disordered state of the emerin nucleoplasmic region. We now demonstrate that this EmN region can be produced as a disordered monomer, as revealed by nuclear magnetic resonance, but rapidly self-assembles in vitro. Increases in concentration and temperature favor the formation of long curvilinear filaments with diameters of approximately 10 nm, as observed by electron microscopy. Assembly of these filaments can be followed by fluorescence through Thioflavin-T binding and by Fourier-transform Infrared spectrometry through formation of β-structures. Analysis of the assembly properties of five EmN variants reveals that del95-99 and Q133H impact filament assembly capacities. In cells, these variants are located at the nuclear envelope, but the corresponding quantities of emerin-emerin and emerin-lamin proximities are decreased compared to wild-type protein. Furthermore, variant P183H favors EmN aggregation in vitro, and variant P183T provokes emerin accumulation in cytoplasmic foci in cells. Substitution of residue Pro183 might systematically favor oligomerization, leading to emerin aggregation and mislocalization in cells. Our results suggest that emerin self-assembly is necessary for its proper function and that a loss of either the protein itself or its ability to self-assemble causes muscular dystrophy.
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Affiliation(s)
- Isaline Herrada
- Laboratoire
de Biologie Structurale et Radiobiologie, Institute for Integrative Biology of the Cell (I2BC), CEA Saclay Bât. 144, 91191 Gif-sur-Yvette Cedex, France
| | - Camille Samson
- Laboratoire
de Biologie Structurale et Radiobiologie, Institute for Integrative Biology of the Cell (I2BC), CEA Saclay Bât. 144, 91191 Gif-sur-Yvette Cedex, France
| | - Christophe Velours
- Laboratoire
d’Enzymologie et Biochimie Structurales, Institute for Integrative Biology of the Cell (I2BC), CNRS Bât.34, 1 avenue de
la terrasse, 91190 Gif-sur-Yvette, France
| | - Louis Renault
- Laboratoire
d’Enzymologie et Biochimie Structurales, Institute for Integrative Biology of the Cell (I2BC), CNRS Bât.34, 1 avenue de
la terrasse, 91190 Gif-sur-Yvette, France
| | - Cecilia Östlund
- Department
of Medicine and Department of Pathology and Cell Biology, College
of Physicians and Surgeons, Columbia University, 630 West 168th Street, New York, New York 10032, United States
| | - Pierre Chervy
- Laboratoire
de Biologie Structurale et Radiobiologie, Institute for Integrative Biology of the Cell (I2BC), CEA Saclay Bât. 144, 91191 Gif-sur-Yvette Cedex, France
| | - Dmytro Puchkov
- Department
of Molecular Pharmacology and Cell Biology, Leibniz-Institut für Molecular Pharmakologie (FMP), 13125 Berlin, Germany
| | - Howard J Worman
- Department
of Medicine and Department of Pathology and Cell Biology, College
of Physicians and Surgeons, Columbia University, 630 West 168th Street, New York, New York 10032, United States
| | - Brigitte Buendia
- Laboratoire
de Physiologie du Muscle Strié, Université Paris Diderot-Paris 7, CNRS, UMR 8251, Institut de Biologie
Fonctionnelle et Adaptative, 4 rue
M.A. Lagroua Weill Halle, 75205 Paris Cedex 13, France
| | - Sophie Zinn-Justin
- Laboratoire
de Biologie Structurale et Radiobiologie, Institute for Integrative Biology of the Cell (I2BC), CEA Saclay Bât. 144, 91191 Gif-sur-Yvette Cedex, France
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Pfaff J, Rivera Monroy J, Jamieson C, Rajanala K, Vilardi F, Schwappach B, Kehlenbach RH. Emery-Dreifuss muscular dystrophy mutations impair TRC40-mediated targeting of emerin to the inner nuclear membrane. J Cell Sci 2015; 129:502-16. [PMID: 26675233 DOI: 10.1242/jcs.179333] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2015] [Accepted: 12/14/2015] [Indexed: 11/20/2022] Open
Abstract
Emerin is a tail-anchored protein that is found predominantly at the inner nuclear membrane (INM), where it associates with components of the nuclear lamina. Mutations in the emerin gene cause Emery-Dreifuss muscular dystrophy (EDMD), an X-linked recessive disease. Here, we report that the TRC40/GET pathway for post-translational insertion of tail-anchored proteins into membranes is involved in emerin-trafficking. Using proximity ligation assays, we show that emerin interacts with TRC40 in situ. Emerin expressed in bacteria or in a cell-free lysate was inserted into microsomal membranes in an ATP- and TRC40-dependent manner. Dominant-negative fragments of the TRC40-receptor proteins WRB and CAML (also known as CAMLG) inhibited membrane insertion. A rapamycin-based dimerization assay revealed correct transport of wild-type emerin to the INM, whereas TRC40-binding, membrane integration and INM-targeting of emerin mutant proteins that occur in EDMD was disturbed. Our results suggest that the mode of membrane integration contributes to correct targeting of emerin to the INM.
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Affiliation(s)
- Janine Pfaff
- Department of Molecular Biology, Faculty of Medicine, Georg-August-University, GZMB, Humboldtallee 23, Göttingen 37073, Germany
| | - Jhon Rivera Monroy
- Department of Molecular Biology, Faculty of Medicine, Georg-August-University, GZMB, Humboldtallee 23, Göttingen 37073, Germany
| | - Cara Jamieson
- Department of Molecular Biology, Faculty of Medicine, Georg-August-University, GZMB, Humboldtallee 23, Göttingen 37073, Germany
| | - Kalpana Rajanala
- Department of Molecular Biology, Faculty of Medicine, Georg-August-University, GZMB, Humboldtallee 23, Göttingen 37073, Germany
| | - Fabio Vilardi
- Department of Molecular Biology, Faculty of Medicine, Georg-August-University, GZMB, Humboldtallee 23, Göttingen 37073, Germany
| | - Blanche Schwappach
- Department of Molecular Biology, Faculty of Medicine, Georg-August-University, GZMB, Humboldtallee 23, Göttingen 37073, Germany Max-Planck Institute for Biophysical Chemistry, Göttingen 37077, Germany
| | - Ralph H Kehlenbach
- Department of Molecular Biology, Faculty of Medicine, Georg-August-University, GZMB, Humboldtallee 23, Göttingen 37073, Germany
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Boone PM, Yuan B, Gu S, Ma Z, Gambin T, Gonzaga-Jauregui C, Jain M, Murdock TJ, White JJ, Jhangiani SN, Walker K, Wang Q, Muzny DM, Gibbs RA, Hejtmancik JF, Lupski JR, Posey JE, Lewis RA. Hutterite-type cataract maps to chromosome 6p21.32-p21.31, cosegregates with a homozygous mutation in LEMD2, and is associated with sudden cardiac death. Mol Genet Genomic Med 2015; 4:77-94. [PMID: 26788539 PMCID: PMC4707028 DOI: 10.1002/mgg3.181] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2015] [Revised: 09/22/2015] [Accepted: 09/28/2015] [Indexed: 12/25/2022] Open
Abstract
BACKGROUND Juvenile-onset cataracts are known among the Hutterites of North America. Despite being identified over 30 years ago, this autosomal recessive condition has not been mapped, and the disease gene is unknown. METHODS We performed whole exome sequencing of three Hutterite-type cataract trios and follow-up genotyping and mapping in four extended kindreds. RESULTS Trio exomes enabled genome-wide autozygosity mapping, which localized the disease gene to a 9.5-Mb region on chromosome 6p. This region contained two candidate variants, LEMD2 c.T38G and MUC21 c.665delC. Extended pedigrees recruited for variant genotyping revealed multiple additional relatives with juvenile-onset cataract, as well as six deceased relatives with both cataracts and sudden cardiac death. The candidate variants were genotyped in 84 family members, including 17 with cataracts; only the variant in LEMD2 cosegregated with cataracts (LOD = 9.62). SNP-based fine mapping within the 9.5 Mb linked region supported this finding by refining the cataract locus to a 0.5- to 2.9-Mb subregion (6p21.32-p21.31) containing LEMD2 but not MUC21. LEMD2 is expressed in mouse and human lenses and encodes a LEM domain-containing protein; the c.T38G missense mutation is predicted to mutate a highly conserved residue within this domain (p.Leu13Arg). CONCLUSION We performed a genetic and genomic study of Hutterite-type cataract and found evidence for an association of this phenotype with sudden cardiac death. Using combined genetic and genomic approaches, we mapped cataracts to a small portion of chromosome 6 and propose that they result from a homozygous missense mutation in LEMD2.
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Affiliation(s)
- Philip M Boone
- Department of Molecular and Human Genetics Baylor College of Medicine Houston Texas
| | - Bo Yuan
- Department of Molecular and Human Genetics Baylor College of Medicine Houston Texas
| | - Shen Gu
- Department of Molecular and Human Genetics Baylor College of Medicine Houston Texas
| | - Zhiwei Ma
- Ophthalmic Genetics and Visual Function Branch National Eye Institute Rockville Maryland
| | - Tomasz Gambin
- Department of Molecular and Human Genetics Baylor College of Medicine Houston Texas
| | | | - Mahim Jain
- Department of Molecular and Human Genetics Baylor College of Medicine Houston Texas
| | | | - Janson J White
- Department of Molecular and Human Genetics Baylor College of Medicine Houston Texas
| | | | - Kimberly Walker
- Human Genome Sequencing Center Baylor College of Medicine Houston Texas
| | - Qiaoyan Wang
- Human Genome Sequencing Center Baylor College of Medicine Houston Texas
| | - Donna M Muzny
- Human Genome Sequencing Center Baylor College of Medicine Houston Texas
| | - Richard A Gibbs
- Department of Molecular and Human GeneticsBaylor College of MedicineHoustonTexas; Human Genome Sequencing CenterBaylor College of MedicineHoustonTexas
| | - J Fielding Hejtmancik
- Ophthalmic Genetics and Visual Function Branch National Eye Institute Rockville Maryland
| | - James R Lupski
- Department of Molecular and Human GeneticsBaylor College of MedicineHoustonTexas; Human Genome Sequencing CenterBaylor College of MedicineHoustonTexas; Department of PediatricsBaylor College of MedicineHoustonTexas; Texas Children's HospitalHoustonTexas
| | - Jennifer E Posey
- Department of Molecular and Human Genetics Baylor College of Medicine Houston Texas
| | - Richard A Lewis
- Department of Molecular and Human GeneticsBaylor College of MedicineHoustonTexas; Department of PediatricsBaylor College of MedicineHoustonTexas; Texas Children's HospitalHoustonTexas; Department of OphthalmologyBaylor College of MedicineHoustonTexas; Department of MedicineBaylor College of MedicineHoustonTexas
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Guo Y, Zheng Y. Lamins position the nuclear pores and centrosomes by modulating dynein. Mol Biol Cell 2015; 26:3379-89. [PMID: 26246603 PMCID: PMC4591684 DOI: 10.1091/mbc.e15-07-0482] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2015] [Accepted: 07/29/2015] [Indexed: 12/30/2022] Open
Abstract
Nuclear lamins counterbalance dynein forces on nuclear pore complexes through BICD2 and ensure even nuclear pore complex distribution and proper centrosome separation at prophase. Lamins, the type V nuclear intermediate filament proteins, are reported to function in both interphase and mitosis. For example, lamin deletion in various cell types can lead to an uneven distribution of the nuclear pore complexes (NPCs) in the interphase nuclear envelope, whereas deletion of B-type lamins results in spindle orientation defects in mitotic neural progenitor cells. How lamins regulate these functions is unknown. Using mouse cells deleted of different combinations or all lamins, we show that lamins are required to prevent the aggregation of NPCs in the nuclear envelope near centrosomes in late G2 and prophase. This asymmetric NPC distribution in the absence of lamins is caused by dynein forces acting on NPCs via the dynein adaptor BICD2. We further show that asymmetric NPC distribution upon lamin depletion disrupts the distribution of BICD2 and p150 dynactin on the nuclear envelope at prophase, which results in inefficient dynein-driven centrosome separation during prophase. Therefore lamins regulate microtubule-based motor forces in vivo to ensure proper NPC distribution in interphase and centrosome separation in the mitotic prophase.
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Affiliation(s)
- Yuxuan Guo
- Department of Biology, Johns Hopkins University, Baltimore, MD 21218; Department of Embryology, Carnegie Institution for Science, Baltimore, MD 21218
| | - Yixian Zheng
- Department of Biology, Johns Hopkins University, Baltimore, MD 21218; Department of Embryology, Carnegie Institution for Science, Baltimore, MD 21218
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Scharner J, Figeac N, Ellis JA, Zammit PS. Ameliorating pathogenesis by removing an exon containing a missense mutation: a potential exon-skipping therapy for laminopathies. Gene Ther 2015; 22:503-15. [PMID: 25832542 DOI: 10.1038/gt.2015.8] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2014] [Revised: 12/18/2014] [Accepted: 12/30/2014] [Indexed: 01/07/2023]
Abstract
Exon skipping, as a therapy to restore a reading frame or switch protein isoforms, is under clinical trial. We hypothesised that removing an in-frame exon containing a mutation could also improve pathogenic phenotypes. Our model is laminopathies: incurable tissue-specific degenerative diseases associated with LMNA mutations. LMNA encodes A-type lamins, that together with B-type lamins, form the nuclear lamina. Lamins contain an alpha-helical central rod domain composed of multiple heptad repeats. Eliminating LMNA exon 3 or 5 removes six heptad repeats, so shortens, but should not otherwise significantly alter, the alpha-helix. Human Lamin A or Lamin C with a deletion corresponding to amino acids encoded by exon 5 (Lamin A/C-Δ5) localised normally in murine lmna-null cells, rescuing both nuclear shape and endogenous Lamin B1/emerin distribution. However, Lamin A carrying pathogenic mutations in exon 3 or 5, or Lamin A/C-Δ3, did not. Furthermore, Lamin A/C-Δ5 was not deleterious to wild-type cells, unlike the other Lamin A mutants including Lamin A/C-Δ3. Thus Lamin A/C-Δ5 function as effectively as wild-type Lamin A/C and better than mutant versions. Antisense oligonucleotides skipped LMNA exon 5 in human cells, demonstrating the possibility of treating certain laminopathies with this approach. This proof-of-concept is the first to report the therapeutic potential of exon skipping for diseases arising from missense mutations.
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Affiliation(s)
- J Scharner
- Randall Division of Cell and Molecular Biophysics, King's College London, London, UK
| | - N Figeac
- Randall Division of Cell and Molecular Biophysics, King's College London, London, UK
| | - J A Ellis
- Randall Division of Cell and Molecular Biophysics, King's College London, London, UK
| | - P S Zammit
- Randall Division of Cell and Molecular Biophysics, King's College London, London, UK
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Amendola M, van Steensel B. Nuclear lamins are not required for lamina-associated domain organization in mouse embryonic stem cells. EMBO Rep 2015; 16:610-7. [PMID: 25784758 DOI: 10.15252/embr.201439789] [Citation(s) in RCA: 77] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2014] [Accepted: 02/16/2015] [Indexed: 11/09/2022] Open
Abstract
In mammals, the nuclear lamina interacts with hundreds of large genomic regions, termed lamina-associated domains (LADs) that are generally in a transcriptionally repressed state. Lamins form the major structural component of the lamina and have been reported to bind DNA and chromatin. Here, we systematically evaluate whether lamins are necessary for the LAD organization in murine embryonic stem cells. Surprisingly, removal of essentially all lamins does not have any detectable effect on the genome-wide interaction pattern of chromatin with emerin, a marker of the inner nuclear membrane. This suggests that other components of the lamina mediate these interactions.
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Affiliation(s)
- Mario Amendola
- Division of Gene Regulation, Netherlands Cancer Institute, Amsterdam, the Netherlands
| | - Bas van Steensel
- Division of Gene Regulation, Netherlands Cancer Institute, Amsterdam, the Netherlands
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Abstract
The intermediate filament proteins, A- and B-type lamins, form the nuclear lamina scaffold adjacent to the inner nuclear membrane. Lamins also contribute to chromatin regulation and various signaling pathways affecting gene expression. In this review, Osmanagic-Myers et al. focus on the role of nuclear lamins in mechanosensing and also discuss how disease-linked lamin mutants may impair the response of cells to mechanical stimuli and influence the properties of the extracellular matrix. The intermediate filament proteins, A- and B-type lamins, form the nuclear lamina scaffold adjacent to the inner nuclear membrane. B-type lamins confer elasticity, while A-type lamins lend viscosity and stiffness to nuclei. Lamins also contribute to chromatin regulation and various signaling pathways affecting gene expression. The mechanical roles of lamins and their functions in gene regulation are often viewed as independent activities, but recent findings suggest a highly cross-linked and interdependent regulation of these different functions, particularly in mechanosignaling. In this newly emerging concept, lamins act as a “mechanostat” that senses forces from outside and responds to tension by reinforcing the cytoskeleton and the extracellular matrix. A-type lamins, emerin, and the linker of the nucleoskeleton and cytoskeleton (LINC) complex directly transmit forces from the extracellular matrix into the nucleus. These mechanical forces lead to changes in the molecular structure, modification, and assembly state of A-type lamins. This in turn activates a tension-induced “inside-out signaling” through which the nucleus feeds back to the cytoskeleton and the extracellular matrix to balance outside and inside forces. These functions regulate differentiation and may be impaired in lamin-linked diseases, leading to cellular phenotypes, particularly in mechanical load-bearing tissues.
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Bera M, Kotamarthi HC, Dutta S, Ray A, Ghosh S, Bhattacharyya D, Ainavarapu SRK, Sengupta K. Characterization of unfolding mechanism of human lamin A Ig fold by single-molecule force spectroscopy-implications in EDMD. Biochemistry 2014; 53:7247-58. [PMID: 25343322 DOI: 10.1021/bi500726f] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
A- and B-type lamins are intermediate filament proteins constituting the nuclear lamina underneath the nuclear envelope thereby conferring proper shape and mechanical rigidity to the nucleus. Lamin proteins are also shown to be related diversely to basic nuclear processes. More than 400 mutations in human lamin A protein alone have been reported to produce at least 11 different disease conditions jointly termed as laminopathies. These mutations in lamin A are scattered throughout its helical rod domain, as well as the C-terminal domain containing the conserved Ig-fold region. The commonality of phenotypes in all these diseases is characterized by misshapen nuclei of the affected tissues which might stem from altered rigidity of the supporting lamina hence lamins. Here we have focused on autosomal dominant Emery-Dreifuss Muscular Dystrophy, one such laminopathy where R453W is the causative mutation located in the Ig domain of lamin A. We have investigated by single-molecule force spectroscopy how a stretching mechanical perturbation senses the destabilizing effect of the mutation in the lamin A Ig domain and compared the mechanoelastic properties of the mutant R453W with that of the wild-type in conjunction with steered molecular dynamics. Furthermore, we have shown the interaction of Ig domain with emerin, another key player and interacting partner in the pathogenesis of EDMD, is disrupted in the R453W mutant. This altered mechanoresistance of Ig domain itself and consequent uncoupling of lamin A-emerin interaction might underlie the altered mechanotransduction properties of EDMD affected nuclei.
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Affiliation(s)
- Manindra Bera
- Biophysics & Structural Genomics Division, Saha Institute of Nuclear Physics , 1/AF, Bidhannagar, Kolkata, West Bengal 700064, India
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Do lamin A and lamin C have unique roles? Chromosoma 2014; 124:1-12. [PMID: 25283634 DOI: 10.1007/s00412-014-0484-7] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2014] [Revised: 08/12/2014] [Accepted: 08/13/2014] [Indexed: 10/24/2022]
Abstract
The A-type lamins, lamin A and lamin C, generated from a single gene, LMNA, are major structural components of the nuclear lamina. The two alternative splice products have mostly been studied together because they have been considered to be interchangeable. However, several lines of evidence indicate that in spite of being generated from the same gene and having high similarities in their primary sequences, the two isoforms are not equivalent in different biological aspects in both health and disease. The key question is whether they have both overlapping and unique functions and whether they are distinctly regulated. Based on the so far available experimental evidence, lamin A appears to be the most regulated A-type isoform during development, aging, and disease which indicates that lamin A is implicated in many different biological aspects and may have a greater repertoire of specialized functions than lamin C. The aim of this review is to point out differences between the two major LMNA splice variants and the consequences of these differences on their functions. This may guide further research and be of prime importance for the understanding of the pathogenesis of LMNA mutations.
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50
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Guo Y, Kim Y, Shimi T, Goldman RD, Zheng Y. Concentration-dependent lamin assembly and its roles in the localization of other nuclear proteins. Mol Biol Cell 2014; 25:1287-97. [PMID: 24523288 PMCID: PMC3982994 DOI: 10.1091/mbc.e13-11-0644] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2013] [Revised: 02/05/2014] [Accepted: 02/06/2014] [Indexed: 11/11/2022] Open
Abstract
The nuclear lamina (NL) consists of lamin polymers and proteins that bind to the polymers. Disruption of NL proteins such as lamin and emerin leads to developmental defects and human diseases. However, the expression of multiple lamins, including lamin-A/C, lamin-B1, and lamin-B2, in mammals has made it difficult to study the assembly and function of the NL. Consequently, it has been unclear whether different lamins depend on one another for proper NL assembly and which NL functions are shared by all lamins or are specific to one lamin. Using mouse cells deleted of all or different combinations of lamins, we demonstrate that the assembly of each lamin into the NL depends primarily on the lamin concentration present in the nucleus. When expressed at sufficiently high levels, each lamin alone can assemble into an evenly organized NL, which is in turn sufficient to ensure the even distribution of the nuclear pore complexes. By contrast, only lamin-A can ensure the localization of emerin within the NL. Thus, when investigating the role of the NL in development and disease, it is critical to determine the protein levels of relevant lamins and the intricate shared or specific lamin functions in the tissue of interest.
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Affiliation(s)
- Yuxuan Guo
- Department of Biology, Johns Hopkins University, Baltimore, MD 21218
- Department of Embryology, Carnegie Institution for Science, Baltimore, MD 21218
| | - Youngjo Kim
- Department of Embryology, Carnegie Institution for Science, Baltimore, MD 21218
| | - Takeshi Shimi
- Department of Cell and Molecular Biology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611
| | - Robert D. Goldman
- Department of Cell and Molecular Biology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611
| | - Yixian Zheng
- Department of Biology, Johns Hopkins University, Baltimore, MD 21218
- Department of Embryology, Carnegie Institution for Science, Baltimore, MD 21218
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