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Perales IE, Jones SD, Piaszynski KM, Geyer PK. Developmental changes in nuclear lamina components during germ cell differentiation. Nucleus 2024; 15:2339214. [PMID: 38597409 PMCID: PMC11008544 DOI: 10.1080/19491034.2024.2339214] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2024] [Accepted: 04/02/2024] [Indexed: 04/11/2024] Open
Abstract
The nuclear lamina (NL) changes composition for regulation of nuclear events. We investigated changes that occur in Drosophila oogenesis, revealing switches in NL composition during germ cell differentiation. Germline stem cells (GSCs) express only LamB and predominantly emerin, whereas differentiating nurse cells predominantly express LamC and emerin2. A change in LamC-specific localization also occurs, wherein phosphorylated LamC redistributes to the nuclear interior only in the oocyte, prior to transcriptional reactivation of the meiotic genome. These changes support existing concepts that LamC promotes differentiation, a premise that was tested. Remarkably ectopic LamC production in GSCs did not promote premature differentiation. Increased LamC levels in differentiating germ cells altered internal nuclear structure, increased RNA production, and reduced female fertility due to defects in eggshell formation. These studies suggest differences between Drosophila lamins are regulatory, not functional, and reveal an unexpected robustness to level changes of a major scaffolding component of the NL.
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Affiliation(s)
- Isabella E. Perales
- Department of Biochemistry and Molecular Biology, University of Iowa, Iowa City, IA, USA
| | - Samuel D. Jones
- Department of Biochemistry and Molecular Biology, University of Iowa, Iowa City, IA, USA
| | | | - Pamela K. Geyer
- Department of Biochemistry and Molecular Biology, University of Iowa, Iowa City, IA, USA
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2
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Pujadas Liwag EM, Wei X, Acosta N, Carter LM, Yang J, Almassalha LM, Jain S, Daneshkhah A, Rao SSP, Seker-Polat F, MacQuarrie KL, Ibarra J, Agrawal V, Aiden EL, Kanemaki MT, Backman V, Adli M. Depletion of lamins B1 and B2 promotes chromatin mobility and induces differential gene expression by a mesoscale-motion-dependent mechanism. Genome Biol 2024; 25:77. [PMID: 38519987 PMCID: PMC10958841 DOI: 10.1186/s13059-024-03212-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2023] [Accepted: 03/07/2024] [Indexed: 03/25/2024] Open
Abstract
BACKGROUND B-type lamins are critical nuclear envelope proteins that interact with the three-dimensional genomic architecture. However, identifying the direct roles of B-lamins on dynamic genome organization has been challenging as their joint depletion severely impacts cell viability. To overcome this, we engineered mammalian cells to rapidly and completely degrade endogenous B-type lamins using Auxin-inducible degron technology. RESULTS Using live-cell Dual Partial Wave Spectroscopic (Dual-PWS) microscopy, Stochastic Optical Reconstruction Microscopy (STORM), in situ Hi-C, CRISPR-Sirius, and fluorescence in situ hybridization (FISH), we demonstrate that lamin B1 and lamin B2 are critical structural components of the nuclear periphery that create a repressive compartment for peripheral-associated genes. Lamin B1 and lamin B2 depletion minimally alters higher-order chromatin folding but disrupts cell morphology, significantly increases chromatin mobility, redistributes both constitutive and facultative heterochromatin, and induces differential gene expression both within and near lamin-associated domain (LAD) boundaries. Critically, we demonstrate that chromatin territories expand as upregulated genes within LADs radially shift inwards. Our results indicate that the mechanism of action of B-type lamins comes from their role in constraining chromatin motion and spatial positioning of gene-specific loci, heterochromatin, and chromatin domains. CONCLUSIONS Our findings suggest that, while B-type lamin degradation does not significantly change genome topology, it has major implications for three-dimensional chromatin conformation at the single-cell level both at the lamina-associated periphery and the non-LAD-associated nuclear interior with concomitant genome-wide transcriptional changes. This raises intriguing questions about the individual and overlapping roles of lamin B1 and lamin B2 in cellular function and disease.
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Affiliation(s)
- Emily M Pujadas Liwag
- Department of Biomedical Engineering, Northwestern University, Evanston, IL, 60208, USA
- IBIS Interdisciplinary Biological Sciences Graduate Program, Northwestern University, Evanston, USA
- Center for Physical Genomics and Engineering, Northwestern University, Evanston, IL, 60208, USA
| | - Xiaolong Wei
- Department of Surgery, University of Virginia School of Medicine, Charlottesville, VA, 22903, USA
| | - Nicolas Acosta
- Department of Biomedical Engineering, Northwestern University, Evanston, IL, 60208, USA
- Center for Physical Genomics and Engineering, Northwestern University, Evanston, IL, 60208, USA
| | - Lucas M Carter
- Department of Biomedical Engineering, Northwestern University, Evanston, IL, 60208, USA
- IBIS Interdisciplinary Biological Sciences Graduate Program, Northwestern University, Evanston, USA
- Center for Physical Genomics and Engineering, Northwestern University, Evanston, IL, 60208, USA
| | - Jiekun Yang
- Computer Science and Artificial Intelligence Laboratory, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
- Broad Institute of MIT and Harvard, Cambridge, MA, 02142, USA
| | - Luay M Almassalha
- Department of Biomedical Engineering, Northwestern University, Evanston, IL, 60208, USA
- Center for Physical Genomics and Engineering, Northwestern University, Evanston, IL, 60208, USA
- Department of Gastroenterology and Hepatology, Northwestern Memorial Hospital, Chicago, IL, 60611, USA
| | - Surbhi Jain
- Department of Biomedical Engineering, Northwestern University, Evanston, IL, 60208, USA
- Center for Physical Genomics and Engineering, Northwestern University, Evanston, IL, 60208, USA
| | - Ali Daneshkhah
- Department of Biomedical Engineering, Northwestern University, Evanston, IL, 60208, USA
- Center for Physical Genomics and Engineering, Northwestern University, Evanston, IL, 60208, USA
| | - Suhas S P Rao
- The Center for Genome Architecture, Baylor College of Medicine, Houston, TX, 77030, USA
- School of Medicine, Stanford University, Stanford, CA, 94305, USA
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Fidan Seker-Polat
- Feinberg School of Medicine, Robert Lurie Comprehensive Cancer Center, Department of Obstetrics and Gynecology, Northwestern University, Chicago, IL, 60611, USA
| | - Kyle L MacQuarrie
- Feinberg School of Medicine, Robert Lurie Comprehensive Cancer Center, Department of Pediatrics, Northwestern University, Chicago, IL, 60611, USA
- Stanley Manne Children's Research Institute, Ann & Robert H. Lurie Children's Hospital of Chicago, Chicago, IL, USA
| | - Joe Ibarra
- Feinberg School of Medicine, Robert Lurie Comprehensive Cancer Center, Department of Pediatrics, Northwestern University, Chicago, IL, 60611, USA
- Stanley Manne Children's Research Institute, Ann & Robert H. Lurie Children's Hospital of Chicago, Chicago, IL, USA
| | - Vasundhara Agrawal
- Department of Biomedical Engineering, Northwestern University, Evanston, IL, 60208, USA
- Center for Physical Genomics and Engineering, Northwestern University, Evanston, IL, 60208, USA
| | - Erez Lieberman Aiden
- Broad Institute of MIT and Harvard, Cambridge, MA, 02142, USA
- The Center for Genome Architecture, Baylor College of Medicine, Houston, TX, 77030, USA
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, 77030, USA
- Center for Theoretical Biological Physics, Rice University, Houston, TX, 77030, USA
- Departments of Computer Science and Computational and Applied Mathematics, Rice University, Houston, TX, 77030, USA
| | - Masato T Kanemaki
- Department of Chromosome Science, National Institute of Genetics, Mishima, Shizuoka, 411-8540, Japan
- Graduate Institute for Advanced Studies, SOKENDAI, Mishima, Shizuoka, 411-8540, Japan
- Department of Biological Science, The University of Tokyo, Tokyo, 113-0033, Japan
| | - Vadim Backman
- Department of Biomedical Engineering, Northwestern University, Evanston, IL, 60208, USA.
- Center for Physical Genomics and Engineering, Northwestern University, Evanston, IL, 60208, USA.
| | - Mazhar Adli
- Feinberg School of Medicine, Robert Lurie Comprehensive Cancer Center, Department of Obstetrics and Gynecology, Northwestern University, Chicago, IL, 60611, USA.
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Li L, Zhang P. Elevation of LEM Domain Containing 1 Predicts Poor Prognosis of NSCLC Patients and Triggers Malignant Stemness and Invasion of NSCLC Cells by Stimulating PI3K/AKT Pathway. Curr Mol Med 2024; 24:366-378. [PMID: 36967459 DOI: 10.2174/1566524023666230324135330] [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: 06/28/2022] [Revised: 12/16/2022] [Accepted: 01/09/2023] [Indexed: 03/29/2023]
Abstract
BACKGROUND Non-small cell lung cancer (NSCLC) is a leading cause of cancer-related death globally. LEM domain containing 1 (LEMD1) function has been identified in several cancers but not in NSCLC. OBJECTIVE This study aimed to investigate the LEMD1 function in NSCLC. METHODS NSCLC tissues were obtained from 66 patients, and LEMD1 expressions were measured using quantitative real-time PCR, immunohistochemical assay, and Western blot. Overall survival of NSCLC patients was estimated by the Kaplan-Meier method. Meanwhile, LEMD1 function and mechanism were assessed using Cell Counting Kit-8, 5-Ethynyl-2'-deoxyuridine analysis, Transwell, Sphere formation assay, and flow cytometry. Furthermore, LEMD1 function in vivo was evaluated by establishing a xenograft tumor model, hematoxylin-eosin staining, and immunohistochemical assay. RESULTS LEMD1 was highly expressed in NSCLC tissues and was interrelated to tumor differentiation, TNM stage, and lymph node metastasis of patients. Overall survival of NSCLC patients with high LEMD1 was found to be lower than that of patients with low LEMD1. Functionally, interference with LEMD1 restrained NSCLC cell proliferation, invasion, and stemness characteristics. Mechanistically, LEMD1 facilitated the malignant phenotype of NSCLC, and 740 Y-P reversed this impact, prompting that LEMD1 aggravated NSCLC by activating PI3K/AKT pathway. Furthermore, LEMD1 knockdown hindered NSCLC proliferation in vivo. Conclusion: LEMD1 accelerated NSCLC cell proliferation, invasion, and stemness characteristics via activating PI3K/AKT pathway.
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Affiliation(s)
- Li Li
- Department of Cardiothoracic Surgery, The Second Affiliated Hospital of Chongqing Medical University, Chongqing, 402177, China
| | - Pei Zhang
- Department of Cardiothoracic Surgery, The Second Affiliated Hospital of Chongqing Medical University, Chongqing, 402177, China
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Emond-Fraser V, Larouche M, Kubiniok P, Bonneil É, Li J, Bourouh M, Frizzi L, Thibault P, Archambault V. Identification of PP2A-B55 targets uncovers regulation of emerin during nuclear envelope reassembly in Drosophila. Open Biol 2023; 13:230104. [PMID: 37463656 PMCID: PMC10353892 DOI: 10.1098/rsob.230104] [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: 04/18/2023] [Accepted: 06/21/2023] [Indexed: 07/20/2023] Open
Abstract
Mitotic exit requires the dephosphorylation of many proteins whose phosphorylation was needed for mitosis. Protein phosphatase 2A with its B55 regulatory subunit (PP2A-B55) promotes this transition. However, the events and substrates that it regulates are incompletely understood. We used proteomic approaches in Drosophila to identify proteins that interact with and are dephosphorylated by PP2A-B55. Among several candidates, we identified emerin (otefin in Drosophila). Emerin resides in the inner nuclear membrane and interacts with the DNA-binding protein barrier-to-autointegration factor (BAF) via a LEM domain. We found that the phosphorylation of emerin at Ser50 and Ser54 near its LEM domain negatively regulates its association with BAF, lamin and additional emerin in mitosis. We show that dephosphorylation of emerin at these sites by PP2A-B55 determines the timing of nuclear envelope reformation. Genetic experiments indicate that this regulation is required during embryonic development. Phosphoregulation of the emerin-BAF complex formation by PP2A-B55 appears as a key event of mitotic exit that is likely conserved across species.
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Affiliation(s)
- Virginie Emond-Fraser
- Institute for Research in Immunology and Cancer, Université de Montréal, Montréal, H3T 1J4, Quebec, Canada
- Département de biochimie et médecine moléculaire, Université de Montréal, Montréal, H3T 1J4, Quebec, Canada
| | - Myreille Larouche
- Institute for Research in Immunology and Cancer, Université de Montréal, Montréal, H3T 1J4, Quebec, Canada
- Département de biochimie et médecine moléculaire, Université de Montréal, Montréal, H3T 1J4, Quebec, Canada
| | - Peter Kubiniok
- Institute for Research in Immunology and Cancer, Université de Montréal, Montréal, H3T 1J4, Quebec, Canada
| | - Éric Bonneil
- Institute for Research in Immunology and Cancer, Université de Montréal, Montréal, H3T 1J4, Quebec, Canada
| | - Jingjing Li
- Institute for Research in Immunology and Cancer, Université de Montréal, Montréal, H3T 1J4, Quebec, Canada
| | - Mohammed Bourouh
- Institute for Research in Immunology and Cancer, Université de Montréal, Montréal, H3T 1J4, Quebec, Canada
| | - Laura Frizzi
- Institute for Research in Immunology and Cancer, Université de Montréal, Montréal, H3T 1J4, Quebec, Canada
- Département de biochimie et médecine moléculaire, Université de Montréal, Montréal, H3T 1J4, Quebec, Canada
| | - Pierre Thibault
- Institute for Research in Immunology and Cancer, Université de Montréal, Montréal, H3T 1J4, Quebec, Canada
- Département de chimie, Université de Montréal, Montréal, H3T 1J4, Quebec, Canada
| | - Vincent Archambault
- Institute for Research in Immunology and Cancer, Université de Montréal, Montréal, H3T 1J4, Quebec, Canada
- Département de biochimie et médecine moléculaire, Université de Montréal, Montréal, H3T 1J4, Quebec, Canada
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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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Kitzman SC, Duan T, Pufall MA, Geyer PK. Checkpoint activation drives global gene expression changes in Drosophila nuclear lamina mutants. G3 (BETHESDA, MD.) 2022; 12:6459172. [PMID: 34893833 PMCID: PMC9210273 DOI: 10.1093/g3journal/jkab408] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Accepted: 11/22/2021] [Indexed: 11/25/2022]
Abstract
The nuclear lamina (NL) lines the inner nuclear membrane. This extensive protein network organizes chromatin and contributes to the regulation of transcription, DNA replication, and repair. Lap2-emerin-MAN1 domain (LEM-D) proteins are key members of the NL, representing proteins that connect the NL to the genome through shared interactions with the chromatin-binding protein Barrier-to-Autointegration Factor (BAF). Functions of the LEM-D protein emerin and BAF are essential during Drosophila melanogaster oogenesis. Indeed, loss of either emerin or BAF blocks germ cell development and causes loss of germline stem cells, defects linked to the deformation of NL structure, and non-canonical activation of Checkpoint kinase 2 (Chk2). Here, we investigate the contributions of emerin and BAF to gene expression in the ovary. Profiling RNAs from emerin and baf mutant ovaries revealed that nearly all baf misregulated genes were shared with emerin mutants, defining a set of NL-regulated genes. Strikingly, loss of Chk2 restored the expression of most NL-regulated genes, identifying a large class of Chk2-dependent genes (CDGs). Nonetheless, some genes remained misexpressed upon Chk2 loss, identifying a smaller class of emerin-dependent genes (EDGs). Properties of EDGs suggest a shared role for emerin and BAF in the repression of developmental genes. Properties of CDGs demonstrate that Chk2 activation drives global misexpression of genes in the emerin and baf mutant backgrounds. Notably, CDGs were found upregulated in lamin-B mutant backgrounds. These observations predict that Chk2 activation might have a general role in gene expression changes found in NL-associated diseases, such as laminopathies.
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Affiliation(s)
| | - Tingting Duan
- Department of Biochemistry, University of Iowa, Iowa City, IA 52242, USA
| | - Miles A Pufall
- Department of Biochemistry, University of Iowa, Iowa City, IA 52242, USA
| | - Pamela K Geyer
- Department of Biochemistry, University of Iowa, Iowa City, IA 52242, USA
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Transfected plasmid DNA is incorporated into the nucleus via nuclear envelope reformation at telophase. Commun Biol 2022; 5:78. [PMID: 35058555 PMCID: PMC8776997 DOI: 10.1038/s42003-022-03021-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2021] [Accepted: 12/27/2021] [Indexed: 12/15/2022] Open
Abstract
AbstractDNA transfection is an important technology in life sciences, wherein nuclear entry of DNA is necessary to express exogenous DNA. Non-viral vectors and their transfection reagents are useful as safe transfection tools. However, they have no effect on the transfection of non-proliferating cells, the reason for which is not well understood. This study elucidates the mechanism through which transfected DNA enters the nucleus for gene expression. To monitor the behavior of transfected DNA, we introduce plasmid bearing lacO repeats and RFP-coding sequences into cells expressing GFP-LacI and observe plasmid behavior and RFP expression in living cells. RFP expression appears only after mitosis. Electron microscopy reveals that plasmids are wrapped with nuclear envelope (NE)‒like membranes or associated with chromosomes at telophase. The depletion of BAF, which is involved in NE reformation, delays plasmid RFP expression. These results suggest that transfected DNA is incorporated into the nucleus during NE reformation at telophase.
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Zada D, Sela Y, Matosevich N, Monsonego A, Lerer-Goldshtein T, Nir Y, Appelbaum L. Parp1 promotes sleep, which enhances DNA repair in neurons. Mol Cell 2021; 81:4979-4993.e7. [PMID: 34798058 PMCID: PMC8688325 DOI: 10.1016/j.molcel.2021.10.026] [Citation(s) in RCA: 39] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2021] [Revised: 10/18/2021] [Accepted: 10/26/2021] [Indexed: 10/19/2022]
Abstract
The characteristics of the sleep drivers and the mechanisms through which sleep relieves the cellular homeostatic pressure are unclear. In flies, zebrafish, mice, and humans, DNA damage levels increase during wakefulness and decrease during sleep. Here, we show that 6 h of consolidated sleep is sufficient to reduce DNA damage in the zebrafish dorsal pallium. Induction of DNA damage by neuronal activity and mutagens triggered sleep and DNA repair. The activity of the DNA damage response (DDR) proteins Rad52 and Ku80 increased during sleep, and chromosome dynamics enhanced Rad52 activity. The activity of the DDR initiator poly(ADP-ribose) polymerase 1 (Parp1) increased following sleep deprivation. In both larva zebrafish and adult mice, Parp1 promoted sleep. Inhibition of Parp1 activity reduced sleep-dependent chromosome dynamics and repair. These results demonstrate that DNA damage is a homeostatic driver for sleep, and Parp1 pathways can sense this cellular pressure and facilitate sleep and repair activity.
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Affiliation(s)
- David Zada
- The Faculty of Life Sciences and the Multidisciplinary Brain Research Center, Bar-Ilan University, Ramat-Gan 5290002, Israel
| | - Yaniv Sela
- Department of Physiology and Pharmacology, Sackler Faculty of Medicine, and Sagol School of Neuroscience, Tel Aviv University, Tel Aviv-Yafo 69978, Israel
| | - Noa Matosevich
- Department of Physiology and Pharmacology, Sackler Faculty of Medicine, and Sagol School of Neuroscience, Tel Aviv University, Tel Aviv-Yafo 69978, Israel
| | - Adir Monsonego
- The Faculty of Life Sciences and the Multidisciplinary Brain Research Center, Bar-Ilan University, Ramat-Gan 5290002, Israel
| | - Tali Lerer-Goldshtein
- The Faculty of Life Sciences and the Multidisciplinary Brain Research Center, Bar-Ilan University, Ramat-Gan 5290002, Israel
| | - Yuval Nir
- Department of Physiology and Pharmacology, Sackler Faculty of Medicine, and Sagol School of Neuroscience, Tel Aviv University, Tel Aviv-Yafo 69978, Israel
| | - Lior Appelbaum
- The Faculty of Life Sciences and the Multidisciplinary Brain Research Center, Bar-Ilan University, Ramat-Gan 5290002, Israel.
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9
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Using nuclear envelope mutations to explore age-related skeletal muscle weakness. Clin Sci (Lond) 2020; 134:2177-2187. [PMID: 32844998 PMCID: PMC7450176 DOI: 10.1042/cs20190066] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2020] [Revised: 08/04/2020] [Accepted: 08/17/2020] [Indexed: 12/19/2022]
Abstract
Skeletal muscle weakness is an important determinant of age-related declines in independence and quality of life but its causes remain unclear. Accelerated ageing syndromes such as Hutchinson-Gilford Progerin Syndrome, caused by mutations in genes encoding nuclear envelope proteins, have been extensively studied to aid our understanding of the normal biological ageing process. Like several other pathologies associated with genetic defects to nuclear envelope proteins including Emery-Dreifuss muscular dystrophy, Limb-Girdle muscular dystrophy and congenital muscular dystrophy, these disorders can lead to severe muscle dysfunction. Here, we first describe the structure and function of nuclear envelope proteins, and then review the mechanisms by which mutations in genes encoding nuclear envelope proteins induce premature ageing diseases and muscle pathologies. In doing so, we highlight the potential importance of such genes in processes leading to skeletal muscle weakness in old age.
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10
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Sureka R, Mishra R. Identification of Evolutionarily Conserved Nuclear Matrix Proteins and Their Prokaryotic Origins. J Proteome Res 2020; 20:518-530. [PMID: 33289389 DOI: 10.1021/acs.jproteome.0c00550] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Compared to prokaryotic cells, a typical eukaryotic cell is much more complex along with its endomembrane system and membrane-bound organelles. Although the endosymbiosis theories convincingly explain the evolution of membrane-bound organelles such as mitochondria and chloroplasts, very little is understood about the evolutionary origins of the nucleus, the defining feature of eukaryotes. Most studies on nuclear evolution have not been able to take into consideration the underlying structural framework of the nucleus, attributed to the nuclear matrix (NuMat), a ribonucleoproteinaceous structure. This can largely be attributed to the lack of annotation of its core components. Since NuMat has been shown to provide a structural platform for facilitating a variety of nuclear functions such as replication, transcription, and splicing, it is important to identify its protein components to better understand these processes. In this study, we address this issue using the developing embryos of Drosophila melanogaster and Danio rerio and identify 362 core NuMat proteins that are conserved between the two organisms. We further compare our results with publicly available Mus musculus NuMat dataset and Homo sapiens cellular localization dataset to define the core homologous NuMat proteins consisting of 252 proteins. We find that of them, 86 protein groups have originated from pre-existing proteins in prokaryotes. While 36 were conserved across all eukaryotic supergroups, 14 new proteins evolved before the evolution of the last eukaryotic common ancestor and together, these 50 proteins out of the 252 core conserved NuMat proteins are conserved across all eukaryotes, indicating their indispensable nature for nuclear function for over 1.5 billion years of eukaryotic history. Our analysis paves the way to understand the evolution of the complex internal nuclear architecture and its functions.
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Affiliation(s)
- Rahul Sureka
- Centre for Cellular and Molecular Biology, Uppal Road, Hyderabad 500007, India
| | - Rakesh Mishra
- Centre for Cellular and Molecular Biology, Uppal Road, Hyderabad 500007, India
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Human VAPome Analysis Reveals MOSPD1 and MOSPD3 as Membrane Contact Site Proteins Interacting with FFAT-Related FFNT Motifs. Cell Rep 2020; 33:108475. [DOI: 10.1016/j.celrep.2020.108475] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2020] [Revised: 10/05/2020] [Accepted: 11/12/2020] [Indexed: 12/21/2022] Open
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Richardson A, Zentz ZA, Chambers AE, Sandwith SN, Reisinger MA, Saunders DW, Tompkins JD, Riggs AD, Routh ED, Rubenstein EM, Smaldino MA, Vaughn JP, Haney RA, Smaldino PJ. G-Quadruplex Helicase DHX36/G4R1 Engages Nuclear Lamina Proteins in Quiescent Breast Cancer Cells. ACS OMEGA 2020; 5:24916-24926. [PMID: 33015511 PMCID: PMC7528498 DOI: 10.1021/acsomega.0c03723] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/04/2020] [Accepted: 08/21/2020] [Indexed: 06/11/2023]
Abstract
G-quadruplexes (G4s) are nucleic acid structures found enriched within gene regulatory sequences. G4s control fundamental cellular processes, including replication, transcription, and translation. Proto-oncogenes are enriched with G4 sequences, while tumor-suppressor genes are depleted, suggesting roles for G4s in cell survival and proliferation. Specialized helicases participate in G4-mediated gene regulation via enzymatic unwinding activity. One such enzyme, DHX36/G4R1, is the major G4-helicase and is a master regulator of G4-DNAs and mRNAs. G4-resolution promotes the expression of proproliferative genes; as such, DHX36/G4R1 promotes cell proliferation. Little is known about how DHX36/G4R1 itself is regulated in nondividing cells. We hypothesized that DHX36/G4R1 protein binding partners are altered when a cell transitions from a dividing to a quiescent state. We found that DHX36/G4R1 co-purifies with a distinct set of proteins under quiescent conditions, which may represent a novel complex that regulates DHX36/G4R1 during cell cycle transitions and have implications for development and cancer.
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Affiliation(s)
- Adam.
E. Richardson
- Department
of Biology, Ball State University, Muncie, Indiana 47306, United States
| | - Zachary. A. Zentz
- Department
of Biology, Ball State University, Muncie, Indiana 47306, United States
| | - Antonio E. Chambers
- Department
of Biology, Ball State University, Muncie, Indiana 47306, United States
| | - Siara N. Sandwith
- Department
of Biology, Ball State University, Muncie, Indiana 47306, United States
| | - Michael A. Reisinger
- Department
of Biology, Ball State University, Muncie, Indiana 47306, United States
| | - Destinee W. Saunders
- Department
of Biology, Ball State University, Muncie, Indiana 47306, United States
| | - Joshua D. Tompkins
- Department
of Diabetes Complications and Metabolism, City of Hope, Duarte, California 91010, United States
| | - Arthur D. Riggs
- Department
of Diabetes Complications and Metabolism, City of Hope, Duarte, California 91010, United States
| | - Eric D. Routh
- Lineberger
Comprehensive Cancer Center, University
of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, United States
| | - Eric M. Rubenstein
- Department
of Biology, Ball State University, Muncie, Indiana 47306, United States
| | - Melissa A. Smaldino
- Department
of Biology, Ball State University, Muncie, Indiana 47306, United States
| | - James P. Vaughn
- NanoMedica
LLC, Winston-Salem, North Carolina 27101, United States
| | - Robert A. Haney
- Department
of Biology, Ball State University, Muncie, Indiana 47306, United States
| | - Philip J. Smaldino
- Department
of Biology, Ball State University, Muncie, Indiana 47306, United States
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13
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Sears RM, Roux KJ. Diverse cellular functions of barrier-to-autointegration factor and its roles in disease. J Cell Sci 2020; 133:133/16/jcs246546. [PMID: 32817163 DOI: 10.1242/jcs.246546] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Barrier-to-autointegration factor (BAF; encoded by BANF1) is a small highly conserved, ubiquitous and self-associating protein that coordinates with numerous binding partners to accomplish several key cellular processes. By interacting with double-stranded DNA, histones and various other nuclear proteins, including those enriched at the nuclear envelope, BAF appears to be essential for replicating cells to protect the genome and enable cell division. Cellular processes, such as innate immunity, post-mitotic nuclear reformation, repair of interphase nuclear envelope rupture, genomic regulation, and the DNA damage and repair response have all been shown to depend on BAF. This Review focuses on the regulation of the numerous interactions of BAF, which underlie the mechanisms by which BAF accomplishes its essential cellular functions. We will also discuss how perturbation of BAF function may contribute to human disease.
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Affiliation(s)
- Rhiannon M Sears
- Enabling Technologies Group, Sanford Research, Sioux Falls, SD 57104, USA.,Basic Biomedical Sciences, Sanford School of Medicine, University of South Dakota, Vermillion, SD 57069, USA
| | - Kyle J Roux
- Enabling Technologies Group, Sanford Research, Sioux Falls, SD 57104, USA .,Department of Pediatrics, Sanford School of Medicine, University of South Dakota, Sioux Falls, SD 57069, USA
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14
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Nuclear Envelope Proteins Modulating the Heterochromatin Formation and Functions in Fission Yeast. Cells 2020; 9:cells9081908. [PMID: 32824370 PMCID: PMC7464478 DOI: 10.3390/cells9081908] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2020] [Revised: 08/14/2020] [Accepted: 08/15/2020] [Indexed: 12/16/2022] Open
Abstract
The nuclear envelope (NE) consists of the inner and outer nuclear membranes (INM and ONM), and the nuclear pore complex (NPC), which penetrates the double membrane. ONM continues with the endoplasmic reticulum (ER). INM and NPC can interact with chromatin to regulate the genetic activities of the chromosome. Studies in the fission yeast Schizosaccharomyces pombe have contributed to understanding the molecular mechanisms underlying heterochromatin formation by the RNAi-mediated and histone deacetylase machineries. Recent studies have demonstrated that NE proteins modulate heterochromatin formation and functions through interactions with heterochromatic regions, including the pericentromeric and the sub-telomeric regions. In this review, we first introduce the molecular mechanisms underlying the heterochromatin formation and functions in fission yeast, and then summarize the NE proteins that play a role in anchoring heterochromatic regions and in modulating heterochromatin formation and functions, highlighting roles for a conserved INM protein, Lem2.
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15
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Piccus R, Brayson D. The nuclear envelope: LINCing tissue mechanics to genome regulation in cardiac and skeletal muscle. Biol Lett 2020; 16:20200302. [PMID: 32634376 DOI: 10.1098/rsbl.2020.0302] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Regulation of the genome is viewed through the prism of gene expression, DNA replication and DNA repair as controlled through transcription, chromatin compartmentalisation and recruitment of repair factors by enzymes such as DNA polymerases, ligases, acetylases, methylases and cyclin-dependent kinases. However, recent advances in the field of muscle cell physiology have also shown a compelling role for 'outside-in' biophysical control of genomic material through mechanotransduction. The crucial hub that transduces these biophysical signals is called the Linker of Nucleoskeleton and Cytoskeleton (LINC). This complex is embedded across the nuclear envelope, which separates the nucleus from the cytoplasm. How the LINC complex operates to mechanically regulate the many functions of DNA is becoming increasingly clear, and recent advances have provided exciting insight into how this occurs in cells from mechanically activated tissues such as skeletal and cardiac muscle. Nevertheless, there are still some notable shortcomings in our understanding of these processes and resolving these will likely help us understand how muscle diseases manifest at the level of the genome.
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Affiliation(s)
- Rachel Piccus
- Centre for Human and Applied Physiological Sciences, King's College London, London SE1 1UL, UK
| | - Daniel Brayson
- School of Cardiovascular Medicine and Sciences, King's College London, London SE5 9NU, UK.,Molecular Neurosciences, UCL Great Ormond Street Institute of Child Health, 30 Guilford Street, London WC1N 1EH, UK
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16
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Moser B, Basílio J, Gotzmann J, Brachner A, Foisner R. Comparative Interactome Analysis of Emerin, MAN1 and LEM2 Reveals a Unique Role for LEM2 in Nucleotide Excision Repair. Cells 2020; 9:cells9020463. [PMID: 32085595 PMCID: PMC7072835 DOI: 10.3390/cells9020463] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2019] [Revised: 02/06/2020] [Accepted: 02/11/2020] [Indexed: 12/19/2022] Open
Abstract
LAP2-Emerin-MAN1 (LEM) domain-containing proteins represent an abundant group of inner nuclear membrane proteins involved in diverse nuclear functions, but their functional redundancies remain unclear. Here, using the biotinylation-dependent proximity approach, we report proteome-wide comparative interactome analysis of the two structurally related LEM proteins MAN1 (LEMD3) and LEM2 (LEMD2), and the more distantly related emerin (EMD). While over 60% of the relatively small group of MAN1 and emerin interactors were also found in the LEM2 interactome, the latter included a large number of candidates (>85%) unique for LEM2. The interacting partners unique for emerin support and provide further insight into the previously reported role of emerin in centrosome positioning, and the MAN1-specific interactors suggest a role of MAN1 in ribonucleoprotein complex assembly. Interestingly, the LEM2-specific interactome contained several proteins of the nucleotide excision repair pathway. Accordingly, LEM2-depleted cells, but not MAN1- and emerin-depleted cells, showed impaired proliferation following ultraviolet-C (UV-C) irradiation and prolonged accumulation of γH2AX, similar to cells deficient in the nucleotide excision repair protein DNA damage-binding protein 1 (DDB1). These findings indicate impaired DNA damage repair in LEM2-depleted cells. Overall, this interactome study identifies new potential interaction partners of emerin, MAN1 and particularly LEM2, and describes a novel potential involvement of LEM2 in nucleotide excision repair at the nuclear periphery.
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Affiliation(s)
- Bernhard Moser
- Max Perutz Labs, Center of Medical Biochemistry, Medical University of Vienna, Vienna Biocenter (VBC), 1030 Vienna, Austria; (B.M.); (J.G.)
- Department of Vascular Biology and Thrombosis Research, Center for Physiology and Pharmacology, Medical University of Vienna, 1090 Vienna, Austria
| | - José Basílio
- Department of Vascular Biology and Thrombosis Research, Center for Physiology and Pharmacology, Medical University of Vienna, 1090 Vienna, Austria
| | - Josef Gotzmann
- Max Perutz Labs, Center of Medical Biochemistry, Medical University of Vienna, Vienna Biocenter (VBC), 1030 Vienna, Austria; (B.M.); (J.G.)
| | - Andreas Brachner
- Max Perutz Labs, Center of Medical Biochemistry, Medical University of Vienna, Vienna Biocenter (VBC), 1030 Vienna, Austria; (B.M.); (J.G.)
- Correspondence: (A.B.); (R.F.)
| | - Roland Foisner
- Max Perutz Labs, Center of Medical Biochemistry, Medical University of Vienna, Vienna Biocenter (VBC), 1030 Vienna, Austria; (B.M.); (J.G.)
- Correspondence: (A.B.); (R.F.)
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17
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Miyazono KI, Ohno Y, Wada H, Ito T, Fukatsu Y, Kurisaki A, Asashima M, Tanokura M. Structural basis for receptor-regulated SMAD recognition by MAN1. Nucleic Acids Res 2019; 46:12139-12153. [PMID: 30321401 PMCID: PMC6294489 DOI: 10.1093/nar/gky925] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2018] [Accepted: 10/04/2018] [Indexed: 01/15/2023] Open
Abstract
Receptor-regulated SMAD (R-SMAD: SMAD1, SMAD2, SMAD3, SMAD5 and SMAD8) proteins are key transcription factors of the transforming growth factor-β (TGF-β) superfamily of cytokines. MAN1, an integral protein of the inner nuclear membrane, is a SMAD cofactor that terminates TGF-β superfamily signals. Heterozygous loss-of-function mutations in MAN1 result in osteopoikilosis, Buschke-Ollendorff syndrome and melorheostosis. MAN1 interacts with MAD homology 2 (MH2) domains of R-SMAD proteins using its C-terminal U2AF homology motif (UHM) domain and UHM ligand motif (ULM) and facilitates R-SMAD dephosphorylation. Here, we report the structural basis for R-SMAD recognition by MAN1. The SMAD2–MAN1 and SMAD1–MAN1 complex structures show that an intramolecular UHM–ULM interaction of MAN1 forms a hydrophobic surface that interacts with a hydrophobic surface among the H2 helix, the strands β8 and β9, and the L3 loop of the MH2 domains of R-SMAD proteins. The complex structures also show the mechanism by which SMAD cofactors distinguish R-SMAD proteins that possess a highly conserved molecular surface.
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Affiliation(s)
- Ken-Ichi Miyazono
- Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo 113-8657, Japan
| | - Yosuke Ohno
- Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo 113-8657, Japan
| | - Hikaru Wada
- Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo 113-8657, Japan
| | - Tomoko Ito
- Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo 113-8657, Japan
| | - Yui Fukatsu
- Graduate School of Biological Sciences, Nara Institute of Science and Technology, Nara, Japan
| | - Akira Kurisaki
- Graduate School of Biological Sciences, Nara Institute of Science and Technology, Nara, Japan.,Biotechnology Research Institute for Drug Discovery (BRD), National Institute of Advanced Industrial Science and Technology (AIST), Ibaraki, Japan
| | - Makoto Asashima
- Biotechnology Research Institute for Drug Discovery (BRD), National Institute of Advanced Industrial Science and Technology (AIST), Ibaraki, Japan
| | - Masaru Tanokura
- Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo 113-8657, Japan
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18
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Liu C, Yu H, Shen X, Qiao J, Wu X, Chang J, Zhu X, Wang J, Shen X. Prognostic significance and biological function of Lamina-associated polypeptide 2 in non-small-cell lung cancer. Onco Targets Ther 2019; 12:3817-3827. [PMID: 31190881 PMCID: PMC6529027 DOI: 10.2147/ott.s179870] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2018] [Accepted: 04/26/2019] [Indexed: 01/24/2023] Open
Abstract
Purpose: Lamina-associated polypeptide 2 (LAP2; encoded by TMPO), is a nuclear protein that may affect chromatin regulation and gene expression through dynamically binding to nuclear lamin. TMPO (LAP2) plays dual roles of either suppressing or promoting proliferation of cells, depending on the status of the cell. It has been reported that TMPO is up-regulated in various cancer types. However, its function in lung cancer has not been studied yet. Materials and methods: A series of clinical microarray datasets for lung cancer were investigated to demonstrate the expression of TMPO. The transcription of TMPO gene in human lung cancer was analyzed using Oncomine platform (www.oncomine.org) according to the standardized procedures described previously. Four separate datasets (Hou Lung, Okayama Lung, Beer Lung, and Garber Lung) were analyzed. Results: Here, we show that TMPO is over-expressed in lung cancer tissues, and that a high level of TMPO indicates a poor prognosis in lung cancer patients. Knockdown of TMPO in lung cancer cells inhibits cell proliferation and induces apoptosis. Also, down-regulation of TMPO leads to an impaired metastatic ability of tumor cells. A nude mice tumor model show that knockdown of TMPO suppresses tumor formation in vivo. Conclusion: Collectively, this study suggests TMPO as an oncogene and a novel prognostic gene in lung cancer.
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Affiliation(s)
- Chang Liu
- Department of Medical Oncology, Fudan University Shanghai Cancer Center, Shanghai 200032, People's Republic of China.,Department of Oncology, Shanghai Medical College, Fudan University, Shanghai 200032, People's Republic of China
| | - Hui Yu
- Department of Medical Oncology, Fudan University Shanghai Cancer Center, Shanghai 200032, People's Republic of China.,Department of Oncology, Shanghai Medical College, Fudan University, Shanghai 200032, People's Republic of China
| | - Xuxia Shen
- Department of Oncology, Shanghai Medical College, Fudan University, Shanghai 200032, People's Republic of China.,Department of Pathology, Fudan University Shanghai Cancer Center, Shanghai 200032, People's Republic of China
| | - Jie Qiao
- Department of Medical Oncology, Fudan University Shanghai Cancer Center, Shanghai 200032, People's Republic of China.,Department of Oncology, Shanghai Medical College, Fudan University, Shanghai 200032, People's Republic of China
| | - Xianghua Wu
- Department of Medical Oncology, Fudan University Shanghai Cancer Center, Shanghai 200032, People's Republic of China.,Department of Oncology, Shanghai Medical College, Fudan University, Shanghai 200032, People's Republic of China
| | - Jianhua Chang
- Department of Medical Oncology, Fudan University Shanghai Cancer Center, Shanghai 200032, People's Republic of China.,Department of Oncology, Shanghai Medical College, Fudan University, Shanghai 200032, People's Republic of China
| | - Xunxia Zhu
- Department of Thoracic Surgery, The Affiliated Huadong Hospital of Fudan University, Shanghai 200040, People's Republic of China
| | - Jialei Wang
- Department of Medical Oncology, Fudan University Shanghai Cancer Center, Shanghai 200032, People's Republic of China.,Department of Oncology, Shanghai Medical College, Fudan University, Shanghai 200032, People's Republic of China
| | - Xiaoyong Shen
- Department of Thoracic Surgery, The Affiliated Huadong Hospital of Fudan University, Shanghai 200040, People's Republic of China
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19
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Kinugasa Y, Hirano Y, Sawai M, Ohno Y, Shindo T, Asakawa H, Chikashige Y, Shibata S, Kihara A, Haraguchi T, Hiraoka Y. The very-long-chain fatty acid elongase Elo2 rescues lethal defects associated with loss of the nuclear barrier function in fission yeast cells. J Cell Sci 2019; 132:jcs.229021. [PMID: 30975915 DOI: 10.1242/jcs.229021] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2018] [Accepted: 04/03/2019] [Indexed: 12/21/2022] Open
Abstract
In eukaryotic cells, chromosomes are confined to the nucleus, which is compartmentalized by the nuclear membranes; these are continuous with the endoplasmic reticulum membranes. Maintaining the homeostasis of these membranes is an important cellular activity performed by lipid metabolic enzymes. However, how lipid metabolic enzymes affect nuclear membrane functions remains to be elucidated. We found that the very-long-chain fatty acid elongase Elo2 is located in the nuclear membrane and prevents lethal defects associated with nuclear membrane ruptures in mutants of the nuclear membrane proteins Lem2 and Bqt4 in the fission yeast Schizosaccharomyces pombe. Lipid composition analysis shows that t20:0/24:0 phytoceramide (a conjugate of C20:0 phytosphingosine and C24:0 fatty acid) is a major ceramide species in S. pombe The quantity of this ceramide is reduced in the absence of Lem2, and restored by increased expression of Elo2. Furthermore, loss of S. pombe Elo2 can be rescued by its human orthologs. These results suggest that the conserved very-long-chain fatty acid elongase producing the ceramide component is essential for nuclear membrane integrity and cell viability in eukaryotes.This article has an associated First Person interview with the first author of the paper.
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Affiliation(s)
- Yasuha Kinugasa
- Graduate School of Frontier Biosciences, Osaka University, Suita 565-0871, Japan
| | - Yasuhiro Hirano
- Graduate School of Frontier Biosciences, Osaka University, Suita 565-0871, Japan
| | - Megumi Sawai
- Faculty of Pharmaceutical Sciences, Hokkaido University, Sapporo 060-0812, Japan
| | - Yusuke Ohno
- Faculty of Pharmaceutical Sciences, Hokkaido University, Sapporo 060-0812, Japan
| | - Tomoko Shindo
- Electron Microscope Laboratory, Keio University School of Medicine, Shinjuku-ku, Tokyo 160-8582, Japan
| | - Haruhiko Asakawa
- Graduate School of Frontier Biosciences, Osaka University, Suita 565-0871, Japan
| | - Yuji Chikashige
- Advanced ICT Research Institute Kobe, National Institute of Information and Communications Technology, Kobe 651-2492, Japan
| | - Shinsuke Shibata
- Electron Microscope Laboratory, Keio University School of Medicine, Shinjuku-ku, Tokyo 160-8582, Japan
| | - Akio Kihara
- Faculty of Pharmaceutical Sciences, Hokkaido University, Sapporo 060-0812, Japan
| | - Tokuko Haraguchi
- Graduate School of Frontier Biosciences, Osaka University, Suita 565-0871, Japan.,Advanced ICT Research Institute Kobe, National Institute of Information and Communications Technology, Kobe 651-2492, Japan
| | - Yasushi Hiraoka
- Graduate School of Frontier Biosciences, Osaka University, Suita 565-0871, Japan .,Advanced ICT Research Institute Kobe, National Institute of Information and Communications Technology, Kobe 651-2492, Japan
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20
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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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21
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Pereira CD, Serrano JB, Martins F, da Cruz E Silva OAB, Rebelo S. Nuclear envelope dynamics during mammalian spermatogenesis: new insights on male fertility. Biol Rev Camb Philos Soc 2019; 94:1195-1219. [PMID: 30701647 DOI: 10.1111/brv.12498] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2018] [Revised: 01/04/2019] [Accepted: 01/08/2019] [Indexed: 02/06/2023]
Abstract
The production of highly specialized spermatozoa from undifferentiated spermatogonia is a strictly organized and programmed process requiring extensive restructuring of the entire cell. One of the most remarkable cellular transformations accompanying the various phases of spermatogenesis is the profound remodelling of the nuclear architecture, in which the nuclear envelope (NE) seems to be crucially involved. In recent years, several proteins from the distinct layers forming the NE (i.e. the inner and outer nuclear membranes as well as the nuclear lamina) have been associated with meiosis and/or spermiogenesis in different mammalian species. Among these are A- and B-type lamins, Dpy-19-like protein 2 (DPY19L2), lamin B receptor (LBR), lamina-associated polypeptide 1 (LAP1), LAP2/emerin/MAN1 (LEM) domain-containing proteins, spermatogenesis-associated 46 (SPATA46) and diverse elements of the linker of nucleoskeleton and cytoskeleton (LINC) complex, namely Sad-1/UNC-84 homology (SUN) and Klarsicht/ANC-1/Syne-1 homology (KASH) domain-containing proteins. Herein, we summarize the current state of the art on the cellular and subcellular distribution of NE proteins expressed during mammalian spermatogenesis, and discuss the latest research developments regarding their testis-specific functions. This review provides a comprehensive and innovative overview of the NE network as a regulatory platform and as an essential determinant of efficient meiotic chromosome recombination as well as spermiogenesis-associated nuclear remodelling and differentiation in mammalian male germline cells. Thus, this review provides important novel insights on the biological relevance of NE proteins for male fertility.
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Affiliation(s)
- Cátia D Pereira
- Department of Medical Sciences, Neuroscience and Signalling Laboratory, Institute for Biomedicine (iBiMED), University of Aveiro, 3810-193 Aveiro, Portugal
| | - Joana B Serrano
- Department of Medical Sciences, Neuroscience and Signalling Laboratory, Institute for Biomedicine (iBiMED), University of Aveiro, 3810-193 Aveiro, Portugal
| | - Filipa Martins
- Department of Medical Sciences, Neuroscience and Signalling Laboratory, Institute for Biomedicine (iBiMED), University of Aveiro, 3810-193 Aveiro, Portugal
| | - Odete A B da Cruz E Silva
- Department of Medical Sciences, Neuroscience and Signalling Laboratory, Institute for Biomedicine (iBiMED), University of Aveiro, 3810-193 Aveiro, Portugal.,The Discovery CTR, University of Aveiro Campus, 3810-193 Aveiro, Portugal
| | - Sandra Rebelo
- Department of Medical Sciences, Neuroscience and Signalling Laboratory, Institute for Biomedicine (iBiMED), University of Aveiro, 3810-193 Aveiro, Portugal
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22
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Iwamoto M, Fukuda Y, Osakada H, Mori C, Hiraoka Y, Haraguchi T. Identification of the evolutionarily conserved nuclear envelope proteins Lem2 and MicLem2 in Tetrahymena thermophila. Gene 2019; 721S:100006. [PMID: 32550543 PMCID: PMC7285967 DOI: 10.1016/j.gene.2019.100006] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2018] [Revised: 12/18/2018] [Accepted: 01/11/2019] [Indexed: 11/26/2022]
Abstract
Lem2 family proteins, i.e. the LAP2-Emerin-MAN1 (LEM) domain-containing nuclear envelope proteins, are well-conserved from yeasts to humans, both of which belong to the Opisthokonta supergroup. However, whether their homologs are present in other eukaryotic phylogenies remains unclear. In this study, we identified two Lem2 homolog proteins, which we named as Lem2 and MicLem2, in a ciliate Tetrahymena thermophila belonging to the SAR supergroup. Lem2 was localized to the nuclear envelope of the macronucleus (MAC) and micronucleus (MIC), while MicLem2 was exclusively localized to the nuclear envelope of the MIC. Immunoelectron microscopy revealed that Lem2 in T. thermophila was localized to both the inner and outer nuclear envelopes of the MAC and MIC, while MicLem2 was mostly localized to the nuclear pores of the MIC. Molecular domain analysis using GFP-fused protein showed that the N-terminal and luminal domains, including the transmembrane segments, are responsible for nuclear envelope localization. During sexual reproduction, enrichment of Lem2 occurred in the nuclear envelopes of the MAC and MIC to be degraded, while MicLem2 was enriched in the nuclear envelope of the MIC that escaped degradation. These findings suggest the unique characteristics of Tetrahymena Lem2 proteins. Our findings provide insight into the evolutionary divergence of nuclear envelope proteins. Conserved nuclear envelope proteins Lem2 and MicLem2 are identified in Tetrahymena. Lem2 is localized to the nuclear envelope of the macronucleus and the micronucleus. MicLem2 is localized to the nuclear pore complex of the micronucleus. In sexual reproduction, Lem2 is enriched to the nuclei assigned to degradation. MicLem2 is enriched to the micronuclei that are escaped from degradation.
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Key Words
- BAF, barrier-to-autointegration factor
- DAPI, 4′,6‑diamidino‑2‑phenylindole
- DDW, double distilled water
- EDTA, ethylenediaminetetraacetic acid
- ER, endoplasmic reticulum
- GA, glutaraldehyde
- HeH domain
- HeH, helix-extension-helix
- LAP2, lamina associated polypeptide 2
- LEM domain
- LEM, LAP2-Emerin-MAN1
- MAC, macronucleus
- MIC, micronucleus
- MSC domain
- MSC, Man1-Src1p-C-terminal
- Man1
- Man1-Src1p-C-terminal domain
- NE, nuclear envelope
- NLS, nuclear localization signal
- NPC, nuclear pore complex
- Nuclear dimorphism
- Nuclear envelope
- ONM and INM, outer and inner nuclear membranes
- PB, phosphate buffer
- PBS, phosphate buffered saline
- Protist
- RRM, RNA recognition motif
- TM, transmembrane
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Affiliation(s)
- Masaaki Iwamoto
- Advanced ICT Research Institute Kobe, National Institute of Information and Communications Technology, Kobe 651-2492, Japan
| | - Yasuhiro Fukuda
- Graduate School of Agricultural Science, Tohoku University, Osaki, 989-6711, Japan
| | - Hiroko Osakada
- Advanced ICT Research Institute Kobe, National Institute of Information and Communications Technology, Kobe 651-2492, Japan
| | - Chie Mori
- Advanced ICT Research Institute Kobe, National Institute of Information and Communications Technology, Kobe 651-2492, Japan
| | - Yasushi Hiraoka
- Advanced ICT Research Institute Kobe, National Institute of Information and Communications Technology, Kobe 651-2492, Japan.,Graduate School of Frontier Biosciences, Osaka University, Suita 565-0871, Japan
| | - Tokuko Haraguchi
- Advanced ICT Research Institute Kobe, National Institute of Information and Communications Technology, Kobe 651-2492, Japan.,Graduate School of Frontier Biosciences, Osaka University, Suita 565-0871, Japan
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23
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Pałka M, Tomczak A, Grabowska K, Machowska M, Piekarowicz K, Rzepecka D, Rzepecki R. Laminopathies: what can humans learn from fruit flies. Cell Mol Biol Lett 2018; 23:32. [PMID: 30002683 PMCID: PMC6034310 DOI: 10.1186/s11658-018-0093-1] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2018] [Accepted: 06/05/2018] [Indexed: 01/01/2023] Open
Abstract
Lamin proteins are type V intermediate filament proteins (IFs) located inside the cell nucleus. They are evolutionarily conserved and have similar domain organization and properties to cytoplasmic IFs. Lamins provide a skeletal network for chromatin, the nuclear envelope, nuclear pore complexes and the entire nucleus. They are also responsible for proper connections between the karyoskeleton and structural elements in the cytoplasm: actin and the microtubule and cytoplasmic IF networks. Lamins affect transcription and splicing either directly or indirectly. Translocation of active genes into the close proximity of nuclear lamina is thought to result in their transcriptional silencing. Mutations in genes coding for lamins and interacting proteins in humans result in various genetic disorders, called laminopathies. Human genes coding for A-type lamin (LMNA) are the most frequently mutated. The resulting phenotypes include muscle, cardiac, neuronal, lipodystrophic and metabolic pathologies, early aging phenotypes, and combined complex phenotypes. The Drosophila melanogaster genome codes for lamin B-type (lamin Dm), lamin A-type (lamin C), and for LEM-domain proteins, BAF, LINC-complex proteins and all typical nuclear proteins. The fruit fly system is simpler than the vertebrate one since in flies there is only single lamin B-type and single lamin A-type protein, as opposed to the complex system of B- and A-type lamins in Danio, Xenopus and Mus musculus. This offers a unique opportunity to study laminopathies. Applying genetic tools based on Gal4 and in vitro nuclear assembly system to the fruit fly model may successfully advance knowledge of laminopathies. Here, we review studies of the laminopathies in the fly model system.
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Affiliation(s)
- Marta Pałka
- Laboratory of Nuclear Proteins, Faculty of Biotechnology, University of Wroclaw, Fryderyka Joliot-Curie 14a, 50-383 Wroclaw, Poland
| | - Aleksandra Tomczak
- Laboratory of Nuclear Proteins, Faculty of Biotechnology, University of Wroclaw, Fryderyka Joliot-Curie 14a, 50-383 Wroclaw, Poland
| | - Katarzyna Grabowska
- Laboratory of Nuclear Proteins, Faculty of Biotechnology, University of Wroclaw, Fryderyka Joliot-Curie 14a, 50-383 Wroclaw, Poland
| | - Magdalena Machowska
- Laboratory of Nuclear Proteins, Faculty of Biotechnology, University of Wroclaw, Fryderyka Joliot-Curie 14a, 50-383 Wroclaw, Poland
| | - Katarzyna Piekarowicz
- Laboratory of Nuclear Proteins, Faculty of Biotechnology, University of Wroclaw, Fryderyka Joliot-Curie 14a, 50-383 Wroclaw, Poland
| | - Dorota Rzepecka
- Laboratory of Nuclear Proteins, Faculty of Biotechnology, University of Wroclaw, Fryderyka Joliot-Curie 14a, 50-383 Wroclaw, Poland
| | - Ryszard Rzepecki
- Laboratory of Nuclear Proteins, Faculty of Biotechnology, University of Wroclaw, Fryderyka Joliot-Curie 14a, 50-383 Wroclaw, Poland
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24
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Linker of nucleoskeleton and cytoskeleton complex proteins in cardiomyopathy. Biophys Rev 2018; 10:1033-1051. [PMID: 29869195 PMCID: PMC6082319 DOI: 10.1007/s12551-018-0431-6] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2018] [Accepted: 05/24/2018] [Indexed: 12/21/2022] Open
Abstract
The linker of nucleoskeleton and cytoskeleton (LINC) complex couples the nuclear lamina to the cytoskeleton. The LINC complex and its associated proteins play diverse roles in cells, ranging from genome organization, nuclear morphology, gene expression, to mechanical stability. The importance of a functional LINC complex is highlighted by the large number of mutations in genes encoding LINC complex proteins that lead to skeletal and cardiac myopathies. In this review, the structure, function, and interactions between components of the LINC complex will be described. Mutations that are known to cause cardiomyopathy in patients will be discussed alongside their respective mouse models. Furthermore, future challenges for the field and emerging technologies to investigate LINC complex function will be discussed.
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25
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Lukášová E, Kovařík A, Kozubek S. Consequences of Lamin B1 and Lamin B Receptor Downregulation in Senescence. Cells 2018; 7:cells7020011. [PMID: 29415520 PMCID: PMC5850099 DOI: 10.3390/cells7020011] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2017] [Revised: 01/24/2018] [Accepted: 01/31/2018] [Indexed: 01/28/2023] Open
Abstract
Anchoring of heterochromatin to the nuclear envelope appears to be an important process ensuring the spatial organization of the chromatin structure and genome function in eukaryotic nuclei. Proteins of the inner nuclear membrane (INM) mediating these interactions are able to recognize lamina-associated heterochromatin domains (termed LAD) and simultaneously bind either lamin A/C or lamin B1. One of these proteins is the lamin B receptor (LBR) that binds lamin B1 and tethers heterochromatin to the INM in embryonic and undifferentiated cells. It is replaced by lamin A/C with specific lamin A/C binding proteins at the beginning of cell differentiation and in differentiated cells. Our functional experiments in cancer cell lines show that heterochromatin in cancer cells is tethered to the INM by LBR, which is downregulated together with lamin B1 at the onset of cell transition to senescence. The downregulation of these proteins in senescent cells leads to the detachment of centromeric repetitive sequences from INM, their relocation to the nucleoplasm, and distension. In cells, the expression of LBR and LB1 is highly coordinated as evidenced by the reduction of both proteins in LBR shRNA lines. The loss of the constitutive heterochromatin structure containing LADs results in changes in chromatin architecture and genome function and can be the reason for the permanent loss of cell proliferation in senescence.
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Affiliation(s)
- Emilie Lukášová
- Department of Cell Biology and Radiobiology, Institute of Biophysics, Czech Academy of Sciences, Královopolská 135, Brno 61265, Czech Republic.
- Department of Molecular Epigenetics, Institute of Biophysics, Czech Academy of Sciences, Královopolská 135, Brno 61265, Czech Republic.
| | - Aleš Kovařík
- Department of Molecular Epigenetics, Institute of Biophysics, Czech Academy of Sciences, Královopolská 135, Brno 61265, Czech Republic.
| | - Stanislav Kozubek
- Department of Cell Biology and Radiobiology, Institute of Biophysics, Czech Academy of Sciences, Královopolská 135, Brno 61265, Czech Republic.
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26
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Hirano Y, Kinugasa Y, Asakawa H, Chikashige Y, Obuse C, Haraguchi T, Hiraoka Y. Lem2 is retained at the nuclear envelope through its interaction with Bqt4 in fission yeast. Genes Cells 2018; 23:122-135. [PMID: 29292846 DOI: 10.1111/gtc.12557] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2017] [Accepted: 12/04/2017] [Indexed: 12/31/2022]
Abstract
Inner nuclear membrane (INM) proteins are thought to play important roles in modulating nuclear organization and function through their interactions with chromatin. However, these INM proteins share redundant functions in metazoans that pose difficulties for functional studies. The fission yeast Schizosaccharomyces pombe exhibits a relatively small number of INM proteins, and molecular genetic tools are available to separate their redundant functions. In S. pombe, it has been reported that among potentially redundant INM proteins, Lem2 displays a unique genetic interaction with another INM protein, Bqt4, which is involved in anchoring telomeres to the nuclear envelope. Double mutations in the lem2 and bqt4 genes confer synthetic lethality during vegetative growth. Here, we show that Lem2 is retained at the nuclear envelope through its interaction with Bqt4, as the loss of Bqt4 results in the exclusive accumulation of Lem2 to the spindle pole body (SPB). An N-terminal nucleoplasmic region of Lem2 bears affinity to both Bqt4 and the SPB in a competitive manner. In contrast, the synthetic lethality of the lem2 bqt4 double mutant is suppressed by the C-terminal region of Lem2. These results indicate that the N-terminal and C-terminal domains of Lem2 show independent functions with respect to Bqt4.
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Affiliation(s)
- Yasuhiro Hirano
- Graduate School of Frontier Biosciences, Osaka University, Suita, Japan
| | - Yasuha Kinugasa
- Graduate School of Frontier Biosciences, Osaka University, Suita, Japan
| | - Haruhiko Asakawa
- Graduate School of Frontier Biosciences, Osaka University, Suita, Japan
| | - Yuji Chikashige
- Advanced ICT Research Institute Kobe, National Institute of Information and Communications Technology, Kobe, Japan
| | - Chikashi Obuse
- Department of Biological Sciences, Graduate School of Science, Osaka University, Toyonaka, Osaka, Japan.,Graduate School of Life Science, Hokkaido University, Sapporo, Japan
| | - Tokuko Haraguchi
- Graduate School of Frontier Biosciences, Osaka University, Suita, Japan.,Advanced ICT Research Institute Kobe, National Institute of Information and Communications Technology, Kobe, Japan
| | - Yasushi Hiraoka
- Graduate School of Frontier Biosciences, Osaka University, Suita, Japan.,Advanced ICT Research Institute Kobe, National Institute of Information and Communications Technology, Kobe, Japan
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27
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Abstract
Biological cells sample their surrounding microenvironments using nanoscale force sensors on the cell surfaces. These surface-based force and stress sensors generate physical and chemical responses inside the cell. The inherently well-connected cytoskeleton and its physical contacts with the force elements on the nuclear membrane lead these physicochemical responses to cascade all the way inside the cell nucleus, physically altering the nuclear state. These physical alterations of the cell nucleus, through yet-unknown complex steps elicit physical and functional response from the chromatin in the form of altered gene expression profiles. This mechanism of force/stress sensing by the cell and then its nuclear response has been shown to play a vital role in maintaining robust cellular homeostasis, controlling gene expression profiles during developmental phases as well as cell differentiation. Over the last few years, there has been appreciable progress toward identification of the molecular players responsible for force sensing. However, the actual sensing mechanism of cell surface bound force sensors and more importantly cascading of the signals, both physical (via cytosolic force sensing elements such as microtubule and actin framework) and chemical (cascade of biochemical signaling from cell surface to nuclear surface and further to the chromatin), inside the cell is poorly understood. In this chapter, we present a review of the currently known molecular players in cellular as well as nuclear force sensing repertoire and their possible mechanistic aspects. We also introduce various biophysical concepts that are used to describe the force/stress sensing and response of a cell. We hope this will help asking clearer questions and designing pointed experiments for better understanding of the force-dependent design principles of the cell surface, nuclear surface, and gene expression.
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Affiliation(s)
- Bidisha Sinha
- Indian Institute of Science Education and Research Kolkata, Mohanpur, WB, India
| | - Arikta Biswas
- Indian Institute of Science Education and Research Kolkata, Mohanpur, WB, India
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28
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Barrier-to-autointegration factor (BAF) involvement in prelamin A-related chromatin organization changes. Oncotarget 2017; 7:15662-77. [PMID: 26701887 PMCID: PMC4941268 DOI: 10.18632/oncotarget.6697] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2015] [Accepted: 11/21/2015] [Indexed: 11/25/2022] Open
Abstract
Chromatin disorganization is one of the major alterations linked to prelamin A processing impairment. In this study we demonstrate that BAF is necessary to modulate prelamin A effects on chromatin structure. We show that when prelamin A and BAF cannot properly interact no prelamin A-dependent effects on chromatin occur; similar to what is observed in human Nestor Guillermo Progeria Syndrome cells harboring a BAF mutation, in HEK293 cells expressing a BAF mutant unable to bind prelamin A, or in siRNA mediated BAF-depleted HEK293 cells expressing prelamin A. BAF is necessary to induce histone trimethyl-H3K9 as well as HP1-alpha and LAP2-alpha nuclear relocalization in response to prelamin A accumulation. These findings are enforced by electron microscopy evaluations showing how the prelamin A-BAF interaction governs overall chromatin organization. Finally, we demonstrate that the LAP2-alpha nuclear localization defect observed in HGPS cells involves the progerin-BAF interaction, thus establishing a functional link between BAF and prelamin A pathological forms.
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29
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Snyers L, Erhart R, Laffer S, Pusch O, Weipoltshammer K, Schöfer C. LEM4/ANKLE-2 deficiency impairs post-mitotic re-localization of BAF, LAP2α and LaminA to the nucleus, causes nuclear envelope instability in telophase and leads to hyperploidy in HeLa cells. Eur J Cell Biol 2017; 97:63-74. [PMID: 29254732 DOI: 10.1016/j.ejcb.2017.12.001] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2017] [Revised: 12/05/2017] [Accepted: 12/06/2017] [Indexed: 01/01/2023] Open
Abstract
The human LEM-domain protein family is involved in fundamental aspects of nuclear biology. The LEM-domain interacts with the barrier-to-autointegration factor (BAF), which itself binds DNA. LEM-domain proteins LAP2, emerin and MAN1 are proteins of the inner nuclear membrane; they have important functions: maintaining the integrity of the nuclear lamina and regulating gene expression at the nuclear periphery. LEM4/ANKLE-2 has been proposed to participate in nuclear envelope reassembly after mitosis and to mediate dephosphorylation of BAF through binding to phosphatase PP2A. Here, we used CRISPR/Cas9 to create several cell lines deficient in LEM4/ANKLE-2. By using time-lapse video microscopy, we show that absence of this protein severely compromises the post mitotic re-association of the nuclear proteins BAF, LAP2α and LaminA to chromosomes. These defects give rise to a strong mechanical instability of the nuclear envelope in telophase and to a chromosomal instability leading to increased number of hyperploid cells. Reintroducing LEM4/ANKLE-2 in the cells by transfection could efficiently restore the telophase association of BAF and LAP2α to the chromosomes. This rescue phenotype was abolished for N- or C-terminally truncated mutants that had lost the capacity to bind PP2A. We demonstrate also that, in addition to binding to PP2A, LEM4/ANKLE-2 binds BAF through its LEM-domain, providing further evidence for a generic function of this domain as a principal interactor of BAF.
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Affiliation(s)
- Luc Snyers
- Department of Cell and Developmental Biology, Center for Anatomy and Cell Biology, Medical University of Vienna, Schwarzspanierstrasse 17, Vienna, 1090, Austria.
| | - Renate Erhart
- Department of Cell and Developmental Biology, Center for Anatomy and Cell Biology, Medical University of Vienna, Schwarzspanierstrasse 17, Vienna, 1090, Austria
| | - Sylvia Laffer
- Department of Cell and Developmental Biology, Center for Anatomy and Cell Biology, Medical University of Vienna, Schwarzspanierstrasse 17, Vienna, 1090, Austria
| | - Oliver Pusch
- Department of Cell and Developmental Biology, Center for Anatomy and Cell Biology, Medical University of Vienna, Schwarzspanierstrasse 17, Vienna, 1090, Austria
| | - Klara Weipoltshammer
- Department of Cell and Developmental Biology, Center for Anatomy and Cell Biology, Medical University of Vienna, Schwarzspanierstrasse 17, Vienna, 1090, Austria
| | - Christian Schöfer
- Department of Cell and Developmental Biology, Center for Anatomy and Cell Biology, Medical University of Vienna, Schwarzspanierstrasse 17, Vienna, 1090, Austria
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30
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Yu CK, Xu T, Assoian RK, Rader DJ. Mining the Stiffness-Sensitive Transcriptome in Human Vascular Smooth Muscle Cells Identifies Long Noncoding RNA Stiffness Regulators. Arterioscler Thromb Vasc Biol 2017; 38:164-173. [PMID: 29051139 DOI: 10.1161/atvbaha.117.310237] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2017] [Accepted: 09/26/2017] [Indexed: 02/06/2023]
Abstract
OBJECTIVE Vascular extracellular matrix stiffening is a risk factor for aortic and coronary artery disease. How matrix stiffening regulates the transcriptome profile of human aortic and coronary vascular smooth muscle cells (VSMCs) is not well understood. Furthermore, the role of long noncoding RNAs (lncRNAs) in the cellular response to stiffening has never been explored. This study characterizes the stiffness-sensitive (SS) transcriptome of human aortic and coronary VSMCs and identifies potential key lncRNA regulators of stiffness-dependent VSMC functions. APPROACH AND RESULTS Aortic and coronary VSMCs were cultured on hydrogel substrates mimicking physiological and pathological extracellular matrix stiffness. Total RNAseq was performed to compare the SS transcriptome profiles of aortic and coronary VSMCs. We identified 3098 genes (2842 protein coding and 157 lncRNA) that were stiffness sensitive in both aortic and coronary VSMCs (false discovery rate <1%). Hierarchical clustering revealed that aortic and coronary VSMCs grouped by stiffness rather than cell origin. Conservation analyses also revealed that SS genes were more conserved than stiffness-insensitive genes. These VSMC SS genes were less tissue-type specific and expressed in more tissues than stiffness-insensitive genes. Using unbiased systems analyses, we identified MALAT1 as an SS lncRNA that regulates stiffness-dependent VSMC proliferation and migration in vitro and in vivo. CONCLUSIONS This study provides the transcriptomic landscape of human aortic and coronary VSMCs in response to extracellular matrix stiffness and identifies novel SS human lncRNAs. Our data suggest that the SS transcriptome is evolutionarily important to VSMCs function and that SS lncRNAs can act as regulators of stiffness-dependent phenotypes.
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MESH Headings
- Aorta/metabolism
- Aorta/pathology
- Cell Movement
- Cell Proliferation
- Cells, Cultured
- Cluster Analysis
- Computational Biology/methods
- Coronary Vessels/metabolism
- Coronary Vessels/pathology
- Data Mining/methods
- Extracellular Matrix/genetics
- Extracellular Matrix/metabolism
- Extracellular Matrix/pathology
- Gene Expression Profiling/methods
- Gene Expression Regulation
- Humans
- Hydrogels
- Mechanotransduction, Cellular
- Muscle, Smooth, Vascular/metabolism
- Muscle, Smooth, Vascular/pathology
- Myocytes, Smooth Muscle/metabolism
- Myocytes, Smooth Muscle/pathology
- RNA, Long Noncoding/genetics
- RNA, Long Noncoding/metabolism
- Transcriptome
- Vascular Stiffness
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Affiliation(s)
- Christopher K Yu
- From the Perelman School of Medicine (C.K.Y.), Department of Systems Pharmacology and Translational Therapeutics (T.X., R.K.A.), Program in Translational Biomechanics, Institute of Translational Medicine and Therapeutics (T.X., R.K.A.), and Departments of Genetics, Medicine, and Pediatrics, Perelman School of Medicine (D.J.R.), University of Pennsylvania, Philadelphia
- This manuscript was sent to Zahi Fayad, Consulting Editor, for review by expert referees, editorial decision, and final disposition
| | - Tina Xu
- From the Perelman School of Medicine (C.K.Y.), Department of Systems Pharmacology and Translational Therapeutics (T.X., R.K.A.), Program in Translational Biomechanics, Institute of Translational Medicine and Therapeutics (T.X., R.K.A.), and Departments of Genetics, Medicine, and Pediatrics, Perelman School of Medicine (D.J.R.), University of Pennsylvania, Philadelphia
- This manuscript was sent to Zahi Fayad, Consulting Editor, for review by expert referees, editorial decision, and final disposition
| | - Richard K Assoian
- From the Perelman School of Medicine (C.K.Y.), Department of Systems Pharmacology and Translational Therapeutics (T.X., R.K.A.), Program in Translational Biomechanics, Institute of Translational Medicine and Therapeutics (T.X., R.K.A.), and Departments of Genetics, Medicine, and Pediatrics, Perelman School of Medicine (D.J.R.), University of Pennsylvania, Philadelphia
- This manuscript was sent to Zahi Fayad, Consulting Editor, for review by expert referees, editorial decision, and final disposition
| | - Daniel J Rader
- From the Perelman School of Medicine (C.K.Y.), Department of Systems Pharmacology and Translational Therapeutics (T.X., R.K.A.), Program in Translational Biomechanics, Institute of Translational Medicine and Therapeutics (T.X., R.K.A.), and Departments of Genetics, Medicine, and Pediatrics, Perelman School of Medicine (D.J.R.), University of Pennsylvania, Philadelphia.
- This manuscript was sent to Zahi Fayad, Consulting Editor, for review by expert referees, editorial decision, and final disposition.
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31
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Flora P, McCarthy A, Upadhyay M, Rangan P. Role of Chromatin Modifications in Drosophila Germline Stem Cell Differentiation. Results Probl Cell Differ 2017; 59:1-30. [PMID: 28247044 DOI: 10.1007/978-3-319-44820-6_1] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
During Drosophila oogenesis, germline stem cells (GSCs) self-renew and differentiate to give rise to a mature egg. Self-renewal and differentiation of GSCs are regulated by both intrinsic mechanisms such as regulation of gene expression in the germ line and extrinsic signaling pathways from the surrounding somatic niche. Epigenetic mechanisms, including histone-modifying proteins, nucleosome remodeling complexes, and histone variants, play a critical role in regulating intrinsic gene expression and extrinsic signaling cues from the somatic niche. In the GSCs, intrinsic epigenetic modifiers are required to maintain a stem cell fate by promoting expression of self-renewal factors and repressing the differentiation program. Subsequently, in the GSC daughters, epigenetic regulators activate the differentiation program to promote GSC differentiation. During differentiation, the GSC daughter undergoes meiosis to give rise to the developing egg, containing a compacted chromatin architecture called the karyosome. Epigenetic modifiers control the attachment of chromosomes to the nuclear lamina to aid in meiotic recombination and the release from the lamina for karyosome formation. The germ line is in close contact with the soma for the entirety of this developmental process. This proximity facilitates signaling from the somatic niche to the developing germ line. Epigenetic modifiers play a critical role in the somatic niche, modulating signaling pathways in order to coordinate the transition of GSC to an egg. Together, intrinsic and extrinsic epigenetic mechanisms modulate this exquisitely balanced program.
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Affiliation(s)
- Pooja Flora
- Department of Biological Sciences/RNA Institute, University at Albany SUNY, Albany, NY, USA
- University at Albany SUNY, 1400 Washington Avenue, Albany, NY, 12222, USA
| | - Alicia McCarthy
- Department of Biological Sciences/RNA Institute, University at Albany SUNY, Albany, NY, USA
- University at Albany SUNY, 1400 Washington Avenue, Albany, NY, 12222, USA
| | - Maitreyi Upadhyay
- Department of Biological Sciences/RNA Institute, University at Albany SUNY, Albany, NY, USA
- University at Albany SUNY, 1400 Washington Avenue, Albany, NY, 12222, USA
| | - Prashanth Rangan
- Department of Biological Sciences/RNA Institute, University at Albany SUNY, Albany, NY, USA.
- University at Albany SUNY, 1400 Washington Avenue, Albany, NY, 12222, USA.
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32
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Laugks U, Hieke M, Wagner N. MAN1 Restricts BMP Signaling During Synaptic Growth in Drosophila. Cell Mol Neurobiol 2016; 37:1077-1093. [DOI: 10.1007/s10571-016-0442-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2016] [Accepted: 11/05/2016] [Indexed: 01/25/2023]
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33
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Braun S, Barrales RR. Beyond Tethering and the LEM domain: MSCellaneous functions of the inner nuclear membrane Lem2. Nucleus 2016; 7:523-531. [PMID: 27797637 DOI: 10.1080/19491034.2016.1252892] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
The nuclear envelope plays a pivotal role in the functional organization of chromatin. Various inner nuclear membrane (INM) proteins associate with transcriptionally repressed chromatin, which is often found at the nuclear periphery. A prominent example is the conserved family of LEM (LAP2-Emerin-MAN1) domain proteins that interact with DNA-binding proteins and have been proposed to mediate tethering of chromatin to the nuclear membrane. We recently reported that the fission yeast protein Lem2, a homolog of metazoan LEM proteins, contributes to perinuclear localization and silencing of heterochromatin. 1 We demonstrate that binding and tethering of centromeric chromatin depends on the LEM domain of Lem2. Unexpectedly, this domain is dispensable for heterochromatin silencing, which is instead mediated by a different structural domain of Lem2, the MSC (MAN1-Src1 C-terminal) domain. Hence, silencing and tethering by Lem2 can be mechanistically separated. Notably, the MSC domain has multiple functions beyond heterochromatic silencing. Here we discuss the implications of these novel findings for the understanding of this conserved INM protein.
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Affiliation(s)
- Sigurd Braun
- a Department of Physiological Chemistry , Biomedical Center (BMC), Ludwig-Maximilians-University of Munich , Martinsried , Germany
| | - Ramón Ramos Barrales
- a Department of Physiological Chemistry , Biomedical Center (BMC), Ludwig-Maximilians-University of Munich , Martinsried , Germany.,b Present address: Centro Andaluz de Biología del Desarrollo. Universidad Pablo de Olavide, Sevilla-CSIC-Junta de Andalucía , Sevilla , Spain
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34
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Tange Y, Chikashige Y, Takahata S, Kawakami K, Higashi M, Mori C, Kojidani T, Hirano Y, Asakawa H, Murakami Y, Haraguchi T, Hiraoka Y. Inner nuclear membrane protein Lem2 augments heterochromatin formation in response to nutritional conditions. Genes Cells 2016; 21:812-32. [PMID: 27334362 DOI: 10.1111/gtc.12385] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2016] [Accepted: 05/08/2016] [Indexed: 12/29/2022]
Abstract
Inner nuclear membrane proteins interact with chromosomes in the nucleus and are important for chromosome activity. Lem2 and Man1 are conserved members of the LEM-domain nuclear membrane protein family. Mutations of LEM-domain proteins are associated with laminopathy, but their cellular functions remain unclear. Here, we report that Lem2 maintains genome stability in the fission yeast Schizosaccharomyces pombe. S. pombe cells disrupted for the lem2(+) gene (lem2∆) showed slow growth and increased rate of the minichromosome loss. These phenotypes were prominent in the rich culture medium, but not in the minimum medium. Centromeric heterochromatin formation was augmented upon transfer to the rich medium in wild-type cells. This augmentation of heterochromatin formation was impaired in lem2∆ cells. Notably, lem2∆ cells occasionally exhibited spontaneous duplication of genome sequences flanked by the long-terminal repeats of retrotransposons. The resulting duplication of the lnp1(+) gene, which encodes an endoplasmic reticulum membrane protein, suppressed lem2∆ phenotypes, whereas the lem2∆ lnp1∆ double mutant showed a severe growth defect. A combination of mutations in Lem2 and Bqt4, which encodes a nuclear membrane protein that anchors telomeres to the nuclear membrane, caused synthetic lethality. These genetic interactions imply that Lem2 cooperates with the nuclear membrane protein network to regulate genome stability.
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Affiliation(s)
- Yoshie Tange
- Graduate School of Frontier Biosciences, Osaka University, 1-3 Yamadaoka, Suita, 565-0871, Japan.,Advanced ICT Research Institute Kobe, National Institute of Information and Communications Technology, 588-2 Iwaoka, Iwaoka-cho, Nishi-ku, Kobe, 651-2492, Japan
| | - Yuji Chikashige
- Advanced ICT Research Institute Kobe, National Institute of Information and Communications Technology, 588-2 Iwaoka, Iwaoka-cho, Nishi-ku, Kobe, 651-2492, Japan
| | - Shinya Takahata
- Department of Chemistry, Faculty of Science, Hokkaido University, Sapporo, 060-0810, Japan
| | - Kei Kawakami
- Department of Chemistry, Faculty of Science, Hokkaido University, Sapporo, 060-0810, Japan
| | - Masato Higashi
- Graduate school of Chemical Sciences and Engineering, Hokkaido University, Sapporo, 060-0810, Japan
| | - Chie Mori
- Advanced ICT Research Institute Kobe, National Institute of Information and Communications Technology, 588-2 Iwaoka, Iwaoka-cho, Nishi-ku, Kobe, 651-2492, Japan
| | - Tomoko Kojidani
- Advanced ICT Research Institute Kobe, National Institute of Information and Communications Technology, 588-2 Iwaoka, Iwaoka-cho, Nishi-ku, Kobe, 651-2492, Japan.,Laboratory of Electron Microscopy, Faculty of Science, Japan Women's University, 2-8-1 Mejirodai, Bunkyo-ku, Tokyo, 112-8681, Japan
| | - Yasuhiro Hirano
- Graduate School of Frontier Biosciences, Osaka University, 1-3 Yamadaoka, Suita, 565-0871, Japan
| | - Haruhiko Asakawa
- Graduate School of Frontier Biosciences, Osaka University, 1-3 Yamadaoka, Suita, 565-0871, Japan
| | - Yota Murakami
- Department of Chemistry, Faculty of Science, Hokkaido University, Sapporo, 060-0810, Japan
| | - Tokuko Haraguchi
- Graduate School of Frontier Biosciences, Osaka University, 1-3 Yamadaoka, Suita, 565-0871, Japan.,Advanced ICT Research Institute Kobe, National Institute of Information and Communications Technology, 588-2 Iwaoka, Iwaoka-cho, Nishi-ku, Kobe, 651-2492, Japan
| | - Yasushi Hiraoka
- Graduate School of Frontier Biosciences, Osaka University, 1-3 Yamadaoka, Suita, 565-0871, Japan.,Advanced ICT Research Institute Kobe, National Institute of Information and Communications Technology, 588-2 Iwaoka, Iwaoka-cho, Nishi-ku, Kobe, 651-2492, Japan
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Zlopasa L, Brachner A, Foisner R. Nucleo-cytoplasmic shuttling of the endonuclease ankyrin repeats and LEM domain-containing protein 1 (Ankle1) is mediated by canonical nuclear export- and nuclear import signals. BMC Cell Biol 2016; 17:23. [PMID: 27245214 PMCID: PMC4888674 DOI: 10.1186/s12860-016-0102-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2016] [Accepted: 05/19/2016] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Ankyrin repeats and LEM domain containing protein 1 (Ankle1) belongs to the LEM protein family, whose members share a chromatin-interacting LEM motif. Unlike most other LEM proteins, Ankle1 is not an integral protein of the inner nuclear membrane but shuttles between the nucleus and the cytoplasm. It contains a GIY-YIG-type nuclease domain, but its function is unknown. The mammalian genome encodes only one other GIY-YIG domain protein, termed Slx1. Slx1 has been described as a resolvase that processes Holliday junctions during homologous recombination-mediated DNA double strand break repair. Resolvase activity is regulated in a spatial and temporal manner during the cell cycle. We hypothesized that Ankle1 may have a similar function and its nucleo-cytoplasmic shuttling may contribute to the regulation of Ankle1 activity. Hence, we aimed at identifying the domains mediating Ankle1 shuttling and investigating whether cellular localization is affected during DNA damage response. RESULTS Sequence analysis predicts the presence of two canonical nuclear import and export signals in Ankle1. Immunofluorescence microscopy of cells expressing wild-type and various mutated Ankle1-fusion proteins revealed a C-terminally located classical monopartite nuclear localization signal and a centrally located CRM1-dependent nuclear export signal that mediate nucleo-cytoplasmic shuttling of Ankle1. These sequences are also functional in heterologous proteins. The predominant localization of Ankle1 in the cytoplasm, however, does not change upon induction of several DNA damage response pathways throughout the cell cycle. CONCLUSIONS We identified the domains mediating nuclear import and export of Ankle1. Ankle1's cellular localization was not affected following DNA damage.
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Affiliation(s)
- Livija Zlopasa
- Max F. Perutz Laboratories (MFPL), Department of Medical Biochemistry, Medical University of Vienna, Vienna Biocenter (VBC), Vienna, Austria
| | - Andreas Brachner
- Max F. Perutz Laboratories (MFPL), Department of Medical Biochemistry, Medical University of Vienna, Vienna Biocenter (VBC), Vienna, Austria.
| | - Roland Foisner
- Max F. Perutz Laboratories (MFPL), Department of Medical Biochemistry, Medical University of Vienna, Vienna Biocenter (VBC), Vienna, Austria.
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Barton LJ, Lovander KE, Pinto BS, Geyer PK. Drosophila male and female germline stem cell niches require the nuclear lamina protein Otefin. Dev Biol 2016; 415:75-86. [PMID: 27174470 DOI: 10.1016/j.ydbio.2016.05.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2015] [Revised: 04/28/2016] [Accepted: 05/02/2016] [Indexed: 12/11/2022]
Abstract
The nuclear lamina is an extensive protein network that underlies the inner nuclear envelope. This network includes the LAP2-emerin-MAN1-domain (LEM-D) protein family, proteins that share an association with the chromatin binding protein Barrier-to-autointegration factor (BAF). Loss of individual LEM-D proteins causes progressive, tissue-restricted diseases, known as laminopathies. Mechanisms associated with laminopathies are not yet understood. Here we present our studies of one of the Drosophila nuclear lamina LEM-D proteins, Otefin (Ote), a homologue of emerin. Previous studies have shown that Ote is autonomously required for the survival of female germline stem cells (GSCs). We demonstrate that Ote is also required for survival of somatic cells in the ovarian niche, with loss of Ote causing a decrease in cap cell number and altered signal transduction. We show germ cell-restricted expression of Ote rescues these defects, revealing a non-autonomous function for Ote in niche maintenance and emphasizing that GSCs contribute to the maintenance of their own niches. Further, we investigate the requirement of Ote in the male fertility. We show that ote mutant males become prematurely sterile as they age. Parallel to observations in females, this sterility is associated with GSC loss and changes in somatic cells of the niche, phenotypes that are largely rescued by germ cell-restricted Ote expression. Taken together, our studies demonstrate that Ote is required autonomously for survival of two stem cell populations, as well as non-autonomously for maintenance of two somatic niches. Finally, our data add to growing evidence that LEM-D proteins have critical roles in stem cell survival and tissue homeostasis.
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Affiliation(s)
- Lacy J Barton
- Department of Biochemistry, University of Iowa, Iowa City, IA 52242, USA
| | - Kaylee E Lovander
- Department of Biochemistry, University of Iowa, Iowa City, IA 52242, USA
| | - Belinda S Pinto
- Department of Biochemistry, University of Iowa, Iowa City, IA 52242, USA
| | - Pamela K Geyer
- Department of Biochemistry, University of Iowa, Iowa City, IA 52242, USA.
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37
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Voelzmann A, Wulf AL, Eckardt F, Thielisch M, Brondolin M, Pesch YY, Sociale M, Bauer R, Hoch M. NuclearDrosophilaCerS Schlank regulates lipid homeostasis via the homeodomain, independent of the lag1p motif. FEBS Lett 2016; 590:971-81. [DOI: 10.1002/1873-3468.12125] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2015] [Revised: 02/17/2016] [Accepted: 03/03/2016] [Indexed: 11/08/2022]
Affiliation(s)
- André Voelzmann
- Program Unit Development, Genetics & Molecular Physiology; Laboratory for Molecular Developmental Biology; LIMES-Institute; University of Bonn; Germany
| | - Anna-Lena Wulf
- Program Unit Development, Genetics & Molecular Physiology; Laboratory for Molecular Developmental Biology; LIMES-Institute; University of Bonn; Germany
| | - Franka Eckardt
- Program Unit Development, Genetics & Molecular Physiology; Laboratory for Molecular Developmental Biology; LIMES-Institute; University of Bonn; Germany
| | - Melanie Thielisch
- Program Unit Development, Genetics & Molecular Physiology; Laboratory for Molecular Developmental Biology; LIMES-Institute; University of Bonn; Germany
| | - Mirco Brondolin
- Program Unit Development, Genetics & Molecular Physiology; Laboratory for Molecular Developmental Biology; LIMES-Institute; University of Bonn; Germany
| | - Yanina-Yasmin Pesch
- Program Unit Development, Genetics & Molecular Physiology; Laboratory for Molecular Developmental Biology; LIMES-Institute; University of Bonn; Germany
| | - Mariangela Sociale
- Program Unit Development, Genetics & Molecular Physiology; Laboratory for Molecular Developmental Biology; LIMES-Institute; University of Bonn; Germany
| | - Reinhard Bauer
- Program Unit Development, Genetics & Molecular Physiology; Laboratory for Molecular Developmental Biology; LIMES-Institute; University of Bonn; Germany
| | - Michael Hoch
- Program Unit Development, Genetics & Molecular Physiology; Laboratory for Molecular Developmental Biology; LIMES-Institute; University of Bonn; Germany
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38
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Braun J, Meixner A, Brachner A, Foisner R. The GIY-YIG Type Endonuclease Ankyrin Repeat and LEM Domain-Containing Protein 1 (ANKLE1) Is Dispensable for Mouse Hematopoiesis. PLoS One 2016; 11:e0152278. [PMID: 27010503 PMCID: PMC4807109 DOI: 10.1371/journal.pone.0152278] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2015] [Accepted: 03/12/2016] [Indexed: 01/01/2023] Open
Abstract
Ankyrin repeat and LEM-domain containing protein 1 (ANKLE1) is a GIY-YIG endonuclease with unknown functions, mainly expressed in mouse hematopoietic tissues. To test its potential role in hematopoiesis we generated Ankle1-deficient mice. Ankle1Δ/Δ mice are viable without any detectable phenotype in hematopoiesis. Neither hematopoietic progenitor cells, myeloid and lymphoid progenitors, nor B and T cell development in bone marrow, spleen and thymus, are affected in Ankle1Δ/Δ-mice. Similarly embryonic stress erythropoiesis in liver and adult erythropoiesis in bone marrow and spleen appear normal. To test whether ANKLE1, like the only other known GIY-YIG endonuclease in mammals, SLX1, may contribute to Holliday junction resolution during DNA repair, Ankle1-deficient cells were exposed to various DNA-damage inducing agents. However, lack of Ankle1 did not affect cell viability and, unlike depletion of Slx1, Ankle1-deficiency did not increase sister chromatid exchange in Bloom helicase-depleted cells. Altogether, we show that lack of Ankle1 does neither affect mouse hematopoiesis nor DNA damage repair in mouse embryonic fibroblasts, indicating a redundant or non-essential function of ANKLE1 in mouse.
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Affiliation(s)
- Juliane Braun
- Max F. Perutz Laboratories (MFPL), Department of Medical Biochemistry, Medical University of Vienna, Vienna Biocenter (VBC), Vienna, Austria
| | - Arabella Meixner
- IMBA-Institute of Molecular Biotechnology of the Austrian Academy of Sciences, Vienna, Austria
| | - Andreas Brachner
- Max F. Perutz Laboratories (MFPL), Department of Medical Biochemistry, Medical University of Vienna, Vienna Biocenter (VBC), Vienna, Austria
| | - Roland Foisner
- Max F. Perutz Laboratories (MFPL), Department of Medical Biochemistry, Medical University of Vienna, Vienna Biocenter (VBC), Vienna, Austria
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39
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Jamin A, Wiebe MS. Barrier to Autointegration Factor (BANF1): interwoven roles in nuclear structure, genome integrity, innate immunity, stress responses and progeria. Curr Opin Cell Biol 2015; 34:61-8. [PMID: 26072104 DOI: 10.1016/j.ceb.2015.05.006] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2014] [Revised: 05/20/2015] [Accepted: 05/27/2015] [Indexed: 11/24/2022]
Abstract
The Barrier to Autointegration Factor (BAF or BANF1) is an abundant, highly conserved DNA binding protein. BAF is involved in multiple pathways including mitosis, nuclear assembly, viral infection, chromatin and gene regulation and the DNA damage response. BAF is also essential for early development in metazoans and relevant to human physiology; BANF1 mutations cause a progeroid syndrome, placing BAF within the laminopathy disease spectrum. This review summarizes previous knowledge about BAF in the context of recent discoveries about its protein partners, posttranslational regulation, dynamic subcellular localizations and roles in disease, innate immunity, transposable elements and genome integrity.
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Affiliation(s)
- Augusta Jamin
- School of Veterinary Medicine and Biomedical Sciences, University of Nebraska, Lincoln, NE 68583-0900, USA; Nebraska Center for Virology, University of Nebraska, Lincoln, NE 68583-0900, USA
| | - Matthew S Wiebe
- School of Veterinary Medicine and Biomedical Sciences, University of Nebraska, Lincoln, NE 68583-0900, USA; Nebraska Center for Virology, University of Nebraska, Lincoln, NE 68583-0900, USA.
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40
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Barton LJ, Soshnev AA, Geyer PK. Networking in the nucleus: a spotlight on LEM-domain proteins. Curr Opin Cell Biol 2015; 34:1-8. [PMID: 25863918 DOI: 10.1016/j.ceb.2015.03.005] [Citation(s) in RCA: 137] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2014] [Revised: 03/23/2015] [Accepted: 03/25/2015] [Indexed: 11/29/2022]
Abstract
Proteins resident in the inner nuclear membrane and underlying nuclear lamina form a network that regulates nuclear functions. This review highlights a prominent family of nuclear lamina proteins that carries the LAP2-emerin-MAN1-domain (LEM-D). LEM-D proteins share an ability to bind lamins and tether repressive chromatin at the nuclear periphery. The importance of this family is underscored by findings that loss of individual LEM-D proteins causes progressive, tissue-restricted diseases, known as laminopathies. Diverse functions of LEM-D proteins are linked to interactions with unique and overlapping partners including signal transduction effectors, transcription factors and architectural proteins. Recent investigations suggest that LEM-D proteins form hubs within the nuclear lamina that integrate external signals important for tissue homeostasis and maintenance of progenitor cell populations.
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Affiliation(s)
- Lacy J Barton
- Department of Biochemistry, University of Iowa, College of Medicine, Iowa City, IA 52242, USA; Skirball Institute, Department of Cell Biology, NYU School of Medicine, NYU Langone Medical Center, New York, NY 10016, USA
| | - Alexey A Soshnev
- Laboratory of Chromatin Biology and Epigenetics, The Rockefeller University, New York, NY, 10065, USA
| | - Pamela K Geyer
- Department of Biochemistry, University of Iowa, College of Medicine, Iowa City, IA 52242, USA.
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41
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Zhou X, Graumann K, Meier I. The plant nuclear envelope as a multifunctional platform LINCed by SUN and KASH. JOURNAL OF EXPERIMENTAL BOTANY 2015; 66:1649-59. [PMID: 25740919 DOI: 10.1093/jxb/erv082] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
The nuclear envelope (NE) is a double membrane system enclosing the genome of eukaryotes. Besides nuclear pore proteins, which form channels at the NE, nuclear membranes are populated by a collection of NE proteins that perform various cellular functions. However, in contrast to well-conserved nuclear pore proteins, known NE proteins share little homology between opisthokonts and plants. Recent studies on NE protein complexes formed by Sad1/UNC-84 (SUN) and Klarsicht/ANC-1/Syne-1 Homology (KASH) proteins have advanced our understanding of plant NE proteins and revealed their function in anchoring other proteins at the NE, nuclear shape determination, nuclear positioning, anti-pathogen defence, root development, and meiotic chromosome organization. In this review, we discuss the current understanding of plant SUN, KASH, and other related NE proteins, and compare their function with the opisthokont counterparts.
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Affiliation(s)
- Xiao Zhou
- Department of Molecular Genetics, The Ohio State University, Columbus, OH 43210, USA
| | - Katja Graumann
- Department of Biological and Medical Sciences, Faculty of Health and Life Sciences, Oxford Brookes University, Headington Campus, Oxford OX3 OBP, UK
| | - Iris Meier
- Department of Molecular Genetics, The Ohio State University, Columbus, OH 43210, USA
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42
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Poleshko A, Mansfield KM, Burlingame CC, Andrake MD, Shah NR, Katz RA. The human protein PRR14 tethers heterochromatin to the nuclear lamina during interphase and mitotic exit. Cell Rep 2015; 5:292-301. [PMID: 24209742 DOI: 10.1016/j.celrep.2013.09.024] [Citation(s) in RCA: 79] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2013] [Revised: 05/21/2013] [Accepted: 09/16/2013] [Indexed: 11/25/2022] Open
Abstract
The nuclear lamina is a protein meshwork that lies under the inner nuclear membrane of metazoan cells. One function of the nuclear lamina is to organize heterochromatin at the inner nuclear periphery. However, very little is known about how heterochromatin attaches to the nuclear lamina and how such attachments are restored at mitotic exit. Here, we show that a previously unstudied human protein, PRR14, functions to tether heterochromatin to the nuclear periphery during interphase, through associations with heterochromatin protein 1 (HP1) and the nuclear lamina. During early mitosis, PRR14 is released from the nuclear lamina and chromatin and remains soluble. Strikingly, at the onset of anaphase, PRR14 is incorporated rapidly into chromatin through HP1 binding. Finally, in telophase, PRR14 relocalizes to the reforming nuclear lamina. This stepwise reassembly of PRR14 suggests a function in the selection of HP1-bound heterochromatin for reattachment to the nuclear lamina as cells exit mitosis.
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43
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Carmosino M, Torretta S, Procino G, Gerbino A, Forleo C, Favale S, Svelto M. Role of nuclear Lamin A/C in cardiomyocyte functions. Biol Cell 2014; 106:346-58. [PMID: 25055884 DOI: 10.1111/boc.201400033] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2014] [Accepted: 07/16/2014] [Indexed: 12/21/2022]
Abstract
Lamin A/C is a structural protein of the nuclear envelope (NE) and cardiac involvement in Lamin A/C mutations was one of the first phenotypes to be reported in humans, suggesting a crucial role of this protein in the cardiomyocytes function. Mutations in LMNA gene cause a class of pathologies generically named 'Lamanopathies' mainly involving heart and skeletal muscles. Moreover, the well-known disease called Hutchinson-Gilford Progeria Syndrome due to extensive mutations in LMNA gene, in addition to the systemic phenotype of premature aging, is characterised by the death of patients at around 13 typically for a heart attack or stroke, suggesting again the heart as the main site sensitive to Lamin A/C disfunction. Indeed, the identification of the roles of the Lamin A/C in cardiomyocytes function is a key area of exploration. One of the primary biological roles recently conferred to Lamin A/C is to affect contractile cells lineage determination and senescence. Then, in differentiated adult cardiomyocytes both the 'structural' and 'gene expression hypothesis' could explain the role of Lamin A in the function of cardiomyocytes. In fact, recent advances in the field propose that the structural weakness/stiffness of the NE, regulated by Lamin A/C amount in NE, can 'consequently' alter gene expression.
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Affiliation(s)
- Monica Carmosino
- Department of Sciences, University of Basilicata, Potenza, Italy; Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari, Bari, Italy
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44
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Berk JM, Simon DN, Jenkins-Houk CR, Westerbeck JW, Grønning-Wang LM, Carlson CR, Wilson KL. The molecular basis of emerin-emerin and emerin-BAF interactions. J Cell Sci 2014; 127:3956-69. [PMID: 25052089 DOI: 10.1242/jcs.148247] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
Emerin is a conserved membrane component of nuclear lamina structure. Here, we report an advance in understanding the molecular basis of emerin function: intermolecular emerin-emerin association. There were two modes: one mediated by association of residues 170-220 in one emerin molecule to residues 170-220 in another, and the second involving residues 170-220 and 1-132. Deletion analysis showed residues 187-220 contain a positive element essential for intermolecular association in cells. By contrast, deletion of residues 168-186 inactivated a proposed negative element, required to limit or control association. Association of GFP-emerin with nuclear BAF in cells required the LEM domain (residues 1-47) and the positive element. Emerin peptide arrays revealed direct binding of residues 170-220 to residues 206-225 (the proposed positive element), residues 147-174 (particularly P(153)MYGRDSAYQSITHYRP(169)) and the LEM domain. Emerin residues 1-132 and 159-220 were each sufficient to bind lamin A or B1 tails in vitro, identifying two independent regions of molecular contact with lamins. These results, and predicted emerin intrinsic disorder, support the hypothesis that there are multiple 'backbone' and LEM-domain configurations in a proposed intermolecular emerin network at the nuclear envelope.
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Affiliation(s)
- Jason M Berk
- Department of Cell Biology, Johns Hopkins University School of Medicine, 725 N. Wolfe Street, Baltimore, MD 21205 USA
| | - Dan N Simon
- Department of Cell Biology, Johns Hopkins University School of Medicine, 725 N. Wolfe Street, Baltimore, MD 21205 USA
| | - Clifton R Jenkins-Houk
- Department of Cell Biology, Johns Hopkins University School of Medicine, 725 N. Wolfe Street, Baltimore, MD 21205 USA
| | - Jason W Westerbeck
- Department of Cell Biology, Johns Hopkins University School of Medicine, 725 N. Wolfe Street, Baltimore, MD 21205 USA
| | - Line M Grønning-Wang
- Department of Nutrition, Institute of Basic Medical Sciences, University of Oslo, 0317 Oslo, Norway
| | - Cathrine R Carlson
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, 0424 Oslo, Norway KG Jebsen Cardiac Research Center and Center for Heart Failure Research, University of Oslo, 0450 Oslo, Norway
| | - Katherine L Wilson
- Department of Cell Biology, Johns Hopkins University School of Medicine, 725 N. Wolfe Street, Baltimore, MD 21205 USA
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45
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Zhang M, Chen J, Si D, Zheng Y, Jiao H, Feng Z, Hu Z, Duan R. Whole exome sequencing identifies a novel EMD mutation in a Chinese family with dilated cardiomyopathy. BMC MEDICAL GENETICS 2014; 15:77. [PMID: 24997722 PMCID: PMC4105140 DOI: 10.1186/1471-2350-15-77] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/21/2014] [Accepted: 06/27/2014] [Indexed: 01/21/2023]
Abstract
BACKGROUND Variants in the emerin gene (EMD) were implicated in X-linked recessive Emery-Dreifuss muscular dystrophy (EDMD), characterized by early-onset contractures of tendons, progressive muscular weakness and cardiomyopathy. To date, 223 mutations have been reported in EMD gene and the majority of them caused a predominant skeletal muscular phenotype. In this study, we identified a novel deletion mutation in EMD exon 1, which results in almost a complete loss of emerin protein in a large Chinese family. However, the patients suffered severe dilated cardiomyopathy (DCM) but very mild skeletal muscle disorder. CASE PRESENTATION Whole exome sequencing (WES) and linkage analysis were performed to identify the underlying mutation in a Chinese DCM family spanning five generations. A missense variation in the GPR50 gene was found co-segregated with the disease phenotype, whereas no functional alteration was detected in the variant GPR50 protein. When analyzing the failure sequences in the exome sequencing data, a novel deletion mutation (c.26_39delATACCGAGCTGACC) in EMD exon 1, was identified in this family. Different from the typical clinical features caused by most reported EMD mutations, patients in our study presented very mild skeletal muscle degeneration that had not been diagnosed until the mutation was found. CONCLUSION We described a family with rare clinical presentations caused by a novel EMD deletion mutation. Our findings broaden the heterogeneous spectrum of phenotypes attributed to EMD mutations and provide new insight to explain the genotype-phenotype correlations between EMD mutations and EDMD symptoms.
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Affiliation(s)
- Mingqiu Zhang
- China Japan Union Hospital, Jilin University, 130031 Changchun, Jilin province, China
| | - Jia Chen
- State Key Lab of Medical Genetics, Central South University, 410008 Changsha, Hunan province, China
| | - Dayong Si
- School of Life Science, Jilin University, 130031 Changchun, Jilin province, China
| | - Yu Zheng
- State Key Lab of Medical Genetics, Central South University, 410008 Changsha, Hunan province, China
| | - Haixu Jiao
- China Japan Union Hospital, Jilin University, 130031 Changchun, Jilin province, China
| | - Zhaohui Feng
- China Japan Union Hospital, Jilin University, 130031 Changchun, Jilin province, China
| | - Zhengmao Hu
- State Key Lab of Medical Genetics, Central South University, 410008 Changsha, Hunan province, China
| | - Ranhui Duan
- State Key Lab of Medical Genetics, Central South University, 410008 Changsha, Hunan province, China
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46
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Swift J, Discher DE. The nuclear lamina is mechano-responsive to ECM elasticity in mature tissue. J Cell Sci 2014; 127:3005-15. [PMID: 24963133 DOI: 10.1242/jcs.149203] [Citation(s) in RCA: 144] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
How cells respond to physical cues in order to meet and withstand the physical demands of their immediate surroundings has been of great interest for many years, with current research efforts focused on mechanisms that transduce signals into gene expression. Pathways that mechano-regulate the entry of transcription factors into the cell nucleus are emerging, and our most recent studies show that the mechanical properties of the nucleus itself are actively controlled in response to the elasticity of the extracellular matrix (ECM) in both mature and developing tissue. In this Commentary, we review the mechano-responsive properties of nuclei as determined by the intermediate filament lamin proteins that line the inside of the nuclear envelope and that also impact upon transcription factor entry and broader epigenetic mechanisms. We summarize the signaling pathways that regulate lamin levels and cell-fate decisions in response to a combination of ECM mechanics and molecular cues. We will also discuss recent work that highlights the importance of nuclear mechanics in niche anchorage and cell motility during development, hematopoietic differentiation and cancer metastasis, as well as emphasizing a role for nuclear mechanics in protecting chromatin from stress-induced damage.
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Affiliation(s)
- Joe Swift
- Molecular and Cell Biophysics Lab, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Dennis E Discher
- Molecular and Cell Biophysics Lab, University of Pennsylvania, Philadelphia, PA 19104, USA
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47
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Amendola M, van Steensel B. Mechanisms and dynamics of nuclear lamina–genome interactions. Curr Opin Cell Biol 2014; 28:61-8. [DOI: 10.1016/j.ceb.2014.03.003] [Citation(s) in RCA: 98] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2013] [Revised: 03/06/2014] [Accepted: 03/08/2014] [Indexed: 12/21/2022]
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48
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Shang YD, Zhang JL, Zhang HX, Zheng QC. Molecular simulation investigation on the interaction between barrier-to-autointegration factor or its Gly25Glu mutant and DNA. J Mol Model 2014; 20:2246. [PMID: 24797088 DOI: 10.1007/s00894-014-2246-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2013] [Accepted: 04/09/2014] [Indexed: 11/25/2022]
Abstract
In order to understand the binding mechanism between Barrier-to-autointegration factor (BAF) and DNA, two DNA:BAF complexes with wild type (WT) BAF and its Gly25Glu point mutate type (MT) were generated by molecular docking on the basis of the crystal structures of BAF (PDB code: 2ODG, chain A) and DNA (PDB code: 2BZF, chain B and C). Then, molecular dynamics (MD) simulations were performed on the two docked structures, as well as BAF (WT) and BAF (MT). The results show that monomer BAF is more flexible than BAF in DNA:BAF complex, suggesting that DNA is effective to stabilize conformation of BAF, which is in good agreement with the experimental results. Besides, the mutated Glu25 in DNA:BAF (MT) can change the BAF conformation to some extent. With deeper investigation on the DNA:BAF structures, the hydrogen bonds are found to make great contribution to the interaction between DNA and BAF. The hydrogen bonds in DNA:BAF (MT) are fewer than those in DNA:BAF (WT), indicating that the Gly25Glu mutation in BAF has an important effect on the hydrogen bonds in the DNA:BAF complex. Besides, the binding free energy in DNA:BAF (MT) is also higher than that in DNA:BAF (WT). It results from the influence of Glu25 side chain on the orientation of Lys6 and Lys33 in the interface between DNA and BAF. The binding free energy of Lys72, another key residue, decreases a lot in DNA:BAF (MT) anomalously. The decreasing energy causes the destruction of hydrophobic pocket in the binding site between DNA and BAF (MT). Our results are helpful for further experimental investigations.
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Affiliation(s)
- Yu-Dong Shang
- State Key Laboratory of Theoretical and Computational Chemistry, Institute of Theoretical Chemistry, Jilin University, Changchun, 130023, Jilin, People's Republic of China
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Abstract
The nuclear lamina is an extensive protein network that contributes to nuclear structure and function. LEM domain (LAP2, emerin, MAN1 domain, LEM-D) proteins are components of the nuclear lamina, identified by a shared ∼45-amino-acid motif that binds Barrier-to-autointegration factor (BAF), a chromatin-interacting protein. Drosophila melanogaster has three nuclear lamina LEM-D proteins, named Otefin (Ote), Bocksbeutel (Bocks), and dMAN1. Although these LEM-D proteins are globally expressed, loss of either Ote or dMAN1 causes tissue-specific defects in adult flies that differ from each other. The reason for such distinct tissue-restricted defects is unknown. Here, we generated null alleles of bocks, finding that loss of Bocks causes no overt adult phenotypes. Next, we defined phenotypes associated with lem-d double mutants. Although the absence of individual LEM-D proteins does not affect viability, loss of any two proteins causes lethality. Mutant phenotypes displayed by lem-d double mutants differ from baf mutants, suggesting that BAF function is retained in animals with a single nuclear lamina LEM-D protein. Interestingly, lem-d double mutants displayed distinct developmental and cellular mutant phenotypes, suggesting that Drosophila LEM-D proteins have developmental functions that are differentially shared with other LEM-D family members. This conclusion is supported by studies showing that ectopically produced LEM-D proteins have distinct capacities to rescue the tissue-specific phenotypes found in single lem-d mutants. Our findings predict that cell-specific mutant phenotypes caused by loss of LEM-D proteins reflect both the constellation of LEM-D proteins within the nuclear lamina and the capacity of functional compensation of the remaining LEM-D proteins.
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Stroud MJ, Banerjee I, Veevers J, Chen J. Linker of nucleoskeleton and cytoskeleton complex proteins in cardiac structure, function, and disease. Circ Res 2014; 114:538-48. [PMID: 24481844 DOI: 10.1161/circresaha.114.301236] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
The linker of nucleoskeleton and cytoskeleton (LINC) complex, composed of proteins within the inner and the outer nuclear membranes, connects the nuclear lamina to the cytoskeleton. The importance of this complex has been highlighted by the discovery of mutations in genes encoding LINC complex proteins, which cause skeletal or cardiac myopathies. Herein, this review summarizes structure, function, and interactions of major components of the LINC complex, highlights how mutations in these proteins may lead to cardiac disease, and outlines future challenges in the field.
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Affiliation(s)
- Matthew J Stroud
- From the Department of Cardiology, University of California San Diego School of Medicine, La Jolla, CA
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