1
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Lu X, Shi Y, Lu Q, Ma Y, Luo J, Wang Q, Ji J, Jiang Q, Zhang C. Requirement for lamin B receptor and its regulation by importin {beta} and phosphorylation in nuclear envelope assembly during mitotic exit. J Biol Chem 2010; 285:33281-33293. [PMID: 20576617 PMCID: PMC2963407 DOI: 10.1074/jbc.m110.102368] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2010] [Revised: 06/24/2010] [Indexed: 11/06/2022] Open
Abstract
Lamin B receptor (LBR), a chromatin and lamin B-binding protein in the inner nuclear membrane, has been proposed to target the membrane precursor vesicles to chromatin mediated by importin β during the nuclear envelope (NE) assembly. However, the mechanisms for the binding of LBR with importin β and the membrane targeting by LBR in NE assembly remain largely unknown. In this report, we show that the amino acids (aa) 69-90 of LBR sequences are required to bind with importin β at aa 45-462, and the binding is essential for the NE membrane precursor vesicle targeting to the chromatin during the NE assembly at the end of mitosis. We also show that this binding is cell cycle-regulated and dependent on the phosphorylation of LBR Ser-71 by p34(cdc2) kinase. RNAi knockdown of LBR causes the NE assembly failure and abnormal chromatin decondensation of the daughter cell nuclei, leading to the daughter cell death at early G(1) phase by apoptosis. Perturbation of the interaction of LBR with importin β by deleting the LBR N-terminal spanning region or aa 69-73 also induces the NE assembly failure, the abnormal chromatin decondensation, and the daughter cell death. The first transmembrane domain of LBR promotes the NE production and expansion, because overexpressing this domain is sufficient to induce membrane overproduction of the NE. Thus, these results demonstrate that LBR targets the membrane precursor vesicles to chromatin by interacting with importin β in a LBR phosphorylation-dependent manner during the NE assembly at the end of mitosis and that the first transmembrane domain of LBR promotes the LBR-bearing membrane production and the NE expansion in interphase.
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Affiliation(s)
- Xuelong Lu
- From the The Key Laboratory of Cell Proliferation and Differentiation of the Ministry of Education and the State Key Laboratory of Bio-membrane and Membrane Bio-engineering, Beijing 100871, China
| | - Yang Shi
- From the The Key Laboratory of Cell Proliferation and Differentiation of the Ministry of Education and the State Key Laboratory of Bio-membrane and Membrane Bio-engineering, Beijing 100871, China
| | - Quanlong Lu
- From the The Key Laboratory of Cell Proliferation and Differentiation of the Ministry of Education and the State Key Laboratory of Bio-membrane and Membrane Bio-engineering, Beijing 100871, China
| | - Yan Ma
- From the The Key Laboratory of Cell Proliferation and Differentiation of the Ministry of Education and the State Key Laboratory of Bio-membrane and Membrane Bio-engineering, Beijing 100871, China
| | - Jia Luo
- From the The Key Laboratory of Cell Proliferation and Differentiation of the Ministry of Education and the State Key Laboratory of Bio-membrane and Membrane Bio-engineering, Beijing 100871, China
| | - Qingsong Wang
- State Laboratory of Protein Engineering and Plant Genetic Engineering, College of Life Sciences, Peking University, Beijing 100871, China
| | - Jianguo Ji
- State Laboratory of Protein Engineering and Plant Genetic Engineering, College of Life Sciences, Peking University, Beijing 100871, China
| | - Qing Jiang
- From the The Key Laboratory of Cell Proliferation and Differentiation of the Ministry of Education and the State Key Laboratory of Bio-membrane and Membrane Bio-engineering, Beijing 100871, China
| | - Chuanmao Zhang
- From the The Key Laboratory of Cell Proliferation and Differentiation of the Ministry of Education and the State Key Laboratory of Bio-membrane and Membrane Bio-engineering, Beijing 100871, China.
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2
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Olins AL, Rhodes G, Welch DBM, Zwerger M, Olins DE. Lamin B receptor: multi-tasking at the nuclear envelope. Nucleus 2010; 1:53-70. [PMID: 21327105 PMCID: PMC3035127 DOI: 10.4161/nucl.1.1.10515] [Citation(s) in RCA: 101] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2009] [Revised: 11/01/2009] [Accepted: 11/04/2009] [Indexed: 12/11/2022] Open
Abstract
Lamin B receptor (LBR) is an integral membrane protein of the interphase nuclear envelope (NE). The N-terminal end resides in the nucleoplasm, binding to lamin B and heterochromatin, with the interactions disrupted during mitosis. The C-terminal end resides within the inner nuclear membrane, retreating with the ER away from condensing chromosomes during mitotic NE breakdown. Some of these properties are interpretable in terms of our current structural knowledge of LBR, but many of the structural features remain unknown. LBR apparently has an evolutionary history which brought together at least two ancient conserved structural domains (i.e., Tudor and sterol reductase). This convergence may have occurred with the emergence of the chordates and echinoderms. It is not clear what survival values have maintained LBR structure during evolution. But it seems likely that roles in post-mitotic nuclear reformation, interphase NE growth and compartmentalization of nuclear architecture might have provided some evolutionary advantage to preservation of the LBR gene.
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Affiliation(s)
- Ada L Olins
- Department of Biology, Bowdoin College, Brunswick, ME, USA
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3
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Schild-Prüfert K, Giegerich M, Schäfer M, Winkler C, Krohne G. Structural and functional characterization of the zebrafish lamin B receptor. Eur J Cell Biol 2006; 85:813-24. [PMID: 16759737 DOI: 10.1016/j.ejcb.2006.04.009] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2006] [Revised: 04/21/2006] [Accepted: 04/21/2006] [Indexed: 11/28/2022] Open
Abstract
The lamin B receptor (LBR) is an integral membrane protein of the inner nuclear membrane that is interacting with B-type lamins, chromatin and DNA. The complete loss of the protein in mouse mutants causes a reduced viability of embryos, and viable animals develop abnormalities of the skeleton. Here, we present the molecular characterization of the zebrafish LBR (zLBR) gene and the functional analysis of LBR during zebrafish embryogenesis. We found that the coding region of the LBR mRNA of zebrafish as well as of mammals is contained in 13 exons. At the protein level, human and zebrafish LBR exhibit a high sequence identity (57% and higher) in 8 of the 13 exons. Knockdown of zLBR by microinjection of 0.5-1.0 mM morpholino antisense oligonucleotides (MO) into 1- to 2-cell stage embryos reduced the amount of endogenous zLBR protein to approximately 10-20%. The viability of MO-injected embryos within 24 h was reduced to 70-77%. Surviving 1-day-old embryos exhibited morphological alterations including reduced growth of head structures, retardation of tail growth and a bent backbone and tail. Expression analysis of the transcription factors no tail (ntl) and goosecoid (gsc) by in situ hybridization suggests that these malformations are caused by altered cell migration during gastrulation. Our data indicate that the LBR of zebrafish and mammals are both required for correct development.
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MESH Headings
- Amino Acid Sequence
- Animals
- Base Sequence
- DNA, Complementary/chemistry
- DNA, Complementary/genetics
- Electrophoresis, Polyacrylamide Gel
- Embryo, Nonmammalian/cytology
- Embryo, Nonmammalian/embryology
- Embryo, Nonmammalian/metabolism
- Exons/genetics
- Fetal Proteins
- Gene Expression Regulation, Developmental
- Gene Silencing
- Goosecoid Protein/genetics
- Goosecoid Protein/metabolism
- Humans
- Immunoblotting
- Introns/genetics
- Molecular Sequence Data
- Mutation
- Receptors, Cytoplasmic and Nuclear/genetics
- Receptors, Cytoplasmic and Nuclear/metabolism
- Sequence Analysis, DNA
- Sequence Homology, Amino Acid
- T-Box Domain Proteins/genetics
- T-Box Domain Proteins/metabolism
- Zebrafish/embryology
- Zebrafish/genetics
- Zebrafish/metabolism
- Zebrafish Proteins/genetics
- Zebrafish Proteins/metabolism
- Lamin B Receptor
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Affiliation(s)
- Kristina Schild-Prüfert
- Division of Electron Microscopy, Biocenter of the University of Würzburg, Am Hubland, D-97074 Würzburg, Germany
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4
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Hirano Y, Segawa M, Ouchi FS, Yamakawa Y, Furukawa K, Takeyasu K, Horigome T. Dissociation of Emerin from Barrier-to-autointegration Factor Is Regulated through Mitotic Phosphorylation of Emerin in a Xenopus Egg Cell-free System. J Biol Chem 2005; 280:39925-33. [PMID: 16204256 DOI: 10.1074/jbc.m503214200] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Emerin is the gene product of STA whose mutations cause Emery-Dreifuss muscular dystrophy. It is an inner nuclear membrane protein and phosphorylated in a cell cycle-dependent manner. However, the means of phosphorylation of emerin are poorly understood. We investigated the regulation mechanism for the binding of emerin to chromatin, focusing on its cell cycle-dependent phosphorylation in a Xenopus egg cell-free system. It was shown that emerin dissociates from chromatin depending on mitotic phosphorylation of the former, and this plays a critical role in the dissociation of emerin from barrier-to-autointegration factor (BAF). Then, we analyzed the mitotic phosphorylation sites of emerin. Emerin was strongly phosphorylated in an M-phase Xenopus egg cell-free system, and five phosphorylated sites, Ser49, Ser66, Thr67, Ser120, and Ser175, were identified on analysis of chymotryptic and tryptic emerin peptides using a phosphopeptide-concentrating system coupled with a Titansphere column, which specifically binds phosphopeptides, and tandem mass spectrometry sequencing. An in vitro binding assay involving an emerin S175A point mutant protein suggested that phosphorylation at Ser175 regulates the dissociation of emerin from BAF.
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Affiliation(s)
- Yasuhiro Hirano
- Graduate School of Biostudies, Kyoto University, Kitashirakawa-ohiwakecho, Sakyo-ku, Kyoto 606-8205, Japan
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5
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Alpha-Bazin B, Lorphelin A, Nozerand N, Charier G, Marchetti C, Bérenguer F, Couprie J, Gilquin B, Zinn-Justin S, Quéméneur E. Boundaries and physical characterization of a new domain shared between mammalian 53BP1 and yeast Rad9 checkpoint proteins. Protein Sci 2005; 14:1827-39. [PMID: 15987907 PMCID: PMC2253359 DOI: 10.1110/ps.041305205] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Eukaryotic cells have evolved DNA damage checkpoints in response to genome damage. They delay the cell cycle and activate repair mechanisms. The kinases at the heart of these pathways and the accessory proteins, which localize to DNA lesions and regulate kinase activation, are conserved from yeast to mammals. For Saccharomyces cerevisiae Rad9, a key adaptor protein in DNA damage checkpoint pathways, no clear human ortholog has yet been described in mammals. Rad9, however, shares localized homology with both human BRCA1 and 53BP1 since they all contain tandem C-terminal BRCT (BRCA1 C-terminal) motifs. 53BP1 is also a key mediator in DNA damage signaling required for cell cycle arrest, which has just been reported to possess a tandem Tudor repeat upstream of the BRCT motifs. Here we show that the major globular domain upstream of yeast Rad9 BRCT domains is structurally extremely similar to the Tudor domains recently resolved for 53BP1 and SMN. By expressing several fragments encompassing the Tudor-related motif and characterizing them using various physical methods, we isolated the independently folded unit for yeast Rad9. As in 53BP1, the domain corresponds to the SMN Tudor motif plus the contiguous HCA predicted structure region at the C terminus. These domains may help to further elucidate the structural and functional features of these two proteins and improve knowledge of the proteins involved in DNA damage.
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Affiliation(s)
- Béatrice Alpha-Bazin
- Service de Biochimie Post-Génomique et Toxicologie Nucléaire, Direction des Sciences du Vivant (DSV)--Département d'Ingénierie et d'Etudes des Protéines (DIEP), Commissariat à l'Energie Atomique (CEA-VALRHO), Bagnols-sur-Céze, France
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6
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Vayssié L, Vargas M, Weber C, Guillén N. Double-stranded RNA mediates homology-dependant gene silencing of γ-tubulin in the human parasite Entamoeba histolytica. Mol Biochem Parasitol 2004; 138:21-8. [PMID: 15500912 DOI: 10.1016/j.molbiopara.2004.07.005] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2004] [Revised: 07/05/2004] [Accepted: 07/15/2004] [Indexed: 10/26/2022]
Abstract
Approaches that eliminate mRNA are a powerful tool for reverse genetics applications in eukaryotic microbes for which gene replacement techniques have not yet been developed. Here, for the first time, we demonstrate that RNA duplexes efficiently inhibit gene expression when introduced into the human parasite Entamoeba histolytica. Chemically synthesized, small interfering RNA (siRNA) were highly specific and efficient in silencing parasite gamma-tubulin mRNA. Use of specific antibodies revealed that microtubules and gamma-tubulin were intra-nuclear in E. histolytica. The RNAi approach to modulation of gamma-tubulin mRNA resulted in loss of the highly organized microtubule array an observation that correlates with a significant reduction of gamma-tubulin as well as of the specific mRNA. Our results suggest that gamma-tubulin is essential for microtubule nucleation in E. histolytica.
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Affiliation(s)
- Laurence Vayssié
- Unité Biologie Cellulaire du Parasitisme, Institut National de la Santé et de la Recherche Médicale U389, Institut Pasteur, 28 rue du Dr Roux, 75724 Paris Cedex 15, France
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7
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Wagner N, Weber D, Seitz S, Krohne G. The lamin B receptor of Drosophila melanogaster. J Cell Sci 2004; 117:2015-28. [PMID: 15054108 DOI: 10.1242/jcs.01052] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The lamin B receptor (LBR) is an integral membrane protein of the inner nuclear membrane that has so far been characterized only in vertebrates. Here, we describe the Drosophila melanogaster protein encoded by the annotated gene CG17952 that is the putative ortholog to the vertebrate LBR. The Drosophila lamin B receptor (dLBR) has the following properties in common with the vertebrate LBR. First, structure predictions indicate that the 741 amino acid dLBR protein possesses a highly charged N-terminal domain of 307 amino acids followed by eight transmembrane segments in the C-terminal domain of the molecule. Second, immunolocalization and cell fractionation reveal that the dLBR is an integral membrane protein of the inner nuclear membrane. Third, dLBR can be shown by co-immunoprecipitations and in vitro binding assays to bind to the Drosophila B-type lamin Dm0. Fourth, the N-terminal domain of dLBR is sufficient for in vitro binding to sperm chromatin and lamin Dm0. In contrast to the human LBR, dLBR does not possess sterol C14 reductase activity when it is expressed in the Saccharomyces cerevisiae erg24 mutant, which lacks sterol C14 reductase activity. Our data raise the possibility that, during evolution, the enzymatic activity of this insect protein had been lost. To determine whether the dLBR is an essential protein, we depleted it by RNA interference in Drosophila embryos and in cultured S2 and Kc167 cells. There is no obvious effect on the nuclear architecture or viability of treated cells and embryos, whereas the depletion of Drosophila lamin Dm0 in cultured cells and embryos caused morphological alterations of nuclei, nuclear fragility and the arrest of embryonic development. We conclude that dLBR is not a limiting component of the nuclear architecture in Drosophila cells during the first 2 days of development.
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MESH Headings
- Amino Acid Sequence
- Animals
- COS Cells
- Cell Line
- Cell Nucleus/metabolism
- Chromatin/metabolism
- DNA, Complementary/metabolism
- Databases as Topic
- Down-Regulation
- Drosophila Proteins/metabolism
- Drosophila melanogaster
- Electrophoresis, Polyacrylamide Gel
- Fluorescent Antibody Technique, Indirect
- Green Fluorescent Proteins/metabolism
- Humans
- Immunoprecipitation
- Lamins/metabolism
- Lipid Metabolism
- Male
- Mass Spectrometry
- Methionine/chemistry
- Microscopy, Electron
- Microscopy, Fluorescence
- Molecular Sequence Data
- Mutation
- Nuclear Envelope/metabolism
- Oxidoreductases/metabolism
- Plasmids/metabolism
- Protein Binding
- Protein Biosynthesis
- Protein Structure, Tertiary
- RNA Interference
- RNA, Double-Stranded/chemistry
- Receptors, Cytoplasmic and Nuclear/chemistry
- Receptors, Cytoplasmic and Nuclear/metabolism
- Saccharomyces cerevisiae/metabolism
- Sequence Analysis, DNA
- Sequence Homology, Amino Acid
- Spermatozoa/metabolism
- Sterols/metabolism
- Subcellular Fractions/metabolism
- Xenopus
- Lamin B Receptor
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Affiliation(s)
- Nicole Wagner
- Division of Electron Microscopy, Biocenter of the University of Würzburg, Am Hubland, 97074 Würzburg, Germany
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8
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Reichart B, Klafke R, Dreger C, Krüger E, Motsch I, Ewald A, Schäfer J, Reichmann H, Müller CR, Dabauvalle MC. Expression and localization of nuclear proteins in autosomal-dominant Emery-Dreifuss muscular dystrophy with LMNA R377H mutation. BMC Cell Biol 2004; 5:12. [PMID: 15053843 PMCID: PMC407848 DOI: 10.1186/1471-2121-5-12] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2003] [Accepted: 03/30/2004] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The autosomal dominant form of Emery-Dreifuss muscular dystrophy (AD-EDMD) is caused by mutations in the gene encoding for the lamins A and C (LMNA). Lamins are intermediate filament proteins which form the nuclear lamina underlying the inner nuclear membrane. We have studied the expression and the localization of nuclear envelope proteins in three different cell types and muscle tissue of an AD-EDMD patient carrying a point mutation R377H in the lamin A/C gene. RESULTS Lymphoblastoid cells, skin fibroblasts, primary myoblasts and muscle thin sections were studied by immunocytochemistry and electron microscopy. Cellular levels of A-type lamins were reduced compared to control cells. In contrast, the amount of emerin and lamin B appeared unaltered. Cell synchronization experiments showed that the reduction of the cellular level of A-type lamin was due to instability of lamin A. By electron microscopy, we identified a proportion of nuclei with morphological alterations in lymphoblastoid cells, fibroblasts and mature muscle fibres. Immunofluorescence microscopy showed that a major population of the lamin B receptor (LBR), an inner nuclear membrane protein, was recovered in the cytoplasm in association with the ER. In addition, the intranuclear organization of the active form of RNA polymerase II was markedly different in cells of this AD-EDMD patient. This aberrant intranuclear distribution was specifically observed in muscle cells where the pathology of EDMD predominates. CONCLUSIONS From our results we conclude: Firstly, that structural alterations of the nuclei which are found only in a minor fraction of lymphoblastoid cells and mature muscle fibres are not sufficient to explain the clinical pathology of EDMD; Secondly, that wild type lamin A is required not only for the retention of LBR in the inner nuclear membrane but also for a correct localization of the transcriptionally active RNA pol II in muscle cells. We speculate that a rearrangement of the internal chromatin could lead to muscle-specific disease symptoms by interference with proper mRNA transcription.
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Affiliation(s)
- Beate Reichart
- Department of Cell and Developmental Biology, University of Würzburg, Germany
| | - Ruth Klafke
- Department of Cell and Developmental Biology, University of Würzburg, Germany
| | - Christine Dreger
- Department of Cell Biology, German Cancer Research Center, Heidelberg, Germany
| | - Eleonora Krüger
- Department of Cell and Developmental Biology, University of Würzburg, Germany
| | - Isabell Motsch
- Department of Cell and Developmental Biology, University of Würzburg, Germany
| | - Andrea Ewald
- Department of Cell and Developmental Biology, University of Würzburg, Germany
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9
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Gruenbaum Y, Goldman RD, Meyuhas R, Mills E, Margalit A, Fridkin A, Dayani Y, Prokocimer M, Enosh A. The nuclear lamina and its functions in the nucleus. INTERNATIONAL REVIEW OF CYTOLOGY 2004; 226:1-62. [PMID: 12921235 DOI: 10.1016/s0074-7696(03)01001-5] [Citation(s) in RCA: 173] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
The nuclear lamina is a structure near the inner nuclear membrane and the peripheral chromatin. It is composed of lamins, which are also present in the nuclear interior, and lamin-associated proteins. The increasing number of proteins that interact with lamins and the compound interactions between these proteins and chromatin-associated proteins make the nuclear lamina a highly complex but also a very exciting structure. The nuclear lamina is an essential component of metazoan cells. It is involved in most nuclear activities including DNA replication, RNA transcription, nuclear and chromatin organization, cell cycle regulation, cell development and differentiation, nuclear migration, and apoptosis. Specific mutations in nuclear lamina genes cause a wide range of heritable human diseases. These diseases include Emery-Dreifuss muscular dystrophy, limb girdle muscular dystrophy, dilated cardiomyopathy (DCM) with conduction system disease, familial partial lipodystrophy (FPLD), autosomal recessive axonal neuropathy (Charcot-Marie-Tooth disorder type 2, CMT2), mandibuloacral dysplasia (MAD), Hutchison Gilford Progeria syndrome (HGS), Greenberg Skeletal Dysplasia, and Pelger-Huet anomaly (PHA). Genetic analyses in Caenorhabditis elegans, Drosophila, and mice show new insights into the functions of the nuclear lamina, and recent structural analyses have begun to unravel the molecular structure and assembly of lamins and their associated proteins.
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Affiliation(s)
- Yosef Gruenbaum
- Department of Genetics, The Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem 91904, Israel
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10
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Iwabuchi K, Basu BP, Kysela B, Kurihara T, Shibata M, Guan D, Cao Y, Hamada T, Imamura K, Jeggo PA, Date T, Doherty AJ. Potential role for 53BP1 in DNA end-joining repair through direct interaction with DNA. J Biol Chem 2003; 278:36487-95. [PMID: 12824158 DOI: 10.1074/jbc.m304066200] [Citation(s) in RCA: 124] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Upon DNA damage, p53-binding protein 1 (53BP1) relocalizes to sites of DNA double-strand breaks and forms discrete nuclear foci, suggesting its role in DNA damage responses. We show that 53BP1 changed its localization from the detergent soluble to insoluble fraction after treatment of cells with x-ray, but not with ultraviolet or hydroxyurea. Either DNase or phosphatase treatment of the insoluble fraction released 53BP1 into the soluble fraction, showing that 53BP1 binds to chromatin in a phosphorylation-dependent manner after X-irradiation of cells. 53BP1 was retained at discrete nuclear foci in X-irradiated cells even after detergent extraction of cells, showing that the chromatin binding of 53BP1 occurs at sites of DNA double-strand breaks. The minimal domain for focus formation was identified by immunofluorescence staining of cells ectopically expressed with 53BP1 deletion mutants. This domain consisted of conserved Tudor and Myb motifs. The Tudor plus Myb domain possessed chromatin binding activity in vivo and bound directly to both double-stranded and single-stranded DNA in vitro. This domain also stimulated end-joining by DNA ligase IV/Xrcc4, but not by T4 DNA ligase in vitro. We conclude that 53BP1 has the potential to participate directly in the repair of DNA double-strand breaks.
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Affiliation(s)
- Kuniyoshi Iwabuchi
- Department of Biochemistry, Kanazawa Medical University, 1-1 Daigaku, Uchinada, Kahoku-gun, Ishikawa 920-0293, Japan
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11
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Nakagawa T, Hirano Y, Inomata A, Yokota S, Miyachi K, Kaneda M, Umeda M, Furukawa K, Omata S, Horigome T. Participation of a fusogenic protein, glyceraldehyde-3-phosphate dehydrogenase, in nuclear membrane assembly. J Biol Chem 2003; 278:20395-404. [PMID: 12651855 DOI: 10.1074/jbc.m210824200] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
We found an autoimmune serum, K199, that strongly suppresses nuclear membrane assembly in a cell-free system involving a Xenopus egg extract. Four different antibodies that suppress nuclear assembly were affinity-purified from the serum using Xenopus egg cytosol proteins. Three proteins recognized by these antibodies were identified by partial amino acid sequencing to be glyceraldehyde-3-phosphate dehydrogenase (GAPDH), fructose-1,6-bisphosphate aldolase, and the regulator of chromatin condensation 1. GAPDH is known to be a fusogenic protein. To verify the participation of GAPDH in nuclear membrane fusion, authentic antibodies against human and rat GAPDH were applied, and strong suppression of nuclear assembly at the nuclear membrane fusion step was observed. The nuclear assembly activity suppressed by antibodies was recovered on the addition of purified chicken GAPDH. A peptide with the sequence of amino acid residues 70-94 of GAPDH, which inhibits GAPDH-induced phospholipid vesicle fusion, inhibited nuclear assembly at the nuclear membrane fusion step. We propose that GAPDH plays a crucial role in the membrane fusion step in nuclear assembly in a Xenopus egg extract cell-free system.
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Affiliation(s)
- Tomoaki Nakagawa
- Course of Functional Biology, Graduate School of Science and Technology, Niigata University, Igarashi-2, Japan
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12
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Miyachi K, Hankins RW, Matsushima H, Kikuchi F, Inomata T, Horigome T, Shibata M, Onozuka Y, Ueno Y, Hashimoto E, Hayashi N, Shibuya A, Amaki S, Miyakawa H. Profile and clinical significance of anti-nuclear envelope antibodies found in patients with primary biliary cirrhosis: a multicenter study. J Autoimmun 2003; 20:247-54. [PMID: 12753810 DOI: 10.1016/s0896-8411(03)00033-7] [Citation(s) in RCA: 75] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Primary biliary cirrhosis (PBC) sera contain antibodies which recognize various nuclear envelope proteins of which antibody against gp210 has been proven to be diagnostic for disease. In contrast, the clinical significance of another nuclear envelope antibody, anti-p62 antibody has not been well investigated. In the present study, we have analyzed anti-nuclear envelope antibodies by indirect immunofluorescence and immunoblot using rat liver nuclear envelope proteins and wheat germ agglutinin-bound fraction. Test sera were obtained from 175 patients with PBC and from 120 controls. Anti-gp210, anti-lamina associated polypeptide 2, anti-lamin B receptor, and anti-p62 complex antibodies were detected with a frequency of 26% (46 of 175), 6% (11 of 175), 9% (16 of 175), and 13% (15 of 115), respectively. The confirmation of Scheuer's stage IV was made with a frequency of 27% (4 of 15) in PBC patients with anti-p62 complex antibody, in contrast to only 2% (2 of 100) in PBC patients without anti-p62 complex antibody. This difference was found to be statistically significant. The presence of anti-p62 complex antibody may be related with the progressive or advanced state of PBC.
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Affiliation(s)
- Kiyomitsu Miyachi
- First Diagnostic Division, Health Sciences Research Institute Inc, 106 Godo-cho Hodogaya-ku, Yokohama-shi, Kanagawa 240-0005, Japan.
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13
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Takano M, Takeuchi M, Ito H, Furukawa K, Sugimoto K, Omata S, Horigome T. The binding of lamin B receptor to chromatin is regulated by phosphorylation in the RS region. EUROPEAN JOURNAL OF BIOCHEMISTRY 2002; 269:943-53. [PMID: 11846796 DOI: 10.1046/j.0014-2956.2001.02730.x] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Binding of lamin B receptor (LBR) to chromatin was studied by means of an in vitro assay system involving recombinant fragments of human LBR and Xenopus sperm chromatin. Glutathione-S-transferase (GST)-fused proteins including LBR fragments containing the N-terminal region (residues 1-53) and arginine-serine repeat-containing region (residues 54-89) bound to chromatin. The binding of GST-fusion proteins incorporating the N-terminal and arginine-serine repeat-containing regions to chromatin was suppressed by mild trypsinization of the chromatin and by pretreatment with a DNA solution. A new cell-free system for analyzing the cell cycle-dependent binding of a protein to chromatin was developed from recombinant proteins, a Xenopus egg cytosol fraction and sperm chromatin. The system was applied to analyse the binding of LBR to chromatin. It was shown that the binding of LBR fragments to chromatin was stimulated by phosphorylation in the arginine-serine repeat-containing region by a protein kinase(s) in a synthetic phase egg cytosol. However, the binding of LBR fragments was suppressed by phosphorylation at different residues in the same region by a kinase(s) in a mitotic phase cytosol. These results suggested that the cell cycle-dependent binding of LBR to chromatin is regulated by phosphorylation in the arginine-serine repeat-containing region by multiple kinases.
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Affiliation(s)
- Makoto Takano
- Course of Biosphere Science, Graduate School of Science and Technology, Niigata University, Japan
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Duband-Goulet I, Courvalin JC. Inner nuclear membrane protein LBR preferentially interacts with DNA secondary structures and nucleosomal linker. Biochemistry 2000; 39:6483-8. [PMID: 10828963 DOI: 10.1021/bi992908b] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The lamin B receptor (LBR) is an integral protein of inner nuclear membrane whose nucleoplasmic amino-terminal domain contributes to the attachment of the membrane to chromatin. Here we analyzed the interactions of a recombinant GST protein containing the amino-terminal domain of the protein with in vitro reconstituted nucleosomes and short DNA fragments. Data show that the LBR amino-terminal domain (AT) binds linker DNA but does not interact with the nucleosome core. Titration and competition studies revealed that the interaction between LBR AT and DNA is saturable, of high affinity (K(D) approximately 4 nM), independent of DNA sequence, and enhanced by DNA curvature and supercoiling. In this respect, LBR amino-terminal domain binding to nucleosomes is similar to that of histone H1 and non histone proteins HMG1/2 which both bind preferentially to linker DNA and present a significant affinity for DNA secondary structures.
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Affiliation(s)
- I Duband-Goulet
- Département de Biologie Cellulaire Institut Jacques Monod, CNRS, Universités Paris VII-Paris VI, Paris, France.
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Haraguchi T, Koujin T, Hayakawa T, Kaneda T, Tsutsumi C, Imamoto N, Akazawa C, Sukegawa J, Yoneda Y, Hiraoka Y. Live fluorescence imaging reveals early recruitment of emerin, LBR, RanBP2, and Nup153 to reforming functional nuclear envelopes. J Cell Sci 2000; 113 ( Pt 5):779-94. [PMID: 10671368 DOI: 10.1242/jcs.113.5.779] [Citation(s) in RCA: 137] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We determined the times when the nuclear membrane, nuclear pore complex (NPC) components, and nuclear import function were recovered during telophase in living HeLa cells. Simultaneous observation of fluorescently-labeled NLS-bearing proteins, lamin B receptor (LBR)-GFP, and Hoechst33342-stained chromosomes revealed that nuclear membranes reassembled around chromosomes by 5 minutes after the onset of anaphase (early telophase) whereas nuclear import function was recovered later, at 8 minutes. GFP-tagged emerin also accumulated on chromosomes 5 minutes after the onset of anaphase. Interestingly, emerin and LBR initially accumulated at distinct, separate locations, but then became uniform 8 minutes after the onset of anaphase, concurrent with the recovery of nuclear import function. We further determined the timing of NPC assembly by immunofluorescence staining of cells fixed at precise times after the onset of anaphase. Taken together, these results showed that emerin, LBR, and several NPC components (RanBP2, Nup153, p62), but not Tpr, reconstitute around chromosomes very early in telophase prior to the recovery of nuclear import activity.
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Affiliation(s)
- T Haraguchi
- Kansai Advanced Research Center, Communications Research Laboratory, CREST Research Project, Japan Science and Technology Corporation, Iwaoka-cho, Nishi-ku, Kobe 651-2492, Japan.
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Lin F, Blake DL, Callebaut I, Skerjanc IS, Holmer L, McBurney MW, Paulin-Levasseur M, Worman HJ. MAN1, an inner nuclear membrane protein that shares the LEM domain with lamina-associated polypeptide 2 and emerin. J Biol Chem 2000; 275:4840-7. [PMID: 10671519 DOI: 10.1074/jbc.275.7.4840] [Citation(s) in RCA: 261] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The "MAN antigens" are polypeptides recognized by autoantibodies from a patient with a collagen vascular disease and localized to the nuclear envelope. We now show that one of the human MAN antigens termed MAN1 is a 82.3-kDa protein with an amino-terminal domain followed by two hydrophobic segments and a carboxyl-terminal tail. The MAN1 gene contains seven protein-coding exons and is assigned to human chromosome 12q14. Its mRNA is approximately 5.5 kilobases and is detected in several different cell types that were examined. Cell extraction experiments show that MAN1 is an integral membrane protein. When expressed in transfected cells, MAN1 is exclusively targeted to the nuclear envelope, consistent with an inner nuclear membrane localization. Protein sequence analysis reveals that MAN1 shares a conserved globular domain of approximately 40 amino acids, which we term the LEM module, with inner nuclear membrane proteins lamina-associated polypeptide 2 and emerin. The LEM module is also present in two proteins of Caenorhabditis elegans. These results show that MAN1 is an integral protein of the inner nuclear membrane that shares the LEM module with other proteins of this subcellular localization.
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Affiliation(s)
- F Lin
- Departments of Medicine and of Anatomy and Cell Biology, College of Physicians and Surgeons, Columbia University, New York, New York 10032, USA
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Gajewski A, Krohne G. Subcellular distribution of the Xenopus p58/lamin B receptor in oocytes and eggs. J Cell Sci 1999; 112 ( Pt 15):2583-96. [PMID: 10393814 DOI: 10.1242/jcs.112.15.2583] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The p58/lamin B receptor of vertebrates is localized in the inner nuclear membrane. Antibodies raised against the bacterially expressed amino-terminal half of Xenopus p58 (Xp58) revealed that in Xenopus oocytes the vast majority of this membrane protein is localized in cytoplasmic membranes. Only very small amounts of p58 not detectable by immunofluorescence microscopy were contained in the oocyte nuclear envelope. In contrast, nuclear membranes of 2-cell stage embryos were successfully stained with p58 antibodies, nuclei reconstituted in vitro in Xenopus egg extracts contained p58, and the nucleoplasmic domain of Xp58 could be specifically bound to sperm chromatin in vitro. One major difference between oocytes and early embryonic cells is that no chromatin is associated with the oocyte inner nuclear membrane whereas the complement of lamins is identical in both cell types. To gain insight into the properties of oocyte p58 we microinjected isolated nuclei of cultured rat cells into the cytoplasm of Xenopus oocytes. The oocyte p58 was detectable by immunofluorescence microscopy within 16-20 hours in the nuclear membrane of rat nuclei. Our data indicate that the peripheral chromatin but not lamins are required for the retention of p58 in the inner nuclear membrane. Sucrose step gradient centrifugation of total oocyte membranes revealed that the oocyte p58 was predominantly recovered in membrane fractions that did not contain lamins whereas membrane associated lamins and p58 of unfertilized eggs were found in the same fractions. By electron microscopical immunolocalizations one major population of meiotic p58 vesicles was identified that contained exclusively p58 and a second minor population (ca. 11% of p58 vesicles) contained in addition to p58 membrane bound B-type lamins. Egg vesicles containing pore membrane proteins were predominantly recovered in gradient fractions that did not contain p58 and B-type lamins. Our data indicate that the targeting of p58 to chromatin at the end of mitosis in the early Xenopus embryo is a process independent from that of lamin targeting. Comparable to the situation in oocytes and eggs, a significant proportion of p58 of interphase cells could be recovered in fractions that did not contain lamins. This population of p58 molecules could be extracted from A6-cells with buffers containing 1% Triton X-100/0.15 M NaCl and could be pelleted by a 50,000 g centrifugation. A- and B-type lamins were not detectable in the p58 containing pellet.
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Affiliation(s)
- A Gajewski
- Division of Electron Microscopy, Biocenter of the University of Würzburg, Am Hubland, D-97074 Würzburg, Germany
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Abstract
The nuclear envelope is crucial for the functional organization of the nucleus. Lamin B receptor (LBR) and several lamina-associated proteins (LAPs), residing in the inner membrane, provide attachment sites for chromatin and the nuclear lamina. LAPs and LAP-related proteins are members of a growing family of proteins, whose genes are expressed in a tissue and development specific manner, opening the opportunity for a complex regulation of membrane-chromatin and membrane-lamina interactions. Post-translational modifications of LBR and LAPs are likely to modulate their binding to lamins and chromatin, interactions that need to be dynamic to accommodate nuclear growth in interphase and nuclear envelope disassembly in mitosis. Accumulation of proteins in the inner nuclear membrane is believed to depend on their retention mediated by the interaction with nuclear components such as chromatin and lamins.
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Affiliation(s)
- A Chu
- Department of Physiology, Montreal, Que, Canada
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20
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Abstract
Nuclear lamins are intermediate filament-type proteins that are the major building blocks of the nuclear lamina, a fibrous proteinaceous meshwork underlying the inner nuclear membrane. Lamins can also be localized in the nuclear interior, in a diffuse or spotted pattern. Nuclei assembled in vitro in the absence of lamins are fragile, indicating that lamins mechanically stabilize the cell nucleus. Available evidence also indicates a role for lamins in DNA replication, chromatin organization, spatial arrangement of nuclear pore complexes, nuclear growth, and anchorage of nuclear envelope proteins. In this review we summarize the current state of knowledge on the structure, assembly, and possible functional roles of nuclear lamins, emphasizing the information concerning the ability of nuclear lamins to self-assemble into distinct oligomers and polymers.
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Affiliation(s)
- N Stuurman
- M. E. Müller-Institute for Microscopy at the Biozentrum, University of Basel, Basel, CH-4056, Switzerland
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