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Costantini M, Esposito R, Ruocco N, Caramiello D, Cordella A, Ventola GM, Zupo V. De Novo Assembly of the Genome of the Sea Urchin Paracentrotus lividus (Lamarck 1816). Int J Mol Sci 2024; 25:1685. [PMID: 38338963 PMCID: PMC10855541 DOI: 10.3390/ijms25031685] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2024] [Revised: 01/24/2024] [Accepted: 01/25/2024] [Indexed: 02/12/2024] Open
Abstract
The Mediterranean purple sea urchin Paracentrotus lividus (Lamarck 1816) is a remarkable model system for molecular, evolutionary and cell biology studies, particularly in the field of developmental biology. We sequenced the genome, performed a de novo assembly, and analysed the assembly content. The genome of P. lividus was sequenced using Illumina NextSeq 500 System (Illumina) in a 2 × 150 paired-end format. More than 30,000 open reading frames (ORFs), (more than 8000 are unique), were identified and analysed to provide molecular tools accessible for the scientific community. In particular, several genes involved in complex innate immune responses, oxidative metabolism, signal transduction, and kinome, as well as genes regulating the membrane receptors, were identified in the P. lividus genome. In this way, the employment of the Mediterranean sea urchin for investigations and comparative analyses was empowered, leading to the explanation of cis-regulatory networks and their evolution in a key developmental model occupying an important evolutionary position with respect to vertebrates and humans.
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Affiliation(s)
- Maria Costantini
- Stazione Zoologica Anton Dohrn, Department of Ecosustainable Marine Biotechnology, Via Ammiraglio Ferdinando Acton n. 55, 80133 Napoli, Italy;
| | - Roberta Esposito
- Stazione Zoologica Anton Dohrn, Department of Ecosustainable Marine Biotechnology, Via Ammiraglio Ferdinando Acton n. 55, 80133 Napoli, Italy;
| | - Nadia Ruocco
- Stazione Zoologica Anton Dohrn, Department of Ecosustainable Marine Biotechnology, Calabria Marine Centre, C.da Torre Spaccata, 87071 Amendolara, Italy;
| | - Davide Caramiello
- Stazione Zoologica Anton Dohrn, Department of Marine Animal Conservation and Public Engagement, Villa Comunale, 1, 80121 Naples, Italy;
| | - Angela Cordella
- Genomix4Life S.r.l., Baronissi, 84081 Salerno, Italy; (A.C.); (G.M.V.)
- Genome Research Center for Health-CRGS, Baronissi, 84081 Salerno, Italy
| | | | - Valerio Zupo
- Stazione Zoologica Anton Dohrn, Department of Ecosustainable Marine Biotechnology, Ischia Marine Centre, 80121 Naples, Italy
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2
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Schellhaus AK, De Magistris P, Antonin W. Nuclear Reformation at the End of Mitosis. J Mol Biol 2015; 428:1962-85. [PMID: 26423234 DOI: 10.1016/j.jmb.2015.09.016] [Citation(s) in RCA: 58] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2015] [Revised: 09/17/2015] [Accepted: 09/19/2015] [Indexed: 12/17/2022]
Abstract
Cells have developed highly sophisticated ways to accurately pass on their genetic information to the daughter cells. In animal cells, which undergo open mitosis, the nuclear envelope breaks down at the beginning of mitosis and the chromatin massively condenses to be captured and segregated by the mitotic spindle. These events have to be reverted in order to allow the reformation of a nucleus competent for DNA transcription and replication, as well as all other nuclear processes occurring in interphase. Here, we summarize our current knowledge of how, in animal cells, the highly compacted mitotic chromosomes are decondensed at the end of mitosis and how a nuclear envelope, including functional nuclear pore complexes, reassembles around these decondensing chromosomes.
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Affiliation(s)
| | - Paola De Magistris
- Friedrich Miescher Laboratory of the Max Planck Society, Spemannstrasse 39, 72076 Tübingen, Germany
| | - Wolfram Antonin
- Friedrich Miescher Laboratory of the Max Planck Society, Spemannstrasse 39, 72076 Tübingen, Germany.
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3
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Clever M, Mimura Y, Funakoshi T, Imamoto N. Regulation and coordination of nuclear envelope and nuclear pore complex assembly. Nucleus 2013; 4:105-14. [PMID: 23412657 PMCID: PMC3621742 DOI: 10.4161/nucl.23796] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
In metazoans with “open” mitosis, cells undergo structural changes involving the complete disassembly of the nuclear envelope (NE). In post-mitosis, the dividing cell faces the difficulty to reassemble NE structures in a highly regulated fashion around separated chromosomes. The de novo formation of nuclear pore complexes (NPCs), which are gateways between the cytoplasm and nucleoplasm across the nuclear membrane, is an archetype of macromolecular assembly and is therefore of special interest. The reformation of a functional NE further involves the reassembly and organization of other NE components, the nuclear membrane and NE proteins, around chromosomes in late mitosis.
Here, we discuss the function of NE components, such as lamins and INM proteins, in NE reformation and highlight recent results on coordination of NPC and NE assembly.
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Affiliation(s)
- Michaela Clever
- Cellular Dynamics Laboratory, RIKEN Advanced Science Institute 2-1 Hirosawa, Wako, Japan
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4
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Building a nuclear envelope at the end of mitosis: coordinating membrane reorganization, nuclear pore complex assembly, and chromatin de-condensation. Chromosoma 2012; 121:539-54. [PMID: 23104094 PMCID: PMC3501164 DOI: 10.1007/s00412-012-0388-3] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2012] [Revised: 10/04/2012] [Accepted: 10/04/2012] [Indexed: 12/01/2022]
Abstract
The metazoan nucleus is disassembled and re-built at every mitotic cell division. The nuclear envelope, including nuclear pore complexes, breaks down at the beginning of mitosis to accommodate the capture of massively condensed chromosomes by the spindle apparatus. At the end of mitosis, a nuclear envelope is newly formed around each set of segregating and de-condensing chromatin. We review the current understanding of the membrane restructuring events involved in the formation of the nuclear membrane sheets of the envelope, the mechanisms governing nuclear pore complex assembly and integration in the nascent nuclear membranes, and the regulated coordination of these events with chromatin de-condensation.
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5
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Dynamics of PLCγ and Src family kinase 1 interactions during nuclear envelope formation revealed by FRET-FLIM. PLoS One 2012; 7:e40669. [PMID: 22848394 PMCID: PMC3404105 DOI: 10.1371/journal.pone.0040669] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2012] [Accepted: 06/11/2012] [Indexed: 01/10/2023] Open
Abstract
The nuclear envelope (NE) breaks down and reforms during each mitotic cycle. A similar process happens to the sperm NE following fertilisation. The formation of the NE in both these circumstances involves endoplasmic reticulum membranes enveloping the chromatin, but PLCγ-dependent membrane fusion events are also essential. Here we demonstrate the activation of PLCγ by a Src family kinase (SFK1) during NE assembly. We show by time-resolved FRET for the first time the direct in vivo interaction and temporal regulation of PLCγ and SFK1 in sea urchins. As a prerequisite for protein activation, there is a rapid phosphorylation of PLCγ on its Y783 residue in response to GTP in vitro. This phosphorylation is dependent upon SFK activity; thus Y783 phosphorylation and NE assembly are susceptible to SFK inhibition. Y783 phosphorylation is also observed on the surface of the male pronucleus (MPN) in vivo during NE formation. Together the corroborative in vivo and in vitro data demonstrate the phosphorylation and activation of PLCγ by SFK1 during NE assembly. We discuss the potential generality of such a mechanism.
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6
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Clever M, Funakoshi T, Mimura Y, Takagi M, Imamoto N. The nucleoporin ELYS/Mel28 regulates nuclear envelope subdomain formation in HeLa cells. Nucleus 2012; 3:187-99. [PMID: 22555603 PMCID: PMC3383574 DOI: 10.4161/nucl.19595] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
In open mitosis the nuclear envelope (NE) reassembles at the end of each mitosis. This process involves the reformation of the nuclear pore complex (NPC), the inner and outer nuclear membranes, and the nuclear lamina. In human cells cell cycle-dependent NE subdomains exist, characterized as A-type lamin-rich/NPC-free or B-type lamin-rich/NPC-rich, which are initially formed as core or noncore regions on mitotic chromosomes, respectively. Although postmitotic NE formation has been extensively studied, little is known about the coordination of NPC and NE assembly. Here, we report that the nucleoporin ELYS/Mel28, which is crucial for postmitotic NPC formation, is essential for recruiting the lamin B receptor (LBR) to the chromosomal noncore region. Furthermore, ELYS/Mel28 is responsible for focusing of A-type lamin-binding proteins like emerin, Lap2α and the barrier-to-autointegration factor (BAF) at the chromosomal core region. ELYS/Mel28 biochemically interacts with the LBR in a phosphorylation-dependent manner. Recruitment of the LBR depends on the nucleoporin Nup107, which interacts with ELYS/Mel28 but not on nucleoporin Pom121, suggesting that the specific molecular interactions with ELYS/Mel28 are involved in the NE assembly at the noncore region. The depletion of the LBR affected neither the behavior of emerin nor Lap2α indicating that the recruitment of the LBR to mitotic chromosomes is not involved in formation of the core region. The depletion of ELYS/Mel28 also accelerates the entry into cytokinesis after recruitment of emerin to chromosomes. Our data show that ELYS/Mel28 plays a role in NE subdomain formation in late mitosis.
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Affiliation(s)
- Michaela Clever
- Cellular Dynamics Laboratory; Riken Advanced Science Institute; Saitama, Japan
| | - Tomoko Funakoshi
- Cellular Dynamics Laboratory; Riken Advanced Science Institute; Saitama, Japan
- Live-Cell Molecular Imaging Research Team; Riken Advanced Science Institute; Saitama, Japan
| | - Yasuhiro Mimura
- Cellular Dynamics Laboratory; Riken Advanced Science Institute; Saitama, Japan
| | - Masatoshi Takagi
- Cellular Dynamics Laboratory; Riken Advanced Science Institute; Saitama, Japan
| | - Naoko Imamoto
- Cellular Dynamics Laboratory; Riken Advanced Science Institute; Saitama, Japan
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7
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Tseng LC, Chen RH. Temporal control of nuclear envelope assembly by phosphorylation of lamin B receptor. Mol Biol Cell 2011; 22:3306-17. [PMID: 21795390 PMCID: PMC3172257 DOI: 10.1091/mbc.e11-03-0199] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2011] [Revised: 07/06/2011] [Accepted: 07/18/2011] [Indexed: 01/13/2023] Open
Abstract
The nuclear envelope of metazoans disassembles during mitosis and reforms in late anaphase after sister chromatids have well separated. The coordination of these mitotic events is important for genome stability, yet the temporal control of nuclear envelope reassembly is unknown. Although the steps of nuclear formation have been extensively studied in vitro using the reconstitution system from egg extracts, the temporal control can only be studied in vivo. Here, we use time-lapse microscopy to investigate this process in living HeLa cells. We demonstrate that Cdk1 activity prevents premature nuclear envelope assembly and that phosphorylation of the inner nuclear membrane protein lamin B receptor (LBR) by Cdk1 contributes to the temporal control. We further identify a region in the nucleoplasmic domain of LBR that inhibits premature chromatin binding of the protein. We propose that this inhibitory effect is partly mediated by Cdk1 phosphorylation. Furthermore, we show that the reduced chromatin-binding ability of LBR together with Aurora B activity contributes to nuclear envelope breakdown. Our studies reveal for the first time a mechanism that controls the timing of nuclear envelope reassembly through modification of an integral nuclear membrane protein.
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Affiliation(s)
- Li-Chuan Tseng
- Graduate Institute of Life Sciences, National Defense Medical Center, Taipei 114, Taiwan
| | - Rey-Huei Chen
- Graduate Institute of Life Sciences, National Defense Medical Center, Taipei 114, Taiwan
- Institute of Molecular Biology, Academia Sinica, Taipei 11529, Taiwan
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8
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Evans DE, Shvedunova M, Graumann K. The nuclear envelope in the plant cell cycle: structure, function and regulation. ANNALS OF BOTANY 2011; 107:1111-8. [PMID: 21239406 PMCID: PMC3091801 DOI: 10.1093/aob/mcq268] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/15/2010] [Revised: 11/30/2010] [Accepted: 12/03/2010] [Indexed: 05/03/2023]
Abstract
BACKGROUND Higher plants are, like animals, organisms in which successful completion of the cell cycle requires the breakdown and reformation of the nuclear envelope in a highly controlled manner. Interestingly, however, while the structures and processes appear similar, there are remarkable differences in protein composition and function between plants and animals. SCOPE Recent characterization of integral and associated components of the plant nuclear envelope has been instrumental in understanding its functions and behaviour. It is clear that protein interactions at the nuclear envelope are central to many processes in interphase and dividing cells and that the nuclear envelope has a key role in structural and regulatory events. CONCLUSION Dissecting the mechanisms of nuclear envelope breakdown and reformation in plants is necessary before a better understanding of the functions of nuclear envelope components during the cell cycle can be gained.
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Affiliation(s)
| | | | - K. Graumann
- School of Life Sciences, Oxford Brookes University, Oxford OX3 0BP, UK
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9
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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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10
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Abstract
The nuclear envelope (NE) is a highly regulated membrane barrier that separates the nucleus from the cytoplasm in eukaryotic cells. It contains a large number of different proteins that have been implicated in chromatin organization and gene regulation. Although the nuclear membrane enables complex levels of gene expression, it also poses a challenge when it comes to cell division. To allow access of the mitotic spindle to chromatin, the nucleus of metazoans must completely disassemble during mitosis, generating the need to re-establish the nuclear compartment at the end of each cell division. Here, I summarize our current understanding of the dynamic remodeling of the NE during the cell cycle.
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Affiliation(s)
- Martin W Hetzer
- Salk Institute for Biological Studies, Molecular and Cell Biology Laboratory, La Jolla, California 92037, USA.
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11
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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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12
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Abstract
During mitosis in metazoans, the nuclear envelope (NE) breaks down at prophase and reassembles at telophase. The regulation of NE assembly is essential to correct cell functioning. The complex issue of the regulation of NE formation remains to be solved. It is still uncertain that a single mechanism depicts NE formation during mitosis. The aim of this review is to address some of the cytological, biophysical, and molecular aspects of models of NE formation. Our emphasis is on the role of lipids and their modifying enzymes in envelope assembly. We consider how the NE can be used as a model in characterizing membrane dynamics during membrane fusion. Fusion mechanisms that give insight into the formation of the double membrane of the envelope are summarized. We speculate on the possible roles of phosphoinositides in membrane fusion and NE formation.
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Affiliation(s)
- Banafshé Larijani
- Lincoln's Inn Fields Laboratories, Cancer Research UK, London WC2A 3PX, UK.
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13
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Hirano Y, Iwase Y, Ishii K, Kumeta M, Horigome T, Takeyasu K. Cell cycle-dependent phosphorylation of MAN1. Biochemistry 2009; 48:1636-43. [PMID: 19166343 DOI: 10.1021/bi802060v] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
The LEM (LAP2beta, Emerin, and MAN1) proteins are essential for nuclear membrane targeting to chromatin via an association with barrier-to-autointegration factor (BAF). Herein, we focused on the mitotic phosphorylation of MAN1 and its biological role. MAN1 was phosphorylated in a cell cycle-dependent manner in the Xenopus egg cell-free system, and the mitotic phosphorylation at the N-terminal region of MAN1 suppressed the binding of MAN1 to BAF. Titansphere column chromatography followed by MS/MS sequencing identified at least three M-phase-specific phosphorylation sites, Thr-209, Ser-351, and Ser-402, and one cell cycle-independent phosphorylation site, Ser-463. An in vitro BAF binding assay involving mutants S402A and S402E suggested that the phosphorylation of Ser-402 was important for regulation of the binding of MAN1 to BAF.
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Affiliation(s)
- Yasuhiro Hirano
- Graduate School of Biostudies, Kyoto University, Yoshida-konoe-cho, Sakyo-ku, Kyoto 606-8501, Japan.
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14
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Orchestrating nuclear envelope disassembly and reassembly during mitosis. Nat Rev Mol Cell Biol 2009; 10:178-91. [PMID: 19234477 DOI: 10.1038/nrm2641] [Citation(s) in RCA: 347] [Impact Index Per Article: 23.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Cell division in eukaryotes requires extensive architectural changes of the nuclear envelope (NE) to ensure that segregated DNA is finally enclosed in a single cell nucleus in each daughter cell. Higher eukaryotic cells have evolved 'open' mitosis, the most extreme mechanism to solve the problem of nuclear division, in which the NE is initially completely disassembled and then reassembled in coordination with DNA segregation. Recent progress in the field has now started to uncover mechanistic and molecular details that underlie the changes in NE reorganization during open mitosis. These studies reveal a tight interplay between NE components and the mitotic machinery.
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15
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Byrne RD, Poccia DL, Larijani B. Role of phospholipase C in nuclear envelope assembly. ACTA ACUST UNITED AC 2009. [DOI: 10.2217/17584299.4.1.103] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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16
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Garnier-Lhomme M, Byrne RD, Hobday TMC, Gschmeissner S, Woscholski R, Poccia DL, Dufourc EJ, Larijani B. Nuclear envelope remnants: fluid membranes enriched in sterols and polyphosphoinositides. PLoS One 2009; 4:e4255. [PMID: 19165341 PMCID: PMC2626249 DOI: 10.1371/journal.pone.0004255] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2008] [Accepted: 12/23/2008] [Indexed: 11/30/2022] Open
Abstract
Background The cytoplasm of eukaryotic cells is a highly dynamic compartment where membranes readily undergo fission and fusion to reorganize the cytoplasmic architecture, and to import, export and transport various cargos within the cell. The double membrane of the nuclear envelope that surrounds the nucleus, segregates the chromosomes from cytoplasm and regulates nucleocytoplasmic transport through pores. Many details of its formation are still unclear. At fertilization the sperm devoid of nuclear envelope pores enters the egg. Although most of the sperm nuclear envelope disassembles, remnants of the envelope at the acrosomal and centriolar fossae do not and are subsequently incorporated into the newly forming male pronuclear envelope. Remnants are conserved from annelid to mammalian sperm. Methodology/Principal Findings Using lipid mass spectrometry and a new application of deuterium solid-state NMR spectroscopy we have characterized the lipid composition and membrane dynamics of the sperm nuclear envelope remnants in isolated sperm nuclei. Conclusions/Significance We report nuclear envelope remnants are relatively fluid membranes rich in sterols, devoid of sphingomyelin, and highly enriched in polyphosphoinositides and polyunsaturated phospholipids. The localization of the polybasic effector domain of MARCKS illustrates the non-nuclear aspect of the polyphosphoinositides. Based on their atypical biophysical characteristics and phospholipid composition, we suggest a possible role for nuclear envelope remnants in membrane fusion leading to nuclear envelope assembly.
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Affiliation(s)
- Marie Garnier-Lhomme
- Cell Biophysics Laboratory, Lincoln's Inn Fields Laboratories, Cancer Research UK, London, United Kingdom
- Division of Cell and Molecular Biology, Imperial College London, London, United Kingdom
- UMR 5248 CNRS-Université Bordeaux 1-ENITAB, IECB, Pessac, France
| | - Richard D. Byrne
- Cell Biophysics Laboratory, Lincoln's Inn Fields Laboratories, Cancer Research UK, London, United Kingdom
- Department of Biology, Amherst College, Amherst, Massachusetts, United States of America
| | - Tina M. C. Hobday
- Cell Biophysics Laboratory, Lincoln's Inn Fields Laboratories, Cancer Research UK, London, United Kingdom
| | - Stephen Gschmeissner
- Electron Microscopy Unit, Lincoln's Inn Fields Laboratories, Cancer Research UK, London, United Kingdom
| | - Rudiger Woscholski
- Division of Cell and Molecular Biology, Imperial College London, London, United Kingdom
| | - Dominic L. Poccia
- Department of Biology, Amherst College, Amherst, Massachusetts, United States of America
| | - Erick J. Dufourc
- UMR 5248 CNRS-Université Bordeaux 1-ENITAB, IECB, Pessac, France
| | - Banafshé Larijani
- Cell Biophysics Laboratory, Lincoln's Inn Fields Laboratories, Cancer Research UK, London, United Kingdom
- * E-mail:
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17
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Anderson DJ, Hetzer MW. Shaping the endoplasmic reticulum into the nuclear envelope. J Cell Sci 2008; 121:137-42. [PMID: 18187447 DOI: 10.1242/jcs.005777] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
The nuclear envelope (NE), a double membrane enclosing the nucleus of eukaryotic cells, controls the flow of information between the nucleoplasm and the cytoplasm and provides a scaffold for the organization of chromatin and the cytoskeleton. In dividing metazoan cells, the NE breaks down at the onset of mitosis and then reforms around segregated chromosomes to generate the daughter nuclei. Recent data from intact cells and cell-free nuclear assembly systems suggest that the endoplasmic reticulum (ER) is the source of membrane for NE assembly. At the end of mitosis, ER membrane tubules are targeted to chromatin via tubule ends and reorganized into flat nuclear membrane sheets by specific DNA-binding membrane proteins. In contrast to previous models, which proposed vesicle fusion to be the principal mechanism of NE formation, these new studies suggest that the nuclear membrane forms by the chromatin-mediated reshaping of the ER.
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Affiliation(s)
- Daniel J Anderson
- Salk Institute for Biological Studies, Molecular and Cell Biology Laboratory, 10010 N. Torrey Pines Road, La Jolla, CA 92037, USA
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18
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Anderson DJ, Hetzer MW. The life cycle of the metazoan nuclear envelope. Curr Opin Cell Biol 2008; 20:386-92. [PMID: 18495454 DOI: 10.1016/j.ceb.2008.03.016] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2008] [Revised: 03/24/2008] [Accepted: 03/28/2008] [Indexed: 01/12/2023]
Abstract
The nuclear envelope is a double-layered membrane that encloses the nuclear genome and transcriptional machinery. In dividing cells of metazoa, the nucleus completely disassembles during mitosis, creating the need to re-establish the nuclear compartment at the end of each cell division. Given the crucial role of the nuclear envelope in gene regulation and cellular organization, it is not surprising that its biogenesis and organization have become active research areas. We will review recent insights into nuclear membrane dynamics during the cell cycle.
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Affiliation(s)
- Daniel J Anderson
- Salk Institute for Biological Studies, Molecular and Cell Biology Laboratory, 10010 N. Torrey Pines Road, La Jolla, CA 92037, USA
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19
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Vaillant DC, Paulin-Levasseur M. Evaluation of mammalian cell-free systems of nuclear disassembly and assembly. J Histochem Cytochem 2007; 56:157-73. [PMID: 17967934 DOI: 10.1369/jhc.7a7330.2007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Mammalian cell-free systems are very useful for the biochemical and structural study of nuclear disassembly and assembly. Through experimental manipulations, the role of specific proteins in these processes can be studied. Recently, we intended to examine the involvement of integral and peripheral inner nuclear membrane proteins in nuclear disassembly and assembly. However, we could not achieve proper disassembly when isolated interphase HeLa nuclei were exposed to mitotic soluble extracts obtained from the same cell line and containing cyclin B1. Homogenates of synchronized mitotic HeLa cells left to reassemble their nuclei generated incomplete nuclear envelopes on chromatin masses. Digitonin-permeabilized mitotic cells also assembled incomplete nuclei, generating a lot of cytoplasmic inclusions of inner nuclear membrane proteins as an intermediate. These results were therefore used as a basis for a critical evaluation of mammalian cell-free systems. We present here evidence that cell synchronization itself can interfere with the progress of nuclear assembly, possibly by causing aberrant nuclear disassembly and/or by inducing the formation of an abnormal number of mitotic spindles.
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Affiliation(s)
- Dominique C Vaillant
- Department of Biology, University of Ottawa, 30 Marie Curie, Ottawa, Ontario, Canada K1N 6N5
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20
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Ito H, Koyama Y, Takano M, Ishii K, Maeno M, Furukawa K, Horigome T. Nuclear envelope precursor vesicle targeting to chromatin is stimulated by protein phosphatase 1 in Xenopus egg extracts. Exp Cell Res 2007; 313:1897-910. [PMID: 17448463 DOI: 10.1016/j.yexcr.2007.03.015] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2006] [Revised: 03/08/2007] [Accepted: 03/15/2007] [Indexed: 10/23/2022]
Abstract
The mechanism underlying targeting of the nuclear membrane to chromatin at the end of mitosis was studied using an in vitro cell-free system comprising Xenopus egg membrane and cytosol fractions, and sperm chromatin. The mitotic phase membrane, which was separated from a mitotic phase extract of Xenopus eggs and could not bind to chromatin, became able to bind to chromatin on pretreatment with a synthetic phase cytosol fraction of Xenopus eggs. When the cytosol fraction was depleted of protein phosphatase 1 (PP1) with anti-Xenopus PP1gamma1 antibodies, this ability was lost. The addition of recombinant xPP1gamma1 to the PP1-depleted cytosol fraction restored the ability. These and other results suggested that dephosphorylation of mitotic phosphorylation sites on membranes by PP1 in the synthetic phase cytosol fraction promoted targeting of the membranes to chromatin. On the other hand, a fragment containing the chromatin-binding domain of lamin B receptor (LBR) but not emerin inhibited targeting of membrane vesicles. It was also shown that PP1 dephosphorylates a phosphate group(s) responsible for regulation of the binding of LBR to chromatin. A possible mechanism involving PP1 and LBR for the regulation of nuclear membrane targeting to chromatin was discussed.
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Affiliation(s)
- Hiromi Ito
- Courses of Fundamental Sciences, Graduate School of Science and Technology, Niigata University, Igarashi-2, Niigata 950-2181, Japan
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21
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Larijani B, Poccia D. Protein and lipid signaling in membrane fusion: nuclear envelope assembly. ACTA ACUST UNITED AC 2007. [DOI: 10.1002/sita.200600128] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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22
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Byrne RD, Garnier-Lhomme M, Han K, Dowicki M, Michael N, Totty N, Zhendre V, Cho A, Pettitt TR, Wakelam MJ, Poccia DL, Larijani B. PLCgamma is enriched on poly-phosphoinositide-rich vesicles to control nuclear envelope assembly. Cell Signal 2006; 19:913-22. [PMID: 17184973 DOI: 10.1016/j.cellsig.2006.10.011] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2006] [Revised: 10/30/2006] [Accepted: 10/31/2006] [Indexed: 01/07/2023]
Abstract
Nuclear envelope assembly is an essential event in each cell cycle but the proteins and lipids involved in its regulation remain mostly unknown. Assembly involves membrane fusions but neither specific SNAREs nor Rab GTPases have been identified in its control. We report that a precursor membrane population (MV1) required for NE assembly has a unique lipid composition consisting prominently of poly-phosphatidylinositides. The lipid composition was determined by adapting HPLC electrospray ionisation tandem mass spectrometry to phosphoinositide analysis, revealing the capacity of this technique to document dynamic lipid transitions of functional importance in natural membrane populations. MV1 is >100-fold enriched in endogenous PLCgamma and >25-fold enriched in the PLC substrate phosphatidylinositol bisphosphate (PtdInsP2) compared to the second membrane population, derived largely from endoplasmic reticulum (ER), that contributes most of the NE. During NE formation PLCgamma becomes transiently phosphorylated at the tyrosine 783 site indicative of its activation. In addition specific inhibition of PLCgamma blocks nuclear envelope formation. In vivo, PLCgamma is concentrated on vesicles of similar size to purified MV1. These associate with nuclei during the period of NE formation and are distinct from ER membranes. The unprecedented concentration of PLCgamma and its substrate PtdInsP2 in a subset of membranes that binds to only two regions of the nucleus, and activation of PLCgamma by GTP during initial stages of NE formation provide a mechanism for temporal control of NE assembly and offer an explanation for how such a process of membrane fusion can be spatially regulated.
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Affiliation(s)
- Richard D Byrne
- Cell Biophysics Laboratory, Cancer Research UK (CRUK), London Research Institute, 44 Lincoln's Inn Fields, London, WC2A 3PX, UK
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23
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Ulbert S, Antonin W, Platani M, Mattaj IW. The inner nuclear membrane protein Lem2 is critical for normal nuclear envelope morphology. FEBS Lett 2006; 580:6435-41. [PMID: 17097643 DOI: 10.1016/j.febslet.2006.10.060] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2006] [Revised: 10/27/2006] [Accepted: 10/27/2006] [Indexed: 01/16/2023]
Abstract
The inner nuclear membrane (INM) of eukaryotic cells is characterized by a unique set of transmembrane proteins which interact with chromatin and/or the nuclear lamina. The number of identified INM proteins is steadily increasing, mainly as a result of proteomic and computational approaches. However, despite a link between mutation of several of these proteins and disease, the function of most transmembrane proteins of the INM remains unknown and depletion of many of these proteins from a variety of systems did not produce an obvious phenotype in the affected cells. Here, we report that depletion of the conserved INM protein Lem2 from human cell lines leads to abnormally shaped nuclei and severely reduces cell survival. We suggest that interactions of Lem2 with lamins or chromatin are critical for maintaining the integrity of the nuclear envelope.
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Ulbert S, Platani M, Boue S, Mattaj IW. Direct membrane protein-DNA interactions required early in nuclear envelope assembly. ACTA ACUST UNITED AC 2006; 173:469-76. [PMID: 16717124 PMCID: PMC2063857 DOI: 10.1083/jcb.200512078] [Citation(s) in RCA: 86] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Among the earliest events in postmitotic nuclear envelope (NE) assembly are the interactions between chromatin and the membranes that will fuse to form the NE. It has been proposed that interactions between integral NE proteins and chromatin proteins mediate initial membrane recruitment to chromatin. We show that several transmembrane NE proteins bind to DNA directly and that NE membrane proteins as a class are enriched in long, basic domains that potentially bind DNA. Membrane fractions that are essential for NE formation are shown to bind directly to protein-free DNA, and our data suggest that these interactions are critical for early steps in NE assembly.
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Affiliation(s)
- Sebastian Ulbert
- European Molecular Biology Laboratory, 69117 Heidelberg, Germany
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25
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Hetzer MW, Walther TC, Mattaj IW. PUSHING THE ENVELOPE: Structure, Function, and Dynamics of the Nuclear Periphery. Annu Rev Cell Dev Biol 2005; 21:347-80. [PMID: 16212499 DOI: 10.1146/annurev.cellbio.21.090704.151152] [Citation(s) in RCA: 253] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The nuclear envelope (NE) is a highly specialized membrane that delineates the eukaryotic cell nucleus. It is composed of the inner and outer nuclear membranes, nuclear pore complexes (NPCs) and, in metazoa, the lamina. The NE not only regulates the trafficking of macromolecules between nucleoplasm and cytosol but also provides anchoring sites for chromatin and the cytoskeleton. Through these interactions, the NE helps position the nucleus within the cell and chromosomes within the nucleus, thereby regulating the expression of certain genes. The NE is not static, rather it is continuously remodeled during cell division. The most dramatic example of NE reorganization occurs during mitosis in metazoa when the NE undergoes a complete cycle of disassembly and reformation. Despite the importance of the NE for eukaryotic cell life, relatively little is known about its biogenesis or many of its functions. We thus are far from understanding the molecular etiology of a diverse group of NE-associated diseases.
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Affiliation(s)
- Martin W Hetzer
- Molecular and Cell Biology Laboratory, Salk Institute for Biological Studies, La Jolla, California 92037, USA.
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26
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Barona T, Byrne RD, Pettitt TR, Wakelam MJO, Larijani B, Poccia DL. Diacylglycerol induces fusion of nuclear envelope membrane precursor vesicles. J Biol Chem 2005; 280:41171-7. [PMID: 16216883 DOI: 10.1074/jbc.m412863200] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Purified membrane vesicles isolated from sea urchin eggs form nuclear envelopes around sperm nuclei following GTP hydrolysis in the presence of cytosol. A low density subfraction of these vesicles (MV1), highly enriched in phosphatidylinositol (PtdIns), is required for nuclear envelope formation. Membrane fusion of MV1 with a second fraction that contributes most of the nuclear envelope can be initiated without GTP by an exogenous bacterial PtdIns-specific phospholipase C (PI-PLC) which hydrolyzes PtdIns to form diacylglycerides and inositol 1-phosphate. This PI-PLC hydrolyzes a subset of sea urchin membrane vesicle PtdIns into diglycerides enriched in long chain, polyunsaturated species as revealed by a novel liquid chromatography-mass spectrometry analysis. Large unilammelar vesicles (LUVs) enriched in PtdIns can substitute for MV1 in PI-PLC induced nuclear envelope formation. Moreover, MV1 prehydrolyzed with PI-PLC and washed to remove inositols leads to spontaneous nuclear envelope formation with MV2 without further PI-PLC treatment. LUVs enriched in diacylglycerol mimic prehydrolyzed MV1. These results indicate that production of membrane-destabilizing diglycerides in membranes enriched in PtdIns may facilitate membrane fusion in a natural membrane system and suggest that MV1, which binds only to two places on the sperm nucleus, may initiate fusion locally.
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Affiliation(s)
- Teresa Barona
- Biology Department, Amherst College, Amherst, Massachusetts 01002, USA
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27
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Byrne R, Barona T, Garnier M, Koster G, Katan M, Poccia D, Larijani B. Nuclear envelope assembly is promoted by phosphoinositide-specific phospholipase C with selective recruitment of phosphatidylinositol-enriched membranes. Biochem J 2005; 387:393-400. [PMID: 15554872 PMCID: PMC1134967 DOI: 10.1042/bj20040947] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2004] [Revised: 11/10/2004] [Accepted: 11/19/2004] [Indexed: 11/17/2022]
Abstract
Nuclear envelope (NE) formation in a cell-free egg extract proceeds by precursor membrane vesicle binding to chromatin in an ATP-dependent manner, followed by a GTP-induced NE assembly step. The requirement for GTP in the latter step of this process can be mimicked by addition of bacterial PI-PLC [phosphoinositide (PtdIns)-specific phospholipase C]. The NE assembly process is here dissected in relation to the requirement for endogenous phosphoinositide metabolism, employing recombinant eukaryotic PI-PLC, inhibitors and direct phospholipid analysis using ESI-MS (electrospray ionization mass spectrometry). PtdIns (phosphatidylinositol) species analysis by ESI-MS indicates that the chromatin-bound NE precursor vesicles are enriched for specific PtdIns species. Moreover, during GTP-induced precursor vesicle fusion, the membrane vesicles become partially depleted of the PtdIns 18:0/20:4 species. These data indicate that eukaryotic PI-PLC can support NE formation, and the sensitivity to exogenous recombinant PtdIns-5-phosphatases shows that the endogenous PLC hydrolyses a 5-phosphorylated species. It is shown further that the downstream target of this DAG (diacylglycerol) pathway does not involve PKC (protein kinase C) catalytic function, but is mimicked by phorbol esters, indicating a possible engagement of one of the non-PKC phorbol ester receptors. The results show that ESI-MS can be used as a sensitive means to measure the lipid composition of biological membranes and their changes during, for example, membrane fusogenic events. We have exploited this and the intervention studies to illustrate a pivotal role for PI-PLC and its product DAG in the formation of NEs.
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Key Words
- diacylglycerol
- electrospray ionization mass spectrometry
- membrane fusion
- nuclear envelope
- phosphatidylinositol
- phosphoinositide-specific phospholipase c
- atp-gs, atp-generating system
- bapta, bis-(o-aminophenoxy)ethane-n,n,n′,n′-tetra-acetic acid
- dag, 1,2-diacylglycerol
- dioc6, 3,3′-dihexyloxacarbocyanine iodide
- ptdcho, phosphatidylcholine
- dmpc, dimyristoyl-ptdcho
- ptdins, phosphatidylinositol
- dppi, dipalmitoyl-ptdins
- er, endoplasmic reticulum
- esi-ms, electrospray ionization mass spectrometry
- gap, gtpase-activating protein
- gtp[s], guanosine 5′-[γ-thio]triphosphate
- lb, lysis buffer
- mv, membrane vesicle
- ne, nuclear envelope
- pi-plc, phosphoinositide-specific phospholipase c
- pkc, protein kinase c
- snare, soluble n-ethylmaleimide-sensitive fusion protein attachment protein receptor
- sxn, nuclei preparation buffer
- syn1-5ptase, synaptojanin 1 phosphatase
- tn, tris/nacl buffer
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Affiliation(s)
- Richard D. Byrne
- *Cell Biophysics Laboratory, London Research Institute (LRI), Cancer Research UK (CR-UK), 44, Lincoln's Inn Fields, London, WC2A 3PX, U.K
| | - Teresa M. Barona
- †Department of Biology, Amherst College, Amherst, MA 01002, U.S.A
| | - Marie Garnier
- *Cell Biophysics Laboratory, London Research Institute (LRI), Cancer Research UK (CR-UK), 44, Lincoln's Inn Fields, London, WC2A 3PX, U.K
| | - Grielof Koster
- ‡Infection, Inflammation and Repair Division, University of Southampton, Southampton, SO16 6YD, U.K
| | - Matilda Katan
- §Cancer Research UK Centre for Cell and Molecular Biology, Chester Beatty Laboratories, Institute of Cancer Research (ICR), Fulham Rd, London, SW3 6JB, U.K
| | - Dominic L. Poccia
- †Department of Biology, Amherst College, Amherst, MA 01002, U.S.A
- ∥UIBD, Universidade Lusófona, Campo Grande 376, 1749–1024, Lisbon, Portugal
| | - Banafshé Larijani
- *Cell Biophysics Laboratory, London Research Institute (LRI), Cancer Research UK (CR-UK), 44, Lincoln's Inn Fields, London, WC2A 3PX, U.K
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Margalit A, Vlcek S, Gruenbaum Y, Foisner R. Breaking and making of the nuclear envelope. J Cell Biochem 2005; 95:454-65. [PMID: 15832341 DOI: 10.1002/jcb.20433] [Citation(s) in RCA: 83] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
During mitosis, a single nucleus gives rise to two nuclei that are identical to the parent nucleus. Mitosis consists of a continuous sequence of events that must be carried out once and only once. Two such important events are the disassembly of the nuclear envelope (NE) during the first stages of mitosis, and its accurate reassembly during the last stages of mitosis. NE breakdown (NEBD) is initiated when maturation-promoting factor (MPF) enters the nucleus and starts phosphorylating nuclear pore complexes (NPCs) and nuclear lamina proteins, followed by NPC and lamina breakdown. Nuclear reassembly starts when nuclear membranes assemble onto the chromatin. This article focuses on the different models of NEBD and reassembly with emphasis on recent data.
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Affiliation(s)
- Ayelet Margalit
- Department of Genetics, The Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem, Israel
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29
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Makatsori D, Kourmouli N, Polioudaki H, Shultz LD, McLean K, Theodoropoulos PA, Singh PB, Georgatos SD. The inner nuclear membrane protein lamin B receptor forms distinct microdomains and links epigenetically marked chromatin to the nuclear envelope. J Biol Chem 2004; 279:25567-73. [PMID: 15056654 DOI: 10.1074/jbc.m313606200] [Citation(s) in RCA: 115] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Using heterochromatin-enriched fractions, we have detected specific binding of mononucleosomes to the N-terminal domain of the inner nuclear membrane protein lamin B receptor. Mass spectrometric analysis reveals that LBR-associated particles contain complex patterns of methylated/acetylated histones and are devoid of "euchromatic" epigenetic marks. LBR binds heterochromatin as a higher oligomer and forms distinct nuclear envelope microdomains in vivo. The organization of these membrane assemblies is affected significantly in heterozygous ic (ichthyosis) mutants, resulting in a variety of structural abnormalities and nuclear defects.
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Affiliation(s)
- Dimitra Makatsori
- Laboratory of Biology, The University of Ioannina, School of Medicine, 45 110 Ioannina, Greece
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30
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Takano M, Koyama Y, Ito H, Hoshino S, Onogi H, Hagiwara M, Furukawa K, Horigome T. Regulation of binding of lamin B receptor to chromatin by SR protein kinase and cdc2 kinase in Xenopus egg extracts. J Biol Chem 2004; 279:13265-71. [PMID: 14718546 DOI: 10.1074/jbc.m308854200] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Participation of multiple kinases in regulation of the binding of lamin B receptor (LBR) to chromatin was suggested previously (Takano, M., Takeuchi, M., Ito, H., Furukawa, K., Sugimoto, K., Omata, S., and Horigome, T. (2002) Eur. J. Biochem. 269, 943-953). To identify these kinases, regulation of the binding of the nucleoplasmic region (NK, amino acid residues 1-211) of LBR to sperm chromatin was studied using a cell cycle-dependent Xenopus egg extract in vitro. The binding was stimulated on specific phosphorylation of the NK fragment by an S-phase egg extract. Protein depletion with beads bearing SF2/ASF, which binds SR protein kinases, abolished this stimulation, suggesting that an SR protein kinase(s) is responsible for the activation of LBR. This was confirmed by direct phosphorylation and activation with recombinant SR protein-specific kinase 1. The binding of the NK fragment to chromatin pretreated with an S-phase extract was suppressed by incubation with an M-phase extract. Enzyme inhibitor experiments revealed that multiple kinases participate in the suppression. One of these kinases was shown to be cdc2 kinase using a specific inhibitor, roscovitine, and protein depletion with beads bearing p13, which specifically binds cdc2 kinase. Experiments involving a mutant NK fragment showed that the phosphorylation of serine 71 by cdc2 kinase is responsible for the suppression.
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Affiliation(s)
- Makoto Takano
- Course of Biosphere Science, Graduate School of Science and Technology, Faculty of Science, Niigata University, Igarashi-2, Niigata 950-2181, Japan
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31
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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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32
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Lamin-Associated Proteins. Methods Cell Biol 2004. [DOI: 10.1016/s0091-679x(04)78029-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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33
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Courvalin JC, Rabouille C. Réorganisation des compartiments intracellulaires membranaires pendant la mitose. Med Sci (Paris) 2002. [DOI: 10.1051/medsci/200218101017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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34
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Hetzer M, Gruss OJ, Mattaj IW. The Ran GTPase as a marker of chromosome position in spindle formation and nuclear envelope assembly. Nat Cell Biol 2002; 4:E177-84. [PMID: 12105431 DOI: 10.1038/ncb0702-e177] [Citation(s) in RCA: 179] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The small GTPase Ran is a key regulator of nucleocytoplasmic transport during interphase. The asymmetric distribution of the GTP-bound form of Ran across the nuclear envelope--that is, large quantities in the nucleus compared with small quantities in the cytoplasm--determines the directionality of many nuclear transport processes. Recent findings that Ran also functions in spindle formation and nuclear envelope assembly during mitosis suggest that Ran has a general role in chromatin-centred processes. Ran functions in these events as a signal for chromosome position.
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Affiliation(s)
- Martin Hetzer
- European Molecular Biology Laboratory, Meyerhofstrasse 1, 69117 Heidelberg, Germany
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35
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Goldman RD, Gruenbaum Y, Moir RD, Shumaker DK, Spann TP. Nuclear lamins: building blocks of nuclear architecture. Genes Dev 2002; 16:533-47. [PMID: 11877373 DOI: 10.1101/gad.960502] [Citation(s) in RCA: 442] [Impact Index Per Article: 20.1] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Affiliation(s)
- Robert D Goldman
- Northwestern University Medical School, Department of Cell and Molecular Biology, Chicago, Illinois 60611, USA.
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36
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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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37
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Ewald A, Zünkler C, Lourim D, Dabauvalle MC. Microtubule-dependent assembly of the nuclear envelope in Xenopus laevis egg extract. Eur J Cell Biol 2001; 80:678-91. [PMID: 11824787 DOI: 10.1078/0171-9335-00207] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Microtubules take part in several mechanisms of intracellular motility, including organelle transport and mitosis. We have studied the ability of Xenopus egg extract to support nuclear membrane and pore complex formation when microtubule dynamics are manipulated. In this report we show that the formation of a nuclear envelope surrounding sperm chromatin requires polymerized microtubules. We have observed that microtubule-depolymerizing reagents, and AS-2, a known inhibitor of the microtubule motor protein kinesin, do not inhibit the formation of a double nuclear membrane. However these double membranes contain no morphologically identifiable nuclear pore complexes and do not support the accumulation of karyophilic proteins. In contrast, the assembly of annulate lamellae, cytoplasmic structures containing a subset of pore complex proteins, was not affected. Our data show that not only polymerized microtubules, but also the microtubule motor protein kinesin, are involved in the formation of the nuclear envelope. These results support the conclusion that multiple nuclear envelope-forming mitotic vesicle populations exist, that microtubules play an essential and selective role in the transport of nuclear envelope-forming vesicle population(s), and that separate mechanisms are involved in nuclear envelope and annulate lamellae formation.
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Affiliation(s)
- A Ewald
- Department of Cell and Developmental Biology, Theodor-Boveri-Institute, University of Würzburg, Germany
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Landsverk HB, Carlson CR, Steen RL, Vossebein L, Herberg FW, Taskén K, Collas P. Regulation of anchoring of the RIIα regulatory subunit of PKA to AKAP95 by threonine phosphorylation of RIIα: implications for chromosome dynamics at mitosis. J Cell Sci 2001; 114:3255-64. [PMID: 11591814 DOI: 10.1242/jcs.114.18.3255] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
CDK1 phosphorylates the A-kinase regulatory subunit RIIα on threonine 54 (T54) at mitosis, an event proposed to alter the subcellular localization of RIIα. Using an RIIα-deficient leukemic cell line (Reh) and stably transfected Reh cell clones expressing wild-type RIIα or an RIIα(T54E) mutant, we show that RIIα associates with chromatin-bound A-kinase anchoring protein AKAP95 at mitosis and that this interaction involves phosphorylation of RIIα on T54. During interphase, both RIIα and RIIα(T54E) exhibit a centrosome-Golgi localization, whereas AKAP95 is intranuclear. At mitosis and in a mitotic extract, most RIIα, but not RIIα(T54E), co-fractionates with chromatin, onto which it associates with AKAP95. This correlates with T54 phosphorylation of RIIα. Disrupting AKAP95-RIIα anchoring or depleting RIIα from the mitotic extract promotes premature chromatin decondensation. In a nuclear reconstitution assay that mimics mitotic nuclear reformation, RIIα is threonine dephosphorylated and dissociates from AKAP95 prior to assembly of nuclear membranes. Lastly, the Reh cell line exhibits premature chromatin decondensation in vitro, which can be rescued by addition of wild-type RIIα or an RIIα(T54D) mutant, but not RIIα(T54E, A, L or V) mutants. Our results suggest that CDK1-mediated T54 phosphorylation of RIIα constitutes a molecular switch controlling anchoring of RIIα to chromatin-bound AKAP95, where the PKA-AKAP95 complex participates in remodeling chromatin during mitosis.
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Affiliation(s)
- H B Landsverk
- Institute of Medical Biochemistry, Faculty of Medicine, University of Oslo, PO Box 1112 Blindern, 0317 Oslo, Norway
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Carlson CR, Witczak O, Vossebein L, Labbé JC, Skålhegg BS, Keryer G, Herberg FW, Collas P, Taskén K. CDK1-mediated phosphorylation of the RIIα regulatory subunit of PKA works as a molecular switch that promotes dissociation of RIIα from centrosomes at mitosis. J Cell Sci 2001; 114:3243-54. [PMID: 11591813 DOI: 10.1242/jcs.114.18.3243] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Protein kinase A regulatory subunit RIIα is tightly bound to centrosomal structures during interphase through interaction with the A-kinase anchoring protein AKAP450, but dissociates and redistributes from centrosomes at mitosis. The cyclin B-p34cdc2 kinase (CDK1) has been shown to phosphorylate RIIα on T54 and this has been proposed to alter the subcellular localization of RIIα. We have made stable transfectants from an RIIα-deficient leukemia cell line (Reh) that expresses either wild-type or mutant RIIα (RIIα(T54E)). When expressed, RIIα detaches from centrosomes at mitosis and dissociates from its centrosomal location in purified nucleus-centrosome complexes by incubation with CDK1 in vitro. By contrast, centrosomal RIIα(T54E) is not redistributed at mitosis, remains mostly associated with centrosomes during all phases of the cell cycle and cannot be solubilized by CDK1 in vitro. Furthermore, RIIα is solubilized from particular cell fractions and changes affinity for AKAP450 in the presence of CDK1. D and V mutations of T54 also reduce affinity for the N-terminal RII-binding domain of AKAP450, whereas small neutral residues do not change affinity detected by surface plasmon resonance. In addition, only RIIα(T54E) interacts with AKAP450 in a RIPA-soluble extract from mitotic cells. Finally, microtubule repolymerization from mitotic centrosomes of the RIIα(T54E) transfectant is poorer and occurs at a lower frequency than that of RIIα transfectants. Our results suggest that T54 phosphorylation of RIIα by CDK1 might serve to regulate the centrosomal association of PKA during the cell cycle.
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Affiliation(s)
- C R Carlson
- Institute of Medical Biochemistry, University of Oslo, PO Box 1112 Blindern, N-0317 Oslo, Norway.
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Taskén KA, Collas P, Kemmner WA, Witczak O, Conti M, Taskén K. Phosphodiesterase 4D and protein kinase a type II constitute a signaling unit in the centrosomal area. J Biol Chem 2001; 276:21999-2002. [PMID: 11285255 DOI: 10.1074/jbc.c000911200] [Citation(s) in RCA: 183] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The mediation of cAMP effects by specific pools of protein kinase A (PKA) targeted to distinct subcellular domains raises the question of how inactivation of the cAMP signal is achieved locally and whether similar targeting of phosphodiesterases (PDEs) to sites of cAMP/PKA action could be observed. Here, we demonstrate that Sertoli cells of the testis contain an insoluble PDE4D3 isoform, which is shown by immunofluorescence to target to centrosomes. Staining of PDE4D and PKA shows co-localization of PDE4D with PKA-RIIalpha and RIIbeta in the centrosomal region. Co-precipitation of RII subunits and PDE4D3 from cytoskeletal extracts indicates a physical association of the two proteins. Distribution of PDE4D overlaps with that of the centrosomal PKA-anchoring protein, AKAP450, and AKAP450, PDE4D3, and PKA-RIIalpha co-immunoprecipitate. Finally, both PDE4D3 and PKA co-precipitate with a soluble fragment of AKAP450 encompassing amino acids 1710 to 2872 when co-expressed in 293T cells. Thus, a centrosomal complex that includes PDE4D and PKA constitutes a novel signaling unit that may provide accurate spatio-temporal modulation of cAMP signals.
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Affiliation(s)
- K A Taskén
- Institute of Medical Biochemistry, University of Oslo, N-0317 Oslo, Norway
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41
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Affiliation(s)
- S D Georgatos
- Department of Basic Sciences, The University of Crete, School of Medicine, Stavrakia, 71 110 Heraklion, Crete, Greece.
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42
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Dahle MK, Reinton N, Orstavik S, Taskén KA, Taskén K. Novel alternatively spliced mRNA (1c) of the protein kinase A RIα subunit is implicated in haploid germ cell specific expression. Mol Reprod Dev 2001; 59:11-6. [PMID: 11335941 DOI: 10.1002/mrd.1001] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
By using 5' RACE on rat testis cDNA we identified three alternatively spliced mRNAs of the RIalpha subunit of cAMP-dependent protein kinase that differed in their 5' untranslated regions. Two of these 5'-regions showed similarity with the human RIalpha exons 1a and 1b, while the third (1c) constituted a novel mRNA splice variant. Northern blot analysis showed that the 1c mRNA was specifically expressed in testis and only in postmeiotic germ cells. In contrast, the RIalpha 1b and RIalpha 1a mRNAs were present both in premeiotic germ cells and somatic cells of the testis, and the expression of both RIalpha 1a and 1b mRNAs were stimulated by cAMP in Sertoli cells. In sperm, the RIalpha protein was expressed after meiosis, and targeted to various subcellular structures via anchoring proteins. The RIalpha 1c haploid-specific mRNA, therefore, may be important for the regulation of RIalpha expression in sperm.
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Affiliation(s)
- M K Dahle
- Institute of Medical Biochemistry, University of Oslo, Oslo, Norway.
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Abstract
The presence and organization of intermediate filament (IF) proteins in petaloid coelomocytes from two species of echinoderms, the sea urchin Strongylocentrotus droehachiensis and the sea cucumber Cucumaria frondosa, were studied. Two monoclonal antibodies (IFA and Ah6) and one polyclonal antibody (W3-1) that together recognize invertebrate as well as vertebrate IF proteins were used to probe coelomocytes by immunofluorescence and immunoblotting methods. All three antibodies cross-reacted with a single Mr 68,000 sea urchin lamin, as well as two putative lamin isoforms of approximately Mr 70,000 and 68,000 in sea cucumber coelomocytes. Both IFA and Ah6 labeled granular material in the cytoplasm of sea urchin coelomocytes; by contrast, IFA labeling revealed a striking network of reticular material irregularly arrayed within the central regions of the sea cucumber coelomocyte cytoplasm. In addition, foci of Ah6-positive material were present in coelomocyte nuclei from both species. Comparison of immunoblotting patterns among whole cell and isolated nuclear preparations suggest that the cytoplasmic IF-like material is composed of Mr 46,000 and 58,000 polypeptides, while Mr 215,000 and 185,000 proteins are candidates for the immunoreactive nuclear foci. Further study of the functions of these non-filamentous arrays of IF proteins may furnish valuable insights into the evolution of IF function within vertebrate cells, particularly with respect to certain cytoplasmic and nuclear regulatory functions with which IF proteins have been speculated to be involved.
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Affiliation(s)
- J Holy
- Department of Anatomy and Cell Biology, School of Medicine, University of Minnesota, Duluth 55812-2487, USA.
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Martins SB, Eide T, Steen RL, Jahnsen T, Skålhegg B S, Collas P. HA95 is a protein of the chromatin and nuclear matrix regulating nuclear envelope dynamics. J Cell Sci 2000; 113 Pt 21:3703-13. [PMID: 11034899 DOI: 10.1242/jcs.113.21.3703] [Citation(s) in RCA: 62] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We report a role for HA95, a nuclear protein with high homology to the nuclear A-kinase anchoring protein AKAP95, in the regulation of nuclear envelope-chromatin interactions. Biochemical and photobleaching data indicate that HA95 is tightly associated with chromatin and the nuclear matrix/lamina network in interphase, and bound to chromatin at mitosis. HA95 resides in a complex together with lamin B receptor (LBR), lamina-associated polypeptide (LAP)2 and emerin, integral proteins of the inner nuclear membrane. Cross-linking experiments, however, illustrate a tight association of HA95 with LBR and LAP2 only. Intra-nuclear blocking of HA95 with anti-HA95 antibodies abolishes nuclear breakdown in a mitotic HeLa cell extract. The antibodies inhibit nuclear membrane breakdown and chromatin condensation - the latter independently of nuclear membranes. However, lamina disassembly is not affected, as judged by immunological analyses of A/C- and B-type lamins. In contrast, immunoblocking of HA95 bound to condensed chromosomes does not impair chromatin decondensation, nuclear membrane reassembly or lamina reformation. Our results argue for a role for HA95 in anchoring nuclear membranes and lamins to chromatin in interphase, and in releasing membranes from chromatin at mitosis. The data also suggest that HA95 is not involved in initial binding of membranes to chromatin upon nuclear reassembly. We propose that HA95 is a central platform at the chromatin/nuclear matrix interface implicated in regulating nuclear envelope-chromatin interactions during the cell cycle.
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Affiliation(s)
- S B Martins
- Institute of Medical Biochemistry, University of Oslo, PO Box 1112 Blindern, Norway
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Steen RL, Martins SB, Taskén K, Collas P. Recruitment of protein phosphatase 1 to the nuclear envelope by A-kinase anchoring protein AKAP149 is a prerequisite for nuclear lamina assembly. J Cell Biol 2000; 150:1251-62. [PMID: 10995432 PMCID: PMC2150688 DOI: 10.1083/jcb.150.6.1251] [Citation(s) in RCA: 124] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Subcellular targeting of cAMP-dependent protein kinase (protein kinase A [PKA]) and of type 1 protein phosphatase (PP1) is believed to enhance the specificity of these enzymes. We report that in addition to anchoring PKA, A-kinase anchoring protein AKAP149 recruits PP1 at the nuclear envelope (NE) upon somatic nuclear reformation in vitro, and that PP1 targeting to the NE is a prerequisite for assembly of B-type lamins. AKAP149 is an integral membrane protein of the endoplasmic reticulum/NE network. The PP1-binding domain of AKAP149 was identified as K(153)GVLF(157). PP1 binds immobilized AKAP149 in vitro and coprecipitates with AKAP149 from purified NE extracts. Affinity isolation of PP1 from solubilized NEs copurifies AKAP149. Upon reassembly of somatic nuclei in interphase extract, PP1 is targeted to the NE. Targeting is inhibited by a peptide containing the PP1-binding domain of AKAP149, abolished in nuclei assembled with membranes immunodepleted of AKAP149, and restored after reincorporation of AKAP149 into nuclear membranes. B-type lamins do not assemble into a lamina when NE targeting of PP1 is abolished, and is rescued upon recruitment of PP1 to the NE. We propose that kinase and phosphatase anchoring at the NE by AKAP149 plays in a role in modulating nuclear reassembly at the end of mitosis.
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Affiliation(s)
- R L Steen
- Institute of Medical Biochemistry, University of Oslo, 0317 Oslo, Norway
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Terjung B, Spengler U, Sauerbruch T, Worman HJ. "Atypical p-ANCA" in IBD and hepatobiliary disorders react with a 50-kilodalton nuclear envelope protein of neutrophils and myeloid cell lines. Gastroenterology 2000; 119:310-22. [PMID: 10930366 DOI: 10.1053/gast.2000.9366] [Citation(s) in RCA: 101] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
BACKGROUND & AIMS Atypical "antineutrophil cytoplasmic antibodies" (ANCA) are present in patients with ulcerative colitis (UC), primary sclerosing cholangitis (PSC), and autoimmune hepatitis (AIH). Recently, we showed that atypical p-ANCA react with nuclear envelope proteins of neutrophils. Based on this observation, we aimed to characterize the nuclear antigen recognized by atypical p-ANCA. METHODS We prepared cytoplasmic and nuclear extracts of human neutrophils, human HL-60, and murine 32D myeloid cells. Proteins were resolved by 1- and 2-dimensional gel electrophoresis. Reactive proteins were detected by immunoblotting with sera from 118 individuals (UC, 25; PSC, 28; AIH, 35; disease and normal controls, 30). Atypical p-ANCA (n = 64) were affinity-purified against the reactive protein and investigated for their immunofluorescence pattern using confocal microscopy. RESULTS Immunoblotting showed reactivity to a myeloid-specific 50-kilodalton nuclear protein with an isoelectric point of pH 6.0 detected in 92% (59 of 64) of the patients with inflammatory bowel or hepatobiliary diseases and atypical p-ANCA. Affinity-purified antibodies against the 50-kilodalton protein gave a nuclear rim-like fluorescence on myeloid cells examined by immunofluorescence microscopy. Affinity-purified antibodies did not recognize antigens in nonmyeloid cells. CONCLUSIONS Atypical p-ANCA in UC, PSC, or AIH recognize a 50-kilodalton myeloid-specific nuclear envelope protein.
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Affiliation(s)
- B Terjung
- Division of Digestive and Liver Diseases, Departments of Medicine and Anatomy and Cell Biology, College of Physicians and Surgeons, Columbia University, New York, New York 10032, USA
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Reinton N, Orstavik S, Haugen TB, Jahnsen T, Taskén K, Skålhegg BS. A novel isoform of human cyclic 3',5'-adenosine monophosphate-dependent protein kinase, c alpha-s, localizes to sperm midpiece. Biol Reprod 2000; 63:607-11. [PMID: 10906071 DOI: 10.1095/biolreprod63.2.607] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Abstract
Using rapid amplification of cDNA ends, a cDNA encoding a novel splice variant of the human C alpha catalytic subunit of cAMP-dependent protein kinase (PKA) was identified. The novel isoform differed only in the N-terminal part of the deduced amino acid sequence, corresponding to the part encoded by exon 1 in the previously characterized murine C alpha gene. Sequence comparison revealed similarity to an ovine C alpha variant characterized by protein purification and micropeptide sequencing, C alpha-s, identifying the cloned human cDNA as the C alpha-s isoform. The C alpha-s mRNA was expressed exclusively in human testis and expression in isolated human pachytene spermatocytes was demonstrated. The C alpha-s protein was present in ejaculated human sperm, and immunofluorescent labeling with a C alpha-s-specific antibody indicated that C alpha-s was localized in the midpiece region of the spermatozoon. The majority of C alpha-s was particulate and could not be released from the sperm midpiece by cAMP treatment alone. Furthermore, detergent extraction solubilized approximately two-thirds of the C alpha-s pool, indicating interaction both with detergent-resistant cytoskeletal and membrane structures. In addition, we recently identified the regulatory subunit isoforms RI alpha, RII alpha, and an A-kinase anchoring protein, hAKAP220 in this region in sperm that could target C alpha-s. This novel C alpha-s splice variant appeared to have an independent anchor in the human sperm midpiece as it could not be completely solubilized even in the presence of both detergent and cAMP.
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Affiliation(s)
- N Reinton
- Institute of Medical Biochemistry, University of Oslo, N-0317 Oslo, Norway
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48
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Reinton N, Collas P, Haugen TB, Skâlhegg BS, Hansson V, Jahnsen T, Taskén K. Localization of a novel human A-kinase-anchoring protein, hAKAP220, during spermatogenesis. Dev Biol 2000; 223:194-204. [PMID: 10864471 DOI: 10.1006/dbio.2000.9725] [Citation(s) in RCA: 90] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Using a combination of protein kinase A type II overlay screening, rapid amplification of cDNA ends, and database searches, a contig of 9923 bp was assembled and characterized in which the open reading frame encoded a 1901-amino-acid A-kinase-anchoring protein (AKAP) with an apparent SDS-PAGE mobility of 220 kDa, named human AKAP220 (hAKAP220). The hAKAP220 amino acid sequence revealed high similarity to rat AKAP220 in the 1167 C-terminal residues, but contained 727 residues in the N-terminus not present in the reported rat AKAP220 sequence. The hAKAP220 mRNA was expressed at high levels in human testis and in isolated human pachytene spermatocytes and round spermatids. The hAKAP220 protein was present in human male germ cells and mature sperm. Immunofluorescent labeling with specific antibodies indicated that hAKAP220 was localized in the cytoplasm of premeiotic pachytene spermatocytes and in the centrosome of developing postmeiotic germ cells, while a midpiece/centrosome localization was found in elongating spermatocytes and mature sperm. The hAKAP220 protein together with a fraction of PKA types I and II and protein phosphatase I was resistant to detergent extraction of sperm tails, suggesting an association with cytoskeletal structures. In contrast, S-AKAP84/D-AKAP1, which is also present in the midpiece, was extracted under the same conditions. Anti-hAKAP220 antisera coimmunoprecipitated both type I and type II regulatory subunits of PKA in human testis lysates, indicating that hAKAP220 interacts with both classes of R subunits, either through separate or through a common binding motif(s).
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Affiliation(s)
- N Reinton
- Institute of Medical Biochemistry, University of Oslo, Oslo, N-0317, Norway
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49
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Affiliation(s)
- P Collas
- Institute of Medical Biochemistry, University of Oslo, Norway
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50
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Abstract
At fertilization, the dormant sperm nucleus undergoes morphological and biochemical transformations leading to the development of a functional male pronucleus. We have investigated the formation of the male pronucleus in a cell-free system consisting of permeabilized sea urchin sperm nuclei incubated in fertilized sea urchin egg extract containing membrane vesicles. The first sperm nuclear transformation observed in vitro is the disassembly of the sperm nuclear lamina as a result of lamin B phosphorylation mediated by egg protein kinase C. The conical sperm nucleus then decondenses into a spherical pronucleus in an ATP-dependent manner. The new nuclear envelope (NE) forms by ATP-dependent binding of vesicles to chromatin and GTP-dependent fusion of vesicles with one another. Three cytoplasmic vesicle fractions with distinct properties are required for the formation of the male pronuclear envelope. Binding of each fraction to chromatin requires two detergent-resistant lipophilic structures at each pole of the sperm nucleus, which are incorporated into the NE by membrane fusion. Targeting of the bulk of NE vesicles to chromatin is mediated by a lamin B receptor (LBR)-like integral membrane protein. The last step of male pronuclear formation involves nuclear swelling. Nuclear swelling is associated with import of soluble lamin B into the nucleus and growth of the NE. In the nucleus, lamin B associates with LBR, which apparently tethers the NE to the lamina. Thus, formation of the male pronuclear envelope involves a highly ordered series of reactions.
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Affiliation(s)
- P Collas
- Institute of Medical Biochemistry, Faculty of Medicine, University of Oslo, Norway.
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