51
|
Transfected plasmid DNA is incorporated into the nucleus via nuclear envelope reformation at telophase. Commun Biol 2022; 5:78. [PMID: 35058555 PMCID: PMC8776997 DOI: 10.1038/s42003-022-03021-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2021] [Accepted: 12/27/2021] [Indexed: 12/15/2022] Open
Abstract
AbstractDNA transfection is an important technology in life sciences, wherein nuclear entry of DNA is necessary to express exogenous DNA. Non-viral vectors and their transfection reagents are useful as safe transfection tools. However, they have no effect on the transfection of non-proliferating cells, the reason for which is not well understood. This study elucidates the mechanism through which transfected DNA enters the nucleus for gene expression. To monitor the behavior of transfected DNA, we introduce plasmid bearing lacO repeats and RFP-coding sequences into cells expressing GFP-LacI and observe plasmid behavior and RFP expression in living cells. RFP expression appears only after mitosis. Electron microscopy reveals that plasmids are wrapped with nuclear envelope (NE)‒like membranes or associated with chromosomes at telophase. The depletion of BAF, which is involved in NE reformation, delays plasmid RFP expression. These results suggest that transfected DNA is incorporated into the nucleus during NE reformation at telophase.
Collapse
|
52
|
Janssen AFJ, Breusegem SY, Larrieu D. Current Methods and Pipelines for Image-Based Quantitation of Nuclear Shape and Nuclear Envelope Abnormalities. Cells 2022; 11:347. [PMID: 35159153 PMCID: PMC8834579 DOI: 10.3390/cells11030347] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2021] [Revised: 01/17/2022] [Accepted: 01/18/2022] [Indexed: 02/02/2023] Open
Abstract
Any given cell type has an associated "normal" nuclear morphology, which is important to maintain proper cellular functioning and safeguard genomic integrity. Deviations from this can be indicative of diseases such as cancer or premature aging syndrome. To accurately assess nuclear abnormalities, it is important to use quantitative measures of nuclear morphology. Here, we give an overview of several nuclear abnormalities, including micronuclei, nuclear envelope invaginations, blebs and ruptures, and review the current methods used for image-based quantification of these abnormalities. We discuss several parameters that can be used to quantify nuclear shape and compare their outputs using example images. In addition, we present new pipelines for quantitative analysis of nuclear blebs and invaginations. Quantitative analyses of nuclear aberrations and shape will be important in a wide range of applications, from assessments of cancer cell anomalies to studies of nucleus deformability under mechanical or other types of stress.
Collapse
Affiliation(s)
| | | | - Delphine Larrieu
- Department of Clinical Biochemistry, Addenbrookes Biomedical Campus, Cambridge Institute for Medical Research, University of Cambridge, Cambridge CB2 0XY, UK; (A.F.J.J.); (S.Y.B.)
| |
Collapse
|
53
|
Shankar R, Lettman MM, Whisler W, Frankel EB, Audhya A. The ESCRT machinery directs quality control over inner nuclear membrane architecture. Cell Rep 2022; 38:110263. [PMID: 35045304 PMCID: PMC8801257 DOI: 10.1016/j.celrep.2021.110263] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2021] [Revised: 11/21/2021] [Accepted: 12/21/2021] [Indexed: 11/20/2022] Open
Abstract
The late-acting endosomal sorting complex required for transport (ESCRT) machinery has been implicated in facilitating the resealing of the nuclear envelope (NE) after mitosis, enabling compartmentalization of the genome away from the cytoplasm. Here, we leverage the stereotypic first division of the C. elegans embryo to identify additional functions of the ESCRT machinery in maintaining the structure of the inner nuclear membrane. Specifically, impaired ESCRT function results in a defect in the pruning of inner nuclear membrane invaginations, which arise normally during NE reformation and expansion. Additionally, in combination with a hypomorphic mutation that interferes with assembly of the underlying nuclear lamina, inhibition of ESCRT function significantly perturbs NE architecture and increases chromosome segregation defects, resulting in penetrant embryonic lethality. Our findings highlight links between ESCRT-mediated inner nuclear membrane remodeling, maintenance of nuclear envelope morphology, and the preservation of the genome during early development. In this study, Shankar et al. demonstrate that defects in ESCRT machinery functions impair pruning of inner nuclear membrane invaginations that form normally after mitotic exit as the nuclear envelope undergoes expansion. These findings highlight a critical role for the ESCRT machinery in the maintenance of inner nuclear membrane morphology.
Collapse
Affiliation(s)
- Raakhee Shankar
- Department of Biomolecular Chemistry, University of Wisconsin School of Medicine and Public Health, Madison, WI 53705, USA
| | - Molly M Lettman
- Department of Biomolecular Chemistry, University of Wisconsin School of Medicine and Public Health, Madison, WI 53705, USA
| | - William Whisler
- Department of Biomolecular Chemistry, University of Wisconsin School of Medicine and Public Health, Madison, WI 53705, USA
| | - Elisa B Frankel
- Department of Biomolecular Chemistry, University of Wisconsin School of Medicine and Public Health, Madison, WI 53705, USA
| | - Anjon Audhya
- Department of Biomolecular Chemistry, University of Wisconsin School of Medicine and Public Health, Madison, WI 53705, USA.
| |
Collapse
|
54
|
Coupling lipid synthesis with nuclear envelope remodeling. Trends Biochem Sci 2022; 47:52-65. [PMID: 34556392 PMCID: PMC9943564 DOI: 10.1016/j.tibs.2021.08.009] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2021] [Revised: 08/12/2021] [Accepted: 08/25/2021] [Indexed: 01/10/2023]
Abstract
The nuclear envelope (NE) is a protective barrier to the genome, yet its membranes undergo highly dynamic remodeling processes that are necessary for cell growth and maintenance. While mechanisms by which proteins promote NE remodeling are emerging, the types of bilayer lipids and the lipid-protein interactions that define and sculpt nuclear membranes remain elusive. The NE is continuous with the endoplasmic reticulum (ER) and recent evidence suggests that lipids produced in the ER are harnessed to remodel nuclear membranes. In this review, we examine new roles for lipid species made proximally within the ER and locally at the NE to control NE dynamics. We further explore how the biosynthesis of lipids coordinates NE remodeling to ensure genome protection.
Collapse
|
55
|
Rose M, Burgess JT, O’Byrne K, Richard DJ, Bolderson E. The role of inner nuclear membrane proteins in tumourigenesis and as potential targets for cancer therapy. Cancer Metastasis Rev 2022; 41:953-963. [PMID: 36205821 PMCID: PMC9758098 DOI: 10.1007/s10555-022-10065-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/22/2022] [Accepted: 09/18/2022] [Indexed: 01/25/2023]
Abstract
Despite significant advances in our understanding of tumourigenesis and cancer therapeutics, cancer continues to account for 30% of worldwide deaths. Therefore, there remains an unmet need for the development of cancer therapies to improve patient quality of life and survival outcomes. The inner nuclear membrane has an essential role in cell division, cell signalling, transcription, cell cycle progression, chromosome tethering, cell migration and mitosis. Furthermore, expression of several inner nuclear membrane proteins has been shown to be frequently altered in tumour cells, resulting in the dysregulation of cellular pathways to promote tumourigenesis. However, to date, minimal research has been conducted to investigate how targeting these dysregulated and variably expressed proteins may provide a novel avenue for cancer therapies. In this review, we present an overview of the involvement of the inner nuclear membrane proteins within the hallmarks of cancer and how they may be exploited as potent anti-cancer therapeutics.
Collapse
Affiliation(s)
- Maddison Rose
- grid.1024.70000000089150953Cancer & Ageing Research Program (CARP), Centre for Genomics and Personalised Health (CGPH), School of Biomedical Sciences, Queensland University of Technology (QUT), Brisbane, QLD Australia
| | - Joshua T. Burgess
- grid.1024.70000000089150953Cancer & Ageing Research Program (CARP), Centre for Genomics and Personalised Health (CGPH), School of Biomedical Sciences, Queensland University of Technology (QUT), Brisbane, QLD Australia
| | - Kenneth O’Byrne
- grid.1024.70000000089150953Cancer & Ageing Research Program (CARP), Centre for Genomics and Personalised Health (CGPH), School of Biomedical Sciences, Queensland University of Technology (QUT), Brisbane, QLD Australia ,grid.412744.00000 0004 0380 2017Princess Alexandra Hospital, Ipswich Road, Woolloongabba, Brisbane, QLD 4102 Australia
| | - Derek J. Richard
- grid.1024.70000000089150953Cancer & Ageing Research Program (CARP), Centre for Genomics and Personalised Health (CGPH), School of Biomedical Sciences, Queensland University of Technology (QUT), Brisbane, QLD Australia
| | - Emma Bolderson
- grid.1024.70000000089150953Cancer & Ageing Research Program (CARP), Centre for Genomics and Personalised Health (CGPH), School of Biomedical Sciences, Queensland University of Technology (QUT), Brisbane, QLD Australia
| |
Collapse
|
56
|
Wallis SS, Ventimiglia LN, Otigbah E, Infante E, Cuesta-Geijo MA, Kidiyoor GR, Carbajal MA, Fleck RA, Foiani M, Garcia-Manyes S, Martin-Serrano J, Agromayor M. The ESCRT machinery counteracts Nesprin-2G-mediated mechanical forces during nuclear envelope repair. Dev Cell 2021; 56:3192-3202.e8. [PMID: 34818527 PMCID: PMC8657813 DOI: 10.1016/j.devcel.2021.10.022] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2020] [Revised: 08/03/2021] [Accepted: 10/28/2021] [Indexed: 12/31/2022]
Abstract
Transient nuclear envelope ruptures during interphase (NERDI) occur due to cytoskeletal compressive forces at sites of weakened lamina, and delayed NERDI repair results in genomic instability. Nuclear envelope (NE) sealing is completed by endosomal sorting complex required for transport (ESCRT) machinery. A key unanswered question is how local compressive forces are counteracted to allow efficient membrane resealing. Here, we identify the ESCRT-associated protein BROX as a crucial factor required to accelerate repair of the NE. Critically, BROX binds Nesprin-2G, a component of the linker of nucleoskeleton and cytoskeleton complex (LINC). This interaction promotes Nesprin-2G ubiquitination and facilitates the relaxation of mechanical stress imposed by compressive actin fibers at the rupture site. Thus, BROX rebalances excessive cytoskeletal forces in cells experiencing NE instability to promote effective NERDI repair. Our results demonstrate that BROX coordinates mechanoregulation with membrane remodeling to ensure the maintenance of nuclear-cytoplasmic compartmentalization and genomic stability. Cytoskeletal forces exerted on the nucleus can rupture its membrane BROX is recruited to sites of rupture by the ESCRT membrane remodeling machinery BROX ubiquitinates the LINC complex protein Nesprin-2G, targeting it for degradation BROX coordinates local relaxation of mechanical stress with membrane remodeling
Collapse
Affiliation(s)
- Samuel S Wallis
- Department of Infectious Diseases, King's College London, Faculty of Life Sciences & Medicine, London SE1 9RT, UK
| | - Leandro N Ventimiglia
- Department of Infectious Diseases, King's College London, Faculty of Life Sciences & Medicine, London SE1 9RT, UK
| | - Evita Otigbah
- Department of Infectious Diseases, King's College London, Faculty of Life Sciences & Medicine, London SE1 9RT, UK
| | - Elvira Infante
- Department of Physics, Randall Centre for Cell and Molecular Biophysics, and London Centre for Nanotechnology, King's College London, London WC2R 2LS, UK
| | - Miguel Angel Cuesta-Geijo
- Department of Infectious Diseases, King's College London, Faculty of Life Sciences & Medicine, London SE1 9RT, UK; Centro Nacional Instituto de Investigación y Tecnología Agraria y Alimentaria (CSIC), Ctra. de la Coruña Km 7.5, 28040 Madrid, Spain
| | - Gururaj Rao Kidiyoor
- Fondazione Istituto FIRC di Oncologia Molecolare (IFOM), Via Adamello 16, 20139 Milan, Italy; Università degli Studi di Milano, 20122 Milan, Italy
| | | | - Roland A Fleck
- Centre for Ultrastructural Imaging, King's College London, London SE1 1UL, UK
| | - Marco Foiani
- Fondazione Istituto FIRC di Oncologia Molecolare (IFOM), Via Adamello 16, 20139 Milan, Italy; Università degli Studi di Milano, 20122 Milan, Italy
| | - Sergi Garcia-Manyes
- Department of Physics, Randall Centre for Cell and Molecular Biophysics, and London Centre for Nanotechnology, King's College London, London WC2R 2LS, UK; the Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK
| | - Juan Martin-Serrano
- Department of Infectious Diseases, King's College London, Faculty of Life Sciences & Medicine, London SE1 9RT, UK.
| | - Monica Agromayor
- Department of Infectious Diseases, King's College London, Faculty of Life Sciences & Medicine, London SE1 9RT, UK.
| |
Collapse
|
57
|
Rose M, Bai B, Tang M, Cheong CM, Beard S, Burgess JT, Adams MN, O'Byrne KJ, Richard DJ, Gandhi NS, Bolderson E. The Impact of Rare Human Variants on Barrier-To-Auto-Integration Factor 1 (Banf1) Structure and Function. Front Cell Dev Biol 2021; 9:775441. [PMID: 34820387 PMCID: PMC8606531 DOI: 10.3389/fcell.2021.775441] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2021] [Accepted: 10/18/2021] [Indexed: 11/23/2022] Open
Abstract
Barrier-to-Autointegration Factor 1 (Banf1/BAF) is a critical component of the nuclear envelope and is involved in the maintenance of chromatin structure and genome stability. Banf1 is a small DNA binding protein that is conserved amongst multicellular eukaryotes. Banf1 functions as a dimer, and binds non-specifically to the phosphate backbone of DNA, compacting the DNA in a looping process. The loss of Banf1 results in loss of nuclear envelope integrity and aberrant chromatin organisation. Significantly, mutations in Banf1 are associated with the severe premature ageing syndrome, Néstor–Guillermo Progeria Syndrome. Previously, rare human variants of Banf1 have been identified, however the impact of these variants on Banf1 function has not been explored. Here, using in silico modelling, biophysical and cell-based approaches, we investigate the effect of rare human variants on Banf1 structure and function. We show that these variants do not significantly alter the secondary structure of Banf1, but several single amino acid variants in the N- and C-terminus of Banf1 impact upon the DNA binding ability of Banf1, without altering Banf1 localisation or nuclear integrity. The functional characterisation of these variants provides further insight into Banf1 structure and function and may aid future studies examining the potential impact of Banf1 function on nuclear structure and human health.
Collapse
Affiliation(s)
- Maddison Rose
- Queensland University of Technology (QUT), Cancer and Ageing Research Program, Centre for Genomics and Personalised Health, Translational Research Institute (TRI), Brisbane, QLD, Australia
| | - Bond Bai
- Queensland University of Technology (QUT), Cancer and Ageing Research Program, Centre for Genomics and Personalised Health, Translational Research Institute (TRI), Brisbane, QLD, Australia
| | - Ming Tang
- Queensland University of Technology (QUT), Cancer and Ageing Research Program, Centre for Genomics and Personalised Health, Translational Research Institute (TRI), Brisbane, QLD, Australia
| | - Chee Man Cheong
- Queensland University of Technology (QUT), Cancer and Ageing Research Program, Centre for Genomics and Personalised Health, Translational Research Institute (TRI), Brisbane, QLD, Australia
| | - Sam Beard
- Queensland University of Technology (QUT), Cancer and Ageing Research Program, Centre for Genomics and Personalised Health, Translational Research Institute (TRI), Brisbane, QLD, Australia
| | - Joshua T Burgess
- Queensland University of Technology (QUT), Cancer and Ageing Research Program, Centre for Genomics and Personalised Health, Translational Research Institute (TRI), Brisbane, QLD, Australia
| | - Mark N Adams
- Queensland University of Technology (QUT), Cancer and Ageing Research Program, Centre for Genomics and Personalised Health, Translational Research Institute (TRI), Brisbane, QLD, Australia
| | - Kenneth J O'Byrne
- Queensland University of Technology (QUT), Cancer and Ageing Research Program, Centre for Genomics and Personalised Health, Translational Research Institute (TRI), Brisbane, QLD, Australia.,Princess Alexandra Hospital, Woolloongabba, QLD, Australia
| | - Derek J Richard
- Queensland University of Technology (QUT), Cancer and Ageing Research Program, Centre for Genomics and Personalised Health, Translational Research Institute (TRI), Brisbane, QLD, Australia
| | - Neha S Gandhi
- Queensland University of Technology (QUT), Cancer and Ageing Research Program, Centre for Genomics and Personalised Health, Translational Research Institute (TRI), Brisbane, QLD, Australia.,School of Chemistry and Physics, Queensland University of Technology, Brisbane, QLD, Australia
| | - Emma Bolderson
- Queensland University of Technology (QUT), Cancer and Ageing Research Program, Centre for Genomics and Personalised Health, Translational Research Institute (TRI), Brisbane, QLD, Australia
| |
Collapse
|
58
|
Amar K, Wei F, Chen J, Wang N. Effects of forces on chromatin. APL Bioeng 2021; 5:041503. [PMID: 34661040 PMCID: PMC8516479 DOI: 10.1063/5.0065302] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2021] [Accepted: 09/27/2021] [Indexed: 12/29/2022] Open
Abstract
Chromatin is a unique structure of DNA and histone proteins in the cell nucleus and the site of dynamic regulation of gene expression. Soluble factors are known to affect the chromatin structure and function via activating or inhibiting specific transcription factors. Forces on chromatin come from exogenous stresses on the cell surface and/or endogenous stresses, which are regulated by substrate mechanics, geometry, and topology. Forces on chromatin involve direct (via adhesion molecules, cytoskeleton, and the linker of nucleoskeleton and cytoskeleton complexes) and indirect (via diffusion and/or translocation processes) signaling pathways to modulate levels of chromatin folding and deformation to regulate transcription, which is controlled by histone modifications and depends on magnitude, direction, rate/frequency, duration, and modes of stresses. The rapid force transmission pathway activates multiple genes simultaneously, and the force may act like a "supertranscription factor." The indirect mechanotransduction pathways and the rapid force transmission pathway together exert sustained impacts on the chromatin, the nucleus, and cell functions.
Collapse
Affiliation(s)
- Kshitij Amar
- Department of Mechanical Science and Engineering, The Grainger College of Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA
| | - Fuxiang Wei
- Key Laboratory of Molecular Biophysics of the Ministry of Education, Department of Biomedical Engineering, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China
| | - Junwei Chen
- Key Laboratory of Molecular Biophysics of the Ministry of Education, Department of Biomedical Engineering, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China
| | - Ning Wang
- Department of Mechanical Science and Engineering, The Grainger College of Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA
| |
Collapse
|
59
|
Isono E. ESCRT Is a Great Sealer: Non-Endosomal Function of the ESCRT Machinery in Membrane Repair and Autophagy. PLANT & CELL PHYSIOLOGY 2021; 62:766-774. [PMID: 33768242 DOI: 10.1093/pcp/pcab045] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/31/2020] [Revised: 02/18/2021] [Accepted: 03/23/2021] [Indexed: 06/12/2023]
Abstract
Components of the endosomal sorting complex required for transport (ESCRTs) were first identified in a genetic screen in budding yeast as factors interfering with vacuolar protein sorting. In the last three decades, intensive studies have revealed the subunit composition of ESCRT-0, ESCRT-I, ESCRT-II, ESCRT-III, their structure, the assembling mechanisms and their molecular and physiological functions. In plants, ESCRTs are essential for development, growth and stress responses. ESCRTs are best known for their function in endosomal trafficking, during which they are required for sorting ubiquitylated membrane proteins into intraluminal vesicles (ILVs) of multivesicular endosomes (MVEs). The formation of ILVs requires the function of ESCRT-III, which has been shown to mediate the membrane scission. Although the function of plant ESCRTs has been predominantly discussed in the context of endosomal trafficking, recent studies in other model organisms revealed a versatile role of ESCRTs in diverse cellular events with broad physiological implications. The non-endosomal functions of ESCRTs include cytokinesis, viral budding, autophagy, nuclear envelope reformation and membrane repair, although many of these have not yet been studied in plants. In this review, recent findings on non-endosomal ESCRT functions in plant, yeast and animals are highlighted and discussed.
Collapse
Affiliation(s)
- Erika Isono
- Department of Biology, University of Konstanz, Universitätsstrasse 10, Konstanz 78464, Germany
| |
Collapse
|
60
|
Napoletano F, Ferrari Bravo G, Voto IAP, Santin A, Celora L, Campaner E, Dezi C, Bertossi A, Valentino E, Santorsola M, Rustighi A, Fajner V, Maspero E, Ansaloni F, Cancila V, Valenti CF, Santo M, Artimagnella OB, Finaurini S, Gioia U, Polo S, Sanges R, Tripodo C, Mallamaci A, Gustincich S, d'Adda di Fagagna F, Mantovani F, Specchia V, Del Sal G. The prolyl-isomerase PIN1 is essential for nuclear Lamin-B structure and function and protects heterochromatin under mechanical stress. Cell Rep 2021; 36:109694. [PMID: 34525372 DOI: 10.1016/j.celrep.2021.109694] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2021] [Revised: 06/29/2021] [Accepted: 08/19/2021] [Indexed: 01/24/2023] Open
Abstract
Chromatin organization plays a crucial role in tissue homeostasis. Heterochromatin relaxation and consequent unscheduled mobilization of transposable elements (TEs) are emerging as key contributors of aging and aging-related pathologies, including Alzheimer's disease (AD) and cancer. However, the mechanisms governing heterochromatin maintenance or its relaxation in pathological conditions remain poorly understood. Here we show that PIN1, the only phosphorylation-specific cis/trans prolyl isomerase, whose loss is associated with premature aging and AD, is essential to preserve heterochromatin. We demonstrate that this PIN1 function is conserved from Drosophila to humans and prevents TE mobilization-dependent neurodegeneration and cognitive defects. Mechanistically, PIN1 maintains nuclear type-B Lamin structure and anchoring function for heterochromatin protein 1α (HP1α). This mechanism prevents nuclear envelope alterations and heterochromatin relaxation under mechanical stress, which is a key contributor to aging-related pathologies.
Collapse
Affiliation(s)
- Francesco Napoletano
- Laboratorio Nazionale CIB (LNCIB), Area Science Park, Padriciano 99, 34149 Trieste, Italy; Department of Life Sciences (DSV), University of Trieste, 34127 Trieste, Italy.
| | - Gloria Ferrari Bravo
- Laboratorio Nazionale CIB (LNCIB), Area Science Park, Padriciano 99, 34149 Trieste, Italy; Department of Life Sciences (DSV), University of Trieste, 34127 Trieste, Italy
| | - Ilaria Anna Pia Voto
- Laboratorio Nazionale CIB (LNCIB), Area Science Park, Padriciano 99, 34149 Trieste, Italy
| | - Aurora Santin
- Laboratorio Nazionale CIB (LNCIB), Area Science Park, Padriciano 99, 34149 Trieste, Italy
| | - Lucia Celora
- Laboratorio Nazionale CIB (LNCIB), Area Science Park, Padriciano 99, 34149 Trieste, Italy
| | - Elena Campaner
- Laboratorio Nazionale CIB (LNCIB), Area Science Park, Padriciano 99, 34149 Trieste, Italy; Department of Life Sciences (DSV), University of Trieste, 34127 Trieste, Italy
| | - Clara Dezi
- Department of Life Sciences (DSV), University of Trieste, 34127 Trieste, Italy
| | - Arianna Bertossi
- Laboratorio Nazionale CIB (LNCIB), Area Science Park, Padriciano 99, 34149 Trieste, Italy; Department of Life Sciences (DSV), University of Trieste, 34127 Trieste, Italy
| | - Elena Valentino
- Laboratorio Nazionale CIB (LNCIB), Area Science Park, Padriciano 99, 34149 Trieste, Italy
| | - Mariangela Santorsola
- Laboratorio Nazionale CIB (LNCIB), Area Science Park, Padriciano 99, 34149 Trieste, Italy; Department of Life Sciences (DSV), University of Trieste, 34127 Trieste, Italy
| | - Alessandra Rustighi
- Laboratorio Nazionale CIB (LNCIB), Area Science Park, Padriciano 99, 34149 Trieste, Italy; Department of Life Sciences (DSV), University of Trieste, 34127 Trieste, Italy
| | | | - Elena Maspero
- FIRC Institute of Molecular Oncology (IFOM), 20139 Milan, Italy
| | - Federico Ansaloni
- Area of Neuroscience, International School for Advanced Studies (SISSA), 34146 Trieste, Italy
| | - Valeria Cancila
- Tumor Immunology Unit, Department of Health Science, Human Pathology Section, School of Medicine, University of Palermo, 90133 Palermo, Italy
| | - Cesare Fabio Valenti
- Tumor Immunology Unit, Department of Health Science, Human Pathology Section, School of Medicine, University of Palermo, 90133 Palermo, Italy
| | - Manuela Santo
- Area of Neuroscience, International School for Advanced Studies (SISSA), 34146 Trieste, Italy
| | | | - Sara Finaurini
- Area of Neuroscience, International School for Advanced Studies (SISSA), 34146 Trieste, Italy
| | - Ubaldo Gioia
- FIRC Institute of Molecular Oncology (IFOM), 20139 Milan, Italy
| | - Simona Polo
- FIRC Institute of Molecular Oncology (IFOM), 20139 Milan, Italy
| | - Remo Sanges
- Area of Neuroscience, International School for Advanced Studies (SISSA), 34146 Trieste, Italy
| | - Claudio Tripodo
- FIRC Institute of Molecular Oncology (IFOM), 20139 Milan, Italy; Tumor Immunology Unit, Department of Health Science, Human Pathology Section, School of Medicine, University of Palermo, 90133 Palermo, Italy
| | - Antonello Mallamaci
- Area of Neuroscience, International School for Advanced Studies (SISSA), 34146 Trieste, Italy
| | - Stefano Gustincich
- Area of Neuroscience, International School for Advanced Studies (SISSA), 34146 Trieste, Italy; Central RNA Laboratory, Italian Institute of Technology, 16163 Genova, Italy
| | - Fabrizio d'Adda di Fagagna
- FIRC Institute of Molecular Oncology (IFOM), 20139 Milan, Italy; Institute of Molecular Genetics, National Research Institute (CNR), Pavia, Italy
| | - Fiamma Mantovani
- Laboratorio Nazionale CIB (LNCIB), Area Science Park, Padriciano 99, 34149 Trieste, Italy; Department of Life Sciences (DSV), University of Trieste, 34127 Trieste, Italy
| | - Valeria Specchia
- Department of Biological and Environmental Sciences and Technologies (DiSTeBA), University of Salento, 73100 Lecce, Italy
| | - Giannino Del Sal
- Laboratorio Nazionale CIB (LNCIB), Area Science Park, Padriciano 99, 34149 Trieste, Italy; Department of Life Sciences (DSV), University of Trieste, 34127 Trieste, Italy; FIRC Institute of Molecular Oncology (IFOM), 20139 Milan, Italy.
| |
Collapse
|
61
|
Pawar S, Kutay U. The Diverse Cellular Functions of Inner Nuclear Membrane Proteins. Cold Spring Harb Perspect Biol 2021; 13:a040477. [PMID: 33753404 PMCID: PMC8411953 DOI: 10.1101/cshperspect.a040477] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The nuclear compartment is delimited by a specialized expanded sheet of the endoplasmic reticulum (ER) known as the nuclear envelope (NE). Compared to the outer nuclear membrane and the contiguous peripheral ER, the inner nuclear membrane (INM) houses a unique set of transmembrane proteins that serve a staggering range of functions. Many of these functions reflect the exceptional position of INM proteins at the membrane-chromatin interface. Recent research revealed that numerous INM proteins perform crucial roles in chromatin organization, regulation of gene expression, genome stability, and mediation of signaling pathways into the nucleus. Other INM proteins establish mechanical links between chromatin and the cytoskeleton, help NE remodeling, or contribute to the surveillance of NE integrity and homeostasis. As INM proteins continue to gain prominence, we review these advancements and give an overview on the functional versatility of the INM proteome.
Collapse
Affiliation(s)
- Sumit Pawar
- Institute of Biochemistry, Department of Biology, ETH Zurich, 8093 Zurich, Switzerland
| | - Ulrike Kutay
- Institute of Biochemistry, Department of Biology, ETH Zurich, 8093 Zurich, Switzerland
| |
Collapse
|
62
|
Nakamura K, Ishii Y, Takasu S, Nohmi T, Shibutani M, Ogawa K. Chromosome aberrations induced by the non-mutagenic carcinogen acetamide involve in rat hepatocarcinogenesis through micronucleus formation in hepatocytes. Arch Toxicol 2021; 95:2851-2865. [PMID: 34160648 DOI: 10.1007/s00204-021-03099-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2021] [Accepted: 06/15/2021] [Indexed: 12/12/2022]
Abstract
Chromosome aberrations (CAs), i.e. changes in chromosome number or structure, are known to cause chromosome rearrangements and subsequently tumorigenesis. However, the involvement of CAs in chemical-induced carcinogenesis is unclear. In the current study, we aimed to clarify the possible involvement of CAs in chemical carcinogenesis using a rat model with the non-mutagenic hepatocarcinogen acetamide. In an in vivo micronucleus (MN) test, acetamide was revealed to induce CAs specifically in rat liver at carcinogenic doses. Acetamide also induced centromere-positive large MN (LMN) in hepatocytes. Immunohistochemical and electron microscopic analyses of the LMN, which can be histopathologically detected as basophilic cytoplasmic inclusion, revealed abnormal expression of nuclear envelope proteins, increased heterochromatinization, and massive DNA damage. These molecular pathological features in LMN progressed with acetamide exposure in a time-dependent manner, implying that LMN formation can lead to chromosome rearrangements. Overall, these data suggested that CAs induced by acetamide play a pivotal role in acetamide-induced hepatocarcinogenesis in rats and that CAs can cause chemical carcinogenesis in animals via MN formation.
Collapse
Affiliation(s)
- Kenji Nakamura
- Division of Pathology, National Institute of Health Sciences, 3-25-26 Tonomachi, Kawasaki-ku, Kawasaki-shi, Kanagawa, 210-9501, Japan
- Laboratory of Veterinary Pathology, Tokyo University of Agriculture and Technology, 3-5-8 Saiwai-cho, Fuchu-shi, Tokyo, 183-8509, Japan
| | - Yuji Ishii
- Division of Pathology, National Institute of Health Sciences, 3-25-26 Tonomachi, Kawasaki-ku, Kawasaki-shi, Kanagawa, 210-9501, Japan.
| | - Shinji Takasu
- Division of Pathology, National Institute of Health Sciences, 3-25-26 Tonomachi, Kawasaki-ku, Kawasaki-shi, Kanagawa, 210-9501, Japan
| | - Takehiko Nohmi
- Division of Pathology, National Institute of Health Sciences, 3-25-26 Tonomachi, Kawasaki-ku, Kawasaki-shi, Kanagawa, 210-9501, Japan
| | - Makoto Shibutani
- Laboratory of Veterinary Pathology, Tokyo University of Agriculture and Technology, 3-5-8 Saiwai-cho, Fuchu-shi, Tokyo, 183-8509, Japan
| | - Kumiko Ogawa
- Division of Pathology, National Institute of Health Sciences, 3-25-26 Tonomachi, Kawasaki-ku, Kawasaki-shi, Kanagawa, 210-9501, Japan
| |
Collapse
|
63
|
Purkayastha P, Jaiswal MK, Lele TP. Molecular cancer cell responses to solid compressive stress and interstitial fluid pressure. Cytoskeleton (Hoboken) 2021; 78:312-322. [PMID: 34291887 DOI: 10.1002/cm.21680] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2021] [Revised: 07/14/2021] [Accepted: 07/15/2021] [Indexed: 01/19/2023]
Abstract
Alterations to the mechanical properties of the microenvironment are a hallmark of cancer. Elevated mechanical stresses exist in many solid tumors and elicit responses from cancer cells. Uncontrolled growth in confined environments gives rise to elevated solid compressive stress on cancer cells. Recruitment of leaky blood vessels and an absence of functioning lymphatic vessels causes a rise in the interstitial fluid pressure. Here we review the role of the cancer cell cytoskeleton and the nucleus in mediating both the initial and adaptive cancer cell response to these two types of mechanical stresses. We review how these mechanical stresses alter cancer cell functions such as proliferation, apoptosis, and migration.
Collapse
Affiliation(s)
- Purboja Purkayastha
- Artie McFerrin Department of Chemical Engineering, Texas A&M University, College Station, Texas, USA
| | - Manish K Jaiswal
- Department of Biomedical Engineering, Texas A&M University, College Station, Texas, USA
| | - Tanmay P Lele
- Artie McFerrin Department of Chemical Engineering, Texas A&M University, College Station, Texas, USA.,Department of Biomedical Engineering, Texas A&M University, College Station, Texas, USA.,Department of Translational Medical Sciences, Texas A&M University, Houston, Texas, USA
| |
Collapse
|
64
|
Kutay U, Jühlen R, Antonin W. Mitotic disassembly and reassembly of nuclear pore complexes. Trends Cell Biol 2021; 31:1019-1033. [PMID: 34294532 DOI: 10.1016/j.tcb.2021.06.011] [Citation(s) in RCA: 45] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2021] [Revised: 06/28/2021] [Accepted: 06/28/2021] [Indexed: 12/19/2022]
Abstract
Nuclear pore complexes (NPCs) are huge protein assemblies within the nuclear envelope (NE) that serve as selective gates for macromolecular transport between nucleus and cytoplasm. When higher eukaryotic cells prepare for division, they rapidly disintegrate NPCs during NE breakdown such that nuclear and cytoplasmic components mix to enable the formation of a cytoplasmic mitotic spindle. At the end of mitosis, reassembly of NPCs is coordinated with the establishment of the NE around decondensing chromatin. We review recent progress on mitotic NPC disassembly and reassembly, focusing on vertebrate cells. We highlight novel mechanistic insights into how NPCs are rapidly disintegrated into conveniently reusable building blocks, and put divergent models of (post-)mitotic NPC assembly into a spatial and temporal context.
Collapse
Affiliation(s)
- Ulrike Kutay
- Institute of Biochemistry, Department of Biology, Eidgenössische Technische Hochschule (ETH) Zurich, Otto-Stern-Weg 3, 8093 Zurich, Switzerland.
| | - Ramona Jühlen
- Institute of Biochemistry and Molecular Cell Biology, Medical School, Rheinisch-Westfälische Technische Hochschule (RWTH) Aachen University, Pauwelsstrasse 30, 52074 Aachen, Germany
| | - Wolfram Antonin
- Institute of Biochemistry and Molecular Cell Biology, Medical School, Rheinisch-Westfälische Technische Hochschule (RWTH) Aachen University, Pauwelsstrasse 30, 52074 Aachen, Germany.
| |
Collapse
|
65
|
Kamikawa Y, Saito A, Matsuhisa K, Kaneko M, Asada R, Horikoshi Y, Tashiro S, Imaizumi K. OASIS/CREB3L1 is a factor that responds to nuclear envelope stress. Cell Death Discov 2021; 7:152. [PMID: 34226518 PMCID: PMC8257603 DOI: 10.1038/s41420-021-00540-x] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2021] [Revised: 04/30/2021] [Accepted: 05/29/2021] [Indexed: 11/09/2022] Open
Abstract
The nuclear envelope (NE) safeguards the genome and is pivotal for regulating genome activity as the structural scaffold of higher-order chromatin organization. NE had been thought as the stable during the interphase of cell cycle. However, recent studies have revealed that the NE can be damaged by various stresses such as mechanical stress and cellular senescence. These types of stresses are called NE stress. It has been proposed that NE stress is closely related to cellular dysfunctions such as genome instability and cell death. Here, we found that an endoplasmic reticulum (ER)-resident transmembrane transcription factor, OASIS, accumulates at damaged NE. Notably, the major components of nuclear lamina, Lamin proteins were depleted at the NE where OASIS accumulates. We previously demonstrated that OASIS is cleaved at the membrane domain in response to ER stress. In contrast, OASIS accumulates as the full-length form to damaged NE in response to NE stress. The accumulation to damaged NE is specific for OASIS among OASIS family members. Intriguingly, OASIS colocalizes with the components of linker of nucleoskeleton and cytoskeleton complexes, SUN2 and Nesprin-2 at the damaged NE. OASIS partially colocalizes with BAF, LEM domain proteins, and a component of ESCRT III, which are involved in the repair of ruptured NE. Furthermore, OASIS suppresses DNA damage induced by NE stress and restores nuclear deformation under NE stress conditions. Our findings reveal a novel NE stress response pathway mediated by OASIS.
Collapse
Affiliation(s)
- Yasunao Kamikawa
- Department of Stress Protein Processing, Institute of Biomedical & Health Sciences, Hiroshima University, Hiroshima, Japan.,Department of Biochemistry, Institute of Biomedical & Health Sciences, Hiroshima University, Hiroshima, Japan
| | - Atsushi Saito
- Department of Biochemistry, Institute of Biomedical & Health Sciences, Hiroshima University, Hiroshima, Japan
| | - Koji Matsuhisa
- Department of Biochemistry, Institute of Biomedical & Health Sciences, Hiroshima University, Hiroshima, Japan
| | - Masayuki Kaneko
- Department of Pharmacology and Therapeutic Innovation, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, Japan
| | - Rie Asada
- Division of Endocrinology, Metabolism & Lipid Research, Washington University School of Medicine in St. Louis, St. Louis, MO, USA
| | - Yasunori Horikoshi
- Department of Cellular Biology, Research Institute for Radiation Biology and Medicine, Hiroshima University, Hiroshima, Japan
| | - Satoshi Tashiro
- Department of Cellular Biology, Research Institute for Radiation Biology and Medicine, Hiroshima University, Hiroshima, Japan
| | - Kazunori Imaizumi
- Department of Biochemistry, Institute of Biomedical & Health Sciences, Hiroshima University, Hiroshima, Japan.
| |
Collapse
|
66
|
Wischnewski M, Ablasser A. Interplay of cGAS with chromatin. Trends Biochem Sci 2021; 46:822-831. [PMID: 34215510 DOI: 10.1016/j.tibs.2021.05.011] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2021] [Revised: 05/21/2021] [Accepted: 05/31/2021] [Indexed: 01/07/2023]
Abstract
Recognition of DNA is an evolutionarily highly conserved mechanism of immunity. In mammals, the cGAS-STING pathway plays a central role in coupling DNA sensing to the execution of innate immune mechanisms, both in contexts of infection as well as in noninfectious settings of cellular stress and injury. The indiscriminate ability of double-stranded DNA (dsDNA) to activate cGAS challenges our understanding on how engagement of this pathway is prevented on genomic self-DNA under homeostatic conditions. Here, we review recent discoveries on the regulation of cGAS on chromatin and we discuss implications for cGAS-dependent inflammatory phenotypes. We close by highlighting emerging developments on the role of nuclear cGAS and related open questions for future research.
Collapse
Affiliation(s)
- Marilena Wischnewski
- Global Health Institute, Swiss Federal Institute of Technology Lausanne (EPFL), 1015 Lausanne, Switzerland
| | - Andrea Ablasser
- Global Health Institute, Swiss Federal Institute of Technology Lausanne (EPFL), 1015 Lausanne, Switzerland.
| |
Collapse
|
67
|
Chen NY, Kim PH, Tu Y, Yang Y, Heizer PJ, Young SG, Fong LG. Increased expression of LAP2β eliminates nuclear membrane ruptures in nuclear lamin-deficient neurons and fibroblasts. Proc Natl Acad Sci U S A 2021; 118:e2107770118. [PMID: 34161290 PMCID: PMC8237679 DOI: 10.1073/pnas.2107770118] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Defects or deficiencies in nuclear lamins cause pathology in many cell types, and recent studies have implicated nuclear membrane (NM) ruptures as a cause of cell toxicity. We previously observed NM ruptures and progressive cell death in the developing brain of lamin B1-deficient mouse embryos. We also observed frequent NM ruptures and DNA damage in nuclear lamin-deficient fibroblasts. Factors modulating susceptibility to NM ruptures remain unclear, but we noted low levels of LAP2β, a chromatin-binding inner NM protein, in fibroblasts with NM ruptures. Here, we explored the apparent link between LAP2β and NM ruptures in nuclear lamin-deficient neurons and fibroblasts, and we tested whether manipulating LAP2β expression levels would alter NM rupture frequency. In cortical plate neurons of lamin B1-deficient embryos, we observed a strong correlation between low LAP2β levels and NM ruptures. We also found low LAP2β levels and frequent NM ruptures in neurons of cultured Lmnb1-/- neurospheres. Reducing LAP2β expression in Lmnb1-/- neurons with an siRNA markedly increased the NM rupture frequency (without affecting NM rupture duration), whereas increased LAP2β expression eliminated NM ruptures and reduced DNA damage. Consistent findings were observed in nuclear lamin-deficient fibroblasts. Reduced LAP2β expression increased NM ruptures, whereas increased LAP2β expression virtually abolished NM ruptures. Increased LAP2β expression nearly abolished NM ruptures in cells subjected to mechanical stress (an intervention that increases NM ruptures). Our studies showed that increasing LAP2β expression bolsters NM integrity in nuclear lamin-deficient cells and markedly reduces NM rupture frequency.
Collapse
Affiliation(s)
- Natalie Y Chen
- Department of Medicine, University of California, Los Angeles, CA 90095
| | - Paul H Kim
- Department of Medicine, University of California, Los Angeles, CA 90095
| | - Yiping Tu
- Department of Medicine, University of California, Los Angeles, CA 90095
| | - Ye Yang
- Department of Medicine, University of California, Los Angeles, CA 90095
| | - Patrick J Heizer
- Department of Medicine, University of California, Los Angeles, CA 90095
| | - Stephen G Young
- Department of Medicine, University of California, Los Angeles, CA 90095;
- Department of Human Genetics, University of California, Los Angeles, CA 90095
- Molecular Biology Institute, University of California, Los Angeles, CA 90095
| | - Loren G Fong
- Department of Medicine, University of California, Los Angeles, CA 90095;
| |
Collapse
|
68
|
Le Maout E, Lo Vecchio S, Kumar Korla P, Jinn-Chyuan Sheu J, Riveline D. Ratchetaxis in Channels: Entry Point and Local Asymmetry Set Cell Directions in Confinement. Biophys J 2021; 119:1301-1308. [PMID: 33027610 DOI: 10.1016/j.bpj.2020.08.028] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2020] [Revised: 08/20/2020] [Accepted: 08/26/2020] [Indexed: 01/02/2023] Open
Abstract
Cell motility is essential in a variety of biological phenomena ranging from early development to organ homeostasis and diseases. This phenomenon has mainly been studied and characterized on flat surfaces in vitro, whereas such conditions are rarely observed in vivo. Recently, cell motion in three-dimensional microfabricated channels was reported to be possible, and it was shown that confined cells push on walls. However, rules setting cell directions in this context have not yet been characterized. Here, we show by using assays that ratchetaxis operates in three-dimensional ratchets in fibroblasts and epithelial cancerous cells. Open ratchets rectify cell motion, whereas closed ratchets impose direct cell migration along channels set by the cell orientation at the channel entry point. We also show that nuclei are pressed in constriction zones through mechanisms involving dynamic asymmetries of focal contacts, stress fibers, and intermediate filaments. Interestingly, cells do not pass these constricting zones when they contain a defective keratin fusion protein implicated in squamous cancer. By combining ratchetaxis with chemical gradients, we finally report that cells are sensitive to local asymmetries in confinement and that topological and chemical cues may be encoded differently by cells. Overall, our ratchet channels could mimic small blood vessels in which cells such as circulating tumor cells are confined; cells can probe local asymmetries that determine their entry into tissues and their subsequent direction. Our results shed light on invasion mechanisms in cancer.
Collapse
Affiliation(s)
- Emilie Le Maout
- Laboratory of Cell Physics ISIS/IGBMC, CNRS and University of Strasbourg, Strasbourg, France; Institut de Génétique et de Biologie Moléculaire et Cellulaire, Illkirch, France; Centre National de la Recherche Scientifique, Illkirch, France; Institut National de la Santé et de la Recherche Médicale, Illkirch, France; Université de Strasbourg, Illkirch, France
| | - Simon Lo Vecchio
- Laboratory of Cell Physics ISIS/IGBMC, CNRS and University of Strasbourg, Strasbourg, France; Institut de Génétique et de Biologie Moléculaire et Cellulaire, Illkirch, France; Centre National de la Recherche Scientifique, Illkirch, France; Institut National de la Santé et de la Recherche Médicale, Illkirch, France; Université de Strasbourg, Illkirch, France
| | - Praveen Kumar Korla
- Institute of Biomedical Sciences, National Sun Yatsen University, Kaohsiung, Taiwan; School of Chinese Medicine, China Medical University, Taichung, Taiwan
| | - Jim Jinn-Chyuan Sheu
- Institute of Biomedical Sciences, National Sun Yatsen University, Kaohsiung, Taiwan; School of Chinese Medicine, China Medical University, Taichung, Taiwan; Department of Health and Nutrition Biotechnology, Asia University, Taichung, Taiwan; Department of Biotechnology, Kaohsiung Medical University, Kaohsiung, Taiwan
| | - Daniel Riveline
- Laboratory of Cell Physics ISIS/IGBMC, CNRS and University of Strasbourg, Strasbourg, France; Institut de Génétique et de Biologie Moléculaire et Cellulaire, Illkirch, France; Centre National de la Recherche Scientifique, Illkirch, France; Institut National de la Santé et de la Recherche Médicale, Illkirch, France; Université de Strasbourg, Illkirch, France.
| |
Collapse
|
69
|
Marcelot A, Petitalot A, Ropars V, Le Du MH, Samson C, Dubois S, Hoffmann G, Miron S, Cuniasse P, Marquez JA, Thai R, Theillet FX, Zinn-Justin S. Di-phosphorylated BAF shows altered structural dynamics and binding to DNA, but interacts with its nuclear envelope partners. Nucleic Acids Res 2021; 49:3841-3855. [PMID: 33744941 PMCID: PMC8053085 DOI: 10.1093/nar/gkab184] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2020] [Revised: 02/05/2021] [Accepted: 03/06/2021] [Indexed: 02/07/2023] Open
Abstract
Barrier-to-autointegration factor (BAF), encoded by the BANF1 gene, is an abundant and ubiquitously expressed metazoan protein that has multiple functions during the cell cycle. Through its ability to cross-bridge two double-stranded DNA (dsDNA), it favours chromosome compaction, participates in post-mitotic nuclear envelope reassembly and is essential for the repair of large nuclear ruptures. BAF forms a ternary complex with the nuclear envelope proteins lamin A/C and emerin, and its interaction with lamin A/C is defective in patients with recessive accelerated aging syndromes. Phosphorylation of BAF by the vaccinia-related kinase 1 (VRK1) is a key regulator of BAF localization and function. Here, we demonstrate that VRK1 successively phosphorylates BAF on Ser4 and Thr3. The crystal structures of BAF before and after phosphorylation are extremely similar. However, in solution, the extensive flexibility of the N-terminal helix α1 and loop α1α2 in BAF is strongly reduced in di-phosphorylated BAF, due to interactions between the phosphorylated residues and the positively charged C-terminal helix α6. These regions are involved in DNA and lamin A/C binding. Consistently, phosphorylation causes a 5000-fold loss of affinity for dsDNA. However, it does not impair binding to lamin A/C Igfold domain and emerin nucleoplasmic region, which leaves open the question of the regulation of these interactions.
Collapse
Affiliation(s)
- Agathe Marcelot
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Sud, Université Paris-Saclay, Gif-sur-Yvette Cedex, France
| | - Ambre Petitalot
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Sud, Université Paris-Saclay, Gif-sur-Yvette Cedex, France
| | - Virginie Ropars
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Sud, Université Paris-Saclay, Gif-sur-Yvette Cedex, France
| | - Marie-Hélène Le Du
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Sud, Université Paris-Saclay, Gif-sur-Yvette Cedex, France
| | - Camille Samson
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Sud, Université Paris-Saclay, Gif-sur-Yvette Cedex, France
| | | | - Guillaume Hoffmann
- High Throughput Crystallization Lab, EMBL Grenoble Outstation, Grenoble Cedex, France
| | - Simona Miron
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Sud, Université Paris-Saclay, Gif-sur-Yvette Cedex, France
| | - Philippe Cuniasse
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Sud, Université Paris-Saclay, Gif-sur-Yvette Cedex, France
| | - Jose Antonio Marquez
- High Throughput Crystallization Lab, EMBL Grenoble Outstation, Grenoble Cedex, France
| | | | - François-Xavier Theillet
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Sud, Université Paris-Saclay, Gif-sur-Yvette Cedex, France
| | - Sophie Zinn-Justin
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Sud, Université Paris-Saclay, Gif-sur-Yvette Cedex, France
| |
Collapse
|
70
|
Abstract
Micronuclei are aberrant nuclear compartments that form when chromosomes or chromosome fragments fail to incorporate into a primary nucleus during mitotic exit. Ruptures at the micronuclear envelope are associated with DNA damage and activation of immune sensing pathways. To gain insights into these processes, we have developed a method to purify ruptured micronuclei. This method paves the way toward understanding the consequences of micronuclear envelope rupture. For complete details on the use and execution of this protocol, please refer to Mohr et al. (2021). An optimized protocol for purifying micronuclei with ruptured nuclear envelopes Use of fluorescent markers enables flow sorting of distinct populations of micronuclei Preservation of micronuclear protein and DNA content for functional characterization
Collapse
Affiliation(s)
| | - John Maciejowski
- Molecular Biology Program, Sloan Kettering Institute, New York, NY 10065, USA
| |
Collapse
|
71
|
Halfmann CT, Roux KJ. Barrier-to-autointegration factor: a first responder for repair of nuclear ruptures. Cell Cycle 2021; 20:647-660. [PMID: 33678126 DOI: 10.1080/15384101.2021.1892320] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
Abstract
The nuclear envelope (NE) is a critical barrier between the cytosol and nucleus that is key for compartmentalization within the cell and serves an essential role in organizing and protecting genomic DNA. Rupturing of the NE through loss of constitutive NE proteins and/or mechanical force applied to the nucleus results in the unregulated mixing of cytosolic and nuclear compartments, leading to DNA damage and genomic instability. Nuclear rupture has recently gained interest as a mechanism that may participate in various NE-associated diseases as well as cancer. Remarkably, these rupturing events are often transient, with cells being capable of rapidly repairing nuclear ruptures. Recently, we identified Barrier-to-Autointegration Factor (BAF), a DNA-binding protein involved in post-mitotic NE reformation and cytosolic viral regulation, as an essential protein for nuclear rupture repair. During interphase, the highly mobile cytosolic BAF is primed to monitor for a compromised NE by rapidly binding to newly exposed nuclear DNA and subsequently recruiting the factors necessary for NE repair. This review highlights the recent findings of BAF's roles in rupture repair, and offers perspectives on how regulatory factors that control BAF activity may potentially alter the cellular response to nuclear ruptures and how BAF may participate in human disease.
Collapse
Affiliation(s)
| | - Kyle J Roux
- Enabling Technologies Group, Sanford Research, Sioux Falls, SD, USA.,Department of Pediatrics, Sanford School of Medicine, University of South Dakota, Sioux Falls, SD, USA
| |
Collapse
|
72
|
Zhen Y, Radulovic M, Vietri M, Stenmark H. Sealing holes in cellular membranes. EMBO J 2021; 40:e106922. [PMID: 33644904 PMCID: PMC8013788 DOI: 10.15252/embj.2020106922] [Citation(s) in RCA: 66] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Revised: 10/29/2020] [Accepted: 11/04/2020] [Indexed: 12/11/2022] Open
Abstract
The compartmentalization of eukaryotic cells, which is essential for their viability and functions, is ensured by single or double bilayer membranes that separate the cell from the exterior and form boundaries between the cell’s organelles and the cytosol. Nascent nuclear envelopes and autophagosomes, which both are enveloped by double membranes, need to be sealed during the late stage of their biogenesis. On the other hand, the integrity of cellular membranes such as the plasma membrane, lysosomes and the nuclear envelope can be compromised by pathogens, chemicals, radiation, inflammatory responses and mechanical stress. There are cellular programmes that restore membrane integrity after injury. Here, we review cellular mechanisms that have evolved to maintain membrane integrity during organelle biogenesis and after injury, including membrane scission mediated by the endosomal sorting complex required for transport (ESCRT), vesicle patching and endocytosis.
Collapse
Affiliation(s)
- Yan Zhen
- Centre for Cancer Cell Reprogramming, Institute of Clinical Medicine, Faculty of Medicine, University of Oslo, Oslo, Norway.,Department of Molecular Cell Biology, Institute for Cancer Research, Oslo University Hospital, Oslo, Norway
| | - Maja Radulovic
- Centre for Cancer Cell Reprogramming, Institute of Clinical Medicine, Faculty of Medicine, University of Oslo, Oslo, Norway.,Department of Molecular Cell Biology, Institute for Cancer Research, Oslo University Hospital, Oslo, Norway
| | - Marina Vietri
- Centre for Cancer Cell Reprogramming, Institute of Clinical Medicine, Faculty of Medicine, University of Oslo, Oslo, Norway.,Department of Molecular Cell Biology, Institute for Cancer Research, Oslo University Hospital, Oslo, Norway
| | - Harald Stenmark
- Centre for Cancer Cell Reprogramming, Institute of Clinical Medicine, Faculty of Medicine, University of Oslo, Oslo, Norway.,Department of Molecular Cell Biology, Institute for Cancer Research, Oslo University Hospital, Oslo, Norway.,Faculty of Medicine and Health Sciences, Centre of Molecular Inflammation Research, Norwegian University of Science and Technology, Trondheim, Norway
| |
Collapse
|
73
|
Why Cells and Viruses Cannot Survive without an ESCRT. Cells 2021; 10:cells10030483. [PMID: 33668191 PMCID: PMC7995964 DOI: 10.3390/cells10030483] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2021] [Revised: 02/19/2021] [Accepted: 02/21/2021] [Indexed: 12/15/2022] Open
Abstract
Intracellular organelles enwrapped in membranes along with a complex network of vesicles trafficking in, out and inside the cellular environment are one of the main features of eukaryotic cells. Given their central role in cell life, compartmentalization and mechanisms allowing their maintenance despite continuous crosstalk among different organelles have been deeply investigated over the past years. Here, we review the multiple functions exerted by the endosomal sorting complex required for transport (ESCRT) machinery in driving membrane remodeling and fission, as well as in repairing physiological and pathological membrane damages. In this way, ESCRT machinery enables different fundamental cellular processes, such as cell cytokinesis, biogenesis of organelles and vesicles, maintenance of nuclear–cytoplasmic compartmentalization, endolysosomal activity. Furthermore, we discuss some examples of how viruses, as obligate intracellular parasites, have evolved to hijack the ESCRT machinery or part of it to execute/optimize their replication cycle/infection. A special emphasis is given to the herpes simplex virus type 1 (HSV-1) interaction with the ESCRT proteins, considering the peculiarities of this interplay and the need for HSV-1 to cross both the nuclear-cytoplasmic and the cytoplasmic-extracellular environment compartmentalization to egress from infected cells.
Collapse
|
74
|
Mohr L, Toufektchan E, von Morgen P, Chu K, Kapoor A, Maciejowski J. ER-directed TREX1 limits cGAS activation at micronuclei. Mol Cell 2021; 81:724-738.e9. [PMID: 33476576 PMCID: PMC7897315 DOI: 10.1016/j.molcel.2020.12.037] [Citation(s) in RCA: 94] [Impact Index Per Article: 31.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2020] [Revised: 11/18/2020] [Accepted: 12/18/2020] [Indexed: 02/06/2023]
Abstract
Micronuclei are aberrant nuclear compartments that can form as a result of chromosome mis-segregation. Frequent loss of micronuclear envelope integrity exposes DNA to the cytoplasm, leading to chromosome fragmentation and immune activation. Here, we use micronuclei purification to show that the endoplasmic reticulum (ER)-associated nuclease TREX1 inhibits cGAS activation at micronuclei by degrading micronuclear DNA upon micronuclear envelope rupture. We demonstrate that the ER accesses ruptured micronuclei and plays a critical role in enabling TREX1 nucleolytic attack. TREX1 mutations, previously implicated in immune disease, untether TREX1 from the ER, disrupt TREX1 localization to micronuclei, diminish micronuclear DNA damage, and enhance cGAS activation. These results establish ER-directed resection of micronuclear DNA by TREX1 as a critical regulator of cytosolic DNA sensing in chromosomally unstable cells and provide a mechanistic basis for the importance of TREX1 ER tethering in preventing autoimmunity.
Collapse
Affiliation(s)
- Lisa Mohr
- Molecular Biology Program, Sloan Kettering Institute, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA
| | - Eléonore Toufektchan
- Molecular Biology Program, Sloan Kettering Institute, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA
| | - Patrick von Morgen
- Molecular Biology Program, Sloan Kettering Institute, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA
| | - Kevan Chu
- Molecular Biology Program, Sloan Kettering Institute, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA
| | - Aakanksha Kapoor
- Molecular Biology Program, Sloan Kettering Institute, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA
| | - John Maciejowski
- Molecular Biology Program, Sloan Kettering Institute, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA.
| |
Collapse
|
75
|
Krupina K, Goginashvili A, Cleveland DW. Causes and consequences of micronuclei. Curr Opin Cell Biol 2021; 70:91-99. [PMID: 33610905 DOI: 10.1016/j.ceb.2021.01.004] [Citation(s) in RCA: 95] [Impact Index Per Article: 31.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2021] [Accepted: 01/14/2021] [Indexed: 12/14/2022]
Abstract
Micronuclei are small membrane-bounded compartments with a DNA content encapsulated by a nuclear envelope and spatially separated from the primary nucleus. Micronuclei have long been linked to chromosome instability, genome rearrangements, and mutagenesis. They are frequently found in cancers, during senescence, and after genotoxic stress. Compromised integrity of the micronuclear envelope delays or disrupts DNA replication, inhibits DNA repair, and exposes micronuclear DNA directly to cytoplasm. Micronuclei play a central role in tumorigenesis, with micronuclear DNA being a source of complex genome rearrangements (including chromothripsis) and promoting a cyclic GMP-AMP synthase (cGAS)-mediated cellular immune response that may contribute to cancer metastasis. Here, we discuss recent findings on how micronuclei are generated, what the consequences are, and what cellular mechanisms can be applied to protect against micronucleation.
Collapse
Affiliation(s)
- Ksenia Krupina
- Ludwig Institute for Cancer Research, University of California at San Diego, La Jolla, CA, 92093, USA; Department of Cellular and Molecular Medicine, University of California at San Diego, La Jolla, CA, 92093, USA
| | - Alexander Goginashvili
- Ludwig Institute for Cancer Research, University of California at San Diego, La Jolla, CA, 92093, USA; Department of Cellular and Molecular Medicine, University of California at San Diego, La Jolla, CA, 92093, USA
| | - Don W Cleveland
- Ludwig Institute for Cancer Research, University of California at San Diego, La Jolla, CA, 92093, USA; Department of Cellular and Molecular Medicine, University of California at San Diego, La Jolla, CA, 92093, USA.
| |
Collapse
|
76
|
Penfield L, Shankar R, Szentgyörgyi E, Laffitte A, Mauro MS, Audhya A, Müller-Reichert T, Bahmanyar S. Regulated lipid synthesis and LEM2/CHMP7 jointly control nuclear envelope closure. J Cell Biol 2021; 219:151636. [PMID: 32271860 PMCID: PMC7199858 DOI: 10.1083/jcb.201908179] [Citation(s) in RCA: 35] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2019] [Revised: 01/22/2020] [Accepted: 03/03/2020] [Indexed: 11/22/2022] Open
Abstract
The nuclear permeability barrier depends on closure of nuclear envelope (NE) holes. Here, we investigate closure of the NE opening surrounding the meiotic spindle in C. elegans oocytes. ESCRT-III components accumulate at the opening but are not required for nuclear closure on their own. 3D analysis revealed cytoplasmic membranes directly adjacent to NE holes containing meiotic spindle microtubules. We demonstrate that the NE protein phosphatase, CNEP-1/CTDNEP1, controls de novo glycerolipid synthesis through lipin to prevent invasion of excess ER membranes into NE holes and a defective NE permeability barrier. Loss of NE adaptors for ESCRT-III exacerbates ER invasion and nuclear permeability defects in cnep-1 mutants, suggesting that ESCRTs restrict excess ER membranes during NE closure. Restoring glycerolipid synthesis in embryos deleted for CNEP-1 and ESCRT components rescued NE permeability defects. Thus, regulating the production and feeding of ER membranes into NE holes together with ESCRT-mediated remodeling is required for nuclear closure.
Collapse
Affiliation(s)
- Lauren Penfield
- Department of Molecular, Cellular and Developmental Biology, New Haven, CT
| | - Raakhee Shankar
- Department of Biomolecular Chemistry, University of Wisconsin-Madison School of Medicine and Public Health, Madison, WI
| | - Erik Szentgyörgyi
- Experimental Center, Faculty of Medicine Carl Gustav Carus, Technische Universität Dresden, Dresden, Germany
| | - Alyssa Laffitte
- Department of Molecular, Cellular and Developmental Biology, New Haven, CT
| | - Michael Sean Mauro
- Department of Molecular, Cellular and Developmental Biology, New Haven, CT
| | - Anjon Audhya
- Department of Biomolecular Chemistry, University of Wisconsin-Madison School of Medicine and Public Health, Madison, WI
| | - Thomas Müller-Reichert
- Experimental Center, Faculty of Medicine Carl Gustav Carus, Technische Universität Dresden, Dresden, Germany
| | - Shirin Bahmanyar
- Department of Molecular, Cellular and Developmental Biology, New Haven, CT
| |
Collapse
|
77
|
Perea Paizal J, Au SH, Bakal C. Squeezing through the microcirculation: survival adaptations of circulating tumour cells to seed metastasis. Br J Cancer 2021; 124:58-65. [PMID: 33257836 PMCID: PMC7782506 DOI: 10.1038/s41416-020-01176-x] [Citation(s) in RCA: 35] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2020] [Revised: 11/02/2020] [Accepted: 11/03/2020] [Indexed: 12/20/2022] Open
Abstract
During metastasis, tumour cells navigating the vascular circulatory system-circulating tumour cells (CTCs)-encounter capillary beds, where they start the process of extravasation. Biomechanical constriction forces exerted by the microcirculation compromise the survival of tumour cells within capillaries, but a proportion of CTCs manage to successfully extravasate and colonise distant sites. Despite the profound importance of this step in the progression of metastatic cancers, the factors about this deadly minority of cells remain elusive. Growing evidence suggests that mechanical forces exerted by the capillaries might induce adaptive mechanisms in CTCs, enhancing their survival and metastatic potency. Advances in microfluidics have enabled a better understanding of the cell-survival capabilities adopted in capillary-mimicking constrictions. In this review, we will highlight adaptations developed by CTCs to endure mechanical constraints in the microvasculature and outline how these mechanical forces might trigger dynamic changes towards a more invasive phenotype. A better understanding of the dynamic mechanisms adopted by CTCs within the microcirculation that ultimately lead to metastasis could open up novel therapeutic avenues.
Collapse
Affiliation(s)
- Julia Perea Paizal
- Department of Bioengineering, Imperial College London, London, SW7 2AZ, UK.
- Division of Cancer Biology, Chester Beatty Laboratories, Institute of Cancer Research, 237 Fulham Road, London, SW6 6JB, UK.
- Cancer Research UK Convergence Science Centre, Roderic Hill Building, Imperial College London, London, SW7 2BB, UK.
| | - Sam H Au
- Department of Bioengineering, Imperial College London, London, SW7 2AZ, UK
- Cancer Research UK Convergence Science Centre, Roderic Hill Building, Imperial College London, London, SW7 2BB, UK
| | - Chris Bakal
- Division of Cancer Biology, Chester Beatty Laboratories, Institute of Cancer Research, 237 Fulham Road, London, SW6 6JB, UK.
- Cancer Research UK Convergence Science Centre, Roderic Hill Building, Imperial College London, London, SW7 2BB, UK.
| |
Collapse
|
78
|
Capella M, Martín Caballero L, Pfander B, Braun S, Jentsch S. ESCRT recruitment by the S. cerevisiae inner nuclear membrane protein Heh1 is regulated by Hub1-mediated alternative splicing. J Cell Sci 2020; 133:jcs250688. [PMID: 33262311 DOI: 10.1242/jcs.250688] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2020] [Accepted: 11/17/2020] [Indexed: 12/28/2022] Open
Abstract
Misassembled nuclear pore complexes (NPCs) are removed by sealing off the surrounding nuclear envelope (NE), which is conducted by the endosomal sorting complexes required for transport (ESCRT) machinery. Recruitment of ESCRT proteins to the NE is mediated by the interaction between the ESCRT member Chm7 and the inner nuclear membrane protein Heh1, which belongs to the conserved LEM family. Increased ESCRT recruitment results in excessive membrane scission at damage sites but its regulation remains poorly understood. Here, we show that Hub1-mediated alternative splicing of HEH1 pre-mRNA, resulting in production of its shorter form Heh1-S, is critical for the integrity of the NE in Saccharomyces cerevisiae ESCRT-III mutants lacking Hub1 or Heh1-S display severe growth defects and accumulate improperly assembled NPCs. This depends on the interaction of Chm7 with the conserved MSC domain, which is only present in the longer variant Heh1-L. Heh1 variants assemble into heterodimers, and we demonstrate that a unique splice segment in Heh1-S suppresses growth defects associated with the uncontrolled interaction between Heh1-L and Chm7. Together, our findings reveal that Hub1-mediated splicing generates Heh1-S to regulate ESCRT recruitment to the NE.This article has an associated First Person interview with the first author of the paper.
Collapse
Affiliation(s)
- Matías Capella
- Molecular Cell Biology, Max Planck Institute of Biochemistry, 82152 Martinsried, Germany
- Department of Physiological Chemistry, Biomedical Center (BMC), Ludwig Maximilians University of Munich, 82152 Martinsried, Germany
| | - Lucía Martín Caballero
- Department of Physiological Chemistry, Biomedical Center (BMC), Ludwig Maximilians University of Munich, 82152 Martinsried, Germany
- International Max Planck Research School for Molecular and Cellular Life Sciences, 82152 Martinsried, Germany
| | - Boris Pfander
- International Max Planck Research School for Molecular and Cellular Life Sciences, 82152 Martinsried, Germany
- DNA Replication and Genome Integrity, Max Planck Institute of Biochemistry, 82152 Martinsried, Germany
| | - Sigurd Braun
- Department of Physiological Chemistry, Biomedical Center (BMC), Ludwig Maximilians University of Munich, 82152 Martinsried, Germany
- International Max Planck Research School for Molecular and Cellular Life Sciences, 82152 Martinsried, Germany
| | - Stefan Jentsch
- Molecular Cell Biology, Max Planck Institute of Biochemistry, 82152 Martinsried, Germany
| |
Collapse
|
79
|
Hallmarks of Health. Cell 2020; 184:33-63. [PMID: 33340459 DOI: 10.1016/j.cell.2020.11.034] [Citation(s) in RCA: 227] [Impact Index Per Article: 56.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2020] [Revised: 09/09/2020] [Accepted: 11/19/2020] [Indexed: 12/16/2022]
Abstract
Health is usually defined as the absence of pathology. Here, we endeavor to define health as a compendium of organizational and dynamic features that maintain physiology. The biological causes or hallmarks of health include features of spatial compartmentalization (integrity of barriers and containment of local perturbations), maintenance of homeostasis over time (recycling and turnover, integration of circuitries, and rhythmic oscillations), and an array of adequate responses to stress (homeostatic resilience, hormetic regulation, and repair and regeneration). Disruption of any of these interlocked features is broadly pathogenic, causing an acute or progressive derailment of the system coupled to the loss of numerous stigmata of health.
Collapse
|
80
|
Unnikannan CP, Reuveny A, Grunberg D, Volk T. Recruitment of BAF to the nuclear envelope couples the LINC complex to endoreplication. Development 2020; 147:dev.191304. [PMID: 33168584 PMCID: PMC7758627 DOI: 10.1242/dev.191304] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2020] [Accepted: 10/29/2020] [Indexed: 12/21/2022]
Abstract
DNA endoreplication has been implicated as a cell strategy for cell growth and in tissue injury. Here, we demonstrate that barrier-to-autointegration factor (BAF) represses endoreplication in Drosophila myofibers. We show that BAF localization at the nuclear envelope is eliminated in flies with mutations of the linker of nucleoskeleton and cytoskeleton (LINC) complex in which the LEM-domain protein Otefin is excluded, or after disruption of the nucleus-sarcomere connections. Furthermore, BAF localization at the nuclear envelope requires the activity of the BAF kinase VRK1/Ball, and, consistently, non-phosphorylatable BAF-GFP is excluded from the nuclear envelope. Importantly, removal of BAF from the nuclear envelope correlates with increased DNA content in the myonuclei. E2F1, a key regulator of endoreplication, overlaps BAF localization at the myonuclear envelope, and BAF removal from the nuclear envelope results in increased E2F1 levels in the nucleoplasm and subsequent elevated DNA content. We suggest that LINC-dependent and phosphosensitive attachment of BAF to the nuclear envelope, through its binding to Otefin, tethers E2F1 to the nuclear envelope thus inhibiting its accumulation in the nucleoplasm. Summary: Localization of BAF at the nuclear envelope of myonuclei depends on a functional LINC complex and on nucleus-sarcomere connections, and is shown to restrict E2F1 levels in the nucleoplasm.
Collapse
Affiliation(s)
- C P Unnikannan
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Adriana Reuveny
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Dvorah Grunberg
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Talila Volk
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot 76100, Israel
| |
Collapse
|
81
|
O'Bryan CS, Zhang Q, Lele TP, Angelini TE. Mechanical Characterization of Glandular Acini Using a Micro-indentation Instrument. Bio Protoc 2020; 10:e3847. [PMID: 33889659 DOI: 10.21769/bioprotoc.3847] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2020] [Accepted: 10/09/2020] [Indexed: 11/02/2022] Open
Abstract
The linker of nucleoskeleton and cytoskeleton (LINC) complex is responsible for tethering the nucleus to the cytoskeleton, providing a pathway for the cell's nucleus to sense mechanical signals from the environment. Recently, we explored the role of the LINC complex in the development of glandular epithelial acini, such as those found in kidneys, breasts, and other organs. Acini developed with disrupted LINC complexes exhibited a loss of structural integrity, including filling of the lumen structures. As part of our investigation, we performed a mechanical indentation assay of LINC disrupted and undisrupted MDCK II cells using a micro-indentation instrument mounted above a laser-scanning confocal microscope. Through a combination of force measurements acquired from the micro-indentation instrument and contact area measurements taken from fluorescence images, we determined the average contact pressure at which the acini structure ruptured. Here, we provide a detailed description of the design of the micro-indentation instrument, as well as the experimental steps developed to perform these bio-indentation measurements. Furthermore, we discuss the data analysis steps necessary to determine the rupture pressure of the acini structures. While this protocol is focused on the indentation of individual glandular acini, the methods presented here can be adapted to perform a variety of mechanical indentation experiments for both 2D and 3D biological systems.
Collapse
Affiliation(s)
- Christopher S O'Bryan
- Department of Mechanical and Aerospace Engineering, University of Florida, Gainesville, FL, USA.,Department of Chemical and Biological Engineering, University of Pennsylvania, Philadelphia, PA, USA
| | - Qiao Zhang
- Department of Chemical Engineering, University of Florida, Gainesville, FL, USA
| | - Tanmay P Lele
- Department of Chemical Engineering, University of Florida, Gainesville, FL, USA
| | - Thomas E Angelini
- Department of Mechanical and Aerospace Engineering, University of Florida, Gainesville, FL, USA.,J. Crayton Pruitt Department of Biomedical Engineering, University of Florida, Gainesville, FL, USA
| |
Collapse
|
82
|
Burla R, La Torre M, Maccaroni K, Verni F, Giunta S, Saggio I. Interplay of the nuclear envelope with chromatin in physiology and pathology. Nucleus 2020; 11:205-218. [PMID: 32835589 PMCID: PMC7529417 DOI: 10.1080/19491034.2020.1806661] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2020] [Revised: 07/30/2020] [Accepted: 08/03/2020] [Indexed: 12/21/2022] Open
Abstract
The nuclear envelope compartmentalizes chromatin in eukaryotic cells. The main nuclear envelope components are lamins that associate with a panoply of factors, including the LEM domain proteins. The nuclear envelope of mammalian cells opens up during cell division. It is reassembled and associated with chromatin at the end of mitosis when telomeres tether to the nuclear periphery. Lamins, LEM domain proteins, and DNA binding factors, as BAF, contribute to the reorganization of chromatin. In this context, an emerging role is that of the ESCRT complex, a machinery operating in multiple membrane assembly pathways, including nuclear envelope reformation. Research in this area is unraveling how, mechanistically, ESCRTs link to nuclear envelope associated factors as LEM domain proteins. Importantly, ESCRTs work also during interphase for repairing nuclear envelope ruptures. Altogether the advances in this field are giving new clues for the interpretation of diseases implicating nuclear envelope fragility, as laminopathies and cancer. ABBREVIATIONS na, not analyzed; ko, knockout; kd, knockdown; NE, nuclear envelope; LEM, LAP2-emerin-MAN1 (LEM)-domain containing proteins; LINC, linker of nucleoskeleton and cytoskeleton complexes; Cyt, cytoplasm; Chr, chromatin; MB, midbody; End, endosomes; Tel, telomeres; INM, inner nuclear membrane; NP, nucleoplasm; NPC, Nuclear Pore Complex; ER, Endoplasmic Reticulum; SPB, spindle pole body.
Collapse
Affiliation(s)
- Romina Burla
- Department of Biology and Biotechnology, Sapienza University of Rome, Rome, Italy
- CNR Institute of Molecular Biology and Pathology, Italy
| | - Mattia La Torre
- Department of Biology and Biotechnology, Sapienza University of Rome, Rome, Italy
| | - Klizia Maccaroni
- Department of Biology and Biotechnology, Sapienza University of Rome, Rome, Italy
| | - Fiammetta Verni
- Department of Biology and Biotechnology, Sapienza University of Rome, Rome, Italy
| | - Simona Giunta
- Department of Biology and Biotechnology, Sapienza University of Rome, Rome, Italy
- Rockefeller University, New York, NY, USA
| | - Isabella Saggio
- Department of Biology and Biotechnology, Sapienza University of Rome, Rome, Italy
- CNR Institute of Molecular Biology and Pathology, Italy
- Institute of Structural Biology, School of Biological Sciences, Nanyang Technological University, Singapore, Singapore
| |
Collapse
|
83
|
Molenberghs F, Bogers JJ, De Vos WH. Confined no more: Viral mechanisms of nuclear entry and egress. Int J Biochem Cell Biol 2020; 129:105875. [PMID: 33157236 DOI: 10.1016/j.biocel.2020.105875] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2020] [Revised: 10/27/2020] [Accepted: 10/29/2020] [Indexed: 12/14/2022]
Abstract
Viruses are obligatory intracellular parasites. For their efficient replication, many require access to the nuclear interior. Yet, only few viral particles are small enough to passively diffuse through the nuclear pore complexes, calling for alternative strategies to bypass the nuclear envelope barrier. Some viruses will await mitotic nuclear envelope breakdown to gain access, whereas others will exploit more active means, for instance by hijacking nuclear pore transport or by directly targeting constituents of the nuclear envelope so as to remodel and temporarily perturb its integrity. After replication, newly produced viral DNA complexes need to cross the same barrier to exit the nucleus and enter the cytoplasm, where the final stages of virion maturation take place. There are also different flavours to the feat of nuclear egress that vary in delicacy and intensity. In this review, we define the major entry and egress strategies that are exploited by different viruses and describe the molecular details thereof. Ultimately, a deeper understanding of these pathways may help identifying molecular targets for blocking viral reproduction or spreading.
Collapse
Affiliation(s)
- Freya Molenberghs
- Laboratory of Cell Biology and Histology, Department of Veterinary Sciences/Medicine and Health Sciences, University of Antwerp, Belgium
| | - Johannes J Bogers
- Laboratory of Cell Biology and Histology, Department of Veterinary Sciences/Medicine and Health Sciences, University of Antwerp, Belgium
| | - Winnok H De Vos
- Laboratory of Cell Biology and Histology, Department of Veterinary Sciences/Medicine and Health Sciences, University of Antwerp, Belgium.
| |
Collapse
|
84
|
Jacquet K, Rodrigue MA, Richard DE, Lavoie JN. The adenoviral protein E4orf4: a probing tool to decipher mechanical stress-induced nuclear envelope remodeling in tumor cells. Cell Cycle 2020; 19:2963-2981. [PMID: 33103553 DOI: 10.1080/15384101.2020.1836441] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022] Open
Abstract
The human adenovirus (Ad) type 2/5 early region 4 (E4) ORF4 protein (E4orf4) exerts a remarkable tumor cell-selective killing activity in mammalian cells. This indicates that E4orf4 can target tumor cell-defining features and is a unique tool to probe cancer cell vulnerabilities. Recently, we found that E4orf4, through an interaction with the polarity protein PAR3, subverts nuclear envelope (NE) remodeling processes in a tumor cell-selective manner. In this Perspective, we outline mechanical signals that modify nuclear dynamics and tumor cell behavior to highlight potential mechanisms for E4orf4's tumoricidal activity. Through an analysis of E4orf4's cellular targets, we define a protein subnetwork that comprises phosphatase systems interconnected to polarity protein hubs, which could contribute to enhanced NE plasticity. We infer that elucidating E4orf4's protein network at a functional level could uncover key mechanisms of NE remodeling that define the tumor cell phenotype.
Collapse
Affiliation(s)
- Kévin Jacquet
- Centre de Recherche sur le Cancer de l'Université Laval , Québec, Canada.,Oncology, Centre de Recherche du CHU de Québec-Université Laval , Québec, Canada
| | - Marc-Antoine Rodrigue
- Centre de Recherche sur le Cancer de l'Université Laval , Québec, Canada.,Oncology, Centre de Recherche du CHU de Québec-Université Laval , Québec, Canada
| | - Darren E Richard
- Centre de Recherche sur le Cancer de l'Université Laval , Québec, Canada.,Département de Biologie Moléculaire, Biochimie Médicale et Pathologie, Université Laval , Québec, Canada.,Endocrinology and Nephrology, Centre de Recherche du CHU de Québec-Université Laval , Québec, Canada
| | - Josée N Lavoie
- Centre de Recherche sur le Cancer de l'Université Laval , Québec, Canada.,Oncology, Centre de Recherche du CHU de Québec-Université Laval , Québec, Canada.,Département de Biologie Moléculaire, Biochimie Médicale et Pathologie, Université Laval , Québec, Canada
| |
Collapse
|
85
|
Warecki B, Ling X, Bast I, Sullivan W. ESCRT-III-mediated membrane fusion drives chromosome fragments through nuclear envelope channels. J Cell Biol 2020; 219:133702. [PMID: 32032426 PMCID: PMC7054997 DOI: 10.1083/jcb.201905091] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2019] [Revised: 11/05/2019] [Accepted: 12/18/2019] [Indexed: 12/24/2022] Open
Abstract
Mitotic cells must form a single nucleus during telophase or exclude part of their genome as damage-prone micronuclei. While research has detailed how micronuclei arise from cells entering anaphase with lagging chromosomes, cellular mechanisms allowing late-segregating chromosomes to rejoin daughter nuclei remain underexplored. Here, we find that late-segregating acentric chromosome fragments that rejoin daughter nuclei are associated with nuclear membrane but devoid of lamin and nuclear pore complexes in Drosophila melanogaster. We show that acentrics pass through membrane-, lamin-, and nuclear pore-based channels in the nuclear envelope that extend and retract as acentrics enter nuclei. Membrane encompassing the acentrics fuses with the nuclear membrane, facilitating integration of the acentrics into newly formed nuclei. Fusion, mediated by the membrane fusion protein Comt/NSF and ESCRT-III components Shrub/CHMP4B and CHMP2B, facilitates reintegration of acentrics into nuclei. These results suggest a previously unsuspected role for membrane fusion, similar to nuclear repair, in the formation of a single nucleus during mitotic exit and the maintenance of genomic integrity.
Collapse
Affiliation(s)
- Brandt Warecki
- Department of Molecular, Cell, and Developmental Biology, University of California, Santa Cruz, Santa Cruz, CA
| | - Xi Ling
- Department of Molecular, Cell, and Developmental Biology, University of California, Santa Cruz, Santa Cruz, CA
| | - Ian Bast
- Department of Molecular, Cell, and Developmental Biology, University of California, Santa Cruz, Santa Cruz, CA
| | - William Sullivan
- Department of Molecular, Cell, and Developmental Biology, University of California, Santa Cruz, Santa Cruz, CA
| |
Collapse
|
86
|
Abstract
The nuclear envelope is often depicted as a static barrier that regulates access between the nucleus and the cytosol. However, recent research has identified many conditions in cultured cells and in vivo in which nuclear membrane ruptures cause the loss of nuclear compartmentalization. These conditions include some that are commonly associated with human disease, such as migration of cancer cells through small spaces and expression of nuclear lamin disease mutations in both cultured cells and tissues undergoing nuclear migration. Nuclear membrane ruptures are rapidly repaired in the nucleus but persist in nuclear compartments that form around missegregated chromosomes called micronuclei. This review summarizes what is known about the mechanisms of nuclear membrane rupture and repair in both the main nucleus and micronuclei, and highlights recent work connecting the loss of nuclear integrity to genome instability and innate immune signaling. These connections link nuclear membrane rupture to complex chromosome alterations, tumorigenesis, and laminopathy etiologies.
Collapse
Affiliation(s)
- John Maciejowski
- Molecular Biology Program, Sloan Kettering Institute, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA;
| | - Emily M Hatch
- Division of Basic Sciences and Human Biology, The Fred Hutchinson Cancer Research Center, Seattle, Washington 98109, USA;
| |
Collapse
|
87
|
Marcelot A, Worman HJ, Zinn-Justin S. Protein structural and mechanistic basis of progeroid laminopathies. FEBS J 2020; 288:2757-2772. [PMID: 32799420 DOI: 10.1111/febs.15526] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2020] [Accepted: 07/30/2020] [Indexed: 12/14/2022]
Abstract
Progeroid laminopathies are characterized by the premature appearance of certain signs of physiological aging in a subset of tissues. They are caused by mutations in genes coding for A-type lamins or lamin-binding proteins. Here, we review how different mutations causing progeroid laminopathies alter protein structure or protein-protein interactions and how these impact on mechanisms that protect cell viability and function. One group of progeroid laminopathies, which includes Hutchinson-Gilford progeria syndrome, is characterized by accumulation of unprocessed prelamin A or variants. These are caused by mutations in the A-type lamin gene (LMNA), altering prelamin A itself, or in ZMPSTE24, encoding an endoprotease involved in its processing. The abnormally expressed farnesylated proteins impact on various cellular processes that may contribute to progeroid phenotypes. Other LMNA mutations lead to the production of nonfarnesylated A-type lamin variants with amino acid substitutions in solvent-exposed hot spots located mainly in coil 1B and the immunoglobulin fold domain. Dominant missense mutations might reinforce interactions between lamin domains, thus giving rise to excessively stabilized filament networks. Recessive missense mutations in A-type lamins and barrier-to-autointegration factor (BAF) causing progeroid disorders are found at the interface between these interacting proteins. The amino acid changes decrease the binding affinity of A-type lamins for BAF, which may contribute to lamina disorganization, as well as defective repair of mechanically induced nuclear envelope rupture. Targeting these molecular alterations in A-type lamins and associated proteins identified through structural biology studies could facilitate the design of therapeutic strategies to treat patients with rare but severe progeroid laminopathies.
Collapse
Affiliation(s)
- Agathe Marcelot
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Uni Paris-Sud, Uni Paris-Saclay, Gif-sur-Yvette Cedex, France
| | - Howard J Worman
- Department of Medicine and Department of Pathology and Cell Biology, Vagelos College of Physicians and Surgeons, Columbia University, New York, NY, USA
| | - Sophie Zinn-Justin
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Uni Paris-Sud, Uni Paris-Saclay, Gif-sur-Yvette Cedex, France
| |
Collapse
|
88
|
Sears RM, Roux KJ. Diverse cellular functions of barrier-to-autointegration factor and its roles in disease. J Cell Sci 2020; 133:133/16/jcs246546. [PMID: 32817163 DOI: 10.1242/jcs.246546] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Barrier-to-autointegration factor (BAF; encoded by BANF1) is a small highly conserved, ubiquitous and self-associating protein that coordinates with numerous binding partners to accomplish several key cellular processes. By interacting with double-stranded DNA, histones and various other nuclear proteins, including those enriched at the nuclear envelope, BAF appears to be essential for replicating cells to protect the genome and enable cell division. Cellular processes, such as innate immunity, post-mitotic nuclear reformation, repair of interphase nuclear envelope rupture, genomic regulation, and the DNA damage and repair response have all been shown to depend on BAF. This Review focuses on the regulation of the numerous interactions of BAF, which underlie the mechanisms by which BAF accomplishes its essential cellular functions. We will also discuss how perturbation of BAF function may contribute to human disease.
Collapse
Affiliation(s)
- Rhiannon M Sears
- Enabling Technologies Group, Sanford Research, Sioux Falls, SD 57104, USA.,Basic Biomedical Sciences, Sanford School of Medicine, University of South Dakota, Vermillion, SD 57069, USA
| | - Kyle J Roux
- Enabling Technologies Group, Sanford Research, Sioux Falls, SD 57104, USA .,Department of Pediatrics, Sanford School of Medicine, University of South Dakota, Sioux Falls, SD 57069, USA
| |
Collapse
|
89
|
Nuclear mechanosensing: mechanism and consequences of a nuclear rupture. Mutat Res 2020; 821:111717. [PMID: 32810711 DOI: 10.1016/j.mrfmmm.2020.111717] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2020] [Revised: 06/25/2020] [Accepted: 07/14/2020] [Indexed: 12/22/2022]
Abstract
The physical connections between the cytoskeletal system and the nucleus provide a route for the nucleus to sense the mechanical stress both inside and outside of the cell. Failure to withstand such stress leads to nuclear rupture, which is observed in human diseases. In this review, we will go through the recent findings and our current understandings of nuclear rupture. Starting with the triggers of nuclear rupture, including the aberrant nuclear lamina composition and the elevated actomyosin contractility. We will also discuss the role of ESCRT-III in nuclear rupture repair and the biological consequences of nuclear rupture, including the negative impacts on cellular compartmentalization, DNA damage, and cellular differentiation. Recent studies on nuclear rupture provide further insights into the direct mechanistic link between nuclear rupture and several pathological conditions. Such knowledge can guide us in developing potential therapeutic solutions for the patients.
Collapse
|
90
|
Abstract
During closed mitosis in fission yeast, growing microtubules push onto the nuclear envelope to deform it, which results in fission into two daughter nuclei. The resistance of the envelope to bending, quantified by the flexural stiffness, helps determine the microtubule-dependent nuclear shape transformations. Computational models of envelope mechanics have assumed values of the flexural stiffness of the envelope based on simple scaling arguments. The validity of these estimates is in doubt, however, owing to the complex structure of the nuclear envelope. Here, we performed computational analysis of the bending of the nuclear envelope under applied force using a model that accounts for envelope geometry. Our calculations show that the effective bending modulus of the nuclear envelope is an order of magnitude larger than a single membrane and approximately five times greater than the nuclear lamina. This large bending modulus is in part due to the 45 nm separation between the two membranes, which supports larger bending moments in the structure. Further, the effective bending modulus is highly sensitive to the geometry of the nuclear envelope, ranging from twofold to an order magnitude larger than the corresponding single membrane. These results suggest that spatial variations in geometry and mechanical environment of the envelope may cause a spatial distribution of flexural stiffness in the same nucleus. Overall, our calculations support the possibility that the nuclear envelope may balance significant mechanical stresses in yeast and in cells from higher organisms.
Collapse
Affiliation(s)
- Ashutosh Agrawal
- Department of Mechanical Engineering, University of Houston, Houston, TX 77204
| | - Tanmay P Lele
- Department of Biomedical Engineering and Department of Chemical Engineering, Texas A&M University, College Station, TX 77843
| |
Collapse
|
91
|
Guo X, Dai X, Wu X, Zhou T, Ni J, Xue J, Wang X. Understanding the birth of rupture-prone and irreparable micronuclei. Chromosoma 2020; 129:181-200. [PMID: 32671520 DOI: 10.1007/s00412-020-00741-w] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2020] [Revised: 06/30/2020] [Accepted: 07/02/2020] [Indexed: 12/17/2022]
Abstract
Micronuclei are extra-nuclear bodies mainly derived from ana-telophase lagging chromosomes/chromatins (LCs) that are not incorporated into primary nuclei at mitotic exit. Unlike primary nuclei, most micronuclei are enclosed by nuclear envelope (NE) that is highly susceptible to spontaneous and irreparable rupture. Ruptured micronuclei act as triggers of chromothripsis-like chaotic chromosomal rearrangements and cGAS-mediated innate immunity and inflammation, raising the view that micronuclei play active roles in human aging and tumorigenesis. Thus, understanding the ways in which micronuclear envelope (mNE) goes awry acquires increased importance. Here, we review the data to present a general framework for this question. We firstly describe NE reassembly after mitosis and NE repair during interphase. Simultaneously, we briefly discuss how mNE is organized and how mNE rupture controls the fate of micronuclei and micronucleated cells. As a focus of this review, we highlight current knowledge about why mNE is rupture-prone and irreparable. For this, we survey observations from a series of elegant studies to provide a systematic overview. We conclude that the birth of rupture-prone and irreparable micronuclei may be the cumulative effects of their intracellular geographic origins, biophysical properties, and specific mNE features. We propose that DNA damage and immunogenicity in micronuclei increase stepwise from altered mNE components, mNE rupture, and refractory to repair. Throughout our discussion, we note interesting issues in mNE fragility that have yet to be resolved.
Collapse
Affiliation(s)
- Xihan Guo
- School of Life Sciences, The Engineering Research Center of Sustainable Development and Utilization of Biomass Energy, Yunnan Normal University, Kunming, 650500, Yunnan, China
| | - Xueqin Dai
- State Key Laboratory of Genetic Resources and Evolution, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, 650223, Yunnan, China
- Kunming College of Life Science, University of Chinese Academy of Sciences, Kunming, 650204, Yunnan, China
- University of the Chinese Academy of Sciences, Beijing, 100049, China
| | - Xue Wu
- School of Life Sciences, The Engineering Research Center of Sustainable Development and Utilization of Biomass Energy, Yunnan Normal University, Kunming, 650500, Yunnan, China
| | - Tao Zhou
- School of Life Sciences, The Engineering Research Center of Sustainable Development and Utilization of Biomass Energy, Yunnan Normal University, Kunming, 650500, Yunnan, China
| | - Juan Ni
- School of Life Sciences, The Engineering Research Center of Sustainable Development and Utilization of Biomass Energy, Yunnan Normal University, Kunming, 650500, Yunnan, China
| | - Jinglun Xue
- State Key Laboratory of Genetic Engineering, Institute of Genetics, School of Life Sciences, Fudan University, Shanghai, 200433, China
| | - Xu Wang
- School of Life Sciences, The Engineering Research Center of Sustainable Development and Utilization of Biomass Energy, Yunnan Normal University, Kunming, 650500, Yunnan, China.
| |
Collapse
|
92
|
Unrestrained ESCRT-III drives micronuclear catastrophe and chromosome fragmentation. Nat Cell Biol 2020; 22:856-867. [PMID: 32601372 DOI: 10.1038/s41556-020-0537-5] [Citation(s) in RCA: 70] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2019] [Accepted: 05/24/2020] [Indexed: 12/11/2022]
Abstract
The ESCRT-III membrane fission machinery maintains the integrity of the nuclear envelope. Although primary nuclei resealing takes minutes, micronuclear envelope ruptures seem to be irreversible. Instead, micronuclear ruptures result in catastrophic membrane collapse and are associated with chromosome fragmentation and chromothripsis, complex chromosome rearrangements thought to be a major driving force in cancer development. Here we use a combination of live microscopy and electron tomography, as well as computer simulations, to uncover the mechanism underlying micronuclear collapse. We show that, due to their small size, micronuclei inherently lack the capacity of primary nuclei to restrict the accumulation of CHMP7-LEMD2, a compartmentalization sensor that detects loss of nuclear integrity. This causes unrestrained ESCRT-III accumulation, which drives extensive membrane deformation, DNA damage and chromosome fragmentation. Thus, the nuclear-integrity surveillance machinery is a double-edged sword, as its sensitivity ensures rapid repair at primary nuclei while causing unrestrained activity at ruptured micronuclei, with catastrophic consequences for genome stability.
Collapse
|
93
|
Lusk CP, Ader NR. CHMPions of repair: Emerging perspectives on sensing and repairing the nuclear envelope barrier. Curr Opin Cell Biol 2020; 64:25-33. [PMID: 32105978 PMCID: PMC7371540 DOI: 10.1016/j.ceb.2020.01.011] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2019] [Revised: 01/20/2020] [Accepted: 01/22/2020] [Indexed: 12/20/2022]
Abstract
Understanding how the integrity of the nuclear membranes is protected against internal and external stresses is an emergent challenge. Work reviewed here investigated the mechanisms by which losses of nuclear-cytoplasmic compartmentalization are sensed and ameliorated. Fundamental to these is spatial control over interactions between the endosomal sorting complexes required for transport machinery and LAP2-emerin-MAN1 family inner nuclear membrane proteins, which together promote nuclear envelope sealing in interphase and at the end of mitosis. We suggest that the size of the nuclear envelope hole dictates the mechanism of its repair, with larger holes requiring barrier-to-autointegration factor and the potential triggering of a postmitotic nuclear envelope reassembly pathway in interphase. We also consider why these mechanisms fail at ruptured micronuclei. Together, this work re-emphasizes the need to understand how membrane flow and local lipid metabolism help ensure that the nuclear envelope is refractory to mechanical rupture yet fluid enough to allow its essential dynamics.
Collapse
Affiliation(s)
- C Patrick Lusk
- Department of Cell Biology, Yale School of Medicine, 295 Congress Avenue, New Haven, CT, 06520, USA.
| | - Nicholas R Ader
- Department of Cell Biology, Yale School of Medicine, 295 Congress Avenue, New Haven, CT, 06520, USA
| |
Collapse
|
94
|
von Appen A, LaJoie D, Johnson IE, Trnka MJ, Pick SM, Burlingame AL, Ullman KS, Frost A. LEM2 phase separation promotes ESCRT-mediated nuclear envelope reformation. Nature 2020; 582:115-118. [PMID: 32494070 PMCID: PMC7321842 DOI: 10.1038/s41586-020-2232-x] [Citation(s) in RCA: 84] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2019] [Accepted: 02/26/2020] [Indexed: 01/01/2023]
Abstract
During cell division, remodelling of the nuclear envelope enables chromosome segregation by the mitotic spindle1. The reformation of sealed nuclei requires ESCRTs (endosomal sorting complexes required for transport) and LEM2, a transmembrane ESCRT adaptor2-4. Here we show how the ability of LEM2 to condense on microtubules governs the activation of ESCRTs and coordinated spindle disassembly. The LEM motif of LEM2 binds BAF, conferring on LEM2 an affinity for chromatin5,6, while an adjacent low-complexity domain (LCD) promotes LEM2 phase separation. A proline-arginine-rich sequence within the LCD binds to microtubules and targets condensation of LEM2 to spindle microtubules that traverse the nascent nuclear envelope. Furthermore, the winged-helix domain of LEM2 activates the ESCRT-II/ESCRT-III hybrid protein CHMP7 to form co-oligomeric rings. Disruption of these events in human cells prevented the recruitment of downstream ESCRTs, compromised spindle disassembly, and led to defects in nuclear integrity and DNA damage. We propose that during nuclear reassembly LEM2 condenses into a liquid-like phase and coassembles with CHMP7 to form a macromolecular O-ring seal at the confluence between membranes, chromatin and the spindle. The properties of LEM2 described here, and the homologous architectures of related inner nuclear membrane proteins7,8, suggest that phase separation may contribute to other critical envelope functions, including interphase repair8-13 and chromatin organization14-17.
Collapse
Affiliation(s)
- Alexander von Appen
- Department of Biochemistry and Biophysics, University of California, San Francisco, CA, USA
| | - Dollie LaJoie
- Department of Oncological Sciences, Huntsman Cancer Institute, University of Utah, Salt Lake City, UT, USA
| | - Isabel E Johnson
- Department of Biochemistry and Biophysics, University of California, San Francisco, CA, USA
| | - Michael J Trnka
- Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, CA, USA
| | - Sarah M Pick
- Faculty of Chemistry and Pharmacy, University of Freiburg, Freiburg, Germany
| | - Alma L Burlingame
- Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, CA, USA
| | - Katharine S Ullman
- Department of Oncological Sciences, Huntsman Cancer Institute, University of Utah, Salt Lake City, UT, USA.
| | - Adam Frost
- Department of Biochemistry and Biophysics, University of California, San Francisco, CA, USA.
- Chan Zuckerberg Biohub, San Francisco, CA, USA.
- Quantitative Biosciences Institute, University of California, San Francisco, San Francisco, CA, USA.
| |
Collapse
|
95
|
Lee IJ, Stokasimov E, Dempsey N, Varberg JM, Jacob E, Jaspersen SL, Pellman D. Factors promoting nuclear envelope assembly independent of the canonical ESCRT pathway. J Cell Biol 2020; 219:e201908232. [PMID: 32243490 PMCID: PMC7265314 DOI: 10.1083/jcb.201908232] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2019] [Revised: 01/11/2020] [Accepted: 03/03/2020] [Indexed: 01/15/2023] Open
Abstract
The nuclear envelope (NE) undergoes dynamic remodeling to maintain NE integrity, a process involving the inner nuclear membrane protein LEM2 recruiting CHMP7/Cmp7 and then ESCRT-III. However, prior work has hinted at CHMP7/ESCRT-independent mechanisms. To identify such mechanisms, we studied NE assembly in Schizosaccharomyces japonicus, a fission yeast that undergoes partial mitotic NE breakdown and reassembly. S. japonicus cells lacking Cmp7 have compromised NE sealing after mitosis but are viable. A genetic screen identified mutations that promote NE integrity in cmp7Δ cells. Unexpectedly, loss of Lem2 or its interacting partner Nur1 suppressed cmp7Δ defects. In the absence of Cmp7, Lem2 formed aggregates that appear to interfere with ESCRT-independent NE sealing. A gain-of-function mutation implicated a membrane and ESCRT-III regulator, Alx1, in this alternate pathway. Additional results suggest a potentially general role for unsaturated fatty acids in NE integrity. These findings establish the existence of mechanisms for NE sealing independent of the canonical ESCRT pathway.
Collapse
Affiliation(s)
- I-Ju Lee
- Department of Pediatric Oncology, Dana-Farber Cancer Institute, Boston, MA
- Department of Cell Biology, Harvard Medical School, Boston, MA
| | - Ema Stokasimov
- Department of Pediatric Oncology, Dana-Farber Cancer Institute, Boston, MA
- Department of Cell Biology, Harvard Medical School, Boston, MA
| | - Nathaniel Dempsey
- Department of Pediatric Oncology, Dana-Farber Cancer Institute, Boston, MA
- Department of Cell Biology, Harvard Medical School, Boston, MA
| | | | - Etai Jacob
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA
| | - Sue L. Jaspersen
- Stowers Institute for Medical Research, Kansas City, MO
- Department of Molecular and Integrative Physiology, University of Kansas Medical Center, Kansas City, KS
| | - David Pellman
- Department of Pediatric Oncology, Dana-Farber Cancer Institute, Boston, MA
- Department of Cell Biology, Harvard Medical School, Boston, MA
- Howard Hughes Medical Institute, Chevy Chase, MD
| |
Collapse
|
96
|
Young AM, Gunn AL, Hatch EM. BAF facilitates interphase nuclear membrane repair through recruitment of nuclear transmembrane proteins. Mol Biol Cell 2020; 31:1551-1560. [PMID: 32459568 PMCID: PMC7521799 DOI: 10.1091/mbc.e20-01-0009] [Citation(s) in RCA: 51] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Nuclear membrane rupture during interphase occurs in a variety of cell contexts, both healthy and pathological. Membrane ruptures can be rapidly repaired, but these mechanisms are still unclear. Here we show barrier-to-autointegration factor (BAF), a nuclear envelope protein that shapes chromatin and recruits membrane proteins in mitosis, also facilitates nuclear membrane repair in interphase, in part through recruitment of the nuclear membrane proteins emerin and Lem-domain-containing protein 2 (LEMD2) to rupture sites. Characterization of GFP-BAF accumulation at nuclear membrane rupture sites confirmed BAF is a fast, accurate, and persistent mark of nucleus rupture whose kinetics are partially dictated by membrane resealing. BAF depletion significantly delayed nuclear membrane repair, with a larger effect on longer ruptures. This phenotype could be rescued by GFP-BAF, but not by a BAF mutant lacking the Lap2, emerin, Man1 (LEM)-protein binding domain. Depletion of the BAF interactors LEMD2 or emerin, and to a lesser extent lamin A/C, increased the duration of nucleus ruptures, consistent with LEM-protein binding being a key function of BAF during membrane repair. Overall our results suggest a model where BAF is critical for timely repair of large ruptures in the nuclear membrane, potentially by facilitating membrane attachment to the rupture site.
Collapse
Affiliation(s)
- Alexandra M Young
- Division of Basic Sciences and Human Biology, Fred Hutchinson Cancer Research Center, Seattle, WA 98109
| | - Amanda L Gunn
- Division of Basic Sciences and Human Biology, Fred Hutchinson Cancer Research Center, Seattle, WA 98109
| | - Emily M Hatch
- Division of Basic Sciences and Human Biology, Fred Hutchinson Cancer Research Center, Seattle, WA 98109
| |
Collapse
|
97
|
Duan T, Kitzman SC, Geyer PK. Survival of Drosophila germline stem cells requires the chromatin-binding protein Barrier-to-autointegration factor. Development 2020; 147:dev.186171. [PMID: 32345742 DOI: 10.1242/dev.186171] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2019] [Accepted: 03/31/2020] [Indexed: 11/20/2022]
Abstract
The nuclear lamina (NL) is an extensive protein network that underlies the inner nuclear envelope. This network includes LAP2-emerin-MAN1 domain (LEM-D) proteins that associate with the chromatin and DNA-binding protein Barrier-to-autointegration factor (BAF). Here, we investigate the partnership between three NL Drosophila LEM-D proteins and BAF. In most tissues, only Emerin/Otefin is required for NL enrichment of BAF, revealing an unexpected dependence on a single LEM-D protein. Prompted by these observations, we studied BAF contributions in the ovary, a tissue where Emerin/Otefin function is essential. We show that germ cell-specific BAF knockdown causes phenotypes that mirror emerin/otefin mutants. Loss of BAF disrupts NL structure, blocks differentiation and promotes germ cell loss, phenotypes that are partially rescued by inactivation of the ATR and Chk2 kinases. These data suggest that, similar to emerin/otefin mutants, BAF depletion activates the NL checkpoint that causes germ cell loss. Taken together, our findings provide evidence for a prominent NL partnership between the LEM-D protein Emerin/Otefin and BAF, revealing that BAF functions with this partner in the maintenance of an adult stem cell population.
Collapse
Affiliation(s)
- Tingting Duan
- Department of Biochemistry, University of Iowa, Iowa City, IA 52242, USA
| | - S Cole Kitzman
- Department of Biochemistry, University of Iowa, Iowa City, IA 52242, USA
| | - Pamela K Geyer
- Department of Biochemistry, University of Iowa, Iowa City, IA 52242, USA
| |
Collapse
|
98
|
Martins F, Sousa J, Pereira CD, Cruz e Silva OAB, Rebelo S. Nuclear envelope dysfunction and its contribution to the aging process. Aging Cell 2020; 19:e13143. [PMID: 32291910 PMCID: PMC7253059 DOI: 10.1111/acel.13143] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2020] [Revised: 02/28/2020] [Accepted: 03/09/2020] [Indexed: 12/25/2022] Open
Abstract
The nuclear envelope (NE) is the central organizing unit of the eukaryotic cell serving as a genome protective barrier and mechanotransduction interface between the cytoplasm and the nucleus. The NE is mainly composed of a nuclear lamina and a double membrane connected at specific points where the nuclear pore complexes (NPCs) form. Physiological aging might be generically defined as a functional decline across lifespan observed from the cellular to organismal level. Therefore, during aging and premature aging, several cellular alterations occur, including nuclear‐specific changes, particularly, altered nuclear transport, increased genomic instability induced by DNA damage, and telomere attrition. Here, we highlight and discuss proteins associated with nuclear transport dysfunction induced by aging, particularly nucleoporins, nuclear transport factors, and lamins. Moreover, changes in the structure of chromatin and consequent heterochromatin rearrangement upon aging are discussed. These alterations correlate with NE dysfunction, particularly lamins’ alterations. Finally, telomere attrition is addressed and correlated with altered levels of nuclear lamins and nuclear lamina‐associated proteins. Overall, the identification of molecular mechanisms underlying NE dysfunction, including upstream and downstream events, which have yet to be unraveled, will be determinant not only to our understanding of several pathologies, but as here discussed, in the aging process.
Collapse
Affiliation(s)
- Filipa Martins
- Neuroscience and Signaling Laboratory Institute of Biomedicine (iBiMED) Department of Medical Sciences University of Aveiro Aveiro Portugal
| | - Jéssica Sousa
- Neuroscience and Signaling Laboratory Institute of Biomedicine (iBiMED) Department of Medical Sciences University of Aveiro Aveiro Portugal
| | - Cátia D. Pereira
- Neuroscience and Signaling Laboratory Institute of Biomedicine (iBiMED) Department of Medical Sciences University of Aveiro Aveiro Portugal
| | - Odete A. B. Cruz e Silva
- Neuroscience and Signaling Laboratory Institute of Biomedicine (iBiMED) Department of Medical Sciences University of Aveiro Aveiro Portugal
- The Discoveries CTR Aveiro Portugal
| | - Sandra Rebelo
- Neuroscience and Signaling Laboratory Institute of Biomedicine (iBiMED) Department of Medical Sciences University of Aveiro Aveiro Portugal
| |
Collapse
|
99
|
Stephens AD. Chromatin rigidity provides mechanical and genome protection. Mutat Res 2020; 821:111712. [PMID: 32590202 PMCID: PMC8186544 DOI: 10.1016/j.mrfmmm.2020.111712] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2020] [Revised: 06/05/2020] [Accepted: 06/15/2020] [Indexed: 12/31/2022]
Abstract
The nucleus is the organelle in the cell that contains the genome and its associate proteins which is collectively called chromatin. New work has shown that chromatin and its compaction level, dictated largely through histone modification state, provides rigidity to protect and stabilize the nucleus. Alterations in chromatin, its mechanics, and downstream loss of nuclear shape and stability are hallmarks of human disease. Weakened nuclear mechanics and abnormal morphology have been shown to cause rupturing of the nucleus which results in nuclear dysfunction including DNA damage. Thus, the rigidity provided by chromatin to maintain nuclear mechanical stability also provides its own protection from DNA damage via compartmentalization maintenance.
Collapse
Affiliation(s)
- Andrew D Stephens
- Biology Department, University of Massachusetts Amherst, Amherst, MA, 01003, United States.
| |
Collapse
|
100
|
K6-linked SUMOylation of BAF regulates nuclear integrity and DNA replication in mammalian cells. Proc Natl Acad Sci U S A 2020; 117:10378-10387. [PMID: 32332162 PMCID: PMC7229763 DOI: 10.1073/pnas.1912984117] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Barrier-to-autointegration factor (BAF) is a highly conserved protein in metazoans that has multiple functions during the cell cycle. We found that BAF is SUMOylated at K6, and that this modification is essential for its nuclear localization and function, including nuclear integrity maintenance and DNA replication. K6-linked SUMOylation of BAF promotes binding and interaction with lamin A/C to regulate nuclear integrity. K6-linked SUMOylation of BAF also supports BAF binding to DNA and proliferating cell nuclear antigen and regulates DNA replication. SENP1 and SENP2 catalyze the de-SUMOylation of BAF at K6. Disrupting the SUMOylation and de-SUMOylation cycle of BAF at K6 not only disturbs nuclear integrity, but also induces DNA replication failure. Taken together, our findings demonstrate that SUMOylation at K6 is an important regulatory mechanism that governs the nuclear functions of BAF in mammalian cells.
Collapse
|