1
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van der Graaf K, Srivastav S, Nishad R, Stern M, McNew JA. The Drosophila Nesprin-1 homolog MSP300 is required for muscle autophagy and proteostasis. J Cell Sci 2024; 137:jcs262096. [PMID: 38757366 PMCID: PMC11213522 DOI: 10.1242/jcs.262096] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2024] [Accepted: 05/13/2024] [Indexed: 05/18/2024] Open
Abstract
Nesprin proteins, which are components of the linker of nucleoskeleton and cytoskeleton (LINC) complex, are located within the nuclear envelope and play prominent roles in nuclear architecture. For example, LINC complex proteins interact with both chromatin and the cytoskeleton. Here, we report that the Drosophila Nesprin MSP300 has an additional function in autophagy within larval body wall muscles. RNAi-mediated MSP300 knockdown in larval body wall muscles resulted in defects in the contractile apparatus, muscle degeneration and defective autophagy. In particular, MSP300 knockdown caused accumulation of cytoplasmic aggregates that contained poly-ubiquitylated cargo, as well as the autophagy receptor ref(2)P (the fly homolog of p62 or SQSTM) and Atg8a. Furthermore, MSP300 knockdown larvae expressing an mCherry-GFP-tagged Atg8a transgene exhibited aberrant persistence of the GFP signal within these aggregates, indicating failure of autophagosome maturation. These autophagy deficits were similar to those exhibited by loss of the endoplasmic reticulum (ER) fusion protein Atlastin (Atl), raising the possibility that Atl and MSP300 might function in the same pathway. In support of this possibility, we found that a GFP-tagged MSP300 protein trap exhibited extensive localization to the ER. Alteration of ER-directed MSP300 might abrogate important cytoskeletal contacts necessary for autophagosome completion.
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Affiliation(s)
| | | | - Rajkishor Nishad
- Department of BioSciences, Rice University, Houston, TX 77005, USA
| | - Michael Stern
- Department of BioSciences, Rice University, Houston, TX 77005, USA
| | - James A. McNew
- Department of BioSciences, Rice University, Houston, TX 77005, USA
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2
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Bougaran P, Bautch VL. Life at the crossroads: the nuclear LINC complex and vascular mechanotransduction. Front Physiol 2024; 15:1411995. [PMID: 38831796 PMCID: PMC11144885 DOI: 10.3389/fphys.2024.1411995] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2024] [Accepted: 05/02/2024] [Indexed: 06/05/2024] Open
Abstract
Vascular endothelial cells line the inner surface of all blood vessels, where they are exposed to polarized mechanical forces throughout their lifespan. Both basal substrate interactions and apical blood flow-induced shear stress regulate blood vessel development, remodeling, and maintenance of vascular homeostasis. Disruption of these interactions leads to dysfunction and vascular pathologies, although how forces are sensed and integrated to affect endothelial cell behaviors is incompletely understood. Recently the endothelial cell nucleus has emerged as a prominent force-transducing organelle that participates in vascular mechanotransduction, via communication to and from cell-cell and cell-matrix junctions. The LINC complex, composed of SUN and nesprin proteins, spans the nuclear membranes and connects the nuclear lamina, the nuclear envelope, and the cytoskeleton. Here we review LINC complex involvement in endothelial cell mechanotransduction, describe unique and overlapping functions of each LINC complex component, and consider emerging evidence that two major SUN proteins, SUN1 and SUN2, orchestrate a complex interplay that extends outward to cell-cell and cell-matrix junctions and inward to interactions within the nucleus and chromatin. We discuss these findings in relation to vascular pathologies such as Hutchinson-Gilford progeria syndrome, a premature aging disorder with cardiovascular impairment. More knowledge of LINC complex regulation and function will help to understand how the nucleus participates in endothelial cell force sensing and how dysfunction leads to cardiovascular disease.
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Affiliation(s)
- Pauline Bougaran
- Department of Biology, The University of North Carolina, Chapel Hill, NC, United States
| | - Victoria L. Bautch
- Department of Biology, The University of North Carolina, Chapel Hill, NC, United States
- McAllister Heart Institute, The University of North Carolina, Chapel Hill, NC, United States
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3
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Niraula D, El Naqa I, Tuszynski JA, Gatenby RA. Modeling non-genetic information dynamics in cells using reservoir computing. iScience 2024; 27:109614. [PMID: 38632985 PMCID: PMC11022048 DOI: 10.1016/j.isci.2024.109614] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2024] [Revised: 03/15/2024] [Accepted: 03/26/2024] [Indexed: 04/19/2024] Open
Abstract
Virtually all cells use energy-driven, ion-specific membrane pumps to maintain large transmembrane gradients of Na+, K+, Cl-, Mg++, and Ca++, but the corresponding evolutionary benefit remains unclear. We propose that these gradients enable a dynamic and versatile biological system that acquires, analyzes, and responds to environmental information. We hypothesize that environmental signals are transmitted into the cell by ion fluxes along pre-existing gradients through gated ion-specific membrane channels. The consequent changes in cytoplasmic ion concentration can generate a local response or orchestrate global/regional cellular dynamics through wire-like ion fluxes along pre-existing and self-assembling cytoskeleton to engage the endoplasmic reticulum, mitochondria, and nucleus.
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Affiliation(s)
- Dipesh Niraula
- Department of Machine Learning, Moffitt Cancer Center, Tampa, FL, USA
| | - Issam El Naqa
- Department of Machine Learning, Moffitt Cancer Center, Tampa, FL, USA
| | - Jack Adam Tuszynski
- Departments of Physics and Oncology, University of Alberta, Edmonton, AB, Canada
- Department of Data Science and Engineering, The Silesian University of Technology, 44-100 Gliwice, Poland
- Department of Mechanical and Aerospace Engineering, Politecnico di Torino, Turin 10129, Italy
| | - Robert A. Gatenby
- Departments of Radiology and Integrated Mathematical Oncology, Moffitt Cancer Center, Tampa, FL, USA
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4
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Park JG, Jeon H, Hwang KY, Cha SS, Han RT, Cho H, Lee IG. Cargo specificity, regulation, and therapeutic potential of cytoplasmic dynein. Exp Mol Med 2024; 56:827-835. [PMID: 38556551 PMCID: PMC11059388 DOI: 10.1038/s12276-024-01200-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2023] [Revised: 01/05/2024] [Accepted: 01/10/2024] [Indexed: 04/02/2024] Open
Abstract
Intracellular retrograde transport in eukaryotic cells relies exclusively on the molecular motor cytoplasmic dynein 1. Unlike its counterpart, kinesin, dynein has a single isoform, which raises questions about its cargo specificity and regulatory mechanisms. The precision of dynein-mediated cargo transport is governed by a multitude of factors, including temperature, phosphorylation, the microtubule track, and interactions with a family of activating adaptor proteins. Activating adaptors are of particular importance because they not only activate the unidirectional motility of the motor but also connect a diverse array of cargoes with the dynein motor. Therefore, it is unsurprising that dysregulation of the dynein-activating adaptor transport machinery can lead to diseases such as spinal muscular atrophy, lower extremity, and dominant. Here, we discuss dynein motor motility within cells and in in vitro, and we present several methodologies employed to track the motion of the motor. We highlight several newly identified activating adaptors and their roles in regulating dynein. Finally, we explore the potential therapeutic applications of manipulating dynein transport to address diseases linked to dynein malfunction.
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Affiliation(s)
- Jin-Gyeong Park
- Biomedical Research Division, Korea Institute of Science and Technology, Seoul, 02792, South Korea
- Department of Biotechnology, College of Life Sciences and Biotechnology, Korea University, Seoul, 02841, South Korea
| | - Hanul Jeon
- Biomedical Research Division, Korea Institute of Science and Technology, Seoul, 02792, South Korea
- Department of Chemistry & Nanoscience, Ewha Womans University, Seoul, 03760, South Korea
| | - Kwang Yeon Hwang
- Department of Biotechnology, College of Life Sciences and Biotechnology, Korea University, Seoul, 02841, South Korea
| | - Sun-Shin Cha
- Department of Chemistry & Nanoscience, Ewha Womans University, Seoul, 03760, South Korea
| | - Rafael T Han
- Biomedical Research Division, Korea Institute of Science and Technology, Seoul, 02792, South Korea
- KHU-KIST Department of Converging Science and Technology, Kyunghee University, Seoul, 02447, South Korea
| | - Hyesung Cho
- Extreme Materials Research Center, Korea Institute of Science and Technology, Seoul, 02792, South Korea
| | - In-Gyun Lee
- Biomedical Research Division, Korea Institute of Science and Technology, Seoul, 02792, South Korea.
- Department of Biological Chemistry, University of Science and Technology, Daejeon, 34113, South Korea.
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5
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Mishra J, Chakraborty S, Niharika, Roy A, Manna S, Baral T, Nandi P, Patra SK. Mechanotransduction and epigenetic modulations of chromatin: Role of mechanical signals in gene regulation. J Cell Biochem 2024; 125:e30531. [PMID: 38345428 DOI: 10.1002/jcb.30531] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2023] [Revised: 01/08/2024] [Accepted: 01/26/2024] [Indexed: 03/12/2024]
Abstract
Mechanical forces may be generated within a cell due to tissue stiffness, cytoskeletal reorganization, and the changes (even subtle) in the cell's physical surroundings. These changes of forces impose a mechanical tension within the intracellular protein network (both cytosolic and nuclear). Mechanical tension could be released by a series of protein-protein interactions often facilitated by membrane lipids, lectins and sugar molecules and thus generate a type of signal to drive cellular processes, including cell differentiation, polarity, growth, adhesion, movement, and survival. Recent experimental data have accentuated the molecular mechanism of this mechanical signal transduction pathway, dubbed mechanotransduction. Mechanosensitive proteins in the cell's plasma membrane discern the physical forces and channel the information to the cell interior. Cells respond to the message by altering their cytoskeletal arrangement and directly transmitting the signal to the nucleus through the connection of the cytoskeleton and nucleoskeleton before the information despatched to the nucleus by biochemical signaling pathways. Nuclear transmission of the force leads to the activation of chromatin modifiers and modulation of the epigenetic landscape, inducing chromatin reorganization and gene expression regulation; by the time chemical messengers (transcription factors) arrive into the nucleus. While significant research has been done on the role of mechanotransduction in tumor development and cancer progression/metastasis, the mechanistic basis of force-activated carcinogenesis is still enigmatic. Here, in this review, we have discussed the various cues and molecular connections to better comprehend the cellular mechanotransduction pathway, and we also explored the detailed role of some of the multiple players (proteins and macromolecular complexes) involved in mechanotransduction. Thus, we have described an avenue: how mechanical stress directs the epigenetic modifiers to modulate the epigenome of the cells and how aberrant stress leads to the cancer phenotype.
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Affiliation(s)
- Jagdish Mishra
- Epigenetics and Cancer Research Laboratory, Department of Life Science, Biochemistry and Molecular Biology Group, National Institute of Technology, Rourkela, Odisha, India
| | - Subhajit Chakraborty
- Epigenetics and Cancer Research Laboratory, Department of Life Science, Biochemistry and Molecular Biology Group, National Institute of Technology, Rourkela, Odisha, India
| | - Niharika
- Epigenetics and Cancer Research Laboratory, Department of Life Science, Biochemistry and Molecular Biology Group, National Institute of Technology, Rourkela, Odisha, India
| | - Ankan Roy
- Epigenetics and Cancer Research Laboratory, Department of Life Science, Biochemistry and Molecular Biology Group, National Institute of Technology, Rourkela, Odisha, India
| | - Soumen Manna
- Epigenetics and Cancer Research Laboratory, Department of Life Science, Biochemistry and Molecular Biology Group, National Institute of Technology, Rourkela, Odisha, India
| | - Tirthankar Baral
- Epigenetics and Cancer Research Laboratory, Department of Life Science, Biochemistry and Molecular Biology Group, National Institute of Technology, Rourkela, Odisha, India
| | - Piyasa Nandi
- Epigenetics and Cancer Research Laboratory, Department of Life Science, Biochemistry and Molecular Biology Group, National Institute of Technology, Rourkela, Odisha, India
| | - Samir K Patra
- Epigenetics and Cancer Research Laboratory, Department of Life Science, Biochemistry and Molecular Biology Group, National Institute of Technology, Rourkela, Odisha, India
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6
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Tang Y. Plant nuclear envelope as a hub connecting genome organization with regulation of gene expression. Nucleus 2023; 14:2178201. [PMID: 36794966 PMCID: PMC9980628 DOI: 10.1080/19491034.2023.2178201] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/17/2023] Open
Abstract
Eukaryotic cells organize their genome within the nucleus with a double-layered membrane structure termed the nuclear envelope (NE) as the physical barrier. The NE not only shields the nuclear genome but also spatially separates transcription from translation. Proteins of the NE including nucleoskeleton proteins, inner nuclear membrane proteins, and nuclear pore complexes have been implicated in interacting with underlying genome and chromatin regulators to establish a higher-order chromatin architecture. Here, I summarize recent advances in the knowledge of NE proteins that are involved in chromatin organization, gene regulation, and coordination of transcription and mRNA export. These studies support an emerging view of plant NE as a central hub that contributes to chromatin organization and gene expression in response to various cellular and environmental cues.
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Affiliation(s)
- Yu Tang
- Peking University Institute of Advanced Agricultural Sciences, Shandong Laboratory of Advanced Agricultural Sciences at Weifang, Weifang, Shandong, China,CONTACT Yu Tang Peking University Institute of Advanced Agricultural Sciences, Shandong Laboratory of Advanced Agricultural Sciences at Weifang, Weifang, China
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7
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Pancheri NM, Daw JT, Ditton D, Schiele NR, Birks S, Uzer G, Jones CL, Penney BT, Theodossiou SK. The LINC complex regulates Achilles tendon elastic modulus, Achilles and tail tendon collagen crimp, and Achilles and tail tendon lateral expansion during early postnatal development. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.11.13.566892. [PMID: 38014288 PMCID: PMC10680625 DOI: 10.1101/2023.11.13.566892] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2023]
Abstract
There is limited understanding of how mechanical signals regulate tendon development. The nucleus has emerged as a major regulator of cellular mechanosensation, via the linker of nucleoskeleton and cytoskeleton (LINC) protein complex. Specific roles of LINC in tenogenesis have not been explored. In this study, we investigate how LINC regulates tendon development by disabling LINC-mediated mechanosensing via dominant negative (dn) expression of the Klarsicht, ANC-1, and Syne Homology (KASH) domain, which is necessary for LINC to function. We hypothesized that LINC regulates mechanotransduction in developing tendon, and that disabling LINC would impact tendon mechanical properties and structure in a mouse model of dnKASH. We used Achilles (AT) and tail (TT) tendons as representative energy-storing and limb-positioning tendons, respectively. Mechanical testing at postnatal day 10 showed that disabling the LINC complex via dnKASH significantly impacted tendon mechanical properties and cross-sectional area, and that effects differed between ATs and TTs. Collagen crimp distance was also impacted in dnKASH tendons, and was significantly decreased in ATs, and increased in TTs. Overall, we show that disruption to the LINC complex specifically impacts tendon mechanics and collagen crimp structure, with unique responses between an energy-storing and limb-positioning tendon. This suggests that nuclear mechanotransduction through LINC plays a role in regulating tendon formation during neonatal development.
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8
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Liu Z, Wang Q, Zhang J, Qi S, Duan Y, Li C. The Mechanotransduction Signaling Pathways in the Regulation of Osteogenesis. Int J Mol Sci 2023; 24:14326. [PMID: 37762629 PMCID: PMC10532275 DOI: 10.3390/ijms241814326] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2023] [Revised: 09/14/2023] [Accepted: 09/19/2023] [Indexed: 09/29/2023] Open
Abstract
Bones are constantly exposed to mechanical forces from both muscles and Earth's gravity to maintain bone homeostasis by stimulating bone formation. Mechanotransduction transforms external mechanical signals such as force, fluid flow shear, and gravity into intracellular responses to achieve force adaptation. However, the underlying molecular mechanisms on the conversion from mechanical signals into bone formation has not been completely defined yet. In the present review, we provide a comprehensive and systematic description of the mechanotransduction signaling pathways induced by mechanical stimuli during osteogenesis and address the different layers of interconnections between different signaling pathways. Further exploration of mechanotransduction would benefit patients with osteoporosis, including the aging population and postmenopausal women.
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Affiliation(s)
- Zhaoshuo Liu
- School of Engineering Medicine, Beihang University, Beijing 100191, China
- School of Biological Science and Medical Engineering, Beihang University, Beijing 100191, China
| | - Qilin Wang
- School of Engineering Medicine, Beihang University, Beijing 100191, China
- School of Biological Science and Medical Engineering, Beihang University, Beijing 100191, China
| | - Junyou Zhang
- School of Engineering Medicine, Beihang University, Beijing 100191, China
- School of Biological Science and Medical Engineering, Beihang University, Beijing 100191, China
| | - Sihan Qi
- School of Engineering Medicine, Beihang University, Beijing 100191, China
- School of Biological Science and Medical Engineering, Beihang University, Beijing 100191, China
| | - Yingying Duan
- School of Engineering Medicine, Beihang University, Beijing 100191, China
- School of Biological Science and Medical Engineering, Beihang University, Beijing 100191, China
| | - Chunyan Li
- School of Engineering Medicine, Beihang University, Beijing 100191, China
- School of Biological Science and Medical Engineering, Beihang University, Beijing 100191, China
- Key Laboratory of Big Data-Based Precision Medicine (Ministry of Industry and Information Technology), Beihang University, Beijing 100191, China
- Beijing Advanced Innovation Center for Big Data-Based Precision Medicine, Beihang University, Beijing 100191, China
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9
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Sharma R, Hetzer MW. Disulfide bond in SUN2 regulates dynamic remodeling of LINC complexes at the nuclear envelope. Life Sci Alliance 2023; 6:e202302031. [PMID: 37188462 PMCID: PMC10193101 DOI: 10.26508/lsa.202302031] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2023] [Revised: 05/02/2023] [Accepted: 05/02/2023] [Indexed: 05/17/2023] Open
Abstract
The LINC complex tethers the cell nucleus to the cytoskeleton to regulate mechanical forces during cell migration, differentiation, and various diseases. The function of LINC complexes relies on the interaction between highly conserved SUN and KASH proteins that form higher-order assemblies capable of load bearing. These structural details have emerged from in vitro assembled LINC complexes; however, the principles of in vivo assembly remain obscure. Here, we report a conformation-specific SUN2 antibody as a tool to visualize LINC complex dynamics in situ. Using imaging, biochemical, and cellular methods, we find that conserved cysteines in SUN2 undergo KASH-dependent inter- and intra-molecular disulfide bond rearrangements. Disruption of the SUN2 terminal disulfide bond compromises SUN2 localization, turnover, LINC complex assembly in addition to cytoskeletal organization and cell migration. Moreover, using pharmacological and genetic perturbations, we identify components of the ER lumen as SUN2 cysteines redox state regulators. Overall, we provide evidence for SUN2 disulfide bond rearrangement as a physiologically relevant structural modification that regulates LINC complex functions.
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Affiliation(s)
- Rahul Sharma
- Molecular and Cell Biology Laboratory, Salk Institute for Biological Studies, La Jolla, CA, USA
| | - Martin W Hetzer
- Molecular and Cell Biology Laboratory, Salk Institute for Biological Studies, La Jolla, CA, USA
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10
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Vidak S, Serebryannyy LA, Pegoraro G, Misteli T. Activation of endoplasmic reticulum stress in premature aging via the inner nuclear membrane protein SUN2. Cell Rep 2023; 42:112534. [PMID: 37210724 DOI: 10.1016/j.celrep.2023.112534] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2022] [Revised: 03/08/2023] [Accepted: 05/03/2023] [Indexed: 05/23/2023] Open
Abstract
One of the major cellular mechanisms to ensure cellular protein homeostasis is the endoplasmic reticulum (ER) stress response. This pathway is triggered by accumulation of misfolded proteins in the ER lumen. The ER stress response is also activated in the premature aging disease Hutchinson-Gilford progeria syndrome (HGPS). Here, we explore the mechanism of activation of the ER stress response in HGPS. We find that aggregation of the diseases-causing progerin protein at the nuclear envelope triggers ER stress. Induction of ER stress is dependent on the inner nuclear membrane protein SUN2 and its ability to cluster in the nuclear membrane. Our observations suggest that the presence of nucleoplasmic protein aggregates can be sensed, and signaled to the ER lumen, via clustering of SUN2. These results identify a mechanism of communication between the nucleus and the ER and provide insight into the molecular disease mechanisms of HGPS.
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Affiliation(s)
- Sandra Vidak
- National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | | | - Gianluca Pegoraro
- National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Tom Misteli
- National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA.
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11
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Shah PP, Santini GT, Shen KM, Jain R. InterLINCing Chromatin Organization and Mechanobiology in Laminopathies. Curr Cardiol Rep 2023; 25:307-314. [PMID: 37052760 PMCID: PMC10185580 DOI: 10.1007/s11886-023-01853-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 02/22/2023] [Indexed: 04/14/2023]
Abstract
PURPOSE OF REVIEW In this review, we explore the chromatin-related consequences of laminopathy-linked mutations through the lens of mechanotransduction. RECENT FINDINGS Multiple studies have highlighted the role of the nuclear lamina in maintaining the integrity of the nucleus. The lamina also has a critical role in 3D genome organization. Mutations in lamina proteins associated with various laminopathies result in the loss of organization of DNA at the nuclear periphery. However, it remains unclear if or how these two aspects of lamin function are connected. Recent data suggests that unlinking the cytoskeleton from the nuclear lamina may be beneficial to slow progress of deleterious phenotypes observed in laminopathies. In this review, we highlight emerging data that suggest interlinked chromatin- and mechanical biology-related pathways are interconnected in the pathogenesis of laminopathies.
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Affiliation(s)
- Parisha P. Shah
- Departments of Medicine and Cell and Developmental Biology, Penn Cardiovascular Institute, Penn Epigenetics Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104 USA
- Smilow Center for Translational Research, 09-184, 3400 Civic Center Blvd., Philadelphia, PA 19104 USA
| | - Garrett T. Santini
- Departments of Medicine and Cell and Developmental Biology, Penn Cardiovascular Institute, Penn Epigenetics Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104 USA
| | - Kaitlyn M. Shen
- Departments of Medicine and Cell and Developmental Biology, Penn Cardiovascular Institute, Penn Epigenetics Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104 USA
| | - Rajan Jain
- Departments of Medicine and Cell and Developmental Biology, Penn Cardiovascular Institute, Penn Epigenetics Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104 USA
- Smilow Center for Translational Research, 09-101, 3400 Civic Center Blvd., Philadelphia, PA 19104 USA
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12
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van der Graaf K, Srivastav S, Singh P, McNew JA, Stern M. The Drosophila melanogaster attP40 docking site and derivatives are insertion mutations of msp-300. PLoS One 2022; 17:e0278598. [PMID: 36516171 PMCID: PMC9750024 DOI: 10.1371/journal.pone.0278598] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Accepted: 11/19/2022] [Indexed: 12/15/2022] Open
Abstract
The ɸC31 integrase system is widely used in Drosophila melanogaster to allow transgene targeting to specific loci. Over the years, flies bearing any of more than 100 attP docking sites have been constructed. One popular docking site, termed attP40, is located close to the Nesprin-1 orthologue msp-300 and lies upstream of certain msp-300 isoforms and within the first intron of others. Here we show that attP40 causes larval muscle nuclear clustering, which is a phenotype also conferred by msp-300 mutations. We also show that flies bearing insertions within attP40 can exhibit decreased msp-300 transcript levels in third instar larvae. Finally, chromosomes carrying certain "transgenic RNAi project" (TRiP) insertions into attP40 can confer pupal or adult inviability or infertility, or dominant nuclear clustering effects in certain genetic backgrounds. These phenotypes do not require transcription from the insertions within attP40. These results demonstrate that attP40 and insertion derivatives act as msp-300 insertional mutations. These findings should be considered when interpreting data from attP40-bearing flies.
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Affiliation(s)
- Kevin van der Graaf
- Department of Biosciences, Program in Biochemistry and Cell Biology, Rice University, Houston, Texas, United States of America
| | - Saurabh Srivastav
- Department of Biosciences, Program in Biochemistry and Cell Biology, Rice University, Houston, Texas, United States of America
| | - Pratibha Singh
- Department of Biosciences, Program in Biochemistry and Cell Biology, Rice University, Houston, Texas, United States of America
| | - James A. McNew
- Department of Biosciences, Program in Biochemistry and Cell Biology, Rice University, Houston, Texas, United States of America
| | - Michael Stern
- Department of Biosciences, Program in Biochemistry and Cell Biology, Rice University, Houston, Texas, United States of America
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13
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Shaw NM, Rios-Monterrosa JL, Fedorchak GR, Ketterer MR, Coombs GS, Lammerding J, Wallrath LL. Effects of mutant lamins on nucleo-cytoskeletal coupling in Drosophila models of LMNA muscular dystrophy. Front Cell Dev Biol 2022; 10:934586. [PMID: 36120560 PMCID: PMC9471154 DOI: 10.3389/fcell.2022.934586] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2022] [Accepted: 07/20/2022] [Indexed: 11/13/2022] Open
Abstract
The nuclei of multinucleated skeletal muscles experience substantial external force during development and muscle contraction. Protection from such forces is partly provided by lamins, intermediate filaments that form a scaffold lining the inner nuclear membrane. Lamins play a myriad of roles, including maintenance of nuclear shape and stability, mediation of nuclear mechanoresponses, and nucleo-cytoskeletal coupling. Herein, we investigate how disease-causing mutant lamins alter myonuclear properties in response to mechanical force. This was accomplished via a novel application of a micropipette harpooning assay applied to larval body wall muscles of Drosophila models of lamin-associated muscular dystrophy. The assay enables the measurement of both nuclear deformability and intracellular force transmission between the cytoskeleton and nuclear interior in intact muscle fibers. Our studies revealed that specific mutant lamins increase nuclear deformability while other mutant lamins cause nucleo-cytoskeletal coupling defects, which were associated with loss of microtubular nuclear caging. We found that microtubule caging of the nucleus depended on Msp300, a KASH domain protein that is a component of the linker of nucleoskeleton and cytoskeleton (LINC) complex. Taken together, these findings identified residues in lamins required for connecting the nucleus to the cytoskeleton and suggest that not all muscle disease-causing mutant lamins produce similar defects in subcellular mechanics.
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Affiliation(s)
- Nicholas M. Shaw
- Department of Biochemistry, Carver College of Medicine, University of Iowa, Iowa City, IA, United States
| | - Jose L. Rios-Monterrosa
- Department of Biochemistry, Carver College of Medicine, University of Iowa, Iowa City, IA, United States
| | - Gregory R. Fedorchak
- The Nancy E. and Peter C. Meinig School of Biomedical Engineering, Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, NY, United States
| | - Margaret R. Ketterer
- Department of Biochemistry, Carver College of Medicine, University of Iowa, Iowa City, IA, United States
| | - Gary S. Coombs
- Biology Department, Waldorf University, Forest City, IA, United States
| | - Jan Lammerding
- The Nancy E. and Peter C. Meinig School of Biomedical Engineering, Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, NY, United States
| | - Lori L. Wallrath
- Department of Biochemistry, Carver College of Medicine, University of Iowa, Iowa City, IA, United States
- *Correspondence: Lori L. Wallrath,
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14
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Abstract
Lamins interact with a host of nuclear membrane proteins, transcription factors, chromatin regulators, signaling molecules, splicing factors, and even chromatin itself to form a nuclear subcompartment, the nuclear lamina, that is involved in a variety of cellular processes such as the governance of nuclear integrity, nuclear positioning, mitosis, DNA repair, DNA replication, splicing, signaling, mechanotransduction and -sensation, transcriptional regulation, and genome organization. Lamins are the primary scaffold for this nuclear subcompartment, but interactions with lamin-associated peptides in the inner nuclear membrane are self-reinforcing and mutually required. Lamins also interact, directly and indirectly, with peripheral heterochromatin domains called lamina-associated domains (LADs) and help to regulate dynamic 3D genome organization and expression of developmentally regulated genes.
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Affiliation(s)
- Xianrong Wong
- Laboratory of Developmental and Regenerative Biology, Skin Research Institute of Singapore, Agency for Science, Technology and Research (A∗STAR), Singapore 138648
| | - Ashley J Melendez-Perez
- Department of Biological Chemistry and Center for Epigenetics, Johns Hopkins University of Medicine, Baltimore, Maryland 21205, USA
| | - Karen L Reddy
- Department of Biological Chemistry and Center for Epigenetics, Johns Hopkins University of Medicine, Baltimore, Maryland 21205, USA
- Sidney Kimmel Cancer Institute, Johns Hopkins University School of Medicine, Baltimore, Maryland 21231, USA
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15
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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.
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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
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16
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Hurst V, Challa K, Shimada K, Gasser SM. Cytoskeleton integrity influences XRCC1 and PCNA dynamics at DNA damage. Mol Biol Cell 2021; 32:br6. [PMID: 34379448 PMCID: PMC8684753 DOI: 10.1091/mbc.e20-10-0680] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
On induction of DNA damage with 405-nm laser light, proteins involved in base excision repair (BER) are recruited to DNA lesions. We find that the dynamics of factors typical of either short-patch (XRCC1) or long-patch (PCNA) BER are altered by chemicals that perturb actin or tubulin polymerization in human cells. Whereas the destabilization of actin filaments by latrunculin B, cytochalasin B, or Jasplakinolide decreases BER factor accumulation at laser-induced damage, inhibition of tubulin polymerization by nocodazole increases it. We detect no recruitment of actin to sites of laser-induced DNA damage, yet the depolymerization of cytoplasmic actin filaments elevates both actin and tubulin signals in the nucleus. While published evidence suggested a positive role for F-actin in double-strand break repair in mammals, the enrichment of actin in budding yeast nuclei interferes with BER, augmenting sensitivity to Zeocin. Our quantitative imaging results suggest that the depolymerization of cytoplasmic actin may compromise BER efficiency in mammals not only due to elevated levels of nuclear actin but also of tubulin, linking cytoskeletal integrity to BER.
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Affiliation(s)
- Verena Hurst
- Friedrich Miescher Institute for Biomedical Research, Maulbeerstrasse 66, CH-4058 Basel, Switzerland.,Faculty of Natural Sciences, University of Basel, Klingelbergstrasse 90, CH-4056 Basel, Switzerland
| | - Kiran Challa
- Friedrich Miescher Institute for Biomedical Research, Maulbeerstrasse 66, CH-4058 Basel, Switzerland
| | - Kenji Shimada
- Friedrich Miescher Institute for Biomedical Research, Maulbeerstrasse 66, CH-4058 Basel, Switzerland
| | - Susan M Gasser
- Friedrich Miescher Institute for Biomedical Research, Maulbeerstrasse 66, CH-4058 Basel, Switzerland.,Faculty of Natural Sciences, University of Basel, Klingelbergstrasse 90, CH-4056 Basel, Switzerland
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17
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Abstract
Membrane-bound organelles provide physical and functional compartmentalization of biological processes in eukaryotic cells. The characteristic shape and internal organization of these organelles is determined by a combination of multiple internal and external factors. The maintenance of the shape of nucleus, which houses the genetic material within a double membrane bilayer, is crucial for a seamless spatio-temporal control over nuclear and cellular functions. Dynamic morphological changes in the shape of nucleus facilitate various biological processes. Chromatin packaging, nuclear and cytosolic protein organization, and nuclear membrane lipid homeostasis are critical determinants of overall nuclear morphology. As such, a multitude of molecular players and pathways act together to regulate the nuclear shape. Here, we review the known mechanisms governing nuclear shape in various unicellular and multicellular organisms, including the non-spherical nuclei and non-lamin-related structural determinants. The review also touches upon cellular consequences of aberrant nuclear morphologies.
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Affiliation(s)
- Pallavi Deolal
- Department of Biochemistry, School of Life Sciences, University of Hyderabad, Hyderabad, India
| | - Krishnaveni Mishra
- Department of Biochemistry, School of Life Sciences, University of Hyderabad, Hyderabad, India
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18
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You C, Zhang Y, Yang S, Wang X, Yao W, Jin W, Wang W, Hu X, Yang H. Proteomic Analysis of Generative and Vegetative Nuclei Reveals Molecular Characteristics of Pollen Cell Differentiation in Lily. FRONTIERS IN PLANT SCIENCE 2021; 12:641517. [PMID: 34163497 PMCID: PMC8215658 DOI: 10.3389/fpls.2021.641517] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/14/2020] [Accepted: 03/01/2021] [Indexed: 06/13/2023]
Abstract
In plants, the cell fates of a vegetative cell (VC) and generative cell (GC) are determined after the asymmetric division of the haploid microspore. The VC exits the cell cycle and grows a pollen tube, while the GC undergoes further mitosis to produce two sperm cells for double fertilization. However, our understanding of the mechanisms underlying their fate differentiation remains limited. One major advantage of the nuclear proteome analysis is that it is the only method currently able to uncover the systemic differences between VC and GC due to GC being engulfed within the cytoplasm of VC, limiting the use of transcriptome. Here, we obtained pure preparations of the vegetative cell nuclei (VNs) and generative cell nuclei (GNs) from germinating lily pollens. Utilizing these high-purity VNs and GNs, we compared the differential nucleoproteins between them using state-of-the-art quantitative proteomic techniques. We identified 720 different amount proteins (DAPs) and grouped the results in 11 fate differentiation categories. Among them, we identified 29 transcription factors (TFs) and 10 cell fate determinants. Significant differences were found in the molecular activities of vegetative and reproductive nuclei. The TFs in VN mainly participate in pollen tube development. In comparison, the TFs in GN are mainly involved in cell differentiation and male gametogenesis. The identified novel TFs may play an important role in cell fate differentiation. Our data also indicate differences in nuclear pore complexes and epigenetic modifications: more nucleoporins synthesized in VN; more histone variants and chaperones; and structural maintenance of chromosome (SMC) proteins, chromatin remodelers, and DNA methylation-related proteins expressed in GN. The VC has active macromolecular metabolism and mRNA processing, while GC has active nucleic acid metabolism and translation. Moreover, the members of unfolded protein response (UPR) and programmed cell death accumulate in VN, and DNA damage repair is active in GN. Differences in the stress response of DAPs in VN vs. GN were also found. This study provides a further understanding of pollen cell differentiation mechanisms and also a sound basis for future studies of the molecular mechanisms behind cell fate differentiation.
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Affiliation(s)
- Chen You
- State Key Laboratory of Wheat and Maize Crop Science, College of Life Sciences, Henan Agricultural University, Zhengzhou, China
- College of Life Science, Henan Normal University, Xinxiang, China
| | - YuPing Zhang
- State Key Laboratory of Wheat and Maize Crop Science, College of Life Sciences, Henan Agricultural University, Zhengzhou, China
| | - ShaoYu Yang
- State Key Laboratory of Wheat and Maize Crop Science, College of Life Sciences, Henan Agricultural University, Zhengzhou, China
| | - Xu Wang
- State Key Laboratory of Wheat and Maize Crop Science, College of Life Sciences, Henan Agricultural University, Zhengzhou, China
| | - Wen Yao
- State Key Laboratory of Wheat and Maize Crop Science, College of Life Sciences, Henan Agricultural University, Zhengzhou, China
| | - WeiHuan Jin
- State Key Laboratory of Wheat and Maize Crop Science, College of Life Sciences, Henan Agricultural University, Zhengzhou, China
| | - Wei Wang
- State Key Laboratory of Wheat and Maize Crop Science, College of Life Sciences, Henan Agricultural University, Zhengzhou, China
| | - XiuLi Hu
- State Key Laboratory of Wheat and Maize Crop Science, College of Life Sciences, Henan Agricultural University, Zhengzhou, China
| | - Hao Yang
- State Key Laboratory of Wheat and Maize Crop Science, College of Life Sciences, Henan Agricultural University, Zhengzhou, China
- Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing, China
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19
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Ulm P, Jantsch V. Putting organelles in their place. eLife 2021; 10:69422. [PMID: 34018487 PMCID: PMC8139855 DOI: 10.7554/elife.69422] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2021] [Accepted: 05/18/2021] [Indexed: 11/13/2022] Open
Abstract
Experiments in C. elegans reveal new insights into how the ANC-1 protein helps to anchor the nucleus and other organelles in place.
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Affiliation(s)
- Patricia Ulm
- Department of Chromosome Biology, Max Perutz Laboratories, University of Vienna, Vienna Biocenter, Vienna, Austria
| | - Verena Jantsch
- Department of Chromosome Biology, Max Perutz Laboratories, University of Vienna, Vienna Biocenter, Vienna, Austria
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20
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Wong X, Cutler JA, Hoskins VE, Gordon M, Madugundu AK, Pandey A, Reddy KL. Mapping the micro-proteome of the nuclear lamina and lamina-associated domains. Life Sci Alliance 2021; 4:e202000774. [PMID: 33758005 PMCID: PMC8008952 DOI: 10.26508/lsa.202000774] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2020] [Revised: 02/08/2021] [Accepted: 02/09/2021] [Indexed: 01/13/2023] Open
Abstract
The nuclear lamina is a proteinaceous network of filaments that provide both structural and gene regulatory functions by tethering proteins and large domains of DNA, the so-called lamina-associated domains (LADs), to the periphery of the nucleus. LADs are a large fraction of the mammalian genome that are repressed, in part, by their association to the nuclear periphery. The genesis and maintenance of LADs is poorly understood as are the proteins that participate in these functions. In an effort to identify proteins that reside at the nuclear periphery and potentially interact with LADs, we have taken a two-pronged approach. First, we have undertaken an interactome analysis of the inner nuclear membrane bound LAP2β to further characterize the nuclear lamina proteome. To accomplish this, we have leveraged the BioID system, which previously has been successfully used to characterize the nuclear lamina proteome. Second, we have established a system to identify proteins that bind to LADs by developing a chromatin-directed BioID system. We combined the BioID system with the m6A-tracer system which binds to LADs in live cells to identify both LAD proximal and nuclear lamina proteins. In combining these datasets, we have further characterized the protein network at the nuclear lamina, identified putative LAD proximal proteins and found several proteins that appear to interface with both micro-proteomes. Importantly, several proteins essential for LAD function, including heterochromatin regulating proteins related to H3K9 methylation, were identified in this study.
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Affiliation(s)
- Xianrong Wong
- Department of Biological Chemistry, Johns Hopkins University of Medicine, Baltimore, MD, USA
- Center for Epigenetics, Johns Hopkins University School of Medicine, Baltimore, MD, USA
- Laboratory of Developmental and Regenerative Biology, Institute of Medical Biology, Agency for Science, Technology and Research (A∗STAR), Immunos, Singapore
| | - Jevon A Cutler
- Department of Biological Chemistry, Johns Hopkins University of Medicine, Baltimore, MD, USA
- McKusick-Nathans Department of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA
- Center for Epigenetics, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Victoria E Hoskins
- Department of Biological Chemistry, Johns Hopkins University of Medicine, Baltimore, MD, USA
- McKusick-Nathans Department of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA
- Center for Epigenetics, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Molly Gordon
- Department of Cell Biology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Anil K Madugundu
- Department of Biological Chemistry, Johns Hopkins University of Medicine, Baltimore, MD, USA
- McKusick-Nathans Department of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA
- Center for Molecular Medicine, National Institute of Mental Health and Neurosciences (NIMHNS), Bangalore, India
- Institute of Bioinformatics, International Technology Park, Bangalore, India
| | - Akhilesh Pandey
- Department of Biological Chemistry, Johns Hopkins University of Medicine, Baltimore, MD, USA
- McKusick-Nathans Department of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA
- Center for Molecular Medicine, National Institute of Mental Health and Neurosciences (NIMHNS), Bangalore, India
- Institute of Bioinformatics, International Technology Park, Bangalore, India
- Manipal Academy of Higher Education (MAHE), Manipal, India
- Departments of Pathology and Oncology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Karen L Reddy
- Department of Biological Chemistry, Johns Hopkins University of Medicine, Baltimore, MD, USA
- Center for Epigenetics, Johns Hopkins University School of Medicine, Baltimore, MD, USA
- Sidney Kimmel Cancer Institute, Johns Hopkins University School of Medicine, Baltimore, MD, USA
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21
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Manfrevola F, Guillou F, Fasano S, Pierantoni R, Chianese R. LINCking the Nuclear Envelope to Sperm Architecture. Genes (Basel) 2021; 12:genes12050658. [PMID: 33925685 PMCID: PMC8145172 DOI: 10.3390/genes12050658] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2021] [Revised: 04/13/2021] [Accepted: 04/24/2021] [Indexed: 12/11/2022] Open
Abstract
Nuclear architecture undergoes an extensive remodeling during spermatogenesis, especially at levels of spermatocytes (SPC) and spermatids (SPT). Interestingly, typical events of spermiogenesis, such as nuclear elongation, acrosome biogenesis, and flagellum formation, need a functional cooperation between proteins of the nuclear envelope and acroplaxome/manchette structures. In addition, nuclear envelope plays a key role in chromosome distribution. In this scenario, special attention has been focused on the LINC (linker of nucleoskeleton and cytoskeleton) complex, a nuclear envelope-bridge structure involved in the connection of the nucleoskeleton to the cytoskeleton, governing mechanotransduction. It includes two integral proteins: KASH- and SUN-domain proteins, on the outer (ONM) and inner (INM) nuclear membrane, respectively. The LINC complex is involved in several functions fundamental to the correct development of sperm cells such as head formation and head to tail connection, and, therefore, it seems to be important in determining male fertility. This review provides a global overview of the main LINC complex components, with a special attention to their subcellular localization in sperm cells, their roles in the regulation of sperm morphological maturation, and, lastly, LINC complex alterations associated to male infertility.
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Affiliation(s)
- Francesco Manfrevola
- Dipartimento di Medicina Sperimentale, Università degli Studi della Campania L. Vanvitelli, Via Costantinopoli 16, 80138 Napoli, Italy; (F.M.); (S.F.); (R.P.)
| | - Florian Guillou
- PRC, CNRS, IFCE, INRAE, University of Tours, 37380 Nouzilly, France;
| | - Silvia Fasano
- Dipartimento di Medicina Sperimentale, Università degli Studi della Campania L. Vanvitelli, Via Costantinopoli 16, 80138 Napoli, Italy; (F.M.); (S.F.); (R.P.)
| | - Riccardo Pierantoni
- Dipartimento di Medicina Sperimentale, Università degli Studi della Campania L. Vanvitelli, Via Costantinopoli 16, 80138 Napoli, Italy; (F.M.); (S.F.); (R.P.)
| | - Rosanna Chianese
- Dipartimento di Medicina Sperimentale, Università degli Studi della Campania L. Vanvitelli, Via Costantinopoli 16, 80138 Napoli, Italy; (F.M.); (S.F.); (R.P.)
- Correspondence:
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22
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Patil S, Sengupta K. Role of A- and B-type lamins in nuclear structure-function relationships. Biol Cell 2021; 113:295-310. [PMID: 33638183 DOI: 10.1111/boc.202000160] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2020] [Revised: 02/06/2021] [Accepted: 02/08/2021] [Indexed: 12/15/2022]
Abstract
Nuclear lamins are type V intermediate filament proteins that form a filamentous meshwork beneath the inner nuclear membrane. Additionally, a sub-population of A- and B-type lamins localizes in the nuclear interior. The nuclear lamina protects the nucleus from mechanical stress and mediates nucleo-cytoskeletal coupling. Lamins form a scaffold that partially tethers chromatin at the nuclear envelope. The nuclear lamina also stabilises protein-protein interactions involved in gene regulation and DNA repair. The lamin-based protein sub-complexes are implicated in both nuclear and cytoskeletal organisation, the mechanical stability of the nucleus, genome organisation, transcriptional regulation, genome stability and cellular differentiation. Here, we review recent research on nuclear lamins and unique roles of A- and B-type lamins in modulating various nuclear processes and their impact on cell function.
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Affiliation(s)
- Shalaka Patil
- Biology, Chromosome Biology Lab (CBL), Indian Institute of Science Education and Research (IISER), Dr. Homi Bhabha Road, Pune, 411008, India
| | - Kundan Sengupta
- Biology, Chromosome Biology Lab (CBL), Indian Institute of Science Education and Research (IISER), Dr. Homi Bhabha Road, Pune, 411008, India
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23
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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.
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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
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24
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McKenna JF, Gumber HK, Turpin ZM, Jalovec AM, Kartick AC, Graumann K, Bass HW. Maize ( Zea mays L.) Nucleoskeletal Proteins Regulate Nuclear Envelope Remodeling and Function in Stomatal Complex Development and Pollen Viability. FRONTIERS IN PLANT SCIENCE 2021; 12:645218. [PMID: 33679862 PMCID: PMC7925898 DOI: 10.3389/fpls.2021.645218] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/22/2020] [Accepted: 01/27/2021] [Indexed: 05/19/2023]
Abstract
In eukaryotes, the nuclear envelope (NE) encloses chromatin and separates it from the rest of the cell. The Linker of Nucleoskeleton and Cytoskeleton (LINC) complex physically bridges across the NE, linking nuclear and cytoplasmic components. In plants, these LINC complexes are beginning to be ascribed roles in cellular and nuclear functions, including chromatin organization, regulation of nuclei shape and movement, and cell division. Homologs of core LINC components, KASH and SUN proteins, have previously been identified in maize. Here, we characterized the presumed LINC-associated maize nucleoskeletal proteins NCH1 and NCH2, homologous to members of the plant NMCP/CRWN family, and MKAKU41, homologous to AtKAKU4. All three proteins localized to the nuclear periphery when transiently and heterologously expressed as fluorescent protein fusions in Nicotiana benthamiana. Overexpression of MKAKU41 caused dramatic changes in the organization of the nuclear periphery, including nuclear invaginations that stained positive for non-nucleoplasmic markers of the inner and outer NE membranes, and the ER. The severity of these invaginations was altered by changes in LINC connections and the actin cytoskeleton. In maize, MKAKU41 appeared to share genetic functions with other LINC components, including control of nuclei shape, stomatal complex development, and pollen viability. Overall, our data show that NCH1, NCH2, and MKAKU41 have characteristic properties of LINC-associated plant nucleoskeletal proteins, including interactions with NE components suggestive of functions at the nuclear periphery that impact the overall nuclear architecture.
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Affiliation(s)
- Joseph F. McKenna
- School of Life Sciences, University of Warwick, Coventry, United Kingdom
| | - Hardeep K. Gumber
- Department of Biological Science, Florida State University, Tallahassee, FL, United States
| | - Zachary M. Turpin
- Department of Biological Science, Florida State University, Tallahassee, FL, United States
| | - Alexis M. Jalovec
- Department of Biological Science, Florida State University, Tallahassee, FL, United States
| | - Andre C. Kartick
- Department of Biological Science, Florida State University, Tallahassee, FL, United States
| | - Katja Graumann
- Department of Biological and Medical Sciences, Oxford Brookes University, Oxford, United Kingdom
- *Correspondence: Katja Graumann, ; Hank W. Bass,
| | - Hank W. Bass
- Department of Biological Science, Florida State University, Tallahassee, FL, United States
- *Correspondence: Katja Graumann, ; Hank W. Bass,
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25
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Kmonickova V, Frolikova M, Steger K, Komrskova K. The Role of the LINC Complex in Sperm Development and Function. Int J Mol Sci 2020; 21:E9058. [PMID: 33260574 PMCID: PMC7730847 DOI: 10.3390/ijms21239058] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2020] [Revised: 11/24/2020] [Accepted: 11/26/2020] [Indexed: 11/23/2022] Open
Abstract
The LINC (LInker of Nucleoskeleton and Cytoskeleton) complex is localized within the nuclear envelope and consists of SUN (Sad1/UNc84 homology domain-containing) proteins located in the inner nuclear membrane and KASH (Klarsicht/Anc1/Syne1 homology domain-containing) proteins located in the outer nuclear membrane, hence linking nuclear with cytoplasmic structures. While the nucleoplasm-facing side acts as a key player for correct pairing of homolog chromosomes and rapid chromosome movements during meiosis, the cytoplasm-facing side plays a pivotal role for sperm head development and proper acrosome formation during spermiogenesis. A further complex present in spermatozoa is involved in head-to-tail coupling. An intact LINC complex is crucial for the production of fertile sperm, as mutations in genes encoding for complex proteins are known to be associated with male subfertility in both mice and men. The present review provides a comprehensive overview on our current knowledge of LINC complex subtypes present in germ cells and its central role for male reproduction. Future studies on distinct LINC complex components are an absolute requirement to improve the diagnosis of idiopathic male factor infertility and the outcome of assisted reproduction.
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Affiliation(s)
- Vera Kmonickova
- Laboratory of Reproductive Biology, Institute of Biotechnology of the Czech Academy of Sciences, BIOCEV, Prumyslova 595, 252 50 Vestec, Czech Republic; (V.K.); (M.F.)
| | - Michaela Frolikova
- Laboratory of Reproductive Biology, Institute of Biotechnology of the Czech Academy of Sciences, BIOCEV, Prumyslova 595, 252 50 Vestec, Czech Republic; (V.K.); (M.F.)
| | - Klaus Steger
- Department of Urology, Pediatric Urology and Andrology, Molecular Andrology, Justus-Liebig University, 35392 Giessen, Germany;
| | - Katerina Komrskova
- Laboratory of Reproductive Biology, Institute of Biotechnology of the Czech Academy of Sciences, BIOCEV, Prumyslova 595, 252 50 Vestec, Czech Republic; (V.K.); (M.F.)
- Department of Zoology, Faculty of Science, Charles University, Vinicna 7, 128 44 Prague 2, Czech Republic
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26
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Nuclear Envelope Proteins Modulating the Heterochromatin Formation and Functions in Fission Yeast. Cells 2020; 9:cells9081908. [PMID: 32824370 PMCID: PMC7464478 DOI: 10.3390/cells9081908] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2020] [Revised: 08/14/2020] [Accepted: 08/15/2020] [Indexed: 12/16/2022] Open
Abstract
The nuclear envelope (NE) consists of the inner and outer nuclear membranes (INM and ONM), and the nuclear pore complex (NPC), which penetrates the double membrane. ONM continues with the endoplasmic reticulum (ER). INM and NPC can interact with chromatin to regulate the genetic activities of the chromosome. Studies in the fission yeast Schizosaccharomyces pombe have contributed to understanding the molecular mechanisms underlying heterochromatin formation by the RNAi-mediated and histone deacetylase machineries. Recent studies have demonstrated that NE proteins modulate heterochromatin formation and functions through interactions with heterochromatic regions, including the pericentromeric and the sub-telomeric regions. In this review, we first introduce the molecular mechanisms underlying the heterochromatin formation and functions in fission yeast, and then summarize the NE proteins that play a role in anchoring heterochromatic regions and in modulating heterochromatin formation and functions, highlighting roles for a conserved INM protein, Lem2.
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27
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Murata SI, Kuroda M, Kawamura N, Warigaya K, Musangile FY, Matsuzaki I, Kojima F. Microtubule-organizing center-mediated structural atypia in low- and high-grade urothelial carcinoma. Virchows Arch 2020; 478:327-334. [PMID: 32710188 DOI: 10.1007/s00428-020-02895-5] [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: 04/02/2020] [Revised: 06/15/2020] [Accepted: 07/19/2020] [Indexed: 11/25/2022]
Abstract
Urothelial carcinoma (UC) comprises two subtypes, low grade (LG-UC) and high grade (HG-UC), with different pathological and clinical behavior. LG-UC and HG-UC are classified based on cellular and structural atypia of pathological findings. The mechanisms responsible for maintaining structural atypia, such as the disturbance of nuclear polarity, remain unclear. In this study, we studied microtubule-organizing center (MTOC)-mediated nuclear polarity in UC subtypes. We evaluated six cases with normal urothelium (NU), 10 LG-UC cases, and 10 HG-UC cases by double immunofluorescence staining of γ-tubulin as a marker of MTOC and E-cadherin as a marker of each cell border. The number and position of γ-tubulin dots of expression in more than 100 cells per case were assessed using the spatial relationship with the nucleus and surface-basal axis. We found one γ-tubulin dot in most normal and tumor cells, and more than two γ-tubulin dots in 4.6% of NU cells, 6.1% of LG-UC cells, and 9.8% of HG-UC cells. More than three γ-tubulin dots were found only in 1.2% of HG-UC cells. Surface side positioning of γ-tubulin was found in 77.4% of normal urothelial cells, 63.8% of LG-UC cells, and 39.2% of HG-UC cells, whereas aberrant lateral and basal side positioning of γ-tubulin was found in 22.6% of normal urothelial cells, 36.1% of LG-UC cells, and 60.8% of HG-UC cells. We concluded that numerical and positional aberrations of MTOC in UC cases were strongly correlated with both cellular and structural atypia as well as abnormal cell proliferation.
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Affiliation(s)
- Shin-Ichi Murata
- Department of Human Pathology, Wakayama Medical University, 811-1 Kimiidera, Wakayama, 641-8509, Japan.
| | - Masayo Kuroda
- School of Medical Technology, Faculty of Health and Medical Care, Saitama Medical University, Saitama, Japan
| | - Naomi Kawamura
- School of Medical Technology, Faculty of Health and Medical Care, Saitama Medical University, Saitama, Japan
| | - Kenji Warigaya
- Department of Human Pathology, Wakayama Medical University, 811-1 Kimiidera, Wakayama, 641-8509, Japan
| | | | - Ibu Matsuzaki
- Department of Human Pathology, Wakayama Medical University, 811-1 Kimiidera, Wakayama, 641-8509, Japan
| | - Fumiyoshi Kojima
- Department of Human Pathology, Wakayama Medical University, 811-1 Kimiidera, Wakayama, 641-8509, Japan
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28
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Microtubule Organization in Striated Muscle Cells. Cells 2020; 9:cells9061395. [PMID: 32503326 PMCID: PMC7349303 DOI: 10.3390/cells9061395] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Revised: 05/25/2020] [Accepted: 05/28/2020] [Indexed: 12/13/2022] Open
Abstract
Distinctly organized microtubule networks contribute to the function of differentiated cell types such as neurons, epithelial cells, skeletal myotubes, and cardiomyocytes. In striated (i.e., skeletal and cardiac) muscle cells, the nuclear envelope acts as the dominant microtubule-organizing center (MTOC) and the function of the centrosome—the canonical MTOC of mammalian cells—is attenuated, a common feature of differentiated cell types. We summarize the mechanisms known to underlie MTOC formation at the nuclear envelope, discuss the significance of the nuclear envelope MTOC for muscle function and cell cycle progression, and outline potential mechanisms of centrosome attenuation.
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29
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Lawrimore CJ, Lawrimore J, He Y, Chavez S, Bloom K. Polymer perspective of genome mobilization. Mutat Res 2020; 821:111706. [PMID: 32516654 DOI: 10.1016/j.mrfmmm.2020.111706] [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: 02/25/2020] [Revised: 04/30/2020] [Accepted: 05/06/2020] [Indexed: 02/07/2023]
Abstract
Chromosome motion is an intrinsic feature of all DNA-based metabolic processes and is a particularly well-documented response to both DNA damage and repair. By using both biological and polymer physics approaches, many of the contributing factors of chromatin motility have been elucidated. These include the intrinsic properties of chromatin, such as stiffness, as well as the loop modulators condensin and cohesin. Various biological factors such as external tethering to nuclear domains, ATP-dependent processes, and nucleofilaments further impact chromatin motion. DNA damaging agents that induce double-stranded breaks also cause increased chromatin motion that is modulated by recruitment of repair and checkpoint proteins. Approaches that integrate biological experimentation in conjunction with models from polymer physics provide mechanistic insights into the role of chromatin dynamics in biological function. In this review we discuss the polymer models and the effects of both DNA damage and repair on chromatin motion as well as mechanisms that may underlie these effects.
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Affiliation(s)
- Colleen J Lawrimore
- Department of Biology, 623 Fordham Hall CB#3280, University of North Carolina, Chapel Hill, NC 27599-3280, United States
| | - Josh Lawrimore
- Department of Biology, 623 Fordham Hall CB#3280, University of North Carolina, Chapel Hill, NC 27599-3280, United States
| | - Yunyan He
- Department of Biology, 623 Fordham Hall CB#3280, University of North Carolina, Chapel Hill, NC 27599-3280, United States
| | - Sergio Chavez
- Department of Biology, 623 Fordham Hall CB#3280, University of North Carolina, Chapel Hill, NC 27599-3280, United States
| | - Kerry Bloom
- Department of Biology, 623 Fordham Hall CB#3280, University of North Carolina, Chapel Hill, NC 27599-3280, United States.
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30
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Lindenboim L, Zohar H, Worman HJ, Stein R. The nuclear envelope: target and mediator of the apoptotic process. Cell Death Discov 2020; 6:29. [PMID: 32351716 PMCID: PMC7184752 DOI: 10.1038/s41420-020-0256-5] [Citation(s) in RCA: 44] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2020] [Revised: 03/15/2020] [Accepted: 03/19/2020] [Indexed: 02/06/2023] Open
Abstract
Apoptosis is characterized by the destruction of essential cell organelles, including the cell nucleus. The nuclear envelope (NE) separates the nuclear interior from the cytosol. During apoptosis, the apoptotic machinery, in particular caspases, increases NE permeability by cleaving its proteins, such as those of the nuclear pore complex (NPC) and the nuclear lamina. This in turns leads to passive diffusion of cytosolic apoptogenic proteins, such as caspases and nucleases, through NPCs into the nucleus and the subsequent breakdown of the NE and destruction of the nucleus. However, NE leakiness at early stages of the apoptotic process can also occur in a caspase-independent manner, where Bax, by a non-canonical action, promotes transient and repetitive localized generation and subsequent rupture of nuclear protein-filled nuclear bubbles. This NE rupture leads to discharge of apoptogenic nuclear proteins from the nucleus to the cytosol, a process that can contribute to the death process. Therefore, the NE may play a role as mediator of cell death at early stages of apoptosis. The NE can also serve as a platform for assembly of complexes that regulate the death process. Thus, the NE should be viewed as both a mediator of the cell death process and a target.
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Affiliation(s)
- Liora Lindenboim
- Department of Neurobiology, School of Neurobiology, Biochemistry and Biophysics, George S. Wise Faculty of Life Sciences, Tel Aviv University, 69978 Ramat Aviv, Israel
| | - Hila Zohar
- Department of Neurobiology, School of Neurobiology, Biochemistry and Biophysics, George S. Wise Faculty of Life Sciences, Tel Aviv University, 69978 Ramat Aviv, Israel
| | - Howard J. Worman
- Department of Medicine and Department of Pathology and Cell Biology, Vagelos College of Physicians and Surgeons, Columbia University, New York, NY 10032 USA
| | - Reuven Stein
- Department of Neurobiology, School of Neurobiology, Biochemistry and Biophysics, George S. Wise Faculty of Life Sciences, Tel Aviv University, 69978 Ramat Aviv, Israel
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31
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Gumber HK, McKenna JF, Tolmie AF, Jalovec AM, Kartick AC, Graumann K, Bass HW. MLKS2 is an ARM domain and F-actin-associated KASH protein that functions in stomatal complex development and meiotic chromosome segregation. Nucleus 2019; 10:144-166. [PMID: 31221013 PMCID: PMC6649574 DOI: 10.1080/19491034.2019.1629795] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2019] [Revised: 05/13/2019] [Accepted: 05/28/2019] [Indexed: 01/25/2023] Open
Abstract
The linker of nucleoskeleton and cytoskeleton (LINC) complex is an essential multi-protein structure spanning the eukaryotic nuclear envelope. The LINC complex functions to maintain nuclear architecture, positioning, and mobility, along with specialized functions in meiotic prophase and chromosome segregation. Members of the LINC complex were recently identified in maize, an important scientific and agricultural grass species. Here we characterized Maize LINC KASH AtSINE-like2, MLKS2, which encodes a highly conserved SINE-group plant KASH protein with characteristic N-terminal armadillo repeats (ARM). Using a heterologous expression system, we showed that actively expressed GFP-MLKS2 is targeted to the nuclear periphery and colocalizes with F-actin and the endoplasmic reticulum, but not microtubules in the cell cortex. Expression of GFP-MLKS2, but not GFP-MLKS2ΔARM, resulted in nuclear anchoring. Genetic analysis of transposon-insertion mutations, mlks2-1 and mlks2-2, showed that the mutant phenotypes were pleiotropic, affecting root hair nuclear morphology, stomatal complex development, multiple aspects of meiosis, and pollen viability. In male meiosis, the mutants showed defects for bouquet-stage telomere clustering, nuclear repositioning, perinuclear actin accumulation, dispersal of late prophase bivalents, and meiotic chromosome segregation. These findings support a model in which the nucleus is connected to cytoskeletal F-actin through the ARM-domain, predicted alpha solenoid structure of MLKS2. Functional conservation of MLKS2 was demonstrated through genetic rescue of the misshapen nuclear phenotype of an Arabidopsis (triple-WIP) KASH mutant. This study establishes a role for the SINE-type KASH proteins in affecting the dynamic nuclear phenomena required for normal plant growth and fertility. Abbreviations: FRAP: Fluorescence recovery after photobleaching; DPI: Days post infiltration; OD: Optical density; MLKS2: Maize LINC KASH AtSINE-like2; LINC: Linker of nucleoskeleton and cytoskeleton; NE: Nuclear envelope; INM: Inner nuclear membrane; ONM: Outer nuclear membrane.
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Affiliation(s)
- Hardeep K. Gumber
- Department of Biological Science, Florida State University, Tallahassee, FL, USA
| | - Joseph F. McKenna
- Department of Biological and Medical Sciences, Faculty of Health and Life Sciences, Oxford Brookes University, Oxford, UK
| | - Andrea F. Tolmie
- Department of Biological and Medical Sciences, Faculty of Health and Life Sciences, Oxford Brookes University, Oxford, UK
| | - Alexis M. Jalovec
- Department of Biological Science, Florida State University, Tallahassee, FL, USA
| | - Andre C. Kartick
- Department of Biological Science, Florida State University, Tallahassee, FL, USA
| | - Katja Graumann
- Department of Biological and Medical Sciences, Faculty of Health and Life Sciences, Oxford Brookes University, Oxford, UK
| | - Hank W. Bass
- Department of Biological Science, Florida State University, Tallahassee, FL, USA
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32
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Sneider A, Hah J, Wirtz D, Kim DH. Recapitulation of molecular regulators of nuclear motion during cell migration. Cell Adh Migr 2019; 13:50-62. [PMID: 30261154 PMCID: PMC6527386 DOI: 10.1080/19336918.2018.1506654] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2018] [Revised: 07/05/2018] [Accepted: 07/18/2018] [Indexed: 01/12/2023] Open
Abstract
Cell migration is a highly orchestrated cellular event that involves physical interactions of diverse subcellular components. The nucleus as the largest and stiffest organelle in the cell not only maintains genetic functionality, but also actively changes its morphology and translocates through dynamic formation of nucleus-bound contractile stress fibers. Nuclear motion is an active and essential process for successful cell migration and nucleus self-repairs in response to compression and extension forces in complex cell microenvironment. This review recapitulates molecular regulators that are crucial for nuclear motility during cell migration and highlights recent advances in nuclear deformation-mediated rupture and repair processes in a migrating cell.
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Affiliation(s)
- Alexandra Sneider
- Department of Chemical and Biomolecular Engineering, Johns Hopkins University, Baltimore, MD, USA
| | - Jungwon Hah
- KU-KIST Graduate School of Converging Science and Technology, Korea University, Seoul, Republic of Korea
| | - Denis Wirtz
- Department of Chemical and Biomolecular Engineering, Johns Hopkins University, Baltimore, MD, USA
| | - Dong-Hwee Kim
- KU-KIST Graduate School of Converging Science and Technology, Korea University, Seoul, Republic of Korea
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33
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Gill NK, Ly C, Kim PH, Saunders CA, Fong LG, Young SG, Luxton GWG, Rowat AC. DYT1 Dystonia Patient-Derived Fibroblasts Have Increased Deformability and Susceptibility to Damage by Mechanical Forces. Front Cell Dev Biol 2019; 7:103. [PMID: 31294022 PMCID: PMC6606767 DOI: 10.3389/fcell.2019.00103] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2018] [Accepted: 05/27/2019] [Indexed: 12/24/2022] Open
Abstract
DYT1 dystonia is a neurological movement disorder that is caused by a loss-of-function mutation in the DYT1/TOR1A gene, which encodes torsinA, a conserved luminal ATPases-associated with various cellular activities (AAA+) protein. TorsinA is required for the assembly of functional linker of nucleoskeleton and cytoskeleton (LINC) complexes, and consequently the mechanical integration of the nucleus and the cytoskeleton. Despite the potential implications of altered mechanobiology in dystonia pathogenesis, the role of torsinA in regulating cellular mechanical phenotype, or mechanotype, in DYT1 dystonia remains unknown. Here, we define the deformability of mouse fibroblasts lacking functional torsinA as well as human fibroblasts isolated from DYT1 dystonia patients. We find that the deletion of torsinA or the expression of torsinA containing the DYT1 dystonia-causing ΔE302/303 (ΔE) mutation results in more deformable cells. We observe a similar increased deformability of mouse fibroblasts that lack lamina-associated polypeptide 1 (LAP1), which interacts with and stimulates the ATPase activity of torsinA in vitro, as well as with the absence of the LINC complex proteins, Sad1/UNC-84 1 (SUN1) and SUN2, lamin A/C, or lamin B1. Consistent with these findings, we also determine that DYT1 dystonia patient-derived fibroblasts are more compliant than fibroblasts isolated from unafflicted individuals. DYT1 dystonia patient-derived fibroblasts also exhibit increased nuclear strain and decreased viability following mechanical stretch. Taken together, our results establish the foundation for future mechanistic studies of the role of cellular mechanotype and LINC-dependent nuclear-cytoskeletal coupling in regulating cell survival following exposure to mechanical stresses.
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Affiliation(s)
- Navjot Kaur Gill
- Department of Integrative Biology and Physiology, University of California, Los Angeles, Los Angeles, CA, United States
| | - Chau Ly
- Department of Integrative Biology and Physiology, University of California, Los Angeles, Los Angeles, CA, United States.,Department of Bioengineering, University of California, Los Angeles, Los Angeles, CA, United States
| | - Paul H Kim
- Department of Medicine, University of California, Los Angeles, Los Angeles, CA, United States
| | - Cosmo A Saunders
- Department of Genetics, Cell Biology, and Development, University of Minnesota, Minneapolis, MN, United States
| | - Loren G Fong
- Department of Medicine, University of California, Los Angeles, Los Angeles, CA, United States
| | - Stephen G Young
- Department of Medicine, University of California, Los Angeles, Los Angeles, CA, United States.,Department of Human Genetics, University of California, Los Angeles, Los Angeles, CA, United States.,Molecular Biology Institute, University of California, Los Angeles, Los Angeles, CA, United States
| | - G W Gant Luxton
- Department of Genetics, Cell Biology, and Development, University of Minnesota, Minneapolis, MN, United States.,Department of Biomedical Engineering, University of Minnesota, Minneapolis, MN, United States
| | - Amy C Rowat
- Department of Integrative Biology and Physiology, University of California, Los Angeles, Los Angeles, CA, United States
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34
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Abstract
Cellular behavior is continuously affected by microenvironmental forces through the process of mechanotransduction, in which mechanical stimuli are rapidly converted to biochemical responses. Mounting evidence suggests that the nucleus itself is a mechanoresponsive element, reacting to cytoskeletal forces and mediating downstream biochemical responses. The nucleus responds through a host of mechanisms, including partial unfolding, conformational changes, and phosphorylation of nuclear envelope proteins; modulation of nuclear import/export; and altered chromatin organization, resulting in transcriptional changes. It is unclear which of these events present direct mechanotransduction processes and which are downstream of other mechanotransduction pathways. We critically review and discuss the current evidence for nuclear mechanotransduction, particularly in the context of stem cell fate, a largely unexplored topic, and in disease, where an improved understanding of nuclear mechanotransduction is beginning to open new treatment avenues. Finally, we discuss innovative technological developments that will allow outstanding questions in the rapidly growing field of nuclear mechanotransduction to be answered.
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Affiliation(s)
- Melanie Maurer
- Meinig School of Biomedical Engineering and Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, New York 14853, USA; ,
| | - Jan Lammerding
- Meinig School of Biomedical Engineering and Weill Institute for Cell and Molecular Biology, Cornell University, Ithaca, New York 14853, USA; ,
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35
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The nucleus feels the force, LINCed in or not! Curr Opin Cell Biol 2019; 58:114-119. [DOI: 10.1016/j.ceb.2019.02.012] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2018] [Revised: 02/23/2019] [Accepted: 02/28/2019] [Indexed: 12/14/2022]
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36
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Jahed Z, Hao H, Thakkar V, Vu UT, Valdez VA, Rathish A, Tolentino C, Kim SCJ, Fadavi D, Starr DA, Mofrad MRK. Role of KASH domain lengths in the regulation of LINC complexes. Mol Biol Cell 2019; 30:2076-2086. [PMID: 30995155 PMCID: PMC6727767 DOI: 10.1091/mbc.e19-02-0079] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
The linker of the nucleoskeleton and cytoskeleton (LINC) complex is formed by the conserved interactions between Sad-1 and UNC-84 (SUN) and Klarsicht, ANC-1, SYNE homology (KASH) domain proteins, providing a physical coupling between the nucleoskeleton and cytoskeleton that mediates the transfer of physical forces across the nuclear envelope. The LINC complex can perform distinct cellular functions by pairing various KASH domain proteins with the same SUN domain protein. For example, in Caenorhabditis elegans, SUN protein UNC-84 binds to two KASH proteins UNC-83 and ANC-1 to mediate nuclear migration and anchorage, respectively. In addition to distinct cytoplasmic domains, the luminal KASH domain also varies among KASH domain proteins of distinct functions. In this study, we combined in vivo C. elegans genetics and in silico molecular dynamics simulations to understand the relation between the length and amino acid composition of the luminal KASH domain, and the function of the SUN–KASH complex. We show that longer KASH domains can withstand and transfer higher forces and interact with the membrane through a conserved membrane proximal EEDY domain that is unique to longer KASH domains. In agreement with our models, our in vivo results show that swapping the KASH domains of ANC-1 and UNC-83, or shortening the KASH domain of ANC-1, both result in a nuclear anchorage defect in C. elegans.
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Affiliation(s)
- Zeinab Jahed
- Molecular Cell Biomechanics Laboratory, Departments of Bioengineering and Mechanical Engineering, University of California, Berkeley, Berkeley, CA 94720
| | - Hongyan Hao
- Department of Molecular and Cellular Biology, University of California, Davis, Davis, CA 95616
| | - Vyom Thakkar
- Molecular Cell Biomechanics Laboratory, Departments of Bioengineering and Mechanical Engineering, University of California, Berkeley, Berkeley, CA 94720
| | - Uyen T Vu
- Molecular Cell Biomechanics Laboratory, Departments of Bioengineering and Mechanical Engineering, University of California, Berkeley, Berkeley, CA 94720
| | - Venecia A Valdez
- Department of Molecular and Cellular Biology, University of California, Davis, Davis, CA 95616
| | - Akshay Rathish
- Molecular Cell Biomechanics Laboratory, Departments of Bioengineering and Mechanical Engineering, University of California, Berkeley, Berkeley, CA 94720
| | - Chris Tolentino
- Molecular Cell Biomechanics Laboratory, Departments of Bioengineering and Mechanical Engineering, University of California, Berkeley, Berkeley, CA 94720
| | - Samuel C J Kim
- Molecular Cell Biomechanics Laboratory, Departments of Bioengineering and Mechanical Engineering, University of California, Berkeley, Berkeley, CA 94720
| | - Darya Fadavi
- Molecular Cell Biomechanics Laboratory, Departments of Bioengineering and Mechanical Engineering, University of California, Berkeley, Berkeley, CA 94720
| | - Daniel A Starr
- Department of Molecular and Cellular Biology, University of California, Davis, Davis, CA 95616
| | - Mohammad R K Mofrad
- Molecular Cell Biomechanics Laboratory, Departments of Bioengineering and Mechanical Engineering, University of California, Berkeley, Berkeley, CA 94720.,Molecular Biophysics and Integrative Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720
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37
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Jahed Z, Fadavi D, Vu UT, Asgari E, Luxton GWG, Mofrad MRK. Molecular Insights into the Mechanisms of SUN1 Oligomerization in the Nuclear Envelope. Biophys J 2019. [PMID: 29539404 DOI: 10.1016/j.bpj.2018.01.015] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
The LINC complex is found in a wide variety of organisms and is formed by the transluminal interaction between outer- and inner-nuclear-membrane KASH and SUN proteins, respectively. Most extensively studied are SUN1 and SUN2 proteins, which are widely expressed in mammals. Although SUN1 and SUN2 play functionally redundant roles in several cellular processes, more recent studies have revealed diverse and distinct functions for SUN1. While several recent in vitro structural studies have revealed the molecular details of various fragments of SUN2, no such structural information is available for SUN1. Herein, we conduct a systematic analysis of the molecular relationships between SUN1 and SUN2, highlighting key similarities and differences that could lead to clues into their distinct functions. We use a wide range of computational tools, including multiple sequence alignments, homology modeling, molecular docking, and molecular dynamic simulations, to predict structural differences between SUN1 and SUN2, with the goal of understanding the molecular mechanisms underlying SUN1 oligomerization in the nuclear envelope. Our simulations suggest that the structural model of SUN1 is stable in a trimeric state and that SUN1 trimers can associate through their SUN domains to form lateral complexes. We also ask whether SUN1 could adopt an inactive monomeric conformation as seen in SUN2. Our results imply that the KASH binding domain of SUN1 is also inhibited in monomeric SUN1 but through weaker interactions than in monomeric SUN2.
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Affiliation(s)
- Zeinab Jahed
- Molecular Cell Biomechanics Laboratory, Departments of Bioengineering and Mechanical Engineering, University of California, Berkeley, Berkeley, California
| | - Darya Fadavi
- Molecular Cell Biomechanics Laboratory, Departments of Bioengineering and Mechanical Engineering, University of California, Berkeley, Berkeley, California
| | - Uyen T Vu
- Molecular Cell Biomechanics Laboratory, Departments of Bioengineering and Mechanical Engineering, University of California, Berkeley, Berkeley, California
| | - Ehsaneddin Asgari
- Molecular Cell Biomechanics Laboratory, Departments of Bioengineering and Mechanical Engineering, University of California, Berkeley, Berkeley, California
| | - G W Gant Luxton
- Department of Genetics, Cell Biology, and Development, University of Minnesota, Minneapolis, Minnesota
| | - Mohammad R K Mofrad
- Molecular Cell Biomechanics Laboratory, Departments of Bioengineering and Mechanical Engineering, University of California, Berkeley, Berkeley, California; Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, California.
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38
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Gumber HK, McKenna JF, Estrada AL, Tolmie AF, Graumann K, Bass HW. Identification and characterization of genes encoding the nuclear envelope LINC complex in the monocot species Zea mays. J Cell Sci 2019; 132:jcs.221390. [PMID: 30659121 DOI: 10.1242/jcs.221390] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2018] [Accepted: 01/07/2019] [Indexed: 12/18/2022] Open
Abstract
The linker of nucleoskeleton to cytoskeleton (LINC) complex is an essential multi-protein structure spanning the nuclear envelope. It connects the cytoplasm to the nucleoplasm, functions to maintain nuclear shape and architecture and regulates chromosome dynamics during cell division. Knowledge of LINC complex composition and function in the plant kingdom is primarily limited to Arabidopsis, but critically missing from the evolutionarily distant monocots, which include grasses, the most important agronomic crops worldwide. To fill this knowledge gap, we identified and characterized 22 maize genes, including a new grass-specific KASH gene family. By using bioinformatic, biochemical and cell biological approaches, we provide evidence that representative KASH candidates localize to the nuclear periphery and interact with Zea mays (Zm)SUN2 in vivo FRAP experiments using domain deletion constructs verified that this SUN-KASH interaction was dependent on the SUN but not the coiled-coil domain of ZmSUN2. A summary working model is proposed for the entire maize LINC complex encoded by conserved and divergent gene families. These findings expand our knowledge of the plant nuclear envelope in a model grass species, with implications for both basic and applied cellular research.This article has an associated First Person interview with the first author of the paper.
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Affiliation(s)
- Hardeep K Gumber
- Department of Biological Science, Florida State University, Tallahassee, FL 32306-4295, USA
| | - Joseph F McKenna
- Department of Biological and Medical Sciences, Faculty of Health and Life Sciences, Oxford Brookes University, Oxford, OX3 0BP UK
| | - Amado L Estrada
- Department of Biological Science, Florida State University, Tallahassee, FL 32306-4295, USA
| | - Andrea F Tolmie
- Department of Biological and Medical Sciences, Faculty of Health and Life Sciences, Oxford Brookes University, Oxford, OX3 0BP UK
| | - Katja Graumann
- Department of Biological and Medical Sciences, Faculty of Health and Life Sciences, Oxford Brookes University, Oxford, OX3 0BP UK
| | - Hank W Bass
- Department of Biological Science, Florida State University, Tallahassee, FL 32306-4295, USA
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39
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Pereira CD, Serrano JB, Martins F, da Cruz E Silva OAB, Rebelo S. Nuclear envelope dynamics during mammalian spermatogenesis: new insights on male fertility. Biol Rev Camb Philos Soc 2019; 94:1195-1219. [PMID: 30701647 DOI: 10.1111/brv.12498] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2018] [Revised: 01/04/2019] [Accepted: 01/08/2019] [Indexed: 02/06/2023]
Abstract
The production of highly specialized spermatozoa from undifferentiated spermatogonia is a strictly organized and programmed process requiring extensive restructuring of the entire cell. One of the most remarkable cellular transformations accompanying the various phases of spermatogenesis is the profound remodelling of the nuclear architecture, in which the nuclear envelope (NE) seems to be crucially involved. In recent years, several proteins from the distinct layers forming the NE (i.e. the inner and outer nuclear membranes as well as the nuclear lamina) have been associated with meiosis and/or spermiogenesis in different mammalian species. Among these are A- and B-type lamins, Dpy-19-like protein 2 (DPY19L2), lamin B receptor (LBR), lamina-associated polypeptide 1 (LAP1), LAP2/emerin/MAN1 (LEM) domain-containing proteins, spermatogenesis-associated 46 (SPATA46) and diverse elements of the linker of nucleoskeleton and cytoskeleton (LINC) complex, namely Sad-1/UNC-84 homology (SUN) and Klarsicht/ANC-1/Syne-1 homology (KASH) domain-containing proteins. Herein, we summarize the current state of the art on the cellular and subcellular distribution of NE proteins expressed during mammalian spermatogenesis, and discuss the latest research developments regarding their testis-specific functions. This review provides a comprehensive and innovative overview of the NE network as a regulatory platform and as an essential determinant of efficient meiotic chromosome recombination as well as spermiogenesis-associated nuclear remodelling and differentiation in mammalian male germline cells. Thus, this review provides important novel insights on the biological relevance of NE proteins for male fertility.
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Affiliation(s)
- Cátia D Pereira
- Department of Medical Sciences, Neuroscience and Signalling Laboratory, Institute for Biomedicine (iBiMED), University of Aveiro, 3810-193 Aveiro, Portugal
| | - Joana B Serrano
- Department of Medical Sciences, Neuroscience and Signalling Laboratory, Institute for Biomedicine (iBiMED), University of Aveiro, 3810-193 Aveiro, Portugal
| | - Filipa Martins
- Department of Medical Sciences, Neuroscience and Signalling Laboratory, Institute for Biomedicine (iBiMED), University of Aveiro, 3810-193 Aveiro, Portugal
| | - Odete A B da Cruz E Silva
- Department of Medical Sciences, Neuroscience and Signalling Laboratory, Institute for Biomedicine (iBiMED), University of Aveiro, 3810-193 Aveiro, Portugal.,The Discovery CTR, University of Aveiro Campus, 3810-193 Aveiro, Portugal
| | - Sandra Rebelo
- Department of Medical Sciences, Neuroscience and Signalling Laboratory, Institute for Biomedicine (iBiMED), University of Aveiro, 3810-193 Aveiro, Portugal
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Fatema U, Ali MF, Hu Z, Clark AJ, Kawashima T. Gamete Nuclear Migration in Animals and Plants. FRONTIERS IN PLANT SCIENCE 2019; 10:517. [PMID: 31068960 PMCID: PMC6491811 DOI: 10.3389/fpls.2019.00517] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/12/2018] [Accepted: 04/03/2019] [Indexed: 05/04/2023]
Abstract
The migration of male and female gamete nuclei to each other in the fertilized egg is a prerequisite for the blending of genetic materials and the initiation of the next generation. Interestingly, many differences have been found in the mechanism of gamete nuclear movement among animals and plants. Female to male gamete nuclear movement in animals and brown algae relies on microtubules. By contrast, in flowering plants, the male gamete nucleus is carried to the female gamete nucleus by the filamentous actin cytoskeleton. As techniques have developed from light, electron, fluorescence, immunofluorescence, and confocal microscopy to live-cell time-lapse imaging using fluorescently labeled proteins, details of these differences in gamete nuclear migration have emerged in a wide range of eukaryotes. Especially, gamete nuclear migration in flowering plants such as Arabidopsis thaliana, rice, maize, and tobacco has been further investigated, and showed high conservation of the mechanism, yet, with differences among these species. Here, with an emphasis on recent developments in flowering plants, we survey gamete nuclear migration in different eukaryotic groups and highlight the differences and similarities among species.
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Affiliation(s)
- Umma Fatema
- Department of Plant and Soil Sciences, University of Kentucky, Lexington, KY, United States
| | - Mohammad F. Ali
- Department of Plant and Soil Sciences, University of Kentucky, Lexington, KY, United States
| | - Zheng Hu
- Department of Plant and Soil Sciences, University of Kentucky, Lexington, KY, United States
- The Key Lab of Plant Pathology of Hubei Province, Huazhong Agricultural University, Wuhan, China
| | - Anthony J. Clark
- Department of Plant and Soil Sciences, University of Kentucky, Lexington, KY, United States
| | - Tomokazu Kawashima
- Department of Plant and Soil Sciences, University of Kentucky, Lexington, KY, United States
- *Correspondence: Tomokazu Kawashima,
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Cruz-Ramos E, Sandoval-Hernández A, Tecalco-Cruz AC. Differential expression and molecular interactions of chromosome region maintenance 1 and calreticulin exportins in breast cancer cells. J Steroid Biochem Mol Biol 2019; 185:7-16. [PMID: 29981820 DOI: 10.1016/j.jsbmb.2018.07.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/10/2018] [Revised: 06/29/2018] [Accepted: 07/04/2018] [Indexed: 12/20/2022]
Abstract
Chromosome region maintenance 1 (CRM-1) and calreticulin (CALR) are two proteins that act as exportins for some nuclear receptors, in addition to other critical functions for cellular homeostasis. In several cancer types, CRM-1 and CALR are upregulated suggesting an imbalance in their functions. However, the regulation of CRM-1 and CALR, and their biological implications, are not completely known. Here, we evaluated the interplay between the levels of CRM-1 and CALR, and estrogen receptor alpha (ERα) status, in breast cancer cells. CRM-1 and CALR were upregulated in mammary tumors relative to normal mammary tissue. Furthermore, the mRNA and protein levels of CRM-1 and CALR were higher in breast cancer cells lacking ERα, in comparison with those that express ERα. Additionally, both proteins were distributed in the nucleus and cytoplasm in the two cell types. Importantly, we identified novel interactions for these exportins. First, we showed an interaction between CRM-1 and CALR, and then we identified that SUN1 and SUN2, two proteins localized in the nuclear envelop, were able to interact specifically with CRM-1, but not CALR. Interestingly, SUN1 and SUN2 expression seemed to be decreased in breast cancer, thereby affecting the interactions of these proteins with CRM-1, and possibly its actions as an exportin. Thus, our data suggest that expression levels for CRM-1 and CALR, the interaction between these exportins, and specific interactions of SUN1 and SUN2 with CRM-1 but not CALR, may be central elements in nucleo-cytoplasmic transport. Furthermore, deregulation of these elements may have serious implications in the progression of breast and other types of cancer.
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Affiliation(s)
- Eduardo Cruz-Ramos
- Programa de Investigación de Cáncer de Mama, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Apdo Postal, México D.F. 04510, Mexico
| | - Antonio Sandoval-Hernández
- Programa de Investigación de Cáncer de Mama, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Apdo Postal, México D.F. 04510, Mexico
| | - Angeles C Tecalco-Cruz
- Programa de Investigación de Cáncer de Mama, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Apdo Postal, México D.F. 04510, Mexico.
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Jacobson EC, Perry JK, Long DS, Olins AL, Olins DE, Wright BE, Vickers MH, O’Sullivan JM. Migration through a small pore disrupts inactive chromatin organization in neutrophil-like cells. BMC Biol 2018; 16:142. [PMID: 30477489 PMCID: PMC6257957 DOI: 10.1186/s12915-018-0608-2] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2018] [Accepted: 11/02/2018] [Indexed: 01/10/2023] Open
Abstract
BACKGROUND Mammalian cells are flexible and can rapidly change shape when they contract, adhere, or migrate. The nucleus must be stiff enough to withstand cytoskeletal forces, but flexible enough to remodel as the cell changes shape. This is particularly important for cells migrating through confined spaces, where the nuclear shape must change in order to fit through a constriction. This occurs many times in the life cycle of a neutrophil, which must protect its chromatin from damage and disruption associated with migration. Here we characterized the effects of constricted migration in neutrophil-like cells. RESULTS Total RNA sequencing identified that migration of neutrophil-like cells through 5- or 14-μm pores was associated with changes in the transcript levels of inflammation and chemotaxis-related genes when compared to unmigrated cells. Differentially expressed transcripts specific to migration with constriction were enriched for groups of genes associated with cytoskeletal remodeling. Hi-C was used to capture the genome organization in control and migrated cells. Limited switching was observed between the active (A) and inactive (B) compartments after migration. However, global depletion of short-range contacts was observed following migration with constriction compared to migration without constriction. Regions with disrupted contacts, TADs, and compartments were enriched for inactive chromatin. CONCLUSION Short-range genome organization is preferentially altered in inactive chromatin, possibly protecting transcriptionally active contacts from the disruptive effects of migration with constriction. This is consistent with current hypotheses implicating heterochromatin as the mechanoresponsive form of chromatin. Further investigation concerning the contribution of heterochromatin to stiffness, flexibility, and protection of nuclear function will be important for understanding cell migration in relation to human health and disease.
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Affiliation(s)
| | - Jo K. Perry
- Liggins Institute, University of Auckland, Auckland, New Zealand
| | - David S. Long
- Auckland Bioengineering Institute, University of Auckland, Auckland, New Zealand
- Department of Biomedical Engineering, Wichita State University, Wichita, USA
| | - Ada L. Olins
- College of Pharmacy, Department of Pharmaceutical Sciences, University of New England, Portland, ME USA
| | - Donald E. Olins
- College of Pharmacy, Department of Pharmaceutical Sciences, University of New England, Portland, ME USA
| | - Bryon E. Wright
- Auckland Bioengineering Institute, University of Auckland, Auckland, New Zealand
| | - Mark H. Vickers
- Liggins Institute, University of Auckland, Auckland, New Zealand
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Protein oligomerization and mobility within the nuclear envelope evaluated by the time-shifted mean-segmented Q factor. Methods 2018; 157:28-41. [PMID: 30268407 DOI: 10.1016/j.ymeth.2018.09.008] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2018] [Revised: 09/14/2018] [Accepted: 09/25/2018] [Indexed: 11/21/2022] Open
Abstract
Analysis of fluorescence fluctuation experiments by the mean-segmented Q (MSQ) method was recently used to successfully characterize the oligomeric state and mobility of proteins within the nuclear envelope (NE) of living cells. However, two significant shortcomings of MSQ were recognized. Non-ideal detector behavior due to dead-time and afterpulsing as well as the lack of error analysis currently limit the potential of MSQ. This paper presents time-shifted MSQ (tsMSQ), a new formulation of MSQ that is robust with respect to dead-time and afterpulsing. In addition, a protocol for performing error analysis on tsMSQ data is introduced to assess the quality of fit models and estimate the uncertainties of fit parameters. Together, these developments significantly simplify and improve the analysis of fluorescence fluctuation data taken within the NE. To demonstrate these new developments, tsMSQ was used to characterize the oligomeric state and mobility of the luminal domains of two inner nuclear membrane SUN proteins. The results for the luminal domain of SUN2 obtained through tsMSQ without correction for non-ideal detector effects agree with a recent study that was conducted using the original MSQ formulation. Finally, tsMSQ was applied to characterize the oligomeric state and mobility of the luminal domain of the germline-restricted SUN3.
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Sad1 Spatiotemporally Regulates Kinetochore Clustering To Ensure High-Fidelity Chromosome Segregation in the Human Fungal Pathogen Cryptococcus neoformans. mSphere 2018; 3:3/4/e00190-18. [PMID: 29976642 PMCID: PMC6034078 DOI: 10.1128/msphere.00190-18] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
The linker of nucleoskeleton and cytoskeleton (LINC) complex is present in fungi, animals, and plants. It performs diverse functions in animals, and its role(s) have recently been explored in plants. In ascomycetous yeast species, the role of the LINC complex in spindle pole body function and telomere clustering during meiosis has been determined. However, nothing is known about the LINC complex in the fungal phylum of Basidiomycota. In this study, we identified the role of the LINC complex in kinetochore dynamics as well as in nuclear migration in a basidiomycetous yeast, Cryptococcus neoformans, a human pathogen. Unlike most other yeast species, kinetochores remain unclustered during interphase but gradually cluster during mitosis in C. neoformans. We report that the LINC complex is required for timely onset of kinetochore clustering and high-fidelity chromosome segregation in C. neoformans. Thus, our study identifies a novel factor required for kinetochore clustering during mitosis in yeast species. Kinetochore clustering, frequently observed in yeasts, plays a key role in genome organization and chromosome segregation. In the absence of the metaphase plate arrangement, kinetochore clustering in yeast species is believed to facilitate timely kinetochore-microtubule interactions to achieve bivalent attachments of chromosomes during metaphase. The factors determining the dynamics of kinetochore clustering remain largely unknown. We previously reported that kinetochores oscillate between an unclustered and a clustered state during the mitotic cell cycle in the basidiomycetous yeast Cryptococcus neoformans. Based on tubulin localization patterns, while kinetochore clustering appears to be microtubule dependent, an indirect interaction of microtubules with kinetochores is expected in C. neoformans. In this study, we sought to examine possible roles of the SUN-KASH protein complex, known to form a bridge across the nuclear envelope, in regulating kinetochore clustering in C. neoformans. We show that the SUN domain protein Sad1 localizes close to kinetochores in interphase as well as in mitotic cells. Sad1 is nonessential for viability in C. neoformans but is required for proper growth and high-fidelity chromosome segregation. Further, we demonstrate that the onset of kinetochore clustering is significantly delayed in cells lacking Sad1 compared to wild-type cells. Taken together, this study identifies a novel role of the SUN domain protein Sad1 in spatiotemporal regulation of kinetochore clustering during the mitotic cell cycle in C. neoformans. IMPORTANCE The linker of nucleoskeleton and cytoskeleton (LINC) complex is present in fungi, animals, and plants. It performs diverse functions in animals, and its role(s) have recently been explored in plants. In ascomycetous yeast species, the role of the LINC complex in spindle pole body function and telomere clustering during meiosis has been determined. However, nothing is known about the LINC complex in the fungal phylum of Basidiomycota. In this study, we identified the role of the LINC complex in kinetochore dynamics as well as in nuclear migration in a basidiomycetous yeast, Cryptococcus neoformans, a human pathogen. Unlike most other yeast species, kinetochores remain unclustered during interphase but gradually cluster during mitosis in C. neoformans. We report that the LINC complex is required for timely onset of kinetochore clustering and high-fidelity chromosome segregation in C. neoformans. Thus, our study identifies a novel factor required for kinetochore clustering during mitosis in yeast species.
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45
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Kozono T, Tadahira K, Okumura W, Itai N, Tamura-Nakano M, Dohi T, Tonozuka T, Nishikawa A. Jaw1/LRMP has a role in maintaining nuclear shape via interaction with SUN proteins. J Biochem 2018; 164:303-311. [DOI: 10.1093/jb/mvy053] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2018] [Accepted: 05/28/2018] [Indexed: 12/31/2022] Open
Affiliation(s)
- Takuma Kozono
- Department of Food and Energy Systems Science, Graduate School of Bio-Applications Systems Engineering, 3-5-8 Saiwai-cho, Fuchu, Tokyo, Japan
| | - Kazuko Tadahira
- Division of Applied Biological Chemistry, United Graduate School of Agricultural Science, Tokyo University of Agriculture and Technology, 3-5-8 Saiwai-cho, Fuchu, Tokyo, Japan
| | - Wataru Okumura
- Department of Food and Energy Systems Science, Graduate School of Bio-Applications Systems Engineering, 3-5-8 Saiwai-cho, Fuchu, Tokyo, Japan
| | - Nao Itai
- Division of Applied Biological Chemistry, United Graduate School of Agricultural Science, Tokyo University of Agriculture and Technology, 3-5-8 Saiwai-cho, Fuchu, Tokyo, Japan
| | - Miwa Tamura-Nakano
- Communal Laboratory, Research Institute, National Center for Global Health and Medicine, 1-21-1 Toyama, Shinjuku-ku, Tokyo, Japan
| | - Taeko Dohi
- Department of Gastroenterology, Research Center for Hepatitis and Immunology, Research Institute, National Center for Global Health and Medicine, 1-7-1 Kohnodai, Ichikawa, Chiba, Japan
| | - Takashi Tonozuka
- Division of Applied Biological Chemistry, United Graduate School of Agricultural Science, Tokyo University of Agriculture and Technology, 3-5-8 Saiwai-cho, Fuchu, Tokyo, Japan
| | - Atsushi Nishikawa
- Department of Food and Energy Systems Science, Graduate School of Bio-Applications Systems Engineering, 3-5-8 Saiwai-cho, Fuchu, Tokyo, Japan
- Division of Applied Biological Chemistry, United Graduate School of Agricultural Science, Tokyo University of Agriculture and Technology, 3-5-8 Saiwai-cho, Fuchu, Tokyo, Japan
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Tan KL, Haelterman NA, Kwartler CS, Regalado ES, Lee PT, Nagarkar-Jaiswal S, Guo DC, Duraine L, Wangler MF, Bamshad MJ, Nickerson DA, Lin G, Milewicz DM, Bellen HJ. Ari-1 Regulates Myonuclear Organization Together with Parkin and Is Associated with Aortic Aneurysms. Dev Cell 2018; 45:226-244.e8. [PMID: 29689197 PMCID: PMC5920516 DOI: 10.1016/j.devcel.2018.03.020] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2017] [Revised: 02/15/2018] [Accepted: 03/26/2018] [Indexed: 12/25/2022]
Abstract
Nuclei are actively positioned and anchored to the cytoskeleton via the LINC (Linker of Nucleoskeleton and Cytoskeleton) complex. We identified mutations in the Parkin-like E3 ubiquitin ligase Ariadne-1 (Ari-1) that affect the localization and distribution of LINC complex members in Drosophila. ari-1 mutants exhibit nuclear clustering and morphology defects in larval muscles. We show that Ari-1 mono-ubiquitinates the core LINC complex member Koi. Surprisingly, we discovered functional redundancy between Parkin and Ari-1: increasing Parkin expression rescues ari-1 mutant phenotypes and vice versa. We further show that rare variants in the human homolog of ari-1 (ARIH1) are associated with thoracic aortic aneurysms and dissections, conditions resulting from smooth muscle cell (SMC) dysfunction. Human ARIH1 rescues fly ari-1 mutant phenotypes, whereas human variants found in patients fail to do so. In addition, SMCs obtained from patients display aberrant nuclear morphology. Hence, ARIH1 is critical in anchoring myonuclei to the cytoskeleton.
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Affiliation(s)
- Kai Li Tan
- Program in Developmental Biology, Baylor College of Medicine (BCM), Houston, TX 77030, USA
| | - Nele A Haelterman
- Program in Developmental Biology, Baylor College of Medicine (BCM), Houston, TX 77030, USA; Department of Molecular and Human Genetics, BCM, Houston, TX 77030, USA
| | - Callie S Kwartler
- Department of Internal Medicine, The University of Texas Health Science Center at Houston McGovern Medical School, Houston, TX 77030, USA
| | - Ellen S Regalado
- Department of Internal Medicine, The University of Texas Health Science Center at Houston McGovern Medical School, Houston, TX 77030, USA
| | - Pei-Tseng Lee
- Department of Molecular and Human Genetics, BCM, Houston, TX 77030, USA
| | - Sonal Nagarkar-Jaiswal
- Department of Molecular and Human Genetics, BCM, Houston, TX 77030, USA; Howard Hughes Medical Institute, BCM, Houston, TX 77030, USA
| | - Dong-Chuan Guo
- Department of Internal Medicine, The University of Texas Health Science Center at Houston McGovern Medical School, Houston, TX 77030, USA
| | - Lita Duraine
- Howard Hughes Medical Institute, BCM, Houston, TX 77030, USA
| | - Michael F Wangler
- Program in Developmental Biology, Baylor College of Medicine (BCM), Houston, TX 77030, USA; Department of Molecular and Human Genetics, BCM, Houston, TX 77030, USA
| | - Michael J Bamshad
- Department of Genome Sciences, University of Washington, Seattle, WA 98195, USA
| | - Deborah A Nickerson
- Department of Genome Sciences, University of Washington, Seattle, WA 98195, USA
| | - Guang Lin
- Department of Molecular and Human Genetics, BCM, Houston, TX 77030, USA
| | - Dianna M Milewicz
- Department of Internal Medicine, The University of Texas Health Science Center at Houston McGovern Medical School, Houston, TX 77030, USA
| | - Hugo J Bellen
- Program in Developmental Biology, Baylor College of Medicine (BCM), Houston, TX 77030, USA; Department of Molecular and Human Genetics, BCM, Houston, TX 77030, USA; Howard Hughes Medical Institute, BCM, Houston, TX 77030, USA; Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital (TCH), Houston, TX 77030, USA; Department of Neuroscience, BCM, Houston, TX 77030, USA.
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47
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Zeng X, Li K, Yuan R, Gao H, Luo J, Liu F, Wu Y, Wu G, Yan X. Nuclear Envelope-Associated Chromosome Dynamics during Meiotic Prophase I. Front Cell Dev Biol 2018; 5:121. [PMID: 29376050 PMCID: PMC5767173 DOI: 10.3389/fcell.2017.00121] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2017] [Accepted: 12/21/2017] [Indexed: 12/21/2022] Open
Abstract
Chromosome dynamics during meiotic prophase I are associated with a series of major events such as chromosomal reorganization and condensation, pairing/synapsis and recombination of the homologs, and chromosome movements at the nuclear envelope (NE). The NE is the barrier separating the nucleus from the cytoplasm and thus plays a central role in NE-associated chromosomal movements during meiosis. Previous studies have shown in various species that NE-linked chromosome dynamics are actually driven by the cytoskeleton. The linker of nucleoskeleton and cytoskeleton (LINC) complexes are important constituents of the NE that facilitate in the transfer of cytoskeletal forces across the NE to individual chromosomes. The LINCs consist of the inner and outer NE proteins Sad1/UNC-84 (SUN), and Klarsicht/Anc-1/Syne (KASH) domain proteins. Meiosis-specific adaptations of the LINC components and unique modifications of the NE are required during chromosomal movements. Nonetheless, the actual role of the NE in chromosomic dynamic movements in plants remains elusive. This review summarizes the findings of recent studies on meiosis-specific constituents and modifications of the NE and corresponding nucleoplasmic/cytoplasmic adaptors being involved in NE-associated movement of meiotic chromosomes, as well as describes the potential molecular network of transferring cytoplasm-derived forces into meiotic chromosomes in model organisms. It helps to gain a better understanding of the NE-associated meiotic chromosomal movements in plants.
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Affiliation(s)
- Xinhua Zeng
- Oil Crops Research Institute of the Chinese Academy of Agricultural Sciences, Key Laboratory of Biology and Genetic Improvement of Oil Crops, Ministry of Agriculture, Wuhan, China
| | - Keqi Li
- Oil Crops Research Institute of the Chinese Academy of Agricultural Sciences, Key Laboratory of Biology and Genetic Improvement of Oil Crops, Ministry of Agriculture, Wuhan, China
| | - Rong Yuan
- Oil Crops Research Institute of the Chinese Academy of Agricultural Sciences, Key Laboratory of Biology and Genetic Improvement of Oil Crops, Ministry of Agriculture, Wuhan, China
| | - Hongfei Gao
- Oil Crops Research Institute of the Chinese Academy of Agricultural Sciences, Key Laboratory of Biology and Genetic Improvement of Oil Crops, Ministry of Agriculture, Wuhan, China
| | - Junling Luo
- Oil Crops Research Institute of the Chinese Academy of Agricultural Sciences, Key Laboratory of Biology and Genetic Improvement of Oil Crops, Ministry of Agriculture, Wuhan, China
| | - Fang Liu
- Oil Crops Research Institute of the Chinese Academy of Agricultural Sciences, Key Laboratory of Biology and Genetic Improvement of Oil Crops, Ministry of Agriculture, Wuhan, China
| | - Yuhua Wu
- Oil Crops Research Institute of the Chinese Academy of Agricultural Sciences, Key Laboratory of Biology and Genetic Improvement of Oil Crops, Ministry of Agriculture, Wuhan, China
| | - Gang Wu
- Oil Crops Research Institute of the Chinese Academy of Agricultural Sciences, Key Laboratory of Biology and Genetic Improvement of Oil Crops, Ministry of Agriculture, Wuhan, China
| | - Xiaohong Yan
- Oil Crops Research Institute of the Chinese Academy of Agricultural Sciences, Key Laboratory of Biology and Genetic Improvement of Oil Crops, Ministry of Agriculture, Wuhan, China
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Hennen J, Angert I, Hur KH, Gant Luxton GW, Mueller JD. Investigating LINC Complex Protein Homo-oligomerization in the Nuclear Envelopes of Living Cells Using Fluorescence Fluctuation Spectroscopy. Methods Mol Biol 2018; 1840:121-135. [PMID: 30141043 DOI: 10.1007/978-1-4939-8691-0_11] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Linkers of nucleoskeleton and cytoskeleton (LINC) complexes are conserved nuclear envelope (NE) spanning molecular bridges which mechanically integrate the nucleus with the cytoskeleton and mediate force transmission into the nucleoplasm. Despite their critical roles in fundamental cellular processes such as meiotic chromosome and nuclear positioning, the mechanism of LINC complex assembly in cells remains unclear. To begin to address this deficit, we recently developed z-scan fluorescence fluctuation spectroscopy (FFS) and brightness analysis as a method for quantifying the oligomeric states of fluorescent protein-tagged NE proteins including nesprins and SUN proteins. Since the homo-oligomerization of SUN2 is critical for its ability to interact with nesprins within the perinuclear space, the knowledge obtained through quantitative brightness experiments reveals important insights into the in vivo mechanisms of LINC complex assembly. Here we describe the procedure we use to determine the brightness of proteins in the NE of living cells. In addition to the measurement procedure, we discuss the instrumentation requirements and present the results of applying this procedure to measure the brightness of nesprin-2 and SUN2.
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Affiliation(s)
- Jared Hennen
- School of Physics and Astronomy, University of Minnesota, Minneapolis, MN, USA
| | - Isaac Angert
- School of Physics and Astronomy, University of Minnesota, Minneapolis, MN, USA
| | - Kwang-Ho Hur
- School of Physics and Astronomy, University of Minnesota, Minneapolis, MN, USA
| | - G W Gant Luxton
- Department of Genetics, Cell Biology, and Development, University of Minnesota, Minneapolis, MN, USA.
| | - Joachim D Mueller
- School of Physics and Astronomy, University of Minnesota, Minneapolis, MN, USA.
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49
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Parchure A, Munson M, Budnik V. Getting mRNA-Containing Ribonucleoprotein Granules Out of a Nuclear Back Door. Neuron 2017; 96:604-615. [PMID: 29096075 DOI: 10.1016/j.neuron.2017.10.020] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2017] [Revised: 10/15/2017] [Accepted: 10/16/2017] [Indexed: 12/21/2022]
Abstract
A pivotal feature of long-lasting synaptic plasticity is the localization of RNAs and the protein synthesis machinery at synaptic sites. How and where ribonucleoprotein (RNP) transport granules that support this synthetic activity are formed is of fundamental importance. The prevailing model poses that the nuclear pore complex (NPC) is the sole gatekeeper for transit of cellular material in and out of the nucleus. However, insights from the nuclear assembly of large viral capsids highlight a back door route for nuclear escape, a process referred to nuclear envelope (NE) budding. Recent studies indicate that NE budding might be an endogenous cellular process for the nuclear export of very large RNPs and protein aggregates. In Drosophila, this mechanism is required for synaptic plasticity, but its role may extend beyond the nervous system, in tissues where local changes in translation are required. Here we discuss these recent findings and a potential relationship between NE budding and the NPC.
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Affiliation(s)
- Anup Parchure
- Department of Neurobiology, University of Massachusetts Medical School, Worcester, MA, USA
| | - Mary Munson
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, MA, USA
| | - Vivian Budnik
- Department of Neurobiology, University of Massachusetts Medical School, Worcester, MA, USA.
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50
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Guénolé A, Legube G. A meeting at risk: Unrepaired DSBs go for broke. Nucleus 2017; 8:589-599. [PMID: 29099269 PMCID: PMC5788565 DOI: 10.1080/19491034.2017.1380138] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2017] [Revised: 09/06/2017] [Accepted: 09/12/2017] [Indexed: 12/17/2022] Open
Abstract
Translocations are dramatic genomic rearrangements due to aberrant rejoining of distant DNA ends that can trigger cancer onset and progression. Translocations frequently occur in genes, yet the mechanisms underlying their formation remain poorly understood. One potential mechanism involves DNA Double Strand Break mobility and juxtaposition (i.e. clustering), an event that has been intensively debated over the past decade. Using Capture Hi-C, we recently found that DSBs do in fact cluster in human nuclei but only when induced in transcriptionally active genes. Notably, we found that clustering of damaged genes is regulated by cell cycle progression and coincides with damage persistency. Here, we discuss the mechanisms that could sustain clustering and speculate on the functional consequences of this seemingly double edge sword mechanism that may well stand at the heart of translocation biogenesis.
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Affiliation(s)
- Aude Guénolé
- LBCMCP, Centre de Biologie Intégrative (CBI), CNRS, Université de Toulouse, UT3, Toulouse, France
| | - Gaëlle Legube
- LBCMCP, Centre de Biologie Intégrative (CBI), CNRS, Université de Toulouse, UT3, Toulouse, France
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