51
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Isolated nuclei stiffen in response to low intensity vibration. J Biomech 2020; 111:110012. [PMID: 32932075 DOI: 10.1016/j.jbiomech.2020.110012] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2020] [Revised: 08/20/2020] [Accepted: 08/21/2020] [Indexed: 02/03/2023]
Abstract
The nucleus, central to all cellular activity, relies on both direct mechanical input and its molecular transducers to sense and respond to external stimuli. While it has been shown that isolated nuclei can adapt to applied force ex vivo, the mechanisms governing nuclear mechanoadaptation in response to physiologic forces in vivo remain unclear. To investigate nuclear mechanoadaptation in cells, we developed an atomic force microscopy (AFM) based procedure to probe live nuclei isolated from mesenchymal stem cells (MSCs) following the application of low intensity vibration (LIV) to determine whether nuclear stiffness increases as a result of LIV. Results indicated that isolated nuclei were, on average, 30% softer than nuclei tested within intact MSCs prior to LIV. When the nucleus was isolated following LIV (0.7 g, 90 Hz, 20 min) applied four times (4×) separated by 1 h intervals, stiffness of isolated nuclei increased 75% compared to non-LIV controls. LIV-induced nuclear stiffening required functional Linker of Nucleoskeleton and Cytoskeleton (LINC) complex, but was not accompanied by increased levels of the nuclear envelope proteins LaminA/C or Sun-2. While depleting LaminA/C or Sun-1&2 resulted in either a 47% or 39% increased heterochromatin to nuclear area ratio in isolated nuclei, the heterochromatin to nuclear area ratio was decreased by 25% in LIV-treated nuclei compared to controls, indicating LIV-induced changes in the heterochromatin structure. Overall, our findings indicate that increased apparent cell stiffness in response to exogenous mechanical challenge of MSCs in the form of LIV is in part retained by increased nuclear stiffness and changes in heterochromatin structure.
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Corbeil D, Santos MF, Karbanová J, Kurth T, Rappa G, Lorico A. Uptake and Fate of Extracellular Membrane Vesicles: Nucleoplasmic Reticulum-Associated Late Endosomes as a New Gate to Intercellular Communication. Cells 2020; 9:cells9091931. [PMID: 32825578 PMCID: PMC7563309 DOI: 10.3390/cells9091931] [Citation(s) in RCA: 57] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Revised: 08/18/2020] [Accepted: 08/20/2020] [Indexed: 02/06/2023] Open
Abstract
Extracellular membrane vesicles (EVs) are emerging as new vehicles in intercellular communication, but how the biological information contained in EVs is shared between cells remains elusive. Several mechanisms have been described to explain their release from donor cells and the initial step of their uptake by recipient cells, which triggers a cellular response. Yet, the intracellular routes and subcellular fate of EV content upon internalization remain poorly characterized. This is particularly true for EV-associated proteins and nucleic acids that shuttle to the nucleus of host cells. In this review, we will describe and discuss the release of EVs from donor cells, their uptake by recipient cells, and the fate of their cargoes, focusing on a novel intracellular route wherein small GTPase Rab7+ late endosomes containing endocytosed EVs enter into nuclear envelope invaginations and deliver their cargo components to the nucleoplasm of recipient cells. A tripartite protein complex composed of (VAMP)-associated protein A (VAP-A), oxysterol-binding protein (OSBP)-related protein-3 (ORP3), and Rab7 is essential for the transfer of EV-derived components to the nuclear compartment by orchestrating the particular localization of late endosomes in the nucleoplasmic reticulum.
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Affiliation(s)
- Denis Corbeil
- Biotechnology Center (BIOTEC) and Center for Molecular and Cellular Bioengineering (CMCB), Technische Universität Dresden, Tatzberg 47-49, 01307 Dresden, Germany; (J.K.)
- Correspondence: (D.C.); (A.L.); Tel.: +49-(0)351-463-40118 (D.C.); +1-(702)-777-3942 (A.L.); Fax: +49-(0)351-463-40244 (D.C.); +1-(702)-777-1758 (A.L.)
| | - Mark F. Santos
- College of Osteopathic Medicine, Touro University Nevada, 874 American Pacific Drive, Henderson, NV 89014, USA; (M.F.S.); (G.R.)
| | - Jana Karbanová
- Biotechnology Center (BIOTEC) and Center for Molecular and Cellular Bioengineering (CMCB), Technische Universität Dresden, Tatzberg 47-49, 01307 Dresden, Germany; (J.K.)
| | - Thomas Kurth
- Center for Regenerative Therapies Dresden and CMCB, Technische Universität Dresden, Fetscherstraße 105, 01307 Dresden, Germany; (T.K.)
| | - Germana Rappa
- College of Osteopathic Medicine, Touro University Nevada, 874 American Pacific Drive, Henderson, NV 89014, USA; (M.F.S.); (G.R.)
| | - Aurelio Lorico
- College of Osteopathic Medicine, Touro University Nevada, 874 American Pacific Drive, Henderson, NV 89014, USA; (M.F.S.); (G.R.)
- Mediterranean Institute of Oncology, Via Penninazzo, 11, 95029 Viagrande, Italy
- Correspondence: (D.C.); (A.L.); Tel.: +49-(0)351-463-40118 (D.C.); +1-(702)-777-3942 (A.L.); Fax: +49-(0)351-463-40244 (D.C.); +1-(702)-777-1758 (A.L.)
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53
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Nuclear mechanosensing: mechanism and consequences of a nuclear rupture. Mutat Res 2020; 821:111717. [PMID: 32810711 DOI: 10.1016/j.mrfmmm.2020.111717] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2020] [Revised: 06/25/2020] [Accepted: 07/14/2020] [Indexed: 12/22/2022]
Abstract
The physical connections between the cytoskeletal system and the nucleus provide a route for the nucleus to sense the mechanical stress both inside and outside of the cell. Failure to withstand such stress leads to nuclear rupture, which is observed in human diseases. In this review, we will go through the recent findings and our current understandings of nuclear rupture. Starting with the triggers of nuclear rupture, including the aberrant nuclear lamina composition and the elevated actomyosin contractility. We will also discuss the role of ESCRT-III in nuclear rupture repair and the biological consequences of nuclear rupture, including the negative impacts on cellular compartmentalization, DNA damage, and cellular differentiation. Recent studies on nuclear rupture provide further insights into the direct mechanistic link between nuclear rupture and several pathological conditions. Such knowledge can guide us in developing potential therapeutic solutions for the patients.
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Yang F, Zhang Y, Zhu J, Wang J, Jiang Z, Zhao C, Yang Q, Huang Y, Yao W, Pang W, Han L, Zhou J. Laminar Flow Protects Vascular Endothelial Tight Junctions and Barrier Function via Maintaining the Expression of Long Non-coding RNA MALAT1. Front Bioeng Biotechnol 2020; 8:647. [PMID: 32671044 PMCID: PMC7330101 DOI: 10.3389/fbioe.2020.00647] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2020] [Accepted: 05/27/2020] [Indexed: 01/05/2023] Open
Abstract
Atherosclerotic plaque preferentially develops in arterial curvatures and branching regions, where endothelial cells constantly experience disturbed blood flow. By contrast, the straight arteries are generally protected from plaque formation due to exposure of endothelial cells to vaso-protective laminar blood flow. However, the role of flow patterns on endothelial barrier function remains largely unclear. This study aimed to investigate new mechanisms underlying the blood flow pattern-regulated endothelial integrity. Exposure of human endothelial cells to pulsatile shear (PS, mimicking the laminar flow) compared to oscillatory shear (OS, mimicking the disturbed flow) increased the expressions of long non-coding RNA MALAT1 and tight junction proteins ZO1 and Occludin. This increase was abolished by knocking down MALAT1 or Nesprin1 and 2. PS promoted the association between Nesprin1 and SUN2 at the nuclear envelopes, and induced a nuclear translocation of β-catenin, likely through enhancing the interaction between β-catenin and Nesprin1. In the in vivo study, mice were treated via intraperitoneal injection with β-catenin agonist SKL2001 or its inhibitor XAV939, and they were then subjected to Evans blue injection to assess aortic endothelial permeability. The aortas exhibited a reduced wall permeability to Evans blue in SKL2001-treated mice whereas an enhanced permeability in XAV939-treated mice. We concluded that laminar flow promotes nuclear localization of Nesprins, which facilitates the nuclear access of β-catenin to stimulate MALAT1 transcription, resulting in increased expressions of ZO1 and Occludin to protect endothelial barrier function.
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Affiliation(s)
- Fangfang Yang
- Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Peking University, Beijing, China.,Key Laboratory of Molecular Cardiovascular Science, Ministry of Education, Beijing, China.,NHC Key Laboratory of Cardiovascular Molecular Biology and Regulatory Peptides, Beijing, China
| | - Yunpeng Zhang
- Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Peking University, Beijing, China.,Key Laboratory of Molecular Cardiovascular Science, Ministry of Education, Beijing, China.,NHC Key Laboratory of Cardiovascular Molecular Biology and Regulatory Peptides, Beijing, China
| | - Juanjuan Zhu
- Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Peking University, Beijing, China.,Key Laboratory of Molecular Cardiovascular Science, Ministry of Education, Beijing, China.,NHC Key Laboratory of Cardiovascular Molecular Biology and Regulatory Peptides, Beijing, China
| | - Jin Wang
- Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Peking University, Beijing, China.,Key Laboratory of Molecular Cardiovascular Science, Ministry of Education, Beijing, China.,NHC Key Laboratory of Cardiovascular Molecular Biology and Regulatory Peptides, Beijing, China
| | - Zhitong Jiang
- Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Peking University, Beijing, China.,Key Laboratory of Molecular Cardiovascular Science, Ministry of Education, Beijing, China.,NHC Key Laboratory of Cardiovascular Molecular Biology and Regulatory Peptides, Beijing, China
| | - Chuanrong Zhao
- Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Peking University, Beijing, China.,Key Laboratory of Molecular Cardiovascular Science, Ministry of Education, Beijing, China.,NHC Key Laboratory of Cardiovascular Molecular Biology and Regulatory Peptides, Beijing, China
| | - Qianru Yang
- Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Peking University, Beijing, China.,Key Laboratory of Molecular Cardiovascular Science, Ministry of Education, Beijing, China.,NHC Key Laboratory of Cardiovascular Molecular Biology and Regulatory Peptides, Beijing, China
| | - Yu Huang
- Shenzhen Research Institute, Institute of Vascular Medicine and Li Ka Shing Institute of Health Sciences, Chinese University of Hong Kong, Hong Kong, China
| | - Weijuan Yao
- Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Peking University, Beijing, China.,Key Laboratory of Molecular Cardiovascular Science, Ministry of Education, Beijing, China.,NHC Key Laboratory of Cardiovascular Molecular Biology and Regulatory Peptides, Beijing, China
| | - Wei Pang
- Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Peking University, Beijing, China.,Key Laboratory of Molecular Cardiovascular Science, Ministry of Education, Beijing, China.,NHC Key Laboratory of Cardiovascular Molecular Biology and Regulatory Peptides, Beijing, China
| | - Lili Han
- Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Peking University, Beijing, China.,Key Laboratory of Molecular Cardiovascular Science, Ministry of Education, Beijing, China.,NHC Key Laboratory of Cardiovascular Molecular Biology and Regulatory Peptides, Beijing, China
| | - Jing Zhou
- Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Peking University, Beijing, China.,Key Laboratory of Molecular Cardiovascular Science, Ministry of Education, Beijing, China.,NHC Key Laboratory of Cardiovascular Molecular Biology and Regulatory Peptides, Beijing, China
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55
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Muscle cell differentiation and development pathway defects in Emery-Dreifuss muscular dystrophy. Neuromuscul Disord 2020; 30:443-456. [DOI: 10.1016/j.nmd.2020.04.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2019] [Revised: 03/20/2020] [Accepted: 04/15/2020] [Indexed: 12/12/2022]
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56
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Abstract
LINC complexes (Linker of Nucleoskeleton and Cytoskeleton), consisting of inner nuclear membrane SUN (Sad1, UNC-84) proteins and outer nuclear membrane KASH (Klarsicht, ANC-1, and Syne Homology) proteins, are essential for nuclear positioning, cell migration and chromosome dynamics. To test the in vivo functions of conserved interfaces revealed by crystal structures, Cain et al used a combination of Caenorhabditis elegans genetics, imaging in cultured NIH 3T3 fibroblasts, and Molecular Dynamic simulations, to study SUN-KASH interactions. Conserved aromatic residues at the -7 position of the C-termini of KASH proteins and conserved disulfide bonds in LINC complexes play important roles in force transmission across the nuclear envelope. Other properties of LINC complexes, such as the helices preceding the SUN domain, the longer coiled-coils spanning the perinuclear space and higher-order organization may also function to transmit mechanical forces generated by the cytoskeleton across the nuclear envelope.
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Affiliation(s)
- Hongyan Hao
- a Department of Molecular and Cellular Biology , University of California , Davis , CA USA
| | - Daniel A Starr
- a Department of Molecular and Cellular Biology , University of California , Davis , CA USA
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57
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In Vitro Cytotoxicity Effects of Zinc Oxide Nanoparticles on Spermatogonia Cells. Cells 2020; 9:cells9051081. [PMID: 32357578 PMCID: PMC7290761 DOI: 10.3390/cells9051081] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2020] [Revised: 04/23/2020] [Accepted: 04/24/2020] [Indexed: 12/12/2022] Open
Abstract
Zinc Oxide Nanoparticles (ZnO NPs) are a type of metal oxide nanoparticle with an extensive use in biomedicine. Several studies have focused on the biosafety of ZnO NPs, since their size and surface area favor entrance and accumulation in the body, which can induce toxic effects. In previous studies, ZnO NPs have been identified as a dose- and time-dependent cytotoxic inducer in testis and male germ cells. However, the consequences for the first cell stage of spermatogenesis, spermatogonia, have never been evaluated. Therefore, the aim of the present work is to evaluate in vitro the cytotoxic effects of ZnO NPs in spermatogonia cells, focusing on changes in cytoskeleton and nucleoskeleton. For that purpose, GC-1 cell line derived from mouse testes was selected as a model of spermatogenesis. These cells were treated with different doses of ZnO NPs for 6 h and 12 h. The impact of GC-1 cells exposure to ZnO NPs on cell viability, cell damage, and cytoskeleton and nucleoskeleton dynamics was assessed. Our results clearly indicate that higher concentrations of ZnO NPs have a cytotoxic effect in GC-1 cells, leading to an increase of intracellular Reactive Oxygen Species (ROS) levels, DNA damage, cytoskeleton and nucleoskeleton dynamics alterations, and consequently cell death. In conclusion, it is here reported for the first time that ZnO NPs induce cytotoxic effects, including changes in cytoskeleton and nucleoskeleton in mouse spermatogonia cells, which may compromise the progression of spermatogenesis in a time- and dose-dependent manner.
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58
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Maldonado RJK, Rice B, Chen EC, Tuffy KM, Chiari EF, Fahrbach KM, Hope TJ, Parent LJ. Visualizing Association of the Retroviral Gag Protein with Unspliced Viral RNA in the Nucleus. mBio 2020; 11:e00524-20. [PMID: 32265329 PMCID: PMC7157774 DOI: 10.1128/mbio.00524-20] [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: 03/07/2020] [Accepted: 03/12/2020] [Indexed: 11/20/2022] Open
Abstract
Packaging of genomic RNA (gRNA) by retroviruses is essential for infectivity, yet the subcellular site of the initial interaction between the Gag polyprotein and gRNA remains poorly defined. Because retroviral particles are released from the plasma membrane, it was previously thought that Gag proteins initially bound to gRNA in the cytoplasm or at the plasma membrane. However, the Gag protein of the avian retrovirus Rous sarcoma virus (RSV) undergoes active nuclear trafficking, which is required for efficient gRNA encapsidation (L. Z. Scheifele, R. A. Garbitt, J. D. Rhoads, and L. J. Parent, Proc Natl Acad Sci U S A 99:3944-3949, 2002, https://doi.org/10.1073/pnas.062652199; R. Garbitt-Hirst, S. P. Kenney, and L. J. Parent, J Virol 83:6790-6797, 2009, https://doi.org/10.1128/JVI.00101-09). These results raise the intriguing possibility that the primary contact between Gag and gRNA might occur in the nucleus. To examine this possibility, we created a RSV proviral construct that includes 24 tandem repeats of MS2 RNA stem-loops, making it possible to track RSV viral RNA (vRNA) in live cells in which a fluorophore-conjugated MS2 coat protein is coexpressed. Using confocal microscopy, we observed that both wild-type Gag and a nuclear export mutant (Gag.L219A) colocalized with vRNA in the nucleus. In live-cell time-lapse images, the wild-type Gag protein trafficked together with vRNA as a single ribonucleoprotein (RNP) complex in the nucleoplasm near the nuclear periphery, appearing to traverse the nuclear envelope into the cytoplasm. Furthermore, biophysical imaging methods suggest that Gag and the unspliced vRNA physically interact in the nucleus. Taken together, these data suggest that RSV Gag binds unspliced vRNA to export it from the nucleus, possibly for packaging into virions as the viral genome.IMPORTANCE Retroviruses cause severe diseases in animals and humans, including cancer and acquired immunodeficiency syndromes. To propagate infection, retroviruses assemble new virus particles that contain viral proteins and unspliced vRNA to use as gRNA. Despite the critical requirement for gRNA packaging, the molecular mechanisms governing the identification and selection of gRNA by the Gag protein remain poorly understood. In this report, we demonstrate that the Rous sarcoma virus (RSV) Gag protein colocalizes with unspliced vRNA in the nucleus in the interchromatin space. Using live-cell confocal imaging, RSV Gag and unspliced vRNA were observed to move together from inside the nucleus across the nuclear envelope, suggesting that the Gag-gRNA complex initially forms in the nucleus and undergoes nuclear export into the cytoplasm as a viral ribonucleoprotein (vRNP) complex.
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Affiliation(s)
| | - Breanna Rice
- Department of Medicine, Penn State College of Medicine, Hershey, Pennsylvania, USA
| | - Eunice C Chen
- Department of Medicine, Penn State College of Medicine, Hershey, Pennsylvania, USA
| | - Kevin M Tuffy
- Department of Medicine, Penn State College of Medicine, Hershey, Pennsylvania, USA
| | - Estelle F Chiari
- Department of Medicine, Penn State College of Medicine, Hershey, Pennsylvania, USA
| | - Kelly M Fahrbach
- Department of Cell and Molecular Biology, Northwestern University, Chicago, Illinois, USA
| | - Thomas J Hope
- Department of Cell and Molecular Biology, Northwestern University, Chicago, Illinois, USA
| | - Leslie J Parent
- Department of Medicine, Penn State College of Medicine, Hershey, Pennsylvania, USA
- Department of Microbiology and Immunology, Penn State College of Medicine, Hershey, Pennsylvania, USA
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59
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Nakazawa N, Kengaku M. Mechanical Regulation of Nuclear Translocation in Migratory Neurons. Front Cell Dev Biol 2020; 8:150. [PMID: 32226788 PMCID: PMC7080992 DOI: 10.3389/fcell.2020.00150] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2019] [Accepted: 02/24/2020] [Indexed: 12/14/2022] Open
Abstract
Neuronal migration is a critical step during the formation of functional neural circuits in the brain. Newborn neurons need to move across long distances from the germinal zone to their individual sites of function; during their migration, they must often squeeze their large, stiff nuclei, against strong mechanical stresses, through narrow spaces in developing brain tissue. Recent studies have clarified how actomyosin and microtubule motors generate mechanical forces in specific subcellular compartments and synergistically drive nuclear translocation in neurons. On the other hand, the mechanical properties of the surrounding tissues also contribute to their function as an adhesive support for cytoskeletal force transmission, while they also serve as a physical barrier to nuclear translocation. In this review, we discuss recent studies on nuclear migration in developing neurons, from both cell and mechanobiological viewpoints.
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Affiliation(s)
- Naotaka Nakazawa
- Institute for Integrated Cell-Material Sciences (WPI-iCeMS), Kyoto University Institute for Advanced Study, Kyoto University, Kyoto, Japan
| | - Mineko Kengaku
- Institute for Integrated Cell-Material Sciences (WPI-iCeMS), Kyoto University Institute for Advanced Study, Kyoto University, Kyoto, Japan.,Graduate School of Biostudies, Kyoto University, Kyoto, Japan
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60
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Gao Q, Khan R, Yu C, Alsheimer M, Jiang X, Ma H, Shi Q. The testis-specific LINC component SUN3 is essential for sperm head shaping during mouse spermiogenesis. J Biol Chem 2020; 295:6289-6298. [PMID: 32156700 DOI: 10.1074/jbc.ra119.012375] [Citation(s) in RCA: 45] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2019] [Revised: 03/06/2020] [Indexed: 01/16/2023] Open
Abstract
Sperm head shaping is a key event in spermiogenesis and is tightly controlled via the acrosome-manchette network. Linker of nucleoskeleton and cytoskeleton (LINC) complexes consist of Sad1 and UNC84 domain-containing (SUN) and Klarsicht/ANC-1/Syne-1 homology (KASH) domain proteins and form conserved nuclear envelope bridges implicated in transducing mechanical forces from the manchette to sculpt sperm nuclei into a hook-like shape. However, the role of LINC complexes in sperm head shaping is still poorly understood. Here we assessed the role of SUN3, a testis-specific LINC component harboring a conserved SUN domain, in spermiogenesis. We show that CRISPR/Cas9-generated Sun3 knockout male mice are infertile, displaying drastically reduced sperm counts and a globozoospermia-like phenotype, including a missing, mislocalized, or fragmented acrosome, as well as multiple defects in sperm flagella. Further examination revealed that the sperm head abnormalities are apparent at step 9 and that the sperm nuclei fail to elongate because of the absence of manchette microtubules and perinuclear rings. These observations indicate that Sun3 deletion likely impairs the ability of the LINC complex to transduce the cytoskeletal force to the nuclear envelope, required for sperm head elongation. We also found that SUN3 interacts with SUN4 in mouse testes and that the level of SUN4 proteins is drastically reduced in Sun3-null mice. Altogether, our results indicate that SUN3 is essential for sperm head shaping and male fertility, providing molecular clues regarding the underlying pathology of the globozoospermia-like phenotype.
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Affiliation(s)
- Qian Gao
- First Affiliated Hospital of the University of Science and Technology of China, Hefei National Laboratory for Physical Sciences at Microscale, Chinese Academy of Sciences Key Laboratory of Innate Immunity and Chronic Diseases, School of Life Sciences, Chinese Academy of Sciences Center for Excellence in Molecular Cell Science, Collaborative Innovation Center of Genetics and Development, University of Science and Technology of China, Hefei 230027, China
| | - Ranjha Khan
- First Affiliated Hospital of the University of Science and Technology of China, Hefei National Laboratory for Physical Sciences at Microscale, Chinese Academy of Sciences Key Laboratory of Innate Immunity and Chronic Diseases, School of Life Sciences, Chinese Academy of Sciences Center for Excellence in Molecular Cell Science, Collaborative Innovation Center of Genetics and Development, University of Science and Technology of China, Hefei 230027, China
| | - Changping Yu
- First Affiliated Hospital of the University of Science and Technology of China, Hefei National Laboratory for Physical Sciences at Microscale, Chinese Academy of Sciences Key Laboratory of Innate Immunity and Chronic Diseases, School of Life Sciences, Chinese Academy of Sciences Center for Excellence in Molecular Cell Science, Collaborative Innovation Center of Genetics and Development, University of Science and Technology of China, Hefei 230027, China
| | - Manfred Alsheimer
- Department of Cell and Developmental Biology, Biocenter, University of Würzburg, 97074 Würzburg, Germany
| | - Xiaohua Jiang
- First Affiliated Hospital of the University of Science and Technology of China, Hefei National Laboratory for Physical Sciences at Microscale, Chinese Academy of Sciences Key Laboratory of Innate Immunity and Chronic Diseases, School of Life Sciences, Chinese Academy of Sciences Center for Excellence in Molecular Cell Science, Collaborative Innovation Center of Genetics and Development, University of Science and Technology of China, Hefei 230027, China
| | - Hui Ma
- First Affiliated Hospital of the University of Science and Technology of China, Hefei National Laboratory for Physical Sciences at Microscale, Chinese Academy of Sciences Key Laboratory of Innate Immunity and Chronic Diseases, School of Life Sciences, Chinese Academy of Sciences Center for Excellence in Molecular Cell Science, Collaborative Innovation Center of Genetics and Development, University of Science and Technology of China, Hefei 230027, China
| | - Qinghua Shi
- First Affiliated Hospital of the University of Science and Technology of China, Hefei National Laboratory for Physical Sciences at Microscale, Chinese Academy of Sciences Key Laboratory of Innate Immunity and Chronic Diseases, School of Life Sciences, Chinese Academy of Sciences Center for Excellence in Molecular Cell Science, Collaborative Innovation Center of Genetics and Development, University of Science and Technology of China, Hefei 230027, China
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61
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Sur-Erdem I, Hussain MS, Asif M, Pınarbası N, Aksu AC, Noegel AA. Nesprin-1 impact on tumorigenic cell phenotypes. Mol Biol Rep 2019; 47:921-934. [PMID: 31741263 DOI: 10.1007/s11033-019-05184-w] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2019] [Accepted: 11/07/2019] [Indexed: 12/24/2022]
Abstract
The largest protein of the nuclear envelope (NE) is Nesprin-1 which forms a network along the NE interacting with actin, Emerin, Lamin, and SUN proteins. Mutations in the SYNE1 gene and reduction in Nesprin-1 protein levels have been reported to correlate with several age related diseases and cancer. In the present study, we tested whether Nesprin-1 overexpression can reverse the malignant phenotype of Huh7 cells, a human liver cancer cell line, which carries a mutation in the SYNE1 gene resulting in reduced Nesprin-1 protein levels, has altered nuclear shape, altered amounts and localization of NE components, centrosome localization and genome stability. Ectopic expression of a mini-Nesprin-1 led to an improvement of the nuclear shape, corrected the mislocalization of NE proteins, the centrosome positioning, and the alterations in the DNA damage response network. Additionally, Nesprin-1 had a profound effect on cellular senescence. These findings suggest that Nesprin-1 may be effective in tumorigenic cell phenotype correction of human liver cancer.
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Affiliation(s)
- Ilknur Sur-Erdem
- Institute of Biochemistry I, Medical Faculty, University Hospital Cologne, Cologne, Germany. .,Center for Molecular Medicine Cologne (CMMC) and Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Cologne, Germany. .,Koç University School of Medicine, 34450, Istanbul, Turkey. .,Koç University Research Center for Translational Medicine (KUTTAM), Istanbul, Turkey.
| | - Muhammed Sajid Hussain
- Institute of Biochemistry I, Medical Faculty, University Hospital Cologne, Cologne, Germany.,Center for Molecular Medicine Cologne (CMMC) and Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Cologne, Germany.,Cologne Center for Genomics (CCG), University of Cologne, Cologne, Germany
| | - Maria Asif
- Institute of Biochemistry I, Medical Faculty, University Hospital Cologne, Cologne, Germany.,Center for Molecular Medicine Cologne (CMMC) and Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Cologne, Germany.,Cologne Center for Genomics (CCG), University of Cologne, Cologne, Germany
| | - Nareg Pınarbası
- Koç University School of Medicine, 34450, Istanbul, Turkey.,Koç University Research Center for Translational Medicine (KUTTAM), Istanbul, Turkey
| | - Ali Cenk Aksu
- Koç University School of Medicine, 34450, Istanbul, Turkey.,Koç University Research Center for Translational Medicine (KUTTAM), Istanbul, Turkey
| | - Angelika A Noegel
- Institute of Biochemistry I, Medical Faculty, University Hospital Cologne, Cologne, Germany.,Center for Molecular Medicine Cologne (CMMC) and Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Cologne, Germany
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62
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Thakar K, Carroll CW. Mkl1-dependent gene activation is sufficient to induce actin cap assembly. Small GTPases 2019; 10:433-440. [PMID: 28586283 PMCID: PMC6748361 DOI: 10.1080/21541248.2017.1328303] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2017] [Revised: 04/25/2017] [Accepted: 05/05/2017] [Indexed: 12/12/2022] Open
Abstract
Actin-dependent forces mechanically control both the position and shape of the nucleus. While the mechanisms that establish nuclear position are well defined, less understood is how actin filaments determine nuclear shape. We recently showed that nuclear envelope-spanning LINC complexes promote stress fiber assembly by activating the small GTPase RhoA and Mkl1-dependent gene activation. We now report that a subset of these stress fibers associate with the apical face of the nuclear envelope through LINC complexes that contain the inner nuclear membrane protein Sun2. Apical stress fibers have previously been shown to specifically couple cell and nuclear morphology, suggesting that LINC complexes influence nuclear shape in part by regulating the small GTPase RhoA.
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Affiliation(s)
- Ketan Thakar
- Department of Cell Biology, Yale School of Medicine, New Haven, CT, USA
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Capitanchik C, Dixon CR, Swanson SK, Florens L, Kerr ARW, Schirmer EC. Analysis of RNA-Seq datasets reveals enrichment of tissue-specific splice variants for nuclear envelope proteins. Nucleus 2019; 9:410-430. [PMID: 29912636 PMCID: PMC7000147 DOI: 10.1080/19491034.2018.1469351] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
Laminopathies yield tissue-specific pathologies, yet arise from mutation of ubiquitously-expressed genes. A little investigated hypothesis to explain this is that the mutated proteins or their partners have tissue-specific splice variants. To test this, we analyzed RNA-Seq datasets, finding novel isoforms or isoform tissue-specificity for: Lap2, linked to cardiomyopathy; Nesprin 2, linked to Emery-Dreifuss muscular dystrophy and Lmo7, that regulates the Emery-Dreifuss muscular dystrophy linked emerin gene. Interestingly, the muscle-specific Lmo7 exon is rich in serine phosphorylation motifs, suggesting regulatory function. Muscle-specific splice variants in non-nuclear envelope proteins linked to other muscular dystrophies were also found. Nucleoporins tissue-specific variants were found for Nup54, Nup133, Nup153 and Nup358/RanBP2. RT-PCR confirmed novel Lmo7 and RanBP2 variants and specific knockdown of the Lmo7 variantreduced myogenic index. Nuclear envelope proteins were enriched for tissue-specific splice variants compared to the rest of the genome, suggesting that splice variants contribute to its tissue-specific functions.
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Affiliation(s)
- Charlotte Capitanchik
- a The Wellcome Centre for Cell Biology and Institute of Cell Biology , University of Edinburgh , Edinburgh , UK
| | - Charles R Dixon
- a The Wellcome Centre for Cell Biology and Institute of Cell Biology , University of Edinburgh , Edinburgh , UK
| | - Selene K Swanson
- b Stowers Institute for Medical Research , Kansas City , MO , USA
| | - Laurence Florens
- b Stowers Institute for Medical Research , Kansas City , MO , USA
| | - Alastair R W Kerr
- a The Wellcome Centre for Cell Biology and Institute of Cell Biology , University of Edinburgh , Edinburgh , UK
| | - Eric C Schirmer
- a The Wellcome Centre for Cell Biology and Institute of Cell Biology , University of Edinburgh , Edinburgh , UK
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64
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Mroß C, Marko M, Munck M, Glöckner G, Motameny S, Altmüller J, Noegel AA, Eichinger L, Peche VS, Neumann S. Depletion of Nesprin-2 is associated with an embryonic lethal phenotype in mice. Nucleus 2019; 9:503-515. [PMID: 30220251 PMCID: PMC6244730 DOI: 10.1080/19491034.2018.1523664] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Nesprin-2 is a nuclear envelope component and provides a link between cytoskeletal components of the cytoplasm and the nucleoplasm. Several isoforms are generated from its gene Syne2. Loss of the largest isoform Nesprin-2 Giant in mice is associated with a skin phenotype and altered wound healing, loss of C-terminal isoforms in mice leads to cardiomyopathies and neurological defects. Here we attempted to establish mice with an inducible knockout of all Nesprin-2 isoforms by inserting shRNA encoding sequences targeting the N- and C-terminus into the ROSA26 locus of mice. This caused early embryonic death of the animals harboring the mutant allele, which was presumably due to leaky expression of the shRNAs. Mutant embryos were only observed before E13. They had an altered appearance and were smaller in size than their wild type littermates. From this we conclude that the Nesprin-2 gene function is crucial during embryonic growth, differentiation and organogenesis.
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Affiliation(s)
- Carmen Mroß
- a Institute of Biochemistry I, Medical Faculty , University Hospital Cologne; Center for Molecular Medicine Cologne (CMMC) and Cologne Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD) , Koeln , Germany
| | - Marija Marko
- a Institute of Biochemistry I, Medical Faculty , University Hospital Cologne; Center for Molecular Medicine Cologne (CMMC) and Cologne Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD) , Koeln , Germany
| | - Martina Munck
- a Institute of Biochemistry I, Medical Faculty , University Hospital Cologne; Center for Molecular Medicine Cologne (CMMC) and Cologne Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD) , Koeln , Germany
| | - Gernot Glöckner
- a Institute of Biochemistry I, Medical Faculty , University Hospital Cologne; Center for Molecular Medicine Cologne (CMMC) and Cologne Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD) , Koeln , Germany
| | - Susanne Motameny
- b Cologne Center for Genomics (CCG) , University of Cologne , Koeln , Germany
| | - Janine Altmüller
- b Cologne Center for Genomics (CCG) , University of Cologne , Koeln , Germany
| | - Angelika A Noegel
- a Institute of Biochemistry I, Medical Faculty , University Hospital Cologne; Center for Molecular Medicine Cologne (CMMC) and Cologne Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD) , Koeln , Germany
| | - Ludwig Eichinger
- a Institute of Biochemistry I, Medical Faculty , University Hospital Cologne; Center for Molecular Medicine Cologne (CMMC) and Cologne Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD) , Koeln , Germany
| | - Vivek S Peche
- a Institute of Biochemistry I, Medical Faculty , University Hospital Cologne; Center for Molecular Medicine Cologne (CMMC) and Cologne Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD) , Koeln , Germany
| | - Sascha Neumann
- a Institute of Biochemistry I, Medical Faculty , University Hospital Cologne; Center for Molecular Medicine Cologne (CMMC) and Cologne Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD) , Koeln , Germany
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65
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The NAE Pathway: Autobahn to the Nucleus for Cell Surface Receptors. Cells 2019; 8:cells8080915. [PMID: 31426451 PMCID: PMC6721735 DOI: 10.3390/cells8080915] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2019] [Revised: 08/13/2019] [Accepted: 08/13/2019] [Indexed: 12/19/2022] Open
Abstract
Various growth factors and full-length cell surface receptors such as EGFR are translocated from the cell surface to the nucleoplasm, baffling cell biologists to the mechanisms and functions of this process. Elevated levels of nuclear EGFR correlate with poor prognosis in various cancers. In recent years, nuclear EGFR has been implicated in regulating gene transcription, cell proliferation and DNA damage repair. Different models have been proposed to explain how the receptors are transported into the nucleus. However, a clear consensus has yet to be reached. Recently, we described the nuclear envelope associated endosomes (NAE) pathway, which delivers EGFR from the cell surface to the nucleus. This pathway involves transport, docking and fusion of NAEs with the outer membrane of the nuclear envelope. EGFR is then presumed to be transported through the nuclear pore complex, extracted from membranes and solubilised. The SUN1/2 nuclear envelope proteins, Importin-beta, nuclear pore complex proteins and the Sec61 translocon have been implicated in the process. While this framework can explain the cell surface to nucleus traffic of EGFR and other cell surface receptors, it raises several questions that we consider in this review, together with implications for health and disease.
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66
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Caporizzo MA, Chen CY, Prosser BL. Cardiac microtubules in health and heart disease. Exp Biol Med (Maywood) 2019; 244:1255-1272. [PMID: 31398994 DOI: 10.1177/1535370219868960] [Citation(s) in RCA: 74] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Cardiomyocytes are large (∼40,000 µm3), rod-shaped muscle cells that provide the working force behind each heartbeat. These highly structured cells are packed with dense cytoskeletal networks that can be divided into two groups—the contractile (i.e. sarcomeric) cytoskeleton that consists of filamentous actin-myosin arrays organized into myofibrils, and the non-sarcomeric cytoskeleton, which is composed of β- and γ-actin, microtubules, and intermediate filaments. Together, microtubules and intermediate filaments form a cross-linked scaffold, and these networks are responsible for the delivery of intracellular cargo, the transmission of mechanical signals, the shaping of membrane systems, and the organization of myofibrils and organelles. Microtubules are extensively altered as part of both adaptive and pathological cardiac remodeling, which has diverse ramifications for the structure and function of the cardiomyocyte. In heart failure, the proliferation and post-translational modification of the microtubule network is linked to a number of maladaptive processes, including the mechanical impediment of cardiomyocyte contraction and relaxation. This raises the possibility that reversing microtubule alterations could improve cardiac performance, yet therapeutic efforts will strongly benefit from a deeper understanding of basic microtubule biology in the heart. The aim of this review is to summarize the known physiological roles of the cardiomyocyte microtubule network, the consequences of its pathological remodeling, and to highlight the open and intriguing questions regarding cardiac microtubules. Impact statement Advancements in cell biological and biophysical approaches and super-resolution imaging have greatly broadened our view of tubulin biology over the last decade. In the heart, microtubules and microtubule-based transport help to organize and maintain key structures within the cardiomyocyte, including the sarcomere, intercalated disc, protein clearance machinery and transverse-tubule and sarcoplasmic reticulum membranes. It has become increasingly clear that post translational regulation of microtubules is a key determinant of their sub-cellular functionality. Alterations in microtubule network density, stability, and post-translational modifications are hallmarks of pathological cardiac remodeling, and modified microtubules can directly impede cardiomyocyte contractile function in various forms of heart disease. This review summarizes the functional roles and multi-leveled regulation of the cardiac microtubule cytoskeleton and highlights how refined experimental techniques are shedding mechanistic clarity on the regionally specified roles of microtubules in cardiac physiology and pathophysiology.
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Affiliation(s)
- Matthew A Caporizzo
- Department of Physiology, Pennsylvania Muscle Institute, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA
| | - Christina Yingxian Chen
- Department of Physiology, Pennsylvania Muscle Institute, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA
| | - Benjamin L Prosser
- Department of Physiology, Pennsylvania Muscle Institute, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA.,Penn Cardiovascular Institute, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA
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67
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Östlund C, Chang W, Gundersen GG, Worman HJ. Pathogenic mutations in genes encoding nuclear envelope proteins and defective nucleocytoplasmic connections. Exp Biol Med (Maywood) 2019; 244:1333-1344. [PMID: 31299860 DOI: 10.1177/1535370219862243] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Mutations in genes encoding nuclear lamins and associated nuclear envelope proteins have been linked to a broad range of inherited diseases affecting different tissues and organs. These diseases are often referred to as laminopathies. Scientists have yet to elucidate exactly how pathogenic mutations leading to alteration of a nuclear envelope protein cause disease. Our relatively recent research has shown that pathogenic mutations in genes encoding nuclear envelope proteins lead to defective nucleocytoplasmic connections that disrupt proper functioning of the linker of nucleoskeleton and cytoskeleton complex in the establishment of cell polarity. These defects may explain, at least in part, pathogenic mechanisms underlying laminopathies.Impact statementMutations in genes encoding nuclear lamins and associated nuclear envelope proteins have been linked to several diseases affecting different tissues and organs. The pathogenic mechanisms underlying these diseases, often called laminopathies, remain poorly understood. Increased knowledge of the functions of different nuclear envelope proteins and the interactions between them is crucial to elucidate these disease mechanisms. Our research has shown that pathogenic mutations in genes encoding nuclear envelope proteins lead to defective nucleocytoplasmic connections that disrupt proper functioning of the linker of nucleoskeleton and cytoskeleton (LINC) complex in the establishment of cell polarity. These defects may contribute to the pathogenesis of laminopathies and provide novel targets for therapeutics.
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Affiliation(s)
- Cecilia Östlund
- Department of Medicine, Vagelos College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA.,Department of Pathology and Cell Biology, Vagelos College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA
| | - Wakam Chang
- Department of Pathology and Cell Biology, Vagelos College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA
| | - Gregg G Gundersen
- Department of Pathology and Cell Biology, Vagelos College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA
| | - Howard J Worman
- Department of Medicine, Vagelos College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA.,Department of Pathology and Cell Biology, Vagelos College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA
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68
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Sidorenko E, Vartiainen MK. Nucleoskeletal regulation of transcription: Actin on MRTF. Exp Biol Med (Maywood) 2019; 244:1372-1381. [PMID: 31142145 DOI: 10.1177/1535370219854669] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
Myocardin-related transcription factor A (MRTF-A) and serum response factor (SRF) form an essential transcriptional complex that regulates the expression of many cytoskeletal genes in response to dynamic changes in the actin cytoskeleton. The nucleoskeleton, a “dynamic network of networks,” consists of numerous proteins that contribute to nuclear shape and to its various functions, including gene expression. In this review, we will discuss recent work that has identified many nucleoskeletal proteins, such as nuclear lamina and lamina-associated proteins, nuclear actin, and the linker of the cytoskeleton and nucleoskeleton complex as important regulators of MRTF-A/SRF transcriptional activity, especially in the context of mechanical control of transcription. Impact statement Regulation of gene expression is a fundamental cellular process that ensures the appropriate response of a cell to its surroundings. Alongside biochemical signals, mechanical cues, such as substrate rigidity, have been recognized as key regulators of gene expression. Nucleoskeletal components play an important role in mechanoresponsive transcription, particularly in controlling the activity of MRTF-A/SRF transcription factors. This ensures that the cell can balance the internal and external mechanical forces by fine-tuning the expression of cytoskeletal genes.
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Affiliation(s)
- Ekaterina Sidorenko
- Institute of Biotechnology, Helsinki Institute of Life Science, University of Helsinki, Helsinki 00014, Finland
| | - Maria K Vartiainen
- Institute of Biotechnology, Helsinki Institute of Life Science, University of Helsinki, Helsinki 00014, Finland
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69
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Sola-Carvajal A, Revêchon G, Helgadottir HT, Whisenant D, Hagblom R, Döhla J, Katajisto P, Brodin D, Fagerström-Billai F, Viceconte N, Eriksson M. Accumulation of Progerin Affects the Symmetry of Cell Division and Is Associated with Impaired Wnt Signaling and the Mislocalization of Nuclear Envelope Proteins. J Invest Dermatol 2019; 139:2272-2280.e12. [PMID: 31128203 DOI: 10.1016/j.jid.2019.05.005] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2018] [Revised: 05/02/2019] [Accepted: 05/08/2019] [Indexed: 12/17/2022]
Abstract
Hutchinson-Gilford progeria syndrome (HGPS) is the result of a defective form of the lamin A protein called progerin. While progerin is known to disrupt the properties of the nuclear lamina, the underlying mechanisms responsible for the pathophysiology of HGPS remain less clear. Previous studies in our laboratory have shown that progerin expression in murine epidermal basal cells results in impaired stratification and halted development of the skin. Stratification and differentiation of the epidermis is regulated by asymmetric stem cell division. Here, we show that expression of progerin impairs the ability of stem cells to maintain tissue homeostasis as a result of altered cell division. Quantification of basal skin cells showed an increase in symmetric cell division that correlated with progerin accumulation in HGPS mice. Investigation of the mechanisms underlying this phenomenon revealed a putative role of Wnt/β-catenin signaling. Further analysis suggested an alteration in the nuclear translocation of β-catenin involving the inner and outer nuclear membrane proteins, emerin and nesprin-2. Taken together, our results suggest a direct involvement of progerin in the transmission of Wnt signaling and normal stem cell division. These insights into the molecular mechanisms of progerin may help develop new treatment strategies for HGPS.
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Affiliation(s)
- Agustín Sola-Carvajal
- Department of Biosciences and Nutrition, Center for Innovative Medicine, Karolinska Institutet, Huddinge, Sweden.
| | - Gwladys Revêchon
- Department of Biosciences and Nutrition, Center for Innovative Medicine, Karolinska Institutet, Huddinge, Sweden
| | - Hafdis T Helgadottir
- Department of Biosciences and Nutrition, Center for Innovative Medicine, Karolinska Institutet, Huddinge, Sweden
| | - Daniel Whisenant
- Department of Biosciences and Nutrition, Center for Innovative Medicine, Karolinska Institutet, Huddinge, Sweden
| | - Robin Hagblom
- Department of Biosciences and Nutrition, Center for Innovative Medicine, Karolinska Institutet, Huddinge, Sweden
| | - Julia Döhla
- Department of Biosciences and Nutrition, Center for Innovative Medicine, Karolinska Institutet, Huddinge, Sweden; Institute of Biotechnology, University of Helsinki, Helsinki, Finland
| | - Pekka Katajisto
- Department of Biosciences and Nutrition, Center for Innovative Medicine, Karolinska Institutet, Huddinge, Sweden; Institute of Biotechnology, University of Helsinki, Helsinki, Finland
| | - David Brodin
- Bioinformatics and Expression Core Facility, Karolinska Institutet, Huddinge, Sweden
| | | | - Nikenza Viceconte
- Department of Biosciences and Nutrition, Center for Innovative Medicine, Karolinska Institutet, Huddinge, Sweden
| | - Maria Eriksson
- Department of Biosciences and Nutrition, Center for Innovative Medicine, Karolinska Institutet, Huddinge, Sweden.
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70
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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: 1.8] [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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71
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Chalfant M, Barber KW, Borah S, Thaller D, Lusk CP. Expression of TorsinA in a heterologous yeast system reveals interactions with lumenal domains of LINC and nuclear pore complex components. Mol Biol Cell 2019; 30:530-541. [PMID: 30625036 PMCID: PMC6589686 DOI: 10.1091/mbc.e18-09-0585] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
DYT1 dystonia is caused by an in-frame deletion of a glutamic acid codon in the gene encoding the AAA+ ATPase TorsinA (TorA). TorA localizes within the lumen of the nuclear envelope/endoplasmic reticulum and binds to a membrane-spanning cofactor, lamina associated polypeptide 1 (LAP1) or lumenal domain like LAP1 (LULL1), to form an ATPase; the substrate(s) of TorA remains ill-defined. Here we use budding yeast, which lack Torsins, to interrogate TorA function. We show that TorA accumulates at nuclear envelope-embedded spindle pole bodies (SPBs) in a way that requires its oligomerization and the SUN (Sad1 and UNc-84)-domain protein, Mps3. We further show that TorA physically interacts with human SUN1/2 within this system, supporting the physiological relevance of these interactions. Consistent with the idea that TorA acts on a SPB substrate, its binding to SPBs is modulated by the ATPase-stimulating activity of LAP1. TorA and TorA-ΔE reduce the fitness of cells expressing mps3 alleles, whereas TorA alone inhibits growth of cells lacking Pom152, a component of the nuclear pore complex. This genetic specificity is mirrored biochemically as TorA, but not TorA-ΔE, binds Pom152. Thus, TorA–nucleoporin interactions might be abrogated by TorA-ΔE, suggesting new experimental avenues to interrogate the molecular basis behind nuclear envelope herniations seen in mammalian cells lacking TorA function.
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Affiliation(s)
| | - Karl W. Barber
- Department of Cellular and Molecular Physiology, Yale School of Medicine, Yale University, New Haven, CT 06520
- Systems Biology Institute, Yale University, West Haven, CT 06477
| | - Sapan Borah
- Department of Cell Biology, Yale University, New Haven, CT 06520
| | - David Thaller
- Department of Cell Biology, Yale University, New Haven, CT 06520
| | - C. Patrick Lusk
- Department of Cell Biology, Yale University, New Haven, CT 06520
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72
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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: 4.2] [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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Abstract
Nuclear positioning plays an essential role in defining cell architecture and behaviour in both development and disease, and nuclear location frequently adjusts according to internal and external cues. For instance, during periods of migration in many cell types, the nucleus may be actively repositioned behind the microtubule-organising centre. Nuclear movement, for the most part, is dependent upon coupling of the cytoskeleton to the nuclear periphery. This is accomplished largely through SUN and KASH domain proteins, which together assemble to form LINC (linker of the nucleoskeleton and cytoskeleton) complexes spanning the nuclear envelope. SUN proteins of the inner nuclear membrane provide a connection to nuclear structures while acting as a tether for outer nuclear membrane KASH proteins. The latter contain binding sites for diverse cytoskeletal components. Recent publications highlight new aspects of LINC complex regulation revealing that the interplay between SUN and KASH partners can strongly influence how the nucleus functionally engages with different branches of the cytoskeleton.
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Affiliation(s)
- Brian Burke
- Institute for Medical Biology, 8A Biomedical Grove, #06-06 Immunos , 138648, Singapore
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74
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Manley HR, Keightley MC, Lieschke GJ. The Neutrophil Nucleus: An Important Influence on Neutrophil Migration and Function. Front Immunol 2018; 9:2867. [PMID: 30564248 PMCID: PMC6288403 DOI: 10.3389/fimmu.2018.02867] [Citation(s) in RCA: 74] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2018] [Accepted: 11/21/2018] [Indexed: 11/13/2022] Open
Abstract
Neutrophil nuclear morphology has historically been used in haematology for neutrophil identification and characterisation, but its exact role in neutrophil function has remained enigmatic. During maturation, segmentation of the neutrophil nucleus into its mature, multi-lobulated shape is accompanied by distinct changes in nuclear envelope composition, resulting in a unique nucleus that is believed to be imbued with extraordinary nuclear flexibility. As a rate-limiting factor for cell migration, nuclear morphology and biomechanics are particularly important in the context of neutrophil migration during immune responses. Being an extremely plastic and fast migrating cell type, it is to be expected that neutrophils have an especially deformable nucleus. However, many questions still surround the dynamic capacities of the neutrophil nucleus, and which nuclear and cytoskeletal elements determine these dynamics. The biomechanics of the neutrophil nucleus should also be considered for their influences on the production of neutrophil extracellular traps (NETs), given this process sees the release of chromatin "nets" from nucleoplasm to extracellular space. Although past studies have investigated neutrophil nuclear composition and shape, in a new era of more sophisticated biomechanical and genetic techniques, 3D migration studies, and higher resolution microscopy we now have the ability to further investigate and understand neutrophil nuclear plasticity at an unprecedented level. This review addresses what is currently understood about neutrophil nuclear structure and its role in migration and the release of NETs, whilst highlighting open questions surrounding neutrophil nuclear dynamics.
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Affiliation(s)
- Harriet R Manley
- Australian Regenerative Medicine Institute, Monash University, Clayton, VIC, Australia
| | | | - Graham J Lieschke
- Australian Regenerative Medicine Institute, Monash University, Clayton, VIC, Australia
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75
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Chen X, Chen Y, Huang HM, Li HD, Bu FT, Pan XY, Yang Y, Li WX, Li XF, Huang C, Meng XM, Li J. SUN2: A potential therapeutic target in cancer. Oncol Lett 2018; 17:1401-1408. [PMID: 30675193 PMCID: PMC6341589 DOI: 10.3892/ol.2018.9764] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2017] [Accepted: 04/30/2018] [Indexed: 12/24/2022] Open
Abstract
The incidence of cancer is increasing at an alarming rate despite recent advances in prevention strategies, diagnostics and therapeutics for various types of cancer. The identification of novel biomarkers to aid in prognosis and treatment for cancer is urgently required. Uncontrolled proliferation and dysregulated apoptosis are characteristics exhibited by cancer cells in the initiation of various types of cancer. Notably, aberrant expression of crucial oncogenes or cancer suppressors is a defining event in cancer occurrence. Research has demonstrated that SAD1/UNC84 domain protein-2 (SUN2) serves a suppressive role in breast cancer, atypical teratoid/rhabdoid tumors and lung cancer progression. Furthermore, SUN2 inhibits cancer cell proliferation, migration and promotes apoptosis. Recent reports have also shown that SUN2 serves prominent roles in resistance to the excessive DNA damage that destabilizes the genome and promotes cancer development, and these functions of SUN2 are critical for evading initiation of cancer. Additionally, increasing evidence has demonstrated that SUN2 is involved in maintaining cell nuclear structure and appears to be a central component for organizing the natural nuclear architecture in cancer cells. The focus of the present review is to provide an overview on the pharmacological functions of SUN2 in cancers. These findings suggest that SUN2 may serve as a promising therapeutic target and novel predictive marker in various types of cancer.
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Affiliation(s)
- Xin Chen
- School of Pharmacy, Anhui Medical University, Hefei, Anhui 230032, P.R. China.,The Key Laboratory of Anti-inflammatory and Immune Medicines, Ministry of Education, Hefei, Anhui 230032, P.R. China.,Institute for Liver Diseases of Anhui Medical University, Hefei, Anhui 230032, P.R. China
| | - Yu Chen
- School of Pharmacy, Anhui Medical University, Hefei, Anhui 230032, P.R. China.,The Key Laboratory of Anti-inflammatory and Immune Medicines, Ministry of Education, Hefei, Anhui 230032, P.R. China.,Institute for Liver Diseases of Anhui Medical University, Hefei, Anhui 230032, P.R. China
| | - Hui-Min Huang
- School of Pharmacy, Anhui Medical University, Hefei, Anhui 230032, P.R. China.,The Key Laboratory of Anti-inflammatory and Immune Medicines, Ministry of Education, Hefei, Anhui 230032, P.R. China.,Institute for Liver Diseases of Anhui Medical University, Hefei, Anhui 230032, P.R. China
| | - Hai-Di Li
- School of Pharmacy, Anhui Medical University, Hefei, Anhui 230032, P.R. China.,The Key Laboratory of Anti-inflammatory and Immune Medicines, Ministry of Education, Hefei, Anhui 230032, P.R. China.,Institute for Liver Diseases of Anhui Medical University, Hefei, Anhui 230032, P.R. China
| | - Fang-Tian Bu
- School of Pharmacy, Anhui Medical University, Hefei, Anhui 230032, P.R. China.,The Key Laboratory of Anti-inflammatory and Immune Medicines, Ministry of Education, Hefei, Anhui 230032, P.R. China.,Institute for Liver Diseases of Anhui Medical University, Hefei, Anhui 230032, P.R. China
| | - Xue-Yin Pan
- School of Pharmacy, Anhui Medical University, Hefei, Anhui 230032, P.R. China.,The Key Laboratory of Anti-inflammatory and Immune Medicines, Ministry of Education, Hefei, Anhui 230032, P.R. China.,Institute for Liver Diseases of Anhui Medical University, Hefei, Anhui 230032, P.R. China
| | - Yang Yang
- School of Pharmacy, Anhui Medical University, Hefei, Anhui 230032, P.R. China.,The Key Laboratory of Anti-inflammatory and Immune Medicines, Ministry of Education, Hefei, Anhui 230032, P.R. China.,Institute for Liver Diseases of Anhui Medical University, Hefei, Anhui 230032, P.R. China
| | - Wan-Xia Li
- Department of Pharmacy, Anqing Municipal Hospital, Anqing, Anhui 246003, P.R. China
| | - Xiao-Feng Li
- School of Pharmacy, Anhui Medical University, Hefei, Anhui 230032, P.R. China.,The Key Laboratory of Anti-inflammatory and Immune Medicines, Ministry of Education, Hefei, Anhui 230032, P.R. China.,Institute for Liver Diseases of Anhui Medical University, Hefei, Anhui 230032, P.R. China
| | - Cheng Huang
- School of Pharmacy, Anhui Medical University, Hefei, Anhui 230032, P.R. China.,The Key Laboratory of Anti-inflammatory and Immune Medicines, Ministry of Education, Hefei, Anhui 230032, P.R. China.,Institute for Liver Diseases of Anhui Medical University, Hefei, Anhui 230032, P.R. China
| | - Xiao-Ming Meng
- School of Pharmacy, Anhui Medical University, Hefei, Anhui 230032, P.R. China.,The Key Laboratory of Anti-inflammatory and Immune Medicines, Ministry of Education, Hefei, Anhui 230032, P.R. China.,Institute for Liver Diseases of Anhui Medical University, Hefei, Anhui 230032, P.R. China
| | - Jun Li
- School of Pharmacy, Anhui Medical University, Hefei, Anhui 230032, P.R. China.,The Key Laboratory of Anti-inflammatory and Immune Medicines, Ministry of Education, Hefei, Anhui 230032, P.R. China.,Institute for Liver Diseases of Anhui Medical University, Hefei, Anhui 230032, P.R. China
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76
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Cruz-Teran CA, Bacon K, McArthur N, Rao BM. An Engineered Sso7d Variant Enables Efficient Magnetization of Yeast Cells. ACS COMBINATORIAL SCIENCE 2018; 20:579-584. [PMID: 30188690 DOI: 10.1021/acscombsci.8b00084] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Magnetization using cheap and minimally toxic materials, such as iron oxide nanoparticles can enable easy separation of cells from culture medium and is relevant to several industrial applications. Here, we show that cell surface expression of a mutant protein that binds iron oxide can enable efficient magnetization of yeast cells. We screened a combinatorial library of mutants derived from the Sso7d protein scaffold to isolate proteins that exhibit preferential binding to iron oxide. One of the isolated mutants, SsoFe2, was chosen for further characterization. Yeast cells expressing SsoFe2 as fusions to a cell wall protein-but not other Sso7d mutants with similar overall protein charge or amino acid composition-preferentially bind iron oxide when present in a solution with high protein concentration and in the presence of 1000-fold excess of competitor yeast cells. Moreover, coexpression of cell surface SsoFe2 enables efficient magnetic capture and separation of yeast cells expressing an enzyme (glucose oxidase) on the cell surface from yeast culture medium, and solutions with high protein concentration or containing other metal oxides. Therefore, SsoFe2-enabled magnetization can enable a range of industrial and biotechnology applications, where easy separation of cells or organelles from complex media is desirable.
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Affiliation(s)
- Carlos A. Cruz-Teran
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Box 7905, Engineering Building I, Raleigh, North Carolina 27695, United States
| | - Kaitlyn Bacon
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Box 7905, Engineering Building I, Raleigh, North Carolina 27695, United States
| | - Nikki McArthur
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Box 7905, Engineering Building I, Raleigh, North Carolina 27695, United States
| | - Balaji M. Rao
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Box 7905, Engineering Building I, Raleigh, North Carolina 27695, United States
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77
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Cain NE, Jahed Z, Schoenhofen A, Valdez VA, Elkin B, Hao H, Harris NJ, Herrera LA, Woolums BM, Mofrad MRK, Luxton GWG, Starr DA. Conserved SUN-KASH Interfaces Mediate LINC Complex-Dependent Nuclear Movement and Positioning. Curr Biol 2018; 28:3086-3097.e4. [PMID: 30245107 DOI: 10.1016/j.cub.2018.08.001] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2017] [Revised: 06/18/2018] [Accepted: 08/01/2018] [Indexed: 12/20/2022]
Abstract
Many nuclear positioning events involve linker of nucleoskeleton and cytoskeleton (LINC) complexes, which transmit forces generated by the cytoskeleton across the nuclear envelope. LINC complexes are formed by trans-luminal interactions between inner nuclear membrane SUN proteins and outer nuclear membrane KASH proteins, but how these interactions are regulated is poorly understood. We combine in vivo C. elegans genetics, in vitro wounded fibroblast polarization, and in silico molecular dynamics simulations to elucidate mechanisms of LINC complexes. The extension of the KASH domain by a single alanine residue or the mutation of the conserved tyrosine at -7 completely blocked the nuclear migration function of C. elegans UNC-83. Analogous mutations at -7 of mouse nesprin-2 disrupted rearward nuclear movements in NIH 3T3 cells, but did not disrupt ANC-1 in nuclear anchorage. Furthermore, conserved cysteines predicted to form a disulfide bond between SUN and KASH proteins are important for the function of certain LINC complexes, and might promote a developmental switch between nuclear migration and nuclear anchorage. Mutations of conserved cysteines in SUN or KASH disrupted ANC-1-dependent nuclear anchorage in C. elegans and Nesprin-2G-dependent nuclear movements in polarizing fibroblasts. However, the SUN cysteine mutation did not disrupt nuclear migration. Moreover, molecular dynamics simulations showed that a disulfide bond is necessary for the maximal transmission of cytoskeleton-generated forces by LINC complexes in silico. Thus, we have demonstrated functions for SUN-KASH binding interfaces, including a predicted intermolecular disulfide bond, as mechanistic determinants of nuclear positioning that may represent targets for regulation.
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Affiliation(s)
- Natalie E Cain
- Department of Molecular and Cellular Biology, University of California, Davis, 1 Shields Avenue, Davis, CA 95616, USA
| | - Zeinab Jahed
- Molecular Cell Biomechanics Laboratory, Departments of Bioengineering and Mechanical Engineering, University of California, Berkeley, 208A Stanley Hall, Berkeley, CA 94720, USA
| | - Amy Schoenhofen
- Department of Genetics, Cell Biology, and Development, University of Minnesota, 420 Washington Avenue SE, Minneapolis, MN 55455, USA
| | - Venecia A Valdez
- Department of Molecular and Cellular Biology, University of California, Davis, 1 Shields Avenue, Davis, CA 95616, USA
| | - Baila Elkin
- Department of Genetics, Cell Biology, and Development, University of Minnesota, 420 Washington Avenue SE, Minneapolis, MN 55455, USA
| | - Hongyan Hao
- Department of Molecular and Cellular Biology, University of California, Davis, 1 Shields Avenue, Davis, CA 95616, USA
| | - Nathan J Harris
- Department of Genetics, Cell Biology, and Development, University of Minnesota, 420 Washington Avenue SE, Minneapolis, MN 55455, USA
| | - Leslie A Herrera
- Department of Molecular and Cellular Biology, University of California, Davis, 1 Shields Avenue, Davis, CA 95616, USA
| | - Brian M Woolums
- Department of Genetics, Cell Biology, and Development, University of Minnesota, 420 Washington Avenue SE, Minneapolis, MN 55455, USA
| | - Mohammad R K Mofrad
- Molecular Cell Biomechanics Laboratory, Departments of Bioengineering and Mechanical Engineering, University of California, Berkeley, 208A Stanley Hall, Berkeley, CA 94720, USA
| | - G W Gant Luxton
- Department of Genetics, Cell Biology, and Development, University of Minnesota, 420 Washington Avenue SE, Minneapolis, MN 55455, USA
| | - Daniel A Starr
- Department of Molecular and Cellular Biology, University of California, Davis, 1 Shields Avenue, Davis, CA 95616, USA.
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78
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Janin A, Gache V. Nesprins and Lamins in Health and Diseases of Cardiac and Skeletal Muscles. Front Physiol 2018; 9:1277. [PMID: 30245638 PMCID: PMC6137955 DOI: 10.3389/fphys.2018.01277] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2018] [Accepted: 08/22/2018] [Indexed: 12/26/2022] Open
Abstract
Since the discovery of the inner nuclear transmembrane protein emerin in the early 1990s, nuclear envelope (NE) components and related involvement in nuclei integrity and functionality have been highly investigated. The NE is composed of two distinct lipid bilayers described as the inner (INM) and outer (ONM) nuclear membrane. NE proteins can be specifically “integrated” in the INM (such as emerin and SUN proteins) or in the ONM such as nesprins. Additionally, flanked to the INM, the nuclear lamina, a proteinaceous meshwork mainly composed of lamins A and C completes NE composition. This network of proteins physically interplays to guarantee NE integrity and most importantly, shape the bridge between cytoplasmic cytoskeletons networks (such as microtubules and actin) and the genome, through the anchorage to the heterochromatin. The essential network driving the connection of nucleoskeleton with cytoskeleton takes place in the perinuclear space (the space between ONM and INM) with the contribution of the LINC complex (for Linker of Nucleoskeleton to Cytoskeleton), hosting KASH and SUN proteins interactions. This close interplay between compartments has been related to diverse functions from nuclear integrity, activity and positioning through mechanotransduction pathways. At the same time, mutations in NE components genes coding for proteins such as lamins or nesprins, had been associated with a wide range of congenital diseases including cardiac and muscular diseases. Although most of these NE associated proteins are ubiquitously expressed, a large number of tissue-specific disorders have been associated with diverse pathogenic mutations. Thus, diagnosis and molecular explanation of this group of diseases, commonly called “nuclear envelopathies,” is currently challenging. This review aims, first, to give a better understanding of diverse functions of the LINC complex components, from the point of view of lamins and nesprins. Second, to summarize human congenital diseases with a special focus on muscle and heart abnormalities, caused by mutations in genes coding for these two types of NE associated proteins.
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Affiliation(s)
- Alexandre Janin
- CNRS UMR5310, INSERM U1217, Institut NeuroMyoGène, Université Claude Bernard Lyon 1, Université de Lyon, Lyon, France.,Laboratoire de Cardiogénétique Moléculaire, Centre de Biologie et Pathologie Est, Hospices Civils de Lyon, Bron, France
| | - Vincent Gache
- CNRS UMR5310, INSERM U1217, Institut NeuroMyoGène, Université Claude Bernard Lyon 1, Université de Lyon, Lyon, France
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79
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Chambers DM, Moretti L, Zhang JJ, Cooper SW, Chambers DM, Santangelo PJ, Barker TH. LEM domain-containing protein 3 antagonizes TGFβ-SMAD2/3 signaling in a stiffness-dependent manner in both the nucleus and cytosol. J Biol Chem 2018; 293:15867-15886. [PMID: 30108174 DOI: 10.1074/jbc.ra118.003658] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2018] [Revised: 07/31/2018] [Indexed: 12/28/2022] Open
Abstract
Transforming growth factor-β (TGFβ) signaling through SMAD2/3 is an important driver of pathological fibrosis in multiple organ systems. TGFβ signaling and extracellular matrix (ECM) stiffness form an unvirtuous pathological circuit in which matrix stiffness drives activation of latent TGFβ, and TGFβ signaling then drives cellular stress and ECM synthesis. Moreover, ECM stiffness also appears to sensitize cells to exogenously activated TGFβ through unknown mechanisms. Here, using human fibroblasts, we explored the effect of ECM stiffness on a putative inner nuclear membrane protein, LEM domain-containing protein 3 (LEMD3), which is physically connected to the cell's actin cytoskeleton and inhibits TGFβ signaling. We showed that LEMD3-SMAD2/3 interactions are inversely correlated with ECM stiffness and TGFβ-driven luciferase activity and that LEMD3 expression is correlated with the mechanical response of the TGFβ-driven luciferase reporter. We found that actin polymerization but not cellular stress or LEMD3-nuclear-cytoplasmic couplings were necessary for LEMD3-SMAD2/3 interactions. Intriguingly, LEMD3 and SMAD2/3 frequently interacted in the cytosol, and we discovered LEMD3 was proteolytically cleaved into protein fragments. We confirmed that a consensus C-terminal LEMD3 fragment binds SMAD2/3 in a stiffness-dependent manner throughout the cell and is sufficient for antagonizing SMAD2/3 signaling. Using human lung biopsies, we observed that these nuclear and cytosolic interactions are also present in tissue and found that fibrotic tissues exhibit locally diminished and cytoplasmically shifted LEMD3-SMAD2/3 interactions, as noted in vitro Our work reveals novel LEMD3 biology and stiffness-dependent regulation of TGFβ by LEMD3, providing a novel target to antagonize pathological TGFβ signaling.
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Affiliation(s)
- Dwight M Chambers
- From the Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University School of Medicine, Atlanta, Georgia 30332
| | - Leandro Moretti
- Biomedical Engineering, University of Virginia, Charlottesville, Virginia 22908, and
| | - Jennifer J Zhang
- From the Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University School of Medicine, Atlanta, Georgia 30332
| | - Spencer W Cooper
- From the Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University School of Medicine, Atlanta, Georgia 30332
| | - Davis M Chambers
- the College of Arts and Sciences, Georgia State University, Atlanta, Georgia 30303
| | - Philip J Santangelo
- From the Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University School of Medicine, Atlanta, Georgia 30332
| | - Thomas H Barker
- Biomedical Engineering, University of Virginia, Charlottesville, Virginia 22908, and
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80
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Dieffenbach PB, Maracle M, Tschumperlin DJ, Fredenburgh LE. Mechanobiological Feedback in Pulmonary Vascular Disease. Front Physiol 2018; 9:951. [PMID: 30090065 PMCID: PMC6068271 DOI: 10.3389/fphys.2018.00951] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2018] [Accepted: 06/28/2018] [Indexed: 01/06/2023] Open
Abstract
Vascular stiffening in the pulmonary arterial bed is increasingly recognized as an early disease marker and contributor to right ventricular workload in pulmonary hypertension. Changes in pulmonary artery stiffness throughout the pulmonary vascular tree lead to physiologic alterations in pressure and flow characteristics that may contribute to disease progression. These findings have led to a greater focus on the potential contributions of extracellular matrix remodeling and mechanical signaling to pulmonary hypertension pathogenesis. Several recent studies have demonstrated that the cellular response to vascular stiffness includes upregulation of signaling pathways that precipitate further vascular remodeling, a process known as mechanobiological feedback. The extracellular matrix modifiers, mechanosensors, and mechanotransducers responsible for this process have become increasingly well-recognized. In this review, we discuss the impact of vascular stiffening on pulmonary hypertension morbidity and mortality, evidence in favor of mechanobiological feedback in pulmonary hypertension pathogenesis, and the major contributors to mechanical signaling in the pulmonary vasculature.
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Affiliation(s)
- Paul B Dieffenbach
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, Brigham and Women's Hospital, Boston, MA, United States
| | - Marcy Maracle
- Schulich School of Medicine and Dentistry, Western University, London, ON, Canada
| | - Daniel J Tschumperlin
- Department of Physiology and Biomedical Engineering, Mayo Clinic College of Medicine and Science, Rochester, MN, United States
| | - Laura E Fredenburgh
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, Brigham and Women's Hospital, Boston, MA, United States
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81
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Jahed Z, Vu UT, Fadavi D, Ke H, Rathish A, Kim SCJ, Feng W, Mofrad MRK. A molecular model for LINC complex regulation: activation of SUN2 for KASH binding. Mol Biol Cell 2018; 29:2012-2023. [PMID: 29995584 PMCID: PMC6232973 DOI: 10.1091/mbc.e18-04-0266] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Linkers of the nucleoskeleton and cytoskeleton are key molecular complexes that span the nuclear envelope (NE) and provide a direct linkage between the nucleoskeleton and cytoskeleton. Two major components of these complexes are members of the SUN and KASH protein families that interact in the perinuclear space to allow the transmission of mechanochemical signals across the NE. Structural details of the mammalian SUN domain protein SUN2 have established that SUN2 must form a trimer to bind to KASH, and that this trimerization is mediated through two predicted coiled-coil regions of the protein, CC1 and CC2, which precede the SUN domain. Recent crystallographic data suggest that CC2-SUN formed an unexpected autoinhibited monomer unable to bind to KASH. These structural insights raise the question of how full-length SUN2 transitions from a monomer to a trimer inside the NE. In this study we used a computational approach to model a fragment of SUN2 containing CC1, CC2, and the SUN domain. We observed the dynamics of these modeled structures using ∼1 μs molecular dynamics simulations and showed that the interplay between CC1 and CC2 may be sufficient for the release of CC2-SUN2 from its autoinhibited state. Additionally, using our models and gel filtration analysis, we show the involvement of an E452 residue on CC1 in the monomer–trimer transition of SUN2. Intriguingly, mutations in this residue have been seen in muscular dystrophy–associated SUN2 variants. Finally, we propose a Ca2+-dependent monomer–trimer transition of SUN2.
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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
| | - Uyen T Vu
- 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
| | - Huimin Ke
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
| | - Akshay Rathish
- 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
| | - Wei Feng
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
| | - 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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82
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Affiliation(s)
- Parthiv Kant Chaudhuri
- Mechanobiology Institute, National University of Singapore, 5A Engineering Drive 1, Level 9, Singapore 117411, Singapore
- Department of Biomedical Engineering, Columbia University, New York, New York 10027, United States
| | - Boon Chuan Low
- Mechanobiology Institute, National University of Singapore, 5A Engineering Drive 1, Level 9, Singapore 117411, Singapore
- Cell Signaling and Developmental Biology Laboratory, Department of Biological Sciences, National University of Singapore, Singapore 117558, Singapore
- University Scholars Programme, National University of Singapore, Singapore 138593, Singapore
| | - Chwee Teck Lim
- Mechanobiology Institute, National University of Singapore, 5A Engineering Drive 1, Level 9, Singapore 117411, Singapore
- Department of Biomedical Engineering, National University of Singapore, Singapore 117583, Singapore
- Biomedical Institute for Global Health Research and Technology (BIGHEART), National University of Singapore, Singapore 117599, Singapore
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83
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Smith ED, Garza-Gongora AG, MacQuarrie KL, Kosak ST. Interstitial telomeric loops and implications of the interaction between TRF2 and lamin A/C. Differentiation 2018; 102:19-26. [PMID: 29979997 DOI: 10.1016/j.diff.2018.06.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2018] [Revised: 06/11/2018] [Accepted: 06/12/2018] [Indexed: 11/19/2022]
Abstract
The protein-DNA complexes that compose the end of mammalian chromosomes-telomeres-serve to stabilize linear genomic DNA and are involved in cellular and organismal aging. One mechanism that protects telomeres from premature degradation is the formation of structures called t-loops, in which the single-stranded 3' overhang present at the terminal end of telomeres loops back and invades medial double-stranded telomeric DNA. We identified looped structures formed between terminal chromosome ends and interstitial telomeric sequences (ITSs), which are found throughout the human genome, that we have termed interstitial telomeric loops (ITLs). While they form in a TRF2-dependent manner similar to t-loops, ITLs further require the physical interaction of TRF2 with the nuclear intermediate filament protein lamin A/C. Our findings suggest that interactions between telomeres and the nucleoskeleton broadly impact genomic integrity, including telomere stability, chromosome structure, and chromosome fragility. Here, we review the roles of TRF2 and lamin A/C in telomere biology and consider how their interaction may relate telomere homeostasis to cellular and organismal aging.
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Affiliation(s)
- Erica D Smith
- Department of Cell and Molecular Biology, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA
| | - Arturo G Garza-Gongora
- Department of Cell and Molecular Biology, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA
| | - Kyle L MacQuarrie
- Department of Cell and Molecular Biology, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA; Division of Hematology, Oncology and Stem Cell Transplantation, Ann & Robert H. Lurie Children's Hospital of Chicago, USA
| | - Steven T Kosak
- Department of Cell and Molecular Biology, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA.
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84
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SUN1 Regulates HIV-1 Nuclear Import in a Manner Dependent on the Interaction between the Viral Capsid and Cellular Cyclophilin A. J Virol 2018; 92:JVI.00229-18. [PMID: 29643244 DOI: 10.1128/jvi.00229-18] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2018] [Accepted: 04/04/2018] [Indexed: 12/24/2022] Open
Abstract
Human immunodeficiency virus type 1 (HIV-1) can infect nondividing cells via passing through the nuclear pore complex. The nuclear membrane-imbedded protein SUN2 was recently reported to be involved in the nuclear import of HIV-1. Whether SUN1, which shares many functional similarities with SUN2, is involved in this process remained to be explored. Here we report that overexpression of SUN1 specifically inhibited infection by HIV-1 but not that by simian immunodeficiency virus (SIV) or murine leukemia virus (MLV). Overexpression of SUN1 did not affect reverse transcription but led to reduced accumulation of the 2-long-terminal-repeat (2-LTR) circular DNA and integrated viral DNA, suggesting a block in the process of nuclear import. HIV-1 CA was mapped as a determinant for viral sensitivity to SUN1. Treatment of SUN1-expressing cells with cyclosporine (CsA) significantly reduced the sensitivity of the virus to SUN1, and an HIV-1 mutant containing CA-G89A, which does not interact with cyclophilin A (CypA), was resistant to SUN1 overexpression. Downregulation of endogenous SUN1 inhibited the nuclear entry of the wild-type virus but not that of the G89A mutant. These results indicate that SUN1 participates in the HIV-1 nuclear entry process in a manner dependent on the interaction of CA with CypA.IMPORTANCE HIV-1 infects both dividing and nondividing cells. The viral preintegration complex (PIC) can enter the nucleus through the nuclear pore complex. It has been well known that the viral protein CA plays an important role in determining the pathways by which the PIC enters the nucleus. In addition, the interaction between CA and the cellular protein CypA has been reported to be important in the selection of nuclear entry pathways, though the underlying mechanisms are not very clear. Here we show that both SUN1 overexpression and downregulation inhibited HIV-1 nuclear entry. CA played an important role in determining the sensitivity of the virus to SUN1: the regulatory activity of SUN1 toward HIV-1 relied on the interaction between CA and CypA. These results help to explain how SUN1 is involved in the HIV-1 nuclear entry process.
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85
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Linker of nucleoskeleton and cytoskeleton complex proteins in cardiomyopathy. Biophys Rev 2018; 10:1033-1051. [PMID: 29869195 PMCID: PMC6082319 DOI: 10.1007/s12551-018-0431-6] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2018] [Accepted: 05/24/2018] [Indexed: 12/21/2022] Open
Abstract
The linker of nucleoskeleton and cytoskeleton (LINC) complex couples the nuclear lamina to the cytoskeleton. The LINC complex and its associated proteins play diverse roles in cells, ranging from genome organization, nuclear morphology, gene expression, to mechanical stability. The importance of a functional LINC complex is highlighted by the large number of mutations in genes encoding LINC complex proteins that lead to skeletal and cardiac myopathies. In this review, the structure, function, and interactions between components of the LINC complex will be described. Mutations that are known to cause cardiomyopathy in patients will be discussed alongside their respective mouse models. Furthermore, future challenges for the field and emerging technologies to investigate LINC complex function will be discussed.
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86
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May CK, Carroll CW. Differential incorporation of SUN-domain proteins into LINC complexes is coupled to gene expression. PLoS One 2018; 13:e0197621. [PMID: 29813079 PMCID: PMC5973619 DOI: 10.1371/journal.pone.0197621] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2018] [Accepted: 05/05/2018] [Indexed: 11/19/2022] Open
Abstract
LInkers of Nucleoskeleton and Cytoskeleton (LINC) complexes, composed of SUN and KASH-domain proteins, span the nuclear envelope and physically connect the nuclear interior to cytoskeletal elements. Most human cells contain two SUN proteins, Sun1 and Sun2, and several KASH-proteins suggesting that multiple functionally distinct LINC complexes co-exist in the nuclear envelope. We show here, however, that while Sun1 and Sun2 in HeLa cells are each able to bind KASH-domains, Sun1 is more efficiently incorporated into LINC complexes under normal growth conditions. Furthermore, the balance of Sun1 and Sun2 incorporated into LINC complexes is cell type-specific and is correlated with SRF/Mkl1-dependent gene expression. In addition, we found that Sun1 has a LINC complex-independent role in transcriptional control, possibly by regulating the SRF/Mkl1 pathway. Together, these data reveal novel insights into the mechanisms of LINC complex regulation and demonstrate that Sun1 modulates gene expression independently of its incorporation into LINC complexes.
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Affiliation(s)
- Christopher K. May
- Dept. Of Cell Biology, Yale School of Medicine, New Haven, CT, United States of America
| | - Christopher W. Carroll
- Dept. Of Cell Biology, Yale School of Medicine, New Haven, CT, United States of America
- * E-mail:
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87
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Yang Y, Qu R, Fan T, Zhu X, Feng Y, Yang Y, Deng T, Peng Y, Huang W, Ouyang J, Dai J. Cross-talk between microtubules and the linker of nucleoskeleton complex plays a critical role in the adipogenesis of human adipose-derived stem cells. Stem Cell Res Ther 2018; 9:125. [PMID: 29720241 PMCID: PMC5930445 DOI: 10.1186/s13287-018-0836-y] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2017] [Revised: 02/26/2018] [Accepted: 03/12/2018] [Indexed: 12/28/2022] Open
Abstract
Background Adipose-derived stem cells (ASCs) that show multidifferentiation and anti-immune rejection capacities have been widely used in plastic and reconstructive surgery. Previous studies have indicated that mechanical and biophysical interactions between cells and their surrounding environment regulate essential processes, such as growth, survival, and differentiation, and the cytoskeleton system plays an important role in the mechanotransduction. However, the role of mechanical force in the determination of lineage fate is still unclear. Methods Human ASCs (hASCs) were obtained from three different donors by liposuction. Adipogenesis and osteogenesis were determined by Oil Red O and Alizarin Red staining, respectively. The mRNA levels of the cytoskeleton system, PPARγ, and C/EBPα were determined by real-time polymerase chain reaction (RT-PCR). The level of cytoskeleton, PPARγ, and C/EBPα protein levels were measured by Western blotting. The morphology of the cytoskeleton system during adipogenesis was observed with confocal microscopy. hASCs were transfected with a SUN2-specific shRNA to knockdown sun2, and a nontargeting shRNA was used as a control. Results We found that disrupting the physiological balance between the cytoskeleton and the linker of the nucleoskeleton and cytoskeleton (LINC) complex (especially SUN2) could impact the adipogenesis of hASCs in vitro. Microtubule (MT) depolymerization with nocodazole (which interferes with the polymerization of MTs) increased the expression of SUN2 and PPARγ, while taxol (an inhibitor of MT disassembly) showed the opposite results. Meanwhile, hASCs with sun2 knockdown overexpressed MTs and decreased PPARγ expression, thereby inhibiting the adipogenesis. Furthermore, knockdown of sun2 changed the structure of perinuclear MTs. Conclusions We demonstrated the presence of cross-talk between MT and SUN2, and this cross-talk plays a critical role in the rebalance of the mechanical environment and is involved in the regulation of PPARγ transport during adipogenic differentiation of hASCs. Electronic supplementary material The online version of this article (10.1186/s13287-018-0836-y) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Yiting Yang
- Department of Anatomy, Guangdong Provincial Key Laboratory of Medicine and Biomechanics, School of Basic Medical Sciences, Southern Medical University, Guangzhou, 510515, China
| | - Rongmei Qu
- Department of Anatomy, Guangdong Provincial Key Laboratory of Medicine and Biomechanics, School of Basic Medical Sciences, Southern Medical University, Guangzhou, 510515, China
| | - Tingyu Fan
- Department of Anatomy, Guangdong Provincial Key Laboratory of Medicine and Biomechanics, School of Basic Medical Sciences, Southern Medical University, Guangzhou, 510515, China
| | - Xi Zhu
- Departments of Obstetrics and Gynecology, Nanfang Hospital, Southern Medical University, Guangzhou, 510515, China
| | - Yanting Feng
- Department of Anatomy, Guangdong Provincial Key Laboratory of Medicine and Biomechanics, School of Basic Medical Sciences, Southern Medical University, Guangzhou, 510515, China
| | - Yuchao Yang
- Department of Anatomy, Guangdong Provincial Key Laboratory of Medicine and Biomechanics, School of Basic Medical Sciences, Southern Medical University, Guangzhou, 510515, China
| | - Ting Deng
- Department of Anatomy, Guangdong Provincial Key Laboratory of Medicine and Biomechanics, School of Basic Medical Sciences, Southern Medical University, Guangzhou, 510515, China
| | - Yan Peng
- Department of Anatomy, Guangdong Provincial Key Laboratory of Medicine and Biomechanics, School of Basic Medical Sciences, Southern Medical University, Guangzhou, 510515, China
| | - Wenhua Huang
- Department of Anatomy, Guangdong Provincial Key Laboratory of Medicine and Biomechanics, School of Basic Medical Sciences, Southern Medical University, Guangzhou, 510515, China.
| | - Jun Ouyang
- Department of Anatomy, Guangdong Provincial Key Laboratory of Medicine and Biomechanics, School of Basic Medical Sciences, Southern Medical University, Guangzhou, 510515, China.
| | - Jingxing Dai
- Department of Anatomy, Guangdong Provincial Key Laboratory of Medicine and Biomechanics, School of Basic Medical Sciences, Southern Medical University, Guangzhou, 510515, China.
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88
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Yang K, Adham IM, Meinhardt A, Hoyer-Fender S. Ultra-structure of the sperm head-to-tail linkage complex in the absence of the spermatid-specific LINC component SPAG4. Histochem Cell Biol 2018; 150:49-59. [PMID: 29663073 DOI: 10.1007/s00418-018-1668-7] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/10/2018] [Indexed: 12/31/2022]
Abstract
Tight connection between sperm head and tail is crucial for the transport of the male genome and fertilization. The linkage complex, the sperm head-to-tail coupling apparatus (HTCA), originates from the centrosome and anchors to the nuclear membrane. In contrast to its ultra-structural organization, which is already well known for decades, its protein composition largely still awaits future deciphering. SUN-domain proteins are essential components of a complex that links the cytoskeleton to the peripheral nucleoskeleton, which is the nuclear lamina. Here, we studied the impact of the SUN protein SPAG4/SUN4 on the formation of the HTCA. SPAG4/SUN4 is specifically expressed in haploid male germ cells showing a polarized distribution towards the posterior pole in late spermatids that corresponds to the tail attachment site. SPAG4-deficient male mice are infertile with compromised manchette formation and malformed sperm heads. Nonetheless, sperm tails are present demonstrating dispensability of a proper manchette for their formation. Ultra-structural analyses revealed that the development of the sperm head-to-tail linkage complex in the absence of SPAG4 resembles that in the wild type. However, in SPAG4-deficient sperm, the attachment site is diminished with obvious lateral detachment of the HTCA from the nucleus. Our results thus indicate that SPAG4, albeit not essential for the formation of the HTCA per se, is, nevertheless, required for tightening the sperm head-to-tail anchorage by provoking the correct attachment of the lateral parts of the basal plate to the implantation fossa.
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Affiliation(s)
- Kefei Yang
- Department of Developmental Biology, Johann-Friedrich-Blumenbach-Institute of Zoology and Anthropology, GZMB, Ernst-Caspari-Haus, Georg-August-Universität Göttingen, Justus-von-Liebig-Weg 11, Göttingen, Germany
| | - Ibrahim M Adham
- Department of Human Genetics, University Medicine, Georg-August-Universität Göttingen, Heinrich-Düker-Weg 12, Göttingen, Germany
| | - Andreas Meinhardt
- Department of Anatomy and Cell Biology, Justus-Liebig-University Giessen, Aulweg 123, Giessen, Germany
| | - Sigrid Hoyer-Fender
- Department of Developmental Biology, Johann-Friedrich-Blumenbach-Institute of Zoology and Anthropology, GZMB, Ernst-Caspari-Haus, Georg-August-Universität Göttingen, Justus-von-Liebig-Weg 11, Göttingen, Germany.
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89
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Potter C, Razafsky D, Wozniak D, Casey M, Penrose S, Ge X, Mahjoub MR, Hodzic D. The KASH-containing isoform of Nesprin1 giant associates with ciliary rootlets of ependymal cells. Neurobiol Dis 2018; 115:82-91. [PMID: 29630990 DOI: 10.1016/j.nbd.2018.04.006] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2017] [Revised: 02/25/2018] [Accepted: 04/04/2018] [Indexed: 12/14/2022] Open
Abstract
Biallelic nonsense mutations of SYNE1 underlie a variable array of cerebellar and non-cerebellar pathologies of unknown molecular etiology. SYNE1 encodes multiple isoforms of Nesprin1 that associate with the nuclear envelope, with large cerebellar synapses and with ciliary rootlets of photoreceptors. Using two novel mouse models, we determined the expression pattern of Nesprin1 isoforms in the cerebellum whose integrity and functions are invariably affected by SYNE1 mutations. We further show that a giant isoform of Nesprin1 associates with the ciliary rootlets of ependymal cells that line brain ventricles and establish that this giant ciliary isoform of Nesprin1 harbors a KASH domain. Whereas cerebellar phenotypes are not recapitulated in Nes1gSTOP/STOP mice, these mice display a significant increase of ventricular volume. Together, these data fuel novel hypotheses about the molecular pathogenesis of SYNE1 mutations and support that KASH proteins may localize beyond the nuclear envelope in vivo.
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Affiliation(s)
- C Potter
- Department of Developmental Biology, Washington University School of Medicine, 660 S. Euclid Ave, St Louis, MO 63110, USA
| | - D Razafsky
- Department of Developmental Biology, Washington University School of Medicine, 660 S. Euclid Ave, St Louis, MO 63110, USA
| | - D Wozniak
- Department of Psychiatry, Washington University School of Medicine, 660 S. Euclid Ave, St Louis, MO 63110, USA
| | - M Casey
- Department of Developmental Biology, Washington University School of Medicine, 660 S. Euclid Ave, St Louis, MO 63110, USA
| | - S Penrose
- Department of Developmental Biology, Washington University School of Medicine, 660 S. Euclid Ave, St Louis, MO 63110, USA
| | - X Ge
- Department of Radiology, Washington University School of Medicine, 660 S. Euclid Ave, St Louis, MO 63110, USA
| | - M R Mahjoub
- Department of Medicine, Washington University School of Medicine, 660 S. Euclid Ave, St Louis, MO 63110, USA
| | - D Hodzic
- Department of Developmental Biology, Washington University School of Medicine, 660 S. Euclid Ave, St Louis, MO 63110, USA.
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90
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Muncie JM, Weaver VM. The Physical and Biochemical Properties of the Extracellular Matrix Regulate Cell Fate. Curr Top Dev Biol 2018; 130:1-37. [PMID: 29853174 DOI: 10.1016/bs.ctdb.2018.02.002] [Citation(s) in RCA: 188] [Impact Index Per Article: 26.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
The extracellular matrix is a complex network of hydrated macromolecular proteins and sugars that, in concert with bound soluble factors, comprise the acellular stromal microenvironment of tissues. Rather than merely providing structural information to cells, the extracellular matrix plays an instructive role in development and is critical for the maintenance of tissue homeostasis. In this chapter, we review the composition of the extracellular matrix and summarize data illustrating its importance in embryogenesis, tissue-specific development, and stem cell differentiation. We discuss how the biophysical and biochemical properties of the extracellular matrix ligate specific transmembrane receptors to activate intracellular signaling that alter cell shape and cytoskeletal dynamics to modulate cell growth and viability, and direct cell migration and cell fate. We present examples describing how the extracellular matrix functions as a highly complex physical and chemical entity that regulates tissue organization and cell behavior through a dynamic and reciprocal dialogue with the cellular constituents of the tissue. We suggest that the extracellular matrix not only transmits cellular and tissue-level force to shape development and tune cellular activities that are key for coordinated tissue behavior, but that it is itself remodeled such that it temporally evolves to maintain the integrated function of the tissue. Accordingly, we argue that perturbations in extracellular matrix composition and structure compromise key developmental events and tissue homeostasis, and promote disease.
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Affiliation(s)
- Jonathon M Muncie
- Center for Bioengineering and Tissue Regeneration, University of California, San Francisco, CA, United States; Graduate Program in Bioengineering, University of California San Francisco and University of California Berkeley, San Francisco, CA, United States
| | - Valerie M Weaver
- Center for Bioengineering and Tissue Regeneration, University of California, San Francisco, CA, United States; Eli and Edythe Broad Center of Regeneration Medicine and Stem Cell Research, The Helen Diller Family Comprehensive Cancer Center, University of California, San Francisco, CA, United States.
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91
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Graham DM, Andersen T, Sharek L, Uzer G, Rothenberg K, Hoffman BD, Rubin J, Balland M, Bear JE, Burridge K. Enucleated cells reveal differential roles of the nucleus in cell migration, polarity, and mechanotransduction. J Cell Biol 2018; 217:895-914. [PMID: 29351995 PMCID: PMC5839789 DOI: 10.1083/jcb.201706097] [Citation(s) in RCA: 84] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2017] [Revised: 11/16/2017] [Accepted: 12/14/2017] [Indexed: 01/11/2023] Open
Abstract
The nucleus has long been postulated to play a critical physical role during cell polarization and migration, but that role has not been defined or rigorously tested. Here, we enucleated cells to test the physical necessity of the nucleus during cell polarization and directed migration. Using enucleated mammalian cells (cytoplasts), we found that polarity establishment and cell migration in one dimension (1D) and two dimensions (2D) occur without the nucleus. Cytoplasts directionally migrate toward soluble (chemotaxis) and surface-bound (haptotaxis) extracellular cues and migrate collectively in scratch-wound assays. Consistent with previous studies, migration in 3D environments was dependent on the nucleus. In part, this likely reflects the decreased force exerted by cytoplasts on mechanically compliant substrates. This response is mimicked both in cells with nucleocytoskeletal defects and upon inhibition of actomyosin-based contractility. Together, our observations reveal that the nucleus is dispensable for polarization and migration in 1D and 2D but critical for proper cell mechanical responses.
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Affiliation(s)
- David M Graham
- Department of Cell Biology and Physiology, University of North Carolina at Chapel Hill, Chapel Hill, NC
- UNC Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC
| | - Tomas Andersen
- Laboratoire Interdisciplinaire de Physique, Université Grenoble Alpes, Grenoble, France
| | - Lisa Sharek
- Department of Cell Biology and Physiology, University of North Carolina at Chapel Hill, Chapel Hill, NC
| | - Gunes Uzer
- Department of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC
- Department of Mechanical and Biomedical Engineering, Boise State University, Boise, ID
| | | | | | - Janet Rubin
- Department of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC
| | - Martial Balland
- Laboratoire Interdisciplinaire de Physique, Université Grenoble Alpes, Grenoble, France
| | - James E Bear
- Department of Cell Biology and Physiology, University of North Carolina at Chapel Hill, Chapel Hill, NC
- UNC Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC
| | - Keith Burridge
- Department of Cell Biology and Physiology, University of North Carolina at Chapel Hill, Chapel Hill, NC
- UNC Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC
- McAllister Heart Institute, University of North Carolina at Chapel Hill, Chapel Hill, NC
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92
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Stroud MJ, Fang X, Zhang J, Guimarães-Camboa N, Veevers J, Dalton ND, Gu Y, Bradford WH, Peterson KL, Evans SM, Gerace L, Chen J. Luma is not essential for murine cardiac development and function. Cardiovasc Res 2018; 114:378-388. [PMID: 29040414 PMCID: PMC6019056 DOI: 10.1093/cvr/cvx205] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/19/2017] [Accepted: 10/11/2017] [Indexed: 12/13/2022] Open
Abstract
AIMS Luma is a recently discovered, evolutionarily conserved protein expressed in mammalian heart, which is associated with the LInker of Nucleoskeleton and Cytoskeleton (LINC) complex. The LINC complex structurally integrates the nucleus and the cytoplasm and plays a critical role in mechanotransduction across the nuclear envelope. Mutations in several LINC components in both humans and mice result in various cardiomyopathies, implying they play essential, non-redundant roles. A single amino acid substitution of serine 358 to leucine (S358L) in Luma is the unequivocal cause of a distinct form of arrhythmogenic cardiomyopathy. However, the role of Luma in heart has remained obscure. In addition, it also remains to be determined how the S358L mutation in Luma leads to cardiomyopathy. METHODS AND RESULTS To determine the role of Luma in the heart, we first determined the expression pattern of Luma in mouse heart. Luma was sporadically expressed in cardiomyocytes throughout the heart, but was highly and uniformly expressed in cardiac fibroblasts and vascular smooth muscle cells. We also generated germline null Luma mice and discovered that germline null mutants were viable and exhibited normal cardiac function. Luma null mice also responded normally to pressure overload induced by transverse aortic constriction. In addition, localization and expression of other LINC complex components in both cardiac myocytes and fibroblasts was unaffected by global loss of Luma. Furthermore, we also generated and characterized Luma S358L knock-in mice, which displayed normal cardiac function and morphology. CONCLUSION Our data suggest that Luma is dispensable for murine cardiac development and function and that the Luma S358L mutation alone may not cause cardiomyopathy in mice.
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MESH Headings
- Animals
- Arrhythmogenic Right Ventricular Dysplasia/genetics
- Arrhythmogenic Right Ventricular Dysplasia/metabolism
- Cells, Cultured
- Cytoskeleton/metabolism
- Female
- Fibroblasts/metabolism
- Gene Expression Regulation, Developmental
- Genetic Predisposition to Disease
- Heart/embryology
- Heart/physiopathology
- Humans
- Hypertrophy, Left Ventricular/genetics
- Hypertrophy, Left Ventricular/metabolism
- Hypertrophy, Left Ventricular/physiopathology
- Male
- Mechanotransduction, Cellular
- Membrane Proteins/genetics
- Membrane Proteins/metabolism
- Mice, Inbred C57BL
- Mice, Knockout
- Morphogenesis
- Myocardium/metabolism
- Myocardium/pathology
- Myocytes, Cardiac/metabolism
- Myocytes, Smooth Muscle/metabolism
- Nuclear Matrix/metabolism
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Affiliation(s)
- Matthew J Stroud
- Department of Medicine, University of California San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA
| | - Xi Fang
- Department of Medicine, University of California San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA
| | - Jianlin Zhang
- Department of Medicine, University of California San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA
| | - Nuno Guimarães-Camboa
- Department of Pharmacology, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California San Diego, La Jolla, CA 92093, USA
| | - Jennifer Veevers
- Department of Medicine, University of California San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA
| | - Nancy D Dalton
- Department of Medicine, University of California San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA
| | - Yusu Gu
- Department of Medicine, University of California San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA
| | - William H Bradford
- Department of Medicine, University of California San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA
| | - Kirk L Peterson
- Department of Medicine, University of California San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA
| | - Sylvia M Evans
- Department of Pharmacology, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California San Diego, La Jolla, CA 92093, USA
| | - Larry Gerace
- Department of Cell and Molecular Biology, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Ju Chen
- Department of Medicine, University of California San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA
- Corresponding author. Tel: 858 822 4276; fax: 858 822 3027, E-mail:
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93
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Bhargava A, Lahaye X, Manel N. Let me in: Control of HIV nuclear entry at the nuclear envelope. Cytokine Growth Factor Rev 2018. [PMID: 29526438 DOI: 10.1016/j.cytogfr.2018.02.006] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
The nuclear envelope is a physical barrier that isolates the cellular DNA from the rest of the cell, thereby limiting pathogen invasion. The Human Immunodeficiency Virus (HIV) has a remarkable ability to enter the nucleus of non-dividing target cells such as lymphocytes, macrophages and dendritic cells. While this step is critical for replication of the virus, it remains one of the less understood aspects of HIV infection. Here, we review the viral and host factors that favor or inhibit HIV entry into the nucleus, including the viral capsid, integrase, the central viral DNA flap, and the host proteins CPSF6, TNPO3, Nucleoporins, SUN1, SUN2, Cyclophilin A and MX2. We review recent perspectives on the mechanism of action of these factors, and formulate fundamental questions that remain. Overall, these findings deepen our understanding of HIV nuclear import and strengthen the favorable position of nuclear HIV entry for antiviral targeting.
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Affiliation(s)
- Anvita Bhargava
- Immunity and Cancer Department, Institut Curie, PSL Research University, INSERM U932, 75005 Paris, France
| | - Xavier Lahaye
- Immunity and Cancer Department, Institut Curie, PSL Research University, INSERM U932, 75005 Paris, France
| | - Nicolas Manel
- Immunity and Cancer Department, Institut Curie, PSL Research University, INSERM U932, 75005 Paris, France.
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94
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Nesprin-2 Interacts with Condensin Component SMC2. Int J Cell Biol 2018; 2017:8607532. [PMID: 29445399 PMCID: PMC5763115 DOI: 10.1155/2017/8607532] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2017] [Revised: 11/17/2017] [Accepted: 12/07/2017] [Indexed: 01/24/2023] Open
Abstract
The nuclear envelope proteins, Nesprins, have been primarily studied during interphase where they function in maintaining nuclear shape, size, and positioning. We analyze here the function of Nesprin-2 in chromatin interactions in interphase and dividing cells. We characterize a region in the rod domain of Nesprin-2 that is predicted as SMC domain (aa 1436-1766). We show that this domain can interact with itself. It furthermore has the capacity to bind to SMC2 and SMC4, the core subunits of condensin. The interaction was observed during all phases of the cell cycle; it was particularly strong during S phase and persisted also during mitosis. Nesprin-2 knockdown did not affect condensin distribution; however we noticed significantly higher numbers of chromatin bridges in Nesprin-2 knockdown cells in anaphase. Thus, Nesprin-2 may have an impact on chromosomes which might be due to its interaction with condensins or to indirect mechanisms provided by its interactions at the nuclear envelope.
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95
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Xu Y, Li W, Ke H, Feng W. Structural conservation of the autoinhibitory domain in SUN proteins. Biochem Biophys Res Commun 2018; 496:1337-1343. [DOI: 10.1016/j.bbrc.2018.02.015] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2018] [Accepted: 02/02/2018] [Indexed: 10/18/2022]
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96
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Tschumperlin DJ, Ligresti G, Hilscher MB, Shah VH. Mechanosensing and fibrosis. J Clin Invest 2018; 128:74-84. [PMID: 29293092 DOI: 10.1172/jci93561] [Citation(s) in RCA: 201] [Impact Index Per Article: 28.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Tissue injury disrupts the mechanical homeostasis that underlies normal tissue architecture and function. The failure to resolve injury and restore homeostasis gives rise to progressive fibrosis that is accompanied by persistent alterations in the mechanical environment as a consequence of pathological matrix deposition and stiffening. This Review focuses on our rapidly growing understanding of the molecular mechanisms linking the altered mechanical environment in injury, repair, and fibrosis to cellular activation. In particular, our focus is on the mechanisms by which cells transduce mechanical signals, leading to transcriptional and epigenetic responses that underlie both transient and persistent alterations in cell state that contribute to fibrosis. Translation of these mechanobiological insights may enable new approaches to promote tissue repair and arrest or reverse fibrotic tissue remodeling.
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Affiliation(s)
| | | | - Moira B Hilscher
- Division of Gastroenterology and Hepatology, Mayo Clinic, Rochester, Minnesota, USA
| | - Vijay H Shah
- Division of Gastroenterology and Hepatology, Mayo Clinic, Rochester, Minnesota, USA
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97
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Burke B. Interactions of Nesprin-4-Containing LINC Complexes in Outer Hair Cells Explored by BioID. Methods Mol Biol 2018; 1840:45-56. [PMID: 30141037 DOI: 10.1007/978-1-4939-8691-0_5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
As components of diverse tissues and organs, metazoan cells have to display a wide variety of specialized functions. Implementation of such functions invariably entails the establishment of tissue-specific cellular architecture (Bone and Starr, J Cell Sci 129:1951-1961, 2016). In animal cells, the nucleus is typically the largest organelle and in many respects acts as a landmark for multiple subcellular structures. For instance, in epithelial cells, the nucleus is frequently positioned close to the basal membrane via association with the cytoskeleton. Clearly such associations must be mediated by protein components of the outer nuclear membrane. One such protein is Nesprin-4, a member of the KASH domain family that is expressed in a variety of epithelial cells, including sensory outer hair cells of the inner ear. In this chapter, I describe a proximity-based biotinylation technique, BioID, that can be applied to Nesprin-4 to map its interactions at the nuclear periphery.
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Affiliation(s)
- Brian Burke
- Institute of Medical Biology, 8A Biomedical Drive, Singapore, 138648, Singapore.
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98
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Houthaeve G, Robijns J, Braeckmans K, De Vos WH. Bypassing Border Control: Nuclear Envelope Rupture in Disease. Physiology (Bethesda) 2018; 33:39-49. [DOI: 10.1152/physiol.00029.2017] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2017] [Revised: 10/31/2017] [Accepted: 10/31/2017] [Indexed: 11/22/2022] Open
Abstract
Recent observations in laminopathy patient cells and cancer cells have revealed that the nuclear envelope (NE) can transiently rupture during interphase. NE rupture leads to an uncoordinated exchange of nuclear and cytoplasmic material, thereby deregulating cellular homeostasis. Moreover, concurrently inflicted DNA damage could prime rupture-prone cells for genome instability. Thus, NE rupture may represent a novel pathogenic mechanism that has far-reaching consequences for cell and organism physiology.
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Affiliation(s)
- Gaëlle Houthaeve
- Department of Veterinary Sciences, Laboratory of Cell Biology and Histology, University of Antwerp, Antwerp, Belgium
- Laboratory of General Biochemistry and Physical Pharmacy, Ghent University, Ghent, Belgium
| | - Joke Robijns
- Department of Veterinary Sciences, Laboratory of Cell Biology and Histology, University of Antwerp, Antwerp, Belgium
| | - Kevin Braeckmans
- Laboratory of General Biochemistry and Physical Pharmacy, Ghent University, Ghent, Belgium
- Centre for Nano- and Biophotonics, Ghent University, Ghent, Belgium
| | - Winnok H. De Vos
- Department of Veterinary Sciences, Laboratory of Cell Biology and Histology, University of Antwerp, Antwerp, Belgium
- Department of Molecular Biotechnology, Cell Systems and Imaging Research Group (CSI), Ghent University, Ghent, Belgium
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Li EW, McKee-Muir OC, Gilbert PM. Cellular Biomechanics in Skeletal Muscle Regeneration. Curr Top Dev Biol 2018; 126:125-176. [DOI: 10.1016/bs.ctdb.2017.08.007] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Majumder S, Willey PT, DeNies MS, Liu AP, Luxton GWG. A synthetic biology platform for the reconstitution and mechanistic dissection of LINC complex assembly. J Cell Sci 2018; 132:jcs.219451. [DOI: 10.1242/jcs.219451] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2018] [Accepted: 09/19/2018] [Indexed: 11/20/2022] Open
Abstract
The linker of nucleoskeleton and cytoskeleton (LINC) is a conserved nuclear envelope-spanning molecular bridge that is responsible for the mechanical integration of the nucleus with the cytoskeleton. LINC complexes are formed by a transluminal interaction between the outer and inner nuclear membrane KASH and SUN proteins, respectively. Despite recent structural insights, our mechanistic understanding of LINC complex assembly remains limited by the lack of an experimental system for its in vitro reconstitution and manipulation. Here, we describe artificial nuclear membranes (ANMs) as a synthetic biology platform based on mammalian cell-free expression for the rapid reconstitution of SUN proteins in supported lipid bilayers. We demonstrate that SUN1 and SUN2 are oriented in ANMs with solvent-exposed C-terminal KASH-binding SUN domains. We also find that SUN2 possesses a single transmembrane domain, while SUN1 possesses three. Finally, SUN protein-containing ANMs bind synthetic KASH peptides, thereby reconstituting the LINC complex core. This work represents the first in vitro reconstitution of KASH-binding SUN proteins in supported lipid bilayers using cell-free expression, which will be invaluable for testing proposed models of LINC complex assembly and its regulation.
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Affiliation(s)
- Sagardip Majumder
- Department of Mechanical Engineering, University of Michigan, Ann Arbor, MI, 48019, USA
| | - Patrick T. Willey
- Department of Genetics, Cell Biology, and Development, University of Minnesota, Minneapolis, MN 55455, USA
| | - Maxwell S. DeNies
- Cellular and Molecular Biology Program, University of Michigan, Ann Arbor, MI, 48019, USA
| | - Allen P. Liu
- Department of Mechanical Engineering, University of Michigan, Ann Arbor, MI, 48019, USA
- Cellular and Molecular Biology Program, University of Michigan, Ann Arbor, MI, 48019, USA
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, 48019, USA
- Biophysics Program, University of Michigan, Ann Arbor, MI, 48019, USA
| | - G. W. Gant Luxton
- Department of Genetics, Cell Biology, and Development, University of Minnesota, Minneapolis, MN 55455, USA
- Department of Biomedical Engineering, University of Minnesota, Minneapolis, MN 55455, USA
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