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Zi-Yi Z, Qin Q, Fei Z, Cun-Yu C, Lin T. Nesprin proteins: bridging nuclear envelope dynamics to muscular dysfunction. Cell Commun Signal 2024; 22:208. [PMID: 38566066 PMCID: PMC10986154 DOI: 10.1186/s12964-024-01593-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2024] [Accepted: 03/24/2024] [Indexed: 04/04/2024] Open
Abstract
This review presents a comprehensive exploration of the pivotal role played by the Linker of Nucleoskeleton and Cytoskeleton (LINC) complex, with a particular focus on Nesprin proteins, in cellular mechanics and the pathogenesis of muscular diseases. Distinguishing itself from prior works, the analysis delves deeply into the intricate interplay of the LINC complex, emphasizing its indispensable contribution to maintaining cellular structural integrity, especially in mechanically sensitive tissues such as cardiac and striated muscles. Additionally, the significant association between mutations in Nesprin proteins and the onset of Dilated Cardiomyopathy (DCM) and Emery-Dreifuss Muscular Dystrophy (EDMD) is highlighted, underscoring their pivotal role in disease pathogenesis. Through a comprehensive examination of DCM and EDMD cases, the review elucidates the disruptions in the LINC complex, nuclear morphology alterations, and muscular developmental disorders, thus emphasizing the essential function of an intact LINC complex in preserving muscle physiological functions. Moreover, the review provides novel insights into the implications of Nesprin mutations for cellular dynamics in the pathogenesis of muscular diseases, particularly in maintaining cardiac structural and functional integrity. Furthermore, advanced therapeutic strategies, including rectifying Nesprin gene mutations, controlling Nesprin protein expression, enhancing LINC complex functionality, and augmenting cardiac muscle cell function are proposed. By shedding light on the intricate molecular mechanisms underlying nuclear-cytoskeletal interactions, the review lays the groundwork for future research and therapeutic interventions aimed at addressing genetic muscle disorders.
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Affiliation(s)
- Zhou Zi-Yi
- Department of Cardiology, Yichang Central People's Hospital, Yichang, 443003, Hubei, People's Republic of China
- School of Basic Medicine, China Three Gorges University, Yichang, 443000, Hubei, People's Republic of China
| | - Qin Qin
- Department of Cardiology, Yichang Central People's Hospital, Yichang, 443003, Hubei, People's Republic of China
- School of Basic Medicine, China Three Gorges University, Yichang, 443000, Hubei, People's Republic of China
| | - Zhou Fei
- Department of Cardiology, Yichang Central People's Hospital, Yichang, 443003, Hubei, People's Republic of China
| | - Cao Cun-Yu
- School of Basic Medicine, China Three Gorges University, Yichang, 443000, Hubei, People's Republic of China
- College of Basic Medical Sciences, Hubei Key Laboratory of Tumor Microencironment and immunotherapy, China Three Gorges University, Yichang, 443000, Hubei, People's Republic of China
| | - Teng Lin
- Department of Cardiology, Yichang Central People's Hospital, Yichang, 443003, Hubei, People's Republic of China.
- King's College London British Heart Foundation Centre of Research Excellence, School of Cardiovascular and Metabolic Medicine & Sciences, London, SE5 9NU, UK.
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2
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De Silva S, Fan Z, Kang B, Shanahan CM, Zhang Q. Nesprin-1: novel regulator of striated muscle nuclear positioning and mechanotransduction. Biochem Soc Trans 2023; 51:1331-1345. [PMID: 37171063 PMCID: PMC10317153 DOI: 10.1042/bst20221541] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2022] [Revised: 04/20/2023] [Accepted: 04/20/2023] [Indexed: 05/13/2023]
Abstract
Nesprins (nuclear envelope spectrin repeat proteins) are multi-isomeric scaffolding proteins. Giant nesprin-1 and -2 localise to the outer nuclear membrane, interact with SUN (Sad1p/UNC-84) domain-containing proteins at the inner nuclear membrane to form the LInker of Nucleoskeleton and Cytoskeleton (LINC) complex, which, in association with lamin A/C and emerin, mechanically couples the nucleus to the cytoskeleton. Despite ubiquitous expression of nesprin giant isoforms, pathogenic mutations in nesprin-1 and -2 are associated with tissue-specific disorders, particularly related to striated muscle such as dilated cardiomyopathy and Emery-Dreifuss muscular dystrophy. Recent evidence suggests this muscle-specificity might be attributable in part, to the small muscle specific isoform, nesprin-1α2, which has a novel role in striated muscle function. Our current understanding of muscle-specific functions of nesprin-1 and its isoforms will be summarised in this review to provide insight into potential pathological mechanisms of nesprin-related muscle disease and may inform potential targets of therapeutic modulation.
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Affiliation(s)
- Shanelle De Silva
- King's College London British Heart Foundation Centre of Research Excellence, School of Cardiovascular and Metabolic Medicine & Sciences, London SE5 9NU, U.K
| | - Zhijuan Fan
- King's College London British Heart Foundation Centre of Research Excellence, School of Cardiovascular and Metabolic Medicine & Sciences, London SE5 9NU, U.K
- Clinical Laboratory, Tianjin Third Central Hospital, Tianjin 300170, China
| | - Baoqiang Kang
- King's College London British Heart Foundation Centre of Research Excellence, School of Cardiovascular and Metabolic Medicine & Sciences, London SE5 9NU, U.K
| | - Catherine M. Shanahan
- King's College London British Heart Foundation Centre of Research Excellence, School of Cardiovascular and Metabolic Medicine & Sciences, London SE5 9NU, U.K
| | - Qiuping Zhang
- King's College London British Heart Foundation Centre of Research Excellence, School of Cardiovascular and Metabolic Medicine & Sciences, London SE5 9NU, U.K
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3
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Leong EL, Khaing NT, Cadot B, Hong WL, Kozlov S, Werner H, Wong ESM, Stewart CL, Burke B, Lee YL. Nesprin-1 LINC complexes recruit microtubule cytoskeleton proteins and drive pathology in Lmna-mutant striated muscle. Hum Mol Genet 2022; 32:177-191. [PMID: 35925868 PMCID: PMC9840208 DOI: 10.1093/hmg/ddac179] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2021] [Revised: 07/27/2022] [Accepted: 07/29/2022] [Indexed: 01/19/2023] Open
Abstract
Mutations in LMNA, the gene encoding A-type lamins, cause laminopathies-diseases of striated muscle and other tissues. The aetiology of laminopathies has been attributed to perturbation of chromatin organization or structural weakening of the nuclear envelope (NE) such that the nucleus becomes more prone to mechanical damage. The latter model requires a conduit for force transmission to the nucleus. NE-associated Linker of Nucleoskeleton and Cytoskeleton (LINC) complexes are one such pathway. Using clustered regularly interspaced short palindromic repeats to disrupt the Nesprin-1 KASH (Klarsicht, ANC-1, Syne Homology) domain, we identified this LINC complex protein as the predominant NE anchor for microtubule cytoskeleton components, including nucleation activities and motor complexes, in mouse cardiomyocytes. Loss of Nesprin-1 LINC complexes resulted in loss of microtubule cytoskeleton proteins at the nucleus and changes in nuclear morphology and positioning in striated muscle cells, but with no overt physiological defects. Disrupting the KASH domain of Nesprin-1 suppresses Lmna-linked cardiac pathology, likely by reducing microtubule cytoskeleton activities at the nucleus. Nesprin-1 LINC complexes thus represent a potential therapeutic target for striated muscle laminopathies.
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Affiliation(s)
| | | | - Bruno Cadot
- Sorbonne Université, INSERM U974, Institut de Myologie, GH Pitié Salpêtrière, 47 Boulevard de l’Hôpital, Paris 75013, France
| | - Wei Liang Hong
- Institute of Medical Biology, Agency for Science Technology and Research (ASTAR), 8A Biomedical Grove, Level 6 Immunos, Singapore 138648, Singapore,ASTAR Skin Research Labs (ASRL), Agency for Science Technology and Research (ASTAR), 8A Biomedical Grove, Level 6 Immunos, Singapore 138648, Singapore
| | - Serguei Kozlov
- Center for Advanced Preclinical Research, Frederick National Laboratory for Cancer Research, Frederick, MD 21702, USA
| | - Hendrikje Werner
- Institute of Medical Biology, Agency for Science Technology and Research (ASTAR), 8A Biomedical Grove, Level 6 Immunos, Singapore 138648, Singapore,ASTAR Skin Research Labs (ASRL), Agency for Science Technology and Research (ASTAR), 8A Biomedical Grove, Level 6 Immunos, Singapore 138648, Singapore
| | - Esther Sook Miin Wong
- Institute of Medical Biology, Agency for Science Technology and Research (ASTAR), 8A Biomedical Grove, Level 6 Immunos, Singapore 138648, Singapore,Institute of Molecular and Cell Biology, Agency for Science, Technology and Research (ASTAR), 8A Biomedical Grove, Level 5 Immunos, Singapore 138648, Singapore
| | - Colin L Stewart
- To whom correspondence should be addressed. Colin L. Stewart, ; Brian Burke, ; Yin Loon Lee,
| | - Brian Burke
- To whom correspondence should be addressed. Colin L. Stewart, ; Brian Burke, ; Yin Loon Lee,
| | - Yin Loon Lee
- To whom correspondence should be addressed. Colin L. Stewart, ; Brian Burke, ; Yin Loon Lee,
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4
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Becker R, Vergarajauregui S, Billing F, Sharkova M, Lippolis E, Mamchaoui K, Ferrazzi F, Engel FB. Myogenin controls via AKAP6 non-centrosomal microtubule-organizing center formation at the nuclear envelope. eLife 2021; 10:65672. [PMID: 34605406 PMCID: PMC8523159 DOI: 10.7554/elife.65672] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2020] [Accepted: 10/01/2021] [Indexed: 12/22/2022] Open
Abstract
Non-centrosomal microtubule-organizing centers (MTOCs) are pivotal for the function of multiple cell types, but the processes initiating their formation are unknown. Here, we find that the transcription factor myogenin is required in murine myoblasts for the localization of MTOC proteins to the nuclear envelope. Moreover, myogenin is sufficient in fibroblasts for nuclear envelope MTOC (NE-MTOC) formation and centrosome attenuation. Bioinformatics combined with loss- and gain-of-function experiments identified induction of AKAP6 expression as one central mechanism for myogenin-mediated NE-MTOC formation. Promoter studies indicate that myogenin preferentially induces the transcription of muscle- and NE-MTOC-specific isoforms of Akap6 and Syne1, which encodes nesprin-1α, the NE-MTOC anchor protein in muscle cells. Overexpression of AKAP6β and nesprin-1α was sufficient to recruit endogenous MTOC proteins to the nuclear envelope of myoblasts in the absence of myogenin. Taken together, our results illuminate how mammals transcriptionally control the switch from a centrosomal MTOC to an NE-MTOC and identify AKAP6 as a novel NE-MTOC component in muscle cells.
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Affiliation(s)
- Robert Becker
- Experimental Renal and Cardiovascular Research, Department of Nephropathology, Institute of Pathology, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Erlangen, Germany
| | - Silvia Vergarajauregui
- Experimental Renal and Cardiovascular Research, Department of Nephropathology, Institute of Pathology, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Erlangen, Germany
| | - Florian Billing
- Experimental Renal and Cardiovascular Research, Department of Nephropathology, Institute of Pathology, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Erlangen, Germany
| | - Maria Sharkova
- Experimental Renal and Cardiovascular Research, Department of Nephropathology, Institute of Pathology, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Erlangen, Germany
| | - Eleonora Lippolis
- Institute of Human Genetics, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
| | - Kamel Mamchaoui
- Sorbonne Universités UPMC Université Paris 06, INSERM U974, CNRS FRE3617, Center for Research in Myology, GH Pitié Salpêtrière, 47 Boulevard de l'Hôpital, Paris, France
| | - Fulvia Ferrazzi
- Institute of Human Genetics, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany.,Department of Nephropathology, Institute of Pathology, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Erlangen, Germany.,Institute of Pathology, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Erlangen, Germany
| | - Felix B Engel
- Experimental Renal and Cardiovascular Research, Department of Nephropathology, Institute of Pathology, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Erlangen, Germany.,Muscle Research Center Erlangen (MURCE), Erlangen, Germany
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5
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Hao H, Kalra S, Jameson LE, Guerrero LA, Cain NE, Bolivar J, Starr DA. The Nesprin-1/-2 ortholog ANC-1 regulates organelle positioning in C. elegans independently from its KASH or actin-binding domains. eLife 2021; 10:e61069. [PMID: 33860766 PMCID: PMC8139857 DOI: 10.7554/elife.61069] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2020] [Accepted: 04/11/2021] [Indexed: 12/15/2022] Open
Abstract
KASH proteins in the outer nuclear membrane comprise the cytoplasmic half of linker of nucleoskeleton and cytoskeleton (LINC) complexes that connect nuclei to the cytoskeleton. Caenorhabditis elegans ANC-1, an ortholog of Nesprin-1/2, contains actin-binding and KASH domains at opposite ends of a long spectrin-like region. Deletion of either the KASH or calponin homology (CH) domains does not completely disrupt nuclear positioning, suggesting neither KASH nor CH domains are essential. Deletions in the spectrin-like region of ANC-1 led to significant defects, but only recapitulated the null phenotype in combination with mutations in the transmembrane (TM) span. In anc-1 mutants, the endoplasmic reticulum ER, mitochondria, and lipid droplets were unanchored, moving throughout the cytoplasm. The data presented here support a cytoplasmic integrity model where ANC-1 localizes to the ER membrane and extends into the cytoplasm to position nuclei, ER, mitochondria, and other organelles in place.
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Affiliation(s)
- Hongyan Hao
- Department of Molecular and Cellular Biology, University of California, DavisDavisUnited States
| | - Shilpi Kalra
- Department of Molecular and Cellular Biology, University of California, DavisDavisUnited States
| | - Laura E Jameson
- Department of Molecular and Cellular Biology, University of California, DavisDavisUnited States
| | - Leslie A Guerrero
- Department of Molecular and Cellular Biology, University of California, DavisDavisUnited States
| | - Natalie E Cain
- Department of Molecular and Cellular Biology, University of California, DavisDavisUnited States
| | - Jessica Bolivar
- Department of Molecular and Cellular Biology, University of California, DavisDavisUnited States
| | - Daniel A Starr
- Department of Molecular and Cellular Biology, University of California, DavisDavisUnited States
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Jabre S, Hleihel W, Coirault C. Nuclear Mechanotransduction in Skeletal Muscle. Cells 2021; 10:cells10020318. [PMID: 33557157 PMCID: PMC7913907 DOI: 10.3390/cells10020318] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2020] [Revised: 01/29/2021] [Accepted: 02/01/2021] [Indexed: 12/11/2022] Open
Abstract
Skeletal muscle is composed of multinucleated, mature muscle cells (myofibers) responsible for contraction, and a resident pool of mononucleated muscle cell precursors (MCPs), that are maintained in a quiescent state in homeostatic conditions. Skeletal muscle is remarkable in its ability to adapt to mechanical constraints, a property referred as muscle plasticity and mediated by both MCPs and myofibers. An emerging body of literature supports the notion that muscle plasticity is critically dependent upon nuclear mechanotransduction, which is transduction of exterior physical forces into the nucleus to generate a biological response. Mechanical loading induces nuclear deformation, changes in the nuclear lamina organization, chromatin condensation state, and cell signaling, which ultimately impacts myogenic cell fate decisions. This review summarizes contemporary insights into the mechanisms underlying nuclear force transmission in MCPs and myofibers. We discuss how the cytoskeleton and nuclear reorganizations during myogenic differentiation may affect force transmission and nuclear mechanotransduction. We also discuss how to apply these findings in the context of muscular disorders. Finally, we highlight current gaps in knowledge and opportunities for further research in the field.
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Affiliation(s)
- Saline Jabre
- Sorbonne Université, INSERM UMRS-974 and Institut de Myologie, 75013 Paris, France;
- Department of Biology, Faculty of Arts and Sciences, Holy Spirit University of Kasik (USEK), Jounieh 446, Lebanon;
| | - Walid Hleihel
- Department of Biology, Faculty of Arts and Sciences, Holy Spirit University of Kasik (USEK), Jounieh 446, Lebanon;
- Department of Basic Health Sciences, Faculty of Medicine, Holy Spirit University of Kaslik (USEK), Jounieh 446, Lebanon
| | - Catherine Coirault
- Sorbonne Université, INSERM UMRS-974 and Institut de Myologie, 75013 Paris, France;
- Correspondence:
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7
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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: 0.5] [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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Lamin A/C Assembly Defects in LMNA-Congenital Muscular Dystrophy Is Responsible for the Increased Severity of the Disease Compared with Emery-Dreifuss Muscular Dystrophy. Cells 2020; 9:cells9040844. [PMID: 32244403 PMCID: PMC7226786 DOI: 10.3390/cells9040844] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2020] [Revised: 03/24/2020] [Accepted: 03/27/2020] [Indexed: 01/13/2023] Open
Abstract
LMNA encodes for Lamin A/C, type V intermediate filaments that polymerize under the inner nuclear membrane to form the nuclear lamina. A small fraction of Lamin A/C, less polymerized, is also found in the nucleoplasm. Lamin A/C functions include roles in nuclear resistance to mechanical stress and gene regulation. LMNA mutations are responsible for a wide variety of pathologies, including Emery–Dreifuss (EDMD) and LMNA-related congenital muscular dystrophies (L-CMD) without clear genotype–phenotype correlations. Both diseases presented with striated muscle disorders although L-CMD symptoms appear much earlier and are more severe. Seeking for pathomechanical differences to explain the severity of L-CMD mutations, we performed an in silico analysis of the UMD-LMNA database and found that L-CMD mutations mainly affect residues involved in Lamin dimer and tetramer stability. In line with this, we found increased nucleoplasmic Lamin A/C in L-CMD patient fibroblasts and mouse myoblasts compared to the control and EDMD. L-CMD myoblasts show differentiation defects linked to their inability to upregulate muscle specific nuclear envelope (NE) proteins expression. NE proteins were mislocalized, leading to misshapen nuclei. We conclude that these defects are due to both the absence of Lamin A/C from the nuclear lamina and its maintenance in the nucleoplasm of myotubes.
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Nesprin-1-alpha2 associates with kinesin at myotube outer nuclear membranes, but is restricted to neuromuscular junction nuclei in adult muscle. Sci Rep 2019; 9:14202. [PMID: 31578382 PMCID: PMC6775114 DOI: 10.1038/s41598-019-50728-6] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2019] [Accepted: 09/03/2019] [Indexed: 12/16/2022] Open
Abstract
Nesprins, nuclear envelope spectrin-repeat proteins encoded by the SYNE1 and SYNE2 genes, are involved in localization of nuclei. The short isoform, nesprin-1-alpha2, is required for relocation of the microtubule organizer function from centromeres to the nuclear rim during myogenesis. Using specific antibodies, we now show that both nesprin-1-alpha2 and nesprin-1-giant co-localize with kinesin at the junctions of concatenated nuclei and at the outer poles of nuclear chains in human skeletal myotubes. In adult muscle, nesprin-1-alpha2 was found, together with kinesin, only on nuclei associated with neuromuscular junctions, whereas all adult cardiomyocyte nuclei expressed nesprin-1-alpha2. In a proteomics study, kinesin heavy and light chains were the only significant proteins in myotube extracts pulled down by nesprin-1-alpha2, but not by a mutant lacking the highly-conserved STAR domain (18 amino-acids, including the LEWD motif). The results support a function for nesprin-1-alpha2 in the specific localization of skeletal muscle nuclei mediated by kinesins and suggest that its primary role is at the outer nuclear membrane.
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10
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Abstract
Microtubule-organizing centers move from centrosomes to the nuclear envelope during muscle development. The KASH protein Nesprin-1α recruits pericentriolar material to the surface of myotube nuclei, where it nucleates microtubules to ensure even spacing of nuclei within the developing myotube.
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Affiliation(s)
- Daniel A Starr
- Department of Molecular and Cellular Biology, University of California, Davis, USA.
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11
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Kölbel H, Abicht A, Schwartz O, Katona I, Paulus W, Neuen-Jacob E, Weis J, Schara U. Characteristic clinical and ultrastructural findings in nesprinopathies. Eur J Paediatr Neurol 2019; 23:254-261. [PMID: 30626539 DOI: 10.1016/j.ejpn.2018.12.011] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/25/2018] [Revised: 12/18/2018] [Accepted: 12/22/2018] [Indexed: 01/27/2023]
Abstract
AIMS To define the neurological and neuropathological alterations caused by SYNE1 mutations. METHODS We describe 5 patients (3 males, 2 females; age 3-24 years) from 3 families. The diagnostic work-up included three muscle biopsies and two nerve biopsies in three of the cases. RESULTS Three different phenotypes were discerned. Two patients showed progressive ataxia, mental retardation, neuropathy and radially deviated thumbs (spinocerebellar ataxia, SCAR, type 8 phenotype). Two patients had mild congenital myopathy with restrictive lung disease, clubfeet and thumb anomalies (myopathic arthrogryposis). One patient had congenital myopathy with dilated cardiomyopathy and adducted thumbs (Emery-Dreifuss Muscular Dystrophy, EDMD, type 4). Light microscopy of the three muscle biopsies revealed chronic non-necrotizing myopathy without rimmed vacuoles in all cases combined with neurogenic atrophy in one case. The two nerve biopsies showed predominantly axonal neuropathy with demyelinating features. Nuclear alterations, most notably lobulation and focal widening of the space between inner and outer leaflet of the nuclear envelope, were a prominent consistent feature of myonuclei and Schwann cell nuclei in each of the three muscle specimens and one nerve specimen that could be examined by electron microscopy. CONCLUSION Thumb abnormalities and nuclear envelope alterations are characteristic for SYNE 1 mutations. Schwann cell nuclei are affected, indicating that such nuclear envelope changes in glial cells contribute to the neurodegenerative phenotype in human nesprinopathies.
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Affiliation(s)
- Heike Kölbel
- Department of Pediatric Neurology, Developmental Neurology and Social Pediatrics, University of Essen, Germany.
| | - Angela Abicht
- Medical Genetics Center, Munich and Friedrich-Baur-Institute, Ludwig-Maximilians-University Munich, Germany
| | - Oliver Schwartz
- Department of Pediatric Neurology, University of Münster, Germany
| | - Istvan Katona
- Institute of Neuropathology, RWTH Aachen University Hospital, Germany
| | - Werner Paulus
- Institute of Neuropathology, University of Münster, Germany
| | - Eva Neuen-Jacob
- Institute of Neuropathology, University of Düsseldorf, Germany
| | - Joachim Weis
- Institute of Neuropathology, RWTH Aachen University Hospital, Germany
| | - Ulrike Schara
- Department of Pediatric Neurology, Developmental Neurology and Social Pediatrics, University of Essen, Germany
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12
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Brull A, Morales Rodriguez B, Bonne G, Muchir A, Bertrand AT. The Pathogenesis and Therapies of Striated Muscle Laminopathies. Front Physiol 2018; 9:1533. [PMID: 30425656 PMCID: PMC6218675 DOI: 10.3389/fphys.2018.01533] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2018] [Accepted: 10/11/2018] [Indexed: 01/04/2023] Open
Abstract
Emery-Dreifuss muscular dystrophy (EDMD) is a genetic condition characterized by early contractures, skeletal muscle weakness, and cardiomyopathy. During the last 20 years, various genetic approaches led to the identification of causal genes of EDMD and related disorders, all encoding nuclear envelope proteins. By their respective localization either at the inner nuclear membrane or the outer nuclear membrane, these proteins interact with each other and establish a connection between the nucleus and the cytoskeleton. Beside this physical link, these proteins are also involved in mechanotransduction, responding to environmental cues, such as increased tension of the cytoskeleton, by the activation or repression of specific sets of genes. This ability of cells to adapt to environmental conditions is altered in EDMD. Increased knowledge on the pathophysiology of EDMD has led to the development of drug or gene therapies that have been tested on mouse models. This review proposed an overview of the functions played by the different proteins involved in EDMD and related disorders and the current therapeutic approaches tested so far.
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Affiliation(s)
- Astrid Brull
- Sorbonne Université, INSERM, Institut de Myologie, Center of Research in Myology, UMRS 974, Paris, France
| | - Blanca Morales Rodriguez
- Sorbonne Université, INSERM, Institut de Myologie, Center of Research in Myology, UMRS 974, Paris, France.,Sanofi R&D, Chilly Mazarin, France
| | - Gisèle Bonne
- Sorbonne Université, INSERM, Institut de Myologie, Center of Research in Myology, UMRS 974, Paris, France
| | - Antoine Muchir
- Sorbonne Université, INSERM, Institut de Myologie, Center of Research in Myology, UMRS 974, Paris, France
| | - Anne T Bertrand
- Sorbonne Université, INSERM, Institut de Myologie, Center of Research in Myology, UMRS 974, Paris, France
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13
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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: 20] [Impact Index Per Article: 3.3] [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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14
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Detection of SUN1 Splicing Variants at the mRNA and Protein Levels in Cancer. Methods Mol Biol 2018. [PMID: 30141053 DOI: 10.1007/978-1-4939-8691-0_21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
Abstract
The linker of nucleoskeleton and cytoskeleton (LINC) complex, containing the proteins SUN and nesprin, is the fundamental structural unit of the nuclear envelope. The neoplastic-based regulation of the LINC complex in cancer tissues has become increasingly recognized in recent years, including the altered expression, somatic mutation, and methylation of genes. However, precisely how mutations and deregulated expression of the LINC complex contribute to the pathogenic mechanisms of tumorigenesis remain to be elucidated, mainly because of several technical difficulties. First, both the SUN and SYNE (encoding nesprin) genes give rise to a vast number of splicing variants. Second, immunoprecipitation experiments of endogenous SUN and nesprin proteins are difficult owing to the lack of suitable reagents as well as the limited solubility of these proteins in mild extraction conditions. Here, we describe three protocols to investigate these aspects: (1) immunohistochemistry to determine the expression levels and localization of the LINC complex in cancer tissue, (2) detection of SUN1 splicing variants at the mRNA level, and (3) detection of SUN1 splicing variants and binding partners at the protein level.
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15
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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: 2.5] [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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16
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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: 6.0] [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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17
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Mouse models of nesprin-related diseases. Biochem Soc Trans 2018; 46:669-681. [PMID: 29784648 DOI: 10.1042/bst20180085] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2018] [Revised: 04/05/2018] [Accepted: 04/20/2018] [Indexed: 02/05/2023]
Abstract
Nesprins (nuclear envelope spectrin repeat proteins) are a family of multi-isomeric scaffolding proteins. Nesprins form the LInker of Nucleoskeleton-and-Cytoskeleton (LINC) complex with SUN (Sad1p/UNC84) domain-containing proteins at the nuclear envelope, in association with lamin A/C and emerin, linking the nucleoskeleton to the cytoskeleton. The LINC complex serves as both a physical linker between the nuclear lamina and the cytoskeleton and a mechanosensor. The LINC complex has a broad range of functions and is involved in maintaining nuclear architecture, nuclear positioning and migration, and also modulating gene expression. Over 80 disease-related variants have been identified in SYNE-1/2 (nesprin-1/2) genes, which result in muscular or central nervous system disorders including autosomal dominant Emery-Dreifuss muscular dystrophy, dilated cardiomyopathy and autosomal recessive cerebellar ataxia type 1. To date, 17 different nesprin mouse lines have been established to mimic these nesprin-related human diseases, which have provided valuable insights into the roles of nesprin and its scaffold LINC complex in a tissue-specific manner. In this review, we summarise the existing nesprin mouse models, compare their phenotypes and discuss the potential mechanisms underlying nesprin-associated diseases.
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18
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Nesprin-1/2: roles in nuclear envelope organisation, myogenesis and muscle disease. Biochem Soc Trans 2018; 46:311-320. [PMID: 29487227 DOI: 10.1042/bst20170149] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2017] [Revised: 01/12/2018] [Accepted: 01/17/2018] [Indexed: 02/05/2023]
Abstract
Nesprins (nuclear envelope spectrin repeat proteins) are multi-isomeric scaffolding proteins. Nesprin-1 and -2 are highly expressed in skeletal and cardiac muscles and together with SUN (Sad1p/UNC84) domain-containing proteins form the LInker of Nucleoskeleton and Cytoskeleton (LINC) complex at the nuclear envelope in association with lamin A/C and emerin. Mutations in nesprin-1/2 have been found in patients with autosomal dominant Emery-Dreifuss muscular dystrophy (EDMD) as well as dilated cardiomyopathy (DCM). Several lines of evidence indicate that compromised LINC complex function is the critical step leading to muscle disease. Here, we review recent advances in our understanding of the functions of nesprin-1/2 in the LINC complex and mechanistic insights into how mutations in nesprin-1/2 lead to nesprin-related muscle diseases, in particular DCM and EDMD.
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19
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Zhou C, Li C, Zhou B, Sun H, Koullourou V, Holt I, Puckelwartz MJ, Warren DT, Hayward R, Lin Z, Zhang L, Morris GE, McNally EM, Shackleton S, Rao L, Shanahan CM, Zhang Q. Novel nesprin-1 mutations associated with dilated cardiomyopathy cause nuclear envelope disruption and defects in myogenesis. Hum Mol Genet 2017; 26:2258-2276. [PMID: 28398466 PMCID: PMC5458344 DOI: 10.1093/hmg/ddx116] [Citation(s) in RCA: 70] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2017] [Accepted: 03/22/2017] [Indexed: 02/05/2023] Open
Abstract
Nesprins-1 and -2 are highly expressed in skeletal and cardiac muscle and together with SUN (Sad1p/UNC84)-domain containing proteins and lamin A/C form the LInker of Nucleoskeleton-and-Cytoskeleton (LINC) bridging complex at the nuclear envelope (NE). Mutations in nesprin-1/2 have previously been found in patients with autosomal dominant Emery–Dreifuss muscular dystrophy (EDMD) as well as dilated cardiomyopathy (DCM). In this study, three novel rare variants (R8272Q, S8381C and N8406K) in the C-terminus of the SYNE1 gene (nesprin-1) were identified in seven DCM patients by mutation screening. Expression of these mutants caused nuclear morphology defects and reduced lamin A/C and SUN2 staining at the NE. GST pull-down indicated that nesprin-1/lamin/SUN interactions were disrupted. Nesprin-1 mutations were also associated with augmented activation of the ERK pathway in vitro and in hearts in vivo. During C2C12 muscle cell differentiation, nesprin-1 levels are increased concomitantly with kinesin light chain (KLC-1/2) and immunoprecipitation and GST pull-down showed that these proteins interacted via a recently identified LEWD domain in the C-terminus of nesprin-1. Expression of nesprin-1 mutants in C2C12 cells caused defects in myoblast differentiation and fusion associated with dysregulation of myogenic transcription factors and disruption of the nesprin-1 and KLC-1/2 interaction at the outer nuclear membrane. Expression of nesprin-1α2 WT and mutants in zebrafish embryos caused heart developmental defects that varied in severity. These findings support a role for nesprin-1 in myogenesis and muscle disease, and uncover a novel mechanism whereby disruption of the LINC complex may contribute to the pathogenesis of DCM.
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Affiliation(s)
- Can Zhou
- King's College London British Heart Foundation Centre of Research Excellence, Cardiovascular Division, London SE5 9NU, UK.,Department of Cardiology, West China Hospital of Sichuan University, Chengdu 610041, China
| | - Chen Li
- King's College London British Heart Foundation Centre of Research Excellence, Cardiovascular Division, London SE5 9NU, UK.,Department of Cardiology, West China Hospital of Sichuan University, Chengdu 610041, China
| | - Bin Zhou
- Laboratory of Molecular Translational Medicine.,Key Laboratory of Obstetric & Gynecologic and Pediatric Diseases and Birth Defects of Ministry of Education
| | - Huaqin Sun
- Key Laboratory of Obstetric & Gynecologic and Pediatric Diseases and Birth Defects of Ministry of Education.,SCU-CUHK Joint Laboratory for Reproductive Medicine, West China Second University Hospital, Sichuan University, Chengdu, 610041, China
| | - Victoria Koullourou
- King's College London British Heart Foundation Centre of Research Excellence, Cardiovascular Division, London SE5 9NU, UK.,Department of Molecular and Cell Biology, University of Leicester, Leicester LE1 9HN, UK
| | - Ian Holt
- Wolfson Centre for Inherited Neuromuscular Disease, RJAH Orthopaedic Hospital, Oswestry SY10?7AG, UK and Institute for Science and Technology in Medicine, Keele University, ST5?5BG, UK
| | - Megan J Puckelwartz
- Center for Genetic Medicine, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA
| | - Derek T Warren
- King's College London British Heart Foundation Centre of Research Excellence, Cardiovascular Division, London SE5?9NU, UK
| | - Robert Hayward
- King's College London British Heart Foundation Centre of Research Excellence, Cardiovascular Division, London SE5?9NU, UK
| | - Ziyuan Lin
- Key Laboratory of Obstetric & Gynecologic and Pediatric Diseases and Birth Defects of Ministry of Education.,SCU-CUHK Joint Laboratory for Reproductive Medicine, West China Second University Hospital, Sichuan University, Chengdu, 610041, China
| | - Lin Zhang
- Laboratory of Molecular Translational Medicine.,Key Laboratory of Obstetric & Gynecologic and Pediatric Diseases and Birth Defects of Ministry of Education
| | - Glenn E Morris
- Wolfson Centre for Inherited Neuromuscular Disease, RJAH Orthopaedic Hospital, Oswestry SY10?7AG, UK and Institute for Science and Technology in Medicine, Keele University, ST5?5BG, UK
| | - Elizabeth M McNally
- Center for Genetic Medicine, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA
| | - Sue Shackleton
- Department of Molecular and Cell Biology, University of Leicester, Leicester LE1?9HN, UK
| | - Li Rao
- Department of Cardiology, West China Hospital of Sichuan University, Chengdu 610041, China
| | - Catherine M Shanahan
- King's College London British Heart Foundation Centre of Research Excellence, Cardiovascular Division, London SE5?9NU, UK
| | - Qiuping Zhang
- King's College London British Heart Foundation Centre of Research Excellence, Cardiovascular Division, London SE5?9NU, UK
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20
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Nesprin-1α-Dependent Microtubule Nucleation from the Nuclear Envelope via Akap450 Is Necessary for Nuclear Positioning in Muscle Cells. Curr Biol 2017; 27:2999-3009.e9. [PMID: 28966089 PMCID: PMC5640514 DOI: 10.1016/j.cub.2017.08.031] [Citation(s) in RCA: 95] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2017] [Revised: 08/08/2017] [Accepted: 08/15/2017] [Indexed: 11/20/2022]
Abstract
The nucleus is the main microtubule-organizing center (MTOC) in muscle cells due to the accumulation of centrosomal proteins and microtubule (MT) nucleation activity at the nuclear envelope (NE) [1, 2, 3, 4]. The relocalization of centrosomal proteins, including Pericentrin, Pcm1, and γ-tubulin, depends on Nesprin-1, an outer nuclear membrane (ONM) protein that connects the nucleus to the cytoskeleton via its N-terminal region [5, 6, 7]. Nesprins are also involved in the recruitment of kinesin to the NE and play a role in nuclear positioning in skeletal muscle cells [8, 9, 10, 11, 12]. However, a function for MT nucleation from the NE in nuclear positioning has not been established. Using the proximity-dependent biotin identification (BioID) method [13, 14], we found several centrosomal proteins, including Akap450, Pcm1, and Pericentrin, whose association with Nesprin-1α is increased in differentiated myotubes. We show that Nesprin-1α recruits Akap450 to the NE independently of kinesin and that Akap450, but not other centrosomal proteins, is required for MT nucleation from the NE. Furthermore, we demonstrate that this mechanism is disrupted in congenital muscular dystrophy patient myotubes carrying a nonsense mutation within the SYNE1 gene (23560 G>T) encoding Nesprin-1 [15, 16]. Finally, using computer simulation and cell culture systems, we provide evidence for a role of MT nucleation from the NE on nuclear spreading in myotubes. Our data thus reveal a novel function for Nesprin-1α/Nesprin-1 in nuclear positioning through recruitment of Akap450-mediated MT nucleation activity to the NE. BioID of Nesprin-1α identifies centrosomal proteins at myotube nuclear envelope Nesprin-1α-containing LINC complexes recruit Akap450 to myotube nuclear envelope Akap450 is required for microtubule nucleation at the nuclear envelope Microtubule nucleation at the nuclear envelope is involved in nuclear positioning
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21
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Fry AM, Sampson J, Shak C, Shackleton S. Recent advances in pericentriolar material organization: ordered layers and scaffolding gels. F1000Res 2017; 6:1622. [PMID: 29026530 PMCID: PMC5583744 DOI: 10.12688/f1000research.11652.1] [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] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 09/01/2017] [Indexed: 12/11/2022] Open
Abstract
The centrosome is an unusual organelle that lacks a surrounding membrane, raising the question of what limits its size and shape. Moreover, while electron microscopy (EM) has provided a detailed view of centriole architecture, there has been limited understanding of how the second major component of centrosomes, the pericentriolar material (PCM), is organized. Here, we summarize exciting recent findings from super-resolution fluorescence imaging, structural biology, and biochemical reconstitution that together reveal the presence of ordered layers and complex gel-like scaffolds in the PCM. Moreover, we discuss how this is leading to a better understanding of the process of microtubule nucleation, how alterations in PCM size are regulated in cycling and differentiated cells, and why mutations in PCM components lead to specific human pathologies.
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Affiliation(s)
- Andrew M Fry
- Department of Molecular and Cell Biology, University of Leicester, Leicester, UK
| | - Josephina Sampson
- Department of Molecular and Cell Biology, University of Leicester, Leicester, UK
| | - Caroline Shak
- Department of Molecular and Cell Biology, University of Leicester, Leicester, UK
| | - Sue Shackleton
- Department of Molecular and Cell Biology, University of Leicester, Leicester, UK
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22
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Potter C, Zhu W, Razafsky D, Ruzycki P, Kolesnikov AV, Doggett T, Kefalov VJ, Betleja E, Mahjoub MR, Hodzic D. Multiple Isoforms of Nesprin1 Are Integral Components of Ciliary Rootlets. Curr Biol 2017. [PMID: 28625779 DOI: 10.1016/j.cub.2017.05.066] [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] [Indexed: 12/14/2022]
Abstract
SYNE1 (synaptic nuclear envelope 1) encodes multiple isoforms of Nesprin1 (nuclear envelope spectrin 1) that associate with the nuclear envelope (NE) through a C-terminal KASH (Klarsicht/Anc1/Syne homology) domain (Figure 1A) [1-4]. This domain interacts directly with the SUN (Sad1/Unc84) domain of Sun proteins [5-7], a family of transmembrane proteins of the inner nuclear membrane (INM) [8, 9], to form the so-called LINC complexes (linkers of the nucleoskeleton and cytoskeleton) that span the entire NE and mediate nuclear positioning [10-12]. In a stark departure from this classical depiction of Nesprin1 in the context of the NE, we report here that rootletin recruits Nesprin1α at the ciliary rootlets of photoreceptors and identify asymmetric NE aggregates of Nesprin1α and Sun2 that dock filaments of rootletin at the nuclear surface. In NIH 3T3 cells, we show that recombinant rootletin filaments also dock to the NE through the specific recruitment of an ∼600-kDa endogenous isoform of Nesprin1 (Nes1600kDa) and of Sun2. In agreement with the association of Nesprin1α with photoreceptor ciliary rootlets and the functional interaction between rootletin and Nesprin1 in fibroblasts, we demonstrate that multiple isoforms of Nesprin1 are integral components of ciliary rootlets of multiciliated ependymal and tracheal cells. Together, these data provide a novel functional paradigm for Nesprin1 at ciliary rootlets and suggest that the wide spectrum of human pathologies linked to truncating mutations of SYNE1 [13-15] may originate in part from ciliary defects.
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Affiliation(s)
- Chloe Potter
- Department of Ophthalmology and Visual Sciences, Washington University School of Medicine, 660 S. Euclid Avenue, St. Louis, MO 63110, USA
| | - Wanqiu Zhu
- Department of Ophthalmology and Visual Sciences, Washington University School of Medicine, 660 S. Euclid Avenue, St. Louis, MO 63110, USA
| | - David Razafsky
- Department of Ophthalmology and Visual Sciences, Washington University School of Medicine, 660 S. Euclid Avenue, St. Louis, MO 63110, USA
| | - Philip Ruzycki
- Department of Ophthalmology and Visual Sciences, Washington University School of Medicine, 660 S. Euclid Avenue, St. Louis, MO 63110, USA
| | - Alexander V Kolesnikov
- Department of Ophthalmology and Visual Sciences, Washington University School of Medicine, 660 S. Euclid Avenue, St. Louis, MO 63110, USA
| | - Teresa Doggett
- Department of Ophthalmology and Visual Sciences, Washington University School of Medicine, 660 S. Euclid Avenue, St. Louis, MO 63110, USA
| | - Vladimir J Kefalov
- Department of Ophthalmology and Visual Sciences, Washington University School of Medicine, 660 S. Euclid Avenue, St. Louis, MO 63110, USA
| | - Ewelina Betleja
- Division of Nephrology, Department of Medicine, Washington University School of Medicine, 660 S. Euclid Avenue, St. Louis, MO 63110, USA
| | - Moe R Mahjoub
- Division of Nephrology, Department of Medicine, Washington University School of Medicine, 660 S. Euclid Avenue, St. Louis, MO 63110, USA
| | - Didier Hodzic
- Department of Ophthalmology and Visual Sciences, Washington University School of Medicine, 660 S. Euclid Avenue, St. Louis, MO 63110, USA.
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23
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Schwartz C, Fischer M, Mamchaoui K, Bigot A, Lok T, Verdier C, Duperray A, Michel R, Holt I, Voit T, Quijano-Roy S, Bonne G, Coirault C. Lamins and nesprin-1 mediate inside-out mechanical coupling in muscle cell precursors through FHOD1. Sci Rep 2017; 7:1253. [PMID: 28455503 PMCID: PMC5430732 DOI: 10.1038/s41598-017-01324-z] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2016] [Accepted: 03/27/2017] [Indexed: 02/03/2023] Open
Abstract
LINC complexes are crucial for the response of muscle cell precursors to the rigidity of their environment, but the mechanisms explaining this behaviour are not known. Here we show that pathogenic mutations in LMNA or SYNE-1 responsible for severe muscle dystrophies reduced the ability of human muscle cell precursors to adapt to substrates of different stiffness. Plated on muscle-like stiffness matrix, mutant cells exhibited contractile stress fibre accumulation, increased focal adhesions, and higher traction force than controls. Inhibition of Rho-associated kinase (ROCK) prevented cytoskeletal defects, while inhibiting myosin light chain kinase or phosphorylation of focal adhesion kinase was ineffective. Depletion or inactivation of a ROCK-dependent regulator of actin remodelling, the formin FHOD1, largely rescued morphology in mutant cells. The functional integrity of lamin and nesprin-1 is thus required to modulate the FHOD1 activity and the inside-out mechanical coupling that tunes the cell internal stiffness to match that of its soft, physiological-like environment.
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Affiliation(s)
- Christine Schwartz
- Sorbonne Universités, UPMC Univ Paris 06, INSERM UMRS974, CNRS FRE3617, Centre for Research in Myology, Paris, France
| | - Martina Fischer
- Sorbonne Universités, UPMC Univ Paris 06, INSERM UMRS974, CNRS FRE3617, Centre for Research in Myology, Paris, France
| | - Kamel Mamchaoui
- Sorbonne Universités, UPMC Univ Paris 06, INSERM UMRS974, CNRS FRE3617, Centre for Research in Myology, Paris, France
| | - Anne Bigot
- Sorbonne Universités, UPMC Univ Paris 06, INSERM UMRS974, CNRS FRE3617, Centre for Research in Myology, Paris, France
| | - Thevy Lok
- Univ. Grenoble Alpes, LIPHY, F-38000, Grenoble, France
- CNRS, LIPHY, F-38000, Grenoble, France
| | - Claude Verdier
- Univ. Grenoble Alpes, LIPHY, F-38000, Grenoble, France
- CNRS, LIPHY, F-38000, Grenoble, France
| | - Alain Duperray
- INSERM, Institut Albert Bonniot, U1209, F-38000, Grenoble, France
- Université Grenoble Alpes, IAB, F-38000, Grenoble, France
| | - Richard Michel
- Univ. Grenoble Alpes, LIPHY, F-38000, Grenoble, France
- CNRS, LIPHY, F-38000, Grenoble, France
| | - Ian Holt
- Wolfson Centre for Inherited Neuromuscular Disease, RJAH Orthopaedic Hospital, Oswestry, SY10 7AG, UK
| | - Thomas Voit
- Sorbonne Universités, UPMC Univ Paris 06, INSERM UMRS974, CNRS FRE3617, Centre for Research in Myology, Paris, France
- NIHR Great Ormond Street Biomedical Research Centre, Institute of Child Health, University College London, 30 Guilford Street, London, WC1N 1EH, UK
| | | | - Gisèle Bonne
- Sorbonne Universités, UPMC Univ Paris 06, INSERM UMRS974, CNRS FRE3617, Centre for Research in Myology, Paris, France
| | - Catherine Coirault
- Sorbonne Universités, UPMC Univ Paris 06, INSERM UMRS974, CNRS FRE3617, Centre for Research in Myology, Paris, France.
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24
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Rajgor D, Hanley JG, Shanahan CM. Identification of novel nesprin-1 binding partners and cytoplasmic matrin-3 in processing bodies. Mol Biol Cell 2016; 27:3894-3902. [PMID: 27733621 PMCID: PMC5170611 DOI: 10.1091/mbc.e16-06-0346] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2016] [Revised: 09/20/2016] [Accepted: 10/05/2016] [Indexed: 11/25/2022] Open
Abstract
Several new nesprin-1 binding partners were identified, of which many are well-characterized RNA-binding proteins involved in various forms of nuclear RNA-processing events. Matrin-3 was one such protein identified, and a new cytoplasmic localization for matrin-3 is shown. Nesprins are highly conserved spectrin repeat–containing scaffold proteins predominantly known to function at the nuclear envelope (NE). However, nesprin isoforms are emerging with localizations and scaffolding functions at sites away from the NE, suggesting their functions are more diverse than originally thought. In this study, we combined nesprin-1 coimmunoprecipitations with mass spectrometry to identify novel nesprin-1 binding partners for isoforms that localize to subcellular compartments beyond the NE. We show that one of these interactors, matrin-3 (matr3), localizes to mRNA processing bodies (PBs), where we have previously shown a nesprin-1 isoform to localize. Furthermore, we show that Matr3 is part of PB mRNP complexes, is a regulator of miRNA-mediated gene silencing, and possibly shuttles to stress granules in stressed cells. More importantly, we identify a new C-terminally truncated Matr3 isoform that is likely to be involved in these functions and PB localization. This study highlights several novel nesprin-1 binding partners and a new function and localization for Matr3 in cytoplasmic RNA granules.
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Affiliation(s)
- Dipen Rajgor
- Cardiovascular Division, King's College London, London SE5 9NU, United Kingdom .,Department of Biochemistry, University of Bristol, Bristol BS8 1TD, United Kingdom
| | - Jonathan G Hanley
- Department of Biochemistry, University of Bristol, Bristol BS8 1TD, United Kingdom
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