1
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Genomic instability caused by Arp2/3 complex inactivation results in micronucleus biogenesis and cellular senescence. PLoS Genet 2023; 19:e1010045. [PMID: 36706133 PMCID: PMC9907832 DOI: 10.1371/journal.pgen.1010045] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2022] [Revised: 02/08/2023] [Accepted: 01/10/2023] [Indexed: 01/28/2023] Open
Abstract
The Arp2/3 complex is an actin nucleator with well-characterized activities in cell morphogenesis and movement, but its roles in nuclear processes are relatively understudied. We investigated how the Arp2/3 complex affects genomic integrity and cell cycle progression using mouse fibroblasts containing an inducible knockout (iKO) of the ArpC2 subunit. We show that permanent Arp2/3 complex ablation results in DNA damage, the formation of cytosolic micronuclei, and cellular senescence. Micronuclei arise in ArpC2 iKO cells due to chromatin segregation defects during mitosis and premature mitotic exits. Such phenotypes are explained by the presence of damaged DNA fragments that fail to attach to the mitotic spindle, abnormalities in actin assembly during metaphase, and asymmetric microtubule architecture during anaphase. In the nuclei of Arp2/3-depleted cells, the tumor suppressor p53 is activated and the cell cycle inhibitor Cdkn1a/p21 mediates a G1 arrest. In the cytosol, micronuclei are recognized by the DNA sensor cGAS, which is important for stimulating a STING- and IRF3-associated interferon response. These studies establish functional requirements for the mammalian Arp2/3 complex in mitotic spindle organization and genome stability. They also expand our understanding of the mechanisms leading to senescence and suggest that cytoskeletal dysfunction is an underlying factor in biological aging.
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2
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Bellinvia E, García-González J, Cifrová P, Martinek J, Sikorová L, Havelková L, Schwarzerová K. CRISPR-Cas9 Arabidopsis mutants of genes for ARPC1 and ARPC3 subunits of ARP2/3 complex reveal differential roles of complex subunits. Sci Rep 2022; 12:18205. [PMID: 36307477 PMCID: PMC9616901 DOI: 10.1038/s41598-022-22982-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2022] [Accepted: 10/21/2022] [Indexed: 12/31/2022] Open
Abstract
Protein complex Arp2/3 has a conserved role in the nucleation of branched actin filaments. It is constituted of seven subunits, including actin-like subunits ARP2 and ARP3 plus five other subunits called Arp2/3 Complex Component 1 to 5, which are not related to actin. Knock-out plant mutants lacking individual plant ARP2/3 subunits have a typical phenotype of distorted trichomes, altered pavement cells shape and defects in cell adhesion. While knock-out mutant Arabidopsis plants for most ARP2/3 subunits have been characterized before, Arabidopsis plant mutants missing ARPC1 and ARPC3 subunits have not yet been described. Using CRISPR/Cas9, we generated knock-out mutants lacking ARPC1 and ARPC3 subunits. We confirmed that the loss of ARPC1 subunits results in the typical ARP2/3 mutant phenotype. However, the mutants lacking ARPC3 subunits resulted in plants with surprisingly different phenotypes. Our results suggest that plant ARP2/3 complex function in trichome shaping does not require ARPC3 subunit, while the fully assembled complex is necessary for the establishment of correct cell adhesion in the epidermis.
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Affiliation(s)
- Erica Bellinvia
- grid.4491.80000 0004 1937 116XDepartment of Experimental Plant Biology, Faculty of Science, Charles University, Prague, Czech Republic
| | - Judith García-González
- grid.4491.80000 0004 1937 116XDepartment of Experimental Plant Biology, Faculty of Science, Charles University, Prague, Czech Republic
| | - Petra Cifrová
- grid.4491.80000 0004 1937 116XDepartment of Experimental Plant Biology, Faculty of Science, Charles University, Prague, Czech Republic
| | - Jan Martinek
- grid.4491.80000 0004 1937 116XDepartment of Experimental Plant Biology, Faculty of Science, Charles University, Prague, Czech Republic
| | - Lenka Sikorová
- grid.4491.80000 0004 1937 116XDepartment of Experimental Plant Biology, Faculty of Science, Charles University, Prague, Czech Republic
| | - Lenka Havelková
- grid.4491.80000 0004 1937 116XDepartment of Experimental Plant Biology, Faculty of Science, Charles University, Prague, Czech Republic
| | - Kateřina Schwarzerová
- grid.4491.80000 0004 1937 116XDepartment of Experimental Plant Biology, Faculty of Science, Charles University, Prague, Czech Republic
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3
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Omelchenko T. Cellular protrusions in 3D: Orchestrating early mouse embryogenesis. Semin Cell Dev Biol 2022; 129:63-74. [PMID: 35577698 DOI: 10.1016/j.semcdb.2022.05.005] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2022] [Revised: 05/04/2022] [Accepted: 05/04/2022] [Indexed: 12/26/2022]
Abstract
Cellular protrusions generated by the actin cytoskeleton are central to the process of building the body of the embryo. Problems with cellular protrusions underlie human diseases and syndromes, including implantation defects and pregnancy loss, congenital birth defects, and cancer. Cells use protrusive activity together with actin-myosin contractility to create an ordered body shape of the embryo. Here, I review how actin-rich protrusions are used by two major morphological cell types, epithelial and mesenchymal cells, during collective cell migration to sculpt the mouse embryo body. Pre-gastrulation epithelial collective migration of the anterior visceral endoderm is essential for establishing the anterior-posterior body axis. Gastrulation mesenchymal collective migration of the mesoderm wings is crucial for body elongation, and somite and heart formation. Analysis of mouse mutants with disrupted cellular protrusions revealed the key role of protrusions in embryonic morphogenesis and embryo survival. Recent technical approaches have allowed examination of the mechanisms that control cell and tissue movements in vivo in the complex 3D microenvironment of living mouse embryos. Advancing our understanding of protrusion-driven morphogenesis should provide novel insights into human developmental disorders and cancer metastasis.
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Affiliation(s)
- Tatiana Omelchenko
- Laboratory of Mammalian Cell Biology and Development, The Rockefeller University, 1230 York Avenue, New York 10065, USA.
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4
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Sun J, Zhong X, Fu X, Miller H, Lee P, Yu B, Liu C. The Actin Regulators Involved in the Function and Related Diseases of Lymphocytes. Front Immunol 2022; 13:799309. [PMID: 35371070 PMCID: PMC8965893 DOI: 10.3389/fimmu.2022.799309] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2021] [Accepted: 02/01/2022] [Indexed: 11/21/2022] Open
Abstract
Actin is an important cytoskeletal protein involved in signal transduction, cell structure and motility. Actin regulators include actin-monomer-binding proteins, Wiskott-Aldrich syndrome (WAS) family of proteins, nucleation proteins, actin filament polymerases and severing proteins. This group of proteins regulate the dynamic changes in actin assembly/disassembly, thus playing an important role in cell motility, intracellular transport, cell division and other basic cellular activities. Lymphocytes are important components of the human immune system, consisting of T-lymphocytes (T cells), B-lymphocytes (B cells) and natural killer cells (NK cells). Lymphocytes are indispensable for both innate and adaptive immunity and cannot function normally without various actin regulators. In this review, we first briefly introduce the structure and fundamental functions of a variety of well-known and newly discovered actin regulators, then we highlight the role of actin regulators in T cell, B cell and NK cell, and finally provide a landscape of various diseases associated with them. This review provides new directions in exploring actin regulators and promotes more precise and effective treatments for related diseases.
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Affiliation(s)
- Jianxuan Sun
- Department of Pathogen Biology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.,Department and Institute of Urology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Xingyu Zhong
- Department of Pathogen Biology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Xiaoyu Fu
- Department of Pathogen Biology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Heather Miller
- Cytek Biosciences, R&D Clinical Reagents, Fremont, CA, United States
| | - Pamela Lee
- Department of Paediatrics and Adolescent Medicine, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, Hong Kong SAR, China
| | - Bing Yu
- Department of Pathogen Biology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Chaohong Liu
- Department of Pathogen Biology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
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5
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Tur-Gracia S, Martinez-Quiles N. Emerging functions of cytoskeletal proteins in immune diseases. J Cell Sci 2021; 134:134/3/jcs253534. [PMID: 33558442 DOI: 10.1242/jcs.253534] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Immune cells are especially dependent on the proper functioning of the actin cytoskeleton, and both innate and adaptive responses rely on it. Leukocytes need to adhere not only to substrates but also to cells in order to form synapses that pass on instructions or kill infected cells. Neutrophils literally squeeze their cell body during blood extravasation and efficiently migrate to the inflammatory focus. Moreover, the development of immune cells requires the remodeling of their cytoskeleton as it depends on, among other processes, adhesive contacts and migration. In recent years, the number of reports describing cytoskeletal defects that compromise the immune system has increased immensely. Furthermore, a new emerging paradigm points toward a role for the cellular actin content as an essential component of the so-called homeostasis-altering molecular processes that induce the activation of innate immune signaling pathways. Here, we review the role of critical actin-cytoskeleton-remodeling proteins, including the Arp2/3 complex, cofilin, coronin and WD40-repeat containing protein 1 (WDR1), in immune pathophysiology, with a special focus on autoimmune and autoinflammatory traits.
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Affiliation(s)
- Sara Tur-Gracia
- Department of Immunology, Ophthalmology and ENT, Complutense University School of Medicine, 28040 Madrid, Spain
| | - Narcisa Martinez-Quiles
- Department of Immunology, Ophthalmology and ENT, Complutense University School of Medicine, 28040 Madrid, Spain .,Gregorio Marañón Health Research Institute, 28007 Madrid, Spain
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6
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Fäßler F, Dimchev G, Hodirnau VV, Wan W, Schur FKM. Cryo-electron tomography structure of Arp2/3 complex in cells reveals new insights into the branch junction. Nat Commun 2020; 11:6437. [PMID: 33353942 PMCID: PMC7755917 DOI: 10.1038/s41467-020-20286-x] [Citation(s) in RCA: 45] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2020] [Accepted: 11/24/2020] [Indexed: 12/21/2022] Open
Abstract
The actin-related protein (Arp)2/3 complex nucleates branched actin filament networks pivotal for cell migration, endocytosis and pathogen infection. Its activation is tightly regulated and involves complex structural rearrangements and actin filament binding, which are yet to be understood. Here, we report a 9.0 Å resolution structure of the actin filament Arp2/3 complex branch junction in cells using cryo-electron tomography and subtomogram averaging. This allows us to generate an accurate model of the active Arp2/3 complex in the branch junction and its interaction with actin filaments. Notably, our model reveals a previously undescribed set of interactions of the Arp2/3 complex with the mother filament, significantly different to the previous branch junction model. Our structure also indicates a central role for the ArpC3 subunit in stabilizing the active conformation.
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Affiliation(s)
- Florian Fäßler
- Institute of Science and Technology (IST) Austria, Klosterneuburg, Austria
| | - Georgi Dimchev
- Institute of Science and Technology (IST) Austria, Klosterneuburg, Austria
| | | | - William Wan
- Department of Biochemistry and Center for Structural Biology, Vanderbilt University, Nashville, United States of America
| | - Florian K M Schur
- Institute of Science and Technology (IST) Austria, Klosterneuburg, Austria.
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7
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Papalazarou V, Swaminathan K, Jaber-Hijazi F, Spence H, Lahmann I, Nixon C, Salmeron-Sanchez M, Arnold HH, Rottner K, Machesky LM. The Arp2/3 complex is crucial for colonisation of the mouse skin by melanoblasts. Development 2020; 147:dev194555. [PMID: 33028610 PMCID: PMC7687863 DOI: 10.1242/dev.194555] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Accepted: 09/22/2020] [Indexed: 01/10/2023]
Abstract
The Arp2/3 complex is essential for the assembly of branched filamentous actin, but its role in physiology and development is surprisingly little understood. Melanoblasts deriving from the neural crest migrate along the developing embryo and traverse the dermis to reach the epidermis, colonising the skin and eventually homing within the hair follicles. We have previously established that Rac1 and Cdc42 direct melanoblast migration in vivo We hypothesised that the Arp2/3 complex might be the main downstream effector of these small GTPases. Arp3 depletion in the melanocyte lineage results in severe pigmentation defects in dorsal and ventral regions of the mouse skin. Arp3 null melanoblasts demonstrate proliferation and migration defects and fail to elongate as their wild-type counterparts. Conditional deletion of Arp3 in primary melanocytes causes improper proliferation, spreading, migration and adhesion to extracellular matrix. Collectively, our results suggest that the Arp2/3 complex is absolutely indispensable in the melanocyte lineage in mouse development, and indicate a significant role in developmental processes that require tight regulation of actin-mediated motility.
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Affiliation(s)
- Vassilis Papalazarou
- CRUK Beatson Institute, Garscube Estate, Switchback Road, Bearsden, Glasgow G61 1BD, UK
- Institute of Cancer Sciences, University of Glasgow, Garscube Campus, Switchback Road, Bearsden, Glasgow G61 1QH, UK
- Centre for the Cellular Microenvironment, University of Glasgow, Glasgow G12 8LT, UK
| | - Karthic Swaminathan
- CRUK Beatson Institute, Garscube Estate, Switchback Road, Bearsden, Glasgow G61 1BD, UK
| | - Farah Jaber-Hijazi
- CRUK Beatson Institute, Garscube Estate, Switchback Road, Bearsden, Glasgow G61 1BD, UK
| | - Heather Spence
- CRUK Beatson Institute, Garscube Estate, Switchback Road, Bearsden, Glasgow G61 1BD, UK
| | - Ines Lahmann
- Cell and Molecular Biology, Institute of Biochemistry and Biotechnology, Technische Universität Braunschweig, Spielmannstrasse 7, 38106 Braunschweig, Germany
| | - Colin Nixon
- CRUK Beatson Institute, Garscube Estate, Switchback Road, Bearsden, Glasgow G61 1BD, UK
| | | | - Hans-Henning Arnold
- Cell and Molecular Biology, Institute of Biochemistry and Biotechnology, Technische Universität Braunschweig, Spielmannstrasse 7, 38106 Braunschweig, Germany
| | - Klemens Rottner
- Division of Molecular Cell Biology, Zoological Institute, Technische Universität Braunschweig, Spielmannstrasse 7, 38106 Braunschweig, Germany
- Department of Cell Biology, Helmholtz Centre for Infection Research, Inhoffenstrasse 7, 38124 Braunschweig, Germany
| | - Laura M Machesky
- CRUK Beatson Institute, Garscube Estate, Switchback Road, Bearsden, Glasgow G61 1BD, UK
- Institute of Cancer Sciences, University of Glasgow, Garscube Campus, Switchback Road, Bearsden, Glasgow G61 1QH, UK
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8
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Mechanistic Target of Rapamycin Regulates the Oligodendrocyte Cytoskeleton during Myelination. J Neurosci 2020; 40:2993-3007. [PMID: 32139584 DOI: 10.1523/jneurosci.1434-18.2020] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2018] [Revised: 02/23/2020] [Accepted: 02/26/2020] [Indexed: 12/22/2022] Open
Abstract
During differentiation, oligodendrocyte precursor cells (OPCs) extend a network of processes that make contact with axons and initiate myelination. Recent studies revealed that actin polymerization is required for initiation of myelination whereas actin depolymerization promotes myelin wrapping. Here, we used primary OPCs in culture isolated from neonatal rat cortices of both sexes and young male and female mice with oligodendrocyte-specific deletion of mechanistic target of rapamycin (mTOR) to demonstrate that mTOR regulates expression of specific cytoskeletal targets and actin reorganization in oligodendrocytes during developmental myelination. Loss or inhibition of mTOR reduced expression of profilin2 and ARPC3, actin polymerizing factors, and elevated levels of active cofilin, which mediates actin depolymerization. The deficits in actin polymerization were revealed in reduced phalloidin and deficits in oligodendrocyte cellular branching complexity at the peak of morphologic differentiation and a delay in initiation of myelination. We further show a critical role for mTOR in expression and localization of myelin basic protein (Mbp) mRNA and MBP protein to the cellular processes where it is necessary at the myelin membrane for axon wrapping. Mbp mRNA transport deficits were confirmed by single molecule RNA FISH. Moreover, expression of the kinesin family member 1B, an Mbp mRNA transport protein, was reduced in CC1+ cells in the mTOR cKO and in mTOR inhibited oligodendrocytes undergoing differentiation in vitro These data support the conclusion that mTOR regulates both initiation of myelination and axon wrapping by targeting cytoskeletal reorganization and MBP localization to oligodendrocyte processes.SIGNIFICANCE STATEMENT Myelination is essential for normal CNS development and adult axon preservation and function. The mechanistic target of rapamycin (mTOR) signaling pathway has been implicated in promoting CNS myelination; however, there is a gap in our understanding of the mechanisms by which mTOR promotes developmental myelination through regulating specific downstream targets. Here, we present evidence that mTOR promotes the initiation of myelination through regulating specific cytoskeletal targets and cellular process expansion by oligodendrocyte precursor cells as well as expression and cellular localization of myelin basic protein.
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9
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Obeidy P, Ju LA, Oehlers SH, Zulkhernain NS, Lee Q, Galeano Niño JL, Kwan RY, Tikoo S, Cavanagh LL, Mrass P, Cook AJ, Jackson SP, Biro M, Roediger B, Sixt M, Weninger W. Partial loss of actin nucleator actin-related protein 2/3 activity triggers blebbing in primary T lymphocytes. Immunol Cell Biol 2019; 98:93-113. [PMID: 31698518 PMCID: PMC7028084 DOI: 10.1111/imcb.12304] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2019] [Revised: 11/03/2019] [Accepted: 11/04/2019] [Indexed: 12/11/2022]
Abstract
T lymphocytes utilize amoeboid migration to navigate effectively within complex microenvironments. The precise rearrangement of the actin cytoskeleton required for cellular forward propulsion is mediated by actin regulators, including the actin‐related protein 2/3 (Arp2/3) complex, a macromolecular machine that nucleates branched actin filaments at the leading edge. The consequences of modulating Arp2/3 activity on the biophysical properties of the actomyosin cortex and downstream T cell function are incompletely understood. We report that even a moderate decrease of Arp3 levels in T cells profoundly affects actin cortex integrity. Reduction in total F‐actin content leads to reduced cortical tension and disrupted lamellipodia formation. Instead, in Arp3‐knockdown cells, the motility mode is dominated by blebbing migration characterized by transient, balloon‐like protrusions at the leading edge. Although this migration mode seems to be compatible with interstitial migration in three‐dimensional environments, diminished locomotion kinetics and impaired cytotoxicity interfere with optimal T cell function. These findings define the importance of finely tuned, Arp2/3‐dependent mechanophysical membrane integrity in cytotoxic effector T lymphocyte activities.
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Affiliation(s)
- Peyman Obeidy
- Immune Imaging Program, The Centenary Institute, Faculty of Medicine and Health, The University of Sydney, Camperdown, NSW, 2050, Australia
| | - Lining A Ju
- School of Biomedical Engineering, The University of Sydney, Sydney, NSW, 2006, Australia.,Heart Research Institute and Charles Perkins Centre, The University of Sydney, Sydney, NSW, 2006, Australia
| | - Stefan H Oehlers
- Tuberculosis Research Program, The Centenary Institute, The University of Sydney, Camperdown, NSW, 2050, Australia.,Discipline of Infectious Diseases & Immunology, Marie Bashir Institute, The University of Sydney, Sydney, NSW, 2006, Australia.,Sydney Medical School, The University of Sydney, Sydney, NSW, 2006, Australia
| | - Nursafwana S Zulkhernain
- Immune Imaging Program, The Centenary Institute, Faculty of Medicine and Health, The University of Sydney, Camperdown, NSW, 2050, Australia.,Sydney Medical School, The University of Sydney, Sydney, NSW, 2006, Australia
| | - Quintin Lee
- Immune Imaging Program, The Centenary Institute, Faculty of Medicine and Health, The University of Sydney, Camperdown, NSW, 2050, Australia
| | - Jorge L Galeano Niño
- EMBL Australia Node in Single Molecule Science, School of Medical Sciences, the ARC Centre of Excellence in Advanced Molecular Imaging, University of New South Wales, Kensington, NSW, 2033, Australia
| | - Rain Yq Kwan
- Immune Imaging Program, The Centenary Institute, Faculty of Medicine and Health, The University of Sydney, Camperdown, NSW, 2050, Australia
| | - Shweta Tikoo
- Immune Imaging Program, The Centenary Institute, Faculty of Medicine and Health, The University of Sydney, Camperdown, NSW, 2050, Australia.,Sydney Medical School, The University of Sydney, Sydney, NSW, 2006, Australia
| | - Lois L Cavanagh
- Immune Imaging Program, The Centenary Institute, Faculty of Medicine and Health, The University of Sydney, Camperdown, NSW, 2050, Australia
| | - Paulus Mrass
- Department of Molecular Genetics and Microbiology, University of New Mexico School of Medicine, Albuquerque, NM, 87131, USA
| | - Adam Jl Cook
- Immune Imaging Program, The Centenary Institute, Faculty of Medicine and Health, The University of Sydney, Camperdown, NSW, 2050, Australia.,Sydney Medical School, The University of Sydney, Sydney, NSW, 2006, Australia
| | - Shaun P Jackson
- Heart Research Institute and Charles Perkins Centre, The University of Sydney, Sydney, NSW, 2006, Australia.,Central Clinical School, Sydney Medical School, The University of Sydney, Sydney, NSW, 2006, Australia
| | - Maté Biro
- EMBL Australia Node in Single Molecule Science, School of Medical Sciences, the ARC Centre of Excellence in Advanced Molecular Imaging, University of New South Wales, Kensington, NSW, 2033, Australia
| | - Ben Roediger
- Immune Imaging Program, The Centenary Institute, Faculty of Medicine and Health, The University of Sydney, Camperdown, NSW, 2050, Australia
| | - Michael Sixt
- Institute of Science and Technology, Klosterneuburg, 3400, Austria
| | - Wolfgang Weninger
- Immune Imaging Program, The Centenary Institute, Faculty of Medicine and Health, The University of Sydney, Camperdown, NSW, 2050, Australia.,Department of Dermatology, Royal Prince Alfred Hospital, Camperdown, NSW, 2050, Australia.,Discipline of Dermatology, Sydney Medical School, The University of Sydney, Sydney, NSW, 2006, Australia.,Department of Dermatology, Medical University of Vienna, Vienna, 1090, Austria
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10
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Janssen E, Geha RS. Primary immunodeficiencies caused by mutations in actin regulatory proteins. Immunol Rev 2019; 287:121-134. [PMID: 30565251 DOI: 10.1111/imr.12716] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2018] [Accepted: 08/31/2018] [Indexed: 12/31/2022]
Abstract
The identification of patients with monogenic gene defects have illuminated the function of different proteins in the immune system, including proteins that regulate the actin cytoskeleton. Many of these actin regulatory proteins are exclusively expressed in leukocytes and regulate the formation and branching of actin filaments. Their absence or abnormal function leads to defects in immune cell shape, cellular projections, migration, and signaling. Through the study of patients' mutations and generation of mouse models that recapitulate the patients' phenotypes, our laboratory and others have gained a better understanding of the role these proteins play in cell biology and the underlying pathogenesis of immunodeficiencies and immune dysregulatory syndromes.
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Affiliation(s)
- Erin Janssen
- Division of Immunology, Department of Pediatrics, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts
| | - Raif S Geha
- Division of Immunology, Department of Pediatrics, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts
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11
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Randzavola LO, Strege K, Juzans M, Asano Y, Stinchcombe JC, Gawden-Bone CM, Seaman MN, Kuijpers TW, Griffiths GM. Loss of ARPC1B impairs cytotoxic T lymphocyte maintenance and cytolytic activity. J Clin Invest 2019. [PMID: 31710310 DOI: 10.1172/jci129388)] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/04/2022] Open
Abstract
CD8 cytotoxic T lymphocytes (CTLs) rely on rapid reorganization of the branched F-actin network to drive the polarized secretion of lytic granules, initiating target cell death during the adaptive immune response. Branched F-actin is generated by the nucleation factor actin-related protein 2/3 (Arp2/3) complex. Patients with mutations in the actin-related protein complex 1B (ARPC1B) subunit of Arp2/3 show combined immunodeficiency, with symptoms of immune dysregulation, including recurrent viral infections and reduced CD8+ T cell count. Here, we show that loss of ARPC1B led to loss of CTL cytotoxicity, with the defect arising at 2 different levels. First, ARPC1B is required for lamellipodia formation, cell migration, and actin reorganization across the immune synapse. Second, we found that ARPC1B is indispensable for the maintenance of TCR, CD8, and GLUT1 membrane proteins at the plasma membrane of CTLs, as recycling via the retromer and WASH complexes was impaired in the absence of ARPC1B. Loss of TCR, CD8, and GLUT1 gave rise to defects in T cell signaling and proliferation upon antigen stimulation of ARPC1B-deficient CTLs, leading to a progressive loss of CD8+ T cells. This triggered an activation-induced immunodeficiency of CTL activity in ARPC1B-deficient patients, which could explain the susceptibility to severe and prolonged viral infections.
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Affiliation(s)
- Lyra O Randzavola
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge, United Kingdom
| | - Katharina Strege
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge, United Kingdom
| | - Marie Juzans
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge, United Kingdom
| | - Yukako Asano
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge, United Kingdom
| | - Jane C Stinchcombe
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge, United Kingdom
| | - Christian M Gawden-Bone
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge, United Kingdom
| | - Matthew Nj Seaman
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge, United Kingdom
| | - Taco W Kuijpers
- Department of Blood Cell Research, Sanquin Research and Landsteiner Laboratory, Academic Medical Center, University of Amsterdam, Amsterdam, Netherlands.,Department of Pediatric Immunology, Rheumatology and Infectious Disease, Emma Children's Hospital, Medical Center Amsterdam University, Amsterdam, Netherlands
| | - Gillian M Griffiths
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge, United Kingdom
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12
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Randzavola LO, Strege K, Juzans M, Asano Y, Stinchcombe JC, Gawden-Bone CM, Seaman MN, Kuijpers TW, Griffiths GM. Loss of ARPC1B impairs cytotoxic T lymphocyte maintenance and cytolytic activity. J Clin Invest 2019; 129:5600-5614. [PMID: 31710310 PMCID: PMC6877333 DOI: 10.1172/jci129388] [Citation(s) in RCA: 55] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2019] [Accepted: 09/10/2019] [Indexed: 12/30/2022] Open
Abstract
CD8 cytotoxic T lymphocytes (CTLs) rely on rapid reorganization of the branched F-actin network to drive the polarized secretion of lytic granules, initiating target cell death during the adaptive immune response. Branched F-actin is generated by the nucleation factor actin-related protein 2/3 (Arp2/3) complex. Patients with mutations in the actin-related protein complex 1B (ARPC1B) subunit of Arp2/3 show combined immunodeficiency, with symptoms of immune dysregulation, including recurrent viral infections and reduced CD8+ T cell count. Here, we show that loss of ARPC1B led to loss of CTL cytotoxicity, with the defect arising at 2 different levels. First, ARPC1B is required for lamellipodia formation, cell migration, and actin reorganization across the immune synapse. Second, we found that ARPC1B is indispensable for the maintenance of TCR, CD8, and GLUT1 membrane proteins at the plasma membrane of CTLs, as recycling via the retromer and WASH complexes was impaired in the absence of ARPC1B. Loss of TCR, CD8, and GLUT1 gave rise to defects in T cell signaling and proliferation upon antigen stimulation of ARPC1B-deficient CTLs, leading to a progressive loss of CD8+ T cells. This triggered an activation-induced immunodeficiency of CTL activity in ARPC1B-deficient patients, which could explain the susceptibility to severe and prolonged viral infections.
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Affiliation(s)
- Lyra O. Randzavola
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge, United Kingdom
| | - Katharina Strege
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge, United Kingdom
| | - Marie Juzans
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge, United Kingdom
| | - Yukako Asano
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge, United Kingdom
| | - Jane C. Stinchcombe
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge, United Kingdom
| | | | - Matthew N.J. Seaman
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge, United Kingdom
| | - Taco W. Kuijpers
- Department of Blood Cell Research, Sanquin Research and Landsteiner Laboratory, Academic Medical Center, University of Amsterdam, Amsterdam, Netherlands
- Department of Pediatric Immunology, Rheumatology and Infectious Disease, Emma Children’s Hospital, Medical Center Amsterdam University, Amsterdam, Netherlands
| | - Gillian M. Griffiths
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge, United Kingdom
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13
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Chánez-Paredes S, Montoya-García A, Schnoor M. Cellular and pathophysiological consequences of Arp2/3 complex inhibition: role of inhibitory proteins and pharmacological compounds. Cell Mol Life Sci 2019; 76:3349-3361. [PMID: 31073744 PMCID: PMC11105272 DOI: 10.1007/s00018-019-03128-y] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2019] [Revised: 04/30/2019] [Accepted: 05/02/2019] [Indexed: 02/06/2023]
Abstract
The actin-related protein complex 2/3 (Arp2/3) generates branched actin networks important for many cellular processes such as motility, vesicular trafficking, cytokinesis, and intercellular junction formation and stabilization. Activation of Arp2/3 requires interaction with actin nucleation-promoting factors (NPFs). Regulation of Arp2/3 activity is achieved by endogenous inhibitory proteins through direct binding to Arp2/3 and competition with NPFs or by binding to Arp2/3-induced actin filaments and disassembly of branched actin networks. Arp2/3 inhibition has recently garnered more attention as it has been associated with attenuation of cancer progression, neurotoxic effects during drug abuse, and pathogen invasion of host cells. In this review, we summarize current knowledge on expression, inhibitory mechanisms and function of endogenous proteins able to inhibit Arp2/3 such as coronins, GMFs, PICK1, gadkin, and arpin. Moreover, we discuss cellular consequences of pharmacological Arp2/3 inhibition.
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Affiliation(s)
- Sandra Chánez-Paredes
- Department for Molecular Biomedicine, CINVESTAV-IPN, Av. IPN 2508, San Pedro Zacatenco, GAM, 07360, Mexico City, Mexico
| | - Armando Montoya-García
- Department for Molecular Biomedicine, CINVESTAV-IPN, Av. IPN 2508, San Pedro Zacatenco, GAM, 07360, Mexico City, Mexico
| | - Michael Schnoor
- Department for Molecular Biomedicine, CINVESTAV-IPN, Av. IPN 2508, San Pedro Zacatenco, GAM, 07360, Mexico City, Mexico.
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14
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Somech R, Lev A, Lee YN, Simon AJ, Barel O, Schiby G, Avivi C, Barshack I, Rhodes M, Yin J, Wang M, Yang Y, Rhodes J, Marcus N, Garty BZ, Stein J, Amariglio N, Rechavi G, Wiest DL, Zhang Y. Disruption of Thrombocyte and T Lymphocyte Development by a Mutation in ARPC1B. THE JOURNAL OF IMMUNOLOGY 2017; 199:4036-4045. [PMID: 29127144 DOI: 10.4049/jimmunol.1700460] [Citation(s) in RCA: 59] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/30/2017] [Accepted: 10/06/2017] [Indexed: 01/21/2023]
Abstract
Regulation of the actin cytoskeleton is crucial for normal development and function of the immune system, as evidenced by the severe immune abnormalities exhibited by patients bearing inactivating mutations in the Wiskott-Aldrich syndrome protein (WASP), a key regulator of actin dynamics. WASP exerts its effects on actin dynamics through a multisubunit complex termed Arp2/3. Despite the critical role played by Arp2/3 as an effector of WASP-mediated control over actin polymerization, mutations in protein components of the Arp2/3 complex had not previously been identified as a cause of immunodeficiency. Here, we describe two brothers with hematopoietic and immunologic symptoms reminiscent of Wiskott-Aldrich syndrome (WAS). However, these patients lacked mutations in any of the genes previously associated with WAS. Whole-exome sequencing revealed a homozygous 2 bp deletion, n.c.G623DEL-TC (p.V208VfsX20), in Arp2/3 complex component ARPC1B that causes a frame shift resulting in premature termination. Modeling of the disease in zebrafish revealed that ARPC1B plays a critical role in supporting T cell and thrombocyte development. Moreover, the defects in development caused by ARPC1B loss could be rescued by the intact human ARPC1B ortholog, but not by the p.V208VfsX20 variant identified in the patients. Moreover, we found that the expression of ARPC1B is restricted to hematopoietic cells, potentially explaining why a mutation in ARPC1B has now been observed as a cause of WAS, whereas mutations in other, more widely expressed, components of the Arp2/3 complex have not been observed.
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Affiliation(s)
- Raz Somech
- Pediatric Department A and Immunology Service, Jeffrey Modell Foundation Center, Edmond and Lily Safra Children's Hospital, Sheba Medical Center, Tel Hashomer, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv 52621, Israel.,The Wohl Institute for Translational Medicine, Sheba Medical Center, Tel Hashomer, Tel Aviv 52621, Israel
| | - Atar Lev
- Pediatric Department A and Immunology Service, Jeffrey Modell Foundation Center, Edmond and Lily Safra Children's Hospital, Sheba Medical Center, Tel Hashomer, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv 52621, Israel.,The Wohl Institute for Translational Medicine, Sheba Medical Center, Tel Hashomer, Tel Aviv 52621, Israel
| | - Yu Nee Lee
- Pediatric Department A and Immunology Service, Jeffrey Modell Foundation Center, Edmond and Lily Safra Children's Hospital, Sheba Medical Center, Tel Hashomer, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv 52621, Israel.,The Wohl Institute for Translational Medicine, Sheba Medical Center, Tel Hashomer, Tel Aviv 52621, Israel
| | - Amos J Simon
- Pediatric Department A and Immunology Service, Jeffrey Modell Foundation Center, Edmond and Lily Safra Children's Hospital, Sheba Medical Center, Tel Hashomer, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv 52621, Israel.,The Wohl Institute for Translational Medicine, Sheba Medical Center, Tel Hashomer, Tel Aviv 52621, Israel.,Hematology Laboratory, Sheba Medical Center, Tel Hashomer, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv 52621, Israel
| | - Ortal Barel
- The Wohl Institute for Translational Medicine, Sheba Medical Center, Tel Hashomer, Tel Aviv 52621, Israel.,Sheba Cancer Research Center, Sheba Medical Center, Tel Hashomer, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv 52621, Israel
| | - Ginette Schiby
- Department of Pathology, Sheba Medical Center, Tel Hashomer, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv 52621, Israel
| | - Camila Avivi
- Department of Pathology, Sheba Medical Center, Tel Hashomer, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv 52621, Israel
| | - Iris Barshack
- Department of Pathology, Sheba Medical Center, Tel Hashomer, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv 52621, Israel
| | - Michele Rhodes
- Blood Cell Development and Function Program, Fox Chase Cancer Center, Philadelphia, PA 19111
| | - Jiejing Yin
- Blood Cell Development and Function Program, Fox Chase Cancer Center, Philadelphia, PA 19111
| | - Minshi Wang
- Blood Cell Development and Function Program, Fox Chase Cancer Center, Philadelphia, PA 19111
| | - Yibin Yang
- Blood Cell Development and Function Program, Fox Chase Cancer Center, Philadelphia, PA 19111
| | - Jennifer Rhodes
- Blood Cell Development and Function Program, Fox Chase Cancer Center, Philadelphia, PA 19111
| | - Nufar Marcus
- Allergy and Immunology Unit, Schneider Children's Medical Center of Israel, Felsenstein Medical Research Center, Kipper Institute of Immunology, Petach Tikva, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv 4920235, Israel
| | - Ben-Zion Garty
- Allergy and Immunology Unit, Schneider Children's Medical Center of Israel, Felsenstein Medical Research Center, Kipper Institute of Immunology, Petach Tikva, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv 4920235, Israel
| | - Jerry Stein
- Bone Marrow Transplantation Unit, Schneider Children's Medical Center of Israel, Petach Tikva, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv 4920235, Israel; and
| | - Ninette Amariglio
- The Wohl Institute for Translational Medicine, Sheba Medical Center, Tel Hashomer, Tel Aviv 52621, Israel.,Hematology Laboratory, Sheba Medical Center, Tel Hashomer, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv 52621, Israel.,Sheba Cancer Research Center, Sheba Medical Center, Tel Hashomer, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv 52621, Israel.,The Mina and Everard Goodman Faculty of Life Sciences, Bar-Ilan University, Ramat Gan 52900, Israel
| | - Gideon Rechavi
- The Wohl Institute for Translational Medicine, Sheba Medical Center, Tel Hashomer, Tel Aviv 52621, Israel.,Sheba Cancer Research Center, Sheba Medical Center, Tel Hashomer, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv 52621, Israel
| | - David L Wiest
- Blood Cell Development and Function Program, Fox Chase Cancer Center, Philadelphia, PA 19111;
| | - Yong Zhang
- Blood Cell Development and Function Program, Fox Chase Cancer Center, Philadelphia, PA 19111;
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15
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Abstract
Actin reorganization regulates key processes in platelet activation. Here we examined the role of the Arp2/3 complex, an essential component in actin filament branching, in platelet function. The Arpc2 gene, encoding the p34 subunit of the Arp2/3 complex, was deleted in the megakaryocyte lineage (Arpc2fl/flPF4-Cre). Deletion of the Arp2/3 complex resulted in marked microthrombocytopenia in mice, caused by premature platelet release into the bone marrow compartment and impaired platelet survival in circulation. Arpc2fl/flPF4-Cre platelets exhibited alterations in their actin cytoskeleton and their peripheral microtubule coil. Thrombocytopenia was alleviated following clodronate liposome-induced macrophage depletion in Arpc2fl/flPF4-Cre mice. Arpc2fl/flPF4-Cre platelets failed to spread and showed a mild defect in integrin activation and aggregation. However, no significant differences in hemostasis or thrombosis were observed between Arpc2fl/flPF4-Cre and control mice. Thus, Arp2/3 is critical for platelet homeostasis but plays only a minor role for vascular hemostasis.
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16
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Loss of the Arp2/3 complex component ARPC1B causes platelet abnormalities and predisposes to inflammatory disease. Nat Commun 2017. [PMID: 28368018 DOI: 10.1038/ncomms14816)] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/04/2022] Open
Abstract
Human actin-related protein 2/3 complex (Arp2/3), required for actin filament branching, has two ARPC1 component isoforms, with ARPC1B prominently expressed in blood cells. Here we show in a child with microthrombocytopenia, eosinophilia and inflammatory disease, a homozygous frameshift mutation in ARPC1B (p.Val91Trpfs*30). Platelet lysates reveal no ARPC1B protein and greatly reduced Arp2/3 complex. Missense ARPC1B mutations are identified in an unrelated patient with similar symptoms and ARPC1B deficiency. ARPC1B-deficient platelets are microthrombocytes similar to those seen in Wiskott-Aldrich syndrome that show aberrant spreading consistent with loss of Arp2/3 function. Knockout of ARPC1B in megakaryocytic cells results in decreased proplatelet formation, and as observed in platelets from patients, increased ARPC1A expression. Thus loss of ARPC1B produces a unique set of platelet abnormalities, and is associated with haematopoietic/immune symptoms affecting cell lineages where this isoform predominates. In agreement with recent experimental studies, our findings suggest that ARPC1 isoforms are not functionally interchangeable.
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17
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Kahr WHA, Pluthero FG, Elkadri A, Warner N, Drobac M, Chen CH, Lo RW, Li L, Li R, Li Q, Thoeni C, Pan J, Leung G, Lara-Corrales I, Murchie R, Cutz E, Laxer RM, Upton J, Roifman CM, Yeung RSM, Brumell JH, Muise AM. Loss of the Arp2/3 complex component ARPC1B causes platelet abnormalities and predisposes to inflammatory disease. Nat Commun 2017; 8:14816. [PMID: 28368018 PMCID: PMC5382316 DOI: 10.1038/ncomms14816] [Citation(s) in RCA: 147] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2016] [Accepted: 01/31/2017] [Indexed: 12/19/2022] Open
Abstract
Human actin-related protein 2/3 complex (Arp2/3), required for actin filament branching, has two ARPC1 component isoforms, with ARPC1B prominently expressed in blood cells. Here we show in a child with microthrombocytopenia, eosinophilia and inflammatory disease, a homozygous frameshift mutation in ARPC1B (p.Val91Trpfs*30). Platelet lysates reveal no ARPC1B protein and greatly reduced Arp2/3 complex. Missense ARPC1B mutations are identified in an unrelated patient with similar symptoms and ARPC1B deficiency. ARPC1B-deficient platelets are microthrombocytes similar to those seen in Wiskott–Aldrich syndrome that show aberrant spreading consistent with loss of Arp2/3 function. Knockout of ARPC1B in megakaryocytic cells results in decreased proplatelet formation, and as observed in platelets from patients, increased ARPC1A expression. Thus loss of ARPC1B produces a unique set of platelet abnormalities, and is associated with haematopoietic/immune symptoms affecting cell lineages where this isoform predominates. In agreement with recent experimental studies, our findings suggest that ARPC1 isoforms are not functionally interchangeable. ARPC1B is a component of the actin-related protein 2/3 complex (Arp2/3), which is required for actin filament branching. Kahr et al. show that ARPC1B deficiency in humans is associated with severe multisystem disease that includes platelet abnormalities, eosinophilia, eczema and other indicators of immune disease.
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Affiliation(s)
- Walter H A Kahr
- Cell Biology Program, Research Institute, Hospital for Sick Children, Toronto, Ontario, Canada M5G 0A4.,Division of Haematology/Oncology, Department of Paediatrics, University of Toronto and The Hospital for Sick Children, Toronto, Ontario, Canada M5G 1X8.,Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada M5S 1A8
| | - Fred G Pluthero
- Cell Biology Program, Research Institute, Hospital for Sick Children, Toronto, Ontario, Canada M5G 0A4
| | - Abdul Elkadri
- Cell Biology Program, Research Institute, Hospital for Sick Children, Toronto, Ontario, Canada M5G 0A4.,SickKids Inflammatory Bowel Disease Center and Division of Gastroenterology, Hepatology, and Nutrition, Department of Paediatrics, University of Toronto, Hospital for Sick Children, Toronto, Ontario, Canada M5G 1X8.,Institute of Medical Science, University of Toronto, Toronto, Ontario, Canada M5S 1A8
| | - Neil Warner
- Cell Biology Program, Research Institute, Hospital for Sick Children, Toronto, Ontario, Canada M5G 0A4.,SickKids Inflammatory Bowel Disease Center and Division of Gastroenterology, Hepatology, and Nutrition, Department of Paediatrics, University of Toronto, Hospital for Sick Children, Toronto, Ontario, Canada M5G 1X8
| | - Marko Drobac
- Cell Biology Program, Research Institute, Hospital for Sick Children, Toronto, Ontario, Canada M5G 0A4.,Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada M5S 1A8
| | - Chang Hua Chen
- Cell Biology Program, Research Institute, Hospital for Sick Children, Toronto, Ontario, Canada M5G 0A4.,Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada M5S 1A8
| | - Richard W Lo
- Cell Biology Program, Research Institute, Hospital for Sick Children, Toronto, Ontario, Canada M5G 0A4.,Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada M5S 1A8
| | - Ling Li
- Cell Biology Program, Research Institute, Hospital for Sick Children, Toronto, Ontario, Canada M5G 0A4
| | - Ren Li
- Cell Biology Program, Research Institute, Hospital for Sick Children, Toronto, Ontario, Canada M5G 0A4
| | - Qi Li
- Cell Biology Program, Research Institute, Hospital for Sick Children, Toronto, Ontario, Canada M5G 0A4.,SickKids Inflammatory Bowel Disease Center and Division of Gastroenterology, Hepatology, and Nutrition, Department of Paediatrics, University of Toronto, Hospital for Sick Children, Toronto, Ontario, Canada M5G 1X8
| | - Cornelia Thoeni
- Cell Biology Program, Research Institute, Hospital for Sick Children, Toronto, Ontario, Canada M5G 0A4.,SickKids Inflammatory Bowel Disease Center and Division of Gastroenterology, Hepatology, and Nutrition, Department of Paediatrics, University of Toronto, Hospital for Sick Children, Toronto, Ontario, Canada M5G 1X8
| | - Jie Pan
- Cell Biology Program, Research Institute, Hospital for Sick Children, Toronto, Ontario, Canada M5G 0A4.,SickKids Inflammatory Bowel Disease Center and Division of Gastroenterology, Hepatology, and Nutrition, Department of Paediatrics, University of Toronto, Hospital for Sick Children, Toronto, Ontario, Canada M5G 1X8
| | - Gabriella Leung
- Cell Biology Program, Research Institute, Hospital for Sick Children, Toronto, Ontario, Canada M5G 0A4.,SickKids Inflammatory Bowel Disease Center and Division of Gastroenterology, Hepatology, and Nutrition, Department of Paediatrics, University of Toronto, Hospital for Sick Children, Toronto, Ontario, Canada M5G 1X8
| | - Irene Lara-Corrales
- Division of Pathology, The Hospital for Sick Children, Toronto, Ontario, Canada M5G 1X8
| | - Ryan Murchie
- Cell Biology Program, Research Institute, Hospital for Sick Children, Toronto, Ontario, Canada M5G 0A4.,SickKids Inflammatory Bowel Disease Center and Division of Gastroenterology, Hepatology, and Nutrition, Department of Paediatrics, University of Toronto, Hospital for Sick Children, Toronto, Ontario, Canada M5G 1X8
| | - Ernest Cutz
- Division of Pathology, The Hospital for Sick Children, Toronto, Ontario, Canada M5G 1X8
| | - Ronald M Laxer
- Division of Rheumatology, Department of Paediatrics, University of Toronto, The Hospital for Sick Children, Toronto, Ontario, Canada M5G 1X8.,Department of Medicine, University of Toronto, Toronto, Ontario, Canada M5S 1A8
| | - Julia Upton
- Division of Immunology, Department of Paediatrics, University of Toronto, The Hospital for Sick Children, Toronto, Ontario, Canada M5G 1X8
| | - Chaim M Roifman
- Division of Immunology, Department of Paediatrics, University of Toronto, The Hospital for Sick Children, Toronto, Ontario, Canada M5G 1X8
| | - Rae S M Yeung
- Cell Biology Program, Research Institute, Hospital for Sick Children, Toronto, Ontario, Canada M5G 0A4.,Institute of Medical Science, University of Toronto, Toronto, Ontario, Canada M5S 1A8.,Division of Rheumatology, Department of Paediatrics, University of Toronto, The Hospital for Sick Children, Toronto, Ontario, Canada M5G 1X8.,Department of Immunology, University of Toronto, Toronto, Ontario, Canada M5S 1A8
| | - John H Brumell
- Cell Biology Program, Research Institute, Hospital for Sick Children, Toronto, Ontario, Canada M5G 0A4.,SickKids Inflammatory Bowel Disease Center and Division of Gastroenterology, Hepatology, and Nutrition, Department of Paediatrics, University of Toronto, Hospital for Sick Children, Toronto, Ontario, Canada M5G 1X8.,Institute of Medical Science, University of Toronto, Toronto, Ontario, Canada M5S 1A8.,Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada M5S 1A8
| | - Aleixo M Muise
- Cell Biology Program, Research Institute, Hospital for Sick Children, Toronto, Ontario, Canada M5G 0A4.,Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada M5S 1A8.,SickKids Inflammatory Bowel Disease Center and Division of Gastroenterology, Hepatology, and Nutrition, Department of Paediatrics, University of Toronto, Hospital for Sick Children, Toronto, Ontario, Canada M5G 1X8.,Institute of Medical Science, University of Toronto, Toronto, Ontario, Canada M5S 1A8
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18
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Xiao Y, Ma H, Wan P, Qin D, Wang X, Zhang X, Xiang Y, Liu W, Chen J, Yi Z, Li L. Trp-Asp (WD) Repeat Domain 1 Is Essential for Mouse Peri-implantation Development and Regulates Cofilin Phosphorylation. J Biol Chem 2016; 292:1438-1448. [PMID: 27994054 DOI: 10.1074/jbc.m116.759886] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2016] [Revised: 12/16/2016] [Indexed: 01/18/2023] Open
Abstract
Trp-Asp (WD) repeat domain 1 (WDR1) is a highly conserved actin-binding protein across all eukaryotes and is involved in numerous actin-based processes by accelerating Cofilin severing actin filament. However, the function and the mechanism of WDR1 in mammalian early development are still largely unclear. We now report that WDR1 is essential for mouse peri-implantation development and regulates Cofilin phosphorylation in mouse cells. The disruption of maternal WDR1 does not obviously affect ovulation and female fertility. However, depletion of zygotic WDR1 results in embryonic lethality at the peri-implantation stage. In WDR1 knock-out cells, we found that WDR1 regulates Cofilin phosphorylation. Interestingly, WDR1 is overdosed to regulate Cofilin phosphorylation in mouse cells. Furthermore, we showed that WDR1 interacts with Lim domain kinase 1 (LIMK1), a well known phosphorylation kinase of Cofilin. Altogether, our results provide new insights into the role and mechanism of WDR1 in physiological conditions.
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Affiliation(s)
- Yi Xiao
- From the State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, 100101 Beijing.,the Institute of Zoology, University of Chinese Academy of Sciences, Beijing 100049
| | - Haixia Ma
- From the State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, 100101 Beijing.,the Institute of Zoology, University of Chinese Academy of Sciences, Beijing 100049
| | - Ping Wan
- the State Key Laboratory of Pharmaceutical Biotechnology and MOE Key Laboratory of Model Animals for Disease Study, Model Animal Research Center, Nanjing University, Nanjing 210061, and
| | - Dandan Qin
- From the State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, 100101 Beijing.,the Institute of Zoology, University of Chinese Academy of Sciences, Beijing 100049
| | - Xiaoxiao Wang
- From the State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, 100101 Beijing.,the Institute of Zoology, University of Chinese Academy of Sciences, Beijing 100049
| | - Xiaoxin Zhang
- From the State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, 100101 Beijing
| | - Yunlong Xiang
- From the State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, 100101 Beijing
| | - Wenbo Liu
- From the State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, 100101 Beijing
| | - Jiong Chen
- the State Key Laboratory of Pharmaceutical Biotechnology and MOE Key Laboratory of Model Animals for Disease Study, Model Animal Research Center, Nanjing University, Nanjing 210061, and
| | - Zhaohong Yi
- the Key Laboratory of Urban Agriculture (North) of Ministry of Agriculture, College of Biological Science and Engineering, Beijing University of Agriculture, Beijing 102206, China
| | - Lei Li
- From the State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, 100101 Beijing, .,the Institute of Zoology, University of Chinese Academy of Sciences, Beijing 100049
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19
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Kuijpers TW, Tool ATJ, van der Bijl I, de Boer M, van Houdt M, de Cuyper IM, Roos D, van Alphen F, van Leeuwen K, Cambridge EL, Arends MJ, Dougan G, Clare S, Ramirez-Solis R, Pals ST, Adams DJ, Meijer AB, van den Berg TK. Combined immunodeficiency with severe inflammation and allergy caused by ARPC1B deficiency. J Allergy Clin Immunol 2016; 140:273-277.e10. [PMID: 27965109 DOI: 10.1016/j.jaci.2016.09.061] [Citation(s) in RCA: 94] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2016] [Revised: 09/09/2016] [Accepted: 09/22/2016] [Indexed: 12/19/2022]
Affiliation(s)
- Taco W Kuijpers
- Department of Pediatric Hematology, Immunology and Infectious Diseases, Emma Children's Hospital, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands; Department of Blood Cell Research, Sanquin Research, University of Amsterdam, Amsterdam, The Netherlands.
| | - Anton T J Tool
- Department of Blood Cell Research, Sanquin Research, University of Amsterdam, Amsterdam, The Netherlands
| | - Ivo van der Bijl
- Department of Blood Cell Research, Sanquin Research, University of Amsterdam, Amsterdam, The Netherlands
| | - Martin de Boer
- Department of Blood Cell Research, Sanquin Research, University of Amsterdam, Amsterdam, The Netherlands
| | - Michel van Houdt
- Department of Blood Cell Research, Sanquin Research, University of Amsterdam, Amsterdam, The Netherlands
| | - Iris M de Cuyper
- Department of Blood Cell Research, Sanquin Research, University of Amsterdam, Amsterdam, The Netherlands
| | - Dirk Roos
- Department of Blood Cell Research, Sanquin Research, University of Amsterdam, Amsterdam, The Netherlands
| | - Floris van Alphen
- Department of Plasma Proteins, Sanquin Research, University of Amsterdam, Amsterdam, The Netherlands
| | - Karin van Leeuwen
- Department of Blood Cell Research, Sanquin Research, University of Amsterdam, Amsterdam, The Netherlands
| | - Emma L Cambridge
- Wellcome Trust Sanger Institute, Hinxton, Cambridgeshire, United Kingdom
| | - Mark J Arends
- Division of Pathology, Centre for Comparative Pathology, Edinburgh Cancer Research Centre, Institute of Genetics and Molecular Medicine, Western General Hospital, University of Edinburgh, Edinburgh, United Kingdom
| | - Gordon Dougan
- Wellcome Trust Sanger Institute, Hinxton, Cambridgeshire, United Kingdom
| | - Simon Clare
- Wellcome Trust Sanger Institute, Hinxton, Cambridgeshire, United Kingdom
| | | | - Steven T Pals
- Department of Pathology, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - David J Adams
- Wellcome Trust Sanger Institute, Hinxton, Cambridgeshire, United Kingdom
| | - Alexander B Meijer
- Department of Plasma Proteins, Sanquin Research, University of Amsterdam, Amsterdam, The Netherlands
| | - Timo K van den Berg
- Department of Blood Cell Research, Sanquin Research, University of Amsterdam, Amsterdam, The Netherlands
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20
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Wang PS, Chou FS, Ramachandran S, Xia S, Chen HY, Guo F, Suraneni P, Maher BJ, Li R. Crucial roles of the Arp2/3 complex during mammalian corticogenesis. Development 2016; 143:2741-52. [PMID: 27385014 PMCID: PMC5004905 DOI: 10.1242/dev.130542] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2015] [Accepted: 06/20/2016] [Indexed: 02/06/2023]
Abstract
The polarity and organization of radial glial cells (RGCs), which serve as both stem cells and scaffolds for neuronal migration, are crucial for cortical development. However, the cytoskeletal mechanisms that drive radial glial outgrowth and maintain RGC polarity remain poorly understood. Here, we show that the Arp2/3 complex – the unique actin nucleator that produces branched actin networks – plays essential roles in RGC polarity and morphogenesis. Disruption of the Arp2/3 complex in murine RGCs retards process outgrowth toward the basal surface and impairs apical polarity and adherens junctions. Whereas the former is correlated with an abnormal actin-based leading edge, the latter is consistent with blockage in membrane trafficking. These defects result in altered cell fate, disrupted cortical lamination and abnormal angiogenesis. In addition, we present evidence that the Arp2/3 complex is a cell-autonomous regulator of neuronal migration. Our data suggest that Arp2/3-mediated actin assembly might be particularly important for neuronal cell motility in a soft or poorly adhesive matrix environment. Summary: During mouse cortical development, the Arp2/3 actin branching complex regulates process formation and the maintenance of radial glial cell polarity, as well as affecting neuronal migration.
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Affiliation(s)
- Pei-Shan Wang
- Stowers Institute for Medical Research, 1000 East 50th Street, Kansas City, MO 64110, USA
| | - Fu-Sheng Chou
- Division of Newborn Medicine, Boston Children's Hospital, Harvard Medical School, 300 Longwood Ave., Boston, MA 02115, USA
| | - Sreekumar Ramachandran
- Department of Cell Biology, Johns Hopkins University School of Medicine, 855 North Wolfe Street, Baltimore, MD 21205, USA
| | - Sheng Xia
- Department of Cell Biology, Johns Hopkins University School of Medicine, 855 North Wolfe Street, Baltimore, MD 21205, USA
| | - Huei-Ying Chen
- Lieber Institute for Brain Development, 855 North Wolfe Street, Baltimore, MD 21205, USA
| | - Fengli Guo
- Stowers Institute for Medical Research, 1000 East 50th Street, Kansas City, MO 64110, USA
| | - Praveen Suraneni
- Division of Hematology/Oncology, Robert Lurie Comprehensive Cancer Center, Department of Medicine, Northwestern University, Chicago, IL 60611, USA
| | - Brady J Maher
- Lieber Institute for Brain Development, 855 North Wolfe Street, Baltimore, MD 21205, USA Department of Psychiatry and Behavioral Sciences, Johns Hopkins School of Medicine, 4940 Eastern Ave., Baltimore, MD 21224, USA Department of Neuroscience, Johns Hopkins School of Medicine, 725 N. Wolfe St., Baltimore, MD 21205, USA
| | - Rong Li
- Stowers Institute for Medical Research, 1000 East 50th Street, Kansas City, MO 64110, USA Department of Cell Biology, Johns Hopkins University School of Medicine, 855 North Wolfe Street, Baltimore, MD 21205, USA Department of Chemical and Biomolecular Engineering, Johns Hopkins University, 3400 N Charles St., Baltimore, MD 21218, USA
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21
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Swaney KF, Li R. Function and regulation of the Arp2/3 complex during cell migration in diverse environments. Curr Opin Cell Biol 2016; 42:63-72. [PMID: 27164504 DOI: 10.1016/j.ceb.2016.04.005] [Citation(s) in RCA: 65] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2016] [Accepted: 04/11/2016] [Indexed: 02/06/2023]
Abstract
As the first de novo actin nucleator discovered, the Arp2/3 complex has been a central player in models of protrusive force production via the dynamic actin network. Here, we review recent studies on the functional role of the Arp2/3 complex in the migration of diverse cell types in different migratory environments. These findings have revealed an unexpected level of plasticity, both in how cells rely on the Arp2/3 complex for migration and other physiological functions and in the intricate modulation of the Arp2/3 complex by other actin regulators and upstream signaling cascades.
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Affiliation(s)
- Kristen F Swaney
- Department of Cell Biology, Johns Hopkins University School of Medicine, 855 North Wolfe Street, 450 Rangos Building, Baltimore, MD 21205, USA; Department of Chemical and Biomolecular Engineering, Whiting School of Engineering, Johns Hopkins University, 3400 North Charles Street, 100 Croft Hall, Baltimore, MD 21218, USA.
| | - Rong Li
- Department of Cell Biology, Johns Hopkins University School of Medicine, 855 North Wolfe Street, 450 Rangos Building, Baltimore, MD 21205, USA; Department of Chemical and Biomolecular Engineering, Whiting School of Engineering, Johns Hopkins University, 3400 North Charles Street, 100 Croft Hall, Baltimore, MD 21218, USA
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22
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Zuchero JB, Fu MM, Sloan SA, Ibrahim A, Olson A, Zaremba A, Dugas JC, Wienbar S, Caprariello AV, Kantor C, Leonoudakis D, Leonoudakus D, Lariosa-Willingham K, Kronenberg G, Gertz K, Soderling SH, Miller RH, Barres BA. CNS myelin wrapping is driven by actin disassembly. Dev Cell 2015; 34:152-67. [PMID: 26166300 PMCID: PMC4519368 DOI: 10.1016/j.devcel.2015.06.011] [Citation(s) in RCA: 227] [Impact Index Per Article: 25.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2015] [Revised: 05/18/2015] [Accepted: 06/11/2015] [Indexed: 12/15/2022]
Abstract
Myelin is essential in vertebrates for the rapid propagation of action potentials, but the molecular mechanisms driving its formation remain largely unknown. Here we show that the initial stage of process extension and axon ensheathment by oligodendrocytes requires dynamic actin filament assembly by the Arp2/3 complex. Unexpectedly, subsequent myelin wrapping coincides with the upregulation of actin disassembly proteins and rapid disassembly of the oligodendrocyte actin cytoskeleton and does not require Arp2/3. Inducing loss of actin filaments drives oligodendrocyte membrane spreading and myelin wrapping in vivo, and the actin disassembly factor gelsolin is required for normal wrapping. We show that myelin basic protein, a protein essential for CNS myelin wrapping whose role has been unclear, is required for actin disassembly, and its loss phenocopies loss of actin disassembly proteins. Together, these findings provide insight into the molecular mechanism of myelin wrapping and identify it as an actin-independent form of mammalian cell motility.
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Affiliation(s)
- J Bradley Zuchero
- Department of Neurobiology, Stanford University School of Medicine, Stanford, CA 94305, USA.
| | - Meng-Meng Fu
- Department of Neurobiology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Steven A Sloan
- Department of Neurobiology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Adiljan Ibrahim
- Department of Neurobiology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Andrew Olson
- Department of Neurosurgery, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Anita Zaremba
- Department of Neurosciences, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA
| | | | - Sophia Wienbar
- Department of Neurobiology, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Andrew V Caprariello
- Department of Neurosciences, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA
| | - Christopher Kantor
- Department of Neurosciences, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA
| | | | | | | | - Golo Kronenberg
- Klinik für Psychiatrie und Psychotherapie, Charité-Universitätsmedizin Berlin, Charité Campus Mitte, 10117 Berlin, Germany; Klinik und Poliklinik für Neurologie, Charité-Universitätsmedizin Berlin, Charitéplatz 1, 10117 Berlin, Germany
| | - Karen Gertz
- Klinik und Poliklinik für Neurologie, Charité-Universitätsmedizin Berlin, Charitéplatz 1, 10117 Berlin, Germany
| | - Scott H Soderling
- Departments of Cell Biology and Neurobiology, Duke University Medical School, Durham, NC 27710, USA
| | - Robert H Miller
- Department of Neurosciences, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA
| | - Ben A Barres
- Department of Neurobiology, Stanford University School of Medicine, Stanford, CA 94305, USA
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Abstract
Rho GTPases are critical for platelet function. Although the roles of RhoA, Rac and Cdc42 are characterized, platelets express other Rho GTPases, whose activities are less well understood. This review summarizes our understanding of the roles of platelet Rho GTPases and focuses particularly on the functions of Rif and RhoG. In human platelets, Rif interacts with cytoskeleton regulators including formins mDia1 and mDia3, whereas RhoG binds SNARE-complex proteins and cytoskeletal regulators ELMO and DOCK1. Knockout mouse studies suggest that Rif plays no critical functions in platelets, likely due to functional overlap with other Rho GTPases. In contrast, RhoG is essential for normal granule secretion downstream of the collagen receptor GPVI. The central defect in RhoG-/- platelets is reduced dense granule secretion, which impedes integrin activation and aggregation and limits platelet recruitment to growing thrombi under shear, translating into reduced thrombus formation in vivo. Potential avenues for future work on Rho GTPases in platelets are also highlighted, including identification of the key regulator for platelet filopodia formation and investigation of the role of the many Rho GTPase regulators in platelet function in both health and disease.
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24
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Abstract
The importance of the cytoskeleton in mounting a successful immune response is evident from the wide range of defects that occur in actin-related primary immunodeficiencies (PIDs). Studies of these PIDs have revealed a pivotal role for the actin cytoskeleton in almost all stages of immune system function, from hematopoiesis and immune cell development, through to recruitment, migration, intercellular and intracellular signaling, and activation of both innate and adaptive immune responses. The major focus of this review is the immune defects that result from mutations in the Wiskott-Aldrich syndrome gene (WAS), which have a broad impact on many different processes and give rise to clinically heterogeneous immunodeficiencies. We also discuss other related genetic defects and the possibility of identifying new genetic causes of cytoskeletal immunodeficiency.
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Affiliation(s)
- Dale A Moulding
- Molecular Immunology Unit, Center for Immunodeficiency, Institute of Child Health, University College London, London, UK
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25
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Sun SC, Wang QL, Gao WW, Xu YN, Liu HL, Cui XS, Kim NH. Actin nucleator Arp2/3 complex is essential for mouse preimplantation embryo development. Reprod Fertil Dev 2013; 25:617-23. [PMID: 22951093 DOI: 10.1071/rd12011] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2012] [Accepted: 05/15/2012] [Indexed: 12/15/2022] Open
Abstract
The Arp2/3 complex is a critical actin nucleator, which promotes actin assembly and is widely involved in a diverse range of actin-related processes such as cell locomotion, phagocytosis and the establishment of cell polarity. Previous studies showed that the Arp2/3 complex regulates spindle migration and asymmetric division during mouse oocyte maturation; however, the role of the Arp2/3 complex in early mouse embryo development is still unknown. The results of the present study show that the Arp2/3 complex is critical for cytokinesis during mouse embryo development. The Arp2/3 complex was concentrated at the cortex of each cell at the 2- to 8-cell stage and the peripheral areas of the morula and blastocyst. Inhibition of the Arp2/3 complex by the specific inhibitor CK666 at the zygote stage caused a failure in cell division; mouse embryos failed to undergo compaction and lost apical-basal polarity. The actin level decreased in the CK666-treated group, and two or more nuclei were observed within a single cell, indicating a failure of cell division. Addition of CK666 at the 8-cell stage caused a failure of blastocyst formation, and CDX2 staining confirmed the loss of embryo polarity and the failure of trophectoderm and inner cell mass formation. Taken together, these data suggest that the Arp2/3 complex may regulate mouse embryo development via its effect on cell division.
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Affiliation(s)
- Shao-Chen Sun
- Department of Animal Sciences, Chungbuk National University, Cheongju 361-763, Korea
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26
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Disruption of Arp2/3 results in asymmetric structural plasticity of dendritic spines and progressive synaptic and behavioral abnormalities. J Neurosci 2013; 33:6081-92. [PMID: 23554489 DOI: 10.1523/jneurosci.0035-13.2013] [Citation(s) in RCA: 128] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Despite evidence for a strong genetic contribution to several major psychiatric disorders, individual candidate genes account for only a small fraction of these disorders, leading to the suggestion that multigenetic pathways may be involved. Several known genetic risk factors for psychiatric disease are related to the regulation of actin polymerization, which plays a key role in synaptic plasticity. To gain insight into and test the possible pathogenetic role of this pathway, we designed a conditional knock-out of the Arp2/3 complex, a conserved final output for actin signaling pathways that orchestrates de novo actin polymerization. Here we report that postnatal loss of the Arp2/3 subunit ArpC3 in forebrain excitatory neurons leads to an asymmetric structural plasticity of dendritic spines, followed by a progressive loss of spine synapses. This progression of synaptic deficits corresponds with an evolution of distinct cognitive, psychomotor, and social disturbances as the mice age. Together, these results point to the dysfunction of actin signaling, specifically that which converges to regulate Arp2/3, as an important cellular pathway that may contribute to the etiology of complex psychiatric disorders.
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Bryce NS, Reynolds AB, Koleske AJ, Weaver AM. WAVE2 regulates epithelial morphology and cadherin isoform switching through regulation of Twist and Abl. PLoS One 2013; 8:e64533. [PMID: 23691243 PMCID: PMC3654908 DOI: 10.1371/journal.pone.0064533] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2011] [Accepted: 04/16/2013] [Indexed: 12/17/2022] Open
Abstract
Background Epithelial morphogenesis is a dynamic process that involves coordination of signaling and actin cytoskeletal rearrangements. Principal Findings We analyzed the contribution of the branched actin regulator WAVE2 in the development of 3-dimensional (3D) epithelial structures. WAVE2-knockdown (WAVE2-KD) cells formed large multi-lobular acini that continued to proliferate at an abnormally late stage compared to control acini. Immunostaining of the cell-cell junctions of WAVE2-KD acini revealed weak and heterogeneous E-cadherin staining despite little change in actin filament localization to the same junctions. Analysis of cadherin expression demonstrated a decrease in E-cadherin and an increase in N-cadherin protein and mRNA abundance in total cell lysates. In addition, WAVE2-KD cells exhibited an increase in the mRNA levels of the epithelial-mesenchymal transition (EMT)-associated transcription factor Twist1. KD of Twist1 expression in WAVE2-KD cells reversed the cadherin switching and completely rescued the aberrant 3D morphological phenotype. Activity of the WAVE2 complex binding partner Abl kinase was also increased in WAVE2-KD cells, as assessed by tyrosine phosphorylation of the Abl substrate CrkL. Inhibition of Abl with STI571 rescued the multi-lobular WAVE2-KD 3D phenotype whereas overexpression of Abl kinase phenocopied the WAVE2-KD phenotype. Conclusions The WAVE2 complex regulates breast epithelial morphology by a complex mechanism involving repression of Twist1 expression and Abl kinase activity. These data reveal a critical role for WAVE2 complex in regulation of cellular signaling and epithelial morphogenesis.
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Affiliation(s)
- Nicole S Bryce
- Department of Cancer Biology, Vanderbilt University Medical Center, Nashville, Tennessee, United States of America
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28
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Guo L, Tsai SQ, Hardison NE, James AH, Motsinger-Reif AA, Thames B, Stone EA, Deng C, Piedrahita JA. Differentially expressed microRNAs and affected biological pathways revealed by modulated modularity clustering (MMC) analysis of human preeclamptic and IUGR placentas. Placenta 2013; 34:599-605. [PMID: 23639576 DOI: 10.1016/j.placenta.2013.04.007] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/05/2012] [Revised: 03/25/2013] [Accepted: 04/05/2013] [Indexed: 01/12/2023]
Abstract
INTRODUCTION This study focuses on the implementation of modulated modularity clustering (MMC) a new cluster algorithm for the identification of molecular signatures of preeclampsia and intrauterine growth restriction (IUGR), and the identification of affected microRNAs METHODS Eighty-six human placentas from normal (40), growth-restricted (27), and preeclamptic (19) term pregnancies were profiled using Illumina Human-6 Beadarrays. MMC was utilized to generate modules based on similarities in placental transcriptome. Gene Set Enrichment Analysis (GSEA) was used to predict affected microRNAs. Expression levels of these candidate microRNAs were investigated in seventy-one human term placentas as follows: control (29); IUGR (26); and preeclampsia (16). RESULTS MMC identified two modules, one representing IUGR placentas and one representing preeclamptic placentas. 326 differentially expressed genes in the module representing IUGR and 889 differentially expressed genes in a module representing preeclampsia were identified. Functional analysis of molecular signatures associated with IUGR identified P13K/AKT, mTOR, p70S6K, apoptosis and IGF-1 signaling as being affected. Analysis of variance of GSEA-predicted microRNAs indicated that miR-194 was significantly down-regulated both in preeclampsia (p = 0.0001) and IUGR (p = 0.0304), and miR-149 was significantly down-regulated in preeclampsia (p = 0.0168). DISCUSSION Implementation of MMC, allowed identification of genes disregulated in IUGR and preeclampsia. The reliability of MMC was validated by comparing to previous linear modeling analysis of preeclamptic placentas. CONCLUSION MMC allowed the elucidation of a molecular signature associated with preeclampsia and a subset of IUGR samples. This allowed the identification of genes, pathways, and microRNAs affected in these diseases.
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Affiliation(s)
- L Guo
- Department of Molecular Biomedical Sciences, College of Veterinary Medicine, North Carolina State University, Raleigh, NC, USA
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29
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Rotty JD, Wu C, Bear JE. New insights into the regulation and cellular functions of the ARP2/3 complex. Nat Rev Mol Cell Biol 2012; 14:7-12. [DOI: 10.1038/nrm3492] [Citation(s) in RCA: 359] [Impact Index Per Article: 29.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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30
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Suraneni P, Rubinstein B, Unruh JR, Durnin M, Hanein D, Li R. The Arp2/3 complex is required for lamellipodia extension and directional fibroblast cell migration. ACTA ACUST UNITED AC 2012; 197:239-51. [PMID: 22492726 PMCID: PMC3328382 DOI: 10.1083/jcb.201112113] [Citation(s) in RCA: 266] [Impact Index Per Article: 22.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Embryonic stem cell–derived fibroblasts with genetic disruption of the Arp2/3 complex are unable to form lamellipodia or undergo sustained directional migration. The Arp2/3 complex nucleates the formation of the dendritic actin network at the leading edge of motile cells, but it is still unclear if the Arp2/3 complex plays a critical role in lamellipodia protrusion and cell motility. Here, we differentiated motile fibroblast cells from isogenic mouse embryonic stem cells with or without disruption of the ARPC3 gene, which encodes the p21 subunit of the Arp2/3 complex. ARPC3−/− fibroblasts were unable to extend lamellipodia but generated dynamic leading edges composed primarily of filopodia-like protrusions, with formin proteins (mDia1 and mDia2) concentrated near their tips. The speed of cell migration, as well as the rates of leading edge protrusion and retraction, were comparable between genotypes; however, ARPC3−/− cells exhibited a strong defect in persistent directional migration. This deficiency correlated with a lack of coordination of the protrusive activities at the leading edge of ARPC3−/− fibroblasts. These results provide insights into the Arp2/3 complex’s critical role in lamellipodia extension and directional fibroblast migration.
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Affiliation(s)
- Praveen Suraneni
- Stowers Institute for Medical Research, Kansas City, MO 64110, USA
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31
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Wu C, Asokan SB, Berginski ME, Haynes EM, Sharpless NE, Griffith JD, Gomez SM, Bear JE. Arp2/3 is critical for lamellipodia and response to extracellular matrix cues but is dispensable for chemotaxis. Cell 2012; 148:973-87. [PMID: 22385962 PMCID: PMC3707508 DOI: 10.1016/j.cell.2011.12.034] [Citation(s) in RCA: 371] [Impact Index Per Article: 30.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2011] [Revised: 09/28/2011] [Accepted: 12/21/2011] [Indexed: 02/06/2023]
Abstract
Lamellipodia are sheet-like, leading edge protrusions in firmly adherent cells that contain Arp2/3-generated dendritic actin networks. Although lamellipodia are widely believed to be critical for directional cell motility, this notion has not been rigorously tested. Using fibroblasts derived from Ink4a/Arf-deficient mice, we generated a stable line depleted of Arp2/3 complex that lacks lamellipodia. This line shows defective random cell motility and relies on a filopodia-based protrusion system. Utilizing a microfluidic gradient generation system, we tested the role of Arp2/3 complex and lamellipodia in directional cell migration. Surprisingly, Arp2/3-depleted cells respond normally to shallow gradients of PDGF, indicating that lamellipodia are not required for fibroblast chemotaxis. Conversely, these cells cannot respond to a surface-bound gradient of extracellular matrix (haptotaxis). Consistent with this finding, cells depleted of Arp2/3 fail to globally align focal adhesions, suggesting that one principle function of lamellipodia is to organize cell-matrix adhesions in a spatially coherent manner.
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Affiliation(s)
- Congying Wu
- Dept of Cell & Developmental Biology, University of North Carolina School of Medicine; Chapel Hill, NC 27599 USA
- Lineberger Comprehensive Cancer Center, University of North Carolina School of Medicine; Chapel Hill, NC 27599 USA
| | - Sreeja B. Asokan
- Dept of Cell & Developmental Biology, University of North Carolina School of Medicine; Chapel Hill, NC 27599 USA
- Lineberger Comprehensive Cancer Center, University of North Carolina School of Medicine; Chapel Hill, NC 27599 USA
| | - Matthew E. Berginski
- Depts of Biomedical Engineering, Computer Science and Pharmacology, University of North Carolina School of Medicine; Chapel Hill, NC 27599 USA
| | - Elizabeth M. Haynes
- Dept of Cell & Developmental Biology, University of North Carolina School of Medicine; Chapel Hill, NC 27599 USA
- Lineberger Comprehensive Cancer Center, University of North Carolina School of Medicine; Chapel Hill, NC 27599 USA
| | - Norman E. Sharpless
- Dept of Genetics, University of North Carolina School of Medicine; Chapel Hill, NC 27599 USA
- Lineberger Comprehensive Cancer Center, University of North Carolina School of Medicine; Chapel Hill, NC 27599 USA
| | - Jack D. Griffith
- Lineberger Comprehensive Cancer Center, University of North Carolina School of Medicine; Chapel Hill, NC 27599 USA
- Dept of Biochemistry, University of North Carolina School of Medicine; Chapel Hill, NC 27599 USA
| | - Shawn M. Gomez
- Depts of Biomedical Engineering, Computer Science and Pharmacology, University of North Carolina School of Medicine; Chapel Hill, NC 27599 USA
| | - James E. Bear
- Dept of Cell & Developmental Biology, University of North Carolina School of Medicine; Chapel Hill, NC 27599 USA
- Lineberger Comprehensive Cancer Center, University of North Carolina School of Medicine; Chapel Hill, NC 27599 USA
- Howard Hughes Medical Institute
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Gama Sosa MA, De Gasperi R, Elder GA. Modeling human neurodegenerative diseases in transgenic systems. Hum Genet 2011; 131:535-63. [PMID: 22167414 DOI: 10.1007/s00439-011-1119-1] [Citation(s) in RCA: 83] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2011] [Accepted: 11/23/2011] [Indexed: 02/07/2023]
Abstract
Transgenic systems are widely used to study the cellular and molecular basis of human neurodegenerative diseases. A wide variety of model organisms have been utilized, including bacteria (Escherichia coli), plants (Arabidopsis thaliana), nematodes (Caenorhabditis elegans), arthropods (Drosophila melanogaster), fish (zebrafish, Danio rerio), rodents (mouse, Mus musculus and rat, Rattus norvegicus) as well as non-human primates (rhesus monkey, Macaca mulatta). These transgenic systems have enormous value for understanding the pathophysiological basis of these disorders and have, in some cases, been instrumental in the development of therapeutic approaches to treat these conditions. In this review, we discuss the most commonly used model organisms and the methodologies available for the preparation of transgenic organisms. Moreover, we provide selected examples of the use of these technologies for the preparation of transgenic animal models of neurodegenerative diseases, including Alzheimer's disease (AD), frontotemporal lobar degeneration (FTLD), amyotrophic lateral sclerosis (ALS), Huntington's disease (HD) and Parkinson's disease (PD) and discuss the application of these technologies to AD as an example of how transgenic modeling has affected the study of human neurodegenerative diseases.
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Affiliation(s)
- Miguel A Gama Sosa
- Research and Development Service, James J. Peters Department of Veterans Affairs Medical Center, Bronx, NY 10468, USA.
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33
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Abstract
We describe an experimental approach for generating mutant alleles in rat spermatogonial stem cells (SSCs) using Sleeping Beauty (SB) transposon-mediated insertional mutagenesis. The protocol is based on mobilization of mutagenic gene-trap transposons from transfected plasmid vectors into the genomes of cultured stem cells. Cells with transposon insertions in expressed genes are selected on the basis of activation of an antibiotic-resistance gene encoded by the transposon. These gene-trap clones are transplanted into the testes of recipient males (either as monoclonal or polyclonal libraries); crossing of these founders with wild-type females allows the insertions to be passed to F(1) progeny. This simple, economic and user-friendly methodological pipeline enables screens for functional gene annotation in the rat, with applicability in other vertebrate models where germ line-competent stem cells have been established. The complete protocol from transfection of SSCs to the genotyping of heterozygous F(1) offspring that harbor genomic SB gene-trap insertions takes 5-6 months.
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Ruf S, Symmons O, Uslu VV, Dolle D, Hot C, Ettwiller L, Spitz F. Large-scale analysis of the regulatory architecture of the mouse genome with a transposon-associated sensor. Nat Genet 2011; 43:379-86. [DOI: 10.1038/ng.790] [Citation(s) in RCA: 127] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2010] [Accepted: 02/16/2011] [Indexed: 01/29/2023]
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Grabundzija I, Izsvák Z, Ivics Z. Insertional engineering of chromosomes with Sleeping Beauty transposition: an overview. Methods Mol Biol 2011; 738:69-85. [PMID: 21431720 DOI: 10.1007/978-1-61779-099-7_5] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Novel genetic tools and mutagenesis strategies based on the Sleeping Beauty (SB) transposable element are currently under development with a vision to link primary DNA sequence information to gene functions in vertebrate models. By virtue of its inherent capacity to insert into DNA, the SB transposon can be developed into powerful tools for chromosomal manipulations. Mutagenesis screens based on SB have numerous advantages including high throughput and easy identification of mutated alleles. Forward genetic approaches based on insertional mutagenesis by engineered SB transposons have the advantage of providing insight into genetic networks and pathways based on phenotype. Indeed, the SB transposon has become a highly instrumental tool to induce tumors in experimental animals in a tissue-specific -manner with the aim of uncovering the genetic basis of diverse cancers. Here, we describe a battery of mutagenic cassettes that can be applied in conjunction with SB transposon vectors to mutagenize genes, and highlight versatile experimental strategies for the generation of engineered chromosomes for loss-of-function as well as gain-of-function mutagenesis for functional gene annotation in vertebrate models.
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36
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Ivics Z, Izsvák Z. The expanding universe of transposon technologies for gene and cell engineering. Mob DNA 2010; 1:25. [PMID: 21138556 PMCID: PMC3016246 DOI: 10.1186/1759-8753-1-25] [Citation(s) in RCA: 97] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2010] [Accepted: 12/07/2010] [Indexed: 12/16/2022] Open
Abstract
Transposable elements can be viewed as natural DNA transfer vehicles that, similar to integrating viruses, are capable of efficient genomic insertion. The mobility of class II transposable elements (DNA transposons) can be controlled by conditionally providing the transposase component of the transposition reaction. Thus, a DNA of interest (be it a fluorescent marker, a small hairpin (sh)RNA expression cassette, a mutagenic gene trap or a therapeutic gene construct) cloned between the inverted repeat sequences of a transposon-based vector can be used for stable genomic insertion in a regulated and highly efficient manner. This methodological paradigm opened up a number of avenues for genome manipulations in vertebrates, including transgenesis for the generation of transgenic cells in tissue culture, the production of germline transgenic animals for basic and applied research, forward genetic screens for functional gene annotation in model species, and therapy of genetic disorders in humans. Sleeping Beauty (SB) was the first transposon shown to be capable of gene transfer in vertebrate cells, and recent results confirm that SB supports a full spectrum of genetic engineering including transgenesis, insertional mutagenesis, and therapeutic somatic gene transfer both ex vivo and in vivo. The first clinical application of the SB system will help to validate both the safety and efficacy of this approach. In this review, we describe the major transposon systems currently available (with special emphasis on SB), discuss the various parameters and considerations pertinent to their experimental use, and highlight the state of the art in transposon technology in diverse genetic applications.
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Affiliation(s)
- Zoltán Ivics
- Max Delbrück Center for Molecular Medicine, Berlin, Germany.
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37
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Unique functions of repetitive transcriptomes. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2010; 285:115-88. [PMID: 21035099 DOI: 10.1016/b978-0-12-381047-2.00003-7] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Repetitive sequences occupy a huge fraction of essentially every eukaryotic genome. Repetitive sequences cover more than 50% of mammalian genomic DNAs, whereas gene exons and protein-coding sequences occupy only ~3% and 1%, respectively. Numerous genomic repeats include genes themselves. They generally encode "selfish" proteins necessary for the proliferation of transposable elements (TEs) in the host genome. The major part of evolutionary "older" TEs accumulated mutations over time and fails to encode functional proteins. However, repeats have important functions also on the RNA level. Repetitive transcripts may serve as multifunctional RNAs by participating in the antisense regulation of gene activity and by competing with the host-encoded transcripts for cellular factors. In addition, genomic repeats include regulatory sequences like promoters, enhancers, splice sites, polyadenylation signals, and insulators, which actively reshape cellular transcriptomes. TE expression is tightly controlled by the host cells, and some mechanisms of this regulation were recently decoded. Finally, capacity of TEs to proliferate in the host genome led to the development of multiple biotechnological applications.
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38
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Abstract
Transposable elements are DNA segments with the unique ability to move about in the genome. This inherent feature can be exploited to harness these elements as gene vectors for genome manipulation. Transposon-based genetic strategies have been established in vertebrate species over the last decade, and current progress in this field suggests that transposable elements will serve as indispensable tools. In particular, transposons can be applied as vectors for somatic and germline transgenesis, and as insertional mutagens in both loss-of-function and gain-of-function forward mutagenesis screens. In addition, transposons will gain importance in future cell-based clinical applications, including nonviral gene transfer into stem cells and the rapidly developing field of induced pluripotent stem cells. Here we provide an overview of transposon-based methods used in vertebrate model organisms with an emphasis on the mouse system and highlight the most important considerations concerning genetic applications of the transposon systems.
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39
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Efficient transposition of the Tol2 transposable element from a single-copy donor in zebrafish. Proc Natl Acad Sci U S A 2008; 105:19827-32. [PMID: 19060204 DOI: 10.1073/pnas.0810380105] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The Tol2 transposable element is a powerful genetic tool in model vertebrates and has been used for transgenesis, insertional mutagenesis, gene trapping, and enhancer trapping. However, an in vivo transposition system using Tol2 has not yet been developed. Here we report the in vivo Tol2 transposition system in a model vertebrate, zebrafish. First, we constructed transgenic zebrafish that carried single-copy integrations of Tol2 on the genome and injected transposase mRNA into one-cell stage embryos. The Tol2 insertions were mobilized efficiently in the germ lineage. We then mobilized an insertion of the Tol2 gene trap construct in the nup214 gene, which caused a recessive lethal mutant phenotype, and demonstrated that this method is applicable to the isolation of revertants from a transposon insertional mutant. Second, we constructed transgenic fish carrying the transposase cDNA under the control of the hsp70 promoter. Double-transgenic fish containing the transposase gene and a single-copy Tol2 insertion were treated with heat shock at the adult stage. We found that transposition can be induced efficiently in the male germ cells. We analyzed new integration sites and found that the majority (83%) of them were mapped on chromosomes other than the transposon donor chromosomes and that 9% of local hopping events mapped less than 300 kb away from the donor loci. Our present study demonstrates that the in vivo Tol2 transposition system is useful for creating genome-wide insertions from a single-copy donor and should facilitate functional genomics and transposon biology in vertebrates.
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Finka A, Saidi Y, Goloubinoff P, Neuhaus JM, Zrÿd JP, Schaefer DG. The knock-out of ARP3a gene affects F-actin cytoskeleton organization altering cellular tip growth, morphology and development in moss Physcomitrella patens. ACTA ACUST UNITED AC 2008; 65:769-84. [PMID: 18613119 DOI: 10.1002/cm.20298] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
The seven subunit Arp2/3 complex is a highly conserved nucleation factor of actin microfilaments. We have isolated the genomic sequence encoding a putative Arp3a protein of the moss Physcomitrella patens. The disruption of this ARP3A gene by allele replacement has generated loss-of-function mutants displaying a complex developmental phenotype. The loss-of function of ARP3A gene results in shortened, almost cubic chloronemal cells displaying affected tip growth and lacking differentiation to caulonemal cells. In moss arp3a mutants, buds differentiate directly from chloronemata to form stunted leafy shoots having differentiated leaves similar to wild type. Yet, rhizoids never differentiate from stem epidermal cells. To characterize the F-actin organization in the arp3a-mutated cells, we disrupted ARP3A gene in the previously described HGT1 strain expressing conditionally the GFP-talin marker. In vivo observation of the F-actin cytoskeleton during P. patens development demonstrated that loss-of-function of Arp3a is associated with the disappearance of specific F-actin cortical structures associated with the establishment of localized cellular growth domains. Finally, we show that constitutive expression of the P. patens Arp3a and its Arabidopsis thaliana orthologs efficiently complement the mutated phenotype indicating a high degree of evolutionary conservation of the Arp3 function in land plants.
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Affiliation(s)
- Andrija Finka
- Department of Plant Molecular Biology, University of Lausanne, Lausanne, Switzerland.
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Takeda J, Izsvák Z, Ivics Z. Insertional mutagenesis of the mouse germline with Sleeping Beauty transposition. Methods Mol Biol 2008; 435:109-25. [PMID: 18370071 DOI: 10.1007/978-1-59745-232-8_8] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/10/2023]
Abstract
Efficient linking of primary DNA sequence information to gene functions in vertebrate models requires that genetic modifications and their effects are analyzed in an efficacious, controlled, and scalable manner. Thus, to facilitate analysis of gene function, new genetic tools and strategies are currently under development. Transposable elements, by virtue of their inherent ability to insert into DNA, can be developed into useful tools for chromosomal manipulations. Mutagenesis screens based on transposable elements have numerous advantages as they can be applied in vivo and are therefore phenotype-driven, and molecular analysis of the mutations is straightforward. Current progress in this field indicates that transposable elements will serve as indispensable tools in the genetic toolkit of vertebrate models. Here, we provide experimental protocols for the construction, functional testing, and application of the Sleeping Beauty transposon for insertional mutagenesis of the mouse germline.
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Affiliation(s)
- Junji Takeda
- Center for Advanced Science and Innovation & Department of Social and Environmental Medicine, Osaka University, Osaka, Japan
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42
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Abstract
The actin-related protein 2/3 (Arp2/3) story has captivated the cytoskeleton community for over a decade. Not only does this complex nucleate new actin filaments, but it also anchors them into a dendritic meshwork that is used in many cellular contexts such as lamellipodial protrusion, endosome rocketing, and the movement of pathogens. One key piece of this puzzle that has been missing is a detailed structure of the Arp2/3-actin branch. Using electron tomography and computational docking, Rouiller et al. (Rouiller, I., X.-P. Xu, K.J. Amann, C. Egile, S. Nickell, D. Nicastro, R. Li, T.D. Pollard, N. Volkmann, and D. Hanein. 2008. J. Cell Biol. 180:887–895) present an elegant and intriguing structure of the Arp2/3 complex–mediated actin branch.
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Affiliation(s)
- Liang Cai
- Lineberger Comprehensive Cancer Center, Chapel Hill, NC 27599
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Akiyama K, Morita H, Suetsugu S, Kuraba S, Numata Y, Yamamoto Y, Inui K, Ideura T, Wakisaka N, Nakano K, Oniki H, Takenawa T, Matsuyama M, Yoshimura A. Actin -related protein 3 (Arp3) is mutated in proteinuric BUF/Mna rats. Mamm Genome 2007; 19:41-50. [PMID: 18064521 DOI: 10.1007/s00335-007-9078-5] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2007] [Accepted: 10/23/2007] [Indexed: 11/28/2022]
Abstract
The BUF/Mna strain of rat is a model of focal and segmental glomerulosclerosis (FSGS) in which a quantitative trait locus (QTL) for proteinuria, Pur1, has been identified. The aim of the present study was to identify candidates for the Pur1 gene. To narrow the Pur1 QTL, we performed fine QTL mapping and single nucleotide polymorphism (SNP) genotyping. To identify candidate genes, sequencing and gene-expression analyses of all genes contained in the narrowed locus were conducted. The narrowed Pur1 region contained 25 genes. Among these genes, only the Arp3 gene was mutated in the BUF/Mna strain; it contained a missense mutation that caused an (L)111(F) substitution. This leucine is conserved across species. Gene-expression analysis failed to identify any other candidate genes for Pur1. Arp3-mediated actin assembly abnormalities were visible in immunohistochemical and electron microscopic examinations of podocytes in old BUF/Mna rats. Taken together, these data suggest that Arp3 is a candidate for the Pur1 gene. This observation is consistent with our growing recognition that abnormal signaling-induced assembly of actin in podocytes leads to the development of FSGS.
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Affiliation(s)
- Kiyotaka Akiyama
- Central Pharmaceutical Research Institute, Japan Tobacco Inc, Yokohama, 236-0004, Japan
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