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Antoku S, Schwartz TU, Gundersen GG. FHODs: Nuclear tethered formins for nuclear mechanotransduction. Front Cell Dev Biol 2023; 11:1160219. [PMID: 37215084 PMCID: PMC10192571 DOI: 10.3389/fcell.2023.1160219] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2023] [Accepted: 03/28/2023] [Indexed: 05/24/2023] Open
Abstract
In this review, we discuss FHOD formins with a focus on recent studies that reveal a new role for them as critical links for nuclear mechanotransduction. The FHOD family in vertebrates comprises two structurally related proteins, FHOD1 and FHOD3. Their similar biochemical properties suggest overlapping and redundant functions. FHOD1 is widely expressed, FHOD3 less so, with highest expression in skeletal (FHOD1) and cardiac (FHOD3) muscle where specific splice isoforms are expressed. Unlike other formins, FHODs have strong F-actin bundling activity and relatively weak actin polymerization activity. These activities are regulated by phosphorylation by ROCK and Src kinases; bundling is additionally regulated by ERK1/2 kinases. FHODs are unique among formins in their association with the nuclear envelope through direct, high affinity binding to the outer nuclear membrane proteins nesprin-1G and nesprin-2G. Recent crystallographic structures reveal an interaction between a conserved motif in one of the spectrin repeats (SRs) of nesprin-1G/2G and a site adjacent to the regulatory domain in the amino terminus of FHODs. Nesprins are components of the LINC (linker of nucleoskeleton and cytoskeleton) complex that spans both nuclear membranes and mediates bidirectional transmission of mechanical forces between the nucleus and the cytoskeleton. FHODs interact near the actin-binding calponin homology (CH) domains of nesprin-1G/2G enabling a branched connection to actin filaments that presumably strengthens the interaction. At the cellular level, the tethering of FHODs to the outer nuclear membrane mechanically couples perinuclear actin arrays to the nucleus to move and position it in fibroblasts, cardiomyocytes, and potentially other cells. FHODs also function in adhesion maturation during cell migration and in the generation of sarcomeres, activities distant from the nucleus but that are still influenced by it. Human genetic studies have identified multiple FHOD3 variants linked to dilated and hypertrophic cardiomyopathies, with many mutations mapping to "hot spots" in FHOD3 domains. We discuss how FHOD1/3's role in reinforcing the LINC complex and connecting to perinuclear actin contributes to functions of mechanically active tissues such as striated muscle.
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Affiliation(s)
- Susumu Antoku
- Department of Pathology and Cell Biology, Columbia University, New York, NY, United States
| | - Thomas U. Schwartz
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA, United States
| | - Gregg G. Gundersen
- Department of Pathology and Cell Biology, Columbia University, New York, NY, United States
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2
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Lim SM, Cruz VE, Antoku S, Gundersen GG, Schwartz TU. Structures of FHOD1-Nesprin1/2 complexes reveal alternate binding modes for the FH3 domain of formins. Structure 2021; 29:540-552.e5. [PMID: 33472039 DOI: 10.1016/j.str.2020.12.013] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2020] [Revised: 11/23/2020] [Accepted: 12/21/2020] [Indexed: 12/12/2022]
Abstract
The nuclear position in eukaryotes is controlled by a nucleo-cytoskeletal network, critical in cell differentiation, division, and movement. Forces are transmitted through conserved Linker of Nucleoskeleton and Cytoskeleton (LINC) complexes that traverse the nuclear envelope and engage on either side of the membrane with diverse binding partners. Nesprin-2-giant (Nes2G), a LINC element in the outer nuclear membrane, connects to the actin directly as well as through FHOD1, a formin primarily involved in actin bundling. Here, we report the crystal structure of Nes2G bound to FHOD1 and show that the presumed G-binding domain of FHOD1 is rather a spectrin repeat (SR) binding enhancer for the neighboring FH3 domain. The structure reveals that SR binding by FHOD1 is likely not regulated by the diaphanous-autoregulatory domain helix of FHOD1. Finally, we establish that Nes1G also has one FHOD1 binding SR, indicating that these abundant, giant Nesprins have overlapping functions in actin-bundle recruitment for nuclear movement.
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Affiliation(s)
- Sing Mei Lim
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Victor E Cruz
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Susumu Antoku
- Department of Pathology and Cell Biology, Columbia University, New York, NY 10032, USA
| | - Gregg G Gundersen
- Department of Pathology and Cell Biology, Columbia University, New York, NY 10032, USA
| | - Thomas U Schwartz
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
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Antoku S, Wu W, Joseph LC, Morrow JP, Worman HJ, Gundersen GG. ERK1/2 Phosphorylation of FHOD Connects Signaling and Nuclear Positioning Alternations in Cardiac Laminopathy. Dev Cell 2020; 51:602-616.e12. [PMID: 31794718 DOI: 10.1016/j.devcel.2019.10.023] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2019] [Revised: 08/06/2019] [Accepted: 10/24/2019] [Indexed: 12/13/2022]
Abstract
Mutations in the lamin A/C gene (LMNA) cause cardiomyopathy and also disrupt nuclear positioning in fibroblasts. LMNA mutations causing cardiomyopathy elevate ERK1/2 activity in the heart, and inhibition of the ERK1/2 kinase activity ameliorates pathology, but the downstream effectors remain largely unknown. We now show that cardiomyocytes from mice with an Lmna mutation and elevated cardiac ERK1/2 activity have altered nuclear positioning. In fibroblasts, ERK1/2 activation negatively regulated nuclear movement by phosphorylating S498 of FHOD1. Expression of an unphosphorylatable FHOD1 variant rescued the nuclear movement defect in fibroblasts expressing a cardiomyopathy-causing lamin A mutant. In hearts of mice with LMNA mutation-induced cardiomyopathy, ERK1/2 mediated phosphorylation of FHOD3, an isoform highly expressed in cardiac tissue. Phosphorylation of FHOD1 and FHOD3 inhibited their actin bundling activity. These results show that phosphorylation of FHOD proteins by ERK1/2 is a critical switch for nuclear positioning and may play a role in the pathogenesis of cardiomyopathy caused by LMNA mutations.
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Affiliation(s)
- Susumu Antoku
- Department of Pathology and Cell Biology, Vagelos College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA
| | - Wei Wu
- Department of Pathology and Cell Biology, Vagelos College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA; Department of Medicine, Vagelos College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA
| | - Leroy C Joseph
- Department of Medicine, Vagelos College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA
| | - John P Morrow
- Department of Medicine, Vagelos College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA
| | - Howard J Worman
- Department of Pathology and Cell Biology, Vagelos College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA; Department of Medicine, Vagelos College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA
| | - Gregg G Gundersen
- Department of Pathology and Cell Biology, Vagelos College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA.
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Zhang Q, Narayanan V, Mui KL, O'Bryan CS, Anderson RH, Kc B, Cabe JI, Denis KB, Antoku S, Roux KJ, Dickinson RB, Angelini TE, Gundersen GG, Conway DE, Lele TP. Mechanical Stabilization of the Glandular Acinus by Linker of Nucleoskeleton and Cytoskeleton Complex. Curr Biol 2019; 29:2826-2839.e4. [PMID: 31402305 PMCID: PMC6736724 DOI: 10.1016/j.cub.2019.07.021] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2019] [Revised: 06/03/2019] [Accepted: 07/09/2019] [Indexed: 12/19/2022]
Abstract
The nucleoskeleton and cytoskeleton are important protein networks that govern cellular behavior and are connected together by the linker of nucleoskeleton and cytoskeleton (LINC) complex. Mutations in LINC complex components may be relevant to cancer, but how cell-level changes might translate into tissue-level malignancy is unclear. We used glandular epithelial cells in a three-dimensional culture model to investigate the effect of perturbations of the LINC complex on higher order cellular architecture. We show that inducible LINC complex disruption in human mammary epithelial MCF-10A cells and canine kidney epithelial MDCK II cells mechanically destabilizes the acinus. Lumenal collapse occurs because the acinus is unstable to increased mechanical tension that is caused by upregulation of Rho-kinase-dependent non-muscle myosin II motor activity. These findings provide a potential mechanistic explanation for how disruption of LINC complex may contribute to a loss of tissue structure in glandular epithelia.
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Affiliation(s)
- Qiao Zhang
- Department of Chemical Engineering, University of Florida, Gainesville, FL 32611, USA
| | - Vani Narayanan
- Department of Biomedical Engineering, Virginia Commonwealth University, Richmond, VA 23284, USA
| | - Keeley L Mui
- Department of Pathology and Cell Biology, Vagelos College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA
| | - Christopher S O'Bryan
- Department of Mechanical and Aerospace Engineering, University of Florida, Gainesville, FL 32611, USA
| | | | - Birendra Kc
- Enabling Technologies Group, Sanford Research, Sioux Falls, SD 57104, USA
| | - Jolene I Cabe
- Department of Biomedical Engineering, Virginia Commonwealth University, Richmond, VA 23284, USA
| | - Kevin B Denis
- Department of Biomedical Engineering, Virginia Commonwealth University, Richmond, VA 23284, USA
| | - Susumu Antoku
- Department of Pathology and Cell Biology, Vagelos College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA
| | - Kyle J Roux
- Enabling Technologies Group, Sanford Research, Sioux Falls, SD 57104, USA; Department of Pediatrics, Sanford School of Medicine, University of South Dakota, Sioux Falls, SD 57105, USA
| | - Richard B Dickinson
- Department of Chemical Engineering, University of Florida, Gainesville, FL 32611, USA
| | - Thomas E Angelini
- Department of Mechanical and Aerospace Engineering, University of Florida, Gainesville, FL 32611, USA
| | - Gregg G Gundersen
- Department of Pathology and Cell Biology, Vagelos College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA
| | - Daniel E Conway
- Department of Biomedical Engineering, Virginia Commonwealth University, Richmond, VA 23284, USA.
| | - Tanmay P Lele
- Department of Chemical Engineering, University of Florida, Gainesville, FL 32611, USA.
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Roh-Johnson M, Shah AN, Stonick JA, Poudel KR, Kargl J, Yang GH, di Martino J, Hernandez RE, Gast CE, Zarour LR, Antoku S, Houghton AM, Bravo-Cordero JJ, Wong MH, Condeelis J, Moens CB. Macrophage-Dependent Cytoplasmic Transfer during Melanoma Invasion In Vivo. Dev Cell 2018; 43:549-562.e6. [PMID: 29207258 DOI: 10.1016/j.devcel.2017.11.003] [Citation(s) in RCA: 79] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2017] [Revised: 09/15/2017] [Accepted: 11/04/2017] [Indexed: 12/31/2022]
Abstract
Interactions between tumor cells and tumor-associated macrophages play critical roles in the initiation of tumor cell motility. To capture the cellular interactions of the tumor microenvironment with high-resolution imaging, we directly visualized tumor cells and their interactions with macrophages in zebrafish. Live imaging in zebrafish revealed that macrophages are dynamic, yet maintain sustained contact with tumor cells. In addition, the recruitment of macrophages to tumor cells promotes tumor cell dissemination. Using a Cre/LoxP strategy, we found that macrophages transfer cytoplasm to tumor cells in zebrafish and mouse models. Remarkably, macrophage cytoplasmic transfer correlated with melanoma cell dissemination. We further found that macrophages transfer cytoplasm to tumor cells upon cell contact in vitro. Thus, we present a model in which macrophage/tumor cell contact allows for the transfer of cytoplasmic molecules from macrophages to tumor cells corresponding to increased tumor cell motility and dissemination.
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Affiliation(s)
- Minna Roh-Johnson
- Fred Hutchinson Cancer Research Center, Basic Sciences Division, Seattle, WA 98109, USA.
| | - Arish N Shah
- Fred Hutchinson Cancer Research Center, Basic Sciences Division, Seattle, WA 98109, USA
| | - Jason A Stonick
- Fred Hutchinson Cancer Research Center, Basic Sciences Division, Seattle, WA 98109, USA
| | - Kumud R Poudel
- Fred Hutchinson Cancer Research Center, Basic Sciences Division, Seattle, WA 98109, USA
| | - Julia Kargl
- Fred Hutchinson Cancer Research Center, Clinical Research Division, Seattle, WA 98109, USA; Institute of Experimental and Clinical Pharmacology, Medical University of Graz, Graz 8036, Austria
| | - Grace H Yang
- Fred Hutchinson Cancer Research Center, Clinical Research Division, Seattle, WA 98109, USA
| | - Julie di Martino
- Icahn School of Medicine at Mount Sinai, Division of Hematology and Oncology, Department of Medicine, New York, NY 10029, USA
| | | | - Charles E Gast
- Oregon Health & Science University, Department of Cell, Developmental, and Cancer Biology, The Knight Cancer Institute, Portland, OR 97239, USA
| | - Luai R Zarour
- Oregon Health & Science University, Department of Surgery, Portland, OR 97239, USA
| | - Susumu Antoku
- Columbia University, Department of Pathology and Cell Biology, New York, NY 10027, USA
| | - A McGarry Houghton
- Fred Hutchinson Cancer Research Center, Clinical Research Division, Seattle, WA 98109, USA
| | - Jose Javier Bravo-Cordero
- Icahn School of Medicine at Mount Sinai, Division of Hematology and Oncology, Department of Medicine, New York, NY 10029, USA
| | - Melissa H Wong
- Oregon Health & Science University, Department of Cell, Developmental, and Cancer Biology, The Knight Cancer Institute, Portland, OR 97239, USA
| | - John Condeelis
- Albert Einstein College of Medicine, Department of Anatomy and Structural Biology, Bronx, NY 10461, USA
| | - Cecilia B Moens
- Fred Hutchinson Cancer Research Center, Basic Sciences Division, Seattle, WA 98109, USA
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Abstract
Nuclei are connected to the actin cytoskeleton for controlling its position in the cell and for mechanochemical signaling. Nesprin-2G is one of the major outer nuclear membrane proteins that links the nucleus to the actin cytoskeleton. In addition to its paired calponin homology (CH) domains, nesprin-2G interacts with actin filaments by binding the actin-bundling proteins FHOD1 and fascin. We describe methods to measure the interaction of nesprin-2G with actin filaments using an actin co-sedimentation assay and with its binding partner FHOD1 using a GST pull-down method.
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Affiliation(s)
- Susumu Antoku
- Department of Pathology and Cell Biology, Columbia University, New York, NY, USA
| | - Gregg G Gundersen
- Department of Pathology and Cell Biology, Columbia University, New York, NY, USA.
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Zhu R, Antoku S, Gundersen GG. Centrifugal Displacement of Nuclei Reveals Multiple LINC Complex Mechanisms for Homeostatic Nuclear Positioning. Curr Biol 2017; 27:3097-3110.e5. [PMID: 28988861 DOI: 10.1016/j.cub.2017.08.073] [Citation(s) in RCA: 55] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2017] [Revised: 07/26/2017] [Accepted: 08/30/2017] [Indexed: 11/18/2022]
Abstract
Nuclear movement is critical for developmental events, cell polarity, and migration and is usually mediated by linker of nucleoskeleton and cytoskeleton (LINC) complexes connecting the nucleus to cytoskeletal elements. Compared to active nuclear movement, relatively little is known about homeostatic positioning of nuclei, including whether it is an active process. To explore homeostatic nuclear positioning, we developed a method to displace nuclei in adherent cells using centrifugal force. Nuclei displaced by centrifugation rapidly recentered by mechanisms that depended on cell context. In cell monolayers with wounds oriented orthogonal to the force, nuclei were displaced toward the front and back of the cells on the two sides of the wound. Nuclei recentered from both positions, but at different rates and with different cytoskeletal linkage mechanisms. Rearward recentering was actomyosin, nesprin-2G, and SUN2 dependent, whereas forward recentering was microtubule, dynein, nesprin-2G, and SUN1 dependent. Nesprin-2G engaged actin through its N terminus and microtubules through a novel dynein interacting site near its C terminus. Both activities were necessary to maintain nuclear position in uncentrifuged cells. Thus, even when not moving, nuclei are actively maintained in position by engaging the cytoskeleton through the LINC complex.
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Affiliation(s)
- Ruijun Zhu
- Department of Pathology and Cell Biology, Columbia University, 630 West 168(th) Street, New York, NY 10032, USA
| | - Susumu Antoku
- Department of Pathology and Cell Biology, Columbia University, 630 West 168(th) Street, New York, NY 10032, USA
| | - Gregg G Gundersen
- Department of Pathology and Cell Biology, Columbia University, 630 West 168(th) Street, New York, NY 10032, USA.
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Jayo A, Malboubi M, Antoku S, Chang W, Ortiz-Zapater E, Groen C, Pfisterer K, Tootle T, Charras G, Gundersen GG, Parsons M. Fascin Regulates Nuclear Movement and Deformation in Migrating Cells. Dev Cell 2017; 38:371-83. [PMID: 27554857 PMCID: PMC4997957 DOI: 10.1016/j.devcel.2016.07.021] [Citation(s) in RCA: 97] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2016] [Revised: 05/25/2016] [Accepted: 07/25/2016] [Indexed: 12/16/2022]
Abstract
Fascin is an F-actin-bundling protein shown to stabilize filopodia and regulate adhesion dynamics in migrating cells, and its expression is correlated with poor prognosis and increased metastatic potential in a number of cancers. Here, we identified the nuclear envelope protein nesprin-2 as a binding partner for fascin in a range of cell types in vitro and in vivo. Nesprin-2 interacts with fascin through a direct, F-actin-independent interaction, and this binding is distinct and separable from a role for fascin within filopodia at the cell periphery. Moreover, disrupting the interaction between fascin and nesprin-2 C-terminal domain leads to specific defects in F-actin coupling to the nuclear envelope, nuclear movement, and the ability of cells to deform their nucleus to invade through confined spaces. Together, our results uncover a role for fascin that operates independently of filopodia assembly to promote efficient cell migration and invasion. Fascin binds directly to nesprin-2 at the nuclear envelope Fascin-nesprin-2 binding occurs independently of fascin-actin bundling The fascin-nesprin-2 complex regulates nuclear movement in migration Uncoupling the fascin-nesprin complex reduces nuclear deformation and cell invasion
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Affiliation(s)
- Asier Jayo
- Randall Division of Cell and Molecular Biophysics, King's College London, New Hunt's House, Guys Campus, London SE1 1UL, UK
| | - Majid Malboubi
- London Centre for Nanotechnology, University College London, London WC1H 0AH, UK
| | - Susumu Antoku
- Department of Pathology and Cell Biology, Columbia University, New York, NY 10032, USA
| | - Wakam Chang
- Department of Pathology and Cell Biology, Columbia University, New York, NY 10032, USA
| | - Elena Ortiz-Zapater
- Division of Asthma, Allergy & Lung Biology, King's College London, 5th Floor Tower Wing, Guy's Hospital Campus, London SE1 1UL, UK
| | - Christopher Groen
- Anatomy and Cell Biology, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
| | - Karin Pfisterer
- Randall Division of Cell and Molecular Biophysics, King's College London, New Hunt's House, Guys Campus, London SE1 1UL, UK
| | - Tina Tootle
- Anatomy and Cell Biology, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
| | - Guillaume Charras
- London Centre for Nanotechnology, University College London, London WC1H 0AH, UK; Department of Cell and Developmental Biology, University College London, London WC1E 6BT, UK
| | - Gregg G Gundersen
- Department of Pathology and Cell Biology, Columbia University, New York, NY 10032, USA
| | - Maddy Parsons
- Randall Division of Cell and Molecular Biophysics, King's College London, New Hunt's House, Guys Campus, London SE1 1UL, UK.
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Abstract
The rearward positioning of the nucleus is a characteristic feature of most migrating cells. Studies using wounded monolayers of fibroblasts and myoblasts have shown that this positioning is actively established before migration by the coupling of dorsal actin cables to the nuclear envelope through nesprin-2G and SUN2 linker of nucleoskeleton and cytoskeleton (LINC) complexes. During nuclear movement, these LINC complexes cluster along the actin cables to form adhesive structures known as transmembrane actin-associated nuclear (TAN) lines. Here we described experimental procedures for studying nuclear movement and TAN lines using wounded monolayers of fibroblasts and myoblasts, the acquisition of data using immunofluorescence microscopy and live-cell imaging, and methods for data analysis and quantification.
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Affiliation(s)
- Wakam Chang
- Department of Pathology and Cell Biology, College of Physicians and Surgeons, Columbia University, P&S 15-420, 630 West 168th Street, New York, NY, 10032, USA
| | - Susumu Antoku
- Department of Pathology and Cell Biology, College of Physicians and Surgeons, Columbia University, P&S 15-420, 630 West 168th Street, New York, NY, 10032, USA
| | - Gregg G Gundersen
- Department of Pathology and Cell Biology, College of Physicians and Surgeons, Columbia University, P&S 15-420, 630 West 168th Street, New York, NY, 10032, USA.
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Chang W, Antoku S, Östlund C, Worman HJ, Gundersen GG. Linker of nucleoskeleton and cytoskeleton (LINC) complex-mediated actin-dependent nuclear positioning orients centrosomes in migrating myoblasts. Nucleus 2015; 6:77-88. [PMID: 25587885 DOI: 10.1080/19491034.2015.1004947] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022] Open
Abstract
Myoblast migration is essential for muscle development and repair; however, the factors that contribute to the polarity of migrating myoblasts are relatively unknown. We find that randomly migrating C2C12 myoblasts orient their centrosomes in the direction of migration. Using wounded monolayers, we further show that centrosome orientation is stimulated by the serum factor lysophosphatidic acid (LPA) and involves the rearward movement of the nucleus while the centrosome is maintained at the cell centroid. The rate of nuclear movement correlated with that of actin retrograde flow and both cytochalasin D and blebbistatin prevented nuclear movement and centrosome orientation. Actin-dependent rearward nuclear movement in fibroblasts is mediated by assembly of nuclear membrane nesprin-2G and SUN2 LINC complexes into transmembrane actin-associated nuclear (TAN) lines anchored by A-type lamins and emerin. In C2C12 myoblasts, depletion of nesprin-2G, SUN2 or lamin A/C prevented nuclear movement and endogenous nesprin-2G and a chimeric GFP-mini-nesprin-2G formed TAN lines during nuclear movement. Depleting nesprin-2G strongly interfered with directed cell migration and reduced the efficiency of myoblast fusion into multinucleated myotubes. Our results show that nuclear movement contributes to centrosome orientation and polarity for efficient migration and fusion of myoblasts. Given that mutations in the genes encoding A-type lamins, nesprin-2 and SUN2 cause Emery-Dreifuss muscular dystrophy and related myopathies, our results have implications for understanding the mechanism of disease pathogenesis.
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Affiliation(s)
- Wakam Chang
- a Department of Pathology and Cell Biology ; College of Physicians and Surgeons; Columbia University ; New York , NY USA
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Antoku S, Zhu R, Kutscheidt S, Fackler OT, Gundersen GG. Reinforcing the LINC complex connection to actin filaments: the role of FHOD1 in TAN line formation and nuclear movement. Cell Cycle 2015; 14:2200-5. [PMID: 26083340 DOI: 10.1080/15384101.2015.1053665] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022] Open
Abstract
Positioning the nucleus is critical for many cellular processes including cell division, migration and differentiation. The linker of nucleoskeleton and cytoskeleton (LINC) complex spans the inner and outer nuclear membranes and has emerged as a major factor in connecting the nucleus to the cytoskeleton for movement and positioning. Recently, we discovered that the diaphanous formin family member FHOD1 interacts with the LINC complex component nesprin-2 giant (nesprin-2G) and that this interaction plays essential roles in the formation of transmembrane actin-dependent nuclear (TAN) lines and nuclear movement during cell polarization in fibroblasts. We found that FHOD1 strengthens the connection between nesprin-2G and rearward moving dorsal actin cables by providing a second site of interaction between nesprin-2G and the actin cable. These results indicate that the LINC complex connection to the actin cytoskeleton can be enhanced by cytoplasmic factors and suggest a new model for TAN line formation. We discuss how the nesprin-2G-FHOD1 interaction may be regulated and its possible functional significance for development and disease.
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Key Words
- ABS, actin binding site
- ANC-1, Syne homology
- CH, calponin homology
- DAD, diaphanous autoregulatory domain
- DID, diaphanous inhibitory domain
- DRF, diaphanous related formin
- EDMD, Emery-Dreifuss muscular dystrophy
- Emery-Dreifuss muscular dystrophy
- FH, formin homology
- FHOD1
- GBD, GTPase binding domain
- GFP-mN2G, GFP-mini-nesprin-2G
- KASH, Klarsicht
- LINC Complex
- LINC, linker of nucleoskeleton and cytoskeleton
- LPA, lysophosphatidic acid
- SR, spectrin repeat
- TAN lines
- TAN lines, transmembrane actin-dependent nuclear lines
- actin filaments
- formin
- nesprin
- nesprin-2G, nesprin-2 giant
- nuclear movement
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Affiliation(s)
- Susumu Antoku
- a Department of Pathology & Cell Biology ; Columbia University ; New York , NY USA
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Meinke P, Mattioli E, Haque F, Antoku S, Columbaro M, Straatman KR, Worman HJ, Gundersen GG, Lattanzi G, Wehnert M, Shackleton S. Muscular dystrophy-associated SUN1 and SUN2 variants disrupt nuclear-cytoskeletal connections and myonuclear organization. PLoS Genet 2014; 10:e1004605. [PMID: 25210889 PMCID: PMC4161305 DOI: 10.1371/journal.pgen.1004605] [Citation(s) in RCA: 125] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2013] [Accepted: 07/16/2014] [Indexed: 11/19/2022] Open
Abstract
Proteins of the nuclear envelope (NE) are associated with a range of inherited disorders, most commonly involving muscular dystrophy and cardiomyopathy, as exemplified by Emery-Dreifuss muscular dystrophy (EDMD). EDMD is both genetically and phenotypically variable, and some evidence of modifier genes has been reported. Six genes have so far been linked to EDMD, four encoding proteins associated with the LINC complex that connects the nucleus to the cytoskeleton. However, 50% of patients have no identifiable mutations in these genes. Using a candidate approach, we have identified putative disease-causing variants in the SUN1 and SUN2 genes, also encoding LINC complex components, in patients with EDMD and related myopathies. Our data also suggest that SUN1 and SUN2 can act as disease modifier genes in individuals with co-segregating mutations in other EDMD genes. Five SUN1/SUN2 variants examined impaired rearward nuclear repositioning in fibroblasts, confirming defective LINC complex function in nuclear-cytoskeletal coupling. Furthermore, myotubes from a patient carrying compound heterozygous SUN1 mutations displayed gross defects in myonuclear organization. This was accompanied by loss of recruitment of centrosomal marker, pericentrin, to the NE and impaired microtubule nucleation at the NE, events that are required for correct myonuclear arrangement. These defects were recapitulated in C2C12 myotubes expressing exogenous SUN1 variants, demonstrating a direct link between SUN1 mutation and impairment of nuclear-microtubule coupling and myonuclear positioning. Our findings strongly support an important role for SUN1 and SUN2 in muscle disease pathogenesis and support the hypothesis that defects in the LINC complex contribute to disease pathology through disruption of nuclear-microtubule association, resulting in defective myonuclear positioning. Emery-Dreifuss muscular dystrophy (EDMD) is an inherited disorder involving muscle wasting and weakness, accompanied by cardiac defects. The disease is variable in its severity and also in its genetic cause. So far, 6 genes have been linked to EDMD, most encoding proteins that form a structural network that supports the nucleus of the cell and connects it to structural elements of the cytoplasm. This network is particularly important in muscle cells, providing resistance to mechanical strain. Weakening of this network is thought to contribute to development of muscle disease in these patients. Despite rigorous screening, at least 50% of patients with EDMD have no detectable mutation in the 6 known genes. We therefore undertook screening and identified mutations in two additional genes that encode other components of the nuclear structural network, SUN1 and SUN2. Our findings add to the genetic complexity of this disease since some individuals carry mutations in more than one gene. We also show that the mutations disrupt connections between the nucleus and the structural elements of cytoplasm, leading to mis-positioning and clustering of nuclei in muscle cells. This nuclear mis-positioning is likely to be another factor contributing to pathogenesis of EDMD.
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Affiliation(s)
- Peter Meinke
- Institute of Human Genetics and Interfaculty Institute of Genetics and Functional Genomics, University of Greifswald, Greifswald, Germany
| | - Elisabetta Mattioli
- National Research Council of Italy - CNR - Institute for Molecular Genetics, Unit of Bologna IOR, Bologna, Italy
- Rizzoli Orthopaedic Institute, Laboratory of Musculoskeletal Cell Biology, Bologna, Italy
| | - Farhana Haque
- Department of Biochemistry, University of Leicester, Leicester, United Kingdom
| | - Susumu Antoku
- Department of Pathology and Cell Biology, College of Physicians and Surgeons, Columbia University, New York, New York, United States of America
| | - Marta Columbaro
- Rizzoli Orthopaedic Institute, Laboratory of Musculoskeletal Cell Biology, Bologna, Italy
| | - Kees R. Straatman
- Centre for Core Biotechnology Services, University of Leicester, Leicester, United Kingdom
| | - Howard J. Worman
- Department of Pathology and Cell Biology, College of Physicians and Surgeons, Columbia University, New York, New York, United States of America
- Department of Medicine, College of Physicians and Surgeons, Columbia University, New York, New York, United States of America
| | - Gregg G. Gundersen
- Department of Pathology and Cell Biology, College of Physicians and Surgeons, Columbia University, New York, New York, United States of America
| | - Giovanna Lattanzi
- National Research Council of Italy - CNR - Institute for Molecular Genetics, Unit of Bologna IOR, Bologna, Italy
- Rizzoli Orthopaedic Institute, Laboratory of Musculoskeletal Cell Biology, Bologna, Italy
| | - Manfred Wehnert
- Institute of Human Genetics and Interfaculty Institute of Genetics and Functional Genomics, University of Greifswald, Greifswald, Germany
| | - Sue Shackleton
- Department of Biochemistry, University of Leicester, Leicester, United Kingdom
- * E-mail:
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13
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Kutscheidt S, Zhu R, Antoku S, Luxton GWG, Stagljar I, Fackler OT, Gundersen GG. FHOD1 interaction with nesprin-2G mediates TAN line formation and nuclear movement. Nat Cell Biol 2014; 16:708-15. [PMID: 24880667 PMCID: PMC4113092 DOI: 10.1038/ncb2981] [Citation(s) in RCA: 86] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2013] [Accepted: 04/30/2014] [Indexed: 12/26/2022]
Abstract
Active positioning of the nucleus is integral to division, migration, and differentiation of mammalian cells1. Fibroblasts polarizing for migration orient their centrosomes by actin-dependent nuclear movement2. This nuclear movement depends on nesprin-2 giant (N2G), a large, actin-binding outer nuclear membrane component of transmembrane actin-associated (TAN) lines that couple nuclei to moving actin cables3. Here, we identify the diaphanous formin FHOD1 as an interaction partner of N2G. Silencing FHOD1 expression or expression of fragments containing binding sites of N2G or FHOD1 disrupted nuclear movement and centrosome orientation in polarizing fibroblasts. Unexpectedly, silencing of FHOD1 expression did not affect the formation or rearward flow of dorsal actin cables required for nuclear positioning. Rather, N2G-FHOD1 interaction provided a second connection to actin cables essential for TAN line formation and thus nuclear movement. These results reveal a unique function for a formin in coupling an organelle to actin filaments for translocation and suggest that TAN lines require multi-point attachments to actin cables to resist the large forces necessary to move the nucleus.
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Affiliation(s)
- Stefan Kutscheidt
- 1] Department of Infectious Diseases, Integrative Virology, University Hospital Heidelberg, Heidelberg, INF 324, 69120 Heidelberg, Germany [2]
| | - Ruijun Zhu
- 1] Department of Pathology and Cell Biology, Columbia University, New York, New York 10032, USA [2]
| | - Susumu Antoku
- 1] Department of Pathology and Cell Biology, Columbia University, New York, New York 10032, USA [2]
| | - G W Gant Luxton
- 1] Department of Pathology and Cell Biology, Columbia University, New York, New York 10032, USA [2]
| | - Igor Stagljar
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario M5S 3E1, Canada
| | - Oliver T Fackler
- Department of Infectious Diseases, Integrative Virology, University Hospital Heidelberg, Heidelberg, INF 324, 69120 Heidelberg, Germany
| | - Gregg G Gundersen
- Department of Pathology and Cell Biology, Columbia University, New York, New York 10032, USA
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14
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Sinnar SA, Antoku S, Saffin JM, Cooper JA, Halpain S. Capping protein is essential for cell migration in vivo and for filopodial morphology and dynamics. Mol Biol Cell 2014; 25:2152-60. [PMID: 24829386 PMCID: PMC4091828 DOI: 10.1091/mbc.e13-12-0749] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
This study shows that capping protein (CP) is essential for mammalian cell migration in vitro and in vivo. The authors also show that CP is present in filopodia of multiple cell types and that it regulates filopodial structure and function. Thus CP function in both lamellipodia and filopodia may contribute to efficient migration. Capping protein (CP) binds to barbed ends of growing actin filaments and inhibits elongation. CP is essential for actin-based motility in cell-free systems and in Dictyostelium. Even though CP is believed to be critical for creating the lamellipodial actin structure necessary for protrusion and migration, CP's role in mammalian cell migration has not been directly tested. Moreover, recent studies have suggested that structures besides lamellipodia, including lamella and filopodia, may have unappreciated roles in cell migration. CP has been postulated to be absent from filopodia, and thus its role in filopodial activity has remained unexplored. We report that silencing CP in both cultured mammalian B16F10 cells and in neurons of developing neocortex impaired cell migration. Moreover, we unexpectedly observed that low levels of CP were detectable in the majority of filopodia. CP depletion decreased filopodial length, altered filopodial shape, and reduced filopodial dynamics. Our results support an expansion of the potential roles that CP plays in cell motility by implicating CP in filopodia as well as in lamellipodia, both of which are important for locomotion in many types of migrating cells.
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Affiliation(s)
- Shamim A Sinnar
- Division of Biological Sciences, University of California, San Diego, and Sanford Consortium for Regenerative Medicine, La Jolla, CA 92037
| | - Susumu Antoku
- Fred Hutchinson Cancer Research Center, Seattle, WA 98109
| | - Jean-Michel Saffin
- Division of Biological Sciences, University of California, San Diego, and Sanford Consortium for Regenerative Medicine, La Jolla, CA 92037
| | - Jon A Cooper
- Fred Hutchinson Cancer Research Center, Seattle, WA 98109
| | - Shelley Halpain
- Division of Biological Sciences, University of California, San Diego, and Sanford Consortium for Regenerative Medicine, La Jolla, CA 92037
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15
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Ito H, Takeuchi Y, Ishida H, Antoku S, Abe M, Mifune M, Togane M. High frequencies of diabetic micro- and macroangiopathies in patients with type 2 diabetes mellitus with decreased estimated glomerular filtration rate and normoalbuminuria. Nephrol Dial Transplant 2009; 25:1161-7. [DOI: 10.1093/ndt/gfp579] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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16
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Abstract
Crk family adaptors, consisting of Src homology 2 (SH2) and SH3 protein-binding domains, mediate assembly of protein complexes in signaling. CrkI, an alternately spliced form of Crk, lacks the regulatory phosphorylation site and C-terminal SH3 domain present in CrkII and CrkL. We used gene silencing combined with mutational analysis to probe the role of Crk adaptors in platelet-derived growth-factor receptor beta (PDGFbetaR) signaling. We demonstrate that Crk adaptors are required for formation of focal adhesions, and for PDGF-stimulated remodeling of the actin cytoskeleton and cell migration. Crk-dependent signaling is crucial during the early stages of PDGFbetaR activation, whereas its termination by Abl family tyrosine kinases is important for turnover of focal adhesions and progression of dorsal-membrane ruffles. CrkII and CrkL preferentially activate the small GTPase Rac1, whereas variants lacking a functional C-terminal SH3 domain, including CrkI, preferentially activate Rap1. Thus, differences in the activity of Crk isoforms, including their effectors and their ability to be downregulated by phosphorylation, are important for coordinating dynamic changes in the actin cytoskeleton in response to extracellular signals.
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Affiliation(s)
- Susumu Antoku
- Department of Genetics and Developmental Biology, University of Connecticut Health Center, Farmington, CT 06030-3301, USA
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17
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Antoku S, Saksela K, Rivera GM, Mayer BJ. A crucial role in cell spreading for the interaction of Abl PxxP motifs with Crk and Nck adaptors. J Cell Sci 2008; 121:3071-82. [PMID: 18768933 DOI: 10.1242/jcs.031575] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
The dynamic reorganization of actin structures helps to mediate the interaction of cells with their environment. The Abl non-receptor tyrosine kinase can modulate actin rearrangement during cell attachment. Here we report that the Abl PxxP motifs, which bind Src homology 3 (SH3) domains, are indispensable for the coordinated regulation of filopodium and focal adhesion formation and cell-spreading dynamics during attachment. Candidate Abl PxxP-motif-binding partners were identified by screening a comprehensive SH3-domain phage-display library. A combination of protein overexpression, silencing, pharmacological manipulation and mutational analysis demonstrated that the PxxP motifs of Abl exert their effects on actin organization by two distinct mechanisms, involving the inhibition of Crk signaling and the engagement of Nck. These results uncover a previously unappreciated role for Abl PxxP motifs in the regulation of cell spreading.
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Affiliation(s)
- Susumu Antoku
- Department of Genetics and Developmental Biology, University of Connecticut Health Center, Farmington, CT 06030-3301 USA
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18
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Rivera GM, Antoku S, Gelkop S, Shin NY, Hanks SK, Pawson T, Mayer BJ. Requirement of Nck adaptors for actin dynamics and cell migration stimulated by platelet-derived growth factor B. Proc Natl Acad Sci U S A 2006; 103:9536-41. [PMID: 16769879 PMCID: PMC1476694 DOI: 10.1073/pnas.0603786103] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
The Nck family of Src homology (SH) 2/SH3 domain adaptors functions to link tyrosine phosphorylation induced by extracellular signals with downstream regulators of actin dynamics. We investigated the role of mammalian Nck adaptors in signaling from the activated platelet-derived growth factor (PDGF) receptor (PDGFbetaR) to the actin cytoskeleton. We report here that Nck adaptors are required for cytoskeletal reorganization and chemotaxis stimulated by PDGF-B. Analysis of tyrosine-phosphorylated proteins demonstrated that Crk-associated substrate (p130(Cas)), not the activated PDGFbetaR itself, is the major Nck SH2 domain-binding protein in PDGF-B-stimulated cells. Both Nck- and p130(Cas)-deficient cells fail to display cytoskeletal rearrangements, including the formation of membrane ruffles and the disassembly of actin bundles, typically shown by their WT counterparts in response to PDGF-B. Furthermore, Nck and p130(Cas) colocalize in phosphotyrosine-enriched membrane ruffles induced by PDGF-B in NIH 3T3 cells. These results suggest that Nck adaptors play an essential role in linking the activated PDGFbetaR with actin dynamics through a pathway that involves p130(Cas).
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Affiliation(s)
- G. M. Rivera
- *Raymond and Beverly Sackler Laboratory of Genetics and Molecular Medicine, Department of Genetics and Developmental Biology and Center for Cell Analysis and Modeling, University of Connecticut Health Center, Farmington, CT 06030
| | - S. Antoku
- *Raymond and Beverly Sackler Laboratory of Genetics and Molecular Medicine, Department of Genetics and Developmental Biology and Center for Cell Analysis and Modeling, University of Connecticut Health Center, Farmington, CT 06030
| | - S. Gelkop
- Samuel Lunenfeld Research Institute, Mount Sinai Hospital, Toronto, ON, Canada M5G 1X5; and
| | - N. Y. Shin
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37232
| | - S. K. Hanks
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37232
| | - T. Pawson
- Samuel Lunenfeld Research Institute, Mount Sinai Hospital, Toronto, ON, Canada M5G 1X5; and
- To whom correspondence may be addressed. E-mail:
or
| | - B. J. Mayer
- *Raymond and Beverly Sackler Laboratory of Genetics and Molecular Medicine, Department of Genetics and Developmental Biology and Center for Cell Analysis and Modeling, University of Connecticut Health Center, Farmington, CT 06030
- To whom correspondence may be addressed. E-mail:
or
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19
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Reuven NB, Antoku S, Weller SK. The UL12.5 gene product of herpes simplex virus type 1 exhibits nuclease and strand exchange activities but does not localize to the nucleus. J Virol 2004; 78:4599-608. [PMID: 15078942 PMCID: PMC387724 DOI: 10.1128/jvi.78.9.4599-4608.2004] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The herpes simplex virus type 1 (HSV-1) alkaline nuclease, encoded by the UL12 gene, plays an important role in HSV-1 replication, as a null mutant of UL12 displays a severe growth defect. Although the precise in vivo role of UL12 has not yet been determined, several in vitro activities have been identified for the protein, including endo- and exonuclease activities, interaction with the HSV-1 single-stranded DNA binding protein ICP8, and an ability to promote strand exchange in conjunction with ICP8. In this study, we examined a naturally occurring N-terminally truncated version of UL12 called UL12.5. Previous studies showing that UL12.5 exhibits nuclease activity but is unable to complement a UL12 null virus posed a dilemma and suggested that UL12.5 may lack a critical activity possessed by the full-length protein, UL12. We constructed a recombinant baculovirus capable of expressing UL12.5 and purified soluble UL12.5 from infected insect cells. The purified UL12.5 exhibited both endo- and exonuclease activities but was less active than UL12. Like UL12, UL12.5 could mediate strand exchange with ICP8 and could also be coimmunoprecipitated with ICP8. The primary difference between the two proteins was in their intracellular localization, with UL12 localizing to the nucleus and UL12.5 remaining in the cytoplasm. We mapped a nuclear localization signal to the N terminus of UL12, the domain absent from UL12.5. In addition, when UL12.5 was overexpressed so that some of the enzyme leaked into the nucleus, it was able to partially complement the UL12 null mutant.
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Affiliation(s)
- Nina Bacher Reuven
- Department of Molecular, Microbial, and Structural Biology, University of Connecticut Health Center, Farmington, Connecticut 06030-3205, USA
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20
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Sharma A, Antoku S, Fujiwara K, Mayer BJ. Functional interaction trap: a strategy for validating the functional consequences of tyrosine phosphorylation of specific substrates in vivo. Mol Cell Proteomics 2003; 2:1217-24. [PMID: 14519720 DOI: 10.1074/mcp.m300078-mcp200] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Protein tyrosine phosphorylation controls diverse signaling pathways, and disregulated tyrosine kinase activity plays a direct role in human diseases such as cancer. Because activated kinases exert their effects by phosphorylating multiple substrate proteins, it is difficult or impossible to assess experimentally the contribution of a particular substrate to a cellular response or activity. To overcome this problem, we have developed a novel approach termed the "functional interaction trap," in which two proteins are induced to interact in a pairwise fashion through an engineered, highly specific binding interface. We show that the functional interaction trap can be used to direct a modified tyrosine kinase to specifically phosphorylate a single substrate of choice in vivo, permitting analysis of the resulting biological output. This strategy provides a powerful tool for validating the functional significance of tyrosine phosphorylation and other post-translational modifications identified by proteomic discovery efforts.
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Affiliation(s)
- Alok Sharma
- Department of Genetics and Developmental Biology, University of Connecticut Health Center, 263 Farmington Avenue, Farmington, CT 06030-3301, USA
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21
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Abstract
Previous surveys of radiation therapy among the Life Span Study (LSS) population at the Radiation Effects Research Foundation (RERF) revealed that 1,670 (1.4%) of the LSS participants received radiation treatments before 1984. The data on therapeutic radiation doses are indispensable for studying the relationship between radiation treatments and subsequent cancer occurrences. In this study, the radiation treatments were reproduced experimentally to determine the scattered radiation doses. The experiments were conducted using a female human phantom and various radiation sources, including a medium-voltage X-ray machine and a (60)Co gamma-ray source. Doses were measured using thermoluminescence dosimetry and ionization chambers. Radiation doses were determined for the salivary glands, thyroid gland, breast, lung, stomach, colon, ovary and active bone marrow. The results have been used for documenting the organ doses received by patients in previous surveys. The contribution of therapeutic irradiation to the occurrence of chromosome aberrations was studied using data on doses to active bone marrow from both radiation treatments and atomic bomb exposures in 26 RERF Adult Health Study participants. The results suggest that radiation treatments contributed to a large part of their frequencies of stable-type chromosome aberrations. The therapeutic radiation doses determined in the present study are available for investigating the effects of therapeutic irradiation on the subsequent primary cancers among atomic bomb survivors who received radiation treatments.
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Affiliation(s)
- K Kato
- Visiting Research Scientist, Department of Clinical Studies, Radiation Effects Research Foundation (RERF), 5-2 Hijiyama Park, Minami-ku, Hiroshima 732-0815, Japan.
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22
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Yamamoto F, Oka H, Antoku S, Ichiya Y, Masuda K, Maeda M. Synthesis and characterization of lipophilic 1-[18F]fluoroalkyl-2-nitroimidazoles for imaging hypoxia. Biol Pharm Bull 1999; 22:590-7. [PMID: 10408232 DOI: 10.1248/bpb.22.590] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
In order to develop new imaging markers for brain hypoxia, two lipophilic nitroimidazoles, 1-(3-fluoropropyl)-2-nitroimidazole (FPN) and 1-(8-fluorooctyl)-2-nitroimidazole (FON) were synthesized and labeled with fluorine-18. The octanol/water partition coefficients were measured as an indication of lipophilicity, giving values of logP=0.28 for FPN and logP=2.72 for FON, respectively, which are in the range thought to be optimal for the diffusion of molecules across the blood-brain barrier. It was suggested from a comparative study of in vitro radiosensitization in V79 cells that these lipophilic analogs may have reduction potentials close to those of fluoromisonidazole (FMISO) and misonidazole (MISO), known hypoxic cell radiosensitizers. The preparation of 18F-labeled FON (18FON) and FPN (18FPN) was achieved via two-steps through [18F]fluoride ion displacement of tosylate precursors, in reasonable radiochemical yields. Tissue distribution of 18FPN and 18FON in normal rats and tumor-bearing mice after intravenous injection was investigated and compared to the behavior of 18F-labeled FMISO (18FMISO), a proven hypoxic imaging agent. The high lipophilicity of 18FON and 18FPN resulted in increased initial uptake into normal rat brain, relative to 18FMISO, followed by a rapid washout from brain. Both of these lipophilic analogs had significantly lower tumor uptake and lower tumor-to-blood ratios than 18FMISO, suggestive of a poor trapping mechanism within the tumor tissue. Neither 18FON or 18FPN offers improved biological properties over 18FMISO as a potential agent for use in brain hypoxic imaging.
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Affiliation(s)
- F Yamamoto
- Faculty of Pharmaceutical Sciences and Faculty of Medicine, Kyushu University, Fukuoka, Japan
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23
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Zhu WG, Antoku S, Sasaki H, Dynlacht JR. Post-irradiation exposure to HBSS enhances apoptosis in FM3A cells. Anticancer Res 1998; 18:4043-9. [PMID: 9891443] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/09/2023]
Abstract
Many types of mammalian cells can repair potentially lethal damage (PLD) when incubated in conditioned medium (C-med) or Hank.'s balanced salt solution (HBSS) after irradiation. In this study, we found that there is an increase in clonogenic survival in FM3A cells, mouse mammary carcinoma cells when cells are incubated in C-med, but not in HBSS after irradiation. HBSS was lethal to unirradiated FM3A cells, and apoptosis was observed when cells were exposed to HBSS for more than 10 hours. However, irradiated cells underwent rapid apoptotic cell death and there was a decrease in clonogenic survival when cells were incubated in HBSS for a short time (3 h). Apoptotic cell death, was decreased significantly when irradiated cells were incubated in HBSS with 2% fetal calf serum. In addition, clonogenic survival was decreased significantly when irradiated cells were incubated in C-med with cycloheximide (CHX), an inhibitor of protein synthesis. Thus, the rapid apoptotic death of irradiated FM3A cells induced by HBSS might be due to the absence of serum or inhibition of protein synthesis. Some newly synthesized proteins, or proteins normally found in serum, may be required for irradiated cells to recover from X-ray induced damage.
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Affiliation(s)
- W G Zhu
- Department of Experimental Radiology, Faculty of Medicine, Kyushu University, Fukuoka, Japan.
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24
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Kato K, Antoku S, Russell WJ, Fujita S, Pinkston JA, Hayabuchi N, Hoshi M, Kodama K. Radiation therapy among atomic bomb survivors, Hiroshima and Nagasaki. Radiat Res 1998; 149:614-24. [PMID: 9611100] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
As a follow-up to the two previous surveys of radiation therapy among the atomic bomb survivors, a large-scale survey was performed to document (1) the number of radiation therapy treatments received by the atomic bomb survivors and (2) the types of radiation treatments conducted in Hiroshima and Nagasaki. The previous two surveys covered the radiation treatments among the Radiation Effects Research Foundation Adult Health Study (AHS) population, which is composed of 20,000 persons. In the present survey, the population was expanded to include the Life Span Study (LSS), including 93,611 atomic bomb survivors and 26,517 Hiroshima and Nagasaki citizens who were not in the cities at the times of the bombings. The LSS population includes the AHS population. The survey was conducted from 1981 to 1984. The survey teams reviewed all the medical records for radiation treatments of 24,266 patients at 11 large hospitals in Hiroshima and Nagasaki. Among them, the medical records for radiation treatments of 1556 LSS members were reviewed in detail. By analyzing the data obtained in the present and previous surveys, the number of patients receiving radiation therapy was estimated to be 4501 (3.7%) in the LSS population and 1026 (5.1%) in the AHS population between 1945-1980. During 1945-1965, 98% of radiation treatments used medium-voltage X rays, and 66% of the treatments were for benign diseases. During 1966-1980, 94% of the radiation treatments were for malignant neoplasms. During this period, 60Co gamma-ray exposure apparatus and high-energy electron accelerators were the prevalent mode of treatment in Hiroshima and in Nagasaki, respectively. The mean frequency of radiation therapy among the LSS population was estimated to have been 158 courses/year during 1945-1965 and 110 courses/year during 1966-1980. The present survey revealed that 377 AHS members received radiation therapy. The number was approximately twice the total number of cases found in the previous two surveys. Thus the data on radiation therapy in the AHS members have been updated well by this survey, and will provide information for more precise dose-response analyses of radiation effects in the AHS population. The information extracted from the medical records of the hospitals consisted of hospital names, treatment periods, body sites treated, diagnoses, treatment doses, radiation sources, the field sizes of the exposures and the data for identification of the patients. These data will be essential in estimating the organ doses from scattered radiation and in evaluating the effects of therapeutic radiation.
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Affiliation(s)
- K Kato
- Radiation Effects Research Foundation, and Suzugamine Women's College, Hiroshima, Japan
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25
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Antoku S, Aramaki R, Tanaka H, Kusumoto N. [Protection of cultured mammalian cells by rebamipide]. Fukuoka Igaku Zasshi 1997; 88:247-52. [PMID: 9248142] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Rebamipide which is used as a drug for gastritis and stomach ulcer has large capability for OH radical scavenging. It is expected that rebamipide has protective effect against ionizing radiations. The present paper deals with protective effect of rebamipide for cultured mammalian cells exposed to ionizing radiations. As rebamipide is insoluble in water, three solvents were used to dissolve. Rebamipide dissolved in dimethyl sulfoxide (DMSO), dimethyl formamide (DMFA) and 0.02 N NaOH was added to the cells in Eagle's minimum essential medium (MEM) supplemented with 10% fetal calf serum and the cells were irradiated with X-rays. After irradiation, the cells were trypsinized, plated in MEM with 10% fetal calf serum and incubated for 7 days in a CO2 incubator to form colonies. Rebamipide dissolved in 0.02 N NaOH exhibited the protective effect expected its OH radical scavenging capability. However, the protective effect of rebamipide dissolved in DMSO was about half of that expected by its radical scavenging capability and that of rebamipide dissolved in DMFA was not observed. Uptake of rebamipide labeled with 14C increased with increasing contact time with rebamipide. These rebamipide mainly distributed in nucleous rather than cytoplasm.
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Affiliation(s)
- S Antoku
- Department of Experimental Radiology, Faculty of Medicine, Kyushu University, Fukuoka
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26
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Abstract
Although it has been shown that proteases may play a positive role in in causing apoptosis of some cells, we report here that, on the contrary, protease inhibitors can promote heat-induced apoptosis in FM3A cells. Cysteine protease inhibitor, trans-Epoxy-succinyl-L-leucylamido-(4-guanidino)butane (E-64, 100 micrograms/ml) and aspartate protease inhibitor, pepstatin-A (100 micrograms/ml) were used to test hyperthermic effect on FM3A cells and showed remarkable cytotoxicity when they were present in cell suspension during heating at 44 degrees C. The cytotoxicity was due to promotion of heat-induced apoptosis as judged by DNA agarose electrophoresis. Furthermore, using flow cytometric analysis, we observed a decrease in the G0/G1 phase cell and an increase in the S phase cell as well as increased apoptosis after heat shock. E-64 and pepstatin-A exhibited a promotive effect on the changes of cell cycle induced by heat. The data presented suggest that the enhancement of hyperthermic cell killing by protease inhibitors may be related to promotion of heat-induced apoptosis and changes of cell cycle.
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Affiliation(s)
- W G Zhu
- Department of Experimental Radiology, Faculty of Medicine, Kyushu University, Fukuoka, Japan.
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27
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Zhu WG, Antoku S, Kura S, Aramaki R, Nakamura K, Sasaki H. Enhancement of hyperthermic killing in L5178Y cells by protease inhibitors. Cancer Res 1995; 55:739-42. [PMID: 7850783] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
We have investigated the effect of protease inhibitors on hyperthermic cell killing using cultured mammalian cells (L5178Y) and found that protease inhibitors were potent hyperthermia sensitizers. At 37 degrees C, phenylmethylsulfonyl fluoride (PMSF), a serine protease inhibitor, was not cytotoxic at the concentration of 400 micrograms/ml for up to 6 h. When cells were exposed to PMSF (200-400 micrograms/ml) during heating at 43 degrees C, significant potentiation of hyperthermic cell killing was observed. Other protease inhibitors, such as chymostatin and diisopropylfluorophosphate (both are serine protease inhibitors); (2S,3S)-trans-epoxy-succinyl-L-leucylamido-3-methylbutane ethyl ester (cysteine protease inhibitor) and pepstatin-A (aspartate protease inhibitor) showed similar effects. However, when cells were heated at 43 degrees C in the presence of cycloheximide (a protein synthesis inhibitor) together with PMSF, hyperthermic enhancement by PMSF decreased markedly. A decrease in potentiating the effect of PMSF was also noted with thermotolerant cells. These facts suggest that protease inhibitors may exert their hyperthermic cell killing by inhibiting proteases and ubiquitin, which are necessary to degrade denatured proteins induced by heat.
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Affiliation(s)
- W G Zhu
- Department of Experimental Radiology, Faculty of Medicine, Kyushu University, Fukuoka, Japan
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28
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Nakamura K, Antoku S. Enhancement of X-ray cell killing in cultured mammalian cells by the protein phosphatase inhibitor calyculin A. Cancer Res 1994; 54:2088-90. [PMID: 8174110] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Effects of calyculin A, a potent inhibitor of protein phosphatases 1 and 2A, on X-ray cell killing and chromatin structure were studied using cultured mammalian cells (BHK21). Calyculin A at concentrations of 2.5-20 nM enhanced X-ray cell killing when exponentially growing BHK21 cells were treated with calyculin A for 30 min after X-irradiation. A 30-min treatment with this drug induced chromatin condensation transiently. These results suggest that the enhancement of X-ray cell killing by calyculin A is caused by the events associated with chromatin condensation. Protein phosphatase-targeting drugs may represent a new class of radiation sensitizers.
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Affiliation(s)
- K Nakamura
- Department of Experimental Radiology, Faculty of Medicine, Kyushu University, Fukuoka, Japan
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29
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Nakamura K, Antoku S. Increase in postirradiation survival of rat 3Y1 fibroblasts by a protein kinase inhibitor, staurosporine. Cancer Biochem Biophys 1994; 14:15-21. [PMID: 7796385] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Protein kinases play an important role in the response of mammalian cells to ionizing radiation. In this study, we examined the effect of staurosporine, a potent inhibitor of protein kinases, on cell survival after X-irradiation, using the normal rat fibroblast line 3Y1. Treatment with 30 ng/ml staurosporine 1 h before irradiation resulted in the increase in survival of 3Y1 cells. This phenomenon was drug dose-dependent and maximal reduction of radiation-induced cell killing occurred when more than, or equal to, 30 ng/ml staurosporine was added. In contrast, treatment with 30 ng/ml staurosporine after irradiation did not increase cell survival. There was no change in cell cycle distribution by treatment for 1 h with 30 ng/ml staurosporine. These data suggest that the inhibition of protein kinase activities by staurosporine influences the radiosensitivity of 3Y1 cells.
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Affiliation(s)
- K Nakamura
- Department of Experimental Radiology, Faculty of Medicine, Kyushu University, Fukuoka, Japan
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30
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Nakamura K, Antoku S. Protein kinase inhibitor, staurosporine, prevents okadaic acid- or caffeine-induced chromosome condensation. In Vitro Cell Dev Biol Anim 1993; 29A:760-2. [PMID: 8118609 DOI: 10.1007/bf02634341] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
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31
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Nakamura K, Antoku S. Staurosporine induces multinucleation following chromosome decondensation in Colcemid-arrested cells. In Vitro Cell Dev Biol Anim 1993; 29A:525-7. [PMID: 8354662 DOI: 10.1007/bf02634144] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
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32
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Kato K, Antoku S, Sawada S, Russell WJ. Calibration of Mg2SiO4(Tb) thermoluminescent dosimeters for use in determining diagnostic x-ray doses to adult health study participants. Med Phys 1991; 18:928-33. [PMID: 1961156 DOI: 10.1118/1.596608] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Characteristics of Mg2SiO4(Tb) thermoluminescent dosimeters (TLD) were ascertained preparatory to measuring doses from diagnostic x-ray examinations received by Adult Health Study participants. These detectors are small, relatively sensitive to low-dose x-rays, and are appropriate for precise dosimetry. Extensive calibration is necessary for precisely determining doses according to their thermoluminescent intensities. Their sensitivities were investigated by dose, according to x-ray tube voltage, and by exposure direction, to obtain directional dependence. Dosimeter sensitivity lessened due to the fading effect and diminution of the planchet. However, these adverse effects can be avoided by storing the dosimeters at least 1.5 h and by using fresh silver-plated planchets. Thus the TLDs, for which sensitivities were determined in this study, will be useful in subsequent diagnostic x-ray dosimetry.
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Affiliation(s)
- K Kato
- Department of Clinical Studies, Radiation Effects Research Foundation, Hiroshima, Japan
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33
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Kazuo K, Antoku S, Sawada S, Russell WJ. Organ doses received by atomic bomb survivors during radiological examinations at the Radiation Effects Research Foundation. Br J Radiol 1991; 64:720-7. [PMID: 1884121 DOI: 10.1259/0007-1285-64-764-720] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
When evaluating the risks of oncogenesis and cancer mortality following exposure to the radiations of the atomic bombs (A-bombs), the medical X-ray doses received by the A-bomb survivors must also be estimated and considered. Using a human phantom, dosimetry was performed to estimate the X-ray doses received by A-bomb survivors during medical examinations at the Radiation Effects Research Foundation (RERF) as part of the long-term follow-up on the Adult Health Study (AHS). These examinations have been estimated to represent nearly 45% of the survivors' cumulative medical irradiation dose. Doses to the salivary glands, thyroid gland, lung, breast, stomach and colon were measured using thermoluminescent dosimeters. The results, which are reported here, will aid in estimating organ doses received by individual AHS participants.
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Affiliation(s)
- K Kazuo
- Department of Clinical Studies, Radiation Effects Research Foundation, Hiroshima, Japan
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34
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Kato K, Antoku S, Sawada S, Wada T, Russell WJ. Organ doses to atomic bomb survivors during photofluorography, fluoroscopy and computed tomography. Br J Radiol 1991; 64:728-33. [PMID: 1884122 DOI: 10.1259/0007-1285-64-764-728] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Doses to the salivary glands, thyroid gland, breast, lung, stomach and colon during mass radiological gastric screening, mass radiographic chest screening, upper gastrointestinal series and computed tomography were determined by exposing a female human phantom to simulated radiological X-ray examinations as performed in community hospitals. The doses were measured using thermoluminescent dosimeters, and the results will be used to document organ doses received by participants in the Atomic Bomb Casualty Commission/Radiation Effects Research Foundation Adult Health Study.
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Affiliation(s)
- K Kato
- Department of Clinical Studies, Radiation Effects Research Foundation, Hiroshima, Japan
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35
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Antoku S, Kura S. Enhancement of radiosensitivity of cultured mammalian cells by neocarzinostatin. II. Fixation of potentially lethal damage. Int J Radiat Biol 1990; 58:623-32. [PMID: 1976723 DOI: 10.1080/09553009014551981] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
The effects of neocarzinostatin (NCS), an anti-tumour drug, on the repair of potentially lethal damage (PLD) were studied using cultured Chinese hamster V79, malignant human melanoma and mouse lymphoma L5178Y cells in the stationary phase. The repair of PLD was observed in the melanoma and L5178Y cells but no such repair was observed in the V79 cells, when studied by delayed plating. NCS added to the culture medium immediately after X-irradiation evoked fixation of PLD within 10 min of the addition of NCS. The ratios of D0 values of the survival curves of the cells treated with NCS to those plated immediately after X-irradiation were 0.78, 0.88 and 0.85 for V79, melanoma and L5178Y cells, respectively. The extent of the fixation by NCS was similar to that caused by 0.5 M NaCl solution. The results in the present study and the inhibition of sublethal damage (SLD) by NCS reported previously, suggest that NCS might react with the DNA damage induced by radiation and modify it to lethal damage. The study indicates that SLD and PLD appear to be closely related to one another.
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Affiliation(s)
- S Antoku
- Department of Experimental Radiology, Faculty of Medicine, Kyushu University, Fukuoka, Japan
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36
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Antoku S, Kura S. Enhancement of radiosensitivity of cultured mammalian cells by neocarzinostatin. I. Inhibition of the repair of sublethal damage. Int J Radiat Biol 1990; 58:613-22. [PMID: 1976722 DOI: 10.1080/09553009014551971] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
The enhancement of radiosensitivity by neocarzinostatin (NCS), an antitumour drug, was studied using three strains of cultured mammalian cells with different repair capabilities for sublethal damage. NCS enhanced the radiosensitivity of the cells when applied both during and after X-irradiation under aerobic conditions. The enhancement ratios of NCS during X-irradiation were 1.25, 1.27 and 1.38 for mouse lymphoma L5178Y, Chinese hamster V79 and mouse mammary tumour FM 3A cells, respectively. The corresponding ratios after X-irradiation were 1.18, 1.27 and 1.38, respectively. These ratios were proportional to the repair capabilities of the cells for sublethal damage. NCS completely inhibited the repair of sublethal damage regardless of the repair capabilities of the cells for sublethal damage. NCS was equally effective for hypoxic cells. These results suggested that NCS enhanced the radiosensitivity of the cells probably by interacting with the residual damage after X-irradiation, thereby converting the sublethal damage or potentially lethal damage into lethal damage.
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Affiliation(s)
- S Antoku
- Department of Experimental Radiology, Faculty of Medicine, Kyushu University, Fukuoka, Japan
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37
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Antoku S, Hoshi M, Russell WJ, Kihara T, Sawada S, Takeshita K, Otake M, Yoshinaga H, Beach DR. Dental radiography exposure of the Hiroshima and Nagasaki populations. Oral Surg Oral Med Oral Pathol 1989; 67:354-60. [PMID: 2927931 DOI: 10.1016/0030-4220(89)90369-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Dental radiography doses in Hiroshima and Nagasaki were estimated on the basis of survey data from dental hospitals and clinics in Hiroshima and Nagasaki, and doses were measured by thermoluminescent dosimeters and a phantom. Doses to organs, including the lens, pituitary fossa, thyroid gland, and skin were calculated from data obtained during a 2-week survey in both cities. The mean caput doses were calculated from the data indicating frequency per year and were tabulated by organs, age, teeth examined, type of examination, population, sex, and city. No significant difference was observed by age, population, sex, or city. Currently the doses incurred during dental radiography may not be sufficiently high to cause bias in the assessments for late radiation effects among atomic-bomb survivors. However, the mean caput thyroid doses of 62 mrad and 67 mrad in Hiroshima and Nagasaki, respectively, cannot be ignored from the standpoint of their potential in contributing to radiation-induced carcinogenesis.
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Affiliation(s)
- S Antoku
- Division of Radiology, Radiation Effects Research Foundation, Hiroshima, Japan
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38
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Hoshi M, Antoku S, Nakamura N, Russell WJ, Miller RC, Sawada S, Mizuno M, Nishio S. Soft X-ray dosimetry and RBE for survival of Chinese hamster V79 cells. Int J Radiat Biol 1988; 54:577-91. [PMID: 2902156 DOI: 10.1080/09553008814552021] [Citation(s) in RCA: 29] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Dosimetry and biological effects of 40 and 50 keV low-energy X-rays generated by a SOFTEX Model CMBW-2 apparatus were studied. Doses were measured using a thin-window parallel-plate ionization chamber; beam quality was assessed using aluminum absorbers; exposure rates per unit current were determined according to the X-ray tube current and exposure times; and thermoluminescent (BeO chip) dosimeters were used to ascertain dose distributions in the irradiation field. The average correction factors for nonuniformity were calculated from the measured dose distributions. The means for ascertaining accurate exposures and doses using these methods are discussed. The dose-survival relationship of Chinese hamster V79 cells were assessed by irradiating them with 40 and 50 kV soft X-rays, 180 kV X-rays, and 60 Co gamma rays. Soft X-rays with three distinct effective energies were tested by changing the tube voltage kV and aluminium filter thicknesses; namely (1) 40 kV without filter, (2) 40 kV with a 0.2 mm thick aluminium filter and (3) 50 kV with a 0.7 mm thick aluminium filter. The effective energies obtained according to attenuation measurements using aluminium for these soft X-rays were 8.1, 11.7 and 18.5 kV, respectively. In this study the relative biological effectiveness (RBE) at 10 per cent survival compared with 60Co gamma rays ranged from 1.5 to 1.6. The RBE of 180 kV X-rays relative to 60Co gamma rays was 1.29. This study provided experimental data for the RBE of V79 cells in the intermediate energy range between hard and ultrasoft X-rays, data for which were previously reported by Goodhead and co-workers (1977, 1979, 1981).
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Affiliation(s)
- M Hoshi
- Research Institute for Nuclear Medicine and Biology, Hiroshima University, Japan
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39
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Antoku S, Hoshi M. Combined effects of radiosensitizers and radioprotectors on cultured mammalian cells to Co-60 gamma-rays. J Radiat Res 1984; 25:305-313. [PMID: 6442734 DOI: 10.1269/jrr.25.305] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
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40
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Abstract
The ability of WR-2721 to protect cultured mammalian cells against radiation-induced killing was nearly the same as that of cysteamine when WR-2721 was activated by mouse liver extract. Without the liver extract, protection by WR-2721 required long incubations with the cells prior to irradiation. The protective activity increased in proportion to the cell concentration. The dose reduction factor at a concentration of 4 mM WR-2721 was 1.11 and 1.41 for 1.5 X 10(5) cells/ml and 15 X 10(5) cells/ml of cultured cells, respectively. A non-protein bound sulfhydryl group was detected in cell suspensions after incubation with WR-2721, but it was not a dephosphorylated product of WR-2721.
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41
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Antoku S. Radiosensitization and radioprotection of E. coli by thiourea in nitrous oxide saturated suspensions. Int J Radiat Biol Relat Stud Phys Chem Med 1983; 43:451-8. [PMID: 6404849 DOI: 10.1080/09553008314550511] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
N2O did not modify the radiosensitivity of E. coli BH and H/r-30 strains as to colony-forming ability and DNA single-strand breaks. In N2O-saturated suspensions of E. coli, thiourea and thiosemicarbasite sensitized at low concentrations, while cysteamine and cysteine protected at all concentrations. Protection by thiourea in N2O-saturated suspensions was observed only in the frozen state. These results suggest that the conversion of e-aq to OH radicals may be responsible for sensitization and this sensitization is probably due to the thiourea and thiosemicarbasite radicals produced extracellularly.
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42
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Abstract
Conventional dental radiographic procedures do not permit direct visualization of the radiation field or the central ray. As a result, it is necessary to use a beam diameter larger than the film in order to prevent an unnecessarily high number of cone cuts or other errors during visual alignment of the cone and film. The modification of a conventional dental x-ray cone which permits the central ray to be depicted by a beam of light is described. The use of the device significantly reduced the number of cone cuts, even when small beam diameters were used. Visualization of the central ray improved radiographic accuracy and has the potential to significantly reduce the over-all dose to the population by reducing the size of the field used for dental radiography.
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Antoku S. [Modification of radiation damages (author's transl)]. Fukuoka Igaku Zasshi 1982; 73:71-5. [PMID: 7095724] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
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44
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Abstract
A second follow-up survey for radiation therapy exposure among a fixed cohort of A-bomb survivors originally numbering 20 000 persons identified 55 more who had received radiation therapy, and 7 more therapy-associated malignancies. In the previous and present investigations, 12 postirradiation malignancies were identified among 190 cohort members (6%) who received radiation therapy. This investigation underscored the necessity for documenting exposures to ionizing radiation for medical reasons, especially exposures incurring relatively high doses, among persons at relatively high risk of developing neoplasms, such as A-bomb survivors, and in malignancy epidemiology to exclude bias in estimates of risk.
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Antoku S. [Chemical radiosensitizers (author's transl)]. Radioisotopes 1979; 28:45-54. [PMID: 375322 DOI: 10.3769/radioisotopes.28.45] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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47
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Ueda E, Yoshida N, Nishimura K, Joh T, Antoku S. A semi-automated measurement of urinary catecholamines using high-speed ion-exchange column chromatography. Clin Chim Acta 1977; 80:447-53. [PMID: 912915 DOI: 10.1016/0009-8981(77)90137-1] [Citation(s) in RCA: 41] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Semi-automated measurement of urinary catecholamines, specific for dopa, noradrenaline, adrenaline and dopamine and other metabolites has been developed. Steps included alumina extraction, separation by high-speed ion-exchange column chromatography and fluorescent development by trihydroxyindole (THI) method without interference by other fluorescent substances. Recovery, reproducibility and sensitivity were satisfactory. alpha-Methyldopa, a metabolite of alpha-methyldopa, and isoproterenol were separated completely without interfering with the measurement of noradrenaline, adrenaline and dopamine.
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48
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Antoku S. DNA single-strand breaks of preheated cultured mammalian cells irradiated under nitrogen- and nitrous oxide-saturated conditions. Radiat Res 1977; 71:678-82. [PMID: 897092] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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49
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Antoku S, Gholipour-Khalili K. Effect of oxygen on bacteria and cultured mammalian cells irradiated in the frozen state. Int J Radiat Biol Relat Stud Phys Chem Med 1977; 32:145-52. [PMID: 330428 DOI: 10.1080/09553007714550821] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The oxygen effect for bacteria and cultured mammalian cells at -196 degrees C was studied, using suspensions to which were added cryoprotective and chemical protective agents. The oxygen enhancement ratio (o.e.r.) in the frozen state was dependent on the chemicals added to the suspensions. When the chemicals had a high competitive reactivity with oxygen to the damage, the o.e.r. in the frozen state was comparable to that in the liquid suspensions. Without chemicals, the o.e.r. in the frozen state decreased significantly, probably because of the low competitive activity of endogenous SH compounds. In general, the systems with a higher o.e.r. in the liquid state had a lower o.e.r. in the frozen state.
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Gholipour-Khalili K, Antoku S, Sunayashiki T, Takeshita K. Dosimetry of fast neutrons from T (d, n) reaction neutron generator. Nihon Igaku Hoshasen Gakkai Zasshi 1977; 37:815-20. [PMID: 917752] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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