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Trujillo AS, Hsu KH, Viswanathan MC, Cammarato A, Bernstein SI. The R369 Myosin Residue within Loop 4 Is Critical for Actin Binding and Muscle Function in Drosophila. Int J Mol Sci 2022; 23:ijms23052533. [PMID: 35269675 PMCID: PMC8910226 DOI: 10.3390/ijms23052533] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2022] [Revised: 02/16/2022] [Accepted: 02/17/2022] [Indexed: 02/06/2023] Open
Abstract
The myosin molecular motor interacts with actin filaments in an ATP-dependent manner to yield muscle contraction. Myosin heavy chain residue R369 is located within loop 4 at the actin-tropomyosin interface of myosin's upper 50 kDa subdomain. To probe the importance of R369, we introduced a histidine mutation of that residue into Drosophila myosin and implemented an integrative approach to determine effects at the biochemical, cellular, and whole organism levels. Substituting the similarly charged but bulkier histidine residue reduces maximal actin binding in vitro without affecting myosin ATPase activity. R369H mutants exhibit impaired flight ability that is dominant in heterozygotes and progressive with age in homozygotes. Indirect flight muscle ultrastructure is normal in mutant homozygotes, suggesting that assembly defects or structural deterioration of myofibrils are not causative of reduced flight. Jump ability is also reduced in homozygotes. In contrast to these skeletal muscle defects, R369H mutants show normal heart ultrastructure and function, suggesting that this residue is differentially sensitive to perturbation in different myosin isoforms or muscle types. Overall, our findings indicate that R369 is an actin binding residue that is critical for myosin function in skeletal muscles, and suggest that more severe perturbations at this residue may cause human myopathies through a similar mechanism.
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Affiliation(s)
- Adriana S. Trujillo
- Department of Biology, Molecular Biology Institute, Heart Institute, San Diego State University, San Diego, CA 92182, USA; (A.S.T.); (K.H.H.)
| | - Karen H. Hsu
- Department of Biology, Molecular Biology Institute, Heart Institute, San Diego State University, San Diego, CA 92182, USA; (A.S.T.); (K.H.H.)
| | - Meera C. Viswanathan
- Department of Medicine, Division of Cardiology, Johns Hopkins University, Baltimore, MD 21205, USA; (M.C.V.); (A.C.)
| | - Anthony Cammarato
- Department of Medicine, Division of Cardiology, Johns Hopkins University, Baltimore, MD 21205, USA; (M.C.V.); (A.C.)
| | - Sanford I. Bernstein
- Department of Biology, Molecular Biology Institute, Heart Institute, San Diego State University, San Diego, CA 92182, USA; (A.S.T.); (K.H.H.)
- Correspondence:
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2
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Trujillo AS, Hsu KH, Puthawala J, Viswanathan MC, Loya A, Irving TC, Cammarato A, Swank DM, Bernstein SI. Myosin dilated cardiomyopathy mutation S532P disrupts actomyosin interactions, leading to altered muscle kinetics, reduced locomotion, and cardiac dilation in Drosophila. Mol Biol Cell 2021; 32:1690-1706. [PMID: 34081531 PMCID: PMC8684735 DOI: 10.1091/mbc.e21-02-0088] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [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] [Indexed: 12/27/2022] Open
Abstract
Dilated cardiomyopathy (DCM), a life-threatening disease characterized by pathological heart enlargement, can be caused by myosin mutations that reduce contractile function. To better define the mechanistic basis of this disease, we employed the powerful genetic and integrative approaches available in Drosophila melanogaster. To this end, we generated and analyzed the first fly model of human myosin-induced DCM. The model reproduces the S532P human β-cardiac myosin heavy chain DCM mutation, which is located within an actin-binding region of the motor domain. In concordance with the mutation's location at the actomyosin interface, steady-state ATPase and muscle mechanics experiments revealed that the S532P mutation reduces the rates of actin-dependent ATPase activity and actin binding and increases the rate of actin detachment. The depressed function of this myosin form reduces the number of cross-bridges during active wing beating, the power output of indirect flight muscles, and flight ability. Further, S532P mutant hearts exhibit cardiac dilation that is mutant gene dose-dependent. Our study shows that Drosophila can faithfully model various aspects of human DCM phenotypes and suggests that impaired actomyosin interactions in S532P myosin induce contractile deficits that trigger the disease.
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Affiliation(s)
- Adriana S Trujillo
- Department of Biology, Molecular Biology Institute, Heart Institute, San Diego State University, San Diego, CA 92182
| | - Karen H Hsu
- Department of Biology, Molecular Biology Institute, Heart Institute, San Diego State University, San Diego, CA 92182
| | - Joy Puthawala
- Department of Biological Sciences and Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, NY 12180
| | - Meera C Viswanathan
- Division of Cardiology, Department of Medicine, Johns Hopkins University, Baltimore, MD 21205
| | - Amy Loya
- Department of Biological Sciences and Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, NY 12180
| | - Thomas C Irving
- Center for Synchrotron Radiation Research and Instrumentation and Department of Biological Sciences, Illinois Institute of Technology, Chicago, IL 60616
| | - Anthony Cammarato
- Division of Cardiology, Department of Medicine, Johns Hopkins University, Baltimore, MD 21205
| | - Douglas M Swank
- Department of Biological Sciences and Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, NY 12180
| | - Sanford I Bernstein
- Department of Biology, Molecular Biology Institute, Heart Institute, San Diego State University, San Diego, CA 92182
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Konstantinidis K, Bezzerides VJ, Lai L, Isbell HM, Wei AC, Wu Y, Viswanathan MC, Blum ID, Granger JM, Heims-Waldron D, Zhang D, Luczak ED, Murphy KR, Lu F, Gratz DH, Manta B, Wang Q, Wang Q, Kolodkin AL, Gladyshev VN, Hund TJ, Pu WT, Wu MN, Cammarato A, Bianchet MA, Shea MA, Levine RL, Anderson ME. MICAL1 constrains cardiac stress responses and protects against disease by oxidizing CaMKII. J Clin Invest 2021; 130:4663-4678. [PMID: 32749237 PMCID: PMC7456244 DOI: 10.1172/jci133181] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [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: 09/04/2019] [Accepted: 05/29/2020] [Indexed: 01/22/2023] Open
Abstract
Oxidant stress can contribute to health and disease. Here we show that invertebrates and vertebrates share a common stereospecific redox pathway that protects against pathological responses to stress, at the cost of reduced physiological performance, by constraining Ca2+/calmodulin-dependent protein kinase II (CaMKII) activity. MICAL1, a methionine monooxygenase thought to exclusively target actin, and MSRB, a methionine reductase, control the stereospecific redox status of M308, a highly conserved residue in the calmodulin-binding (CaM-binding) domain of CaMKII. Oxidized or mutant M308 (M308V) decreased CaM binding and CaMKII activity, while absence of MICAL1 in mice caused cardiac arrhythmias and premature death due to CaMKII hyperactivation. Mimicking the effects of M308 oxidation decreased fight-or-flight responses in mice, strikingly impaired heart function in Drosophila melanogaster, and caused disease protection in human induced pluripotent stem cell-derived cardiomyocytes with catecholaminergic polymorphic ventricular tachycardia, a CaMKII-sensitive genetic arrhythmia syndrome. Our studies identify a stereospecific redox pathway that regulates cardiac physiological and pathological responses to stress across species.
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Affiliation(s)
- Klitos Konstantinidis
- Division of Cardiology.,Department of Medicine, Johns Hopkins University, Baltimore, Maryland, USA
| | | | - Lo Lai
- Laboratory of Biochemistry, National Heart, Lung, and Blood Institute, Bethesda, Maryland, USA
| | - Holly M Isbell
- Department of Biochemistry, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
| | - An-Chi Wei
- Department of Electrical Engineering, Graduate Institute of Biomedical and Bioinformatics, National Taiwan University, Taipei City, Taiwan
| | - Yuejin Wu
- Department of Medicine, Johns Hopkins University, Baltimore, Maryland, USA
| | - Meera C Viswanathan
- Division of Cardiology.,Department of Medicine, Johns Hopkins University, Baltimore, Maryland, USA
| | - Ian D Blum
- Department of Neurology, Johns Hopkins University, Baltimore, Maryland, USA
| | - Jonathan M Granger
- Department of Medicine, Johns Hopkins University, Baltimore, Maryland, USA
| | | | - Donghui Zhang
- Department of Cardiology, Boston Children's Hospital, Boston, Massachusetts, USA.,State Key Laboratory of Biocatalysis and Enzyme Engineering, School of Life Science, Hubei University, Wuhan, China
| | - Elizabeth D Luczak
- Department of Medicine, Johns Hopkins University, Baltimore, Maryland, USA
| | - Kevin R Murphy
- Department of Medicine, Johns Hopkins University, Baltimore, Maryland, USA
| | - Fujian Lu
- Department of Cardiology, Boston Children's Hospital, Boston, Massachusetts, USA
| | - Daniel H Gratz
- Frick Center for Heart Failure and Arrhythmia, Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, Ohio, USA.,Department of Biomedical Engineering, College of Engineering, The Ohio State University, Columbus, Ohio, USA
| | - Bruno Manta
- Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Qiang Wang
- Department of Neurology, Zhongshan Hospital, Fudan University, Shanghai, China
| | - Qinchuan Wang
- Department of Medicine, Johns Hopkins University, Baltimore, Maryland, USA
| | - Alex L Kolodkin
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University, Maryland, USA
| | - Vadim N Gladyshev
- Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Thomas J Hund
- Frick Center for Heart Failure and Arrhythmia, Dorothy M. Davis Heart and Lung Research Institute, The Ohio State University Wexner Medical Center, Columbus, Ohio, USA.,Department of Biomedical Engineering, College of Engineering, The Ohio State University, Columbus, Ohio, USA
| | - William T Pu
- Department of Cardiology, Boston Children's Hospital, Boston, Massachusetts, USA.,Harvard Stem Cell Institute, Cambridge, Massachusetts, USA
| | - Mark N Wu
- Department of Medicine, Johns Hopkins University, Baltimore, Maryland, USA.,Department of Neurology, Johns Hopkins University, Baltimore, Maryland, USA.,Solomon H. Snyder Department of Neuroscience, Johns Hopkins University, Maryland, USA.,Department of Genetic Medicine
| | - Anthony Cammarato
- Division of Cardiology.,Department of Medicine, Johns Hopkins University, Baltimore, Maryland, USA.,Department of Physiology, and
| | - Mario A Bianchet
- Department of Neurology, Johns Hopkins University, Baltimore, Maryland, USA.,Department of Biophysics and Biophysical Chemistry, Johns Hopkins University, Baltimore, Maryland, USA
| | - Madeline A Shea
- Department of Biochemistry, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
| | - Rodney L Levine
- Laboratory of Biochemistry, National Heart, Lung, and Blood Institute, Bethesda, Maryland, USA
| | - Mark E Anderson
- Division of Cardiology.,Department of Medicine, Johns Hopkins University, Baltimore, Maryland, USA.,Department of Physiology, and
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4
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Madan A, Viswanathan MC, Woulfe KC, Schmidt W, Sidor A, Liu T, Nguyen TH, Trinh B, Wilson C, Madathil S, Vogler G, O'Rourke B, Biesiadecki BJ, Tobacman LS, Cammarato A. TNNT2 mutations in the tropomyosin binding region of TNT1 disrupt its role in contractile inhibition and stimulate cardiac dysfunction. Proc Natl Acad Sci U S A 2020; 117:18822-18831. [PMID: 32690703 PMCID: PMC7414051 DOI: 10.1073/pnas.2001692117] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [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] [Indexed: 01/03/2023] Open
Abstract
Muscle contraction is regulated by the movement of end-to-end-linked troponin-tropomyosin complexes over the thin filament surface, which uncovers or blocks myosin binding sites along F-actin. The N-terminal half of troponin T (TnT), TNT1, independently promotes tropomyosin-based, steric inhibition of acto-myosin associations, in vitro. Recent structural models additionally suggest TNT1 may restrain the uniform, regulatory translocation of tropomyosin. Therefore, TnT potentially contributes to striated muscle relaxation; however, the in vivo functional relevance and molecular basis of this noncanonical role remain unclear. Impaired relaxation is a hallmark of hypertrophic and restrictive cardiomyopathies (HCM and RCM). Investigating the effects of cardiomyopathy-causing mutations could help clarify TNT1's enigmatic inhibitory property. We tested the hypothesis that coupling of TNT1 with tropomyosin's end-to-end overlap region helps anchor tropomyosin to an inhibitory position on F-actin, where it deters myosin binding at rest, and that, correspondingly, cross-bridge cycling is defectively suppressed under diastolic/low Ca2+ conditions in the presence of HCM/RCM lesions. The impact of TNT1 mutations on Drosophila cardiac performance, rat myofibrillar and cardiomyocyte properties, and human TNT1's propensity to inhibit myosin-driven, F-actin-tropomyosin motility were evaluated. Our data collectively demonstrate that removing conserved, charged residues in TNT1's tropomyosin-binding domain impairs TnT's contribution to inhibitory tropomyosin positioning and relaxation. Thus, TNT1 may modulate acto-myosin activity by optimizing F-actin-tropomyosin interfacial contacts and by binding to actin, which restrict tropomyosin's movement to activating configurations. HCM/RCM mutations, therefore, highlight TNT1's essential role in contractile regulation by diminishing its tropomyosin-anchoring effects, potentially serving as the initial trigger of pathology in our animal models and humans.
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Affiliation(s)
- Aditi Madan
- Department of Medicine, Division of Cardiology, Johns Hopkins University, Baltimore, MD 21205
| | - Meera C Viswanathan
- Department of Medicine, Division of Cardiology, Johns Hopkins University, Baltimore, MD 21205
| | - Kathleen C Woulfe
- Department of Medicine, Division of Cardiology, University of Colorado Denver, Aurora, CO 80045
| | - William Schmidt
- Department of Medicine, Division of Cardiology, Johns Hopkins University, Baltimore, MD 21205
| | - Agnes Sidor
- Department of Medicine, Division of Cardiology, Johns Hopkins University, Baltimore, MD 21205
| | - Ting Liu
- Department of Medicine, Division of Cardiology, Johns Hopkins University, Baltimore, MD 21205
| | - Tran H Nguyen
- Department of Medicine, Division of Cardiology, Johns Hopkins University, Baltimore, MD 21205
| | - Bosco Trinh
- Development, Aging and Regeneration Program, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA 92037
| | - Cortney Wilson
- Department of Medicine, Division of Cardiology, University of Colorado Denver, Aurora, CO 80045
| | - Sineej Madathil
- Department of Medicine, University of Illinois College of Medicine, Chicago, IL 60612
| | - Georg Vogler
- Development, Aging and Regeneration Program, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA 92037
| | - Brian O'Rourke
- Department of Medicine, Division of Cardiology, Johns Hopkins University, Baltimore, MD 21205
| | - Brandon J Biesiadecki
- Department of Physiology and Cell Biology, The Ohio State University, Columbus, OH 43210
- The Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH 43210
| | - Larry S Tobacman
- Department of Medicine, University of Illinois College of Medicine, Chicago, IL 60612
| | - Anthony Cammarato
- Department of Medicine, Division of Cardiology, Johns Hopkins University, Baltimore, MD 21205;
- Department of Physiology, Johns Hopkins University, Baltimore, MD 21205
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5
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Viswanathan MC, Schmidt W, Franz P, Rynkiewicz MJ, Newhard CS, Madan A, Lehman W, Swank DM, Preller M, Cammarato A. A role for actin flexibility in thin filament-mediated contractile regulation and myopathy. Nat Commun 2020; 11:2417. [PMID: 32415060 PMCID: PMC7229152 DOI: 10.1038/s41467-020-15922-5] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [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: 01/04/2019] [Accepted: 03/30/2020] [Indexed: 12/20/2022] Open
Abstract
Striated muscle contraction is regulated by the translocation of troponin-tropomyosin strands over the thin filament surface. Relaxation relies partly on highly-favorable, conformation-dependent electrostatic contacts between actin and tropomyosin, which position tropomyosin such that it impedes actomyosin associations. Impaired relaxation and hypercontractile properties are hallmarks of various muscle disorders. The α-cardiac actin M305L hypertrophic cardiomyopathy-causing mutation lies near residues that help confine tropomyosin to an inhibitory position along thin filaments. Here, we investigate M305L actin in vivo, in vitro, and in silico to resolve emergent pathological properties and disease mechanisms. Our data suggest the mutation reduces actin flexibility and distorts the actin-tropomyosin electrostatic energy landscape that, in muscle, result in aberrant contractile inhibition and excessive force. Thus, actin flexibility may be required to establish and maintain interfacial contacts with tropomyosin as well as facilitate its movement over distinct actin surface features and is, therefore, likely necessary for proper regulation of contraction. The α-cardiac actin M305L hypertrophic cardiomyopathy-causing mutation is located near residues that help confine tropomyosin to an inhibitory position along thin filaments. Here the authors assessed M305L actin in vivo, in vitro, and in silico to characterize emergent pathological properties and define the mechanistic basis of disease.
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Affiliation(s)
- Meera C Viswanathan
- Department of Medicine, Division of Cardiology, Johns Hopkins University, 720 Rutland Avenue, Baltimore, MD, 21205, USA
| | - William Schmidt
- Department of Medicine, Division of Cardiology, Johns Hopkins University, 720 Rutland Avenue, Baltimore, MD, 21205, USA
| | - Peter Franz
- Institute for Biophysical Chemistry, Hannover Medical School, Carl-Neuberg-Straße 1, 30625, Hannover, Germany
| | - Michael J Rynkiewicz
- Department of Physiology and Biophysics, Boston University School of Medicine, 700 Albany Street St, Boston, MA, 02118, USA
| | - Christopher S Newhard
- Department of Biological Sciences and Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, 110 8th Street, Troy, NY, 12180-3590, USA
| | - Aditi Madan
- Department of Medicine, Division of Cardiology, Johns Hopkins University, 720 Rutland Avenue, Baltimore, MD, 21205, USA
| | - William Lehman
- Department of Physiology and Biophysics, Boston University School of Medicine, 700 Albany Street St, Boston, MA, 02118, USA
| | - Douglas M Swank
- Department of Biological Sciences and Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, 110 8th Street, Troy, NY, 12180-3590, USA
| | - Matthias Preller
- Institute for Biophysical Chemistry, Hannover Medical School, Carl-Neuberg-Straße 1, 30625, Hannover, Germany.
| | - Anthony Cammarato
- Department of Medicine, Division of Cardiology, Johns Hopkins University, 720 Rutland Avenue, Baltimore, MD, 21205, USA. .,Department of Physiology, Johns Hopkins University School of Medicine, 720 Rutland Avenue, Baltimore, MD, 21205, USA.
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6
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Wang Q, Hernandez-Ochoa EO, Blum ID, Granger JM, Yang J, Viswanathan MC, Aja S, Liu N, Antonescu CM, Florea LD, Conover Talbot C, Mohr D, Wagner KR, Regot S, Lovering RM, Wu MN, Cammarato AR, Schneider MF, Bever GS, Anderson ME. CaMKII oxidation is a performance-disease tradeoff in vertebrate evolution. J Mol Cell Cardiol 2020. [DOI: 10.1016/j.yjmcc.2019.11.055] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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7
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Madan A, Viswanathan MC, Woulfe KC, Schmidt WM, Vogler G, Wilson C, Madathil S, Biesiadecki BJ, Trinh B, Sidor A, Liu T, O'Rourke B, Tobacman LS, Cammarato A. Mutations in the TnT1 Tropomyosin-Binding Element of Troponin-T Alter Its Inhibitory Properties and Stimulate Myocardial Dysfunction. Biophys J 2020. [DOI: 10.1016/j.bpj.2019.11.2384] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022] Open
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8
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Limpitikul WB, Viswanathan MC, O'Rourke B, Yue DT, Cammarato A. L-Type Calcium Channels are a Major Source of Plasmalemmel Calcium Influx for Drosophila Cardiomyocytes. Biophys J 2019. [DOI: 10.1016/j.bpj.2018.11.848] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022] Open
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9
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Viswanathan MC. Expression of Myosin Storage Myopathy Mutations in Drosophila Disrupts Skeletal and Cardiac Muscle Structure and Function. Biophys J 2019. [DOI: 10.1016/j.bpj.2018.11.2089] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022] Open
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10
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Madan A, Viswanathan MC, Vogler G, Woulfe KC, Schmidt W, Trinh B, Madathil S, Wilson C, Tobacman LS, Cammarato A. Troponin-T Cardiomyopathy Mutations Depress its Inhibitory Properties, In Vitro, and Stimulate Myocardial Dysfunction, In Vivo. Biophys J 2019. [DOI: 10.1016/j.bpj.2018.11.643] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022] Open
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11
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Blice-Baum AC, Vogler G, Viswanathan MC, Trinh B, Limpitikul WB, Cammarato A. Quantifying Tissue-Specific Overexpression of FOXO in Drosophila via mRNA Fluorescence In Situ Hybridization Using Branched DNA Probe Technology. Methods Mol Biol 2019; 1890:171-190. [PMID: 30414154 PMCID: PMC7906431 DOI: 10.1007/978-1-4939-8900-3_15] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [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] [Indexed: 12/12/2022]
Abstract
While the highly conserved FOXO transcription factors have been studied in Drosophila melanogaster for decades, the ability to accurately control and measure their tissue-specific expression is often cumbersome due to a lack of reagents and to limited, nonhomogeneous samples. The need for quantitation within a distinct cell type is particularly important because transcription factors must be expressed in specific amounts to perform their functions properly. However, the inherent heterogeneity of many samples can make evaluating cell-specific FOXO and/or FOXO load difficult. Here, we describe an extremely sensitive fluorescence in situ hybridization (FISH) approach for visualizing and quantifying multiple mRNAs with single-cell resolution in adult Drosophila cardiomyocytes. The procedure relies upon branched DNA technology, which allows several fluorescent molecules to label an individual transcript, drastically increasing the signal-to-noise ratio compared to other FISH assays. This protocol can be modified for use in various small animal models, tissue types, and for assorted nucleic acids.
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Affiliation(s)
- Anna C Blice-Baum
- Division of Cardiology, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
- Science Department, Iadarola Center for Science, Education and Technology, Cabrini University, Radnor, PA, USA.
| | - Georg Vogler
- Development, Aging and Regeneration Program, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA, USA.
| | - Meera C Viswanathan
- Division of Cardiology, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Bosco Trinh
- Development, Aging and Regeneration Program, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA, USA
| | - Worawan B Limpitikul
- Department of Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Anthony Cammarato
- Division of Cardiology, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA
- Department of Physiology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
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12
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Kronert WA, Bell KM, Viswanathan MC, Melkani GC, Trujillo AS, Huang A, Melkani A, Cammarato A, Swank DM, Bernstein SI. Prolonged cross-bridge binding triggers muscle dysfunction in a Drosophila model of myosin-based hypertrophic cardiomyopathy. eLife 2018; 7:38064. [PMID: 30102150 PMCID: PMC6141233 DOI: 10.7554/elife.38064] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2018] [Accepted: 08/10/2018] [Indexed: 01/08/2023] Open
Abstract
K146N is a dominant mutation in human β-cardiac myosin heavy chain, which causes hypertrophic cardiomyopathy. We examined how Drosophila muscle responds to this mutation and integratively analyzed the biochemical, physiological and mechanical foundations of the disease. ATPase assays, actin motility, and indirect flight muscle mechanics suggest at least two rate constants of the cross-bridge cycle are altered by the mutation: increased myosin attachment to actin and decreased detachment, yielding prolonged binding. This increases isometric force generation, but also resistive force and work absorption during cyclical contractions, resulting in decreased work, power output, flight ability and degeneration of flight muscle sarcomere morphology. Consistent with prolonged cross-bridge binding serving as the mechanistic basis of the disease and with human phenotypes, 146N/+ hearts are hypercontractile with increased tension generation periods, decreased diastolic/systolic diameters and myofibrillar disarray. This suggests that screening mutated Drosophila hearts could rapidly identify hypertrophic cardiomyopathy alleles and treatments. Myosin is a motor protein that drives the contraction of muscles. Filaments made from myosin molecules slide between filaments of another protein called actin, tugging the edges of the muscle cell inwards. To achieve this, part of each motor protein – called the 'head' – grabs hold of actin and uses energy to pull on the filaments. Small genetic mutations in the gene for myosin can change the shape of the protein. This can change the way that it interacts with actin, altering the molecular machinery that makes muscles contract. In some cases, gene errors can cause the heart muscle wall to thicken, a condition called hypertrophic cardiomyopathy. Mapping the locations of known mutations revealed 'hot spots' on the myosin protein where these errors are likely to cause disease. These include the part of the molecule that swings the myosin heads, and the heads themselves. It only takes a change to a single letter in the DNA code to thicken the heart wall, but the impact of each possible change is not yet known. Kronert et al. have now genetically modified fruit flies to give them one of the mutations that causes thickening of the heart wall in humans. The mutation, known as K146N, does not appear in one of the well-known 'hot spots'. The experiments revealed that the mutation causes myosin to remain attached to actin for longer than normal. This increased the amount of force the myosin generated, but slowed down actin movement, causing muscle stiffness. This resulted in less power for every cycle of muscle movement, and caused the muscles to degenerate over time. As a result, the flies were less able to use their wings, and their hearts pumped less well. Hypertrophic cardiomyopathy can cause death in young adults, particularly competitive athletes. Yet studying the disease in humans is challenging. Recreating myosin mutations in fruit flies provides a way to study hypertrophic cardiomyopathy in the laboratory. In the future, extensions to this technique could allow researchers to examine the impact of other mutations. Models like this one could also allow early testing of new drugs or genetic treatments to repair faulty myosin molecules.
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Affiliation(s)
- William A Kronert
- Department of Biology, Molecular Biology Institute and Heart Institute, San Diego State University, San Diego, United States
| | - Kaylyn M Bell
- Department of Biology and Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, New York, United States
| | - Meera C Viswanathan
- Department of Medicine, Division of Cardiology, Johns Hopkins University, Baltimore, United States
| | - Girish C Melkani
- Department of Biology, Molecular Biology Institute and Heart Institute, San Diego State University, San Diego, United States
| | - Adriana S Trujillo
- Department of Biology, Molecular Biology Institute and Heart Institute, San Diego State University, San Diego, United States
| | - Alice Huang
- Department of Biology and Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, New York, United States
| | - Anju Melkani
- Department of Biology, Molecular Biology Institute and Heart Institute, San Diego State University, San Diego, United States
| | - Anthony Cammarato
- Department of Medicine, Division of Cardiology, Johns Hopkins University, Baltimore, United States
| | - Douglas M Swank
- Department of Biology and Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, New York, United States.,Department of Biomedical Engineering, Rensselaer Polytechnic Institute, New York, United States
| | - Sanford I Bernstein
- Department of Biology, Molecular Biology Institute and Heart Institute, San Diego State University, San Diego, United States
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13
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Brody MJ, Vanhoutte D, Viswanathan MC, Nguyen T, Maillet M, York AJ, Sargent MA, Cammarato A, Molkentin JD. Abstract 548: Evolutionarily Conserved Functions for Valosin Containing Protein (VCP) in Cardiac and Skeletal Muscle Reveal Mechanistic Insights into Multisystem Proteinopathy. Circ Res 2018. [DOI: 10.1161/res.123.suppl_1.548] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Valosin Containing Protein (VCP)/p97 is a AAA-ATPase with functions in vast cellular protein quality control processes, including targeting of misfolded or aggregated proteins for degradation by the ubiquitin proteasome system and autophagy. Mutations in VCP cause a multisystem degenerative proteinopathy disorder that includes pathologies of the nervous system, skeletal muscle, bone, and heart. However, the molecular function of VCP in myocytes is unknown. We generated cardiomyocyte-specific transgenic mice overexpressing wildtype VCP or a VCP
K524A
mutant with deficient ATPase activity. Mice overexpressing wildtype VCP exhibit normal cardiac structure and function while mutant VCP overexpressing mice develop cardiomyopathy and have elevated levels of ubiquitinated proteins in the heart. Additionally, we generated transgenic flies overexpressing wildtype VCP or VCP
K524A
in muscle. Flies overexpressing the VCP ATPase-deficient mutant have reduced flight ability at two days of age and are unable to fly at seven days of age, suggesting conserved indispensable homeostatic functions for VCP in heart and skeletal muscle. Moreover, mouse hearts and
Drosophila
indirect flight muscle overexpressing the ATPase-deficient VCP mutant exhibit profound ultrastructural abnormalities consistent with dysregulation of proteostasis. Extensive proteomics in
Drosophila
and in mouse heart identified conserved interactions of VCP with protein complexes that suggest unique functions for VCP in regulating novel quality control pathways in muscle. These data and novel regulatory relationships will be presented, which implicate important and evolutionarily conserved functions for VCP and suggest molecular mechanisms that underlie the molecular etiology of multisystem proteinopathy disorders.
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Affiliation(s)
| | | | | | | | | | - Allen J York
- Cincinnati Childrens Hosp, Howard Hughes Med Institute, Cincinnati, OH
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14
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Viswanathan MC, Tham RC, Kronert WA, Sarsoza F, Trujillo AS, Cammarato A, Bernstein SI. Myosin storage myopathy mutations yield defective myosin filament assembly in vitro and disrupted myofibrillar structure and function in vivo. Hum Mol Genet 2018; 26:4799-4813. [PMID: 28973424 DOI: 10.1093/hmg/ddx359] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2017] [Accepted: 09/11/2017] [Indexed: 12/19/2022] Open
Abstract
Myosin storage myopathy (MSM) is a congenital skeletal muscle disorder caused by missense mutations in the β-cardiac/slow skeletal muscle myosin heavy chain rod. It is characterized by subsarcolemmal accumulations of myosin that have a hyaline appearance. MSM mutations map near or within the assembly competence domain known to be crucial for thick filament formation. Drosophila MSM models were generated for comprehensive physiological, structural, and biochemical assessment of the mutations' consequences on muscle and myosin structure and function. L1793P, R1845W, and E1883K MSM mutant myosins were expressed in an indirect flight (IFM) and jump muscle myosin null background to study the effects of these variants without confounding influences from wild-type myosin. Mutant animals displayed highly compromised jump and flight ability, disrupted muscle proteostasis, and severely perturbed IFM structure. Electron microscopy revealed myofibrillar disarray and degeneration with hyaline-like inclusions. In vitro assembly assays demonstrated a decreased ability of mutant myosin to polymerize, with L1793P filaments exhibiting shorter lengths. In addition, limited proteolysis experiments showed a reduced stability of L1793P and E1883K filaments. We conclude that the disrupted hydropathy or charge of residues in the heptad repeat of the mutant myosin rods likely alters interactions that stabilize coiled-coil dimers and thick filaments, causing disruption in ordered myofibrillogenesis and/or myofibrillar integrity, and the consequent myosin aggregation. Our Drosophila models are the first to recapitulate the human MSM phenotype with ultrastructural inclusions, suggesting that the diminished ability of the mutant myosin to form stable thick filaments contributes to the dystrophic phenotype observed in afflicted subjects.
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Affiliation(s)
- Meera C Viswanathan
- Department of Biology, Molecular Biology Institute and Heart Institute, San Diego State University, San Diego, CA 92182-4614, USA.,Division of Cardiology, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Rick C Tham
- Department of Biology, Molecular Biology Institute and Heart Institute, San Diego State University, San Diego, CA 92182-4614, USA
| | - William A Kronert
- Department of Biology, Molecular Biology Institute and Heart Institute, San Diego State University, San Diego, CA 92182-4614, USA
| | - Floyd Sarsoza
- Department of Biology, Molecular Biology Institute and Heart Institute, San Diego State University, San Diego, CA 92182-4614, USA
| | - Adriana S Trujillo
- Department of Biology, Molecular Biology Institute and Heart Institute, San Diego State University, San Diego, CA 92182-4614, USA
| | - Anthony Cammarato
- Division of Cardiology, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Sanford I Bernstein
- Department of Biology, Molecular Biology Institute and Heart Institute, San Diego State University, San Diego, CA 92182-4614, USA
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15
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Viswanathan MC, Schmidt W, Rynkiewicz MJ, Agarwal K, Gao J, Katz J, Lehman W, Cammarato A. Distortion of the Actin A-Triad Results in Contractile Disinhibition and Cardiomyopathy. Cell Rep 2018; 20:2612-2625. [PMID: 28903042 PMCID: PMC5902318 DOI: 10.1016/j.celrep.2017.08.070] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2017] [Revised: 07/25/2017] [Accepted: 08/21/2017] [Indexed: 12/20/2022] Open
Abstract
Striated muscle contraction is regulated by the movement of tropomyosin over the thin filament surface, which blocks or exposes myosin binding sites on actin. Findings suggest that electrostatic contacts, particularly those between K326, K328, and R147 on actin and tropomyosin, establish an energetically favorable F-actin-tropomyosin configuration, with tropomyosin positioned in a location that impedes actomyosin associations and promotes relaxation. Here, we provide data that directly support a vital role for these actin residues, termed the A-triad, in tropomyosin positioning in intact functioning muscle. By examining the effects of an A295S α-cardiac actin hypertrophic cardiomyopathy-causing mutation, over a range of increasingly complex in silico, in vitro, and in vivo Drosophila muscle models, we propose that subtle A-triad-tropomyosin perturbation can destabilize thin filament regulation, which leads to hypercontractility and triggers disease. Our efforts increase understanding of basic thin filament biology and help unravel the mechanistic basis of a complex cardiac disorder.
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Affiliation(s)
- Meera C Viswanathan
- Division of Cardiology, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - William Schmidt
- Division of Cardiology, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Michael J Rynkiewicz
- Department of Physiology and Biophysics, Boston University School of Medicine, Boston, MA 02118, USA
| | - Karuna Agarwal
- Department of Mechanical Engineering, Johns Hopkins University, Baltimore, MD 21218, USA
| | - Jian Gao
- Department of Mechanical Engineering, Johns Hopkins University, Baltimore, MD 21218, USA
| | - Joseph Katz
- Department of Mechanical Engineering, Johns Hopkins University, Baltimore, MD 21218, USA
| | - William Lehman
- Department of Physiology and Biophysics, Boston University School of Medicine, Boston, MA 02118, USA
| | - Anthony Cammarato
- Division of Cardiology, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; Department of Physiology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
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16
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Limpitikul WB, Viswanathan MC, O'Rourke B, Yue DT, Cammarato A. Conservation of cardiac L-type Ca 2+ channels and their regulation in Drosophila: A novel genetically-pliable channelopathic model. J Mol Cell Cardiol 2018; 119:64-74. [PMID: 29684406 DOI: 10.1016/j.yjmcc.2018.04.010] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/10/2017] [Revised: 04/08/2018] [Accepted: 04/11/2018] [Indexed: 01/28/2023]
Abstract
Dysregulation of L-type Ca2+ channels (LTCCs) underlies numerous cardiac pathologies. Understanding their modulation with high fidelity relies on investigating LTCCs in their native environment with intact interacting proteins. Such studies benefit from genetic manipulation of endogenous channels in cardiomyocytes, which often proves cumbersome in mammalian models. Drosophila melanogaster, however, offers a potentially efficient alternative as it possesses a relatively simple heart, is genetically pliable, and expresses well-conserved genes. Fluorescence in situ hybridization confirmed an abundance of Ca-α1D and Ca-α1T mRNA in fly myocardium, which encode subunits that specify hetero-oligomeric channels homologous to mammalian LTCCs and T-type Ca2+ channels, respectively. Cardiac-specific knockdown of Ca-α1D via interfering RNA abolished cardiac contraction, suggesting Ca-α1D (i.e. A1D) represents the primary functioning Ca2+ channel in Drosophila hearts. Moreover, we successfully isolated viable single cardiomyocytes and recorded Ca2+ currents via patch clamping, a feat never before accomplished with the fly model. The profile of Ca2+ currents recorded in individual cells when Ca2+ channels were hypomorphic, absent, or under selective LTCC blockage by nifedipine, additionally confirmed the predominance of A1D current across all activation voltages. T-type current, activated at more negative voltages, was also detected. Lastly, A1D channels displayed Ca2+-dependent inactivation, a critical negative feedback mechanism of LTCCs, and the current through them was augmented by forskolin, an activator of the protein kinase A pathway. In sum, the Drosophila heart possesses a conserved compendium of Ca2+ channels, suggesting that the fly may serve as a robust and effective platform for studying cardiac channelopathies.
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Affiliation(s)
- Worawan B Limpitikul
- Calcium Signals Laboratory, Department of Biomedical Engineering, The Johns Hopkins University School of Medicine, Ross Research Building, 720 Rutland Avenue, Baltimore, MD 21205, United States
| | - Meera C Viswanathan
- Institute of CardioScience, Division of Cardiology, Department of Medicine, The Johns Hopkins University School of Medicine, Ross Research Building, 720 Rutland Avenue, Baltimore, MD 21205, United States
| | - Brian O'Rourke
- Institute of CardioScience, Division of Cardiology, Department of Medicine, The Johns Hopkins University School of Medicine, Ross Research Building, 720 Rutland Avenue, Baltimore, MD 21205, United States
| | - David T Yue
- Calcium Signals Laboratory, Department of Biomedical Engineering, The Johns Hopkins University School of Medicine, Ross Research Building, 720 Rutland Avenue, Baltimore, MD 21205, United States
| | - Anthony Cammarato
- Institute of CardioScience, Division of Cardiology, Department of Medicine, The Johns Hopkins University School of Medicine, Ross Research Building, 720 Rutland Avenue, Baltimore, MD 21205, United States; Department of Physiology, The Johns Hopkins University School of Medicine, Ross Research Building, 720 Rutland Avenue, Baltimore, MD 21205, United States.
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17
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Viswanathan MC, Schmidt W, Madan A, Sullivan LC, Newhard CS, Rynkiewicz MJ, Lehman W, Swank DM, Cammarato A. The ACTC M305L Hypertrophic Cardiomyopathy Mutation Results in Hypercontractility and Impaired Relaxation of Drosophila Muscles. Biophys J 2018. [DOI: 10.1016/j.bpj.2017.11.1776] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022] Open
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18
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Trujillo AS, Kronert WA, Bell K, Viswanathan MC, Melkani GC, Melkani A, Cammarato A, Swank DM, Bernstein SI. A R146N Hypertrophic Cardiomyopathy Myosin Mutation Disrupts Myosin Function, Myofibrillar Structure, and Cardiac Contraction in Drosophila. Biophys J 2017. [DOI: 10.1016/j.bpj.2016.11.1435] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
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19
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Madan A, Viswanathan MC, Lavorato M, Schmidt W, Ochala J, Cammarato A. ACTA1-Related Nemaline Myopathy Mutations Engender a Range of Structural and Functional Phenotypes in Drosophila Indirect Flight Muscles. Biophys J 2017. [DOI: 10.1016/j.bpj.2016.11.1010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
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20
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Blice-Baum AC, Viswanathan MC, Sang TK, Cammarato A. Cardiac-Specific Expression of VCP/TER94 RNAi or Disease Alleles Disrupts Drosophila Heart Structure and Impairs Function. Biophys J 2017. [DOI: 10.1016/j.bpj.2016.11.3014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022] Open
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21
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Blice-Baum AC, Zambon AC, Kaushik G, Viswanathan MC, Engler AJ, Bodmer R, Cammarato A. Modest overexpression of FOXO maintains cardiac proteostasis and ameliorates age-associated functional decline. Aging Cell 2017; 16:93-103. [PMID: 28090761 PMCID: PMC5242305 DOI: 10.1111/acel.12543] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/11/2016] [Indexed: 11/27/2022] Open
Abstract
Heart performance declines with age. Impaired protein quality control (PQC), due to reduced ubiquitin‐proteasome system (UPS) activity, autophagic function, and/or chaperone‐mediated protein refolding, contributes to cardiac deterioration. The transcription factor FOXO participates in regulating genes involved in PQC, senescence, and numerous other processes. Here, a comprehensive approach, involving molecular genetics, novel assays to probe insect cardiac physiology, and bioinformatics, was utilized to investigate the influence of heart‐restricted manipulation of dFOXO expression in the rapidly aging Drosophila melanogaster model. Modest dFOXO overexpression was cardioprotective, ameliorating nonpathological functional decline with age. This was accompanied by increased expression of genes associated predominantly with the UPS, relative to other PQC components, which was validated by a significant decrease in ubiquitinated proteins. RNAi knockdown of UPS candidates accordingly compromised myocardial physiology in young flies. Conversely, excessive dFOXO overexpression or suppression proved detrimental to heart function and/or organismal development. This study highlights D. melanogaster as a model of cardiac aging and FOXO as a tightly regulated mediator of proteostasis and heart performance over time.
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Affiliation(s)
- Anna C. Blice-Baum
- Division of Cardiology; Department of Medicine; Johns Hopkins University; Baltimore MD 21205 USA
| | - Alexander C. Zambon
- Department of Biopharmaceutical Sciences; Keck Graduate Institute; Claremont CA 91711 USA
- Sanford Burnham Prebys Medical Discovery Institute, Development, Aging and Regeneration Program; La Jolla CA 92037 USA
| | - Gaurav Kaushik
- Department of Bioengineering; University of California, San Diego; La Jolla CA 92093 USA
| | - Meera C. Viswanathan
- Division of Cardiology; Department of Medicine; Johns Hopkins University; Baltimore MD 21205 USA
| | - Adam J. Engler
- Department of Bioengineering; University of California, San Diego; La Jolla CA 92093 USA
| | - Rolf Bodmer
- Sanford Burnham Prebys Medical Discovery Institute, Development, Aging and Regeneration Program; La Jolla CA 92037 USA
| | - Anthony Cammarato
- Division of Cardiology; Department of Medicine; Johns Hopkins University; Baltimore MD 21205 USA
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22
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Viswanathan MC, Tham R, Kronert WA, Schmidt W, Sarsoza F, Trujillo AS, Bernstein SI, Cammarato A. Expression of Myosin Storage Myopathy Mutations in Drosophila Disrupts Muscle Function, Myofibrillar Structure and Causes Defects in Thick Filament Assembly. Biophys J 2017. [DOI: 10.1016/j.bpj.2016.11.660] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022] Open
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23
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Achal M, Trujillo AS, Melkani GC, Farman GP, Ocorr K, Viswanathan MC, Kaushik G, Newhard CS, Glasheen BM, Melkani A, Suggs JA, Moore JR, Swank DM, Bodmer R, Cammarato A, Bernstein SI. A Restrictive Cardiomyopathy Mutation in an Invariant Proline at the Myosin Head/Rod Junction Enhances Head Flexibility and Function, Yielding Muscle Defects in Drosophila. J Mol Biol 2016; 428:2446-2461. [PMID: 27107639 PMCID: PMC4884507 DOI: 10.1016/j.jmb.2016.04.021] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [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: 01/28/2016] [Revised: 04/12/2016] [Accepted: 04/13/2016] [Indexed: 11/27/2022]
Abstract
An "invariant proline" separates the myosin S1 head from its S2 tail and is proposed to be critical for orienting S1 during its interaction with actin, a process that leads to muscle contraction. Mutation of the invariant proline to leucine (P838L) caused dominant restrictive cardiomyopathy in a pediatric patient (Karam et al., Congenit. Heart Dis. 3:138-43, 2008). Here, we use Drosophila melanogaster to model this mutation and dissect its effects on the biochemical and biophysical properties of myosin, as well as on the structure and physiology of skeletal and cardiac muscles. P838L mutant myosin isolated from indirect flight muscles of transgenic Drosophila showed elevated ATPase and actin sliding velocity in vitro. Furthermore, the mutant heads exhibited increased rotational flexibility, and there was an increase in the average angle between the two heads. Indirect flight muscle myofibril assembly was minimally affected in mutant homozygotes, and isolated fibers displayed normal mechanical properties. However, myofibrils degraded during aging, correlating with reduced flight abilities. In contrast, hearts from homozygotes and heterozygotes showed normal morphology, myofibrillar arrays, and contractile parameters. When P838L was placed in trans to Mhc(5), an allele known to cause cardiac restriction in flies, it did not yield the constricted phenotype. Overall, our studies suggest that increased rotational flexibility of myosin S1 enhances myosin ATPase and actin sliding. Moreover, instability of P838L myofibrils leads to decreased function during aging of Drosophila skeletal muscle, but not cardiac muscle, despite the strong evolutionary conservation of the P838 residue.
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Affiliation(s)
- Madhulika Achal
- Biology Department, Molecular Biology Institute, Heart Institute, San Diego State University, San Diego, CA 92182-4614, USA
| | - Adriana S Trujillo
- Biology Department, Molecular Biology Institute, Heart Institute, San Diego State University, San Diego, CA 92182-4614, USA
| | - Girish C Melkani
- Biology Department, Molecular Biology Institute, Heart Institute, San Diego State University, San Diego, CA 92182-4614, USA
| | - Gerrie P Farman
- Department of Biological Sciences, University of Massachusetts, Lowell, MA 01854, USA
| | - Karen Ocorr
- Development, Aging and Regeneration Program, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA 92037, USA
| | - Meera C Viswanathan
- Department of Medicine, Division of Cardiology, Johns Hopkins University, Baltimore, MD 21205, USA
| | - Gaurav Kaushik
- Department of Bioengineering, University of California, San Diego, La Jolla, CA 92093, USA
| | - Christopher S Newhard
- Department of Biological Sciences and Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, NY 12180-3590, USA
| | - Bernadette M Glasheen
- Department of Biological Sciences and Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, NY 12180-3590, USA
| | - Anju Melkani
- Biology Department, Molecular Biology Institute, Heart Institute, San Diego State University, San Diego, CA 92182-4614, USA
| | - Jennifer A Suggs
- Biology Department, Molecular Biology Institute, Heart Institute, San Diego State University, San Diego, CA 92182-4614, USA
| | - Jeffrey R Moore
- Department of Biological Sciences, University of Massachusetts, Lowell, MA 01854, USA
| | - Douglas M Swank
- Department of Biological Sciences and Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, NY 12180-3590, USA
| | - Rolf Bodmer
- Development, Aging and Regeneration Program, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA 92037, USA
| | - Anthony Cammarato
- Department of Medicine, Division of Cardiology, Johns Hopkins University, Baltimore, MD 21205, USA
| | - Sanford I Bernstein
- Biology Department, Molecular Biology Institute, Heart Institute, San Diego State University, San Diego, CA 92182-4614, USA.
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24
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Viswanathan MC, Blice-Baum AC, Sang TK, Cammarato A. Cardiac-Restricted Expression of VCP/TER94 RNAi or Disease Alleles Perturbs Drosophila Heart Structure and Impairs Function. J Cardiovasc Dev Dis 2016; 3. [PMID: 27500162 PMCID: PMC4973812 DOI: 10.3390/jcdd3020019] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
Valosin-containing protein (VCP) is a highly conserved mechanoenzyme that helps maintain protein homeostasis in all cells and serves specialized functions in distinct cell types. In skeletal muscle, it is critical for myofibrillogenesis and atrophy. However, little is known about VCP’s role(s) in the heart. Its functional diversity is determined by differential binding of distinct cofactors/adapters, which is likely disrupted during disease. VCP mutations cause multisystem proteinopathy (MSP), a pleiotropic degenerative disorder that involves inclusion body myopathy. MSP patients display progressive muscle weakness. They also exhibit cardiomyopathy and die from cardiac and respiratory failure, which are consistent with critical myocardial roles for the enzyme. Nonetheless, efficient models to interrogate VCP in cardiac muscle remain underdeveloped and poorly studied. Here, we investigated the significance of VCP and mutant VCP in the Drosophila heart. Cardiac-restricted RNAi-mediated knockdown of TER94, the Drosophila VCP homolog, severely perturbed myofibrillar organization and heart function in adult flies. Furthermore, expression of MSP disease-causing alleles engendered cardiomyopathy in adults and structural defects in embryonic hearts. Drosophila may therefore serve as a valuable model for examining role(s) of VCP in cardiogenesis and for identifying novel heart-specific VCP interactions, which when disrupted via mutation, contribute to or elicit cardiac pathology.
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Affiliation(s)
- Meera C. Viswanathan
- Division of Cardiology, Department of Medicine, Johns Hopkins University, Ross 1050, 720 Rutland Avenue, Baltimore, MD 21205, USA; (M.C.V.); (A.C.B.-B.)
| | - Anna C. Blice-Baum
- Division of Cardiology, Department of Medicine, Johns Hopkins University, Ross 1050, 720 Rutland Avenue, Baltimore, MD 21205, USA; (M.C.V.); (A.C.B.-B.)
| | - Tzu-Kang Sang
- Institute of Biotechnology & Department of Life Science, National Tsing Hua University, Hsinchu City 30013, Taiwan;
| | - Anthony Cammarato
- Division of Cardiology, Department of Medicine, Johns Hopkins University, Ross 1050, 720 Rutland Avenue, Baltimore, MD 21205, USA; (M.C.V.); (A.C.B.-B.)
- Department of Physiology, Johns Hopkins University, Ross 1050, 720 Rutland Avenue, Baltimore, MD 21205, USA
- Correspondence: ; Tel.: +1-410-955-1807; Fax: +1-410-502-2558
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25
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Kooij V, Viswanathan MC, Lee DI, Rainer PP, Schmidt W, Kronert WA, Harding SE, Kass DA, Bernstein SI, Van Eyk JE, Cammarato A. Profilin modulates sarcomeric organization and mediates cardiomyocyte hypertrophy. Cardiovasc Res 2016; 110:238-48. [PMID: 26956799 PMCID: PMC4836629 DOI: 10.1093/cvr/cvw050] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/24/2015] [Accepted: 02/28/2016] [Indexed: 11/17/2022] Open
Abstract
Aims Heart failure is often preceded by cardiac hypertrophy, which is characterized by increased cell size, altered protein abundance, and actin cytoskeletal reorganization. Profilin is a well-conserved, ubiquitously expressed, multifunctional actin-binding protein, and its role in cardiomyocytes is largely unknown. Given its involvement in vascular hypertrophy, we aimed to test the hypothesis that profilin-1 is a key mediator of cardiomyocyte-specific hypertrophic remodelling. Methods and results Profilin-1 was elevated in multiple mouse models of hypertrophy, and a cardiomyocyte-specific increase of profilin in Drosophila resulted in significantly larger heart tube dimensions. Moreover, adenovirus-mediated overexpression of profilin-1 in neonatal rat ventricular myocytes (NRVMs) induced a hypertrophic response, measured by increased myocyte size and gene expression. Profilin-1 silencing suppressed the response in NRVMs stimulated with phenylephrine or endothelin-1. Mechanistically, we found that profilin-1 regulates hypertrophy, in part, through activation of the ERK1/2 signalling cascade. Confocal microscopy showed that profilin localized to the Z-line of Drosophila myofibrils under normal conditions and accumulated near the M-line when overexpressed. Elevated profilin levels resulted in elongated sarcomeres, myofibrillar disorganization, and sarcomeric disarray, which correlated with impaired muscle function. Conclusion Our results identify novel roles for profilin as an important mediator of cardiomyocyte hypertrophy. We show that overexpression of profilin is sufficient to induce cardiomyocyte hypertrophy and sarcomeric remodelling, and silencing of profilin attenuates the hypertrophic response.
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Affiliation(s)
- Viola Kooij
- Department of Medicine, Division of Cardiology, The Johns Hopkins University, Baltimore, MD, USA National Heart and Lung Institute, Imperial College London, 4th floor, ICTEM, Hammersmith Campus, Du Cane Road, London W12 0NN, UK
| | - Meera C Viswanathan
- Department of Medicine, Division of Cardiology, The Johns Hopkins University, Baltimore, MD, USA
| | - Dong I Lee
- Department of Medicine, Division of Cardiology, The Johns Hopkins University, Baltimore, MD, USA
| | - Peter P Rainer
- Department of Medicine, Division of Cardiology, The Johns Hopkins University, Baltimore, MD, USA Division of Cardiology, Medical University of Graz, Graz, Austria
| | - William Schmidt
- Department of Medicine, Division of Cardiology, The Johns Hopkins University, Baltimore, MD, USA
| | - William A Kronert
- Department of Biology, San Diego State University, San Diego, CA, USA
| | - Sian E Harding
- National Heart and Lung Institute, Imperial College London, 4th floor, ICTEM, Hammersmith Campus, Du Cane Road, London W12 0NN, UK
| | - David A Kass
- Department of Medicine, Division of Cardiology, The Johns Hopkins University, Baltimore, MD, USA
| | | | - Jennifer E Van Eyk
- Department of Medicine, Division of Cardiology, The Johns Hopkins University, Baltimore, MD, USA Advanced Clinical Biosystems Research Institute, Heart Institute and Department of Medicine, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - Anthony Cammarato
- Department of Medicine, Division of Cardiology, The Johns Hopkins University, Baltimore, MD, USA
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26
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Lavorato M, Schmidt W, Viswanathan MC, Ochala J, Franzini-Armstrong C, Cammarato A. The Actin F352S Nemaline Myopathy Mutation Disrupts Indirect Flight Muscle Structure and Function in Drosophila. Biophys J 2016. [DOI: 10.1016/j.bpj.2015.11.734] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
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27
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Limpitikul WB, Viswanathan MC, Cammarato A, Yue DT. Abstract 336: Conservation of Cardiac L-type Ca2+ Channels and Their Modulation in Drosophila: a Novel Genetically Pliable Channelopathic Model. Circ Res 2015. [DOI: 10.1161/res.117.suppl_1.336] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Misregulation of L-type Ca
2+
channels (LTCCs) underlies numerous cardiac pathologies. For example, heart failure features blunted protein kinase A (PKA) upregulation of the LTCCs. However, studying LTCC regulation in mammalian systems is challenging due to complex physiology and lack of genetic manipulability while recombinant channels expressed in heterologous systems, which lack key auxiliary elements, poorly represent the native context.
Drosophila
, however, has a simple heart with many conserved genes and is genetically pliable. Thus, we pinpointed the signature of Ca
2+
channels (CCs) in the fly cardiac tubes. First, RNAi-mediated selective knockdown of Dmca1D, homologous to the human LTCCs, abolished cardiac contraction (B, as compared to ctrl in A), establishing this channel isoform as the primary CC in fly hearts. Second, we successfully isolated viable single fly cardiomyocytes (C, inset) and recorded robust Ca
2+
currents using patch clamp electrophysiology (C), a feat never before accomplished for the fly cardiac system. Moreover, recording Ca
2+
currents in distinct hypomorphic CC lines, we confirmed the CC type in the fly heart. We also observed pharmacological responses of the CCs that were strikingly similar to those seen in humans. Current through Dmca1D is blocked by a dihydropiridine, nifedipine (C), and is readily upregulated by forskolin, a downstream activator of the PKA pathway (C). In all, we have established the existence of a conserved compendium of cardiac CCs in fly heart tubes, suggesting that
Drosophila
may serve as a robust and effective platform to study the pathophysiology of diseases involving cardiac CCs and to devise therapeutic strategies.
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Affiliation(s)
| | | | | | - David T Yue
- Johns Hopkins Univ Sch of Medicine, Baltimore, MD
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28
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Viswanathan MC, Blice-Baum AC, Schmidt W, Foster DB, Cammarato A. Pseudo-acetylation of K326 and K328 of actin disrupts Drosophila melanogaster indirect flight muscle structure and performance. Front Physiol 2015; 6:116. [PMID: 25972811 PMCID: PMC4412121 DOI: 10.3389/fphys.2015.00116] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2014] [Accepted: 03/26/2015] [Indexed: 01/13/2023] Open
Abstract
In striated muscle tropomyosin (Tm) extends along the length of F-actin-containing thin filaments. Its location governs access of myosin binding sites on actin and, hence, force production. Intermolecular electrostatic associations are believed to mediate critical interactions between the proteins. For example, actin residues K326, K328, and R147 were predicted to establish contacts with E181 of Tm. Moreover, K328 also potentially forms direct interactions with E286 of myosin when the motor is strongly bound. Recently, LC-MS/MS analysis of the cardiac acetyl-lysine proteome revealed K326 and K328 of actin were acetylated, a post-translational modification (PTM) that masks the residues' inherent positive charges. Here, we tested the hypothesis that by removing the vital actin charges at residues 326 and 328, the PTM would perturb Tm positioning and/or strong myosin binding as manifested by altered skeletal muscle function and structure in the Drosophila melanogaster model system. Transgenic flies were created that permit tissue-specific expression of K326Q, K328Q, or K326Q/K328Q acetyl-mimetic actin and of wild-type actin via the UAS-GAL4 bipartite expression system. Compared to wild-type actin, muscle-restricted expression of mutant actin had a dose-dependent effect on flight ability. Moreover, excessive K328Q and K326Q/K328Q actin overexpression induced indirect flight muscle degeneration, a phenotype consistent with hypercontraction observed in other Drosophila myofibrillar mutants. Based on F-actin-Tm and F-actin-Tm-myosin models and on our physiological data, we conclude that acetylating K326 and K328 of actin alters electrostatic associations with Tm and/or myosin and thereby augments contractile properties. Our findings highlight the utility of Drosophila as a model that permits efficient targeted design and assessment of molecular and tissue-specific responses to muscle protein modifications, in vivo.
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Affiliation(s)
- Meera C Viswanathan
- Division of Cardiology, Department of Medicine, Johns Hopkins University School of Medicine Baltimore, MD, USA
| | - Anna C Blice-Baum
- Division of Cardiology, Department of Medicine, Johns Hopkins University School of Medicine Baltimore, MD, USA
| | - William Schmidt
- Division of Cardiology, Department of Medicine, Johns Hopkins University School of Medicine Baltimore, MD, USA
| | - D Brian Foster
- Division of Cardiology, Department of Medicine, Johns Hopkins University School of Medicine Baltimore, MD, USA
| | - Anthony Cammarato
- Division of Cardiology, Department of Medicine, Johns Hopkins University School of Medicine Baltimore, MD, USA
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29
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Viswanathan MC, Glasheen BM, Bell K, Swank DM, Cammarato A. The ACTC A295S Mutation Increases Heart and Skeletal Muscle Contractile Activity in Drosophila Models of Hypertrophic Cardiomyopathy. Biophys J 2014. [DOI: 10.1016/j.bpj.2013.11.4249] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
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30
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Blice-Baum A, Kaushik G, Viswanathan MC, Bodmer R, Engler AJ, Cammarato A. Cardiac-Specific Overexpression of FOXO Affords Protection Against Age-Associated Decline in Cardiac Performance in the Drosophila Model. Biophys J 2014. [DOI: 10.1016/j.bpj.2013.11.4260] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
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