1
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Guo Y, Yan J, Goult BT. Mechanotransduction through protein stretching. Curr Opin Cell Biol 2024; 87:102327. [PMID: 38301379 DOI: 10.1016/j.ceb.2024.102327] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2023] [Revised: 01/08/2024] [Accepted: 01/08/2024] [Indexed: 02/03/2024]
Abstract
Cells sense and respond to subtle changes in their physicality, and via a myriad of different mechanosensitive processes, convert these physical cues into chemical and biochemical signals. This process, called mechanotransduction, is possible due to a highly sophisticated machinery within cells. One mechanism by which this can occur is via the stretching of mechanosensitive proteins. Stretching proteins that contain force-dependent regions results in altered geometry and dimensions of the connections, as well as differential spatial organization of signals bound to the stretched protein. The purpose of this mini-review is to discuss some of the intense recent activity in this area of mechanobiology that strives to understand how protein stretching can influence signaling outputs and cellular responses.
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Affiliation(s)
- Yanyu Guo
- Department of Physics, Mechanobiology Institute, National University of Singapore 117542, Singapore
| | - Jie Yan
- Department of Physics, Mechanobiology Institute, National University of Singapore 117542, Singapore.
| | - Benjamin T Goult
- School of Biosciences, University of Kent, Canterbury, Kent, CT2 7NJ, UK; Department of Biochemistry, Cell & Systems Biology, Institute of Systems, Molecular & Integrative Biology, University of Liverpool, Crown Street, Liverpool L69 7ZB, UK.
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2
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Szwec S, Kapłucha Z, Chamberlain JS, Konieczny P. Dystrophin- and Utrophin-Based Therapeutic Approaches for Treatment of Duchenne Muscular Dystrophy: A Comparative Review. BioDrugs 2024; 38:95-119. [PMID: 37917377 PMCID: PMC10789850 DOI: 10.1007/s40259-023-00632-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/10/2023] [Indexed: 11/04/2023]
Abstract
Duchenne muscular dystrophy is a devastating disease that leads to progressive muscle loss and premature death. While medical management focuses mostly on symptomatic treatment, decades of research have resulted in first therapeutics able to restore the affected reading frame of dystrophin transcripts or induce synthesis of a truncated dystrophin protein from a vector, with other strategies based on gene therapy and cell signaling in preclinical or clinical development. Nevertheless, recent reports show that potentially therapeutic dystrophins can be immunogenic in patients. This raises the question of whether a dystrophin paralog, utrophin, could be a more suitable therapeutic protein. Here, we compare dystrophin and utrophin amino acid sequences and structures, combining published data with our extended in silico analyses. We then discuss these results in the context of therapeutic approaches for Duchenne muscular dystrophy. Specifically, we focus on strategies based on delivery of micro-dystrophin and micro-utrophin genes with recombinant adeno-associated viral vectors, exon skipping of the mutated dystrophin pre-mRNAs, reading through termination codons with small molecules that mask premature stop codons, dystrophin gene repair by clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated protein 9 (CRISPR/Cas9)-mediated genetic engineering, and increasing utrophin levels. Our analyses highlight the importance of various dystrophin and utrophin domains in Duchenne muscular dystrophy treatment, providing insights into designing novel therapeutic compounds with improved efficacy and decreased immunoreactivity. While the necessary actin and β-dystroglycan binding sites are present in both proteins, important functional distinctions can be identified in these domains and some other parts of truncated dystrophins might need redesigning due to their potentially immunogenic qualities. Alternatively, therapies based on utrophins might provide a safer and more effective approach.
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Affiliation(s)
- Sylwia Szwec
- Institute of Human Biology and Evolution, Faculty of Biology, Adam Mickiewicz University, ul. Uniwersytetu Poznańskiego 6, 61-614, Poznań, Poland
| | - Zuzanna Kapłucha
- Institute of Human Biology and Evolution, Faculty of Biology, Adam Mickiewicz University, ul. Uniwersytetu Poznańskiego 6, 61-614, Poznań, Poland
| | - Jeffrey S Chamberlain
- Department of Neurology, University of Washington School of Medicine, Seattle, WA, 98109-8055, USA
- Senator Paul D. Wellstone Muscular Dystrophy Specialized Research Center, University of Washington School of Medicine, Seattle, WA, 98109-8055, USA
- Department of Biochemistry, University of Washington School of Medicine, Seattle, WA, 98109-8055, USA
- Department of Medicine, University of Washington School of Medicine, Seattle, WA, 98109-8055, USA
| | - Patryk Konieczny
- Institute of Human Biology and Evolution, Faculty of Biology, Adam Mickiewicz University, ul. Uniwersytetu Poznańskiego 6, 61-614, Poznań, Poland.
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3
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Mirouse V. Evolution and developmental functions of the dystrophin-associated protein complex: beyond the idea of a muscle-specific cell adhesion complex. Front Cell Dev Biol 2023; 11:1182524. [PMID: 37384252 PMCID: PMC10293626 DOI: 10.3389/fcell.2023.1182524] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2023] [Accepted: 05/30/2023] [Indexed: 06/30/2023] Open
Abstract
The Dystrophin-Associated Protein Complex (DAPC) is a well-defined and evolutionarily conserved complex in animals. DAPC interacts with the F-actin cytoskeleton via dystrophin, and with the extracellular matrix via the membrane protein dystroglycan. Probably for historical reasons that have linked its discovery to muscular dystrophies, DAPC function is often described as limited to muscle integrity maintenance by providing mechanical robustness, which implies strong cell-extracellular matrix adhesion properties. In this review, phylogenetic and functional data from different vertebrate and invertebrate models will be analyzed and compared to explore the molecular and cellular functions of DAPC, with a specific focus on dystrophin. These data reveals that the evolution paths of DAPC and muscle cells are not intrinsically linked and that many features of dystrophin protein domains have not been identified yet. DAPC adhesive properties also are discussed by reviewing the available evidence of common key features of adhesion complexes, such as complex clustering, force transmission, mechanosensitivity and mechanotransduction. Finally, the review highlights DAPC developmental roles in tissue morphogenesis and basement membrane (BM) assembly that may indicate adhesion-independent functions.
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4
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Evaluation of the dystrophin carboxy-terminal domain for micro-dystrophin gene therapy in cardiac and skeletal muscles in the DMD mdx rat model. Gene Ther 2022; 29:520-535. [PMID: 35105949 DOI: 10.1038/s41434-022-00317-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2021] [Revised: 12/09/2021] [Accepted: 01/13/2022] [Indexed: 01/02/2023]
Abstract
Duchenne muscular dystrophy (DMD) is a muscle wasting disorder caused by mutations in the gene encoding dystrophin. Gene therapy using micro-dystrophin (MD) transgenes and recombinant adeno-associated virus (rAAV) vectors hold great promise. To overcome the limited packaging capacity of rAAV vectors, most MD do not include dystrophin carboxy-terminal (CT) domain. Yet, the CT domain is known to recruit α1- and β1-syntrophins and α-dystrobrevin, a part of the dystrophin-associated protein complex (DAPC), which is a signaling and structural mediator of muscle cells. In this study, we explored the impact of inclusion of the dystrophin CT domain on ΔR4-23/ΔCT MD (MD1), in DMDmdx rats, which allows for relevant evaluations at muscular and cardiac levels. We showed by LC-MS/MS that MD1 expression is sufficient to restore the interactions at a physiological level of most DAPC partners in skeletal and cardiac muscles, and that inclusion of the CT domain increases the recruitment of some DAPC partners at supra-physiological levels. In parallel, we demonstrated that inclusion of the CT domain does not improve MD1 therapeutic efficacy on DMD muscle and cardiac pathologies. Our work highlights new evidences of the therapeutic potential of MD1 and strengthens the relevance of this candidate for gene therapy of DMD.
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5
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Wang H, Marrosu E, Brayson D, Wasala NB, Johnson EK, Scott CS, Yue Y, Hau KL, Trask AJ, Froehner SC, Adams ME, Zhang L, Duan D, Montanaro F. Proteomic analysis identifies key differences in the cardiac interactomes of dystrophin and micro-dystrophin. Hum Mol Genet 2021; 30:1321-1336. [PMID: 33949649 PMCID: PMC8255133 DOI: 10.1093/hmg/ddab133] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2021] [Revised: 04/26/2021] [Accepted: 04/29/2021] [Indexed: 01/16/2023] Open
Abstract
ΔR4-R23/ΔCT micro-dystrophin (μDys) is a miniaturized version of dystrophin currently evaluated in a Duchenne muscular dystrophy (DMD) gene therapy trial to treat skeletal and cardiac muscle disease. In pre-clinical studies, μDys efficiently rescues cardiac histopathology, but only partially normalizes cardiac function. To gain insights into factors that may impact the cardiac therapeutic efficacy of μDys, we compared by mass spectrometry the composition of purified dystrophin and μDys protein complexes in the mouse heart. We report that compared to dystrophin, μDys has altered associations with α1- and β2-syntrophins, as well as cavins, a group of caveolae-associated signaling proteins. In particular, we found that membrane localization of cavin-1 and cavin-4 in cardiomyocytes requires dystrophin and is profoundly disrupted in the heart of mdx5cv mice, a model of DMD. Following cardiac stress/damage, membrane-associated cavin-4 recruits the signaling molecule ERK to caveolae, which activates key cardio-protective responses. Evaluation of ERK signaling revealed a profound inhibition, below physiological baseline, in the mdx5cv mouse heart. Expression of μDys in mdx5cv mice prevented the development of cardiac histopathology but did not rescue membrane localization of cavins nor did it normalize ERK signaling. Our study provides the first comparative analysis of purified protein complexes assembled in vivo by full-length dystrophin and a therapeutic micro-dystrophin construct. This has revealed disruptions in cavins and ERK signaling that may contribute to DMD cardiomyopathy. This new knowledge is important for ongoing efforts to prevent and treat heart disease in DMD patients.
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Affiliation(s)
- Hong Wang
- Center for Gene Therapy, The Research Institute at Nationwide Children's Hospital, Columbus OH 43205, USA.,Department of Pediatric Cardiology, China Medical University, Liaoning 110004, China
| | - Elena Marrosu
- Developmental Neuroscience Research and Teaching Department, Dubowitz Neuromuscular Centre, Molecular Neurosciences Section, UCL Great Ormond Street Institute of Child Health, London WC1N 1EH, UK.,NIHR Great Ormond Street Hospital Biomedical Research Centre, London WC1N 1EH, UK
| | - Daniel Brayson
- Developmental Neuroscience Research and Teaching Department, Dubowitz Neuromuscular Centre, Molecular Neurosciences Section, UCL Great Ormond Street Institute of Child Health, London WC1N 1EH, UK.,NIHR Great Ormond Street Hospital Biomedical Research Centre, London WC1N 1EH, UK
| | - Nalinda B Wasala
- Department of Molecular Microbiology and Immunology, School of Medicine, University of Missouri, Columbia, MO 65211, USA
| | - Eric K Johnson
- Center for Gene Therapy, The Research Institute at Nationwide Children's Hospital, Columbus OH 43205, USA
| | - Charlotte S Scott
- Developmental Neuroscience Research and Teaching Department, Dubowitz Neuromuscular Centre, Molecular Neurosciences Section, UCL Great Ormond Street Institute of Child Health, London WC1N 1EH, UK.,NIHR Great Ormond Street Hospital Biomedical Research Centre, London WC1N 1EH, UK
| | - Yongping Yue
- Department of Molecular Microbiology and Immunology, School of Medicine, University of Missouri, Columbia, MO 65211, USA
| | - Kwan-Leong Hau
- Developmental Neuroscience Research and Teaching Department, Dubowitz Neuromuscular Centre, Molecular Neurosciences Section, UCL Great Ormond Street Institute of Child Health, London WC1N 1EH, UK.,NIHR Great Ormond Street Hospital Biomedical Research Centre, London WC1N 1EH, UK
| | - Aaron J Trask
- Center for Cardiovascular Research, The Research Institute at Nationwide Children's Hospital, Columbus, OH 43205, USA.,Department of Pediatrics, The Ohio State University College of Medicine, Columbus, OH 43205, USA
| | - Stan C Froehner
- Department of Physiology and Biophysics, University of Washington, Seattle, WA 98195, USA
| | - Marvin E Adams
- Department of Physiology and Biophysics, University of Washington, Seattle, WA 98195, USA
| | - Liwen Zhang
- Mass Spectrometry and Proteomics Facility, Campus Chemical Instrument Center, The Ohio State University, Columbus, OH 43210, USA
| | - Dongsheng Duan
- Department of Molecular Microbiology and Immunology, School of Medicine, University of Missouri, Columbia, MO 65211, USA.,Department of Neurology, School of Medicine, College of Veterinary Medicine, University of Missouri, Columbia, MO 65211, USA.,Department of Bioengineering, College of Veterinary Medicine, University of Missouri, Columbia, MO 65211, USA.,Department of Biomedical Sciences, College of Veterinary Medicine, University of Missouri, Columbia, MO 65211, USA.,Department of Biomedical, Biological and Chemical Engineering, College of Engineering, University of Missouri, Columbia, MO 65211, USA
| | - Federica Montanaro
- Center for Gene Therapy, The Research Institute at Nationwide Children's Hospital, Columbus OH 43205, USA.,Developmental Neuroscience Research and Teaching Department, Dubowitz Neuromuscular Centre, Molecular Neurosciences Section, UCL Great Ormond Street Institute of Child Health, London WC1N 1EH, UK.,NIHR Great Ormond Street Hospital Biomedical Research Centre, London WC1N 1EH, UK
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6
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Swiderski K, Brock CJ, Trieu J, Chee A, Thakur SS, Baum DM, Gregorevic P, Murphy KT, Lynch GS. Phosphorylation of ERK and dystrophin S3059 protects against inflammation-associated C2C12 myotube atrophy. Am J Physiol Cell Physiol 2021; 320:C956-C965. [PMID: 33729835 DOI: 10.1152/ajpcell.00513.2020] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The dystrophin-glycoprotein complex (DGC) is a multiprotein structure required to maintain muscle fiber membrane integrity, transmit force by linking the actin cytoskeleton with the extracellular matrix, and maintain muscle homeostasis. Membrane localization of dystrophin is perturbed in muscles wasting as a consequence of cancer cachexia, tenotomy, and advanced aging, which are all associated with low level, chronic inflammation. Strategies to preserve dystrophin expression at the sarcolemma might therefore combat muscle wasting. Phosphorylation of dystrophin serine 3059 (S3059) enhances the interaction between dystrophin and β-dystroglycan. To test the contribution of amino acid phosphorylation to muscle fiber size changes, dystrophin constructs with phospho-null and phosphomimetic mutations were transfected into C2C12 muscle cells or AAV-293 cells in the presence or absence of kinase inhibitors/activators to assess effects on myotube diameter and protein function. Overexpression of a dystrophin construct with a phospho-null mutation at S3059 in vitro reduced myotube size in healthy C2C12 cells. Conversely overexpression of a phosphomimetic mutation at S3059 attenuated inflammation-induced myotube atrophy. Increased ERK activation by addition of phorbol myristate acetate (PMA) also reduced inflammation-associated myotube atrophy and increased the interaction between dystrophin and β-dystroglycan. These findings demonstrate a link between increased ERK activation, dystrophin S3059 phosphorylation, stabilization of the DGC, and the regulation of muscle fiber size. Interventions that increase dystrophin S3059 phosphorylation to promote stronger binding of dystrophin to β-dystroglycan may have therapeutic potential for attenuation of inflammation-associated muscle wasting.
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Affiliation(s)
- Kristy Swiderski
- Centre for Muscle Research, Department of Anatomy and Physiology, The University of Melbourne, Melbourne, Victoria, Australia
| | - Christopher J Brock
- Centre for Muscle Research, Department of Anatomy and Physiology, The University of Melbourne, Melbourne, Victoria, Australia
| | - Jennifer Trieu
- Centre for Muscle Research, Department of Anatomy and Physiology, The University of Melbourne, Melbourne, Victoria, Australia
| | - Annabel Chee
- Centre for Muscle Research, Department of Anatomy and Physiology, The University of Melbourne, Melbourne, Victoria, Australia
| | - Savant S Thakur
- Centre for Muscle Research, Department of Anatomy and Physiology, The University of Melbourne, Melbourne, Victoria, Australia
| | - Dale M Baum
- Centre for Muscle Research, Department of Anatomy and Physiology, The University of Melbourne, Melbourne, Victoria, Australia
| | - Paul Gregorevic
- Centre for Muscle Research, Department of Anatomy and Physiology, The University of Melbourne, Melbourne, Victoria, Australia
| | - Kate T Murphy
- Centre for Muscle Research, Department of Anatomy and Physiology, The University of Melbourne, Melbourne, Victoria, Australia
| | - Gordon S Lynch
- Centre for Muscle Research, Department of Anatomy and Physiology, The University of Melbourne, Melbourne, Victoria, Australia
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Stephenson AA, Flanigan KM. Gene editing and modulation for Duchenne muscular dystrophy. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2021; 182:225-255. [PMID: 34175043 DOI: 10.1016/bs.pmbts.2021.01.029] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
Duchenne muscular dystrophy (DMD) is a progressive muscle disease caused by loss of dystrophin protein, encoded by the DMD gene. DMD manifests early in childhood as difficulty walking, progresses to loss of ambulation by the teens, and leads to death in early adulthood. Adeno-associated virus-vectorized gene therapies to restore dystrophin protein expression using gene replacement or antisense oligonucleotide-mediated pre-mRNA splicing modulation have emerged, making great strides in uncovering barriers to gene therapies for DMD and other genetic diseases. While this first-generation of DMD therapies are being evaluated in ongoing clinical trials, uncertainties regarding durability and therapeutic efficacy prompted the development of new experimental therapies for DMD that take advantage of somatic cell gene editing. These experimental therapies continue to advance toward clinic trials, but questions remain unanswered regarding safety and translatable efficacy. Here we review the advancements toward treatment of DMD using gene editing and modulation therapies, with an emphasis on those nearest to clinical applications.
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Affiliation(s)
- Anthony A Stephenson
- Center for Gene Therapy, Abigail Wexner Research Institute, Nationwide Children's Hospital, Columbus, OH, United States
| | - Kevin M Flanigan
- Center for Gene Therapy, Abigail Wexner Research Institute, Nationwide Children's Hospital, Columbus, OH, United States; Department of Pediatrics, College of Medicine, The Ohio State University, Columbus, OH, United States; Department of Neurology, College of Medicine, The Ohio State University, Columbus, OH, United States.
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8
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Kim MJ, Whitehead NP, Bible KL, Adams ME, Froehner SC. Mice lacking α-, β1- and β2-syntrophins exhibit diminished function and reduced dystrophin expression in both cardiac and skeletal muscle. Hum Mol Genet 2019; 28:386-395. [PMID: 30256963 DOI: 10.1093/hmg/ddy341] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2018] [Accepted: 09/21/2018] [Indexed: 01/16/2023] Open
Abstract
Syntrophins are a family of modular adaptor proteins that are part of the dystrophin protein complex, where they recruit and anchor a variety of signaling proteins. Previously we generated mice lacking α- and/or β2-syntrophin but showed that in the absence of one isoform, other syntrophin isoforms can partially compensate. Therefore, in the current study, we generated mice that lacked α, β1 and β2-syntrophins [triple syntrophin knockout (tKO) mice] and assessed skeletal and cardiac muscle function. The tKO mice showed a profound reduction in voluntary wheel running activity at both 6 and 12 months of age. Function of the tibialis anterior was assessed in situ and we found that the specific force of tKO muscle was decreased by 20-25% compared with wild-type mice. This decrease was accompanied by a shift in fiber-type composition from fast 2B to more oxidative fast 2A fibers. Using echocardiography to measure cardiac function, it was revealed that tKO hearts had left ventricular cardiac dysfunction and were hypertrophic, with a thicker left ventricular posterior wall. Interestingly, we also found that membrane-localized dystrophin expression was lower in both skeletal and cardiac muscles of tKO mice. Since dystrophin mRNA levels were not different in tKO, this finding suggests that syntrophins may regulate dystrophin trafficking to, or stabilization at, the sarcolemma. These results show that the loss of all three major muscle syntrophins has a profound effect on exercise performance, and skeletal and cardiac muscle dysfunction contributes to this deficiency.
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Affiliation(s)
- Min Jeong Kim
- Department of Physiology and Biophysics, University of Washington, Seattle, WA, USA
| | - Nicholas P Whitehead
- Department of Physiology and Biophysics, University of Washington, Seattle, WA, USA
| | - Kenneth L Bible
- Department of Physiology and Biophysics, University of Washington, Seattle, WA, USA
| | - Marvin E Adams
- Department of Physiology and Biophysics, University of Washington, Seattle, WA, USA
| | - Stanley C Froehner
- Department of Physiology and Biophysics, University of Washington, Seattle, WA, USA
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9
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Adams ME, Odom GL, Kim MJ, Chamberlain JS, Froehner SC. Syntrophin binds directly to multiple spectrin-like repeats in dystrophin and mediates binding of nNOS to repeats 16-17. Hum Mol Genet 2019; 27:2978-2985. [PMID: 29790927 DOI: 10.1093/hmg/ddy197] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2018] [Accepted: 05/14/2018] [Indexed: 11/12/2022] Open
Abstract
Mutation of the gene encoding dystrophin leads to Duchenne and Becker muscular dystrophy (DMD and BMD). Currently, dystrophin is thought to function primarily as a structural protein, connecting the muscle cell actin cytoskeleton to the extra-cellular matrix. In addition to this structural role, dystrophin also plays an important role as a scaffold that organizes an array of signaling proteins including sodium, potassium, and calcium channels, kinases, and nitric oxide synthase (nNOS). Many of these signaling proteins are linked to dystrophin via syntrophin, an adapter protein that is known to bind directly to two sites in the carboxyl terminal region of dystrophin. A search of the dystrophin sequence revealed three additional potential syntrophin binding sites (SBSs) within the spectrin-like repeat (SLR) region of dystrophin. Binding assays revealed that the site at SLR 17 bound specifically to the α isoform of syntrophin while the site at SLR 22 bound specifically to the β-syntrophins. The SLR 17 α-SBS contained the core sequence known to be required for nNOS-dystrophin interaction. In vitro and in vivo assays indicate that α-syntrophin facilitates the nNOS-dystrophin interaction at this site rather than nNOS binding directly to dystrophin as previously reported. The identification of multiple SBSs within the SLR region of dystrophin demonstrates that this region functions as a signaling scaffold. The signaling role of the SLR region of dystrophin will need to be considered for effective gene replacement or exon skipping based DMD/BMD therapies.
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Affiliation(s)
- Marvin E Adams
- Department of Physiology and Biophysics, University of Washington, Seattle, WA 98195-7290, USA
| | - Guy L Odom
- Department of Neurology, University of Washington, Seattle, WA 98195-7290, USA.,Senator Paul D. Wellstone Muscular Dystrophy Cooperative Research Center, University of Washington, Seattle, WA 98195-7720, USA
| | - Min Jeong Kim
- Department of Physiology and Biophysics, University of Washington, Seattle, WA 98195-7290, USA
| | - Jeffrey S Chamberlain
- Department of Neurology, University of Washington, Seattle, WA 98195-7290, USA.,Department of Biochemistry, University of Washington, Seattle, WA 98195-7290, USA.,Senator Paul D. Wellstone Muscular Dystrophy Cooperative Research Center, University of Washington, Seattle, WA 98195-7720, USA
| | - Stanley C Froehner
- Department of Physiology and Biophysics, University of Washington, Seattle, WA 98195-7290, USA
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10
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Bhat SS, Ali R, Khanday FA. Syntrophins entangled in cytoskeletal meshwork: Helping to hold it all together. Cell Prolif 2019; 52:e12562. [PMID: 30515904 PMCID: PMC6496184 DOI: 10.1111/cpr.12562] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2018] [Revised: 10/23/2018] [Accepted: 11/08/2018] [Indexed: 01/10/2023] Open
Abstract
Syntrophins are a family of 59 kDa peripheral membrane-associated adapter proteins, containing multiple protein-protein and protein-lipid interaction domains. The syntrophin family consists of five isoforms that exhibit specific tissue distribution, distinct sub-cellular localization and unique expression patterns implying their diverse functional roles. These syntrophin isoforms form multiple functional protein complexes and ensure proper localization of signalling proteins and their binding partners to specific membrane domains and provide appropriate spatiotemporal regulation of signalling pathways. Syntrophins consist of two PH domains, a PDZ domain and a conserved SU domain. The PH1 domain is split by the PDZ domain. The PH2 and the SU domain are involved in the interaction between syntrophin and the dystrophin-glycoprotein complex (DGC). Syntrophins recruit various signalling proteins to DGC and link extracellular matrix to internal signalling apparatus via DGC. The different domains of the syntrophin isoforms are responsible for modulation of cytoskeleton. Syntrophins associate with cytoskeletal proteins and lead to various cellular responses by modulating the cytoskeleton. Syntrophins are involved in many physiological processes which involve cytoskeletal reorganization like insulin secretion, blood pressure regulation, myogenesis, cell migration, formation and retraction of focal adhesions. Syntrophins have been implicated in various pathologies like Alzheimer's disease, muscular dystrophy, cancer. Their role in cytoskeletal organization and modulation makes them perfect candidates for further studies in various cancers and other ailments that involve cytoskeletal modulation. The role of syntrophins in cytoskeletal organization and modulation has not yet been comprehensively reviewed till now. This review focuses on syntrophins and highlights their role in cytoskeletal organization, modulation and dynamics via its involvement in different cell signalling networks.
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Affiliation(s)
- Sahar S. Bhat
- Division of BiotechnologySher‐e‐Kashmir University of Agricultural Sciences and Technology of KashmirSrinagarIndia
| | - Roshia Ali
- Department of BiotechnologyUniversity of KashmirSrinagarIndia
- Department of BiochemistryUniversity of KashmirSrinagarIndia
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11
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Balke JE, Zhang L, Percival JM. Neuronal nitric oxide synthase (nNOS) splice variant function: Insights into nitric oxide signaling from skeletal muscle. Nitric Oxide 2018; 82:35-47. [PMID: 30503614 DOI: 10.1016/j.niox.2018.11.004] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2018] [Revised: 11/19/2018] [Accepted: 11/20/2018] [Indexed: 02/07/2023]
Abstract
Defects in neuronal nitric oxide synthase (nNOS) splice variant localization and signaling in skeletal muscle are a firmly established pathogenic characteristic of many neuromuscular diseases, including Duchenne and Becker muscular dystrophy (DMD and BMD, respectively). Therefore, substantial efforts have been made to understand and therapeutically target skeletal muscle nNOS isoform signaling. The purpose of this review is to summarize recent salient advances in understanding of the regulation, targeting, and function of nNOSμ and nNOSβ splice variants in normal and dystrophic skeletal muscle, primarily using findings from mouse models. The first focus of this review is how the differential targeting of nNOS splice variants creates spatially and functionally distinct nitric oxide (NO) signaling compartments at the sarcolemma, Golgi complex, and cytoplasm. Particular attention is given to the functions of sarcolemmal nNOSμ and limitations of current nNOS knockout models. The second major focus is to review current understanding of cGMP-mediated nNOS signaling in skeletal muscle and its emergence as a therapeutic target in DMD and BMD. Accordingly, we address the preclinical and clinical successes and setbacks with the testing of phosphodiesterase 5 inhibitors to redress nNOS signaling defects in DMD and BMD. In summary, this review of nNOS function in normal and dystrophic muscle aims to advance understanding how the messenger NO is harnessed for cellular signaling from a skeletal muscle perspective.
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Affiliation(s)
- Jordan E Balke
- Department of Molecular and Cellular Pharmacology, University of Miami Miller School of Medicine Miami, Florida, 33101, USA
| | - Ling Zhang
- Department of Molecular and Cellular Pharmacology, University of Miami Miller School of Medicine Miami, Florida, 33101, USA
| | - Justin M Percival
- Department of Molecular and Cellular Pharmacology, University of Miami Miller School of Medicine Miami, Florida, 33101, USA.
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12
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Li T, Zhang ZJ, Ma X, Lv X, Xiao H, Guo QN, Liu HY, Wang HD, Wu D, Lou GY, Wang X, Zhang CY, Liao SX. Prenatal diagnosis for a Chinese family with a de novo DMD gene mutation: A case report. Medicine (Baltimore) 2017; 96:e8814. [PMID: 29390271 PMCID: PMC5815683 DOI: 10.1097/md.0000000000008814] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/24/2017] [Revised: 10/28/2017] [Accepted: 10/31/2017] [Indexed: 12/15/2022] Open
Abstract
BACKGROUND Patients with Duchenne muscular dystrophy (DMD) usually have severe and fatal symptoms. At present, there is no effective treatment for DMD, thus it is very important to avoid the birth of children with DMD by effective prenatal diagnosis. We identified a de novo DMD gene mutation in a Chinese family, and make a prenatal diagnosis. METHODS First, multiplex ligation-dependent probe amplification (MLPA) was applied to analyze DMD gene exon deletion/duplication in all family members. The coding sequences of 79 exons in DMD gene were analyzed by Sanger sequencing in the patient; and then according to DMD gene exon mutation in the patient, DMD gene sequencing was performed in the family members. On the basis of results above, the pathogenic mutation in DMD gene was identified. RESULTS MLPA showed no DMD gene exon deletion/duplication in all family members. Sanger sequencing revealed c.2767_2767delT [p.Ser923LeufsX26] mutation in DMD gene of the patient. Heterozygous deletion mutation (T/-) at this locus was observed in the pregnant woman and her mother and younger sister. The analyses of amniotic fluid samples indicated negative Y chromosome sex-determining gene, no DMD gene exon deletion/duplication, no mutations at c.2767 locus, and the inherited maternal X chromosome different from that of the patient. CONCLUSION The pathogenic mutation in DMD gene, c.2767_2767delT [p.Ser923LeufsX26], identified in this family is a de novo mutation. On the basis of specific conditions, it is necessary to select suitable methods to make prenatal diagnosis more effective, accurate, and economic.
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Affiliation(s)
- Tao Li
- Institute of Medical Genetics (Prenatal Diagnosis Center), People's Hospital of Zhengzhou University, Henan Provincial People's Hospital
| | - Zhao-jing Zhang
- Department of Medical Genetics and Cell Biology, College of Basic Medical Science, Zhengzhou University
| | - Xin Ma
- Department of Stomatology
| | - Xue Lv
- Department of Health Management, People's Hospital of Zhengzhou University, Henan Provincial People's Hospital, Zhengzhou, China
| | - Hai Xiao
- Institute of Medical Genetics (Prenatal Diagnosis Center), People's Hospital of Zhengzhou University, Henan Provincial People's Hospital
| | - Qian-nan Guo
- Institute of Medical Genetics (Prenatal Diagnosis Center), People's Hospital of Zhengzhou University, Henan Provincial People's Hospital
| | - Hong-yan Liu
- Institute of Medical Genetics (Prenatal Diagnosis Center), People's Hospital of Zhengzhou University, Henan Provincial People's Hospital
| | - Hong-dan Wang
- Institute of Medical Genetics (Prenatal Diagnosis Center), People's Hospital of Zhengzhou University, Henan Provincial People's Hospital
| | - Dong Wu
- Institute of Medical Genetics (Prenatal Diagnosis Center), People's Hospital of Zhengzhou University, Henan Provincial People's Hospital
| | - Gui-yu Lou
- Institute of Medical Genetics (Prenatal Diagnosis Center), People's Hospital of Zhengzhou University, Henan Provincial People's Hospital
| | - Xin Wang
- Institute of Medical Genetics (Prenatal Diagnosis Center), People's Hospital of Zhengzhou University, Henan Provincial People's Hospital
| | - Chao-yang Zhang
- Institute of Medical Genetics (Prenatal Diagnosis Center), People's Hospital of Zhengzhou University, Henan Provincial People's Hospital
| | - Shi-xiu Liao
- Institute of Medical Genetics (Prenatal Diagnosis Center), People's Hospital of Zhengzhou University, Henan Provincial People's Hospital
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13
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Gawor M, Prószyński TJ. The molecular cross talk of the dystrophin-glycoprotein complex. Ann N Y Acad Sci 2017; 1412:62-72. [DOI: 10.1111/nyas.13500] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2017] [Revised: 08/29/2017] [Accepted: 09/04/2017] [Indexed: 12/25/2022]
Affiliation(s)
- Marta Gawor
- Laboratory of Synaptogenesis; Nencki Institute of Experimental Biology; Polish Academy of Sciences Warsaw Poland
| | - Tomasz J. Prószyński
- Laboratory of Synaptogenesis; Nencki Institute of Experimental Biology; Polish Academy of Sciences Warsaw Poland
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14
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Dystrophin Dp71 Isoforms Are Differentially Expressed in the Mouse Brain and Retina: Report of New Alternative Splicing and a Novel Nomenclature for Dp71 Isoforms. Mol Neurobiol 2017; 55:1376-1386. [PMID: 28127699 DOI: 10.1007/s12035-017-0405-x] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2016] [Accepted: 01/12/2017] [Indexed: 12/27/2022]
Abstract
Multiple dystrophin Dp71 isoforms have been identified in rats, mice, and humans and in several cell line models. These Dp71 isoforms are produced by the alternative splicing of exons 71 to 74 and 78 and intron 77. Three main groups of Dp71 proteins are defined based on their C-terminal specificities: Dp71d, Dp71f, and Dp71e. Dp71 is highly expressed in the brain and retina; however, the specific isoforms present in these tissues have not been determined to date. In this work, we explored the expression of Dp71 isoforms in the mouse brain and retina using RT-PCR assays followed by the cloning of PCR products into the pGEM-T Easy vector, which was used to transform DH5α cells. Dp71-positive colonies were later analyzed by PCR multiplex and DNA sequencing to determine the alternative splicing. We thus demonstrated the expression of Dp71 transcripts corresponding to Dp71, Dp71a, Dp71c, Dp71b, Dp71ab, Dp71 Δ110, and novel Dp71 isoforms spliced in exon 74; 71 and 74; 71, 73 and 74; and 74 and 78, which we named Dp71d Δ74 , Dp71d Δ71,74 , Dp71d Δ71,73-74 , and Dp71f Δ74 , respectively. Additionally, we demonstrated that the Dp71d group of isoforms is highly expressed in the brain, while the Dp71f group predominates in the retina, at both the cDNA and protein levels. These findings suggest that distinct Dp71 isoforms may play different roles in the brain and retina.
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15
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Zhao J, Kodippili K, Yue Y, Hakim CH, Wasala L, Pan X, Zhang K, Yang NN, Duan D, Lai Y. Dystrophin contains multiple independent membrane-binding domains. Hum Mol Genet 2016; 25:3647-3653. [PMID: 27378693 DOI: 10.1093/hmg/ddw210] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2016] [Revised: 06/14/2016] [Accepted: 06/27/2016] [Indexed: 01/09/2023] Open
Abstract
Dystrophin is a large sub-sarcolemmal protein. Its absence leads to Duchenne muscular dystrophy (DMD). Binding to the sarcolemma is essential for dystrophin to protect muscle from contraction-induced injury. It has long been thought that membrane binding of dystrophin depends on its cysteine-rich (CR) domain. Here, we provide in vivo evidence suggesting that dystrophin contains three additional membrane-binding domains including spectrin-like repeats (R)1-3, R10-12 and C-terminus (CT). To systematically study dystrophin membrane binding, we split full-length dystrophin into ten fragments and examined subcellular localizations of each fragment by adeno-associated virus-mediated gene transfer. In skeletal muscle, R1-3, CR domain and CT were exclusively localized at the sarcolemma. R10-12 showed both cytosolic and sarcolemmal localization. Importantly, the CR-independent membrane binding was conserved in murine and canine muscles. A critical function of the CR-mediated membrane interaction is the assembly of the dystrophin-associated glycoprotein complex (DGC). While R1-3 and R10-12 did not restore the DGC, surprisingly, CT alone was sufficient to establish the DGC at the sarcolemma. Additional studies suggest that R1-3 and CT also bind to the sarcolemma in the heart, though relatively weak. Taken together, our study provides the first conclusive in vivo evidence that dystrophin contains multiple independent membrane-binding domains. These structurally and functionally distinctive membrane-binding domains provide a molecular framework for dystrophin to function as a shock absorber and signaling hub. Our results not only shed critical light on dystrophin biology and DMD pathogenesis, but also provide a foundation for rationally engineering minimized dystrophins for DMD gene therapy.
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Affiliation(s)
- Junling Zhao
- Department of Molecular Microbiology and Immunology, School of Medicine
| | - Kasun Kodippili
- Department of Molecular Microbiology and Immunology, School of Medicine
| | - Yongping Yue
- Department of Molecular Microbiology and Immunology, School of Medicine
| | - Chady H Hakim
- Department of Molecular Microbiology and Immunology, School of Medicine.,National Center for Advancing Translational Sciences, NIH, Rockville, MD, USA
| | - Lakmini Wasala
- Department of Molecular Microbiology and Immunology, School of Medicine
| | - Xiufang Pan
- Department of Molecular Microbiology and Immunology, School of Medicine
| | - Keqing Zhang
- Department of Molecular Microbiology and Immunology, School of Medicine
| | - Nora N Yang
- National Center for Advancing Translational Sciences, NIH, Rockville, MD, USA
| | - Dongsheng Duan
- Department of Molecular Microbiology and Immunology, School of Medicine .,Department of Neurology, School of Medicine.,Department of Bioengineering.,Department of Biomedical Sciences, College of Veterinary Medicine, University of Missouri, Columbia, MO, USA
| | - Yi Lai
- Department of Molecular Microbiology and Immunology, School of Medicine
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16
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Allen DG, Whitehead NP, Froehner SC. Absence of Dystrophin Disrupts Skeletal Muscle Signaling: Roles of Ca2+, Reactive Oxygen Species, and Nitric Oxide in the Development of Muscular Dystrophy. Physiol Rev 2016; 96:253-305. [PMID: 26676145 DOI: 10.1152/physrev.00007.2015] [Citation(s) in RCA: 272] [Impact Index Per Article: 34.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Dystrophin is a long rod-shaped protein that connects the subsarcolemmal cytoskeleton to a complex of proteins in the surface membrane (dystrophin protein complex, DPC), with further connections via laminin to other extracellular matrix proteins. Initially considered a structural complex that protected the sarcolemma from mechanical damage, the DPC is now known to serve as a scaffold for numerous signaling proteins. Absence or reduced expression of dystrophin or many of the DPC components cause the muscular dystrophies, a group of inherited diseases in which repeated bouts of muscle damage lead to atrophy and fibrosis, and eventually muscle degeneration. The normal function of dystrophin is poorly defined. In its absence a complex series of changes occur with multiple muscle proteins showing reduced or increased expression or being modified in various ways. In this review, we will consider the various proteins whose expression and function is changed in muscular dystrophies, focusing on Ca(2+)-permeable channels, nitric oxide synthase, NADPH oxidase, and caveolins. Excessive Ca(2+) entry, increased membrane permeability, disordered caveolar function, and increased levels of reactive oxygen species are early changes in the disease, and the hypotheses for these phenomena will be critically considered. The aim of the review is to define the early damage pathways in muscular dystrophy which might be appropriate targets for therapy designed to minimize the muscle degeneration and slow the progression of the disease.
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Affiliation(s)
- David G Allen
- Sydney Medical School & Bosch Institute, University of Sydney, New South Wales, Australia; and Department of Physiology & Biophysics, University of Washington, Seattle, Washington
| | - Nicholas P Whitehead
- Sydney Medical School & Bosch Institute, University of Sydney, New South Wales, Australia; and Department of Physiology & Biophysics, University of Washington, Seattle, Washington
| | - Stanley C Froehner
- Sydney Medical School & Bosch Institute, University of Sydney, New South Wales, Australia; and Department of Physiology & Biophysics, University of Washington, Seattle, Washington
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17
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Rau F, Lainé J, Ramanoudjame L, Ferry A, Arandel L, Delalande O, Jollet A, Dingli F, Lee KY, Peccate C, Lorain S, Kabashi E, Athanasopoulos T, Koo T, Loew D, Swanson MS, Le Rumeur E, Dickson G, Allamand V, Marie J, Furling D. Abnormal splicing switch of DMD's penultimate exon compromises muscle fibre maintenance in myotonic dystrophy. Nat Commun 2015; 6:7205. [PMID: 26018658 PMCID: PMC4458869 DOI: 10.1038/ncomms8205] [Citation(s) in RCA: 69] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2015] [Accepted: 04/16/2015] [Indexed: 02/06/2023] Open
Abstract
Myotonic Dystrophy type 1 (DM1) is a dominant neuromuscular disease caused by nuclear-retained RNAs containing expanded CUG repeats. These toxic RNAs alter the activities of RNA splicing factors resulting in alternative splicing misregulation and muscular dysfunction. Here we show that the abnormal splicing of DMD exon 78 found in dystrophic muscles of DM1 patients is due to the functional loss of MBNL1 and leads to the re-expression of an embryonic dystrophin in place of the adult isoform. Forced expression of embryonic dystrophin in zebrafish using an exon-skipping approach severely impairs the mobility and muscle architecture. Moreover, reproducing Dmd exon 78 missplicing switch in mice induces muscle fibre remodelling and ultrastructural abnormalities including ringed fibres, sarcoplasmic masses or Z-band disorganization, which are characteristic features of dystrophic DM1 skeletal muscles. Thus, we propose that splicing misregulation of DMD exon 78 compromises muscle fibre maintenance and contributes to the progressive dystrophic process in DM1.
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Affiliation(s)
- Frédérique Rau
- Sorbonne Universités, UPMC Univ Paris 06, INSERM UMRS974, CNRS FRE3617, Center for Research in Myology, Institut de Myologie, GH Pitié-Salpêtrière, F-75013 Paris, France
| | - Jeanne Lainé
- Sorbonne Universités, UPMC Univ Paris 06, INSERM UMRS974, CNRS FRE3617, Center for Research in Myology, Institut de Myologie, GH Pitié-Salpêtrière, F-75013 Paris, France.,Sorbonne Universités, UPMC Paris 06, Département de Physiologie, Site Pitié-Salpêtrière, F-75013 Paris, France
| | - Laetitita Ramanoudjame
- Sorbonne Universités, UPMC Univ Paris 06, INSERM UMRS974, CNRS FRE3617, Center for Research in Myology, Institut de Myologie, GH Pitié-Salpêtrière, F-75013 Paris, France
| | - Arnaud Ferry
- Sorbonne Universités, UPMC Univ Paris 06, INSERM UMRS974, CNRS FRE3617, Center for Research in Myology, Institut de Myologie, GH Pitié-Salpêtrière, F-75013 Paris, France
| | - Ludovic Arandel
- Sorbonne Universités, UPMC Univ Paris 06, INSERM UMRS974, CNRS FRE3617, Center for Research in Myology, Institut de Myologie, GH Pitié-Salpêtrière, F-75013 Paris, France
| | - Olivier Delalande
- Université de Rennes 1, Institut de Génétique et Développement de Rennes, F-35043 Rennes, France
| | - Arnaud Jollet
- Sorbonne Universités, UPMC Univ Paris 06, INSERM UMRS974, CNRS FRE3617, Center for Research in Myology, Institut de Myologie, GH Pitié-Salpêtrière, F-75013 Paris, France
| | - Florent Dingli
- Institut Curie, Centre de Recherche, Laboratoire de Spectrométrie de Masse Protéomique, F-75005 Paris, France
| | - Kuang-Yung Lee
- Department of Molecular Genetics and Microbiology, Center for NeuroGenetics and the Genetics Institute, University of Florida, College of Medicine, Gainesville, Florida 32610, USA.,Department of Neurology, Chang Gung Memorial Hospital, Keelung 204, Taiwan
| | - Cécile Peccate
- Sorbonne Universités, UPMC Univ Paris 06, INSERM UMRS974, CNRS FRE3617, Center for Research in Myology, Institut de Myologie, GH Pitié-Salpêtrière, F-75013 Paris, France
| | - Stéphanie Lorain
- Sorbonne Universités, UPMC Univ Paris 06, INSERM UMRS974, CNRS FRE3617, Center for Research in Myology, Institut de Myologie, GH Pitié-Salpêtrière, F-75013 Paris, France
| | - Edor Kabashi
- Sorbonne Université, UPMC Univ Paris 06, UM 75, INSERM U1127, CNRS UMR7225, ICM, Paris, F-75013 Paris, France
| | - Takis Athanasopoulos
- School of Biological Sciences, Royal Holloway-University of London, Egham, Surrey, TW20 0EX, UK
| | - Taeyoung Koo
- School of Biological Sciences, Royal Holloway-University of London, Egham, Surrey, TW20 0EX, UK
| | - Damarys Loew
- Institut Curie, Centre de Recherche, Laboratoire de Spectrométrie de Masse Protéomique, F-75005 Paris, France
| | - Maurice S Swanson
- Department of Molecular Genetics and Microbiology, Center for NeuroGenetics and the Genetics Institute, University of Florida, College of Medicine, Gainesville, Florida 32610, USA
| | - Elisabeth Le Rumeur
- Université de Rennes 1, Institut de Génétique et Développement de Rennes, F-35043 Rennes, France
| | - George Dickson
- School of Biological Sciences, Royal Holloway-University of London, Egham, Surrey, TW20 0EX, UK
| | - Valérie Allamand
- Sorbonne Universités, UPMC Univ Paris 06, INSERM UMRS974, CNRS FRE3617, Center for Research in Myology, Institut de Myologie, GH Pitié-Salpêtrière, F-75013 Paris, France
| | - Joëlle Marie
- Sorbonne Universités, UPMC Univ Paris 06, INSERM UMRS974, CNRS FRE3617, Center for Research in Myology, Institut de Myologie, GH Pitié-Salpêtrière, F-75013 Paris, France
| | - Denis Furling
- Sorbonne Universités, UPMC Univ Paris 06, INSERM UMRS974, CNRS FRE3617, Center for Research in Myology, Institut de Myologie, GH Pitié-Salpêtrière, F-75013 Paris, France
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18
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Dystrophin complex functions as a scaffold for signalling proteins. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2014; 1838:635-42. [DOI: 10.1016/j.bbamem.2013.08.023] [Citation(s) in RCA: 135] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/27/2013] [Revised: 08/22/2013] [Accepted: 08/28/2013] [Indexed: 11/23/2022]
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19
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Vulin A, Wein N, Strandjord DM, Johnson EK, Findlay AR, Maiti B, Howard MT, Kaminoh YJ, Taylor LE, Simmons TR, Ray WC, Montanaro F, Ervasti JM, Flanigan KM. The ZZ domain of dystrophin in DMD: making sense of missense mutations. Hum Mutat 2013; 35:257-64. [PMID: 24302611 DOI: 10.1002/humu.22479] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2013] [Accepted: 10/28/2013] [Indexed: 12/28/2022]
Abstract
Duchenne muscular dystrophy (DMD) is associated with the loss of dystrophin, which plays an important role in myofiber integrity via interactions with β-dystroglycan and other members of the transmembrane dystrophin-associated protein complex. The ZZ domain, a cysteine-rich zinc-finger domain near the dystrophin C-terminus, is implicated in forming a stable interaction between dystrophin and β-dystroglycan, but the mechanism of pathogenesis of ZZ missense mutations has remained unclear because not all such mutations have been shown to alter β-dystroglycan binding in previous experimental systems. We engineered three ZZ mutations (p.Cys3313Phe, p.Asp3335His, and p.Cys3340Tyr) into a short construct similar to the Dp71 dystrophin isoform for in vitro and in vivo studies and delineated their effect on protein expression, folding properties, and binding partners. Our results demonstrate two distinct pathogenic mechanisms for ZZ missense mutations. The cysteine mutations result in diminished or absent subsarcolemmal expression because of protein instability, likely due to misfolding. In contrast, the aspartic acid mutation disrupts binding with β-dystroglycan despite an almost normal expression at the membrane, confirming a role for the ZZ domain in β-dystroglycan binding but surprisingly demonstrating that such binding is not required for subsarcolemmal localization of dystrophin, even in the absence of actin binding domains.
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Affiliation(s)
- Adeline Vulin
- The Center for Gene Therapy, The Research Institute at Nationwide Children's Hospital, Columbus, Ohio
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20
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Ordered disorder of the astrocytic dystrophin-associated protein complex in the norm and pathology. PLoS One 2013; 8:e73476. [PMID: 24014171 PMCID: PMC3754965 DOI: 10.1371/journal.pone.0073476] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2013] [Accepted: 07/19/2013] [Indexed: 12/13/2022] Open
Abstract
The abundance and potential functional roles of intrinsically disordered regions in aquaporin-4, Kir4.1, a dystrophin isoforms Dp71, α-1 syntrophin, and α-dystrobrevin; i.e., proteins constituting the functional core of the astrocytic dystrophin-associated protein complex (DAPC), are analyzed by a wealth of computational tools. The correlation between protein intrinsic disorder, single nucleotide polymorphisms (SNPs) and protein function is also studied together with the peculiarities of structural and functional conservation of these proteins. Our study revealed that the DAPC members are typical hybrid proteins that contain both ordered and intrinsically disordered regions. Both ordered and disordered regions are important for the stabilization of this complex. Many disordered binding regions of these five proteins are highly conserved among vertebrates. Conserved eukaryotic linear motifs and molecular recognition features found in the disordered regions of five protein constituting DAPC likely enhance protein-protein interactions that are required for the cellular functions of this complex. Curiously, the disorder-based binding regions are rarely affected by SNPs suggesting that these regions are crucial for the biological functions of their corresponding proteins.
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21
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Bhat HF, Adams ME, Khanday FA. Syntrophin proteins as Santa Claus: role(s) in cell signal transduction. Cell Mol Life Sci 2013; 70:2533-54. [PMID: 23263165 PMCID: PMC11113789 DOI: 10.1007/s00018-012-1233-9] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2012] [Revised: 11/21/2012] [Accepted: 12/03/2012] [Indexed: 11/30/2022]
Abstract
Syntrophins are a family of cytoplasmic membrane-associated adaptor proteins, characterized by the presence of a unique domain organization comprised of a C-terminal syntrophin unique (SU) domain and an N-terminal pleckstrin homology (PH) domain that is split by insertion of a PDZ domain. Syntrophins have been recognized as an important component of many signaling events, and they seem to function more like the cell's own personal 'Santa Claus' that serves to 'gift' various signaling complexes with precise proteins that they 'wish for', and at the same time care enough for the spatial, temporal control of these signaling events, maintaining overall smooth functioning and general happiness of the cell. Syntrophins not only associate various ion channels and signaling proteins to the dystrophin-associated protein complex (DAPC), via a direct interaction with dystrophin protein but also serve as a link between the extracellular matrix and the intracellular downstream targets and cell cytoskeleton by interacting with F-actin. They play an important role in regulating the postsynaptic signal transduction, sarcolemmal localization of nNOS, EphA4 signaling at the neuromuscular junction, and G-protein mediated signaling. In our previous work, we reported a differential expression pattern of alpha-1-syntrophin (SNTA1) protein in esophageal and breast carcinomas. Implicated in several other pathologies, like cardiac dys-functioning, muscular dystrophies, diabetes, etc., these proteins provide a lot of scope for further studies. The present review focuses on the role of syntrophins in membrane targeting and regulation of cellular proteins, while highlighting their relevance in possible development and/or progression of pathologies including cancer which we have recently demonstrated.
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Affiliation(s)
- Hina F Bhat
- Department of Biotechnology, University of Kashmir, Srinagar, Jammu and Kashmir, India.
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22
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Maudsley S, Patel SA, Park SS, Luttrell LM, Martin B. Functional signaling biases in G protein-coupled receptors: Game Theory and receptor dynamics. Mini Rev Med Chem 2012; 12:831-40. [PMID: 22681251 PMCID: PMC6013268 DOI: 10.2174/138955712800959071] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2010] [Revised: 09/03/2011] [Accepted: 09/04/2011] [Indexed: 11/22/2022]
Abstract
Pharmacotherapeutic targeting of G protein-coupled receptors (GPCRs) is perhaps the most important field of drug design, as agents designed to control these receptors constitute more than half of the pharmacopeia. Initially GPCRs were considered to be unitary entities, possessing all of their potential functionality in their characteristic heptahelical core. Early models of the functional activity of GPCRs considered them to possess just a simple 'on' or 'off' status. Recent research however has allowed us to realize that GPCR functionality is dependent upon many other proteins outside of the heptahelical core, on the site of GPCR expression in a tissue or a microdomain in a cell, and, most importantly, on the formation of differential 'active' states preferentially coupled to specific signal transduction structures. The recognition of such signaling diversity has facilitated the ability to appreciate and identify ligands for GPCRs that demonstrate a bias towards one signaling form of a receptor to another. However while potentially increasing our ability for selective signal targeting, our approach to understanding the physiological ramifications of systemic signaling manipulation is underdeveloped. This explosion in the complexity of GPCR signaling is now becoming familiar territory to receptor biologists, yet the application of this knowledge to drug design is relatively limited. This review will attempt to outline potential pitfalls and unseen benefits of using signaling bias in therapeutic design as well as highlighting new applications such as Game Theory for uncovering new therapeutic applications for biased agonists.
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Affiliation(s)
- S Maudsley
- Receptor Pharmacology Unit, National Institute on Aging, National Institutes of Health, Baltimore, MD 21224, USA.
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23
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Abstract
The extracellular matrix (ECM) provides a solid scaffold and signals to cells through ECM receptors. The cell-matrix interactions are crucial for normal biological processes and when disrupted they may lead to pathological processes. In particular, the biological importance of ECM-cell membrane-cytoskeleton interactions in skeletal muscle is accentuated by the number of inherited muscle diseases caused by mutations in proteins conferring these interactions. In this review we introduce laminins, collagens, dystroglycan, integrins, dystrophin and sarcoglycans. Mutations in corresponding genes cause various forms of muscular dystrophy. The muscle disorders are presented as well as advances toward the development of treatment.
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Affiliation(s)
- Virginie Carmignac
- Muscle Biology Unit, Department of Experimental Medical Science, Lund University, Lund, Sweden
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24
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Saint Martín A, Aragón J, Depardon-Benítez F, Sánchez-Trujillo A, Mendoza-Hernández G, Ceja V, Montañez C. Identification of Dp71e, a new dystrophin with a novel carboxy-terminal end. FEBS J 2011; 279:66-77. [DOI: 10.1111/j.1742-4658.2011.08399.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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25
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Barresi R. From proteins to genes: immunoanalysis in the diagnosis of muscular dystrophies. Skelet Muscle 2011; 1:24. [PMID: 21798100 PMCID: PMC3156647 DOI: 10.1186/2044-5040-1-24] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2011] [Accepted: 06/24/2011] [Indexed: 12/23/2022] Open
Abstract
Muscular dystrophies are a large heterogeneous group of inherited diseases that cause progressive muscle weakness and permanent muscle damage. Very few muscular dystrophies show sufficient specific clinical features to allow a definite diagnosis. Because of the currently limited capacity to screen for numerous genes simultaneously, muscle biopsy is a time and cost-effective test for many of these disorders. Protein analysis interpreted in correlation with the clinical phenotype is a useful way of directing genetic testing in many types of muscular dystrophies. Immunohistochemistry and western blot are complementary techniques used to gather quantitative and qualitative information on the expression of proteins involved in this group of diseases. Immunoanalysis has a major diagnostic application mostly in recessive conditions where the absence of labelling for a particular protein is likely to indicate a defect in that gene. However, abnormalities in protein expression can vary from absence to very subtle reduction. It is good practice to test muscle biopsies with antibodies for several proteins simultaneously and to interpret the results in context. Indeed, there is a degree of direct or functional association between many of these proteins that is reflected by the presence of specific secondary abnormalities that are of value, especially when the diagnosis is not straightforward.
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Affiliation(s)
- Rita Barresi
- NCG Diagnostic & Advisory Service for Rare Neuromuscular Diseases, Muscle Immunoanalysis Unit, Dental Hospital, Richardson Road, Newcastle upon Tyne, UK.
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26
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Koo T, Malerba A, Athanasopoulos T, Trollet C, Boldrin L, Ferry A, Popplewell L, Foster H, Foster K, Dickson G. Delivery of AAV2/9-microdystrophin genes incorporating helix 1 of the coiled-coil motif in the C-terminal domain of dystrophin improves muscle pathology and restores the level of α1-syntrophin and α-dystrobrevin in skeletal muscles of mdx mice. Hum Gene Ther 2011; 22:1379-88. [PMID: 21453126 DOI: 10.1089/hum.2011.020] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Duchenne muscular dystrophy is a severe X-linked inherited muscle wasting disorder caused by mutations in the dystrophin gene. Adeno-associated virus (AAV) vectors have been extensively used to deliver genes efficiently for dystrophin expression in skeletal muscles. To overcome limited packaging capacity of AAV vectors (<5 kb), truncated recombinant microdystrophin genes with deletions of most of rod and carboxyl-terminal (CT) domains of dystrophin have been developed. We have previously shown the efficiency of mRNA sequence-optimized microdystrophin (ΔR4-23/ΔCT, called MD1) with deletion of spectrin-like repeat domain 4 to 23 and CT domain in ameliorating the pathology of dystrophic mdx mice. However, the CT domain of dystrophin is thought to recruit part of the dystrophin-associated protein complex, which acts as a mediator of signaling between extracellular matrix and cytoskeleton in muscle fibers. In this study, we extended the ΔR4-23/ΔCT microdystrophin by incorporating helix 1 of the coiled-coil motif in the CT domain of dystrophin (MD2), which contains the α1-syntrophin and α-dystrobrevin binding sites. Intramuscular injection of AAV2/9 expressing CT domain-extended microdystrophin showed efficient dystrophin expression in tibialis anterior muscles of mdx mice. The presence of the CT domain of dystrophin in MD2 increased the recruitment of α1-syntrophin and α-dystrobrevin at the sarcolemma and significantly improved the muscle resistance to lengthening contraction-induced muscle damage in the mdx mice compared with MD1. These results suggest that the incorporation of helix 1 of the coiled-coil motif in the CT domain of dystrophin to the microdystrophins will substantially improve their efficiency in restoring muscle function in patients with Duchenne muscular dystrophy.
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Affiliation(s)
- Taeyoung Koo
- SWAN Institute of Biomedical and Life Sciences, School of Biological Sciences, Royal Holloway University of London, Egham, Surrey TW20 0EX, United Kingdom
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Ozawa E. Our trails and trials in the subsarcolemmal cytoskeleton network and muscular dystrophy researches in the dystrophin era. PROCEEDINGS OF THE JAPAN ACADEMY. SERIES B, PHYSICAL AND BIOLOGICAL SCIENCES 2010; 86:798-821. [PMID: 20948175 PMCID: PMC3037518 DOI: 10.2183/pjab.86.798] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/19/2010] [Accepted: 08/09/2010] [Indexed: 05/30/2023]
Abstract
In 1987, about 150 years after the discovery of Duchenne muscular dystrophy (DMD), its responsible gene, the dystrophin gene, was cloned by Kunkel. This was a new substance. During these 20 odd years after the cloning, our understanding on dystrophin as a component of the subsarcolemmal cytoskeleton networks and on the pathomechanisms of and experimental therapeutics for DMD has been greatly enhanced. During this paradigm change, I was fortunately able to work as an active researcher on its frontiers for 12 years. After we discovered that dystrophin is located on the cell membrane in 1988, we studied the architecture of dystrophin and dystrophin-associated proteins (DAPs) complex in order to investigate the function of dystrophin and pathomechanism of DMD. During the conduct of these studies, we came to consider that the dystrophin-DAP complex serves to transmembranously connect the subsarcolemmal cytoskeleton networks and basal lamina to protect the lipid bilayer. It then became our working hypothesis that injury of the lipid bilayer upon muscle contraction is the cause of DMD. During this process, we predicted that subunits of the sarcoglycan (SG) complex are responsible for respective types of DMD-like muscular dystrophy with autosomal recessive inheritance. Our prediction was confirmed to be true by many researchers including ourselves. In this review, I will try to explain what we observed and how we considered concerning the architecture and function of the dystrophin-DAP complex, and the pathomechanisms of DMD and related muscular dystrophies.
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Affiliation(s)
- Eijiro Ozawa
- National Center of Neuroscience, NCNP, Kodairashi, Tokyo 187-8502, Japan.
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28
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Townsend D, Yasuda S, Chamberlain J, Metzger JM. Cardiac consequences to skeletal muscle-centric therapeutics for Duchenne muscular dystrophy. Trends Cardiovasc Med 2009; 19:50-55. [PMID: 19577712 DOI: 10.1016/j.tcm.2009.04.006] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
Duchenne muscular dystrophy (DMD) is a fatal disease of muscle deterioration. Duchenne muscular dystrophy affects all striated muscles in the body, including the heart. Recent advances in palliative care, largely directed at improving respiratory function, have extended life but paradoxically further unmasked emergent heart disease in DMD patients. New experimental strategies have shown promise in restoring dystrophin in the skeletal muscles of dystrophin- deficient animals. These strategies often have little or no capacity for restitution of dystrophin in the hearts of these animals. This article draws on both clinical data and recent experimental data to posit that effective skeletal muscle restricted therapies for DMD will paradoxically heighten cardiomyopathy and heart failure in these patients.
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Affiliation(s)
- DeWayne Townsend
- Department of Integrative Biology and Physiology, University of Minnesota, Minneapolis, MN 55455, USA.
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Lai Y, Thomas GD, Yue Y, Yang HT, Li D, Long C, Judge L, Bostick B, Chamberlain JS, Terjung RL, Duan D. Dystrophins carrying spectrin-like repeats 16 and 17 anchor nNOS to the sarcolemma and enhance exercise performance in a mouse model of muscular dystrophy. J Clin Invest 2009; 119:624-35. [PMID: 19229108 DOI: 10.1172/jci36612] [Citation(s) in RCA: 282] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2008] [Accepted: 01/07/2009] [Indexed: 11/17/2022] Open
Abstract
Sarcolemma-associated neuronal NOS (nNOS) plays a critical role in normal muscle physiology. In Duchenne muscular dystrophy (DMD), the loss of sarcolemmal nNOS leads to functional ischemia and muscle damage; however, the mechanism of nNOS subcellular localization remains incompletely understood. According to the prevailing model, nNOS is recruited to the sarcolemma by syntrophin, and in DMD this localization is altered. Intriguingly, the presence of syntrophin on the membrane does not always restore sarcolemmal nNOS. Thus, we wished to determine whether dystrophin functions in subcellular localization of nNOS and which regions may be necessary. Using in vivo transfection of dystrophin deletion constructs, we show that sarcolemmal targeting of nNOS was dependent on the spectrin-like repeats 16 and 17 (R16/17) within the rod domain. Treatment of mdx mice (a DMD model) with R16/17-containing synthetic dystrophin genes effectively ameliorated histological muscle pathology and improved muscle strength as well as exercise performance. Furthermore, sarcolemma-targeted nNOS attenuated alpha-adrenergic vasoconstriction in contracting muscle and improved muscle perfusion during exercise as measured by Doppler and microsphere circulation. In summary, we have identified the dystrophin spectrin-like repeats 16 and 17 as a novel scaffold for nNOS sarcolemmal targeting. These data suggest that muscular dystrophy gene therapies based on R16/17-containing dystrophins may yield better clinical outcomes than the current therapies.
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Affiliation(s)
- Yi Lai
- Department of Molecular Microbiology and Immunology, University of Missouri, One Hospital Drive, Columbia, MO 65212, USA
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Kimura S, Ito K, Ueno H, Ikezawa M, Takeshima Y, Yoshioka K, Ozasa S, Nakamura K, Nomura K, Matsukura M, Mitsui K, Matsuo M, Miike T. A 2-bp deletion in exon 74 of the dystrophin gene does not clearly induce muscle weakness. Brain Dev 2009; 31:169-72. [PMID: 18430534 DOI: 10.1016/j.braindev.2008.03.004] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/07/2007] [Revised: 03/10/2008] [Accepted: 03/12/2008] [Indexed: 11/26/2022]
Abstract
Duchenne muscular dystrophy (DMD) is caused by mutation of the dystrophin gene. Cases of dystrophinopathy with a 2-bp deletion in the dystrophin gene commonly result in DMD. We report here a case of dystrophinopathy in a 9-years-old boy with a 2-bp deletion in exon 74 of the dystrophin gene; however, the boy had no clear clinical signs of muscle weakness. Immunohistochemical studies with N-terminal (DYS3) and rod-domain anti-dystrophin (DYS1) antibodies revealed that the dystrophin signals were weaker than in the control sample (non-dystrophinopathy) at the sarcolemma of myofibers, and the studies with C-terminus anti-dystrophin antibody (DYS2) were negative. Our patient's mutation is located between the binding sites of alpha-syntrophin and alpha-dystrobrevin. These results suggest that this mutation does not clearly induce muscle weakness at least through the age of 9 years.
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Affiliation(s)
- Shigemi Kimura
- Department of Child Development, Kumamoto University Graduate School, 1-1-1 Honjou, Kumamoto 860-0811, Japan.
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31
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Hwa HL, Chang YY, Huang CH, Chen CH, Kao YS, Jong YJ, Chao MC, Ko TM. Small Mutations of the DMD Gene in Taiwanese Families. J Formos Med Assoc 2008; 107:463-9. [DOI: 10.1016/s0929-6646(08)60154-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022] Open
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32
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Ervasti JM, Sonnemann KJ. Biology of the striated muscle dystrophin-glycoprotein complex. INTERNATIONAL REVIEW OF CYTOLOGY 2008; 265:191-225. [PMID: 18275889 DOI: 10.1016/s0074-7696(07)65005-0] [Citation(s) in RCA: 110] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/04/2022]
Abstract
Since its first description in 1990, the dystrophin-glycoprotein complex has emerged as a critical nexus for human muscular dystrophies arising from defects in a variety of distinct genes. Studies in mammals widely support a primary role for the dystrophin-glycoprotein complex in mechanical stabilization of the plasma membrane in striated muscle and provide hints for secondary functions in organizing molecules involved in cellular signaling. Studies in model organisms confirm the importance of the dystrophin-glycoprotein complex for muscle cell viability and have provided new leads toward a full understanding of its secondary roles in muscle biology.
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Affiliation(s)
- James M Ervasti
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, Minnesota 55455, USA
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33
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Nakamori M, Kimura T, Fujimura H, Takahashi MP, Sakoda S. Altered mRNA splicing of dystrophin in type 1 myotonic dystrophy. Muscle Nerve 2007; 36:251-7. [PMID: 17487865 DOI: 10.1002/mus.20809] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Myotonic dystrophy type1 (DM1) is a multisystemic disorder caused by a CTG repeat expansion in the DMPK gene. Aberrant mRNA splicing of several genes has been reported to contribute to some of the symptoms, including myotonia and insulin resistance, but the cause of muscle wasting is unknown. Dystrophin is a cytoskeletal protein that is required for structural stability and signaling at the sarcolemma and has several spliced isoforms. We investigated the alternative splicing of dystrophin in skeletal and cardiac muscle of DM1 patients by using reverse transcriptase-polymerase chain reaction and found that dystrophin isoforms lacking exon 71 or 78, which is suggested to encode an important region for protein binding and hydrophobicity, were significantly increased. We suggest that the aberrantly spliced dystrophin is responsible for the muscle wasting in DM1.
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Affiliation(s)
- Masayuki Nakamori
- Department of Neurology, Osaka University Graduate School of Medicine, D-4, 2-2 Yamadaoka, Suita, Osaka 565-0871, Japan
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Alessi A, Bragg AD, Percival JM, Yoo J, Albrecht DE, Froehner SC, Adams ME. gamma-Syntrophin scaffolding is spatially and functionally distinct from that of the alpha/beta syntrophins. Exp Cell Res 2006; 312:3084-95. [PMID: 16857187 DOI: 10.1016/j.yexcr.2006.06.019] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2006] [Revised: 06/06/2006] [Accepted: 06/07/2006] [Indexed: 10/24/2022]
Abstract
The syntrophins are a family of scaffolding proteins with multiple protein interaction domains that link signaling proteins to dystrophin family members. Each of the three most characterized syntrophins (alpha, beta1, beta2) contains a PDZ domain that binds a unique set of signaling proteins including kinases, ion and water channels, and neuronal nitric oxide synthase (nNOS). The PDZ domains of the gamma-syntrophins do not bind nNOS. In vitro pull-down assays show that the gamma-syntrophins can bind dystrophin but have unique preferences for the syntrophin binding sites of dystrophin family members. Despite their ability to bind dystrophin in vitro, neither gamma-syntrophin isoform co-localizes with dystrophin in skeletal muscle. Furthermore, gamma-syntrophins do not co-purify with dystrophin isolated from mouse tissue. These data suggest that the interaction of gamma-syntrophin with dystrophin is transient and potentially subject to regulatory mechanisms. gamma1-Syntrophin is highly expressed in brain and is specifically localized in hippocampal pyramidal neurons, Purkinje neurons in cerebellum, and cortical neurons. gamma2-Syntrophin is expressed in many tissues including skeletal muscle where it is found only in the subsynaptic space beneath the neuromuscular junction. In both neurons and muscle, gamma-syntrophin isoforms localize to the endoplasmic reticulum where they may form a scaffold for signaling and trafficking.
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Affiliation(s)
- Amy Alessi
- Department of Physiology and Biophysics, University of Washington, 1959 Pacific ST NE, Seattle, WA 98195-7290, USA
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35
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Williams JC, Armesilla AL, Mohamed TMA, Hagarty CL, McIntyre FH, Schomburg S, Zaki AO, Oceandy D, Cartwright EJ, Buch MH, Emerson M, Neyses L. The sarcolemmal calcium pump, alpha-1 syntrophin, and neuronal nitric-oxide synthase are parts of a macromolecular protein complex. J Biol Chem 2006; 281:23341-8. [PMID: 16735509 DOI: 10.1074/jbc.m513341200] [Citation(s) in RCA: 120] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The main role of the plasma membrane Ca2+/calmodulin-dependent ATPase (PMCA) is in the removal of Ca2+ from the cytosol. Recently, we and others have suggested a new function for PMCA as a modulator of signal transduction pathways. This paper shows the physical interaction between PMCA (isoforms 1 and 4) and alpha-1 syntrophin and proposes a ternary complex of interaction between endogenous PMCA, alpha-1 syntrophin, and NOS-1 in cardiac cells. We have identified that the linker region between the pleckstrin homology 2 (PH2) and the syntrophin unique (SU) domains, corresponding to amino acids 399-447 of alpha-1 syntrophin, is crucial for interaction with PMCA1 and -4. The PH2 and the SU domains alone failed to interact with PMCA. The functionality of the interaction was demonstrated by investigating the inhibition of neuronal nitric-oxide synthase-1 (NOS-1); PMCA is a negative regulator of NOS-1-dependent NO production, and overexpression of alpha-1 syntrophin and PMCA4 resulted in strongly increased inhibition of NO production. Analysis of the expression levels of alpha-1 syntrophin protein in the heart, skeletal muscle, brain, uterus, kidney, or liver of PMCA4-/- mice, did not reveal any differences when compared with those found in the same tissues of wild-type mice. These results suggest that PMCA4 is tethered to the syntrophin complex as a regulator of NOS-1, but its absence does not cause collapse of the complex, contrary to what has been reported for other proteins within the complex, such as dystrophin. In conclusion, the present data demonstrate for the first time the localization of PMCA1b and -4b to the syntrophin.dystrophin complex in the heart and provide a specific molecular mechanism of interaction as well as functionality.
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Affiliation(s)
- Judith C Williams
- Division of Cardiology, Room 1.302 Stopford Building, The University of Manchester, Oxford Road, Manchester, M13 9PT, United Kingdom
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36
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Gaedigk R, Law DJ, Fitzgerald-Gustafson KM, McNulty SG, Nsumu NN, Modrcin AC, Rinaldi RJ, Pinson D, Fowler SC, Bilgen M, Burns J, Hauschka SD, White RA. Improvement in survival and muscle function in an mdx/utrn−/− double mutant mouse using a human retinal dystrophin transgene. Neuromuscul Disord 2006; 16:192-203. [PMID: 16487708 DOI: 10.1016/j.nmd.2005.12.007] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2005] [Accepted: 12/21/2005] [Indexed: 10/25/2022]
Abstract
Duchenne muscular dystrophy is a progressive muscle disease characterized by increasing muscle weakness and death by the third decade. mdx mice exhibit the underlying muscle disease but appear physically normal with ordinary lifespans, possibly due to compensatory expression of utrophin. In contrast, double mutant mice (mdx/utrn(-/-)), deficient for both dystrophin and utrophin die by approximately 3 months and suffer from severe muscle weakness, growth retardation, and severe spinal curvature. The capacity of human retinal dystrophin (Dp260) to compensate for the missing 427 kDa muscle dystrophin was tested in mdx/utrn(-/-) mice. Functional outcomes were assessed by histology, EMG, MRI, mobility, weight and longevity. MCK-driven transgenic expression of Dp260 in mdx/utrn(-/-) mice converts their disease course from a severe, lethal muscular dystrophy to a viable, mild myopathic phenotype. This finding is relevant to the design of exon-skipping therapeutic strategies since Dp260 lacks dystrophin exons 1-29.
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Affiliation(s)
- Roger Gaedigk
- Department of Medical Research, Children's Mercy Hospitals & Clinics, Pediatric Research Building 4th Floor, 2401 Gillham, Kansas City, MO 64108, USA
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37
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Abstract
A major role for Müller cells in the retina is to buffer changes in the extracellular K+ concentration ([K+]o) resulting from light-evoked neuronal activity. The primary K+ conductance in Müller cells is the inwardly rectifying K+ channel Kir4.1. Since this channel is constitutively active, K+ can enter or exit Müller cells depending on the state of the [K+]o. This process of [K+]o buffering by Müller cells ("K+ siphoning") is enhanced by the precise accumulation of these K+ channels at discrete subdomains of Müller cell membranes. Specifically, Kir4.1 is localized to the perivascular processes of Müller cells in animals with vascular retinas and to the endfeet of Müller cells in all species examined. The water channel aquaporin-4 (AQP4) also appears to be important for [K+]o buffering and is expressed in Müller cells in a very similar subcellular distribution pattern to that of Kir4.1. To gain a better understanding of how Müller cells selectively target K+ and water channels to discrete membrane subdomains, we addressed the question of whether Kir4.1 and AQP4 associate with the dystrophin-glycoprotein complex (DGC) in the mammalian retina. Immunoprecipitation (IP) experiments were utilized to show that Kir4.1 and AQP4 are associated with DGC proteins in rat retina. Furthermore, AQP4 was also shown to co-precipitate with Kir4.1, suggesting that both channels are tethered together by the DGC in Müller cells. This work further defines a subcellular localization mechanism in Müller cells that facilitates [K+]o buffering in the retina.
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Affiliation(s)
- Nathan C Connors
- Department of Neuroscience, University of Pennsylvania, Philadelphia, Pennsylvania, USA
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38
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Yan J, Wen W, Xu W, Long JF, Adams ME, Froehner SC, Zhang M. Structure of the split PH domain and distinct lipid-binding properties of the PH-PDZ supramodule of alpha-syntrophin. EMBO J 2005; 24:3985-95. [PMID: 16252003 PMCID: PMC1356300 DOI: 10.1038/sj.emboj.7600858] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2005] [Accepted: 10/10/2005] [Indexed: 11/09/2022] Open
Abstract
Pleckstrin homology (PH) domains play diverse roles in cytoskeletal dynamics and signal transduction. Split PH domains represent a unique subclass of PH domains that have been implicated in interactions with complementary partial PH domains 'hidden' in many proteins. Whether partial PH domains exist as independent structural units alone and whether two halves of a split PH domain can fold together to form an intact PH domain are not known. Here, we solved the structure of the PH(N)-PDZ-PH(C) tandem of alpha-syntrophin. The split PH domain of alpha-syntrophin adopts a canonical PH domain fold. The isolated partial PH domains of alpha-syntrophin, although completely unfolded, remain soluble in solution. Mixing of the two isolated domains induces de novo folding and yields a stable PH domain. Our results demonstrate that two complementary partial PH domains are capable of binding to each other to form an intact PH domain. We further showed that the PH(N)-PDZ-PH(C) tandem forms a functionally distinct supramodule, in which the split PH domain and the PDZ domain function synergistically in binding to inositol phospholipids.
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Affiliation(s)
- Jing Yan
- Department of Biochemistry, Molecular Neuroscience Center, Hong Kong University of Science and Technology, Hong Kong, People's Republic of China
| | - Wenyu Wen
- Department of Biochemistry, Molecular Neuroscience Center, Hong Kong University of Science and Technology, Hong Kong, People's Republic of China
| | - Weiguang Xu
- Department of Biochemistry, Molecular Neuroscience Center, Hong Kong University of Science and Technology, Hong Kong, People's Republic of China
| | - Jia-fu Long
- Department of Biochemistry, Molecular Neuroscience Center, Hong Kong University of Science and Technology, Hong Kong, People's Republic of China
| | - Marvin E Adams
- Department of Physiology and Biophysics, University of Washington, Seattle, Washington, DC, USA
| | - Stanley C Froehner
- Department of Physiology and Biophysics, University of Washington, Seattle, Washington, DC, USA
| | - Mingjie Zhang
- Department of Biochemistry, Molecular Neuroscience Center, Hong Kong University of Science and Technology, Hong Kong, People's Republic of China
- Department of Biochemistry, Molecular Neuroscience Center, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, People's Republic of China. Tel.: +852 2358 8709; Fax: +852 2358 1552; E-mail:
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Bordais A, Bolaños-Jimenez F, Fort P, Varela C, Sahel JA, Picaud S, Rendon A. Molecular cloning and protein expression of Duchenne muscular dystrophy gene products in porcine retina. Neuromuscul Disord 2005; 15:476-87. [PMID: 15941659 DOI: 10.1016/j.nmd.2005.03.011] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2004] [Revised: 03/17/2005] [Accepted: 03/24/2005] [Indexed: 10/25/2022]
Abstract
Due to the difference between rodent and human retinal circuitry, we characterize a new animal model of retinal perturbation in neurotransmission in Duchenne Muscular Dystrophy (DMD) patients. We investigated the expression and localization of dystrophin proteins and dystrophin associated proteins in porcine retina by reverse transcription polymerase chain reaction, Western blot analysis and immunohistochemistry. Homologues of human DMD gene products and alternative spliced isoforms of Dp71 were identified. We observed that dystrophins were expressed in the outer plexiform layer, around blood vessels and at the inner limiting membrane as previously described in human and mouse retinae. Moreover, by double immunostaining we showed that beta-dystroglycan co-localizes with dystrophin in the outer plexiform layer whereas alpha1-syntrophin labeling differs from that for dystrophins. Using confocal laser microscopy we observed that dystrophins labeling co-localizes with pre- and post-synaptic cell markers in the outer plexiform layer. We suggest that porcine retina constitutes a good model to study the role of dystrophins in retinal neurotransmission and should be used to investigate the physiological roles of dystrophins in signal transduction.
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Affiliation(s)
- Agnès Bordais
- Laboratoire de Physiopathologie Cellulaire et Moléculaire de la Rétine, INSERM U592, Hôpital Saint-Antoine, Bâtiment Kourilsky, 184 rue du Faubourg Saint-Antoine, 75571 Paris, France
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40
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Abstract
The dystrophin glycoprotein complex (DGC) is a specialization of cardiac and skeletal muscle membrane. This large multicomponent complex has both mechanical stabilizing and signaling roles in mediating interactions between the cytoskeleton, membrane, and extracellular matrix. Dystrophin, the protein product of the Duchenne and X-linked dilated cardiomyopathy locus, links cytoskeletal and membrane elements. Mutations in additional DGC genes, the sarcoglycans, also lead to cardiomyopathy and muscular dystrophy. Animal models of DGC mutants have shown that destabilization of the DGC leads to membrane fragility and loss of membrane integrity, resulting in degeneration of skeletal muscle and cardiomyocytes. Vascular reactivity is altered in response to primary degeneration in striated myocytes and arises from a vascular smooth muscle cell-extrinsic mechanism.
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MESH Headings
- Animals
- Cardiomyopathy, Dilated/genetics
- Cardiomyopathy, Dilated/therapy
- Caveolin 3
- Caveolins/physiology
- Cricetinae
- Cytoskeletal Proteins/chemistry
- Cytoskeletal Proteins/genetics
- Cytoskeletal Proteins/physiology
- Dystroglycans
- Dystrophin/chemistry
- Dystrophin/genetics
- Dystrophin/physiology
- Genetic Therapy
- Humans
- Laminin/genetics
- Laminin/physiology
- Macromolecular Substances
- Membrane Glycoproteins/chemistry
- Membrane Glycoproteins/genetics
- Membrane Glycoproteins/physiology
- Mesocricetus
- Mice
- Models, Molecular
- Muscle, Skeletal/ultrastructure
- Muscular Dystrophy, Animal/genetics
- Muscular Dystrophy, Animal/metabolism
- Muscular Dystrophy, Animal/pathology
- Muscular Dystrophy, Duchenne/genetics
- Muscular Dystrophy, Duchenne/metabolism
- Muscular Dystrophy, Duchenne/pathology
- Muscular Dystrophy, Duchenne/therapy
- Myocardium/ultrastructure
- Neuropeptides/chemistry
- Neuropeptides/genetics
- Neuropeptides/physiology
- Nitric Oxide Synthase/physiology
- Nitric Oxide Synthase Type I
- Protein Conformation
- Protein Structure, Tertiary
- Sarcolemma/physiology
- Sarcolemma/ultrastructure
- Sarcomeres/chemistry
- Sarcomeres/ultrastructure
- Stem Cell Transplantation
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Affiliation(s)
- Karen A Lapidos
- Department of Molecular Genetics and Cell Biology, University of Chicago, Ill 60637, USA
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41
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Macioce P, Gambara G, Bernassola M, Gaddini L, Torreri P, Macchia G, Ramoni C, Ceccarini M, Petrucci TC. β-Dystrobrevin interacts directly with kinesin heavy chain in brain. J Cell Sci 2003; 116:4847-56. [PMID: 14600269 DOI: 10.1242/jcs.00805] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
β-Dystrobrevin, a member of the dystrobrevin protein family, is a dystrophin-related and -associated protein restricted to non-muscle tissues and is highly expressed in kidney, liver and brain. Dystrobrevins are now thought to play an important role in intracellular signal transduction, in addition to providing a membrane scaffold in muscle, but the precise role of β-dystrobrevin has not yet been determined. To study β-dystrobrevin's function in brain, we used the yeast two-hybrid approach to look for interacting proteins. Four overlapping clones were identified that encoded Kif5A, a neuronal member of the Kif5 family of proteins that consists of the heavy chains of conventional kinesin. A direct interaction of β-dystrobrevin with Kif5A was confirmed by in vitro and in vivo association assays. Co-immunoprecipitation with a monoclonal kinesin heavy chain antibody precipitated both α- and β-dystrobrevin, indicating that this interaction is not restricted to the β-dystrobrevin isoform. The site for Kif5A binding to β-dystrobrevin was localized in a carboxyl-terminal region that seems to be important in heavy chain-mediated kinesin interactions and is highly homologous in all three Kif5 isoforms, Kif5A, Kif5B and Kif5C. Pull-down and immunofluorescence experiments also showed a direct interaction between β-dystrobrevin and Kif5B. Our findings suggest a novel function for dystrobrevin as a motor protein receptor that might play a major role in the transport of components of the dystrophin-associated protein complex to specific sites in the cell.
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Affiliation(s)
- P Macioce
- Laboratory of Cell Biology, Istituto Superiore di Sanità, Viale Regina Elena 299, 00161 Rome, Italy.
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42
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Grisoni K, Gieseler K, Mariol MC, Martin E, Carre-Pierrat M, Moulder G, Barstead R, Ségalat L. The stn-1 syntrophin gene of C.elegans is functionally related to dystrophin and dystrobrevin. J Mol Biol 2003; 332:1037-46. [PMID: 14499607 DOI: 10.1016/j.jmb.2003.08.021] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Syntrophins are a family of PDZ domain-containing adaptor proteins required for receptor localization. Syntrophins are also associated with the dystrophin complex in muscles. We report here the molecular and functional characterization of the Caenorhabditis elegans gene stn-1 (F30A10.8), which encodes a syntrophin with homology to vertebrate alpha and beta-syntrophins. stn-1 is expressed in neurons and in muscles of C.elegans. stn-1 mutants resemble dystrophin (dys-1) and dystrobrevin (dyb-1) mutants: they are hyperactive, bend their heads when they move forward, tend to hypercontract, and are hypersensitive to the acetylcholinesterase inhibitor aldicarb. These phenotypes are suppressed when stn-1 is expressed under the control of a muscular promoter, indicating that they are caused by the absence of stn-1 in muscles. These results suggest that the role of syntrophin is linked to dystrophin function in C.elegans.
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Affiliation(s)
- Karine Grisoni
- CGMC, CNRS-UMR 5534, Université Lyon-1, 43 Bid du 11 Novembre, 69622, Villeurbanne, cedex, France.
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43
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Hoshino S, Ohkoshi N, Ishii A, Shoji S. The expression of alpha-dystrobrevin and dystrophin during skeletal muscle regeneration. J Muscle Res Cell Motil 2003; 23:131-8. [PMID: 12416719 DOI: 10.1023/a:1020256316659] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
The expression of alpha-dystrobrevin and dystrophin in rat tibialis anterior muscles was chronologically evaluated during a cycle of regeneration after myonecrosis induced by the injection of cardiotoxin. In immunohistochemical studies, alpha-dystrobrevin and dystrophin were first stained weakly at the sarcolemma of some regenerating muscle fibers on day 5. On day 7, alpha-dystrobrevin was still stained weakly, whereas dystrophin was stained conspicuously. After day 10, alpha-dystrobrevin and dystrophin were both stained conspicuously on almost all regenerating muscle fibers. In the Western blot analysis, alpha-dystrobrevin and dystrophin were first detected as visible bands on days 5 and 7, respectively. The bands of alpha-dystrobrevin and dystrophin both darkened sequentially up to day 10. The protein levels based on the densitometrical analysis of the bands on each day were converted to the percentage of the protein level on day 28, which was taken as 100%. The sequential line based on these data showed that alpha-dystrobrevin and dystrophin reached 50% of the protein level on day 28 by 6.6 and 5.3 days, respectively. These data provide evidence that alpha-dystrobrevin regenerates more slowly than dystrophin in skeletal muscle.
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Affiliation(s)
- Sachiko Hoshino
- Department of Neurology, Institute of Clinical Medicine, University of Tsukuba, Japan
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44
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Ou Y, Strege P, Miller SM, Makielski J, Ackerman M, Gibbons SJ, Farrugia G. Syntrophin gamma 2 regulates SCN5A gating by a PDZ domain-mediated interaction. J Biol Chem 2003; 278:1915-23. [PMID: 12429735 DOI: 10.1074/jbc.m209938200] [Citation(s) in RCA: 91] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
SCN5A encodes the alpha subunit of the cardiac muscle and intestinal smooth muscle mechanosensitive Na(+) channel. Mechanosensitivity in the intestine requires an intact cytoskeleton. We report, using laser capture microdissection, single cell PCR, and immunohistochemistry, that syntrophins, scaffolding proteins, were expressed in human intestinal smooth muscle cells. The distribution of syntrophin gamma 2 was similar to that of SCN5A. Yeast two-hybrid and glutathione S-transferase pull-down experiments show that SCN5A and syntrophin gamma 2 co-express and that the PDZ domain of syntrophin gamma 2 directly interacts with the C terminus of SCN5A. In native cells, disruption of the C terminus-syntrophin gamma 2 PDZ domain interaction using peptides directed against either region result in loss of mechanosensitivity. Co-transfection of syntrophin gamma 2 with SCN5A in HEK293 cells markedly shifts the activation kinetics of SCN5A and reduces the availability of Na(+) current. We propose that syntrophin gamma 2 is an essential Na(+) channel-interacting protein required for the full expression of the Na(+) current and that the SCN5A-syntrophin gamma 2 interaction determines mechanosensitivity and current availability.
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Affiliation(s)
- Yijun Ou
- Enteric NeuroScience Program, Department of Physiology and Biophysics and Division of Gastroenterology and Hepatology, Mayo Clinic, Rochester, Minnesota 55905, USA
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45
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Wells KE, Torelli S, Lu Q, Brown SC, Partridge T, Muntoni F, Wells DJ. Relocalization of neuronal nitric oxide synthase (nNOS) as a marker for complete restoration of the dystrophin associated protein complex in skeletal muscle. Neuromuscul Disord 2003; 13:21-31. [PMID: 12467729 DOI: 10.1016/s0960-8966(02)00191-8] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
A lack of effective treatments for Duchenne muscular dystrophy, a fatal X-linked myopathy, has focused attention on the possibility of gene therapy. The aim of the gene therapy approach is the restoration of the dystrophin associated complex of proteins, one member of which is neuronal nitric oxide synthase, an important enzyme in signal transduction. Transgenic mdx mice and plasmid gene transfer of both human and murine recombinant dystrophins was used to assess whether nNOS could be restored to the sarcolemma following dystrophin gene transfer at a variety of levels of expression. Murine revertant fibres and human patients with different dystrophin deletions were used to assess the relationship between exon deletion and loss of neuronal nitric oxide synthase localization to the sarcolemma. We demonstrate that the domain encoded by exons 45-48 is required for localization of neuronal nitric oxide synthase to the sarcolemma. On the basis of these observations we suggest that neuronal nitric oxide synthase is a useful marker for complete restoration of the dystrophin associated complex and should be used as one of the criteria for selecting the recombinant molecule to be used for gene therapy in Duchenne muscular dystrophy.
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MESH Headings
- Adult
- Animals
- Biomarkers/analysis
- Calcium-Binding Proteins
- Cytoskeletal Proteins/metabolism
- Dystrophin/metabolism
- Exons
- Gene Transfer Techniques
- Humans
- Immunohistochemistry/methods
- Membrane Proteins/metabolism
- Mice
- Mice, Inbred C57BL
- Mice, Inbred mdx
- Mice, Transgenic
- Muscle Proteins/metabolism
- Muscle, Skeletal/enzymology
- Muscle, Skeletal/metabolism
- Muscle, Skeletal/pathology
- Muscular Dystrophy, Animal/enzymology
- Muscular Dystrophy, Duchenne/enzymology
- Muscular Dystrophy, Duchenne/metabolism
- Muscular Dystrophy, Duchenne/pathology
- Nitric Oxide Synthase/metabolism
- Nitric Oxide Synthase Type I
- Peptide Fragments/metabolism
- Sarcolemma/enzymology
- Utrophin
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Affiliation(s)
- Kim E Wells
- Department of Neuromuscular Diseases, Imperial College Faculty of Medicine, Charing Cross Hospital, St Dunstan's Road, W6 8RP, London, UK
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46
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Austin RC, Fox JEB, Werstuck GH, Stafford AR, Bulman DE, Dally GY, Ackerley CA, Weitz JI, Ray PN. Identification of Dp71 isoforms in the platelet membrane cytoskeleton. Potential role in thrombin-mediated platelet adhesion. J Biol Chem 2002; 277:47106-13. [PMID: 12370193 DOI: 10.1074/jbc.m203289200] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Utrophin is a component of the platelet membrane cytoskeleton and participates in cytoskeletal reorganization (Earnest, J. P., Santos, G. F., Zuerbig, S., and Fox, J. E. B. (1995) J. Biol. Chem. 270, 27259-27265). Although platelets do not contain dystrophin, the identification of smaller C-terminal isoforms of dystrophin, including Dp71, which are expressed in a wide range of nonmuscle tissues and cell lines, has not been investigated. In this report, we have identified Dp71 protein variants of 55-60 kDa (designated Dp71Delta(110)) in the membrane cytoskeleton of human platelets. Both Dp71Delta(110) and utrophin sediment from lysed platelets along with the high speed detergent-insoluble pellet, which contains components of the membrane cytoskeleton. Like the membrane cytoskeletal proteins vinculin and spectrin, Dp71Delta(110) and utrophin redistributed from the high speed detergent-insoluble pellet to the integrin-rich low speed pellet of thrombin-stimulated platelets. Immunoelectron microscopy provided further evidence that Dp71Delta(110) was localized to the submembranous cytoskeleton. In addition to Dp71Delta(110), platelets contained several components of the dystrophin-associated protein complex, including beta-dystroglycan and syntrophin. To better understand the potential function of Dp71Delta(110), collagen adhesion assays were performed on platelets isolated from wild-type or Dp71-deficient (mdx(3cv)) mice. Adhesion to collagen in response to thrombin was significantly decreased in platelets isolated from mdx(3cv) mice, compared with wild-type platelets. Collectively, our results provide evidence that Dp71Delta(110) is a component of the platelet membrane cytoskeleton, is involved in cytoskeletal reorganization and/or signaling, and plays a role in thrombin-mediated platelet adhesion.
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Affiliation(s)
- Richard C Austin
- Department of Pathology, McMaster University and the Henderson Research Centre, Hamilton, Ontario L8V 1C3, Canada.
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47
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Hosaka Y, Yokota T, Miyagoe-Suzuki Y, Yuasa K, Imamura M, Matsuda R, Ikemoto T, Kameya S, Takeda S. Alpha1-syntrophin-deficient skeletal muscle exhibits hypertrophy and aberrant formation of neuromuscular junctions during regeneration. J Cell Biol 2002; 158:1097-107. [PMID: 12221071 PMCID: PMC2173222 DOI: 10.1083/jcb.200204076] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Alpha1-syntrophin is a member of the family of dystrophin-associated proteins; it has been shown to recruit neuronal nitric oxide synthase and the water channel aquaporin-4 to the sarcolemma by its PSD-95/SAP-90, Discs-large, ZO-1 homologous domain. To examine the role of alpha1-syntrophin in muscle regeneration, we injected cardiotoxin into the tibialis anterior muscles of alpha1-syntrophin-null (alpha1syn-/-) mice. After the treatment, alpha1syn-/- muscles displayed remarkable hypertrophy and extensive fiber splitting compared with wild-type regenerating muscles, although the untreated muscles of the mutant mice showed no gross histological change. In the hypertrophied muscles of the mutant mice, the level of insulin-like growth factor-1 transcripts was highly elevated. Interestingly, in an early stage of the regeneration process, alpha1syn-/- mice showed remarkably deranged neuromuscular junctions (NMJs), accompanied by impaired ability to exercise. The contractile forces were reduced in alpha1syn-/- regenerating muscles. Our results suggest that the lack of alpha1-syntrophin might be responsible in part for the muscle hypertrophy, abnormal synapse formation at NMJs, and reduced force generation during regeneration of dystrophin-deficient muscle, all of which are typically observed in the early stages of Duchenne muscular dystrophy patients.
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Affiliation(s)
- Yukio Hosaka
- Department of Molecular Therapy, National Institute of Neuroscience, National Center of Neurology and Psychiatry, 4-1-1 Ogawa-higashi, Kodaira 187-8502, Tokyo, Japan
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48
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Grisoni K, Martin E, Gieseler K, Mariol MC, Ségalat L. Genetic evidence for a dystrophin-glycoprotein complex (DGC) in Caenorhabditis elegans. Gene 2002; 294:77-86. [PMID: 12234669 DOI: 10.1016/s0378-1119(02)00762-x] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Dystrophin is the product of the gene mutated in Duchenne muscular dystrophy (DMD). Neither the function of dystrophin nor the physiopathology of the disease have been clearly established so far. In mammals, the dystrophin-glycoprotein complex (DGC) includes dystrophin, as well as transmembrane and cytoplasmic proteins. Since Caenorhabditis elegans possesses a dystrophin-like gene (dys-1), we investigated whether homologues of the DGC members could also be found in the C. elegans genome. Conserved homologues were found for dystroglycan, delta/gamma-sarcoglycan and syntrophin. Divergent but related proteins were found for alpha- and beta-sarcoglycans. No sarcospan counterpart was found. The expression of the conserved homologues was inactivated using the RNA interference technique. Phenotypes similar to that of dys-1 were obtained, both in the wild-type background and in combination with other mutations. These results strongly suggest that a protein complex comprising functional analogies with the DGC exists in C. elegans.
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Affiliation(s)
- Karine Grisoni
- CGMC, CNRS-UMR 5534, Université Lyon-1, 43 boulevard du 11 Novembre, 69100 Cedex, Villeurbanne, France
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49
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Mishima A, Suzuki A, Enaka M, Hirose T, Mizuno K, Ohnishi T, Mohri H, Ishigatsubo Y, Ohno S. Over-expression of PAR-3 suppresses contact-mediated inhibition of cell migration in MDCK cells. Genes Cells 2002; 7:581-96. [PMID: 12059961 DOI: 10.1046/j.1365-2443.2002.00540.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
BACKGROUND PAR-3 is one of the PAR proteins, previously named ASIP, which are indispensable for the establishment of cell polarity in the embryo as well as differentiated epithelial cells. In mammalian epithelial cells, it forms a ternary complex with aPKC and PAR-6, and is localized to the tight junction that has been suggested as being important for creating cell polarity. RESULTS To gain insights into the mode of PAR-3 function in mammalian epithelial cells, we examined the effect of PAR-3 over-expression in MDCK cells. Although exogenous PAR-3-expression does not affect the epithelial polarity of confluent cells, it drastically transforms the morphology of cells at low density into a fibroblastic form with developed membrane protrusions. Time-lapse observations have revealed that PAR-3 over-expressing cells show intense motility, even after they have assembled into loose colonies, suggesting that the contact-mediated inhibition of cell migration (CIM) is suppressed. The expressions of E-cadherin and vimentin do not change with PAR-3 over-expression, suggesting that exogenous PAR-3 only disturbs the endogenous equilibrium of cellular states between a fundamental fibroblastic structure and an epithelial one. The co-expression of a dominant negative mutant of Rac1 and the addition of nocodazole strongly antagonize the effect of PAR-3 over-expression, suggesting the involvement of Rac1 activation and microtubule polymerizations. CONCLUSIONS : The data presented here suggest an intriguing link between the contact-mediated inhibition of cell migration and the regulation of cell polarity. The putative PAR-3 activities demonstrated here may function endogenously in the epithelial cell polarization process by being sequestered from the cytosol to the cell-cell junctional regions with aPKC and PAR-6 upon cell-cell adhesion.
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Affiliation(s)
- Aki Mishima
- Department of Molecular Biology, Yokohama City University School of Medicine, 3-9 Fuku-ura, Kanazawa-ku, Yokohama 236-0004, Japan
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50
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Hoshino S, Ohkoshi N, Ishii A, Kameya S, Takeda S, Shoji S. The expression of dystrophin and alpha1-syntrophin during skeletal muscle regeneration. J Muscle Res Cell Motil 2002; 22:185-91. [PMID: 11519741 DOI: 10.1023/a:1010553104341] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
The expression of dystrophin and alpha1-syntrophin in rat tibialis anterior muscles were evaluated during a cycle of regeneration after myonecrosis induced by the injection of cardiotoxin. Immunohistochemical studies were performed in cryosections of muscles on days 1, 3, 5, 7, 10, 14, 21 and 28 after injection of cardiotoxin. Western blot analysis was also examined in muscle on days 1, 3, 5, 7, 10, 14, 21 and 28. In immunohistochemical studies, dystrophin was stained weakly at the sarcolemma of some regenerating muscle fibers on day 3, and by day 10 it was stained strongly on almost all regenerating muscle fibers. Alpha1-syntrophin was stained weakly at the sarcolemma of some regenerating fibers on day 5, and by day 14 it was detected on all regenerating muscle fibers. In Western blot analysis, dystrophin (DYS1) and alpha1-syntrophin (alpha1S) were completely absent on day 1. Re-expression of DYS1 and alpha1S was visible by day 5 and accelerated thereafter. The Western blots of DYS1 and alpha1S were densitometrically analyzed on each day. The protein levels on each day were converted to the percentage of the protein level on day 28, which was taken as 100%. From the sequential line based on these data, the following results were obtained on the chronological course of DYS1 and alpha1S. DYS1: 25% of the protein level on day 28 was reached by 3.5 days, 50% was reached by 5.3 days, and 90% was reached by 6.9 days. Alpha1S: 25% of the protein level on day 28 was reached by 4.6 days, 50% was reached by 6.0 days, and 90% was reached by 12.5 days. In this study, DYS1 regenerated earlier than alpha1S at the sarcolemma of regenerating muscle fibers.
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Affiliation(s)
- S Hoshino
- Department of Neurology, Institute of Clinical Medicine, University of Tsukuba, Japan
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