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Barboni MTS, Joachimsthaler A, Roux MJ, Nagy ZZ, Ventura DF, Rendon A, Kremers J, Vaillend C. Retinal dystrophins and the retinopathy of Duchenne muscular dystrophy. Prog Retin Eye Res 2022:101137. [DOI: 10.1016/j.preteyeres.2022.101137] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2022] [Revised: 10/25/2022] [Accepted: 11/03/2022] [Indexed: 11/21/2022]
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2
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Ohno S, Saitoh Y, Ohno N, Terada N. Renaissance of morphological studies: the examination of functional structures in living animal organs using the in vivo cryotechnique. Anat Sci Int 2016; 92:55-78. [DOI: 10.1007/s12565-016-0355-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2016] [Accepted: 06/27/2016] [Indexed: 11/28/2022]
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3
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Gingras J, Gawor M, Bernadzki KM, Grady RM, Hallock P, Glass DJ, Sanes JR, Proszynski TJ. Α-Dystrobrevin-1 recruits Grb2 and α-catulin to organize neurotransmitter receptors at the neuromuscular junction. J Cell Sci 2016; 129:898-911. [PMID: 26769899 DOI: 10.1242/jcs.181180] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2015] [Accepted: 01/11/2016] [Indexed: 12/17/2022] Open
Abstract
Neuromuscular junctions (NMJs), the synapses made by motor neurons on muscle fibers, form during embryonic development but undergo substantial remodeling postnatally. Several lines of evidence suggest that α-dystrobrevin, a component of the dystrophin-associated glycoprotein complex (DGC), is a crucial regulator of the remodeling process and that tyrosine phosphorylation of one isoform, α-dystrobrevin-1, is required for its function at synapses. We identified a functionally important phosphorylation site on α-dystrobrevin-1, generated phosphorylation-specific antibodies to it and used them to demonstrate dramatic increases in phosphorylation during the remodeling period, as well as in nerve-dependent regulation in adults. We then identified proteins that bind to this site in a phosphorylation-dependent manner and others that bind to α-dystrobrevin-1 in a phosphorylation-independent manner. They include multiple members of the DGC, as well as α-catulin, liprin-α1, Usp9x, PI3K, Arhgef5 and Grb2. Finally, we show that two interactors, α-catulin (phosphorylation independent) and Grb2 (phosphorylation dependent) are localized to NMJs in vivo, and that they are required for proper organization of neurotransmitter receptors on myotubes.
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Affiliation(s)
- Jacinthe Gingras
- Department of Molecular and Cellular Biology and Center for Brain Science, Harvard University, Cambridge, MA 02138, USA
| | - Marta Gawor
- Laboratory of Synaptogenesis, Dept. of Cell Biology, Nencki Institute of Experimental Biology, Warsaw 02-093, Poland
| | - Krzysztof M Bernadzki
- Laboratory of Synaptogenesis, Dept. of Cell Biology, Nencki Institute of Experimental Biology, Warsaw 02-093, Poland
| | - R Mark Grady
- Department of Anatomy and Neurobiology, Washington University School of Medicine, St Louis, MO 63110, USA
| | - Peter Hallock
- Novartis Biomedical Institute, Cambridge, MA 02139, USA
| | - David J Glass
- Novartis Biomedical Institute, Cambridge, MA 02139, USA
| | - Joshua R Sanes
- Department of Molecular and Cellular Biology and Center for Brain Science, Harvard University, Cambridge, MA 02138, USA Department of Anatomy and Neurobiology, Washington University School of Medicine, St Louis, MO 63110, USA
| | - Tomasz J Proszynski
- Laboratory of Synaptogenesis, Dept. of Cell Biology, Nencki Institute of Experimental Biology, Warsaw 02-093, Poland
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4
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Kakarla SK, Rice KM, Katta A, Paturi S, Wu M, Kolli M, Keshavarzian S, Manzoor K, Wehner PS, Blough ER. Possible molecular mechanisms underlying age-related cardiomyocyte apoptosis in the F344XBN rat heart. J Gerontol A Biol Sci Med Sci 2010; 65:147-55. [PMID: 20056683 DOI: 10.1093/gerona/glp203] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Despite advances in treatment, age-related cardiac dysfunction still remains a leading cause of cardiovascular death. Recent data have suggested that increases in cardiomyocyte apoptosis may be involved in the pathological remodeling of heart. Here, we examine the effects of aging on cardiomyocyte apoptosis in 6-, 30-, and 36-month-old Fischer344 x Brown Norway F1 hybrid rats (F344XBN). Compared with 6-month hearts, aged hearts exhibited increased TdT-mediated dUTP nick end labeling-positive nuclei, caspase-3 activation, caspase-dependent cleavage of alpha-fodrin and diminished phosphorylation of protein kinase B/Akt (Thr 308). These age-dependent increases in cardiomyocyte apoptosis were associated with alterations in the composition of the cardiac dystrophin glycoprotein complex and elevated cytoplasmic IgG and albumin immunoreactivity. Immunohistochemical analysis confirmed these data and demonstrated qualitative differences in localization of dystrophin-glycoprotein complex (DGC) molecules with aging. Taken together, these data suggest that aging-related increases in cardiac apoptotic activity model may be due, at least in part, to age-associated changes in DGC structure.
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Affiliation(s)
- Sunil K Kakarla
- Laboratory of Molecular Physiology, Robert C. Byrd Biotechnology Science Center, Department of Biological Sciences, 1700 3rd Avenue, Marshall University, Huntington, WV 25755-1090, USA
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5
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Houlden H, Charlton P, Singh D. Neurology and orthopaedics. J Neurol Neurosurg Psychiatry 2007; 78:224-32. [PMID: 17308288 PMCID: PMC2117631 DOI: 10.1136/jnnp.2006.092072] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/09/2006] [Revised: 03/09/2006] [Accepted: 11/02/2006] [Indexed: 01/07/2023]
Abstract
Neurology encompasses all aspects of medicine and surgery, but is closer to orthopaedic surgery than many other specialities. Both neurological deficits and bone disorders lead to locomotor system abnormalities, joint complications and limb problems. The main neurological conditions that require the attention of an orthopaedic surgeon are disorders that affect the lower motor neurones. The most common disorders in this group include neuromuscular disorders and traumatic peripheral nerve lesions. Upper motor neurone disorders such as cerebral palsy and stroke are also frequently seen and discussed, as are chronic conditions such as poliomyelitis. The management of these neurological problems is often coordinated in the neurology clinic, and this group, probably more than any other, requires a multidisciplinary team approach.
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Affiliation(s)
- Henry Houlden
- Centre for Neuromuscular Disease and Department of Molecular Neurosciences, The National Hospital for Neurology and Neurosurgery, Queen Square, London WC1N 3BG, UK.
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6
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Rice KM, Preston DL, Neff D, Norton M, Blough ER. Age-Related Dystrophin-Glycoprotein Complex Structure and Function in the Rat Extensor Digitorum Longus and Soleus Muscle. J Gerontol A Biol Sci Med Sci 2006; 61:1119-29. [PMID: 17167152 DOI: 10.1093/gerona/61.11.1119] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
This study tested the hypothesis that age-related changes in the dystrophin-glycoprotein complex (DGC) may precede age-associated alterations in muscle morphology and function. Compared to those in adult (6 month) rats, extensor digitorum longus (EDL) and soleus muscle mass was decreased in old (30 month) and very old (36 month) Fischer 344/NNiaHSD x Brown Norway/BiNia rats. The amount of dystrophin, beta-dystroglycan, and alpha-sarcoglycan increased with aging in the EDL and decreased with aging in the soleus. alpha-Dystroglycan levels were increased with aging in both muscles and displayed evidence of altered glycosylation. Immunostaining for the presence of antibody infiltration and dystrophin following increased muscle stretch suggested that the aging in the soleus was characterized by diminished membrane integrity. Together, these data suggest that aging is associated with alterations in EDL and soleus DGC protein content and localization. These results may implicate the DGC as playing a role in age-associated skeletal muscle remodeling.
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Affiliation(s)
- Kevin M Rice
- Laboratory of Molecular Physiology, Suite 311, Science Building, Department of Biological Sciences, 1 John Marshall Drive, Marshall University, Huntington, WV 25755-1090, USA
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7
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Assadi M, Müntener M. Utrophin is lacking at the neuromuscular junctions in the extraocular muscles of normal cat: artefact or true? Histochem Cell Biol 2005; 123:189-94. [PMID: 15729554 DOI: 10.1007/s00418-005-0762-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/13/2004] [Indexed: 10/25/2022]
Abstract
Extraocular muscles (EOM) are typically spared in Duchenne muscular dystrophy. We hypothesized that this might be due to different patterns of utrophin expression. The expression of utrophin was examined in EOM of normal cats using immunohistochemical methods and Western blot. For detecting acetylcholine receptors (AChR), we used alpha-bungarotoxin. Surprisingly, alpha-bungarotoxin failed to stain the AChR and no expression of utrophin could be detected at the neuromuscular junctions. Our study could indicate that the expression of utrophin is dependent on the structure of the AChR.
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Affiliation(s)
- Maziar Assadi
- Institute of Anatomy, University of Zürich-Irchel, Zürich, Switzerland.
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8
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Shishkin SS, Kovalyov LI, Kovalyova MA. Proteomic studies of human and other vertebrate muscle proteins. BIOCHEMISTRY (MOSCOW) 2004; 69:1283-98. [PMID: 15627382 DOI: 10.1007/s10541-005-0074-7] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
This review summarizes results of some systemic studies of muscle proteins of humans and some other vertebrates. The studies, started after introduction of two-dimensional gel electrophoresis of O'Farrell, were significantly extended during development of proteomics, a special branch of functional genomics. Special attention is paid to analysis of characteristic features of strategy for practical realization of the systemic approach during three main stages of these studies: pre-genomic, genomic (with organizational registration of proteomics), and post-genomic characterized by active use of structural genomics data. Proteomic technologies play an important role in detection of changes in isoforms of various muscle proteins (myosins, troponins, etc.). These changes possibly reflecting tissue specificity of gene expression may underline functional state of muscle tissues under normal and pathological conditions, and such proteomic analysis is now used in various fields of medicine.
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Affiliation(s)
- S S Shishkin
- Bach Institute of Biochemistry, Russian Academy of Sciences, Moscow 119071, Russia.
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9
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Proteomic studies of human and other vertebrate muscle proteins. BIOCHEMISTRY (MOSCOW) 2004. [DOI: 10.1007/pl00021771] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/09/2023]
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10
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Kulyte A, Navakauskiene R, Treigyte G, Gineitis A, Bergman T, Magnusson KE. Characterization of human alpha-dystrobrevin isoforms in HL-60 human promyelocytic leukemia cells undergoing granulocytic differentiation. Mol Biol Cell 2002; 13:4195-205. [PMID: 12475945 PMCID: PMC138626 DOI: 10.1091/mbc.e02-03-0128] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2002] [Revised: 07/30/2002] [Accepted: 09/09/2002] [Indexed: 11/11/2022] Open
Abstract
The biochemical properties and spatial localization of the protein alpha-dystrobrevin and other isoforms were investigated in cells of the human promyelocytic leukemia line HL-60 granulocytic differentiation as induced by retinoic acid (RA). Alpha-dystrobrevin was detected both in the cytosol and the nuclei of these cells, and a short isoform (gamma-dystrobrevin) was modified by tyrosine phosphorylation soon after the onset of the RA-triggered differentiation. Varying patterns of distribution of alpha-dystrobrevin and its isoforms could be discerned in HL-60 promyelocytes, RA-differentiated mature granulocytes, and human neutrophils. Moreover, the gamma-dystrobrevin isoform was found in association with actin and myosin light chain. The results provide new information about potential involvement of alpha-dystrobrevin and its splice isoforms in signal transduction in myeloid cells during induction of granulocytic differentiation and/or at the commitment stage of differentiation or phagocytic cells.
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Affiliation(s)
- Agné Kulyte
- Division of Medical Microbiology, Linköpings Universitet, SE-581 85 Linköping, Sweden.
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11
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Kilmer DD. Response to resistive strengthening exercise training in humans with neuromuscular disease. Am J Phys Med Rehabil 2002; 81:S121-6. [PMID: 12409817 DOI: 10.1097/00002060-200211001-00013] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
The role of strengthening exercise to potentially improve weakness and the functional abilities of persons with neuromuscular diseases is controversial. There are questions about the ability of diseased skeletal muscle to respond to resistance exercise, particularly in light of concerns about weakness induced by exercise. Numerous studies show promising results of strength training, although methodologic issues limit conclusions. This article reviews current knowledge in this area and provides recommendations for future investigations.
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Affiliation(s)
- David D Kilmer
- Department of Physical Medicine and Rehabilitation, University of California-Davis School of Medicine, Sacramento, California, USA
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12
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Blank M, Blake DJ, Kröger S. Molecular diversity of the dystrophin-like protein complex in the developing and adult avian retina. Neuroscience 2002; 111:259-73. [PMID: 11983313 DOI: 10.1016/s0306-4522(02)00032-5] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Mutations in dystrophin cause muscular dystrophy but also affect the CNS, including information processing in the retina. To better understand the molecular basis of these CNS deficits, we analyzed the molecular composition and developmental appearance of dystrophin and of the dystrophin-associated protein complex (DPC) in the embryonic and adult avian retina. We detected a concentration of the DPC at the vitreal border and in the outer plexiform layer of the adult retina. At both locations the complex had a different molecular composition and different developmental expression pattern. At the vitreal border, the complex was composed of utrophin, alpha-dystrobrevin-1, and dystroglycan, and was present at all stages of retinal development even before neurogenesis and gliogenesis. On the other hand, the complex in the outer plexiform layer consisted of dystrophin, beta-dystrobrevin and dystroglycan. The distribution of this complex changed from a diffusely distributed to an aggregated form during development concomitant with synapse formation in the outer plexiform layer. Solubilization of the retinal extracellular matrix by intravitreal injection of collagenase resulted in a redistribution of the complex at the retinal vitreal border but had no influence on the distribution of the dystrophin-associated proteins in the outer plexiform layer. These results demonstrate two types of dystrophin-like complexes in the chick retina with differential molecular compositions, different anchorage to the extracellular matrix, and different developmental expression patterns, suggesting distinct functions for the DPC at both locations.
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Affiliation(s)
- M Blank
- Department of Neuroanatomy, Max-Planck-Institute for Brain Research, Deutschordenstrasse 46, Frankfurt, Germany
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13
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Kapiloff MS. Contributions of protein kinase A anchoring proteins to compartmentation of cAMP signaling in the heart. Mol Pharmacol 2002; 62:193-9. [PMID: 12130668 DOI: 10.1124/mol.62.2.193] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
The cAMP-dependent protein kinase (PKA) transduces signals in the heart initiated by beta(1)-adrenergic, G-protein-coupled receptors after norepinephrine, sympathetic stimulation. Signaling through this pathway results in a characteristic set of cellular responses, including increases in ion fluxes and contractile strength, mobilization of energy stores, and changes in gene expression. Not all receptors that activate adenylate cyclase and increase cAMP levels, however, cause the cardiac myocyte to react in this manner. Research in the field of signal transduction over the last 25 years has addressed this issue of specificity in signaling by diffusable second messengers. PKA is in part targeted to discrete cellular locations by A-kinase anchoring proteins. Through anchoring and formation of multienzyme complexes, specific, localized signal transduction is possible. I discuss in this review recent advances in the understanding of PKA signaling complexes in the cardiac myocyte.
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Affiliation(s)
- Michael S Kapiloff
- Department of Pediatrics, Heart Research Center, Oregon Health and Science University, Portland, Oregon 97201, USA.
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14
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Biggar WD, Klamut HJ, Demacio PC, Stevens DJ, Ray PN. Duchenne muscular dystrophy: current knowledge, treatment, and future prospects. Clin Orthop Relat Res 2002:88-106. [PMID: 12151886 DOI: 10.1097/00003086-200208000-00012] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The cloning of the dystrophin gene has led to major advances in the understanding of the molecular genetic basis of Duchenne, Becker, and other muscular dystrophies associated with mutations in genes encoding members of the dystrophin-associated glycoprotein complex. The recent introduction of pharmaceutical agents such as prednisone has shown great promise in delaying the progression of Duchenne muscular dystrophy but there remains a need to develop more long-term therapeutic interventions. Knowledge of the nature of the dystrophin gene and the glycoprotein complex has led many researchers to think that somatic gene replacement represents the most promising approach to treatment. The potential use of this strategy has been shown in the mdx mouse model of Duchenne muscular dystrophy, where germ line gene transfer of either a full-length or a smaller Becker-type dystrophin minigene prevents necrosis and restores normal muscle function.
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Affiliation(s)
- W Douglas Biggar
- Bloorview MacMillan Children's Centre and Department of Paediatrics, University of Toronto, Ontario, Canada
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15
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Leriche-Guérin K, Anderson LVB, Wrogemann K, Roy B, Goulet M, Tremblay JP. Dysferlin expression after normal myoblast transplantation in SCID and in SJL mice. Neuromuscul Disord 2002; 12:167-73. [PMID: 11738359 DOI: 10.1016/s0960-8966(01)00254-1] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Limb girdle muscular dystrophy type 2B form and Miyoshi myopathy are both caused by mutations in the recently cloned gene dysferlin. In the present study, we have investigated whether cell transplantation could permit dysferlin expression in vivo. Two transplantation models were used: SCID mice transplanted with normal human myoblasts, and SJL mice, the mouse model for limb girdle muscular dystrophy type 2B and Miyoshi myopathy, transplanted with allogeneic primary mouse muscle cell cultures expressing the beta-galactosidase gene under control of a muscle promoter of Troponin I. FK506 immunosuppression was used in the non-compatible allogeneic model. One month after transplantation, human and mouse dysferlin proteins were detected in all transplanted SCID and SJL muscles, respectively. Co-localization of dysferlin and human dystrophin or beta-galactosidase-positive fibers was observed following the transplantation of myoblasts. Dysferlin proteins were monitored by immunocytochemistry and Western blot. The number of dysferlin-positive fibers was 40-50% and 20-30% in SCID and SJL muscle sections, respectively. Detection of dysferlin in both SCID mice and dysferlin-deficient SJL mouse shows that myoblast transplantation permits the expression of the donor dysferlin protein.
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MESH Headings
- Amino Acid Sequence
- Animals
- Blotting, Western
- Cell Transplantation
- Cells, Cultured
- Disease Models, Animal
- Dysferlin
- Gene Expression Regulation
- Genetic Therapy
- Membrane Proteins
- Mice
- Mice, Mutant Strains
- Mice, SCID
- Molecular Sequence Data
- Muscle Fibers, Skeletal/physiology
- Muscle Proteins/chemistry
- Muscle Proteins/deficiency
- Muscle Proteins/genetics
- Muscle, Skeletal/cytology
- Muscle, Skeletal/enzymology
- Muscle, Skeletal/transplantation
- Muscular Dystrophies/genetics
- Muscular Dystrophies/therapy
- Mutation
- Peptide Fragments
- Promoter Regions, Genetic
- Transplantation, Heterologous
- Transplantation, Homologous
- Troponin I/genetics
- beta-Galactosidase/genetics
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Affiliation(s)
- K Leriche-Guérin
- Unité de recherche en Génétique humaine, Centre de Recherche du Centre Hospitalier de l'Université Laval, CHUL du CHUQ, Ste-Foy, QC, Canada
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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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17
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Kilmer DD, Aitkens SG, Wright NC, McCrory MA. Response to high-intensity eccentric muscle contractions in persons with myopathic disease. Muscle Nerve 2001; 24:1181-7. [PMID: 11494271 DOI: 10.1002/mus.1130] [Citation(s) in RCA: 24] [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]
Abstract
Although the response to intense eccentric muscle contractions is well described in normal subjects, concern exists about possible untoward effects in persons with myopathic diseases. We investigated 14 subjects with slowly progressive muscular dystrophies including myotonic muscular dystrophy (n = 9), facioscapulohumeral dystrophy (n = 2), limb-girdle syndrome (n = 2), and Becker muscular dystrophy (n = 1). Control subjects consisted of 18 able-bodied persons. Subjects performed two sets of eight maximal-effort eccentric repetitions of the elbow flexors, with measurement of maximal concentric strength, serum creatine kinase, resting and flexed arm angle, arm circumference, and soreness at days 0, 3, and 7. Although the myopathic group had less initial strength, both groups demonstrated a similar response to the protocol over 7 days. Both groups had a significant rise in serum creatine kinase, which was still elevated at 7 days (P < 0.05). The control group demonstrated a slightly greater injury response in terms of soreness, resting and flexed arm angles, and arm swelling. Both groups of subjects appeared to respond similarly to an acute bout of eccentric contractions. However, the potential long-term effects of this type of exercise in persons with myopathic diseases remains unknown.
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Affiliation(s)
- D D Kilmer
- Department of Physical Medicine and Rehabilitation, School of Medicine, University of California, Davis, California, USA.
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18
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Cowan WM, Harter DH, Kandel ER. The emergence of modern neuroscience: some implications for neurology and psychiatry. Annu Rev Neurosci 2000; 23:343-91. [PMID: 10845068 DOI: 10.1146/annurev.neuro.23.1.343] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
One of the most significant developments in biology in the past half century was the emergence, in the late 1950s and early 1960s, of neuroscience as a distinct discipline. We review here factors that led to the convergence into a common discipline of the traditional fields of neurophysiology, neuroanatomy, neurochemistry, and behavior, and we emphasize the seminal roles played by David McKenzie Rioch, Francis O Schmitt, and especially Stephen W Kuffler in creating neuroscience as we now know it. The application of the techniques of molecular and cellular biology to the study of the nervous system has greatly accelerated our understanding of the mechanisms involved in neuronal signaling, neural development, and the function of the major sensory and motor systems of the brain. The elucidation of the underlying causes of most neurological and psychiatric disorders has proved to be more difficult; but striking progress is now being made in determining the genetic basis of such disorders as Alzheimer's disease, amyotrophic lateral sclerosis, Parkinson's disease, and a number of ion channel and mitochondrial disorders, and a significant start has been made in identifying genetic factors in the etiology of such disorders as manic depressive illness and schizophrenia. These developments presage the emergence in the coming decades of a new nosology, certainly in neurology and perhaps also in psychiatry, based not on symptomatology but on the dysfunction of specific genes, molecules, neuronal organelles and particular neural systems.
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Affiliation(s)
- W M Cowan
- Howard Hughes Medical Institute, Chevy Chase, Maryland 20815, USA
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19
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Mehler MF. Brain dystrophin, neurogenetics and mental retardation. BRAIN RESEARCH. BRAIN RESEARCH REVIEWS 2000; 32:277-307. [PMID: 10751678 DOI: 10.1016/s0165-0173(99)00090-9] [Citation(s) in RCA: 134] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Duchenne muscular dystrophy (DMD) and the allelic disorder Becker muscular dystrophy (BMD) are common X-linked recessive neuromuscular disorders that are associated with a spectrum of genetically based developmental cognitive and behavioral disabilities. Seven promoters scattered throughout the huge DMD/BMD gene locus normally code for distinct isoforms of the gene product, dystrophin, that exhibit nervous system developmental, regional and cell-type specificity. Dystrophin is a complex plasmalemmal-cytoskeletal linker protein that possesses multiple functional domains, autosomal and X-linked homologs and associated binding proteins that form multiunit signaling complexes whose composition is unique to each cellular and developmental context. Through additional interactions with a variety of proteins of the extracellular matrix, plasma membrane, cytoskeleton and distinct intracellular compartments, brain dystrophin acquires the capability to participate in the modulatory actions of a large number of cellular signaling pathways. During neural development, dystrophin is expressed within the neural tube and selected areas of the embryonic and postnatal neuraxis, and may regulate distinct aspects of neurogenesis, neuronal migration and cellular differentiation. By contrast, in the mature brain, dystrophin is preferentially expressed by specific regional neuronal subpopulations within proximal somadendritic microdomains associated with synaptic terminal membranes. Increasing experimental evidence suggests that in adult life, dystrophin normally modulates synaptic terminal integrity, distinct forms of synaptic plasticity and regional cellular signal integration. At a systems level, dystrophin may regulate essential components of an integrated sensorimotor attentional network. Dystrophin deficiency in DMD/BMD patients and in the mdx mouse model appears to impair intracellular calcium homeostasis and to disrupt multiple protein-protein interactions that normally promote information transfer and signal integration from the extracellular environment to the nucleus within regulated microdomains. In DMD/BMD, the individual profiles of cognitive and behavioral deficits, mental retardation and other phenotypic variations appear to depend on complex profiles of transcriptional regulation associated with individual dystrophin mutations that result in the corresponding presence or absence of individual brain dystrophin isoforms that normally exhibit developmental, regional and cell-type-specific expression and functional regulation. This composite experimental model will allow fine-level mapping of cognitive-neurogenetic associations that encompass the interrelationships between molecular, cellular and systems levels of signal integration, and will further our understanding of complex gene-environmental interactions and the pathogenetic basis of developmental disorders associated with mental retardation.
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Affiliation(s)
- M F Mehler
- Departments of Neurology, Neuroscience and Psychiatry, the Einstein Comprehensive Cancer Center, Albert Einstein College of Medicine, Bronx, NY 10461, USA.
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Lin S, Burgunder JM. Utrophin may be a precursor of dystrophin during skeletal muscle development. BRAIN RESEARCH. DEVELOPMENTAL BRAIN RESEARCH 2000; 119:289-95. [PMID: 10675780 DOI: 10.1016/s0165-3806(99)00165-0] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Expression patterns of utrophin were investigated and compared to those of dystrophin and associated proteins in skeletal muscle of rat embryos from E12 to E21 by immunohistochemistry. Utrophin was readily detected from E12 on, earlier than full-length dystrophin on E14. A shorter dystrophin isoform was observed from E12 to E16. The level of utrophin reached a maximum on E16-17 and then declined while that of dystrophin increased after E17. A complementary distribution of these two molecules was observed on E18. Beta-dystroglycan appeared as early as utrophin. Sarcoglycans, appearing from E14 on, were anchored first by utrophin and then by dystrophin. These results elucidate the chronological order of expression of the dytrophin/utrophin protein complex and indicate that this protein complex is originally stabilized by utrophin. This study supports our hypothesis that utrophin might be a developmental precursor of dystrophin.
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Affiliation(s)
- S Lin
- Laboratory of Neuromorphology, Department of Neurology, Inselspital/University Hospital of Berne, CH-3010, Berne, Switzerland
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21
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Kapiloff MS, Schillace RV, Westphal AM, Scott JD. mAKAP: an A-kinase anchoring protein targeted to the nuclear membrane of differentiated myocytes. J Cell Sci 1999; 112 ( Pt 16):2725-36. [PMID: 10413680 DOI: 10.1242/jcs.112.16.2725] [Citation(s) in RCA: 134] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The compartmentalization of second messenger-activated protein kinases contributes to the fidelity of hormone-mediated signal transduction events. For example, the cAMP-dependent protein kinase is tethered at specific intracellular locations through association with A-kinase anchoring proteins (AKAPs). We now report the cloning of mAKAP, an anchoring protein found predominantly in heart, skeletal muscle and brain, and whose expression is induced in neonatal ventriculocytes by treatment with hypertrophic stimuli. mAKAP is targeted to the nuclear membrane of differentiated myocytes. Analysis of mAKAP-green fluorescent protein (GFP) fusion constructs revealed that nuclear membrane targeting is conferred by two regions of the protein, between residues 772–915 and 915–1065, which contain spectrin-like repeat sequences. Heterologous expression of the mAKAP targeting sequences displaced the endogenous anchoring protein from the nuclear membrane, demonstrating that mAKAP targeting is saturable. Collectively, these data suggest that a domain containing spectrin-like repeats mediates targeting of the anchoring protein mAKAP and the cAMP-dependent protein kinase holoenzyme to the nuclear membrane in response to differentiation signals.
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MESH Headings
- A Kinase Anchor Proteins
- Adaptor Proteins, Signal Transducing
- Animals
- Animals, Newborn
- Antibodies
- Carrier Proteins/chemistry
- Carrier Proteins/genetics
- Carrier Proteins/metabolism
- Cell Differentiation/physiology
- Chromosome Mapping
- Cloning, Molecular
- Cyclic AMP-Dependent Protein Kinases/analysis
- Fluorescent Antibody Technique
- Gene Expression Regulation, Enzymologic
- Heart Ventricles/cytology
- Humans
- Microscopy, Confocal
- Molecular Sequence Data
- Muscle Fibers, Skeletal/chemistry
- Muscle Fibers, Skeletal/cytology
- Muscle Fibers, Skeletal/enzymology
- Mutagenesis/physiology
- Myocardium/chemistry
- Myocardium/cytology
- Myocardium/enzymology
- Nuclear Envelope/chemistry
- Nuclear Envelope/enzymology
- Peptide Fragments/analysis
- Peptide Fragments/immunology
- Protein Binding/physiology
- Protein Structure, Tertiary
- Rats
- Sequence Homology, Amino Acid
- Spectrin/analysis
- Spectrin/chemistry
- Spectrin/genetics
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Affiliation(s)
- M S Kapiloff
- Howard Hughes Medical Institute, L-474, Vollum Institute, Portland OR 97201-3098, USA
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22
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Khurana TS, Rosmarin AG, Shang J, Krag TO, Das S, Gammeltoft S. Activation of utrophin promoter by heregulin via the ets-related transcription factor complex GA-binding protein alpha/beta. Mol Biol Cell 1999; 10:2075-86. [PMID: 10359616 PMCID: PMC25417 DOI: 10.1091/mbc.10.6.2075] [Citation(s) in RCA: 89] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Utrophin/dystrophin-related protein is the autosomal homologue of the chromosome X-encoded dystrophin protein. In adult skeletal muscle, utrophin is highly enriched at the neuromuscular junction. However, the molecular mechanisms underlying regulation of utrophin gene expression are yet to be defined. Here we demonstrate that the growth factor heregulin increases de novo utrophin transcription in muscle cell cultures. Using mutant reporter constructs of the utrophin promoter, we define the N-box region of the promoter as critical for heregulin-mediated activation. Using this region of the utrophin promoter for DNA affinity purification, immunoblots, in vitro kinase assays, electrophoretic mobility shift assays, and in vitro expression in cultured muscle cells, we demonstrate that ets-related GA-binding protein alpha/beta transcription factors are activators of the utrophin promoter. Taken together, these results suggest that the GA-binding protein alpha/beta complex of transcription factors binds and activates the utrophin promoter in response to heregulin-activated extracellular signal-regulated kinase in muscle cell cultures. These findings suggest methods for achieving utrophin up-regulation in Duchenne's muscular dystrophy as well as mechanisms by which neurite-derived growth factors such as heregulin may influence the regulation of utrophin gene expression and subsequent enrichment at the neuromuscular junction of skeletal muscle.
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Affiliation(s)
- T S Khurana
- Department of Clinical Biochemistry, University of Copenhagen Medical School, The Glostrup Hospital, Glostrup DK 2600, Denmark.
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23
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Anderson LV, Davison K, Moss JA, Young C, Cullen MJ, Walsh J, Johnson MA, Bashir R, Britton S, Keers S, Argov Z, Mahjneh I, Fougerousse F, Beckmann JS, Bushby KM. Dysferlin is a plasma membrane protein and is expressed early in human development. Hum Mol Genet 1999; 8:855-61. [PMID: 10196375 DOI: 10.1093/hmg/8.5.855] [Citation(s) in RCA: 190] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Recently, a single gene, DYSF, has been identified which is mutated in patients with limb-girdle muscular dystrophy type 2B (LGMD2B) and with Miyoshi myopathy (MM). This is of interest because these diseases have been considered as two distinct clinical conditions since different muscle groups are the initial targets. Dysferlin, the protein product of the gene, is a novel molecule without homology to any known mammalian protein. We have now raised a monoclonal antibody to dysferlin and report on the expression of this new protein: immunolabelling with the antibody (designated NCL-hamlet) demonstrated a polypeptide of approximately 230 kDa on western blots of skeletal muscle, with localization to the muscle fibre membrane by microscopy at both the light and electron microscopic level. A specific loss of dysferlin labelling was observed in patients with mutations in the LGMD2B/MM gene. Furthermore, patients with two different frameshifting mutations demonstrated very low levels of immunoreactive protein in a manner reminiscent of the dystrophin expressed in many Duchenne patients. Analysis of human fetal tissue showed that dysferlin was expressed at the earliest stages of development examined, at Carnegie stage 15 or 16 (embryonic age 5-6 weeks). Dysferlin is present, therefore, at a time when the limbs start to show regional differentiation. Lack of dysferlin at this critical time may contribute to the pattern of muscle involvement that develops later, with the onset of a muscular dystrophy primarily affecting proximal or distal muscles.
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Affiliation(s)
- L V Anderson
- Neurobiology Department, University Medical School, Framlington Place, Newcastle upon Tyne NE2 4HH, UK.
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24
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Abstract
Most models of in vivo musculoskeletal function fail to take into account the diversity of force trajectories defined by muscle fiber architecture. It has been shown for many muscles, across species, that muscle fibers commonly end within muscle fascicles without reaching a myotendinous junction, and that many of these fibers show a progressive decline in cross-sectional area along the length of the muscle. The significance of these anatomical observations is that the tapering would seem to preclude forces generated at the largest cross-sectional area of the fibers being transmitted to the sarcomeres toward the ends of the tapered fiber. If all of the forces are transmitted via the sarcomeres arranged in series, those few sarcomeres at the smaller ends of the fibers must tolerate the stress exerted by the more numerous sarcomeres arranged in parallel at the portions of the fiber with larger cross-sectional areas. A logical alternative would be for forces to be transmitted laterally along the length of a fiber to the cell membrane and the extracellular matrix. Such a structural arrangement would permit an alternative force transmission vector and minimize the necessity for a precise level of force to be generated along the entire length of a fiber. There are cytoarchitectural and biochemical data demonstrating the presence of a subcellular network which is appropriately located to transmit forces from the active intracellular contractile elements to the extracellular intramuscular connective tissues. However, to fully comprehend how forces are transmitted from individual cross bridges to the tendon, it will be necessary to understand the interactions of all of the components of the muscle tendon complex from the molecular to the multicellular level. It is insufficient to know the physiology of the individual components in a restricted experimental paradigm and assume that these conditions account for the functional characteristics in vivo. Thus, the challenge is to understand how the sarcomeres and all of the associated structures transmit the forces of the whole muscle to its attachments.
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Affiliation(s)
- R J Monti
- Department of Physiological Science, University of California, Los Angeles 90095-1527, USA
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25
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Kawajiri M, Mitsui T, Kawai H, Shono M, Matsumoto T. Quantitative analysis of immunofluorescent signals for dystrophin, beta-dystroglycan and myosin skeletal muscle by epifluorescence microscopy. Biotech Histochem 1999; 74:92-7. [PMID: 10333406 DOI: 10.3109/10520299909066483] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Quantitative analysis of signal intensities in immunostained sections has been performed in only a few studies owing to difficulties with quantifying amounts of antigen present. We determined correlations between fluorescent signal intensities and amounts of antigen in muscle cryosections by altering section thickness from 4 to 10 microm. Fluorescent signals of dystrophin. beta-dystroglycan and myosin were detected with monoclonal and/or polyclonal primary antibodies using routine procedures. Confocal laser microscopy demonstrated that these signals were distributed uniformly along the z-axis suggesting that the antibodies permeated well through the sections. Epifluorescence microscopy with microfluorometry demonstrated a positive correlation between the optical density of signals and section thickness. These findings suggest that immunofluorescent signals can be quantitated by epifluorescence microscopy.
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Affiliation(s)
- M Kawajiri
- First Department of Internal Medicine, School of Medicine, University of Tokushima, Japan
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26
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Liu J, Aoki M, Illa I, Wu C, Fardeau M, Angelini C, Serrano C, Urtizberea JA, Hentati F, Hamida MB, Bohlega S, Culper EJ, Amato AA, Bossie K, Oeltjen J, Bejaoui K, McKenna-Yasek D, Hosler BA, Schurr E, Arahata K, de Jong PJ, Brown RH. Dysferlin, a novel skeletal muscle gene, is mutated in Miyoshi myopathy and limb girdle muscular dystrophy. Nat Genet 1998; 20:31-6. [PMID: 9731526 DOI: 10.1038/1682] [Citation(s) in RCA: 626] [Impact Index Per Article: 24.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Miyoshi myopathy (MM) is an adult onset, recessive inherited distal muscular dystrophy that we have mapped to human chromosome 2p13. We recently constructed a 3-Mb P1-derived artificial chromosome (PAC) contig spanning the MM candidate region. This clarified the order of genetic markers across the MM locus, provided five new polymorphic markers within it and narrowed the locus to approximately 2 Mb. Five skeletal muscle expressed sequence tags (ESTs) map in this region. We report that one of these is located in a novel, full-length 6.9-kb muscle cDNA, and we designate the corresponding protein 'dysferlin'. We describe nine mutations in the dysferlin gene in nine families; five are predicted to prevent dysferlin expression. Identical mutations in the dysferlin gene can produce more than one myopathy phenotype (MM, limb girdle dystrophy, distal myopathy with anterior tibial onset).
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Affiliation(s)
- J Liu
- Day Neuromuscular Research Laboratory, Charlestown, Massachusetts 02129, USA
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27
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28
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Affiliation(s)
- C L Ward
- Department of Morbid Anatomy, Institute of Pathology, Royal London Hospital, UK
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29
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Abstract
Advances in molecular genetics have disclosed many different explanations for allelic heterogeneity, how different clinical syndromes arise from mutations in the same gene. The converse, how similar clinical syndromes arise from mutations of different genes on different chromosomes is called locus heterogeneity. Both, however, give rise to some disease-defining mutations, as in childhood spinal muscular atrophy or Duchenne muscular dystrophy. Nevertheless, new problems have been created, including what might be called "diagnosis by the number," diverse syndromes from mutations in the same gene without current explanation, or siblings with different clinical syndromes. These discoveries have transformed the clinical neurology of heritable diseases. They also provide clinicians with new responsibilities and opportunities in defining clinical syndromes and influencing the evolution of our clinical language.
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Affiliation(s)
- L P Rowland
- Department of Neurology, Columbia University College of Physicians and Surgeons, New York, NY, USA
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30
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Abstract
Recently, it has been shown for mouse skeletal muscle that caveolin-3 is localized in the sarcolemma and cofractionates with the original dystrophin complex (DC). In order to find out whether caveolin-3 is a further component of the recently established and enlarged nitric oxide synthase (NOS) I-DC and whether members of this complex interact with and are potentially regulated by caveolin-3, mammalian and non-mammalian healthy and diseased (dystrophic) skeletal muscles were investigated using caveolin-3, NOS I, DC components and myosin immunohistochemistry as well as NOS I-associated diaphorase histochemistry. In healthy mammalian skeletal muscle, caveolin-3 was colocalized with the DC components in all extra- and intrafusal fibers. By contrast, NOS I was absent in type I extrafusal fibers of certain species. In patients with Duchenne muscular dystrophy and mdx mice the components of the NOS I-DC were not detected in all extra- and intrafusal fiber types, while caveolin-3 was found unchanged. In healthy non-mammalian skeletal muscle, i.e. of birds, reptiles and fishes, caveolin-3 immunoreactivity was lacking in the sarcolemma as was alpha-sarcoglycan; the other NOS I-DC components were either present or absent. In conclusion, although caveolin-3 is localized in the sarcolemma of mammalian myofibers, there are differences in the microarchitecture of the components of the DC complex and of caveolin-3 which does not appear to be linked with the NOS I-DC. Potential regulatory interactions between caveolin-3 and NOS I may nevertheless exist in those fibers where both molecules are colocalized. The absence of caveolin-3 and alpha-sarcoglycan immunoreactivities in non-mammalian myofibers may suggest that the functions of these proteins are subserved by other components of NOS I-DC complex.
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Affiliation(s)
- R Gossrau
- Institute of Anatomy, University Clinic Benjamin Franklin, Free University of Berlin, Germany
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31
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Stevenson S, Rothery S, Cullen MJ, Severs NJ. Spatial relationship of the C-terminal domains of dystrophin and beta-dystroglycan in cardiac muscle support a direct molecular interaction at the plasma membrane interface. Circ Res 1998; 82:82-93. [PMID: 9440707 DOI: 10.1161/01.res.82.1.82] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Dystrophin and beta-dystroglycan are components of a complex of at least nine proteins (the dystrophin-glycoprotein complex) that physically link the membrane cytoskeleton in skeletal and cardiac muscle, through the plasma membrane, to the extracellular matrix. Mutations in the dystrophin gene, which result in an absence or a quantitative or qualitative alteration of dystrophin, cause a subset of familial dilated cardiomyopathies as well as Duchenne and Becker muscular dystrophy. Biochemical studies on isolated skeletal muscle molecules indicate that dystrophin is bound to the glycoprotein complex via beta-dystroglycan, with the C-terminus of beta-dystroglycan binding to the cysteine-rich domain and first half of the C-terminal domain of dystrophin. Ultrastructural labeling has demonstrated a close spatial relationship between dystrophin and beta-dystroglycan in intact skeletal muscle, but no previous ultrastructural labeling studies have examined the dystrophin/beta-dystroglycan interaction in cardiac muscle. In the present study, we have applied complementary immunoconfocal microscopy and double immunogold fracture-label, a freeze-fracture cytochemical technique that allows high-resolution visualization of labeled membrane components in thin section and in platinum-carbon replicas, to investigate the spatial relationship between dystrophin and beta-dystroglycan in rat cardiac muscle. When immunogold probes of two different sizes for the two proteins were used, "doublets" representing side-by-side antibody labeling were demonstrated in en face views at the level of the plasma membrane. The results support the conclusions that dystrophin and beta-dystroglycan directly interact at the cytoplasmic face of the rat cardiac muscle plasma membrane.
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Affiliation(s)
- S Stevenson
- National Heart and Lung Institute, Imperial College School of Medicine, London, England
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