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Lamandé SR. Collagen VI Muscle Disorders: Mutation Types, Pathogenic Mechanisms and Approaches to Therapy. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2021; 1348:311-323. [PMID: 34807426 DOI: 10.1007/978-3-030-80614-9_14] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Mutations in the genes encoding the major collagen VI isoform, COL6A1, COL6A2 and COL6A3, are responsible for the muscle disorders Bethlem myopathy and Ullrich congenital muscular dystrophy. These disorders form a disease spectrum from mild to severe. Dominant and recessive mutations are found along the entire spectrum and the clinical phenotype is strongly influenced by the way mutations impede collagen VI protein assembly. Most mutations are in the triple helical domain, towards the N-terminus and they compromise microfibril assembly. Some mutations are found outside the helix in the C- and N-terminal globular domains, but because these regions are highly polymorphic it is difficult to discriminate mutations from rare benign changes without detailed structural and functional studies. Collagen VI deficiency leads to mitochondrial dysfunction, deficient autophagy and increased apoptosis. Therapies that target these consequences have been tested in mouse models and some have shown modest efficacy in small human trials. Antisense therapies for a common mutation that introduces a pseudoexon show promise in cell culture but haven't yet been tested in an animal model. Future therapeutic approaches await new research into how collagen VI deficiency signals downstream consequences.
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Affiliation(s)
- Shireen R Lamandé
- Murdoch Children's Research Institute and Department of Paediatrics, University of Melbourne, Royal Children's Hospital, Parkville, VIC, Australia.
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2
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Williams L, Layton T, Yang N, Feldmann M, Nanchahal J. Collagen VI as a driver and disease biomarker in human fibrosis. FEBS J 2021; 289:3603-3629. [PMID: 34109754 DOI: 10.1111/febs.16039] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2021] [Revised: 04/19/2021] [Accepted: 05/27/2021] [Indexed: 12/12/2022]
Abstract
Fibrosis of visceral organs such as the lungs, heart, kidneys and liver remains a major cause of morbidity and mortality and is also associated with many other disorders, including cancer and metabolic disease. In this review, we focus upon the microfibrillar collagen VI, which is present in the extracellular matrix (ECM) of most tissues. However, expression is elevated in numerous fibrotic conditions, such as idiopathic pulmonary disease (IPF), and chronic liver and kidney diseases. Collagen VI is composed of three subunits α1, α2 and α3, which can be replaced with alternate chains of α4, α5 or α6. The C-terminal globular domain (C5) of collagen VI α3 can be proteolytically cleaved to form a biologically active fragment termed endotrophin, which has been shown to actively drive fibrosis, inflammation and insulin resistance. Tissue biopsies have long been considered the gold standard for diagnosis and monitoring of progression of fibrotic disease. The identification of neoantigens from enzymatically processed collagen chains have revolutionised the biomarker field, allowing rapid diagnosis and evaluation of prognosis of numerous fibrotic conditions, as well as providing valuable clinical trial endpoint determinants. Collagen VI chain fragments such as endotrophin (PRO-C6), C6M and C6Mα3 are emerging as important biomarkers for fibrotic conditions.
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Affiliation(s)
- Lynn Williams
- Kennedy Institute of Rheumatology, Nuffield Department of Orthopaedics Rheumatology and Musculoskeletal Science, University of Oxford, UK
| | - Thomas Layton
- Kennedy Institute of Rheumatology, Nuffield Department of Orthopaedics Rheumatology and Musculoskeletal Science, University of Oxford, UK
| | - Nan Yang
- Kennedy Institute of Rheumatology, Nuffield Department of Orthopaedics Rheumatology and Musculoskeletal Science, University of Oxford, UK
| | - Marc Feldmann
- Kennedy Institute of Rheumatology, Nuffield Department of Orthopaedics Rheumatology and Musculoskeletal Science, University of Oxford, UK
| | - Jagdeep Nanchahal
- Kennedy Institute of Rheumatology, Nuffield Department of Orthopaedics Rheumatology and Musculoskeletal Science, University of Oxford, UK
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3
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Solomon-Degefa H, Gebauer JM, Jeffries CM, Freiburg CD, Meckelburg P, Bird LE, Baumann U, Svergun DI, Owens RJ, Werner JM, Behrmann E, Paulsson M, Wagener R. Structure of a collagen VI α3 chain VWA domain array: adaptability and functional implications of myopathy causing mutations. J Biol Chem 2020; 295:12755-12771. [PMID: 32719005 DOI: 10.1074/jbc.ra120.014865] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2020] [Revised: 07/16/2020] [Indexed: 12/23/2022] Open
Abstract
Collagen VI is a ubiquitous heterotrimeric protein of the extracellular matrix (ECM) that plays an essential role in the proper maintenance of skeletal muscle. Mutations in collagen VI lead to a spectrum of congenital myopathies, from the mild Bethlem myopathy to the severe Ullrich congenital muscular dystrophy. Collagen VI contains only a short triple helix and consists primarily of von Willebrand factor type A (VWA) domains, protein-protein interaction modules found in a range of ECM proteins. Disease-causing mutations occur commonly in the VWA domains, and the second VWA domain of the α3 chain, the N2 domain, harbors several such mutations. Here, we investigate structure-function relationships of the N2 mutations to shed light on their possible myopathy mechanisms. We determined the X-ray crystal structure of N2, combined with monitoring secretion efficiency in cell culture of selected N2 single-domain mutants, finding that mutations located within the central core of the domain severely affect secretion efficiency. In longer α3 chain constructs, spanning N6-N3, small-angle X-ray scattering demonstrates that the tandem VWA array has a modular architecture and samples multiple conformations in solution. Single-particle EM confirmed the presence of multiple conformations. Structural adaptability appears intrinsic to the VWA domain region of collagen VI α3 and has implications for binding interactions and modulating stiffness within the ECM.
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Affiliation(s)
| | - Jan M Gebauer
- Institute of Biochemistry, University of Cologne, Cologne, Germany
| | - Cy M Jeffries
- European Molecular Biology Laboratory, Hamburg Unit, Hamburg, Germany
| | - Carolin D Freiburg
- Center for Biochemistry, Medical Faculty, University of Cologne, Cologne, Germany
| | | | - Louise E Bird
- The Research Complex at Harwell, Rutherford Appleton Laboratory Harwell, Oxford, United Kingdom.,Structural Biology Division, Wellcome Human Genetics Centre, University of Oxford, Oxford, United Kingdom
| | - Ulrich Baumann
- Institute of Biochemistry, University of Cologne, Cologne, Germany
| | - Dmitri I Svergun
- European Molecular Biology Laboratory, Hamburg Unit, Hamburg, Germany
| | - Raymond J Owens
- The Research Complex at Harwell, Rutherford Appleton Laboratory Harwell, Oxford, United Kingdom.,Structural Biology Division, Wellcome Human Genetics Centre, University of Oxford, Oxford, United Kingdom
| | - Jörn M Werner
- School of Biological Sciences, University of Southampton, Southampton, United Kingdom
| | - Elmar Behrmann
- Institute of Biochemistry, University of Cologne, Cologne, Germany.,Max Planck Research Group Structural Dynamics of Proteins, Center of Advanced European Studies and Research (caesar), Bonn, Germany
| | - Mats Paulsson
- Center for Biochemistry, Medical Faculty, University of Cologne, Cologne, Germany.,Center for Molecular Medicine (CMMC), Cologne, Germany.,Cologne Center for Musculoskeletal Biomechanics (CCMB), Cologne, Germany
| | - Raimund Wagener
- Center for Biochemistry, Medical Faculty, University of Cologne, Cologne, Germany .,Center for Molecular Medicine (CMMC), Cologne, Germany.,Cologne Center for Musculoskeletal Biomechanics (CCMB), Cologne, Germany
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4
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Cescon M, Gattazzo F, Chen P, Bonaldo P. Collagen VI at a glance. J Cell Sci 2015; 128:3525-31. [DOI: 10.1242/jcs.169748] [Citation(s) in RCA: 175] [Impact Index Per Article: 19.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2015] [Accepted: 08/10/2015] [Indexed: 12/17/2022] Open
Abstract
Collagen VI represents a remarkable extracellular matrix molecule, and in the past few years, studies of this molecule have revealed its involvement in a wide range of tissues and pathological conditions. In addition to its complex multi-step pathway of biosynthesis and assembly that leads to the formation of a characteristic and distinctive network of beaded microfilaments in the extracellular matrix, collagen VI exerts several key roles in different tissues. These range from unique biomechanical roles to cytoprotective functions in different cells, including myofibers, chondrocytes, neurons, fibroblasts and cardiomyocytes. Indeed, collagen VI has been shown to exert a surprisingly broad range of cytoprotective effects, which include counteracting apoptosis and oxidative damage, favoring tumor growth and progression, regulating autophagy and cell differentiation, and even contributing to the maintenance of stemness. In this Cell Science at a Glance article and the accompanying poster, we present the current knowledge of collagen VI, and in particular, discuss its relevance in stemness and in preserving the mechanical properties of tissues, as well as its links with human disorders.
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Affiliation(s)
- Matilde Cescon
- Department of Molecular Medicine, University of Padova, Padova 35131, Italy
| | - Francesca Gattazzo
- Department of Molecular Medicine, University of Padova, Padova 35131, Italy
| | - Peiwen Chen
- Department of Molecular Medicine, University of Padova, Padova 35131, Italy
| | - Paolo Bonaldo
- Department of Molecular Medicine, University of Padova, Padova 35131, Italy
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5
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A structure of a collagen VI VWA domain displays N and C termini at opposite sides of the protein. Structure 2013; 22:199-208. [PMID: 24332716 PMCID: PMC3919171 DOI: 10.1016/j.str.2013.06.028] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2012] [Revised: 05/27/2013] [Accepted: 11/07/2013] [Indexed: 11/23/2022]
Abstract
Von Willebrand factor A (VWA) domains are versatile protein interaction domains with N and C termini in close proximity placing spatial constraints on overall protein structure. The 1.2 Å crystal structures of a collagen VI VWA domain and a disease-causing point mutant show C-terminal extensions that place the N and C termini at opposite ends. This allows a “beads-on-a-string” arrangement of multiple VWA domains as observed for ten N-terminal domains of the collagen VI α3 chain. The extension is linked to the core domain by a salt bridge and two hydrophobic patches. Comparison of the wild-type and a muscular dystrophy-associated mutant structure identifies a potential perturbation of a protein interaction interface and indeed, the secretion of mutant collagen VI tetramers is affected. Homology modeling is used to locate a number of disease-associated mutations and analyze their structural impact, which will allow mechanistic analysis of collagen-VI-associated muscular dystrophy phenotypes. The structure of a VWA domain (N5) of collagen VI at 1.2 Å is presented N and C termini of the domain are at opposite ends The structure with a myopathy-causing mutation shows altered interaction interface The impact of mutations in collagen VI VWA domains was analyzed
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Bernardi P, Bonaldo P. Mitochondrial dysfunction and defective autophagy in the pathogenesis of collagen VI muscular dystrophies. Cold Spring Harb Perspect Biol 2013; 5:a011387. [PMID: 23580791 DOI: 10.1101/cshperspect.a011387] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Ullrich Congenital Muscular Dystrophy (UCMD), Bethlem Myopathy (BM), and Congenital Myosclerosis are diseases caused by mutations in the genes encoding the extracellular matrix protein collagen VI. A dystrophic mouse model, where collagen VI synthesis was prevented by targeted inactivation of the Col6a1 gene, allowed the investigation of pathogenesis, which revealed the existence of a Ca(2+)-mediated dysfunction of mitochondria and sarcoplasmic reticulum, and of defective autophagy. Key events are dysregulation of the mitochondrial permeability transition pore, an inner membrane high-conductance channel that for prolonged open times causes mitochondrial dysfunction, and inadequate removal of defective mitochondria, which amplifies the damage. Consistently, the Col6a1(-/-) myopathic mice could be cured through inhibition of cyclophilin D, a matrix protein that sensitizes the pore to opening, and through stimulation of autophagy. Similar defects contribute to disease pathogenesis in patients irrespective of the genetic lesion causing the collagen VI defect. These studies indicate that permeability transition pore opening and defective autophagy represent key elements for skeletal muscle fiber death, and provide a rationale for the use of cyclosporin A and its nonimmunosuppressive derivatives in patients affected by collagen VI myopathies, a strategy that holds great promise for treatment.
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Affiliation(s)
- Paolo Bernardi
- Department of Biomedical Sciences, University of Padova, I-35121 Padova, Italy.
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ColVI myopathies: where do we stand, where do we go? Skelet Muscle 2011; 1:30. [PMID: 21943391 PMCID: PMC3189202 DOI: 10.1186/2044-5040-1-30] [Citation(s) in RCA: 73] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2011] [Accepted: 09/23/2011] [Indexed: 02/08/2023] Open
Abstract
Collagen VI myopathies, caused by mutations in the genes encoding collagen type VI (ColVI), represent a clinical continuum with Ullrich congenital muscular dystrophy (UCMD) and Bethlem myopathy (BM) at each end of the spectrum, and less well-defined intermediate phenotypes in between. ColVI myopathies also share common features with other disorders associated with prominent muscle contractures, making differential diagnosis difficult. This group of disorders, under-recognized for a long time, has aroused much interest over the past decade, with important advances made in understanding its molecular pathogenesis. Indeed, numerous mutations have now been reported in the COL6A1, COL6A2 and COL6A3 genes, a large proportion of which are de novo and exert dominant-negative effects. Genotype-phenotype correlations have also started to emerge, which reflect the various pathogenic mechanisms at play in these disorders: dominant de novo exon splicing that enables the synthesis and secretion of mutant tetramers and homozygous nonsense mutations that lead to premature termination of translation and complete loss of function are associated with early-onset, severe phenotypes. In this review, we present the current state of diagnosis and research in the field of ColVI myopathies. The past decade has provided significant advances, with the identification of altered cellular functions in animal models of ColVI myopathies and in patient samples. In particular, mitochondrial dysfunction and a defect in the autophagic clearance system of skeletal muscle have recently been reported, thereby opening potential therapeutic avenues.
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Tooley LD, Zamurs LK, Beecher N, Baker NL, Peat RA, Adams NE, Bateman JF, North KN, Baldock C, Lamandé SR. Collagen VI microfibril formation is abolished by an {alpha}2(VI) von Willebrand factor type A domain mutation in a patient with Ullrich congenital muscular dystrophy. J Biol Chem 2010; 285:33567-33576. [PMID: 20729548 PMCID: PMC2963345 DOI: 10.1074/jbc.m110.152520] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2010] [Revised: 07/22/2010] [Indexed: 11/06/2022] Open
Abstract
Collagen VI is an extracellular protein that most often contains the three genetically distinct polypeptide chains, α1(VI), α2(VI), and α3(VI), although three recently identified chains, α4(VI), α5(VI), and α6(VI), may replace α3(VI) in some situations. Each chain has a triple helix flanked by N- and C-terminal globular domains that share homology with the von Willebrand factor type A (VWA) domains. During biosynthesis, the three chains come together to form triple helical monomers, which then assemble into dimers and tetramers. Tetramers are secreted from the cell and align end-to-end to form microfibrils. The precise molecular mechanisms responsible for assembly are unclear. Mutations in the three collagen VI genes can disrupt collagen VI biosynthesis and matrix organization and are the cause of the inherited disorders Bethlem myopathy and Ullrich congenital muscular dystrophy. We have identified a Ullrich congenital muscular dystrophy patient with compound heterozygous mutations in α2(VI). The first mutation causes skipping of exon 24, and the mRNA is degraded by nonsense-mediated decay. The second mutation is a two-amino acid deletion in the C1 VWA domain. Recombinant C1 domains containing the deletion are insoluble and retained intracellularly, indicating that the mutation has detrimental effects on domain folding and structure. Despite this, mutant α2(VI) chains retain the ability to associate into monomers, dimers, and tetramers. However, we show that secreted mutant tetramers containing structurally abnormal C1 VWA domains are unable to associate further into microfibrils, directly demonstrating the critical importance of a correctly folded α2(VI) C1 domain in microfibril formation.
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Affiliation(s)
- Leona D Tooley
- From the Murdoch Childrens Research Institute, Parkville, Victoria 3052, Australia; Departments of Paediatrics, Parkville, Victoria 3052, Australia
| | - Laura K Zamurs
- From the Murdoch Childrens Research Institute, Parkville, Victoria 3052, Australia
| | - Nicola Beecher
- Wellcome Trust Centre for Cell Matrix Research, Faculty of Life Sciences, University of Manchester, Manchester M13 9PL, United Kingdom
| | - Naomi L Baker
- From the Murdoch Childrens Research Institute, Parkville, Victoria 3052, Australia
| | - Rachel A Peat
- Neurogenetics Research Unit, Children's Hospital at Westmead and Discipline of Paediatrics and Child Health, University of Sydney, Westmead, New South Wales 2145, Australia
| | - Naomi E Adams
- From the Murdoch Childrens Research Institute, Parkville, Victoria 3052, Australia
| | - John F Bateman
- From the Murdoch Childrens Research Institute, Parkville, Victoria 3052, Australia; Biochemistry and Molecular Biology, University of Melbourne, Royal Children's Hospital, Parkville, Victoria 3052, Australia
| | - Kathryn N North
- Neurogenetics Research Unit, Children's Hospital at Westmead and Discipline of Paediatrics and Child Health, University of Sydney, Westmead, New South Wales 2145, Australia
| | - Clair Baldock
- Wellcome Trust Centre for Cell Matrix Research, Faculty of Life Sciences, University of Manchester, Manchester M13 9PL, United Kingdom
| | - Shireen R Lamandé
- From the Murdoch Childrens Research Institute, Parkville, Victoria 3052, Australia; Departments of Paediatrics, Parkville, Victoria 3052, Australia.
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9
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Zhang RZ, Zou Y, Pan TC, Markova D, Fertala A, Hu Y, Squarzoni S, Reed UC, Marie SKN, Bönnemann CG, Chu ML. Recessive COL6A2 C-globular missense mutations in Ullrich congenital muscular dystrophy: role of the C2a splice variant. J Biol Chem 2010; 285:10005-10015. [PMID: 20106987 DOI: 10.1074/jbc.m109.093666] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Ullrich congenital muscular dystrophy (UCMD) is a disabling and life-threatening disorder resulting from either recessive or dominant mutations in genes encoding collagen VI. Although the majority of the recessive UCMD cases have frameshift or nonsense mutations in COL6A1, COL6A2, or COL6A3, recessive structural mutations in the COL6A2 C-globular region are emerging also. However, the underlying molecular mechanisms have remained elusive. Here we identified a homozygous COL6A2 E624K mutation (C1 subdomain) and a homozygous COL6A2 R876S mutation (C2 subdomain) in two UCMD patients. The consequences of the mutations were investigated using fibroblasts from patients and cells stably transfected with the mutant constructs. In contrast to expectations based on the clinical severity of these two patients, secretion and assembly of collagen VI were moderately affected by the E624K mutation but severely impaired by the R876S substitution. The E624K substitution altered the electrostatic potential of the region surrounding the metal ion-dependent adhesion site, resulting in a collagen VI network containing thick fibrils and spots with densely packed microfibrils. The R876S mutation prevented the chain from assembling into triple-helical collagen VI molecules. The minute amount of collagen VI secreted by the R876S fibroblasts was solely composed of a faster migrating chain corresponding to the C2a splice variant with an alternative C2 subdomain. In transfected cells, the C2a splice variant was able to assemble into short microfibrils. Together, the results suggest that the C2a splice variant may functionally compensate for the loss of the normal COL6A2 chain when mutations occur in the C2 subdomain.
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Affiliation(s)
- Rui-Zhu Zhang
- Departments of Dermatology and Cutaneous Biology, Philadelphia, Pennsylvania 19107
| | - Yaqun Zou
- Division of Neurology, The Children's Hospital of Philadelphia, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania 19104
| | - Te-Cheng Pan
- Departments of Dermatology and Cutaneous Biology, Philadelphia, Pennsylvania 19107
| | - Dessislava Markova
- Departments of Dermatology and Cutaneous Biology, Philadelphia, Pennsylvania 19107
| | - Andrzej Fertala
- Departments of Dermatology and Cutaneous Biology, Philadelphia, Pennsylvania 19107
| | - Ying Hu
- Division of Neurology, The Children's Hospital of Philadelphia, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania 19104
| | - Stefano Squarzoni
- Institute of Molecular Genetics-National Research Council, Unit of Bologna, 40136 Bologna, Italy
| | - Umbertina Conti Reed
- Departamento de Neurologia, Faculdade de Medicina da Universidade de Sao Paulo, O5403-000 Sao Paulo SP, Brazil
| | - Suely K N Marie
- Departamento de Neurologia, Faculdade de Medicina da Universidade de Sao Paulo, O5403-000 Sao Paulo SP, Brazil
| | - Carsten G Bönnemann
- Division of Neurology, The Children's Hospital of Philadelphia, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania 19104
| | - Mon-Li Chu
- Departments of Dermatology and Cutaneous Biology, Philadelphia, Pennsylvania 19107; Biochemistry and Molecular Biology, Thomas Jefferson University, Philadelphia, Pennsylvania 19107.
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10
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Bernardi P, Bonaldo P. Dysfunction of Mitochondria and Sarcoplasmic Reticulum in the Pathogenesis of Collagen VI Muscular Dystrophies. Ann N Y Acad Sci 2008; 1147:303-11. [DOI: 10.1196/annals.1427.009] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Huang Y, Choi MY, Au SWN, Au DMY, Lam VMS, Engel PC. Purification and detailed study of two clinically different human glucose 6-phosphate dehydrogenase variants, G6PD(Plymouth) and G6PD(Mahidol): Evidence for defective protein folding as the basis of disease. Mol Genet Metab 2008; 93:44-53. [PMID: 17959407 DOI: 10.1016/j.ymgme.2007.08.122] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/07/2007] [Revised: 08/17/2007] [Accepted: 08/18/2007] [Indexed: 11/23/2022]
Abstract
In an attempt to investigate the molecular mechanism underlying human glucose-6-phosphate dehydrogenase (G6PD) deficiency caused by two mutations, G6PD(Plymouth) (G163D) and G6PD(Mahidol) (G163S), the two variants were constructed by site-directed mutagenesis and expressed in G6PD-deficient E. coli DF 213 cells. A first indication of impaired folding came from problems in expressing these clinical mutants, which were only overcome by lowering the growth temperature or co-expressing with molecular chaperones (GroEL and GroES). Both strategies significantly increased soluble expression of recombinant G6PD(Plymouth) and G6PD(Mahidol), judged by both G6PD activity in extracts and the amount of immunoreactive protein. Using a modified 3-step protocol, the two mutant enzymes were successfully purified for the first time. Steady-state kinetic parameters (K(m) for NADP(+), K(m) for G6P and k(cat)) of the two mutants are very similar to the wild-type values, indicating that the catalytic efficiency of the two mutants remains unchanged. The two mutants are, however, markedly less stable than wild-type G6PD in both thermostability and urea-induced inactivation tests. In a typical experiment at 37 degrees C and pH 7.2 after 24h G6PD WT, G6PD(Mahidol) and G6PD(Plymouth) retained 58.3%, 27.0% and 3.9%, respectively, of their corresponding initial activity. The stability of all three enzymes is enhanced by addition of NADP(+). According to unfolding and refolding experiments, the two mutants are impaired in their folding properties. Thus structural instability appears to be the molecular basis of the clinical phenotype in G6PD(Plymouth) and G6PD(Mahidol) and in particular of the differing clinical severity of the two mutations. The 3-D structure solved for G6PD(Canton) allows an interpretation of these effects in terms of steric hindrance.
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Affiliation(s)
- Yuxiang Huang
- Department of Biochemistry, The University of Hong Kong, Hong Kong SAR, China
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12
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Baker NL, Mörgelin M, Pace RA, Peat RA, Adams NE, Gardner RJM, Rowland LP, Miller G, De Jonghe P, Ceulemans B, Hannibal MC, Edwards M, Thompson EM, Jacobson R, Quinlivan RCM, Aftimos S, Kornberg AJ, North KN, Bateman JF, Lamandé SR. Molecular consequences of dominant Bethlem myopathy collagen VI mutations. Ann Neurol 2007; 62:390-405. [PMID: 17886299 DOI: 10.1002/ana.21213] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
OBJECTIVE Dominant mutations in the three collagen VI genes cause Bethlem myopathy, a disorder characterized by proximal muscle weakness and commonly contractures of the fingers, wrists, and ankles. Although more than 20 different dominant mutations have been identified in Bethlem myopathy patients, the biosynthetic consequences of only a subset of these have been studied, and in many cases, the pathogenic mechanisms remain unknown. METHODS We have screened fourteen Bethlem myopathy patients for collagen VI mutations and performed detailed analyses of collagen VI biosynthesis and intracellular and extracellular assembly. RESULTS Collagen VI abnormalities were identified in eight patients. One patient produced around half the normal amount of alpha1(VI) messenger RNA and reduced amounts of collagen VI protein. Two patients had a previously reported mutation causing skipping of COL6A1 exon 14, and three patients had novel mutations leading to in-frame deletions toward the N-terminal end of the triple-helical domain. These mutations have different and complex effects on collagen VI intracellular and extracellular assembly. Two patients had single amino acid substitutions in the A-domains of COL6A2 and COL6A3. Collagen VI intracellular and extracellular assembly was normal in one of these patients. INTERPRETATION The key to dissecting the pathogenic mechanisms of collagen VI mutations lies in detailed analysis of collagen VI biosynthesis and assembly. The majority of mutations result in secretion and deposition of structurally abnormal collagen VI. However, one A-domain mutation had no detectable effect on assembly, suggesting that it acts by compromising collagen VI interactions in the extracellular matrix of muscle.
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Affiliation(s)
- Naomi L Baker
- Murdoch Childrens Research Institute and Department of Paediatrics, University of Melbourne, Royal Children's Hospital, Parkville, Victoria, Australia
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Abstract
Mutations in the genes encoding collagen VI (COL6A1, COL6A2, and COL6A3) cause Bethlem myopathy (BM) and Ullrich congenital muscular dystrophy (UCMD), two conditions which were previously believed to be completely separate entities. BM is a relatively mild dominantly inherited disorder characterised by proximal weakness and distal joint contractures. UCMD was originally described as an autosomal recessive condition causing severe muscle weakness with proximal joint contractures and distal hyperlaxity. Here we review the clinical phenotypes of BM and UCMD and their diagnosis and management, and provide an overview of the current knowledge of the pathogenesis of collagen VI related disorders.
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Affiliation(s)
- A K Lampe
- Institute of Human Genetics, University of Newcastle upon Tyne, International Centre for Life, Central Parkway, Newcastle upon Tyne, NE1 3BZ.
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Cotterill SL, Jackson GC, Leighton MP, Wagener R, Mäkitie O, Cole WG, Briggs MD. Multiple epiphyseal dysplasia mutations in MATN3 cause misfolding of the A-domain and prevent secretion of mutant matrilin-3. Hum Mutat 2006; 26:557-65. [PMID: 16287128 PMCID: PMC2726956 DOI: 10.1002/humu.20263] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Multiple epiphyseal dysplasia (MED) is a relatively common skeletal dysplasia that can present in childhood with a variable phenotype of short stature and pain and stiffness in the large joints, and often progresses to early-onset osteoarthritis in adulthood. Mutations in the matrilin-3 gene (MATN3) have recently been shown to underlie some forms of autosomal dominant MED. To date all MED mutations in matrilin-3 cluster in the single A-domain, suggesting that they may disrupt the structure and/or function of this important domain. To determine the effects of MATN3 mutations on the structure and function of matrilin-3 we expressed both normal and mutant matrilin-3 in mammalian cells. Wild-type (wt) matrilin-3 was efficiently secreted into conditioned medium, whereas mutant matrilin-3 was retained and accumulated within the cell. Furthermore, when the mutant A-domains were examined individually, they existed primarily in an unfolded conformation. Co-immunoprecipitation experiments demonstrated that the mutant A-domains were specifically associated with ERp72, a chaperone protein known to be involved in mediating disulfide bond formation. Light microscopy of cartilage from an MED patient with a MATN3 mutation showed the presence of intracellular material within the chondrocytes, whilst the overall matrix appeared normal. On electron micrographs, the inclusions noted at the light microscopy level appeared to be dilated cisternae of rough endoplasmic reticulum and immunohistochemical analysis confirmed that the retained protein was matrilin-3. In summary, the data presented in this paper suggest that MED caused by MATN3 mutations is the result of an intracellular retention of the mutant protein.
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Affiliation(s)
- Sally L Cotterill
- Wellcome Trust Centre for Cell-Matrix Research, Faculty of Life Sciences, University of ManchesterManchester, United Kingdom
| | - Gail C Jackson
- Wellcome Trust Centre for Cell-Matrix Research, Faculty of Life Sciences, University of ManchesterManchester, United Kingdom
| | - Matthew P Leighton
- Wellcome Trust Centre for Cell-Matrix Research, Faculty of Life Sciences, University of ManchesterManchester, United Kingdom
| | - Raimund Wagener
- Center for Biochemistry, University of CologneCologne, Germany
| | - Outi Mäkitie
- Hospital for Children and Adolescents, University of HelsinkiHelsinki, Finland
| | | | - Michael D Briggs
- Wellcome Trust Centre for Cell-Matrix Research, Faculty of Life Sciences, University of ManchesterManchester, United Kingdom
- *Correspondence to: Michael D. Briggs, Wellcome Trust Centre for Cell-Matrix Research, Faculty of Life Sciences, University of Manchester, Manchester M13 9PT, United Kingdom. E-mail:
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15
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Lampe AK, Dunn DM, von Niederhausern AC, Hamil C, Aoyagi A, Laval SH, Marie SK, Chu ML, Swoboda K, Muntoni F, Bonnemann CG, Flanigan KM, Bushby KMD, Weiss RB. Automated genomic sequence analysis of the three collagen VI genes: applications to Ullrich congenital muscular dystrophy and Bethlem myopathy. J Med Genet 2006; 42:108-20. [PMID: 15689448 PMCID: PMC1736000 DOI: 10.1136/jmg.2004.023754] [Citation(s) in RCA: 96] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
INTRODUCTION Mutations in the genes encoding collagen VI (COL6A1, COL6A2, and COL6A3) cause Bethlem myopathy (BM) and Ullrich congenital muscular dystrophy (UCMD). BM is a relatively mild dominantly inherited disorder with proximal weakness and distal joint contractures. UCMD is an autosomal recessive condition causing severe muscle weakness with proximal joint contractures and distal hyperlaxity. METHODS We developed a method for rapid direct sequence analysis of all 107 coding exons of the COL6 genes using single condition amplification/internal primer (SCAIP) sequencing. We have sequenced all three COL6 genes from genomic DNA in 79 patients with UCMD or BM. RESULTS We found putative mutations in one of the COL6 genes in 62% of patients. This more than doubles the number of identified COL6 mutations. Most of these changes are consistent with straightforward autosomal dominant or recessive inheritance. However, some patients showed changes in more than one of the COL6 genes, and our results suggest that some UCMD patients may have dominantly acting mutations rather than recessive disease. DISCUSSION Our findings may explain some or all of the cases of UCMD that are unlinked to the COL6 loci under a recessive model. The large number of single nucleotide polymorphisms which we generated in the course of this work may be of importance in determining the major phenotypic variability seen in this group of disorders.
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Affiliation(s)
- A K Lampe
- Institute of Human Genetics, University of Newcastle upon Tyne, Newcastle upon Tyne, UK
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16
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Scaturro M, Posteraro P, Mastrogiacomo A, Zaccaria ML, De Luca N, Mazzanti C, Zambruno G, Castiglia D. A missense mutation (G1506E) in the adhesion G domain of laminin-5 causes mild junctional epidermolysis bullosa. Biochem Biophys Res Commun 2003; 309:96-103. [PMID: 12943669 DOI: 10.1016/s0006-291x(03)01533-x] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Laminin-5 is the major adhesion ligand for epithelial cells. Mutations in the genes encoding laminin-5 cause junctional epidermolysis bullosa (JEB), a recessive inherited disease characterized by extensive epithelial-mesenchymal disadhesion. We describe a JEB patient compound heterozygote for two novel mutations in the gene (LAMA3) encoding the laminin alpha3 chain. The maternal mutation (1644delG) generates mRNA transcripts that undergo nonsense-mediated decay. The paternal mutation results in the Gly1506-->Glu substitution (G1506E) within the C-terminal globular region of the alpha3 chain (G domain). Mutation G1506E affects the proper folding of the fourth module of the G domain and results in the retention of most of the mutated polypeptide within the endoplasmic reticulum (ER). However, scant amounts of the mutated laminin-5 are secreted, undergo physiologic extracellular maturation, and correctly localize within the cutaneous basement membrane zone in patient's skin. Our findings represent the first demonstration of an ER-retained mutant laminin-5 leading to a mild JEB phenotype.
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MESH Headings
- Adult
- Alleles
- Amino Acid Sequence
- Base Sequence
- Blotting, Northern
- Cell Adhesion
- Cell Adhesion Molecules/chemistry
- Cell Adhesion Molecules/genetics
- Cells, Cultured
- Codon, Nonsense
- DNA Mutational Analysis
- Endoplasmic Reticulum/metabolism
- Epidermolysis Bullosa, Junctional/genetics
- Fathers
- Female
- Genes, Recessive
- Glutamic Acid/chemistry
- Glycine/chemistry
- Heterozygote
- Humans
- Keratinocytes/metabolism
- Laminin/chemistry
- Laminin/genetics
- Male
- Microscopy, Fluorescence
- Microscopy, Immunoelectron
- Models, Molecular
- Molecular Sequence Data
- Mothers
- Mutation
- Mutation, Missense
- Peptides/chemistry
- Phenotype
- Precipitin Tests
- Protein Folding
- Protein Structure, Tertiary
- RNA, Messenger/metabolism
- Sequence Homology, Amino Acid
- Kalinin
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17
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Leitinger B. Molecular analysis of collagen binding by the human discoidin domain receptors, DDR1 and DDR2. Identification of collagen binding sites in DDR2. J Biol Chem 2003; 278:16761-9. [PMID: 12611880 DOI: 10.1074/jbc.m301370200] [Citation(s) in RCA: 155] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The widely expressed mammalian discoidin domain receptors (DDRs), DDR1 and DDR2, are unique among receptor tyrosine kinases in that they are activated by the extracellular matrix protein collagen. Various collagen types bind to and activate the DDRs, but the molecular details of collagen recognition have not been well defined. In this study, recombinant extracellular domains of DDR1 and DDR2 were produced to explore DDR-collagen binding in detail. In solid phase assays, both DDRs bound collagen I with high affinity. DDR1 recognized collagen I only as a dimeric and not as a monomeric construct, indicating a requirement for receptor dimerization in the DDR1-collagen interaction. The DDRs contain a discoidin homology domain in their extracellular domains, and the isolated discoidin domain of DDR2 bound collagen I with high affinity. Furthermore, the discoidin domain of DDR2, but not of DDR1, was sufficient for transmembrane receptor signaling. To map the collagen binding site within the discoidin domain of DDR2, mutant constructs were created, in which potential surface-exposed loops in DDR2 were exchanged for the corresponding loops of functionally unrelated discoidin domains. Three spatially adjacent surface loops within the DDR2 discoidin domain were found to be critically involved in collagen binding of the isolated DDR2 extracellular domain. In addition, the same loops were required for collagen-dependent receptor activation. It is concluded that the loop region opposite to the polypeptide chain termini of the DDR2 discoidin domain constitutes the collagen recognition site.
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Affiliation(s)
- Birgit Leitinger
- Sackler Institute for Muscular Skeletal Research, Department of Medicine, University College London, 5 University St., London WC1E 6JJ, United Kingdom.
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18
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Wiberg C, Heinegård D, Wenglén C, Timpl R, Mörgelin M. Biglycan organizes collagen VI into hexagonal-like networks resembling tissue structures. J Biol Chem 2002; 277:49120-6. [PMID: 12354766 DOI: 10.1074/jbc.m206891200] [Citation(s) in RCA: 142] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The ability of the leucine-rich repeat (LRR) proteins biglycan, decorin, and chondroadherin to interact with collagen VI and influence its assembly to supramolecular structures was studied by electron microscopy and surface plasmon resonance measurements in the BIAcore 2000 system. Biglycan showed a unique ability to organize collagen VI into extensive hexagonal-like networks over a time period of only a few minutes. Only the intact molecule, substituted with two dermatan sulfate chains, had this capacity. Intact decorin, with one dermatan sulfate chain only, was considerably less efficient, and aggregates of organized collagen VI were found only after several hours. Chondroadherin without glycosaminoglycan substitutions did not induce any ordered collagen VI organization. However, all three related LRR proteins were shown to interact with collagen VI using electron microscopy and surface plasmon resonance. Biglycan and decorin were exclusively found close to the N-terminal parts of the collagen VI tetramers, whereas chondroadherin was shown to bind close to both the N- and C-terminal parts of collagen VI. In the formed hexagonal networks, biglycan was localized to the intra-network junctions of the collagen VI filaments. This was demonstrated by electron microscopy after negative staining of gold-labeled biglycan in aggregation experiments with collagen VI.
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Affiliation(s)
- Charlotte Wiberg
- Department of Cell and Molecular Biology, University of Lund, BMC, S-221 84 Lund, Sweden
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19
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Adams CR, Figueroa KP, Zu L, Anderson TL, Graves MC, Garcia CA, Pulst SM. Bethlem myopathy in a black creole pedigree. J Clin Neuromuscul Dis 2002; 4:7-10. [PMID: 19078680 DOI: 10.1097/00131402-200209000-00002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
OBJECTIVES To analyze the clinical and molecular features of a distinctive muscular dystrophy in a family of black Creole descent. METHODS We clinically characterized a four-generation pedigree and performed linkage analysis for all relevant autosomal-dominant muscular dystrophies. RESULTS Affected family members had minor neurologic dissimilarities from previously reported Bethlem myopathy pedigrees and a high incidence of keloid formation. Multipoint linkage analysis traced the family's disease to the region of the collagen genes COL6A1-COL6A2. CONCLUSIONS We report that Bethlem myopathy was linked to the collagen VIA1-2 region on chromosome 21q22.3 in a black Creole family. This is the first report of molecular-proven Bethlem myopathy in a family of either Creole or African-American descent. Although the correlation of Bethlem myopathy and keloids was not statistically significant, the possible connection between these two abnormalities raises the possibility of a common pathophysiological link involving collage VIA.
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Affiliation(s)
- Cameron R Adams
- From the *Division of Neurology, Cedars-Sinai Medical Center; Los Angeles, California; the daggerDepartment of Neurology, UCLA; Los Angeles, California; and the double daggerDepartment of Neurology, Tulane University, New Orleans, Louisiana
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20
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Demir E, Sabatelli P, Allamand V, Ferreiro A, Moghadaszadeh B, Makrelouf M, Topaloglu H, Echenne B, Merlini L, Guicheney P. Mutations in COL6A3 cause severe and mild phenotypes of Ullrich congenital muscular dystrophy. Am J Hum Genet 2002; 70:1446-58. [PMID: 11992252 PMCID: PMC419991 DOI: 10.1086/340608] [Citation(s) in RCA: 106] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2001] [Accepted: 03/06/2002] [Indexed: 11/04/2022] Open
Abstract
Ullrich congenital muscular dystrophy (UCMD) is an autosomal recessive disorder characterized by generalized muscular weakness, contractures of multiple joints, and distal hyperextensibility. Homozygous and compound heterozygous mutations of COL6A2 on chromosome 21q22 have recently been shown to cause UCMD. We performed a genomewide screening with microsatellite markers in a consanguineous family with three sibs affected with UCMD. Linkage of the disease to chromosome 2q37 was found in this family and in two others. We analyzed COL6A3, which encodes the alpha3 chain of collagen VI, and identified one homozygous mutation per family. In family I, the three sibs carried an A-->G transition in the splice-donor site of intron 29 (6930+5A-->G), leading to the skipping of exon 29, a partial reduction of collagen VI in muscle biopsy, and an intermediate phenotype. In family II, the patient had an unusual mild phenotype, despite a nonsense mutation, R465X, in exon 5. Analysis of the patient's COL6A3 transcripts showed the presence of various mRNA species-one of which lacked several exons, including the exon containing the nonsense mutation. The deleted splice variant encodes collagen molecules that have a shorter N-terminal domain but that may assemble with other chains and retain a functional role. This could explain the mild phenotype of the patient who was still ambulant at age 18 years and who showed an unusual combination of hyperlaxity and finger contractures. In family III, the patient had a nonsense mutation, R2342X, causing absence of collagen VI in muscle and fibroblasts, and a severe phenotype, as has been described in patients with UCMD. Mutations in COL6A3 are described in UCMD for the first time and illustrate the wide spectrum of phenotypes which can be caused by collagen VI deficiency.
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Affiliation(s)
- Ercan Demir
- INSERM U 523, Institut de Myologie, Groupe Hospitalier Pitié-Salpêtrière, Paris; Istituto di Citomorfologia Normale e Patologica, Consiglio Nazionale delle Ricerche c/o Istituto Ortopedico Rizzoli, and Neuromuscular Unit, Rizzoli Orthopedic Institut, Bologna; Department of Paediatric Neurology, Hacettepe Children's Hospital, Ankara; and Service de Neuropédiatrie, Hôpital Saint Eloi, Montpellier, France
| | - Patrizia Sabatelli
- INSERM U 523, Institut de Myologie, Groupe Hospitalier Pitié-Salpêtrière, Paris; Istituto di Citomorfologia Normale e Patologica, Consiglio Nazionale delle Ricerche c/o Istituto Ortopedico Rizzoli, and Neuromuscular Unit, Rizzoli Orthopedic Institut, Bologna; Department of Paediatric Neurology, Hacettepe Children's Hospital, Ankara; and Service de Neuropédiatrie, Hôpital Saint Eloi, Montpellier, France
| | - Valérie Allamand
- INSERM U 523, Institut de Myologie, Groupe Hospitalier Pitié-Salpêtrière, Paris; Istituto di Citomorfologia Normale e Patologica, Consiglio Nazionale delle Ricerche c/o Istituto Ortopedico Rizzoli, and Neuromuscular Unit, Rizzoli Orthopedic Institut, Bologna; Department of Paediatric Neurology, Hacettepe Children's Hospital, Ankara; and Service de Neuropédiatrie, Hôpital Saint Eloi, Montpellier, France
| | - Ana Ferreiro
- INSERM U 523, Institut de Myologie, Groupe Hospitalier Pitié-Salpêtrière, Paris; Istituto di Citomorfologia Normale e Patologica, Consiglio Nazionale delle Ricerche c/o Istituto Ortopedico Rizzoli, and Neuromuscular Unit, Rizzoli Orthopedic Institut, Bologna; Department of Paediatric Neurology, Hacettepe Children's Hospital, Ankara; and Service de Neuropédiatrie, Hôpital Saint Eloi, Montpellier, France
| | - Behzad Moghadaszadeh
- INSERM U 523, Institut de Myologie, Groupe Hospitalier Pitié-Salpêtrière, Paris; Istituto di Citomorfologia Normale e Patologica, Consiglio Nazionale delle Ricerche c/o Istituto Ortopedico Rizzoli, and Neuromuscular Unit, Rizzoli Orthopedic Institut, Bologna; Department of Paediatric Neurology, Hacettepe Children's Hospital, Ankara; and Service de Neuropédiatrie, Hôpital Saint Eloi, Montpellier, France
| | - Mohamed Makrelouf
- INSERM U 523, Institut de Myologie, Groupe Hospitalier Pitié-Salpêtrière, Paris; Istituto di Citomorfologia Normale e Patologica, Consiglio Nazionale delle Ricerche c/o Istituto Ortopedico Rizzoli, and Neuromuscular Unit, Rizzoli Orthopedic Institut, Bologna; Department of Paediatric Neurology, Hacettepe Children's Hospital, Ankara; and Service de Neuropédiatrie, Hôpital Saint Eloi, Montpellier, France
| | - Haluk Topaloglu
- INSERM U 523, Institut de Myologie, Groupe Hospitalier Pitié-Salpêtrière, Paris; Istituto di Citomorfologia Normale e Patologica, Consiglio Nazionale delle Ricerche c/o Istituto Ortopedico Rizzoli, and Neuromuscular Unit, Rizzoli Orthopedic Institut, Bologna; Department of Paediatric Neurology, Hacettepe Children's Hospital, Ankara; and Service de Neuropédiatrie, Hôpital Saint Eloi, Montpellier, France
| | - Bernard Echenne
- INSERM U 523, Institut de Myologie, Groupe Hospitalier Pitié-Salpêtrière, Paris; Istituto di Citomorfologia Normale e Patologica, Consiglio Nazionale delle Ricerche c/o Istituto Ortopedico Rizzoli, and Neuromuscular Unit, Rizzoli Orthopedic Institut, Bologna; Department of Paediatric Neurology, Hacettepe Children's Hospital, Ankara; and Service de Neuropédiatrie, Hôpital Saint Eloi, Montpellier, France
| | - Luciano Merlini
- INSERM U 523, Institut de Myologie, Groupe Hospitalier Pitié-Salpêtrière, Paris; Istituto di Citomorfologia Normale e Patologica, Consiglio Nazionale delle Ricerche c/o Istituto Ortopedico Rizzoli, and Neuromuscular Unit, Rizzoli Orthopedic Institut, Bologna; Department of Paediatric Neurology, Hacettepe Children's Hospital, Ankara; and Service de Neuropédiatrie, Hôpital Saint Eloi, Montpellier, France
| | - Pascale Guicheney
- INSERM U 523, Institut de Myologie, Groupe Hospitalier Pitié-Salpêtrière, Paris; Istituto di Citomorfologia Normale e Patologica, Consiglio Nazionale delle Ricerche c/o Istituto Ortopedico Rizzoli, and Neuromuscular Unit, Rizzoli Orthopedic Institut, Bologna; Department of Paediatric Neurology, Hacettepe Children's Hospital, Ankara; and Service de Neuropédiatrie, Hôpital Saint Eloi, Montpellier, France
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21
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Bönnemann CG, Finkel RS. Sarcolemmal proteins and the spectrum of limb-girdle muscular dystrophies. Semin Pediatr Neurol 2002; 9:81-99. [PMID: 12139001 DOI: 10.1053/spen.2002.33795] [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: 01/07/2023]
Abstract
Proteins of the sarcolemma are of crucial importance for the pathogenesis of muscular dystrophies. This update focuses on the dystrophin-associated proteins including the dystroglycan and sarcoglycan complexes, caveolin-3, dysferlin, and the extracellular matrix component collagen type VI. The molecular findings are correlated with some of the clinical phenotypes that are part of the limb-girdle muscular dystrophy spectrum, including fukutin-related proteinopathy (LGMD 21), the sarcoglycanopathies (LGMD 2C-F), caveolinopathy (LGMD 1C), dysferlinopathy (LGMD 2B), and finally Bethlem myopathy. Although recent progress has been tremendous, much remains to be learned about the pathophysiological consequences caused by a deficiency of any one of these components.
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Affiliation(s)
- Carsten G Bönnemann
- Division of Neurology, The Children's Hospital of Philadelphia, PA 19104, USA
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22
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Lamandé SR, Mörgelin M, Selan C, Jöbsis GJ, Baas F, Bateman JF. Kinked collagen VI tetramers and reduced microfibril formation as a result of Bethlem myopathy and introduced triple helical glycine mutations. J Biol Chem 2002; 277:1949-56. [PMID: 11707460 DOI: 10.1074/jbc.m109932200] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Mutations in the genes that code for collagen VI subunits, COL6A1, COL6A2, and COL6A3, are the cause of the dominantly inherited disorder, Bethlem myopathy. Glycine mutations that interrupt the Gly-X-Y repetitive amino acid sequence that forms the characteristic collagen triple helix have been defined in four families; however, the effects of these mutations on collagen VI biosynthesis, assembly, and structure have not been determined. In this study, we examined the consequences of Bethlem myopathy triple helical glycine mutations in the alpha1(VI) and alpha2(VI) chains, as well as engineered alpha3(VI) triple helical glycine mutations. Although the Bethlem myopathy and introduced mutations that are toward the N terminus of the triple helix did not measurably affect collagen VI intracellular monomer, dimer, or tetramer assembly, or secretion, the introduced mutation toward the C terminus of the helix severely impaired association of the mutant alpha3(VI) chain with alpha1(VI) and alpha2(VI). Association of the three chains was not completely prevented, however; and some non-disulfide bonded tetramers were secreted. Examination of the secreted Bethlem myopathy and engineered mutant collagen VI by negative staining electron microscopy revealed the striking finding that in all the cell lines a significant proportion of the tetramers contained a kink in the supercoiled triple helical region. Collagen VI tetramers from all of the mutant cell lines also showed a reduced ability to form microfibrils. These results provide the first evidence of the biosynthetic consequences of collagen VI triple helical glycine mutations and indicate that Bethlem myopathy results not only from the synthesis of reduced amounts of structurally normal protein but also from the presence of mutant collagen VI in the extracellular matrix.
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Affiliation(s)
- Shireen R Lamandé
- Cell and Matrix Biology Research Unit, Department of Paediatrics, University of Melbourne, the Murdoch Childrens Research Institute, Royal Children's Hospital, Parkville, Victoria 3052, Australia.
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Gordon ES, Hoffman EP. The ABC's of limb-girdle muscular dystrophy: alpha-sarcoglycanopathy, Bethlem myopathy, calpainopathy and more. Curr Opin Neurol 2001; 14:567-73. [PMID: 11562567 DOI: 10.1097/00019052-200110000-00004] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Limb-girdle muscular dystrophy is a class of disorders encompassing many forms of this disease. Variation exists between the inheritance patterns, genes responsible, course of disease and symptoms, with the cohesive factor among these disorders being the predominance of proximal muscle weakness. Here we review each form of limb-girdle muscular dystrophy with attention to molecular genetics, clinical features, inheritance, and diagnostic issues pertaining to each primary genetic cause.
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Affiliation(s)
- E S Gordon
- Research Center for Genetic Medicine, Children's National Medical Center, Washington, DC 20010, USA
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24
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Chapman KL, Mortier GR, Chapman K, Loughlin J, Grant ME, Briggs MD. Mutations in the region encoding the von Willebrand factor A domain of matrilin-3 are associated with multiple epiphyseal dysplasia. Nat Genet 2001; 28:393-6. [PMID: 11479597 DOI: 10.1038/ng573] [Citation(s) in RCA: 154] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Multiple epiphyseal dysplasia (MED) is a relatively mild and clinically variable osteochondrodysplasia, primarily characterized by delayed and irregular ossification of the epiphyses and early-onset osteoarthritis. Mutations in the genes encoding cartilage oligomeric matrix protein (COMP) and type IX collagen (COL9A2 and COL9A3) have previously been shown to cause different forms of MED (refs. 4-13). These dominant forms of MED (EDM1-3) are caused by mutations in the genes encoding structural proteins of the cartilage extracellular matrix (ECM); these proteins interact with high affinity in vitro. A recessive form of MED (EDM4) has also been reported; it is caused by a mutation in the diastrophic dysplasia sulfate transporter gene (SLC26A). A genomewide screen of family with autosomal-dominant MED not linked to the EDM1-3 genes provides significant genetic evidence for a MED locus on the short arm of chromosome 2 (2p24-p23), and a search for candidate genes identified MATN3 (ref. 18), encoding matrilin-3, within the critical region. Matrilin-3 is an oligomeric protein that is present in the cartilage ECM. We have identified two different missense mutations in the exon encoding the von Willebrand factor A (vWFA) domain of matrilin-3 in two unrelated families with MED (EDM5). These are the first mutations to be identified in any of the genes encoding the matrilin family of proteins and confirm a role for matrilin-3 in the development and homeostasis of cartilage and bone.
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Affiliation(s)
- K L Chapman
- Wellcome Trust Centre for Cell-Matrix Research, School of Biological Sciences, University of Manchester, Manchester, UK
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