1
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Wu H, Wang S, Li G, Yao Y, Wang N, Sun X, Fang L, Jiang X, Zhao J, Wang Y, Xu C. Characterization of a novel COL10A1 variant associated with Schmid-type metaphyseal chondrodysplasia and a literature review. Mol Genet Genomic Med 2021; 9:e1668. [PMID: 33764685 PMCID: PMC8172203 DOI: 10.1002/mgg3.1668] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2020] [Revised: 07/22/2020] [Accepted: 02/19/2021] [Indexed: 12/05/2022] Open
Abstract
Background Schmid‐type metaphyseal chondrodysplasia (SMCD) is a rare autosomal dominant skeletal dysplasia caused by heterozygous mutations in COL10A1, the gene which encodes collagen type X alpha 1 chain. However, its genotype–phenotype relationship has not been fully determined. Subjects and Methods The proband is a 2‐year‐old boy, born of non‐consanguineous Chinese parents. We conducted a systematic analysis of the clinical and radiological characteristics and a follow‐up study of the proband. Whole‐exome sequencing was applied for the genetic analysis, together with bioinformatic analysis of predicted consequences of the identified variant. A homotrimer model was built to visualize the affected region and predict possible outcomes of this variant. Furthermore, a literature review and genotype–phenotype analysis were performed by online searching all cases with SMCD. Results A novel heterozygous variant (NM_000493.4: c.1863_1866delAATG, NP_000484.2: p.(Met622 Thrfs*54)) was identified in COL10A1 gene in the affected child. And it was predicted to be pathogenic by in silico analysis. Protein modeling revealed that the variant was located in the NC1 domain, which was predicted to produce truncated collagen and impair the trimerization of collagen type X alpha 1 chain and combination with molecules in the matrix. Moreover, genotype–phenotype correlation analysis demonstrated that patients with truncating variants or variants in NC1 domain often presented earlier onset and severer symptoms compared with those with non‐truncating or variants in non‐NC1 domains. Conclusion The NC1 domain of COL10A1 was proved to be the hotspot region underlying SMCD, patients with variants in NC1 domain were more likely to present severer manifestations at an earlier age.
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Affiliation(s)
- Huixiao Wu
- Department of Endocrinology and Metabolism, Shandong Provincial Hospital, Cheeloo College of Medicine, Shandong University, Jinan, China.,Department of Endocrinology and Metabolism, Shandong Provincial Hospital Affiliated to Shandong First Medical University, Jinan, China.,Institute of Endocrinology, Shandong Academy of Clinical Medicine, Jinan, China.,Shandong Clinical Medical Center of Endocrinology and Metabolism, Jinan, China
| | - Shuping Wang
- Department of Endocrinology and Metabolism, Shandong Provincial Hospital, Cheeloo College of Medicine, Shandong University, Jinan, China.,Department of Endocrinology and Metabolism, Dongying people's Hospital, Dongying, China
| | - Guimei Li
- Department of Pediatric, Shandong Provincial Hospital Affiliated to Shandong First Medical University, Jinan, China
| | - Yangyang Yao
- Department of Pediatric Orthopedics, Shandong Provincial Hospital Affiliated to Shandong First Medical University, Jinan, China
| | - Ning Wang
- Institute of Endocrinology, Shandong Academy of Clinical Medicine, Jinan, China.,Shandong Clinical Medical Center of Endocrinology and Metabolism, Jinan, China
| | - Xiaoqing Sun
- Institute of Endocrinology, Shandong Academy of Clinical Medicine, Jinan, China.,Shandong Clinical Medical Center of Endocrinology and Metabolism, Jinan, China
| | - Li Fang
- Department of Endocrinology and Metabolism, Shandong Provincial Hospital, Cheeloo College of Medicine, Shandong University, Jinan, China.,Department of Endocrinology and Metabolism, Shandong Provincial Hospital Affiliated to Shandong First Medical University, Jinan, China.,Institute of Endocrinology, Shandong Academy of Clinical Medicine, Jinan, China.,Shandong Clinical Medical Center of Endocrinology and Metabolism, Jinan, China
| | - Xiuyun Jiang
- Department of Endocrinology and Metabolism, Shandong Provincial Hospital, Cheeloo College of Medicine, Shandong University, Jinan, China.,Department of Endocrinology and Metabolism, Shandong Provincial Hospital Affiliated to Shandong First Medical University, Jinan, China.,Institute of Endocrinology, Shandong Academy of Clinical Medicine, Jinan, China.,Shandong Clinical Medical Center of Endocrinology and Metabolism, Jinan, China
| | - Jiajun Zhao
- Department of Endocrinology and Metabolism, Shandong Provincial Hospital, Cheeloo College of Medicine, Shandong University, Jinan, China.,Department of Endocrinology and Metabolism, Shandong Provincial Hospital Affiliated to Shandong First Medical University, Jinan, China.,Institute of Endocrinology, Shandong Academy of Clinical Medicine, Jinan, China.,Shandong Clinical Medical Center of Endocrinology and Metabolism, Jinan, China
| | - Yanzhou Wang
- Department of Pediatric Orthopedics, Shandong Provincial Hospital Affiliated to Shandong First Medical University, Jinan, China
| | - Chao Xu
- Department of Endocrinology and Metabolism, Shandong Provincial Hospital, Cheeloo College of Medicine, Shandong University, Jinan, China.,Department of Endocrinology and Metabolism, Shandong Provincial Hospital Affiliated to Shandong First Medical University, Jinan, China.,Institute of Endocrinology, Shandong Academy of Clinical Medicine, Jinan, China.,Shandong Clinical Medical Center of Endocrinology and Metabolism, Jinan, China
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2
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Chen Q, Wu SN, Chen YX, C SK, Zhang L, Wei HY, Kumar SA. A novel missense COL10A1 mutation: c.2020G>A; p. Gly674Arg linked with the bowed legs stature in the Schmid metaphyseal chondrodysplasia-affected Chinese lineage. Bone Rep 2019; 12:100240. [PMID: 31921940 PMCID: PMC6950639 DOI: 10.1016/j.bonr.2019.100240] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/27/2019] [Revised: 12/09/2019] [Accepted: 12/12/2019] [Indexed: 11/22/2022] Open
Abstract
To evaluate the clinical-phenotypic characteristics of Schmid metaphyseal chondrodysplasia (SMCD) inflicted by a novel missense mutation of COL10A1 gene: c.2020G > A; p.Gly674Arg. A female child aged about 3 yrs. and 8 months was subjected to Radiograph test to validate the symptoms of SMCD. The polymorphism analysis by the next-generation sequencing (NGS) was performed using the peripheral blood DNA samples of the patient and other family inmates, including, the younger male sibling. The effect of the mutation on the non-collagenous carboxyl-terminal (NC1) domain of collagen X was studied using the SWISS-MODEL online server for trimer modelling; PROSA and PROCHECK-Ramachandran plot for structural validation; Mean Square Plot (RMSF) for structural rigidity. Radiograph examination of lower limbs confirmed the bowed legs in both the patient and her younger brother (study groups). The inheritance of the novel missense mutation of COL10A1: c.2020G > A; p.Gly674Arg (at chromosome-6q22.1) was confirmed in the study groups from the SMCD-affected mother. The extended interactions of the mutant-Arg674 with the Ser552 and Phe589 (β strand B) in the NC1 domain of α1(X) chain monomer is more likely to intervene its trimer formation by weakening the structural rigidity of the crucial strand H compared to its wild type. This plausibly deters the collagen X synthesis inflicting the bowed legs with the altered distal ulna bone morphology in the study groups. The inheritance of COL10A1 mutation: c.2020G > A; p.Gly674Arg has inflicted the SMCD with the characteristic bowed legs in the study groups. Radiograph and NGS could be a valid diagnostic module to initiate the treatment of SMCD. A novel missense COL10A1 mutation (c.2020G>A; p.Gly674Arg) of NC1 domain of collagen X preceding Schmid Metaphyseal Chondrodysplasia. COL10A1 mutation (p.Gly674Arg) and the disturbed trimer structure of α1(X) chain monomer of collagen X. COL10A1 mutation (p.Gly674Arg) and the reduced rigidity of α1(X) chain monomer of collagen X. The mutated NC1 domain of collagen X structure and the bowed legs stature. Cupping and fraying of the distal ulna bone regulated by the weakened rigidity of the α1(X) chain monomer of collagen X.
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Affiliation(s)
- Qiong Chen
- Department of Endocrinology and Metabolism, Henan provincial key laboratory of children's genetics and metabolic diseases, Henan children's hospital (Children's hospital affiliated to Zhengzhou University), No-33, Longhu Waihuan East road, Zhengzhou 450018, China
| | - Sheng-Nan Wu
- Department of Endocrinology and Metabolism, Henan provincial key laboratory of children's genetics and metabolic diseases, Henan children's hospital (Children's hospital affiliated to Zhengzhou University), No-33, Longhu Waihuan East road, Zhengzhou 450018, China
| | - Yong-Xing Chen
- Department of Endocrinology and Metabolism, Henan provincial key laboratory of children's genetics and metabolic diseases, Henan children's hospital (Children's hospital affiliated to Zhengzhou University), No-33, Longhu Waihuan East road, Zhengzhou 450018, China
| | - Selvaa Kumar C
- School of Biotechnology and Bioinformatics, D. Y. Patil Deemed to be University, Sector-15, CBD Belapur, Navi Mumbai 400614, India
| | - Lu Zhang
- Shanghai We-Health Biomedical Technology Co. Ltd, Shanghai 201315, China
| | - Hai-Yan Wei
- Department of Endocrinology and Metabolism, Henan provincial key laboratory of children's genetics and metabolic diseases, Henan children's hospital (Children's hospital affiliated to Zhengzhou University), No-33, Longhu Waihuan East road, Zhengzhou 450018, China
| | - Senthil Arun Kumar
- Department of Endocrinology and Metabolism, Henan provincial key laboratory of children's genetics and metabolic diseases, Henan children's hospital (Children's hospital affiliated to Zhengzhou University), No-33, Longhu Waihuan East road, Zhengzhou 450018, China
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3
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Boot-Handford RP. Gene cloning to clinical trials-the trials and tribulations of a life with collagen. Int J Exp Pathol 2019; 100:4-11. [PMID: 30912609 DOI: 10.1111/iep.12311] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2018] [Revised: 02/19/2019] [Accepted: 02/24/2019] [Indexed: 12/17/2022] Open
Abstract
This review, based on the BSMB Fell-Muir Lecture I presented in July 2018 at the Matrix Biology Europe Conference in Manchester, gives a personal perspective of my own laboratory's contributions to research into type X collagen, metaphyseal chondrodysplasia type Schmid and potential treatments for this disorder that are currently entering clinical trial. I have tried to set the advances made in the context of the scientific technologies available at the time and how these have changed over the more than three decades of this research.
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Affiliation(s)
- Raymond P Boot-Handford
- Wellcome Centre for Cell-Matrix Research, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, UK
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4
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Park H, Hong S, Cho SI, Cho TJ, Choi IH, Jin DK, Sohn YB, Park SW, Cho HH, Cheon JE, Kim SY, Kim JY, Park SS, Seong MW. Case of mild Schmid-type metaphyseal chondrodysplasia with novel sequence variation involving an unusual mutational site of the COL10A1 gene. Eur J Med Genet 2015; 58:175-9. [DOI: 10.1016/j.ejmg.2014.12.011] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2014] [Accepted: 12/04/2014] [Indexed: 10/24/2022]
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5
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Lu Y, Qiao L, Lei G, Mira RR, Gu J, Zheng Q. Col10a1 gene expression and chondrocyte hypertrophy during skeletal development and disease. ACTA ACUST UNITED AC 2014. [DOI: 10.1007/s11515-014-1310-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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6
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The unfolded protein response and its relevance to connective tissue diseases. Cell Tissue Res 2009; 339:197-211. [PMID: 19851784 PMCID: PMC2784867 DOI: 10.1007/s00441-009-0877-8] [Citation(s) in RCA: 98] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2009] [Accepted: 09/03/2009] [Indexed: 12/13/2022]
Abstract
The unfolded protein response (UPR) has evolved to counter the stresses that occur in the endoplasmic reticulum (ER) as a result of misfolded proteins. This sophisticated quality control system attempts to restore homeostasis through the action of a number of different pathways that are coordinated in the first instance by the ER stress-senor proteins IRE1, ATF6 and PERK. However, prolonged ER-stress-related UPR can have detrimental effects on cell function and, in the longer term, may induce apoptosis. Connective tissue cells such as fibroblasts, osteoblasts and chondrocytes synthesise and secrete large quantities of proteins and mutations in many of these gene products give rise to heritable disorders of connective tissues. Until recently, these mutant gene products were thought to exert their effect through the assembly of a defective extracellular matrix that ultimately disrupted tissue structure and function. However, it is now becoming clear that ER stress and UPR, because of the expression of a mutant gene product, is not only a feature of, but may be a key mediator in the initiation and progression of a whole range of different connective tissue diseases. This review focuses on ER stress and the UPR that characterises an increasing number of connective tissue diseases and highlights novel therapeutic opportunities that may arise.
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7
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Ho MSP, Tsang KY, Lo RLK, Susic M, Mäkitie O, Chan TWY, Ng VCW, Sillence DO, Boot-Handford RP, Gibson G, Cheung KMC, Cole WG, Cheah KSE, Chan D. COL10A1 nonsense and frame-shift mutations have a gain-of-function effect on the growth plate in human and mouse metaphyseal chondrodysplasia type Schmid. Hum Mol Genet 2007; 16:1201-15. [PMID: 17403716 DOI: 10.1093/hmg/ddm067] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Missense, nonsense and frame-shift mutations in the collagen X gene (COL10A1) result in metaphyseal chondrodysplasia type Schmid (MCDS). Complete degradation of mutant COL10A1 mRNA by nonsense-mediated decay in human MCDS cartilage implicates haploinsufficiency in the pathogenesis for nonsense mutations in vivo. However, the mechanism is unclear in situations where the mutant mRNA persist. We show that nonsense/frame-shift mutations can elicit a gain-of-function effect, affecting chondrocyte differentiation in the growth plate. In an MCDS proband, heterozygous for a p.Y663X nonsense mutation, the growth plate cartilage contained 64% wild-type and 36% mutant mRNA and the hypertrophic zone was disorganized and expanded. The in vitro translated mutant collagen X chains, which are truncated, were misfolded, unable to assemble into trimers and interfered with the assembly of normal alpha1(X) chains into trimers. Unlike Col10a1 null mutants, transgenic mice (FCdel) bearing the mouse equivalent of a human MCDS p.P620fsX621 mutation, displayed typical characteristics of MCDS with disproportionate shortening of limbs and early onset coxa vara. In FCdel mice, the degree of expansion of the hypertrophic zones was transgene-dosage dependent, being most severe in mice homozygous for the transgene. Chondrocytes in the lower region of the expanded hypertrophic zone expressed markers uncharacteristic of hypertrophic chondrocytes, indicating that differentiation was disrupted. Misfolded FCdel alpha1(X) chains were retained within the endoplasmic reticulum of hypertrophic chondrocytes, activating the unfolded protein response. Our findings provide strong in vivo evidence for a gain-of-function effect that is linked to the activation of endoplasmic reticulum-stress response and altered chondrocyte differentiation, as a possible molecular pathogenesis for MCDS.
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Affiliation(s)
- Matthew S P Ho
- Department of Biochemistry, The University of Hong Kong, Pokfulam, Hong Kong, China
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8
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Bateman JF, Wilson R, Freddi S, Lamandé SR, Savarirayan R. Mutations of COL10A1 in Schmid metaphyseal chondrodysplasia. Hum Mutat 2006; 25:525-34. [PMID: 15880705 DOI: 10.1002/humu.20183] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Schmid metaphyseal chondrodysplasia (SMCD) is a dominantly inherited cartilage disorder caused by mutations in the gene for the hypertrophic cartilage extracellular matrix structural protein, collagen X (COL10A1). Thirty heterozygous mutations have been described, about equally divided into two mutation types, missense mutations, and mutations that introduce premature termination signals. The COL10A1 mutations are clustered (33/36) in the 3' region of exon 3, which codes for the C-terminal NC1 trimerization domain. The effect of COL10A1 missense mutations have been examined by in vitro expression and assembly assays and cell transfection studies, which suggest that a common consequence is the disruption of collagen X trimerization and secretion, with consequent intracellular degradation. The effect of COL10A1 nonsense mutations in cartilage tissue has been examined in two patients, demonstrating that the mutant mRNA is completely removed by nonsense mediated mRNA decay. Thus for both classes of mutations, functional haploinsufficiency is the most probable cause of the clinical phenotype in SMCD.
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Affiliation(s)
- John F Bateman
- Murdoch Childrens Research Institute, Department of Paediatrics, University of Melbourne, Royal Children's Hospital, Parkville, Victoria, Australia.
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9
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Young AE, Ryun JR, Bannasch DL. Deletions in the COL10A1 gene are not associated with skeletal changes in dogs. Mamm Genome 2006; 17:761-8. [PMID: 16845471 DOI: 10.1007/s00335-005-0163-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2005] [Accepted: 03/02/2006] [Indexed: 12/31/2022]
Abstract
Type 10 collagen alpha 1 (COL10A1) is a short-chain collagen of cartilage synthesized by chondrocytes during the growth of long bones. COL10A1 mutations, which frequently result in COL10A1 haploinsufficiency, have been identified in patients with Schmid metaphyseal chondrodysplasia (SMCD), a cartilage disorder characterized by short-limbed short stature and bowed legs. Similarities between SMCD and short stature in various dog breeds suggested COL10A1 as a candidate for canine skeletal dysplasia. We report the sequencing of the exons and promoter region of the COL10A1 gene in dog breeds fixed for a specific type of skeletal dysplasia known as chondrodysplasia, breeds that segregate the skeletal dysplasia phenotype, and control dogs of normal stature. Thirteen single nucleotide polymorphisms (SNPs), one insertion, and two deletions, one of which introduces a premature stop codon and likely results in nonsense-mediated decay and the degradation of the mutant allele product, were identified in the coding region. There appear to be no causal relationships between the polymorphisms identified in this study and short stature in dogs. Although COL10A1 haploinsufficiency is an important cause of SMCD in humans, it does not seem to be responsible for the skeletal dysplasia phenotype in these dog breeds. In addition, homozygosity for the nonsense allele does not result in the observed canine skeletal dysplasia phenotype.
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Affiliation(s)
- Amy E Young
- Department of Population Health and Reproduction, University of California-Davis, School of Veterinary Medicine, 1114 Tupper Hall, 1 Shields Avenue, 95616, USA.
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10
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Wilson R, Freddi S, Chan D, Cheah KSE, Bateman JF. Misfolding of collagen X chains harboring Schmid metaphyseal chondrodysplasia mutations results in aberrant disulfide bond formation, intracellular retention, and activation of the unfolded protein response. J Biol Chem 2005; 280:15544-52. [PMID: 15695517 DOI: 10.1074/jbc.m410758200] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Collagen X is a short chain collagen expressed specifically by the hypertrophic chondrocytes of the cartilage growth plate during endochondral bone formation. Accordingly, COL10A1 mutations disrupt growth plate function and cause Schmid metaphyseal chondrodysplasia (SMCD). SMCD mutations are almost exclusively located in the NC1 domain, which is crucial for both trimer formation and extracellular assembly. Several mutations are expected to reduce the level of functional collagen X due to NC1 domain misfolding or exclusion from stable trimer formation. However, other mutations may be tolerated within the structure of the assembled NC1 trimer, allowing mutant chains to exert a dominant-negative impact within the extracellular matrix. To address this, we engineered SMCD mutations that are predicted either to prohibit subunit folding and assembly (NC1del10 and Y598D, respectively) or to allow trimerization (N617K and G618V) and transfected these constructs into 293-EBNA and SaOS-2 cells. Although expected to form stable trimers, G618V and N617K chains (like Y598D and NC1del10 chains) were secreted very poorly compared with wild-type collagen X. Interestingly, all mutations resulted in formation of an unusual SDS-stable dimer, which dissociated upon reduction. As the NC1 domain sulfhydryl group is not solvent-exposed in the correctly folded NC1 monomer, disulfide bond formation would result only from a dramatic conformational change. In cells expressing mutant collagen X, we detected significantly increased amounts of the spliced form of X-box DNA-binding protein mRNA and up-regulation of BiP, two key markers for the unfolded protein response. Our data provide the first clear evidence for misfolding of SMCD collagen X mutants, and we propose that solvent exposure of the NC1 thiol may trigger the recognition and degradation of mutant collagen X chains.
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Affiliation(s)
- Richard Wilson
- Cell and Matrix Biology Research Unit, Murdoch Children's Research Institute, University of Melbourne, Royal Children's Hospital, Parkville, Victoria 3052, Australia
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11
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Huxley-Jones J, Robertson DL, Boot-Handford RP. The molecular evolution of the collagen X (C1q/TNFα) supergene family. Int J Exp Pathol 2004. [DOI: 10.1111/j.0959-9673.2004.0390z.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
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12
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Boudko SP, Engel J. Structure formation in the C terminus of type III collagen guides disulfide cross-linking. J Mol Biol 2004; 335:1289-97. [PMID: 14729344 DOI: 10.1016/j.jmb.2003.11.054] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
In type III collagen the main triple-helical domain is followed by a disulfide knot and the C-terminal propeptide, which are both essential for nucleation, stabilization and registration of the triple helix. We demonstrate that oxidative inter-chain disulfide bridging does not occur between the knot sequences GlyProCysCysGly of dissociated randomly coiled chains. N-terminal fusion of the obligatory trimeric domain of mini-fibritin is able to direct this process efficiently, demonstrating a folded precursor mechanism in which the thiol groups have to be properly placed for the formation of native disulfide bonds. The natural C-propeptide domain may act in a similar way as the mini-fibritin domain. After disulfide linkage and triple-helix formation the catalyzing mini-fibritin domain was removed by thrombin cleavage. In this way a short but stable triple-helical collagen fragment was expressed in Escherichia coli for structural and functional studies.
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Affiliation(s)
- Sergei P Boudko
- Biozentrum, University of Basel, Klingelbergstr 70, CH-4056 Basel, Switzerland
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13
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McAlinden A, Smith TA, Sandell LJ, Ficheux D, Parry DAD, Hulmes DJS. Alpha-helical coiled-coil oligomerization domains are almost ubiquitous in the collagen superfamily. J Biol Chem 2003; 278:42200-7. [PMID: 12920133 DOI: 10.1074/jbc.m302429200] [Citation(s) in RCA: 61] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Alpha-helical coiled-coils are widely occurring protein oligomerization motifs. Here we show that most members of the collagen superfamily contain short, repeating heptad sequences typical of coiled coils. Such sequences are found at the N-terminal ends of the C-propeptide domains in all fibrillar procollagens. When fused C-terminal to a reporter molecule containing a collagen-like sequence that does not spontaneously trimerize, the C-propeptide heptad repeats induced trimerization. C-terminal heptad repeats were also found in the oligomerization domains of the multiplexins (collagens XV and XVIII). N-terminal heptad repeats are known to drive trimerization in transmembrane collagens, whereas fibril-associated collagens with interrupted triple helices, as well as collagens VII, XIII, XXIII, and XXV, were found to contain heptad repeats between collagen domains. Finally, heptad repeats were found in the von Willebrand factor A domains known to be involved in trimerization of collagen VI, as well as in collagen VII. These observations suggest that coiled-coil oligomerization domains are widely used in the assembly of collagens and collagen-like proteins.
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Affiliation(s)
- Audrey McAlinden
- Department of Orthopedic Surgery, Washington University School of Medicine, Barnes-Jewish Hospital, St. Louis, MO 63110, USA
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14
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Hayward C, Shu X, Cideciyan AV, Lennon A, Barran P, Zareparsi S, Sawyer L, Hendry G, Dhillon B, Milam AH, Luthert PJ, Swaroop A, Hastie ND, Jacobson SG, Wright AF. Mutation in a short-chain collagen gene, CTRP5, results in extracellular deposit formation in late-onset retinal degeneration: a genetic model for age-related macular degeneration. Hum Mol Genet 2003; 12:2657-67. [PMID: 12944416 DOI: 10.1093/hmg/ddg289] [Citation(s) in RCA: 136] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
A primary feature of age-related macular degeneration (AMD) is the presence of extracellular deposits between the retinal pigment epithelium (RPE) and underlying Bruch's membrane, leading to RPE dysfunction, photoreceptor death and severe visual loss. AMD accounts for about 50% of blind registrations in Western countries and is a common, genetically complex disorder. Very little is known regarding its molecular basis. Late-onset retinal degeneration (L-ORD) is an autosomal dominant disorder with striking clinical and pathological similarity to AMD. Here we show that L-ORD is genetically heterogeneous and that a proposed founder mutation in the CTRP5 (C1QTNF5) gene, which encodes a novel short-chain collagen, changes a highly conserved serine to arginine (Ser163Arg) in 7/14 L-ORD families and 0/1000 control individuals. The mutation occurs in the gC1q domain of CTRP5 and results in abnormal high molecular weight aggregate formation which may alter its higher-order structure and interactions. These results indicate a novel disease mechanism involving abnormal adhesion between RPE and Bruch's membrane.
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Affiliation(s)
- Caroline Hayward
- MRC Human Genetics Unit, Western General Hospital, Edinburgh, UK
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15
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Waki H, Yamauchi T, Kamon J, Ito Y, Uchida S, Kita S, Hara K, Hada Y, Vasseur F, Froguel P, Kimura S, Nagai R, Kadowaki T. Impaired multimerization of human adiponectin mutants associated with diabetes. Molecular structure and multimer formation of adiponectin. J Biol Chem 2003; 278:40352-63. [PMID: 12878598 DOI: 10.1074/jbc.m300365200] [Citation(s) in RCA: 747] [Impact Index Per Article: 35.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Adiponectin is an adipocyte-derived hormone, which has been shown to play important roles in the regulation of glucose and lipid metabolism. Eight mutations in human adiponectin have been reported, some of which were significantly related to diabetes and hypoadiponectinemia, but the molecular mechanisms of decreased plasma levels and impaired action of adiponectin mutants were not clarified. Adiponectin structurally belongs to the complement 1q family and is known to form a characteristic homomultimer. Herein, we demonstrated that simple SDS-PAGE under non-reducing and non-heat-denaturing conditions clearly separates multimer species of adiponectin. Adiponectin in human or mouse serum and adiponectin expressed in NIH-3T3 or Escherichia coli formed a wide range of multimers from trimers to high molecular weight (HMW) multimers. A disulfide bond through an amino-terminal cysteine was required for the formation of multimers larger than a trimer. An amino-terminal Cys-Ser mutation, which could not form multimers larger than a trimer, abrogated the effect of adiponectin on the AMP-activated protein kinase pathway in hepatocytes. Among human adiponectin mutations, G84R and G90S mutants, which are associated with diabetes and hypoadiponectinemia, did not form HMW multimers. R112C and I164T mutants, which are associated with hypoadiponectinemia, did not assemble into trimers, resulting in impaired secretion from the cell. These data suggested impaired multimerization and/or the consequent impaired secretion to be among the causes of a diabetic phenotype or hypoadiponectinemia in subjects having these mutations. In conclusion, not only total concentrations, but also multimer distribution should always be considered in the interpretation of plasma adiponectin levels in health as well as various disease states.
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Affiliation(s)
- Hironori Waki
- Department of Internal Medicine, Graduate School of Medicine, University of Tokyo, Tokyo, 113-8655, Japan
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16
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Zheng Q, Zhou G, Morello R, Chen Y, Garcia-Rojas X, Lee B. Type X collagen gene regulation by Runx2 contributes directly to its hypertrophic chondrocyte-specific expression in vivo. J Cell Biol 2003; 162:833-42. [PMID: 12952936 PMCID: PMC2172833 DOI: 10.1083/jcb.200211089] [Citation(s) in RCA: 247] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
The alpha1(X) collagen gene (Col10a1) is the only known hypertrophic chondrocyte-specific molecular marker. Until recently, few transcriptional factors specifying its tissue-specific expression have been identified. We show here that a 4-kb murine Col10a1 promoter can drive beta-galactosidase expression in lower hypertrophic chondrocytes in transgenic mice. Comparative genomic analysis revealed multiple Runx2 (Runt domain transcription factor) binding sites within the proximal human, mouse, and chick Col10a1 promoters. In vitro transfection studies and chromatin immunoprecipitation analysis using hypertrophic MCT cells showed that Runx2 contributes to the transactivation of this promoter via its conserved Runx2 binding sites. When the 4-kb Col10a1 promoter transgene was bred onto a Runx2(+/-) background, the reporter was expressed at lower levels. Moreover, decreased Col10a1 expression and altered chondrocyte hypertrophy was also observed in Runx2 heterozygote mice, whereas Col10a1 was barely detectable in Runx2-null mice. Together, these data suggest that Col10a1 is a direct transcriptional target of Runx2 during chondrogenesis.
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Affiliation(s)
- Qiping Zheng
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
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17
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Zhang RZ, Sabatelli P, Pan TC, Squarzoni S, Mattioli E, Bertini E, Pepe G, Chu ML. Effects on collagen VI mRNA stability and microfibrillar assembly of three COL6A2 mutations in two families with Ullrich congenital muscular dystrophy. J Biol Chem 2002; 277:43557-64. [PMID: 12218063 DOI: 10.1074/jbc.m207696200] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
We recently reported a severe deficiency in collagen type VI, resulting from recessive mutations of the COL6A2 gene, in patients with Ullrich congenital muscular dystrophy. Their parents, who are all carriers of one mutant allele, are unaffected, although heterozygous mutations in collagen VI caused Bethlem myopathy. Here we investigated the consequences of three COL6A2 mutations in fibroblasts from patients and their parents in two Ullrich families. All three mutations lead to nonsense-mediated mRNA decay. However, very low levels of undegraded mutant mRNA remained in patient B with compound heterozygous mutations at the distal part of the triple-helical domain, resulting in deposition of abnormal microfibrils that cannot form extensive networks. This observation suggests that the C-terminal globular domain is not essential for triple-helix formation but is critical for microfibrillar assembly. In all parents, the COL6A2 mRNA levels are reduced to 57-73% of the control, but long term collagen VI matrix depositions are comparable with that of the control. The almost complete absence of abnormal protein and near-normal accumulation of microfibrils in the parents may account for their lack of myopathic symptoms.
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Affiliation(s)
- Rui-Zhu Zhang
- Department of Dermatology and Cutaneous Biology, Thomas Jefferson University, Philadelphia, Pennsylvania 19107, USA
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18
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Wilson R, Freddi S, Bateman JF. Collagen X chains harboring Schmid metaphyseal chondrodysplasia NC1 domain mutations are selectively retained and degraded in stably transfected cells. J Biol Chem 2002; 277:12516-24. [PMID: 11805116 DOI: 10.1074/jbc.m112044200] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Collagen X is a short chain, homotrimeric collagen expressed specifically by hypertrophic chondrocytes during endochondral bone formation and growth. Although the exact role of collagen X remains unresolved, mutations in the COL10A1 gene disrupt growth plate function and result in Schmid metaphyseal chondrodysplasia (SMCD). With the exception of two mutations that impair signal peptide cleavage during alpha1(X) chain biosynthesis, SMCD mutations are clustered within the carboxyl-terminal NC1 domain. The formation of stable NC1 domain trimers is a critical stage in collagen X assembly, suggesting that mutations within this domain may result in subunit mis-folding or reduce trimer stability. When expressed in transiently transfected cells, alpha1(X) chains containing SMCD mutations were unstable and presumed to be degraded intracellularly. More recently, in vitro studies have shown that certain missense mutations may exert a dominant negative effect on alpha1(X) chain assembly by formation of mutant homotrimers and normal-mutant heterotrimers. In contrast, analysis of cartilage tissue from two SMCD patients revealed that the truncated mutant message was fully degraded, resulting in 50% reduction of functional collagen X within the growth plate. Therefore, in the absence of data that conclusively demonstrates the full cellular response to mutant collagen X chains, the molecular mechanisms underlying SMCD remain controversial. To address this, we closely examined the effect of two NC1 domain mutations, one frameshift mutation (1963del10) and one missense mutation (Y598D), using both semi-permeabilized cell and stable cell transfection expression systems. Although able to assemble to a limited extent in both systems, we show that, in intact cells, collagen X chains harboring both SMCD mutations did not evade quality control mechanisms within the secretory pathway and were degraded intracellularly. Furthermore, co-expression of wild-type and mutant chains in stable transfected cells demonstrated that, although wild-type chains were secreted, mutant chains were largely excluded from hetero-trimer formation. Our data indicate, therefore, that the predominant effect of the NC1 mutations Y598D and 1963del10 is a reduction in the amount of functional collagen X within the growth cartilage extracellular matrix.
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Affiliation(s)
- Richard Wilson
- Cell & Matrix Biology Research Unit, Department of Paediatrics, University of Melbourne, Parkville, Victoria 3052, Australia
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19
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Bogin O, Kvansakul M, Rom E, Singer J, Yayon A, Hohenester E. Insight into Schmid metaphyseal chondrodysplasia from the crystal structure of the collagen X NC1 domain trimer. Structure 2002; 10:165-73. [PMID: 11839302 DOI: 10.1016/s0969-2126(02)00697-4] [Citation(s) in RCA: 91] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Collagen X is expressed specifically in the growth plate of long bones. Its C1q-like C-terminal NC1 domain forms a stable homotrimer and is crucial for collagen X assembly. Mutations in the NC1 domain cause Schmid metaphyseal chondrodysplasia (SMCD). The crystal structure at 2.0 A resolution of the human collagen X NC1 domain reveals an intimate trimeric assembly strengthened by a buried cluster of calcium ions. Three strips of exposed aromatic residues on the surface of NC1 trimer are likely to be involved in the supramolecular assembly of collagen X. Most internal SMCD mutations probably prevent protein folding, whereas mutations of surface residues may affect the collagen X suprastructure in a dominant-negative manner.
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Affiliation(s)
- Oren Bogin
- ProChon Biotech, P.O. Box 1482, Rehovot 76114, Israel
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20
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Abstract
Two chains, alpha1(VIII) and alpha2(VIII), have been described for type VIII collagen. Early work suggested that these chains were present in a 2:1 ratio, although recent work has shown that homotrimers can form and predominate in some tissues. In order to address the question of whether the alpha1(VIII) and alpha2(VIII) chains could co-polymerise we made a shortened alpha1(VIII) chain and expressed this with full length alpha2(VIII) chain in an in vitro translation system supplemented with semi-permeabilised cells. Heterotrimers containing either two or one alpha2(VIII) were evident. Interestingly, a point mutation in the NC1 domain of the alpha1(VIII) chain abrogated trimer formation. In addition we were able to demonstrate chain association of the alpha1(X) chain of type X collagen with the shortened alpha1(VIII) chain. Variations in chain association were seen when altered ratios of message were used. These results demonstrate the importance of the NC1 domain in chain association and suggest that gene expression regulates the composition and function of type VIII collagen by varying chain composition.
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Affiliation(s)
- C Illidge
- University of Manchester, Wellcome Trust Center for Cell/Matrix Research, 2.205 Stopford Building, Oxford Rd, M13 9PT, Manchester, UK
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21
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Chan D, Ho MS, Cheah KS. Aberrant signal peptide cleavage of collagen X in Schmid metaphyseal chondrodysplasia. Implications for the molecular basis of the disease. J Biol Chem 2001; 276:7992-7. [PMID: 11115494 DOI: 10.1074/jbc.m003361200] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Schmid metaphyseal chondrodysplasia results from mutations in the collagen X (COL10A1) gene. With the exception of two cases, the known mutations are clustered in the C-terminal nonhelical (NC1) domain of the collagen X. In vitro and cell culture studies have shown that the NC1 mutations result in impaired collagen X trimer assembly and secretion. In the two other cases, missense mutations that alter Gly(18) at the -1 position of the putative signal peptide cleavage site were identified (Ikegawa, S., Nakamura, K., Nagano, A., Haga, N., and Nakamura, Y. (1997) Hum. Mutat. 9, 131-135). To study their impact on collagen X biosynthesis using in vitro cell-free translation in the presence of microsomes, and cell transfection assays, these two mutations were created in COL10A1 by site-directed mutagenesis. The data suggest that translocation of the mutant pre-alpha1(X) chains into the microsomes is not affected, but cleavage of the signal peptide is inhibited, and the mutant chains remain anchored to the membrane of microsomes. Cell-free translation and transfection studies in cells showed that the mutant chains associate into trimers but cannot form a triple helix. The combined effect of both the lack of signal peptide cleavage and helical configuration is impaired secretion. Thus, despite the different nature of the NC1 and signal peptide mutations in collagen X, both result in impaired collagen X secretion, probably followed by intracellular retention and degradation of mutant chains, and causing the Schmid metaphyseal chondrodysplasia phenotype.
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Affiliation(s)
- D Chan
- Department of Biochemistry, University of Hong Kong, Hong Kong SAR, China.
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22
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Abstract
Early development of the vertebrate skeleton depends on genes that pattern the distribution and proliferation of cells from cranial neural crest, sclerotomes, and lateral plate mesoderm into mesenchymal condensations at sites of future skeletal elements. Within these condensations, cells differentiate to chondrocytes or osteoblasts and form cartilages and bones under the control of various transcription factors. In most of the skeleton, organogenesis results in cartilage models of future bones; in these models cartilage is replaced by bone by the process of endochondral ossification. Lastly, through a controlled process of bone growth and remodeling the final skeleton is shaped and molded. Significant and exciting insights into all aspects of vertebrate skeletal development have been obtained through molecular and genetic studies of animal models and humans with inherited disorders of skeletal morphogenesis, organogenesis, and growth.
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Affiliation(s)
- B R Olsen
- Harvard Medical School, Department of Cell Biology, 240 Longwood Avenue, Boston, Massachusetts 02115, USA.
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23
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Ball SG, Baldock C, Kielty CM, Shuttleworth CA. The role of the C1 and C2 a-domains in type VI collagen assembly. J Biol Chem 2001; 276:7422-30. [PMID: 11036066 DOI: 10.1074/jbc.m002816200] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Constructs of each of the three chains of type VI collagen were generated and examined in an in vitro transcription/translation assay supplemented with semipermeabilized cells. Each of the constructs when used in the in vitro system was shown to be glycosylated and to undergo intracellular assembly, the extent of which was determined by the nature of the C-terminal globular domains. All three chains containing the C1 domain formed monomers; however, the C2 domain was required for dimer and tetramer formation. In the case of the full-length alpha2(VI) chain, monomers, dimers, and tetramers formed in a time-dependent manner. Although the splice variant alpha2(VI)C2a could form monomers, it was unable to form dimers and tetramers. Similar results to the alpha2(VI) chain were found for the full-length alpha1(VI) chain, although assembly was at a slower rate. In the case of the alpha3(VI) chain containing both C1 and C2 domains only monomers were observed. Addition of the C3, C4, and C5 did not change this pattern. Homology modeling suggested that a 10-amino acid insertion in the C2 domain of the alpha3(VI) chain may interfere with dimer formation. A near full-length construct of the alpha3(VI) chain only formed monomers but was shown to facilitate tetramer formation in cotranslation experiments.
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Affiliation(s)
- S G Ball
- University of Manchester, School of Biological Sciences, Wellcome Trust Centre for Cell/Matrix Research, 2.205 Stopford, Manchester M13 9PT, United Kingdom
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24
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Koide T, Aso A, Yorihuzi T, Nagata K. Conformational requirements of collagenous peptides for recognition by the chaperone protein HSP47. J Biol Chem 2000; 275:27957-63. [PMID: 10862616 DOI: 10.1074/jbc.m003026200] [Citation(s) in RCA: 48] [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
The collagen binding chaperone HSP47 interacts with procollagen in the endoplasmic reticulum and plays a crucial role in the biosynthesis of collagen. We recently demonstrated that typical collagen model peptides, (Pro-Pro-Gly)(n), possess sufficient structural information for interaction with HSP47 (Koide, T., Asada, S., and Nagata, K. (1999) J. Biol. Chem. 274, 34523-34526). Here we show that binding of (Gly-Pro-Pro)(n) peptides to HSP47 can be detected using the two-hybrid system in yeast if a trimerizing domain is fused to the C termini of the peptides. Some peptides interacted with HSP47 at a lowered assay temperature at 24 degrees C but not at 30 degrees C, indicating the importance of conformational change of the substrate peptides. To analyze the spectrum of HSP47 substrate sequences, we performed two-hybrid screening of collagen-like peptides in designed random peptide libraries using HSP47 as a bait. In selected peptides, the enrichment ratio calculated for each amino acid residue correlated strongly with the contribution of the residue to triple-helix stability independently determined using synthetic collagen model peptides. Taken together, our results suggest that HSP47 preferentially recognizes collagenous Gly-X-Y repeats in triple-helical conformation. We also demonstrated that screening of combinatorial peptide libraries is a powerful strategy to determine conformational requirements as well as the elucidation of binding motifs in primary structure.
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Affiliation(s)
- T Koide
- Core Research for Evolutional Science and Technology (CREST), Japan
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25
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Mongiat M, Mungiguerra G, Bot S, Mucignat MT, Giacomello E, Doliana R, Colombatti A. Self-assembly and supramolecular organization of EMILIN. J Biol Chem 2000; 275:25471-80. [PMID: 10821830 DOI: 10.1074/jbc.m001426200] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The primary structure of human Elastin microfibril interface-located protein (EMILIN), an elastic fiber-associated glycoprotein, consists of a globular C1q domain (gC1q) at the C terminus, a short collagenous stalk, a long region with a high potential for forming coiled-coil alpha helices, and a cysteine-rich N-terminal sequence. It is not known whether the EMILIN gC1q domain is involved in the assembly process and in the supramolecular organization as shown for the similar domain of collagen X. By employing the yeast two-hybrid system the EMILIN gC1q domains interacted with themselves, proving for the first time that this interaction occurs in vivo. The gC1q domain formed oligomers running as trimers in native gels that were less stable than the comparable trimers of the collagen X gC1q domain since they did not withstand heating. The collagenous domain was trypsin-resistant and migrated at a size corresponding to a triple helix under native conditions. In reducing agarose gels, EMILIN also migrated as a trimer, whereas under non-reducing conditions it formed polymers of many millions of daltons. A truncated fragment lacking gC1q and collagenous domains assembled to a much lesser extent, thus deducing that the C-terminal domain(s) are essential for the formation of trimers that finally assemble into large EMILIN multimers.
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Affiliation(s)
- M Mongiat
- Divisione di Oncologia Sperimentale 2, Centro di Riferimento Oncologico di Aviano, Italy
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26
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Colombatti A, Doliana R, Bot S, Canton A, Mongiat M, Mungiguerra G, Paron-Cilli S, Spessotto P. The EMILIN protein family. Matrix Biol 2000; 19:289-301. [PMID: 10963989 DOI: 10.1016/s0945-053x(00)00074-3] [Citation(s) in RCA: 78] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
The EMILINs are a new family of glycoproteins of the extracellular matrix. The prototype of this family is the chicken EMILIN that was originally identified in extracts of aortas; it was then found to be widely distributed in several tissues associated with elastin and localized at the interface between amorphous elastin and microfibrils. Based on peptide sequences, chicken and human cDNAs coding for EMILIN were isolated by RT/PCR by screening kidney and heart cDNA libraries. By using a C-terminal fragment of human EMILIN-1 as a bait in the yeast two-hybrid system, a second family member, EMILIN-2, has also been isolated. EMILINs are characterized by a C-terminal gC1q globular domain, a short collagenous sequence, a long coiled-coil region and a new cysteine-rich N-terminal domain that can be considered a hallmark of the family being present also in multimerin. The gene for EMILIN-1 was mapped on chromosome 2p23 overlapping with the promoter region of the ketohexokinase gene. The gC1q domain of EMILIN-1 can form relatively stable and compact homotrimers and this association is then followed by a multimeric assembly of disulfide-bonded protomers. Recombinant EMILIN-1 purified from the supernatant of 293 cells represents a very efficient ligand for cell adhesion of several cell types.
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Affiliation(s)
- A Colombatti
- Divisione di Oncologia Sperimentale 2, CRO-IRCCS, 33081, Aviano,
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27
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Sasaki T, Hohenester E, Zhang RZ, Gotta S, Speer MC, Tandan R, Timpl R, Chu ML. A Bethlem myopathy Gly to Glu mutation in the von Willebrand factor A domain N2 of the collagen alpha3(VI) chain interferes with protein folding. FASEB J 2000; 14:761-8. [PMID: 10744632 DOI: 10.1096/fasebj.14.5.761] [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: 11/11/2022]
Abstract
A single G1679E mutation in the amino-terminal globular domain N2 of the alpha3 chain of type VI collagen was found in a large family affected with Bethlem myopathy. Recombinant production of N2 ( approximately 200 residues) in transfected mammalian cells has now been used to examine the possibility that the mutation interfered with protein folding. The wild-type form and a G1679A mutant were produced at high levels and shown to fold into a stable globular structure. Only a small amount of secretion was observed for mutants G1679E and G1679Q, which apparently were efficiently degraded within the cells. Homology modeling onto the related von Willebrand factor A1 structure indicated that substitution of G1679 by the bulky E or Q cannot be accommodated without considerable changes in the folding pattern. This suggests protein misfolding as a molecular basis for this particular mutation in Bethlem myopathy, in agreement with radioimmunoassay data showing reduced levels of domain N2 in cultured fibroblasts from two patients.
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Affiliation(s)
- T Sasaki
- Max-Planck-Institut für Biochemie, D-82152 Martinsried, Germany
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