Browse
Submit Data
Databases
API
Help

Dataset Information

8 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

Structure of a collagen VI α3 chain VWA domain array: adaptability and functional implications of myopathy causing mutations.

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.

SUBMITTER: Solomon-Degefa H

PROVIDER: S-EPMC7476709 | biostudies-literature |

REPOSITORIES: biostudies-literature

ACCESS DATA

Json Xml

Similar Datasets

Aberrant mitochondria in a Bethlem myopathy patient with a homozygous amino acid substitution that destabilizes the collagen VI α2(VI) chain.

Project description:Bethlem myopathy and Ullrich congenital muscular dystrophy (UCMD) sit at opposite ends of a clinical spectrum caused by mutations in the extracellular matrix protein collagen VI. Bethlem myopathy is relatively mild, and patients remain ambulant in adulthood while many UCMD patients lose ambulation by their teenage years and require respiratory interventions. Dominant and recessive mutations are found across the entire clinical spectrum; however, recessive Bethlem myopathy is rare, and our understanding of the molecular pathology is limited. We studied a patient with Bethlem myopathy. Electron microscopy of his muscle biopsy revealed abnormal mitochondria. We identified a homozygous COL6A2 p.D871N amino acid substitution in the C-terminal C2 A-domain. Mutant α2(VI) chains are unable to associate with α1(VI) and α3(VI) and are degraded by the proteasomal pathway. Some collagen VI is assembled, albeit more slowly than normal, and is secreted. These molecules contain the minor α2(VI) C2a splice form that has an alternative C terminus that does include the mutation. Collagen VI tetramers containing the α2(VI) C2a chain do not assemble efficiently into microfibrils and there is a severe collagen VI deficiency in the extracellular matrix. We expressed wild-type and mutant α2(VI) C2 domains in mammalian cells and showed that while wild-type C2 domains are efficiently secreted, the mutant p.D871N domain is retained in the cell. These studies shed new light on the protein domains important for intracellular and extracellular collagen VI assembly and emphasize the importance of molecular investigations for families with collagen VI disorders to ensure accurate diagnosis and genetic counseling.

| S-EPMC4326835 | biostudies-literature

C-terminal proteolysis of the collagen VI α3 chain by BMP-1 and proprotein convertase(s) releases endotrophin in fragments of different sizes.

Project description:The assembly of collagen VI microfibrils is a multistep process in which proteolytic processing within the C-terminal globular region of the collagen VI α3 chain plays a major role. However, the mechanisms involved remain elusive. Moreover, C5, the short and most C-terminal domain of the α3 chain, recently has been proposed to be released as an adipokine that enhances tumor progression, fibrosis, inflammation, and insulin resistance and has been named "endotrophin." Serum endotrophin could be a useful biomarker to monitor the progression of such disorders as chronic obstructive pulmonary disease, systemic sclerosis, and kidney diseases. Here, using biochemical and isotopic MS-based analyses, we found that the extracellular metalloproteinase bone morphogenetic protein 1 (BMP-1) is involved in endotrophin release and determined the exact BMP-1 cleavage site. Moreover, we provide evidence that several endotrophin-containing fragments are present in various tissues and body fluids. Among these, a large C2-C5 fragment, which contained endotrophin, was released by furin-like proprotein convertase cleavage. By using immunofluorescence microscopy and EM, we also demonstrate that these proteolytic maturations occur after secretion of collagen VI tetramers and during microfibril assembly. Differential localization of N- and C-terminal regions of the collagen VI α3 chain revealed that cleavage products are deposited in tissue and cell cultures. The detailed information on the processing of the collagen VI α3 chain reported here provides a basis for unraveling the function of endotrophin (C5) and larger endotrophin-containing fragments and for refining their use as biomarkers of disease progression.

| S-EPMC6746452 | biostudies-literature

Defective collagen VI α6 chain expression in the skeletal muscle of patients with collagen VI-related myopathies.

Project description:Collagen VI is a non-fibrillar collagen present in the extracellular matrix (ECM) as a complex polymer; the mainly expressed form is composed of α1, α2 and α3 chains; mutations in genes encoding these chains cause myopathies known as Ullrich congenital muscular dystrophy (UCMD), Bethlem myopathy (BM) and myosclerosis myopathy (MM). The collagen VI α6 chain is a recently identified component of the ECM of the human skeletal muscle. Here we report that the α6 chain was dramatically reduced in skeletal muscle and muscle cell cultures of genetically characterized UCMD, BM and MM patients, independently of the clinical phenotype, the gene involved and the effect of the mutation on the expression of the "classical" α1α2α3 heterotrimer. By contrast, the collagen VI α6 chain was normally expressed or increased in the muscle of patients affected by other forms of muscular dystrophy, the overexpression matching with areas of increased fibrosis. In vitro treatment with TGF-β1, a potent collagen inducer, promoted the collagen VI α6 chain deposition in the ECM of normal muscle cells, whereas, in cultures derived from collagen VI-related myopathy patients, the collagen VI α6 chain failed to develop a network outside the cells and accumulated in the endoplasmic reticulum. The defect of the α6 chain points to a contribution to the pathogenesis of collagen VI-related disorders.

| S-EPMC4316388 | biostudies-literature

The collagen VI-related myopathies Ullrich congenital muscular dystrophy and Bethlem myopathy.

Project description:Mutations in the genes COL6A1, COL6A2, and COL6A3, coding for three ? chains of collagen type VI, underlie a spectrum of myopathies, ranging from the severe congenital muscular dystrophy-type Ullrich (UCMD) to the milder Bethlem myopathy (BM), with disease manifestations of intermediate severity in between. UCMD is characterized by early-onset weakness, associated with pronounced distal joint hyperlaxity and the early onset or early progression of more proximal contractures. In the most severe cases ambulation is not achieved, or it may be achieved only for a limited period of time. BM may be of early or later onset, but is milder in its manifestations, typically allowing for ambulation well into adulthood, whereas typical joint contractures are frequently prominent. A genetic spectrum is emerging, with BM being caused mostly by dominantly acting mutations, although rarely recessive inheritance of BM is also possible, whereas both dominantly as well as recessively acting mutations underlie UCMD.

| S-EPMC5207779 | biostudies-literature

Clinical, Pathologic, and Genetic Features of Collagen VI-Related Myopathy in Korea.

Project description:Background and purposeMutations in collagen VI-related genes (COL6A1, COL6A2, and COL6A3) cause Bethlem myopathy (BM) and Ullrich congenital muscular dystrophy (UCMD). These were previously believed to be separate disease entities, but they are now both classified as collagen VI-related myopathies, which cover a broad clinical spectrum. We aimed to analyze the clinical, pathologic, and genetic characteristics of patients with collagen VI-related myopathy in Korea.MethodsWe reviewed the clinical, pathologic, and genetic features in 22 patients with collagen VI-related myopathy from 13 families, as confirmed by genetic analysis of collagen VI-related genes.ResultsThe mean ages of the 22 patients at first symptom presentation and diagnosis were 4.5 and 24.9 years, respectively. Four patients in 4 families showed the phenotype of intermediate collagen VI-related myopathies (IM), 16 patients in 7 families had the BM phenotype, and 2 patients in 2 families presented with the typical UCMD phenotype. Based on genetic analysis, five patients (five families) comprising four with IM and one with typical UCMD had missense mutations in the triple-helical domain of COL6A1, and ten patients (four families) with BM showed exon-14-skipping mutations. Additionally, we found two novel mutations: c.956A>G (p.K319R) in COL6A1 and c.6221G>T (p.G2074V) in COL6A3.ConclusionsMissense mutations in the triple-helical domain of COL6A1 are the most common mutations related to collagen VI-related myopathy in Korea. Patients with these mutations have a tendency toward an earlier disease onset and more severe progression compared to patients with other mutations.

| S-EPMC5653620 | biostudies-literature

A structure of a collagen VI VWA domain displays N and C termini at opposite sides of the protein.

Project description: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.

| S-EPMC3919171 | biostudies-literature

Use of RNA‑sequencing to detect abnormal transcription of the collagen α‑2 (VI) chain gene that can lead to Bethlem myopathy.

Project description:Bethlem myopathy (BM) is an autosomal dominant or autosomal recessive disorder and is usually associated with mutations in the collagen VI genes. In the present study, the pathogenicity of a novel splice‑site mutation was explored using RNA‑sequencing in a family with suspected BM, and a myopathy panel was performed in the proband. The genetic status of all family members was confirmed using Sanger sequencing. Clinical data and magnetic resonance imaging (MRI) features were also documented. In silico analysis was performed to predict the effects of the splice mutation. RNA‑sequencing and reverse transcription (RT)‑PCR were used to assess aberrant splicing. Immunocytochemistry was conducted to measure collagen VI protein levels within the gastrocnemius and in cultured skin fibroblasts. The results revealed that three patients in the family shared a similar classic BM presentation. MRI revealed distinct patterns of fatty infiltration in the lower extremities. A novel splicing mutation c.736‑1G>C in the collagen α‑2 (VI) chain (COL6A2) gene was found in all three patients. In silico analysis predicted that the mutation would destroy the normal splice acceptor site. RNA‑sequencing detected two abnormal splicing variants adjacent to the mutation site, and RT‑PCR confirmed the RNA‑sequencing findings. Furthermore, a defect in the collagen protein within cultured fibroblasts was detected using immunocytochemistry. The mutation c.736‑1G>C in the COL6A2 gene caused aberrant splicing and led to premature termination of protein translation. In conclusion, these findings may improve our knowledge of mutations of the COL6A2 gene associated with BM and demonstrated that RNA‑sequencing can be a powerful tool for finding the underlying mechanism of a disease‑causing mutations at a splice site.

| S-EPMC7895517 | biostudies-literature

Project description:BackgroundScoliosis is a complex three-dimensional deformity of spine and one of the common complications of collagen VI-related myopathy, caused by mutations in collagen type VI alpha 1 chain (COL6A1), COL6A2, and COL6A3 genes. The typical clinical presentations of collagen VI-related myopathy include weakness, hypotonia, laxity of distal joints, contractures of proximal joints, and skeletal deformities.Case summaryA 28-year-old female presented with scoliosis for 28 years without weakness, hypotonia, laxity of distal joints, and contracture of proximal joints. Computed tomography and magnetic resonance imaging revealed hemivertebra, butterfly vertebra, and the missing vertebral space. Patients underwent orthopedic surgery and paravertebral muscle biopsy. The Cobb angle dropped from 103.4° to 52.9°. However, the muscle biopsy showed neurogenic muscular atrophy with myogenic lesions, suggesting congenital muscular dystrophy. Gene analysis indicated that mutations in COL6A1 (c.1612-10G>A) and COL6A2 (c.115+10G>T, c.2749G>A). Immunohistochemistry staining for collagen VI displayed shallow and discontinuous. Eventually, the patient was diagnosed as collagen VI-related myopathy.ConclusionThis newly found subtype of collagen VI-related myopathy has no typical manifestations; however, it is characterized by severe scoliosis and congenital vertebral deformity.

| S-EPMC8283577 | biostudies-literature

Intrafamilial Phenotypic Variability of Collagen VI-Related Myopathy Due to a New Mutation in the COL6A1 Gene.

Project description:A family of five male siblings (three survivors at 48, 53 and 58 years old; two deceased at 8 months old and 2.5 years old) demonstrating significant phenotypic variability ranging from intermediate to the myosclerotic like Bethlem myopathy is presented. Whole-exome sequencing (WES) identified a new homozygous missense mutation chr21:47402679 T > C in the canonical splice donor site of the second intron (c.227 + 2T>C) in the COL6A1 gene. mRNA analysis confirmed skipping of exon 2 encoding 925 amino-acids in 94-95% of resulting transcripts. Three sibs presented with intermediate phenotype of collagen VI-related dystrophies (48, 53 and 2.5 years old) while the fourth sibling (58 years old) was classified as Bethlem myopathy with spine rigidity. The two older siblings with the moderate progressive phenotype (48 and 53 years old) lost their ability to maintain a vertical posture caused by pronounced contractures of large joints, but continued to ambulate throughout life on fully bent legs without auxiliary means of support. Immunofluorescence analysis of dermal fibroblasts demonstrated that no type VI collagen was secreted in any of the siblings' cells, regardless of clinical manifestations severity while fibroblast proliferation and colony formation ability was decreased. The detailed genetic and long term clinical data contribute to broadening the genotypic and phenotypic spectrum of COL6A1 related disease.

| S-EPMC8075389 | biostudies-literature

New Clinical and Immunofluoresence Data of Collagen VI-Related Myopathy: A Single Center Cohort of 69 Patients.

Project description:Pathogenetic mechanism recognition and proof-of-concept clinical trials were performed in our patients affected by collagen VI-related myopathies. This study, which included 69 patients, aimed to identify innovative clinical data to better design future trials. Among the patients, 33 had Bethlem myopathy (BM), 24 had Ullrich congenital muscular dystrophy (UCMD), 7 had an intermediate phenotype (INTM), and five had myosclerosis myopathy (MM). We obtained data on muscle strength, the degree of contracture, immunofluorescence, and genetics. In our BM group, only one third had a knee extension strength greater than 50% of the predicted value, while only one in ten showed similar retention of elbow flexion. These findings should be considered when recruiting BM patients for future trials. All the MM patients had axial and limb contractures that limited both the flexion and extension ranges of motion, and a limitation in mouth opening. The immunofluorescence analysis of collagen VI in 55 biopsies from 37 patients confirmed the correlation between collagen VI defects and the severity of the clinical phenotype. However, biopsies from the same patient or from patients with the same mutation taken at different times showed a progressive increase in protein expression with age. The new finding of the time-dependent modulation of collagen VI expression should be considered in genetic correction trials.

| S-EPMC10420187 | biostudies-literature

OmicsDI is part of the ELIXIR infrastructure

OmicsDI is an Elixir interoperability service. Learn more ›

Tweets

OmicsDI Databases

PRIDE
PeptideAtlas
MassIVE
JPOST Repository
Physiome Model Repository

EGA
EVA
ENA
LINCS
PAXDB
Cell Collective

MetaboLights
Metabolomics Workbench
MetabolomeExpress
GNPS
BioModels
FAIRDOMHub

ArrayExpress
dbGaP
ExpressionAtlas
GEO
NODE

Information

Databases
Help
API
Contact us
Code on GitHub
Terms of use
Submit Data