Identification of binding partners interacting with the α1-N-propeptide of type V collagen (original) (raw)
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Journal of Biological Chemistry
The cause of the Ehlers-Danlos syndrome Type VII (EDS VII) is considered to be defective removal of the amino-terminal propeptide (N-propeptide) of Type I procollagen due to deficiency of procollagen N-proteinase, the enzyme responsible for the normal proteolytic excision of this precursor-specific domain. Molecules retaining the N-propeptide (pN-collagen molecules) are thought to cause defective fibrillogenesis and cross-linking which eventuate in dramatic joint laxity and joint dislocations, the clinical hallmark of this variety of EDS. Recent studies demonstrate that some EDS VII patients harbor small deletions of either the pro-alpha 1(I) or pro-alpha 2(I) chain of Type I procollagen. We have found an 18-amino acid deletion (due to exon outsplicing) in a mutant pro-alpha 2(I) chain from such a patient. The deleted peptide is the junctional segment (N-telopeptide) linking the alpha 2(I) N-propeptide and major triple helical domains; loss of this short segment results in union of ...
The Ehlers-Danlos syndrome: on beyond collagens
Journal of Clinical Investigation, 2001
The Ehlers-Danlos syndrome (EDS) is a clinically and genetically heterogeneous connective tissue disorder affecting as many as 1 in 5,000 individuals (1). EDS is characterized in its most common form by hyperextensibility of the skin, hypermobility of joints often resulting in dislocations, and tissue fragility exemplified by easy bruising, atrophic scars following superficial injury, and premature rupture of membranes during pregnancy. The recognition of frequent ultrastructural abnormalities of collagen fibrils in EDS patients led to the concept that EDS is a disorder of fibrillar collagen metabolism (2). Following the identification of specific mutations in the genes encoding collagen types I, III, and V, as well as several collagen processing enzymes, the EDS classification scheme was collapsed into six distinct clinical syndromes (3), emphasizing the molecular basis of each form (Table 1). Heterogeneity between the several clinical syndromes both complicates the diagnosis of EDS and makes accurate diagnosis imperative. Ultimately, one would like to be able to establish a molecular diagnosis for each EDS patient. This is a laudable goal because it may allow improved genetic counseling through correlation of mutant genotypes with specific outcomes or complications. However, as outlined below, the molecular defects described to date are not sufficient to explain disease in many EDS patients, including those with the most common classical and hypermobility types. As a result, the search for EDS genes recently has expanded beyond the collagens and collagen-modifying genes. An understanding of the complete complement of genes and proteins involved in EDS and the precise mechanisms by which they cause disease may teach us much about normal collagenous matrix deposition and remodeling. These processes are of critical importance during development, wound healing, and aging. Collagen metabolism and molecular mechanisms of EDS The concept that EDS is a disorder of fibrillar collagen metabolism is well supported by identification of specific defects in the collagen biosynthetic pathway that produce clinically distinct forms of EDS. These are briefly reviewed below and in Figure 1. For more complete reviews of collagen biochemistry and clinical aspects of EDS, the reader is directed to recent reviews (1, 2). There are three fundamental mechanisms of disease known to produce EDS: deficiency of collagen-processing enzymes, dominant-negative effects of mutant collagen α-chains, and haploinsufficiency. The two known examples of deficient enzyme activity leading to EDS are lysyl-hydroxylase deficiency and procollagen peptidase deficiency. In the first case, the inability to hydroxylate lysine residues precludes normal intermolecular cross-linking of collagen trimers, and in the second instance, absence of procollagen peptidase prevents normal proteolytic cleavage of the NH 2-terminus of procollagen chains. In both circumstances the morphology and strength of the collagen fibril is compromised (Figure 2b), explaining the severe and early clinical findings. Because half-normal enzyme activity is sufficient for normal collagen processing, both of these conditions are recessive. Dominant-negative mutations in collagen I, III, and V cause several different forms of EDS (Figure 1). The most clinically significant of these are COL3A1 mutations causing the potentially lethal vascular form of
Journal of Investigative Dermatology, 2008
Mutations in the genes encoding for type V collagen have been found in the classical type of Ehlers-Danlos syndrome (EDS); the most common mutations lead to a non-functional COL5A1 allele. We characterized three skin fibroblast strains derived from patients affected by classical EDS caused by COL5A1 haploinsufficiency. As a typical clinical hallmark of EDS is the impaired wound healing, we analyzed the repair capability of fibroblasts in a monolayer wounding assay. The mutant fibroblast strains were unable to move into the scraped area showing then a marked delay in wound repair. In all the EDS strains, type V collagen was absent in the extracellular space, also leading to the lack of fibronectin fibrillar network and impairing the expression of a 2 b 1 and a 5 b 1 integrins. The abnormal integrin pattern inhibited the positive effect of insulin-like growth factor-binding protein-1 on cell migration, whereas the migratory capability remarkably improved in the presence of exogenous type V collagen. These authors contributed equally to this work Abbreviations: ECM, extracellular matrix; EDS, Ehlers-Danlos syndrome; IGFBP-1, insulin-like growth factor-binding protein-1; RT-PCR, reversetranscription PCR Wenstrup RJ, Florer JB, Davidson JM, Phillips CL, Pfeiffer BJ, Menezes DW et al. (2006) Murine model of the Ehlers-Danlos syndrome: COL5A1 haploinsufficiency disrupts collagen fibril assembly at multiple stages. J Biol Chem 281:12888-95 Zoppi N, Gardella R, De Paepe A, Barlati S, Colombi M (2004) Human fibroblasts with mutations in COL5A1 and COL3A1 genes do not organize collagens and fibronectin in the extracellular matrix, downregulate alpha2beta1 integrin, and recruit alphavbeta3 instead of alpha5beta1 integrin.
PLOS ONE, 2019
Classical Ehlers-Danlos syndrome (cEDS) is a dominant inherited connective tissue disorder mainly caused by mutations in the COL5A1 and COL5A2 genes encoding type V collagen (COLLV), which is a fibrillar COLL widely distributed in a variety of connective tissues. cEDS patients suffer from skin hyperextensibility, abnormal wound healing/atrophic scars, and joint hypermobility. Most of the causative variants result in a non-functional COL5A1 allele and COLLV haploinsufficiency, whilst COL5A2 mutations affect its structural integrity. To shed light into disease mechanisms involved in cEDS, we performed gene expression profiling in skin fibroblasts from four patients harboring haploinsufficient and structural mutations in both disease genes. Transcriptome profiling revealed significant changes in the expression levels of different extracellular matrix (ECM)-related genes, such as SPP1, POSTN, EDIL3, IGFBP2, and C3, which encode both matricellular and soluble proteins that are mainly involved in cell proliferation and migration, and cutaneous wound healing. These gene expression changes are consistent with our previous protein findings on in vitro fibroblasts from other cEDS patients, which exhibited reduced migration and poor wound repair owing to COLLV disorganization, altered deposition of fibronectin into ECM, and an abnormal integrin pattern. Microarray analysis also indicated the decreased expression of DNAJB7, VIPAS39, CCPG1, ATG10, SVIP, which encode molecular chaperones facilitating protein folding, enzymes regulating post-Golgi COLLs processing, and proteins acting as cargo receptors required for endoplasmic reticulum (ER) proteostasis and implicated in the autophagy process. Patients' cells also showed altered mRNA levels of many cell cycle regulating genes including CCNE2, KIF4A, MKI67, DTL, and DDIAS. Protein studies showed that aberrant COLLV expression causes the disassembly of itself and many structural ECM constituents including COLLI, COLLIII, fibronectin, and fibrillins. Our findings provide the first molecular evidence of significant gene expression changes in cEDS skin fibroblasts highlighting that defective ECM remodeling, ER homeostasis and autophagy might play a role in the pathogenesis of this connective tissue disorder.
Biochimica et Biophysica Acta (BBA) - General Subjects, 2012
Background: Alternative splicing of EDA fibronectin (FN) region is a cell type-and development-regulated mechanism controlled by pathological processes, growth factors and extracellular matrix (ECM). Classic and vascular Ehlers-Danlos syndrome (cEDS and vEDS) are connective tissue disorders caused by COL5A1/ COL5A2 and COL3A1 gene mutations, leading to an in vivo abnormal collagen fibrillogenesis and to an in vitro defective organisation in the ECM of type V (COLLV) and type III collagen (COLLIII). These defects induce the FN-ECM disarray and the decrease of COLLs and FN receptors, the α2β1 and α5β1 integrins. Purified COLLV and COLLIII restore the COLL-FN-ECMs in both EDS cell strains. Methods: Real-time PCR, immunofluorescence microscopy, and Western blotting were used to investigate the effects of COLLs on FN1 gene expression, EDA region alternative splicing, EDA +-FN-ECM assembly, α5β1 integrin and EDA +-FN-specific α9 integrin subunit organisation, α5β1 integrin and FAK co-regulation in EDS fibroblasts. Results: COLLV-treated cEDS and COLLIII-treated vEDS fibroblasts up-regulate the FN1 gene expression, modulate the EDA + mRNA maturation and increase the EDA +-FN levels, thus restoring a control-like FN-ECM, which elicits the EDA +-FN-specific α9β1 integrin organisation, recruits the α5β1 integrin and switches on the FAK binding and phosphorylation. Conclusion: COLLs regulate the EDA +-FN-ECM organisation at transcriptional and post-transcriptional level and activate the α5β1-FAK complexes. COLLs also recruit the α9β1 integrin involved in the assembly of the EDA +-FN-ECM in EDS cells. General significance: The knowledge of the COLLs-ECM role in FN isotype expression and in EDA +-FN-ECMmediated signal transduction adds insights in the ECM remodelling mechanisms in EDS cells.
Human Mutation, 2009
Classic Ehlers-Danlos syndrome (EDS) is a heritable connective tissue disease characterized by skin hyperextensibility, atrophic scarring, joint hypermobility and generalized tissue fragility. Mutations in COL5A1 and COL5A2, encoding the type V collagen proα1-and proα2-chain, are found in ~50% of patients with classic EDS. The majority of mutations lead to a non-functional COL5A1 allele, as a result of the introduction of a premature stopcodon in one COL5A1 transcript. A minority of mutations affect the structure of the type V collagen central helical domain. We show that mutations in the signal peptide (SP) domain of the preproα1(V)-collagen chain cause classic EDS. The missense mutations (p.L25R and p.L25P) are located in the crucial hydrophobic SP core, which is indispensible for preprotein translocation into the endoplasmic reticulum. As a result, mutant type V procollagen is retained within the cell, leading to a decreased amount of type V collagen in the extracellular matrix and disturbed collagen fibrillogenesis. Our findings further support the observation that decreased availability of type V (pro)collagen is a key factor and a shared mechanism in the pathogenesis of classic EDS.
Classical Ehlers-Danlos Syndrome Caused by a Mutation in Type I Collagen
American Journal of Human Genetics, 2000
Classical Ehlers-Danlos syndrome (EDS) is characterized by skin hyperelasticity, joint hypermobility, increased tendency to bruise, and abnormal scarring. Mutations in type V collagen, a regulator of type I collagen fibrillogenesis, have been shown to underlie this type of EDS. However, to date, mutations have been found in only a limited number of patients, which suggests genetic heterogeneity. In this article, we report two unrelated patients with typical features of classical EDS, including excessive skin fragility, in whom we found an identical argininercysteine substitution in type I collagen, localized at position 134 of the a1(I) collagen chain. The arginine residue is highly conserved and localized in the X position of the Gly-X-Y triplet. As a consequence, intermolecular disulfide bridges are formed, resulting in type I collagen aggregates, which are retained in the cells. Whereas substitutions of glycine residues in type I collagen invariably result in osteogenesis imperfecta, substitutions of nonglycine residues in type I collagen have not yet been associated with a human disease. In contrast, argininercysteine substitutions in type II collagen have been identified in a variety of chondrodysplasias. Our findings show that mutations in other fibrillar collagens can be causally involved in classical EDS and point to genetic heterogeneity of this disorder.
Mutations in the COL5A1 gene are causal in the Ehlers-Danlos syndromes I and II
American journal of …, 1997
The Ehlers-Danlos syndrome (EDS) is a heterogeneous connective-tissue disorder of which at least nine subtypes are recognized. Considerable clinical overlap exists between the EDS I and II subtypes, suggesting that both are allelic disorders. Recent evidence based on linkage and transgenic mice studies suggest that collagen V is causally involved in human EDS. Collagen V forms heterotypic fibrils with collagen I in many tissues and plays an important role in collagen I fibrillogenesis. We have identified a mutation in COL5A1, the gene encoding the proal(V) collagen chain, segregating with EDS I in a four-generation family. The mutation causes the substitution of the most 5' cysteine residue by a serine within a highly conserved sequence of the proal(V) C-propeptide domain and causes reduction of collagen V by preventing incorporation of the mutant proal(V) chains in the collagen V trimers. In addition, we have detected splicing defects in the COL5A1 gene in a patient with EDS I and in a family with EDS II. These findings confirm the causal role of collagen V in at least a subgroup of EDS I, prove that EDS I and II are allelic conditions, and represent a, so far, unique example of a human collagen disorder caused by substitution of a highly conserved cysteine residue in the C-propeptide domain of a fibriliar collagen.