The Experts below are selected from a list of 285 Experts worldwide ranked by ideXlab platform
Richard William Farndale - One of the best experts on this subject based on the ideXlab platform.
-
an activating mutation reveals a second binding mode of the integrin α2 i domain to the gfoger motif in Collagens
PLOS ONE, 2013Co-Authors: Federico Carafoli, Dominique Bihan, Samir W Hamaia, Erhard Hohenester, Richard William FarndaleAbstract:The GFOGER motif in Collagens (O denotes hydroxyproline) represents a high-affinity binding site for all Collagen-binding integrins. Other GxOGER motifs require integrin activation for maximal binding. The E318W mutant of the integrin α2β1 I domain displays a relaxed Collagen specificity, typical of an active state. E318W binds more strongly than the wild-type α2 I domain to GMOGER, and forms a 2:1 complex with a homotrimeric, Collagen-like, GFOGER peptide. Crystal structure analysis of this complex reveals two E318W I domains, A and B, bound to a single triple helix. The E318W I domains are virtually identical to the Collagen-bound wild-type I domain, suggesting that the E318W mutation activates the I domain by destabilising the unligated conformation. E318W I domain A interacts with two Collagen chains similarly to wild-type I domain (high-affinity mode). E318W I domain B makes favourable interactions with only one Collagen chain (low-affinity mode). This observation suggests that single GxOGER motifs in the heterotrimeric Collagens V and IX may support binding of activated integrins.
-
Collagen binding specificity of the discoidin domain receptors binding sites on Collagens ii and iii and molecular determinants for Collagen iv recognition by ddr1
Matrix Biology, 2011Co-Authors: Huifang Xu, Nicolas Raynal, Stavros Stathopoulos, Richard William Farndale, Johanna Myllyharju, Birgit LeitingerAbstract:The discoidin domain receptors, DDR1 and DDR2 are cell surface receptor tyrosine kinases that are activated by triple-helical Collagen. While normal DDR signalling regulates fundamental cellular processes, aberrant DDR signalling is associated with several human diseases. We previously identified GVMGFO (O is hydroxyproline) as a major DDR2 binding site in Collagens I–III, and located two additional DDR2 binding sites in Collagen II. Here we extend these studies to the homologous DDR1 and the identification of DDR binding sites on Collagen III. Using sets of overlapping triple-helical peptides, the Collagen II and Collagen III Toolkits, we located several DDR2 binding sites on both Collagens. The interaction of DDR1 with Toolkit peptides was more restricted, with DDR1 mainly binding to peptides containing the GVMGFO motif. Triple-helical peptides containing the GVMGFO motif induced DDR1 transmembrane signalling, and DDR1 binding and receptor activation occurred with the same amino acid requirements as previously defined for DDR2. While both DDRs exhibit the same specificity for binding the GVMGFO motif, which is present only in fibrillar Collagens, the two receptors display distinct preferences for certain non-fibrillar Collagens, with the basement membrane Collagen IV being exclusively recognised by DDR1. Based on our recent crystal structure of a DDR2-Collagen complex, we designed mutations to identify the molecular determinants for DDR1 binding to Collagen IV. By replacing five amino acids in DDR2 with the corresponding DDR1 residues we were able to create a DDR2 construct that could function as a Collagen IV receptor.
-
first analysis of a bacterial Collagen binding protein with Collagen toolkits promiscuous binding of yada to Collagens may explain how yada interferes with host processes
Infection and Immunity, 2010Co-Authors: Heli Elovaara, Nicolas Raynal, Dominique Bihan, Nicholas Pugh, Sami K Kilpinen, Richard William Farndale, Mikael Skurnik, Adrian GoldmanAbstract:The Yersinia adhesin YadA mediates the adhesion of the human enteropathogen Yersinia enterocolitica to Collagens and other components of the extracellular matrix. Though YadA has been proposed to bind to a specific site in Collagens, the exact binding determinants for YadA in native Collagen have not previously been elucidated. We investigated the binding of YadA to Collagen Toolkits, which are libraries of triple-helical peptides spanning the sequences of type II and III human Collagens. YadA bound to many of them, in particular to peptides rich in hydroxyproline but with few charged residues. We were able to block the binding of YadA to Collagen type IV with the triple-helical peptide (Pro-Hyp-Gly)10, suggesting that the same site in YadA binds to triple-helical regions in network-forming Collagens as well. We showed that a single Gly-Pro-Hyp triplet in a triple-helical peptide was sufficient to support YadA binding, but more than six triplets were required to form a tight YadA binding site. This is significantly longer than the case for eukaryotic Collagen-binding proteins. YadA-expressing bacteria bound promiscuously to Toolkit peptides. Promiscuous binding could be advantageous for pathogenicity in Y. enterocolitica and, indeed, for other pathogenic bacteria. Many of the tightly binding peptides are also targets for eukaryotic Collagen-binding proteins, and YadA was able to inhibit the interaction between selected Toolkit peptides and platelets. This leads to the intriguing possibility that YadA may interfere in vivo with host processes mediated by endogenous Collagen-binding proteins.
-
α11β1 integrin recognizes the gfoger sequence in interstitial Collagens
Journal of Biological Chemistry, 2003Co-Authors: Wanming Zhang, Carlfredrik Tiger, Jarmo Kapyla, Santeri J Puranen, Graham C Knight, Olli T Pentikainen, Richard William Farndale, Jyrki Heino, Mark Johnson, Donald GullbergAbstract:Abstract The integrins α1β1, α2β1, α10β1, and α11β1 are referred to as a Collagen receptor subgroup of the integrin family. Recently, both α1β1 and α2β1integrins have been shown to recognize triple-helical GFOGER (where single letter amino acid nomenclature is used, O = hydroxyproline) or GFOGER-like motifs found in Collagens, despite their distinct binding specificity for various Collagen subtypes. In the present study we have investigated the mechanism whereby the latest member in the integrin family, α11β1, recognizes Collagens using C2C12 cells transfected with α11 cDNA and the bacterially expressed recombinant α11 I domain. The ligand binding properties of α11β1 were compared with those of α2β1. Mg2+-dependent α11β1 binding to type I Collagen required micromolar Ca2+ but was inhibited by 1 mmCa2+, whereas α2β1-mediated binding was refractory to millimolar concentrations of Ca2+. The bacterially expressed recombinant α11 I domain preference for fibrillar Collagens over Collagens IV and VI was the same as the α2 I domain. Despite the difference in Ca2+ sensitivity, α11β1-expressing cells and the α11 I domain bound to helical GFOGER sequences in a manner similar to α2β1-expressing cells and the α2 I domain. Modeling of the α I domain-Collagen peptide complexes could partially explain the observed preference of different I domains for certain GFOGER sequence variations. In summary, our data indicate that the GFOGER sequence in fibrillar Collagens is a common recognition motif used by α1β1, α2β1, and also α11β1 integrins. Although α10and α11 chains show the highest sequence identity, α2 and α11 are more similar with regard to Collagen specificity. Future studies will reveal whether α2β1 and α11β1integrins also show overlapping biological functions.
-
the Collagen binding a domains of integrins alpha 1 beta 1 and alpha 2 beta 1 recognize the same specific amino acid sequence gfoger in native triple helical Collagens
Journal of Biological Chemistry, 2000Co-Authors: Graham C Knight, Laurence F Morton, Anthony R Peachey, Danny S Tuckwell, Richard William Farndale, M. BarnesAbstract:Abstract We have previously assigned an integrin α2β1-recognition site in Collagen I to the sequence, GFOGERGVEGPOGPA (O = Hyp), corresponding to residues 502–516 of the α1(I) chain and located in the fragment α1(I)CB3 (Knight, C. G., Morton, L. F., Onley, D. J., Peachey, A. R., Messent, A. J., Smethurst, P. A., Tuckwell, D. S., Farndale, R. W., and Barnes, M. J. (1998) J. Biol. Chem. 273, 33287–33294). In this study, we show that recognition is entirely contained within the six-residue sequence GFOGER. This sequence, when in triple-helical conformation, readily supports α2β1-dependent cell adhesion and exhibits divalent cation-dependent binding of isolated α2β1 and recombinant α2A-domain, being at least as active as the parent Collagen. Replacement of E by D causes loss of recognition. The same sequence binds integrin α1 A-domain and supports integrin α1β1-mediated cell adhesion. Triple-helical GFOGER completely inhibits α2 A-domain binding to Collagens I and IV and α2β1-dependent adhesion of platelets and HT 1080 cells to these Collagens. It also fully inhibits α1 A-domain binding to Collagen I and strongly inhibits α1β1-mediated adhesion of Rugli cells to this Collagen but has little effect on either α1 A-domain binding or adhesion of Rugli cells to Collagen IV. We conclude that the sequence GFOGER represents a high-affinity binding site in Collagens I and IV for α2β1 and in Collagen I for α1β1. Other high-affinity sites in Collagen IV mediate its recognition of α1β1.
Michael S Yu - One of the best experts on this subject based on the ideXlab platform.
-
targeting and mimicking Collagens via triple helical peptide assembly
Current Opinion in Chemical Biology, 2013Co-Authors: Yang Li, Michael S YuAbstract:As the major structural component of the extracellular matrix, Collagen plays a crucial role in tissue development and regeneration. Since structural and metabolic abnormalities of Collagen are associated with numerous debilitating diseases and pathologic conditions, the ability to target Collagens of diseased tissues could lead to new diagnostics and therapeutics. Collagen is also a natural biomaterial widely used in drug delivery and tissue engineering, and construction of synthetic Collagen-like materials is gaining interests in the biomaterials community. The unique triple helical structure of Collagen has been explored for targeting Collagen strands, and for engineering Collagen-like functional assemblies and conjugates. This review focuses on the forefront of research activities in the use of the Collagen mimetic peptide for both targeting and mimicking Collagens via its triple helix mediated strand hybridization and higher order assembly.
John J. Robinson - One of the best experts on this subject based on the ideXlab platform.
-
comparative biochemical analysis of sea urchin peristome and rat tail tendon Collagen
Comparative Biochemistry and Physiology B, 1997Co-Authors: John J. RobinsonAbstract:Abstract We report here a biochemical comparison between type I rat tail tendon Collagen and Collagen isolated from sea urchin peristome tissue. The sea urchin Collagen consisted of two species of apparent mol masses, 140 and 116 kDa. Amino acid compositional analysis of the 140 and 116 kDa species revealed the presence of hydroxyproline and hydroxylysine as well as a glycine content of 28.1 mol.%. In solubility experiments the rat tail tendon Collagen was found to precipitate at sodium chloride concentrations between 1 and 2 M while peristome Collagen remained soluble at salt concentrations as high as 4 M. Incubation of the peristome and rat tail tendon Collagen preparations with a sea urchin Collagenase/gelatinase resulted in cleavage of the former but not the latter Collagen. Upon heat denaturation at 60°C, however, the rat tail tendon Collagen served as a substrate for the gelatinase. Cyanogen bromide cleavage of rat tail and peristome Collagens generated largely unique peptide maps. Collectively, these results suggest that structural differences exist between echinoderm and vertebrate type 1 Collagens.
John R Baker - One of the best experts on this subject based on the ideXlab platform.
-
isolation and characterization of the chains of type v type xi Collagen present in bovine vitreous
Journal of Biological Chemistry, 1993Co-Authors: Richard Mayne, Randolph G Brewton, P M Mayne, John R BakerAbstract:Abstract Previous studies show that the Collagen fibrils of the mammalian vitreous humor are assembled largely from type II Collagen with smaller amounts of type IX Collagen and either type V or type XI Collagen. In this paper, we report the separation of two chains of type V/type XI Collagen from type II Collagen by heparin-Sepharose chromatography. These chains were characterized by sequencing of selected cyanogen bromide or tryptic peptides with subsequent comparison of these sequences with cDNA-derived amino acid sequences of the alpha 1(V), alpha 1(XI), alpha 2(V), and alpha 2(XI) chains. The results show that vitreous fibrils are assembled from molecules containing the alpha 1(XI) and alpha 2(V) chains. These results, together with recent results from other laboratories, indicate that type V and type XI Collagens are not separate Collagen types but are part of a larger Collagen family in which chains of both type V and type XI Collagens participate in the formation of a variety of native molecules.
Raili Myllyla - One of the best experts on this subject based on the ideXlab platform.
-
secretion and assembly of type iv and vi Collagens depend on glycosylation of hydroxylysines
Journal of Biological Chemistry, 2007Co-Authors: Laura Sipila, Heli Ruotsalainen, Raija Sormunen, Naomi L Baker, Shireen R Lamande, Miia Vapola, Chunguang Wang, Attila Aszodi, Yoshikazu Sado, Raili MyllylaAbstract:Abstract Most lysines in type IV and VI Collagens are hydroxylated and glycosylated, but the functions of these unique galactosylhydroxylysyl and glucosylgalactosylhydroxylysyl residues are poorly understood. The formation of glycosylated hydroxylysines is catalyzed by multifunctional lysyl hydroxylase 3 (LH3) in vivo, and we have used LH3-manipulated mice and cells as models to study the function of these carbohydrates. These hydroxylysine-linked carbohydrates were shown recently to be indispensable for the formation of basement membranes (Ruotsalainen, H., Sipila, L., Vapola, M., Sormunen, R., Salo, A. M., Uitto, L., Mercer, D. K., Robins, S. P., Risteli, M., Aszodi, A., Fassler, R., and Myllyla, R. (2006) J. Cell Sci. 119, 625–635). Analysis of LH3 knock-out embryos and cells in this work indicated that loss of glycosylated hydroxylysines prevents the intracellular tetramerization of type VI Collagen and leads to impaired secretion of type IV and VI Collagens. Mice lacking the LH activity of LH3 produced slightly underglycosylated type IV and VI Collagens with abnormal distribution. The altered distribution and aggregation of type VI Collagen led to similar ultrastructural alterations in muscle to those detected in Collagen VI knockout and some Ullrich congenital muscular dystrophy patients. Our results provide new information about the function of hydroxylysine-linked carbohydrates of Collagens, indicating that they play an important role in the secretion, assembly, and distribution of highly glycosylated Collagen types.