The Experts below are selected from a list of 1470 Experts worldwide ranked by ideXlab platform
Annamarja Saamanen - One of the best experts on this subject based on the ideXlab platform.
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the Fibril Associated Collagen ix provides a novel mechanism for cell adhesion to cartilaginous matrix
Journal of Biological Chemistry, 2004Co-Authors: Jarmo Käpylä, Juha Jaalinoja, Mira Tulla, Joni H Ylostalo, Liisa Nissinen, Tiina Viitasalo, Piia Vehvilainen, Varpu Marjomaki, Petri Nykvist, Annamarja SaamanenAbstract:Abstract Collagen IX is the prototype Fibril-Associated Collagen with interruptions in triple helix. In human cartilage it covers Collagen Fibrils, but its putative cellular receptors have been unknown. The reverse transcription-PCR analysis of human fetal tissues suggested that based on their distribution all four Collagen receptor integrins, namely α1β1, α2β1, α10β1, and α11β1, are possible receptors for Collagen IX. Furthermore primary chondrocytes and chondrosarcoma cells express the four integrins simultaneously. Chondrosarcoma cells, as well as Chinese hamster ovary cells transfected to express α1β1, α2β1, or α10β1 integrin as their only Collagen receptor, showed fast attachment and spreading on human recombinant Collagen IX indicating that it is an effective cell adhesion protein. To further study the recognition of Collagen IX we produced recombinant αI domains in Escherichia coli. For each of the four αI domains, Collagen IX was among the best Collagenous ligands, making Collagen IX exceptional compared with all other Collagen subtypes tested so far. Rotary shadowing electron microscopy images of both α1I- and α2I-Collagen IX complexes unveiled only one binding site located in the COL3 domain close to the kink between it and the COL2 domain. The recognition of Collagen IX by α2I was considered to represent a novel mechanism for two reasons. First, Collagen IX has no GFOGER motif, and the identified binding region lacks any similar sequences. Second, the α2I domain mutations D219R and H258V, which both decreased binding to Collagen I and GFOGER, had very different effects on its binding to Collagen IX. D219R had no effect, and H258V prevented type IX binding. Thus, our results indicate that Collagen IX has unique cell adhesion properties when compared with other Collagens, and it provides a novel mechanism for cell adhesion to cartilaginous matrix.
Susanne Grassel - One of the best experts on this subject based on the ideXlab platform.
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discrete integration of Collagen xvi into tissue specific Collagen Fibrils or beaded microFibrils
Matrix Biology, 2003Co-Authors: Anja Kassner, Uwe Hansen, Nicolai Miosge, Dieter P Reinhardt, Thomas Aigner, Leena Brucknertuderman, Peter Bruckner, Susanne GrasselAbstract:The structural and functional diversity of extracellular matrices is determined, not only by individual macromolecules, but even more decisively, by the alloyed aggregates they form. Although quantitatively major matrix molecules can occur ubiquitously, their organization varies from one tissue to another due to their amalgamation with specific sets of minor components. Here, we show that the Fibril-Associated Collagen with interrupted triple helices Collagen XVI is unique in that, depending on the tissue context, it can be incorporated into distinct suprastructural aggregates. In papillary dermis, the protein unexpectedly does not occur in banded Collagen Fibrils, but rather, is a component of specialized Fibrillin-1-containing microFibrils. In territorial cartilage matrix, however, Collagen XVI is not a component of aggregates containing Fibrillin-1. Instead, the protein resides in a discrete population of thin, weakly banded Collagen Fibrils also containing Collagens II and XI. Collagen IX also occurs in this population of Fibrils, but at longitudinal locations discrete from those of Collagen XVI. This suprastructural versatility of a Collagen is without precedent and highlights pivotal differences in the tissue-specific organization of matrix aggregate structures.
Thomas F. Linsenmayer - One of the best experts on this subject based on the ideXlab platform.
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Collagen Fibril assembly in the developing avian primary corneal stroma
Investigative Ophthalmology & Visual Science, 1994Co-Authors: John M Fitch, C M Linsenmayer, Thomas F. LinsenmayerAbstract:Purpose. The primary stroma of the developing avian cornea is a highly organized extracellular matrix composed largely of striated Collagen Fibrils synthesized by the epithelium. These Fibrils are heterotypic structures consisting of at least two different Fibrillar Collagen types (I and II) and probably a Fibril-Associated Collagen (type IX). The epithelial derivation and vectorial secretion of the components of this matrix provide an advantageous system to study the steps in the assembly of this developmentally regulated matrix, as well as in the assembly and maturation of heterotypic Collagen Fibrils in general
Detlef Schuppan - One of the best experts on this subject based on the ideXlab platform.
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a chondroitin dermatan sulfate form of cd44 is a receptor for Collagen xiv undulin
Experimental Cell Research, 1996Co-Authors: Tobias Ehnis, Walburga Dieterich, Michael Bauer, Bernd Von Lampe, Detlef SchuppanAbstract:Collagen XIV, a Fibril-Associated Collagen with interrupted triple helices, is expressed in differentiated soft connective tissues and in cartilage. However, a cellular receptor for this protein has not been identified. Here we show that human placental Collagen XIV, isolated by a mild and simple two-step method, serves as adhesive protein for a variety of mesenchymal and some epithelial cells. Cell adhesion could be inhibited by preincubation of the Collagen XIV substrate with heparin or with the chondroitin/dermatan sulfate proteoglycan decorin and by pretreatment of cells with chondroitinase ABC or heparinase III, suggesting a cell membrane proteoglycan as receptor. Affinity chromatography of125I-labeled fibroblast cell surface proteins on Collagen XIV–Sepharose yielded a chondroitin/dermatan sulfate proteoglycan with a molecular mass of 97–105 kDa after chondroitinase ABC digestion and of 60–70 kDa after further treatment withN-glycosidase F. The eluates contained also some high-molecular-weight material that was susceptible to digestion with heparinase but no detectable integrins. Immunoprecipitation with a specific monoclonal antibody identified the prominent chondroitin/dermatan sulfate proteoglycan as a member of the CD44 family. The interaction between Collagen XIV and cells appears to be finely tuned, since matrix-Associated glycosaminoglycans, and particularly proteoglycans like decorin, could compete with cells for the binding site(s) on Collagen XIV under physiological conditions.
Manuel Koch - One of the best experts on this subject based on the ideXlab platform.
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Collagen XIV is important for growth and structural integrity of the myocardium
2015Co-Authors: Ge Tao, Manuel Koch, Agata K. Levay, Jacqueline D. Peacock, Danielle J. Huk, Sarah N. Bothb, Nicole H. Purcell, Jose R. Pinto, Maarten L. Galantowicz, Pamela A. LucchesiAbstract:Collagen XIV is a Fibril-Associated Collagen with an interrupted triple helix (FACIT). Previous studies have shown that this Collagen type regulates early stages of Fibrillogenesis in connective tissues of high mechanical demand. Mice null for Collagen XIV are viable, however formation of the interstitial Collagen network is defective in tendons and skin leading to reduced biomechanical function. The assembly of a tightly regulated Collagen network is also required in the heart, not only for structural support but also for controlling cellular processes. Collagen XIV is highly expressed in the embryonic heart, notably within the cardiac interstitium of the developing myocardium, however its role has not been elucidated. To test this, we examined cardiac phenotypes in embryonic and adult mice devoid of Collagen XIV. From as early as E11.5, Col14a1−/ − mice exhibit significant perturbations in mRNA levels of many other Collagen type
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type xiv Collagen regulates Fibrillogenesis premature Collagen Fibril growth and tissue dysfunction in null mice
Journal of Biological Chemistry, 2009Co-Authors: Heather L Ansorge, Xianmin Meng, Guido Veit, David P Beason, Manuel Koch, John F Klement, Guiyun Zhang, Louis J. Soslowsky, David E BirkAbstract:Type XIV Collagen is a Fibril-Associated Collagen with an interrupted triple helix. This Collagen interacts with the Fibril surface and has been implicated as a regulator of Fibrillogenesis; however, a specific role has not been elucidated. Functional roles for type XIV Collagen were defined utilizing a new type XIV Collagen-deficient mouse line. This line was produced using a conventional targeted knock-out approach. Col14a1(–/–) mice were devoid of type XIV Collagen, whereas heterozygous mice had reduced synthesis. Both mutant Col14a1 genotypes were viable with a grossly normal phenotype; however, mature skin exhibited altered mechanical properties. Prior to evaluating tendon Fibrillogenesis in type XIV Collagen-deficient mice, the developmental expression patterns were analyzed in wild-type flexor digitorum longus (FDL) tendons. Analyses of mRNA and protein expression indicated tissue-specific temporal expression that was Associated with the early stages in Fibrillogenesis. Ultrastructural analyses of wild-type and null tendons demonstrated premature Fibril growth and larger Fibril diameters in tendons from null mice at postnatal day 4 (P4). However, Fibril structure in mature tendons was normal. Biomechanical studies established a direct structure/function relationship with reduced strength in P7-null tendons. However, the biomechanical properties in P60 tendons were comparable in null and wild-type mice. Our results indicate a regulatory function for type XIV Collagen in early stages of Collagen Fibrillogenesis with tissue differences.