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| 2. |
- Lundell, Anna, et al.
(författare)
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Structural basis for interactions between tenascins and lectican C-type lectin domains: evidence for a crosslinking role for tenascins.
- 2004
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Ingår i: Structure. - : Elsevier BV. - 0969-2126. ; 12:8, s. 1495-1506
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Tidskriftsartikel (refereegranskat)abstract
- The C-terminal G3 domains of lecticans mediate crosslinking to diverse extracellular matrix (ECM) proteins during ECM assembly, through their C-type lectin (CLD) subdomains. The structure of the rat aggrecan CLD in a Ca(2+)-dependent complex with fibronectin type III repeats 3-5 of rat tenascin-R provides detailed support for such crosslinking. The CLD loops bind Ca2+ like other CLDs, but no carbohydrate binding is observed or possible. This is thus the first example of a direct Ca(2+)-dependent protein-protein interaction of a CLD. Surprisingly, tenascin-R does not coordinate the Ca2+ ions directly. Electron microscopy confirms that full-length tenascin-R and tenascin-C crosslink hyaluronan-aggrecan complexes. The results are significant for the binding of all lectican CLDs to tenascin-R and tenascin-C. Comparison of the protein interaction surface with that of P-selectin in complex with the PGSL-1 peptide suggests that direct protein-protein interactions of Ca(2+)-binding CLDs may be more widespread than previously appreciated.
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| 3. |
- Olin, Anders, et al.
(författare)
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The proteoglycans aggrecan and Versican form networks with fibulin-2 through their lectin domain binding
- 2001
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Ingår i: Journal of Biological Chemistry. - 1083-351X. ; 276:2, s. 1253-1261
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Tidskriftsartikel (refereegranskat)abstract
- Aggrecan, versican, neurocan, and brevican are important components of the extracellular matrix in various tissues. Their amino-terminal globular domains bind to hyaluronan, but the function of their carboxyl-terminal globular domains has long remained elusive. A picture is now emerging where the C-type lectin motif of this domain mediates binding to other extracellular matrix proteins. We here demonstrate that aggrecan, versican, and brevican lectin domains bind fibulin-2, whereas neurocan does not. As expected for a C-type lectin, the interactions are calcium-dependent, with K(D) values in the nanomolar range as measured by surface plasmon resonance. Solid phase competition assays with previously identified ligands demonstrated that fibulin-2 and tenascin-R bind the same site on the proteoglycan lectin domains. Fibulin-1 has affinity for the common site on versican but may bind to a different site on the aggrecan lectin domain. By using deletion mutants, the interaction sites for aggrecan and versican lectin domains were mapped to epidermal growth factor-like repeats in domain II of fibulin-2. Affinity chromatography and solid phase assays confirmed that also native full-length aggrecan and versican bind the lectin domain ligands. Electron microscopy confirmed the mapping and demonstrated that hyaluronan-aggrecan complexes can be cross-linked by the fibulins.
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| 4. |
- Stattin, Eva-Lena, et al.
(författare)
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A missense mutation in the aggrecan C-type lectin domain disrupts extracellular matrix interactions and causes dominant familial osteochondritis dissecans
- 2010
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Ingår i: American Journal of Human Genetics. - : Elsevier BV. - 0002-9297 .- 1537-6605. ; 86:2, s. 126-137
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Tidskriftsartikel (refereegranskat)abstract
- Osteochondritis dissecans is a disorder in which fragments of articular cartilage and subchondral bone dislodge from the joint surface. We analyzed a five-generation family in which affected members had autosomal-dominant familial osteochondritis dissecans. A genome-wide linkage analysis identified aggrecan (ACAN) as a prime candidate gene for the disorder. Sequence analysis of ACAN revealed heterozygosity for a missense mutation (c.6907G > A) in affected individuals, resulting in a p.V2303M amino acid substitution in the aggrecan G3 domain C-type lectin, which mediates interactions with other proteins in the cartilage extracellular matrix. Binding studies with recombinant mutated and wild-type G3 proteins showed loss of fibulin-1, fibulin-2, and tenascin-R interactions for the V2303M protein. Mass spectrometric analyses of aggrecan purified from patient cartilage verified that V2303M aggrecan is produced and present in the tissue. Our results provide a molecular mechanism for the etiology of familial osteochondritis dissecans and show the importance of the aggrecan C-type lectin interactions for cartilage function in vivo.
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| 7. |
- Aspberg, Anders, et al.
(författare)
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Cartilage proteoglycans
- 2016
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Ingår i: Cartilage: Volume 1: Physiology and Development. - Cham : Springer International Publishing. - 9783319295688 - 9783319295664 ; 1, s. 1-22
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Bokkapitel (refereegranskat)abstract
- Proteoglycans are key components of the cartilage extracellular matrix and essential for normal tissue function. The core protein and the glycosaminoglycan chains both contribute to function and provide different properties of the individual proteoglycans. This review is focused on the two main families of cartilage proteoglycans.The first of these is the lectican family, including aggrecan, versican, and the cartilage link protein. The aggregating proteoglycan network formed by aggrecan, link protein, and hyaluronan provides biomechanical properties that give the tissue its ability to withstand and distribute load.The second group discussed is the small leucine-rich repeat proteoglycan family, which includes decorin, biglycan, asporin, fibromodulin, lumican, keratocan, osteoadherin, proline-/arginine-rich end leucine-rich repeat protein, epiphycan, mimecan, opticin, chondroadherin, and chondroadherin-like. These proteoglycans bind collagens and are important regulators of cartilage extracellular matrix assembly. In addition, some of these proteoglycans bind and regulate growth factors and their receptors and regulate innate immunity through interactions with Toll-like receptors or the complement system.This review will give an overview of the structure and function of the different aggregating proteoglycans and small leucine-rich repeat proteoglycans in normal cartilage extracellular matrix.
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| 8. |
- Aspberg, Anders, et al.
(författare)
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Fibulin-1 is a ligand for the C-type lectin domains of aggrecan and versican
- 1999
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Ingår i: Journal of Biological Chemistry. - 1083-351X. ; 274:29, s. 20444-20449
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Tidskriftsartikel (refereegranskat)abstract
- The aggregating proteoglycans (aggrecan, versican, neurocan, and brevican) are important components of many extracellular matrices. Their N-terminal globular domain binds to hyaluronan, but the function of their C-terminal region containing a C-type lectin domain is less clear. We now report that a 90-kDa protein copurifies with recombinant lectin domains from aggrecan and versican, but not from the brain-specific neurocan and brevican. Amino acid sequencing of tryptic peptides from this protein identified it as fibulin-1. This extracellular matrix glycoprotein is strongly expressed in tissues where versican is expressed (blood vessels, skin, and developing heart), and also expressed in developing cartilage and bone. It is thus likely to interact with these proteoglycans in vivo. Surface plasmon resonance measurements confirmed that aggrecan and versican lectin domains bind fibulin-1, whereas brevican and neurocan do not. As expected for a C-type lectin, the interactions with fibulin-1 are Ca2+-dependent, with KD values in the low nanomolar range. Using various deletion mutants, the binding site for aggrecan and versican lectin domains was mapped to the epidermal growth factor-like repeats in domain II of fibulin-1. No difference in affinity was found for deglycosylated fibulin-1, indicating that the proteoglycan C-type lectin domains bind to the protein part of fibulin-1.
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