Proteoglycans: Their structure, interactions and molecular organization in cartilage

Hardingham, Timothy E.

doi:10.1042/bst0090489

Cited by 125 publications

(67 citation statements)

References 11 publications

(13 reference statements)

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“…A typical feature of hyaline cartilage is the formation of high molecular weight proteoglycan aggregates (31). These were observed in primary monolayer cultures (Figure 2) and in first passage on freshly isolated, "native" chondrocytes and cultured chondrocytes (CC), and these were compared with cultured fibroblasts (CF) of foreskin or synovial tissue origin.…”

Section: Resultsmentioning

confidence: 99%

Changes in cell surface antigen expression on human articular chondrocytes induced by gamma‐interferon

Jahn

Burmester

Schmid

et al. 1987

Arthritis & Rheumatism

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Ia antigens (class I1 HLA molecules) have been detected on cells eluted from affected human cartilage in certain disease states, but not on normal cartilage cells. Because the presence of Ia antigens on chondrocytes may play an important role in rheumatic diseases, we investigated the induction of these molecules by yinterferon ( y-IFN), a potent Ia-inducing lymphokine. Human articular chondrocytes were incubated with recombinant y-IFN, and the expression of Ia antigens was studied by cell sorter analysis, using a panel of reagents that detect monomorphic and polymorphic specificities of the DR and DQ Ia antigen families. While the induction of DR antigens, including polymorphic DR specificities, was readily obtained with y-IFN (50-95% positive cells), DQ antigens were negative or were displayed only on a lower percentage of chondrocytes (5-600/0). In addition, incubation with y-IFN led to an increased expression of HLA class I antigens. The expression of various other surface markers either remained unchanged (as in 4F2 and BA-2) or showed

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Section: Resultsmentioning

confidence: 99%

Changes in cell surface antigen expression on human articular chondrocytes induced by gamma‐interferon

Jahn

Burmester

Schmid

et al. 1987

Arthritis & Rheumatism

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“…Therefore, it seems likely that HA 10 is the minimum length of HA able to occupy the HA-binding site on G1, but that HA 12 has slightly tighter binding. Earlier estimates of the footprint of aggrecan on HA suggested that at maximal packing density it occupied a longer stretch of HA (ϳHA 18 ) than was part of the minimal binding site (31) and more recent experiments comparing the binding of recombinant G1 to HA 32 and HA 40 also suggested a longer site occupied, which may result from negative cooperativity (13). Alternatively, this may be caused by the spatial constraints of how close G1 domains (which each have 2 Link modules and an Ig fold) can pack when bound to HA.…”

Section: Effect Of Ph On the Binding Of The G1 Domain Of Aggrecan Withmentioning

confidence: 99%

Hyaluronan Binding to Link Module of TSG-6 and to G1 Domain of Aggrecan Is Differently Regulated by pH

Heng

Gribbon

Day

et al. 2008

Journal of Biological Chemistry

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The physiological functions of hyaluronan (HA) in the extracellular matrix of vertebrate tissues involve a range of specific protein interactions. In this study, the interaction of HA with the Link module from TSG-6 (Link_TSG6) and G1 domain of aggrecan (G1), were investigated by a biophysical analysis of translational diffusion in dilute solution using confocal fluorescence recovery after photobleaching (confocal FRAP). Both Link_TSG6 and G1 were shown to bind to polymeric HA and these interactions could be competed with HA 8 and HA 10 oligosaccharides, respectively. Equilibrium experiments showed that the binding affinity of Link_TSG6 to HA was maximal at pH 6.0, and reduced dramatically above and below this pH. In contrast, G1 had maximum binding at pH 7.0 -8.0 and moderate to strong binding affinity over a much broader pH range (5.5-8.0). The K D determined for Link_TSG6 binding to HA showed a 100-fold increase in binding affinity between pH 7.4 and 6.0, whereas G1 showed a 75-fold decrease in binding affinity over the same pH range. The sharp difference observed in their pH binding suggests that pH controls the physiological function of TSG-6, with a low affinity for HA at neutral pH, but with increased affinity as the pH falls below pH 7. TSG-6 and aggrecan interact with HA through structurally homologous domains and the difference in pH-dependent binding can be understood in terms of differences in the presence and topographical distribution of key regulatory amino acids in Link_TSG6 and in the related tandem Link domains in aggrecan G1.

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“…In these aggregates proteoglycan monomers interact with link protein and each of these molecules interacts with hyaluronic acid (1). As many as 100 proteoglycan monomers and link proteins can interact with a single hyaluronic acid polymer (2). The domains within link protein that allow for these characteristic molecular associations can begin to be identified from the analysis of the amino acid sequence and its gene structure.…”

mentioning

confidence: 99%

Structure of the chicken link protein gene: exons correlate with the protein domains.

Kiss¹,

Deák²,

Mestric³

et al. 1987

Proc. Natl. Acad. Sci. U.S.A.

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The structure of the chicken link protein gene has been determined from a series of genomic clones that cover the entire coding region as well as the complete 3'-untranslated region and a small portion of the 5'-untranslated region. The gene is >80 kilobase pairs long and is present in a single copy in the chicken genome. The link protein gene contains at least five exons with four encoding the entire protein. We have reported (3) the isolation of cDNA clones encoding the entire chicken cartilage link protein (LP) and deduced the amino acid sequence from the nucleotide sequence. A comparison between the complete amino acid sequence of rat LP (4) and chicken LP (3) shows a very high degree of homology. The analysis of the amino acid sequence of LPs reveals that the protein can be divided into several domains. The N-terminal half of LP has homology with the repeating units of the human free secretory component, the 'y chain of the T-cell receptor, and three types of immunoglobulin variable regions (5). The C-terminal half contains tandemly repeated sequences that may be the hyaluronic acid binding regions of LP (3,4,6).Here we report on the isolation of chicken LP genomic clones covering the entire protein coding region as well as the complete 3'-untranslated region of the mRNA. The structure of the gene is compared to the domain structure of the protein. MATERIALS AND METHODSConstruction and Screening of the Chicken Genomic Library. High molecular weight DNA, isolated from 9-day chicken embryos, was partially digested with Sau3AI and inserted into the BamHI site of XEMBL3 vector DNA as described by Frischauf et al. (7). Ligation mixtures were packaged in vitro, and 0.5-1 x 106 recombinant phages were amplified in Q359 host cells.The library was screened according to the method of Benton and Davis (8) using '2P-labeled LP cDNA probes (3). Duplicate filters were hybridized as described by Maniatis et al. (9). Phage DNA was isolated (10), and restriction maps were established based on the results of single and double digests of phage DNA. Restriction fragments were subcloned in pUC8/pUC9 (11) or in M13mp8/Ml3mp9 (12). These genomic fragments as well as different LP cDNA fragments were used as probes in Southern hybridizations (13) to confirm the restriction map.DNA fragments were labeled with 32P by random oligonucleotide priming (14). Hybridization and washing conditions of Southern blots of restriction digests of genomic DNA were carried out according to Jeffreys and Flavell (15).Electron Microscopy. Separated complementary DNA strands of genomic clones were isolated from agarose gels as described (16). Double heteroduplexes were prepared by incubating the complementary DNA strands of appropriate phages with 3-5 ,ug of chicken sternal total RNA in 80% (vol/vol) formamide and 0.1 M Hepes (pH 8.3), 0.4 M NaCl, 0.01 M EDTA (17) in a final volume of 25 ,ul at a DNA concentration of 5 uzg/ml. Incubation was done for 15 hr at 45°C. Excess RNA was removed by chromatography on a Sephacryl S-1000 column (2 x 45 mm...

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Proteoglycans: Their structure, interactions and molecular organization in cartilage

Cited by 125 publications

References 11 publications

Changes in cell surface antigen expression on human articular chondrocytes induced by gamma‐interferon

Changes in cell surface antigen expression on human articular chondrocytes induced by gamma‐interferon

Hyaluronan Binding to Link Module of TSG-6 and to G1 Domain of Aggrecan Is Differently Regulated by pH

Structure of the chicken link protein gene: exons correlate with the protein domains.

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