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The link proteins

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  • Proteoglycans
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Abstract

Aggregates of chondroitin-keratan sulfate proteoglycan (aggrecan) and hyaluronic acid (hyaluronan) are the major space-filling components of cartilage. A glycoprotein, link protein (LP; 40–48 kDa) stabilizes the aggregate by binding to both hyaluronic acid and aggrecan. In the absence of LP, aggregates are smaller (as estimated by rotary shadowing of electron micrographs) and less stable (they dissociate at pH 5) than they are in the presence of LP. The proteoglycan aggregate, including LP, is dissociated in the presence of chaotropes such as 4 M guanidine hydrochloride. On removal of the chaotrope, the complex will reassociate. This forms the basis of the isolation of LP from cartilage and has been described in detail elsewhere. Tryptic digestion of the proteoglycan aggregates results in a high molecular weight product that consists of hyaluronic acid to which is bound LP and the N-terminal globular domain of aggrecan (hyaluronic acid binding region; HABR) in a 1∶1 stoichiometry. The amino acid sequences of LP and HABR are surprisingly similar. The amino acid sequence can be divided into three domains; an N-terminal domain that falls into the immunoglobulin super-family and two C-terminal domains that are similar to each other. The DNA structure echoes this similarity, in that the major domains are reflected in three separate exons in both LP and HABR. The two C-terminal domains are largely responsible for the association with HA and are related to two recently described hyaluronate-binding proteins, CD44 and TSG-6. A variety of approaches, including analysis of the forms of LP found in vivo, rotary shadowing and analysis of the sequence in the immunoglobulin-like domain, have shed considerable light on the structure-function relationships of LP. This review describes the structure and function of LP in detail, focusing on what can be inferred from the similarity of LP, HABR and related molecules such as immunoglobulins and lymphocyte HA-receptors.

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References

  1. Aruffo, A., Stamenkovic, I., Melnick, M., Underhill, C. B., and Seed, B., CD44 is the principal cell surface receptor for hyaluronate. Cell61 (1990) 1303–1313.

    Article  CAS  PubMed  Google Scholar 

  2. Baker, J. R., and Neame, P. J., Isolation and characterization of the link proteins. Meth. Enzymol.144 (1987) 401–412.

    Article  CAS  Google Scholar 

  3. Barry, F. P., Gaw, J., Young, C. N., and Neame, P. J., Hyaluronan binding region of aggrecan from pig laryngeal cartilage. Amino acid sequence, analysis of the N-linked oligosaccharides and location of the keratan sulfate chain. Biochem. J.286 (1992) 761–769.

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  4. Bignami, A., Lane, W. S., Andrews, D., and Dahl, D., Structural similarity of hyaluronate binding proteins in brain and cartilage. Brain Res. Bull.22 (1989) 67–70.

    Article  CAS  PubMed  Google Scholar 

  5. Bonnet, F., Périn, J., and Jollès, P., Isolation and chemical characterization of two distinct “link proteins” from bovine nasal cartilage proteoglycan complex. Biochim. biophys. Acta532 (1978) 242–248.

    Article  CAS  PubMed  Google Scholar 

  6. Bonnet, F., Périn, J., Lorenzo, F., Jollès, J., and Jollès, P., An unexpected sequence homology between link proteins of the proteoglycan complex and immunoglobulin-like proteins. Biochim. biophys. Acta873 (1986) 152–155.

    Article  CAS  PubMed  Google Scholar 

  7. Bourne, Y., Rougé, P., and Cambillau, C., X-ray structure of a biantennary octasaccharide-lectin complex refined at 2.3-Å resolution. J. biol. Chem.267 (1992) 197–203.

    Article  CAS  PubMed  Google Scholar 

  8. Brown, T. A., Bouchard, T., St. John, T., Wayner, E., and Carter, W. G., Human keratinocytes express a new CD44 core protein (CD44E) as a heparan sulfate intrinsic membrane proteoglycan with additional exons. J. Cell Biol.113 (1991) 207–221.

    Article  CAS  PubMed  Google Scholar 

  9. Caterson, B., Baker, J. R., Christner, J. E., Lee, Y., and Lentz, M., Monoclonal antibodies as probes for determining the microheterogeneity of the link proteins of cartilage proteoglycans. J. biol. Chem.260 (1985) 11348–11356.

    Article  CAS  PubMed  Google Scholar 

  10. Chandrasekhar, S., Kleinman, H. K., and Hassell, J. R., Interaction of link protein with collagen. J. biol. Chem.258 (1983) 6226–6231.

    Article  CAS  PubMed  Google Scholar 

  11. Choi, H., Tang, L., Johnson, T., and Rosenberg, L., Proteoglycans from bovine nasal and articular cartilges. Fractionation of the link proteins by wheat germ agglutinin affinity chromatography. J. biol. Chem.260 (1985) 13370–13376.

    Article  CAS  PubMed  Google Scholar 

  12. Chothia, C., and Lesk, A. M., Canonical structures for the hypervariable regions of immunoglobulins. J. molec. Biol.196 (1987) 901–917.

    Article  CAS  PubMed  Google Scholar 

  13. Deák, F., Kiss, I., Sparks, K. J., Argraves, W. S., Hampikian, G., and Goetinck, P., Complete amino acid sequence of chicken cartilage link protein deduced from cDNA clones. Proc. natl Acad. Sci. USA83 (1986) 3766–3770.

    Article  PubMed  PubMed Central  Google Scholar 

  14. Doege, K., Hassell, J., Caterson, B., and Yamada, Y., Link protein cDNA sequence reveals a tandemly repeated protein structure. Proc. natl Acad. Sci. USA83 (1986) 3761–3765.

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  15. Doege, K., Sasaki, M., Horigan, E., Hassell, J. R., and Yamada, Y., Complete primary structure of the rat cartilage proteoglycan cone protein deduced from cDNA clones. J. biol. Chem.262 (1987) 17757–17767.

    Article  CAS  PubMed  Google Scholar 

  16. Doege, K., Sasaki, M., Kimura, T., and Yamada, Y., Complete coding sequence and deduced primary structure of the human cartilage large aggregating proteoglycan, Aggrecan. J. biol. Chem.266 (1991) 894–902.

    Article  CAS  PubMed  Google Scholar 

  17. Dudhia, J., and Hardingham, T. E., Isolation and sequence of cDNA clones for pig and human cartilage link protein. J. molec. Biol.206 (1989) 749–753.

    Article  CAS  Google Scholar 

  18. Flannery, C. R., Urbanek, P. J., and Sandy, J. D., The effect of maturation and aging on the structure and content of link proteins in rabbit articular cartilage. J. Orthop. Res.8 (1990) 78–85.

    Article  CAS  PubMed  Google Scholar 

  19. Fosang, A. J., and Hardingham, T. E., Isolation of the N-terminal globular protein domains from cartilage proteoglycans. Biochem. J.261 (1989) 801–809.

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  20. Gardell, S., Baker, J. R., Caterson, B., Heinegård, D., and Rodén, L., Link protein and a hyaluronic acid-binding region as components of aorta proteoglycan. Biochem. biophys. Res. Commun.95 (1980) 1823–1831.

    Article  CAS  PubMed  Google Scholar 

  21. Goetinck, P. F., Stirpe, N. S., Tsonis, P. A., and Carlone, D., The tandemly repeated sequences of cartilage link protein contain the sites for interaction with hyaluronic acid. J. Cell Biol.105 (1987) 2403–2408.

    Article  CAS  PubMed  Google Scholar 

  22. Goldstein, L. A., Zhou, D. F. H., Picker, L. J., Minty, C. N., Bargatze, R. F., Ding, J. F., and Butcher, E. C., A human lymphocyte homing receptor, the Hermes antigen, is related to cartilage proteoglycan core and link proteins. Cell56 (1989) 1063–1072.

    Article  CAS  PubMed  Google Scholar 

  23. Gregory, J. D., Multiple aggregation factors in cartilage proteoglycan. Biochem. J.133 (1973) 383–386.

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  24. Hardingham, T. E., The role of link-protein in the structure of cartilage proteoglycan aggregates. Biochem. J.177 (1979) 237–247.

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  25. Hardingham, T. E., and Muir, H., The specific interaction of hyaluronic acid with cartilage proteoglycans. Biochim. biophys. Acta279 (1972) 401–405.

    Article  CAS  PubMed  Google Scholar 

  26. Hardingham, T. E., Ewins, R. J., and Muir, H., Cartilage proteoglycans. Structure and heterogeneity of the protein core and the effects of specific protein modifications on the binding to hyaluronate. Biochem. J.157 (1976) 127–143.

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  27. Hardwick, C., Hoare, K., Owens, R., Hohn, H. P., Hook, M., Moore, D., Cripps, V., Austen, L., Nance, D. M., and Turley, E. A., Molecular cloning of a novel hyaluronan receptor that mediates tumor motility. J. Cell Biol.117 (1992) 1343–1350.

    Article  CAS  PubMed  Google Scholar 

  28. Hascall, V. C., and Sajdera, S. W., Proteinpolysaccharide complex from bovine nasal cartilage. The function of glycoprotein in the formation of aggregates. J. biol. Chem.244 (1969) 2384–2396.

    Article  CAS  PubMed  Google Scholar 

  29. Heinegård, D., and Hascall, V. C., Aggregation of cartilage proteoglycans: Characteristics of the proteins isolated from trypsin digests of aggregates. J. biol. Chem.249 (1974) 4250–4256.

    Article  PubMed  Google Scholar 

  30. Hering, T., and Sandell, L., Biosynthesis and cell-free translation of Swarm rat chondrosarcoma and bovine cartilage link proteins. J. biol. Chem.263 (1988) 1030–1036.

    Article  CAS  PubMed  Google Scholar 

  31. Hering, T., and Sandell, L., Biosynthesis and processing of bovine cartilage link proteins. J. biol. Chem.265 (1990) 2375–2382.

    Article  CAS  PubMed  Google Scholar 

  32. Hunkapiller, T., and Hood, L., Diversity of the immunoglobulin gene superfamily. Adv. Immun.44 (1989) 1–63.

    Article  CAS  PubMed  Google Scholar 

  33. Keiser, H., Schulman, H. J., and Sandson, J. I., Immunochemistry of cartilage proteoglycan. Immunodiffusion and gel-electrophoretic studies. Biochem. J.126 (1972) 163–169.

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  34. Kiss, I., Déak, F., Mestric, S., Delius, H., Sooss, J., Dekany, K., Argraves, W. S., Sparks, K. J., and Goetinck, P. F., Structure of the chicken link protein gene: exons correlate with the protein domains. Proc. natl Acad. Sci. USA84 (1987) 6399–6403.

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  35. LeBaron, R. G., Zimmermann, D. R., and Ruoslahti, E., Hyaluronate binding properties of versican. J. biol. Chem.267 (1992) 10003–10010.

    Article  CAS  PubMed  Google Scholar 

  36. Lee, T. H., Wisniewski, H. G., and Vilçek, J., A novel secretory tumor necrosis factor-inducible protein (TSG-6) is a member of the family of hyaluronate binding proteins, closely related to the adhesion receptor CD44. J. Cell Biol.116 (1992) 545–557.

    Article  CAS  PubMed  Google Scholar 

  37. Le Glédic, S., Périn, J., Bonnet, F., and Jollès, P., Interaction between the hyaluronic acid binding region and the common tryptic fragment of the link proteins from bovine nasal cartilage complex. An affinity chromatography study. Biochem. biophys. Res. Commun.104 (1982) 1298–1305.

    Article  PubMed  Google Scholar 

  38. Le Glédic, S., Périn, J., Bonnet, F., and Jollès, P., Identity of the protein cores of the two link proteins from bovine nasal cartilage proteoglycan complex. Localization of their sugar moieties. J. biol. Chem.258 (1983) 14759–14761.

    Article  PubMed  Google Scholar 

  39. Lesley, J., He, Q., Miyake, K., Hamann, A., Hyman, R., and Kincade, P. W., Requirements for hyaluronic acid binding by CD44: a role for the cytoplasmic domain and activation by antibody. J. exp. Med.175 (1992) 257–266.

    Article  CAS  PubMed  Google Scholar 

  40. Liu, J., Cassidy, J. D., Allan, A., Neame, P. J., Mort, J. S., Roughley, P. J., Link protein shows species variation in its susceptibility to proteolysis. J. orthop. Res.10 (1992) 621–630.

    Article  CAS  PubMed  Google Scholar 

  41. Lohmander, L. S., Fellini, S. A., Kimura, J. H., Stevens, R. L., and Hascall, V. C., Formation of proteoglycan aggregates in rat chondrosarcoma chondrocyte cultures treated with tunicamycin. J. biol. Chem.258 (1983) 12280–12286.

    Article  CAS  PubMed  Google Scholar 

  42. Lyon, M., Specific chemical modifications of link protein and their effect on binding to hyaluronate and cartilage proteoglycan. Biochim. biophys. Acta881 (1986) 22–29.

    Article  CAS  PubMed  Google Scholar 

  43. Lyon, M., and Nieduszynski, I. A., A study of equilibrium binding of link protein to hyaluronate. Biochem. J.213 (1983) 445–450.

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  44. Mörgelin, M., Engel, J., Heinegård, D., and Paulsson, M., Proteoglycans from the Swarm rat chondrosarcoma. Structure of the aggregates extracted with associative and dissociative solvents as revealed by electron microscopy. J. biol. Chem.267 (1992) 14275–14284.

    Article  PubMed  Google Scholar 

  45. Mörgelin, M., Paulsson, M., and Engel, J., Assembly of cartilage proteoglycan with hyaluronate and structure of the central filament in proteoglycan aggregate. Biochem. Soc. Trans.18 (1990) 204–207.

    Article  PubMed  Google Scholar 

  46. Mörgelin, M., Paulsson, M., Hardingham, T. E., Heinegärd, D., and Engel, J., Cartilage proteoglycans. Assembly with hyaluronate and link protein as studied by electron microscopy. Biochem. J.253 (1988) 175–185.

    Article  PubMed  PubMed Central  Google Scholar 

  47. Mort, J., Caterson, B., Poole, A., and Roughley, P., The origin of human cartilage proteoglycan link-protein heterogeneity and fragmentation during aging. Biochem. J.232 (1985) 805–812.

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  48. Mundlos, S., Meyer, R., Yamada, Y., and Zabel, B., Distribution of cartilage proteoglycan (aggrecan) core protein and link protein gene expression during human skeletal development. Matrix11 (1991) 339–346.

    Article  CAS  PubMed  Google Scholar 

  49. Neame, P., Christner, J., and Baker, J., The primary structure of link protein from rat chondrosarcoma proteoglycan aggregate. J. biol. Chem.261 (1986) 3519–3535.

    Article  CAS  PubMed  Google Scholar 

  50. Neame, P., Christner, J., and Baker, J., Cartilage proteoglycan aggregates. The link protein and proteoglycan amino-terminal globular domains have similar structures. J. biol. Chem.262 (1987) 17768–17778.

    Article  CAS  PubMed  Google Scholar 

  51. Neame, P., Périn, J., Bonnet, F., Christner, J., Jollès, P., and Baker, J., An amino acid sequence common to both cartilage proteoglycan and link protein. J. biol. Chem.260 (1985) 12402–12404.

    Article  CAS  PubMed  Google Scholar 

  52. Nguyen, Q., Liu, J., Roughley, P. J., and Mort, J. S., Link protein as a monitor in situ of endogeneous proteolysis in adult human articular cartilage. Biochem. J.278 (1991) 143–147.

    Article  PubMed  PubMed Central  Google Scholar 

  53. Nguyen, Q., Murphy, G., Roughley, P. J., and Mort, J. S., Degradation of proteoglycan aggregate by a cartilage metalloproteinase. Evidence for the involvement of stromelysin in the generation of link protein heterogeneity in situ. Biochem. J.259 (1989) 61–67.

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  54. Osborne-Lawrence, S. L., Sinclair, A. K., Hicks, R. C., Lacey, S. W., Eddy, R. L., Byers, M. G., Shows, T. B., and Duby, A. D., Complete amino acid sequence of human cartilage link protein deduced from cDNA clones and chromosomal assignment of the gene. Genomics8 (1990) 562–567.

    Article  CAS  PubMed  Google Scholar 

  55. Perides, G., Lane, W. S., Andrews, D., Dahl, D., and Bignami, A., Isolation and partial characterization of a glial hyaluronate-binding protein. J. biol. Chem.264 (1989) 5981–5987.

    Article  CAS  PubMed  Google Scholar 

  56. Périn, J., Bonnet, F., and Jollès, P., Structural relationship between link proteins and proteoglycan monomers. FEBS Lett.206 (1986) 73–77.

    Article  PubMed  Google Scholar 

  57. Périn, J., Bonnet, F., Jollès, J., and Jollès, P., Sequence data concerning the protein core of the cartilage proteoglycan monomers. Characterization of a sequence allowing the synthesis of an oligonucleotide probe. FEBS Lett.176 (1984) 37–42.

    Article  PubMed  Google Scholar 

  58. Périn, J., Bonnet, F., Pizon, V., Jollès, J., and Jollès, P., Structural data concerning the link proteins from bovine nasal cartilage proteoglycan complex. FEBS Lett.119 (1980) 333–336.

    Article  PubMed  Google Scholar 

  59. Périn, J., Bonnet, F., Thurieau, C., and Jollès, P., Link protein interactions with hyaluronate and proteoglycans. Characterization of two distinct domains in bovine cartilage link proteins. J. biol. Chem.262 (1987) 13269–13272.

    Article  PubMed  Google Scholar 

  60. Perkins, S. J., Nealis, A. S., Dudhia, J., Hardingham, T. E., Immunoglobulin fold and tandem repeat structures in proteoglycan N-terminal domains and link protein. J. molec. Biol.206 (1989) 737–748.

    Article  CAS  PubMed  Google Scholar 

  61. Perkins, S. J., Nealis, A. S., Dunham, D. G., Hardingham, T. E., and Muir, I. H., Molecular modeling of the multidomain structures of the proteoglycan binding region and the link protein of cartilage by neutron and synchrotron X-ray scattering. Biochemistry30 (1991) 10708–10716.

    Article  CAS  PubMed  Google Scholar 

  62. Perkins, S. J., Nealis, A. S., Dunham, D. G., Hardingham, T. E., and Muir, I. H., Neutron and X-ray solution-scattering studies of the ternary complex between proteoglycan-binding region, link protein and hyaluronan. Biochem. J.285 (1992) 263–268.

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  63. Poole, A. R., Reiner, A., Tang, L.-H., and Rosenberg, L. C., Proteoglycans from bovine nasal cartilage. Immunochemical studies of link protein. J. biol. Chem.255 (1980) 9295–9305.

    Article  CAS  PubMed  Google Scholar 

  64. Rhodes, C., Doege, K., Sasaki, M., and Yamada, Y., Alternative splicing generates two different mRNA species for rat link protein. J. biol. Chem.263 (1988) 6063–6067.

    Article  CAS  PubMed  Google Scholar 

  65. Ripellino, J. A., Margolis, R. U., and Margolis, R. K., Immunoelectron microscopic localization of hyaluronic acid-binding region and link protein epitopes in brain. J. Cell Biol.108 (1989) 1899–1907.

    Article  CAS  PubMed  Google Scholar 

  66. Roberts, C. R., Roughley, P. J., and Mort, J. S., Degradation of human proteoglycan aggregate induced by hydrogen peroxide. Protein fragmentation, amino acid modification and hyaluronic acid cleavage. Biochem. J.259 (1989) 805–811.

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  67. Rosenberg, L., Choi, L.-H., Tang, S., Johnson, T., Lyons, D. A., and Laue, T. M., Proteoglycans of bovine articular cartilage. The effects of divalent cations on the biochemical properties of link protein. J. biol. Chem.266 (1991) 7016–7024.

    Article  CAS  PubMed  Google Scholar 

  68. Rosenberg, L., Hellmann, W., and Kleinschmidt, A. K., Electron microscopic studies of proteoglycan aggregates from bovine articular cartilage. J. biol. Chem.250 (1975) 1877–1883.

    Article  CAS  PubMed  Google Scholar 

  69. Rosenberg, L., Tang, L. H., Pal, S., Johnson, T. L., and Choi, H. U., Proteoglycans of bovine articular cartilage. Studies of the direct interaction of link protein with hyaluronate in the absence of proteoglycan monomer. J. biol. Chem.263 (1988) 18071–18077.

    Article  CAS  PubMed  Google Scholar 

  70. Roughley, P. J., Poote, A. R., and Mort, J. S., The heterogeneity of link proteins isolated from human articular cartilage. J. biol. Chem.257 (1982) 11908–11914.

    Article  CAS  PubMed  Google Scholar 

  71. Sajdera, S. W., and Hascall, V. C., Proteinpolysaccharide complex from bovine nasal cartilage. A comparison of low and high shear extraction procedures. J. biol. Chem.244 (1969) 77–87.

    Article  CAS  PubMed  Google Scholar 

  72. Stirpe, N. S., and Goetinck, P. F., Gene regulation during cartilage differentiation: temporal and spatial expression of link protein and cartilage matrix protein in the developing limb. Development107 (1989) 23–33.

    Article  CAS  PubMed  Google Scholar 

  73. Stirpe, N. S., Dickerson, K. T., and Goetinck, P. F., The chicken embryonic mesonephros synthesizes link protein, and extracellular matrix molecule usually found in cartilage. Devl Biol.137 (1990) 419–424.

    Article  CAS  Google Scholar 

  74. Tsonis, P. A., and Goetinck, P. F., Expression of cartilage-matrix genes and localization of their translation products in the embryonic chick eye. Exp. Eye Res.46 (1988) 753–764.

    Article  CAS  PubMed  Google Scholar 

  75. Vijayagopal, P., Radhakrishnamurthy, B., Srinivasan, S. R., and Berenson, G. S., Isolation and characterization of a link protein from bovine aorta proteoglycan aggregate. Biochim. biophys. Acta839 (1985) 110–118.

    Article  CAS  PubMed  Google Scholar 

  76. Wolffe, E. J., Gause, W. C., Pelfrey, C. M., Holland, S. M., Steinberg, A. D., and August, T., The cDNA sequence of mouse Pgp-1 and homology to human CD44 cell surface antigen and proteoglycan core/link proteins. J. biol. Chem.265 (1990) 341–347.

    Article  CAS  PubMed  Google Scholar 

  77. Zimmermann, D. R., and Ruoslahti, E., Multiple domains of the large fibroblast proteoglycan, versican. EMBO J.8 (1989) 2975–2981.

    Article  CAS  PubMed  PubMed Central  Google Scholar 

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Neame, P.J., Barry, F.P. The link proteins. Experientia 49, 393–402 (1993). https://doi.org/10.1007/BF01923584

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