Osteonectin is a glycoprotein in the bone that binds calcium. It is secreted by osteoblasts during bone formation, initiating mineralization and promoting mineral crystal formation. Osteonectin also shows affinity for collagen in addition to bone mineral calcium. Some current research shows a correlation between osteonectin over expression and ampullary cancers and chronic pancreatitis.
Osteonectin is an acidic, secreted extracellular matrix glycoprotein that plays a vital role in bone mineralization, cell-matrix interactions, and collagen binding. Osteonectin also increases the production and activity of matrix metalloproteinases, a function important to invading cancer cells within bone. Additional functions of osteonectin beneficial to tumor cells include angiogenesis, proliferation and migration. Overexpression of osteonectin is reported in many human cancers such as breast, prostate and colon.[1]
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References
Further reading
- Yan Q, Sage EH (1999). "SPARC, a matricellular glycoprotein with important biological functions.". J. Histochem. Cytochem. 47 (12): 1495–506. PMID 10567433.
- Altura BM (1975). "Pharmacological effects of alpha-methyldopa, alpha-methylnorepinephrine, and octopamine on rat arteriolar, arterial, and terminal vascular smooth.". Circ. Res. 36 (6 Suppl 1): 233–40. PMID 1093755.
- Raines EW, Lane TF, Iruela-Arispe ML, et al. (1992). "The extracellular glycoprotein SPARC interacts with platelet-derived growth factor (PDGF)-AB and -BB and inhibits the binding of PDGF to its receptors.". Proc. Natl. Acad. Sci. U.S.A. 89 (4): 1281–5. PMID 1311092.
- Mundlos S, Schwahn B, Reichert T, Zabel B (1992). "Distribution of osteonectin mRNA and protein during human embryonic and fetal development.". J. Histochem. Cytochem. 40 (2): 283–91. PMID 1552170.
- Kelm RJ, Mann KG (1990). "Human platelet osteonectin: release, surface expression, and partial characterization.". Blood 75 (5): 1105–13. PMID 2306517.
- Young MF, Day AA, Dominquez P, et al. (1990). "Structure and expression of osteonectin mRNA in human tissue.". Connect. Tissue Res. 24 (1): 17–28. PMID 2338025.
- Metsäranta M, Young MF, Sandberg M, et al. (1989). "Localization of osteonectin expression in human fetal skeletal tissues by in situ hybridization.". Calcif. Tissue Int. 45 (3): 146–52. PMID 2505905.
- Sage H, Vernon RB, Funk SE, et al. (1989). "SPARC, a secreted protein associated with cellular proliferation, inhibits cell spreading in vitro and exhibits Ca+2-dependent binding to the extracellular matrix.". J. Cell Biol. 109 (1): 341–56. PMID 2745554.
- Villarreal XC, Mann KG, Long GL (1989). "Structure of human osteonectin based upon analysis of cDNA and genomic sequences.". Biochemistry 28 (15): 6483–91. PMID 2790009.
- Swaroop A, Hogan BL, Francke U (1988). "Molecular analysis of the cDNA for human SPARC/osteonectin/BM-40: sequence, expression, and localization of the gene to chromosome 5q31-q33.". Genomics 2 (1): 37–47. PMID 2838412.
- Wewer UM, Albrechtsen R, Fisher LW, et al. (1988). "Osteonectin/SPARC/BM-40 in human decidua and carcinoma, tissues characterized by de novo formation of basement membrane.". Am. J. Pathol. 132 (2): 345–55. PMID 3400777.
- Clezardin P, Malaval L, Ehrensperger AS, et al. (1988). "Complex formation of human thrombospondin with osteonectin.". Eur. J. Biochem. 175 (2): 275–84. PMID 3402455.
- Lankat-Buttgereit B, Mann K, Deutzmann R, et al. (1988). "Cloning and complete amino acid sequences of human and murine basement membrane protein BM-40 (SPARC, osteonectin).". FEBS Lett. 236 (2): 352–6. PMID 3410046.
- Stenner DD, Tracy RP, Riggs BL, Mann KG (1986). "Human platelets contain and secrete osteonectin, a major protein of mineralized bone.". Proc. Natl. Acad. Sci. U.S.A. 83 (18): 6892–6. PMID 3489235.
- Jundt G, Berghäuser KH, Termine JD, Schulz A (1987). "Osteonectin--a differentiation marker of bone cells.". Cell Tissue Res. 248 (2): 409–15. PMID 3581152.
- Fisher LW, Hawkins GR, Tuross N, Termine JD (1987). "Purification and partial characterization of small proteoglycans I and II, bone sialoproteins I and II, and osteonectin from the mineral compartment of developing human bone.". J. Biol. Chem. 262 (20): 9702–8. PMID 3597437.
- Sage H, Johnson C, Bornstein P (1984). "Characterization of a novel serum albumin-binding glycoprotein secreted by endothelial cells in culture.". J. Biol. Chem. 259 (6): 3993–4007. PMID 6368555.
- Termine JD, Kleinman HK, Whitson SW, et al. (1982). "Osteonectin, a bone-specific protein linking mineral to collagen.". Cell 26 (1 Pt 1): 99–105. PMID 7034958.
- Xie RL, Long GL (1995). "Role of N-linked glycosylation in human osteonectin. Effect of carbohydrate removal by N-glycanase and site-directed mutagenesis on structure and binding of type V collagen.". J. Biol. Chem. 270 (39): 23212–7. PMID 7559469.
- Maurer P, Hohenadl C, Hohenester E, et al. (1995). "The C-terminal portion of BM-40 (SPARC/osteonectin) is an autonomously folding and crystallisable domain that binds calcium and collagen IV.". J. Mol. Biol. 253 (2): 347–57. doi:10.1006/jmbi.1995.0557. PMID 7563094.
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1bmo: BM-40, FS/EC DOMAIN PAIR
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1nub: HELIX C DELETION MUTANT OF BM-40 FS-EC DOMAIN PAIR
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1sra: STRUCTURE OF A NOVEL EXTRACELLULAR CA2+-BINDING MODULE IN BM-40(SLASH)SPARC(SLASH)OSTEONECTIN
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