BACKGROUND Fetuin-A [also called alpha2-Heremans Schmid glycoprotein (AHSG)] is a circulating negative acute-phase glycoprotein synthesized and secreted by the liver and to a lesser extent the kidneys, placenta and the tongue. It has a high content of sugar moieties including sialic acid residues. Its molecular weight ranges from 51 to 67 kDa depending on the carbohydrate content. It is a member of the cystatin family of proteins even though it lacks cysteine protease inhibitory capacity.1 A number of studies suggest that fetuin-A is a multifunctional protein. A key physiological function attributed to the protein, determined with the aid of fetuin-A knockout mice, is its ability to inhibit ectopic Ca PO4 ion precipitation and vascular calcification. Moreover, it was demonstrated that fetuin-A is capable of binding to matrix metalloproteinases particularly MMP-9 and protects this enzyme from autolytic degradation. This interaction is most likely mediated by the cystatin domains in fetuin A, because other members of the family such as cystatin C also interact with matrix metalloproteinases. Interestingly, it has been shown that fetuin-A is also able to stabilize m-calpain, a cytoplasmic cysteine proteinase. Other studies demonstrated that fetuin-A mediates the activation of PI3 kinase/Akt. Furthermore, a critical functional role of this protein may depend on its rapid uptake by cells as well as its ability to act as an opsonin in the blood. In addition, Fetuin-A is accepted as a potent anti-inflammatory cytokine. It had been demonstrated that fetuin-A participates in macrophage deactivation, antifibrotic activity, and inhibition of apoptosis of vascular smooth muscle cells. Furthermore, it was reported that fetuin-A inhibits insulin receptor activation and autophosphorylation. Fetuin-A plays important role in insulin signaling and serum fetuin-A level an independent marker for insulin resistance.2 In addition, it was reported that fetuin-A is a major serum adhesive protein that mediates growth signaling in breast tumor cells. Fetuin-A is a major growth promoter in serum that can influence tumor establishment and growth.3
1. Nie, Z.: Am. J. Physiol. 263(3 Pt1):C551-62, 1992
2. Ishibashi, A. et al: J. Atheroscler. Thromb. 9:925-33, 2010
3. Sakwe, A.M. et al: J. Biol. Chem. 2010 (in press)
Products are for research use only. They are not intended for human, animal, or diagnostic applications.
Target Protein Species:
No detectable cross-reactivity
with any other cytokine.
Store at 4°C. Use within 6 months.
ELISA Kits are based on standard sandwich enzyme-linked immunosorbent assay technology. Freshly prepared standards, samples, and solutions are recommended for best results.