- Fetuin
Fetuins are
blood proteins , which are made in theliver and secreted into theblood stream . They belong to a large group of bindingprotein s mediating the transport and availability of a wide variety of cargo substances in the blood stream. The best known representative of these carrier proteins isserum albumin , the most abundant protein in theblood plasma of adultanimal s. Fetuin is more abundant in fetal blood, hence the name fetuin (from lat. fetus). Fetal calf serum contains more fetuin than albumin, while adult serum contains more albumin than fetuin.Human fetuin is synonymous with α2-HS-Glycoprotein (genetic symbol AHSG), α2-HS, A2HS, AHS, HSGA and fetuin-A. Fetuin-A exists as a single copy gene in the human and mouse genomes. A closely related gene, fetuin-B also exists in the human,rat andmouse genome s. Like fetuin-A fetuin-B is made predominantly by the liver and to a lesser extent by a number of secretory tissues. Fetuins exist it in all vertebrate genomes includingfish andreptile s. Fetuins are members of a family of proteins, which evolved from the protein cystatin bygene duplication and exchange of gene segments. Thus fetuins belong to the cystatin superfamily of proteins. Fetuin relatives within this superfamiliy are thehistidine -rich glycoprotein (HRG) and kininogen (KNG).The function of Fetuin-A in the body was determined by gene knockout technology in mice. Knocking out the gene for fetuin-A rendered the mice completely fetuin-A deficient. Feeding a
mineral -rich diet to fetuin-A deficient mice resulted in widespread calcification, »ectopic mineralization« oflung ,heart andkidney s in these mice. The calcification became drastically exacerbated, when the fetuin-A knockout was combined with the genetic background DBA/2. The mouse strain DBA/2 is known for its proneness to calcify damaged tissues – a process called dystrophic calcification. Fetuin-A deficiency dramatically increased the calcification proneness of these mice in that all mice sponteneously calcified throughout their body even without mineral-rich diet or surgical tissue trauma. Therefore Fetuin A is regarded as a potent inhibitor of systemic calcification.External links
* Demetriou M, Binkert C, Sukhu B, Tenenbaum HC, Dennis JW. Fetuin/alpha2-HS glycoprotein is a transforming growth factor-beta type II receptor mimic and cytokine antagonist. [http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Retrieve&list_uids=8662721&dopt=Abstract Fetuin/alpha2-HS glycoprotein] "Pubmed"
* Mineral Chaperones. [http://www.ncbi.nlm.nih.gov/pubmed/18080808] "Pubmed"
* The serum protein alpha 2-Heremans-Schmid glycoprotein/fetuin-A is a systemically acting inhibitor of ectopic calcification. [http://www.ncbi.nlm.nih.gov/pubmed/12897203] "Pubmed"
* Association of low fetuin-A (AHSG) concentrations in serum with cardiovascular mortality in patients on dialysis: a cross-sectional study. [http://www.ncbi.nlm.nih.gov/pubmed/12642050] "Pubmed"
* Structural basis of calcification inhibition by alpha 2-HS glycoprotein/fetuin-A. Formation of colloidal calciprotein particles. [http://www.ncbi.nlm.nih.gov/pubmed/12556469] "Pubmed"
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