Biology:Matrix gla protein

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A representation of the 3D structure of the protein myoglobin showing turquoise α-helices.
Generic protein structure example

Matrix gla protein (MGP) is member of a family of vitamin-K2 dependent, Gla-containing proteins. MGP has a high affinity binding to calcium ions, similar to other Gla-containing proteins. The protein acts as an inhibitor of vascular mineralization and plays a role in bone organization.[1][2]

MGP is found in a number of body tissues in mammals, birds, and fish. Its mRNA is present in bone, cartilage, heart, and kidney.[3]

It is present in bone together with the related vitamin K2-dependent protein osteocalcin. In bone, its production is increased by vitamin D.

Genetics

The MGP was linked to the short arm of chromosome 12 in 1990.[4] Its mRNA sequence length is 585 bases long in humans.[5]

Physiology

MGP and osteocalcin are both calcium-binding proteins that may participate in the organisation of bone tissue. Both have glutamate residues that are post-translationally carboxylated by the enzyme gamma-glutamyl carboxylase in a reaction that requires Vitamin K hydroquinone.

This process also occurs with a number of proteins involved in coagulation: prothrombin, factor VII, factor IX and factor X, protein C, protein S and protein Z.

Role in disease

Abnormalities in the MGP gene have been linked with Keutel syndrome, a rare condition characterised by abnormal calcium deposition in cartilage, peripheral stenosis of the pulmonary artery, and midfacial hypoplasia.[6]

Mice that lack MGP develop to term but die within two months as a result of arterial calcification which leads to blood-vessel rupture.[2]

References

  1. "A role for the endothelium in vascular calcification". Circ. Res. 113 (5): 495–504. 2013. doi:10.1161/CIRCRESAHA.113.301792. PMID 23852538. 
  2. 2.0 2.1 "Spontaneous calcification of arteries and cartilage in mice lacking matrix GLA protein". Nature 386 (6620): 78–81. March 1997. doi:10.1038/386078a0. PMID 9052783. 
  3. "Matrix Gla protein gene expression and protein accumulation colocalize with cartilage distribution during development of the teleost fish Sparus aurata". Bone 32 (3): 201–10. 2003. doi:10.1016/S8756-3282(02)00981-X. PMID 12667547. 
  4. "Molecular structure, chromosome assignment, and promoter organization of the human matrix Gla protein gene". J. Biol. Chem. 265 (25): 15040–8. 1990. PMID 2394711. http://www.jbc.org/cgi/reprint/265/25/15040. 
  5. "Sequence: M58549.1 : Human matrix Gla protein (MGP) mRNA, complete cds.". European Nucleotide Archive. European Bioinformatics Institute. http://www.ebi.ac.uk/ena/data/view/M58549. 
  6. "Mutations in the gene encoding the human matrix Gla protein cause Keutel syndrome". Nat. Genet. 21 (1): 142–4. 1999. doi:10.1038/5102. PMID 9916809. 

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