Matrix gla protein

Matrix gla protein (MGP) is member of a family of vitamin-K 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.

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

It is present in bone together with the related vitamin K-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. Its mRNA sequence length is 585 bases long in humans.

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.

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

External links

• matrix Gla protein at the US National Library of Medicine Medical Subject Headings (MeSH)