Matrix gla protein
Encyclopedia
Matrix gla protein is a protein
found in numerous body tissues that requires vitamin K
for its optimum function. It is present in bone
(together with the related vitamin K-dependent protein osteocalcin
), as well as in heart
, kidney
and lung
. In bone, its production is increased by vitamin D
.
in 1990.
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
.
, 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.
Protein
Proteins are biochemical compounds consisting of one or more polypeptides typically folded into a globular or fibrous form, facilitating a biological function. A polypeptide is a single linear polymer chain of amino acids bonded together by peptide bonds between the carboxyl and amino groups of...
found in numerous body tissues that requires vitamin K
Vitamin K
Vitamin K is a group of structurally similar, fat soluble vitamins that are needed for the posttranslational modification of certain proteins required for blood coagulation and in metabolic pathways in bone and other tissue. They are 2-methyl-1,4-naphthoquinone derivatives...
for its optimum function. It is present in bone
Bone
Bones are rigid organs that constitute part of the endoskeleton of vertebrates. They support, and protect the various organs of the body, produce red and white blood cells and store minerals. Bone tissue is a type of dense connective tissue...
(together with the related vitamin K-dependent protein osteocalcin
Osteocalcin
Osteocalcin, also known as bone gamma-carboxyglutamic acid-containing protein , is a noncollagenous protein found in bone and dentin. In humans, the osteocalcin is encoded by the BGLAP gene.- Function :...
), as well as in heart
Heart
The heart is a myogenic muscular organ found in all animals with a circulatory system , that is responsible for pumping blood throughout the blood vessels by repeated, rhythmic contractions...
, kidney
Kidney
The kidneys, organs with several functions, serve essential regulatory roles in most animals, including vertebrates and some invertebrates. They are essential in the urinary system and also serve homeostatic functions such as the regulation of electrolytes, maintenance of acid–base balance, and...
and lung
Lung
The lung is the essential respiration organ in many air-breathing animals, including most tetrapods, a few fish and a few snails. In mammals and the more complex life forms, the two lungs are located near the backbone on either side of the heart...
. In bone, its production is increased by vitamin D
Vitamin D
Vitamin D is a group of fat-soluble secosteroids. In humans, vitamin D is unique both because it functions as a prohormone and because the body can synthesize it when sun exposure is adequate ....
.
Genetics
The MGP was linked to the short arm of chromosome 12Chromosome 12 (human)
Chromosome 12 is one of the 23 pairs of chromosomes in humans. People normally have two copies of this chromosome. Chromosome 12 spans about 143 million base pairs and represents between 4 and 4.5 percent of the total DNA in cells.Identifying genes on each chromosome is an active area of genetic...
in 1990.
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 carboxylatedCarboxylation
Carboxylation in chemistry is a chemical reaction in which a carboxylic acid group is introduced in a substrate. The opposite reaction is decarboxylation.-Carboxylation in organic chemistry:In organic chemistry many different protocols exist for carboxylation...
by the enzyme gamma-glutamyl carboxylase
Gamma-glutamyl carboxylase
Gamma-glutamyl carboxylase is an enzyme that in humans is encoded by the GGCX gene, located on chromosome 2 at 2p12.-Function:Gamma-glutamyl carboxylase is an enzyme that catalyzes the posttranslational modification of vitamin K-dependent proteins...
in a reaction that requires Vitamin K hydroquinone
Vitamin K
Vitamin K is a group of structurally similar, fat soluble vitamins that are needed for the posttranslational modification of certain proteins required for blood coagulation and in metabolic pathways in bone and other tissue. They are 2-methyl-1,4-naphthoquinone derivatives...
. This process also occurs with a number of proteins involved in coagulation
Coagulation
Coagulation is a complex process by which blood forms clots. It is an important part of hemostasis, the cessation of blood loss from a damaged vessel, wherein a damaged blood vessel wall is covered by a platelet and fibrin-containing clot to stop bleeding and begin repair of the damaged vessel...
: prothrombin, factor VII
Factor VII
Factor VII is one of the proteins that causes blood to clot in the coagulation cascade. It is an enzyme of the serine protease class. A recombinant form of human factor VIIa has U.S. Food and Drug Administration approval for uncontrolled bleeding in hemophilia patients...
, factor IX
Factor IX
Factor IX is one of the serine proteases of the coagulation system; it belongs to peptidase family S1. Deficiency of this protein causes hemophilia B. It was discovered in 1952 after a young boy named Stephen Christmas was found to be lacking this exact factor, leading to...
and factor X
Factor X
Factor X, also known by the eponym Stuart-Prower factor or as prothrombinase, is an enzyme of the coagulation cascade. It is a serine endopeptidase .-Physiology:...
, protein C
Protein C
Protein C, also known as autoprothrombin IIA and blood coagulation factor XIV, is a zymogenic protein, the activated form of which plays an important role in regulating blood clotting, inflammation, cell death and maintaining the permeability of blood vessel walls in humans and other animals...
, protein S
Protein S
Protein S is a vitamin K-dependent plasma glycoprotein synthesized in the endothelium. In the circulation, Protein S exists in two forms: a free form and a complex form bound to complement protein C4b. In humans, protein S is encoded by the PROS1 gene...
and protein Z
Protein Z
Protein Z also known as PROZ is a protein which in humans is encoded by the PROZ gene.Protein Z is a member of the coagulation cascade, the group of blood proteins that leads to the formation of blood clots. It is vitamin K-dependent, and its functionality is therefore impaired in warfarin therapy...
.
Role in disease
Abnormalities in the MGP gene have been linked with Keutel syndromeKeutel syndrome
Keutel syndrome is a rare autosomal recessive genetic disorder characterized by abnormal diffuse cartilage calcification, hypoplasia of the mid-face, peripheral pulmonary stenosis, hearing loss, short distal phalanges of the fingers and mild mental retardation.It was first identified in 1972.It is...
, a rare condition characterised by abnormal calcium deposition in cartilage
Cartilage
Cartilage is a flexible connective tissue found in many areas in the bodies of humans and other animals, including the joints between bones, the rib cage, the ear, the nose, the elbow, the knee, the ankle, the bronchial tubes and the intervertebral discs...
, peripheral stenosis of the pulmonary artery
Pulmonary artery
The pulmonary arteries carry deoxygenated blood from the heart to the lungs. They are the only arteries that carry deoxygenated blood....
, 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.