F12

This gene encodes coagulation factor XII which circulates in blood as a zymogen. This single chain zymogen is converted to a two-chain serine protease with an heavy chain (alpha-factor XIIa) and a light chain. The heavy chain contains two fibronectin-type domains, two epidermal growth factor (EGF)-like domains, a kringle domain and a proline-rich domain, whereas the light chain contains only a catalytic domain. On activation, further cleavages takes place in the heavy chain, resulting in the production of beta-factor XIIa light chain and the alpha-factor XIIa light chain becomes beta-factor XIIa heavy chain. Prekallikrein is cleaved by factor XII to form kallikrein, which then cleaves factor XII first to alpha-factor XIIa and then to beta-factor XIIa. The active factor XIIa participates in the initiation of blood coagulation, fibrinolysis, and the generation of bradykinin and angiotensin. It activates coagulation factors VII and XI. Defects in this gene do not cause any clinical symptoms and the sole effect is that whole-blood clotting time is prolonged. [provided by RefSeq, Jul 2008]

Full Name

Coagulation Factor XII

Research Area

Factor XII is a serum glycoprotein that participates in the initiation of blood coagulation, fibrinolysis, and the generation of bradykinin and angiotensin. Prekallikrein is cleaved by factor XII to form kallikrein, which then cleaves factor XII first to alpha-factor XIIa and then trypsin cleaves it to beta-factor XIIa. Alpha-factor XIIa activates factor XI to factor XIa.

Biological Process

Blood coagulation Source: GO_Central
Blood coagulation, intrinsic pathway Source: BHF-UCL
Factor XII activation Source: BHF-UCL
Fibrinolysis Source: UniProtKB-KW
Innate immune response Source: BHF-UCL
Plasma kallikrein-kinin cascade Source: BHF-UCL
Positive regulation of blood coagulation Source: BHF-UCL
Positive regulation of fibrinolysis Source: BHF-UCL
Positive regulation of plasminogen activation Source: BHF-UCL
Protein autoprocessing Source: BHF-UCL
Protein processing Source: BHF-UCL
Proteolysis Source: GO_Central
Response to misfolded protein Source: BHF-UCL
Zymogen activation Source: BHF-UCL

Cellular Location

Secreted

Involvement in disease

Factor XII deficiency (FA12D):
An asymptomatic anomaly of in vitro blood coagulation. Its diagnosis is based on finding a low plasma activity of the factor in coagulating assays. It is usually only accidentally discovered through pre-operative blood tests. Factor XII deficiency is divided into two categories, a cross-reacting material (CRM)-negative group (negative F12 antigen detection) and a CRM-positive group (positive F12 antigen detection).
Hereditary angioedema 3 (HAE3):
A hereditary angioedema occurring only in women. Hereditary angioedema is an autosomal dominant disorder characterized by episodic local swelling involving subcutaneous or submucous tissue of the upper respiratory and gastrointestinal tracts, face, extremities, and genitalia. Hereditary angioedema type 3 differs from types 1 and 2 in that both concentration and function of C1 esterase inhibitor are normal. Hereditary angioedema type 3 is precipitated or worsened by high estrogen levels (e.g., during pregnancy or treatment with oral contraceptives).

PTM

Factor XII is activated by kallikrein in alpha-factor XIIa, which is further converted by trypsin into beta-factor XIIa. Alpha-factor XIIa is composed of an NH2-terminal heavy chain, called coagulation factor XIIa heavy chain, and a COOH-terminal light chain, called coagulation factor XIIa light chain, connected by a disulfide bond. Beta-factor XIIa is composed of 2 chains linked by a disulfide bond, an N-terminal nonapeptide, called beta-factor XIIa part 1, and coagulation factor XIIa light chain, also known in this context as beta-factor XIIa part 2.
O- and N-glycosylated. The O-linked polysaccharides were not identified, but are probably the mucin type linked to GalNAc.