F11
Function
Factor XI triggers the middle phase of the intrinsic pathway of blood coagulation by activating factor IX.
Involvement in disease
Factor XI deficiency
FA11D
A hemorrhagic disease characterized by reduced levels and activity of factor XI resulting in moderate bleeding symptoms, usually occurring after trauma or surgery. Patients usually do not present spontaneous bleeding but women can present with menorrhagia. Hemorrhages are usually moderate.
None
The disease is caused by variants affecting the gene represented in this entry.
Post-translational modifications
N-glycosylated on both chains. N-glycosylated sites mainly consist of nonfucosylated sialylated biantennary (in high abundance) and/or triantennary (in low abundance) complex structures. Glycosylation at Asn-163 uses a rare non-canonical Asn-X-Cys glycosite.
Activated by factor XIIa (or XII), which cleaves each polypeptide after Arg-387 into the light chain, which contains the active site, and the heavy chain, which associates with high molecular weight (HMW) kininogen. Activated by F12 (activated); the presence of negatively charged surfaces accelerates activation (PubMed:2019570, PubMed:8427954). Activated by F2 (thrombin); the presence of negatively charged surfaces, such as polyphosphate and dextran sulfate, strongly accelerates activation (PubMed:2019570, PubMed:21976677). Autoactivated; the presence of negatively charged surfaces, such as polyphosphate and dextran sulfate, accelerates autoactivation and autolysis (PubMed:2019570, PubMed:21976677).
Sequence Similarities
Belongs to the peptidase S1 family. Plasma kallikrein subfamily.
Tissue Specificity
Isoform 2 is produced by platelets and megakaryocytes but absent from other blood cells.
Cellular localization
- Secreted
Alternative names
Coagulation factor XI, FXI, Plasma thromboplastin antecedent, PTA, F11