ANXA5
Description
The ANXA5 (annexin A5) is a protein-coding gene located on chromosome 4.
Annexin A5 (or annexin V) is a cellular protein in the annexin group. It is commonly used in flow cytometry to detect apoptotic cells due to its ability to bind to phosphatidylserine, a marker of apoptosis when found on the outer leaflet of the plasma membrane. The exact function of annexin A5 remains unclear, but it has been proposed to play a role in inhibiting blood coagulation by competing with prothrombin for phosphatidylserine binding sites. Additionally, it is suggested to inhibit the activity of phospholipase A1. These properties have been observed in in vitro experiments.
Antibodies against annexin A5 are present in patients with antiphospholipid syndrome (APS), a thrombophilic disease characterized by autoantibodies against phospholipid compounds. Annexin A5 creates a shield around negatively charged phospholipid molecules, preventing their involvement in coagulation reactions. In APS, the formation of this shield is disrupted by antibodies, leading to an increase in phospholipid molecules on cell membranes, accelerating coagulation reactions and resulting in the blood-clotting characteristic of the syndrome.
Upregulation of annexin A5 has been observed in papillary thyroid carcinoma.
Annexin A5 functions as an anticoagulant protein by indirectly inhibiting the thromboplastin-specific complex, a crucial component of the blood coagulation cascade.
ANXA5 is also known as ANX5, CPB-I, ENX2, HEL-S-7, PP4, RPRGL3, VAC-alph.
