Annexin A1, ANXA1, also known as lipocortin I, is an anti-inflammatory protein originally identified as a phospholipase A2 (PLA2)-inhibitory protein. Its expression is induced by glucocorticoids in immune cells where it has been shown to promote cellular apoptosis. ANXA1 is a 40 kDa protein that binds to the cytosolic side of the cellular membrane in a Ca-dependent manner.
ANXA1 encodes a protein that belongs to a family of Ca(2+)-dependent phospholipid binding proteins which have a molecular weight of approximately 35,000 to 40,000 and are preferentially located on the cytosolic face of the plasma membrane. Annexin I protein has an apparent relative molecular mass of 40 kDa, with phospholipase A2 inhibitory activity. Since phospholipase A2 is required for the biosynthesis of the potent mediators of inflammation, prostaglandins and leukotrienes, annexin I may have potential anti-inflammatory activity.
