Annexin A2 (D11G2) Rabbit mAb #8235

Annexin A2 (ANXA2), also known as lipocortin II or calpactin-1 heavy chain, is a 36 kDa member of the annexin superfamily that binds phospholipids and other proteins in a calcium-dependent manner via annexin repeats (1). Annexin A2 contains four such repeats through which it mediates protein-protein and protein-lipid interactions (1-4). It forms a constitutive heterotetramer with S100A10, acting as a bridge between the actin cytoskeleton, plasma membrane, and endocytotic vesicle machinery (5-7). Originally identified as a protein inhibitor of phospholipase A2, annexin A2 has subsequently been shown to interact with an array of protein and non-protein partners, including F-actin, spectrin, SNARE complexes, RNA, and virus particles (4,6,8,9). Annexin A2 has also been shown to have receptor-like activity and is detected on the surface of macrophages and vascular endothelial cells where it mediates macrophage activation and Factor Xa signaling, respectively (10-13). Upregulation of annexin A2 at the cell surface is thought to be modulated by phosphorylation at Tyr23 by Src (14-18). Interestingly, phosphorylation at Tyr23 has recently been shown to be required for cell surface expression of annexin A2 where it mediates motility, invasiveness, and overall metastatic potential of certain pancreatic cancer cells (19,20). Annexin A2 has also been shown to be heavily phosphorylated on serine residues in response to PKC activation via a pleiotropic mechanism (21-23). For a complete list of curated phosphorylation sites on annexin A2, please see PhosphoSitePlus^® at www.phosphosite.org.