Annexin V, also known as PAP-1 or Lipocortin V, is a ~30 kDa protein that binds to phospholipids in a
calcium-dependent manner (1). All annexins contain a putative PKC binding site, but only annexin V
has been identified as an inhibitor of this pathway (2). It may also signal, by direct interaction with
VEGFR2 receptor, in the regulation of vascular endothelial cell proliferation (3). Annexin V
preferentially binds phosphatidylserine, in competition with prothrombin, leading to inhibition of blood
coagulation at sites of injury preceding contact between lipid components and coagulation factors that
initiate thrombosis (4-6). The ability of Annexin V to bind specifically and robustly to hosphatidylserine
makes it an attractive reagent in detecting apoptotic cells (7). Annexin V is inducible by glucocorticoids
and can be phosphorylated by tyrosine and serine/threonine kinases (8). It isthought to
blockproduction of mediators of inflammation, such as prostaglandins and leukotrienes by inhibiting
the release of arachidonic acid from membranes by phospholipase A2 (8).
