CircuLex S100A10 ELISA Kit

S100A10, a member of the S100 family of Ca2+-binding proteins, is a dimeric protein composed of two 11-kDa subunits. The protein is cytosolic when present as a dimer. Typically, S100A10 is found in most cells bound to annexin A2 as the heterotetrameric (S100A10)2-(annexin A2)2 complex, AIIt, in a calcium-independent manner (1). The formation of AIIt results in the translocation of S100A10 to the plasma membrane (2). S100A10 has been shown to regulate plasma membrane ion channels (3, 4) as well as cytosolic phospholipase A2 (5). In addition to an intracellular distribution, it has also been established that the heterotetrameric form of S100A10 is present on the extracellular surface of many cells (6–9). Extracellularly, the S100A10 subunit functions as a plasminogen receptor (10, 11). The penultimate and ultimate carboxyl-terminal lysines of this subunit bind tPA and plasminogen (12) and regulate the stimulation of tPA-dependent plasminogen activation (13). Although S100A10 is expressed fairly ubiquitously in most cells and tissues, high levels of both p11 and A2 were found in 100% of anaplastic thyroid carcinomas, and correlated with their aggressive behavior (14). In a comprehensive study of S100 gene expression in over 300 primary breast cancers, both p11 (S100A10) and S100A11 were selectively upregulated in basal versus nonbasal breast cancer subtypes, but did not predict overall survival (15).