Annexin A1 Human ELISA test

The annexin superfamily is composed of 12 members in humans, characterized by the unique Ca2+-binding-site architecture, which enables them to peripherally attach to negatively charged membrane surfaces. Annexin A1 (AnxA1), also known as annexin I or lipocortin I, was characterized as a glucocorticoid-regulated anti-inflammatory protein. This 37-kDa protein is comprised of a homologous core region of 310 amino acid residues, representing almost 90% of the structure, attached to a unique N-terminal region. AnxA1 is a Ca2+-regulated phospholipid-binding protein. To mediate membrane binding, Ca2+ ions can induce a conformational change that leads to the exposure of the bioactive N-terminal domain. The different functions of AnxA1 lie within the unique N-terminus. AnxA1 is expressed in several tissues and involved in different cell processes including cell survival, proliferation, apoptosis, differentiation and migration. AnxA1 can be nuclear, cytoplasmic and/or membrane-associated. Depending on the human tissue/cell line, AnxA1 can be cleaved at different positions by different proteases. The membrane-associated AnxA1 can be proteolytically cleaved to become accessible to its cognate partners, the formyl-peptide receptors (FPRs). The AnxA1/FPR complex has been found to be involved in inflammation, neuroendocrine system regulation, skeletal muscle differentiation and cancer progression. To date, FPRs are the only known receptors of externalized AnxA1. As these receptors can be activated or silenced by a variety of synthetic ligands, they represent an attractive family of pharmacological targets.