Recombinant Human SERPINB9/PI-9 Protein (Human Cells, His Tag)

Serpin B9; also known as Cytoplasmic antiproteinase 3(CAP-3); is a cytoplasm protein which belongs to the large superfamily of serine proteinase inhibitors (serpins); which bind to and inactivate serine proteinases. Serpin B9 is an inhibitor of the granzyme B/perforin lytic pathway. It is expressed in normal mammary epithelial cells but not in most mammary carcinoma cell lines. These interactions are involved in many cellular processes; including coagulation; fibrinolysis; complement fixation; matrix remodeling; and apoptosis. Serpin-B9 expression in immune-privileged cells; APCs; and CTLs protects these cells against the actions of granzyme B; and when expressed in tumor cells or virally infected hepatocytes; confers resistance to killing by CTL and NK cells. Expression of increasing levels of Serpin-B9 in target cells may progressively inhibit immune surveillance by blocking NK and CTL-induced cytotoxicity through the perforin / granzyme pathway and then through the Fas / FasL pathway.