PI-9 Antibody (PI9-17): sc-57531

PI-9 Antibody (PI9-17) is a mouse monoclonal IgG1 antibody that detects PI-9 in mouse, rat, and human samples through applications such as western blotting (WB), immunoprecipitation (IP), immunofluorescence (IF), immunohistochemistry with paraffin-embedded sections (IHCP), and enzyme-linked immunosorbent assay (ELISA). PI-9 Antibody (PI9-17) is available in a non-conjugated form, providing flexibility for various experimental needs. Proteinase inhibitor-9 (PI-9), also known as cytoplasmic antiproteinase 3 (CAP3), is a crucial member of the serpin family, specifically the Ovalbumin family, and plays a significant role in regulating serine proteinase activity. PI-9 is predominantly expressed in the placenta, lung, and cytotoxic lymphocytes, where PI-9 serves as a potent inhibitor of granzyme B, a serine protease that mediates apoptosis. The inhibition of granzyme B prevents unwanted cell death during immune responses, particularly in cytotoxic T lymphocytes and natural killer cells. PI-9 also inhibits caspase-1 and, to a lesser extent, caspases 4 and 8, further contributing to a protective role against apoptosis. PI-9 is localized in the nuclei of human cytotoxic cells, endothelial cells, and epithelial cells, where PI-9 is involved in a unique nucleocytoplasmic transport mechanism that is sensitive to leptomycin B, indicating a nonconventional nuclear import pathway. PI-9 expression is rapidly induced by estrogen and is upregulated in response to inflammatory stimuli, enhancing cellular protection against granzyme B-induced apoptosis, especially during target cell killing. PI-9 has been implicated in various human and murine tumors, highlighting a potential role in cancer biology and therapy.

The preferred PI-9 antibody is PI-9 Antibody (F-6): sc-390501.