SERPINB9

SERPINB9 is a protein that in humans is encoded by the SERPINB9 gene. It is a member of the serpin family of proteins, a group of proteins that inhibit proteases and prevent them from carrying out their normal function. SERPINB9 is also known as Proteinase Inhibitor 9 (PI-9) and Serpin Peptidase Inhibitor, Clade B (Ovalbumin), Member 9.

Function

SERPINB9 is an intracellular serpin that is expressed in cytotoxic T lymphocytes (CTLs) and natural killer cells (NK cells). It is a potent inhibitor of granzyme B, a serine protease that is released by CTLs and NK cells to kill virally infected and tumor cells. By inhibiting granzyme B, SERPINB9 protects the immune cells from the damaging effects of the protease.

Clinical significance

Alterations in the SERPINB9 gene have been associated with various diseases. For example, a decrease in SERPINB9 expression has been observed in certain types of cancer, suggesting that the protein may play a role in tumor suppression. Additionally, mutations in the SERPINB9 gene have been linked to autoimmune diseases, as the protein is involved in regulating immune responses.

See also

• SERPIN
• Protease
• Cytotoxic T lymphocyte
• Natural killer cell
• Granzyme B