CD59
Description
CD59, also known as protectin, is a glycosylphosphatidylinositol (GPI)-anchored protein expressed on the surface of various cells. It plays a vital role in regulating the complement system, a crucial part of the immune system that eliminates pathogens and damaged cells. CD59 acts as a potent inhibitor of the membrane attack complex (MAC), the final step in the complement cascade. This prevents uncontrolled MAC formation on host cells, thus safeguarding them from self-destruction. Its expression is ubiquitous, appearing on red blood cells, platelets, lymphocytes, and other cell types, highlighting its critical role in maintaining immune homeostasis.
Associated Diseases
- Paroxysmal nocturnal hemoglobinuria (PNH): Mutations in the gene encoding CD59 lead to impaired complement regulation, resulting in excessive MAC formation and hemolysis.
- Atypical hemolytic uremic syndrome (aHUS): In some cases, mutations in CD59 are associated with aHUS, a rare disease characterized by hemolytic anemia, thrombocytopenia, and kidney failure.
- Other diseases: Dysregulation of CD59 expression has been linked to various autoimmune disorders, such as rheumatoid arthritis and systemic lupus erythematosus.
Did you know?
CD59 was initially identified as a factor that protected erythrocytes from complement-mediated lysis.
