Proteinase 3 (PR3), also known as myeloblastin, Wegener autoantigen, PRTN3 and NP- 4, is one of the hematopoietic serine proteases localized in the primary granules of polymorphonuclear neutrophils (PMNs). The primary function of PR3 is recognized as to participate in direct intracellular killing of phagocytosed pathogens in phagolysosomes and degradation of extracellular matrix components at inflammatory sites. PR3 has also been proven to be able to process some pro-inflammatory cytokines, such as IL-1β, IL-18 and TNF-α, activate mitogen activated protein kinase (MAPK) signaling through proteinase activated receptor-1 (PAR1), and induce endothelial cell apoptosis through NF-κB signaling pathways. PR3 is identified as the target autoantigen of anti-neutrophil cytoplasmic autoantibodies (ANCA) in Wegener granulomatosis. Increased PR3 levels have been reported in patients with acute myocardial infarction, and in subjects with type 1 diabetes.
- References to Proteinase-3