GZMK

Serine protease that initiates the GZMK pathway of the complement system, a cascade of proteins directly activated by CD8(+) T-cells that leads to phagocytosis and breakdown of pathogens and signaling that strengthens the adaptive immune system. GZMK is specifically secreted by CD8(+) T-cells and mediates both recognition and initiation steps of GZMK complement pathway. First acts as a pattern recognition receptor, which specifically recognizes and binds heparan sulfate glycosaminoglycans on the pathogen surface to drive opsonization. It then initiates the complement pathway cascade by catalyzing cleavage and activation of C2 and C4, the next components of the complement pathway. GZMK-mediated complement activation is an important contributor to tissue inflammation. Also able to cleave and activate F2R/PAR1 and PAR2/F2RL1, possibly promoting interleukin release. May also regulate apoptosis by catalyzing cleavage and activation of BID, thereby promoting cytochrome C release from mitochrondria..

Function from UniProtKB (P49863), read 2026-09-23. CC BY 4.0.