Dipeptidyl peptidase 9 (DPP9) is a ~98 kDa protein. Dipeptidyl peptidase that cleaves off N-terminal dipeptides from proteins having a Pro or Ala residue at position 2. Acts as a key inhibitor of caspase-1-dependent monocyte and macrophage pyroptosis in resting cells by preventing activation of NLRP1 and CARD8. Sequesters the cleaved C-terminal part of NLRP1 and CARD8, which respectively constitute the active part of the NLRP1 and CARD8 inflammasomes, in a ternary complex, thereby preventing their oligomerization and activation. The dipeptidyl peptidase activity is required to suppress NLRP1 and CARD8; however, neither NLRP1 nor CARD8 are bona fide substrates of DPP9, suggesting the existence of substrate(s) required for NLRP1 and CARD8 inhibition. 1. Qi, SY. et al. (2003) The Biochemical journal 373, 179-89. PMID: 126621552. Bjelke, JR. et al. (2006) The Biochemical journal 396, 391-9. PMID: 164759793. Geiss-Friedlander, R. et al. (2009) The Journal of biological chemistry 284, 27211-9. PMID: 196670704. Ross, B. et al. (2018) Proceedings of the National Academy of Sciences of the United States of America 115, E1437-E1445. PMID: 293827495. Zhong, FL. et al. (2018) The Journal of biological chemistry 293, 18864-18878. PMID: 302911417. Harapas, CR. et al. (2022) Science immunology 7, eabi4611. PMID: 361126938. Okondo, MC. et al. (2017) Nature chemical biology 13, 46-53. PMID: 278207989. Johnson, DC. et al. (2018) Nature medicine 24, 1151-1156. PMID: 29967349 | 
