Structural highlights
Function
CASP1_HUMAN Thiol protease that cleaves IL-1 beta between an Asp and an Ala, releasing the mature cytokine which is involved in a variety of inflammatory processes. Important for defense against pathogens. Cleaves and activates sterol regulatory element binding proteins (SREBPs). Can also promote apoptosis.[1] [2]
Publication Abstract from PubMed
Several interleukin-1 (IL-1) family members, including IL-1beta and IL-18, require processing by inflammasome-associated caspases to unleash their activities. Here, we unveil, by cryoelectron microscopy (cryo-EM), two major conformations of the complex between caspase-1 and pro-IL-18. One conformation is similar to the complex of caspase-4 and pro-IL-18, with interactions at both the active site and an exosite (closed conformation), and the other only contains interactions at the active site (open conformation). Thus, pro-IL-18 recruitment and processing by caspase-1 is less dependent on the exosite than the active site, unlike caspase-4. Structure determination by nuclear magnetic resonance uncovers a compact fold of apo pro-IL-18, which is similar to caspase-1-bound pro-IL-18 but distinct from cleaved IL-18. Binding sites for IL-18 receptor and IL-18 binding protein are only formed upon conformational changes after pro-IL-18 cleavage. These studies show how pro-IL-18 is selected as a caspase-1 substrate, and why cleavage is necessary for its inflammatory activity.
Structural transitions enable interleukin-18 maturation and signaling.,Dong Y, Bonin JP, Devant P, Liang Z, Sever AIM, Mintseris J, Aramini JM, Du G, Gygi SP, Kagan JC, Kay LE, Wu H Immunity. 2024 May 8:S1074-7613(24)00220-6. doi: 10.1016/j.immuni.2024.04.015. PMID:38733997[3]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
References
- ↑ Alnemri ES, Fernandes-Alnemri T, Litwack G. Cloning and expression of four novel isoforms of human interleukin-1 beta converting enzyme with different apoptotic activities. J Biol Chem. 1995 Mar 3;270(9):4312-7. PMID:7876192
- ↑ Feng Q, Li P, Leung PC, Auersperg N. Caspase-1zeta, a new splice variant of the caspase-1 gene. Genomics. 2004 Sep;84(3):587-91. PMID:15498465 doi:http://dx.doi.org/S0888-7543(04)00161-2
- ↑ Dong Y, Bonin JP, Devant P, Liang Z, Sever AIM, Mintseris J, Aramini JM, Du G, Gygi SP, Kagan JC, Kay LE, Wu H. Structural transitions enable interleukin-18 maturation and signaling. Immunity. 2024 May 8:S1074-7613(24)00220-6. PMID:38733997 doi:10.1016/j.immuni.2024.04.015
