Diverse autoinhibitory mechanisms of FIIND-containing proteins: Insight into regulation of NLRP1 and CARD8 inflammasome.

Function-to-find domain (FIIND)-containing proteins, including NLRP1 and CARD8, are vital components of the inflammasome signaling pathway, critical for the innate immune response. These proteins exist in various forms due to autoproteolysis within the FIIND domain, resulting in full-length (FL), cl...

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Main Authors: Jingfan Zhou, Chengrong Liu, Xin Wang, Zhenshan Liu, Zizhen Ming, Yonggang Wang, Chunxia Wang, Qiming Liang
Format: Article
Language:English
Published: Public Library of Science (PLoS) 2025-01-01
Series:PLoS Pathogens
Online Access:https://doi.org/10.1371/journal.ppat.1012877
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author Jingfan Zhou
Chengrong Liu
Xin Wang
Zhenshan Liu
Zizhen Ming
Yonggang Wang
Chunxia Wang
Qiming Liang
author_facet Jingfan Zhou
Chengrong Liu
Xin Wang
Zhenshan Liu
Zizhen Ming
Yonggang Wang
Chunxia Wang
Qiming Liang
author_sort Jingfan Zhou
collection DOAJ
description Function-to-find domain (FIIND)-containing proteins, including NLRP1 and CARD8, are vital components of the inflammasome signaling pathway, critical for the innate immune response. These proteins exist in various forms due to autoproteolysis within the FIIND domain, resulting in full-length (FL), cleaved N-terminal (NT), and cleaved C-terminal (CT) peptides, which form autoinhibitory complexes in the steady state. However, the detailed mechanism remains elusive. Here, we found that both NLRP1 paralogs and CARD8 form two conserved autoinhibitory complexes involving NT-CT interactions and FL-CT interactions, but with distinct mechanisms. Specifically, the Linker3 region located between LRR and FIIND in murine NLRP1b (mNLRP1b) plays an essential role in forming the NT-CT autoinhibitory complexes, while the ZU5 of rat NLRP1 (rNLRP1) and CARD8 mediates their NT-CT interaction. In addition, we explored the involvement of the cellular protease dipeptidyl peptidases 9 (DPP9) in these complexes, revealing differential interactions and the significance of domain structure. Besides the FL-DPP9-CT complex, DPP9 interacts with NTs of mNLRP1b, rNLRP1, and CARD8 through their ZU5 subdomains, forming NT-DPP9-CT complex; however, DPP9 cannot bind to NTs of hNLRP1. Further functional assay indicated that although DPP9 is involved in the NT-CT complex of rodent NLRP1 and CARD8, it does not influence the inhibitory activity of NT on CT. Our study enhanced the understanding of the regulatory functions of FIIND-containing proteins in inflammasome autoinhibition and activation and underscored the complexity of their interactions within the immune response.
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spelling doaj-art-76d4ecfcd78b4bb592eddceadc0545042025-08-20T03:53:01ZengPublic Library of Science (PLoS)PLoS Pathogens1553-73661553-73742025-01-01211e101287710.1371/journal.ppat.1012877Diverse autoinhibitory mechanisms of FIIND-containing proteins: Insight into regulation of NLRP1 and CARD8 inflammasome.Jingfan ZhouChengrong LiuXin WangZhenshan LiuZizhen MingYonggang WangChunxia WangQiming LiangFunction-to-find domain (FIIND)-containing proteins, including NLRP1 and CARD8, are vital components of the inflammasome signaling pathway, critical for the innate immune response. These proteins exist in various forms due to autoproteolysis within the FIIND domain, resulting in full-length (FL), cleaved N-terminal (NT), and cleaved C-terminal (CT) peptides, which form autoinhibitory complexes in the steady state. However, the detailed mechanism remains elusive. Here, we found that both NLRP1 paralogs and CARD8 form two conserved autoinhibitory complexes involving NT-CT interactions and FL-CT interactions, but with distinct mechanisms. Specifically, the Linker3 region located between LRR and FIIND in murine NLRP1b (mNLRP1b) plays an essential role in forming the NT-CT autoinhibitory complexes, while the ZU5 of rat NLRP1 (rNLRP1) and CARD8 mediates their NT-CT interaction. In addition, we explored the involvement of the cellular protease dipeptidyl peptidases 9 (DPP9) in these complexes, revealing differential interactions and the significance of domain structure. Besides the FL-DPP9-CT complex, DPP9 interacts with NTs of mNLRP1b, rNLRP1, and CARD8 through their ZU5 subdomains, forming NT-DPP9-CT complex; however, DPP9 cannot bind to NTs of hNLRP1. Further functional assay indicated that although DPP9 is involved in the NT-CT complex of rodent NLRP1 and CARD8, it does not influence the inhibitory activity of NT on CT. Our study enhanced the understanding of the regulatory functions of FIIND-containing proteins in inflammasome autoinhibition and activation and underscored the complexity of their interactions within the immune response.https://doi.org/10.1371/journal.ppat.1012877
spellingShingle Jingfan Zhou
Chengrong Liu
Xin Wang
Zhenshan Liu
Zizhen Ming
Yonggang Wang
Chunxia Wang
Qiming Liang
Diverse autoinhibitory mechanisms of FIIND-containing proteins: Insight into regulation of NLRP1 and CARD8 inflammasome.
PLoS Pathogens
title Diverse autoinhibitory mechanisms of FIIND-containing proteins: Insight into regulation of NLRP1 and CARD8 inflammasome.
title_full Diverse autoinhibitory mechanisms of FIIND-containing proteins: Insight into regulation of NLRP1 and CARD8 inflammasome.
title_fullStr Diverse autoinhibitory mechanisms of FIIND-containing proteins: Insight into regulation of NLRP1 and CARD8 inflammasome.
title_full_unstemmed Diverse autoinhibitory mechanisms of FIIND-containing proteins: Insight into regulation of NLRP1 and CARD8 inflammasome.
title_short Diverse autoinhibitory mechanisms of FIIND-containing proteins: Insight into regulation of NLRP1 and CARD8 inflammasome.
title_sort diverse autoinhibitory mechanisms of fiind containing proteins insight into regulation of nlrp1 and card8 inflammasome
url https://doi.org/10.1371/journal.ppat.1012877
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