Reverse hierarchical DED assembly in the cFLIP-procaspase-8 and cFLIP-procaspase-8-FADD complexes

Abstract cFLIP, a master anti-apoptotic regulator, targets the FADD-induced DED complexes of procaspase-8 in death receptor and ripoptosome signaling pathways. Several tumor cells maintain relatively high levels of cFLIP in achieving their immortality. However, understanding the three-dimensional re...

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Main Authors: Chao-Yu Yang, Yi-Chun Tseng, Yi-Fan Tu, Bai-Jiun Kuo, Li-Chung Hsu, Chia-I Lien, You-Sheng Lin, Yin-Ting Wang, Yen-Chen Lu, Tsung-Wei Su, Yu-Chih Lo, Su-Chang Lin
Format: Article
Language:English
Published: Nature Portfolio 2024-10-01
Series:Nature Communications
Online Access:https://doi.org/10.1038/s41467-024-53306-1
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Summary:Abstract cFLIP, a master anti-apoptotic regulator, targets the FADD-induced DED complexes of procaspase-8 in death receptor and ripoptosome signaling pathways. Several tumor cells maintain relatively high levels of cFLIP in achieving their immortality. However, understanding the three-dimensional regulatory mechanism initiated or mediated by elevated levels of cFLIP has been limited by the absence of the atomic coordinates for cFLIP-induced DED complexes. Here we report the crystal plus cryo-EM structures to uncover an unconventional mechanism where cFLIP and procaspase-8 autonomously form a binary tandem DED complex, independent of FADD. This complex gains the ability to recruit FADD, thereby allosterically modulating cFLIP assembly and partially activating caspase-8 for RIPK1 cleavage. Our structure-guided mutagenesis experiments provide critical insights into these regulatory mechanisms, elucidating the resistance to apoptosis and necroptosis in achieving immortality. Finally, this research offers a unified model for the intricate bidirectional hierarchy-based processes using multiprotein helical assembly to govern cell fate decisions.
ISSN:2041-1723