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Published on: January 20, 2023
TAK1 regulates caspase 8 activation and necroptotic signaling via multiple cell death checkpoints
Xiaoyun Guo1, Haifeng Yin1, Yi Chen1
1Department of Physiology and Biophysics, University of Washington, Seattle 98195, WA, USA.
Abstract:
Necroptosis has emerged as a new form of programmed cell death implicated in a number of pathological conditions such as ischemic injury, neurodegenerative disease, and viral infection. Recent studies indicate that TGFβ-activated kinase 1 (TAK1) is nodal regulator of necroptotic cell death, although the underlying molecular regulatory mechanisms are not well defined. Here we reported that TAK1 regulates necroptotic signaling as well as caspase 8-mediated apoptotic signaling through both NFκB-dependent and -independent mechanisms. Inhibition of TAK1 promoted TNFα-induced cell death through the induction of RIP1 phosphorylation/activation and necrosome formation. Further, inhibition of TAK1 triggered two caspase 8 activation pathways through the induction of RIP1-FADD-caspase 8 complex as well as FLIP cleavage/degradation. Mechanistically, our data uncovered an essential role for the adaptor protein TNF receptor-associated protein with death domain (TRADD) in caspase 8 activation and necrosome formation triggered by TAK1 inhibition. Moreover, ablation of the deubiqutinase CYLD prevented both apoptotic and necroptotic signaling induced by TAK1 inhibition. Finally, blocking the ubiquitin-proteasome pathway prevented the degradation of key pro-survival signaling proteins and necrosome formation. Thus, we identified new regulatory mechanisms underlying the critical role of TAK1 in cell survival through regulation of multiple cell death checkpoints. Targeting key components of the necroptotic pathway (e.g., TRADD and CYLD) and the ubiquitin-proteasome pathway may represent novel therapeutic strategies for pathological conditions driven by necroptosis.
Insights
Transforming Cell Death Research: New findings reveal TGFβ-activated kinase 1 (TAK1) regulates programmed cell death (necroptosis) and apoptosis. Targeting TAK1, TRADD, CYLD, and the ubiquitin-proteasome pathway offers novel therapeutic avenues for diseases involving necroptosis.
Area of Science:
- Cell Biology
- Molecular Biology
- Immunology
Background:
- Necroptosis, a form of programmed cell death, is increasingly recognized in various diseases.
- TGFβ-activated kinase 1 (TAK1) is a key regulator of necroptosis, but its precise mechanisms remain unclear.
- Understanding TAK1's role is crucial for developing new therapeutic strategies.
Purpose of the Study:
- To elucidate the molecular mechanisms by which TAK1 regulates necroptotic and apoptotic cell death.
- To identify novel signaling pathways and protein interactions involved in TAK1-mediated cell death.
- To explore potential therapeutic targets within the necroptosis pathway.
Main Methods:
- Investigated TAK1's role in TNFα-induced cell death.
- Analyzed RIP1 phosphorylation, necrosome formation, and caspase 8 activation.
- Utilized genetic ablation of TRADD and CYLD.
- Examined the impact of ubiquitin-proteasome pathway inhibition.
Main Results:
- TAK1 inhibition promotes TNFα-induced cell death via RIP1 activation and necrosome formation.
- TAK1 inhibition triggers caspase 8 activation through RIP1-FADD-caspase 8 complex and FLIP degradation.
- TRADD is essential for caspase 8 activation and necrosome formation upon TAK1 inhibition.
- CYLD ablation prevents both apoptotic and necroptotic signaling induced by TAK1 inhibition.
- Blocking the ubiquitin-proteasome pathway inhibits pro-survival protein degradation and necrosome formation.
Conclusions:
- TAK1 critically regulates cell survival by controlling multiple cell death checkpoints.
- TRADD and CYLD are key components in TAK1-mediated regulation of apoptosis and necroptosis.
- Targeting TRADD, CYLD, and the ubiquitin-proteasome pathway presents promising therapeutic strategies for necroptosis-driven pathologies.
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