TAF1 aggravates ferroptosis by promoting the ubiquitin-mediated degradation of nuclear GPX4

Area of Science:

• Cellular Biology
• Molecular Oncology
• Biochemistry

Background:

• Ferroptosis is a regulated cell death pathway crucial in cancer.
• Glutathione peroxidase 4 (GPX4) inhibits ferroptosis, with nuclear localization (nGPX4) poorly understood.
• Understanding nGPX4 regulation is key to developing ferroptosis-based cancer therapies.

Purpose of the Study:

• To elucidate the regulatory mechanisms of nuclear GPX4 (nGPX4).
• To identify key proteins involved in nGPX4 regulation and ferroptosis.
• To investigate the dual role of TAF1 in ferroptosis based on TP53 status.

Main Methods:

• Phosphorylation assays to study nGPX4 modification by TAF1.
• Ubiquitination and proteasomal degradation assays.
• Western blotting and gene expression analysis (SLC7A11) in TP53-mutant and wild-type cells.

Main Results:

• TAF1 directly phosphorylates nGPX4, promoting its K11-linked ubiquitination and proteasomal degradation.
• This TAF1-mediated degradation of nGPX4 promotes ferroptosis in TP53-mutant cells.
• In TP53-wild-type cells, TAF1 phosphorylates TP53, leading to MDM2-mediated degradation and increased SLC7A11 expression, thus inhibiting ferroptosis.

Conclusions:

• TAF1 is a critical regulator of nGPX4 stability and ferroptosis.
• TAF1 exhibits dual, context-dependent roles in ferroptosis, promoting it in TP53-mutant cells and inhibiting it in TP53-wild-type cells.
• These findings reveal a novel regulatory axis impacting ferroptosis and cancer cell fate.