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Updated: Jun 6, 2026

A Chromatin Immunoprecipitation Assay to Identify Novel NFAT2 Target Genes in Chronic Lymphocytic Leukemia
Published on: December 4, 2018
TRAF2 phosphorylation promotes NF-κB-dependent gene expression and inhibits oxidative stress-induced cell death
Laiqun Zhang1, Ken Blackwell, Aliya Altaeva
1Department of Pathology, Carver College of Medicine, University of Iowa, 200 Hawkins Drive, Iowa City, IA 52242, USA.
Abstract:
Tumor necrosis factor α (TNF-α) receptor-associated factor 2 (TRAF2) regulates activation of the c-Jun N-terminal kinase (JNK)/c-Jun and the inhibitor of κB kinase (IKK)/nuclear factor κB (NF-κB) signaling cascades in response to TNF-α stimulation. Gene knockout studies have revealed that TRAF2 inhibits TNF-α-induced cell death but promotes oxidative stress-induced apoptosis. Here we report that TNF-α and oxidative stress both induce TRAF2 phosphorylation at serines 11 and 55 and that this dual phosphorylation promotes the prolonged phase of IKK activation while inhibiting the prolonged phase of JNK activation. Prolonged IKK activation trigged by TNF-α plays an essential role in efficient expression of a subset of NF-κB target genes but has no substantial role in TNF-α-induced cell death. On the other hand, TRAF2 phosphorylation in response to oxidative stress significantly promotes cell survival by inducing prolonged IKK activation and by inhibiting the prolonged phase of JNK activation. Notably, stable expression of phospho-null mutant TRAF2 in cancer cells leads to an increase in the basal and inducible JNK activation and B-cell lymphoma 2 (Bcl-2) phosphorylation. In addition, exposure of cells expressing phospho-null mutant TRAF2 to sublethal oxidative stress results in a rapid degradation of Bcl-2 and cellular inhibitor of apoptosis 1 as well as significantly increased cell death. These results suggest that TRAF2 phosphorylation is essential for cell survival under conditions of oxidative stress.
Insights
Tumor necrosis factor alpha (TNF-α) receptor-associated factor 2 (TRAF2) phosphorylation is crucial for cell survival. This modification promotes prolonged IKK activation and inhibits JNK activation, particularly under oxidative stress conditions.
Area of Science:
- Cellular signaling pathways
- Molecular biology
- Stress response mechanisms
Background:
- Tumor necrosis factor alpha (TNF-α) receptor-associated factor 2 (TRAF2) is a key regulator of TNF-α-induced signaling.
- TRAF2's role in TNF-α-induced cell death and oxidative stress-induced apoptosis is complex.
- Understanding TRAF2's post-translational modifications is vital for deciphering its diverse functions.
Purpose of the Study:
- To investigate the role of TRAF2 phosphorylation in response to TNF-α and oxidative stress.
- To elucidate how TRAF2 phosphorylation affects downstream signaling pathways, specifically IKK and JNK.
- To determine the impact of TRAF2 phosphorylation on cell survival and apoptosis.
Main Methods:
- Utilized gene knockout studies and phospho-null mutant TRAF2 expression in cancer cells.
- Analyzed TRAF2 phosphorylation at specific serine residues (S11 and S55) upon stimulation.
- Assessed the activation kinetics of IKK and JNK signaling cascades.
- Monitored the expression levels of apoptosis-related proteins like Bcl-2 and cellular inhibitor of apoptosis 1.
Main Results:
- Both TNF-α and oxidative stress induce TRAF2 phosphorylation at S11 and S55.
- TRAF2 phosphorylation promotes prolonged IKK activation and inhibits prolonged JNK activation.
- In oxidative stress, TRAF2 phosphorylation enhances cell survival by modulating IKK and JNK.
- Expression of phospho-null TRAF2 increases JNK activation and susceptibility to oxidative stress-induced cell death.
Conclusions:
- TRAF2 phosphorylation is essential for cell survival, particularly under oxidative stress.
- Dual phosphorylation of TRAF2 fine-tunes IKK and JNK signaling dynamics.
- TRAF2 phosphorylation acts as a critical switch controlling cell fate decisions in response to cellular stress.
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