NF-κB inhibits T-cell activation-induced, p73-dependent cell death by induction of MDM2

• Published in: Proceedings of the National Academy of Sciences - PNAS 2010-10, Vol.107 (42), p.18061-18066
• Main Authors: Busuttil, Valere, Droin, Nathalie, McCormick, Laura, Bernassola, Francesca, Candi, Eleonora, Melino, Gerry, Green, Douglas R
• Format: Article
• Language: English
• Subjects: Annexins; Apoptosis; Biological Sciences; Cell death; Chalconoids; Gene expression regulation; Messenger RNA; Reverse transcriptase polymerase chain reaction; T cell antigen receptors; T lymphocytes; Transcription factors
• ISSN: 0027-8424; 1091-6490
• DOI: 10.1073/pnas.1006163107

NF-κB is a key transcription factor involved in the regulation of T-cell activation and proliferation upon engagement of the T-cell receptor (TCR). T cells that lack the IκB kinase (IKKβ) are unable to activate NF-κB, and rapidly undergo apoptosis upon activation. NF-κB activation following T-cell receptor engagement induces the expression of Mdm2 through interaction with NF-κB sites in its P1 promoter, and enforced expression of Mdm2 protected T cells deficient for NF-κB activation from activation-induced cell death. In T cells with intact NF-κB signaling, ablation or pharmacologic inhibition of Mdm2 resulted in activation-induced apoptosis. Mdm2 coprecipitates with p73 in activated T cells, and apoptosis induced by inhibition of Mdm2 was p73-dependent. Further, Bim was identified as a p73 target gene required for cell death induced by Mdm2 inhibition, and a p73-responsive element in intron 1 of Bim was characterized. Our results demonstrate a pathway for survival of activated T cells through NF-κB–induced Mdm2, which blocks Bim-dependent apoptosis through binding and inhibition of p73.