Open AccessNF-κB inhibits T-cell activation-induced, p73-dependent cell death by induction of MDM2
Author(s) -
V. Busuttil,
Nathalie Droin,
Laura L. McCormick,
Francesca Bernassola,
Eleonora Candi,
Gerry Melino,
Douglas R. Green
Publication year - 2010
Publication title -
proceedings of the national academy of sciences of the united states of america
Language(s) - English
Resource type - Journals
eISSN - 1091-6490
pISSN - 0027-8424
DOI - 10.1073/pnas.1006163107
Subject(s) - apoptosis , microbiology and biotechnology , programmed cell death , nf κb , signal transduction , mdm2 , transcription factor , biology , nfkb1 , cell growth , iκb kinase , cancer research , chemistry , gene , biochemistry
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.