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

ABSTRACT: NF-?B 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 I?B kinase (IKK?) are unable to activate NF-?B, and rapidly undergo apoptosis upon activation. NF-?B activation following T-cell receptor engagement induces the expression of Mdm2 through interaction with NF-?B sites in its P1 promoter, and enforced expression of Mdm2 protected T cells deficient for NF-?B activation from activation-induced cell death. In T cells with intact NF-?B 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-?B-induced Mdm2, which blocks Bim-dependent apoptosis through binding and inhibition of p73.

SUBMITTER: Busuttil V 

PROVIDER: S-EPMC2964227 | biostudies-literature | 2010 Oct

REPOSITORIES: biostudies-literature