IEX-1L, an apoptosis inhibitor involved in NF-κB-mediated cell survival

Transcription factors of the nuclear factor-kappa B/rel (NF-kappa B) family may be important in cell survival by regulating unidentified, anti-apoptotic genes. One such gene that protects cells from apoptosis induced by pas or tumor necrosis factor type or (TNF), IEX-1L, is described here. Its transcription induced by TNF was decreased in cells with defective NF-kappa B activation, rendering them sensitive to TNF-induced apoptosis, which was abolished by transfection with IEX-1L. In support, overexpression of antisense IEX-1L partially blocked TNF-induced expression of IEX-1L and sensitized normal cells to killing. This study demonstrates a key role of IEX-1L in cellular resistance to TNF-induced apoptosis.