Tumor necrosis factor alpha (TNF-alpha) signaling gives rise to a numb
er of events, including activation of transcription factor NF-kappa B
and programmed cell death (apoptosis). Previous studies of TNF-alpha s
ignaling have suggested that these two events occur independently. The
sensitivity and kinetics of TNF-alpha-induced apoptosis are shown to
be enhanced in a number of cell types expressing a dominant-negative I
kappa B alpha (I kappa B alpha M). These findings suggest that a nega
tive feedback mechanism results from TNF-alpha signaling in which NF-k
appa B activation suppresses the signals for cell death.