Nuclear factor-KB (NF-K B) and activator protein 1 (AP-1) are well-characterized ubiquitously expressed transcription factors that play important roles in the response to cellular stress situations. In unstimulated resting cells, NF-K B and AP-1 are inactive. These transcription factors are induced by a great variety of stimuli and conditions that represent internal or external stress situations for the cells. These include pathological stimuli, such as viruses, bacteria, oxidative stress, hypoxia, and inflammatory mediators as well as internal cellular stress (e.g., endoplasmic reticulum overload) (1 –7 ).
