The NF-kB-dependent signaling pathways are essential components of cellular response to stress. Mammalian family of NF-kB consists of five NF-kB/Rel proteins, which are subunits of the NF-kB transcription factor, and four IkB proteins, which are their specific inhibitors. Activation of NF-kB requires degradation of IkB, which allows nuclear translocation of NF-kB and its binding to cisacting DNA regulatory elements. NF-kB transcription factors regulate expression of numerous genes, which are involved in cell proliferation, apoptosis, immune response and inflammatory response.

One typical biochemical processes of programmed cell death (apoptosis) is the degradation of DNA takes place in two successive stages. Degradation fragments of chromatin to oligonukleosomowych is preceded by cutting the chromosome fragments with a length of 50 (or more) of thousands of base pairs. The DNA fragmentation is associated chromatin condensation observed in cells undergoing apoptosis. One of the nuclease responsible for DNA fragmentation during apoptosis is DFF40/CAD. DFF40/CAD nuclease activation is catalyzed by caspase-3 inhibitor nuclease degradation, protein DFF45/ICAD.