During apoptosis, various stimuli activate a protease cascade of caspases that eventually cause degradation of chromosomal DNA. DFF45 (DNA fragmentation factor 45) is a down-stream regulator of DNA degradation (DFF40). DFF40 is an apoptotic DNase with a high specific activity that exists in an inactive complex with DFF45 in living cells. Cleavage of DFF45, which is mediated by caspase-3, leads to DFF40 release where it then enters nucleus to function as a nuclease. DFF45 may inhibit the DNAse activity of DFF40 and its nuclear translocation. Activation of DFF40 causes DNA degradation, a hallmark of apoptosis.
