Protein Domain : DNA fragmentation factor 45kDa, C-terminal IPR027296

Type	Homologous_superfamily
Description	One of the hallmarks of the terminal stages of apoptosis is internucleosomal DNA breakdown. DNA fragmentation factor (DFF) and endonuclease G (Endo G) are responsible for this process. DFF exists in the nucleus as a heterodimer composed of a 45kDa chaperoneand inhibitor subunit (DFF45, also called ICAD-L) and a 40kDa latent nuclease subunit (DFF40/CAD). Apoptotic activation of caspase-3 or -7 results in the cleavage of DFF45 and release of active DFF40 nuclease, which forms homo-oligomers. DFF40's nucleaseactivity is further activated by proteins such as histone H1, HMGB1/2, and topoisomerase II []. The C-terminal region of DNA fragmentation factor 45kDa (DFF-C) consists of four α-helices, which are folded in a helix-packing arrangement, with alpha-2 and alpha-3 packing against a long C-terminal helix (alpha-4) [ ]. The main function of this region is the inhibition of DFF40 by binding to its C-terminal catalytic domain through ionic interactions, thereby inhibiting the fragmentation of DNA in the apoptotic process. In addition to blocking the DNase activity of DFF40, the C-terminal region of DFF45 is also important for the DFF40-specific folding chaperone activity, as demonstrated by the ability of DFF45 to refold DFF40 [].
Short Name	DFF-C