DNA fragmentation factor 40 (IPR039729)

Short name: DFF40

Overlapping homologous superfamilies


Family relationships



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 45 kDa chaperone and inhibitor subunit (DFF45, also called ICAD-L) and a 40 kDa 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 nuclease activity is further activated by proteins such as histone H1, HMGB1/2, and topoisomerase II [PMID: 15723341].

This entry represents DFF40 (also known as DNA fragmentation factor subunit beta), which is an apoptotic nuclease that digests chromatin to yield 3'-hydroxyl groups and 5'-phosphate residues [PMID: 15723341].

GO terms

Biological Process

GO:0006309 apoptotic DNA fragmentation

Molecular Function

GO:0004536 deoxyribonuclease activity

Cellular Component

No terms assigned in this category.

Contributing signatures

Signatures from InterPro member databases are used to construct an entry.