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DNA fragmentation factor, 40kDa, beta polypeptide (caspase-activated DNase)
Protein DFFB PDB 1ibx.png
PDB rendering based on 1ibx.
Available structures
PDB Ortholog search: PDBe, RCSB
Symbols DFFB ; CAD; CPAN; DFF-40; DFF2; DFF40
External IDs OMIM601883 MGI1196287 HomoloGene3241 GeneCards: DFFB Gene
RNA expression pattern
PBB GE DFFB 206752 s at tn.png
More reference expression data
Species Human Mouse
Entrez 1677 13368
Ensembl ENSG00000169598 ENSMUSG00000029027
UniProt O76075 O54788
RefSeq (mRNA) NM_001004285 NM_007859
RefSeq (protein) NP_001269598 NP_031885
Location (UCSC) Chr 1:
3.77 – 3.8 Mb
Chr 4:
153.96 – 153.98 Mb
PubMed search [1] [2]
DNA fragmentation factor 40 kDa
PDB 1v0d EBI.jpg
crystal structure of caspase-activated dnase (cad)
Symbol DFF40
Pfam PF09230
InterPro IPR015311
SCOP 1v0d

DNA fragmentation factor subunit beta is a protein that in humans is encoded by the DFFB gene.[1][2][3]

Apoptosis is a cell death process that removes toxic and/or useless cells during mammalian development. The apoptotic process is accompanied by shrinkage and fragmentation of the cells and nuclei and degradation of the chromosomal DNA into nucleosomal units. DNA fragmentation factor (DFF) is a heterodimeric protein of 40-kD (DFFB) and 45-kD (DFFA) subunits. DFFA is the substrate for caspase-3 and triggers DNA fragmentation during apoptosis. DFF becomes activated when DFFA is cleaved by caspase-3. The cleaved fragments of DFFA dissociate from DFFB, the active component of DFF. DFFB has been found to trigger both DNA fragmentation and chromatin condensation during apoptosis. Multiple alternatively spliced transcript variants encoding distinct isoforms have been found for this gene, but the biological validity of some variants has not been determined.[3]


DFFB has been shown to interact with DFFA.[4][5]


  1. ^ Liu X, Zou H, Slaughter C, Wang X (May 1997). "DFF, a heterodimeric protein that functions downstream of caspase-3 to trigger DNA fragmentation during apoptosis". Cell 89 (2): 175–84. doi:10.1016/S0092-8674(00)80197-X. PMID 9108473. 
  2. ^ Halenbeck R, MacDonald H, Roulston A, Chen TT, Conroy L, Williams LT (Aug 1998). "CPAN, a human nuclease regulated by the caspase-sensitive inhibitor DFF45". Curr Biol 8 (9): 537–40. doi:10.1016/S0960-9822(98)79298-X. PMID 9560346. 
  3. ^ a b "Entrez Gene: DFFB DNA fragmentation factor, 40kDa, beta polypeptide (caspase-activated DNase)". 
  4. ^ Ewing, Rob M; Chu Peter, Elisma Fred, Li Hongyan, Taylor Paul, Climie Shane, McBroom-Cerajewski Linda, Robinson Mark D, O'Connor Liam, Li Michael, Taylor Rod, Dharsee Moyez, Ho Yuen, Heilbut Adrian, Moore Lynda, Zhang Shudong, Ornatsky Olga, Bukhman Yury V, Ethier Martin, Sheng Yinglun, Vasilescu Julian, Abu-Farha Mohamed, Lambert Jean-Philippe, Duewel Henry S, Stewart Ian I, Kuehl Bonnie, Hogue Kelly, Colwill Karen, Gladwish Katharine, Muskat Brenda, Kinach Robert, Adams Sally-Lin, Moran Michael F, Morin Gregg B, Topaloglou Thodoros, Figeys Daniel (2007). "Large-scale mapping of human protein-protein interactions by mass spectrometry". Mol. Syst. Biol. (England) 3 (1): 89. doi:10.1038/msb4100134. PMC 1847948. PMID 17353931. 
  5. ^ McCarty, J S; Toh S Y; Li P (Oct 1999). "Study of DFF45 in its role of chaperone and inhibitor: two independent inhibitory domains of DFF40 nuclease activity". Biochem. Biophys. Res. Commun. (UNITED STATES) 264 (1): 176–80. doi:10.1006/bbrc.1999.1497. ISSN 0006-291X. PMID 10527860. 

Further reading[edit]