protein DBF4 homolog B (activator of S phase kinase-like protein 1, ASK-like protein 1, Dbf4-related factor 1, chiffon homolog B, DBF4B, ASKL1, DRF1)

Function

• regulatory subunit for CDC7 which activates its kinase activity thereby playing a central role in DNA replication & cell proliferation
• required for progression of S & M phases
• the complex CDC7-DBF4B selectively phosphorylates MCM2 subunit at Ser-40 & then is involved in regulating the initiation of DNA replication during cell cycle
• forms a complex with CDC7
• note that CDC7 forms distinct complex either with DBF4/DBF4A or DBF4B, such complexes are stable upon replication stress
• phosphorylated

Structure

• contains 1 BRCT domain
• contains 1 DBF4-type Zn+2 finger

Compartment

• nucleus
• predominantly found in soluble fraction but not in the chromatin-bound fraction

Alternative splicing

named isoforms=4

Expression

• widely expressed
• highly expressed in testis
• expression increases as cells enter in S phase through G2/M phase
• short half-life (at protein level)

More general terms

• nuclear protein
• zinc finger protein

Database

• UniProt: http://www.uniprot.org/uniprot/Q8NFT6.html