DNA topoisomerase 2-binding protein 1 (IPR026993)

Short name: Topbp1

Family relationships

  • Secretoglobin (IPR016126)
    • DNA topoisomerase 2-binding protein 1 (IPR026993)


This entry includes DNA topoisomerase 2-binding protein 1/1A/1B (Topbp1/1A/1B).

Topbp1 is required for DNA replication and DNA repair. It down-regulates E2F1 activity and inhibits E2F1-dependent apoptosis during G1/S transition and after DNA damage. It also induces a large increase in the kinase activity of ATR [PMID: 14718568, PMID: 10498869, PMID: 11395493, PMID: 11714696, PMID: 12697828, PMID: 15075294, PMID: 16530042].

Topbp1A and 1B from Xenopus have dual roles in initiation of DNA replication and regulation of checkpoint responses [PMID: 12743046, PMID: 16923121]. They are required for DNA replication initiation but not for the formation of pre-replicative complexes or the elongation stages. Their role in checkpoint activation is independent of the DNA replication role. In response to DNA damage, they trigger the recruitment of checkpoint signaling proteins on chromatin, which activate the chk1 signaling pathway and block S-phase progression [PMID: 16923121].

Contributing signatures

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