TOPBP1

This gene encodes a binding protein which interacts with the C-terminal region of topoisomerase II beta. This interaction suggests a supportive role for this protein in the catalytic reactions of topoisomerase II beta through transient breakages of DNA strands. [provided by RefSeq, Jul 2008]

TOPBP1 Gene(Protein Coding) DNA Topoisomerase II Binding Protein 1

Required for DNA replication. Plays a role in the rescue of stalled replication forks and checkpoint control. Binds double-stranded DNA breaks and nicks as well as single-stranded DNA. Recruits the SWI/SNF chromatin remodeling complex to E2F1-responsive promoters. Down-regulates E2F1 activity and inhibits E2F1-dependent apoptosis during G1/S transition and after DNA damage. Induces a large increase in the kinase activity of ATR (PubMed:16530042).

Biological Process cellular response to DNA damage stimulus Source:UniProtKB1 Publication
Biological Process DNA metabolic process Source:ProtInc1 Publication
Biological Process DNA repair Source:UniProtKB1 Publication
Biological Process DNA replication initiation Source:GO_Central1 Publication
Biological Process homologous recombination Source:ComplexPortal1 Publication
Biological Process mitotic DNA replication checkpoint signaling Source:GO_Central1 Publication
Biological Process mitotic G2 DNA damage checkpoint signaling Source:GO_Central1 Publication
Biological Process response to ionizing radiation Source:UniProtKB1 Publication

Nucleus
Cytoplasm, cytoskeleton, microtubule organizing center, centrosome
Cytoplasm, cytoskeleton, spindle pole
Chromosome
Detected on unpaired autosomes in meiotic prophase cells. Detected on X and Y chromosomes during later stages of prophase. Colocalizes with ATR and H2AX at unsynapsed chromosome cores during prophase (By similarity).
Has a uniform nuclear distribution during G phase. Colocalizes with BRCA1 at stalled replication forks during S phase. In mitotic cells it colocalizes with BRCA1 at spindle poles and centrosomes during metaphase and anaphase. Detected in discrete foci together with PML and numerous DNA repair enzymes after DNA damage by alkylating agents, UV or gamma irradiation. Localizes to sites of DNA damage in a H2AX- independent manner.

Phosphorylated on serine and threonine residues in response to X-ray irradiation.
Ubiquitinated and degraded by the proteasome. X-ray irradiation reduces ubiquitination.