DNA repair complex

Definition

Target type: cellularcomponent

A protein complex involved in DNA repair processes including direct reversal, base excision repair, nucleotide excision repair, photoreactivation, bypass, double-strand break repair pathway, and mismatch repair pathway. [GOC:bhm, PMID:17217467, PMID:20551348, PMID:22749910, PMID:24192350]

DNA repair complexes are intricate molecular machines that orchestrate the intricate process of mending damaged DNA, safeguarding genomic integrity and preventing cellular dysfunction. These complexes are assembled from a diverse array of proteins, each contributing unique functionalities to the repair process. The specific composition of a repair complex can vary depending on the type of DNA damage encountered and the cellular context. However, common components include:

1. **DNA damage recognition proteins:** These proteins act as the first responders, identifying and binding to the site of DNA damage. Examples include the MRE11-RAD50-NBS1 (MRN) complex, which recognizes double-strand breaks, and the XPC-RAD23B complex, which identifies bulky DNA adducts.
2. **Scaffold proteins:** These proteins act as the structural backbone of the repair complex, bringing together various repair enzymes and facilitating their coordinated activity. Examples include the 9-1-1 complex, which is involved in checkpoint activation, and the RAD51 protein, which plays a crucial role in homologous recombination repair.
3. **DNA helicases:** These enzymes unwind the DNA helix, providing access to the damaged region and allowing other repair proteins to interact with the DNA. Examples include the BLM and WRN helicases, which are involved in DNA unwinding during recombination and nucleotide excision repair, respectively.
4. **Exonucleases:** These enzymes remove damaged nucleotides from the DNA strand, creating a clean template for repair. Examples include the EXO1 and FEN1 exonucleases, which play roles in various repair pathways.
5. **DNA polymerases:** These enzymes synthesize new DNA strands, using the undamaged strand as a template to fill in the gaps created by the exonucleases. Examples include DNA polymerase delta and epsilon, which are involved in replication and repair, and DNA polymerase beta, which is specialized for base excision repair.
6. **Ligases:** These enzymes seal the newly synthesized DNA strand to the existing DNA strand, completing the repair process. Examples include DNA ligase I and IV, which are involved in various repair pathways.

In addition to these core components, repair complexes can also recruit other proteins, such as histone modifiers, chromatin remodelers, and signaling molecules, depending on the specific type of damage and the cellular context. The coordinated action of these proteins ensures the accurate and efficient repair of DNA damage, preserving genomic integrity and maintaining cellular function.'
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Proteins (5)

Compounds (71)