DNA Repair Protein XRCC1 Stimulates Activity of DNA Polymerase λ under Conditions of Microphase Separation.
Int J Mol Sci
; 25(13)2024 Jun 25.
Article
in En
| MEDLINE
| ID: mdl-39000034
ABSTRACT
Non-membrane compartments or biomolecular condensates play an important role in the regulation of cellular processes including DNA repair. Here, an ability of XRCC1, a scaffold protein involved in DNA base excision repair (BER) and single-strand break repair, to form protein-rich microphases in the presence of DNA duplexes was discovered. We also showed that the gap-filling activity of BER-related DNA polymerase λ (Pol λ) is significantly increased by the presence of XRCC1. The stimulation of the Pol λ activity was observed only at micromolar XRCC1 concentrations, which were well above the nanomolar dissociation constant determined for the XRCC1-Pol λ complex and pointed to the presence of an auxiliary stimulatory factor in addition to protein-protein interactions. Indeed, according to dynamic light scattering measurements, the stimulation of the Pol λ activity by XRCC1 was coupled with microphase separation in a protein-DNA mixture. Fluorescence microscopy revealed colocalization of Pol λ, XRCC1, and gapped DNA within the microphases. Thus, stimulation of Pol λ activity is caused both by its interaction with XRCC1 and by specific conditions of microphase separation; this phenomenon is shown for the first time.
Key words
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
DNA Polymerase beta
/
DNA Repair
/
X-ray Repair Cross Complementing Protein 1
Limits:
Humans
Language:
En
Journal:
Int J Mol Sci
/
Int. j. mol. sci. (Online)
/
International journal of molecular sciences (Online)
Year:
2024
Document type:
Article
Affiliation country:
Country of publication: