Download MendeleyThe human RIF1-Long isoform interacts with BRCA1 to promote recombinational fork repair under DNA replication stress.
Dong, Q., Day, M., Saito, Y., Parker, E., Watts, L.P., Kanemaki, M.T., Oliver, A.W., Pearl, L.H., Hiraga, S.I., Donaldson, A.D.(2025) Nat Commun 16: 5820-5820
- PubMed: 40595496
- DOI: https://doi.org/10.1038/s41467-025-60817-y
- Primary Citation of Related Structures:
8RS8 - PubMed Abstract:
RIF1 is a multifunctional protein that regulates DNA replication and repair. RIF1-deficient cells are hypersensitive to DNA replication stress. Of the two alternatively spliced RIF1 isoforms, called RIF1-Short and RIF1-Long, the RIF1-Long isoform is more capable than RIF1-Short in supporting cell recovery from replication stress. Examining replication stress resistance mechanisms specific to RIF1-Long, we find that prolonged replication stress unexpectedly induces interaction of RIF1-Long with BRCA1. Mechanistically, a phosphorylated SPKF motif unique to the RIF1-Long isoform binds the tandem BRCT domain of BRCA1. BRCA1-RIF1-Long interaction is strongly down-regulated through dephosphorylation by RIF1-associated Protein Phosphatase 1. BRCA1-RIF1-Long interaction requires ATR signaling, and occurs predominantly during S phase. Loss of RIF1-Long impairs the formation of RAD51 foci, and reduces the efficiency of homology-mediated repair at broken replication forks. In summary, our investigation establishes RIF1-Long as a new functional binding partner of the BRCA1-BRCT domain, crucial to protect cells from extended DNA replication stress by enabling RAD51-dependent repair of broken replication forks.
Organizational Affiliation:
Chromosome & Cellular Dynamics Section, Institute of Medical Sciences, University of Aberdeen, Aberdeen, UK.
