Mechanism of Replication Fork Reversal and Protection by Human RAD51 and RAD51 Paralogs

Halder, Swagata; Sanchez, Aurore; Ranjha, Lepakshi; Taglialatela, Angelo; Reginato, Giordano; Ceppi, Ilaria; Acharya, Ananya; Anand, Roopesh; Ciccia, Alberto; Ćejka, Petr

doi:10.2139/ssrn.3742313

Cited by 1 publication

(2 citation statements)

References 95 publications

(158 reference statements)

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“…In vertebrates, a motif called TR2 28 , CTRD 29 or CTRB 30 that binds to RAD51 was detected in the C-terminal disordered region of BRCA2. It has a stabilizing effect on RAD51-DNA complexes, counteracting BRCs 31,32 . Research on this C-terminal site was focused on S3291, which can be phosphorylated by CDKs at the G2-M transition 28,[30][31][32][33][34][35] .…”

Section: Introductionmentioning

confidence: 99%

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DMC1 and RAD51 bind FxxA and FxPP motifs of BRCA2 via two separate interfaces

Miron,

Legrand,

van Rossum-Fikkert

et al. 2023

Preprint

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In vertebrates, the BRCA2 protein is essential for meiotic and somatic homologous recombination (HR) due to its interaction with RAD51 and DMC1 strand exchange proteins (recombinases). The interaction is mediated by FxxA and FxPP motifs, whose defining feature is the invariant phenylalanine. The FxxA motifs, present in the eight BRC repeats in the central region of BRCA2, compete with the FxxA motif of the linker region of RAD51 that is responsible for recombinase self-oligomerization. In vitro, BRCs disrupt RAD51 nucleoprotein filaments, but they are essential for RAD51 function in the context of the full-length BRCA2 protein. The role of the FxPP motifs is poorly studied but they also contribute to BRCA2 function in cells. In particular, the C-terminal TR2/CTRB domain of BRCA2, which contains an FxPP motif, is required for stabilization of RAD51 filament and replication fork protection. We recently found that deletion of the BRCA2 PhePP domain, which contains another FxPP motif, disrupts DMC1 but not RAD51 function in meiosis. Here we provide a mechanistic explanation for this phenotype by solving the crystal structure of the complex between DMC1 and the PhePP domain of BRCA2. Our structure reveals that, despite sequence similarity, the A-motifs (FxxA) and P-motifs (FxPP) bind to distinct and contiguous sites on the recombinases. The PhePP P-motif binding site is mostly located at the ATPase domain surface of a DMC1 monomer, but also extends to the linker region of the adjacent monomer, thus engaging two adjacent protomers in the DMC1 oligomer. Our structural analysis provides a mechanism explaining how PhePP favors the formation of the DMC1 nucleoprotein filament and stabilizes it. It corroborates and explains the stabilizing effect of the P-motif from BRCA2 TR2/CTRB on RAD51.

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Section: Introductionmentioning

confidence: 99%

“…It has a stabilizing effect on RAD51-DNA complexes, counteracting BRCs 31,32 . Research on this C-terminal site was focused on S3291, which can be phosphorylated by CDKs at the G2-M transition 28,[30][31][32][33][34][35] .…”

Section: Introductionmentioning

confidence: 99%