The CIP2A-TOPBP1 axis facilitates mitotic DNA repair via MiDAS and MMEJ.

ABSTRACT: Mitotic DNA double-strand breaks (DSBs) accumulate in response to replication stress or BRCA1/2 deficiency posing a significant threat to genome stability as repair by non-homologous end-joining (NHEJ) and homologous recombination (HR) is largely inactivated in mitosis. Instead, mitotic cells rely on alternative repair processes such as microhomology-mediated end-joining (MMEJ) and mitotic DNA synthesis (MiDAS). How these mitotic DNA repair pathways are functionally regulated remains unclear. Here we reveal that the CIP2A-TOPBP1 complex plays an essential regulatory role by facilitating the mitotic recruitment of both SMX complex components and Polθ to mitotic chromatin. Recruitment of the SMX complex components is driven by CDK1-dependent phosphorylation of SLX4 at Thr1260, enabling its i

SUBMITTER: Martin PR 

PROVIDER: S-EPMC12661054 | biostudies-literature | 2025 Nov

REPOSITORIES: biostudies-literature