Component of the MCM8-MCM9 complex, a complex involved in the repair of double-stranded DNA breaks (DBSs) and DNA interstrand cross-links (ICLs) by homologous recombination (HR). Required for DNA resection by the MRE11-RAD50-NBN/NBS1 (MRN) complex by recruiting the MRN complex to the repair site and by promoting the complex nuclease activity. Probably by regulating the localization of the MRN complex, indirectly regulates the recruitment of downstream effector RAD51 to DNA damage sites including DBSs and ICLs. Acts as a helicase in DNA mismatch repair (MMR) following DNA replication errors to unwind the mismatch containing DNA strand. In addition, recruits MLH1, a component of the MMR complex, to chromatin. The MCM8-MCM9 complex is dispensable for DNA replication and S phase progression. Probably by regulating HR, plays a key role during gametogenesis. ATP + H2O = ADP + H(+) + phosphate Component of the MCM8-MCM9 complex, which forms a hexamer composed of MCM8 and MCM9. Interacts with the DNA mismatch repair (MMR) complex composed at least of MSH2, MSH3, MSH6, PMS1 and MLH1. Interacts with MLH1; the interaction recruits MLH1 to chromatin. Interacts with MSH2; the interaction recruits MCM9 to chromatin. Interacts with MSH6. Interacts with the MRN complex composed of MRE11, RAD50 and NBN/NBS1; the interaction recruits the MRN complex to DNA damage sites. Interacts with RAD51; the interaction recruits RAD51 to DNA damage sites. Colocalizes to nuclear foci with RPA1 following DNA damage. Localizes to double-stranded DNA breaks. Recruited to chromatin by MSH2. Belongs to the MCM family.