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) (PubMed:23401855). 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 (PubMed:26215093). 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 (PubMed:23401855). Acts as a helicase in DNA mismatch repair (MMR) following DNA replication errors to unwind the mismatch containing DNA strand (PubMed:26300262). In addition, recruits MLH1, a component of the MMR complex, to chromatin (PubMed:26300262). The MCM8-MCM9 complex is dispensable for DNA replication and S phase progression (PubMed:23401855). Probably by regulating HR, plays a key role during gametogenesis (By similarity). ATP + H2O = ADP + H(+) + phosphate Component of the MCM8-MCM9 complex, which forms a hexamer composed of MCM8 and MCM9 (PubMed:23401855, PubMed:26300262, PubMed:26215093). Interacts with the DNA mismatch repair (MMR) complex composed at least of MSH2, MSH3, MSH6, PMS1 and MLH1 (PubMed:26300262). Interacts with MLH1; the interaction recruits MLH1 to chromatin (PubMed:26300262). Interacts with MSH2; the interaction recruits MCM9 to chromatin (PubMed:26300262). Interacts with MSH6 (PubMed:26300262). Interacts with the MRN complex composed of MRE11, RAD50 and NBN/NBS1; the interaction recruits the MRN complex to DNA damage sites (PubMed:26215093). Interacts with RAD51; the interaction recruits RAD51 to DNA damage sites (PubMed:23401855). Colocalizes to nuclear foci with RPA1 following DNA damage (PubMed:23401855). Localizes to double-stranded DNA breaks (PubMed:23401855). Recruited to chromatin by MSH2 (PubMed:26300262). The expression of isoform L and isoform M is cell cycle regulated: induced in S-phase, decreases through G2/M, and becomes constant through G1. The disease is caused by variants affecting the gene represented in this entry. Most abundant isoform. Belongs to the MCM family. Truncated N-terminus. Truncated C-terminus.