MutL ATPases are homologs of bacterial MutL, an ATPase that is part of the bacterial MutHLS pathway that repairs DNA mismatches. In eukaryotes, MutS-related heterodimers initiate repair by binding to base-base mismatches, small insertion/deletion loops or larger loops of unpaired nucleotides. MutL-related heterodimers are then involved in subsequent repair processes. (Adapted from PMID: 11920679.)