PMS2, also named as PMSL2, belongs to the DNA mismatch repair mutL/hexB family. It is a component of the post-replicative DNA mismatch repair system (MMR). It heterodimerizes with MLH1 to form MutL alpha. MulL alpha (MLH1-PMS2) interacts physically with the clamp loader subunits of DNA polymerase III, suggesting that it may play a role to recruit the DNA polymerase III to the site of the MMR. It also implicated in DNA damage signaling, a process which induces cell cycle arrest and can lead to apoptosis in case of major DNA damages. (PMID: 16873062, PMID: 18206974) Defects in PMS2 are the cause of hereditary non-polyposis colorectal cancer type 4 (HNPCC4). Defects in PMS2 are a cause of mismatch repair cancer syndrome (MMRCS).