Postmeiotic Segregation Increased Protein 2 (PMS2)

PMS2is involved in DNA mismatch repair. The protein forms a heterodimer with MLH1 and this complex interacts with MSH2 bound to mismatched bases. Defects in this gene are associated with hereditary nonpolyposis colorectal cancer, with Turcot syndrome, and are a cause of supratentorial primitive neuroectodermal tumors. Alternatively spliced transcript variants have been observed.

Microsequence analysis demonstrated both of these proteins to be homologs of bacterial MutL, with the former corresponding to the human MLH1 product and the latter to the product of human PMS2 or a closely related gene. The 1:1 molar stoichiometry of the 2 polypeptides and their hydrodynamic behavior indicated formation of a heterodimer.