PMS1

PMS1 protein homolog 1 is a protein that in humans is encoded by the PMS1 gene.

Function

The protein encoded by this gene was identified by its homology to a yeast protein involved in DNA mismatch repair. A role for this protein in mismatch repair has not been proven. However, the protein forms heterodimers with MLH1, a DNA mismatch repair protein, and some cases of hereditary nonpolyposis colorectal cancer have been found to have mutations in this gene.

Yeast studies

In the yeast Saccharomyces cerevisiae, the MSH2, MLH1 and PMS1 proteins are required for repair of DNA base pair mismatches, thus contributing to mutation avoidance. The MLH1 and PMS1 proteins physically associate, likely forming a heterodimer which then interacts with the MSH2 protein to form a ternary complex that acts in the initiation of DNA mismatch repair. The nucleotide sequence of the PMS1 gene from S. cerevisiae has a 2,712-base pair open reading frame and a predicted molecular mass of 103 kilodaltons. The deduced amino acid sequence encoded by the PMS1 gene of S. cerevisiae exhibits homology to the sequences of the mutL gene of the bacteria Salmonella typimurium and the hexB gene of the bacteria Streptococcus pneumoniae, and these two genes are also required for DNA mismatch repair in their respective organisms.