Characterization of a highly conserved binding site of Mlh1 required for exonuclease I-dependent mismatch repair.
Mlh1 is an essential factor of mismatch repair (MMR) and meiotic recombination. It interacts through its C-terminal region with MutL homologs and proteins involved in DNA repair and replication. In this study, we identified the site of yeast Mlh1 critical for the interaction with Exo1, Ntg2, and Sgs1 proteins, designated as site S2 by reference to the Mlh1/Pms1 heterodimerization site S1. We show that site S2 is also involved in the interaction between human MLH1 and EXO1 or BLM. Binding at this site involves a common motif on Mlh1 partners that we called the MIP-box for the Mlh1 interacting protein box. Direct and specific interactions between yeast Mlh1 and peptides derived from Exo1, Ntg2, and Sgs1 and between human MLH1 and peptide derived from EXO1 and BLM were measured with K(d) values ranging from 8.1 to 17.4 microM. In Saccharomyces cerevisiae, a mutant of Mlh1 targeted at site S2 (Mlh1-E682A) behaves as a hypomorphic form of Exo1. The site S2 in Mlh1 mediates Exo1 recruitment in order to optimize MMR-dependent mutation avoidance. Given the conservation of Mlh1 and Exo1 interaction, it may readily impact Mlh1-dependent functions such as cancer prevention in higher eukaryotes.
Dherin
Claudine
C
CEA, IRCM, UMR217, Radiobiologie Moléculaire et Cellulaire, Fontenay aux Roses, France.
Gueneau
Emeric
E
Francin
Mathilde
M
Nunez
Marcela
M
Miron
Simona
S
Liberti
Sascha Emilie
SE
Rasmussen
Lene Juel
LJ
Zinn-Justin
Sophie
S
Gilquin
Bernard
B
Charbonnier
Jean-Baptiste
JB
Boiteux
Serge
S
D048868:Adaptor Proteins, Signal Transducing / Q000737:chemistry* / Q000378:metabolism*; D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D000596:Amino Acids / Q000378:metabolism; D001665:Binding Sites; D002151:Calorimetry; D017124:Conserved Sequence; D053843:DNA Mismatch Repair; D019281:Dimerization; D005090:Exodeoxyribonucleases / Q000378:metabolism*; D006801:Humans; D008958:Models, Molecular; D008969:Molecular Sequence Data; D000070957:MutL Protein Homolog 1; D016297:Mutagenesis, Site-Directed; D009154:Mutation / Q000235:genetics; D009687:Nuclear Proteins / Q000737:chemistry* / Q000378:metabolism*; D010455:Peptides / Q000378:metabolism; D011485:Protein Binding; D012441:Saccharomyces cerevisiae / Q000201:enzymology; D029701:Saccharomyces cerevisiae Proteins / Q000737:chemistry* / Q000378:metabolism*; D017384:Sequence Deletion; D013045:Species Specificity; D013329:Structure-Activity Relationship; D020798:Two-Hybrid System Techniques
D048868:Adaptor Proteins, Signal Transducing; D000596:Amino Acids; C088859:MLH1 protein, S cerevisiae; C501486:MLH1 protein, human; D009687:Nuclear Proteins; D010455:Peptides; D029701:Saccharomyces cerevisiae Proteins; D005090:Exodeoxyribonucleases; C028450:exodeoxyribonuclease I; D000070957:MutL Protein Homolog 1