hMSH3 and hMSH6 interact with PCNA and colocalize with it to replication foci.
Proliferating cell nuclear antigen (PCNA) has been implicated in eukaryotic postreplicative mismatch correction, but the nature of its interaction with the repair machinery remained enigmatic. We now show that PCNA binds to the human mismatch binding factors hMutSalpha and hMutSbeta via their hMSH6 and hMSH3 subunits, respectively. The N-terminal domains of both proteins contain the highly conserved PCNA-binding motif Qxx[LI]xx[FF]. A variant of hMutSalpha, lacking this motif because of deletion of 77 N-terminal residues of the hMSH6 subunit, no longer was able to interact with PCNA in vitro and failed to restore mismatch repair in hMSH6-deficient cells. Colocalization of PCNA and hMSH6 or hMSH3 to replication foci implies an intimate link between replication and mismatch correction. We postulate that PCNA plays a role in repair initiation by guiding the mismatch repair proteins to free termini in the newly replicated DNA strands.
Kleczkowska
H E
HE
Institute of Medical Radiobiology of the University of Zürich and the Paul Scherrer Institute, CH-8008 Zürich, Switzerland.
Marra
G
G
Lettieri
T
T
Jiricny
J
J
D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D000818:Animals; D020137:Base Pair Mismatch; D015153:Blotting, Western; D002460:Cell Line; D050759:Cyclin-Dependent Kinase Inhibitor p21; D016213:Cyclins / Q000378:metabolism; D004247:DNA / Q000378:metabolism; D004260:DNA Repair; D004261:DNA Replication; D004268:DNA-Binding Proteins / Q000378:metabolism*; D004305:Dose-Response Relationship, Drug; D004591:Electrophoresis, Polyacrylamide Gel; D019084:Fluorescent Antibody Technique, Indirect; D005816:Genetic Complementation Test; D006367:HeLa Cells; D006801:Humans; D008856:Microscopy, Fluorescence; D008969:Molecular Sequence Data; D027425:ATP-Binding Cassette, Sub-Family C Proteins; D000074081:MutS Homolog 3 Protein; D009154:Mutation; D010455:Peptides / Q000737:chemistry; D011233:Precipitin Tests; D018809:Proliferating Cell Nuclear Antigen / Q000378:metabolism*; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D011994:Recombinant Proteins / Q000378:metabolism; D014162:Transfection
D050759:Cyclin-Dependent Kinase Inhibitor p21; D016213:Cyclins; D004247:DNA; D004268:DNA-Binding Proteins; D027425:ATP-Binding Cassette, Sub-Family C Proteins; D000074081:MutS Homolog 3 Protein; D010455:Peptides; D018809:Proliferating Cell Nuclear Antigen; D011994:Recombinant Proteins; C493956:CDKN1A protein, human; C094443:G-T mismatch-binding protein; C078444:MSH3 protein, human; C421109:multidrug resistance-associated protein 1