PCNA and Msh2-Msh6 activate an Mlh1-Pms1 endonuclease pathway required for Exo1-independent mismatch repair

Eva M Goellner; Catherine E Smith; Christopher S Campbell; Hans Hombauer; Arshad Desai; Christopher D Putnam; Richard D Kolodner

doi:10.1016/j.molcel.2014.04.034

PCNA and Msh2-Msh6 activate an Mlh1-Pms1 endonuclease pathway required for Exo1-independent mismatch repair

Mol Cell. 2014 Jul 17;55(2):291-304. doi: 10.1016/j.molcel.2014.04.034. Epub 2014 Jun 26.

Authors

Eva M Goellner¹, Catherine E Smith¹, Christopher S Campbell¹, Hans Hombauer², Arshad Desai³, Christopher D Putnam⁴, Richard D Kolodner⁵

Affiliations

¹ Ludwig Institute for Cancer Research, University of California, San Diego School of Medicine, La Jolla, CA 92093-0669, USA.
² Ludwig Institute for Cancer Research, University of California, San Diego School of Medicine, La Jolla, CA 92093-0669, USA; German Cancer Research Center (DKFZ), 69120 Heidelberg, Germany.
³ Ludwig Institute for Cancer Research, University of California, San Diego School of Medicine, La Jolla, CA 92093-0669, USA; Department of Cellular and Molecular Medicine, University of California, San Diego School of Medicine, La Jolla, CA 92093-0669, USA.
⁴ Ludwig Institute for Cancer Research, University of California, San Diego School of Medicine, La Jolla, CA 92093-0669, USA; Department of Medicine, University of California, San Diego School of Medicine, La Jolla, CA 92093-0669, USA.
⁵ Ludwig Institute for Cancer Research, University of California, San Diego School of Medicine, La Jolla, CA 92093-0669, USA; Department of Medicine, University of California, San Diego School of Medicine, La Jolla, CA 92093-0669, USA; Department of Cellular and Molecular Medicine, University of California, San Diego School of Medicine, La Jolla, CA 92093-0669, USA; Moores-UCSD Cancer Center, University of California, San Diego School of Medicine, La Jolla, CA 92093-0669, USA; Institute of Genomic Medicine, University of California, San Diego School of Medicine, La Jolla, CA 92093-0669, USA. Electronic address: rkolodner@ucsd.edu.

Abstract

Genetic evidence has implicated multiple pathways in eukaryotic DNA mismatch repair (MMR) downstream of mispair recognition and Mlh1-Pms1 recruitment, including Exonuclease 1 (Exo1)-dependent and -independent pathways. We identified 14 mutations in POL30, which encodes PCNA in Saccharomyces cerevisiae, specific to Exo1-independent MMR. The mutations identified affected amino acids at three distinct sites on the PCNA structure. Multiple mutant PCNA proteins had defects either in trimerization and Msh2-Msh6 binding or in activation of the Mlh1-Pms1 endonuclease that initiates excision during MMR. The latter class of mutations led to hyperaccumulation of repair intermediate Mlh1-Pms1 foci and were enhanced by an msh6 mutation that disrupted the Msh2-Msh6 interaction with PCNA. These results reveal a central role for PCNA in the Exo1-independent MMR pathway and suggest that Msh2-Msh6 localizes PCNA to repair sites after mispair recognition to activate the Mlh1-Pms1 endonuclease for initiating Exo1-dependent repair or for driving progressive excision in Exo1-independent repair.

Publication types

Research Support, N.I.H., Extramural
Research Support, Non-U.S. Gov't

MeSH terms

Adaptor Proteins, Signal Transducing / metabolism*
Carrier Proteins / metabolism*
DNA Mismatch Repair
DNA, Fungal / genetics
DNA-Binding Proteins / metabolism*
Enzyme Activation
Exodeoxyribonucleases / metabolism*
Models, Molecular
MutL Protein Homolog 1
MutL Proteins
MutS Homolog 2 Protein / metabolism*
Mutation, Missense
Proliferating Cell Nuclear Antigen / chemistry
Proliferating Cell Nuclear Antigen / genetics*
Proliferating Cell Nuclear Antigen / metabolism
Protein Binding
Protein Interaction Domains and Motifs
Protein Multimerization
Protein Stability
Saccharomyces cerevisiae / enzymology*
Saccharomyces cerevisiae / genetics
Saccharomyces cerevisiae Proteins / chemistry
Saccharomyces cerevisiae Proteins / genetics*
Saccharomyces cerevisiae Proteins / metabolism*
Signal Transduction

Substances

Adaptor Proteins, Signal Transducing
Carrier Proteins
DNA, Fungal
DNA-Binding Proteins
MLH1 protein, S cerevisiae
MSH6 protein, S cerevisiae
PMS1 protein, S cerevisiae
POL30 protein, S cerevisiae
Proliferating Cell Nuclear Antigen
Saccharomyces cerevisiae Proteins
Exodeoxyribonucleases
exodeoxyribonuclease I
MSH2 protein, S cerevisiae
MutL Protein Homolog 1
MutL Proteins
MutS Homolog 2 Protein

Abstract

Publication types

MeSH terms

Substances

Grants and funding