Affinage

MLH1

DNA mismatch repair protein Mlh1 · UniProt P40692

Length
756 aa
Mass
84.6 kDa
Annotated
2026-06-10
100 papers in source corpus 30 papers cited in narrative 30 extracted findings
Cross-family judge vs UniProt: Affinage preferred faithfulness: 7/8 claims corpus-supported (88%)

Mechanistic narrative

Synthesis pass · prose summary of the discoveries below

MLH1 is the shared scaffold subunit of MutL complexes that orchestrate DNA mismatch repair (MMR) and meiotic recombination, partnering with PMS1/PMS2 in mitotic cells to correct replication errors and with MLH3 to promote crossing over (PMID:8066446, PMID:8673133). It is recruited to mispaired DNA by the MutSα sensor through direct contacts with the MSH2 connector domain and the MSH6 ATPase/core domain, establishing MLH1 (not its partner subunit) as the MutS-interacting subunit of MutLα (PMID:36122480). Within the heterodimer MLH1 provides the primary non-sequence-specific DNA-binding activity through positively charged residues in its N-terminal domain and binds ATP with high affinity, undergoing ATP-induced conformational changes; both subunit ATPase activities and a conserved Mlh1 linker motif are required for the latent PMS1/PMS2 endonuclease that incises the error-containing strand (PMID:11575920, PMID:12682353, PMID:10082584, PMID:11154280, PMID:11897781, PMID:36215471). Productive function depends on correct MLH1:PMS1 stoichiometry, since MLH1 excess drives nonfunctional homodimer formation and a dominant mutator phenotype (PMID:10082584, PMID:11154280). Downstream incision is coupled to PCNA, which activates the Mlh1-Pms1 endonuclease in an Exo1-independent pathway with MutS-dependent loading (PMID:24981171); in meiosis the MutLγ (MLH1-MLH3) endonuclease nicks DNA near recombination intermediates and is stimulated by MutSγ (MSH4-MSH5), EXO1, RFC and PCNA to direct crossover formation (PMID:32015124, PMID:32814904). Beyond catalysis, MLH1 acts as a signaling scaffold: it is required for alkylation-induced apoptosis and couples damage to a c-Abl/MEKK1/MKK4/JNK/c-Jun MAPK cascade in an ATM-dependent manner (PMID:13679151, PMID:17804421), and by restraining EXO1-mediated excision it prevents excess single-strand DNA, cytoplasmic DNA release, and cGAS-STING-driven innate immune activation and apoptosis (PMID:33338427). MLH1 abundance and activity are tightly controlled: CK2 phosphorylation of S477 inactivates MMR (PMID:30136313), HDAC6 deacetylation blocks MutSα-MutLα assembly (PMID:30770470), SIRT2 deacetylation at K402/443/461 prevents MLH1 ubiquitination and degradation (PMID:40668890), destabilizing missense variants are cleared by chaperone-assisted proteasomal degradation with co-degradation of PMS1/PMS2 (PMID:31697235), and MLH1 transcription is modulated by an ERβ-bound promoter element, a CTCF-bound -35 kb enhancer, and chromate-induced G9a H3K9 dimethylation (PMID:28404976, PMID:29898989, PMID:19376149). Germline HNPCC-mimicking missense mutations separate mitotic and meiotic functions and can selectively abolish partner interactions such as FANCJ/BACH1 binding (PMID:12618391, PMID:20978114).

Mechanistic history

Synthesis pass · year-by-year structured walk · 20 steps
  1. 1994 High

    Established that MLH1 acts together with PMS1 and the MutSα sensor at the initiation of MMR, defining MLH1 as a complex-forming MMR factor rather than a standalone enzyme.

    Evidence Physical association and DNA-binding/co-complex biochemistry in S. cerevisiae

    PMID:8066446

    Open questions at the time
    • Did not resolve which subunit binds DNA or which carries catalytic activity
    • Stoichiometry and conformational dynamics of the ternary complex undefined
  2. 1996 High

    Showed that MLH1 has dual physiological roles — correcting replication errors (preventing microsatellite instability) and enabling meiotic crossing over — by knocking out the gene in mice.

    Evidence Mouse gene knockout with microsatellite instability assay and cytological localization on meiotic chromosomes

    PMID:8673133

    Open questions at the time
    • Did not define the molecular partner mediating meiotic crossover (later MLH3)
    • Mechanism linking MMR machinery to crossover resolution unresolved
  3. 1999 High

    Demonstrated that functional MMR requires balanced MLH1:PMS1 stoichiometry, since MLH1 excess forms inactive homodimers and a dominant mutator phenotype.

    Evidence Yeast overexpression, mutation rate assays, and analytical ultracentrifugation of purified protein

    PMID:10082584 PMID:11154280

    Open questions at the time
    • Did not establish whether homodimers form in human cells
    • Structural basis of heterodimer vs homodimer preference not resolved
  4. 2002 High

    Defined the catalytic logic of MutLα by showing both subunit ATPase activities are needed and that MLH1 binds ATP more tightly and undergoes larger ATP-induced conformational change than PMS2.

    Evidence In vitro reconstituted MMR with active-site mutants and limited proteolysis

    PMID:11897781

    Open questions at the time
    • How ATP-driven conformational change activates the endonuclease was not yet known
    • Coupling between ATPase cycle and DNA scanning undefined
  5. 2003 High

    Localized the heterodimer's primary DNA-binding activity to the MLH1 N-terminal domain, distinguishing the functional contributions of the two subunits.

    Evidence In vitro DNA binding of purified NTD fragments plus yeast mutator assays

    PMID:12682353

    Open questions at the time
    • Did not connect NTD binding to endonuclease positioning
    • Cooperative/dual-duplex binding mechanism addressed separately
  6. 2003 High

    Separated MLH1's mitotic and meiotic functions genetically and connected MLH1 dosage to the apoptosis-versus-mutagenesis decision after alkylation damage.

    Evidence Yeast missense allele panel for meiotic phenotypes; gene-targeted mouse cells with caspase-3 and mutation readouts

    PMID:12618391 PMID:13679151

    Open questions at the time
    • Molecular pathway linking MLH1 to caspase-3 activation not defined here
    • Why distinct alleles separate crossover, heteroduplex repair, and segregation unclear
  7. 2003 Medium

    Identified c-MYC as a physical MLH1 partner whose elevation modestly increases frameshift mutation rate, hinting at MMR modulation by an oncogenic factor.

    Evidence Yeast two-hybrid, GST pulldown, co-IP from tumor cells, HGPRT mutation assay

    PMID:12584560

    Open questions at the time
    • Functional effect on mutation rate is modest and from a single lab
    • Mechanism by which c-MYC binding alters MMR unresolved
  8. 2007 Medium

    Positioned MLH1 as a damage-signaling scaffold by showing it cooperates with ATM and c-Abl to activate the MEKK1/MKK4/JNK/c-Jun cascade after alkylation.

    Evidence Co-IP, kinase assays, siRNA/inhibitor studies in MLH1-deficient cells

    PMID:17804421

    Open questions at the time
    • Single-lab co-IP/inhibitor evidence without reconstitution
    • Direct molecular contacts within the MLH1-MEKK1-c-Abl complex undefined
  9. 2009 Medium

    Clarified MutLα nuclear delivery, showing MLH1's bipartite NLS provides redundancy that ensures heterodimer import.

    Evidence Confocal imaging of transfected NLS mutants and complementation

    PMID:19148896

    Open questions at the time
    • Import receptor identity not determined
    • Single-lab localization study
  10. 2009 Medium

    Showed MLH1 expression is epigenetically silenced via G9a-mediated H3K9 dimethylation at its promoter upon chromate exposure, reversible by ascorbate.

    Evidence ChIP for histone marks and RT-PCR with pharmacological rescue

    PMID:19376149

    Open questions at the time
    • No direct G9a knockdown confirmation
    • Causal chain from Cr(VI) to G9a recruitment incomplete
  11. 2010 Medium

    Linked an HNPCC MLH1 mutation (L607H) to loss of FANCJ/BACH1 helicase binding, connecting a specific interaction to MMR signaling kinetics and drug resistance.

    Evidence Co-IP, MMR signaling and apoptosis assays with clinical mutation analysis

    PMID:20978114

    Open questions at the time
    • Single-lab co-IP plus cellular assays
    • Structural basis of the MLH1-FANCJ interface unknown
  12. 2014 High

    Revealed PCNA as a direct activator of the Mlh1-Pms1 endonuclease in an Exo1-independent MMR pathway, with MutSα required to localize PCNA to repair sites.

    Evidence Yeast PCNA mutant screen, endonuclease assays, live-cell focus analysis

    PMID:24981171

    Open questions at the time
    • Structural mechanism of PCNA-mediated endonuclease activation not resolved
    • Relationship between Exo1-dependent and -independent pathways in vivo unclear
  13. 2017 Medium

    Identified transcriptional and checkpoint roles, showing ERβ directly activates MLH1 transcription and that MLH1 is required for the Cr(VI)-induced G2/M checkpoint.

    Evidence ChIP/reporter assays with MMR readouts and xenografts; MMR-deficient vs proficient checkpoint comparison

    PMID:28404976 PMID:29137397

    Open questions at the time
    • Single-lab studies
    • Direct molecular link between MLH1 and checkpoint kinase activation not defined
  14. 2018 High

    Established post-translational and enhancer-level control of MLH1: CK2 phosphorylation of S477 switches off MMR, HDAC6 deacetylation blocks MutSα-MutLα assembly, and a CTCF-bound -35 kb enhancer drives expression.

    Evidence In vitro kinase/deacetylase assays, MS site mapping, reconstituted MMR and complex assembly assays, 3C/CRISPR enhancer deletion

    PMID:29898989 PMID:30136313 PMID:30770470

    Open questions at the time
    • Cell-cycle regulation of S477 phosphorylation correlative
    • How acetylation status integrates with phosphorylation not addressed
  15. 2019 Medium

    Explained loss of function for many disease variants through structural destabilization and chaperone-assisted proteasomal degradation that co-degrades PMS1/PMS2.

    Evidence Cellular stability assays with proteasome inhibitors and in silico saturation mutagenesis

    PMID:31697235

    Open questions at the time
    • Specific E3 ligase and chaperones not identified
    • Single-lab study
  16. 2020 High

    Defined MLH1's meiotic catalytic role and a non-canonical innate-immune role: MutLγ (MLH1-MLH3) is a MutSγ/EXO1/RFC/PCNA-stimulated endonuclease directing crossovers, and MLH1 loss unleashes EXO1 to trigger cGAS-STING activation.

    Evidence Reconstitution of MutLγ endonuclease with purified components and yeast genetics; MLH1-knockout cells with ssDNA/RPA, cytoplasmic DNA and cGAS-STING readouts

    PMID:32015124 PMID:32814904 PMID:33338427

    Open questions at the time
    • Structural basis of MutLγ strand-targeting unresolved
    • In vivo contribution of cGAS-STING activation to MMR-deficient tumor immunity from single models
  17. 2021 Medium

    Identified FAN1 as an MLH1-binding factor that, via a conserved SPYF motif, restricts MSH3-mediated MLH1 recruitment to limit CAG repeat expansion.

    Evidence Co-IP, SPYF motif mutagenesis, and CAG repeat expansion assays

    PMID:34469738

    Open questions at the time
    • Single-lab co-IP and functional assay
    • Quantitative balance between FAN1 sequestration and nuclease activity unclear
  18. 2022 High

    Resolved the recruitment and activation logic of MutLα: MLH1 is the subunit that engages MSH2/MSH6, and a conserved Mlh1 linker motif distant from active sites is required for endonuclease function.

    Evidence Reconstituted MMR and binding assays with domain mutagenesis; peptide inhibition and yeast genetics

    PMID:36122480 PMID:36215471

    Open questions at the time
    • How the long-range linker motif allosterically licenses incision unknown
    • Structure of the recruited MutSα-MutLα-DNA complex not determined
  19. 2024 Medium

    Connected MLH1 stability to disease biology: wild-type HTT stabilizes MLH1 via MutLα, and SIRT2 deacetylation at K402/443/461 blocks MLH1 ubiquitination, with loss of either route triggering EXO1 hyperactivity and cGAS-STING-dependent apoptosis.

    Evidence Co-IP, MLH1 stability and EXO1 excision assays, cGAS-STING readouts; in vitro SIRT2 deacetylase and ubiquitination assays

    PMID:38498709 PMID:40668890

    Open questions at the time
    • Single-lab co-IP and functional assays
    • Interplay between SIRT2/HDAC6/CK2 modifications on the same MLH1 pool unresolved
  20. 2025 Medium

    Validated the MLH1-PMS2 dimerization interface as a druggable target by using an AI-designed binder that suppresses MutLα assembly and boosts prime editing efficiency.

    Evidence Computational protein design, binding assays, and prime editing efficiency measurements in cells and mice

    PMID:40769155

    Open questions at the time
    • Interface characterization is computational
    • Off-target effects of MMR suppression in vivo not fully characterized

Open questions

Synthesis pass · forward-looking unresolved questions
  • How the multiple post-translational modifications, partner interactions, and conformational states integrate to switch MLH1 between MMR, meiotic, signaling, and innate-immune functions on a single structural framework remains unresolved.
  • No high-resolution structure of the human MutSα-MutLα-DNA-PCNA assembly captured during incision
  • Hierarchy and crosstalk among CK2, HDAC6, SIRT2, and ubiquitination on MLH1 undefined
  • Mechanism coupling endonuclease activation to ATPase cycling not structurally resolved

Mechanism profile

Synthesis pass · controlled-vocabulary classification · explore literature graph →
Molecular activity
GO:0140096 catalytic activity, acting on a protein 3 GO:0140097 catalytic activity, acting on DNA 3 GO:0003677 DNA binding 2 GO:0060090 molecular adaptor activity 2 GO:0140657 ATP-dependent activity 2
Localization
GO:0005634 nucleus 1 GO:0005694 chromosome 1
Pathway
R-HSA-73894 DNA Repair 4 R-HSA-1474165 Reproduction 3 R-HSA-5357801 Programmed Cell Death 3 R-HSA-168256 Immune System 2 R-HSA-162582 Signal Transduction 1
Partners
EXO1FAN1MLH3MSH2MSH6PCNAPMS1PMS2
Complex memberships
MutLα (MLH1-PMS2)MutLβ (MLH1-PMS1)MutLγ (MLH1-MLH3)

Evidence

Reading pass · 30 per-paper findings extracted from the source corpus
Year Finding Method Journal Conf PMIDs
1994 Yeast MLH1 and PMS1 proteins physically associate (possibly as a heterodimer) and together bind a MSH2-heteroduplex complex containing a G-T mismatch, forming a ternary MSH2-MLH1-PMS1 complex during initiation of DNA mismatch repair. Physical association and DNA-binding experiments in S. cerevisiae; biochemical co-complex analysis Science High 8066446
1996 Mouse Mlh1 is required for DNA mismatch repair (loss causes microsatellite instability) and for meiotic crossing over; Mlh1 localizes to sites of crossing over on meiotic chromosomes, and Mlh1-deficient mice of both sexes are infertile with spermatocytes arresting in first meiotic division. Gene knockout in mice; cytological localization on meiotic chromosomes; microsatellite instability assay Nature genetics High 8673133
1999 Overexpression of wild-type MLH1 in yeast causes a strong mutator phenotype by imbalancing MLH1:PMS1 levels, leading to formation of nonfunctional MLH1 homodimers; Mlh1 can homodimerize in solution (Kd ~3.14 µM), ~36-fold weaker than MLH1-PMS1 heterodimerization. Yeast overexpression; mutation rate assays; analytical ultracentrifugation of purified protein; missense mutations disrupting Mlh1-Pms1 interaction Molecular and cellular biology High 10082584 11154280
2001 The yeast Mlh1-Pms1 heterodimer binds duplex DNA with high cooperativity (requiring >241 bp duplex), non-sequence-specifically via ionic contacts, and can simultaneously contact two separate DNA duplexes; AFM imaging confirmed cooperative binding and dual-DNA interaction. Electrophoretic mobility shift assay, AFM imaging, competition binding experiments with purified heterodimer Journal of molecular biology High 11575920
2001 MLH1 overexpression inactivates MMR of replication errors without changing expression of other repair genes; the mutator effect requires MLH1-PMS1 interaction (disrupted by missense mutation) and is suppressed by co-overexpression of PMS1, confirming that functional stoichiometric imbalance between MLH1 and PMS1 underlies the dominant-negative effect. Yeast genetics, genome-wide expression microarray, analytical ultracentrifugation, epistasis analysis Molecular and cellular biology High 11154280
2002 Human MutLα (MLH1-PMS2) ATPase activity in both subunits is required for mismatch repair in vitro; Mlh1 binds ATP with higher affinity and undergoes a more pronounced ATP-induced conformational change than PMS2; single ATPase-dead mutants (E→A in conserved catalytic Glu) are partially defective, whereas the double mutant abolishes repair. In vitro MMR assay with purified mutant proteins expressed in insect cells; limited proteolysis to monitor conformational changes The Journal of biological chemistry High 11897781
2003 DNA binding by Mlh1 is mapped to its N-terminal domain (NTD); substitutions of conserved positively charged residues in the Mlh1 NTD reduce NTD DNA binding and cause a mutator phenotype in yeast, whereas equivalent substitutions in Pms1 have much smaller effects, indicating that Mlh1 plays the primary DNA-binding role in the heterodimer. In vitro DNA binding with purified NTD fragments; yeast mutator assay; mass spectrometry mapping Nucleic acids research High 12682353
2003 MLH1 missense mutations that mimic HNPCC germline variants differentially affect meiotic functions: DNA binding and ATP binding (but not ATP hydrolysis) are required for meiotic crossing over, whereas different mutations selectively impair meiotic heteroduplex repair, chromosome segregation, or gametogenesis, revealing separation of mitotic and meiotic MLH1 functions. Yeast genetics; 14 MLH1 missense mutations analyzed for meiotic crossover frequency, heteroduplex repair, chromosome segregation, and spore viability Genetics High 12618391
2003 MLH1 physically interacts with the c-MYC proto-oncogene; this interaction was demonstrated in vitro by yeast two-hybrid and GST-pulldown, and in vivo by co-immunoprecipitation from human tumor cell extracts; elevated c-MYC expression increases the frameshift mutation rate at HGPRT, consistent with partial MMR inhibition. Yeast two-hybrid, GST-fusion pulldown, co-immunoprecipitation from tumor cells, HGPRT mutation assay Oncogene Medium 12584560
2003 MLH1 is required for alkylation-induced apoptosis; in Mgmt−/−Mlh1−/− mouse cells, MNU-induced caspase-3 activation is abolished; even Mlh1 haploinsufficiency (Mlh1+/−) eliminates caspase-3 induction, indicating that the cellular MLH1 level is a critical determinant of whether alkylated cells undergo apoptosis versus mutagenesis. Gene-targeted mouse cell lines (Mgmt−/−, Mlh1−/−, compound); cell survival assay, caspase-3 induction, HGPRT mutation frequency DNA repair High 13679151
2007 MLH1 and ATM cooperate to activate c-Jun/JNK/MKK4 MAPK signaling via MEKK1 in response to the alkylating agent MNNG; the tyrosine kinase c-Abl is required for this cascade and forms a complex with MEKK1 and MLH1, positioning MLH1 as a component of a damage-activated signaling scaffold. Co-immunoprecipitation; kinase activity assays; siRNA/pharmacological inhibitor experiments; MLH1-deficient cell lines The Journal of biological chemistry Medium 17804421
2009 Human MLH1 contains a bipartite nuclear localization signal (NLS) and PMS2 contains a monopartite NLS; MLH1 and PMS2 can each independently enter the nucleus, but MutLα heterodimer is imported more efficiently; the bipartite NLS of MLH1 can direct nuclear import of the heterodimer even when PMS2's NLS is mutated, providing redundancy that ensures nuclear transport. Confocal microscopy of transfected constructs; MMR-deficient cell complementation; NLS deletion/mutation analysis Molecular carcinogenesis Medium 19148896
2009 Chromate (Cr[VI]) exposure induces G9a-mediated H3K9 dimethylation at the MLH1 gene promoter, which silences MLH1 mRNA expression; ascorbate supplementation partially reverses this H3K9 dimethylation and restores MLH1 expression. ChIP for histone methylation marks at MLH1 promoter; RT-PCR for MLH1 mRNA; pharmacological manipulation (ascorbate) Toxicology and applied pharmacology Medium 19376149
2010 An HNPCC-associated MLH1 mutation (L607H) abolishes MLH1 binding to the FANCJ/BACH1 DNA helicase; loss of this interaction delays MMR signaling and apoptotic response to O6-methylguanine lesions, creating time for MGMT to reverse methylation and conferring resistance; cells lacking FANCJ also show unique sensitivity to DNA cross-linking agents. Co-immunoprecipitation; MMR signaling assays; apoptosis assays in FANCJ-deficient cells; clinical mutation analysis Cancer prevention research Medium 20978114
2014 PCNA activates the Mlh1-Pms1 endonuclease in an Exo1-independent MMR pathway; PCNA mutations affecting Msh2-Msh6 binding or Mlh1-Pms1 endonuclease activation caused selective Exo1-independent MMR defects, and Msh2-Msh6 is required to localize PCNA to repair sites to activate the endonuclease. Genetic screen for PCNA mutants (pol30 alleles) in S. cerevisiae; biochemical analysis of PCNA-protein interactions; Mlh1-Pms1 endonuclease assay; live-cell focus analysis Molecular cell High 24981171
2017 ERβ binds estrogen response elements in the proximal MLH1 promoter and transcriptionally activates MLH1 expression in response to 17β-estradiol, enhancing MMR activity and microsatellite stability; ERα does not mediate this effect; ERβ-driven MLH1 induction suppresses CRC tumor growth in vitro and in vivo. Luciferase reporter assay; chromatin immunoprecipitation; overexpression/knockdown of ERα and ERβ; in vitro MMR assay; xenograft model Oncotarget Medium 28404976
2018 HDAC6 interacts with MLH1 and deacetylates it both in vitro and in vivo at four identified acetylation sites; deacetylation of MLH1 by HDAC6 blocks assembly of the MutSα-MutLα complex; the deacetylation-mimetic MLH1 mutant confers resistance to 6-thioguanine, whereas acetylation-mimetic MLH1 retains sensitivity. Co-immunoprecipitation; in vitro HDAC6 deacetylase assay; MS identification of acetylation sites; MMR complex assembly assay; 6-TG cytotoxicity assay The Journal of biological chemistry High 30770470
2018 CK2 phosphorylates MLH1 at serine 477, as confirmed by in vitro kinase assay; phospho-MLH1-S477 loses MMR activity in an in vitro MMR assay; levels of pMLH1-S477 vary during the cell cycle, suggesting CK2-mediated phosphorylation is a cell-cycle-regulated switch that turns off MMR. Mass spectrometry identification of phospho-S477; in vitro CK2 kinase assay; in vitro MMR assay with phospho-mimetic/null mutants; cell-cycle fractionation Molecular carcinogenesis High 30136313
2019 Disease-linked MLH1 missense variants are present at reduced cellular levels due to structural destabilization; destabilized MLH1 variants are targeted for chaperone-assisted proteasomal degradation, which also causes co-degradation of PMS1 and PMS2; computational thermodynamic stability predictions of MLH1 variants correlate with reduced steady-state levels and loss of function. Protein stability measurements; proteasome inhibitor treatment; in silico saturation mutagenesis; steady-state protein level quantification eLife Medium 31697235
2020 Loss of MLH1 (MutLα subunit) abolishes MutLα-specific regulation of exonuclease 1 (Exo1), causing unrestrained DNA excision that generates excess single-strand DNA, RPA exhaustion, DNA breaks, and cytoplasmic DNA release, which activates the cGAS-STING pathway; this mechanism explains innate immune activation in MMR-deficient tumors. MLH1 knockout/knockdown cell lines; ssDNA and RPA exhaustion assays; cytoplasmic DNA detection; cGAS-STING activation assays; Exo1 activity assays Cancer cell High 33338427
2020 Human MutLγ (MLH1-MLH3 heterodimer) is an endonuclease that nicks DNA; MLH1-MLH3 incision of covalently closed loop-containing DNA is promoted by MutSβ (MSH2-MSH3) and targeted to the strand opposite the loop; the resulting strand break initiates downstream events leading to triplet repeat DNA expansion in human cell extracts. In vitro endonuclease assay with purified human MutLγ; loop substrate cleavage assay; strand-specificity mapping; human cell extract expansion assay Proceedings of the National Academy of Sciences of the United States of America High 32015124
2020 Human MSH4-MSH5 (MutSγ) binds branched recombination intermediates and recruits MutLγ (MLH1-MLH3), stabilizing the ensemble; MutSγ directly stimulates MutLγ endonuclease activity; EXO1 further stimulates MutLγ only in the presence of MutSγ; RFC and PCNA are additional components; PCNA interaction with MutLγ is required for meiotic crossover formation; MutLγ-MutSγ-EXO1-RFC-PCNA preferentially nicks dsDNA adjacent to Holliday junctions rather than resolving them. Biochemical reconstitution; endonuclease assays with purified components; S. cerevisiae genetics (PCNA-interaction mutants); DNA substrate binding assays Nature High 32814904
2021 FAN1 binds MLH1 via a conserved N-terminal SPYF motif; this interaction restricts MLH1 recruitment by MSH3, thereby inhibiting assembly of a functional MMR complex that would otherwise promote CAG repeat expansion; separately, FAN1 nuclease activity promotes accurate repair. Co-immunoprecipitation; SPYF motif identification and mutagenesis; CAG repeat expansion assays in cells; MLH1-FAN1 interaction domain mapping Cell reports Medium 34469738
2022 Mlh1 contains a conserved linker motif (S. cerevisiae residues 391–415) required for MMR and endonuclease activity; Mlh1-R401A,D403A-Pms1 is defective in MMR and endonuclease activity in vitro despite the motif being >750 Å from known active sites; peptides encoding this motif inhibit wild-type Mlh1-Pms1 endonuclease; the motif can function at ectopic positions within the linker and within Pms1, and human cancer mutations in the equivalent region cause loss of function. In vitro MMR assay; endonuclease assay with purified mutant proteins; peptide inhibition experiment; yeast genetic assay; structural distance mapping Proceedings of the National Academy of Sciences of the United States of America High 36215471
2022 Mlh1 is recruited to mispaired DNA by Msh2-Msh6 through interactions with both the Msh2 connector domain and the Msh6 ATPase/core domain; MLH1 mutations affecting both interfaces cause MMR defects and loss of recruitment to mispairs in reconstituted reactions, while equivalent Pms1 mutations do not, establishing MLH1 as the Msh2-Msh6-interacting subunit of MutLα. In vitro reconstituted MMR assay; pulldown/binding assays with purified proteins; yeast genetic epistasis; domain-mapping mutagenesis DNA repair High 36122480
2024 Mutant huntingtin (mHTT) displays greatly reduced interaction with MutLα (MLH1-PMS2) compared with wild-type HTT; normal HTT stabilizes MLH1 protein through its interaction with MutLα; loss of this stabilizing interaction in HD cells causes rapid MLH1 degradation, hyperactive Exo1-mediated DNA excision, cytoplasmic DNA accumulation, and cGAS-STING-dependent apoptosis. Co-immunoprecipitation of HTT/mHTT with MLH1; MLH1 protein stability assays; Exo1 DNA excision assay; cGAS-STING activation assays; HD cell models Proceedings of the National Academy of Sciences of the United States of America Medium 38498709
2024 SIRT2 deacetylates MLH1 at Lys402/443/461, thereby preventing MLH1 ubiquitination and degradation; SIRT2 inhibition or knockdown reduces MLH1 levels, increases DNA damage, and activates the cGAS-STING pathway; this was demonstrated by in vitro deacetylase assay and co-immunoprecipitation showing SIRT2-MLH1 interaction. Mass spectrometry-based proteomic profiling; co-immunoprecipitation; in vitro deacetylase assay; ubiquitination assay; cGAS-STING activation assay; genetic knockdown Science translational medicine Medium 40668890
2025 A de novo AI-designed small protein (MLH1-SB) binds to the MLH1-PMS2 dimeric interface and inhibits MutLα assembly; incorporation into prime editing architectures (PE7-SB2) suppresses MMR and improves prime editing efficiency 18.8-fold over PEmax in HeLa cells, validating the MLH1-PMS2 dimerization interface as a druggable target. Computational protein design (RFdiffusion/AlphaFold3); binding assay; prime editing efficiency measurement in HeLa cells and in mice Cell Medium 40769155
2018 A -35 kb enhancer element bound by CTCF regulates MLH1 expression in colorectal cells; CRISPR-Cas9 deletion of the CTCF-binding core within this enhancer reduces endogenous MLH1 expression; a germline SNP (rs143969848, G>A) within the CTCF-binding motif disrupts enhancer activity in colorectal carcinoma cells. Chromosome conformation capture (3C); luciferase reporter assay; chromatin immunoprecipitation; CRISPR-Cas9 endogenous deletion Clinical cancer research Medium 29898989
2017 MLH1 is required for activation of the G2/M cell cycle checkpoint in response to Cr(VI) exposure and limits Cr-induced mutagenesis; Cr(IV) (the ultimate mutagenic intermediate) induces DNA damage that requires functional MLH1 for checkpoint activation. MLH1-deficient and proficient cell lines; G2/M checkpoint assay; mutation frequency measurement at HPRT; chromium intermediate treatment Oncotarget Medium 29137397

Source papers

Stage 0 corpus · 100 papers · ranked by NIH iCite citations
Year Title Journal Citations PMID
2011 Cancer risks associated with germline mutations in MLH1, MSH2, and MSH6 genes in Lynch syndrome. JAMA 843 21642682
1996 Involvement of mouse Mlh1 in DNA mismatch repair and meiotic crossing over. Nature genetics 709 8673133
1994 MLH1, PMS1, and MSH2 interactions during the initiation of DNA mismatch repair in yeast. Science (New York, N.Y.) 292 8066446
1999 Human MLH1 deficiency predisposes to hematological malignancy and neurofibromatosis type 1. Cancer research 204 9927033
2020 MLH1 Deficiency-Triggered DNA Hyperexcision by Exonuclease 1 Activates the cGAS-STING Pathway. Cancer cell 202 33338427
2013 Cancer risks for MLH1 and MSH2 mutation carriers. Human mutation 196 23255516
1999 Mutator phenotypes conferred by MLH1 overexpression and by heterozygosity for mlh1 mutations. Molecular and cellular biology 165 10082584
2006 Prediction of MLH1 and MSH2 mutations in Lynch syndrome. JAMA 137 17003395
2024 Histone H3K9 Lactylation Confers Temozolomide Resistance in Glioblastoma via LUC7L2-Mediated MLH1 Intron Retention. Advanced science (Weinheim, Baden-Wurttemberg, Germany) 133 38477507
2020 Regulation of the MLH1-MLH3 endonuclease in meiosis. Nature 121 32814904
2020 Clinicopathological significance of deficient DNA mismatch repair and MLH1 promoter methylation in endometrioid endometrial carcinoma. Modern pathology : an official journal of the United States and Canadian Academy of Pathology, Inc 110 32060377
2009 Modulation of histone methylation and MLH1 gene silencing by hexavalent chromium. Toxicology and applied pharmacology 108 19376149
2014 PCNA and Msh2-Msh6 activate an Mlh1-Pms1 endonuclease pathway required for Exo1-independent mismatch repair. Molecular cell 89 24981171
2017 A modifier of Huntington's disease onset at the MLH1 locus. Human molecular genetics 87 28934397
2001 Microsatellite instability, MLH-1 promoter hypermethylation, and frameshift mutations at coding mononucleotide repeat microsatellites in ovarian tumors. Cancer 87 11753956
2003 Altered expression of MLH1, MSH2, and MSH6 in predisposition to hereditary nonpolyposis colorectal cancer. Journal of clinical oncology : official journal of the American Society of Clinical Oncology 85 14512394
2001 High affinity cooperative DNA binding by the yeast Mlh1-Pms1 heterodimer. Journal of molecular biology 80 11575920
2003 Microsatellite instability and expression of MLH1 and MSH2 in carcinomas of the small intestine. Cancer 79 12627520
2005 Conversion analysis for mutation detection in MLH1 and MSH2 in patients with colorectal cancer. JAMA 76 15713769
2005 Aberrant splicing in MLH1 and MSH2 due to exonic and intronic variants. Human genetics 75 16341550
2020 Human MutLγ, the MLH1-MLH3 heterodimer, is an endonuclease that promotes DNA expansion. Proceedings of the National Academy of Sciences of the United States of America 69 32015124
2011 Biallelic MLH1 SNP cDNA expression or constitutional promoter methylation can hide genomic rearrangements causing Lynch syndrome. Journal of medical genetics 69 21712435
2014 Predictive value of CHFR and MLH1 methylation in human gastric cancer. Gastric cancer : official journal of the International Gastric Cancer Association and the Japanese Gastric Cancer Association 66 24748501
2013 Reduction of MLH1 and PMS2 confers temozolomide resistance and is associated with recurrence of glioblastoma. Oncotarget 62 24259277
2002 Microsatellite instability and immunostaining for MSH-2 and MLH-1 in cutaneous and internal tumors from patients with the Muir-Torre syndrome. Journal of cutaneous pathology 59 12139636
2013 MLH1-silenced and non-silenced subgroups of hypermutated colorectal carcinomas have distinct mutational landscapes. The Journal of pathology 58 22899370
2008 Coexisting somatic promoter hypermethylation and pathogenic MLH1 germline mutation in Lynch syndrome. The Journal of pathology 58 17973250
2021 FAN1 controls mismatch repair complex assembly via MLH1 retention to stabilize CAG repeat expansion in Huntington's disease. Cell reports 56 34469738
2009 Classifying MLH1 and MSH2 variants using bioinformatic prediction, splicing assays, segregation, and tumor characteristics. Human mutation 56 19267393
2002 Contribution of human mlh1 and pms2 ATPase activities to DNA mismatch repair. The Journal of biological chemistry 55 11897781
1998 Characterization of MLH1 and MSH2 alternative splicing and its relevance to molecular testing of colorectal cancer susceptibility. Human genetics 55 9490293
2019 Computational and cellular studies reveal structural destabilization and degradation of MLH1 variants in Lynch syndrome. eLife 49 31697235
2003 DNA binding by yeast Mlh1 and Pms1: implications for DNA mismatch repair. Nucleic acids research 49 12682353
2001 Inactivation of DNA mismatch repair by increased expression of yeast MLH1. Molecular and cellular biology 49 11154280
2007 Microsatellite instability and MLH1 promoter hypermethylation in colorectal cancer. World journal of gastroenterology 48 17465465
2004 HNPCC mutation MLH1 P648S makes the functional protein unstable, and homozygosity predisposes to mild neurofibromatosis type 1. Genes, chromosomes & cancer 45 15139004
2015 Relationship between MLH-1, MSH-2, PMS-2,MSH-6 expression and clinicopathological features in colorectal cancer. International journal of clinical and experimental pathology 44 26097592
2002 Mutation analysis of MLH1 and MSH2 genes performed by denaturing high-performance liquid chromatography. Journal of biochemical and biophysical methods 44 11879922
2003 MLH1 mutations differentially affect meiotic functions in Saccharomyces cerevisiae. Genetics 39 12618391
2003 Roles of MGMT and MLH1 proteins in alkylation-induced apoptosis and mutagenesis. DNA repair 39 13679151
2003 Alterations in PMS2, MSH2 and MLH1 expression in human prostate cancer. International journal of oncology 38 12684669
2019 MLH1 deficiency leads to deregulated mitochondrial metabolism. Cell death & disease 36 31641109
2019 HDAC6 regulates DNA damage response via deacetylating MLH1. The Journal of biological chemistry 35 30770470
2017 Expression and promoter DNA methylation of MLH1 in colorectal cancer and lung cancer. Pathology, research and practice 34 28214209
2002 DNA binding properties of the yeast Msh2-Msh6 and Mlh1-Pms1 heterodimers. Biological chemistry 34 12222686
2013 MGMT and MLH1 methylation in Helicobacter pylori-infected children and adults. World journal of gastroenterology 33 23716983
2012 Comprehensive functional assessment of MLH1 variants of unknown significance. Human mutation 32 22736432
2020 MLH1 Deficiency Induces Cetuximab Resistance in Colon Cancer via Her-2/PI3K/AKT Signaling. Advanced science (Weinheim, Baden-Wurttemberg, Germany) 30 32670759
2003 Expression of Fhit, Mlh1, and P53 protein in human gallbladder carcinoma. Cancer letters 30 12969785
2007 MLH1- and ATM-dependent MAPK signaling is activated through c-Abl in response to the alkylator N-methyl-N'-nitro-N'-nitrosoguanidine. The Journal of biological chemistry 29 17804421
2007 Polymorphic MLH1 and risk of cancer after methylating chemotherapy for Hodgkin lymphoma. Journal of medical genetics 29 17959715
2003 Interactions of the DNA mismatch repair proteins MLH1 and MSH2 with c-MYC and MAX. Oncogene 29 12584560
2012 Vitamin and antioxidant rich diet increases MLH1 promoter DNA methylation in DMT2 subjects. Clinical epigenetics 28 23025454
2023 Constitutional MLH1 Methylation Is a Major Contributor to Mismatch Repair-Deficient, MLH1-Methylated Colorectal Cancer in Patients Aged 55 Years and Younger. Journal of the National Comprehensive Cancer Network : JNCCN 27 37433431
2018 Lynch syndrome-associated endometrial carcinoma with MLH1 germline mutation and MLH1 promoter hypermethylation: a case report and literature review. BMC cancer 27 29783979
2009 Deficiencies in Chfr and Mlh1 synergistically enhance tumor susceptibility in mice. The Journal of clinical investigation 27 19690386
2019 Chromate exposure induces DNA hypermethylation of the mismatch repair gene MLH1 in lung cancer. Molecular carcinogenesis 26 31579968
2014 MLH1 constitutional and somatic methylation in patients with MLH1 negative tumors fulfilling the revised Bethesda criteria. Epigenetics 26 25437057
2019 Downregulation of SPTAN1 is related to MLH1 deficiency and metastasis in colorectal cancer. PloS one 25 30856214
2016 Finding the needle in a haystack: identification of cases of Lynch syndrome with MLH1 epimutation. Familial cancer 25 26886015
2023 Differential outcomes and immune checkpoint inhibitor response among endometrial cancer patients with MLH1 hypermethylation versus MLH1 "Lynch-like" mismatch repair gene mutation. Gynecologic oncology 24 37683549
2012 MLH1 and XRCC1 polymorphisms in Mexican patients with colorectal cancer. Genetics and molecular research : GMR 24 22843073
2002 Polymorphisms and HNPCC: PMS2-MLH1 protein interactions diminished by single nucleotide polymorphisms. Human mutation 24 11793469
2023 MLH1 Promoter Methylation Could Be the Second Hit in Lynch Syndrome Carcinogenesis. Genes 23 38003003
2023 MLH1 Promotor Hypermethylation in Colorectal and Endometrial Carcinomas from Patients with Lynch Syndrome. The Journal of molecular diagnostics : JMD 23 38061582
2018 Expressional analysis of MLH1 and MSH2 in breast cancer. Current problems in cancer 23 30149959
2010 Assessing the link between BACH1/FANCJ and MLH1 in DNA crosslink repair. Environmental and molecular mutagenesis 23 20658644
2014 Expression of DNA mismatch repair proteins MLH1, MSH2, and MSH6 in recurrent glioblastoma. Neurological research 22 24995467
2013 Correlation of MLH1 and MGMT expression and promoter methylation with genomic instability in patients with thyroid carcinoma. BMC cancer 22 23414134
2010 An MLH1 mutation links BACH1/FANCJ to colon cancer, signaling, and insight toward directed therapy. Cancer prevention research (Philadelphia, Pa.) 22 20978114
2009 Nuclear import of human MLH1, PMS2, and MutLalpha: redundancy is the key. Molecular carcinogenesis 22 19148896
2019 Clinical significance of MLH1/MSH2 for stage II/III sporadic colorectal cancer. World journal of gastrointestinal oncology 21 31798786
2018 Mlh1 deficiency in normal mouse colon mucosa associates with chromosomally unstable colon cancer. Carcinogenesis 20 29701748
2015 Ionizing radiation, inflammation, and their interactions in colon carcinogenesis in Mlh1-deficient mice. Cancer science 20 25529563
2009 MLH1 expression sensitises ovarian cancer cells to cell death mediated by XIAP inhibition. British journal of cancer 19 19603033
2024 Mutant huntingtin protein induces MLH1 degradation, DNA hyperexcision, and cGAS-STING-dependent apoptosis. Proceedings of the National Academy of Sciences of the United States of America 18 38498709
2014 Association of DCC, MLH1, GSTT1, GSTM1, and TP53 gene polymorphisms with colorectal cancer in Kazakhstan. Tumour biology : the journal of the International Society for Oncodevelopmental Biology and Medicine 18 25249451
2003 Mlh1 deficiency accelerates myeloid leukemogenesis in neurofibromatosis 1 (Nf1) heterozygous mice. Oncogene 18 12881715
2025 AI-generated MLH1 small binder improves prime editing efficiency. Cell 17 40769155
2011 An intronic mutation in MLH1 associated with familial colon and breast cancer. Familial cancer 17 20717847
2021 Tissue-specific reduction in MLH1 expression induces microsatellite instability in intestine of Mlh1+/- mice. DNA repair 16 34311271
2014 DNA mismatch repair gene MLH1 induces apoptosis in prostate cancer cells. Oncotarget 16 25526032
2005 Methylation of the MLH1 gene in hematological malignancies. Oncology reports 16 15944788
2023 Identifying primary and secondary MLH1 epimutation carriers displaying low-level constitutional MLH1 methylation using droplet digital PCR and genome-wide DNA methylation profiling of colorectal cancers. Clinical epigenetics 15 37270516
2022 Gene fusions and oncogenic mutations in MLH1 deficient and BRAFV600E wild-type colorectal cancers. Virchows Archiv : an international journal of pathology 15 35237889
2022 Genomic landscape of pathogenic mutation of APC, KRAS, TP53, PIK3CA, and MLH1 in Indonesian colorectal cancer. PloS one 15 35709138
2022 The unstructured linker of Mlh1 contains a motif required for endonuclease function which is mutated in cancers. Proceedings of the National Academy of Sciences of the United States of America 14 36215471
2017 Loss of MLH1 sensitizes colon cancer cells to DNA-PKcs inhibitor KU60648. Molecular carcinogenesis 14 28224663
2017 DNA mismatch repair protein Mlh1 is required for tetravalent chromium intermediate-induced DNA damage. Oncotarget 14 29137397
2011 An American founder mutation in MLH1. International journal of cancer 14 21671475
2019 The expression of MLH1 and MSH2 genes among inhabitants of high background radiation area of Ramsar, Iran. Journal of environmental radioactivity 13 31323602
2018 Evaluation of MLH1 variants of unclear significance. Genes, chromosomes & cancer 13 29520894
2018 Disruption of a -35 kb Enhancer Impairs CTCF Binding and MLH1 Expression in Colorectal Cells. Clinical cancer research : an official journal of the American Association for Cancer Research 13 29898989
2018 DNA mismatch repair activity of MutLα is regulated by CK2-dependent phosphorylation of MLH1 (S477). Molecular carcinogenesis 13 30136313
2017 Estrogen enhances mismatch repair by induction of MLH1 expression via estrogen receptor-β. Oncotarget 13 28404976
2014 Expression of MLH1 and MSH2 in urothelial carcinoma of the renal pelvis. Tumour biology : the journal of the International Society for Oncodevelopmental Biology and Medicine 13 24874052
2008 Evaluation of the MLH1 I219V alteration in DNA mismatch repair activity and ulcerative colitis. Inflammatory bowel diseases 13 18200512
2025 Targeting SIRT2 induces MLH1 deficiency and boosts antitumor immunity in preclinical colorectal cancer models. Science translational medicine 12 40668890
2022 Mlh1 interacts with both Msh2 and Msh6 for recruitment during mismatch repair. DNA repair 12 36122480
2010 MLH1 Differential allelic expression in mutation carriers and controls. Annals of human genetics 12 20860725

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