Biochemical Analysis of the Human Mismatch Repair Proteins hMutSα MSH2G674A-MSH6 and MSH2-MSH6T1219D

Geng, Hui; Sakato, Miho; DeRocco, Vanessa; Yamane, Kunio; Du, Chunwei; Erie, Dorothy A.; Hingorani, Manju; Hsieh, Peggy

doi:10.1074/jbc.m111.316919

Cited by 30 publications

(40 citation statements)

References 54 publications

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“…A mutant human MutSα protein harboring the equivalent MSH6T1219D substitution fails to interact with MutLα and does not support any detectable excision in an in vitro MMR assay suggesting that a DDR can occur in cells in the absence of excision [92]. The uncoupling of MMR and apoptotic signaling is consistent with a direct signaling model though a subsequent study suggests an alternative explanation.…”

Section: Dna Methylation and The Ddrmentioning

confidence: 95%

DNA mismatch repair and the DNA damage response

2016

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This review discusses the role of DNA mismatch repair (MMR) in the DNA damage response (DDR) that triggers cell cycle arrest and, in some cases, apoptosis. Although the focus is on findings from mammalian cells, much has been learned from studies in other organisms including bacteria and yeast [1,2]. MMR promotes a DDR mediated by a key signaling kinase, ATM and Rad3-related (ATR), in response to various types of DNA damage including some encountered in widely used chemotherapy regimes. An introduction to the DDR mediated by ATR reveals its immense complexity and highlights the many biological and mechanistic questions that remain. Recent findings and future directions are highlighted.

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Section: Dna Methylation and The Ddrmentioning

confidence: 95%

DNA mismatch repair and the DNA damage response

2016

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“…Human MLH1-PMS2 was a gift from Peggy Hsieh’s laboratory and was purified as previously described [67,68]. Yeast Mlh1-Pms1, Msh2-Msh3, RFC, and PCNA were purified from yeast as described previously [69–72].…”

Section: Methodsmentioning

confidence: 99%

The mismatch repair and meiotic recombination endonuclease Mlh1-Mlh3 is activated by polymer formation and can cleave DNA substrates in trans

et al. 2017

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Crossing over between homologs is initiated in meiotic prophase by the formation of DNA double-strand breaks that occur throughout the genome. In the major interference-responsive crossover pathway in baker’s yeast, these breaks are resected to form 3' single-strand tails that participate in a homology search, ultimately forming double Holliday junctions (dHJs) that primarily include both homologs. These dHJs are resolved by endonuclease activity to form exclusively crossovers, which are critical for proper homolog segregation in Meiosis I. Recent genetic, biochemical, and molecular studies in yeast are consistent with the hypothesis of Mlh1-Mlh3 DNA mismatch repair complex acting as the major endonuclease activity that resolves dHJs into crossovers. However, the mechanism by which the Mlh1-Mlh3 endonuclease is activated is unknown. Here, we provide evidence that Mlh1-Mlh3 does not behave like a structure-specific endonuclease but forms polymers required to generate nicks in DNA. This conclusion is supported by DNA binding studies performed with different-sized substrates that contain or lack polymerization barriers and endonuclease assays performed with varying ratios of endonuclease-deficient and endonuclease-proficient Mlh1-Mlh3. In addition, Mlh1-Mlh3 can generate religatable double-strand breaks and form an active nucleoprotein complex that can nick DNA substrates in trans. Together these observations argue that Mlh1-Mlh3 may not act like a canonical, RuvC-like Holliday junction resolvase and support a novel model in which Mlh1-Mlh3 is loaded onto DNA to form an activated polymer that cleaves DNA.

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“…The other MutS subunit also hydrolyzes ATP, but at a much slower rate (~30-fold) that is indistinguishable from k cat , suggesting that this event may limit catalytic turnover [40]. Finally, ADP release from at least one of the MutS subunits is slow and likely helps limit the turnover rate as well [47,48]; Mg 2+ influences ADP release, but the effects are not completely resolved since it appears to stabilize ADP in human MutSα and destabilize it in E. coli MutS [44,49]. …”

Section: Muts Actions In Mmrmentioning

confidence: 99%

“…3b) [23]. Notably, ADP release occurs 10 – 30-fold faster from the MutS-mismatch complex than from free MutS [47,48]; thus, mismatched DNA works as a nucleotide exchange factor to trigger ADP release and favor ATP binding [44,49]. This ADP-ATP exchange is at the heart of the molecular switch model for MutS function in MMR [47].…”

Section: Muts Actions In Mmrmentioning

confidence: 99%

Mismatch binding, ADP–ATP exchange and intramolecular signaling during mismatch repair

Hingorani

2016

DNA Repair

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The focus of this article is on the DNA binding and ATPase activities of the mismatch repair (MMR) protein, MutS—our current understanding of how this protein uses ATP to fuel its actions on DNA and initiate repair via interactions with MutL, the next protein in the pathway. Structure-function and kinetic studies have yielded detailed views of the MutS mechanism of action in MMR. How MutS and MutL work together after mismatch recognition to enable strand-specific nicking, which leads to strand excision and synthesis, is less clear and remains an active area of investigation.

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Biochemical Analysis of the Human Mismatch Repair Proteins hMutSα MSH2G674A-MSH6 and MSH2-MSH6T1219D

Cited by 30 publications

References 54 publications

DNA mismatch repair and the DNA damage response

DNA mismatch repair and the DNA damage response

The mismatch repair and meiotic recombination endonuclease Mlh1-Mlh3 is activated by polymer formation and can cleave DNA substrates in trans

Mismatch binding, ADP–ATP exchange and intramolecular signaling during mismatch repair

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