Conservation of functional asymmetry in the mammalian MutLα ATPase

Jennifer R. Johnson, Naz Erdeniz, Megan Nguyen, Sandra Dudley, Robert (Mike) Liskay

Research output: Contribution to journalArticle

6 Citations (Scopus)

Abstract

The DNA mismatch repair (MMR) protein dimer MutLα is comprised of the MutL homologues MLH1 and PMS2, which each belong to the family of GHL ATPases. These ATPases undergo functionally important conformational changes, including dimerization of the NH2-termini associated with ATP binding and hydrolysis. Previous studies in yeast and biochemical studies with the mammalian proteins established the importance of the MutLα ATPase for overall MMR function. Additionally, the studies in yeast demonstrated a functional asymmetry between the contributions of the Mlh1 and Pms1 ATPase domains to MMR that was not reflected in the biochemical studies. We investigated the effect of mutating the highly conserved ATP hydrolysis and Mg2+ binding residues of MLH1 and PMS2 in mammalian cell lines. Amino acid substitutions in MLH1 intended to impact either ATP binding or hydrolysis disabled MMR, as measured by instability at microsatellite sequences, to an extent similar to MLH1-null mutation. Furthermore, cells expressing these MLH1 mutations exhibited resistance to the MMR-dependent cytotoxic effect of 6-thioguanine (6-TG). In contrast, ATP hydrolysis and binding mutants of PMS2 displayed no measurable increase in microsatellite instability or resistance to 6-TG. Our findings suggest that, in vivo, the integrity of the MLH1 ATPase domain is more critical than the PMS2 ATPase domain for normal MMR functions. These in vivo results are in contrast to results obtained previously in vitro that showed no functional asymmetry within the MutLα ATPase, highlighting the differences between in vivo and in vitro systems.

Original languageEnglish (US)
Pages (from-to)1209-1213
Number of pages5
JournalDNA Repair
Volume9
Issue number11
DOIs
StatePublished - Nov 10 2010

Fingerprint

DNA Mismatch Repair
Adenosine Triphosphatases
Conservation
Repair
Hydrolysis
Adenosine Triphosphate
Thioguanine
Microsatellite Instability
Microsatellite Repeats
Yeast
Yeasts
Cells
Mutation
Dimerization
Amino Acid Substitution
Dimers
Proteins
Substitution reactions
Amino Acids
Cell Line

Keywords

  • ATPase
  • DNA methylation damage response
  • Mismatch repair
  • MutLα

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology

Cite this

Johnson, J. R., Erdeniz, N., Nguyen, M., Dudley, S., & Liskay, R. M. (2010). Conservation of functional asymmetry in the mammalian MutLα ATPase. DNA Repair, 9(11), 1209-1213. https://doi.org/10.1016/j.dnarep.2010.08.006

Conservation of functional asymmetry in the mammalian MutLα ATPase. / Johnson, Jennifer R.; Erdeniz, Naz; Nguyen, Megan; Dudley, Sandra; Liskay, Robert (Mike).

In: DNA Repair, Vol. 9, No. 11, 10.11.2010, p. 1209-1213.

Research output: Contribution to journalArticle

Johnson, JR, Erdeniz, N, Nguyen, M, Dudley, S & Liskay, RM 2010, 'Conservation of functional asymmetry in the mammalian MutLα ATPase', DNA Repair, vol. 9, no. 11, pp. 1209-1213. https://doi.org/10.1016/j.dnarep.2010.08.006
Johnson JR, Erdeniz N, Nguyen M, Dudley S, Liskay RM. Conservation of functional asymmetry in the mammalian MutLα ATPase. DNA Repair. 2010 Nov 10;9(11):1209-1213. https://doi.org/10.1016/j.dnarep.2010.08.006
Johnson, Jennifer R. ; Erdeniz, Naz ; Nguyen, Megan ; Dudley, Sandra ; Liskay, Robert (Mike). / Conservation of functional asymmetry in the mammalian MutLα ATPase. In: DNA Repair. 2010 ; Vol. 9, No. 11. pp. 1209-1213.
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