Background: DNA mismatch repair proteins participate in diverse cellular functions including DNA damage response and repair. As a member of this protein family, the molecular mechanisms of hMSH4 in mitotic cells are poorly defined. It is known that hMSH4 is promiscuous, and among various interactions the hMSH4-hMSH5 interaction is involved in recognizing DNA intermediate structures arising from homologous recombination (HR).
Results: We identified a new hMSH4 interacting protein eIF3f--a protein that functions not only in translation but also in the regulation of apoptosis and tumorigenesis in humans. Our studies have demonstrated that hMSH4-eIF3f interaction is mediated through the N-terminal regions of both proteins. The interaction with eIF3f fosters hMSH4 protein stabilization, which in turn sustains γ-H2AX foci and compromises cell survival in response to ionizing radiation (IR)-induced DNA damage. These effects can be, at least partially, attributed to the down-regulation of NHEJ activity by hMSH4. Furthermore, the interplay between hMSH4 and eIF3f inhibits IR-induced AKT activation, and hMSH4 promotes eIF3f-mediated bypass of S phase arrest, and ultimately enhancing an early G2/M arrest in response to IR treatment.
Conclusion: Our current study has revealed a role for hMSH4 in the maintenance of genomic stability by suppressing NHEJ-mediated DSB repair.
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http://dx.doi.org/10.1186/1476-4598-12-51 | DOI Listing |
Int J Mol Sci
October 2013
School of Molecular Biosciences, Mail Drop 64-7520, Washington State University, Pullman, WA 99164-7520, USA.
Acetylation of non-histone proteins is increasingly recognized as an important post-translational modification for controlling the actions of various cellular processes including DNA repair and damage response. Here, we report that the human MutS homologue hMSH4 undergoes acetylation following DNA damage induced by ionizing radiation (IR). To determine which acetyltransferases are responsible for hMSH4 acetylation in response to DNA damage, potential interactions of hMSH4 with hTip60, hGCN5, and hMof were analyzed.
View Article and Find Full Text PDFCurr Genomics
April 2013
STARS Program, College of Veterinary Medicine, Washington State University, Pullman, WA 99164-7520, USA ; School of Molecular Biosciences, College of Veterinary Medicine, Washington State University, Pullman, WA 99164-7520, USA.
The prominence of the human mismatch repair (MMR) pathway is clearly reflected by the causal link between MMR gene mutations and the occurrence of Lynch syndrome (or HNPCC). The MMR family of proteins also carries out a plethora of diverse cellular functions beyond its primary role in MMR and homologous recombination. In fact, members of the MMR family of proteins are being increasingly recognized as critical mediators between DNA damage repair and cell survival.
View Article and Find Full Text PDFFASEB J
December 2013
1School of Molecular Biosciences, Mail Drop 64-7520, College of Veterinary Medicine, Washington State University, Pullman, WA 99164-7520, USA.
Ubiquitination is an important mechanism for the regulation of diverse cellular functions, including proteolysis and DNA repair. The human MutS family protein hMSH4 functions in meiotic recombinational DNA double-strand break (DSB) repair. It was previously observed that hMSH4 interacts with the von Hippel-Lindau binding protein 1 (VBP1), a partner of the VHL ubiquitin E3 ligase as well as a subunit of the prefoldin complex.
View Article and Find Full Text PDFMol Cancer
June 2013
School of Molecular Biosciences, College of Veterinary Medicine, Washington State University, Mail Drop 64-7520, Pullman, WA 99164, USA.
Background: DNA mismatch repair proteins participate in diverse cellular functions including DNA damage response and repair. As a member of this protein family, the molecular mechanisms of hMSH4 in mitotic cells are poorly defined. It is known that hMSH4 is promiscuous, and among various interactions the hMSH4-hMSH5 interaction is involved in recognizing DNA intermediate structures arising from homologous recombination (HR).
View Article and Find Full Text PDFNucleic Acids Res
June 2010
FRE 3086 Instabilité génétique: Maladies rares et cancers, Université de Nice Sophia-Antipolis, CNRS, Nice Cedex 2, France.
MSH5 is a MutS-homologous protein required for meiotic DNA recombination. In addition, recent studies suggest that the human MSH5 protein (hMSH5) participates to mitotic recombination and to the cellular response to DNA damage and thus raise the possibility that a tight control of hMSH5 function(s) may be important for genomic stability. With the aim to characterize mechanisms potentially involved in the regulation of hMSH5 activity, we investigated its intracellular trafficking properties.
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