Cadmium inhibits mismatch repair by blocking the ATPase activity of the MSH2-MSH6 complex.
Cadmium (Cd2+) is a known carcinogen that inactivates the DNA mismatch repair (MMR) pathway. In this study, we have tested the effect of Cd2+ exposure on the enzymatic activity of the mismatch binding complex MSH2-MSH6. Our results indicate that Cd2+ is highly inhibitory to the ATP binding and hydrolysis activities of MSH2-MSH6, and less inhibitory to its DNA mismatch binding activity. The inhibition of the ATPase activity appears to be dose and exposure time dependent. However, the inhibition of the ATPase activity by Cd2+ is prevented by cysteine and histidine, suggesting that these residues are essential for the ATPase activity and are targeted by Cd2+. A comparison of the mechanism of inhibition with N-ethyl maleimide, a sulfhydryl group inhibitor, indicates that this inhibition does not occur through direct inactivation of sulfhydryl groups. Zinc (Zn2+) does not overcome the direct inhibitory effect of Cd2+ on the MSH2-MSH6 ATPase activity in vitro. However, the increase in the mutator phenotype of yeast cells exposed to Cd2+ was prevented by excess Zn2+, probably by blocking the entry of Cd2+ into the cell. We conclude that the inhibition of MMR by Cd2+ is through the inactivation of the ATPase activity of the MSH2-MSH6 heterodimer, resulting in a dominant negative effect and causing a mutator phenotype.
Banerjee
Sreeparna
S
Institute of Molecular Medicine and Genetics, Medical College of Georgia 1120 15th Street, Augusta, GA 30912, USA.
Flores-Rozas
Hernan
H
D000251:Adenosine Triphosphatases / Q000037:antagonists & inhibitors*; D000255:Adenosine Triphosphate / Q000378:metabolism; D000596:Amino Acids / Q000494:pharmacology; D020137:Base Pair Mismatch; D002104:Cadmium / Q000494:pharmacology*; D004247:DNA / Q000378:metabolism; D004260:DNA Repair / Q000187:drug effects*; D004268:DNA-Binding Proteins / Q000037:antagonists & inhibitors* / Q000737:chemistry; D005033:Ethylmaleimide / Q000494:pharmacology; D051718:MutS Homolog 2 Protein; D009154:Mutation; D010641:Phenotype; D029701:Saccharomyces cerevisiae Proteins / Q000037:antagonists & inhibitors* / Q000737:chemistry; D013439:Sulfhydryl Reagents / Q000494:pharmacology; D015003:Yeasts / Q000166:cytology / Q000235:genetics; D015032:Zinc / Q000494:pharmacology
D000596:Amino Acids; D004268:DNA-Binding Proteins; C098790:MSH6 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D013439:Sulfhydryl Reagents; D002104:Cadmium; D000255:Adenosine Triphosphate; D004247:DNA; D000251:Adenosine Triphosphatases; C489751:MSH2 protein, S cerevisiae; D051718:MutS Homolog 2 Protein; D015032:Zinc; D005033:Ethylmaleimide
DNA Repair (Amst). 2002 Sep 4;1(9):743-53
12509278
J Biol Chem. 2003 May 16;278(20):18557-62
12624105
J Nutr. 2003 May;133(5 Suppl 1):1532S-5S
12730459
J Biol Chem. 2000 Nov 24;275(47):36550-5
10938287
Environ Health Perspect. 2004 May;112(7):799-804
15159209
Biochim Biophys Acta. 2002 Oct 10;1573(1):21-5
12383937
Biol Chem. 2002 Jun;383(6):969-75
12222686
J Genet. 1949 Dec;49(3):264-85
24536673
Nat Genet. 2000 Jan;24(1):53-6
10615127
Nature. 2000 Oct 12;407(6805):703-10
11048710
J Biol Chem. 2003 Jan 3;278(1):14-7
12435741
Nucleic Acids Res. 1998 Mar 1;26(5):1173-8
9469823
Eur J Biochem. 2004 Aug;271(15):3190-9
15265038
Environ Health Perspect. 2004 Jul;112(10):1099-103
15238284
Nat Genet. 2003 Jul;34(3):239-41
12833042
Toxicology. 1999 Apr 15;133(2-3):139-45
10378480
Mol Cell Biochem. 2004 Jan;255(1-2):93-101
14971650
Mol Cell Biol. 1998 Dec;18(12):7590-601
9819445
J Biol Chem. 1998 Nov 27;273(48):32049-54
9822679
Annu Rev Genet. 1999;33:533-64
10690417
Biochemistry. 2003 Jul 1;42(25):7682-93
12820877
J Biol Chem. 1998 Apr 17;273(16):9837-41
9545323
J Biol Chem. 2004 Oct 15;279(42):43879-85
15297450
J Biol Chem. 1993 Oct 5;268(28):21372-83
8407977
J Mol Biol. 2000 Sep 15;302(2):327-38
10970737
Cell. 1997 Dec 26;91(7):995-1005
9428522
J Clin Oncol. 2003 Mar 15;21(6):1174-9
12637487
Am J Hum Genet. 2002 Jan;70(1):26-37
11709755
Nucleic Acids Res. 2002 Nov 1;30(21):4700-8
12409461
Curr Opin Genet Dev. 1999 Feb;9(1):89-96
10072354
Antimicrob Agents Chemother. 2004 Aug;48(8):2876-82
15273095
Curr Opin Struct Biol. 2003 Apr;13(2):249-55
12727520
J Biol Chem. 2001 Sep 7;276(36):34339-47
11454861
Nature. 2000 Oct 12;407(6805):711-7
11048711
Circulation. 2004 Jun 29;109(25):3196-201
15184277
Biochem Biophys Res Commun. 2004 Aug 13;321(1):21-5
15358209
Altern Med Rev. 1998 Aug;3(4):262-70
9727078
J Biol Chem. 2000 Aug 25;275(34):26556-65
10854441
EMBO J. 1997 Jul 16;16(14):4467-76
9250691
Environ Health Perspect. 2002 Oct;110 Suppl 5:797-9
12426134
J Biol Chem. 1999 Sep 17;274(38):26668-82
10480869
Mutat Res. 2003 Dec 10;533(1-2):107-20
14643415
J Biol Chem. 2003 Oct 10;278(41):39558-64
12893829
Carcinogenesis. 2000 Nov;21(11):2097-104
11062174
Biochim Biophys Acta. 2000 May 1;1465(1-2):190-8
10748254
Nat Genet. 2003 Jul;34(3):326-9
12796780
Food Chem Toxicol. 2002 Aug;40(8):1179-84
12067581
Annu Rev Biochem. 1996;65:101-33
8811176
J Biol Chem. 1997 Sep 19;272(38):23811-7
9295328
Int J Biochem Cell Biol. 2002 May;34(5):516-24
11906822
Cell Mol Biol Lett. 2004;9(1):83-94
15048153