title: hMSH2 recruits ATR to DNA damage sites for activation during DNA damage-induced apoptosis.
abstract: DNA damage response (DDR) activates a complex signaling network that triggers DNA repair, cell cycle arrest, and/or cell death. Depending on the type and severity of DNA lesion, DDR is controlled by "master" regulators including ATM and ATR protein kinases. Cisplatin, a major chemotherapy drug that cross-links DNA, induces ATR-dependent DDR, resulting in apoptosis. However, it is unclear how ATR is activated. To identify the key regulators of ATR, we analyzed the proteins that associate with ATR after cisplatin treatment by blue native-PAGE and co-immunoprecipitation. The mismatch repair protein hMSH2 was found to be a major ATR-binding protein. Functionally, ATR activation and its recruitment to nuclear foci during cisplatin treatment were attenuated, and DNA damage signaling, involving Chk2, p53, and PUMA-α, was suppressed in hMSH2-deficient cells. ATR activation induced by the DNA methylating agent N-methyl-N-nitrosourea was also shown to be hMSH2-dependent. Intriguingly, hMSH2-mediated ATR recruitment and activation appeared independent of replication protein A, Rad17, and the Rad9-Hus1-Rad1 protein complex. Together the results support a hMSH2-dependent pathway of ATR activation and downstream Chk2/p53 signaling.
authors.affiliation: Department of Cellular Biology and Anatomy, Medical College of Georgia, Augusta, Georgia 30912, USA.
authors.forename: Navjotsingh
authors.initials: N
authors.lastname: Pabla
authors.forename: Zhengwei
authors.initials: Z
authors.lastname: Ma
authors.forename: Michael A
authors.initials: MA
authors.lastname: McIlhatton
authors.forename: Richard
authors.initials: R
authors.lastname: Fishel
authors.forename: Zheng
authors.initials: Z
authors.lastname: Dong
mesh_terms: D021581:Active Transport, Cell Nucleus / Q000187:drug effects / Q000502:physiology; D000477:Alkylating Agents / Q000494:pharmacology; D000818:Animals; D017209:Apoptosis / Q000187:drug effects / Q000502:physiology*; D064007:Ataxia Telangiectasia Mutated Proteins; D018797:Cell Cycle Proteins / Q000235:genetics / Q000378:metabolism*; D002467:Cell Nucleus / Q000235:genetics / Q000378:metabolism*; D064447:Checkpoint Kinase 2; D002945:Cisplatin / Q000494:pharmacology; D003432:Cross-Linking Reagents / Q000494:pharmacology; D004249:DNA Damage / Q000187:drug effects / Q000502:physiology*; D057809:HEK293 Cells; D006367:HeLa Cells; D006801:Humans; D008770:Methylnitrosourea / Q000494:pharmacology; D051379:Mice; D008817:Mice, Mutant Strains; D051718:MutS Homolog 2 Protein / Q000235:genetics / Q000378:metabolism*; D017346:Protein Serine-Threonine Kinases / Q000235:genetics / Q000378:metabolism*; D051716:Replication Protein A / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects / Q000502:physiology; D016159:Tumor Suppressor Protein p53 / Q000235:genetics / Q000378:metabolism
chemical_list: D000477:Alkylating Agents; D018797:Cell Cycle Proteins; D003432:Cross-Linking Reagents; C549605:HUS1 protein, human; C509939:Hus1 protein, mouse; C113575:Rad17 protein, human; D051716:Replication Protein A; C495901:TP53 protein, human; D016159:Tumor Suppressor Protein p53; C069930:rad9 protein; D008770:Methylnitrosourea; C576897:Atr protein, mouse; D064447:Checkpoint Kinase 2; C576597:ATR protein, human; D064007:Ataxia Telangiectasia Mutated Proteins; C578634:CHEK2 protein, human; C578633:Chek2 protein, mouse; D017346:Protein Serine-Threonine Kinases; C497172:MSH2 protein, human; D051718:MutS Homolog 2 Protein; D002945:Cisplatin