DNA-dependent protein kinase regulates DNA end resection in concert with Mre11-Rad50-Nbs1 (MRN) and ataxia telangiectasia-mutated (ATM).
The resection of DNA double strand breaks initiates homologous recombination (HR) and is critical for genomic stability. Using direct measurement of resection in human cells and reconstituted assays of resection with purified proteins in vitro, we show that DNA-dependent protein kinase catalytic subunit (DNA-PKcs), a classic nonhomologous end joining factor, antagonizes double strand break resection by blocking the recruitment of resection enzymes such as exonuclease 1 (Exo1). Autophosphorylation of DNA-PKcs promotes DNA-PKcs dissociation and consequently Exo1 binding. Ataxia telangiectasia-mutated kinase activity can compensate for DNA-PKcs autophosphorylation and promote resection under conditions where DNA-PKcs catalytic activity is inhibited. The Mre11-Rad50-Nbs1 (MRN) complex further stimulates resection in the presence of Ku and DNA-PKcs by recruiting Exo1 and enhancing DNA-PKcs autophosphorylation, and it also inhibits DNA ligase IV/XRCC4-mediated end rejoining. This work suggests that, in addition to its key role in nonhomologous end joining, DNA-PKcs also acts in concert with MRN and ataxia telangiectasia-mutated to regulate resection and thus DNA repair pathway choice.
From the Howard Hughes Medical Institute, Department of Molecular Biosciences, and Institute for Cellular and Molecular Biology, University of Texas at Austin, Austin, Texas 78712.
Yi
Y
Zhou
Tanya T
TT
Paull
D017766:Acid Anhydride Hydrolases; D064007:Ataxia Telangiectasia Mutated Proteins / Q000235:genetics / Q000378:metabolism*; D018797:Cell Cycle Proteins / Q000235:genetics / Q000378:metabolism*; D059766:DNA End-Joining Repair / Q000502:physiology*; D004265:DNA Helicases / Q000235:genetics / Q000378:metabolism; D000072481:DNA Ligase ATP; D011088:DNA Ligases / Q000235:genetics / Q000378:metabolism; D045643:DNA Repair Enzymes / Q000235:genetics / Q000378:metabolism*; D051747:DNA-Activated Protein Kinase / Q000235:genetics / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D005090:Exodeoxyribonucleases / Q000235:genetics / Q000378:metabolism; D057809:HEK293 Cells; D006801:Humans; D000072200:Ku Autoantigen; D000076228:MRE11 Homologue Protein; D046912:Multiprotein Complexes / Q000235:genetics / Q000378:metabolism*; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism*; D010766:Phosphorylation
D018797:Cell Cycle Proteins; D004268:DNA-Binding Proteins; C000607893:LIG4 protein, human; C121766:MRE11 protein, human; D046912:Multiprotein Complexes; C112156:NBN protein, human; D009687:Nuclear Proteins; C101467:XRCC4 protein, human; C576324:ATM protein, human; D064007:Ataxia Telangiectasia Mutated Proteins; D051747:DNA-Activated Protein Kinase; C114331:EXO1 protein, human; D005090:Exodeoxyribonucleases; D000076228:MRE11 Homologue Protein; D017766:Acid Anhydride Hydrolases; C112158:RAD50 protein, human; D004265:DNA Helicases; C106893:XRCC5 protein, human; D000072200:Ku Autoantigen; D011088:DNA Ligases; D045643:DNA Repair Enzymes; D000072481:DNA Ligase ATP
DNA Damage Response; DNA Enzymes; DNA Recombination; DNA Repair; DNA-binding Protein; Protein Kinases