title: Ku and DNA-dependent protein kinase dynamic conformations and assembly regulate DNA binding and the initial non-homologous end joining complex.
abstract: DNA double strand break (DSB) repair by non-homologous end joining (NHEJ) is initiated by DSB detection by Ku70/80 (Ku) and DNA-dependent protein kinase catalytic subunit (DNA-PKcs) recruitment, which promotes pathway progression through poorly defined mechanisms. Here, Ku and DNA-PKcs solution structures alone and in complex with DNA, defined by x-ray scattering, reveal major structural reorganizations that choreograph NHEJ initiation. The Ku80 C-terminal region forms a flexible arm that extends from the DNA-binding core to recruit and retain DNA-PKcs at DSBs. Furthermore, Ku- and DNA-promoted assembly of a DNA-PKcs dimer facilitates trans-autophosphorylation at the DSB. The resulting site-specific autophosphorylation induces a large conformational change that opens DNA-PKcs and promotes its release from DNA ends. These results show how protein and DNA interactions initiate large Ku and DNA-PKcs rearrangements to control DNA-PK biological functions as a macromolecular machine orchestrating assembly and disassembly of the initial NHEJ complex on DNA.
authors.affiliation: Physical Biosciences Division, Department of Molecular Biology, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA. mhammel@lbl.gov
authors.forename: Michal
authors.initials: M
authors.lastname: Hammel
authors.forename: Yaping
authors.initials: Y
authors.lastname: Yu
authors.forename: Brandi L
authors.initials: BL
authors.lastname: Mahaney
authors.forename: Brandon
authors.initials: B
authors.lastname: Cai
authors.forename: Ruiqiong
authors.initials: R
authors.lastname: Ye
authors.forename: Barry M
authors.initials: BM
authors.lastname: Phipps
authors.forename: Robert P
authors.initials: RP
authors.lastname: Rambo
authors.forename: Greg L
authors.initials: GL
authors.lastname: Hura
authors.forename: Martin
authors.initials: M
authors.lastname: Pelikan
authors.forename: Sairei
authors.initials: S
authors.lastname: So
authors.forename: Ramin M
authors.initials: RM
authors.lastname: Abolfath
authors.forename: David J
authors.initials: DJ
authors.lastname: Chen
authors.forename: Susan P
authors.initials: SP
authors.lastname: Lees-Miller
authors.forename: John A
authors.initials: JA
authors.lastname: Tainer
mesh_terms: D034961:Antigens, Nuclear / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D004247:DNA / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D053903:DNA Breaks, Double-Stranded; D004268:DNA-Binding Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D000072200:Ku Autoantigen; D011485:Protein Binding / Q000502:physiology; D017434:Protein Structure, Tertiary / Q000502:physiology
chemical_list: D034961:Antigens, Nuclear; D004268:DNA-Binding Proteins; D004247:DNA; C000606509:Xrcc6 protein, human; D000072200:Ku Autoantigen