Visualization of DNA-induced conformational changes in the DNA repair kinase DNA-PKcs.
The catalytic subunit of the DNA-dependent protein kinase (DNA-PKcs) is essential for the repair of double-stranded DNA breaks (DSBs) in non- homologous end joining (NHEJ) and during V(D)J recombination. DNA-PKcs binds single- and double-stranded DNA in vitro, and in vivo the Ku heterodimer probably helps recruit it to DSBs with high affinity. Once loaded onto DNA, DNA-PKcs acts as a scaffold for other repair factors to generate a multiprotein complex that brings the two DNA ends together. Human DNA-PKcs has been analysed by electron microscopy in the absence and presence of double-stranded DNA, and the three-dimensional reconstruction of DNA-bound DNA-PKcs displays large conformational changes when compared with the unbound protein. DNA-PKcs seems to use a palm-like domain to clip onto the DNA, and this new conformation correlates with the activation of the kinase. We suggest that the observed domain movements might help the binding and maintenance of DNA-PKcs' interaction with DNA at the sites of damage, and that these conformational changes activate the kinase.
Centro de Investigaciones Biológicas, Consejo Superior de Investigaciones Científicas, Ramiro de Maeztu 9, Campus Universidad Complutense, 28040 Madrid, Spain.
Jasminka
J
Boskovic
Angel
A
Rivera-Calzada
Joseph D
JD
Maman
Pablo
P
Chacón
Keith R
KR
Willison
Laurence H
LH
Pearl
Oscar
O
Llorca
D064007:Ataxia Telangiectasia Mutated Proteins; D001483:Base Sequence; D018797:Cell Cycle Proteins; D004247:DNA / Q000235:genetics / Q000378:metabolism*; D004249:DNA Damage; D004260:DNA Repair / Q000502:physiology*; D051747:DNA-Activated Protein Kinase; D004268:DNA-Binding Proteins; D004789:Enzyme Activation; D006367:HeLa Cells; D006801:Humans; D066298:In Vitro Techniques; D008854:Microscopy, Electron; D008954:Models, Biological; D008958:Models, Molecular; D009687:Nuclear Proteins; D011487:Protein Conformation; D017346:Protein Serine-Threonine Kinases / Q000737:chemistry* / Q000378:metabolism* / Q000648:ultrastructure; D021122:Protein Subunits; D025521:Tumor Suppressor Proteins
D018797:Cell Cycle Proteins; D004268:DNA-Binding Proteins; D009687:Nuclear Proteins; D021122:Protein Subunits; D025521:Tumor Suppressor Proteins; D004247:DNA; C576324:ATM protein, human; D064007:Ataxia Telangiectasia Mutated Proteins; D051747:DNA-Activated Protein Kinase; C497263:PRKDC protein, human; D017346:Protein Serine-Threonine Kinases