Autophosphorylation of DNA-dependent protein kinase regulates DNA end processing and may also alter double-strand break repair pathway choice.
Two highly conserved double-strand break (DSB) repair pathways, homologous recombination (HR) and nonhomologous end joining (NHEJ), function in all eukaryotes. How a cell chooses which pathway to utilize is an area of active research and debate. During NHEJ, the DNA-dependent protein kinase (DNA-PK) functions as a "gatekeeper" regulating DNA end access. Here, we provide evidence that DNA-PK regulates DNA end access via its own autophosphorylation. We demonstrated previously that autophosphorylation within a major cluster of sites likely mediates a conformational change that is critical for DNA end processing. Furthermore, blocking autophosphorylation at these sites inhibits a cell's ability to utilize the other major double-strand break repair pathway, HR. Here, we define a second major cluster of DNA-PK catalytic subunit autophosphorylation sites. Whereas blocking phosphorylation at the first cluster inhibits both end processing and HR, blocking phosphorylation at the second cluster enhances both. We conclude that separate DNA-PK autophosphorylation events may function reciprocally by not only regulating DNA end processing but also affecting DSB repair pathway choice.
Cui
Xiaoping
X
College of Veterinary Medicine and Department of Pathobiology and Diagnostic Investigation, Michigan State University, East Lansing, 48824, USA.
Yu
Yaping
Y
Gupta
Shikha
S
Cho
Young-Moon
YM
Lees-Miller
Susan P
SP
Meek
Katheryn
K
D000409:Alanine / Q000235:genetics / Q000378:metabolism; D000595:Amino Acid Sequence; D019943:Amino Acid Substitution; D004247:DNA / Q000235:genetics / Q000378:metabolism*; D004249:DNA Damage; D004260:DNA Repair; D051747:DNA-Activated Protein Kinase / Q000235:genetics / Q000378:metabolism*; D006657:Histones / Q000378:metabolism; D006801:Humans; D008969:Molecular Sequence Data; D009154:Mutation; D010766:Phosphorylation; D011836:Radiation Tolerance / Q000235:genetics; D011995:Recombination, Genetic
D006657:Histones; D004247:DNA; D051747:DNA-Activated Protein Kinase; D000409:Alanine