DNA-PKcs Antibody

DNA-dependent protein kinase (DNA-PK) is an important factor in the repair of double-stranded breaks in DNA. Cells lacking DNA-PK or in which DNA-PK is inhibited fail to show proper nonhomologous end-joining (NHEJ) (1-7). DNA-PK is composed of two DNA-binding subunits (Ku70 and Ku86) and one 450 kDa catalytic subunit (DNA-PKcs) (8). It is thought that a heterodimer of Ku70 and Ku86 binds to double-stranded DNA broken ends before DNA-PKcs binds and is activated (1,9). Activated DNA-PKcs is a serine/threonine kinase that has been shown to phosphorylate a number of proteins in vitro, including p53, transcription factors, RNA polymerase, and Ku70/Ku86 (10,11). DNA-PKcs autophosphorylation at multiple sites, including Thr2609 and Ser2056, results in an inactivation of DNA-PK kinase activity and NHEJ ability (12,13). It has been demonstrated, however, that DNA-PK preferentially phosphorylates substrates before it autophosphorylates, suggesting that DNA-PK autophosphorylation may play a role in disassembly of the DNA repair machinery (14,15). Autophosphorylation at Thr2609 has also been shown to be required for DNA-PK-mediated double-strand break repair, and phosphorylated DNA-PK co-localizes with H2A.X and 53BP1 at sites of DNA damage (16). Phosphorylation at Ser2056 occurs in response to double-stranded DNA breaks and ATM activation (17). 1.Gottlieb, T.M. and Jackson, S.P. (1993) Cell 72, 131-42. 2.Hartley, K.O. et al. (1995) Cell 82, 849-56. 3.Rosenzweig, K.E. et al. (1997) Clin Cancer Res 3, 1149-56. 4.Jackson, S.P. and Jeggo, P.A. (1995) Trends Biochem Sci 20, 412-5. 5.Roth, D.B. et al. (1995) Curr Biol 5, 496-9. 6.Baumann, P. and West, S.C. (1998) Proc Natl Acad Sci U S A 95, 14066-70. 7.Chen, S. et al. (2001) J Biol Chem 276, 24323-30. 8.Jeggo, P.A. (1997) Mutat Res 384, 1-14. 9.Suwa, A. et al. (1994) Proc Natl Acad Sci U S A 91, 6904-8. 10.Anderson, C.W. and Lees-Miller, S.P. (1992) Crit Rev Eukaryot Gene Expr 2, 283-314. 11.Kuhn, A. et al. (1995) Genes Dev 9, 193-203. 12.Chan, D.W. and Lees-Miller, S.P. (1996) J Biol Chem 271, 8936-41. 13.Douglas, P. et al. (2002) Biochem. J. 368, 243-51. 14.Lees-Miller, S.P. et al. (1992) Mol Cell Biol 12, 5041-9. 15.Jackson, S.P. et al. (1990) Cell 63, 155-65. 16.Chan, D.W. et al. (2002) Genes Dev 16, 2333-8. 17.Yajima, H. et al. (2009) J Mol Biol 385, 800-10.