In addition to its role in NHEJ, Ku is also required for telomere length maintenance and subtelomeric gene silencing.[3]
Ku was originally identified when patients with systemic lupus erythematosus were found to have high levels of autoantibodies to the protein.[1]
Aging
Mouse embryonic stem cells with homozygous Ku70 mutations, that is Ku70−/− cells, have markedly increased sensitivity to ionizing radiation compared to heterozygous Ku70+/− or wild-type Ku70+/+ embryonic stem cells.[4] Mutant mice deficient in Ku70 exhibit early aging.[5] Using several specific criteria of aging, the mutant mice were found to display the same aging signs as control mice, but at a considerably earlier chronological age. These results suggest that reduced ability to repair DNA double-strand breaks causes early aging, and that the wild-type Ku70 gene plays an important role in longevity assurance.[6] (Also see DNA damage theory of aging.)
Nomenclature
Ku70 has been referred to by several names including:
Lupus Ku autoantigen protein p70
ATP-dependent DNA helicase 2 subunit 1
X-ray repair complementing defective repair in Chinese hamster cells 6
↑Pace P, Mosedale G, Hodskinson MR, Rosado IV, Sivasubramaniam M, Patel KJ (Jul 2010). "Ku70 corrupts DNA repair in the absence of the Fanconi anemia pathway". Science. 329 (5988): 219–23. doi:10.1126/science.1192277. PMID20538911.
↑Song K, Jung Y, Jung D, Lee I (Mar 2001). "Human Ku70 interacts with heterochromatin protein 1alpha". The Journal of Biological Chemistry. 276 (11): 8321–7. doi:10.1074/jbc.M008779200. PMID11112778.
↑Goudelock DM, Jiang K, Pereira E, Russell B, Sanchez Y (Aug 2003). "Regulatory interactions between the checkpoint kinase Chk1 and the proteins of the DNA-dependent protein kinase complex". The Journal of Biological Chemistry. 278 (32): 29940–7. doi:10.1074/jbc.M301765200. PMID12756247.
↑Schild-Poulter C, Pope L, Giffin W, Kochan JC, Ngsee JK, Traykova-Andonova M, Haché RJ (May 2001). "The binding of Ku antigen to homeodomain proteins promotes their phosphorylation by DNA-dependent protein kinase". The Journal of Biological Chemistry. 276 (20): 16848–56. doi:10.1074/jbc.M100768200. PMID11279128.
↑Goedecke W, Eijpe M, Offenberg HH, van Aalderen M, Heyting C (Oct 1999). "Mre11 and Ku70 interact in somatic cells, but are differentially expressed in early meiosis". Nature Genetics. 23 (2): 194–8. doi:10.1038/13821. PMID10508516.
↑Ko L, Chin WW (Mar 2003). "Nuclear receptor coactivator thyroid hormone receptor-binding protein (TRBP) interacts with and stimulates its associated DNA-dependent protein kinase". The Journal of Biological Chemistry. 278 (13): 11471–9. doi:10.1074/jbc.M209723200. PMID12519782.
↑Grandvaux N, Grizot S, Vignais PV, Dagher MC (Feb 1999). "The Ku70 autoantigen interacts with p40phox in B lymphocytes". Journal of Cell Science. 112 (4): 503–13. PMID9914162.
↑Ohta S, Shiomi Y, Sugimoto K, Obuse C, Tsurimoto T (Oct 2002). "A proteomics approach to identify proliferating cell nuclear antigen (PCNA)-binding proteins in human cell lysates. Identification of the human CHL12/RFCs2-5 complex as a novel PCNA-binding protein". The Journal of Biological Chemistry. 277 (43): 40362–7. doi:10.1074/jbc.M206194200. PMID12171929.
↑Li B, Comai L (Sep 2000). "Functional interaction between Ku and the werner syndrome protein in DNA end processing". The Journal of Biological Chemistry. 275 (37): 28349–52. doi:10.1074/jbc.C000289200. PMID10880505.
Further reading
Smider V, Chu G (Jun 1997). "The end-joining reaction in V(D)J recombination". Seminars in Immunology. 9 (3): 189–97. doi:10.1006/smim.1997.0070. PMID9200330.
Featherstone C, Jackson SP (May 1999). "Ku, a DNA repair protein with multiple cellular functions?". Mutation Research. 434 (1): 3–15. doi:10.1016/s0921-8777(99)00006-3. PMID10377944.