Ku70

Ku70は、XRCC6遺伝子にコードされているタンパク質である。 Ku70はKu80とヘテロ二量体を形成して、DNA修復のための非相同末端結合（NHEJ）経路に必要なKu自己抗原となる。また、NHEJ経路を利用して哺乳類の免疫系の抗原多様性を増大させるV(D)J遺伝子再構成にも要求される。また、NHEJ経路が関与しない、テロメア長の維持とサブテロメア遺伝子サイレンシングにも不可欠な役割を果たす。 Kuは、全身性エリテマトーデスの患者がタンパク質に対して高レベルの自己抗体を持っていることが判明したときに最初に同定された。 ホモ接合型Ku70変異を持つマウス胚性幹細胞（Ku70 -/-細胞）において、ヘテロ接合型Ku70 +/-または野生型Ku70 + / +胚性幹細胞と比較して、電離放射線に対する感受性は著しく増加した。Ku70を欠損した変異マウスは早期老化を示す。いくつかの老化の基準に基づいて分析が行われたところ、変異マウスは対照マウスと同じ老化の兆候を示すが、そのときの年齢は対照マウスと比べて著しく早いことが判明した。これらの結果は、野生型Ku70遺伝子によるDNA二本鎖切断を修復する能力の低下が早期老化を引き起こし、この遺伝子が寿命の保証に重要な役割を果たしていることを示唆する。 この遺伝子の突然変異については、自閉症の24家族のエクソーム解析の研究結果が記述されている。これは、この遺伝子が自閉症の発症に関与している可能性があることを示唆しており、さらなる調査が期待されている。 Ku70は、以下で記述するいくつかの別名でも呼ばれる。 ループスKu自己抗原タンパク質p70（Lupus Ku autoantigen protein p70） ATP依存性DNAヘリカーゼ2サブユニット1（ATP-dependent DNA helicase 2 subunit 1） X-ray repair complementing defective repair in Chinese hamster cells 6 X線修復交差補完タンパク質6（XRCC6: X-ray repair cross-complementing 6） Ku70は以下の生体分子と相互作用する。 CBX5 CHEK1 CREBBP GCN5L2 HOXC4 Ku80 MRE11A NCOA6 NCF4 PCNA PTTG1 RPA2 TERF2 TERT VAV1 WRN ^ a b c GRCh38: Ensembl release 89: ENSG00000196419 - Ensembl, May 2017 ^ a b c GRCm38: Ensembl release 89: ENSMUSG00000022471 - Ensembl, May 2017 ^ Human PubMed Reference: ^ Mouse PubMed Reference: ^ a b “Entrez Gene: XRCC6 X-ray repair complementing defective repair in Chinese hamster cells 6 (Ku autoantigen, 70kDa)”. アメリカ国立生物工学情報センター (2021年8月2日). 2021年8月7日閲覧。 ^ Paul Pace, Georgina Mosedale, Michael Hodskinson, Ivan V. 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PMC 134248. PMID 12177300. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC134248/.  ^ “Functional interaction between Ku and the werner syndrome protein in DNA end processing”. The Journal of Biological Chemistry 275 (37): 28349–52. (Sep 2000). doi:10.1074/jbc.C000289200. PMID 10880505.  “The end-joining reaction in V(D)J recombination”. Seminars in Immunology 9 (3): 189–97. (Jun 1997). doi:10.1006/smim.1997.0070. PMID 9200330.  “Ku, a DNA repair protein with multiple cellular functions?”. Mutation Research 434 (1): 3–15. (May 1999). doi:10.1016/s0921-8777(99)00006-3. PMID 10377944.  “Dimerization, translocation and localization of Ku70 and Ku80 proteins”. Journal of Radiation Research 43 (3): 223–36. (Sep 2002). doi:10.1269/jrr.43.223. PMID 12518983.  PDBe-KB：PDBで利用可能なヒトX線修復交差補完タンパク質6の構造情報を提供する。