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ID 106072
タイトル別表記
Homeodomain interacting protein kinase 2はheterochromatin protein 1γとの相互作用を介してDNA損傷応答を制御する
HP1γ as a novel target for HIPK2
著者
赤池, 瑶子 徳島大学大学院医科学教育部(医学専攻)
Kurokawa, Ken Tokushima University
Kajita, Keisuke Tokushima University
Kano, Shizuka Tokushima University
キーワード
DNA damage response
HIPK2
HP1γ
chromatin remodeling
DNA damage repair
資料タイプ
学位論文
抄録
Homeodomain-interacting protein kinase 2 (HIPK2) is a potential tumor suppressor that plays a crucial role in the DNA damage response (DDR) by regulating cell cycle checkpoint activation and apoptosis. However, it is unclear whether HIPK2 exerts distinct roles in DNA damage repair. The aim of this study was to identify novel target molecule(s) of HIPK2, which mediates HIPK2-dependent DNA damage repair. HIPK2-knockdown human colon cancer cells (HCT116) or hipk1/hipk2 double-deficient mouse embryonic fibroblasts could not remove histone H2A.X phosphorylated at Ser139 (γH2A.X) after irradiation with a sublethal dose (10 J/m2) of ultraviolet (UV)-C, resulting in apoptosis. Knockdown of HIPK2 in p53-null HCT116 cells similarly promoted the UV-C-induced γH2A.X accumulation and apoptosis. Proteomic analysis of HIPK2-associated proteins using liquid chromatography-tandem mass spectrometry identified heterochromatin protein 1γ (HP1γ) as a novel target for HIPK2. Immunoprecipitation experiments with HCT116 cells expressing FLAG-tagged HIPK2 and one of the HA-tagged HP1 family members demonstrated that HIPK2 specifically associated with HP1γ, but not with HP1α or HP1β, through its chromo-shadow domain. Mutation of the HP1box motif (883-PTVSV-887) within HIPK2 abolished the association. HP1γ knockdown also enhanced accumulation of γH2A.X and apoptosis after sublethal UV-C irradiation. In vitro kinase assay demonstrated an HP1γ-phosphorylating activity of HIPK2. Sublethal UV-C irradiation phosphorylated HP1γ. This phosphorylation was absent in endogenous HIPK2-silenced cells with HIPK2 3’UTR siRNA. Overexpression of FLAG-HIPK2, but not the HP1box-mutated or kinase-dead HIPK2 mutant, in the HIPK2-silenced cells increased HP1γ binding to trimethylated (Lys9) histone H3 (H3K9me3), rescued the UV-C-induced phosphorylation of HP1γ, triggered release of HP1γ from histone H3K9me3, and suppressed γH2A.X accumulation. Our results suggest that HIPK2-dependent phosphorylation of HP1γ may participate in the regulation of dynamic interaction between HP1γ and histone H3K9me3 to promote DNA damage repair. This HIPK2/HP1γ pathway may uncover a new functional aspect of HIPK2 as a tumor suppressor.
掲載誌名
Oncogene
ISSN
14765594
09509232
cat書誌ID
AA12190066
AA10687380
出版者
Springer Nature
34
26
開始ページ
3463
終了ページ
3473
発行日
2014-08-25
備考
内容要旨・審査要旨・論文本文の公開
内容要旨・審査要旨 : LID201404221016.pdf
論文本文 : k2672_fulltext.pdf
本論文は,著者Yoko Akaikeの学位論文として提出され,学位審査・授与の対象となっている。
著者の申請により要約(2014-05-23公開)に替えて論文全文を公開(2020-01-20)
EDB ID
出版社版DOI
出版社版URL
フルテキストファイル
言語
eng
著者版フラグ
博士論文全文を含む
文科省報告番号
甲第2672号
学位記番号
甲医第1196号
学位授与年月日
2014-03-24
学位名
博士(医学)
学位授与機関
徳島大学
部局
医学系