| Project/Area Number |
20570137
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Functional biochemistry
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| Research Institution | Fukushima Medical University |
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Principal Investigator |
HOMMA MiwakoK. Fukushima Medical University, 医学部, 准教授 (40192538)
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| Project Period (FY) |
2008 – 2010
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| Project Status |
Completed (Fiscal Year 2010)
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| Budget Amount *help |
¥4,940,000 (Direct Cost: ¥3,800,000、Indirect Cost: ¥1,140,000)
Fiscal Year 2010: ¥1,560,000 (Direct Cost: ¥1,200,000、Indirect Cost: ¥360,000)
Fiscal Year 2009: ¥1,560,000 (Direct Cost: ¥1,200,000、Indirect Cost: ¥360,000)
Fiscal Year 2008: ¥1,820,000 (Direct Cost: ¥1,400,000、Indirect Cost: ¥420,000)
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| Keywords | カゼインキナーゼ2 / CK2 / キナーゼ / 細胞周期 / クロマチン / リン酸化 / 核機能 / セリン・スレオニン・キナーゼ / クロマチン制御 |
|---|
| Research Abstract |
Protein kinase CK2 is a highly conserved serine/threonine kinase that functions in multiple cellular processes including cell growth and development. It is typically found in tetrameric complexes consisting of two catalytic α and/or α' subunits, and two regulatory β subunits. We reported the cell-cycle dependent association of CK2 with adenomatous polyposis coli (APC) that regulates CK2 activity, and identified its downstream target as eukaryotic translation initiation factor 5 (eIF5). Here we demonstrate that a pool of CK2α subunits translocate into the nucleus in G1 phase of the cell cycle, when serum-starved normal human fibroblasts are simulated by FBS, whereas the β subunits localize to the nuclear fraction later than α. Translocation of αβ subunits associate with enhanced phosphorylation of these molecules. Pretreatment with a potent ATP competitive inhibitors reduce nuclear localization of CK2α after FBS stimuli. Similarly, phosphorylation site mutants in CK2α partially inhibit their accumulation in the nuclear fraction following FBS stimuli. These results suggest the involvement of multiple kinases that phosphorylate CK2 for the growth factor-induced nuclear localization. Co-immunoprecipitation experiments using anti-CK2α antibodies, followed by mass spectrometry analysis, identified nuclear proteins that associate with CK2α in a cell -cycle dependent manner. As one of these proteins, hnRNPs is also a phosphoprotein in vivo. FRAP experiments on living stable cell lines expressing GFP-CK2α protein indicate that the nucleocytoplasmic distribution of CK2 subunits may be regulated in a cell cycle-dependent manner. These results support a role for CK2 in response to growth stimuli, and also the possible involvement of CK2α subunit as isolated entities exerting specific functions in complex with other cellular partners in the nuclear fraction, during the progression of cell cycle.
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