| Project/Area Number |
18390239
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Circulatory organs internal medicine
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| Research Institution | Keio University |
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Principal Investigator |
SANO Motoaki Keio University, School of Medicine, Assistant professor (30265798)
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| Project Period (FY) |
2006 – 2007
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| Project Status |
Completed (Fiscal Year 2007)
|
| Budget Amount *help |
¥17,750,000 (Direct Cost: ¥15,500,000、Indirect Cost: ¥2,250,000)
Fiscal Year 2007: ¥9,750,000 (Direct Cost: ¥7,500,000、Indirect Cost: ¥2,250,000)
Fiscal Year 2006: ¥8,000,000 (Direct Cost: ¥8,000,000)
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| Keywords | cardiac hypertrophy / transcription / energy metabolism / signal transduction / P-TEFb / PGC-1α / HEXIM-1 / ミトコンドリア / 心不全 / アポトーシス |
|---|
| Research Abstract |
Intramolecular control of protein stability, subnuclear compartmentalization, and coactivator function of peroxisome proliferator-activated receptor gamma coactivator 1alpha
Peroxisome proliferator-activated receptor gamma coactivator (PGC)-1 is a critical transcriptional regulator of energy metabolism. Here we found that PGC-1alpha is a short lived and aggregation-prone protein. PGC-1alpha localized throughout the nucleoplasm and was rapidly destroyed via the ubiquitin-proteasome pathway. Upon proteasome inhibition, PGC-1alpha formed insoluble polyubiquitinated aggregates. Ubiquitination of PGC-1alpha depended on the integrity of the C terminus-containing arginine-serine-rich domains and an RNA recognition motif. Interestingly, ectopically expressed C-terminal fragment of PGC-1alpha was autonomously ubiquitinated and aggregated with promyelocytic leukemia protein. Cooperation of the N-terminal region containing two PEST-like motifs was required for prevention of aggregation and targeti
… More
ng of the polyubiquitinated PGC-1alpha for degradation. This region thereby negatively controlled the aggregation properties of the C-terminal region to regulate protein turnover and intranuclear compartmentalization of PGC-1alpha Exogenous expression of the PGC-1alpha C-terminal fragment interfered with degradation of full-length PGC-1alpha and enhanced its coactivation properties. We concluded that PGC-1alpha function is critically regulated at multiple steps via intramolecular cooperation among several distinct structural domains of the protein.
HEXIM-1 alleviated hypoxia-induced right ventricular hypertrophy
HEXIM-1 is an endogenous inhibitor of Cdk9. To examine the effect of Cdk9 inhibition on the development of cardiac hypertrophy, we developed loss of function model of Cdk9 activity by transgenic over-expression of HEXIM-1. Cardiac-specific HEXIM-1 TG mice and wild-type littermates were subjected to hypoxia (11% O_2). Right ventricular hypertrophy produced by hypoxia was milder in HEXIM-1 TG mice compared to wild-type littermates. Less
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