| Project/Area Number |
18390234
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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 | Yamaguchi University |
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Principal Investigator |
YANO Masafumi Yamaguchi University, Hospital, Associate Professor (90294628)
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| Co-Investigator(Kenkyū-buntansha) |
YAMAMOTO Takeshi Yamaguchi University, Graduate School of Medicine, Assistant Professor (50363122)
IKEDA Yasuhiro Yamaguchi University, School of Medicine, Associate Professor (00260349)
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| Project Period (FY) |
2006 – 2007
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| Project Status |
Completed (Fiscal Year 2007)
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| Budget Amount *help |
¥15,570,000 (Direct Cost: ¥14,400,000、Indirect Cost: ¥1,170,000)
Fiscal Year 2007: ¥5,070,000 (Direct Cost: ¥3,900,000、Indirect Cost: ¥1,170,000)
Fiscal Year 2006: ¥10,500,000 (Direct Cost: ¥10,500,000)
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| Keywords | sarcoplasmic reticulum / scalcium / rvanodine receptor / heart failure / lethal arrhythmia / point mutation |
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| Research Abstract |
Two domains within the ryanodine receptor (RyR2) of sarcoplasmic reticulum (SR) {N-terminal (0-600) and central (2000-2500) domains} was found to interact with each other as a regulatory switch for channel gating. We previously reported that K201 (JTV519) inhibits Ca^<2+> leak by correcting the defective inter-domain interaction between the two domains in failing hearts. Here, we identified the K201-binding domain and diaracterizedtherole ofthis novel domain on RyR2 channel gating.
An assay using a quartz-crystal microbalance revealed that K201 specifically bound to recornbinant RyR2 fragment: 1741. 2270 in the 1-2750 region. By further analysis of the fragnent1741-2270, 201 was found to specifically bind to its sub-fragment2114-2149. Using the peptide matching this sub-fragment (DP2114-2149)as a carrier, the RyR2 was specifically labeled with methylcoumarin acetate(MCA). Moreover, of several recombinant RyR2 fragments, only fragment 2234-2750 was specifically MCA-labeled; this suggests that the K201 binding domain2114-2149 binds with domain 2234-2750. Addition of DP2114-2149 to the MCA-labeled SR interfered with the interaction between domain2114-2149 and domain2234-2750 causing domain unzipping, as evidenced by an increased accessibility of the bound MCA to a large-size fluorescence quencher. In failing cardiomyocytes, the frequency of spontaneous Ca^<2+> spark (CaSF) was much higher than normal cardiomyocytes (p<0.01), whereas incorporation of DP2114-2149 markedly decreased CaSF to normal level; the same effect as that produced by K201.
In conclusion, we first identified the K201-binding site as domain2114-2149 of RyR2 Interruption of the inter-domain interaction between the domain2114-2149 and central domain2234-2750 seems to mediate stabilization of RyR2 in failing hearts, which may lead to a novel therapeutic strategy against heart failure and perhaps lethal arrhythmia.
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