2001 Fiscal Year Final Research Report Summary
Molecular cell pharmacology of novel smooth muscle regulation molecule
| Project/Area Number |
12672212
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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 |
応用薬理学・医療系薬学
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| Research Institution | Mie University |
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Principal Investigator |
NAKA Michiko Mie University, Faculty of Medicine, Assistant, 医学部, 助手 (10093139)
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| Co-Investigator(Kenkyū-buntansha) |
TSUNODA Hiroshi Mie University, Faculty of Medicine, Assistant, 医学部, 助手 (20314114)
NISHIMURA Yuhei Mie University, Faculty of Medicine, Assistant, 医学部, 助手 (30303720)
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| Project Period (FY) |
2000 – 2001
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| Keywords | smooth muscle / S100 family / Calcium / Actin / Actin binding gites / calponin / S100C / Actin activated Mg myosin ATPase activity |
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| Research Abstract |
S100C is a novel member of the S100 protein family which we purified a novel Ca^<2+>-binding protein and abundant in smooth muscle. We found that S100C inhibits the smooth muscle actin-activated myosin Mg^<2+>-ATPase activity in a dose-dependent manner. Calmodulin and S100L protein did not inhibit actin-activated myosin Mg^<2+>-ATPase activity. S100ao and S100b also did not exhibit any effects. These results suggest that the inhibitory effects of S100C on the actin-activated myosin Mg^<2+>-ATPase activity is specific. Moreover, we investigated whether Ca^<2+>-binding proteins(calmodulin, S100ao, S100b, S100L and S100C) can reverse the inhibitory effects of calponin, a actin-binding protein on the actin-activated myosin Mg^<2+>-ATPase activity. Calmodulin, S100ao and S100b reversed the inhibitory effect of calponin in a Ca^<2+>-dependent manner, S100L had no effect, and S100C had additional inhibitory effects. Furthermore, S100C was found to bind to actin with a stoichiometry of 1 : 6〜7 in the presence of Ca^<2+> and with an affinity of 1 x 10^<-6> M by cosedimentation assays. Moreover, we cross-linked S100C to actin using the carbodiimide zero-length cross-linker 1-ethyl-3-[3-(dimethylamino)propyl] carbodiimide (EDC) in the presence of N-hydroxysuccinimide (NHS). The cross-linked peptides were purified after trypsin digestion, and cross-linked sites were identified by amino acid sequencing. Amino acid sequence analysis indicated that the cross-linking occurred between Lys-191 of actin and Glu-44 of S100C. The results suggest that S100C might be involved in the regulation of actin-activated myosin Mg^<2+>-ATPase activity through its Ca^<2+>-dependent interaction with actin filaments.
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