Molecular mechanisms of formation and maintenance of muscle contractile apparatus (myofibrils)

肌肉收缩装置（肌原纤维）形成和维持的分子机制

基本信息

批准号：
10304065
负责人：
OBINATA Takashi
金额：
$ 24.02万
依托单位：
CHIBA UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (A)
财政年份：
1998
资助国家：
日本
起止时间：
1998 至 2001
项目状态：
已结题

项目摘要

We examined molecular mechanisms of morphogenesis and maintenance of myofibrils by mainly focussing on cofilin (CF), an actin-binding protein, and C-protein, a myosin- and connectin-bindirig protein. The results are summarized as follow :1.Role of cofilin in myofibrillogenesis1) Excess of CF in muscle cells, which was caused by cDNA transfection or injection of recombinant protein led to disruption of actin filaments and partial disorganization of myofibrils ; 2) In CF-deficient muscle cells, which were generated in mice by gene-manipulation, myofibrillar structures were severely damaged and muscle degeneration was induced in the region where CF-deficient muscle cells were concentrated ; 3) Inactivation of CF by increasing PIP2 in muscle cells also led to insufficient myofibril assembly.Based on these results, we conclude that CF is important not only in myofibril formation but also in maintenance of normal muscle structure.2. Molecular structure and function of C-protein1) Molecular structures of mouse fast skeletal (F) and slow skeletal (S) C-proteins were determined by cDNA technology, and their expression and assembly were clarified and compared with that of cardiac isoform ; 2) Actin-binding domain was specified in N-terminal region of cardiac C-protein ; 3) A novel mouse cardiac C-protein was discovered, which slightly differ in the C-terminal myosin-binding and connectin-binding region and functionally weak. The expression of this variant is up-regulated in aged heart.3. Role of actin-myosin interaction in myofibrillogenesisWe found that BDM (2,3-butanedione 2-monoxime), an inhibitor for myosin ATPase, suppresses, myfibrillogenesis and leads to myofibril disruption and thereby suggested that actin-myosin interaction plays a critical role in the early process of myofibrillogenesis.

我们通过主要专注于肌动蛋白结合蛋白的cofilin（CF）以及肌球蛋白和连接蛋白 - 辛迪里格蛋白的C蛋白，检查了形态发生和肌原纤维的分子机制。结果总结如下：1。肌原纤维生成中cofilin的核能在肌肉细胞中过量的CF过量，这是由cDNA转染或重组蛋白注射引起的，导致肌动蛋白丝的破坏和肌膜纤维的部分混乱。 2）在CF缺乏的肌肉细胞中，通过基因操纵在小鼠中产生的肌肉细胞中，肌原纤维结构严重受损，并在CF缺陷肌肉细胞的区域诱导肌肉变性； 3）CF通过增加肌肉细胞中的PIP2灭活也导致肌原纤维组装不足。基于这些结果，我们得出结论，CF不仅在肌纤维形成中很重要，而且在维持正常的肌肉结构中也很重要。2。 C蛋白1的分子结构和功能）小鼠快速骨骼（F）和慢速骨骼（S）C蛋白的分子结构通过cDNA技术确定，并阐明其表达和组装，并与心脏同工的表达和组装。 2）在心脏C蛋白的N末端区域指定肌动蛋白结合结构域； 3）发现了一种新型的小鼠心脏C蛋白，该心脏C蛋白在C末端肌球蛋白结合和连接蛋白结合区域略有不同，并且在功能上较弱。这种变体的表达在老化的心脏中被上调3。肌动蛋白 - 肌球蛋白相互作用在肌原纤维生成中的作用发现，BDM（2,3-丁烷2-二氧化氢）是肌球蛋白ATPase的抑制剂，抑制，纤维纤维生成并导致肌能纤维中断，从而导致肌动蛋白 - 肌蛋白互动在早期的过程中起着至关重要的作用。