权益分类	功能权益	普通用户	{{item.name}}会员
{{category.name}}	{{benefitItem.name}}

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.

我们研究了肌原纤维的形态发生和维持的分子机制，主要集中在肌动蛋白结合蛋白cofilin （CF）和肌球蛋白和连接蛋白结合蛋白c蛋白上。研究结果总结如下：1。cofilin在肌原纤维形成中的作用1)转染cDNA或注射重组蛋白导致肌肉细胞中CF过量，导致肌动蛋白丝断裂，肌原纤维部分断裂；2)通过基因操作在小鼠体内生成的缺钙肌细胞，在缺钙肌细胞集中的区域，肌原纤维结构严重受损，引起肌肉变性；3)肌细胞中PIP2增加导致CF失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不仅对肌原纤维的形成很重要，而且对正常肌肉结构的维持也很重要。c蛋白的分子结构和功能1)利用cDNA技术测定小鼠快骨骼(F)和慢骨骼(S) c蛋白的分子结构，明确其表达和组装，并与心脏同种异构体进行比较；2)心肌c蛋白n端区存在肌动蛋白结合域；3)发现了一种新的小鼠心脏c蛋白，其c端肌球蛋白结合区和连接蛋白结合区略有不同，功能较弱。该变异在老年心脏中表达上调。肌动蛋白-肌球蛋白相互作用在肌原纤维形成中的作用我们发现，肌动蛋白atp酶抑制剂BDM（2,3-丁二酮2-单肟）抑制肌原纤维形成并导致肌原纤维断裂，因此表明肌动蛋白-肌球蛋白相互作用在肌原纤维形成的早期过程中起关键作用。