Dimerisation of myomesin:: Implications for the structure of the sarcomeric M-band
Dimerisation of myomesin:: Implications for the structure of the sarcomeric M-band
复制标题
DOI：
10.1016/j.jmb.2004.10.040
复制
发表时间：
2005-01-14
影响因子：
5.6
通讯作者：
Ehler, E
中科院分区：
文献类型：
--
作者：
Lange, S;Himmel, M;Ehler, E
肌节 M 带被认为在粗细丝系统和弹性细丝系统之间提供了联系。到目前为止，人们对其结构组件及其三维组织知之甚少。肌中蛋白似乎是 M 带的重要组成部分，因为它在所研究的所有类型的脊椎动物横纹肌纤维中表达，并且在第一个肌原纤维组装后就可以在其成熟的定位模式中找到。先前的研究表明，肌球蛋白的 N 末端和中心部分含有肌球蛋白、肌联蛋白和肌肉肌酸激酶的结合位点。出于对 C 端半部高度保守的结构域布局的兴趣，我们通过酵母双杂交分析筛选了新的相互作用伙伴。这揭示了肌球蛋白与其自身的强烈相互作用。这一发现得到了多项生化检测的证实。我们的数据表明，肌球蛋白可以通过位于其 C 端结构域 13 中的结合位点形成反向平行二聚体。我们认为，与 Z 盘中的 α-辅肌动蛋白类似，肌球蛋白二聚体与 M 带中的收缩丝交联。新的和先前已确定的肌球蛋白相互作用位点在分子基础上被整合到肌节 M 带的第一个三维模型中。 (C) 2004 Elsevier Ltd. 保留所有权利。
The sarcomeric M-band is thought to provide a link between the thick and the elastic, filament systems. So far, relatively little is known about its structural components and their three-dimensional organisation. Myomesin seems to be an essential component of the M-band, since it is expressed in all types of vertebrate striated muscle fibres investigated and can be found in its mature localisation pattern as soon as the first myofibrils are assembled. Previous work has shown that the N-terminal and central part of myomesin harbour binding sites for myosin, titin and muscle creatine kinase. Intrigued by the highly conserved domain layout of the C-terminal half, we screened for new interaction partners by yeast two-hybrid analysis. This revealed a strong interaction of myomesin with itself. This finding was confirmed by several biochemical assays. Our data suggest that myomesin can form antiparallel dimers via a binding site residing in its C-terminal domain 13. We suggest that, similar to alpha-actinin in the Z-disc, the myomesin dimers cross-link the contractile filaments in the M-band. The new and the already previously identified myomesin interaction sites are integrated into the first three-dimensional model of the sarcomeric M-band on a molecular basis. (C) 2004 Elsevier Ltd. All rights reserved.