The nebulette repeat domain is necessary for proper maintenance of tropomyosin with the cardiac sarcomere
The nebulette repeat domain is necessary for proper maintenance of tropomyosin with the cardiac sarcomere
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DOI：
10.1016/j.yexcr.2008.09.001
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发表时间：
2008-11-15
影响因子：
3.7
通讯作者：
Moncman, Carole L.
中科院分区：
文献类型：
--
作者：
Bonzo, Jeremy R.;Norris, Andrea A.;Moncman, Carole L.
Nebulette 是巨型肌动蛋白结合蛋白 Nebulin 的心脏 iac 特异性亚型。星云的质量接近 100 kDa，预计仅从 Z 线边缘延伸 150 nm。鸡心肌细胞中云状 C 端接头和/或 SH3 结构域的过度表达会导致内源性云状的损失，并伴随原肌球蛋白 (TPM) 和肌钙蛋白的损失，以及细丝的缩短。这些数据表明，星云在肌节中的位置对于维持 TPM、肌钙蛋白和细丝长度很重要。为了评估这一假设，在鸡心肌细胞中表达了带有 GFP 标记的 N 端嵌套截断，并分析了细胞的肌丝蛋白分布。 N 端删除最多 10 个模块时观察到对肌丝的影响最小：然而，删除 15 个模块复制了 C 端片段表达中观察到的表型。星云内部缺失的表达证实模块 10 和 15 之间的位点对于肌节晶格内 TPM 的维持很重要。我们还从酵母二杂种 (Y2H) 分析中分离出 TPM cDNA。这些数据表明了星云-TPM 相互作用对于细丝的维持和稳定性的重要性。 (C) 2008 Elsevier Inc. 保留所有权利。
Nebulette is a card iac-specific isoform of the giant actin-binding protein nebulin. Nebulette, having a mass of similar to 100 kDa, is only predicted to extend 150 nm from the edge of the Z-lines. Overexpression of the nebulette C-terminal linker and/or SH3 domains in chicken cardiomyocytes results in a loss of endogenous nebulette with a concomitant loss of tropomyosin (TPM) and troponin, as well as a shortening of the thin filaments. These data suggest that nebulette's position in the sarcomere is important for the maintenance of TPM, troponin and thin filament length. To evaluate this hypothesis, N-terminal nested truncations tagged with GFP were expressed in chicken cardiomyocytes and the cells were analyzed for the distribution of myofilament proteins. Minimal effects on the myofilaments were observed with N-terminal deletions of up to 10 modules: however, deletion of 15 modules replicated the phenotype observed with expression of the C-terminal fragments. Expression of internal deletions of nebulette verifies that a site between module 10 and 15 is important for TPM maintenance within the sarcomeric lattice. We have additionally isolated TPM cDNAs from a yeast two hybrid (Y2H) analysis. These data indicate the importance of the nebulette-TPM interactions in the maintenance and stability of the thin filaments. (C) 2008 Elsevier Inc. All rights reserved.