Center for Cell Biology and Cancer Research, Albany Medical College, Albany, New York, USA.
PLoS One. 2012;7(7):e40182. doi: 10.1371/journal.pone.0040182. Epub 2012 Jul 2.
Calcium, a ubiquitous intracellular signaling molecule, controls a diverse array of cellular processes. Consequently, cells have developed strategies to modulate the shape of calcium signals in space and time. The force generating machinery in muscle is regulated by the influx and efflux of calcium ions into the muscle cytoplasm. In order for efficient and effective muscle contraction to occur, calcium needs to be rapidly, accurately and reliably regulated. The mechanisms underlying this highly regulated process are not fully understood. Here, we show that the Caenorhabditis elegans homolog of the giant muscle protein obscurin, UNC-89, is required for normal muscle cell architecture. The large immunoglobulin domain-rich isoforms of UNC-89 are critical for sarcomere and sarcoplasmic reticulum organization. Furthermore, we have found evidence that this structural organization is crucial for excitation-contraction coupling in the body wall muscle, through the coordination of calcium signaling. Thus, our data implicates UNC-89 in maintaining muscle cell architecture and that this precise organization is essential for optimal calcium mobilization and efficient and effective muscle contraction.
钙是一种普遍存在于细胞内的信号分子，控制着多种细胞过程。因此，细胞已经发展出了在空间和时间上调节钙信号形状的策略。肌肉中的力生成机制受钙离子流入和流出肌肉细胞质的调节。为了实现高效和有效的肌肉收缩，钙需要被快速、准确和可靠地调节。这一高度调节过程的机制尚不完全清楚。在这里，我们表明，秀丽隐杆线虫巨型肌肉蛋白 obscurin 的同源物 UNC-89 对于正常的肌肉细胞结构是必需的。UNC-89 的大免疫球蛋白结构域丰富的同工型对于肌节和肌浆网的组织至关重要。此外，我们已经发现证据表明，这种结构组织对于体壁肌肉的兴奋-收缩偶联至关重要，通过钙信号的协调。因此，我们的数据表明 UNC-89 参与维持肌肉细胞的结构，而这种精确的组织对于最佳的钙动员以及高效和有效的肌肉收缩是必不可少的。
