Nap1-mediated actin remodeling is essential for mammalian myoblast fusion
Nap1-mediated actin remodeling is essential for mammalian myoblast fusion
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DOI：
10.1242/jcs.047597
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发表时间：
2009-09-15
影响因子：
4
通讯作者：
Baylies, Mary K.
中科院分区：
文献类型：
--
作者：
Nowak, Scott J.;Nahirney, Patrick C.;Baylies, Mary K.
成肌细胞融合对于健康骨骼肌的形成、生长、维持和再生至关重要。不幸的是，分子机制，细胞行为，膜和细胞骨架重塑事件，管理融合和肌纤维形成仍然知之甚少。使用时间推移成像方法对小鼠C2 C12成肌细胞，我们确定离散和特定的分子事件在成肌细胞膜融合和肌管形成。这些事件包括细胞形状从成纤维细胞到纺锤形形态的重排，在分化的不同时期板状伪足和丝状伪足延伸的变化，以及融合过程中膜排列和组织的变化。我们发现，肌动蛋白细胞骨架重塑是至关重要的，这些事件：药理学抑制F-肌动蛋白聚合导致减少板状和丝状伪足的扩展和减少成肌细胞融合。此外，shRNA介导的抑制Nap 1（WAVE肌动蛋白重塑复合物的成员）导致F-肌动蛋白结构在质膜上的积累，这伴随着成肌细胞融合的减少。我们的数据突出了肌动蛋白细胞骨架重塑在哺乳动物成肌细胞融合过程中的独特和重要的作用，提供了一个平台，融合过程的细胞和分子解剖，并建议在哺乳动物和果蝇之间的成肌细胞融合的Nap 1调节肌动蛋白细胞骨架重塑的功能保护。
Myoblast fusion is crucial for the formation, growth, maintenance and regeneration of healthy skeletal muscle. Unfortunately, the molecular machinery, cell behaviors, and membrane and cytoskeletal remodeling events that govern fusion and myofiber formation remain poorly understood. Using time-lapse imaging approaches on mouse C2C12 myoblasts, we identify discrete and specific molecular events at myoblast membranes during fusion and myotube formation. These events include rearrangement of cell shape from fibroblast to spindle-like morphologies, changes in lamellipodial and filopodial extensions during different periods of differentiation, and changes in membrane alignment and organization during fusion. We find that actin-cytoskeleton remodeling is crucial for these events: pharmacological inhibition of F-actin polymerization leads to decreased lamellipodial and filopodial extensions and to reduced myoblast fusion. Additionally, shRNA-mediated inhibition of Nap1, a member of the WAVE actin-remodeling complex, results in accumulations of F-actin structures at the plasma membrane that are concomitant with a decrease in myoblast fusion. Our data highlight distinct and essential roles for actin cytoskeleton remodeling during mammalian myoblast fusion, provide a platform for cellular and molecular dissection of the fusion process, and suggest a functional conservation of Nap1-regulated actin-cytoskeleton remodeling during myoblast fusion between mammals and Drosophila.