SALS, a WH2-domain-containing protein, promotes sarcomeric actin filament elongation from pointed ends during Drosophila muscle growth
SALS, a WH2-domain-containing protein, promotes sarcomeric actin filament elongation from pointed ends during Drosophila muscle growth
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DOI：
10.1016/j.devcel.2007.10.003
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发表时间：
2007-12-01
影响因子：
11.8
通讯作者：
Perrimon, Norbert
中科院分区：
文献类型：
--
作者：
Bai, Jianwu;Hartwig, John H.;Perrimon, Norbert
肌动蛋白丝组织成一个组织良好的肌节结构是肌肉发育和功能的关键。然而，目前还不完全清楚肌节肌动蛋白/细丝是如何达到其定型长度的。在果蝇原代肌细胞的RNAi筛选中，我们确定了一个基因，肌节长度短（sals），它编码一个肌动蛋白结合，WH 2结构域的蛋白质，需要适当的肌节大小。当sals被RNAi敲低时，初级肌肉显示出薄的肌原纤维，肌节缩短，肌节数量增加。功能丧失和功能获得的分析表明，SAILS可能会影响肌节长度，促进细丝延长从尖端。此外，SAILS和其他肌节蛋白在肌原纤维中的复杂定位揭示了细丝的全长是在两步过程中实现的，并且SALS是第二伸长阶段所需的，最有可能是因为它拮抗尖端加帽蛋白Tropomodulin。
Organization of actin filaments into a well-organized sarcomere structure is critical for muscle development and function. However, it is not completely understood how sarcomeric actin/thin filaments attain their stereotyped lengths. In an RNAi screen in Drosophila primary muscle cells, we identified a gene, sarcomere length short (sals), which encodes an actin-binding, WH2 domain-containing protein, required for proper sarcomere size. When sals is knocked down by RNAi, primary muscles display thin myofibrils with shortened sarcomeres and increased sarcomere number. Both loss- and gain-of-function analyses indicate that SAILS may influence sarcomere lengths by promoting thin-filament lengthening from pointed ends. Furthermore, the complex localization of SAILS and other sarcomeric proteins in myofibrils reveals that the full length of thin filaments is achieved in a two-step process, and that SALS is required for the second elongation phase, most likely because it antagonizes the pointed-end capping protein Tropomodulin.