zipper nonmuscle myosin-II functions downstream of PS2 integrin in Drosophila myogenesis and is necessary for myofibril formation
zipper nonmuscle myosin-II functions downstream of PS2 integrin in Drosophila myogenesis and is necessary for myofibril formation
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DOI：
10.1006/dbio.2001.0452
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发表时间：
2001-11-15
影响因子：
2.7
通讯作者：
Kiehart, DP
中科院分区：
文献类型：
--
作者：
Bloor, JW;Kiehart, DP
非肌肉肌球蛋白-II是驱动细胞形状改变和细胞运动的关键运动蛋白。在这里，我们分析了非肌肉肌球蛋白-II在果蝇胚胎肌发生过程中的功能。我们发现，非肌肉肌球蛋白-II和粘附分子，PS2整合素，共定位在发展中的肌肉末端。在培养的成纤维细胞中出现的范例中，需要由小GTdR Rho介导的非肌肉肌动球蛋白-II收缩性将整合素聚集在焦点粘连处。在这个模型的直接反对，我们发现，无论是非肌肉肌球蛋白-II，也没有RhoA出现在PS2聚类功能。相反，PS2整联蛋白是必需的非肌肉肌球蛋白-II本地化的维护，我们表明，β（PS）整联蛋白亚基的细胞质尾能够介导这PS2整联蛋白的功能。我们发现，胚胎缺乏合子表达的非肌肉肌球蛋白-II不能形成横纹肌原纤维。与此一致，我们证明了特异性破坏肌原纤维形成的PS2突变体无法介导非肌肉肌球蛋白II在肌肉末端的正确定位。相比之下，缺乏RhoA功能的胚胎确实会产生横纹肌。最后，我们发现，nonmuscle myosin-II定位于Z-线在成熟的幼虫肌肉。我们认为，非肌肉肌球蛋白-II的功能在肌肉末端和Z-线作为一个肌动蛋白交联剂，并采取行动，以保持结构完整的肌节。(C)北京：科学出版社.
Nonmuscle myosin-II is a key motor protein that drives cell shape change and cell movement. Here, we analyze the function of nonmuscle myosin-II during Drosophila embryonic myogenesis. We find that nonmuscle myosin-II and the adhesion molecule, PS2 integrin, colocalize at the developing muscle termini. In the paradigm emerging from cultured fibroblasts, nonmuscle actomyosin-II contractility, mediated by the small GTPase Rho, is required to cluster integrins at focal adhesions. In direct opposition to this model, we find that neither nonmuscle myosin-II nor RhoA appear to function in PS2 clustering. Instead, PS2 integrin is required for the maintenance of nonmuscle myosin-II localization and we show that the cytoplasmic tail of the (beta (ps) integrin subunit is capable of mediating this PS2 integrin function. We show that embryos that lack zygotic expression of nonmuscle myosin-II fail to form striated myofibrils. In keeping with this, we demonstrate that a PS2 mutant that specifically disrupts myofibril formation is unable to mediate proper localization of nonmuscle myosin-II at the muscle termini. In contrast, embryos that lack RhoA function do generate striated muscles. Finally, we find that nonmuscle myosin-II localizes to the Z-line in mature larval muscle. We suggest that nonmuscle myosin-II functions at the muscle termini and the Z-line as an actin crosslinker and acts to maintain the structural integrity of the sarcomere. (C) 2001 Academic Press.