Myosin regulatory light chains are required to maintain the stability of myosin II and cellular integrity
Myosin regulatory light chains are required to maintain the stability of myosin II and cellular integrity
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DOI：
10.1042/bj20101473
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发表时间：
2011-02-15
影响因子：
4.1
通讯作者：
Cho, Chunghee
中科院分区：
文献类型：
--
作者：
Park, Inju;Han, Cecil;Cho, Chunghee
Myosin II是一种。肌动蛋白结合蛋白，由MHC（肌球蛋白重链）his、RLC（调节轻链）和ELC（必需轻链）组成。在非肌肉组织中表达的肌球蛋白II在细胞粘附、迁移和分裂中起着核心作用。已知肌球蛋白II活性的调节涉及RLCs的磷酸化，其增加MHCus的Me 2 +-ATP酶活性。然而，鲜为人知的是RLC-MHC II相互作用的细节或哺乳动物细胞中的非肌肉RLCs的功能丧失表型。本论文研究了三种高度保守的小鼠非肌肉类RLC：MYL（myosin light chain）12 A（简称MYL 12 A）、MYL 12 B和MYL 9（MYL 12 A/12 B/9）。蛋白质组学分析表明，所有这三个都与NIH 3 T3成纤维细胞中的MHC MYH 9（NMHC IIA）和MYH 10（NMHC IIB）以及ELC MYL 6相关。我们发现NIH 3 T3细胞中MYL 12 A/12 B的敲除导致细胞形态和动力学发生显着变化。值得注意的是，MYH 9、MYH 10和MYL 6的水平在敲低成纤维细胞中显著降低。全面的相互作用分析揭示，MYL 12 A，MYL 12 B和MYL 9都可以在不同的细胞和组织类型中与各种MHC II相互作用，但与非肌肉类型的MHC II的相互作用最佳。总之，我们的研究提供了直接的证据表明，正常水平的非肌肉RLC是必不可少的维持肌球蛋白II的完整性，并表明RLC是细胞结构和动力学的关键。
Myosin II is an. actin-binding protein composed of MHC (myosin heavy chain) his, RLCs (regulatory light chains) and ELCs (essential light chains). Myosin II expressed in non-muscle tissues plays a central role in cell adhesion, migration and division. The regulation of myosin II activity is known to involve the phosphorylation of RLCs, which increases the Me2+-ATPase activity of MHC us. However, less is known about the details of RLC-MHC II interaction or the loss-of-function phenotypes of non-muscle RLCs in mammalian cells. In the present paper, we investigate three highly conserved non-muscle RLCs of the mouse: MYL (myosin light chain) 12A (referred to as MYL12A), MYL12B and MYL9 (MYL12A/12B/9). Proteomic analysis showed that all three are associated with the MHCs MYH9 (NMHC IIA) and MYH10 (NMHC IIB), as well as the ELC MYL6, in NIH 3T3 fibroblasts. We found that knockdown of MYL12A/12B in NIH 3T3 cells results in striking changes in cell morphology and dynamics. Remarkably, the levels of MYH9, MYH10 and MYL6 were reduced significantly in knockdown fibroblasts. Comprehensive interaction analysis disclosed that MYL12A, MYL12B and MYL9 can all interact with a variety of MHC IIs in diverse cell and tissue types, but do so optimally with non-muscle types of MHC II. Taken together, our study provides direct evidence that normal levels of non-muscle RLCs are essential for maintaining the integrity of myosin II, and indicates that the RLCs are critical for cell structure and dynamics.