Nonmuscle myosin 2 filaments are processive in cells
Nonmuscle myosin 2 filaments are processive in cells
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非肌肉肌球蛋白 2 丝在细胞中持续进行
DOI：
10.1016/j.bpj.2023.05.014
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发表时间：
2023
影响因子：
3.4
通讯作者：
Beach, Jordan R.
中科院分区：
文献类型：
--
作者：
Vitriol, Eric A.;Quintanilla, Melissa A.;Tidei, Joseph J.;Troughton, Lee D.;Cody, Abigail;Cisterna, Bruno A.;Jane, Makenzie L.;Oakes, Patrick W.;Beach, Jordan R.
细胞成分的定向运输通常依赖于细胞骨架马达的进行性运动。肌球蛋白2马达主要接合相反方向的肌动蛋白丝来驱动收缩事件，因此传统上不被视为进行性的。然而，最近的体外实验纯化的非肌肉肌球蛋白2（NM 2）证明肌球蛋白2丝可以向前移动。在这里，我们建立了持续合成能力作为NM 2的细胞特性。在中枢神经系统衍生的CAD细胞中，进行性运行在终止于前缘的突起中的成束肌动蛋白上最明显。我们发现，在体内进行速度与体外测量是一致的。NM 2以其丝状形式对抗板状伪足逆行流动，尽管在没有肌动蛋白动力学的情况下仍然可以发生顺行运动。比较NM 2亚型的持续合成能力，我们发现NM 2A的移动速度略快于NM 2B。最后，我们证明，这不是一个细胞特异性的属性，因为我们观察到的过程样运动的NM 2的板层和亚核应力纤维的成纤维细胞。总的来说，这些观察结果进一步拓宽了NM 2的功能和已经无处不在的马达可以做出贡献的生物过程。
Directed transport of cellular components is often dependent on the processive movements of cytoskeletal motors. Myosin 2 motors predominantly engage actin filaments of opposing orientation to drive contractile events and are therefore not traditionally viewed as processive. However, recent in vitro experiments with purified nonmuscle myosin 2 (NM2) demonstrated myosin 2 filaments could move processively. Here, we establish processivity as a cellular property of NM2. Processive runs in central nervous system-derived CAD cells are most apparent on bundled actin in protrusions that terminate at the leading edge. We find that processive velocities in vivo are consistent with in vitro measurements. NM2 makes these processive runs in its filamentous form against lamellipodia retrograde flow, though anterograde movement can still occur in the absence of actin dynamics. Comparing the processivity of NM2 isoforms, we find that NM2A moves slightly faster than NM2B. Finally, we demonstrate that this is not a cell-specific property, as we observe processive-like movements of NM2 in the lamella and subnuclear stress fibers of fibroblasts. Collectively, these observations further broaden NM2 functionality and the biological processes in which the already ubiquitous motor can contribute.