The role of myosin-II in force generation of DRG filopodia and lamellipodia.
The role of myosin-II in force generation of DRG filopodia and lamellipodia.
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DOI：
10.1038/srep07842
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发表时间：
2015-01-19
影响因子：
4.6
通讯作者：
Torre V
中科院分区：
文献类型：
--
作者：
Sayyad WA;Amin L;Fabris P;Ercolini E;Torre V
分化神经元通过板状足和丝状足施加突出力来处理机械刺激。采用光学镊子、视频成像和免疫细胞化学方法，分析了非肌球蛋白- ii对离体背根神经节（Dorsal Root Ganglia， DRG）神经元发育中的生长锥（growth cones, GCs）施加板足和丝足突出力的影响。当30 μM Blebbistatin抑制myosin-II活性时，板足的伸、缩回周期减慢，且在缩回过程中板足不能像对照组那样轴向抬起。25 nM的Cytochalasin-D抑制肌动蛋白聚合和500 nM的Nocodazole抑制微管聚合减慢了板足的伸/缩回周期，但只有Cytochalasin-D抑制了板足的轴向运动。Blebbistatin治疗后，板足所施加的力下降了50%，但令人惊讶的是，丝状足所施加的力增加了20-50%。Nocodazole引起的微管破坏消除了Blebbistatin治疗的丝状足所施加的力的增加。这些结果表明；i- Myosin-II控制板足和丝足施加的力；Ii -由肌动蛋白和肌动蛋白组成的肌动球蛋白复合体的收缩在皱褶的形成中起积极作用；肌球蛋白ii是GCs结构稳定性的重要组成部分。
Differentiating neurons process the mechanical stimulus by exerting the protrusive forces through lamellipodia and filopodia. We used optical tweezers, video imaging and immunocytochemistry to analyze the role of non-muscle myosin-II on the protrusive force exerted by lamellipodia and filopodia from developing growth cones (GCs) of isolated Dorsal Root Ganglia (DRG) neurons. When the activity of myosin-II was inhibited by 30 μM Blebbistatin protrusion/retraction cycles of lamellipodia slowed down and during retraction lamellipodia could not lift up axially as in control condition. Inhibition of actin polymerization with 25 nM Cytochalasin-D and of microtubule polymerization with 500 nM Nocodazole slowed down the protrusion/retraction cycles, but only Cytochalasin-D decreased lamellipodia axial motion. The force exerted by lamellipodia treated with Blebbistatin decreased by 50%, but, surprisingly, the force exerted by filopodia increased by 20-50%. The concomitant disruption of microtubules caused by Nocodazole abolished the increase of the force exerted by filopodia treated with Blebbistatin. These results suggest that; i- Myosin-II controls the force exerted by lamellipodia and filopodia; ii- contractions of the actomyosin complex formed by filaments of actin and myosin have an active role in ruffle formation; iii- myosin-II is an essential component of the structural stability of GCs architecture.