Myosin Va increases the efficiency of neurofilament transport by decreasing the duration of long-term pauses.
Myosin Va increases the efficiency of neurofilament transport by decreasing the duration of long-term pauses.
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DOI：
10.1523/jneurosci.3829-08.2009
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发表时间：
2009-05-20
期刊：
影响因子：
--
通讯作者：
Brown A
中科院分区：
文献类型：
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作者：
Alami NH;Jung P;Brown A
我们研究了两种不同品系的稀释致死小鼠，缺乏肌球蛋白Va的培养神经元中神经丝的轴突运输。为了分析运动行为，我们追踪了绿色荧光蛋白（GFP）标记的神经丝通过来自DLS/LeJ稀释致死小鼠的培养的上级颈神经节神经元的轴突神经丝阵列中自然存在的间隙的运动。与野生型对照组相比，我们观察到运动速度或频率没有统计学显著差异。为了分析暂停行为，我们使用荧光光活化脉冲逃逸技术来测量来自DLS/LeJ和dl 20 J稀释致死小鼠的培养背根神经节神经元中PAGFP（可光活化GFP）标记的神经丝从光活化轴突节段的离开速率。与野生型对照相比，我们观察到DLS/LeJ小鼠神经元中神经丝离开激活区域的平均时间增加了48%（p<0.001），dl 20 J小鼠神经元中增加了169%（p<0.0001）。这些数据表明，肌球蛋白Va的情况下，神经丝暂停更长的时间。我们假设肌球蛋白Va是神经丝的短程马达，并且它可以通过将神经丝递送到其微管轨道来增强轴突中神经丝运输的效率，从而减少长时间的偏离轨道暂停的持续时间。
We investigated the axonal transport of neurofilaments in cultured neurons from two different strains of dilute lethal mice, which lack myosin Va. To analyze the motile behavior, we tracked the movement of green fluorescent protein (GFP)-tagged neurofilaments through naturally occurring gaps in the axonal neurofilament array of cultured superior cervical ganglion neurons from DLS/LeJ dilute lethal mice. Compared with wild-type controls, we observed no statistically significant difference in velocity or frequency of movement. To analyze the pausing behavior, we used a fluorescence photoactivation pulse– escape technique to measure the rate of departure of PAGFP (photoactivatable GFP)-tagged neurofilaments from photoactivated axonal segments in cultured dorsal root ganglion neurons from DLS/LeJ and dl20J dilute lethal mice. Compared with wild-type controls, we observed a 48% increase in the mean time for neurofilaments to depart the activated regions in neurons from DLS/LeJ mice ( p<0.001) and a 169% increase in neurons from dl20J mice ( p<0.0001). These data indicate that neurofilaments pause for more prolonged periods in the absence of myosin Va. We hypothesize that myosin Va is a short-range motor for neurofilaments and that it can function to enhance the efficiency of neurofilament transport in axons by delivering neurofilaments to their microtubule tracks, thereby reducing the duration of prolonged off-track pauses.