Differential roles of kinesin and dynein in translocation of neurofilaments into axonal neurites
Differential roles of kinesin and dynein in translocation of neurofilaments into axonal neurites
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DOI：
10.1242/jcs.079046
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发表时间：
2011-04-01
影响因子：
4
通讯作者：
Shea, Thomas B.
中科院分区：
文献类型：
--
作者：
Lee, Sangmook;Sunil, Neethu;Shea, Thomas B.
神经丝(NF)亚单位在轴突内以短的神经丝、非丝状点状结构(点状)和可能包含单个亚单位和/或低聚物的弥漫性物质的形式转移。神经纤维进入轴突和沿轴突的运输是由微管(MT)运动蛋白、动蛋白和动力蛋白调节的。尽管Dynein具有逆行运动的特征，但它通过与长的MTS或肌动蛋白皮质通过其货物结构域结合而参与了顺行的NF运输；与运动域相关的相对较短的MTS随后与任何相连的Nf一起被推向顺行方向。在这里，我们发现，通过动态蛋白的过度表达或抗动力蛋白抗体的细胞内传递，动力蛋白功能的抑制选择性地减少了GFP标记的短神经纤维进入轴突的传递，而相应地增加了斑点的传递，这表明动力蛋白选择性地将短神经传递到轴突中。诺可达唑介导的短MTS耗竭也有同样的效果。相反，细胞内传递的抗动蛋白抗体在同等程度上抑制了短纤维和点状纤维的顺行运输。这些发现表明，线状神经纤维的顺行轴突运输比神经纤维点或寡聚体的运输更依赖于MT的移位(它们本身是由动力蛋白移位的)。
Neurofilament (NF) subunits translocate within axons as short NFs, non-filamentous punctate structures ('puncta') and diffuse material that might comprise individual subunits and/or oligomers. Transport of NFs into and along axons is mediated by the microtubule (MT) motor proteins kinesin and dynein. Despite being characterized as a retrograde motor, dynein nevertheless participates in anterograde NF transport through associating with long MTs or the actin cortex through its cargo domain; relatively shorter MTs associated with the motor domain are then propelled in an anterograde direction, along with any linked NFs. Here, we show that inhibition of dynein function, through dynamitin overexpression or intracellular delivery of anti-dynein antibody, selectively reduced delivery of GFP-tagged short NFs into the axonal hillock, with a corresponding increase in the delivery of puncta, suggesting that dynein selectively delivered short NFs into axonal neurites. Nocodazole-mediated depletion of short MTs had the same effect. By contrast, intracellular delivery of anti-kinesin antibody inhibited anterograde transport of short NFs and puncta to an equal extent. These findings suggest that anterograde axonal transport of linear NFs is more dependent upon association with translocating MTs (which are themselves translocated by dynein) than is transport of NF puncta or oligomers.