Drebrin coordinates the actin and microtubule cytoskeleton during the initiation of axon collateral branches.
Drebrin coordinates the actin and microtubule cytoskeleton during the initiation of axon collateral branches.
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DOI：
10.1002/dneu.22377
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发表时间：
2016-10
影响因子：
3
通讯作者：
Gallo G
中科院分区：
文献类型：
--
作者：
Ketschek A;Spillane M;Dun XP;Hardy H;Chilton J;Gallo G
Drebrin 是一种细胞骨架相关蛋白，可以与肌动蛋白丝和微管尖端相互作用。它的作用主要在树突中进行研究，而轴突中的drebrin 功能还不太清楚。在这项工作中，我们通过shRNA介导的耗竭和过度表达分析了drebrin在鸡胚胎感觉轴突侧支分支中的作用。我们报道drebrin在体内和体外促进轴突丝状伪足和侧支分支的形成。细胞骨架动力学的实时成像显示，drebrin 促进由称为轴突肌动蛋白斑块的前体结构形成丝状伪足。内源性 Drebrin 定位于肌动蛋白斑块，消耗研究表明 Drebrin 有助于斑块的发育。在丝状伪足中，内源性脑蛋白定位于丝状伪足的近端部分。研究发现 Drebrin 可以促进轴突丝状伪足的稳定性以及微管和尖端进入轴突丝状伪足。 drebrin 对丝状伪足稳定的作用与其促进微管靶向丝状伪足的作用无关。肌球蛋白 II 的抑制诱导内源性 Drebrin 向远端重新分布到丝状伪足，并进一步增加过度表达 Drebrin 的神经元的分支。最后，用分支诱导信号神经生长因子进行 30 分钟的治疗会增加轴突 Drebrin 的水平。目前的研究确定了drebrin在轴突细胞骨架调节中的具体作用，并提供了drebrin在轴突分支初始阶段有助于肌动蛋白和微管细胞骨架协调的证据。
Drebrin is a cytoskeleton-associated protein which can interact with both actin filaments and the tips of microtubules. Its roles have been studied mostly in dendrites, and the functions of drebrin in axons are less well understood. In this work we analyzed the role of drebrin, through shRNA-mediated depletion and over-expression, in the collateral branching of chicken embryonic sensory axons. We report that drebrin promotes the formation of axonal filopodia and collateral branches in vivo and in vitro. Live imaging of cytoskeletal dynamics revealed that drebrin promotes the formation of filopodia from precursor structures termed axonal actin patches. Endogenous drebrin localizes to actin patches and depletion studies indicate that drebrin contributes to the development of patches. In filopodia, endogenous drebrin localizes to the proximal portion of the filopodium. Drebrin was found to promote the stability of axonal filopodia and the entry of microtubule plus tips into axonal filopodia. The effects of drebrin on the stabilization of filopodia are independent of its effects on promoting microtubule targeting to filopodia. Inhibition of myosin II induces a redistribution of endogenous drebrin distally into filopodia, and further increases branching in drebrin overexpressing neurons. Finally, a 30 minute treatment with the branch inducing signal nerve growth factor increases the levels of axonal drebrin. The current study determines the specific roles of drebrin in the regulation of the axonal cytoskeleton, and provides evidence that drebrin contributes to the coordination of the actin and microtubule cytoskeleton during the initial stages of axon branching.