Coordinated interaction of Down syndrome cell adhesion molecule and deleted in colorectal cancer with dynamic TUBB3 mediates Netrin-1-induced axon branching.
Coordinated interaction of Down syndrome cell adhesion molecule and deleted in colorectal cancer with dynamic TUBB3 mediates Netrin-1-induced axon branching.
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DOI：
10.1016/j.neuroscience.2015.02.042
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发表时间：
2015-05-07
期刊：
影响因子：
3.3
通讯作者：
Liu G
中科院分区：
文献类型：
--
作者：
Huang H;Shao Q;Qu C;Yang T;Dwyer T;Liu G
神经元中肌动蛋白和微管（MT）动力学的调节与导向信号依赖的轴突生长、分支和路径寻找有关。尽管微管在轴突导向中的作用已广为人知，但细胞外导向信号如何在轴突分支过程中影响微管行为仍不清楚。此前，我们已表明，TUBB3（神经元中最具动态性的β - 微管蛋白亚型）直接与DCC结合，以调节Netrin - 1介导的轴突导向中的微管动力学。在此，我们报告TUBB3直接与另一种Netrin - 1受体DSCAM相互作用，且在原代神经元中Netrin - 1增强了这种相互作用。Netrin - 1促进DSCAM与TUBB3的结合需要微管动力学。敲低DSCAM或DCC，或添加功能阻断性抗DCC抗体，均可相互阻断Netrin - 1诱导的相互作用，这表明在Netrin - 1诱导的与TUBB3的结合过程中，DSCAM与DCC相互依赖地协同作用。在原代神经元的轴突分支和轴突分支点，DSCAM和DCC均与TUBB3部分共定位，且Netrin - 1增强了这些共定位。在原代神经元中，Netrin - 1诱导内源性DSCAM与聚合的TUBB3相互作用，且Src家族激酶（SFKs）是调节这种结合所必需的。单独敲低DSCAM、单独敲低DCC或同时敲低两者，都足以阻断Netrin - 1诱导的E15小鼠皮层神经元轴突分支。敲低TUBB3也会抑制Netrin - 1诱导的轴突分支。这些结果表明，在Netrin - 1诱导的轴突分支过程中，DSCAM与DCC协作，通过直接结合动态的TUBB3来调节微管动力学。
Modulation of actin and microtubule (MT) dynamics in neurons is implicated in guidance cue-dependent axon outgrowth, branching and pathfinding. Although the role of MTs in axon guidance has been well known, how extracellular guidance signals engage MT behavior in axon branching remains unclear. Previously, we have shown that TUBB3, the most dynamic β-tubulin isoform in neurons, directly binds to DCC to regulate MT dynamics in Netrin-1-mediated axon guidance. Here, we report that TUBB3 directly interacted with another Netrin-1 receptor DSCAM and Netrin-1 increased this interaction in primary neurons. MT dynamics were required for Netrin-1-promoted association of DSCAM with TUBB3. Knockdown of either DSCAM or DCC or addition of a function blocking anti-DCC antibody mutually blocked Netrin-1-induced interactions, suggesting that DSCAM interdependently coordinated with DCC in Netrin-1-induced binding to TUBB3. Both DSCAM and DCC were partially colocalized with TUBB3 in the axon branch and the axon branching point of primary neurons and Netrin-1 increased these colocalizations. Netrin-1 induced the interaction of endogenous DSCAM with polymerized TUBB3 in primary neurons and Src family kinases (SFKs) were required for regulating this binding. Knockdown of DSCAM only, DCC only or both was sufficient to block Netrin-1-induced axon branching of E15 mouse cortical neurons. Knocking down TUBB3 inhibited Netrin-1 induced axon branching as well. These results suggest that DSCAM collaborates with DCC to regulate MT dynamics via direct binding to dynamic TUBB3 in Netrin-1-induced axon branching.