Arf6 Guanine Nucleotide Exchange Factor Cytohesin-2 Binds to CCDC120 and Is Transported Along Neurites to Mediate Neurite Growth*
Arf6 Guanine Nucleotide Exchange Factor Cytohesin-2 Binds to CCDC120 and Is Transported Along Neurites to Mediate Neurite Growth*
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DOI：
10.1074/jbc.m114.575787
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发表时间：
2014-10
期刊：
影响因子：
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通讯作者：
Tomohiro Torii;Y. Miyamoto;K. Tago;K. Sango;Kazuaki Nakamura;A. Sanbe;A. Tanoue;J. Yamauchi
中科院分区：
文献类型：
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作者：
Tomohiro Torii;Y. Miyamoto;K. Tago;K. Sango;Kazuaki Nakamura;A. Sanbe;A. Tanoue;J. Yamauchi
背景：Arf6 激活剂 cytohesin-2 参与神经突生长。结果：Cytohesin-2 与 CCDC120 结合并沿着生长的神经突运输。结论：这种相互作用是 Arf6 激活和神经突生长所必需的。意义：以前未知的功能性 CCDC120 是一种新的细胞粘连蛋白，可调节神经突生长。神经突生长的机制很复杂，涉及持续的细胞骨架重排和囊泡运输。 Cytohesin-2 是 Arf6（一种 Arf 家族分子开关蛋白）的鸟嘌呤核苷酸交换因子，控制细胞形态变化，例如神经突发生。在这里，我们展示了 cytohesin-2 与一种具有先前未知功能的蛋白质 CCDC120 结合，该蛋白质包含三个卷曲螺旋结构域，并在分化的 N1E-115 细胞中沿着神经突转运。将 CCDC120 特异性的小干扰 RNA (siRNA) 转染至细胞中可抑制神经突生长和 Arf6 激活。当神经突开始延伸时，含有 CCDC120 和 cytohesin-2 的囊泡以顺行方式而不是逆行方式运输。随着神经突继续延伸，顺行囊泡运输减少。 CCDC120 敲低抑制细胞粘附素 2 定位到含有 CCDC120 的囊泡中，并使细胞粘附素 2 扩散到细胞质区域，这说明 CCDC120 决定了生长中的神经突中细胞粘附素 2 的定位。将野生型 CCDC120 构建体重新引入用 CCDC120 siRNA 转染的细胞中可逆转减弱的神经突生长和 Arf6 活性，而结合细胞粘附素 2 的 CC1 区域缺陷的 CCDC120 构建体则不会。因此，细胞粘附素-2 通过含有 CCDC120 的囊泡沿着神经突运输，并介导神经突生长。这些结果表明了 Arf6 的鸟嘌呤核苷酸交换因子被转运以介导神经突生长的机制。
Background: The Arf6 activator, cytohesin-2, is involved in neurite growth. Results: Cytohesin-2 binds to CCDC120 and is transported along growing neurites. Conclusion: This interaction is required for Arf6 activation and neurite growth. Significance: The previously unknown functional CCDC120 is a new cytohesin adaptor protein, which regulates neurite growth. The mechanism of neurite growth is complicated, involving continuous cytoskeletal rearrangement and vesicular trafficking. Cytohesin-2 is a guanine nucleotide exchange factor for Arf6, an Arf family molecular switch protein, controlling cell morphological changes such as neuritogenesis. Here, we show that cytohesin-2 binds to a protein with a previously unknown function, CCDC120, which contains three coiled-coil domains, and is transported along neurites in differentiating N1E-115 cells. Transfection of the small interfering RNA (siRNA) specific for CCDC120 into cells inhibits neurite growth and Arf6 activation. When neurites start to extend, vesicles containing CCDC120 and cytohesin-2 are transported in an anterograde manner rather than a retrograde one. As neurites continue extension, anterograde vesicle transport decreases. CCDC120 knockdown inhibits cytohesin-2 localization into vesicles containing CCDC120 and diffuses cytohesin-2 in cytoplasmic regions, illustrating that CCDC120 determines cytohesin-2 localization in growing neurites. Reintroduction of the wild type CCDC120 construct into cells transfected with CCDC120 siRNA reverses blunted neurite growth and Arf6 activity, whereas the cytohesin-2-binding CC1 region-deficient CCDC120 construct does not. Thus, cytohesin-2 is transported along neurites by vesicles containing CCDC120, and it mediates neurite growth. These results suggest a mechanism by which guanine nucleotide exchange factor for Arf6 is transported to mediate neurite growth.