A deficiency of the small GTPase rab8 inhibits membrane traffic in developing neurons
A deficiency of the small GTPase rab8 inhibits membrane traffic in developing neurons
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小 GTP 酶 rab8 的缺陷会抑制发育中神经元的膜运输
DOI：
10.1128/mcb.15.2.918
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发表时间：
1995
影响因子：
5.3
通讯作者：
Carlos G. Dotti
中科院分区：
文献类型：
--
作者：
Lukas A. Huber;Paul Dupree;Carlos G. Dotti
发育中的神经元的主要活动之一是将新的膜运输到生长中的轴突。在这种密集的交通调节中发挥关键作用的候选蛋白是Rab家族的小GTP结合蛋白。我们利用培养的海马神经元，分析了抑制小GTP结合蛋白Rab8表达后的膜转运活性。通过使用序列特异性反义寡核苷酸来抑制蛋白质的表达。当Rab8缺失导致95%的神经元形态成熟受阻时，另一种Rab蛋白Rab3a的表达抑制不起作用，所有神经元都发育正常的轴突和树突。Rab8反义治疗对神经元成熟度的影响是由于膜转运受阻所致。因此，通过使用视频增强的差示干涉对比显微镜，我们在Rab8耗尽的细胞中观察到经历顺行运输的囊泡数量显著减少。此外，通过将反义处理的神经元与BODIPY标记的神经酰胺孵育，我们观察到荧光标记仅限于高尔基体，而在对照细胞的轴突中也发现了标记。这些结果表明，小GTP酶Rab8在神经元突起生长过程中的膜运输中起着重要作用。
One of the major activities of developing neurons is the transport of new membrane to the growing axon. Candidates for playing a key role in the regulation of this intense traffic are the small GTP-binding proteins of the rab family. We have used hippocampal neurons in culture and analyzed membrane traffic activity after suppressing the expression of the small GTP-binding protein rab8. Inhibition of protein expression was accomplished by using sequence-specific antisense oligonucleotides. While rab8 depletion resulted in the blockage of morphological maturation in 95% of the neurons, suppression of expression of another rab protein, rab3a, had no effect, and all neurons developed normal axons and dendrites. The impairment of neuronal maturation by rab8 antisense treatment was due to inhibition of membrane traffic. Thus, by using video-enhanced differential interference contrast microscopy, we observed in the rab8-depleted cells a dramatic reduction in the number of vesicles undergoing anterograde transport. Moreover, by incubating antisense-treated neurons with Bodipy-labeled ceramide, a fluorescent marker for newly formed exocytic vesicles, we observed fluorescence labeling restricted to the Golgi apparatus, whereas in control cells labeling was found also in the neurites. These results show the role of the small GTPase rab8 in membrane traffic during neuronal process outgrowth.