THE INVOLVEMENT OF THE SMALL GTP-BINDING PROTEIN RAB5A IN NEURONAL ENDOCYTOSIS
THE INVOLVEMENT OF THE SMALL GTP-BINDING PROTEIN RAB5A IN NEURONAL ENDOCYTOSIS
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DOI：
10.1016/0896-6273(94)90456-1
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发表时间：
1994-07-01
期刊：
影响因子：
16.2
通讯作者：
DOTTI, CG
中科院分区：
文献类型：
--
作者：
DEHOOP, MJ;HUBER, LA;DOTTI, CG
Rab5a 是一种小型 GTP 酶，可调节内吞囊泡与早期内体的融合。我们研究了 Rab5a 是否参与极化神经元轴突和体细胞树突域的早期内吞运输。使用免疫荧光，在轴突和树突中检测到内源性 Rab5a。它在轴突中的定位与突触小泡蛋白突触素的定位强烈重叠。事实上，Rab5a 与含有突触素的囊泡共免疫分离，并且针对 Rab5a 的抗体标记了神经末梢中的突触小泡样结构。在培养的海马神经元中过度表达野生型和突变型 Rab5a 后，通过电子显微镜分析了 Rab5a 与树突和轴突早期内体的功能关联。这诱导了体树突和轴突域中异常内体的形成。这些结果表明 Rab5a 在轴突和树突状内吞作用中的作用，并且 Rab5a 在突触小泡上的存在表明轴突内体参与这些小泡的生物发生。
Rab5a is a small GTPase that regulates fusion of endocytic vesicles to early endosomes. We investigated whether Rab5a is involved in early endocytic traffic in both the axonal and the somatodendritic domains of polarized neurons. Using immunofluorescence, endogenous Rab5a was detected in axons and dendrites. Its localization in axons strongly overlapped that of the synaptic vesicle protein synaptophysin. Indeed, Rab5a coimmunoisolated with synaptophysin-containing vesicles, and antibodies against Rab5a labeled synaptic vesicle-like structures in nerve terminals, The functional association of Rab5a with dendritic and axonal early endosomes was assayed by electron microscopy after overexpression of wild-type and mutant Rab5a in cultured hippocampal neurons. This induced the formation of abnormal endosomes in both the somatodendritic and the axonal domains. These results show a role for Rab5a in axonal and dendritic endocytosis, and the presence of Rab5a on synaptic vesicles indicates that the axonal endosomes participate in the biogenesis of these vesicles.