Rab4 regulates formation of synaptic-like microvesicles from early endosomes in PC12 cells
Rab4 regulates formation of synaptic-like microvesicles from early endosomes in PC12 cells
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DOI：
10.1091/mbc.12.11.3703
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发表时间：
2001-11-01
影响因子：
3.3
通讯作者：
van der Sluijs, P
中科院分区：
文献类型：
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作者：
de Wit, H;Lichtenstein, Y;van der Sluijs, P
PC12细胞中的早期内体是形成突触样微泡和组成性循环囊泡的重要位点。通过免疫金电子显微镜观察，小GTPase rab4定位于PC12细胞的早期内体以及细胞外周和高尔基体区域的大量小囊泡。 GTP酶缺陷的Q67Lrab4的过表达增加了早期内体相关囊泡和细胞质囊泡的数量，而GDP结合的S22Nrab4的表达显着增加了早期内体小管的长度。与此同时，Q67Lrab4 诱导 rab4、VAMP2 和 TfR 标记从早期内体转移到外周囊泡，而 S22Nrab4 增加了所有三种蛋白质的早期内体标记。这些观察结果得到了早期内体出芽测定的证实。总之，我们的数据记录了 rab4 在突触样微泡形成中迄今为止未被认识的作用，并增加了我们对早期内体组成型循环囊泡形成的理解。
Early endosomes in PC12 cells are an important site for the formation of synaptic-like microvesicles and constitutive recycling vesicles. By immunogold electron microscopy, the small GTPase rab4 was localized to early endosomes and numerous small vesicles in the cell periphery and Golgi area of PC12 cells. Overexpression of GTPase-deficient Q67Lrab4 increased the number of early endosome-associated and cytoplasmic vesicles, whereas expression of GDP-bound S22Nrab4 significantly increased the length of early endosomal tubules. In parallel, Q67Lrab4 induced a shift in rab4, VAMP2, and TfR label from early endosomes to peripheral vesicles, whereas S22Nrab4 increased early endosome labeling of all three proteins. These observations were corroborated by early endosome budding assays. Together, our data document a thus far unrecognized role for rab4 in the formation of synaptic-like microvesicles and add to our understanding of the formation of constitutive recycling vesicles from early endosomes.