BFA-induced compartments from the Golgi apparatus and trans-Golgi network/early endosome are distinct in plant cells
BFA-induced compartments from the Golgi apparatus and trans-Golgi network/early endosome are distinct in plant cells
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DOI：
10.1111/j.1365-313x.2009.04007.x
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发表时间：
2009-12-01
期刊：
影响因子：
7.2
通讯作者：
Jiang, Liwen
中科院分区：
文献类型：
--
作者：
Lam, Sheung Kwan;Cai, Yi;Jiang, Liwen
P> Brefeldin A (BFA) 是研究蛋白质运输和识别植物分泌和内吞途径中细胞器的有用工具。在低浓度（5-10 mu g ml-1）下，BFA 会导致高尔基体和反式高尔基体网络 (TGN)（植物细胞中的早期内体 (EE) 等效物）在转基因烟草 BY-2 细胞中形成可见的聚集体。在这里，我们表明，这些来自高尔基体和 TGN 的 BFA 诱导的聚集体在植物细胞中在形态和功能上是不同的。共聚焦免疫荧光和免疫金电子显微镜 (EM) 研究表明，BFA 诱导的高尔基体和 TGN 衍生的聚集体在物理上彼此不同。此外，内化的内体标记 FM4-64 与 TGN 衍生的聚集体共定位，但不与高尔基体聚集体共定位。在以剂量和时间依赖性方式起作用的内吞抑制剂酪氨酸磷酸化蛋白 A23 存在的情况下，SCAMP1（分泌载体膜蛋白 1）和 FM4-64 大多被排除在 SYP61 阳性 BFA 诱导的 TGN 聚集体之外，表明 TGN 的同型融合而不是从头内吞运输对于 TGN/EE 衍生的 BFA 诱导的聚集体的形成很重要。由于 TGN 还充当 EE，不断从质膜接收物质，因此我们的数据支持这样的观点，即分泌型高尔基体细胞器在植物细胞中对 BFA 处理的反应方面与内吞型 TGN/EE 不同。因此，高尔基体和 TGN 可能是植物中功能不同的细胞器。
P>Brefeldin A (BFA) is a useful tool for studying protein trafficking and identifying organelles in the plant secretory and endocytic pathways. At low concentrations (5-10 mu g ml-1), BFA caused both the Golgi apparatus and trans-Golgi network (TGN), an early endosome (EE) equivalent in plant cells, to form visible aggregates in transgenic tobacco BY-2 cells. Here we show that these BFA-induced aggregates from the Golgi apparatus and TGN are morphologically and functionally distinct in plant cells. Confocal immunofluorescent and immunogold electron microscope (EM) studies demonstrated that BFA-induced Golgi- and TGN-derived aggregates are physically distinct from each other. In addition, the internalized endosomal marker FM4-64 co-localized with the TGN-derived aggregates but not with the Golgi aggregates. In the presence of the endocytosis inhibitor tyrphostin A23, which acts in a dose- and time-dependent manner, SCAMP1 (secretory carrier membrane protein 1) and FM4-64 are mostly excluded from the SYP61-positive BFA-induced TGN aggregates, indicating that homotypic fusion of the TGN rather than de novo endocytic trafficking is important for the formation of TGN/EE-derived BFA-induced aggregates. As the TGN also serves as an EE, continuously receiving materials from the plasma membrane, our data support the notion that the secretory Golgi organelle is distinct from the endocytic TGN/EE in terms of its response to BFA treatment in plant cells. Thus, the Golgi and TGN are probably functionally distinct organelles in plants.