ER-TO-GOLGI TRANSPORT IN HIGHER PLANT CELLS: NEW STRUCT & A NEW MECHANISM

高等植物细胞中的内质网到高尔基体的运输：新结构

• 批准号: 7355007
• 负责人: ANDREW L. STAEHELIN
• 金额: $ 0.47万
• 依托单位: UNIVERSITY OF COLORADO
• 依托单位国家: 美国
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-09-26 至 2007-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7355007
• 关键词: plants; ribosomes; root

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Plant Golgi stacks travel along actin filament bundles in a "Stop and Go" pattern of movement. This Stop and Go pattern is characterized by alternations between rapid straight displacements (go phase), and random wiggling at set locations (stop phase). Wiggling Golgi stacks are associated transiently with ER export sites (tER) marked by the Sec13 protein, a component of the COPII vesicular transport machinery. This suggests that the ER-to-Golgi transport in plant cells takes place during transient interactions between these two compartments. We have investigated Golgi stacks and the ER in Arabidopsis thaliana and in alfalfa root meristem and columella cells, using electron tomography and immunoelectron microscopy. tER sites were identified by the presence of budding COPII vesicles labeled by antisera against AtSar1p. A fraction of the Golgi stacks were located close to ER export sites, and these Golgi appeared to be connected to the tER sites through a ribosome-excluding matrix. ER export sites tend to be organized around the cis-side of close Golgi stacks. All of the COPII vesicles were surrounded by a ribosome-excluding matrix, both while budding and during their transfer to the Golgi. COPII vesicles were seen within the Golgi matrix of docked Golgi stacks and these always displayed a small, irregularly shaped cis-most cisterna. Golgi stacks not connected to ER export sites contained few COPII vesicles in their matrices and lacked characteristic cis-cisternal assembly intermediates. In root columella cells, the ER is confined to cortical region of the cytoplasm. Golgi stacks in the cell cortex were also coupled to ER export sites via a matrix and displayed assembling cis-cisternae; those near the cell's center lacked these structures. Together, these findings demonstrate that COPII vesicle-mediated transport occurs during the "stop" phase of Golgi movement, and that the process of stopping involves the formation of transient links between the ribosome-excluding matrix of forming COPII vesicles and the cis-side of the Golgi matrix.

该子项目是利用 NIH/NCRR 资助的中心拨款提供的资源的众多研究子项目之一。子项目和研究者 (PI) 可能已从另一个 NIH 来源获得主要资金，因此可以在其他 CRISP 条目中得到体现。列出的机构是中心的机构，不一定是研究者的机构。植物高尔基体堆栈沿着肌动蛋白丝束以“走走停停”的运动模式移动。这种停止和前进模式的特点是快速直线位移（前进阶段）和在设定位置随机摆动（停止阶段）之间的交替。摆动的高尔基体堆栈与由 Sec13 蛋白标记的 ER 输出位点 (tER) 短暂相关，Sec13 蛋白是 COPII 囊泡运输机制的一个组成部分。这表明植物细胞中内质网到高尔基体的转运发生在这两个区室之间的短暂相互作用期间。我们使用电子断层扫描和免疫电子显微镜研究了拟南芥和苜蓿根分生组织和小柱细胞中的高尔基体堆栈和内质网。 tER 位点通过 AtSar1p 抗血清标记的出芽 COPII 囊泡的存在来识别。一小部分高尔基体堆栈位于 ER 输出位点附近，这些高尔基体似乎通过核糖体排除矩阵与 tER 位点相连。 ER 输出位点往往围绕紧密的高尔基体堆栈的顺侧组织。所有 COPII 囊泡在出芽时和转移到高尔基体期间都被排除核糖体的基质包围。在对接的高尔基体堆叠的高尔基体基质内可以看到 COPII 囊泡，这些囊泡总是显示出一个小的、不规则形状的顺式池。未与 ER 输出位点连接的高尔基体堆栈在其基质中含有很少的 COPII 囊泡，并且缺乏特征性的顺式脑池组装中间体。在根小柱细胞中，内质网仅限于细胞质的皮质区域。细胞皮层中的高尔基体堆栈也通过矩阵与内质网输出位点偶联，并显示出组装顺式池；靠近细胞中心的细胞缺乏这些结构。总之，这些发现表明 COPII 囊泡介导的运输发生在高尔基体运动的“停止”阶段，并且停止过程涉及形成 COPII 囊泡的核糖体排除基质与高尔基体基质的顺侧之间的瞬时连接的形成。