The structure and dynamics of the plant endoplasmic reticulum - WCUB, ENWW

内质网（ER）作为连接膜室的亚细胞“高速公路”。内质网在稳定的内质膜接触位点（epcs）[2][3]连接到质膜（PM），这些位点与脂质转运、感染反应有关，并可能作为细胞骨架的“组织枢纽”（见[4]）。植物epcs的两种成分已被确定：NET3C，一种连接epcs与肌动蛋白细胞骨架的肌动蛋白结合蛋白；VAP27，一种囊泡相关膜蛋白（VAMP）相关蛋白（VAP）家族成员[5]。这些EPCS成分在控制内质网结构中的作用将通过显性阴性突变体和过表达突变体进行评估，并使用新型内质网网络分析软件分析对内质网动力学的影响。使用一种新的分子工具箱，现在可以瞬时修改内质网结构。内质网由两个形态不同的结构域（片和小管）组成，它们以三向连接连接在一起（见[6]）。这些结构在不同的细胞类型中以不同的相对比例存在，这取决于细胞的分泌需求。拟南芥reticulon蛋白的瞬时过表达可诱导内质网内的管状结构[8,9]，而拟南芥Lunapark蛋白的瞬时过表达可诱导内质网内的片状结构。这些蛋白质过度表达引起的内质网动力学变化将使用上述软件和单粒子跟踪技术进行分析。内质网的运动是由底层的肌动蛋白细胞骨架[10]控制的。因此，与野生型相比，在改良的ER和EPCS背景下，将分析肌动蛋白细胞骨架的动力学和结构。

The endoplasmic reticulum (ER) acts as a subcellular \superhighway" that connects membrane compartments [1]. The ER connects to the plasma membrane (PM) at stable ER-PM contact sites (EPCSs) [2] [3] which have been implicated in lipid transport, infection response and may act as \organizational hubs" for the cytoskeleton (reviewed in [4]). Two components of the plant EPCSs have been identified: NET3C, an actin binding protein which connects EPCSs to the actin cytoskeleton, and VAP27 a member of the vesicle-associated membrane protein (VAMP)-associated protein (VAP) family [5]. The role of these EPCS components in controlling ER structure will be assessed using dominant-negative mutants and over-expression mutants, and the effect on ER dynamics analysed using novel ER network analysis software. Using a novel molecular toolbox it is now possible to transiently modify ER structure. The ER is composed of two morphologically distinct domains { sheets and tubules, that are joined at three-way junctions (reviewed in [6]). These structures are present in different relative proportions in different cell types depending on the cells secretory requirements [7]. Transient over-expression of Arabidopsis thaliana reticulon proteins has been shown to induce tubular structures within the ER [8, 9], whilst transient over-expression of the A. thaliana Lunapark proteins induces sheet-like structures. Changes to ER dynamics caused by over-expression of these proteins will be analysed using the aforementioned software and with single-particle tracking technology. The movement of the ER is controlled by the underlying actin cytoskeleton [10]. As such the dynamics and structure of the actin cytoskeleton will be analysed in modified ER and EPCS backgrounds compared to wild-types.