Bulk Flow Trafficking of Proteins within the Endoplasmic Reticulum

内质网内蛋白质的批量运输

• 批准号: 9051273
• 负责人: Laura Westrate
• 金额: $ 5.61万
• 依托单位: UNIVERSITY OF COLORADO
• 依托单位国家: 美国
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-04-01 至 2018-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9051273
• 关键词: Affect; Area; Binding; COPII-Coated Vesicles; COS-7 Cell; Calnexin; Carrier Proteins; Cell Maintenance; Cells; Cytosol; Endoplasmic Reticulum; Endosomes; Golgi Apparatus; Grant; Health; Homeostasis; Label; Lipids; Location; Mechanics; Membrane; Membrane Proteins; Methods; Microscopy; Morphology; Movement; Neurons; Nuclear Envelope; Organelles; Peripheral; Play; Process; Protein Biosynthesis; Protein Export Pathway; Proteins; RTN4 gene; Research Proposals; Role; Shapes; Signal Transduction; Site; Sorting - Cell Movement; Stretching; Surface; Techniques; Tubular formation; Work; base; calreticulin; electron tomography; insight; luminal membrane; migration; novel; overexpression; protein distribution; protein transport; public health relevance; receptor; reticulum cell; scaffold; trafficking

 DESCRIPTION (provided by applicant): The endoplasmic reticulum (ER) is a membrane bound organelle that stretches throughout the cytosol while maintaining a single lumen and is composed of multiple domains including the nuclear envelope, peripheral ER tubules and sheets. The shape of the ER plays critical roles in sustaining ER function, like protein synthesis, while also providing a cellular scaffold through which other organelles interact and are supported. Additionally, the ER is responsible for trafficking up to one third of all proteins thatit synthesizes out to various cellular locations as a critical mechanism to maintain cellular health and homeostasis. This proposal aims to determine whether the distinct structural domains of the ER also play a role in regulating the trafficking of proteins through a bulk flow mechanism. This method of protein sorting acts in a non-selective method and is instead dependent on the structural features of the organelle, specifically, the ratio of membrane area to luminal volume. Protein transport through bulk flow has previously been demonstrated in other organelles such as the endosome and golgi and it is likely that the geometric constraints of the various ER domains also function to facilitate bulk flow transport of proteins. This proposal therefore aims t understand the mechanism by which ER proteins are trafficked throughout the ER and the impact that the shape of the peripheral ER has on protein trafficking and export. By altering the shape of the ER, Aim 1 of this proposal will determine 1) how the distribution of membrane and luminal proteins are altered following changes to the geometric profile of the ER and 2) how the trafficking and movement of membrane and luminal proteins are directly affected by the morphology of the ER. Results from this aim will provide mechanistic insight in the mechanisms regulating protein distribution throughout the ER and whether protein trafficking is regulated through a bulk flow dependent manner that is dependent on the geometric profile of the peripheral ER. Aim 2 of this proposal will determine how the shape of the ER regulates protein export by 1) determining the role of ER shape on the location of COPII labeled exit sites and 2) track accumulation of secretory cargo proteins at exit sites in proximity to peripheral ER sheets and tubules. Results from this aim will provide insight into how the shape of the ER can directly regulate the targeted export of proteins from the ER. At the completion of this proposal, the mechanism by which the structural profile of the peripheral ER regulates protein trafficking and export will be established.

 描述(申请人提供)：内质网(ER)是一种膜结合的细胞器，它延伸到整个细胞质，同时保持一个管腔，由多个区域组成，包括核膜、外周ER管和片状结构。内质网的形状在维持内质网功能方面起着关键作用，比如蛋白质合成， 同时还提供细胞支架，其他细胞器通过该支架相互作用并被支撑。此外，内质网负责将其合成的高达三分之一的蛋白质运输到不同的细胞位置，这是维持细胞健康和动态平衡的关键机制。这项建议旨在确定内质网的不同结构域是否也通过大宗流动机制在调节蛋白质的运输方面发挥作用。这种蛋白质分选方法是一种非选择性的方法，取而代之的是依赖于细胞器的结构特征，特别是膜面积与腔体积的比率。先前在其他细胞器如内小体和高尔基体中已经证明了蛋白质通过散装流运输，而且很可能不同ER结构域的几何限制也促进了蛋白质的散装流运输。因此，这项提议旨在了解ER蛋白在整个内质网中被运输的机制，以及外周ER的形状对蛋白质运输和出口的影响。通过改变内质网的形状，本提案的目标1将决定1)随着内质网几何形状的变化，膜和腔蛋白的分布如何改变，以及2)膜和腔蛋白的运输和运动如何直接受到内质网形态的影响。这一目标的结果将为调控蛋白质在内质网中分布的机制以及蛋白质的运输是否通过依赖于外周内质网的几何轮廓的散装流依赖的方式进行调控提供了机械性的见解。该提案的目标2将通过以下方式确定内质网形状如何调节蛋白质输出：1)确定内质网形状对COPII标记的出口位置的作用；2)跟踪外周内质网片层和小管附近出口部位分泌货物蛋白的积累。这一目标的结果将为深入了解内质网的形状如何直接调节内质网蛋白质的靶向输出提供洞察力。在这项提议完成后，将建立外周内质网的结构特征管理蛋白质贩运和出口的机制。