Mechanisms in COPII-Dependent Transport

COPII 依赖的运输机制

• 批准号: 9923675
• 负责人: CHARLES K BARLOWE
• 金额: $ 54.84万
• 依托单位: DARTMOUTH COLLEGE
• 依托单位国家: 美国
• 财政年份: 1995
• 资助国家: 美国
• 起止时间: 1995-05-01 至 2021-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9923675
• 关键词: Address; Amino Acids; Atherosclerosis; Back; Binding; Binding Proteins; Biochemical; Biogenesis; Biological Assay; Blood Coagulation Disorders; Blood coagulation; COPII-Coated Vesicles; Carrier Proteins; Cell physiology; Cells; Client; Coat Protein Complex I; Coatomer-Coated Vesicles; Complex; Cysteine; Cystic Fibrosis; Data; Defect; Disease; Dissociation; Disulfides; Endoplasmic Reticulum; Endoplasmic Reticulum Degradation Pathway; Ensure; Equilibrium; Futile Cycling; Goals; Golgi Apparatus; Health; Human; In Vitro; Knowledge; Measures; Membrane; Modeling; Molecular; Molecular Genetics; Monitor; Organelles; Oxidation-Reduction; Pathway interactions; Process; Protein Sortings; Proteins; Quality Control; Research; Research Proposals; Retrieval; Role; Signal Transduction; Sorting - Cell Movement; Structure; TXN gene; Testing; Translating; Vesicle; Yeast Model System; anterograde transport; base; cell growth; cellular imaging; design; disulfide bond; experimental study; human disease; improved; in vitro Assay; in vivo; misfolded protein; mutant; novel; programs; protein degradation; protein folding; protein function; protein transport; receptor; receptor binding; receptor function; reconstitution; retrograde transport; secretory protein; trafficking; vesicle transport

Project Summary Selective protein trafficking in the secretory pathway is vital for cell function and growth. Our research program is focused on coat-dependent sorting mechanisms that catalyze transport between the endoplasmic reticulum (ER) and Golgi complex. Here nascent secretory proteins are translated at the ER and then fully folded proteins are selectively packaged into COPII coated vesicles for anterograde transport to the Golgi complex. This forward pathway is balanced by retrograde transport from the Golgi, which selectively returns proteins to the ER in COPI coated vesicles. To ensure delivery of only folded secretory proteins, a process known as ER quality control retains nascent proteins in the ER until correctly folded or ultimately targets terminally misfolded proteins for degradation. Mechanisms that coordinate efficient sorting of cargo into transport vesicles with ER quality control are not well understood. We have identified a set of transmembrane cargo receptors that perform important functions in coat-dependent sorting and quality control in the early secretory pathway. This research proposal will address key questions in the field regarding how cargo binding to receptors is controlled to achieve net directional transport of proteins and how cargo receptors function in ER quality control. The specific aims of the proposal are to: (1) determine how the Erv41-Erv46 cargo receptor catalyzes retrieval of escaped ER resident proteins; (2) define molecular sorting signals in cargo that are required for Erv41-Erv46 recognition; (3) investigate how Erv41- Erv46 retrieves misfolded proteins from post-ER compartments; and (4) determine how the Erv26 and Erv29 anterograde cargo receptors function in ER quality control. We will rigorously test our hypotheses in a yeast model by exploiting molecular genetics to monitor protein function in vivo, through cell free assays with isolated ER and Golgi membranes in vitro and in reconstitution experiments with purified factors. Defining the molecular mechanisms that underlie these fundamental cellular processes should improve current approaches to treat human diseases connected to secretory pathway function.

项目摘要 分泌途径中的选择性蛋白质运输对于细胞功能和生长至关重要。我们的研究 该计划的重点是涂层依赖的分拣机制，催化运输之间的 内质网（ER）和高尔基复合体。在这里，新生分泌蛋白在ER翻译 然后完全折叠的蛋白质被选择性地包装到COPII包被的囊泡中用于顺行运输 到高尔基复合体。这一前向途径通过高尔基体的逆向转运来平衡， 选择性地将蛋白质返回到COPI包被的囊泡中的ER。为了确保仅递送折叠的分泌物， 蛋白质，一个被称为ER质量控制的过程保留了ER中的新生蛋白质，直到正确折叠或 最终靶向末端错误折叠的蛋白质进行降解。协调高效分拣的机制 货物进入运输囊泡与ER质量控制还没有得到很好的理解。我们发现了一组 跨膜货物受体，其在包衣依赖性分选和质量中发挥重要作用 控制早期分泌途径。这项研究计划将解决该领域的关键问题 关于如何控制货物与受体的结合以实现蛋白质的净定向运输， 货物受体如何在ER质量控制中发挥作用。该提案的具体目标是：（1）确定 Erv 41-Erv 46货物受体如何催化逃逸的ER驻留蛋白的回收;（2）定义 Erv 41-Erv 46识别所需的货物中的分子分选信号;（3）研究Erv 41-Erv 46如何识别Erv 41-Erv 46。 Erv 46从ER后区室中检索错误折叠的蛋白质;以及（4）确定Erv 26和Erv 46如何与ER后区室结合。 Erv 29顺行货物受体在ER质量控制中起作用。我们将严格测试我们的假设， 酵母模型，利用分子遗传学，通过无细胞测定监测体内蛋白质功能， 与分离的ER和高尔基体膜在体外和重组实验与纯化的因素。 确定这些基本细胞过程的分子机制将有助于 目前治疗与分泌途径功能相关的人类疾病的方法。