BRC-BIO: Investigation of the tissue-specific role of the ER membrane protein complex (EMC) in the development and maintenance of a multicellular organism

细胞需要许多蛋白质，无论是嵌入细胞膜或通过小包装移动到细胞外，用于许多过程。这些蛋白质可以提供各种基本功能，如受体，系链和其他细胞的信号。这些蛋白质通常很难折叠成正确的形状。内质网（ER）是在专门的蛋白质复合物的帮助下进行这种加工的位置。PI和本科研究人员最近发现，在神经系统的专门细胞（称为神经胶质细胞）中，ER膜蛋白复合物EMC 4的一种成分的丢失导致模型生物果蝇的寿命缩短，运动缺陷和其他有害结果。拟议的研究将调查新的问题，关于（1）在生命周期中，这种成分是生物体健康所需的，（2）神经系统中哪种类型的细胞需要这种成分正常发挥作用，以及（3）这种ER膜蛋白复合物的其他成员的作用是什么。研究这些问题将有助于深入了解ER如何处理蛋白质，以及这在生物体的专门细胞类型或生命阶段之间是否存在差异。该项目将通过指导研究经验为森林湖学院的本科生提供科学培训，改善他们进入STEM职业的机会和准备。拟议的项目还将纳入多年的基于课程的本科生研究经验（CURE），以显着增加获得宝贵的研究培训的学生人数。 最近发现的ER膜蛋白复合物（EMC）由8-10个保守亚基组成，被认为参与膜蛋白的插入、折叠和保护免于降解。然而，EMC功能的理解是有限的事实，大多数以前的工作已经在单细胞系统中进行。需要多细胞生物体来研究EMC亚基的细胞类型特异性作用或EMC功能对不同生命阶段的影响。果蝇代表了一个强大的模型系统，以回答整合EMC的分子和细胞功能及其对生物体的影响的问题。PI和本科生研究人员最近发现，EMC亚基EMC 4的果蝇同源物的胶质细胞特异性RNAi敲除（KD）严重降低了成年人的存活率。缺乏EMC 4神经胶质表达的果蝇也表现出轻度的发育延迟，但发育活力没有显著降低。EMC 4神经胶质KD果蝇还显示出严重的运动缺陷和增加的蛋白质聚集。本研究旨在研究（1）神经胶质EMC 4在不同生命阶段中的作用，特别是在发育期间与成年生物体的维持期间，（2）EMC 4在神经系统专门细胞类型中的细胞特异性功能，以及（3）任何这些表型对EMC 4与其他EMC亚基的特异性。这项研究将通过综合研究生存、行为和发育以及分子和细胞功能来促进对EMC在膜蛋白生物合成中作用的理解。该奖项反映了NSF的法定使命，并通过使用基金会的智力价值和更广泛的影响审查标准进行评估，被认为值得支持。

Cells require many proteins, either embedded in the cellular membrane or moved outside of the cell via small packages, for numerous processes. These proteins can serve a variety of essential functions, such as receptors, tethers, and signals to other cells. These proteins typically are particularly challenging to fold into the correct shape. The endoplasmic reticulum (ER) is the location where this processing occurs with the help of specialized protein complexes. The PI and undergraduate researchers recently found that loss of one component of an ER membrane protein complex, EMC4, in specialized cells of the nervous system called glia, led to a shortened lifespan, locomotor deficits, and other detrimental outcomes in the model organism, the fruit fly. The proposed research will investigate novel questions regarding (1) when during the life cycle is this component required for organismal health, (2) which types of cells in the nervous system require this component to function normally, and (3) what is the role of other members of this ER membrane protein complex. Answering these questions will provide insight into how the ER processes proteins and whether this differs between specialized cell types or life stages of an organism. This project will provide scientific training to Lake Forest College undergraduates through mentored research experiences, improving their access to and preparation for STEM careers. The proposed project will also incorporate a multi-year Course-Based Undergraduate Research Experience (CURE) to significantly increase the number of students that gain valuable research training. The recently discovered ER membrane protein complex (EMC) consists of 8-10 conserved subunits, and is thought to be involved in insertion, folding, and protection from degradation of membrane proteins. However, understanding of EMC function is limited by the fact that most prior work has been conducted in single-cell systems. A multicellular organism is required to investigate the cell type-specific roles of EMC subunits or the impact of EMC function on different life stages. Drosophila represent a powerful model system to answer questions that integrate the molecular and cellular function of EMC with its impact on the organism. The PI and undergraduate researchers recently discovered that glia-specific RNAi knockdown (KD) of the fly homolog of an EMC subunit, EMC4, severely reduces adult survival. Flies lacking glial expression of EMC4 also display a mild developmental delay, but no significant decrease in developmental viability. EMC4 glial KD flies also display severe locomotor defects and increased protein aggregation. This research proposes to investigate (1) the role that glial EMC4 plays in different life stages, specifically during development vs. during maintenance of an adult organism, (2) the cell-specific function of EMC4 in specialized cell types of the nervous system, and (3) the specificity of any of these phenotypes to EMC4 vs. other EMC subunits. This research will advance understanding of the role of EMC in membrane protein biogenesis by taking an integrative approach examining survival, behavior, and development alongside molecular and cellular function.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.