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，这些蛋白质要么嵌入细胞膜，要么通过小包装转移到细胞外，以进行许多过程。这些蛋白质具有多种基本功能，如受体、系链和向其他细胞发出信号。这些蛋白质通常很难折叠成正确的形状。内质网（ER）是在特殊蛋白质复合物的帮助下进行这种加工的位置。PI和本科生研究人员最近发现，在被称为神经胶质的神经系统特化细胞中，内质网膜蛋白复合物EMC4的一种成分的缺失，会导致模式生物果蝇的寿命缩短、运动缺陷和其他有害后果。拟议的研究将探讨以下新问题：(1)在生命周期中，有机体健康何时需要这种成分；(2)神经系统中哪种类型的细胞需要这种成分才能正常工作；(3)内质网膜蛋白复合物的其他成员的作用。回答这些问题将有助于深入了解内质网是如何处理蛋白质的，以及这是否在特定细胞类型或生物体的生命阶段之间有所不同。该项目将通过指导研究经验为森林湖学院本科生提供科学培训，提高他们对STEM职业的接触和准备。拟议的项目还将包括一个多年的基于课程的本科生研究经验（CURE），以显着增加获得有价值的研究培训的学生人数。最近发现的内质网膜蛋白复合物（EMC）由8-10个保守亚基组成，被认为参与了膜蛋白的插入、折叠和防止降解。然而，由于大多数先前的工作都是在单细胞系统中进行的，因此对EMC功能的理解受到限制。需要多细胞生物来研究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来回答整合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，神经胶质特异性RNAi敲低（KD）苍蝇的一个EMC亚基，EMC4同源物，严重降低成虫的存活率。缺乏EMC4胶质表达的果蝇也表现出轻微的发育迟缓，但发育能力没有明显下降。EMC4胶质KD果蝇也表现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EMC4在不同生命阶段，特别是在成年生物体的发育和维持过程中所起的作用，(2)EMC4在神经系统特定细胞类型中的细胞特异性功能，以及(3)这些表型对EMC4与其他EMC亚基的特异性。本研究将通过对生存、行为和发育以及分子和细胞功能的综合研究，促进对EMC在膜蛋白生物发生中的作用的理解。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识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.