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，进行许多过程。这些蛋白质可以提供各种基本功能，如受体、连接和向其他细胞发送信号。这些蛋白质通常特别难折叠成正确的形状。内质网(ER)是在特殊蛋白质复合体的帮助下进行这种加工的地方。PI和本科生的研究人员最近发现，神经系统胶质细胞中ER膜蛋白复合体的一种成分EMC4的缺失，会导致模式生物--果蝇的寿命缩短、运动障碍和其他有害后果。这项拟议的研究将调查以下新问题：(1)在生命周期中，这种成分对生物体健康是必需的；(2)神经系统中哪些类型的细胞需要这种成分才能正常发挥作用；以及(3)这种内质网膜蛋白复合体的其他成员起什么作用。回答这些问题将使我们深入了解内质网如何处理蛋白质，以及这是否在特定细胞类型或有机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莱克森林学院的本科生提供科学培训，改善他们进入STEM职业生涯的机会和准备。拟议的项目还将纳入以多年课程为基础的本科生研究体验(CURE)，以显著增加获得有价值的研究培训的学生数量。最近发现的内质网膜蛋白复合体(EMC)由8-10个保守亚基组成，被认为参与了膜蛋白的插入、折叠和保护作用。然而，大多数先前的工作都是在单电池系统中进行的，这限制了人们对EMC功能的理解。多细胞生物体需要研究EMC亚基在细胞类型中的特定作用或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，可以回答将EMC的分子和细胞功能与其对有机体的影响相结合的问题。PI和本科生的研究人员最近发现，EMC亚单位EMC4的苍蝇同系物的胶质细胞特异性RNAi敲除(KD)严重降低了成虫的存活率。缺乏EMC4神经胶质表达的果蝇也表现出轻微的发育延迟，但发育活力没有显著下降。EMC4胶质细胞KD果蝇也表现出严重的运动缺陷和蛋白质聚集增加。这项研究建议研究(1)胶质细胞EMC4在不同的生命阶段，特别是在成年生物体的发育和维持期间所扮演的角色，(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)这些表型中的任何一种对EMC4相对于其他EMC亚单位的特异性。这项研究将通过采用一种综合的方法来研究生存、行为和发育以及分子和细胞功能，从而促进对EMC在膜蛋白生物发生中的作用的理解。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势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.