RUI: Exploring the Function of FtsZs and the Cytoskeleton to Determine the Molecular Mechanism of Mitochondrial Dynamics in Dictyostelium discoideum

细胞线粒体调节许多过程，如钙水平和程序性细胞死亡。然而，它们最为人所知的是能量转导，通常被称为细胞的动力源。这个项目的重点是线粒体结构，因为没有合适的结构，线粒体就会功能失调。虽然线粒体是从祖先的细菌细胞发展而来，但不同的生物（如人类、变形虫、藻类、酵母等）以不同的方式维持线粒体结构。如果我们能理解维持这些生物体结构的机制，我们就能了解为什么这些机制是不同的，同时也能深入了解线粒体功能障碍的原因。这个项目更广泛的影响包括这项工作的内在价值，因为绝大多数真核细胞都含有这些细胞器。其他活动将涉及K-16学生。阿肯色州中部一所本科大学的学生将完成这个项目。接触高质量、资金充足的研究，使学生有能力探索研究是否适合他们的职业选择。它为攻读博士课程的学生做准备，并指导学生进行研究，这对于保留那些传统上在STEM领域代表性不足的群体至关重要。除了培训本科生外，这个项目还涉及到K-6学生。该计划将与当地小学建立正式的关系，特别是那些ACT Aspire分数显示科学能力不足的小学。通过动手活动与K-6学生互动，旨在激励学生，向他们展示科学的乐趣，并继续发展他们的科学探究技能。线粒体的基本功能依赖于它们的结构，而结构又依赖于线粒体动力学、裂变、融合和运动。在许多细胞类型中，如哺乳动物细胞和酵母细胞，一种被称为动力蛋白相关蛋白（DRPs）的蛋白质家族维持着线粒体的高度互联网络。重要的是，我们的模式生物盘状盘齿龙不使用DRPs来调节线粒体动力学。相反，盘状棘球蚴的基因组编码两种蛋白，FszA和FszB，它们来源于细菌的细胞分裂蛋白FtsZ。目前尚不清楚为什么有些生物体使用DRPs，而有些生物体使用似乎衍生的FtsZ蛋白。本研究的长期目标是了解盘状棘球蚴线粒体动力学的分子机制，以确定一些生物体在进化过程中何时以及为何用DRPs取代ftsz。第一个项目目标是确定现存的FtsZs在线粒体动力学中的作用，将涉及改变蛋白质水平，识别相互作用的蛋白质，并分析FtsZs的结构复合物。最近的研究表明，细胞骨架是线粒体动力学调节的主要参与者，该项目的第二个目标是通过识别分裂/融合事件，以及细胞骨架被破坏时的传输速度，研究细胞骨架与线粒体动力学的关系。该项目的完成将有助于确定FtsZs是否像DRPs一样起作用，以及盘状龙骨细胞骨架如何调节线粒体动力学。最终，这项工作将有助于理解线粒体的进化和线粒体动力学，特别是为什么一些生物体使用DRPs而一些生物体使用ftsz。该项目由分子和细胞生物科学部和刺激竞争性研究的既定计划（EPSCoR）共同资助。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。

Cellular mitochondria regulate many processes, such as calcium levels and programmed cell death. However, they are best known for energy transduction and are often referred to as the powerhouse of the cell. This project focuses on mitochondrial structure because without appropriate structure, mitochondria become dysfunctional. Although mitochondria developed from an ancestral bacterial cell, different organisms (e.g., humans, amoeba, algae, yeast, etc.) maintain mitochondrial structure in different ways. If we can understand the mechanisms that maintain structure across these organisms, we can learn why the mechanisms are different while also gaining insight into the causes of mitochondrial dysfunction. The broader impacts of this project include the intrinsic merit of the work as the vast majority of eukaryotic cells contain these organelles. Other activities will involve K-16 students. Students at a primarily undergraduate university in central Arkansas will carry out this project. Exposure to quality, well-funded research provides students the ability to explore whether research is an appropriate career choice for them. It prepares students for doctoral programs, and mentoring students in research is critical for retention of those from groups traditionally underrepresented in STEM. In addition to training undergraduates, this project involves outreach to K-6 students. The plan is to formalize relationships with local elementary schools, specifically ones whose ACT Aspire scores indicate a deficit in science. Interactions with K-6 students via hands-on-activities are designed to inspire students, show them that science is fun, and continue to develop their scientific inquiry skills. The essential functions of the mitochondria are dependent upon their structure, which, in turn, is dependent upon mitochondrial dynamics, fission, fusion, and motility. In many cell types such as mammalian and yeast cells, a protein family known as dynamin-related proteins (DRPs) maintains the highly interconnected network of mitochondria. Importantly, our model organism, Dictyostelium discoideum does not use DRPs to regulate mitochondrial dynamics. Rather, the D. discoideum genome encodes two proteins, FszA and FszB, which are derived from the bacterial cell division protein, FtsZ. It is not understood why some organisms use DRPs and some use what appears to be derived FtsZ proteins. A long-term goal of this research is to understand the molecular mechanism of mitochondrial dynamics in D. discoideum in order to identify when and why some organisms replaced FtsZs with DRPs as they evolved. The first project goal is to identify the role of extant FtsZs in mitochondrial dynamics and will involve altering protein levels, identifying interacting proteins, and analyzing FtsZs structural complexes. Recent work has shown that the cytoskeleton is a major player in the regulation of mitochondrial dynamics, and the second goal of this project is to study the relationship of the cytoskeleton with mitochondrial dynamics by identifying fission/fusion events, along with transport velocities when the cytoskeleton is disrupted. Completion of this project will help determine if FtsZs function like DRPs, and how the D. discoideum cytoskeleton regulates mitochondrial dynamics. Ultimately, this work will contribute to understanding the evolution of mitochondria and mitochondrial dynamics and specifically why some organisms use DRPs and some use FtsZs.This project is jointly funded by the Division of Molecular and Cellular Biosciences and the Established Program to Stimulate Competititive Research (EPSCoR).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.