CAREER: Organelle Networks Orient Cilia and First-Generation College Students for Success

该奖项全部或部分由《2021年美国救援计划法案》（公法117-2）资助。这个项目的目标是研究纤毛在细胞表面的定位机制。纤毛是进化上古老的毛发状附属物，对细胞运动和感觉至关重要。了解纤毛的位置是很重要的，因为纤毛的位置影响着陆生和水生生物获取营养、感知环境和繁殖的方式。这项研究是基于这样的假设，即相互连接的细胞器网络决定了纤毛在哪里形成，纤毛如何感知分子，以及纤毛如何移动液体。这项研究将由一个主要由本科生科学家组成的团队进行，他们将获得尖端荧光显微镜、图像分析和进化分化细胞的遗传操作方面的经验。通过提案产生的科学数据将用于创建跨学科的数学建模课程，以教授纤毛内的扩散。在教学和科研之外，这个项目的一个主要目标是为有抱负的第一代大学生形成一个纵向的指导计划。在项目的第一年，将从当地一所有资格获得联邦大学准备援助（GEAR UP）的低收入高中召集一批九年级学生。在他们的高中生涯中，这个队列将从事细胞生物学研究，以了解当地河流中的水污染如何影响纤毛运动。学生的科学训练将与家庭参与、丰富活动和大学申请协助相辅相成，以增加这些学生在项目完成后参加STEM本科课程的可能性。美国救援计划对该项目的资助支持了这位研究人员在其职业生涯的关键阶段。纤毛是一种基于微管的结构，从单细胞生物（如四膜虫）到多细胞生物（如人类）的细胞表面突出。纤毛的分子结构是高度保守的；在大多数被检查的生物体中，纤毛由9个径向对称的双重微管组成，称为轴突，组装在9个径向对称的三重微管之上，称为基体。尽管纤毛分子结构具有很强的保守性，但纤毛相对于细胞几何形状的物理位置并不保守。本项目利用进化上的分化细胞来验证基底体附近的膜结合细胞器如何参与纤毛的定位、信号传导和弯曲特性的假设。该研究将调查单细胞原生生物四膜虫和来源于小鼠和人类的细胞培养物中膜结合细胞器和基底体之间的相互作用。这种比较方法旨在通过动态活细胞荧光显微镜、Förster共振能量转移（FRET）、荧光寿命成像显微镜（FLIM）、比例钙显微镜、药理学和遗传摄动来确定纤毛定位的保守机制。总的来说，这个项目的结果将揭示影响细胞如何定位纤毛相对于细胞几何的基本机制。这些结果对纤毛如何组织以最大限度地提高水生环境中的细胞运动和细胞外空间信号的转导具有启示意义。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。

This award is funded in whole or in part under the American Rescue Plan Act of 2021 (Public Law 117-2).The goal of this project is to investigate the mechanisms that position cilia across the surface of cells. Cilia are evolutionarily ancient hair-like appendages that are critical for cell movement and sensation. Understanding how cilia are positioned is important because the position of cilia affects how both terrestrial and aquatic organisms acquire nutrients, sense their environment, and reproduce. This research is based on the hypothesis that networks of interconnected organelles determine where cilia form, how cilia sense molecules, and how cilia move fluid. This research will be conducted by a team of primarily undergraduate student scientists, who will gain experience in cutting-edge fluorescence microscopy, image analysis, and genetic manipulation of evolutionarily divergent cells. The scientific data generated through the proposal will be used to create an interdisciplinary mathematical modeling curriculum for teaching diffusion within cilia. Beyond teaching and scientific research, a major goal of this project is to form a longitudinal mentoring program for aspiring first-generation college students. During year 1 of the project, a cohort of 9th grade students will be assembled from a local low-income high school that qualifies for federal college preparation assistance (GEAR UP). Throughout their high school career, this cohort will engage in cell biology research to understand how water pollution in a local river impacts cilia movement. Student scientific training will be complemented with family engagement, enrichment activities and college application assistance to increase the likelihood that these students enroll in STEM undergraduate programs at the completion of the project. American Rescue Plan funding of this project supports this researcher at a critical stage in his career. Cilia are microtubule-based structures that project from the surface of cells that span unicellular organisms, such as Tetrahymena, through multi-cellular organisms, such as humans. The molecular architecture of cilia is deeply conserved; in most organisms examined, cilia are composed of 9 radially symmetric doublet microtubules, called an axoneme, assembled on top of 9 radially symmetric triplet microtubules, called a basal body. Despite the strong conservation of cilia molecular architecture, the physical location of cilia relative to the geometry of the cell is not conserved. This project utilizes evolutionarily divergent cells to test hypotheses for how membrane-bound organelles adjacent to basal bodies participate in the positioning, signaling, and bending properties of cilia. The research will investigate interactions between membrane-bound organelles and basal bodies in both the unicellular protist Tetrahymena and cell cultures derived from mice and humans. This comparative approach aims to identify conserved mechanisms of cilia positioning using dynamic live-cell fluorescence microscopy, Förster Resonance Energy Transfer (FRET) quantified with Fluorescence Lifetime Imaging Microscopy (FLIM), ratiometric calcium microscopy, pharmacology, and genetic perturbations. Overall, the results from this project will reveal fundamental mechanisms that impact how cells position cilia relative to cellular geometry. These results have implications for how cilia are organized to maximize cellular motility in aquatic environments and the transduction of signals from the extracellular space.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.