CAREER: Spatiotemporal organization of cytokinetic events

细胞通过多种过程来生长和增殖。大多数细胞过程是高度复杂的，涉及多个步骤，必须在时间和正确的区域内精确调节。不能组织这些步骤通常会导致细胞死亡。目前尚不清楚细胞如何在复杂过程中感知和发出这些不同步骤的信号以确保适当的功能。该项目将研究细胞分裂的最后一步——细胞质分裂的复杂多步骤过程。在细胞分裂过程中，一系列步骤确保母细胞分裂成两个完整的子细胞。以裂糖酵母（Schizosaccharomyces pombe）或裂变酵母（fission yeast）为模型系统，研究组织不同细胞动力学步骤的信号模式。初步数据表明，不同的信号蛋白相互作用，以适当地组织这些步骤。在这个项目中，这种串扰的分子机制以及它如何组织细胞动力学步骤将被研究。该项目将导致对原理的理解，使细胞感知和信号复杂的过程。这些原则适用于高等生物，因为大多数被研究的信号通路是高度保守的。该项目还将涉及为高中和本科生设计基于实验室的细胞生物学课程。首席研究员，一名高中科学教师和一名研究生将参与开发以实验室为基础的课程。研究生、本科生和高中生也将接受进行研究的培训。学生将在实验设计、分析和解释方面得到训练，他们的批判性思维能力将得到磨练。代表性不足的本科生和高中生将分别通过教育进步计划和向上发展计划参与该项目。所有受训者都将接受培训，以便在国家或国际会议上介绍他们的研究。细胞质分裂是分裂的最后一步，是所有真核生物普遍存在的一个过程，在这个过程中，一个细胞在核分裂后物理地分裂成两个子细胞。成功完成细胞质分裂需要多个步骤依次协调。这些步骤的正确顺序的破坏可能损害后代的遗传完整性，导致细胞分离失败，或导致细胞裂解。这个项目的目标是机械地定义不同的细胞动力学步骤是如何在时空上组织的。先前的研究表明，在分裂酵母的细胞分裂过程中，小GTPase Cdc42是启动隔膜形成所必需的。初步数据显示，Cdc42与其他RHO gtpase Rho1和Rho4串扰，组织不同的细胞动力学事件。Cdc42-Rho串扰在伤口愈合、细胞迁移和细胞极化中也有报道。然而，目前尚不清楚不同通路之间的串扰如何协调细胞过程中的多个步骤。该项目将使用细胞质分裂作为一个范例来机械地定义gtp酶之间的串扰，并解释这如何使复杂的多步骤过程协调起来。该项目将涉及跨学科方法，包括活细胞4D显微镜、分子纳米陷阱、电子显微镜和数学建模。该项目还将开发以探究为导向的细胞生物学实验室课程，以培养未来科学家探索生命规律的能力。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 employ multiple processes to grow and proliferate. Most cellular processes are highly complex, involving multiple steps that have to be precisely regulated both in time and within the correct region. Inability to organize these steps often leads to cell death. It is not clear how cells sense and signal these different steps during complex processes to ensure proper function. This project will investigate the complex multi-step process of cytokinesis, the final step in cell division. During cytokinesis, a series of steps ensures that a mother cell splits into two intact daughter cells. Using Schizosaccharomyces pombe, or fission yeast, as a model system, signaling patterns that organize different cytokinetic steps will be researched. Preliminary data show that different signaling proteins crosstalk to properly organize these steps. In this project the molecular mechanism of such a crosstalk and how it organizes cytokinetic steps will be investigated. The project will lead to an understanding of the principles that allow cells to sense and signal complex processes. These principles are applicable to higher organisms given that most of the signaling pathways investigated are highly conserved. This project will also involve the design of lab-based cell biology courses for high school and undergraduate students. The principal investigator, a high school science teacher, and a graduate student will be involved in developing the lab-based course. Graduate, undergraduate, and high school students will also be trained in conducting research. Students will be trained in experimental design, analysis and interpretation and their critical thinking capabilities will be honed. Under-represented undergraduate and high school students will participate in this project through the Educational Advancement Program and Upward Bound program respectively. All the trainees will be trained to present their research at national or international meetings.Cytokinesis, the final step in division, is a universal process in all eukaryotes in which a cell physically separates into two daughters after nuclear division. Successful completion of cytokinesis requires multiple steps that are sequentially coordinated. Disruption of the proper order of these steps can impair the genetic integrity of the progeny, lead to cell separation failure, or cause cell lysis. The goal of this project is to mechanistically define how different cytokinetic steps are spatiotemporally organized. Previous research showed the small GTPase Cdc42 to be required for initiation of septum formation during cytokinesis in fission yeast. Preliminary data show that Cdc42, crosstalk with other RHO GTPases, Rho1 and Rho4, to organize distinct cytokinetic events. Cdc42-Rho crosstalk has also been reported in wound healing, cell migration, and cell polarization. However, it is not known how crosstalk between different pathways coordinate multiple steps during cellular processes. This project will use cytokinesis as a paradigm to mechanistically define crosstalk between GTPases and explain how this enables coordination of complex multi-step processes. The project will involve interdisciplinary approaches with live cell 4D microscopy, molecular nano-traps, electron microscopy, and mathematical modeling. The project will also develop inquiry-driven cell biology lab courses to train future scientists in their quest to investigate the rules of life.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.