CAREER: Spatiotemporal organization of cytokinetic events

细胞通过多个过程生长和增殖。大多数细胞过程是高度复杂的，涉及多个步骤，必须在正确的时间和区域内进行精确调控。无法组织这些步骤往往会导致细胞死亡。目前尚不清楚在复杂的过程中，细胞如何感知和发送信号来确保这些不同的步骤发挥正常功能。这个项目将研究细胞质分裂的复杂的多步骤过程，这是细胞分裂的最后一步。在细胞质分裂过程中，一系列步骤确保母细胞分裂成两个完整的子细胞。以裂殖酵母为模型系统，研究组织不同细胞运动步骤的信号模式。初步数据显示，不同的信号蛋白串扰，以适当地组织这些步骤。在这个项目中，将研究这种串扰的分子机制以及它是如何组织细胞动力学步骤的。该项目将导致对允许细胞感知和发出复杂过程信号的原理的理解。这些原理适用于高等生物体，因为所研究的大多数信号通路都是高度保守的。该项目还将涉及为高中生和本科生设计以实验室为基础的细胞生物学课程。首席研究员、一名高中科学教师和一名研究生将参与开发这门以实验室为基础的课程。研究生、本科生和高中生也将接受开展研究的培训。学生将接受实验设计、分析和解释方面的培训，并磨练他们的批判性思维能力。代表不足的本科生和高中生将分别通过教育促进计划和向上跳跃计划参与这个项目。所有受训者都将接受培训，在国内或国际会议上展示他们的研究成果。细胞分裂是所有真核生物的普遍过程，细胞分裂的最后一步是细胞在核分裂后物理上分裂成两个子体。胞质分裂的成功完成需要多个顺序协调的步骤。破坏这些步骤的正确顺序可能会损害后代的遗传完整性，导致细胞分离失败，或导致细胞溶解。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，在分裂酵母的胞质分裂过程中，小的GTP酶CDC42是启动隔膜形成所必需的。初步数据显示，CDC42与其他Rho GTP酶Rho1和Rho4串扰，以组织不同的细胞动力学事件。Cdc42-Rho串扰也被报道在伤口愈合、细胞迁移和细胞极化方面。然而，不同通路之间的串扰如何协调细胞过程中的多个步骤尚不清楚。这个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能够协调。该项目将涉及活细胞4D显微镜、分子纳米陷阱、电子显微镜和数学建模等跨学科方法。该项目还将开发以探究为导向的细胞生物学实验室课程，以培训未来的科学家探索生命规则。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 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.