Plant Cell Polarization in Response to Extrinsic Cues

在真核发育过程中，细胞不对称性(极性)的获得对于细胞多样性的产生是必不可少的。内在或外在的线索引导细胞的极性，但关于细胞如何翻译极化线索来建立和维持极化状态，我们知之甚少。这个项目的总体目标是促进我们对植物细胞如何在外部提示下变得极化的理解。以前的工作发现了一种类似受体的蛋白PAN1，它与感知外部线索有关，该线索在玉米叶片气孔(表皮毛孔)的发育过程中使细胞极化。目前的项目将在这些早期发现的基础上，使用遗传学、分子和生物化学方法来促进对PAN1促进细胞极性的机制的理解，该机制以肌动蛋白细胞骨架的重组和细胞核的重新定位为标志。具体地说，该项目将阐明PAN1和已知的肌动蛋白聚合调节因子之间的联系，鉴定一种被证明以PAN1依赖的方式被磷酸化的蛋白质，以及第二个基因PAN2，这是与PAN1相同的过程所必需的，并阐明磷酸蛋白和PAN2在细胞极化中的作用。这项工作将促进对人类疾病中被错误调控的真核发育基本方面的理解，并将对科学教育产生积极影响。一名博士后、一名研究生和一名本科生将通过参与该项目接受跨学科培训。项目参与者将在圣地亚哥一所公立中学开发并领导与该项目相关的实践学习活动。因此，该项目将为美国未来的科学技术能力做出贡献。

The acquisition of cellular asymmetry (polarity) is essential for generating cell diversity during eukaryotic development. Intrinsic or extrinsic cues orient cell polarity, but relatively little is known about how cells translate polarizing cues to establish and maintain a polarized state. The overall goal of this project is to advance our understanding of how plant cells become polarized in response to extrinsic cues. Previous work discovered a receptor-like protein, PAN1, which is implicated in perception of an extrinsic cue that polarizes cells during the development of stomata (epidermal pores) in maize leaves. Current project will build on these earlier findings using genetic, molecular and biochemical approaches to advance the understanding of mechanisms by which PAN1 promotes cell polarity marked by reorganization of the actin cytoskeleton and re-positioning of the nucleus. Specifically, the project will elucidate the connections between PAN1 and known regulators of actin polymerization, to identify a protein shown to be phosphorylated in a PAN1-dependent manner as well as a second gene, PAN2, which is required for the same processes as PAN1, and to elucidate the roles of the phosphoprotein and PAN2 in cell polarization. This work will advance the understanding of fundamental aspects of eukaryotic development that are misregulated in human diseases, and will also have a positive impact on science education. A postdoc, a graduate student, and an undergraduate will receive interdisplinary training through participation in this project. Project participants will develop and lead hands-on learning activities related to this project in a public San Diego Middle School. Thus, this project will contribute to future science and technology capabilities in the United States.