Signaling to Cellular Intercalation in Arabidopsis

拟南芥中细胞嵌入的信号转导

• 批准号: 8333384
• 负责人: Zhenbiao Yang
• 金额: $ 29.27万
• 依托单位: UNIVERSITY OF CALIFORNIA RIVERSIDE
• 依托单位国家: 美国
• 财政年份: 2007
• 资助国家: 美国
• 起止时间: 2007-09-01 至 2015-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8333384
• 关键词: Actins; Active Sites; Animals; Appearance; Arabidopsis; Auxins; Award; Biological Assay; Biological Models; Cell Polarity; Cell Wall; Cell surface; Cells; Clathrin; Cytokinins; Cytoskeleton; Development; Embryonic Development; Endocytosis; Epidermis; Event; Exhibits; Failure; Feedback; Gene Targeting; Generations; Genes; Genetic Transcription; Goals; Growth; Guanosine Triphosphate Phosphohydrolases; Health; Hereditary Disease; Hormones; Human; Image; In Vitro; Intercalated Cell; Investigation; Knowledge; Link; Lobe; Mediating; Microtubules; Modeling; Morphogenesis; Neural Tube Defects; Nuclear; Organ; Organism; Pathway interactions; Pattern; Pattern Formation; Phosphotransferases; Plant Leaves; Plant Model; Plants; Pregnancy; Process; Protein Kinase; Recycling; Reporter; Research; Role; Side; Signal Pathway; Signal Transduction; Site; Surface; System; Testing; WNT Signaling Pathway; Work; auxin-binding protein 1; base; cell growth; design; developmental disease; in vivo; insight; intercalation; interest; mathematical model; mutant; novel; receptor; response; rho; rho GTP-Binding Proteins; sensor; small molecule; time use; trafficking

DESCRIPTION (provided by applicant): The long-term goal of this project is to elucidate how cell polarity and morphogenesis is coordinated locally (between adjacent cells) and globally (in a field of cells) along the organ surface, because this knowledge is sorely needed to understand mechanisms of development and pattern formation. This project focuses the mechanisms underlying cellular intercalation, a fundamental process critical for human and animal embryogenesis and plant morphogenesis. Mechanisms for the local and global coordination of cellular intercalation are poorly characterized, although some underlying signaling events (e.g., Rho GTPases and the cytoskeleton) are conserved across animal and plant kingdoms. In the model plant Arabidopsis, cell intercalation is important for the development of the leaf epidermis, in which pavement cells (PC) develop interdigitated lobes and indentations to form the puzzle-piece appearance. The PI's group has established PC as a model system for cell intercalation and has discovered an elaborate Rho GTPase signaling network underpinning the PC intercalation, which involves two interplaying but mutually exclusive Rho signaling pathways: The ROP2-RIC4-actin pathway activating lobe formation and the ROP6-RIC1-microtubule pathway promoting indentation. The two pathways are complementarily localized at the opposing sides of the cell wall, but are both activated by a small molecule hormone known as auxin via the cell-surface ABP1 receptor; and the ROP2 pathway forms a positive feedback loop by activating the polarization of PIN1, which exports auxin to the cell wall. This auxin-modulated network is proposed to locally coordinate PC intercalation and to be linked to the global coordination mediated by leaf tip- and margin-high auxin gradients, which are apparently generated by a different transcription-based auxin-signaling pathway dependent on the nuclear TIR1/AFB auxin receptor. The objective of this proposal is to test the hypothesis that PC intercalation is coordinated by hierarchical auxin signaling, which may be mirrored by WNT signaling that modulates developmental patterns in animals. Aim 1 focuses detailed mechanisms by which auxin locally coordinates PC intercalation, including putative ABP1 co-receptors that are transmembrane receptor-like kinases, their differential activation of the two Rho pathways, PIN1-mediated local extracellular auxin, and its coordination of these pathways. Aim 2 will elucidate the mechanisms by which ROP2 activates PIN1 polarization via endosomal PIN1 trafficking. Aim 3 will determine roles of the TIR1/AFB pathway and its target genes in the global coordination. The work will provide a comprehensive view of the mechanisms coordinating cellular intercalation at multiple levels. Given the conserved Rho signaling underlying cell intercalation and planar cell polarity (PCP) across plants and humans, the proposed work may provide new insights into convergent extension (CE) and other PCP- mediated processes. Because failure in CE causes neural tube defects, a common developmental disorder (1 out of 1000 pregnancies), this research might ultimately be relevant to human health improvements.

描述（由申请人提供）：该项目的长期目标是阐明细胞极性和形态发生如何在本地（相邻细胞之间）和沿着器官表面的全球（在一个细胞领域）进行协调，因为这种知识非常需要了解发展和模式形成的机制。该项目集中了细胞插入的基础机制，这是对人类和动物胚胎发生和植物形态发生至关重要的基本过程。局部和全球细胞插入的机制的特征很差，尽管在动物和植物王国中保守了一些潜在的信号事件（例如Rho GTPases和细胞骨架）。在模型植物拟南芥中，细胞插入对于叶片表皮的发展很重要，其中人行道细胞（PC）会形成相互插的叶和压痕以形成拼图件外观。 The PI's group has established PC as a model system for cell intercalation and has discovered an elaborate Rho GTPase signaling network underpinning the PC intercalation, which involves two interplaying but mutually exclusive Rho signaling pathways: The ROP2-RIC4-actin pathway activating lobe formation and the ROP6-RIC1-microtubule pathway promoting indentation.这两种途径在细胞壁的相对侧互补，但都被细胞表面ABP1受体称为生长素的小分子激素激活。 ROP2途径通过激活PIN1的极化形成正反馈回路，PIN1的极化将生长素导出到细胞壁。提出了该生长素调节的网络来局部协调PC的插入，并与叶尖端和边缘高的生长素梯度介导的全局配位相关联，显然是由不同的基于基于转录的生长素的辅助途径依赖于核TIR1/AFB AFB AFB AFB辅助素受体而产生的。该提案的目的是检验以下假设：PC插入是通过层次生长素信号协调的，这可以通过Wnt信号来反映，该信号调节动物的发育模式。 AIM 1聚焦的详细机制，通过该机制，生长素局部协调PC的插入，包括推定的ABP1共受体，它们是跨膜受体样激酶，它们对两种RHO途径的差异激活，PIN1介导的局部局部外的细胞外生长素及其这些途径的配位。 AIM 2将阐明ROP2通过内体PIN1运输激活PIN1极化的机制。 AIM 3将确定TIR1/AFB途径及其目标基因在全球协调中的作用。这项工作将提供有关在多个级别协调细胞插入的机制的全面视图。考虑到跨植物和人类的固定RHO信号传导基础细胞插入和平面细胞极性（PCP），拟议的工作可能会为收敛扩展（CE）和其他PCP介导的过程提供新的见解。由于CE失败会导致神经管缺陷，因此是一种常见的发育障碍（1000例怀孕中的1个），这项研究最终可能与人类健康的改善有关。