Elucidating the role of a GTPase-regulating protein family during tip growth initiation and regulation in roots

阐明 GTP 酶调节蛋白家族在根尖生长起始和调节过程中的作用

• 批准号: 440951825
• 负责人: Professor Dr. Guido Grossmann
• 金额: --
• 依托单位: Institut für Zell- und Interaktionsbiologie
• 依托单位国家: 德国
• 项目类别: Research Grants
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/440951825?language=en
• 关键词: Elucidating; role; GTPase; regulating; protein

The diversity of cellular shapes among eukaryotes depends on the ability of cells to define polar growth axes and regulate the rate of cell expansion. The interdependence of form and function is particularly evident in cells that use directed growth to explore and invade their environment and to penetrate dense substrates. To initiate a new growing tip, cells concentrate their resources and maximize mechanical forces at a confined spot at the plasma membrane. Such polarized growth is a common feature among eukaryotes and can be observed, for instance, in fungal hyphae, neuronal axons, and plant pollen tubes and root hairs. While numerous components and regulators of polarized growth in various cell types and organisms have been identified, fundamental questions remain to be answered, such as how the position of a polar domain is defined, how the growth machinery is assembled, or how tip growth is initiated, regulated and ultimately completed.In order to elucidate the mechanisms of cell morphogenesis in plants, we investigate the formation of root hairs, tip-growing structures of trichoblast cells, a cell type of the root epidermis. Root hairs help plants to extract water and mineral nutrients from soil, to anchor the root and to interact with microbes in the rhizosphere.In this project, we are focussing on the protein family of growth-regulating RopGEFs and their functions during cell polarization and tip growth regulation. RopGEFs are responsible to activate molecular switches, so-called ROP-GTPases, that integrate intra- and extracellular signals to modulate the growth machinery. We recently found that the polar association of RopGEFs with the plasma membrane is specifically timed accross different stages of root hair development: some members are involved in marking the site of outgrowth, while others have a regulatory function after growth has begun. Here we aim to elucidate the mechanisms that underlie this timed polar association and activity, as well as the different functions that are exerted by different RopGEFs. The findings of this study are expected to lead us to a better understanding of cell morphogenesis and the the emergence of tip-growing structures in plant cells.

真核生物中细胞形状的多样性取决于细胞确定极性生长轴和调节细胞扩增速率的能力。形式和功能的相互依赖性在使用定向生长来探索和侵入其环境并穿透致密基质的细胞中特别明显。为了启动一个新的生长尖端，细胞将它们的资源集中在质膜上的一个有限的点上，并使机械力最大化。这种极化生长是真核生物中的共同特征，并且可以在例如真菌菌丝、神经元轴突和植物花粉管和根毛中观察到。虽然在各种细胞类型和生物体中极化生长的许多组分和调节剂已经被确定，但基本问题仍然有待回答，例如极性域的位置如何定义，生长机制如何组装，或尖端生长如何启动，调节和最终完成。毛细胞的顶端生长结构，毛细胞是根表皮的一种细胞类型。根毛是植物从土壤中吸收水分和矿物质的重要器官，具有锚根系的作用，并与根际微生物相互作用。本项目主要研究生长调节蛋白RopGEFs家族及其在细胞极化和根尖生长调节中的作用。RopGEF负责激活分子开关，即所谓的ROP-GTP酶，其整合细胞内和细胞外信号以调节生长机制。我们最近发现RopGEFs与质膜的极性结合在根毛发育的不同阶段有特定的时间：一些成员参与标记生长部位，而另一些成员在生长开始后具有调节功能。在这里，我们的目标是阐明这种定时极性关联和活动的机制，以及不同的RopGEFs所发挥的不同功能。本研究的结果有望使我们更好地了解细胞形态建成和尖端生长结构在植物细胞中的出现。