The role of ELMOD family proteins and their genetic network in the development of specialized membrane domains on the Arabidopsis pollen surface

为了使细胞正确地生长、分裂和移动，形成适当的形状，向邻近细胞发送信号，运输营养物质，并保护自己，它们通常必须将某些分子引导到表面的特定区域。由此产生的区域已知在化学上与细胞表面的其他部分不同，但是细胞如何决定在哪里形成这些区域以及它们应该采用什么形状还不是很清楚。为了研究这些问题，本项目将对花粉粒进行研究。花粉表面有一些特殊的区域，称为花粉孔，它与花粉表面的其他部分不同，在显微镜下很容易识别。在同一种植物中，所有的光圈都趋向于在相同的位置发育并获得相同的形状，而在不同的植物物种中，光圈模式往往差异很大。在玉米和水稻等重要作物中，如果缺少孔洞，花粉就会不育。因此，了解这些区域是如何形成的对于控制植物繁殖是很重要的。该项目将重点研究哪些蛋白质参与了孔的形成，以及这些蛋白质在这个过程中发挥了什么作用。该项目的广泛影响将包括：a)研究本身的内在价值，因为孔对植物繁殖很重要；B)对从博士后到本科生的几名年轻科学家进行了经典和分子遗传学、植物生物学、显微镜学和生物化学方法的培训；c)通过一系列活动教育公众花粉在植物生命周期中的重要性。为了正确地发挥其功能，细胞通常在质膜上形成不同的区域，将特定的蛋白质、脂质和其他分子招募到这些区域。然而，产生这些结构域的分子机制还没有被很好地理解，特别是对于植物细胞。花粉表面没有花粉壁外壁的特定区域，称为花粉孔，是由花粉前体细胞质膜上形成的不同的孔域产生的。花粉孔易于识别和量化，为研究植物细胞如何形成质膜结构域以及它们如何选择和指定这些结构域发育的位点提供了一个强大的模型。最近发现，吞噬和运动结构域（吞噬和运动结构域）蛋白家族的几个成员在拟南芥花粉的孔径结构域规范过程中起着重要作用，控制着孔径结构域的数量和形状。然而，ELMOD蛋白如何促进孔结构域的形成以及这些蛋白在植物细胞中起什么分子作用是完全未知的。通过各种遗传、生化和成像方法，该项目将确定植物ELMOD蛋白的作用，并确定在孔径结构域规范中与ELMOD蛋白一起起作用的遗传网络成员。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。

In order for cells to correctly grow, divide and move, develop proper shapes, send signals to their neighbors, transport nutrients, and protect themselves, they often must direct certain molecules to specific regions on their surface. The resulting regions are known to be chemically distinct from the rest of the cellular surface, but how cells determine where to form these regions and what shape they should adopt is not well understood. To investigate these questions, this project will study pollen grains. Pollen has characteristic regions on its surface, called pollen apertures, which differ from the rest of the pollen surface and can be easily recognized under a microscope. Within a plant species, all apertures tend to develop at the same positions and acquire the same shape, whereas across plant species, aperture patterns often vary widely. In important crops such as corn and rice, pollen becomes sterile if apertures are missing. Thus, understanding how these regions form is important for control of plant reproduction. This project will focus on investigating what proteins are involved in aperture formation and what roles these proteins play in this process. The Broader Impacts of this project will include: a) the intrinsic merit of the research itself as apertures are important for plant reproduction; b) the training of several young scientists, from postdocs to undergraduate students, in methods of classical and molecular genetics, plant biology, microscopy, and biochemistry; and c) educating the general public about the importance of pollen in plant life cycle through a range of activities. To properly perform their functions, cells often form distinct domains in their plasma membranes, recruiting to these domains specific proteins, lipids, and other molecules. Yet the molecular mechanisms creating such domains are not well understood, particularly for plant cells. Specific regions on pollen surface devoid of the pollen wall exine, known as pollen apertures, are produced from the distinct aperture domains that form in the plasma membrane of the pollen precursor cells. Easily recognizable and quantifiable, pollen apertures present a powerful model for studying how plant cells form plasma membrane domains and how they select and specify sites where these domains would develop. Several members of the ENGULFMENT AND MOTILITY DOMAIN (ELMOD) protein family were recently found to be essential players in the process of aperture domain specification in Arabidopsis pollen, controlling the number and shape of aperture domains. Yet how ELMOD proteins promote formation of aperture domains and what molecular roles these proteins play in plant cells is completely unknown. Through a variety of genetic, biochemical, and imaging approaches, this project will define the roles of plant ELMOD proteins and identify members of the genetic network that function along with the ELMOD proteins in the specification of aperture domains.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.