Mechanisms of microridge protrusion morphogenesis on mucosal epithelial cells

项目摘要 基于肌动蛋白的突起赋予细胞各种各样的形式。粘膜上皮表面细胞 诸如角膜和口腔的组织，经常伸出细长的、类似于矛状的突起，称为微脊， 其以迷宫状图案排列在顶端表面上。微脊帮助这些细胞保留粘液， 保护脆弱的上皮组织免受感染、磨损和干燥。直到最近，几乎没有 关于微脊形态发生的知识由于微脊形态不同于那些更好的- 研究突起，研究它们可以揭示突起形态发生的基本新原理。 近年来，Sagasti实验室建立了幼斑马鱼皮肤细胞作为研究微脊的模型 形态发生该模型能够实现强大的分子操作和形态发生的实时成像。 Sagasti实验室的初步研究揭示了几个新发现，包括：1）微脊的解剖 形态发生分为四个分子上可分离的步骤，2）发现，在顶端肌球蛋白收缩， 皮质调节表面张力以允许微脊形成，3）Plakin细胞连接物的鉴定， 微脊长度的主要调节者，4）发现角蛋白丝是微脊长度的组成部分， 微脊对于它们的稳定性和伸长率是必需的（中间长丝的第一个例子直接 有助于突起形态发生），以及5）发现皮质肌球蛋白微丝协调 一种不寻常的微脊裂变/聚变重排过程，有助于形成规则的，周期性的 细胞表面的微脊排列。总的来说，这些发现对如何 皮质肌球蛋白、细胞连接体和中间丝有助于突起形态发生。 在这些成就和新的初步数据的基础上，Sagasti实验室将继续研究两条未来的生产线， research.首先，由于皮质收缩创造了生物力学条件， 形态发生，他们将研究如何交联蛋白和细胞连接时间和空间调整 皮质收缩，以促进微脊形成和图案化。由于皮质收缩控制了许多 这些实验将揭示与细胞生物学广泛相关的调控机制。 其次，由于Plakin细胞连接物是微脊起始和延伸的中心调节物，它们将 研究Plakins的结构如何与它们在微脊形态发生中的功能作用相关，并使用 Plakin蛋白作为识别细胞骨架支架的新调节组分的手柄， 微脊突起。

PROJECT SUMMARY Actin-based protrusions endow cells with a vast variety of forms. Cells on the surface of mucosal epithelial tissues, such as the cornea and mouth, often project elongated, wrinkle-like protrusions called microridges, which are arranged on apical surfaces in maze-like patterns. Microridges help these cells retain mucus, thus protecting vulnerable epithelial tissues from infection, abrasion and drying out. Until recently, almost nothing was known about microridge morphogenesis. Since microridge morphologies are distinct from those of better- studied protrusions, studying them could reveal fundamental new principles of protrusion morphogenesis. In recent years, the Sagasti lab established larval zebrafish skin cells as a model for studying microridge morphogenesis. This model enables powerful molecular manipulations and live imaging of morphogenesis. The Sagasti lab’s initial studies revealed several new discoveries, including: 1) The dissection of microridge morphogenesis into four molecularly separable steps, 2) the discovery that myosin contraction in the apical cortex regulates surface tension to permit microridge formation, 3) the identification of Plakin cytolinkers as master regulators of microridge length, 4) the discovery that keratin filaments are integral components of microridges required for their stability and elongation (the first example of intermediate filaments directly contributing to protrusion morphogenesis), and 5) the discovery that cortical myosin minifilaments orchestrate an unusual microridge fission/fusion rearrangement process that facilitates the formation of regular, periodic microridge arrangements on cell surfaces. Collectively, these discoveries have broad implications for how cortical myosin, cytolinkers, and intermediate filaments contribute to protrusion morphogenesis. Building on these achievements and new preliminary data, the Sagasti lab will pursue two future lines of research. First, since cortical contractility creates the biomechanical conditions enabling microridge morphogenesis, they will investigate how cross-linking proteins and cell junctions temporally and spatially tune cortical contractility to promote microridge formation and patterning. Since cortical contractility controls many cellular processes, these experiments will reveal regulatory mechanisms with wide relevance in cell biology. Second, since Plakin cytolinkers are central regulators of microridge initiation and elongation, they will investigate how the structure of Plakins relate to their functional roles in microridge morphogenesis, and use Plakin proteins as handles for identifying new regulatory components of the cytoskeletal scaffold that creates microridge protrusions.