Planar Cell Polarity and the Cytoskeleton

描述（由申请方提供）：平面细胞极性和细胞骨架平面细胞极性（PCP）信号传导调节上皮平面内极性的建立。信号的结果是多种多样的细胞命运的确定，不对称的，但高度对齐的结构（例如，静纤毛在人类内耳或苍蝇翅膀上的毛），或定向迁移的细胞在收敛延伸期间在脊椎动物原肠胚形成。PCP受非经典Fz/平面细胞极性途径控制，其中Wnt通过卷曲受体发出信号，导致核反应以及Rho激酶介导的细胞骨架变化。PCP信号最初是在果蝇中发现的，并且在果蝇中得到了最好的研究，主要是因为果蝇作为模型系统的多功能性，这是由于其低遗传冗余。在果蝇中，PCP对于肌动蛋白翼毛的方向和眼睛中小眼的极化是必不可少的，需要感光细胞组的高度协调运动（小眼旋转）。因此，在苍蝇中PCP信号的关键，并在脊椎动物的收敛延伸，是细胞骨架重排和细胞迁移过程。这些过程的核心是Rho激酶（Rock，果蝇中的Drok），其突变或显性失活形式分别导致果蝇和鱼类的小眼旋转/迁移和会聚延伸/神经管缺陷。该提案侧重于生物化学和遗传学方法，以确定和表征五氯苯酚的新成分和细胞骨架调节剂。在全基因组筛选中，我们使用磷酸化诱导的凝胶移位测定鉴定了直接Drok底物。我们将使用体内RNAi、突变分析和与已知途径组分的遗传相互作用测定来表征候选物。我们建议研究他们的行动机制方面的Rho激酶和PCP信号详细。使用上述策略来研究PCP信号传导的机制方面以及发现与细胞反应的新联系将扩展我们对早期发育的知识。由于五氯苯酚基因网络在苍蝇、海鞘和哺乳动物等多种生物体中保存完好，拟议的研究对于了解五氯苯酚在脊椎动物中的形成和相关形态发生过程具有直接的重要意义。公共卫生相关性：果蝇和人类细胞之间的通讯机制是非常保守和相似的。我们利用果蝇来研究细胞通讯如何影响细胞运动。缺乏这种沟通可能导致严重的出生缺陷，如开放性神经管（例如脊柱裂）。

DESCRIPTION (provided by applicant): Planar cell polarity and the cytoskeleton Planar cell polarity (PCP) signaling regulates the establishment of polarity within the plane of an epithelium. The results of signaling are as diverse as the determination of cell fates, the generation of asymmetric, but highly aligned structures (e.g. stereocilia in the human inner ear or hairs on a fly wing), or the directional migration of cells during convergent extension during vertebrate gastrulation. PCP is governed by the non-canonical Fz/Planar Cell Polarity pathway, in which a Wnt signals through a Frizzled receptor leading to nuclear responses, as well as to cytoskeletal changes mediated by Rho Kinase. PCP signaling was originally discovered and is best studied in Drosophila, mainly because of the versatility of the fly as model system due to its low genetic redundancy. In Drosophila, PCP is essential for the orientation of the actin wing hairs and the polarization of the ommatidia in the eye, requiring highly coordinated movement of groups of photoreceptor cells (ommatidial rotation). Thus, key to PCP signaling in flies, and to convergent extension in vertebrates, are cytoskeletal rearrangements and cell migration processes. Central to these processes is Rho Kinase (Rock, Drok in Drosophila), mutations in which or dominant negative forms of which lead to ommatidial rotation/migration and convergent extension/neural tube defects in flies and fish, respectively. This proposal focuses on biochemical and genetic approaches to identify and characterize new PCP components and regulators of the cytoskeleton. In a genome wide screen we identified direct Drok substrates using a phosphorylation induced gel-shift assay. We will characterize the candidates using in vivo RNAi, mutational analysis and genetic interaction assays with known pathway components. We propose to study their mechanism of action with respect to Rho Kinase and PCP signaling in detail. Using the above strategies to work out mechanistic aspects of PCP signaling as well as to discover new links to cellular responses will extend our knowledge of early development. Due to the conservation of the PCP gene network in organisms as diverse as flies, ascidians and mammals, the proposed research will be of immediate importance for the understanding of the establishment of PCP and related morphogenetic processes in vertebrates. PUBLIC HEALTH RELEVANCE: The mechanism of communication between cells of the fruitfly Drosophila and humans is well conserved and very similar. We make use of Drosophila to study how cell communication affects cell movement. Lack of such communication can lead to severe birth defects such as open neural tubes (e.g. spina bifida).