The Role of EPB41L5 in Regulation of Cilia Function

摘要 发育缺陷是导致美国和世界各地发病率和死亡率的重要因素。 虽然已经取得了相当大的进展，开始了解有助于 对于这些缺陷，很多人仍然知之甚少。我们研究细胞重排的形态发生。 细胞骨架组织，对周围环境的信号作出反应。这一过程中的缺陷 在胚胎发育过程中会导致出生缺陷和发育问题。我们的长期目标是 对形态发生的全面理解：细胞如何对来自环境和 在发育中的胚胎中重塑细胞骨架，其中细胞骨架的动态重排是 形态发生的主要驱动力。这对于增进我们对先天和先天疾病的理解是必不可少的 出生后的疾病，其中细胞骨架重排是缺陷的潜在来源。这项建议 本研究旨在探索红细胞膜蛋白带4.1样蛋白5(Epb4115)在糖尿病发病中的新作用。 睫毛功能的调节。纤毛是从顶端表面延伸出来的毛发状突起，用于接收信号。Epb41l5是 一种支架蛋白，能调节胞浆蛋白与质膜蛋白的结合。 Epb41l5调节一些需要肌动蛋白细胞骨架重塑的细胞过程，在 顶端皮质的特殊肌动蛋白。虽然先前的研究报告了epb4115缺失小鼠的纤毛功能障碍 胚胎，这些研究得出结论，纤毛的缺陷是继发于其他Epb41l5的缺陷。 顶端-基底端形成极性等功能。然而，我们的初步数据表明，Epb4115可能 对睫毛功能有直接的调节作用。我们建立了斑马鱼epb4115突变体的新等位基因。 它显示正常的根尖基极形成，但表现出与纤毛功能障碍相关的表型。 我们鉴定了肾囊藻毒素5(NHPH5)是一种新的Epb4115相互作用蛋白。NPHP5突变是 最初发现在肾炎患者和NPHP5已显示出调节纤毛功能。我们的 假说是：Epb4115通过抑制NPHP5在纤毛上的定位来调节睫状体功能。我们将测试 假设使用哺乳动物细胞培养系统和斑马鱼胚胎，建立脊椎动物的基因 在所有发育阶段都可以进行实验操作和成像的模型。完成 这项研究将有助于进一步了解睫状体功能的调节机制，这是 制定更有效的治疗策略来对抗纤毛病。我们认为，这项研究的成本很高 有效，并将产生数据，为未来的R01奠定基础。

Summary Developmental defects are substantial contributors to morbidity and mortality in the US as well as worldwide. While considerable progress has been made to begin to understand the underlying biology that contributes to these defects, much remains poorly understood. We study morphogenesis in which cells rearrange cytoskeletal organization in response to signals from its surrounding environments. Defects in this process during embryogenesis cause birth defects and developmental problems. Our long-term goal is a more comprehensive understanding of morphogenesis: how a cell responds to signals from its environment and remodels the cytoskeleton in developing embryos where dynamic rearrangement of the cytoskeleton is the major driving force of morphogenesis. This is essential to advance our understanding of congenital and postnatal disorders in which cytoskeletal rearrangement is the underlying source of the defect. This proposed research is aimed at exploring a novel role of Erythrocyte membrane protein band 4.1 like 5 (Epb41l5) in the regulation of ciliary function. Cilia are hair like extensions from the apical surface to receive signals. Epb41l5 is a scaffold protein that mediates association of cytosolic proteins with proteins at the plasma membrane. Epb41l5 regulates a number of cellular processes that require remodeling of the actin cytoskeleton, in particular actin at the apical cortex. While previous studies reported cilia dysfunction in epb41l5 null mouse embryos, these studies concluded that the defects in cilia were secondary to defects of other Epb41l5 functions such as apical-basal polarity formation. Our preliminary data, however, suggests that Epb41l5 could have a direct role in regulating ciliary function. We established novel alleles of zebrafish epb41l5 mutants which showed normal apicobasal polarity formation but showed phenotypes associated with cilia dysfunction. We identified Nephrocystin 5 (NHPH5) as a novel Epb41l5 interacting protein. NPHP5 mutations were originally identified in patients with Nephronophthisis and NPHP5 has shown to regulate cilia function. Our hypothesis is that: Epb41l5 regulates ciliary function by inhibiting NPHP5 localization at cilia. We will test the hypothesis using mammalian cell culture system and zebrafish embryos, an established vertebrate genetic model that is accessible for experimental manipulation and imaging at all developmental stages. Completion of this study will lead to further understanding of regulatory mechanisms of ciliary function, which is necessary for developing more effective therapeutic strategies to combat ciliopathies. We believe that this study is highly cost effective and will produce data that lays the basis for a future R01.