Novel Cilia Trafficking Mechanisms

新颖的纤毛贩运机制

• 批准号: 7753753
• 负责人: BENJAMIN L MARGOLIS
• 金额: $ 35.09万
• 依托单位: UNIVERSITY OF MICHIGAN AT ANN ARBOR
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-09-28 至 2011-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7753753
• 关键词: Affect; Apical; Binding; Binding Proteins; Cell Nucleus; Cell division; Cells; Centrosome; Cilia; Cyst; Cystic Kidney Diseases; Epithelial Cells; Etiology; Guanosine Triphosphate; Heart; Importins; Integral Membrane Protein; Kidney; Kidney Failure; Laboratories; Liquid substance; Mammalian Cell; Mediating; Molecular; Monomeric GTP-Binding Proteins; Movement; Mutation; Nuclear; Nuclear Export; Nuclear Import; Organelles; Play; Polycystic Kidney Diseases; Protein Import; Protein Isoforms; Proteins; RNA Splicing; Regulation; Retinitis Pigmentosa; Role; Running; Structure; Surface; System; Testing; Transmembrane Domain; Travel; Work; alpha Karyopherins; base; cilium biogenesis; insight; kinetosome; novel; protein transport; public health relevance; trafficking

DESCRIPTION (provided by applicant): Recent evidence implicates cilia abnormalities as important in the etiology of Polycystic Kidney Disease. Our laboratory has defined an important role for polarity proteins, such as the apical transmembrane protein Crumbs3, in ciliogenesis. In the course of our study on Crumbs3, we have identified a novel cilia and centrosomal trafficking mechanism that involves the Ran/Importin system. Ran is a small GTPase that is concentrated in the nucleus and regulates the import of proteins into the nucleus in combination with Importins. Importins travel into the nucleus carrying their cargo and when they bind to RanGTP, the cargo is released leading to overall nuclear import. However Ran is also concentrated at other points in the cell including the centrosome. We have found that Importin beta1 can bind to a splice form of Crumbs3, called Crumbs3-CLPI, and target this isoform of Crumbs to the centrosome. We also have obtained evidence that another cilia protein, called RP2, also uses the Importin system for trafficking to the cilia. Our hypothesis that guides this proposal is that the Ran/Importin system plays a major role in regulation of cilia and centrosomal trafficking. To test this hypothesis, we propose three specific aims. The first specific aim will be to identify the molecular basis for the Crumb3-CLPI interaction with Importins and determine how mutations that alter this interaction affect the trafficking of this isoform of Crumbs3. The second specific aim will test the role of other Importins, including Importin alphas, in this trafficking mechanism and in cilia function in general. In the last specific aim we will manipulate the levels of RanGTP at the centrosome and determine the effect of this manipulation on centrosome and cilia trafficking. We will also work to identify Ran and Importin alpha binding proteins at the centrosome. At the conclusion of these studies we will have a greater understanding of the role of the Ran/Importin system in cilia trafficking networks. This will have important implications for our understanding of Polycystic Kidney Disease and other ciliopathies. PUBLIC HEALTH RELEVANCE: The aim of this proposal is to study mechanisms that control the movements of proteins into a cell organelle called the cilia. Recent studies have suggested that defective function of the cilia leads to cystic diseases of the kidney. Cystic diseases of the kidney, where the normal kidney is replaced by non-functioning fluid filled cysts, are a major cause of kidney failure.

描述（由申请人提供）：最近的证据暗示纤毛异常在多囊肾脏病的病因中很重要。我们的实验室在纤毛发生中定义了极性蛋白的重要作用，例如顶跨膜蛋白Crumbs3。在Crumbs3的研究过程中，我们确定了一种涉及RAN/Importin系统的新型纤毛和中心贩运机制。 RAN是一个小的GTPase，它集中在细胞核中，并与进口素结合调节蛋白质中的进口到核中。 Importins进入载有货物的细胞核中，当它们与Rangtp结合时，该货物将释放，从而导致整体核进口。但是，RAN也集中在细胞中的其他点，包括中心体。我们发现，importin beta1可以与Crumbs3的剪接形式结合，称为Crumbs3-ClPi，并将其靶向Crumbs的同工型与中心体。我们还获得了证据，表明另一种称为RP2的纤毛蛋白也使用intermin系统进行贩运纤毛。我们指导该提议的假设是，RAN/Importin系统在调节Cilia和Centrosomal贩运方面起着重要作用。为了检验这一假设，我们提出了三个具体目标。第一个具体目的是确定CRUMB3-CLPI与Importins相互作用的分子基础，并确定改变这种相互作用的突变如何影响Crumbs3同工型的运输。第二个特定目的将测试其他进口素的作用，包括Importin Alpha，在该运输机制和整个Cilia功能中的作用。在最后一个特定目的中，我们将操纵中心体的rangtp水平，并确定这种操纵对中心体和纤毛贩运的影响。我们还将努力识别中心体的RAN和Importin Alpha结合蛋白。在这些研究的结论中，我们将对RAN/Import System在CILIA贩运网络中的作用有更深入的了解。这将对我们对多囊性肾脏疾病和其他纤毛病的理解具有重要意义。公共卫生相关性：该提案的目的是研究控制蛋白质向细胞细胞器的运动的机制，称为纤毛。最近的研究表明，纤毛的功能有缺陷导致肾脏的囊性疾病。肾脏的囊性疾病是肾衰竭的主要原因。