Polypeptides of the Flagellar Tip Complex

鞭毛尖端复合物的多肽

• 批准号: 6956486
• 负责人: ROGER D SLOBODA
• 金额: $ 15.99万
• 依托单位: DARTMOUTH COLLEGE
• 依托单位国家: 美国
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-09-01 至 2007-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6956486
• 关键词: Chlamydomonas; binding proteins; chickens; cystic kidney; disease /disorder etiology; flagellum; genetic manipulation; laboratory rabbit; microtubule associated protein; peptides; protein localization; protein protein interaction; protein quantitation /detection; protein structure function; protein transport; proteomics

DESCRIPTION (provided by applicant): Intraflagellar transport (IFT) is a process that is fundamental to the proper function of many cell types in the body, among them cells of the kidney where it is required for the assembly and maintenance of the primary cilia of the cells lining the nephron. Defects in the components of these primary cilia and defects in the machinery of IFT have been shown to cause polycystic kidney disease. The long term goals of this new project are to identify and characterize proteins of the flagellar tip complex and learn how they are involved in controlling particle movement during IFT. Why direct these studies to the flagellar tip? The microtubules (MTs) of the flagellar axoneme assemble and continuously turn over at the flagellar tip. The supply to and removal from the flagella of IFT components requires two motors: the MT-based motor protein kinesin-ll moves cargo from the base to the tip, and cytoplasmic dynein 1b moves cargo from the tip back to the base. Important activities relevant to the proper functioning of IFT occur at the flagellar tip, and these include MT assembly and disassembly, motor protein regulation, and cargo loading and unloading. Because an abrupt change in the direction of particle movement occurs only at the flagellar tip, the motor proteins must be regulated at the tip. Kinesin must be down regulated or turned off, and cytoplasmic dynein must be upregulated or turned on. The mechanisms used to control motor protein regulation and cargo unloading at the tip are unknown, but it is likely that a complex of proteins restricted to the flagellar tip, herein referred to as the flagellar tip complex (FTC), plays a definitive role in these processes. To test this hypothesis, three aims are proposed here: Having identified a polypeptide, CrEB1, that is localized at the flagellar tip. I will use rEB1 as a hook to fish out and identify other FTC proteins that are specific to the flagellar tip. The second aim will employ different approaches to identify structural and enzymatic components of the FTC that do not depend on an interaction with CrEBl. The third aim will characterize the FTC proteins identified via the first two aims and determine their function in IFT. Understanding more about the process of IFT is very important, as recent studies have shown that IFT defects cause polycystic kidney disease specifically, and defects in primary cilia are associated with a range of human disorders in addition to cystic diseases of the kidney, including retinal degeneration, obesity, hypertension, and diabetes, etc.

描述（由申请人提供）：鞭毛内转运（IFT）是体内许多细胞类型正常功能的基础过程，其中包括肾脏细胞，其中需要组装和维持肾单位内衬细胞的初级纤毛。这些初级纤毛成分的缺陷和IFT机制的缺陷已被证明会导致多囊肾病。这个新项目的长期目标是识别和表征鞭毛尖端复合物的蛋白质，并了解它们如何参与控制IFT过程中的粒子运动。为什么要把这些研究指向鞭毛尖端呢？鞭毛轴丝的微管在鞭毛顶端不断地组装和翻转。IFT组分的鞭毛的供应和移除需要两个马达：基于MT的马达蛋白驱动蛋白-II将货物从基部移动到尖端，而细胞质动力蛋白1b将货物从尖端移动回基部。 与IFT正常功能相关的重要活动发生在鞭毛尖端，这些活动包括MT组装和拆卸、马达蛋白调节以及货物装载和卸载。由于粒子运动方向的突然变化只发生在鞭毛尖端，因此马达蛋白必须在尖端受到调节。驱动蛋白必须被下调或关闭，细胞质动力蛋白必须被上调或打开。用于控制马达蛋白调节和货物卸载在尖端的机制是未知的，但它可能是一个复杂的蛋白质限制在鞭毛尖端，本文称为鞭毛尖端复合物（FTC），在这些过程中发挥决定性的作用。为了验证这一假设，这里提出了三个目标：已经确定了一种多肽，CrEB 1，这是本地化的鞭毛尖端。我将使用rEB 1作为钩来钓出并识别鞭尖特异性的其他FTC蛋白。第二个目标将采用不同的方法来鉴定不依赖于与CrEBl相互作用的FTC的结构和酶组分。 第三个目标将表征通过前两个目标鉴定的FTC蛋白，并确定它们在IFT中的功能。了解更多关于IFT的过程是非常重要的，因为最近的研究表明，IFT缺陷特别导致多囊肾疾病，并且初级纤毛缺陷与除了肾脏囊性疾病之外的一系列人类疾病相关，包括视网膜变性，肥胖，高血压和糖尿病等。