The role of molecular chaperones in mammalian primary cilia structure and function

人体的许多细胞都有感觉触角，称为初级纤毛，从它们的表面伸出。初级纤毛的功能是帮助细胞感知它们的环境，并与将细胞外环境的变化传达给其他细胞的分子通路相关联。初级纤毛在许多不同的系统中发挥作用，并且对于感知外部环境和维持生物体内的稳态（身体系统的平衡）都很重要。例如，在负责嗅觉的细胞表面上，气味受体位于初级纤毛上;此外，它们对于视觉是必不可少的，作为感光细胞，眼睛后部的细胞类型检测光，具有专门的初级纤毛结构。初级纤毛也可以在肾脏中的小管内衬细胞的表面上发现，在那里它们检测液体的流动。毫不奇怪，受损的初级纤毛结构和/或功能可导致诸如失明和肾病的疾病。最近，人们也认识到，初级纤毛功能的缺陷可能与更常见的健康问题有关，如肥胖，糖尿病和高血压。因此，重要的是要充分了解初级纤毛如何工作，以及它们的构建和维护过程。本申请旨在阐明这些方法。蛋白质是基本的生物分子，它构建了允许身体功能的机器。大多数蛋白质在多蛋白质复合物中起作用。关于哪些蛋白质可能在初级纤毛功能中发挥作用的线索来自一系列实验技术，包括疾病模型和筛选，这些技术试图定义运动纤毛（另一种类型的纤毛，具有不同的内部结构和执行不同的功能）中存在的所有蛋白质。被称为分子伴侣的一类蛋白质的成员一直被认为对正常纤毛功能很重要。分子伴侣帮助其他蛋白质执行其功能。分子伴侣的一个关键细胞作用是帮助其他蛋白质组装成多蛋白质复合物。我假设分子伴侣是重要的组装这种多蛋白复合物在初级纤毛。该建议旨在确定哪些分子伴侣存在于初级纤毛中并定义其作用。分子伴侣不是孤立地发挥作用，而是在分子“机器”中一起工作。Hsp 70分子伴侣机器的多个组件被预测存在于初级纤毛中，并且我们将关注于该分子伴侣系统。为了了解更多关于热休克蛋白70分子伴侣机制和了解它在初级纤毛中的作用，我们将进行一系列综合实验。这些将识别初级纤毛中存在哪些分子伴侣、它们在结构中的精确位置、它们与哪些蛋白质相互作用以及当它们缺失时初级纤毛会发生什么。完成这些目标将促进我们对分子伴侣的细胞作用的理解。它还将鉴定对初级纤毛功能重要的蛋白质;其中一些可能对人类疾病重要和/或代表人类疾病如肥胖症的治疗干预的靶点。

Many cells in the human body have sensory antennae, known as primary cilia, projecting from their surface. Primary cilia function to help cells sense their environment and are linked to molecular pathways which communicate changes in the extra-cellular environment to other cells. Primary cilia play a role in many different systems and are important for sensing both the external environment and maintaining homeostasis (equilibrium of the bodies systems) within the organism. For example, on the surface of cells responsible for smell, odour receptors are located at the primary cilia; furthermore they are essential for vision as photoreceptor, the cells type at the back of the eye which detect light, have a specialised primary cilia structure. Primary cilia are also found on the surface of cells lining tubules in the kidney where they detect the flow of fluid. Unsurprisingly compromised primary cilia structure and/or function can cause disorders such as blindness and kidney disease. Recently it has also been recognised that defects in primary cilia function may be linked to much more common health problems such as obesity, diabetes and high blood pressure. Thus it is important to fully understand how primary cilia work and the processes involved in their construction and maintenance. This application aims to elucidate such processes. Proteins are the essential biological molecules that build the machines which allow the body function. Most proteins work in multi-protein complexes. Clues as to which proteins may play a role in primary cilia function have come from a range of experimental techniques including models of disease and screens that have attempted to define all of the proteins present in motile cilia (another type of cilia which have a different internal structure and perform different functions). Members of a class of proteins known as molecular chaperones have consistently been identified as important for normal cilia function. Molecular chaperones help other proteins perform their functions. One key cellular role of molecular chaperones is to help other proteins assemble into multi-protein complexes. I hypothesise that molecular chaperones are important for assembly of such multi-protein complexes in primary cilia. This proposal aims to identify which molecular chaperones are present in primary cilia and define their roles. Molecular chaperone do not function in isolation, but work together in molecular 'machines'. Multiple components of the Hsp70 molecular chaperone machine are predicted to be present in primary cilia and it is on this molecular chaperone system that we will focus. To find out more about the Hsp70 molecular chaperone machinery and understand what it does in primary cilia we will perform a comprehensive series of experiments. These will identifying which molecular chaperones are present in primary cilia, where precisely they are located in the structure, which proteins they interact with and what happens to primary cilia when they are absent. Completing these goals will advance our understanding of the cellular roles of molecular chaperones. It will also identify proteins which are important for primary cilia function; some of these may be important for human disease and/or represent targets for therapeutic intervention in human disease such as obesity.