Regulation and functional characterization of ciliary calcium signaling

项目总结 第二信使钙如何调节像受精这样多种多样的信号过程， 增殖、发育、学习和记忆、收缩和分泌？隔室化钙 信号转导是钙离子在体内局部发挥刺激作用的基本信号转导原理。 精确控制空间和时间方式。细胞内局部钙浓度的变化是 通过跨质膜的钙离子进入来调节以产生“信号热点”或通过释放 CA2来自内质网(ER)、线粒体或内小体等细胞内储存。中的更改 钙离子浓度是由钙离子结合蛋白“感知”的，这些蛋白将信息传递到信号输出。 初级纤毛是由顶端质膜延伸而成的微管细胞器。 就像天线一样。初级纤毛富含钙离子渗透通道的一个特定子集，称为 多囊藻毒素(PC1和PC2)。虽然钙信号转导领域在理解 内质网和内体等细胞器内钙信号的分子机制 对于初级纤毛作为钙信号细胞器的功能仍缺乏了解。基因突变 多囊蛋白离子通道导致多种人类疾病，从先天性心脏病和 多脏器(肝、肾、胰腺)囊性形成的偏侧性缺陷。CA2很可能作为一种 在所有这些器官中，初级纤毛内的关键第二信使，但纤毛的功能后果 钙信号仍然是个谜，纤毛离子通道的机制也是如此 受监管的。这个项目的中心目标是了解纤毛离子通道PC1和PC2是如何调节的 并确定睫状肌钙信号传导的细胞生物学功能。 有三个具体目标。第一个目标是确定PC1/PC2通道活动如何影响睫状肌钙离子 集中精神。第二个目的是检验纤毛钙浓度的变化调节 初级纤毛底部的扩散屏障--过渡区蛋白质的通透性。第三 目的确定PC1的N-末端是如何被多个细胞修饰的3000个氨基酸的片段 粘附域，调节PC1/PC2离子通道活性。申请者的初步观察包括 记录PC1/PC2通道活性和动态调节睫状肌钙离子的新方法 集中精神。该项目的完成将是理解细胞生物学功能的关键的第一步。 纤毛钙信号。我们的长期目标是了解睫状肌钙动力学的失调是如何导致 人类纤毛病。

PROJECT SUMMARY How can the second messenger Ca2+ regulate a plethora of signaling processes as diverse as fertilization, proliferation, development, learning and memory, contraction and secretion? Compartmentalized Calcium signaling is a fundamental signaling principle by which Ca2+ ions exert their stimulatory function locally in a precisely controlled spatial and temporal manner. Changes in local Ca2+ concentration within the cell are regulated through Ca2+ entry across the plasma membrane to generate “signaling hot spots” or by releasing Ca2+ from intracellular stores such as endoplasmic reticulum (ER), mitochondria or endosomes. Changes in Ca2+ concentration are “sensed” by Ca2+ binding proteins which relay the information into a signaling output. The primary cilium is a microtubule based organelle extending from the apical plasma membrane and shaped like an antenna. Primary cilia are enriched in a specific subset of calcium permeating ion channels called polycystins (PC1 and PC2). While the Ca2+ signaling field has made seminal progress in understanding the molecular principles of compartmentalized Ca2+ signaling in organelles such as ER and endosomes, we are still lacking a functional understanding of the primary cilium as a Ca2+ signaling organelle. Mutations in polycystin ion channels result in a variety of human diseases, ranging from congenital heart disease and laterality defects to cyst formation in multiple organs (liver, kidney and pancreas). Ca2+ is likely to function as a critical second messenger within primary cilia in all of these organs, but the functional consequences of ciliary calcium signaling remain mysterious and so do the mechanisms through which ciliary ion channels are regulated. The central goal of this project is to understand how the cilia ion channels PC1 and PC2 regulate ciliary Ca2+ levels and to determine the cell biological function of compartmentalized ciliary Ca2+ signaling. There are three specific aims. The first aim is to determine how PC1/PC2 channel activity affects ciliary Ca2+ concentration. The second aim tests the hypothesis that changes in ciliary calcium concentration regulate the permeability for proteins of the transition zone, a diffusion barrier at the base of the primary cilium. The third aim determines how the N-terminus of PC1, a 3000 amino acid long fragment decorated with multiple cell adhesion domains, regulates PC1/PC2 ion channel activity. The applicants' preliminary observations include novel unpublished methods to r‐ecord PC1/PC2 channel activity and to dynamically regulate ciliary Ca2+ concentration. Completion of this project will be a critical first step in understanding the cell biological function ciliary calcium signaling. Our long term goal is to understand how dysregulation of ciliary Ca2+ dynamics cause human ciliopathies.