Calcium regulation of flagellar motility

钙对鞭毛运动的调节

• 批准号: 6679762
• 负责人: Elizabeth F Smith
• 金额: $ 27.65万
• 依托单位: DARTMOUTH COLLEGE
• 依托单位国家: 美国
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-08-01 至 2008-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6679762
• 关键词: Chlamydomonas; biological signal transduction; calcium binding protein; calcium flux; calmodulin; calmodulin dependent protein kinase; cell component structure /function; centrosome; cilium /flagellum motility; dynein ATPase; flagellum; microtubules; protein localization; tissue /cell culture

DESCRIPTION (provided by applicant): The long-range goal of this project is to determine the mechanism by which the molecular motor dynein is regulated to produce the complex waveforms characteristic of beating eukaryotic cilia and flagella. The proposed research is specifically aimed at understanding how changes in calcium modulate the size and shape of ciliary and flagellar bends to control motility. Several studies have indicated that the flagellar central apparatus is a key component of a signal transduction pathway that regulates dynein activity to modulate waveform. The objectives of this proposal are founded on the hypothesis that the central apparatus locally controls a calcium sensor to regulate dynein activity, and that calmodulin and an axonemal calmodulin dependent kinase mediate the calcium signal. The proposed experiments are designed to test this hypothesis and to identify axoneme components involved in the calmodulin-mediated signal transduction pathway. The Specific Aims are: 1) to identify calmodulin-binding proteins associated with the central apparatus; 2) to characterize calmodulin dependent kinases associated with the axoneme; and 3) to determine if the activities of particular dynein subforms attached to specific subsets of doublet microtubules are preferentially modulated by changes in calcium. The unicellular green alga, Chlamydomonas reinhardtii, is the organism of choice for these studies as it is the only system that offers motility mutants, virtually unlimited material for biochemical approaches, and unique in vitro functional assays. Many of the genes encoding flagellar proteins in Chlamydomonas show high sequence similarity with genes in the human genome and EST databases. Therefore, the information obtained in Chlamydomonas will be directly applicable to higher eukaryotes and may provide insight into defects that result in primary cilia dyskinesia including Kartegener's syndrome. Studies of dynein regulation and control of flagellar waveform will also impact upon our understanding of certain developmental processes. For example, the nodal cilia in developing embryos have been implicated in the production of a morphogen gradient responsible for generating left-right asymmetry. This result explains the observation that about 50% of patients with immotile-cilia syndrome also have situs inversus. Interestingly, nodal cilia utilized during development do not assemble a central apparatus and beat with a different waveform than cilia of epithelial cells found in the same organism. This observation further illustrates the importance of controlling ciliary and flagellar waveforms appropriate for particular cell types.

描述（由申请人提供）：该项目的远程目标是确定分子运动动力蛋白的调节以产生击败真核纤毛和鞭毛的复杂波形的特征的机制。拟议的研究专门旨在了解钙的变化如何调节睫状和鞭毛弯曲的大小和形状以控制运动。几项研究表明，鞭毛中央设备是信号转导途径的关键组成部分，该途径调节动力蛋白活性调节波形。该提案的目标建立在以下假设上：中央设备局部控制钙传感器以调节动力蛋白活性，而钙调蛋白和轴突钙调蛋白依赖蛋白依赖性激酶介导钙信号。所提出的实验旨在检验该假设，并确定参与钙调蛋白介导的信号转导途径的轴突成分。这 具体目的是：1）鉴定与中央设备相关的钙调蛋白结合蛋白； 2）表征与轴突相关的钙调蛋白依赖性激酶； 3）为了确定连接到双重微管特定子集附加的特定动力蛋白的活性优先通过钙的变化来调节。单细胞绿藻（Chlamydomonas reinhardtii）是这些研究的首选有机体，因为它是唯一提供运动突变体的系统，几乎无限的生化方法材料以及独特的体外功能分析。 编码衣原体中编码鞭毛蛋白的许多基因表现出与人基因组和EST数据库中基因的高序列相似性。因此，在衣原体中获得的信息将直接适用于更高的真核生物，并可能提供对导致主要纤毛运动障碍（包括Kartegener综合征）的缺陷的见解。对鞭毛波形的调节和控制的研究也将影响我们对某些发育过程的理解。例如，发育胚胎中的节点纤毛与产生左右不对称的形态梯度的产生有关。该结果解释了以下观察结果：大约50％的Immotile-Cilia综合征患者也患有SITUS Inversus。有趣的是，在发育过程中使用的结节纤毛不会组装一个中央设备，并以与同一生物体中的上皮细胞的纤毛纤毛不同。该观察结果进一步说明了控制适合特定细胞类型的睫状波和鞭毛波形的重要性。