Calcium regulation of flagellar motility

描述（由申请人提供）：本项目的目标是了解钙改变纤毛和鞭毛弯曲的大小和形状以控制运动的机制。在哺乳动物中，运动的纤毛/鞭毛是精子推进、从呼吸道清除碎片、脑脊液循环甚至在发育期间决定左右身体计划所必需的。因此，运动缺陷可能导致生育能力受损、呼吸窘迫、脑积水和/或左右体轴随机化。构成这些细胞器的结构和分子是非常保守的。因此，从任何单细胞类型的研究中获得的运动性的基本原理通常适用于所有真核纤毛和鞭毛。了解动力蛋白是如何调节产生复杂的波形，典型的纤毛/鞭毛的跳动仍然是最紧迫的纤毛运动领域的悬而未决的问题。大量的数据有助于一个模型，其中轴丝微管作为一个支架的组装分子，形成一个信号转导途径，最终调节动力蛋白。第二信使钙影响这些信号转导通路，以改变响应细胞外信号的搏动。钙调素（CaM）是一个关键的钙传感器，高度保守的钙调素结合蛋白定位于轴丝结构，已知在运动中发挥作用的发现形成这项工作的基础。所提出的实验旨在测试特定的钙调素结合蛋白是信号转导网络的一部分，改变运动响应钙的假设。本提案的具体目的是：1）开发具有CaM相互作用物缺陷的菌株; 2）检验中枢装置相关CaM在调节特定双联体微管上的动力蛋白活性中发挥作用的假设; 3）检验辐条相关CaM结合复合物CSC是调节动力蛋白活性的信号转导途径的结构和功能组分的假设。这些研究有可能定义钙调素介导的信号转导的分子机制，包括特定的蛋白质-蛋白质相互作用作为开关来控制动力蛋白活性，以及更广泛的潜力，定义新的原则，为目标和锚定的分子，定义信号转导途径，调节动力蛋白家族的电机。 公共卫生相关性：我们感兴趣的是确定纤毛和鞭毛运动的钙调节机制。在哺乳动物中，运动纤毛/鞭毛是精子推进、从呼吸道清除碎片、脑脊液循环甚至在发育期间确定左右身体计划所必需的（在Satir和Christensen，2006中综述）。因此，运动缺陷可能导致生育能力受损、呼吸窘迫、脑积水和/或左右体轴随机化（综述见Badano et al，2006）。

DESCRIPTION (provided by applicant): The goal of this project is to understand the mechanism by which calcium alters the size and shape of ciliary and flagellar bends to control motility. In mammals, motile cilia / flagella are required for sperm propulsion, removal of debris from the respiratory tract, circulation of cerebrospinal fluid, and even for determination of the left-right body plan during development. As a consequence, defects in motility may result in impaired fertility, respiratory distress, hydrocephalus, and/or randomization of the left-right body axis. The architecture and molecules which comprise these organelles are remarkably conserved. Therefore, fundamental principles for motility obtained from studies of any single cell type are generally applicable to all eukaryotic cilia and flagella. Understanding how dynein is regulated to produce the complex waveforms typical of beating cilia / flagella is still the most pressing unanswered question in the field of ciliary motility. Substantial data has contributed to a model in which the axonemal microtubules act as a scaffold for the assembly of molecules that form a signal transduction pathway that ultimately regulates dynein. The second messenger calcium impacts upon these signal transduction pathways to alter beating in response to extracellular cues. The discovery that calmodulin (CaM) is a key calcium sensor and that highly conserved CaM-binding proteins are localized to axonemal structures known to play a role in motility form the foundation for this work. The proposed experiments are designed to test the hypothesis that specific CaM-binding proteins are part of a signal transduction network that alters motility in response to calcium. The Specific Aims of this proposal are to 1) develop strains with defects in CaM interactors; 2) test the hypothesis that central apparatus associated CaM plays a role in modulating dynein activity on specific doublet microtubules; and 3) test the hypothesis that a spoke-associated CaM binding complex, the CSC, is both a structural and functional component of a signal transduction pathway that modulates dynein activity. These studies have the potential to define a molecular mechanism for CaM mediated signal transduction that includes specific protein-protein interactions acting as switches to control dynein activity, as well as the broader potential to define new principles for the targeting and anchoring of molecules that define signal transduction pathways that regulate the dynein family of motors. PUBLIC HEALTH RELEVANCE: We are interested in defining mechanisms for calcium regulation of ciliary and flagellar motility. In mammals, motile cilia / flagella are required for sperm propulsion, removal of debris from the respiratory tract, circulation of cerebrospinal fluid, and even for determination of the left-right body plan during development (reviewed in Satir and Christensen, 2006). As a consequence, defects in motility may result in impaired fertility, respiratory distress, hydrocephalus, and/or randomization of the left-right body axis (reviewed in Badano et al, 2006).