Structural basis of dynein-driven ciliary motility

摘要： 纤毛和鞭毛是进化上保守的类似附属器的细胞器，它们感觉 细胞外环境，驱动单个细胞的运动，或运输液体。睫状体缺陷症 功能导致许多称为纤毛病的疾病，这些疾病导致各种先天性 并引起广泛的症状。外臂动力蛋白(OAD)是一种关键的运动 产生最大机械力的蛋白质，通过三磷酸腺苷的水解为纤毛跳动提供动力。OAD 在超过一半的原发性睫状体运动障碍(PCD)患者中发现了突变。这些突变 在藻类和纤毛虫中有同源基因，这也会导致纤毛/鞭毛功能障碍，这表明 低等物种和人类在纤毛运动机制上有重要的共同点。 然而，缺乏大多数睫毛成分的原子模型一直是我们 了解纤毛系统。我们将使用T.thermophila和C.reinhardtii模型系统来 阐明纤毛组装和动力蛋白驱动的纤毛运动在接下来的几年中，重点 关于OAD及其监管。我们的目标是通过结合以下几种原子细节来揭示这些机制 低温EM/ET，相关光电子显微镜(CLEM)，生物化学，细胞生物学，单细胞 分子生物物理学和计算模型等。我们在接下来几年的目标是 了解OAD阵列是如何在纤毛中形成的，OAD在击打过程中如何相互协调， 其他纤毛成分(如中央对)和细胞外如何调节OAD活性 信号，并建立轴丝的原子模型。我们将共同开发冷冻-EM/ET方法来解决 长期存在的问题。所揭示的机制将为我们的 未来在哺乳动物系统和人类疾病模型中的突变。

Summary: Cilia and flagella are evolutionarily conserved appendage-like organelles that sense the extracellular environment, drive the movement of individual cells, or transport fluids. Defects of ciliary functions lead to numerous diseases termed the ciliopathies, which result in a variety of congenital disorders and cause a broad spectrum of symptoms. The outer-arm dynein (OAD) is a key motor protein that generates most mechanical forces to power the ciliary beating by ATP hydrolysis. OAD mutations were found in over half of the primary ciliary dyskinesia (PCD) patients. These mutations have orthologs in algae and ciliates, which also lead to cilia/flagellar dysfunctions, suggesting that the lower species and humans have important commonalities on the mechanisms of ciliary motility. However, lacking an atomic model of most ciliary components has been a main barrier to our understanding the cilium system. We will use the model systems T. thermophila and C. reinhardtii to elucidate the cilium assembly and dynein-driven ciliary motility in the following years, with an emphasis on OAD and its regulation. We aim to reveal the mechanisms in atomic details by a combination of cryo-EM/ET, correlative light and electron microscopy (CLEM), biochemistry, cell biology, single- molecule biophysics, and computational modeling etc. Our aims for the following years are to understand how OAD arrays are formed in cilia, how OADs coordinate with each other during beating, how the OAD activity is regulated by other ciliary components (such as central pair) and extracellular signals, and build an atomic model of axoneme. We will co-develop cryo-EM/ET methods to address long-standing problems. The revealed mechanisms will provide more accurate information for our future mutagenesis in mammalian systems and human disease models.