Identifying Signaling Mechanisms Controlling Flagellar Length in Chlamydomonas

描述（由申请人提供）：纤毛是从大多数哺乳动物细胞表面突出的基于微管的细胞器，其功能范围从调节身体对称性到感觉功能。纤毛的形成和维持的异常往往由于这些细胞器的几乎无处不在而具有不同的病理后果。纤毛的结构和组装是高度保守的，并且在单细胞绿色莱茵衣藻的运动鞭毛中很容易进行研究。这些细胞上鞭毛的长度对细胞外和细胞内环境高度敏感。了解参与感知异常和响应长度变化的信号传导机制，以及了解参与内在长度确定的机制对于确定纤毛相关病理的来源至关重要。为了解决这个中心问题，我将首先确定在鞭毛组装过程中不受调节的未表征的信号分子的功能，包括GPCR和含脂肪酶结构域的蛋白质FAP 12。我还将研究已知的长度调节蛋白LF 1 p，LF 2 p，LF 3 p和LF 4p的复杂相互作用，以确定它们如何相互作用，以严格控制鞭毛长度。最后，我将确定新的组件在这一途径中使用的插入诱变筛选抑制长鞭毛突变体。 公共卫生相关性：识别和表征可以控制几乎无处不在的纤毛细胞器的长度的信号分子将使我们对由异常纤毛大小引起的纤毛病有重要的了解。具体而言，测试纤毛长度调节复合物的特定作用并确定调节长度的途径中的新组分将为广泛的纤毛病的治疗干预提供许多新的潜在靶点。这些纤毛病变包括多囊肾病、肾单位营养不良、Bardet-Biedl综合征、脑积水、视网膜变性和许多其他疾病。

DESCRIPTION (provided by applicant): Cilia are microtubule-based organelles that protrude from the surface of most mammalian cells for functions ranging from regulating body symmetry to sensory functions. Abnormalities in formation and maintenance of cilia often have variable pathologic consequences due to the near-ubiquity of these organelles. The structure and assembly of cilia are highly conserved and are readily studied in the motile flagella of the unicellular green alga Chlamydomonas reinhardtii. The length of flagella on these cells is highly responsive to the extracellular and intracellular environment. Understanding the signaling mechanisms involved in sensing abnormalities and responding with changes in length, as well as understanding the mechanisms involved in intrinsic length determination are critically important for identifying sources of cilia related pathology. To tackle this central question, I will first identify the function of uncharacterized signaling molecules that are unregulated during flagellar assembly including a GPCR and a lipase domain containing protein, FAP12. I will also investigate the complex interactions of known length-regulating proteins LF1p, LF2p, LF3p and LF4p to determine how they act with one another for tight control of flagellar length. Finally I will identify novel components in this pathway using an insertional mutagenesis screen for suppressors of a long flagella mutant. PUBLIC HEALTH RELEVANCE: Identifying and characterizing signaling molecules that can control the length of the nearly ubiquitous ciliary organelle will give us significant insights into the ciliopathies that result from abnormal cilium size. Specifically, testing the specific role of cilia length regulation complexes and identifying novel components in pathways regulating length will provide many new potential targets for therapeutic intervention in a wide range of ciliopathies. These ciliopathies include polycystic kidney disease, nephronophthisis, Bardet-Biedl syndrome, hydrocephalus, retinal degeneration and many others.