Elucidation of the signalling pathway of deflagellation

阐明去鞭毛的信号通路

• 批准号: 227132-2011
• 负责人: Quarmby, Lynne
• 金额: $ 3.5万
• 依托单位: Simon Fraser University
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2015
• 资助国家: 加拿大
• 起止时间: 2015-01-01 至 2016-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=570245
• 关键词: Elucidation; signalling; pathway; deflagellation

The mechanism of deflagellation in the protist Chlamydomonas is the heart of my NSERC-funded research program. Surprisingly, these studies lead to discoveries of general relevance to eukaryotic cell cycle progression. Now, I propose to refocus on deflagellation, where there is every indication that we will make new discoveries of general import. Deflagellation is the shedding of flagella into the environment and is induced by cellular stress. The microtubule core of the flagellum is severed at its base, accompanied by resealing of the plasma membrane over the severed microtubules, thereby retaining the integrity of the cytoplasm. A deflagellated cell can regrow new flagella in ~90 minutes. One stress that causes deflagellation is pH shock, which we have shown works via intracellular acidification and activation of calcium influx at the base of the flagellum. Our genetic screen uncovered the adf1 mutants, which are defective in pH shock-induced deflagellation, but are wild-type for the calcium-activated machinery of microtubule severing. The ADF1 gene has not yet been cloned, but is predicted to encode either the acid-sensor or the calcium-permeant channel. Objective #1 is to identify ADF1 and elucidate its mode of action. We have shown that all of the components that are downstream of calcium in the deflagellation pathway are integral to the microtubule-based core of the flagellum. This result indicates that the severing module is a pre-existing protein complex that senses intracellular calcium and executes microtubule severing. Our genetic screen identified FA1 and FA2 as components of this complex. Objective #2 is to identify the remaining components and to elucidate the mechanism of action of this protein complex.

原生动物衣原体的爆燃机制是我NSERC资助的研究项目的核心。令人惊讶的是，这些研究导致了与真核细胞周期进程普遍相关的发现。 现在，我建议重新关注爆燃，在那里有各种迹象表明，我们将作出新的发现，一般进口。 脱鞭毛是鞭毛脱落到环境中，由细胞应激诱导。鞭毛的微管核心在其基部被切断，伴随着质膜在被切断的微管上重新密封，从而保持细胞质的完整性。爆燃的细胞可以在约90分钟内再生新的鞭毛。 引起爆燃的一种压力是pH休克，我们已经证明其通过细胞内酸化和激活鞭毛基部的钙内流起作用。我们的遗传筛选发现adf1突变体，这是有缺陷的pH冲击诱导的爆燃，但野生型的钙激活的微管切断机械。ADF1基因尚未被克隆，但预计编码酸传感器或钙渗透通道。目的#1是鉴定ADF 1并阐明其作用模式。 我们已经表明，在爆燃途径中的钙下游的所有组件是不可或缺的微管为基础的核心的鞭毛。 这一结果表明，切断模块是一个预先存在的蛋白质复合物，传感细胞内钙离子和执行微管切断。 我们的基因筛选确定FA 1和FA 2是该复合体的组成部分。目的#2是鉴定剩余的组分并阐明这种蛋白质复合物的作用机制。