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.

prion虫衣原体中偏花的机制是我由NSERC资助的研究计划的核心。令人惊讶的是，这些研究导致发现与真核细胞周期进程的普遍相关性。 现在，我建议重新集中于faflagellation，其中有一切迹象表明我们将对一般进口进行新的发现。 feflagellation是将鞭毛脱落到环境中，并由细胞应激诱导。鞭毛的微管芯在其底部切断，并伴随着质膜在切断的微管上的重新密封，从而保留了细胞质的完整性。降低的细胞可以在〜90分钟内再生新的鞭毛。 引起fefagellation的一种压力是pH冲击，我们已经通过细胞内酸化和钙液体在鞭毛底部激活钙流入的作用。我们的遗传屏幕发现了ADF1突变体，该突变体在pH冲击引起的缩水中有缺陷，但对于微管切断的钙激活机械而言是野生型。 ADF1基因尚未克隆，但预计将编码酸性传感器或钙 - permeant通道。目标＃1是识别ADF1并阐明其作用方式。 我们已经证明，在鞭毛途径中钙下游的所有组件都是基于微管的鞭毛核心不可或缺的。 该结果表明，切断模块是一种先前存在的蛋白质复合物，可感知细胞内钙并执行微管断裂。 我们的遗传屏幕将FA1和FA2识别为该复合物的组成部分。目标＃2是确定其余成分，并阐明该蛋白质复合物的作用机理。