Investigation of the molecular chaperone HSP90 in arabidopsis: its function in plant development, organelle physiology and biogenesis

地球上所有的生物都不断地暴露在各种环境压力下。生物体，如植物，没有移动和逃脱压力的能力，更经常受到不利影响。自然而然，植物就像大多数其他生物一样，发展出复杂的机制来感知和应对环境压力。分子伴侣是一组蛋白质，其中大部分在热休克条件下高度诱导，因此被称为热休克蛋白(HSP)，以帮助其他蛋白质在应激条件下正常发挥作用。分子伴侣在正常生长条件下维持其他蛋白质的正常活性也很重要，并在细胞蛋白质质量控制系统中发挥关键作用。我正在提出一个研究计划，研究模式植物拟南芥中一组特殊的分子伴侣，称为HSP90，并探索哪些其他蛋白质在拟南芥HSP90的帮助下，在正常和逆境条件下都能正常发挥作用。拟南芥含有7个HSP90基因。本研究将研究两个定位于叶绿体和内质网的拟南芥HSP90的生化特性，以及植物HSP90作为环境胁迫感受器的作用机制，并将通过蛋白质组学的方法确定可能用于未来育种更好地抵抗生物或非生物胁迫的作物的靶标。拟议的研究计划还将补充哺乳动物细胞中HSP90的研究，目前哺乳动物细胞中的这种蛋白质被用作癌症研究的靶点。

All living organisms on the earth are continuously exposed to a variety of environmental stresses. Organisms such as plants do not have the ability to move and escape from the stresses and are more frequently affected adversely. Naturally, plants like most other organisms develop complex mechanisms to sensor and cope with environmental stresses. Molecular chaperones are a group of proteins, most of which are highly induced by heat shock and therefore termed as heat shock proteins (HSP), to help other proteins to function properly under stress conditions. Molecular chaperones are also important in the maintenance of proper activities of other proteins under normal growth conditions and serve as critical players in the cellular protein quality control system. I am proposing a research program to study a particular set of molecular chaperones termed HSP90 in the model plant Arabidopsis and to explore what other proteins are aided by Arabidopsis HSP90 for their proper functions under both normal and stress conditions. Arabidopsis contains seven HSP90 genes. This study will investigate the biochemical properties of two Arabidopsis HSP90s which are localized in chloroplast and endoplasmic reticulum and the mechanism of action of plant HSP90s as sensors of environmental stresses, and will identify, by proteomics approaches, targets which can be potentially used for future breeding of crops with better resistance to biotic or abiotic stresses. The proposed research program will also complement the research on HSP90 in mammalian cells, where this protein is currently used as a target for cancer research.