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

地球上的所有生物都不断受到各种环境压力的影响。像植物这样的生物没有移动和逃避压力的能力，因此更频繁地受到不利影响。自然地，植物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。分子伴侣蛋白（Molecular chaperones，简称HSP）是一组蛋白质，大多数是由热休克高度诱导的，因此被称为热休克蛋白（heat shock proteins， HSP），帮助其他蛋白质在应激条件下正常工作。在正常生长条件下，分子伴侣在维持其他蛋白质的正常活性方面也很重要，并且在细胞蛋白质质量控制系统中起着关键作用。我正在提出一个研究项目，研究模式植物拟南芥中一组被称为HSP90的分子伴侣，并探索在正常和逆境条件下，拟南芥HSP90辅助了哪些其他蛋白质的正常功能。拟南芥含有7个HSP90基因。本研究将对拟南芥叶绿体和内质网中两种hsp90的生化特性和作为环境胁迫传感器的植物hsp90的作用机制进行研究，并通过蛋白质组学的方法，为今后选育抗生物或非生物胁迫的作物提供潜在的靶点。拟议的研究项目还将补充哺乳动物细胞中热休克蛋白90的研究，目前这种蛋白被用作癌症研究的靶标。

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.