Department of Plant Medicine, Institute of Agriculture and Life Science, Gyeongsang National University, Jinju, 52828, Republic of Korea.
Grassland & Forages Division, National Institute of Animal Science, Rural Development Administration, Cheonan, 31000, Republic of Korea.
Biochem Biophys Res Commun. 2022 Jan 1;586:171-176. doi: 10.1016/j.bbrc.2021.11.080. Epub 2021 Nov 24.
High temperature stress is an environmental factor that negatively affects the growth and development of crops. Hsp90 (90 kDa heat shock protein) is a major molecular chaperone in eukaryotic cells, contributing to the maintenance of cell homeostasis through interaction with co-chaperones. Aha1 (activator of Hsp90 ATPase) is well known as a co-chaperone that activates ATPase activity of Hsp90 in mammals. However, biochemical and physiological evidence relating to Aha has not yet been identified in plants. In this study, we investigated the heat-tolerance function of orchardgrass (Dactylis glomerata L.) Aha (DgAha). Recombinant DgAha interacted with cytosolic DgHsp90s and efficiently protected substrates from thermal denaturation. Furthermore, heterologous expression of DgAha in yeast (Saccharomyces cerevisiae) cells and Arabidopsis (Arabidopsis thaliana) plants conferred thermotolerance in vivo. Enhanced expression of DgAha in Arabidopsis stimulates the transcription of Hsp90 under heat stress. Our data demonstrate that plant Aha plays a positive role in heat stress tolerance via chaperone properties and/or activation of Hsp90 to protect substrate proteins in plants from thermal injury.
高温胁迫是一种影响作物生长和发育的环境因素。Hsp90（90 kDa 热休克蛋白）是真核细胞中的主要分子伴侣，通过与共伴侣相互作用有助于维持细胞内稳态。Aha1（Hsp90 ATP 酶激活因子）是一种众所周知的共伴侣，在哺乳动物中激活 Hsp90 的 ATP 酶活性。然而，与植物中的 Aha 相关的生化和生理证据尚未被确定。在这项研究中，我们研究了果园草（Dactylis glomerata L.）Aha（DgAha）的耐热功能。重组 DgAha 与细胞质 DgHsp90s 相互作用，并有效地防止底物受热变性。此外，DgAha 在酵母（Saccharomyces cerevisiae）细胞和拟南芥（Arabidopsis thaliana）植物中的异源表达赋予了体内的耐热性。在拟南芥中增强 DgAha 的表达可刺激 Hsp90 在热应激下的转录。我们的数据表明，植物 Aha 通过伴侣特性和/或激活 Hsp90 发挥积极作用，以保护植物中的底物蛋白免受热损伤，从而提高植物对热应激的耐受性。
