Functional characterization of orchardgrass endoplasmic reticulum-resident Hsp90 (DgHsp90) as a chaperone and an ATPase

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• 作者：Joon-Yung Cha ; Min Hee Jung ; Netty Ermawati ; Mukhamad Su'udi ; Gyu-Jin Rho ; Chang-deok Han ; Kon Ho Lee ; Daeyoung Son
• 关键词：ATPase ; Chaperone ; Endoplasmic reticulum ; Heat shock protein 90 ; Orchardgrass (Dactylis glomerata L.) ; Thermotolerance
• 刊名：Plant Physiology and Biochemistry
• 出版年：2009
• 出版时间：October 2009
• 年：2009
• 卷：47
• 期：10
• 页码：859-866
• 全文大小：1294 K

文摘

Hsp90 proteins are essential molecular chaperones regulating multiple cellular processes in distinct subcellular organelles. In this study, we report the functional characterization of a cDNA encoding endoplasmic reticulum (ER)-resident Hsp90 from orchardgrass (DgHsp90). DgHsp90 is a 2742 bp cDNA with an open reading frame predicted to encode an 808 amino acid protein. DgHsp90 has a well conserved N-terminal ATPase domain and a C-terminal Hsp90 domain and ER-retention motif. Expression of DgHsp90 increased during heat stress at 35 °C or H₂O₂ treatment. DgHsp90 also functions as a chaperone protein by preventing thermal aggregation of malate dehydrogenase (EC 1.1.1.37) and citrate synthase (EC 2.3.3.1). The intrinsic ATPase activity of DgHsp90 was inhibited by geldanamycin, an Hsp90 inhibitor, and the inhibition reduced the chaperone activity of DgHsp90. Yeast cells overexpressing DgHsp90 exhibited enhanced thermotolerance.