title: Functional characterization of orchardgrass endoplasmic reticulum-resident Hsp90 (DgHsp90) as a chaperone and an ATPase.
abstract: 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 2742bp 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 degrees C or H(2)O(2) 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.
authors.affiliation: Division of Applied Life Science (BK21 Program), Gyeongsang National University, Jinju 660-701, Republic of Korea.
authors.forename: Joon-Yung
authors.initials: JY
authors.lastname: Cha
authors.forename: Min Hee
authors.initials: MH
authors.lastname: Jung
authors.forename: Netty
authors.initials: N
authors.lastname: Ermawati
authors.forename: Mukhamad
authors.initials: M
authors.lastname: Su'udi
authors.forename: Gyu-Jin
authors.initials: GJ
authors.lastname: Rho
authors.forename: Chang-Deok
authors.initials: CD
authors.lastname: Han
authors.forename: Kon Ho
authors.initials: KH
authors.lastname: Lee
authors.forename: Daeyoung
authors.initials: D
authors.lastname: Son
mesh_terms: D000222:Adaptation, Physiological; D000251:Adenosine Triphosphatases / Q000235:genetics / Q000378:metabolism*; D000595:Amino Acid Sequence; D001483:Base Sequence; D016227:Benzoquinones / Q000494:pharmacology; D015152:Blotting, Northern; D018076:DNA, Complementary / Q000737:chemistry / Q000235:genetics; D031745:Dactylis / Q000235:genetics / Q000378:metabolism*; D004721:Endoplasmic Reticulum / Q000378:metabolism*; D020869:Gene Expression Profiling; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D018841:HSP90 Heat-Shock Proteins / Q000145:classification / Q000235:genetics / Q000378:metabolism*; D006358:Hot Temperature; D006861:Hydrogen Peroxide / Q000494:pharmacology; D047029:Lactams, Macrocyclic / Q000494:pharmacology; D018832:Molecular Chaperones / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D016877:Oxidants / Q000494:pharmacology; D010802:Phylogeny; D010940:Plant Proteins / Q000145:classification / Q000235:genetics / Q000378:metabolism*; D017422:Sequence Analysis, DNA
chemical_list: D016227:Benzoquinones; D018076:DNA, Complementary; D018841:HSP90 Heat-Shock Proteins; D047029:Lactams, Macrocyclic; D018832:Molecular Chaperones; D016877:Oxidants; D010940:Plant Proteins; D006861:Hydrogen Peroxide; D000251:Adenosine Triphosphatases; C001277:geldanamycin