title: Rice DEP1, encoding a highly cysteine-rich G protein γ subunit, confers cadmium tolerance on yeast cells and plants.
abstract: A rice cDNA, OsDEP1, encoding a highly cysteine (Cys)-rich G protein γ subunit, was initially identified as it conferred cadmium (Cd) tolerance on yeast cells. Of the 426 aa constituting OsDEP1, 120 are Cys residues (28.2%), of which 88 are clustered in the C-terminal half region (aa 170-426). To evaluate the independent effects of these two regions, two truncated versions of the OsDEP1-expressing plasmids pOsDEP1(1-169) and pOsDEP1(170-426) were used to examine their effects on yeast Cd tolerance. Although OsDEP1(170-426) conferred a similar level of Cd tolerance as the intact OsDEP1, OsDEP1(1-169) provided no such tolerance, indicating that the tolerance effect is localized to the aa 170-426 C-terminal peptide region. The Cd responses of transgenic Arabidopsis plants constitutively expressing OsDEP1, OsDEP1(1-169) or OsDEP1(170-426), were similar to the observations in yeast cells, with OsDEP1 and OsDEP1(170-426) transgenic plants displaying Cd tolerance but OsDEP1(1-169) plants showing no such tolerance. In addition, a positive correlation between the transcript levels of OsDEP1 or OsDEP1(170-426) in the transgenics and the Cd content of these plants upon Cd application was observed. As several Arabidopsis loss-of-function heterotrimeric G protein β and γ subunit gene mutants did not show differences in their Cd sensitivity compared with wild-type plants, we propose that the Cys-rich region of OsDEP1 may function directly as a trap for Cd ions.
authors.affiliation: Graduate School of Life Sciences, Tohoku University, 2-1-1 Katahira, Aoba, Sendai, Miyagi 980-8577, Japan.
authors.forename: Shuta
authors.initials: S
authors.lastname: Kunihiro
authors.forename: Tatsuhiko
authors.initials: T
authors.lastname: Saito
authors.forename: Taiki
authors.initials: T
authors.lastname: Matsuda
authors.forename: Masataka
authors.initials: M
authors.lastname: Inoue
authors.forename: Masato
authors.initials: M
authors.lastname: Kuramata
authors.forename: Fumio
authors.initials: F
authors.lastname: Taguchi-Shiobara
authors.forename: Shohab
authors.initials: S
authors.lastname: Youssefian
authors.forename: Thomas
authors.initials: T
authors.lastname: Berberich
authors.forename: Tomonobu
authors.initials: T
authors.lastname: Kusano
mesh_terms: D000222:Adaptation, Physiological / Q000187:drug effects*; D017360:Arabidopsis / Q000187:drug effects / Q000235:genetics; D002104:Cadmium / Q000633:toxicity*; D003300:Copper / Q000633:toxicity; D003545:Cysteine / Q000378:metabolism*; D044388:GTP-Binding Protein gamma Subunits / Q000737:chemistry / Q000378:metabolism*; D009154:Mutation / Q000235:genetics; D012275:Oryza / Q000187:drug effects / Q000378:metabolism* / Q000502:physiology; D010940:Plant Proteins / Q000737:chemistry / Q000378:metabolism*; D030821:Plants, Genetically Modified; D017434:Protein Structure, Tertiary; D015203:Reproducibility of Results; D012441:Saccharomyces cerevisiae / Q000166:cytology / Q000187:drug effects / Q000502:physiology*
chemical_list: D044388:GTP-Binding Protein gamma Subunits; D010940:Plant Proteins; D002104:Cadmium; D003300:Copper; D003545:Cysteine
keywords: G protein γ subunit; Oryza sativa; OsDEP1.; cadmium tolerance; cysteine-rich protein; heterotrimeric G protein signalling