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The plant CDF family member TgMTP1 from the Ni/Zn hyperaccumulator Thlaspi goesingense acts to enhance efflux of Zn at the plasma membrane when expressed in Saccharomyces cerevisiae

Kim, Dong-giun (Center for Plant Environmental Stress Physiology, Purdue University) , Jeffery L Gustin (Center for Plant Environmental Stress Physiology, Purdue University) , Brett Lahner (Center for Plant Environmental Stress Physiology, Purdue University) , Michael W. Persans (Center for Plant Environmental Stress Physiology, Purdue University) , Baek, Dong-won (Division of Applied Life Science (BK21 Program) and Environmental Biotechnology National Core Research Center, Graduate School of Gyeongsang National University) , Yun, Dae-Jin (Division of Applied Life Science (BK21 Program) and Environmental Biotechnology National Core Research Center, Graduate School of Gyeongsang National University) , David E. Salt (Center for Plant Environmental Stress Physiology, Purdue University)

Plant molecular biology and biotechnology research center Annual report, 2004, 2004, 173-187

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To avoid metal toxicity, organisms have evolved mechanisms including efflux of metal ions from cells and sequestration into internal cellular compartments. Members of the ubiquitous cation diffusion facilitator (CDF) family are known to play an important role in these processes. Overexpression of th...
To avoid metal toxicity, organisms have evolved mechanisms including efflux of metal ions from cells and sequestration into internal cellular compartments. Members of the ubiquitous cation diffusion facilitator (CDF) family are known to play an important role in these processes. Overexpression of the plant CDF family member metal tolerance protein 1 (MTP1) from the Ni/Zn hyperaccumulator Thlaspi goesingense (TgMTP1), in the Saccharomyces cerevisiae Δ zinc resistance conferring (zrc)1Δ cobalt transporter (cot)1 double mutant, suppressed the Zn sensitivity of this strain. T. goesingense was found to contain several allelic variants of TgMTP1, all of which confer similar resistance to Zn in Δzrc1Δcot1. similarly, MTP1 from various hyperaccumulator and non-accumulator species also confer similar resistance to Zn. Δzrc1Δcot1 lacks the ability to accumulate Zn in the vacuole and has lower accumulation of Zn after either long- or short-term Zn exposure. Expression of TgMTP1 in Δzrc1Δcot1 leads to further lowering of Zn accumulation and an increase in Zn efflux from the cells. Expression of TgMTP1 in a V-type ATPase-deficient S. cerevisiae strain also confers increased Zn resistance. in vivo and in vitro immunological staining of hemagglutinin (HA)-tagged TgMTP1::HA reveals the protein to be localized in both the S. cerevisiae vacuolar and plasma membrane Zn efflux, acting to confer Zn resistance independent of the vacuole in S. cerevisiae. Transient expression in Arabidopsis thaliana protoplasts also reveals that TgMTP1::green fluorescent protein (GFP) is localized at the plasma membrane, suggesting that TgMTP1 may also enhance Zn efflux in plants.