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AtHMA1 contributes to the detoxification of excess Zn(II) in Arabidopsis
Author(s) -
Kim YuYoung,
Choi Hyunju,
Segami Shoji,
Cho HyungTaeg,
Martinoia Enrico,
Maeshima Masayoshi,
Lee Youngsook
Publication year - 2009
Publication title -
the plant journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.058
H-Index - 269
eISSN - 1365-313X
pISSN - 0960-7412
DOI - 10.1111/j.1365-313x.2009.03818.x
Subject(s) - detoxification (alternative medicine) , arabidopsis , chemistry , biology , medicine , gene , biochemistry , alternative medicine , pathology , mutant
Summary AtHMA1 is a member of the heavy metal‐transporting ATPase family. It exhibits amino acid sequence similarity to two other Zn(II) transporters, AtHMA2 and AtHMA4, and contains poly‐His motifs that are commonly found in Zn(II)‐binding proteins, but lacks some amino acids that are typical for this class of transporters. AtHMA1 localizes to the chloroplast envelope. In comparison with wild‐type plants, we observed a more pronounced sensitivity in the presence of high Zn(II) concentrations, and increased accumulation of Zn in the chloroplast of T‐DNA insertional mutants in AtHMA1 . The Zn(II)‐sensitive phenotype of AtHMA1 knock‐out plants was complemented by the expression of AtHMA1 under the control of its own promoter. The Zn(II)‐transporting activity of AtHMA1 was confirmed in a heterologous expression system, Saccharomyces cerevisiae . The sensitivity of yeast to high concentrations of Zn(II) was altered by the expression of AtHMA1 lacking its N‐terminal chloroplast‐targeting signal. Taken together, these results suggest that under conditions of excess Zn(II), AtHMA1 contributes to Zn(II) detoxification by reducing the Zn content of Arabidopsis thaliana plastids.