RT Journal Article SR Electronic T1 AtHMA3, a P1B-ATPase Allowing Cd/Zn/Co/Pb Vacuolar Storage in Arabidopsis JF Plant Physiology JO Plant Physiol. FD American Society of Plant Biologists SP 894 OP 904 DO 10.1104/pp.108.130294 VO 149 IS 2 A1 Morel, Mélanie A1 Crouzet, Jérôme A1 Gravot, Antoine A1 Auroy, Pascaline A1 Leonhardt, Nathalie A1 Vavasseur, Alain A1 Richaud, Pierre YR 2009 UL http://www.plantphysiol.org/content/149/2/894.abstract AB The Arabidopsis (Arabidopsis thaliana) Heavy Metal Associated3 (AtHMA3) protein belongs to the P1B-2 subgroup of the P-type ATPase family, which is involved in heavy metal transport. In a previous study, we have shown, using heterologous expression in the yeast Saccharomyces cerevisiae, that in the presence of toxic metals, AtHMA3 was able to phenotypically complement the cadmium/lead (Cd/Pb)-hypersensitive strain ycf1 but not the zinc (Zn)-hypersensitive strain zrc1. In this study, we demonstrate that AtHMA3 in planta is located in the vacuolar membrane, with a high expression level in guard cells, hydathodes, vascular tissues, and the root apex. Confocal imaging in the presence of the Zn/Cd fluorescent probe BTC-5N revealed that AtHMA3 participates in the vacuolar storage of Cd. A T-DNA insertional mutant was found more sensitive to Zn and Cd. Conversely, ectopic overexpression of AtHMA3 improved plant tolerance to Cd, cobalt, Pb, and Zn; Cd accumulation increased by about 2- to 3-fold in plants overexpressing AtHMA3 compared with wild-type plants. Thus, AtHMA3 likely plays a role in the detoxification of biological (Zn) and nonbiological (Cd, cobalt, and Pb) heavy metals by participating in their vacuolar sequestration, an original function for a P1B-2 ATPase in a multicellular eukaryote.