AtHMA3, a P1B-ATPase Allowing Cd/Zn/Co/Pb Vacuolar Storage in Arabidopsis 

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…