Metal transporter involved in the sequestration of aluminum into vacuoles, which is required for cellular detoxification of aluminum. Expressed in primary roots ans lateral roots. Induced by aluminum in roots. No visible phenotype under normal growth conditions, but mutant plants are hypersensitive to aluminum. Belongs to the ABC transporter superfamily. ABCB family. Multidrug resistance exporter (TC 3.A.1.201) subfamily.