Probably involved in redistribution of internalized aluminum. May mediate vacuolar sequestration of a metal complex. Expressed in the vascular tissue of roots, leaves, stems and flowers, in the distal portion of the root tip, in leaf hyathodes and in anther filaments, pistils and flower receptacles. Not induces by aluminum treatment. Belongs to the ABC transporter superfamily. ABCB family. Multidrug resistance exporter (TC 3.A.1.201) subfamily.