Putative component of the machinery responsible for pumping aminotriazole (and possibly other toxic compounds) out of the cell. Probable ATP-dependent export permease. Appears to confer resistance only to aminotriazole. Deletion of the C-terminal 34 residues abolishes ATR1 activity, while deletion of the C-terminal 23 residues have a minor effect. Present with 1720 molecules/cell in log phase SD medium. Belongs to the major facilitator superfamily.