Transthyretin (TTR), an amyloid-beta (Ab) scavenger protein, and metallo-thioneins 2 and 3 (MT2 and MT3), low molecular weight metal-binding proteins, have recognized impacts in Abmetabolism. Because TTR binds MT2, an ubiquitous isoform of the MTs, we investigated whether it also interacts with MT3, an isoform of the MTs predominantly expressed in the brain, and studied the role of MT2 and MT3 in human TTR–Abbinding.