MT3 and Alzheimer disease: The protective role of MT-3 from AD pathology has been implicated based on the finding that the protein (a) is down-regulated in AD, (b) shows extracellular growth inhibitory activity and antagonizes the ability of AD brain extract to stimulate survival and neuritic sprouting, and (c) protects, by an unknown mechanism, the neuronal cells from the toxic effect of amyloid peptide Aβ1–40 [4,5,10,11,39].