The function of metallothionein.

Since its discovery in 1957 metallothionein (MT) has remained a protein in search of a function. After 40 years of frustrating efforts, three areas of research point to its zinc cluster structure as the basis of its functional potential: (1) the regulation of MT gene expression by zinc-dependent transcription factors, (2) neuronal growth inhibition in brain, and (3) interactions with glutathione and zinc proteins.