Neuroprotective and neuroregenerative properties of metallothioneins.

Metallothioneins (MTs) are low-molecular weight cysteine- and metal-rich proteins with unquestionable metal binding capacity, antioxidant and anti-inflammatory properties, and a clear involvement in diverse physiological actions as inhibition of proapoptotic mechanisms, enhancement of cell survival, and tissue regeneration. Concurrent with this wide array of functions, MT-1/2 have been implicated in neuroprotection and neuroregeneration. The zinc binding capacity and antioxidant properties of MTs may account for most of their physiological features in the brain. However, some receptor-mediated actions of MT-1/2 have also been reported recently, a subject to be fully elucidated. This review analyses and updates the current knowledge on the actions of MTs related to neuroprotection and neuroregeneration in an effort to distinguish receptor-mediated actions of MTs from those arising from its zinc binding capacity and its antioxidant properties.