Methallothionein (MT) is a low molecular weight cysteine rich metalloprotein. In mammals, there are four isoforms
(MT-1, -2, -3, and -4) and they have multiple roles, such as the detoxification of heavy metals, regulating essential
metal homeostasis, and protecting against oxidative stress. Recently, accumulating studies have suggested that MTs (especially
MT-1, -2, and -3) are an important neuroprotective substance for cerebral ischemia and retinal diseases, such as
age-related macular degeneration (AMD) and retinitis pigmentosa (RP), that are characterized by a progressive retinal degeneration.
Oxidative stress and/or zinc toxicity has been implicated as part of the common pathway in these diseases.
Studying the expression patterns and functions of MTs may broaden our understanding of the endogenous molecular responses
that these diseases trigger, and may help us to develop new therapeutic strategies to treat them. However, the precise
roles of MTs within the brain and retina are not fully understood in terms of neuropathological conditions. In this review,
we discuss the recent findings focusing on MTs’ functions following cerebral ischemia, AMD, and RP.