MT1A

MT1A, or metallothionein-1A, is a small, cysteine-rich protein encoded by the MT1A gene in humans. It is part of the metallothionein family, a group of proteins that bind divalent metal ions and play a role in metal homeostasis and detoxification.

The MT1A protein binds metals such as zinc, cadmium, copper, and mercury. Its metal-binding properties contribute to intracellular metal ion regulation, detoxification of heavy metals, and protection against oxidative stress. Metallothioneins may also influence cell proliferation and apoptosis under conditions of metal exposure.

MT1A expression is inducible by metal exposure, especially zinc and cadmium, and by glucocorticoids. Regulation occurs in part through metal-responsive transcription factor 1 (MTF-1), which binds to metal response elements in MT gene promoters. Basal expression of MT1A occurs in several tissues, with relatively high levels in the liver and kidney.

Genomic organization places MT1A within a cluster of MT1 family genes on chromosome 16q13 in humans, alongside MT1B, MT1E, MT1F, MT1G, and MT1H. The metallothionein proteins are highly conserved across vertebrates, reflecting their fundamental role in metal handling and detoxification.

Clinical and research relevance centers on MT1A’s response to metal exposure and its altered expression in various disease contexts. MT1A levels are used as biomarkers of metal exposure and oxidative stress in some studies. Genetic variation in MT1A or its regulatory elements may influence individual metal tolerance, though the clinical significance of specific variants requires further study. See also metallothionein, metal-regulatory transcription factor 1, and metal exposure biomarkers.