Magnesium transporters are proteins that transport magnesium across the cell membrane. All forms of life require magnesium, yet the molecular mechanisms of Mg uptake from the environment and the distribution of this vital element within the organism are only slowly being elucidated.
The ATPase function of MgtA is highly cardiolipin dependent and has been shown to detect free magnesium in the μM range 
In bacteria, Mg is probably mainly supplied by the CorA protein and, where the CorA protein is absent, by the MgtE protein. In yeast the initial uptake is via the Alr1p and Alr2p proteins, but at this stage the only internal Mg distributing protein identified is Mrs2p. Within the protozoa only one Mg transporter (XntAp) has been identified. In metazoa, Mrs2p and MgtE homologues have been identified, along with two novel Mg transport systems TRPM6/TRPM7 and PCLN-1. Finally, in plants, a family of Mrs2p homologues has been identified along with another novel protein, AtMHX.