Mammalian MagT1 and TUSC3 are required for cellular magnesium uptake and vertebrate embryonic development
- Proc Natl Acad Sci U S A. 2009 Sep 15;106(37):15750-5. doi: 10.1073/pnas.0908332106.
- 1. Department of Cardiology, Howard Hughes Medical Institute, Manton Center for Orphan Disease, Children's Hospital Boston, and Harvard Medical School, 1309 Enders, 320 Longwood Avenue, Boston, MA 02115, USA.
Magnesium (Mg(2+)) is the second most abundant cation in cells, yet relatively few mechanisms have been identified that regulate cellular levels of this ion. The most clearly identified Mg(2+) transporters are in bacteria and yeast. Here, we use a yeast complementary screen to identify two mammalian genes, MagT1 and TUSC3, as major mechanisms of Mg(2+) influx. MagT1 is universally expressed in all human tissues and its expression level is up-regulated in low extracellular Mg(2+). Knockdown of either MagT1 or TUSC3 protein significantly lowers the total and free intracellular Mg(2+) concentrations in mammalian cell lines. Morpholino knockdown of MagT1 and TUSC3 protein expression in zebrafish embryos results in early developmental arrest; excess Mg(2+) or supplementation with mammalian mRNAs can rescue the effects. We conclude that MagT1 and TUSC3 are indispensable members of the vertebrate plasma membrane Mg(2+) transport system.