The Mg 2+ transporter MagT1 partially rescues cell growth and Mg 2+ uptake in cells lacking the channel‐kinase TRPM7

Magnesium (Mg 2+ ) transport across membranes plays an essential role in cellular growth and survival. TRPM7 is the unique fusion of a Mg 2+ permeable pore with an active cytosolic kinase domain, and is considered a master regulator of cellular Mg 2+ homeostasis. We previously found that the genetic deletion of TRPM7 in DT40 B cells results in Mg 2+ deficiency and severe growth impairment, which can be rescued by supplementation with excess extracellular Mg 2+ . Here, we show that gene expression of the Mg 2+ selective transporter MagT1 is upregulated in TRPM7 −/− cells. Furthermore, overexpression of MagT1 in TRPM7 −/− cells augments their capacity to uptake Mg 2+ , and improves their growth behavior in the absence of excess Mg 2+ .