Abstract
The human solute carrier, SLC41Al, is a $Mg^{2}+$ transporter that is regulated by extracellular magnesium. Although intracellular magnesium plays a fundamental role in cellular metabolism, little is known about how $Mg^{2}+$ is taken up and controlled by cells. Magnesium plays a fundamental role in cellular metabolism so that its control within the body is critical. Magnesium homeostasis is principally a balance between intestinal absorption of dietary magnesium and renal excretion of urinary magnesium. The kidney, mainly the distal convoluted tubule, controls magnesium reabsorption. Although renal reabsorption is under the influence of many hormones, selective regulation of magnesium transport is due to intrinsic control involving transcriptional processes and synthesis of transport proteins. Using microarray analysis, identification of the genetic elements involved with this transcriptional control has been begun. SLC41A1(GenBank Accession No. AJ514402), comprises 10 putative transmembrane domains, two of which are highly homologous to the integral membrane part of the prokaryote transports $Mg^{2}+$ and other divalent cations $Sr^2+,\;Zn^2+,\;Cu^2+,\;Fe^2+,\;Co^2+,\;Ba^2+,\;and\;Cd^2+,\;but\;not\;Ca^2+,\;Mn^2+,\;and\;Ni^2+.$ Transport of $Mg^{2}+$ by SLC41Al is rheogenic, voltage dependent, and not coupled to Na or Cl. Expressed SLC41Al transports a range of other divalent cations: $Mg^{2+},\;Sr^{2+},\;Zn^{2+},\;Cu^{2+},\;Fe^{2+},\;Co^{2+},\;Ba^{2+},\;and\;Cd^{2+}$. The divalent cations $Ca^{2+},\;Mn^{2+},\;and\;Ni^{2+}$and the trivalent ion $Gd^{3+}$ did not induce currents nor did they inhibit $Mg^{2+}$ transport. The nonselective cation $La^{3+}$ abolishes $Mg^{2+}$ uptake. Computer analysis of the SLC41Al protein structure reveals that it belongs to MgtE protein family & suggested that the human solute carrier, SLC41Al, might be a eukaryotic $Mg^{2+}$ transporter closely related $(60-70\%)$ protein encoded by SLC41A2 is a $Mg^{2}+$ transporter that might be involved in magnesium homeostasis in epithelial cells also transports a range of other divalent cations: $Ba^2,\;Ni^2,\;CO^2,\;Fe^2,\;or\;Mn^2,\;but\;not\;Ca^2,\;Zn^2,\;or\;Cu^{2+}$ that may have related functional properties.