title: SLC41A1 is a novel mammalian Mg2+ carrier.
abstract: The molecular biology of mammalian magnesium transporters and their interrelations in cellular magnesium homeostasis are largely unknown. Recently, the mouse SLC41A1 protein was suggested to be a candidate magnesium transporter with channel-like properties when overexpressed in Xenopus laevis oocytes. Here, we demonstrate that human SLC41A1 overexpressed in HEK293 cells forms protein complexes and locates to the plasma membrane without, however, giving rise to any detectable magnesium currents during whole cell patch clamp experiments. Nevertheless, in a strain of Salmonella enterica exhibiting disruption of all three distinct magnesium transport systems (CorA, MgtA, and MgtB), overexpression of human SLC41A1 functionally substitutes these transporters and restores the growth of the mutant bacteria at magnesium concentrations otherwise non-permissive for growth. Thus, we have identified human SLC41A1 as being a bona fide magnesium transporter. Most importantly, overexpressed SLC41A1 provide HEK293 cells with an increased magnesium efflux capacity. With outwardly directed Mg(2+) gradients, a SLC41A1-dependent reduction of the free intracellular magnesium concentration accompanied by a significant net decrease of the total cellular magnesium concentration could be observed in such cells. SLC41A1 activity is temperature-sensitive but not sensitive to the only known magnesium channel blocker, cobalt(III) hexaammine. Taken together, these data functionally identify SLC41A1 as a mammalian carrier mediating magnesium efflux.
authors: Institute of Veterinary-Physiology, FU Berlin, Oertzenweg 19b, D-14163 Berlin, Germany. martink@zedat.fu-berlin.de
authors: Martin
authors: M
authors: Kolisek
authors: Pierre
authors: P
authors: Launay
authors: Andreas
authors: A
authors: Beck
authors: Gerhard
authors: G
authors: Sponder
authors: Nicolas
authors: N
authors: Serafini
authors: Marcel
authors: M
authors: Brenkus
authors: Elisabeth Maria
authors: EM
authors: Froschauer
authors: Holger
authors: H
authors: Martens
authors: Andrea
authors: A
authors: Fleig
authors: Monika
authors: M
authors: Schweigel
mesh_terms: D000818:Animals; D000970:Antineoplastic Agents / Q000494:pharmacology; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D027682:Cation Transport Proteins / Q000235:genetics / Q000378:metabolism*; D002460:Cell Line; D003035:Cobalt / Q000494:pharmacology; D005816:Genetic Complementation Test; D006801:Humans; D017136:Ion Transport / Q000502:physiology; D008274:Magnesium / Q000378:metabolism*; D051379:Mice; D019779:Salmonella enterica / Q000235:genetics / Q000378:metabolism; D014982:Xenopus laevis / Q000235:genetics / Q000378:metabolism
chemical_list: D000970:Antineoplastic Agents; D001426:Bacterial Proteins; D027682:Cation Transport Proteins; C476304:SLC41A1 protein, human; C501065:Slc41a2 protein, mouse; C032300:hexaamminecobalt(II); D003035:Cobalt; D008274:Magnesium