Related Experiment Video
Updated: Jul 18, 2026

Functional Characterization of Endogenously Expressed Human RYR1 Variants
Published on: June 9, 2021
Mechanisms, regulation and pathologic significance of Mg2+ efflux from erythrocytes
1Charité-Universitätsmedizin Berlin, Campus Benjamin Franklin, Institut für Molekularbiologie und Biochemie, Arnimallee 22, 14195 Berlin, Germany.
Abstract:
Mg2+ efflux from erythrocytes can be performed by the Na+/Mg2+ antiport and by Na+-independent Mg2+ efflux. Na+-independent Mg2+ efflux functions via the unspecific choline exchanger as choline/Mg2+ or K+/Mg2+ antiport and as Mg2+ efflux accompanied by intracellular Cl- for charge compensation, as found for example in sucrose medium. Na+/Mg2+ antiport in erythrocytes exchanges 2 extracellular Na+ for 1 intracellular Mg2+. Driving forces are the Na+ and Mg2+ gradients. By reversing these gradients, the Na+/Mg2+ antiporter can mediate Mg2+ influx. The Na+/Mg2+ antiporter can exchange 24Mg2+ for 28Mg2+ and other divalent cations for intracellular Mg2+. In the exchange mechanism, extra- and intracellular Na+ can compete with Mg2+. Na+/Mg2+ antiport is inhibited by amiloride, quinidine and imipramine. Na+/Mg2+ antiport is drastically activated by intracellular Mg2+ due to an allosteric transition. The affinity of intracellular Mg2+ to the Na+/Mg2+ antiporter is dependent on intracellular ATP due to phosphorylation. Besides this mechanism, in non Mg2+-loaded erythrocytes, the activity of Na+/Mg2+ antiport is regulated by phosphorylation-dephosphorylation and by intracellular Cl-. The drastically Mg2+-activated Na+/Mg2+ antiporter is not further stimulated by phosphorylation and intracellular Cl-. Na+-independent Mg2+ efflux via the choline exchanger is also inhibited by amiloride, quinidine and imipramine, and can also be regulated by phosphorylation-dephosphorylation. Na+/Mg2+ antiport of erythrocytes is altered in various pathologic conditions.
Related Concept Videos
Disorders of Erythrocytes
Erythrocyte disorders can be broadly categorized into two main types: anemic and polycythemic conditions.
A low oxygen-carrying capacity of the blood due to the loss, lower production, or destruction of erythrocytes is termed anemia. Hemorrhagic anemia, for example, occurs when bleeding from an external wound or internal ulcer reduces erythrocyte counts.
On the other...
Erythropoiesis
Factors Affecting Erythropoiesis
Several factors influence the erythrocyte production rate, with tissue oxygen level being among the most critical. Intense exercise or high altitudes can cause tissue hypoxia, which triggers the kidneys to release more erythropoietin (EPO) into the bloodstream.
EPO then...
The Significance of Membrane Transport
Transporters facilitate either an active or passive movement of solutes. They can allow a single-molecule transport down its...
Regulation of Metabolism
Lifecycle of Erythrocytes
The resident phagocytic macrophages deal with these damaged cells by engulfing them and separating their globin and heme groups.

