Modulation of Na+/Mg2+ exchanger stoichiometry ratio by Cl− ions in basolateral rat liver plasma membrane vesicles

Cefaratti, Christie; Romani, Andrea

doi:10.1007/s11010-011-0720-x

Cited by 5 publications

(7 citation statements)

References 31 publications

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“…cell isolation vs. cultured cells), composition of the incubation medium, or modality of cell Mg 2+ loading. In keeping with these possibilities, a recent report of ours suggests that the extrusion of Mg 2+ via the Na + /Mg 2+ exchanger is coupled to the outward movement of Cl − ions [138]. Under conditions in which Cl− is not present, the electrogenic exchange 1Na + in :1Mg 2+ out becomes electroneutral (2Na + in :1Mg 2+ out ) [138].…”

Section: Mg2+ Transport Mechanismsmentioning

confidence: 82%

“…In keeping with these possibilities, a recent report of ours suggests that the extrusion of Mg 2+ via the Na + /Mg 2+ exchanger is coupled to the outward movement of Cl − ions [138]. Under conditions in which Cl− is not present, the electrogenic exchange 1Na + in :1Mg 2+ out becomes electroneutral (2Na + in :1Mg 2+ out ) [138]. Interestingly, only inhibitors of the Na + /Mg 2+ exchanger block Cl − extrusion in addition to inhibiting Mg 2+ mobilization whereas more or less specific inhibitors of Cl − transporters (e.g.…”

Section: Mg2+ Transport Mechanismsmentioning

confidence: 83%

“…Upon removal of intravesicular Cl−, the stoichiometry ratio of the exchanger switches from electrogenic to electroneutral (i.e. 2Na + in :1Mg 2+ out ) [138]. Interestingly, in the presence of intra-vesicular Cl − , an extrusion of ~35nmol Cl − /mg protein is observed within 1min from the addition of external Na + , in concomitance with the extrusion of Mg 2+ and the accumulation of external Na + into the vesicles [138].…”

Section: Mg2+ Transport Mechanismsmentioning

confidence: 99%

“…2Na + in :1Mg 2+ out ) [138]. Interestingly, in the presence of intra-vesicular Cl − , an extrusion of ~35nmol Cl − /mg protein is observed within 1min from the addition of external Na + , in concomitance with the extrusion of Mg 2+ and the accumulation of external Na + into the vesicles [138]. The Cl − extrusion is not inhibited by inhibitors of anion transport (e.g.…”

Section: Mg2+ Transport Mechanismsmentioning

confidence: 99%

“…DNDS, DIDS, or niflumic acid), of the Na/K/Cl cotransporter NKCC1 (e.g. bumetanide or furosemide) [138], thus excluding that Clmovement occurs via one of these mechanisms. The only agent able to block Cl − extrusion is imipramine [138], which specifically blocks the operation of the Na + /Mg 2+ exchanger in the basolateral domain of the hepatocyte [175].…”

Section: Mg2+ Transport Mechanismsmentioning

confidence: 99%

See 4 more Smart Citations

Cellular magnesium homeostasis

Romani

2011

Archives of Biochemistry and Biophysics

441

425

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Magnesium, the second most abundant cellular cation after potassium, is essential to regulate numerous cellular functions and enzymes, including ion channels, metabolic cycles, and signaling pathways, as attested by more than 1000 entries in the literature. Despite significant recent progress, however, our understanding of how cells regulate Mg2+ homeostasis and transport still remains incomplete. For example, the occurrence of major fluxes of Mg2+ in either direction across the plasma membrane of mammalian cells following metabolic or hormonal stimuli has been extensively documented. Yet, the mechanisms ultimately responsible for magnesium extrusion across the cell membrane have not been cloned. Even less is known about the regulation in cellular organelles. The present review is aimed at providing the reader with a comprehensive and up-to-date understanding of the mechanisms enacted by eukaryotic cells to regulate cellular Mg2+ homeostasis and how these mechanisms are altered under specific pathological conditions.

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Section: Mg2+ Transport Mechanismsmentioning

confidence: 82%

Section: Mg2+ Transport Mechanismsmentioning

confidence: 83%

Section: Mg2+ Transport Mechanismsmentioning

confidence: 99%

Section: Mg2+ Transport Mechanismsmentioning

confidence: 99%

Section: Mg2+ Transport Mechanismsmentioning

confidence: 99%

See 3 more Smart Citations

Cellular magnesium homeostasis

Romani

2011

Archives of Biochemistry and Biophysics

441

425

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Interplay of Ca2+ and Mg2+ in Sodium-Calcium Exchanger and in Other Ca2+-Binding Proteins: Magnesium, Watchdog That Blocks Each Turn if Able

Levitsky

Takahashi

2012

Advances in Experimental Medicine and Biology

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Sodium-calcium exchange across plasma membrane is regulated by intracellular calcium ions. The sodium-calcium exchanger (NCX1) is activated by successive saturation of numerous Ca(2+)-binding sites located in the intracellular loop of the protein. The progressive saturation of the binding domain CBD12 by Ca(2+) results in a series of conformational changes of CBD12 as well as of entire NCX1 molecule. Like other soluble and membrane Ca(2+)-binding proteins, NCX1 can also be regulated by Mg(2+) that antagonises Ca(2+) at the level of divalent cation-binding sites. This chapter summarises data on Mg(2+) impacts in the cells. Regulatory action of Mg(2+) on intracellular Ca(2+)-dependent processes can be achieved due to changes of its cytoplasmic level, which take place in the range of [Mg(2+)](i) from 0.5 to 3 mM. Under normal conditions, these changes are ensured by activation of plasmalemmal Mg(2+) transport systems and by variations in ATP level in cytoplasm. In heart and in brain, some pathological conditions, such as hypoxia, ischemia and ischemia followed by reperfusion, are associated with an important increase in intracellular Ca(2+). The tissue damage due to Ca(2+) overload may be prevented by Mg(2+). The protective actions of Mg(2+) can be achieved due to its ability to compete with Ca(2+) for the binding sites in a number of proteins responsible for the rise in intracellular free Ca(2+), including NCX1, in case when the reverse mode of Na(+)/Ca(2+) exchange becomes predominant. Saturation of CBD12 by Mg(2+) results in important changes of NCX1 conformation. Modulating actions of Mg(2+) on the conformation of NCX1 were detected at a narrow range of Mg(2+) concentration, from 0.5 to 1 mM. These data support an idea that variations of intracellular Mg(2+) could modify transmembrane Ca(2+) movements ensured by NCX1.

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Magnesium Homeostasis in Mammalian Cells

Romani

2012

Metal Ions in Life Sciences

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Magnesium, the second most abundant cation within the cell, plays an important role in numerous biological functions. Experimental evidence indicates that mammalian cells tightly regulate cellular magnesium ion content through specific mechanisms controlling Mg(2+) entry and efflux across the cell membrane and the membrane of various cellular organelles as well as intracellular Mg(2+) buffering under resting conditions and following hormonal and metabolic stimuli. This chapter will provide an assessment of the various mechanisms controlling cellular Mg(2+) homeostasis and transport, and the implications changes in cellular Mg(2+) content play under physiological and pathological conditions.

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Modulation of Na+/Mg2+ exchanger stoichiometry ratio by Cl− ions in basolateral rat liver plasma membrane vesicles

Cited by 5 publications

References 31 publications

Cellular magnesium homeostasis

Cellular magnesium homeostasis

Interplay of Ca2+ and Mg2+ in Sodium-Calcium Exchanger and in Other Ca2+-Binding Proteins: Magnesium, Watchdog That Blocks Each Turn if Able

Magnesium Homeostasis in Mammalian Cells

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