Effect of epidermal growth factor on magnesium homeostasis in BC3H1 myocytes

Grubbs, Robert D.

doi:10.1152/ajpcell.1991.260.6.c1158

Cited by 38 publications

(29 citation statements)

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“…It suggests that thymidine kinase is saturated for MgATP 2Ϫ , even in quiescent cells, whereas uridine kinase is not saturated in such cells and could be activated by any increase in Mg 2ϩ induced by growth factors. That Mg 2ϩ , rather than ATP 4Ϫ , is the regulator of uridine trapping is consistent with the failure of ATP to increase in growth-stimulated cells (17,(20)(21)(22), whereas total Mg 2ϩ (23,24) and free Mg 2ϩ (25,26) do increase in a sustained manner after treatment with growth factors.There are, however, some problems in a simple interpretation of the published effects on uridine uptake͞trapping caused by varying the Mg 2ϩ concentration in cells. To achieve a wide range of Mg 2ϩ concentrations in cells, the Ca 2ϩ concentration of the medium was reduced to increase the permeability of the cells to Mg 2ϩ (16,17,27).…”

supporting

confidence: 58%

supporting

confidence: 58%

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Mg ²⁺ as activator of uridine phosphorylation in coordination with other cellular responses to growth factors

Vidair

Rubin

2005

Proc. Natl. Acad. Sci. U.S.A.

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The divalent cation ionophore A23187 facilitates the manipulation of intracellular Mg 2؉ without increasing the general permeability of the cell. The uptake of uridine into cells is limited by its rate of intracellular phosphorylation that increases within minutes after the addition of growth factors. In the experiments described here, the rate of uridine uptake in ionophore-treated cells stimulated by either serum or insulin depended on the extracellular and intracellular concentrations of Mg 2؉ and was independent of the extracellular Ca 2؉ concentration. In very high concentrations of Mg 2؉ (50 mM), ionophore-treated cells take up uridine as fast, in the absence of growth factors as in their presence, demonstrating that Mg 2؉ can replace the growth factor requirement for the stimulation of uridine uptake. In contrast, thymidine uptake, which also is limited by its rate of intracellular phosphorylation, showed no early response to either growth factors or Mg 2؉ concentration, which is consistent with the 10-fold lower Mg 2؉ requirement of thymidine kinase compared with uridine kinase. The feedback inhibition of uridine kinase by UTP and CTP in cell-free extracts was alleviated by increased Mg 2؉ concentration. The results support the thesis that the increased uptake of uridine in cells treated with growth factors is determined by a membrane-induced increase in intracellular free Mg 2؉ . Such increase would also accelerate the rate of translation-initiation and other coordinate responses that, unlike increased uridine uptake, are essential for cell proliferation. The rate of uridine uptake is suggested as a direct indicator of free cytosolic Mg 2؉ that drives the shift from quiescence to proliferation.translation-regulation ͉ cell proliferation control T reatment of quiescent cell cultures with growth factors elicits a coordinate response that includes increased rates of uptake of various substrates, acceleration of intermediary metabolism, and increased synthesis of protein and RNA that precede the onset of DNA synthesis (1). All of the early responses to growth factors that have been tested depend on the concentration of Mg 2ϩ in the cells as produced by varying the concentration of Mg 2ϩ in the medium (1-4). The most critical of the early responses for accelerating progress through G1 to S is the increased rate of protein synthesis (5, 6). The rate of protein synthesis in living cells and in cell-free systems is increased by raising the concentration of Mg 2ϩ to a certain level but is inhibited at still higher concentrations (4, 7). Cells self-adjust within a few hours from an externally imposed, abnormally high concentration of intracellular Mg 2ϩ , which inhibits protein synthesis, to a somewhat lower, stimulatory concentration (4). This autoregulation of intracellular Mg 2ϩ , with its accompanying rise in protein synthesis, is followed by a correspondingly delayed onset of DNA synthesis and attests to the physiological nature of proliferation control by Mg 2ϩ . The complexity of the regulation of protein ...

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supporting

confidence: 58%

supporting

confidence: 58%

Mg ²⁺ as activator of uridine phosphorylation in coordination with other cellular responses to growth factors

Vidair

Rubin

2005

Proc. Natl. Acad. Sci. U.S.A.

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“…Initial studies in cultured cells showed that applying insulin induced 20% higher intracellular Mg 2ϩ concentrations after 16 h (445). Later studies with EGF using the fluorescent probe mag-fura 2 showed an impressive fourfold increase of intracellular Mg 2ϩ from 0.3 to 1.4 mM after 20 min of epidermal growth factor (EGF) stimulation (199). The authors state that a rise in Mg 2ϩ precedes DNA synthesis, but coincides with and thus may contribute to increases in protein synthesis.…”

Section: E Cell Proliferationmentioning

confidence: 99%

Magnesium in Man: Implications for Health and Disease

Baaij

Hoenderop

Bindels

2015

Physiological Reviews

1,285

1,299

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“…Thus, pervanadate action on such a channel is a strong possibility. Indeed, in a recent report, Grubbs (1991) found that epidermal growth factor (EGF) increases both Mg2' uptake and intracellular free Mg2+ in BC,H1 myocytes, but does not alter Mg2+ efflux. In those cells, the dose-response curves for EGF stimulation of thymidine incorporation and Mg2+ uptake were similar, suggesting a relationship between increased Mg2' uptake and mitogenesis.…”

Section: Mg2+ As a Second Messengermentioning

confidence: 99%

Magnesium‐Dependent stimulation of protein synthesis by the insulin mimic, pervanadate

Barnes

Sykes

Smith

et al. 1995

Journal Cellular Physiology

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The insulin mimic, peroxide of vanadate (pervanadate), stimulated 35S-methionine incorporation into Xenopus oocyte protein in a Mg(2+)-dependent manner. Reducing the extracellular Mg2+ concentration from 1.0 to 0.1 mM decreased the pervanadate-stimulated component of incorporation by 35%; with 0.01 mM Mg2+ or lower, the pervanadate-stimulated component was abolished. In addition, reducing extracellular Mg2+ to 0.01 mM inhibited about 50% of the insulin-stimulated component of methionine incorporation. Mg2+ depletion had no effects on incorporation in controls or when protein synthesis was stimulated by Zn2+ or bovine growth hormone. Thus, not all substances that stimulated protein synthesis showed a dependence on extracellular Mg2+. Reducing extracellular Ca2+ had no effects on methionine incorporation in control cells or in cells stimulated by pervanadate or insulin. When oocytes maintained in a paraffin oil medium were brought into contact with a 0.5 microliter droplet of buffer containing the Mg2+ indicator dye, mag-fura-2, and pervanadate, apparent droplet Mg2+ decreased rapidly, indicating net uptake by the cells. Insulin also caused a net uptake of Mg2+. In contrast, apparent extracellular Mg2+ was constant when cells were in contact with droplets containing no effectors. Together, these data indicate that extracellular Mg2+, but not Ca2+, is involved in the stimulation of protein synthesis by pervanadate, and to a lesser extent by insulin. Pervanadate appears to induce a net uptake of Mg2+, and this change in membrane transport may be an early event in signalling the increase in translation.

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Effect of epidermal growth factor on magnesium homeostasis in BC3H1 myocytes

Cited by 38 publications

References 30 publications

Mg ²⁺ as activator of uridine phosphorylation in coordination with other cellular responses to growth factors

Mg ²⁺ as activator of uridine phosphorylation in coordination with other cellular responses to growth factors

Magnesium in Man: Implications for Health and Disease

Magnesium‐Dependent stimulation of protein synthesis by the insulin mimic, pervanadate

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Effect of epidermal growth factor on magnesium homeostasis in BC3H1 myocytes

Cited by 38 publications

References 30 publications

Mg 2+ as activator of uridine phosphorylation in coordination with other cellular responses to growth factors

Mg 2+ as activator of uridine phosphorylation in coordination with other cellular responses to growth factors

Magnesium in Man: Implications for Health and Disease

Magnesium‐Dependent stimulation of protein synthesis by the insulin mimic, pervanadate

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Product

Resources

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Mg ²⁺ as activator of uridine phosphorylation in coordination with other cellular responses to growth factors

Mg ²⁺ as activator of uridine phosphorylation in coordination with other cellular responses to growth factors