Metabolism of exogenously applied fructose 1,6-bisphosphate in hypoxic vascular smooth muscle

Hardin, Christopher D.; Roberts, Tina M.

doi:10.1152/ajpheart.1994.267.6.h2325

Cited by 33 publications

(53 citation statements)

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“…Few studies have focused on this and only very little indirect evidence has been reported. In the experiment performed by Hardin and Roberts [18], it was shown by 13 C NMR that 20 mM FDP could lead to the production of […”

Section: Discussionmentioning

confidence: 99%

Enhancement of Hypothermic Heart Preservation with Fructose 1,6-Diphosphate

Niu¹,

Zhang²,

Ehringer³

et al. 1999

Journal of Surgical Research

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Section: Discussionmentioning

confidence: 99%

Enhancement of Hypothermic Heart Preservation with Fructose 1,6-Diphosphate

Niu¹,

Zhang²,

Ehringer³

et al. 1999

Journal of Surgical Research

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“…Markov et al (22) showed that FDP can restore the depressed glycolytic activity in ischemic myocardium by regulatory effects on the glycolytic pathway and also as a substrate for this pathway (21). Other investigators have also suggested that FDP can enter the cytosol in sufficient quantities to function as a direct substrate for glycolysis (10,18,27). No work has been done to address the issue of FDP transport in endothelial cells.…”

Section: Discussionmentioning

confidence: 99%

“…There are two proposed mechanisms to explain the increased glucose uptake seen with exogenous FDR First, FDP may enter the eytosol and provide a direct substrate for the glyeolytie pathway, entering at an energetically favorable level where ATP-dependent phosphorylation is not required. Seeond, FDP acts to stimulate glycolysis by increasing glycolytie or Krebs cycle enzyme activity, leading to increased glycolytic flux and oxidative metabolism (10).…”

Section: Discussionmentioning

confidence: 99%

The role of fructose-1, 6-diphosphate in cell migration and proliferation in an in vitro xenograft blood vessel model of vascular wound healing

Cohly

Stephens

Angel

et al. 1999

In Vitro Cell.Dev.Biol.-Animal

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Both smooth muscle cells and endothelial cells play an important role in vascular wound healing. To elucidate the role of fructose-1,6-diphosphate, cell proliferation and cell migration studies were performed with human endothelial cells and rat smooth muscle cells. To mimic blood vessels, endothelial and smooth muscle cells were used in 1:10, 1:5, and 1:1 concentrations, respectively, mimicking large-, mid-, and capillary-sized blood vessels. Cell migration was studied with fetal bovine serum-starved cells. For cell proliferation assay, cells were plated at 30-50% confluency and then starved. The cells were incubated for 48 h with fructose-1,6-diphosphate at (per ml) 10 mg, 1 mg, 500 microg, 250 microg, 100 microg, and 10 microg, pulsed with tritiated-thymidine and incubated with 1 N NaOH for 30 min at room temperature, harvested, and counted. For migration assay, confluent cells were starved, wounded, and incubated for 24 h with same concentrations of fructose-1,6-diphosphate as in proliferation assay. The cells were fixed and counted. Smooth muscle cell proliferation was inhibited by fructose-1,6-diphosphate at 10 mg/ml. In the xenograft models of 1:10, 1:5, and 1:1 fructose-1,6-diphosphate inhibited proliferation at 10 mg/ml. In migration studies 10 mg fructose-1,6-diphosphate per ml was inhibitory to both cell types. In large-, mid-, and capillary-sized blood vessels, fructose-1,6-diphosphate inhibited proliferation of both cell types at 10 mg/ml. At the individual cell level, fructose-1,6-diphosphate is nonstimulatory to proliferation of endothelial cells while inhibiting migration, and it acts on smooth muscle cells by inhibiting both proliferation and migration.

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“…1E). It has previously been shown that although F16BP is highly negatively charged it can enter the cell (31). In vitro the enzymatic inhibition of p58 by T3 can be overcome by addition of high concentrations of F16BP (20).…”

Section: Allosteric Inhibitor Phenylalanine Locks the M2pyk Tetramer mentioning

confidence: 99%

M2 pyruvate kinase provides a mechanism for nutrient sensing and regulation of cell proliferation

Morgan¹,

O’Reilly²,

Wear³

et al. 2013

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

155

247

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We show that the M2 isoform of pyruvate kinase (M2PYK) exists in equilibrium between monomers and tetramers regulated by allosteric binding of naturally occurring small-molecule metabolites. Phenylalanine stabilizes an inactive T-state tetrameric conformer and inhibits M2PYK with an IC 50 value of 0.24 mM, whereas thyroid hormone (triiodo-L-thyronine, T3) stabilizes an inactive monomeric form of M2PYK with an IC 50 of 78 nM. The allosteric activator fructose-1,6-bisphosphate [F16BP, AC 50 (concentration that gives 50% activation) of 7 μM] shifts the equilibrium to the tetrameric active Rstate, which has a similar activity to that of the constitutively fully active isoform M1PYK. Proliferation assays using HCT-116 cells showed that addition of inhibitors phenylalanine and T3 both increased cell proliferation, whereas addition of the activator F16BP reduced proliferation. F16BP abrogates the inhibitory effect of both phenylalanine and T3, highlighting a dominant role of M2PYK allosteric activation in the regulation of cancer proliferation. X-ray structures show constitutively fully active M1PYK and F16BP-bound M2PYK in an R-state conformation with a lysine at the dimer-interface acting as a peg in a hole, locking the active tetramer conformation. Binding of phenylalanine in an allosteric pocket induces a 13°rotation of the protomers, destroying the peg-in-hole R-state interface. This distinct T-state tetramer is stabilized by flipped out Trp/Arg side chains that stack across the dimer interface. Xray structures and biophysical binding data of M2PYK complexes explain how, at a molecular level, fluctuations in concentrations of amino acids, thyroid hormone, and glucose metabolites switch M2PYK on and off to provide the cell with a nutrient sensing and growth signaling mechanism.allosteric regulation | nutrient sensor | thyroid hormone T3 | Warburg effect T he last of 10 enzymatic steps used to convert glucose to pyruvate is carried out by pyruvate kinase (PYK), which transfers a phosphate from phosphoenolpyruvate to ADP to generate ATP. There are four human PYK isoforms (1); RPYK is restricted to erythrocytes, LPYK is found predominantly in liver and kidney, M1PYK is in muscle and brain, and M2PYK is found in fetal tissues and in proliferating cells. All four isoforms are active as tetramers; M1PYK is constitutively fully active, whereas R-, L-, and M2PYKs are activated by the effector molecule fructose-1,6-bisphosphate (F16BP) (2). M2PYK is a splice variant of the nonallosteric M1PYK isoform and differs by 22 amino acid residues (3). Recent quantification of the concentrations of constitutively fully active M1PYK and allosterically regulated M2PYK isoforms in both cancerous and control tissue samples has revealed that M2PYK is almost always the most abundant isoform in cancer cells, although it can also be predominant in matched control tissues (4). The up-regulation of the M2PYK isoform plays a key role in cancer metabolism (3) and explains the Warburg effect, in which proliferating cancer cells metabolize increas...

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Metabolism of exogenously applied fructose 1,6-bisphosphate in hypoxic vascular smooth muscle

Cited by 33 publications

References 0 publications

Enhancement of Hypothermic Heart Preservation with Fructose 1,6-Diphosphate

Enhancement of Hypothermic Heart Preservation with Fructose 1,6-Diphosphate

The role of fructose-1, 6-diphosphate in cell migration and proliferation in an in vitro xenograft blood vessel model of vascular wound healing

M2 pyruvate kinase provides a mechanism for nutrient sensing and regulation of cell proliferation

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