6-Phosphofructo-2-kinase/fructose-2,6-bisphosphatase: head-to-head with a bifunctional enzyme that controls glycolysis

Rider, Mark H.; Bertrand, Luc; Vertommen, Didier; Michels, Paul A.M.; Rousseau, Guy; Hue, Louis

doi:10.1042/bj20040752

Cited by 356 publications

(388 citation statements)

References 219 publications

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“…The bifunctional enzyme, 6‐phosphofructo‐2‐kinase/fructose 2,6‐bisphosphatase (PFK‐2), either produces or consumes the potent allosteric activator of PFK‐1, fructose 2,6‐bisphosphate. The kinase activity of the enzyme is activated by insulin and adrenergic signaling via phosphorylation, thus allowing the heart to normally alter its substrate selection depending on discrete external cues 14, 15. For example, protein kinase A (PKA)–mediated phosphorylation of PFK‐2 is sufficient to increase glucose use, even in the presence of lipids 16.…”

Section: Introductionmentioning

confidence: 99%

Cardiac Insulin Signaling Regulates Glycolysis Through Phosphofructokinase 2 Content and Activity

Humphries

Matsuzaki

Vadvalkar

et al. 2017

JAHA

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BackgroundThe healthy heart has a dynamic capacity to respond and adapt to changes in nutrient availability. Diabetes mellitus disrupts this metabolic flexibility and promotes cardiomyopathy through mechanisms that are not completely understood. Phosphofructokinase 2 (PFK‐2) is a primary regulator of cardiac glycolysis and substrate selection, yet its regulation under normal and pathological conditions is unknown. This study was undertaken to determine how changes in insulin signaling affect PFK‐2 content, activity, and cardiac metabolism.Methods and ResultsStreptozotocin‐induced diabetes mellitus, high‐fat diet feeding, and fasted mice were used to identify how decreased insulin signaling affects PFK‐2 and cardiac metabolism. Primary adult cardiomyocytes were used to define the mechanisms that regulate PFK‐2 degradation. Both type 1 diabetes mellitus and a high‐fat diet induced a significant decrease in cardiac PFK‐2 protein content without affecting its transcript levels. Overnight fasting also induced a decrease in PFK‐2, suggesting it is rapidly degraded in the absence of insulin signaling. An unbiased metabolomic study demonstrated that decreased PFK‐2 in fasted animals is accompanied by an increase in glycolytic intermediates upstream of phosphofructokianse‐1, whereas those downstream are diminished. Mechanistic studies using cardiomyocytes showed that, in the absence of insulin signaling, PFK‐2 is rapidly degraded via both proteasomal‐ and chaperone‐mediated autophagy.ConclusionsThe loss of PFK‐2 content as a result of reduced insulin signaling impairs the capacity to dynamically regulate glycolysis and elevates the levels of early glycolytic intermediates. Although this may be beneficial in the fasted state to conserve systemic glucose, it represents a pathological impairment in diabetes mellitus.

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Section: Introductionmentioning

confidence: 99%

Cardiac Insulin Signaling Regulates Glycolysis Through Phosphofructokinase 2 Content and Activity

Humphries

Matsuzaki

Vadvalkar

et al. 2017

JAHA

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“…Thus, it has many substrates, which usually are highly tissue specific. One such example is the bifunctional enzyme phosphofructokinase-2 (PFK2), which upon phosphorylation by PKA is converted to its phosphatase active mode in liver, but is stabilized in its kinase mode in heart, and is not a PKA substrate in skeletal muscle (1). Although PKA has been widely studied in most cells, the direct substrates of PKA are difficult to distinguish from downstream substrates that are phosphorylated as a result of the PKA activation.…”

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confidence: 99%

Identification of ChChd3 as a Novel Substrate of the cAMP-dependent Protein Kinase (PKA) Using an Analog-sensitive Catalytic Subunit

Schauble

King

Darshi

et al. 2007

Journal of Biological Chemistry

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Due to the numerous kinases in the cell, many with overlapping substrates, it is difficult to find novel substrates for a specific kinase. To identify novel substrates of cAMP-dependent protein kinase (PKA), the PKA catalytic subunit was engineered to accept bulky N 6 -substituted ATP analogs, using a chemical genetics approach initially pioneered with v-Src (1). Methionine 120 was mutated to glycine in the ATP-binding pocket of the catalytic subunit. To express the stable mutant C-subunit in Escherichia coli required co-expression with PDK1. This mutant protein was active and fully phosphorylated on Thr 197 and Ser 338 . Based on its kinetic properties, the engineered C-subunit preferred N 6 (benzyl)-ATP and N 6 (phenethyl)-ATP over other ATP analogs, but still retained a 30 M K m for ATP. This mutant recombinant C-subunit was used to identify three novel PKA substrates. One protein, a novel mitochondrial ChChd protein, ChChd3, was identified, suggesting that PKA may regulate mitochondria proteins.The cAMP-dependent protein kinase (PKA) 3 is expressed in all mammalian cells and plays a major role in processes such as metabolic control, memory, growth, development, and apoptosis. Thus, it has many substrates, which usually are highly tissue specific. One such example is the bifunctional enzyme phosphofructokinase-2 (PFK2), which upon phosphorylation by PKA is converted to its phosphatase active mode in liver, but is stabilized in its kinase mode in heart, and is not a PKA substrate in skeletal muscle (1). Although PKA has been widely studied in most cells, the direct substrates of PKA are difficult to distinguish from downstream substrates that are phosphorylated as a result of the PKA activation. A possible way to determine whether identified substrates are modified by the kinase directly or indirectly via an intermediary kinase is to engineer the ATP-binding pocket of the kinase in question to accept a bulky ATP analog that cannot be used by the wild type kinase. This strategy was developed initially for a tyrosine kinase, v-Src, (2) and has subsequently been used for other protein kinases (3). Shah et al. (4) found that a single mutation conferred specificity for ATP analogs that have a large substituent on the nitrogen at position 6 (N 6 ) on the purine ring of ATP. Two residues that were found within 5 Å of the N 6 position of ATP were based initially on the structures of PKA and CDK2 (cyclindependent kinase 2) since the crystal structure of v-Src was not available at the time (2). In v-Src, these residues are Val 323 and Ile 338 , while the corresponding residues in PKA are Val 104 and Met 120 . Although the Val 323 mutation was found to be not important for conferring specificity in v-Src, mutation of Ile 338 to Ala did alter the specificity of v-Src and allowed the enzyme to use an orthogonal bulky ATP analog. Once the crystal structure of hematopoietic cell kinase (Hck), a Src family tyrosine kinase was available, molecular modeling was employed to explore more fully the binding pocket of Hck to find t...

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“…It is central to normal protein folding and cell function. PFKFB4 expression is regulated by the transcriptional factor, known as hepatocyte nuclear factor-6 (Hnf-6) (Rider et al 2004). Hnf6-knockout caused diabetes in mice (Lannoy et al 2002).…”

Section: Novel Functions Of Ho-2mentioning

confidence: 99%

“…Hnf6-knockout caused diabetes in mice (Lannoy et al 2002). PFKFB4 protein phosphorylation, mediated by the c-AMP dependent protein kinase A (PKA) caused a fall in fructose 2,6 bisphosphate (F-2,6-P 2 ) in liver, thereby increasing gluconeogenesis with concomitantly reducing glycolysis (Rider et al 2004).…”

Section: Novel Functions Of Ho-2mentioning

confidence: 99%

Emerging Roles of Cadmium and Heme Oxygenase in Type-2 Diabetes and Cancer Susceptibility

Satarug

2012

Tohoku J. Exp. Med.

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Many decades after an outbreak of severe cadmium poisoning, known as Itai-itai disease, cadmium continues to pose a significant threat to human health worldwide. This review provides an update on the effects of this environmental toxicant cadmium, observed in numerous populations despite modest exposure levels. In addition, it describes the current knowledge on the link between heme catabolism and glycolysis. It examines novel functions of heme oxygenase-2 (HO-2) that protect against type 2-diabetes and obesity, which have emerged from diabetic/obese phenotypes of the HO-2 knockout mouse model. Increased cancer susceptibility in type-2 diabetes has been noted in several large cohorts. This is a cause for concern, given the high prevalence of type-2 diabetes worldwide. A lifetime exposure to cadmium is associated with pre-diabetes, diabetes, and overall cancer mortality with sex-related differences in specific types of cancer. Liver and kidney are target organs for the toxic effects of cadmium. These two organs are central to the maintenance of blood glucose levels. Further, inhibition of gluconeogenesis is a known effect of heme, while cadmium has the propensity to alter heme catabolism. This raises the possibility that cadmium may mimic certain HO-2 deficiency conditions, resulting in diabetic symptoms. Intriguingly, evidence has emerged from a recent study to suggest the potential interaction and co-regulation of HO-2 with the key regulator of glycolysis: 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase 4 (PFKFB4). HO-2 could thus be critical to a metabolic switch to cancer-prone cells because the enzyme PFKFB and glycolysis are metabolic requirements for cell proliferation and resistance to apoptosis.

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6-Phosphofructo-2-kinase/fructose-2,6-bisphosphatase: head-to-head with a bifunctional enzyme that controls glycolysis

Cited by 356 publications

References 219 publications

Cardiac Insulin Signaling Regulates Glycolysis Through Phosphofructokinase 2 Content and Activity

Cardiac Insulin Signaling Regulates Glycolysis Through Phosphofructokinase 2 Content and Activity

Identification of ChChd3 as a Novel Substrate of the cAMP-dependent Protein Kinase (PKA) Using an Analog-sensitive Catalytic Subunit

Emerging Roles of Cadmium and Heme Oxygenase in Type-2 Diabetes and Cancer Susceptibility

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