Characterization of the isozymes of pyruvate dehydrogenase phosphatase: implications for the regulation of pyruvate dehydrogenase activity

Karpova, Tatiana S.; Danchuk, Svitlana; Kolobova, Elena; Popov, Kirill M.

doi:10.1016/j.bbapap.2003.08.010

Cited by 61 publications

(54 citation statements)

References 31 publications

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“…6 shows activities of PDP1 and PDP2 toward three phosphorylation sites of PDH2 and PDH1. Both PDP1 and PDP2 had higher activities toward site 2 than sites 1 and 3 of PDH1 as was reported previously (21). Similar site specificity was exerted by both the PDPs toward phosphorylation sites of PDH2.…”

Section: Specificity Of Four Pdk Isoenzymes Toward the Three Phosphorsupporting

confidence: 69%

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Characterization of Testis-specific Isoenzyme of Human Pyruvate Dehydrogenase

Korotchkina

Sidhu

Patel

2006

Journal of Biological Chemistry

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Pyruvate dehydrogenase (PDH), the first component of the human pyruvate dehydrogenase complex, has two isoenzymes, somatic cell-specific PDH1 and testis-specific PDH2 with 87% sequence identity in the ␣ subunit of ␣ 2 ␤ 2 PDH. The presence of functional testis-specific PDH2 is important for sperm cells generating nearly all their energy from carbohydrates via pyruvate oxidation. Kinetic and regulatory properties of recombinant human PDH2 and PDH1 were compared in this study. Site-specific phosphorylation/dephosphorylation of the three phosphorylation sites by four PDH kinases (PDK1-4) and two PDH phosphatases (PDP1-2) were investigated by substituting serines with alanine or glutamate in PDHs. PDH2 was found to be very similar to PDH1 as follows: (i) in specific activities and kinetic parameters as determined by the pyruvate dehydrogenase complex assay; (ii) in thermostability at 37°C; (iii) in the mechanism of inactivation by phosphorylation of three sites; and (iv) in the phosphorylation of sites 1 and 2 by PDK3. In contrast, the differences for PDH2 were indicated as follows: (i) by a 2.4-fold increase in binding affinity for the PDH-binding domain of dihydrolipoamide acetyltransferase as measured by surface plasmon resonance; (ii) by possible involvement of Ser-264 (site 1) of PDH2 in catalysis as evident by its kinetic behavior; and (iii) by the lower activities of PDK1, PDK2, and PDK4 as well as PDP1 and PDP2 toward PDH2. These differences between PDH2 and PDH1 are less than expected from substitution of 47 amino acids in each PDH2 ␣ subunit. The multiple substitutions may have compensated for any drastic alterations in PDH2 structure thereby preserving its kinetic and regulatory characteristics largely similar to that of PDH1. Mammalian pyruvate dehydrogenase complex (PDC)2 plays a central role in glucose oxidation by catalyzing the oxidative decarboxylation of pyruvic acid with formation of carbon dioxide, acetyl-CoA, NADH, and H ϩ (for reviews see Refs. 1-3). PDC is composed of multiple copies of the following three catalytic components: (i) pyruvate dehydrogenase (PDH) catalyzing the decarboxylation of pyruvate and reductive acetylation of the lipoyl moieties of dihydrolipoamide acetyltransferase (E2); (ii) E2 transferring acetyl moiety to CoA; (iii) and dihydrolipoamide dehydrogenase (E3) reoxidizing the reduced lipoyl moieties of E2 with the reduction of NAD ϩ to NADH (1-3). Forty eight to 60 subunits of E2and 12 subunits of E3-binding protein (BP), a noncatalytic component of mammalian PDC, form the central core of the multienzyme PDC, which binds 20 -30 tetramers of PDH, 6 -12 dimers of E3 and two regulatory enzymes, 1-2 copies of pyruvate dehydrogenase kinase (PDK), and 2-3 copies of pyruvate dehydrogenase phosphatase (PDP) (4, 5). PDK and PDP provide the finely tuned regulation of activity of PDC through reversible phosphorylation-dephosphorylation of PDH (and hence PDC) depending on cellular demand for glucose oxidation. Mammalian PDH is a tetramer consisting of two ␣ and two ␤ subunits. The hum...

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Section: Specificity Of Four Pdk Isoenzymes Toward the Three Phosphorsupporting

confidence: 69%

“…Site 1 is phosphorylated faster than the other sites; however, in PDC all three sites could potentially be phosphorylated resulting in the hyperphosphorylation. At the same time PDP1 and PDP2 dephosphorylate site 1 slower than the other sites (21). This would slow down the reactivation as reactivation of PDC requires dephosphorylation of all the three sites.…”

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confidence: 99%

Characterization of Testis-specific Isoenzyme of Human Pyruvate Dehydrogenase

Korotchkina

Sidhu

Patel

2006

Journal of Biological Chemistry

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“…Therefore, we cannot ascertain the extent to which PDP may be active in vivo, as activity varies with mitochondrial effector concentrations and the true substrate. In addition, in its natural state, PDP activity is affected by its association with the lipoyl domain on the PDH complex (allowing it to colocalize with phosphorylated E1␣; 14), and this cannot be fully reproduced with the synthetic peptide assay.…”

Section: Discussionmentioning

confidence: 99%

The relationship between human skeletal muscle pyruvate dehydrogenase phosphatase activity and muscle aerobic capacity

Love

LeBlanc

Inglis

et al. 2011

Journal of Applied Physiology

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Love LK, LeBlanc PJ, Inglis JG, Bradley NS, Choptiany J, Heigenhauser GJ, Peters SJ. The relationship between human skeletal muscle pyruvate dehydrogenase phosphatase activity and muscle aerobic capacity. J Appl Physiol 111: 427-434, 2011. First published May 19, 2011 doi:10.1152/japplphysiol.00672.2010.-Pyruvate dehydrogenase (PDH) is a mitochondrial enzyme responsible for regulating the conversion of pyruvate to acetyl-CoA for use in the tricarboxylic acid cycle. PDH is regulated through phosphorylation and inactivation by PDH kinase (PDK) and dephosphorylation and activation by PDH phosphatase (PDP). The effect of endurance training on PDK in humans has been investigated; however, to date no study has examined the effect of endurance training on PDP in humans. Therefore, the purpose of this study was to examine differences in PDP activity and PDP1 protein content in human skeletal muscle across a range of muscle aerobic capacities. This association is important as higher PDP activity and protein content will allow for increased activation of PDH, and carbohydrate oxidation. The main findings of this study were that 1) PDP activity (r 2 ϭ 0.399, P ϭ 0.001) and PDP1 protein expression (r 2 ϭ 0.153, P ϭ 0.039) were positively correlated with citrate synthase (CS) activity as a marker for muscle aerobic capacity; 2) E1␣ (r 2 ϭ 0.310, P ϭ 0.002) and PDK2 protein (r 2 ϭ 0.229, P ϭ0.012) are positively correlated with muscle CS activity; and 3) although it is the most abundant isoform, PDP1 protein content only explained ϳ18% of the variance in PDP activity (r 2 ϭ 0.184, P ϭ 0.033). In addition, PDP1 in combination with E1␣ explained ϳ38% of the variance in PDP activity (r 2 ϭ 0.383, P ϭ 0.005), suggesting that there may be alternative regulatory mechanisms of this enzyme other than protein content. These data suggest that with higher muscle aerobic capacity (CS activity) there is a greater capacity for carbohydrate oxidation (E1␣), in concert with higher potential for PDH activation (PDP activity). carbohydrate oxidation; PDH; PDP1; E1␣; E2; PDK2 PYRUVATE DEHYDROGENASE (PDH) is a multienzyme complex consisting of multiple copies of E1 (␣ and ␤), E2 (the core of the PDH complex), and E3 subunits, along with an E3 binding protein (E3BP), which serves to bind E3 to the complex (as reviewed by 1, 39). Each of these subunits (with the exception of E3BP) is involved in the conversion of pyruvate to acetylCoA in a stepwise manner. The complex is regulated largely via covalent modification by the addition of a phosphate group to at least one of its three serine residues located on the E1␣ subunit of the complex (15,31,33,34,37). Phosphorylation and inactivation are accomplished by a group of specific PDH kinases (PDK1-4), while dephosphorylation and activation are accomplished by a pair of PDH phosphatases (PDP1 and -2; Refs. 21, 34, 37). Each of these regulatory enzyme isoforms has different specificities and tissue expressions, with PDK2 and PDP1 being the most abundant isoforms in skeletal muscle (3, 11). Both isoforms...

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“…PDP1c (catalytic) activity strongly depends on its binding to the lipoyl domain of E2h requiring Ca 2ϩ (24, 94 -96). In contrast, PDP2c requires neither for its activity (95). Both PDP1c and PDP2c are able to dephosphorylate all three phosphorylation sites on E1h.…”

Section: Regulation Of Pdch By Phosphorylationmentioning

confidence: 99%

“…PDP1c exhibits a random mechanism of dephosphorylation (with relative rates of site 2 Ͼ site 3 Ͼ site 1), indicating a lack of site-site dependence for dephosphorylation. In contrast, PDP2c displays interdependence in dephosphorylation of site 1 with site 2 and site 3 separately, and no interaction between site 2 and site 3 (95). The crystal structure of PDP1c reveals a unique hydrophobic pocket on the surface to accommodate the lipoyl moiety of the lipoyl domain of E2 (97).…”

Section: Regulation Of Pdch By Phosphorylationmentioning

confidence: 99%

The Pyruvate Dehydrogenase Complexes: Structure-based Function and Regulation

Patel

Nemeria

Furey

et al. 2014

Journal of Biological Chemistry

493

389

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The pyruvate dehydrogenase complexes (PDCs) from all known living organisms comprise three principal catalytic components for their mission: E1 and E2 generate acetyl-coenzyme A, whereas the FAD/NAD ؉ -dependent E3 performs redox recycling. Here we compare bacterial (Escherichia coli) and human PDCs, as they represent the two major classes of the superfamily of 2-oxo acid dehydrogenase complexes with different assembly of, and interactions among components. The human PDC is subject to inactivation at E1 by serine phosphorylation by four kinases, an inactivation reversed by the action of two phosphatases. Progress in our understanding of these complexes important in metabolism is reviewed.

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Characterization of the isozymes of pyruvate dehydrogenase phosphatase: implications for the regulation of pyruvate dehydrogenase activity

Cited by 61 publications

References 31 publications

Characterization of Testis-specific Isoenzyme of Human Pyruvate Dehydrogenase

Characterization of Testis-specific Isoenzyme of Human Pyruvate Dehydrogenase

The relationship between human skeletal muscle pyruvate dehydrogenase phosphatase activity and muscle aerobic capacity

The Pyruvate Dehydrogenase Complexes: Structure-based Function and Regulation

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