scholarly journals Structural Determinants for Cross-talk between Pyruvate Dehydrogenase Kinase 3 and Lipoyl Domain 2 of the Human Pyruvate Dehydrogenase Complex

2006 ◽  
Vol 281 (37) ◽  
pp. 27197-27204 ◽  
Author(s):  
Shih-Chia Tso ◽  
Masato Kato ◽  
Jacinta L. Chuang ◽  
David T. Chuang
Keyword(s):  
Cross Talk ◽  
Pyruvate Dehydrogenase ◽  
Pyruvate Dehydrogenase Complex ◽  
Pyruvate Dehydrogenase Kinase ◽  
Structural Determinants ◽  
Dehydrogenase Complex ◽  
Lipoyl Domain

scholarly journals Evidence for existence of tissue-specific regulation of the mammalian pyruvate dehydrogenase complex

1998 ◽  
Vol 329 (1) ◽  
pp. 191-196 ◽  
Author(s):  
Melissa M. BOWKER-KINLEY ◽  
I. Wilhelmina DAVIS ◽  
Pengfei WU ◽  
A. Robert HARRIS ◽  
M. Kirill POPOV
Keyword(s):  
Tissue Distribution ◽  
Pyruvate Dehydrogenase ◽  
Pyruvate Dehydrogenase Complex ◽  
Pyruvate Dehydrogenase Kinase ◽  
Synthetic Analogue ◽  
Complex Activity ◽  
Acetyl Coa ◽  
Tissue Specific ◽  
Specific Regulation ◽  
Dehydrogenase Complex

Tissue distribution and kinetic parameters for the four isoenzymes of pyruvate dehydrogenase kinase (PDK1, PDK2, PDK3 and PDK4) identified thus far in mammals were analysed. It appeared that expression of these isoenzymes occurs in a tissue-specific manner. The mRNA for isoenzyme PDK1 was found almost exclusively in rat heart. The mRNA for PDK3 was most abundantly expressed in rat testis. The message for PDK2 was present in all tissues tested but the level was low in spleen and lung. The mRNA for PDK4 was predominantly expressed in skeletal muscle and heart. The specific activities of the isoenzymes varied 25-fold, from 50 nmol/min per mg for PDK2 to 1250 nmol/min per mg for PDK3. Apparent Ki values of the isoenzymes for the synthetic analogue of pyruvate, dichloroacetate, varied 40-fold, from 0.2 mM for PDK2 to 8 mM for PDK3. The isoenzymes were also different with respect to their ability to respond to NADH and NADH plus acetyl-CoA. NADH alone stimulated the activities of PDK1 and PDK2 by 20 and 30% respectively. NADH plus acetyl-CoA activated these isoenzymes nearly 200 and 300%. Under comparable conditions, isoenzyme PDK3 was almost completely unresponsive to NADH, and NADH plus acetyl-CoA caused inhibition rather than activation. Isoenzyme PDK4 was activated almost 2-fold by NADH, but NADH plus acetyl-CoA did not activate above the level seen with NADH alone. These results provide the first evidence that the unique tissue distribution and kinetic characteristics of the isoenzymes of PDK are among the major factors responsible for tissue-specific regulation of the pyruvate dehydrogenase complex activity.

scholarly journals Versatile Metabolic Adaptations ofRalstonia eutrophaH16 to a Loss of PdhL, the E3 Component of the Pyruvate Dehydrogenase Complex

2011 ◽  
Vol 77 (7) ◽  
pp. 2254-2263 ◽  
Author(s):  
Matthias Raberg ◽  
Jan Bechmann ◽  
Ulrike Brandt ◽  
Jonas Schlüter ◽  
Bianca Uischner ◽  
...  
Keyword(s):  
Pyruvate Dehydrogenase ◽  
Burkholderia Cepacia ◽  
Ralstonia Eutropha ◽  
Pyruvate Dehydrogenase Complex ◽  
Synthesis Rate ◽  
Wild Type ◽  
Dimerization Domain ◽  
Amino Terminal ◽  
Dehydrogenase Complex ◽  
Lipoyl Domain

ABSTRACTA previous study reported that the Tn5-induced poly(3-hydroxybutyric acid) (PHB)-leaky mutantRalstonia eutrophaH1482 showed a reduced PHB synthesis rate and significantly lower dihydrolipoamide dehydrogenase (DHLDH) activity than the wild-typeR. eutrophaH16 but similar growth behavior. Insertion of Tn5was localized in thepdhLgene encoding the DHLDH (E3 component) of the pyruvate dehydrogenase complex (PDHC). Taking advantage of the available genome sequence ofR. eutrophaH16, observations were verified and further detailed analyses and experiments were done.In silicogenome analysis revealed thatR. eutrophapossesses all five known types of 2-oxoacid multienzyme complexes and five DHLDH-coding genes. Of these DHLDHs, only PdhL harbors an amino-terminal lipoyl domain. Furthermore, insertion of Tn5inpdhLof mutant H1482 disrupted the carboxy-terminal dimerization domain, thereby causing synthesis of a truncated PdhL lacking this essential region, obviously leading to an inactive enzyme. The defined ΔpdhLdeletion mutant ofR. eutrophaexhibited the same phenotype as the Tn5mutant H1482; this excludes polar effects as the cause of the phenotype of the Tn5mutant H1482. However, insertion of Tn5or deletion ofpdhLdecreases DHLDH activity, probably negatively affecting PDHC activity, causing the mutant phenotype. Moreover, complementation experiments showed that different plasmid-encoded E3 components ofR. eutrophaH16 or of other bacteria, likeBurkholderia cepacia, were able to restore the wild-type phenotype at least partially. Interestingly, the E3 component ofB. cepaciapossesses an amino-terminal lipoyl domain, like the wild-type H16. A comparison of the proteomes of the wild-type H16 and of the mutant H1482 revealed striking differences and allowed us to reconstruct at least partially the impressive adaptations ofR. eutrophaH1482 to the loss of PdhL on the cellular level.

scholarly journals Expression and lipoylation in Escherichia coli of the inner lipoyl domain of the E2 component of the human pyruvate dehydrogenase complex

1993 ◽  
Vol 289 (1) ◽  
pp. 81-85 ◽  
Author(s):  
J Quinn ◽  
A G Diamond ◽  
A K Masters ◽  
D E Brookfield ◽  
N G Wallis ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Pyruvate Dehydrogenase ◽  
Pyruvate Dehydrogenase Complex ◽  
Structural Studies ◽  
Gene Encoding ◽  
E Coli ◽  
Inner Lipoyl Domain ◽  
Dehydrogenase Complex ◽  
Lipoyl Domain

The dihydrolipoamide acetyltransferase subunit (E2p) of mammalian pyruvate dehydrogenase complex has two highly conserved lipoyl domains each modified with a lipoyl cofactor bound in amide linkage to a specific lysine residue. A sub-gene encoding the inner lipoyl domain of human E2p has been over-expressed in Escherichia coli. Two forms of the domain have been purified, corresponding to lipoylated and non-lipoylated species. The apo-domain can be lipoylated in vitro with partially purified E. coli lipoate protein ligase, and the lipoylated domain can be reductively acetylated by human E1p (pyruvate dehydrogenase). Availability of the two forms will now allow detailed biochemical and structural studies of the human lipoyl domains.

Abstract TP268: Combination Therapy of Normobaric Oxygen With Hypothermia or Ethanol Modulates Pyruvate Dehydrogenase Complex in Thromboembolic Cerebral Ischemia

Stroke ◽  
2016 ◽  
Vol 47 (suppl_1) ◽  
Author(s):  
Alexa Thibodeau ◽  
Lipeng Cai ◽  
Changya Peng ◽  
Xiaokun Geng ◽  
Vicki Diaz ◽  
...  
Keyword(s):  
Combination Therapy ◽  
Protein Expression ◽  
Pyruvate Dehydrogenase ◽  
Pyruvate Dehydrogenase Complex ◽  
Pyruvate Dehydrogenase Kinase ◽  
Tissue Type ◽  
Energy Regulation ◽  
Normobaric Oxygen ◽  
Expression Levels ◽  
Dehydrogenase Complex

Background and Hypothesis: Pyruvate Dehydrogenase Complex (PDH) is a brain mitochondrial matrix enzyme that is inactivated during stroke injury. PDH impairment after stroke can be particularly devastating given PDH’s critical role in the conversion from anaerobic to aerobic energy metabolism. In this study, we evaluated the restoration of oxidative metabolism by measuring reactive oxygen species (ROS) levels and energy regulation by characterizing modulation of PDH and its inhibitor, pyruvate dehydrogenase kinase (PDK), with therapeutic combination of normobaric oxygen (NBO) plus either hypothermia (Hypo) or ethanol (EtOH). Methods: Sprague-Dawley rats were subjected to middle cerebral artery (MCA) occlusion induced with an autologous embolus, the more clinically relevant stroke model. One hour after occlusion, tissue-type plasminogen activator (t-PA) was administered alone or with NBO (60%), EtOH (1.0g/kg) or Hypo (33°C), either singly or in combination. PDH activity and ROS levels were measured at 3 and 24 hours after t-PA administration. Western blotting was used to detect PDH and PDK protein expression levels. Results: Administration of 60% NBO alone after reperfusion by t-PA treatment did not affect PDH activity. Under t-PA, compared to EtOH or Hypo alone, combined administration of NBO plus either EtOH or Hypo produced the greatest increases in PDH activity and protein expression levels, as well as the greatest decrease in PDK expression. Combination therapy also provided the most significant decline in ROS generation compared to any monotherapeutic approach. Conclusions: Reperfusion with t-PA followed by 60% NBO improves the efficacy of EtOH or Hypo in neuroprotection by ameliorating oxidative injury and improving metabolic regulation with PDH. Comparable neuroprotective effects were found when treating with either EtOH or Hypo, suggesting a similar mechanism and the possibility of substituting EtOH for Hypo in the clinical setting.

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