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Wang 2019 J Biol Chem
Additional label 2019-02  +
Coupling states ROUTINE  + , OXPHOS  + , ET  +
Enzyme TCA cycle and matrix dehydrogenases  +
Has abstract Eukaryotic cell metabolism consists of pro
Eukaryotic cell metabolism consists of processes that generate available energy, such as glycolysis, the tricarboxylic acid (TCA) cycle and oxidative phosphorylation (OXPHOS) and those that consume it, including macromolecular synthesis, the maintenance of ionic gradients and cellular detoxification. By converting pyruvate to acetyl-CoA (AcCoA), the pyruvate dehydrogenase (PDH) complex (PDC) links glycolysis and the TCA cycle. Surprisingly, disrupting the connection between glycolysis and the TCA cycle by inactivation PDC has only minor effects on cell replication. However, the molecular basis for this metabolic re-equilibration is unclear. We report here that CRISPR/Cas9-generated PDH-knockout (PDH-KO) rat fibroblasts reprogramed their metabolism and their response to short-term c-Myc (Myc) oncoprotein overexpression. PDH-KO cells replicated normally, but produced surprisingly little lactate. They also exhibited higher rates of glycolysis and OXPHOS. In addition, PDH-KO cells showed altered cytoplasmic and mitochondrial pH, redox states, and mitochondrial membrane potential (ΔΨμ). Conditionally activated Myc expression affected some of these parameters in a PDH-dependent manner. PDH-KO cells had increased oxygen consumption rates in response to glutamate, but not to malate, and were depleted in all TCA cycle substrates between α-ketoglutarate and malate despite high rates of glutaminolysis, as determined by flux studies with isotopically labeled glutamine. Malate and pyruvate were diverted to produce aspartate, thereby potentially explaining the failure to accumulate lactate. We conclude that PDH-KO cells maintain proliferative capacity by utilizing glutamine to supply high rates of AcCoA-independent flux through the bottom portion of the TCA cycle while accumulating pyruvate and aspartate that rescue their redox defects. <small>Published under license by The American Society for Biochemistry and Molecular Biology, Inc.</small>
and Molecular Biology, Inc.</small>  +
Has editor [[Plangger M]]  +
Has info [ PMID: 30755479 Open Access]  +
Has publicationkeywords Myc (c-Myc)  + , Warburg effect  + , Fatty acid oxidation  + , Glutaminolysis  + , Pyruvate carboxylase (PC)  + , Reverse carboxylation  + , Tricarboxylic acid cycle (TCA cycle) (Krebs cycle)  +
Has title Wang H, Lu J, Kulkarni S, Zhang W, Gorka JE, Mandel JA, Goetzman ES, Prochownik EV (2019) Metabolic and oncogenic adaptations to pyruvate dehydrogenase inactivation in fibroblasts. J Biol Chem 294:5466-86.  +
Instrument and method Oxygraph-2k  +
Mammal and model Rat  +
MiP area Respiration  + , Genetic knockout;overexpression  +
Pathways F  + , N  + , S  + , NS  +
Preparation Permeabilized cells  + , Isolated mitochondria  + , Intact cells  +
Tissue and cell Fibroblast  +
Was published by MiPNetLab US PA Pittsburgh Goetzman ES +
Was published in journal J Biol Chem +
Was published in year 2019  +
Was written by Wang H + , Lu J + , Kulkarni S + , Zhang W + , Gorka JE + , Mandel JA + , Goetzman ES + , Prochownik EV +
Categories Publications
Modification date
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11:29:32, 26 July 2019  +
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