Pyruvate Dehydrogenase Complexes in Metabolic Regulation

Pyruvate dehydrogenase complexes (PDCs) occupy a pivotal role at the interface of glycolysis and the tricarboxylic acid cycle by catalysing the oxidative decarboxylation of pyruvate to acetyl-CoA. Composed of three core enzymatic components—E1 (pyruvate dehydrogenase), E2 (dihydrolipoyl transacetylase) and E3 (dihydrolipoyl dehydrogenase)—these multi-megadalton assemblies orchestrate sequential catalytic steps while confining reactive intermediates within a flexible, lipoyl-domain-mediated shuttle. Regulation of PDC activity is achieved through reversible phosphorylation of E1 subunits by specific kinases and phosphatases, as well as through context-dependent post-translational modifications such as acetylation, which collectively modulate metabolic flux in response to cellular energy status, nutrient availability and signalling cues. This regulatory network has profound implications for physiological homeostasis and is implicated in pathological states ranging from metabolic syndromes to cancer, where alterations in PDC assembly, activity and post-translational modification underpin metabolic reprogramming and disease progression.

Research from Nature Portfolio

Recent cryo-electron microscopy studies have resolved the structural architecture of the native bacterial dihydrolipoyl transacetylase core at near-atomic resolution, revealing how multiple lipoyl domains engage transiently with catalytic sites to channel reaction intermediates efficiently. These reconstructions illuminate the docking interfaces between lipoyl domains and the peripheral subunit-binding domain, elucidating the molecular basis for substrate insertion and the mechanics of the flip-flop motion that underpins inter-site communication. Such high-resolution snapshots provide a blueprint for understanding how dynamic domain motions facilitate complex assembly and catalytic efficiency in PDCs across species.

Pyruvate Dehydrogenase Complexes in Metabolic Regulation publication trend

The graph below shows the total number of articles in pyruvate dehydrogenase complexes in metabolic regulation across all publications each year (not limited to Nature Index journals).

Technical terms

Pyruvate dehydrogenase complex (PDC): A multi-enzyme assembly that catalyses the conversion of pyruvate to acetyl-CoA, linking glycolysis to mitochondrial oxidation.

Lipoyl domain: A mobile protein domain that carries a lipoamide cofactor to shuttle reaction intermediates between catalytic sites within dehydrogenase complexes.

Acetyl-CoA: An essential metabolic intermediate that enters the tricarboxylic acid cycle and serves as a substrate for biosynthetic processes.

Phosphorylation: The reversible addition of phosphate groups to serine residues on PDC E1 subunits, mediated by specific kinases and phosphatases to regulate complex activity.

Acetylation: A post-translational modification involving the addition of an acetyl group to lysine residues, influencing protein interactions and enzyme assembly.

Lactylation: A post-translational modification of histones by lactate-derived groups, linking metabolic state to epigenetic regulation.

References

1. PDHX acetylation facilitates tumor progression by disrupting PDC assembly and activating lactylation-mediated gene expression. Protein & Cell (2024).
2. The Pyruvate Dehydrogenase Complexes: Structure-based Function and Regulation*. Journal of Biological Chemistry (2014).
3. Organization of the Cores of the Mammalian Pyruvate Dehydrogenase Complex Formed by E2 and E2 Plus the E3-binding Protein and Their Capacities to Bind the E1 and E3 Components*. Journal of Biological Chemistry (2003).
4. Structural Basis for Flip-Flop Action of Thiamin Pyrophosphate-dependent Enzymes Revealed by Human Pyruvate Dehydrogenase*. Journal of Biological Chemistry (2003).
5. Structure of the native pyruvate dehydrogenase complex reveals the mechanism of substrate insertion. Nature Communications (2021).
6. Subunit and Catalytic Component Stoichiometries of an in Vitro Reconstituted Human Pyruvate Dehydrogenase Complex*. Journal of Biological Chemistry (2009).