Pyruvate dehydrogenase kinase isozyme 4 (PDK4)

Pyruvate dehydrogenase kinase isozyme 4 (PDK4) is a mitochondrial serine/threonine kinase that serves as a critical metabolic switch by regulating the pyruvate dehydrogenase complex (PDC) [6, 11]. It functions by phosphorylating and inactivating the E1 alpha subunit of PDC, which prevents the conversion of pyruvate into acetyl-CoA, thereby shifting cellular energy production from glucose oxidation to fatty acid oxidation [7, 18]. PDK4 expression is highly dynamic and is upregulated during fasting, exercise, and in response to high-fat diets to preserve glucose for essential tissues [3, 20]. In pathological states, chronic overactivity of PDK4 is a major contributor to metabolic inflexibility and insulin resistance in type 2 diabetes and obesity [1, 19]. Furthermore, PDK4 is frequently overexpressed in various cancers, supporting the Warburg effect by promoting aerobic glycolysis and protecting tumor cells from oxidative stress [2, 14]. Therapeutic targeting of PDK4 with small-molecule inhibitors aims to restore glucose oxidation, improve insulin sensitivity, and inhibit tumor progression or cardiac dysfunction in heart failure [15, 17].

Other names

Pyruvate dehydrogenase kinase 4[Pyruvate dehydrogenase (acetyl-transferring)] kinase isozyme 4, mitochondrialPDHK4Pyruvate dehydrogenase kinase isoform 4[Pyruvate dehydrogenase [lipoamide]] kinase isozyme 4, mitochondrial

PDK4 inhibits the pyruvate dehydrogenase complex (PDC) by phosphorylating the E1 alpha subunit (PDHE1-alpha) at specific serine residues. This phosphorylation prevents the conversion of pyruvate into acetyl-CoA, thereby suppressing glucose oxidation. Pharmacological inhibitors target the ATP-binding pocket or allosteric sites of PDK4 to block its kinase activity, leading to PDC activation and increased glucose disposal [5, 10, 15].