PDK4/PDHK4

PDK4 is the fasting- and diabetes-responsive isoform of the pyruvate dehydrogenase kinase family, abundantly expressed in skeletal muscle, heart, liver and adipose tissue. Its gene is induced by glucocorticoids, thyroid hormone and PPAR-alpha/delta ligands during starvation, and the resulting phosphorylation of the PDH E1alpha subunit suppresses glucose oxidation in favor of fatty acid and BCAA catabolism. Persistent PDK4 upregulation is implicated in the hyperglycemia of type 2 diabetes and in muscle wasting, making PDK4 a prominent drug target for metabolic disease. Recombinant PDK4 is used for isozyme-selective inhibitor screening and studies of nutrient-driven metabolic switching.