The resident mitochondrial protein kinases (mPKs) comprising pyruvate dehydrogenase kinases (PDKs), and branched-chain 1-ketoacid dehydrogenase kinase (BCK) are the molecular switches that control carbohydrate and branched-chain amino acid degradation. Mitochondrial PDKs (isoforms 1, 2, 3 and 4) down-regulate activity of the mitochondrial pyruvate dehydrogenase complex by reversible phosphorylation, in response to hormonal and nutritional stimuli. Certain PDK isoforms are over-expressed in disease states such as type 2 diabetes, obesity and cancer, resulting in decreased glucose oxidation. Towards understanding the structure and function of these PDKs, the P.I.'s laboratory has solved the crystal structures for three (PDK1, PDK3 and PDK4) of the four PDK isoforms and various PDK-inhibitor/activator complexes. Based on these advances, the P.I. proposes to continue investigation into the structure, function and regulation of mammalian PDKs.
The Specific Aims are: 1) To decipher the allosteric mechanisms by which the L2 domain and the synthetic ligands modulate PDK activities;2) To offer biochemical and structural basis for the hyperactivity of PDK4 and to identify the E1p substrate-binding site in this kinase isoform;3) To isolate a new generation of small-molecule inhibitors that are specific for PDK4 by high-through-put screening and characterize these novel inhibitors both in vitro and in cell culture. Standard methods including X-ray crystallography, isothermal titration calorimetry, kinase activity assays and the high-through-put screening method will be employed to achieve these Specific Aims. The availability of PDK4-specific inhibitors will foster new strategies to mitigate defective glucose oxidation in obesity and type 2 diabetes.
The mitochondrial protein kinases to be studied in this project are molecular switches that control carbohydrate and amino acid degradation in the liver and skeletal muscle. Aberrant functions of these protein kinases have been implicated in obesity and type 2 diabetes. Understanding the structure and function of pyruvate dehydrogenase kinase (PDK) isoforms and the development of PDK isoform #4-specific inhibitors will foster new strategies to mitigate defective glucose oxidation in these human diseases.
|Scheuermann, Thomas H; Brautigam, Chad A (2015) High-precision, automated integration of multiple isothermal titration calorimetric thermograms: new features of NITPIC. Methods 76:87-98|
|Padrick, Shae B; Deka, Ranjit K; Chuang, Jacinta L et al. (2010) Determination of protein complex stoichiometry through multisignal sedimentation velocity experiments. Anal Biochem 407:89-103|
|Kato, Masato; Wynn, R Max; Chuang, Jacinta L et al. (2008) Structural basis for inactivation of the human pyruvate dehydrogenase complex by phosphorylation: role of disordered phosphorylation loops. Structure 16:1849-59|
|Kato, Masato; Li, Jun; Chuang, Jacinta L et al. (2007) Distinct structural mechanisms for inhibition of pyruvate dehydrogenase kinase isoforms by AZD7545, dichloroacetate, and radicicol. Structure 15:992-1004|
|Li, Jun; Machius, Mischa; Chuang, Jacinta L et al. (2007) The two active sites in human branched-chain alpha-keto acid dehydrogenase operate independently without an obligatory alternating-site mechanism. J Biol Chem 282:11904-13|
|Brautigam, Chad A; Wynn, R Max; Chuang, Jacinta L et al. (2006) Structural insight into interactions between dihydrolipoamide dehydrogenase (E3) and E3 binding protein of human pyruvate dehydrogenase complex. Structure 14:611-21|
|Kato, Masato; Wynn, R Max; Chuang, Jacinta L et al. (2006) A synchronized substrate-gating mechanism revealed by cubic-core structure of the bovine branched-chain alpha-ketoacid dehydrogenase complex. EMBO J 25:5983-94|
|Chuang, David T; Chuang, Jacinta L; Wynn, R Max (2006) Lessons from genetic disorders of branched-chain amino acid metabolism. J Nutr 136:243S-9S|
|Tso, Shih-Chia; Kato, Masato; Chuang, Jacinta L et al. (2006) Structural determinants for cross-talk between pyruvate dehydrogenase kinase 3 and lipoyl domain 2 of the human pyruvate dehydrogenase complex. J Biol Chem 281:27197-204|
|Li, Jun; Wynn, R Max; Machius, Mischa et al. (2004) Cross-talk between thiamin diphosphate binding and phosphorylation loop conformation in human branched-chain alpha-keto acid decarboxylase/dehydrogenase. J Biol Chem 279:32968-78|
Showing the most recent 10 out of 12 publications