Office: 223 Schweitzer Hall
117 Schweitzer Hall
University of Missouri
Columbia, MO 65211
|BS||South Dakota State University||Brookings, S.D.||Chemistry|
|PhD||Michigan State University||East Lansing, Mich.||Biochemistry|
|NIH||Fellow, University of Texas||Austin, Tex.||Biochemistry|
Our group studied regulation of metabolism in plants, in particular, the pyruvate dehydrogenase complex (PDC) as a primary site at which photosynthetic carbon metabolism interacts with mitochondrial respiration and photorespiration. The regulation of this multienzyme complex has several layers including covalent modification by reversible phosphorylation (inactivation/deactivation). The regulation of the pyruvate dehydrogenase complex provides a site to manage the flow of carbon to the mitochondria during photosynthesis. Another form of this multienzyme complex is located in plastids where it functions in fatty acid and oil biosynthesis by providing the precursor acetyl-CoA for fatty acid, oil synthesis and a number of plant growth regulatory compounds. The final project is focusing on solving the bottleneck in the production of biodegradable plastic in plants by engineering components of PDC and related complexes that metobolize branded chair ketoacids.
Related projects include the molecular characterization of the component subunits of the pyruvate dehydrogenase complex and how these subunits are imported into the organelle and assembled into the complex. We are also charcterizing plant protein kinases and identifying their endogenous substrates. Protein kinases are essential components of many signal transduction pathways. Our group is part of a multi-institutional genomics project involving plant protein phosphorylation. We have projects involving three types of proteins kinase in three different subcellular components. Involvement in the plant protein phosphorylation genomics project is opening new ways of discovering regulatory mechanisms.
Tovar-Mendez A, Miernyk JA, Hoyos ME, Randall DD. A functional genomic analysis of Arabidopsis thaliana PP2C clade D. Protoplasma. 251:265-271. DOI: 10.1007/s00709-013-0526-7 (2014).
Broz AK, Mooney BP, Johnston ML, Miernyk JA, Randall DD. A Novel regulatory mechanism based upon a dynamic core structure for the mitochondrial pyruvate dehyrdrogenase complex. Mitochondrion. 19:144-153 (2014).
Hirani TA, Tovar-Mendez A, Miernyk JA, Randall DD. Asp295 stabilizes the active-site loop structure of pyruvate dehydrogenase, facilitating phosphorylation of Ser292 by pyruvate dehydrogenase-kinase. Enzyme Research. Article ID 939068 (2011).
Oxidation of an Adjacent Methionine Residue Inhibits Regulatory Seryl-Phosphorylation of Pyruvate Dehydrogenase. J.A. Miernyk, M.L. Johnston, S.C. Huber, A Tovar-Mendez, E. Hoyos and D.D. Randall. Proteomics Insights. 2 14-22 (2009).
Tovar-Mendez, A., Hirani, T.A., Miernyk, J.A., Randall, D.D. Analysis of the catalytic mechanism of pyruvate dehydrogenase kinase. Arch. Biochem. Biophys. 434: 159-168 (2005).
Tovar-Mendez, A, JA Miernyk, DD Randall. Regulalation of pyruvate dehydrogenase complex activity in plant cells. Eur. J. Biochem. 270: 1043-1049. Invited review. Journal Cover.
Szurmak, B, BP Mooney, JA Miernyk, DD Randall. Expression and assembly of Arabidopsis thaliana pyruvate dehydrogenase in insect cell cytoplasm. Prot. Purif. & Express. 28:357-361 (2003).
Tovar-Mendez, A, JA Miernyk, DD Randall. Histidine mutagenesis of Arabidopsis thaliana pyruvate dehydrogenase kinase. Eur. J. Biochem. 269: 2601-2606 (2002).