Submitted to: American Society of Plant Biologists Annual Meeting
Publication Type: Abstract Only
Publication Acceptance Date: 3/21/2005
Publication Date: N/A
Citation: Interpretive Summary:
Technical Abstract: Pyruvate dehydrogenase kinase (PDK) is the primary regulator of flux through the mitochondrial pyruvate dehydrogenase complex (PDC). The PDK catalyzes phosphorylation of Ser residues in the alpha subunit of the pyruvate dehydrogenase (E1alpha). Phosphorylation of E1alpha inactivates the PDC. In mammalian cells there are four forms of PDK that allow control of PDC under different metabolic conditions. In plants one (A. thaliana) or two (maize, rice, and soybean) forms of PDK are present. An important question is how metabolism can be regulated in a complex eukaryote that has only one PDK? To address this, we initially determined the pattern expression of PDK in A. thaliana using both RT-PCR and expression of a promoter-GUS fusion. The results indicate that PDK is expressed in all organs: cotyledons ~ leaves >> stems> flowers > roots. In green organs the highest level of expression occurs in cotyledons, leaves, and pedicels. In floral tissue PDK is expressed in sepals and pollen, and to a lesser degree in siliques. The lowest expression levels were in roots and seeds. The data support the well-documented role of PDK in photosynthetic cells. The high expression in pollen suggests PDK has a role in pollen metabolism before and/or during pollination. This research is supported by a grant from NFS and the Food for the 21st-century Program at the University of Missouri.