Regulation of the Saccharomyces cerevisiae EKI1-encoded Ethanolamine Kinase by Zinc Depletion

• Published in: The Journal of biological chemistry Vol. 281; no. 19; pp. 13110 - 13116
• Main Authors: Kersting, Michael C., Carman, George M.
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 12.05.2006; American Society for Biochemistry and Molecular Biology
• Subjects: Enzyme Induction - physiology; Ethanolamines - metabolism; Genotype; Mutation; Phospholipids - metabolism; Phosphotransferases (Alcohol Group Acceptor) - biosynthesis; Phosphotransferases (Alcohol Group Acceptor) - genetics; Promoter Regions, Genetic; Protein Binding; Saccharomyces cerevisiae; Saccharomyces cerevisiae - enzymology; Saccharomyces cerevisiae - genetics; Saccharomyces cerevisiae Proteins - metabolism; Trans-Activators - metabolism; Transcription Factors; Zinc - deficiency; Zinc - metabolism
• ISSN: 0021-9258; 1083-351X
• DOI: 10.1074/jbc.M601612200

Ethanolamine kinase catalyzes the committed step in the synthesis of phosphatidylethanolamine via the CDP-ethanolamine branch of the Kennedy pathway. Regulation of the EKI1-encoded ethanolamine kinase by the essential nutrient zinc was examined in Saccharomyces cerevisiae. The level of ethanolamine kinase activity increased when zinc was depleted from the growth medium. This regulation correlated with increases in the CDP-ethanolamine pathway intermediates phosphoethanolamine and CDP-ethanolamine, and an increase in the methylated derivative of phosphatidylethanolamine, phosphatidylcholine. The β-galactosidase activity driven by the PEKI1-lacZ reporter gene was elevated in zinc-depleted cells, indicating that the increase in ethanolamine kinase activity was attributed to a transcriptional mechanism. The expression level of PEKI1-lacZ reporter gene activity in the zrt1Δzrt2Δ mutant (defective in plasma membrane zinc transport) cells grown with zinc was similar to the activity expressed in wild-type cells grown without zinc. This indicated that EKI1 expression was sensitive to intracellular zinc. The zinc-mediated regulation of EKI1 expression was attenuated in the zap1Δ mutant defective in the zinc-regulated transcription factor Zap1p. Direct interactions between Zap1p and putative zinc-responsive elements in the EKI1 promoter were demonstrated by electrophoretic mobility shift assays. Mutations of these elements to a nonconsensus sequence abolished Zap1p-DNA interactions. Taken together, this work demonstrated that the zinc-mediated regulation of ethanolamine kinase and the synthesis of phospholipids via the CDP-ethanolamine branch of the Kennedy pathway were controlled in part by Zap1p.