Increase in cellular triacylglycerol content and emergence of large ER-associated lipid droplets in the absence of CDP-DG synthase function.
Bottom Line: Using two species of fission yeast, we show that cycling cells deficient in the function of the ER-resident CDP-DG synthase Cds1 exhibit markedly increased triacylglycerol content and assemble large lipid droplets closely associated with the ER membranes.We demonstrate that these unusual structures recruit the triacylglycerol synthesis machinery and grow by expansion rather than by fusion.Our results suggest that interfering with the CDP-DG route of phosphatidic acid utilization rewires cellular metabolism to adopt a triacylglycerol-rich lifestyle reliant on the Kennedy pathway.
Affiliation: Temasek Life Sciences Laboratory, 117604 Singapore Department of Biological Sciences, National University of Singapore, 117543 Singapore.Show MeSH
Mentions: The cds1-9 allele was chosen for further characterization because it had a single amino acid substitution, changing cysteine at position 287 to arginine (C287R), and because it exhibited a tight conditional phenotype with respect to abnormal LD formation (Supplemental Figure S5 and Figure 5A). The CDP-DG synthase activity was markedly decreased in cds1-9 cells at 36°C (Figure 5B). The mutant protein appeared to bind PA nearly as well as the wild-type enzyme but exhibited a strongly decreased rate of catalysis (Figure 5C).
Affiliation: Temasek Life Sciences Laboratory, 117604 Singapore Department of Biological Sciences, National University of Singapore, 117543 Singapore.