Identification of a phospholipase B encoded by the LPL1 gene in Saccharomyces cerevisiae.

Phospholipids also play a major role in maintaining the lipid droplet (LD) morphology. In our current study, deletion of LPL1 resulted in altered morphology of LDs and was confirmed by microscopic analysis. LPL1/YOR059c contains lipase specific motif GXSXG and acetate labeling in the LPL1 overexpressed strains depicted a decrease in glycerophospholipids and an increase in free fatty acids. The purified Lpl1p showed phospholipase activity with broader substrate specificity, acting on all glycerophospholipids primarily at sn-2 position and later at sn-1 position. Localization studies precisely revealed that Lpl1 is exclusively localized in the LD at the stationary phase. Site directed mutagenesis experiments clearly demonstrated that the lipase motif is vital for the phospholipase activity. In summary, our results demonstrate that yeast Lpl1 exerts phospholipase activity, plays a vital role in LD morphology, and its absence results in altered LD size. Based on the localization and enzyme activity we renamed YOR059c as LPL1 (LD phospholipase 1).