Regulation of Phosphatidic Acid Phosphatase by High Glucose in the Oleaginous Yeast Yarrowia lipolytica

Abstract

Phosphatidic acid phosphatase (PAP) catalyzes the conversion of phosphatidic acid to diacylglycerol, which is considered the committed step in triacylglycerol (TAG) biosynthesis. TAG biosynthesis in oleaginous microorganisms like Yarrowia lipolytica is typically triggered by high glucose amounts and results in cells accumulating lipids made mostly of TAGs. The objective of this work was to study the regulation of PAP during lipid accumulation induced by high glucose amounts. We hypothesized that the induction of TAG biosynthesis under these conditions should be mediated by PAP. In this work, we grew Y. lipolytica in a high glucose media (HGM) that favors lipid accumulation and in a low glucose media (LGM) where lipid accumulation is minimal. We measured PAP activity and lipid amounts throughout the cultivation period. Our results showed that, over time, the TAG amounts increased eight‐fold in the HGM cultures, while there was no increase in the LGM cultures. PAP activity was induced during TAG accumulation in HGM, which resulted in a two‐fold increase in activity. In contrast, PAP activity was down‐regulated in the LGM cultures, and that decrease coincided with the complete consumption of glucose in the medium. These results indicate that PAP plays a role in the regulation of lipid accumulation in Y. lipolytica.Support or Funding InformationThis project was supported by the Evans‐Allen Grant no.1005735 and Capacity BuildingGrants Program Grant no.1007503 from the USDA National Institute of Food and Agriculture.