FWF - Pichia Lipidomics - Pichia Lipidomics (TRP 009)

The industrial yeast Pichia pastoris is widely used as an experimental system for the heterologous expression of proteins. Despite the extensive commercial use, fundamental biochemical, cell biological and molecular biological knowledge about this microorganism is largely missing. As a striking example, Pichia pastoris lipids have not been studied much in the past although it is obvious that knowledge about this class of biomolecules is highly important to understand the impact of biological (organelle) membranes on protein targeting and intracellular translocation of heterologously expressed proteins. For this reason, we wish to make use of the knowledge of our laboratory in yeast organelle analysis and lipid research and investigate lipids and biomembranes from Pichia pastoris in some detail. The goal of this study will be establishing the Pichia pastoris lipidome, and constructing Pichia pastoris mutant strains and variants with modified lipid profiles. A stepwise strategy with increasing specificity will lead from fundamental knowledge of Pichia pastoris cellular and organelle lipids to the application of this know-how to protein expression studies using engineered Pichia pastoris strains. First, we will perform lipidome analysis with Pichia pastoris organelle membranes which will include bulk lipids but also less abundant lipid components. Then, we will identify and characterize selected key enzymes of Pichia pastoris lipid metabolisms, and construct strains bearing deletions and/or over-expressions of selected prominent lipid biosynthetic and metabolic enzymes from Pichia pastoris which result in modified organelle lipid profiles. Basic phenotype studies of the novel strains will identify possible bottlenecks linked to lipid metabolism in Pichia pastoris. Finally, we will study expression of selected proteins, especially membrane bound proteins and secretory proteins, in the modified membrane lipid environment as proof of principle. This knowledge and these tools will be made public and available to the Pichia community for application to protein expression studies upon individual request and requirement. Thus, the proposed project will combine fundamental with applied research and add a novel facet to our knowledge of heterologous protein expression in Pichia pastoris.