LAUSR

Yeast Sec14‐like phosphatidylinositol transfer proteins (PITPs) contain a hydrophobic cavity capable of accepting a single molecule of phosphatidylinositol (PI) or another molecule in a mutually exclusive manner. We report here that two yeast Sec14 family PITPs, Pdr16p (Sfh3p) and Pdr17p (Sfh4p), possess high‐affinity binding and transfer towards lanosterol. To our knowledge, this is the first identification of lanosterol transfer proteins. In addition, a pdr16Δpdr17Δ double mutant had a significantly increased level of cellular lanosterol compared with the corresponding wild‐type. Based on the lipid profiles of wild‐type and pdr16Δpdr17Δ cells grown in aerobic and anaerobic conditions, we suggest that PI‐lanosterol transfer proteins are important predominantly for the optimal functioning of the post‐lanosterol part of sterol biosynthesis.