Identification of pathways for the uptake of Coenzyme Q in Saccharomyces cerevisiae

Abstract

Coenzyme Q (ubiquinone or Q) is an essential molecule required for aerobic respiration that helps transfer electrons and protons in the electron transport chain. Many eukaryotic cells, including the yeast Saccharomyces cerevisiae, are capable of de novo synthesis of Q. S. cerevisiae coq mutants lack the ability to synthesize Q, but respiration and growth on a nonfermentable carbon source is rescued when mutant yeast are supplied with exogenous Q containing 6 or 4 isoprenyl side chain groups in the tail (Q6 or Q4). Deletion of certain endocytosis genes prevents exogenous Q6 from entering membranous organelles, including mitochondria (Padilla-López et al., Genetic evidence for the requirement of the endocytic pathway in the uptake of coenzyme Q6 in Saccharomyces cerevisiae, 2009 BBA 1788, 1238). However, these same gene deletions do not affect rescue by less hydrophobic Q4 (James et al., Complementation of coenzyme Q-deficient yeast by Q analogues requires the isoprenoid side chain, 2010 FEBS J 277, 2067). Here we examine selected yeast double mutants (coq2Δ ORFΔ) for the ability to grow on a nonfermentable carbon source in the presence of exogenously supplied Q6 or Q4. These studies will identify genes and pathways required for trafficking of exogenously supplied Q to the mitochondria, potentially providing insights into mechanisms of Q10 assimilation in humans. This research was supported by NSF MCB-1330803.