title: Lipid droplet autophagy in the yeast Saccharomyces cerevisiae.
abstract: Cytosolic lipid droplets (LDs) are ubiquitous organelles in prokaryotes and eukaryotes that play a key role in cellular and organismal lipid homeostasis. Triacylglycerols (TAGs) and steryl esters, which are stored in LDs, are typically mobilized in growing cells or upon hormonal stimulation by LD-associated lipases and steryl ester hydrolases. Here we show that in the yeast Saccharomyces cerevisiae, LDs can also be turned over in vacuoles/lysosomes by a process that morphologically resembles microautophagy. A distinct set of proteins involved in LD autophagy is identified, which includes the core autophagic machinery but not Atg11 or Atg20. Thus LD autophagy is distinct from endoplasmic reticulum-autophagy, pexophagy, or mitophagy, despite the close association between these organelles. Atg15 is responsible for TAG breakdown in vacuoles and is required to support growth when de novo fatty acid synthesis is compromised. Furthermore, none of the core autophagy proteins, including Atg1 and Atg8, is required for LD formation in yeast.
authors.affiliation: Molecular Cell Biology, University of Groningen, 9747 AG Groningen, Netherlands Institute of Molecular Biosciences, University of Graz, 8010 Graz, Austria.
authors.forename: Tim
authors.initials: T
authors.lastname: van Zutphen
authors.forename: Virginia
authors.initials: V
authors.lastname: Todde
authors.forename: Rinse
authors.initials: R
authors.lastname: de Boer
authors.forename: Martin
authors.initials: M
authors.lastname: Kreim
authors.forename: Harald F
authors.initials: HF
authors.lastname: Hofbauer
authors.forename: Heimo
authors.initials: H
authors.lastname: Wolinski
authors.forename: Marten
authors.initials: M
authors.lastname: Veenhuis
authors.forename: Ida J
authors.initials: IJ
authors.lastname: van der Klei
authors.forename: Sepp D
authors.initials: SD
authors.lastname: Kohlwein
mesh_terms: D001343:Autophagy / Q000235:genetics*; D000071190:Autophagy-Related Protein 8 Family; D000071183:Autophagy-Related Proteins; D002788:Cholesterol Esters / Q000378:metabolism; D002479:Inclusion Bodies / Q000235:genetics / Q000378:metabolism*; D050356:Lipid Metabolism / Q000235:genetics*; D008869:Microtubule-Associated Proteins / Q000378:metabolism; D011494:Protein Kinases / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins / Q000378:metabolism; D014280:Triglycerides / Q000378:metabolism; D014617:Vacuoles / Q000235:genetics / Q000378:metabolism; D033921:Vesicular Transport Proteins / Q000378:metabolism
chemical_list: C113757:ATG8 protein, S cerevisiae; C502923:Atg11 protein, S cerevisiae; D000071190:Autophagy-Related Protein 8 Family; D000071183:Autophagy-Related Proteins; D002788:Cholesterol Esters; D008869:Microtubule-Associated Proteins; D029701:Saccharomyces cerevisiae Proteins; D014280:Triglycerides; D033921:Vesicular Transport Proteins; D011494:Protein Kinases; C477823:ATG1 protein, S cerevisiae