title: A sterol-enriched vacuolar microdomain mediates stationary phase lipophagy in budding yeast.
abstract: Stationary phase (stat-phase) is a poorly understood physiological state under which cells arrest proliferation and acquire resistance to multiple stresses. Lipid droplets (LDs), organelles specialized for cellular lipid homeostasis, increase in size and number at the onset of stat-phase. However, little is known about the dynamics of LDs under this condition. In this paper, we reveal the passage of LDs from perinuclear endoplasmic reticulum association to entry into vacuoles during the transition to stat-phase. We show that the process requires the core autophagy machinery and a subset of autophagy-related (Atg) proteins involved in selective autophagy. Notably, the process that we term stat-phase lipophagy is mediated through a sterol-enriched vacuolar microdomain whose formation and integrity directly affect LD translocation. Intriguingly, cells defective in stat-phase lipophagy showed disrupted vacuolar microdomains, implying that LD contents, likely sterol esters, contribute to the maintenance of vacuolar microdomains. Together, we propose a feed-forward loop in which lipophagy stimulates vacuolar microdomain formation, which in turn promotes lipophagy during stat-phase.
authors: Institute of Plant and Microbial Biology, Academia Sinica, Taipei 11529, Taiwan cwwang02@gate.sinica.edu.tw.
authors: Chao-Wen
authors: CW
authors: Wang
authors: Institute of Plant and Microbial Biology, Academia Sinica, Taipei 11529, Taiwan.
authors: Yu-Hsuan
authors: YH
authors: Miao
authors: Institute of Plant and Microbial Biology, Academia Sinica, Taipei 11529, Taiwan.
authors: Yi-Shun
authors: YS
authors: Chang
mesh_terms: D001343:Autophagy; D001692:Biological Transport; D007425:Intracellular Membranes / Q000378:metabolism*; D050356:Lipid Metabolism; D021962:Membrane Microdomains / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000166:cytology / Q000378:metabolism*; D059008:Time-Lapse Imaging; D014617:Vacuoles / Q000378:metabolism*