title: Lipid droplets are central organelles for meiosis II progression during yeast sporulation.
abstract: Neutral lipids, predominantly triacylglycerol (TAG) and sterol ester, are stored within the cellular organelles termed lipid droplets (LDs). Although it is believed that the major function of LDs is to supply the cell with energy and membranes, little is known about the cellular events directly involving LDs and their contents. In this study, we provide cytological evidence that LDs form direct contacts with the prospore membrane (PSM) that is synthesized de novo during meiosis II to sequester the dividing nuclei in sporulating yeast. Lipidomic analyses indicate that TAG lipolysis releases free fatty acids at a time that correlates well with meiosis II progression, concomitant with phospholipid remodeling. Mutants lacking TAG or impaired of TAG hydrolysis show spore wall assembly defects, supporting a role for TAG and/or its metabolites in spore wall morphogenesis. Not only does LD integrity influence spore wall assembly, LDs are also essential for other aspects of spore development. Yeast cells lacking LDs are severely defective in PSM growth and organization and display disrupted spindles, producing dead spores or even failing to form spores. Together these results link LD physiology directly to a unique membrane morphogenesis process critical for development.
authors.affiliation: Institute of Molecular Biology, Academia Sinica, Nankang, Taipei 11529, Taiwan.
authors.forename: Tzu-Han
authors.initials: TH
authors.lastname: Hsu
authors.affiliation: Institute of Molecular Biology, Academia Sinica, Nankang, Taipei 11529, Taiwan.
authors.forename: Rey-Huei
authors.initials: RH
authors.lastname: Chen
authors.affiliation: Institute of Plant and Microbial Biology, Academia Sinica, Nankang, Taipei 11529, Taiwan.
authors.forename: Yun-Hsin
authors.initials: YH
authors.lastname: Cheng
authors.affiliation: Institute of Plant and Microbial Biology, Academia Sinica, Nankang, Taipei 11529, Taiwan cwwang02@gate.sinica.edu.tw.
authors.forename: Chao-Wen
authors.initials: CW
authors.lastname: Wang
mesh_terms: D002462:Cell Membrane / Q000502:physiology; D002473:Cell Wall / Q000378:metabolism; D066292:Lipid Droplets / Q000378:metabolism* / Q000502:physiology*; D050356:Lipid Metabolism / Q000502:physiology; D008055:Lipids / Q000502:physiology; D008066:Lipolysis / Q000502:physiology; D008540:Meiosis / Q000502:physiology; D015388:Organelles / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000378:metabolism; D013172:Spores, Fungal / Q000378:metabolism
chemical_list: D008055:Lipids; D029701:Saccharomyces cerevisiae Proteins