Lipid droplets (LDs) are fat storage organelles critical for energy and lipid metabolism. Upon nutrient exhaustion, cells consume LDs via gradual lipolysis or via lipophagy, the en bloc uptake of LDs into the vacuole. Here, we show that LDs dock to the vacuolar membrane via a contact site that is required for lipophagy in yeast. The LD-localized LDO proteins carry an intrinsically disordered region that directly binds vacuolar Vac8 to form vCLIP, the vacuolar-LD contact site. Nutrient limitation drives vCLIP formation, and its inactivation blocks lipophagy, resulting in impaired caloric restriction-induced longevity. We establish a functional link between lipophagy and microautophagy of the nucleus, both requiring Vac8 to form respective contact sites upon metabolic stress. In sum, we identify the tethering machinery of vCLIP and find that Vac8 provides a platform for multiple and competing contact sites associated with autophagy.
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http://dx.doi.org/10.1016/j.devcel.2024.01.014 | DOI Listing |
Contact (Thousand Oaks)
December 2024
Institute of Cell Dynamics and Imaging, University of Münster, Münster, Germany.
Lipid droplets frequently form contact sites with the membrane of the vacuole, the lysosome-like organelle in yeast. These vacuole lipid droplet (vCLIP) contact sites respond strongly to metabolic cues: while only a subset of lipid droplets is bound to the vacuole when nutrients are abundant, other metabolic states induce stronger contact site formation. Physical lipid droplet-vacuole binding is related to the process of lipophagy, a lipid droplet-specific form of microautophagy.
View Article and Find Full Text PDFDev Cell
March 2024
Institute of Cell Dynamics and Imaging, University of Münster, Von-Esmarch-Strasse 56, 48149 Münster, Germany; Cells in Motion Interfaculty Centre (CiM), University of Münster, Münster, Germany. Electronic address:
The lipid droplet (LD) organization proteins Ldo16 and Ldo45 affect multiple aspects of LD biology in yeast. They are linked to the LD biogenesis machinery seipin, and their loss causes defects in LD positioning, protein targeting, and breakdown. However, their molecular roles remained enigmatic.
View Article and Find Full Text PDFDev Cell
March 2024
Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, 10691 Stockholm, Sweden. Electronic address:
Lipid droplets (LDs) are fat storage organelles critical for energy and lipid metabolism. Upon nutrient exhaustion, cells consume LDs via gradual lipolysis or via lipophagy, the en bloc uptake of LDs into the vacuole. Here, we show that LDs dock to the vacuolar membrane via a contact site that is required for lipophagy in yeast.
View Article and Find Full Text PDFProc Natl Acad Sci U S A
May 2023
Cell Logistics Research Center, Gwangju Institute of Science and Technology, Gwangju 61005, South Korea.
Vac8, a yeast vacuolar protein with armadillo repeats, mediates various cellular processes by changing its binding partners; however, the mechanism by which Vac8 differentially regulates these processes remains poorly understood. Vac8 interacts with Nvj1 to form the nuclear-vacuole junction (NVJ) and with Atg13 to mediate cytoplasm-to-vacuole targeting (Cvt), a selective autophagy-like pathway that delivers cytoplasmic aminopeptidase I directly to the vacuole. In addition, Vac8 associates with Myo2, a yeast class V myosin, through its interaction with Vac17 for vacuolar inheritance from the mother cell to the emerging daughter cell during cell divisions.
View Article and Find Full Text PDFNat Commun
December 2021
Institute of Biochemistry and Molecular Biology, ZBMZ, Faculty of Medicine, University of Freiburg, 79104, Freiburg, Germany.
Autophagosomes form at the endoplasmic reticulum in mammals, and between the vacuole and the endoplasmic reticulum in yeast. However, the roles of these sites and the mechanisms regulating autophagosome formation are incompletely understood. Vac8 is required for autophagy and recruits the Atg1 kinase complex to the vacuole.
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